Information
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Patent Grant
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6758657
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Patent Number
6,758,657
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Date Filed
Thursday, June 20, 200222 years ago
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Date Issued
Tuesday, July 6, 200419 years ago
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Inventors
-
Original Assignees
-
Examiners
- Yu; Justine R.
- Gray; Michael K.
Agents
- Renner, Kenner, Greive, Bobak, Taylor & Weber
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CPC
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US Classifications
Field of Search
US
- 417 4131
- 417 4101
- 417 4237
- 417 42314
- 417 415
- 417 441
- 417 416
- 417 417
- 417 18
- 092 605
- 092 130 C
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International Classifications
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Abstract
A pump (10) has a housing which forms a pump chamber (17) having a wall (18). Inlet and outlet valve assemblies (19, 20) communicate with the chamber (17) and, respectively, allow fluid to be received in, and discharged from, the chamber (17). An armature (27) carries a plunger (28) and is reciprocatably moved by an electromagnetic coil assembly (25). A coil spring (44) biases the plunger (28) toward a stop surface (41) positioned adjacent to the plunger (28). Upon activation of the coil assembly (25), the plunger. (28) is moved against the force of the spring (44) such that a diaphragm (31) carried by the plunger (28) moves into the chamber (17) without engaging the wall (18) to discharge fluid through the outlet valve assembly (20). When the coil assembly (25) is deactivated, the spring (44) moves the plunger (28) toward the stop surface (41) without allowing it to engage the stop surface (41) to draw fluid in through the inlet valve assembly (19). In another embodiment, a second coil spring (45) is positioned so as to bias the plunger (28) away from the stop surface (41) to prevent the plunger (28) from engaging the stop surface (41) during priming of the pump (10).
Description
TECHNICAL FIELD
This invention relates to an electromagnetically driven diaphragm pump. More particularly, this invention relates to such a pump which provides a continuous low flow of fluid at a high pressure.
BACKGROUND ART
Oscillating pumps such as that shown in U.S. Pat. No. 5,915,930 are well known in the art, but they lack accuracy when a low flow rate is desired. Those pumps which can provide accuracy in low flow/high pressure applications are noisy because the pumping element moves from seat to seat, thereby generating noise at each end of the stroke. Moreover, these pumps require multiple seals to the atmosphere and cannot always be designed to be compact.
DISCLOSURE OF THE INVENTION
It is thus an object of the present invention to provide an electromagnetically driven diaphragm pump for continuous low flow, high pressure applications.
It is another object of the present invention to provide a pump, as above, which is quiet during operation.
It is a further object of the present invention to provide a pump, as above, in which the diaphragm seals the pump chamber.
It is an additional object of the present invention to provide a pump, as above, which is compact and economically manufactured.
These and other objects of the present invention, as well as the advantages thereof over existing prior art forms, which will become apparent from the description to follow, are accomplished by the improvements hereinafter described and claimed.
In general, a pump made in accordance with the present invention includes a housing having a pump chamber defined by at least one wall. An inlet area includes a valve which allows fluid to be received in the chamber, and an outlet area includes a valve which allows fluid to be discharged from the chamber. An armature carries a plunger, and a stop surface is positioned adjacent to one end of the plunger. Means are provided to bias the plunger toward the stop surface. A diaphragm which seals the chamber is carried by the other end of the plunger. An electromagnetic coil is provided which, when activated, moves the armature to overcome the force of the means to bias so that the diaphragm is moved into the chamber without engaging the wall of the chamber to discharge fluid through the outlet area. Upon deactivation of the coil, the means to bias moves the plunger toward the stop surface but the plunger does not engage the stop surface as fluid is drawn in through the inlet area and into the chamber.
A preferred exemplary pump incorporating the concepts of the present invention is shown by way of example in the accompanying drawings without attempting to show all the various forms and modifications in which the invention might be embodied, the invention being measured by the appended claims and not by the details of the specification.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is somewhat schematic cross section of a pump made in accordance with the present invention showing the stroking plunger in the neutral position.
