Information
-
Patent Grant
-
6435844
-
Patent Number
6,435,844
-
Date Filed
Monday, September 25, 200024 years ago
-
Date Issued
Tuesday, August 20, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Freay; Charles G.
- Rodriguez; William
Agents
-
CPC
-
US Classifications
Field of Search
US
- 417 395
- 417 412
- 417 4131
- 417 383
- 417 384
- 417 540
- 417 543
-
International Classifications
-
Abstract
A diaphragm pump comprising a first diaphragm operated with a driving mechanism such as a crank mechanism, a second diaphragm disposed so as to form an air chamber between the first diaphragm and the second diaphragm, and a pump chamber formed by the second diaphragm and a casing or the like, wherein the a pressure in the air chamber is changed by operating the first diaphragm with the driving mechanism and the second diaphragm is deformed by a change of the pressure in the air chamber to perform a pump function.
Description
BACKGROUND OF THE INVENTION
a) Field of the Invention:
The present invention relates to a pump which is used in a hot water supply apparatus or the like for feeding hot water.
b) Description of the Prior Art
An impeller pump is conventionally used as a pump in a hot water supply apparatus such as a jar, a pot or the like for feeding a liquid at a relatively high temperature.
This impeller pump has such a configuration as that shown in
FIG. 1
, and when the pump is to be used for feeding hot water, a hole
30
a
is formed in a bottom of a vessel
30
of a hot water supply apparatus to be filled with hot water and a suction port of the pump is connected to the hole. In
FIG. 1
which illustrates the configuration of the impeller pump, a reference numeral
31
represents a casing of the pump, a reference numeral
32
designates a partition panel which airtightly partitions a pump chamber
33
from a driving section
34
, a reference numeral
35
denotes a shaft which is supported by a supporting member
36
, a reference numeral
37
represents a holding member for holding an impeller and a magnet which are disposed rotatably around the shaft
35
, a reference numeral
38
designates an impeller which rotates together with the holding member
37
, and a reference numeral
39
denotes a follower magnet which rotates together with the holding member
37
: all of these members being disposed in the pump chamber
33
. In the driving section
34
partitioned with the partition panel
32
, a driving magnet
40
which is rotated with a motor
41
is disposed so as to oppose to the follower magnet
39
with the partition panel
32
interposed.
This impeller motor rotates the driving magnet
40
by driving the motor
41
and rotates a follower magnet
39
which is magnetically coupled with the driving magnet
40
by rotating the driving magnet
40
. When the follower magnet
39
is rotated, the impeller
38
is rotated to perform a pump function.
By the pump function of the impeller
38
, hot water is sucked out of the vessel
30
, sucked through a suction port
42
of the impeller pump and discharged from a discharge port
43
.
Furthermore, a diaphragm pump is known as a pump which supplies a liquid or the like.
The diaphragm pump has a configuration shown in
FIG. 2
, wherein a reference numeral
50
represents a motor, a reference numeral
51
designates a crank body which is fixed to an output shaft
50
a
of the motor
50
, a reference numeral
52
designates a driving shaft which is pressed and fixed into the crank body
51
at a location eccentric from the output shaft
50
a
, a reference numeral
53
denotes a connecting rod which is rotatably coupled with the driving shaft
52
and a reference numeral
54
represents a diaphragm made of a synthetic rubber or the like which is fixed to a tip of the connecting rod. Formed as an outer circumferential portion of the diaphragm
54
is a sealing portion which is sandwiched between a clamp plate
55
and a casing
66
to seal a pump chamber from external air. Furthermore, a reference numeral
61
represents a suction port, a reference numeral
62
designates a discharge port, and check valves
58
and
59
such as leaf valves are disposed in the suction port
61
and the discharge port
62
respectively.
When the motor
50
is driven and its output shaft
50
a
is rotated, the diaphragm pump which has the configuration described above rotates the crank body
51
, the driving shaft
52
moves the diaphragm
54
upward and downward by way of the connection rod
53
and, upward and downward movements of the diaphragm
54
increase and decrease a volume of the pump chamber
60
. When the volume of the pump chamber
60
is increased, the leaf valve
58
opens and a fluid is sucked through the suction port
61
and when the volume of the pump chamber
50
is decreased, the leaf valve
59
opens and the fluid is discharged from the discharge port
62
, thereby performing a pump function.
