JP2002221160A - Pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a failure of a pump device caused by the action of a excessive working fluid pressure to a driving chamber of the pump device. SOLUTION: Diaphragms 21 and 22 are movably mounted in a pump body 11, the driving chambers 25 and 26 for feeding and draining a working fluid are formed on one-side parts of the diaphragms 21 and 22, and pump chambers 27 and 28 for feeding and delivering a transferred fluid are formed on the other sides of the diaphragms 21 and 22. The volume of each the pump chambers 27 and 28 is varied by controlling the feeding and draining of the working fluid to/from the driving chambers 25 and 26 from a selector valve 33. A valve mechanism 51 for releasing the pressure of the driving chambers 25 and 26 to a low pressure side at the working limit positions of the diaphragms 21 and 22 without passing the selector valve 33 is installed. A slot 52 is formed in the center rod 24 of the valve mechanism 51, and through holes 53 and 54 on the driving chamber side and a through hole 55 on the low pressure side are bored in the pump body 11. The through hole 53 or 54 on the driving chamber side are allowed to communicate with the through hole 55 on the low pressure side through a groove 52 of the center rod 24 positioned at the movement limit position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a pump device having a diaphragm.

[0002]

2. Description of the Related Art As shown in FIG. 2, a double diaphragm pump includes a pump 1 movably provided in a pump body 1.
A pair of diaphragms 2 are connected by a center rod 3 slidably fitted to the pump body 1, and a drive chamber 4 for supplying and discharging a working fluid is provided on one side of each diaphragm 2. On the other side, pump chambers 5 for receiving and transferring the fluid to be transferred are provided.

[0003] The right and left driving chambers 4 are controlled by a switching valve 6.
By alternately controlling the supply and discharge of the working fluid to the left and right diaphragms 2
Is reciprocated to alternately expand and reduce the volume of the left and right pump chambers 5, and alternately sucks the fluid to be transferred from the suction port 7 into the left and right pump chambers 5 via the suction-side check valve 8. The fluid to be transferred, which is alternately discharged from the chamber 5 through the discharge-side check valve 9, is sent out from the discharge port 10.

[0004]

The working fluid is supplied to the switching valve 6.
Are alternately supplied to the left and right driving chambers 4 by switching operation, but are supplied to only one driving chamber 4 as shown in FIG. 3 due to a failure or malfunction of the switching valve 6 or the like. In this case, an excessive working fluid pressure acts on the drive chamber 4, causing an excessive expansion of the diaphragm 2 and an excessive load on the pump components at the interference portion a, which causes a reduction in the life of the components and a cause of breakage. Becomes

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to prevent a failure of a pump device due to an excessive working fluid pressure acting on a drive chamber of the pump device.

[0006]

According to a first aspect of the present invention, there is provided a pump body, a diaphragm movably provided in the pump body, and a working fluid provided and discharged on one side of the diaphragm. A drive chamber, a pump chamber provided on the other side of the diaphragm, through which the fluid to be transferred is taken in and out, a switching valve for changing the volume of the pump chamber by controlling the supply and discharge of the working fluid to and from the drive chamber, A pump device having a valve mechanism for releasing the pressure of the driving chamber to the low pressure side without passing through the switching valve.When the diaphragm operates to the operation limit position, the switching valve controls the supply and discharge of the working fluid to the driving chamber. Another valve mechanism acts to release the pressure in the drive chamber to the low pressure side, thereby preventing a failure of the pump device due to an excessive working fluid pressure acting on the drive chamber.

According to a second aspect of the present invention, in the pump device according to the first aspect, the pair of diaphragms are connected by a center rod slidably fitted to the pump body, and the valve mechanism comprises a center rod. , And a drive chamber side through hole and a low pressure side through hole which are formed in the pump body and are mutually communicated by a center rod groove at a movement limit position. However, it is simply configured by the groove of the center rod and the through hole of the pump body.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.

A plurality of pump body members 12, 13, 14, 15, 16 constituting the pump body 11 are fixed by bolts 17. Center pump body member 12 and left and right pump body members 1
A pair of diaphragms 21 and 22, that is, a peripheral edge of the diaphragm is sandwiched between the diaphragms 3 and 14, respectively.

