Once-through pump

This application is based on Application Ser. Nos. 2001001625 and 2001192526, filed in Japan on Jan. 9, 2001 and Jun. 26, 2001, the contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a once-through pump (e.g., once-through blower) which is adapted to be incorporated in a domestic air conditioner, an automotive air conditioner, etc., for accelerating fluid in a flow passage while passing therethrough, and more specifically, it relates to a once-through pump which is capable of improving the pumping (or air-blowing) efficiency to thereby reduce noise in operation and achieve a sufficient pumping flow rate as well even within a limited design space.

2. Description of the Related Art

FIG. 25

is a cross sectional side view schematically illustrating a known once-through pump such as, for example, a once-through blower.

FIG. 26

is an enlarged cross sectional view illustrating the operation of fluid F in the vicinity of an impeller

100

in FIG.

25

.

In

FIG. 25

, a heat exchanger

1

of an air conditioner is arranged on the upstream side of a flow passage P such as a channel, duct, etc., through which the fluid F such as air (see an arrow) passes.

The impeller

100

of a cylindrical shape, which constitutes the main body of the once-through blower, is integrally formed of a resin or the like, and is rotatably supported within the flow passage P.

The impeller

100

is driven to rotate around a rotation shaft or drive shaft

200

by the driving force of an unillustrated motor in a direction of arrow B.

The impeller

100

is provided on the outer periphery thereof with a multitude of vanes

101

(an array of vanes) at equal intervals in a symmetric relation with respect to the drive shaft

200

.

Moreover, a tongue portion

2

is formed on the inner wall of the flow passage P for providing a cutoff structure, so that a portion of the flow passage P on the outer periphery of the impeller

100

is made into a bent or curved configuration about the tongue portion

2

.

As a result, the fluid F in the impeller

100

generates a swirl or vortex E (see a clockwise arrow in

FIG. 26

) at a part near the tip of the tongue portion

2

, as illustrated in

FIG. 26

, whereby the fluid F is accelerated while passing between adjacent ones of the rotating vanes

101

.

That is, the fluid F located on the upstream side of the impeller

100

is sucked into the impeller

100

under a negative pressure of the vortex E, and discharged toward the downstream side of the impeller

100

while being accelerated by the centrifugal force of the impeller

100

acting in a rotational direction B.

In general, the once-through blower comprising the impeller

100

illustrated in FIG.

25

and

FIG. 26

has a merit in that the amount of blast or air flow (i.e., flow rate) can be arbitrarily set by variably designing the size or dimensions of the flow passage P in a thrust direction of the drive shaft

200

.

However, the condition of generation of the vortex E becomes unstable when some load is applied to a forward end (i.e., upstream side) or a rear end (i.e., downstream side) of the impeller

100

in practical use, thus making the blast or air-blowing function thereof unstabilized. As a result, the blower can only accommodate at most about 5 mmAq (50 Pa) as its tolerance to load.

In addition, noise generated by the vanes

101

would become violent under the influence of a negative pressure generated by the vanes

101

passing by the neighborhood of the vortex E.

With the known once-through blower (once-through pump) as described above, the tongue portion

2

is provided on the inner wall of the flow passage P at a location at which the impeller

100

is mounted so as to form the cutoff structure of the bent or curved configuration inside the flow passage P, so that a swirl or vortex E is thereby generated in the impeller

100

, thus accelerating the fluid F in the flow passage P. As a consequence, there arise the following problems: the acceleration performance of the blower is unstable and the acceleration efficiency thereof is low; it is easy to generate noise; and it is impossible to generate a sufficient amount of blast or air flow within a limited design space.

SUMMARY OF THE INVENTION

The present invention is intended to obviate the various problems as referred to above, and has for its object to provide a once-through pump which is improved in its pumping efficiency, thereby making it possible to reduce noise and achieve a sufficient amount of pumping fluid or flow rate even within a limited space as designed.

Bearing the above object in mind, according to a first aspect of the present invention, there is provided a once-th rough pump for accelerating fluid in a flow passage while passing the fluid through the flow passage, the pump comprising: a cylindrical impeller rotatably supported in the flow passage; a plurality of vanes provided on the outer periphery of the impeller; a drive shaft for driving the impeller to rotate; wherein the impeller has a substantially D-shaped cross sectional configuration with a suction side, at which the fluid is sucked into the impeller, being formed into a straight portion, and each of the vanes has a positive vane angle with respect to a fluid advancing direction in the straight portion. With the above construction, a once-through pump can be obtained which is able to improve the air-blowing efficiency, reduce operation noise, and achieve a sufficient amount of blast or flow rate even within a limited design space.

In a preferred form of the first aspect of the present invention, the impeller comprises: a curvable wheel portion positioned at a side end face of an outer periphery of the impeller; and straight portion forming means for forming the straight portion in a part of the wheel portion; wherein the straight portion forming means comprises a guide plate member of a substantially D-shaped configuration disposed inside the wheel portion; and the wheel portion comprises a chain member which is slidable along an outer periphery of the guide plate member, the wheel portion being driven to rotate by means of a drive shaft which is in engagement with the chain member. With the above construction, a once-through pump can be obtained which is able to easily implement the impeller of the D-shaped configuration, reduce operation noise, and achieve a sufficient amount of blast or flow rate even within a limited design space.

According to a second aspect of the present invention, there is provided a once-through pump for accelerating fluid in a fluid passage, the pump comprising: an impeller provided in the flow passage and having an axis of rotation arranged in a diametrical direction of the flow passage; a vane array including a plurality of vanes provided on an outer periphery of the impeller; and a drive shaft for driving the impeller to rotate; wherein the impeller comprises: a belt-like connecting portion for connecting and arranging the respective vanes of the vane array with one another at substantially equal intervals; a single large wheel for supporting the belt-like connecting portion from its inside; and at least one small wheel disposed at a location in opposition to and apart from the large wheel for supporting the belt-like connecting portion from its inside; wherein the vane array arranged integrally with the belt-like connecting portion includes an arc-shaped centrifugal vane array and a linear vane array compulsorily formed by the large wheel and the at least one small wheel, and the small wheel forms the linear vane array at a suction side of the fluid with respect to the impeller, and the large wheel forms the centrifugal vane array at a discharge side of the fluid with respect to the impeller. With the above construction, a once-through pump can be obtained which is able to improve the pumping efficiency, reduce operation noise, and achieve a sufficient amount of pumping flow or flow rate even within a limited design space.

According to a preferred form of the second aspect of the present invention, the drive shaft together with the at least one small wheel forms the linear vane array, and the impeller has a substantially D-shaped cross sectional configuration. Thus, a once-through pump can be obtained which is able to reduce operation noise, and achieve a sufficient amount of pumping flow or flow rate even within a limited design space.

According to another preferred form of the second aspect of the present invention, the small wheel is formed integrally with the drive shaft to provide a pair of linear vane arrays with the small wheel arranged at their center, and the impeller has a cross sectional shape formed into a substantially spindle-shaped configuration. Thus, a once-through pump can be obtained which is able to simplify the pump construction, and achieve a sufficient amount of pumping flow or flow rate even within a limited design space.

According to a further preferred form of the second aspect of the present invention, the belt-like connecting portion has a plurality of outer periphery support sections arranged at equal intervals along a rotational direction of the impeller, and the respective vanes of the vane array are fixedly secured to the outer periphery support sections, and each arranged so as to maintain a constant vane angle. Thus, a once-through pump can be obtained which is able to provide stable pumping performance, and achieve a sufficient amount of pumping flow or flow rate even within a limited design space.