When hot water is sucked from a vessel and supplied using an impeller pump such as that shown in
FIG. 1
, air bubbles are produced in the pump. Since a vapor pressure is lower in the vicinity of a rotating center of the impeller
38
, that is, in the vicinity of the shaft
35
in particular than those in other locations in the pump chamber
33
, the produced air bubbles are collected in the vicinity of the shaft
35
, close the suction port
42
and make the hot water hardly flow, thereby remarkably lowering a hot water supply capability of the pump or disabling the pump from supplying the hot water in a worse case.
Furthermore, the impeller pump which is used for supplying hot water has a defect that the pump requires a high cost since it uses a large number of expensive parts such as two magnets of the driving magnet
40
and the follower magnet
39
as shown in
FIG. 1
to maintain sufficient airtightness.
Furthermore, a diaphragm pump such as that shown in
FIG. 2
is not disabled from supplying hot water since the pump is capable of exhausting bubbles at a certain degree even when bubbles are produced. However, the diaphragm pump has a defect that it cannot assure a sufficient reliability from a viewpoint of a service life of the diaphragm which is made of the synthetic rubber since a certain kind of synthetic rubber adds an abnormal taste or an abnormal odor to hot water and is hardened dependently on a vapor temperature or the like.
Furthermore, some of diaphragm pumps use metal diaphragms.
FIG. 3
shows an example of diaphragm pump using a metal diaphragm
70
as a diaphragm and has a configuration substantially the same as that of the diaphragm pump using the diaphragm made of the synthetic rubber shown in
FIG. 2
, except for the metal diaphragm
70
which is sandwiched and fixed between a connecting rod
53
and a retainer
71
. Accordingly, a pump function of the diaphragm pump shown in
FIG. 3
which is similar to that of the diaphragm pump shown in FIG.
2
and is performed by deforming the metal diaphragm so as to change a volume of a pump chamber.
The diaphragm pump which uses the metal diaphragm has a defect that stresses are concentrated on a middle portion of the metal diaphragm (an outer circumference of the connecting rod
53
) when the metal diaphragm is displaced largely, whereby this portion is liable to be broken and the diaphragm has an extremely short service life. In order to correct this defect, the diaphragm pump is configured large or when the pump is configured to cause a relatively short displacement of the metal diaphragm, the diaphragm pump has another defect that it cannot exhaust air bubbles sufficiently and lowers a flow rate.
Furthermore, a diaphragm pump disclosed by Japanese Patent Kokai Application No Hei 10-281070 is known as another conventional diaphragm pump.
This pump has a configuration shown in
FIG. 4
, wherein the pump comprises a pump chamber
74
formed by an upper half
71
of a pump body
70
and a diaphragm
73
, a piston
75
attached to a lower half
72
of the pump body
70
, and an operating fluid
76
sealed between the piston
75
and the diaphragm
73
.
The conventional pump shown in
FIG. 4
performs a pumping action by producing a pressure of the operating fluid with an action of the piston
75
, deforming the diaphragm
73
with the pressure, and increasing and decreasing a volume of the pump chamber.
Judging from embodiments, this diaphragm pump basically uses a liquid as the operating fluid though description is made that air (a gas) can be used as the operating fluid and the diaphragm pump basically uses a sheet of expansible and contractible synthetic resin such as teflon or synthetic rubber as the diaphragm
73
though description is made that a thin metal plate is used as the diaphragm
73
.
When a piston is used for deforming the diaphragm
73
as in this conventional example, it is important to prevent a fluid from leaking and when a liquid is used as an operating fluid in particular, prevention of liquid leakage constitutes an important theme. Accordingly, sealing of a piston section poses a difficult problem and a diaphragm pump has a defect that it is made expensive for complete sealing.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a diaphragm pump which comprises a first diaphragm which is operated with a driving mechanism such as a crank mechanism, a second diaphragm disposed so as to form an air chamber between the first diaphragm and the second diaphragm, a pump chamber formed on a side opposite to the air chamber, an inflow port connected to the pump chamber by way of a check valve and an outflow port connected to the same pump chamber by way of a check valve, and is configured to perform a pump function by changing a pressure in the air chamber between the first diaphragm and the second diaphragm with a function of the crank mechanism, deforming the second diaphragm by the change of the pressure and changing a volume of the pump chamber by the deformation of the second diaphragm.