FIG. 2
is a fragmentary view similar to
FIG. 1
but showing the plunger in the fully down position to draw fluid into the pump.
FIG. 3
is a fragmentary view similar to
FIGS. 1 and 2
but showing the plunger in the fully up position to discharge fluid from the pump.
FIG. 4
is a somewhat schematic cross section of a pump made in accordance with another embodiment of the present invention showing the stroking plunger in the neutral position.
FIG. 5
is a fragmentary view similar to
FIG. 4
but showing the fully down position to draw fluid into the pump.
FIG. 6
is a fragmentary view similar to
FIGS. 4 and 5
but showing the plunger in the fully up position to discharge fluid from the pump.
PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION
One embodiment of a pump made in accordance with the concepts of the present invention is shown in
FIGS. 1-3
and is indicated generally by the numeral
10
. Pump
10
includes a valve body
11
which at one end
12
forms the top of pump
10
and at the other stepped end
13
is connected by suitable fasteners (not shown) to one end of coil adapter
14
. An end cap
15
is connected to the other end of coil adapter
14
, as by fasteners
16
. Preferably, end cap
15
is toroidal in shape having a central opening. Together, valve body
11
, coil adapter
14
and end cap
15
form a pump housing.
The pump housing forms a pump chamber
17
defined on one end by an upper wall
18
formed in valve body
11
, wall
18
being opposed and generally parallel to top wall
12
. The sides of chamber
17
communicate with radially aligned fluid inlet and fluid outlet areas which respectively carry an inlet valve assembly, generally indicated by the numeral
19
, and an outlet valve assembly generally indicated by the numeral
20
. Valve assemblies
19
and
20
are essentially identical and are shown as including a conventional poppet valve
21
which is positionable on a valve seat
22
to close the valve assembly or positionable away from the valve seat
22
to allow fluid to pass through the valve assembly. Each valve assembly
19
,
20
also includes a connector
23
which is threaded into valve body
11
and is adapted to receive a hose or other conduit to provide fluid to inlet valve assembly
19
and take fluid away from outlet valve assembly
20
. An o-ring
24
may be provided between each valve seat
22
and each connector
23
.
Although the valve assemblies
19
and
20
are shown as including conventional poppet valves
21
, the exact type of valve employed is not critical to the present invention. In fact, most any type of alternative valves, such as, umbrella valves, duckbill valves, flapper valves, check valves, or the like could be utilized in the present invention. Moreover, although the inlet and outlet areas are shown as being in line and communicating with opposite sides of chamber
17
, such is not a requirement of the present invention. Rather, for example, the fluid flow could enter chamber
17
radially and leave axially through a valve assembly received in top wall
12
of valve body
11
, or vice-versa. Similarly, the fluid could both enter and exit chamber
17
through top wall
12
without departing from the concepts of the present invention.
A conventional toroidal-shaped electromagnetic coil assembly
25
is received within coil adapter
14
and is provided with electrical A.C. power via cord
26
. An armature
27
is positioned within coil assembly
25
, and, as is well known in the art, armature
27
reciprocates (upwardly and downwardly as oriented in the drawings) in response to the energization and de-energization of coil assembly
25
. While armature
27
can be confined within end cap
15
, when end cap
15
is provided with the central aperture previously described, when armature
27
reciprocates, a portion of it could extend out through the aperture in end cap
15
.
A plunger assembly, generally indicated by the numeral
28
, is carried by armature
27
. To that end, one end of plunger assembly
28
is formed with a threaded shaft
29
which is received by a collar
30
formed at the upper end of armature
27
. The fluid flow of pump
10
can be controlled by the extent to which shaft
29
is threaded into collar
30
.