According to a still further preferred form of the second aspect of the present invention, the large wheel has a plurality of outer peripheral teeth arranged at equal intervals along a rotational direction of the large wheel, and the belt-like connecting portion has a plurality of inner peripheral teeth arranged at equal intervals in a rotational direction of the impeller so as to engage the outer peripheral teeth of the large wheel, and the outer peripheral teeth and the inner peripheral teeth are tuned to support dimensions of the cross sectional shape of the impeller at a plurality of locations including opposite axial ends of the impeller for preventing occurrence of distortion of the vanes at the opposite axial ends of the impeller. Thus, a once-through pump can be obtained which is able to avoid the generation of vibration, and achieve a sufficient amount of pumping flow or flow rate even within a limited design space.

According to a yet further preferred form of the second aspect of the present invention, the inner peripheral teeth of the belt-like connecting portion are formed integrally with the outer periphery support sections at a same pitch at which the outer periphery support sections are arranged. Thus, a once-through pump can be obtained which is able to improve precision in manufacturing the belt-like connecting portion, and achieve a sufficient amount of pumping flow or flow rate even within a limited design space.

According to a further preferred form of the second aspect of the present invention, each of the inner peripheral teeth of the belt-like connecting portion and the outer periphery support sections has a deformable quadrilateral cross sectional shape, and the outer peripheral teeth of the large wheel are formed into slant embossed shapes with respect to a rotational direction of the impeller and the large wheel, so that the quadrilateral cross sectional shape can be deformed in a direction to increase the vane angle of each of the vanes. Thus, a once-through pump can be obtained which is able to arbitrarily change the vane angle and improve the pumping performance.

According to a further preferred form of the second aspect of the present invention, the large wheel is formed integrally with the drive shaft. Thus, a once-through pump can be obtained which is able to change the vane angle in a centrifugal vane array in a reliable manner.

The above and other objects, features and advantages of the present invention will become more readily apparent to those skilled in the art from the following detailed description of preferred embodiments of the present invention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a cross sectional side view schematically illustrating an impeller according to a first embodiment of the present invention.

FIG. 2

is an perspective view illustrating, on an enlarged scale, essential portions of a once-through pump according to the first embodiment of the present invention.

FIG. 3

is a perspective view illustrating a concrete example of a straight portion forming means according to the first embodiment of the present invention.

FIG.

4

A and

FIG. 4B

are side views illustrating a straight portion and an arc portion, respectively, according to the first embodiment of the present invention.

FIG.

5

A and

FIG. 5B

are explanatory views illustrating velocity triangles at the straight portion and at the arc portion, respectively, according to the vane angles of vanes according to the first embodiment of the present invention.

FIG. 6

is a side elevation illustrating a curved portion between a straight portion and an arc portion according to a second embodiment of the present invention.

FIGS. 7A and 7B

are perspective views illustrating a connecting portion formed into a plate-shaped configuration according to a third embodiment of the present invention.

FIG. 8

is a cross sectional view illustrating a connecting portion according to a fourth embodiment of the present invention.

FIG. 9

is a side elevation illustrating a connecting portion according to a fifth embodiment of the present invention.

FIG. 10

is a side elevation illustrating an impeller according to a sixth embodiment of the present invention.

FIG. 11

is a side elevation illustrating the neighborhood of a wheel portion according to a seventh embodiment of the present invention.

FIG. 12

is a side elevation illustrating the neighborhood of a wheel portion according to an eighth embodiment of the present invention.

FIG. 13

is a cross sectional view illustrating the neighborhood of a pulley mechanism according to a ninth embodiment of the present invention.

FIG. 14

is a cross sectional side view illustrating a pulley mechanism according to a tenth embodiment of the present invention.

FIG. 15

is a cross sectional side view illustrating a pulley mechanism according to an eleventh embodiment of the present invention.

FIG. 16

is a cross sectional view taken along line G—G in FIG.

15

.

FIG. 17

is a cross sectional side view illustrating a twelfth embodiment of the present invention.

FIG. 18

is a perspective view schematically illustrating essential portions of a once-through pump according to a twelfth embodiment of the present invention.

FIG. 19

is a side elevation illustrating, on an enlarged scale, a fluid inflow section according to a thirteenth embodiment of the present invention.

FIG. 20

is a side elevation illustrating, on an enlarged scale, a fluid discharge section according to the thirteenth embodiment of the present invention.

FIG. 21

is a side elevation illustrating a linear vane array according to a fourteenth embodiment of the present invention.

FIG. 22

is a side elevation illustrating a centrifugal vane array according to the fourteenth embodiment of the present invention.

FIG. 23

is a cross sectional side view illustrating a fifteenth embodiment of the present invention.

FIG. 24

is a cross sectional side view illustrating, on an enlarged scale, once-through pump (once-through blower) according to the fifteenth embodiment of the present invention.

FIG. 25

is a cross sectional side view illustrating a known once-through pump (once-through blower).

FIG. 26

is an enlarged cross sectional view illustrating the operation of fluid F in the vicinity of an impeller in FIG.

25

.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings while taking an example of a once-through blower as in the above-mentioned known one.

Embodiment 1

FIG. 1

is a cross sectional side view illustrating a first embodiment of the present invention. In this figure, the same or corresponding parts or elements as those in the aforementioned known example described with reference to FIG.

25

and

FIG. 26

are identified by the same symbols while omitting a detailed description thereof.

In

FIG. 1

, an impeller, generally designated at 10, is provided on the outer periphery thereof with a plurality of vanes

11

, and it is disposed in and rotatably supported through a rotation shaft

20

in a flow passage P such as a channel, duct or the like so that it is driven to rotate in a direction of arrow B around the rotation shaft

20

.

The impeller

10

has a substantially D-shaped cross section including a straight portion

10

a

formed on its suction or inlet side for fluid F, and an arc portion

10

b

formed on its discharge or outlet side for fluid F.

Also, the impeller

10

is formed on its outer periphery with a plurality of vanes

11

, each of which has a positive vane angle with respect to the advancing direction (see arrow A) in the straight portion

10

a.

FIG. 2

is a perspective view illustrating, on an enlarged scale, essential portions of a once-through blower according to the first embodiment of the present invention.

In

FIG. 2

, the impeller

10

has a plurality of connecting portions

21

connected at their one ends with the rotation shaft

20

, a wheel portion

22

connected with the other ends of the connecting portions

21

, and an unillustrated straight portion forming means to be described later.

The rotation shaft

20

of the impeller

10

has its one end extending through a side plate

23

so as to project outside, so that the output shaft of a motor M is coupled with the outwardly projected end of the rotation shaft

20

for driving the impeller

10

to rotate.

The side plate

23

is arranged to cover an entire side portion of the blower, thereby preventing backflow of the fluid F from the blower side portion.

The connecting portions

21

are each made of a flexible member such as, for example, a wire-like member, and serve to connect the wheel portion

22

with the rotation shaft

20

of the impeller

10

.

The wheel portion

22

is made of an elastic material such as silicon rubber and it is arranged in a curvable or flexible manner on the outer peripheral portion of the impeller

22

at each of the sides thereof.

The straight portion forming means forms the straight portion

10

a

in a part of the wheel portion

22

.

FIG. 3

is a perspective view illustrating a concrete example of the straight portion forming means according to the first embodiment of the present invention.

In

FIG. 3

, a pulley-shaped guide roller

24

is fixedly secured to the side plate

23

thereby to constitute the straight portion forming means for providing the straight portion

10

a

to the wheel portion

22

.

The guide roller

24

serves to guide a part of the wheel portion

22

from the outside thereof to forcedly position it in place, thus forming the straight portion

10

a.

FIG.

4

A and

FIG. 4B

are side views illustrating the straight portion

10

a

and the arc portion

10

b

, respectively, according to the first embodiment of the present invention.

In FIG.

4

A and

FIG. 4B

, each of the vanes

11

is formed at its radially outer end with a support shaft

11

a

, so that it is inserted into and fixedly secured to the wheel portion

22

through the support shaft

11

a.

In addition, each of the vanes

11

has a positive vane angle θ with respect to an advancing direction A at the arc portion

10

b

, and to a rotational direction B at the straight portion

10

a.