The diaphragm pump according to the present invention distributes stresses uniformly and is not problematic in its durability since the second diaphragm is deformed not directly by the driving mechanism such as the crank mechanism but by utilizing the pressure change in the air chamber even when a metal diaphragm which is resistant to high temperature hot water is used in the pump chamber, that is, even when metal diaphragm is used as the second diaphragm.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a diagram showing a configuration of a conventional impeller pump;
FIG. 2
is a diagram showing a configuration of a conventional diaphragm pump;
FIG. 3
is a diagram showing a configuration of another conventional diaphragm pump;
FIG. 4
is a diagram showing a configuration of still another conventional diaphragm pump;
FIG. 5
is a diagram showing a configuration of a first embodiment of the diaphragm pump according to the present invention;
FIG. 6
is a diagram showing another condition of the pump shown in
FIG. 5
;
FIG. 7
is a diagram showing a configuration of a second embodiment of the diaphragm pump according to the present invention; and
FIG. 8
is a diagram showing a configuration of a third embodiment of the diaphragm pump according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now, description will be made of the preferred embodiments of the present invention.
FIGS. 5 and 6
are diagrams showing a configuration of a diaphragm pump preferred as a first embodiment of the present invention, wherein a reference numeral
1
represents a motor, a reference numeral
2
designates a crank body which is fixed to an output shaft la of the motor
1
, a reference numeral
3
denotes a driving shaft which is fixed to the crank body
2
eccentrically from a rotating axis (the output shaft la) of the crank body, a reference numeral
4
represents a connecting rod attached to the driving shaft
3
, a reference numeral
5
designates a first diaphragm made of synthetic rubber or another material to which is a tip of the connecting rod
4
is attached, and reference numerals
6
and
7
denote a clamp plate and a spacer respectively which sandwich a sealing member
5
a
disposed on a circumference of the first diaphragm
5
. A reference numeral
9
represents a second diaphragm which is manufactured by drawing a metal plate such as a thin stainless steel plate into a corrugated form and sandwiched between the spacer
7
and a casing
10
. An air chamber
8
is formed between the first and second diaphragms
5
and
9
, and a pump chamber
12
is formed between the second diaphragm
9
and the casing
10
. Furthermore, reference numerals
13
and
14
designate check valves (leaf valves), a reference numeral
15
denotes an inflow port, a reference numeral
16
represents an outflow port, a reference numeral
17
represents an outflow hole
17
and a reference numeral
18
designates a cover. Furthermore, reference numerals
19
,
20
and the like designate O rings.
When the output shaft l
a
is rotated by driving the motor
1
in the diaphragm pump preferred as the first embodiment shown in
FIGS. 5 and 6
in a condition shown in
FIG. 5
, the driving shaft
3
which is fixed to the crank body
2
is also rotated and pushes up the connecting rod
4
.
FIG. 6
shows a condition where the driving shaft la makes half a rotation.
When the connecting rod
4
is pushed up by the rotation of the driving shaft
1
a
as in the condition shown in
FIG. 6
, the first diaphragm
5
is pushed up, thereby reducing a volume of the sealed air chamber
8
and enhancing a pressure in the air chamber
8
. The enhancement of the pressure in the air chamber
8
swells the second diaphragm
9
upward, thereby reducing a volume of the pump chamber
12
. The reduction of the volume of the pump chamber
12
causes a fluid in the pump chamber to open the leaf valve
13
from the outflow hole
17
and is discharged from the outflow port
16
.
When the output shaft
1
a
of the motor
1
is further rotated and the driving shaft
3
is rotated by way of the crank body
2
until it is set again in the condition shown in
FIG. 5
, the first diaphragm
5
is lowered, the pressure is lowered in the air chamber
8
, the second diaphragm
9
is lowered and the volume of the pump chamber
12
is enlarged, whereby the fluid opens the leaf valve
13
from the inflow port
15
and enters the pump chamber
12
.
A pump function is performed by repeating operations described above.
In the pump preferred as the first embodiment of the present invention, the first diaphragm
5
is made of synthetic rubber, synthetic resin or the like and is deformable. Therefore, deformation of the first diaphragm
5
functions to prevent the motor which drives this diaphragm from being locked even when a flow path is intercepted due to a trouble or an accident and hot water does not flow in the discharge port of the pump or a hot water supply flow path beyond the discharge port. Accordingly, the motor is free from a fear that the motor is overheated in a locked condition.