The other end of plunger assembly
28
carries a diaphragm generally indicated by the numeral
31
. Diaphragm
31
can be a conventional elastomeric member having a central portion
32
which is received in chamber
17
. Central portion
32
can include a lip
33
which engages a flange
34
formed near the end of the head
35
of the plunger assembly
28
such that plunger assembly
28
engages diaphragm
31
. Diaphragm
31
then extends along the sides of the head
35
of plunger assembly
28
, and it folds back on itself to form a convolution, as at
36
, all around head
35
of plunger assembly
28
. The ends
37
of diaphragm
31
are captured between a step of stepped surface
13
of valve body
11
and a corresponding step of a stepped surface
38
formed at the top of coil adapter
14
. It should be noted that diaphragm
31
thus seals chamber
17
. That is, no seals are necessary between valve body
11
and coil adapter
14
, nor are any seals required between coil adapter
14
and end cap
15
. Although when using poppet valves
21
, -rings
24
are desirable, for certain other types of valves contemplated by the present invention, such as umbrella/duckbill valves, no
0
-rings are necessary and diaphragm
31
thus provides the only seal in the entire pump
10
.
A spring retainer
39
is received on the inside of coil assembly
25
above armature
27
and is maintained in position by virtue of its circumferential lip
40
being retained between a step of stepped surfaces
13
of valve body
11
and a mating step of stepped surfaces
38
of coil adapter
14
. A torus-shaped stop surface
41
is formed at the other end of retainer
39
and, as shown in
FIG. 3
, dependent on the length of the stroke of armature
27
, its collar
30
may extend up through stop surfaces
41
.
A circular plate
42
having a circumferential tab
43
is formed on plunger assembly
28
, plate
42
being positioned on shaft
29
above the threaded end thereof and below plunger head
35
. Plunger assembly
28
also includes a coil spring
44
which extends between a step of stepped surface
38
of adapter
14
and tab
43
of plunger assembly
28
to bias plunger assembly
28
away from wall
18
of chamber
17
and toward stop surface
41
of retainer
39
.
In operation of pump
10
, at the point of starting, plunger assembly
28
can be in its neutral position, as shown in FIG.
1
. Upon activation of coil assembly
25
, armature
27
and plunger assembly
28
move upwardly to the
FIG. 3
position, overcoming the bias of spring
44
to force fluid in chamber
17
out of valve assembly
20
. It should be noted, however, that as shown in
FIG. 3
, plunger
28
, and in particular diaphragm portion
32
, do not touch or otherwise contact wall
18
of chamber
17
. As would be evident to one of ordinary skill in the art, the range of travel of armature
27
, and thus plunger assembly
28
, is a function of the power level on the coil assembly
25
, the mass of the armature
27
and plunger
28
, and the power of spring
44
. A balance of these factors prohibits the plunger
28
and diaphragm portion
32
from contacting wall
18
and creating an undesirable noise. In actuality, since half wave rectified voltage is preferably being applied to coil assembly
25
, this noise, or chattering, would be repeated sixty times per second were plunger assembly
28
allowed to contact wall
18
.
During the other half cycle, power to coil assembly
25
is off. At this time, under the influence of spring
44
, plunger assembly
28
is moved to the extreme down position shown in FIG.
2
. As a result, a partial vacuum is created in chamber
17
causing valve assembly
19
to open, thereby drawing fluid into chamber
17
. As should be evident to one skilled in the art, by balancing the force of the spring, as discussed above, the movement of plunger assembly
28
can be controlled so that stop surface
41
is not contacted by plate
42
upon the intake stroke.
Pump
10
shown in
FIGS. 1-3
will thus run silently during normal operating conditions. However, it is possible that during initial priming of the pump, or in other start-up situations where the fluid in chamber
17
may be a gas (air), the balance created in the pump of
FIGS. 1-3
may not be able to prevent operating noise during priming. That is, in this situation, it is possible that plunger assembly
28
could engage stop surface
41
on the downstroke.