Here, note that each pair of support shafts

11

a

are made of resin and integrally formed with and molded to the opposite sides of a corresponding vane

11

.

Moreover, the wheel portion

22

is provided with a plurality of openings

22

a

at locations corresponding to the support shafts

11

a.

The respective vanes

11

are fixed to the wheel portion

22

by inserting and fixing the support shafts

11

a

into and to the corresponding openings

22

a

in the wheel portion

22

.

FIG.

5

A and

FIG. 5B

are explanatory views illustrating velocity triangles (i.e., vector diagrams) in the straight portion

10

a

and in the arc portion

10

b

, respectively, according to the vane angle θ of each vane

11

.

In

FIG. 5A

, an average relative speed w∞ is an average value of a relative speed w

1

at the suction or inlet side of the impeller

10

and an average relative speed w

2

at the discharge or outlet side thereof. Additionally, an angle α is an actual angle of attack with respect to the fluid F.

Hereinafter, reference will be made to a concrete air-blowing operation according to the first embodiment of the present invention while referring to FIG.

1

through FIG.

4

and FIG.

5

A and FIG.

5

B.

In the once-through blower according to the first embodiment of the present invention, basically, rotational centrosymmetry of the impeller

10

is partially broken to provide a D-shaped cross sectional configuration, as shown in FIG.

1

.

With such a configuration, in the straight portion

10

a

, a force is applied to the fluid F in a direction from the right to the left in

FIG. 1

by means of a straight or linear array of vanes, and in the arc portion

10

b

, a centrifugal force is further applied to the fluid F, thereby ensuring that the fluid F can be caused to flow from the left to the right.

At this time, in the straight portion

10

a

, it is possible to raise the pressure of the fluid F by about 9 mmAq (90 Pa), though somewhat varied depending on the conditions given.

In addition, in the arc portion

10

b

, it is possible to obtain a pressure increase of about 18 mmAq (180 Pa) in cases where the diameter of the arc portion

10

b

is particularly large so as to generate a large centrifugal force.

Accordingly, by using the D-shaped configuration as depicted in

FIG. 1

, it is possible to obtain a pressure rise of the fluid F of about 27 mmAq (270 Pa) in total.

Besides, the structure in the axial direction of the impeller

10

can arbitrarily be extended so as to adapt the blower to an optional amount of blast or flow rate as required.

Thus, a sufficient amount of blast or flow rate as required can be provided even in case of a bad condition (e.g., in a limited space available for installation with a high flow resistance of the flow passage P).

Concretely, the wheel portion

22

made of silicon rubber (see FIG.

2

through

FIG. 4

) is connected with the rotation shaft

20

through the flexible connecting portions

21

, and the guide roller

24

(see

FIG. 3

) is pressed against a part of the wheel portion

22

so as to achieve a D-shaped cross sectional configuration.

Therefore, a part of the impeller

10

is compulsorily crushed by the guide roller

24

to form the straight portion

10

a

, whereby the vanes

11

carry out linear motion.

Z(=from 20 to 60) pieces of vanes

11

each have a vane angle θ (=form 10° to 45°) for instance in a forward direction with respect to the advancing direction A and the rotational direction B, and are arranged at equal or unequal intervals.

Moreover, the vanes

11

support about the half of vane camber (or an inner side portion from the half) to the support shafts

11

a

, as illustrated in

FIG. 4

, and they are normally fixed to the wheel portion

22

against rotation relative thereto.

As a result, the vanes

11

advance while holding the vane angle θ in the advancing direction, so they are subjected to an application force without any centrifugal force.

At this time, the amount of pressure rise ΔPt of the fluid F due to passage thereof through the impeller

10

is expressed by the following equation (1) based on Bernoulli's theorem (Bernoulli law).

Δ

Pt

=(½)ρ(

w

1

2

−w

2

2

)+(½)ρ(

c

2

2

−c

1

2

) (1)

where ρ represent the density of the fluid F; w represents the speed of the fluid F relative to the vanes

11

; c represents the absolute velocity of the fluid F; w

1

represents the initial speed of the fluid F relative to the vanes

11

; c

1

represents the absolute initial velocity of the fluid F; w

2

represents the speed of the fluid F relative to the vanes

11

after the fluid F has passed the vanes

11

(i.e., after the lapse of a time); c

2

represents the absolute velocity of the fluid F after the fluid F has passed the vanes

11

(i.e., after the lapse of a time) (see the velocity triangles in FIG.

5

A and FIG.

5

B).

In equation (1) above, the first term on the right side of the equal sign represents the amount of static pressure rise due to a decrease in the speed w of the fluid F relative to the impeller

10

, and the second term on the same side represents the amount of dynamic pressure rise due to an increase in the absolute velocity c of the fluid F according to the rotational force of the impeller

10

.

Here, a part of dynamic pressure is converted into a static pressure in the space inside the impeller

10

, the most part of which achieves a static pressure rise enough to increase the pressure by about 9 mmAq to the right-hand side in the straight portion

10

a.

In addition, the impeller

10

, which rotates together with the rotation shaft

20

through the connecting portions

21

, functions substantially as a centrifugal blower to raise the pressure of the fluid F in the blowing direction while applying a forward force to the fluid F.

At this time, the impeller

10

functions as a booster, and the amount of pressure ΔPt′ of the fluid F is expressed by the following equation (2).

Δ

Pt

′=(½)ρ(

u

2

′

2

−u

1

′

2

)+(½)ρ(

w

1

′

2

−w

2

′

2

)+(½)ρ(

c

2

′

2

−c

1

′

2

) (2)

where u represent the rotational speed of the impeller

10

; u

1

′ represents the initial rotating speed of the impeller

10

; and u

2

′ represents the rotating speed of the impeller

10

after passage of the fluid (after the lapse of a time).

Moreover, in equation (2) above, the third term on the right side of the equal sign is the part of a dynamic pressure rise, and occupies more than one-half of the force applied by the rotation shaft

20

in cases where the vanes

11

comprise forwardly directed vanes of a short cord length.

Thus, it is possible to realize a static pressure rise of about 18 mmAq by recovering the rise of the dynamic pressure in the third term into a static pressure in an expanding or divergent duct portion which expands or diverges gradually while turning at the downstream side of the blower.

As a result, owing to the pressure rise in equation (2) above in combination with the pressure rise in equation (1) above, the total pressure of the fluid F can be raised by 27 mmAq or so.

In this manner, since the fluid F (air stream) can be pressurized twice by means of the array of vanes

11

arranged in the generally D-shaped configuration, the final pressure rise becomes greater in this embodiment than in the case of axial-flow blowers or the aforementioned known once-through blower (see FIG.

25

and

FIG. 26

) with a flow passage of the same diameter.

In addition, in the case of the once-through blower in which an arbitrary depth space can be set in the axial direction as previously described, there is no limitation on the amount of blast or flow rate.

Moreover, the fluid F is curved or bent in its flowing or advancing direction in the straight portion

10

a

of the impeller

10

, but after having passed the straight portion

10

a

, it is dispersed in the following portion of the impeller

10

to reduce its absolute velocities c

2

m, C

2

so that it enters the arc portion

10

b

at the absolute velocities of c

1

m′ and c

1

′ (see FIG.

5

A and FIG.

5

B).

This means that in case of the once-through blower, the fluid F flows into the arc portion

10

b

while having a turning component in advance, and hence this is a somewhat severe inflow state for the vanes

11

.

However, like the velocity triangle illustrated in FIG.

5

A and

FIG. 5B

, the fluid F in the arc portion

10

b

is pressurized in a downward direction in these figures so that the blower acts as a contrarotating blower to recover the bending speed, thus achieving high efficiency.