The diaphragm pump preferred as the first embodiment of the present invention rarely allows the metal diaphragm to be broken and has a long service life since the second diaphragm
9
which performs the pump function is deformed upward and downward without unreasonableness due to pressure changes in the air chamber. Since bubbles produced in the pump chamber
12
are pushed out together with the liquid, the diaphragm pump preferred as the first embodiment is not disabled from flowing out the liquid though the liquid is flowed out in an amount reduced by a volume of the bubbles.
A second embodiment of the present invention has a configuration shown in
FIG. 7
, and is characterized in that a plate like member
21
which partitions into two an air chamber
8
between a first diaphragm
5
and a second diaphragm
9
is disposed in place of the spacer
7
in the pump shown in
FIGS. 5 and 6
, that an orifice
22
is formed in the plate like member
21
and that the orifice
22
composes breakage detecting means. The second embodiment is substantially the same as the first embodiment, except for the plate like member which has the orifice
22
.
When the first diaphragm
5
is moved upward and downward due to a movement of the driving mechanism, air flows from the air chamber through the orifice
22
and changes a pressure in the air chamber
8
, and the second diaphragm
9
moves like that in the pump preferred as the first embodiment, whereby the second embodiment performs a pump function.
The pump preferred as the first embodiment detects an abnormal condition only after the first diaphragm made of synthetic rubber or the like is broken since the pump continues the pump function by continuously moving the first diaphragm
5
upward and downward even when the second diaphragm
12
is broken and a fluid such as hot water leaks and enters the air chamber.
In contrast, the pump preferred as the second embodiment in which the air chamber is partitioned by the plate like member
21
serving also as a spacer and air flows through the orifice
22
to change the pressure is capable of detecting an abnormal condition before the first diaphragm is broken since the hot water flows through the orifice in a small amount per unit time due to viscosity of a liquid and a normal pump function is not performed even when the second diaphragm
9
is broken and hot water flows into the air chamber.
Accordingly, the second embodiment does not continue an operation without detecting the abnormal condition when the second diaphragm is broken and prevents water leakage from being caused by breakage of the first diaphragm.
Even when the second diaphragm is broken and the fluid (hot water) flows into the air chamber in the second embodiment, the first diaphragm
5
which is made of the synthetic rubber or synthetic resin is deformed (expanded) and the motor
1
which drives the first diaphragm
5
is not set in a locked condition.
In a case where a piston is used in place of the first diaphragm
5
as in the conventional example shown in
FIG. 4
, in contrast, the fluid enters on a piston side of the plate like member
21
when the second diaphragm is broken and the fluid flows into the air chamber, thereby the piston cannot move and the motor which drives the piston is set in a locked condition. As a result, the breakage of the second diaphragm constitutes a highly hazardous condition where the motor or the like is overheated and emits smoke.
FIG. 8
is a diagram showing a third embodiment of the diaphragm pump according to the present invention.
A pump preferred as the third embodiment is characterized in that an accumulator
24
which is made of silicone rubber or the like is added to the cover
18
and substantially the same as the pump preferred as the first embodiment or the second embodiment except for the accumulator.
The pump preferred as the first or the second embodiment discharges a liquid each time the motor
1
makes half a rotation and discharges the liquid as a pulsating flow. That is, a liquid flow oscillates. Accordingly, the pump causes a liquid splashing phenomenon beyond the outflow port, for example, from an outflow port of a pot or the like.
In the third embodiment described above, the accumulator
24
which is made of silicone rubber or the like is attached to the cover
18
and connected to a flow path or the like communicated with the outflow port so that an amount of a discharged fluid is made nearly constant by increasing and decreasing a volume of air in the accumulator
24
even when a liquid which opens the leaf valve from the pump chamber and flows through the outflow port pulsates. Speaking concretely, the third embodiment is capable of reducing a pulsating flow by automatically reducing the volume of the air in the accumulator when the discharged fluid has a high pressure and enlarging the volume when the discharged fluid has a low pressure. Accordingly, a portion of the fluid flows into the accumulator and compresses air in the accumulator when a pressure is enhanced in the air chamber by a function of the first diaphragm
5
, the second diaphragm is deformed by the enhancement of the pressure, a volume of the pump chamber is reduced by deformation of the second diaphragm and the fluid is discharged from the pump chamber toward an outflow side, accordingly, a portion of the fluid to be discharged is accumulated in the accumulator. Successively, the first diaphragm functions to lower the pressure in the air chamber, the second diaphragm functions to enlarge the volume of the pump chamber and enlargement of the volume of the pump chamber causes the fluid to flow into the pump chamber from the inflow port. Simultaneously, an air pressure in the accumulator
24
causes the liquid accumulated in the accumulator
24
to be flowed toward the outflow port.