The center portions of these diaphragms 21 and 22 are connected to both left and right ends of a center rod 24 slidably fitted in a rod fitting hole 23 of the center pump body member 12. It is linked in the left and right direction.

On one side of these left and right diaphragms 21 and 22, that is, on the side of the center pump body member 12, there are left and right drive chambers to which a working fluid having a pressure such as compressed air or pressurized liquid is supplied and discharged.
Left and right pump chambers 27 and 28 are provided on the other side of the left and right diaphragms 21 and 22, that is, on the left and right pump body members 13 and 14 side. ing.

The left and right drive chambers 25, 26 have working fluid holes 31,
An external switching valve 33 is connected and connected through 32. The switching valve 33 incorporates a movable valve element such as a spool that is switched by a solenoid or a pilot pressure (not shown). The switching operation of the movable valve element causes a pipe from a working fluid pressure source such as a compressor or a pump to pass through the pipe 34. By controlling the supply and discharge of the supplied working fluid to the left and right drive chambers 25 and 26, the volume of the pump chambers 27 and 28 is changed via the diaphragms 21 and 22.

The left and right pump body members 13 and 14 are provided with suction-side valve seats 35 and 36 and check valves 37 and 38 at the lower part, and discharge-side valve seats 39 and 40 and check valve 41 at the upper part. , 42 are provided, and on the suction side valve seats 35, 36, the lower pump body member 15 is provided.
A suction port 44 is communicated through a suction hole 43 formed in the pump body, and a discharge port 46 is communicated with the discharge side valve seats 39 and 40 through a discharge hole 45 formed in the upper pump body member 16. ing.

A valve mechanism 51 which allows the pressure in the drive chambers 25 and 26 to escape to the low pressure side without passing through the switching valve 33 at the operation limit positions of the diaphragms 21 and 22 is provided at the center pump body member 12 and the center rod 24.
Is provided.

The valve mechanism 51 includes a groove 52 provided on the peripheral surface at the center of the center rod 24 and a pump body member at the center.
A simple configuration is provided by a plurality of through holes 53, 54, and 55 that are formed in the rod 12 and communicate with a plurality of axial positions of the rod fitting hole 23.

The drive chamber side through-holes 53 and 54 provided symmetrically on the left and right portions of the pump body member 12 communicate with the left and right drive chambers 25 and 26, respectively. One of them is communicated with the center through hole 55 by the groove 52 of the center rod 24 at the movement limit position. The central through hole 55 is a low pressure side through hole that communicates with an exhaust port or the like that is open to the atmosphere.

Packings 56 and 57 are fitted to left and right portions of the center rod 24 through the groove 52, and these packings 56 and 57 are fitted.
57 is slid in a state of being closely fitted to the rod fitting hole 23.

Next, the operation and effect of this embodiment will be described.

For example, when the working fluid is alternately supplied to and discharged from the left and right drive chambers 25 and 26 by switching the internal movable valve body of the switching valve 33 at a constant cycle by using a solenoid that is switched by a timer. The diaphragms 21 and 22 alternately expand and contract in conjunction with the center rod 24 to repeatedly drive the left and right driving chambers.
25 and 26 alternately repeat the expansion and contraction of the volume, and the left and right pump chambers 27 and 28 alternately repeat the contraction and expansion of the volume.

Due to the reduced volume of the drive chambers 25 and 26, the pump chamber 2
When the capacity of the pump chambers 7 and 28 is increased, the fluid to be transferred is sucked from the suction port 44 into the pump chambers 27 and 28 via the check valves 37 and 38 on the suction side. 27,
When the volume of the container 28 is reduced, the fluid to be transferred is discharged from the pump chambers 27 and 28 through the discharge ports 46 via the check valves 41 and 42 on the discharge side.

As shown in FIG. 1, when the diaphragms 21 and 22 and the center rod 24 are operated to the dead center of the left operation limit position, that is, the stroke end, the drive chamber side through hole provided in the pump body member 12 is provided. 53 and the low-pressure side through-hole 55 communicate with each other through the groove 52 provided in the center rod 24, so that at this time, even if the working fluid is continuously supplied from the switching valve 33 to the drive chamber 25 on the left side, the working fluid is Since it escapes from the left through hole 53 to the low pressure side through hole 55 via the groove 52 and is discharged into the atmosphere or the like, it is possible to prevent excessive working fluid pressure from acting on the left drive chamber 25, and rather to prevent The driving chamber 25 can be decompressed.