It is more effective if provision is made for stationary vanes (not shown) between the straight portion

10

a

and the arc portion

10

b

for recovering an advancing direction component (pre-turning component to the later-stage arc portion

10

b

) of the fluid F which exits from the straight portion

10

a.

On the other hand, when considering the sound generated during rotation of the impeller

10

, it is not necessary for the once-through blower according to the first embodiment of the present invention (FIG.

1

through

FIG. 5

) to adopt the flow channel or duct structure of the aforementioned known once-through blower (see FIG.

25

and FIG.

26

)(i.e., the markedly asymmetric bent or turned configuration provided by the tongue portion

2

), and hence the bending or turning angle of the flow passage or duct in this embodiment can be made much more gradual than in the known case, thus making it possible to reduce resultant noise to a considerable extent.

Particularly, in the case of the once-through blower according to the first embodiment of the present invention, the fluid F applied by the turning force forms a large swirl or vortex localized near the rotation shaft

20

, which, however, is generated at a location away from the vane array unlike the swirl or vortex E generated in the aforementioned known once-through blower (see FIG.

26

), so interference sounds of the fluid F with the vane arrays can be reduced to a substantial extent, thereby suppressing resultant noise in an effective manner.

Moreover, the connection between the wire-like connecting portions

21

and the rotation shaft (drive shaft)

20

is effected, for instance, by fixing the connecting portions

21

to a drive shaft disk (not shown) of the rotation shaft

20

.

At this time, the connection point between the connecting portions

21

and the rotation shaft

20

may be constructed to allow relative rotation with respect to each other, thereby making it possible to prevent deformation stress from being concentrated on the drive end of the rotation shaft

20

.

Embodiment 2

In the above-mentioned first embodiment, the support shafts

11

a

integrally formed with the vanes

11

are used in the fixing structure for fixing the vanes

11

to the impeller

22

, but they may be constituted by vanes

11

and support rods

12

which are formed separately from each other, made of different materials (for example, the vanes

11

are made of a resin and the support rods are made of a metal) and then assembled together into an integral unit.

FIG. 6

is a side elevation illustrating a curved portion between the straight portion

10

a

and the arc portion

10

b

according to a second embodiment of the present invention.

In

FIG. 6

, the structure in a circumferential direction of the wheel portion

22

is formed into a uniform belt-shaped configuration so as to enclose openings

22

a

(see

FIG. 7

) corresponding to the support rods

12

, but it is formed with notches

22

b

which serve to facilitate the deformation thereof into the straight portion

10

a

and the arc portion

10

b

, and the intervals between the support portions of the respective vanes

11

are set to be as narrow as possible.

The circumferential portion of the wheel portion

22

may have an increased thickness for the purpose of preventing swing or oscillating motions, as in the aforementioned first embodiment.

The vanes

11

thus fixed to the wheel portion

22

are caused to rotate by means of the rotating force of the rotation shaft

20

through the connecting portions

21

, as illustrated in FIG.

6

.

At this time, the connecting portions

21

, being of the wire-like configuration and having a limited amount of expansion, limits the movement of the wheel portion

22

in a radial direction thereof in the arc portion

10

b

as in the above-mentioned first embodiment, whereas they are easily deformable in a compressive direction, thereby permitting free compressive deformation of the wheel portion

22

in the straight portion

10

a.

In addition, the wire-like connecting portions

21

may be made of an elastic material.

Embodiment 3

Although in the above-mentioned first and second embodiments, the connecting portions

21

are formed into the wire-like configuration, they may be formed into a plate-like configuration.

FIG.

7

A and

FIG. 7B

are perspective views illustrating the connecting portions

21

constructed in a plate-like configuration according to a third embodiment of the present invention, wherein

FIG. 7

a

shows the case in which notches

21

b

are formed on a curved surface, and

FIG. 7

b

shows the case in which a continuous bracelet structure is provided on a curved surface.

In

FIG. 7

a

, the tip end of each support rod

12

is inserted into and fixedly attached to a corresponding opening

22

a

in the wheel portion

22

.

For instance, the tip end of each support rod

12

is engaged with the corresponding opening

22

a

in the wheel portion

22

against rotation relative thereto.

Also, each support rod

12

is formed at its tip with a notch, bent portion or the like as necessary so as to prevent any displacement thereof relative to the wheel portion

22

. In addition, the tip end of each support rod

12

is melted in and sealed with the corresponding opening

22

a

so that it is securely fixed to the wheel portion

22

.

Moreover, the wheel portion

22

is required to have a thickness more than a certain level or value in order to prevent oscillations in a thrust direction and hold an arc-shaped configuration in the circumferential direction, so the axial thickness of the wheel portion

22

is properly set according to the modulus of elasticity of a material (e.g., silicon rubber, etc.) used, the diameter of the wheel portion

22

and so on.

Providing an arbitrary number of notches

21

b

at a location between the opposite ends of each connecting portion

21

, as depicted in

FIG. 7A

, serves to permit the connecting portions

21

to be deformed in an arbitrary direction such as, for example, in a radially inner direction, in an advancing direction, etc.

The notches

21

b

can be formed on at least one of the outer peripheral side and the inner peripheral side of the curved surfaces of the connecting portions

21

.

Moreover, in

FIG. 7A

, the connecting portions

21

have the openings

21

a

corresponding to the openings

22

a

in the wheel portion

22

, respectively, and are fixed to the wheel portion

22

through the support rods

12

.

Similarly, in

FIG. 7B

, the connecting portions

21

, being of the bracelet structure, can be deflected or curved in an arbitrary direction.

Further, in

FIG. 7B

, each connecting portion

21

has an engagement rod

21

c

corresponding to another opening

22

c

in the wheel portion

22

, so that it is fixed to the wheel portion

22

by being inserted into the corresponding opening

22

c.

In addition, in FIG.

7

A and

FIG. 7B

, the connecting portions

21

may be constituted by resin plates.

Since the connecting portions

21

each formed into the plate-like configuration as shown in FIG.

7

A and

FIG. 7B

have a sufficient thickness in the thrust direction, thrust oscillations of the wheel portion

22

can be made to a minimum.

Moreover, providing one or more notches

21

b

, as shown in

FIG. 7A

, serves to facilitate the compressive deformation in the rotational direction of the connecting portions

21

.

That is, the connecting portions

21

can be compressively deformed easily in one (forward or rearward) direction under the action of the notches

21

b.

Therefore, it is possible to avoid mutual interference between the connecting portions

21

.

Embodiment 4

Although in the above-mentioned third embodiment, the plate-like connecting portions

21

are constructed such that they can be deflected or curved in the rotational direction thereof, they may instead be constructed so as to be deflected or curved in the direction of thrust.

FIG. 8

is a cross sectional view illustrating connecting portions

21

, which can be deflected or curved in the thrust direction, according to a fourth embodiment of the present invention.

In

FIG. 8

, the direction in which the connecting portions

21

are deformed to curve is set to be in the radially inward direction of the side plates

23

, so there will be no interference of the connecting portions

21

with the side plates

23

.

Moreover, the direction in which the connecting portions

21

are deformed to curve or bend can be arbitrarily set depending on an angle formed by the notches

21

b

, so that the connecting portions

21

can be curved or bent substantially perpendicularly toward the inside of the impeller

10

.

Concretely, the curving or bending direction of the connecting portions

21

is set inwardly of the once-through blower in relation to the arrangement of the side plates

23

of the once-through blower.

According to the construction of

FIG. 8

, mutual interference between the connecting portions

21

can surely be avoided.

Moreover, in the arrangement of

FIG. 8

, similar to the aforementioned embodiments, the connections between the connecting portions

21

and the rotation shaft

20

can be made by fixing the connecting portions

21

to an unillustrated drive shaft disk of the rotation shaft

20

. Thus, the connection point between the connecting portions

21

and the rotation shaft

20

may be constructed to allow relative rotation with respect to each other, thereby making it possible to suppress concentration of deformation stress on the drive end of the rotation shaft

20

.