Accordingly, the pump preferred as the third embodiment flows the fluid from the inflow port into the pump chamber like the pump preferred as the first or second embodiment, thereby flowing the fluid in a constant amount toward the outflow side even while the fluid does not flow from the pump chamber to the outflow port.
Though the leaf vales
13
and
14
are used as check valves in the pumps preferred as the first, second and third embodiments shown in
FIGS. 5 through 8
, these valves may not be leaf valves so far as the valves serve as check valves.
Unlike the pump preferred as the first or second embodiment which produces the pulsating flow by alternately producing a condition where the fluid is flowed toward the outflow side by the pump function and another condition where the fluid is not flowed, the pump preferred as the third embodiment reduces a pulsating flow by always flowing the fluid at a certain degree even while the pump function is not performed.
As understood from the foregoing description, the third embodiment reduces the pulsating flow and allows the fluid to be always flowed out without completely stopping supplying the fluid while the pump is operating to supply the fluid.
Accordingly, hot water is not splashed by a pulsating flow from a hot water supply port when the pump preferred as the third embodiment is used as a pump for supplying hot water from a pot or the like.
The accumulator used in the third embodiment is not limited to a member of silicone rubber or the like having a form such as that shown in FIG.
7
and may be made of another material which cannot be deformed and have a form different from that shown in FIG.
7
. When the pump preferred as the third embodiment is used as liquid supply means of a hot water supply apparatus, for example, the accumulator may have an extremely small volume and may be a space (chamber) which is formed in the cover
18
, for example, and connected to a flow path communicated with the outflow port.
In any case, the accumulator disposed in the third embodiment may have an form and be made of any material or disposed at any location so far as the accumulator has a space of an adequate size and is located higher than a flow path to which the accumulator is connected to that a fluid can easily move from the accumulator into the flow path.
The present invention makes it possible to obtain a pump which is not disabled from flowing out a liquid due to bubbles and has high durability of a diaphragm which is not broken by hot water at a high temperature.
Claims
- 1. A diaphragm pump comprising: a first diaphragm which is operated with a driving mechanism driven by a motor; a second diaphragm which is disposed so as to form an air chamber between said first diaphragm and said second diaphragm; a pump chamber which is formed on a side opposite to the air chamber of said second diaphragm; an inflow port and an outflow port which are connected to said pump chamber respectively; and check valves which are disposed between said pump chamber and said inflow port, and between said pump chamber and said outflow port respectively, wherein said first diaphragm is deformed by operating said driving mechanism by driving said motor, the second diaphragm is deformed by increase and decrease of a pressure in the air chamber which is caused by deformation of said first diaphragm, and a volume of the pump chamber is changed by deformation of said second diaphragm, thereby flowing a fluid from the inflow port into the pump chamber and flowing the fluid from the pump chamber into the outflow port to perform a pump function.
- 2. The diaphragm pump according to claim 1, wherein a plate like member is disposed so as to partition said air chamber into two, an orifice is formed in said plate like member, and a volume of a section of said air chamber which is formed between said first diaphragm and said plate like member is increased and decreased by deforming said first diaphragm, thereby deforming said second diaphragm by way of said orifice to perform the pump function.
- 3. The diaphragm pump according to claim 1 or 2, wherein an accumulator is disposed in a flow path connected to said outflow port.
- 4. The diaphragm pump according to claim 1 or 2, wherein said second diaphragm is composed of a deformable thin metal plate.
- 5. The diaphragm pump according to claim 1 or 2, wherein said second diaphragm is composed of a corrugated thin metal plate.
- 6. The diaphragm pump according to claim 4, wherein an accumulator is disposed in a flow path connected to said outflow port.
- 7. The diaphragm pump according to claim 5, wherein an accumulator is disposed in a flow path connected to said outflow port.
Priority Claims (1)
Number |
Date |
Country |
Kind |
11-269869 |
Sep 1999 |
JP |
|
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4737083 |
Meyer |
Apr 1988 |
A |
6071090 |
Miki et al. |
Jun 2000 |
A |
Foreign Referenced Citations (1)
Number |
Date |
Country |
10281070 |
Oct 1998 |
JP |