Such a possibility may be prevented by the embodiment of the pump
10
shown in
FIGS. 4-6
. This embodiment is essentially identical to that shown in
FIGS. 1-3
, and therefore, the same reference numerals have been applied to the same elements, and the description thereof relative to
FIGS. 1-3
is equally applicable to the embodiment of
FIGS. 4-6
. However, in the
FIGS. 4-6
embodiment, plate
42
of plunger assembly
28
is positioned on shaft
29
further from the threaded end thereof, and a second coil spring
45
is positioned between tab
43
and stop surface
41
. Spring
45
thus biases plunger assembly
28
toward wall
18
of chamber
17
and will prevent plate
42
from contacting stop surface
41
in those versions of pump
10
whereby the armature
27
may be allowed to pass through end cap
15
. If the end cap
15
is closed, spring
45
will prevent armature
27
from engaging it.
Thus, the addition of spring
45
can be offered if the user is concerned about silent running during priming. However, its presence should also be taken into consideration during the normal pumping operation. That is, during the discharge stroke when pump
10
is moving to the
FIG. 6
position, spring
45
is acting in concert with coil assembly
25
against spring
44
, and during the intake stroke when pump
10
is moving to the
FIG. 5
position, the fact that spring
44
must overcome the force of spring
45
must be considered when balancing the system, as would be well known to one of ordinary skill in the art.
Thus, with or without spring
45
, during normal pumping conditions, pump
10
is running silent to continuously pump fluid from the inlet valve area, through chamber
17
, and through the outlet valve area. As a result, a pump
10
constructed as described herein substantially improves the art and otherwise accomplishes the objects of the present invention.
Claims
- 1. A pump comprising a housing, a pump chamber in said housing defined by at least one wall, an inlet area having a valve allowing fluid to be received in said chamber, an outlet area having a valve allowing fluid to be discharged from said chamber, an armature, a plunger carried by said armature, a stop surface adjacent to one end of said plunger, means to bias said plunger toward said stop surface, a diaphragm carried by the other end of said plunger and sealing said chamber, and an electromagnetic coil which when activated moves said armature to overcome the force of said means to bias so that said diaphragm is moved into said chamber without engaging said wall to discharge fluid through said outlet area, and upon deactivation of said coil, said means to bias moves said plunger toward said stop surface without engaging said stop surface to draw fluid through said inlet area and into said chamber.
- 2. The pump of claim 1 further comprising means to bias said plunger away from said stop surface.
- 3. The pump of claim 1 wherein said plunger includes a threaded shaft and said armature includes a collar to receive said shaft, the extent of threading of said shaft into said collar controlling the amount of fluid flow.
- 4. The pump of claim 1 further comprising a retainer member carried by said housing, said stop surface being a portion of said retainer member.
- 5. The pump of claim 4 wherein said plunger includes a plate and further comprising a spring positioned between said plate and said stop surface.
- 6. The pump of claim 5 wherein said plate includes a circumferential tab, said spring being positioned between said tab and said stop surface.
- 7. The pump of claim 1, said plunger having a head including a flange, said diaphragm being positioned on said head and having a lip received in said flange.
- 8. The pump of claim 7, said diaphragm having ends engaged by said housing to seal said chamber.
- 9. The pump of claim 1 wherein said housing includes a valve body carrying said valves and having said chamber, a coil adapter carrying said coil and attached to said body, and an end cap attached to said coil adapter.
- 10. The pump of claim 9 wherein said diaphragm has ends carried between said valve body and said coil adapter.
- 11. The pump of claim 9 wherein said plunger includes a plate, and said means to bias includes a spring extending between said plate and said coil adapter.
- 12. The pump of claim 11 wherein said plate includes a circumferential tab, said spring being positioned between said tab and said stop surface.
- 13. The pump of claim 11 further comprising a second spring extending between said plate and said stop surface.
- 14. The pump of claim 12 further comprising a second spring extending between said tab and said stop surfaces.
- 15. The pump of claim 9 further comprising a retainer having a portion positioned between said valve body and said coil adapter, said retainer including said stop surface.
US Referenced Citations (6)