Embodiment 5

Although in the above-mentioned first and second embodiments, the wire-like connecting portions

21

are each fixed to the rotation shaft

20

and the wheel portion

22

, respectively, at one point for each of them, such connections may be made in an X-shaped or crossed fashion at a plurality of points for each connection.

FIG. 9

is a side elevation illustrating connecting portions

21

, which are formed in an X-shaped or crossed fashion, according to a fifth embodiment of the present invention.

In

FIG. 9

, each of the wire-like connecting portions

21

has a three-point connection structure including one connection point with respect to the wheel portion

22

and two connection points with respect to the rotation shaft

20

.

The construction of

FIG. 9

serves to strengthen the connection structure for connecting between the wheel portion

22

and the rotation shaft

20

through the connecting portions

21

, so that high transmission efficiency for the rotational force and minimization of fluctuations in rotation of the once-through blower can be achieved at the same time.

Embodiment 6

Although in the above-mentioned first embodiment, the wheel portion

22

is formed into the completely D-shaped configuration, it may be formed on the straight portion with an outwardly projected bend portion, as shown in FIG.

10

.

FIG. 10

is a side elevation illustrating an impeller

10

with a bend portion

10

c

formed in its straight portion according to a sixth embodiment of the present invention.

In

FIG. 10

, the wheel portion

22

has the bend portion

10

c

in the straight portion, which includes two straight sections

10

a

1

and

10

a

2

.

The wheel portion

22

is basically formed into a generally D-shaped configuration as described above, but in cases where the area in the straight portion is far less than that in the arc portion

10

b

, the bend portion

10

c

is provided to the straight portion, as shown in FIG.

10

.

With this provision, there is formed a curved or bent configuration enclosed by the two straight sections

10

a

1

and

10

a

2

, so that a sufficient area can be ensured in the straight portion, thus permitting an enough amount of fluid F to be thereby drawn.

Embodiment 7

Although in the above-mentioned first embodiment, the guide roller

24

is used as a straight portion forming means for forming the wheel portion

22

into a D-shaped configuration, a D-shaped guide plate member

25

may be used for the same purpose, as shown in FIG.

11

.

FIG. 11

is a side elevation illustrating the surroundings of a wheel portion

22

using the guide plate member

25

as the straight portion forming means according to a seventh embodiment of the present invention, in which an impeller

10

is partially illustrated on an enlarged scale so as to avoid complexity.

In

FIG. 11

, the guide plate member

25

formed of an iron plate for instance is arranged inside the wheel portion

22

, and it is formed into a D-shaped configuration having a straight portion

10

a

and an arc portion

10

b.

The straight portion

10

a

of the guide plate member

25

may be provided with the above-mentioned bend portion

10

c

(see FIG.

10

).

The wheel portion

22

is constituted by a chain member

22

a

which is slidable along the outer periphery of the guide plate member

25

, the chain member being adapted to be driven to rotate by means of a motor (not shown) through a drive shaft

26

which is in engagement with the chain member.

The wheel

22

in the form of the chain member has teeth

22

d

to which vanes

11

and support rods are fixedly secured against rotation, so that the wheel portion

22

is caused to slide on the guide plate member

25

, thereby generating a stream of air.

In this case, in order to minimize a mechanical friction loss as well as noise generated, there is interposed lubricating oil between the wheel portion

22

in the form of the chain member and the guide plate member

25

formed of an iron plate.

Moreover, the contact portions of the wheel portion

22

and the guide plate member

25

are made of combinations of materials with a limited coefficient of friction such as Teflon, so as to be smoothly slidable with respect to each other to a sufficient extent.

In addition, the output shaft of the unillustrated motor is operatively connected through the drive shaft

26

with the wheel portion

22

in the form of a gear, so that it can drive the wheel portion

22

through the drive shaft

26

.

Here, note that the output shaft of the motor may be provided with receiving or engagement teeth which is directly engageable with the teeth

22

d

of the wheel portion

22

, and in this case, the motor can directly drive the wheel portion

22

without using the drive shaft

26

.

When the guide plate member

25

is used as shown in

FIG. 11

, it becomes unnecessary to employ the pressing guide roller

24

(see

FIG. 3

) for forming the straight portion

10

a.

Further, the wheel portion

22

slides directly on the guide plate member

25

, and hence the connecting portions

21

as described above become unnecessary, too.

Embodiment 8

Although in the above-mentioned first embodiment, the single guide roller

24

is provided as the straight portion forming means, a plurality of guide rollers

24

may be arranged in parallel with one another, as shown in FIG.

12

.

FIG. 12

is a side elevation illustrating the surroundings of a wheel portion

22

using the plurality of guide rollers

24

according to an eighth embodiment of the present invention, in which an impeller

10

is partially illustrated on an enlarged scale so as to avoid complexity.

In

FIG. 12

, the plurality of guide rollers

24

are arranged along a straight portion

10

a

of the impeller

10

.

With this arrangement, the pressing function of the guide rollers

24

can be achieved in a more reliable manner.

Here, note that if the surface of each guide roller

24

is provided with irregularities (convexes and concaves) for decreasing the area of contact thereof with the wheel portion

22

in addition to the use of the guide members with limited sliding frictions, it is possible to further improve the sliding effect.

Embodiment 9

Although in the above-mentioned first embodiment, the guide roller

24

is used as the straight portion forming means, a pulley mechanism

27

formed integral with a wheel portion

22

may instead be employed, as shown in FIG.

13

.

FIG. 13

is a cross sectional view illustrating the surroundings of the pulley mechanism

27

according to a ninth embodiment of the present invention.

In

FIG. 13

, the pulley mechanism

27

is provided on one end of the wheel portion

22

.

The pulley mechanism

27

comprises a roller

27

a

rotatably mounted on the wheel portion

22

, and a guide rail

27

b

for guiding the roller

27

a.

In this case, the guide rail

27

b

is formed into a D-shaped configuraion with a U-shaped cross section.

In addition, the wheel portion

22

serves to position and fix vanes

11

through support rods

12

, thus holding a predetermined vane angle of the vanes

11

.

Here, note that the wheel portion

22

may be driven by the above-mentioned connecting portions

21

.

Thus, with the arrangement in which the comparatively small pulley mechanism (guide roller mechanism)

27

is incorporated in or provided at one end of the wheel portion

22

to permit the roller

27

a

to be rolled within the guide rail

27

b

, as shown in

FIG. 13

, it is possible to further reduce a driving loss of the wheel portion

22

.

Moreover, by using the guide rail

27

b

of the pulley mechanism

27

, the wheel portion

22

can be driven to move under the guidance of the guide rail

27

b

without the necessity of aligning the rotation shaft

20

(see

FIG. 1

) with the drive shaft, as in the case of using the guide plate member

25

and the chain member (see FIG.

1

).

Embodiment 10

Although in the above-mentioned ninth embodiment, the roller

27

a

is rotated within the guide rail

27

b

, the pulley mechanism

27

may have a roller portion

27

c

which is slidable within the guide rail

27

b

, as shown in FIG.

14

.

FIG. 14

is a cross sectional side view illustrating a pulley mechanism

27

having the roller portion

27

c

slidable within the guide rail

27

b

according to a tenth embodiment of the present invention.

In

FIG. 14

, the roller portion

27

c

is arranged to slide within the guide rail

27

b

of the pulley mechanism

27

.

The roller portion

27

c

has protrusions

27

d

for reducing the contact area thereof with the guide rail

27

b.

In this case, the wheel portion

22

can be driven to move by the above-mentioned connecting portions

21

.

In

FIG. 14

, the wheel portion

22

has limited elasticity and merely functions as a spacer for holding appropriate intervals between the adjacent ones of the vanes

11

. The wheel portion

22

is slidable within the D-shaped guide rail

27

b

through the roller portion

27

c

in the form of rod-like protrusions provided at one end of the wheel portion

22

.