For this reason, excessive working fluid pressure does not act on the left diaphragm 21, and the central connecting portion of the opposite diaphragm 22 does not strongly interfere with the pump body member 12, and the diaphragms 21, 22 are not affected.
Rupture or damage to component parts can be prevented.

When the diaphragms 21 and 22 and the center rod 24 move to the right in FIG. 1, the right through hole 54 and the center through hole 55 communicate with each other through the groove 52 of the center rod 24, and the right driving chamber 26
Can be decompressed.

The diaphragms 21 and 22 may be not only diaphragms but also other diaphragms. That is, the present pump device can be applied to a reciprocating pump (a diaphragm pump, another diaphragm pump, or the like) that operates by a pressure difference of a working fluid using a diaphragm. Further, the present invention can be applied to a single diaphragm using the diaphragm 21 or 22 alone. In addition, this device
It is also applicable to piston pumps.

Thus, the diaphragm in the reciprocating pump
When the working fluids 21 and 22 are located at the dead center, that is, at the stroke end, the working fluid is restricted or discharged to the low pressure side to reduce the pressure in the driving chambers 25 and 26, so that the expansion force of the diaphragms 21 and 22 and the pump components are reduced. The acting load can be reduced to prevent the life of the parts from being shortened or damaged.

In addition, since the load on the pump component is reduced, the required component strength can be set low, and the material of the pump component such as the pump body 11 can be formed of a nonmetal, for example, plastic. As a result, the weight can be reduced and the corrosion resistance can be improved.

Further, even when the working fluid is continuously supplied from the switching valve 33 to the drive chambers 25 and 26 when the diaphragms 21 and 22 have moved to the stroke end, the chamber pressure of the drive chambers 25 and 26 is controlled by the valve mechanism 51. There is no problem because the pressure is reduced. Therefore, when the switching valve 33 is switched at regular intervals by a timer or the like, the timer setting time may be set slightly longer than the time required until the stroke end of the diaphragms 21 and 22. Easy.

[0028]

According to the first aspect of the invention, when the diaphragm operates to the operation limit position, a valve mechanism different from the switching valve for controlling the supply and discharge of the working fluid to and from the drive chamber operates, and the drive chamber is operated. Is released to the low pressure side, so that a failure of the pump device due to excessive working fluid pressure acting on the drive chamber can be prevented. In addition, since the load on the pump components is reduced, the required component strength can be set low, and the pump components can be made of a non-metallic material to reduce the weight.

According to the second aspect of the invention, the valve mechanism can be simply constituted by the groove of the center rod and the through hole of the pump body.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a pump device according to the present invention.

FIG. 2 is a cross-sectional view showing an example of a conventional pump device.

FIG. 3 is a cross-sectional view showing an operation state of a conventional pump device.

[Explanation of symbols]

 11 Pump body 21, 22 Diaphragm 24 Center rod 25, 26 Drive chamber 27, 28 Pump chamber 33 Switching valve 51 Valve mechanism 52 Groove 53, 54 Drive chamber side through hole 55 Low pressure side through hole

Claims (2)

[Claims] 1. A pump body, a diaphragm movably provided in the pump body, a driving chamber provided on one side of the diaphragm for supplying and discharging a working fluid, and a fluid to be transferred provided on the other side of the diaphragm. Pump chamber into and out of which, a switching valve that changes the volume of the pump chamber by controlling the supply and discharge of working fluid to and from the driving chamber, and the pressure in the driving chamber to the low pressure side without passing through the switching valve at the operation limit position of the diaphragm A pump device comprising a relief valve mechanism. 2. A pair of diaphragms are connected by a center rod slidably fitted to the pump body, and a valve mechanism is provided with a groove provided in the center rod and a movement limit position formed in the pump body. The pump device according to claim 1, further comprising a through hole on the drive chamber side and a through hole on the low pressure side, which are mutually communicated by the groove of the center rod.