In this case, too, as previously stated, it is possible to reduce a slipping loss by providing irregularities (e.g., convexes and concaves) on the contact surfaces of the guide rail

27

b

and the roller portion

27

c.

Here, note that the roller portion

27

c

need not be provided on the wheel portion

22

but may instead be installed on the wire-like or plate-like connecting portions

21

.

According to the pulley mechanism

27

shown in

FIG. 14

, it is possible to construct the guide rail

27

b

in a small size to thereby make the impeller

10

compact and small-sized as a whole, though driving resistance becomes larger to a slight extent.

Embodiment 11

Although in the above-mentioned tenth embodiment, the roller portion

27

c

is slidable within the guide rail

27

b

, there may instead be used a corrugated plate spring

27

e

which is slidable within the guide rail

27

b

, as illustrated in FIG.

15

and FIG.

16

.

FIG. 15

is a cross sectional side view illustrating a pulley mechanism

27

using a corrugated plate spring

27

e

slidable within the guide rail

27

b

according to an eleventh embodiment of the present invention.

FIG. 16

is a cross sectional view taken on line G—G in FIG.

15

.

In FIG.

15

and

FIG. 16

, the corrugated plate spring

27

e

is arranged so as to slide on the guide rail

27

b

in place of the above-mentioned roller portion

27

c

(see FIG.

14

).

In this case, the corrugated plate spring

27

e

also functions as the above-mentioned wheel portion

22

, so the wheel portion

22

becomes unnecessary.

Embodiment 12

Although in the above-mentioned first embodiment, the impeller has a D-shaped cross section, it is formed into such a D-shaped configuration using a belt-like connecting portion associated with a drive shaft.

FIG. 17

is a cross sectional side view illustrating an impeller using a belt-like connecting portion according to a twelfth embodiment of the present invention, in which the same or like components as those in the aforementioned embodiments are identified by the same symbols while omitting a detailed description thereof.

FIG. 18

is a perspective view schematically illustrating the three-dimensional structure of a once-through blower according to the twelfth embodiment of the present invention.

In

FIG. 17

, an impeller

10

arranged in the flow passage P is driven to rotate in a direction indicated at arrow B around an axis of rotation oriented in a diametrical direction of the flow passage P.

In addition, the impeller

10

is provided on the outer periphery thereof with a plurality of vanes

11

(vane array) arranged at equal intervals.

The impeller

10

has a generally D-shaped cross sectional configuration including a straight portion

10

a

formed on a fluid inlet or suction side Fa and an arc portion

10

b

formed on a fluid outlet or discharge side Fb.

Moreover, the respective vanes

11

(arrayed vanes) forms a linear vane array in the straight portion

10

a

and an arc-shaped centrifugal vane array in the arc portion

10

b.

A pair of partitions PA are protrudingly formed in the flow passage P in such a manner as to clamp the impeller

10

from the opposite sides thereof in a diametrical direction thereof.

The impeller

10

includes a drive shaft

20

, at least one (e.g., two in the example illustrated in FIG.

17

and

FIG. 18

) belt-like connection portion

30

for connecting and arranging the arrayed respective vanes

11

with one another at substantially equal intervals, at least one (e.g., two in the example illustrated in FIG.

17

and

FIG. 18

) large wheel

40

for supporting the at least one belt-like connecting portion

30

from its inside, and at least one (e.g., four in the example illustrated in FIG.

17

and

FIG. 18

) small wheel

50

arranged at a location(s) apart from and opposite to the at least one large wheel

40

for supporting the at least one belt-like connecting portion

30

from its inside.

In

FIG. 18

, the drive shaft

20

is coupled with the rotation shaft of the motor M, so that the drive shaft

20

is driven to rotate by means of the motor M, thereby rotating the impeller

10

through two small wheels

50

connected with the drive shaft

20

together with two other small wheels

20

and two large wheels

40

while supporting two belt-like connecting portions

30

from their inside by means of these wheels

40

,

50

.

The array of vanes

11

(vane array) integrally arranged on the outer peripheries of the belt-like connecting portions

30

are urged into pressure contact with the outer peripheries of the large wheels

40

while being pulled by the drive shaft

20

through the small wheels

50

. As a result, a linear array of vanes and a centrifugal array of vanes are compulsorily formed in the straight portion

10

a

and in the arc portion

10

b

, respectively.

That is, the small wheels

50

contribute to the formation of the linear vane array on the fluid inlet or suction side of the impeller

10

, whereas the large wheels

40

contribute to the formation of the centrifugal vane array on the fluid outlet or discharge side of the impeller

10

.

In this case, since the belt-like connecting portion

30

having the vanes

11

is compulsorily deformed to form a generally D-shaped cross sectional configuration, it is necessary to have two mutually contradictory functions, one being the easiness for the outer shape of the straight portion

10

a

(linear vane array) to collapse, the other being an elastic shape holding capability of holding the elastic outer shape of the arc portion

10

b

(arc-shaped centrifugal vane array).

Moreover, it is required that the part of each belt-like connecting portion

30

to which a rotational driving force (basically, pulling force) is transmitted from the drive shaft

20

has an elasticity just enough to withstand collapsing of the outer shape.

In view of these conditions, it has been experimentally determined that a belt mechanism comprising a combination of the belt-like connecting portions

30

, the large wheels

40

and the small wheels

50

, as depicted in FIG.

17

and

FIG. 18

, is the best solution.

Now, reference will be made to the air-blowing operation according to the twelfth embodiment of the present invention as illustrated in FIG.

17

and FIG.

18

.

In the case of the centrifugal blower illustrated in

FIG. 17

, the space in the flow passage P between the straight portion

10

a

(inlet or suction side) pulled by the small wheels

50

and the semicircular arc portions

10

b

(outlet or discharge side) is separated and closed up by the pair of partitions PA protruded inwardly from the upper and lower walls of the flow passage P in FIG.

17

.

Thus, the fluid (air stream) is sucked or drawn into the impeller

10

while being somewhat dragged in the rotational direction B in the linear vane array of the straight portion

10

a

shown to the right in

FIG. 17

, as indicated therein by an inlet or suction flow Fa.

Subsequently, in the centrifugal vane array of the arc portion

10

b

shown to the left in

FIG. 17

, the fluid F is discharged from the impeller

10

while similarly being somewhat dragged in the rotational direction B with a centrifugal force being applied thereto as indicated by an outlet or discharge flow Fb.

At this time, the fluids Fa and Fb are subjected to pressurization at two stages in the straight portion

10

a

and the arc portion

10

b

, whereby a pressure rise equal to or more than that with a centrifugal blower can be obtained unlike ordinary once-through blowers.

Moreover, the impeller

10

can be axially extended infinitely as long as the layout in the design permits, so that a desired amount of blast or flow rate can be obtained.

In addition, since the fluids Fa and Fb are pressurized while being dragged in the rotational direction B, as described above, if an outlet or discharge opening is directed in the rotational direction to a some extent in the arc portion

10

b

(centrifugal vane array) for example, the discharge flow Fb can be discharged or exited without any loss.

Embodiment 13

Although in the above-mentioned twelfth embodiment, any special consideration is not given to the suction opening and the discharge opening for the fluids Fa and Fb, respectively, stationary vanes may be provided in association with the linear vane array and the centrifugal vane array for offsetting a velocity component in the rotational direction B.

FIG.

19

and

FIG. 20

are enlarged side elevations illustrating a vane array portion equipped with stationary vanes according to a thirteenth embodiment of the present invention.

In

FIG. 19

, a plurality of inlet stationary vanes

12

and a plurality of intermediate stationary vanes

13

are arranged on the upstream side and the downstream side, respectively, of the straight portion

10

a

(linear vane array).

Also, in

FIG. 20

, a plurality of outlet stationary vanes

14

are arranged on the downstream side of the arc portion

10

b

(centrifugal vane array) in FIG.

20

.

First of all, in

FIG. 19

, the inlet stationary vanes

12

located on the upstream side of the straight portion

10

a

(linear vane array) creates a prewhirl to the suction flow Fa, which is immediately before entering the impeller

10

, in a direction opposite the rotational direction B, as indicated by a broken line arrow, thereby offsetting the flow in the rotational direction.

Subsequently, the intermediate stationary vanes

13

in the impeller

10

recovers a rotational direction component of the fluid which has passed the vanes

11

of the linear array and flowed into the impeller

10

, and creates a prewhirl to the centrifugal vane array in the delivery portion, as indicated by a broken line arrow.

Further, in

FIG. 20

, the outlet stationary vanes

14

located on the downstream side of the centrifugal vane array recovers a velocity component generated in the rotational direction B of the discharge flow Fb, as indicated by a broken line arrow in

FIG. 20

, thereby increasing the static pressure of the fluid which has been just discharged from the impeller

10

past the vanes

11

in the arc portion

10

b

(centrifugal vane array).

In this manner, the proper arrangement of the stationary vanes

12

through

14

serves to further improve stability in operation of the once-through blower and achieve a very large increase in pressure and the amount of air flow as well as reduction in noise.

Moreover, the rotating speed of the impeller

10

can be greatly raised, thereby further increasing the air-blowing efficiency and the blast pressure.

However, since there will be generated interference noise if the array of rotating vanes

11

and the stationary vanes

12

through

14

are located too close to each other, it is necessary to keep proper intervals or distances between the array of vanes

11

and the stationary vanes

12

through

14

.

Embodiment 14

Although in the above-mentioned twelfth embodiment, the detailed structure of the belt-like connecting portions

30

has not been referred to, a toothed belt may be used for each belt-like connecting portion

30

, as illustrated in FIG.

21

and FIG.

22

.

Moreover, the large wheels

40

may have the function of the drive shaft

20

.

Generally, the main body of each belt-like connecting portion

30

may be an ordinary V belt or flat belt, but it is preferable to use a toothed belt in order to drive the axially elongated impeller

10

(see

FIG. 18

) without distorting it at its opposite ends.

The reason for this is as follows. That is, in case of the known once-through blower (see FIG.

25

), the impeller

10

is integrally formed of a resin, and hence there is substantially no or little possibility of deformation and the above condition is irrelevant. However, in case of a belt type once-through blower as in the present invention (see FIG.

17

and FIG.

18

), if there takes place no good synchronization in driving timing at the opposite axial ends of the impeller

10

and hence the belt-like connecting portions

30

(that is, non-synchronization of the large and small wheels

40

,

50

at the opposite axial ends of the impeller

10

), the impeller

10

would be caused to vibrate, and hence distortion of the impeller

10

at the opposite ends thereof must be suppressed by the use of the toothed belts.

Hereinafter, a once-through blower using a pair of toothed belts according to a fourteenth embodiment of the present invention will be described in detail while referring to FIG.

21

and FIG.

22

.

FIG.

21

and

FIG. 22

are enlarged side elevations illustrating a vane array part of a belt-like connecting portion according to the fourteenth embodiment of the present invention.

In FIG.

21

and

FIG. 22

, each belt-like connecting portion

30

has a plurality of outer periphery support sections

31

arranged at equal intervals along the rotational direction B of the impeller

10

.

The respective vanes

11

(vane array) of the impeller

10

are fixed to the outer periphery support sections

31

of each belt-like connecting portion

30

, and they are each arranged to maintain a constant vane angle θ.

In addition, each belt-like connecting portion

30

is formed on the inner peripheral side thereof with inner peripheral teeth

32

which are arranged at equal intervals along the rotational direction B of the impeller

10

.

The inner peripheral teeth

32

are formed with the same pitch as that of the outer periphery support sections

31

, and forms an integral quadrilateral together with the outer periphery support sections

31

.

On the other hand, each of the large wheels

40

includes a plurality of outer peripheral teeth

42

arranged at equal intervals along the rotational direction B, as shown in FIG.

22

.

As illustrated, the outer peripheral teeth

42

of each large wheel

40

are formed so as to be engageable with the inner peripheral teeth

32

of the corresponding belt-like connecting portion

30

.

The outer peripheral teeth

42

and the inner peripheral teeth

32

are tuned to support dimensions of the cross sectional shape of the impeller

10

at a plurality of locations including its opposite ends so as to prevent the occurrence of distortion of the vanes

11

at the opposite axial ends of the impeller

10

.

Moreover, the outer periphery support sections

31

and the inner peripheral teeth

32

of each belt-like connecting portion

30

has a quardrilateral cross sectional shape which can be deformed in such a manner as indicated by broken lines in FIG.

22

.

Deforming the cross sectional shape of the outer periphery support sections

31

(and the inner peripheral teeth

32

) can be implemented by forming the outer peripheral teeth

42

of each large wheel

40

into slant embossed or padding shapes (i.e., trapezoidal cross sectional shapes) inclined with respect to the rotational direction B (see broken lines in FIG.

22

).

With the structures as shown in FIG.

21

and

FIG. 22

, the vanes

11

are fixedly secured to the outer periphery support sections

31

of each belt-like connecting portion

30

located on the opposed side of the inner peripheral teeth

32

in such a manner that they can always hold a constant vane angle θ irrespective of the load of the fluid.

Moreover, it goes without saying that the outer periphery support sections

31

of each belt-like connecting portion

30

have a degree of hardness capable of maintaining the constant vane angle θ even in the arc portion

10

b

in which each belt-like connecting portion

30

is curved.

Generally, the outer periphery support sections

31

are made of rubber materials similar to those used for the main belt body, but they may instead be made of resin materials, or metal pieces engagingly attached to the main belt body may be used for the same purpose.

In addition, though rubber materials are used for the main belt body, they may be combined with reinforcing materials such as cloths, fibers, metal wires or the like so as to further increase the strength thereof.

Furthermore, if the outer peripheral teeth

42

of the large wheel

40

are formed into the slant embossed or padding shapes, as shown by the broken lines in

FIG. 22

, the inner peripheral teeth

32

of each belt-like connecting portion

30

can follow the slant embossed or padding shapes so that they are inclined together with the outer periphery support sections

31

, thereby making it possible to deform the outer periphery support sections

31

in a manner as inclined toward the rotational direction B.

As a consequence, the vane angle θ in the straight portion

10

a

and the arc portion

10

b

is not fixed to a constant value, so it is possible to set the vane angle θ in the arc portion

10

b

engaging the outer peripheral teeth

42

of the large wheels

40

to be greater than that in the straight portion

10

a.

That is, when the inner peripheral teeth

32

of the belt-like connecting portions

30

is placed into engagement with the complementarily shaped grooves (trapezoidally toothed grooves) of the outer peripheral teeth

42

of the corresponding large wheels

40

, the inner peripheral teeth

32

and the outer periphery support sections

31

of the belt-like connecting portions

30

fall or incline forward in the rotational direction B along the trapezoidally toothed grooves of the large wheels

40

, thus resulting in an increase in the vane angle θ in the arc portion

10

b.

At this time, the inner peripheral teeth

32

of the belt-like connecting portions

30

can be shaped into the slant embossed or padding configurations so as to conform to the shape of the outer peripheral teeth

42

of the large wheels

40

, whereby the cross sectional shapes of the inner peripheral teeth

32

of the belt-like connecting portions

30

can be smoothly deformed while following the outer peripheral teeth

42

of the large wheels

40

.

In general, since it is preferable to set the vane angle θ in the arc portion

10

b

greater than that in the straight portion

10

a

, the vane angle θ in the arc portion

10

b

is set in advance to a smaller value matching the vane angle θ in the straight portion

10

a

, and by providing the above-mentioned deformation structure to the belt-like connecting portions

30

, the vane angle θ in the arc portion

10

b

at the locations of the large wheels

40

is then set greater than the initially set value.

Moreover, in cases where the belt-like connecting portions

30

are caused to deform by means of the corresponding large wheels

40

having the trapezoidally toothed grooves in this manner, it is preferred that the large wheels

40

be integrally coupled with the drive shaft

20

in alignment therewith so as to have a driving function as well. On the other hand, in this case, any of the small wheels

50

are not coupled with the drive shaft

20

and they are provided with no toothed groove but merely have the pulley function alone for a V belt.

Moreover, though the inner peripheral teeth

32

of the belt-like connecting portions

30

may have ordinary flat or square heads (crests), it is preferred that they be formed into slant embossed or padding shapes similar to those of the the outer peripheral teeth

42

of the large wheels

40

as referred to above, thus making it possible to further improve the deformation effect.

In addition, the toothed groove structure (parallel shape) of at least one of the inner peripheral teeth

32

of the belt-like connecting portions

30

and the outer peripheral teeth

42

of the large wheels

40

can be modified to change the vane angle θ in the centrifugal vane array, and hence to this end, only the inner peripheral teeth

32

of the belt-like connecting portions

30

may be formed into the slant embossed or padding shapes.

Further, although in the above-mentioned twelfth through fourteenth embodiments, the belt-like connecting portions

30

are provided on the opposite axial ends of the impeller

10

, as illustrated in

FIG. 18

, two or more belt-like connecting portions may be provided at a plurality of arbitrary locations as desired.

In this case, too, it is needless to say that the inner peripheral teeth

32

of the respective belt-like connecting portions

30

and the outer peripheral teeth

42

of the large wheels

40

are respectively tuned to support dimensions of the cross sectional shape of the impeller

10

so as to prevent the occurrence of distortion of the vanes

11

at the opposite axial ends of the impeller

10

.

Embodiment 15

Although in the above-mentioned twelfth embodiment, the cross sectional shape of the impeller

10

is formed into a generally D-shaped configuration, it may be of a substantially spindle-shaped configuration.

FIG.

23

and

FIG. 24

are cross sectional side views illustrating a once-through blower having an impeller

10

of a substantially spindle-shaped cross sectional configuration according to a fifteenth embodiment of the present invention illustrating a shape of the impeller

10

, in which the same or corresponding parts or elements as those in the aforementioned embodiments are identified by the same symbols while omitting a detailed description thereof.

In FIG.

23

and

FIG. 24

, a small wheel

50

D is integrally formed with the above-mentioned drive shaft

20

(see FIG.

16

), while omitting the drive shaft

20

.

The small wheel

50

D acts to pull a belt-like connecting portion

30

in opposition to a large wheel

40

so as to form a pair of straight portions

10

a

1

and

10

a

2

(linear vane arrays) with the small wheel

50

D located as the center.

FIG.

23

and

FIG. 24

illustrate an example including the single large wheel

40

and the single small wheel

50

D.

In this manner, the cross sectional shape of the impeller

10

comprising the belt-like connecting portion

30

is formed into a substantially spindle-shaped configuration including the arc portion

10

b

, which is formed by a part of the belt-like connecting portion

30

wrapped around the large wheel

40

, and the straight portions

10

a

1

and

10

a

2

, which are formed by the parts of the belt-like connecting portion

30

disposed between the large wheel

40

and the small wheel

50

D that is arranged in opposition to the large wheel

40

.

Here, the cross sectional shape of the impeller

10

is formed into the spindle-shaped configuration, but it may be of any other arbitrary configuration if those parts of the belt-like connecting portion

30

arranged in opposition to the arc portion

10

b

can perform linear motion.

Incidentally, the outer peripheral teeth (toothed grooves) for driving the belt-like connecting portion

30

may be provided on the small wheel

50

D which acts as a drive shaft, and hence, in this case, the small wheel

50

D may be coupled with the rotating shaft of a motor M (see

FIG. 18

) so as to act as a drive shaft for synchronized rotation, whereas the large wheel

40

may comprise a simple guide roller having no toothed groove.

However, in cases where the vane angle θ in the arc portion

10

b

is controlled to differ from the vane angle θ in the straight portions

10

a

1

and

10

a

2

as described before, the large wheel

40

functions as a drive shaft having toothed grooves.

In FIG.

23

and

FIG. 24

, the belt-like connecting portion

30

is pulled by the small wheel

50

D to form the straight portions

10

a

1

and

10

a

2

(linear vane arrays), and it is supported from its inside by the large wheel

10

to form the arc part

10

b

(centrifugal vane array).

In this manner, by pulling the belt-like connecting portion

30

by means of the single small wheel

50

D, it is possible to form the spindle-shaped configuration (including two straight vane arrays

10

a

1

,

10

a

2

), unlike the case in which the D-shaped configuration (including three linear vane arrays) is formed by the use of two small wheels (i.e., one drive shaft

20

and one small wheel

50

) as described before with reference to FIG.

17

.

Moreover, as shown in FIG.

23

and

FIG. 24

, the large wheel

40

is arranged such that it is placed in contact at its right side with the linear vane arrays

10

a

1

and

10

a

2

. As a result, slackening (or vibration) of the straight portions

10

a

1

and

10

a

2

can be suppressed by using parts of the large wheel

40

.

However, such a construction is not essential, and in cases where the above vibration might be caused, a damper guide may be provided for each of the straight portions

10

a

1

and

10

a

2

so as to suppress such vibration.

In this case, there are the following effects or merits as compared with the case in which the impeller

10

is formed into the D-shaped configuration as described with reference to FIG.

17

. That is, the occupation ratio of the straight portions

10

a

1

and

10

a

2

to the entire circumferential length of the impeller

10

increases, and the length of the arc portion

10

b

increases more than the length of a semicircle (π radian).

In this case, however, since incoming streams of the suction fluid Fa are forced to flow in such directions as to mutually impinge against one another at the location of the small wheel

50

D, it is necessary to avoid that the small wheel

50

D is arranged too far from the large wheel

40

or the outside diameter of the small wheel

50

D is reduced excessively, resulting in too small a vertical angle included by the straight portions

10

a

1

and

10

a

2

.

Moreover, in this case, the linear motion of the belt-like connecting portion

30

is distorted in the part of the small wheel

50

D, which can be regarded as a centrifugal blower that is locally performing a circular motion. Thus, it is desired to take an appropriate measure for preventing the action of reverse flow.

For instance, the outside diameter of the central shaft of the small wheel

50

D may be increased so as to block the inflow of fluid from the vicinity of the small wheel

50

D, or a barrier wall segment

15

(see

FIG. 23

) may be provided for preventing the fluid from flowing therein.

In addition, in order to further increase the sealing effect of a partition PA for separating a suction flow Fa and a discharge flow Fb from each other, an auxiliary partition segment

16

(see

FIG. 23

) for separation may be arranged inside the large wheel

40

which is disposed in confrontation with the partition PA.

In the above-mentioned twelfth through fifteenth embodiments, for a mechanism of the belt-like connecting portion

30

, there has been used at least one toothed belt, which is most simple in construction, reliable and stable in operation, but another suitable element such as a V belt, a flat belt, a chain or the like can be arbitrarily employed as long as the timings for driving or feeding the impeller at its opposite ends, which are arranged in the axial direction of the rotating shaft of the once-through blower, can be synchronized with each other.

Although the present invention has been shown and described herein while taking the once-through blower as a typical example, it goes without saying that the present invention is applicable to once-through pumps for driving other fluids, powders or the like.

While the invention has been described in terms of preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the appended claims.

Number	Date	Country	Kind
2001-001625	Jan 2001	JP
2001-192526	Jun 2001	JP

Once-through pump

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Term Extension

Abstract

Description

Claims

Priority Claims (2)

US Referenced Citations (1)