JP2777704B2 - Bellows metering pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bellows type metering pump suitable for transferring a fluid, such as a chemical solution or pure water, which is required to be metered.

[0002]

2. Description of the Related Art As a bellows type metering pump of this kind,
Conventionally, the one disclosed in Japanese Utility Model Publication No. 61-35750 is known. FIG. 5 shows the structure of a main part of a conventional bellows type metering pump disclosed in the above-mentioned publication. A pump body 32 having a suction hole 30 and a discharge hole 31 for a fluid to be transferred is formed in a cylindrical shape. Forming a protrusion 33,
On the central axis of the cylindrical protrusion 33, a flow hole 34 having one end communicating with the suction hole 30 and the other end opening at the tip end surface of the cylindrical protrusion 33 is formed. Is a base end of the cylindrical protrusion 33 at an inner end position of an annular gap 36 between an inner circumference of a bellows 35 disposed on an outer circumference of the cylindrical protrusion 33 and an outer peripheral surface of the cylindrical protrusion 33. An opening is connected to an annular groove 37 formed on one side surface of the pump body 32 so as to surround the peripheral portion.

Further, one end of the bellows 35 abuts on the center of one side surface of the pump body 32 and is fixed by a fixing plate 38, and the other end of the bellows 35 is closed by a closing plate 40 via a seal plate 39. At the same time, it is held by the closing plate 40 and the mounting plate 41.

According to the conventional bellows type metering pump configured as described above, the suction hole in which the bellows 35 is extended by the reciprocating drive device opens the flow hole 34 to make the inside of the bellows 35 negative pressure. The fluid to be transferred is sucked into the annular gap 36 through the path of the suction hole 30 and the circulation hole 34.
Further, the inside of the bellows 35 is pressurized by the discharge process of contracting the bellows 35, and the fluid to be transferred sucked into the annular gap 36 is discharged through the path of the annular groove 37 and the discharge hole 31. That is, the bellows 35 is driven by the reciprocating drive device.
It is said that the fluid to be transferred is intermittently discharged by expanding and contracting the ink, and the discharge amount is determined by the discharge stroke (discharge stroke), so that quantitative transfer can be expected.

However, the annular gap 36 and the annular groove 37
In the fluid inside, a force that flows toward the discharge hole 31 by inertia acts even after the end of the discharge stroke. In addition, at the end position of the discharge step, the seal plate 39 abuts on one end face of the bellows 35 and the tip end face of the cylindrical projection 33 with a relatively large area, respectively, to close the annular gap 36 and the flow hole 34. Therefore, the contact pressure is low and high sealing performance cannot be expected. Therefore, after the end of the discharge stroke, the fluid to be transferred in the annular gap 36 and the annular groove 37 is discharged from the discharge hole 3.
1 and flows out toward the annular gap 36
Even if the inside of the inner space is made negative pressure, the surface pressure of the contact portion cannot be increased and the sealing cannot be performed reliably by the negative pressure. 34
The fluid to be transferred continues to flow into the annular gap 36, and the flow out of the discharge hole 31 is continued even after the end of the discharge stroke, thereby preventing the fixed amount transfer.

On the other hand, when the operation of the bellows type metering pump is stopped for a relatively long time during maintenance or the like, it is necessary to prevent the outflow of the fluid to be transferred for the above-mentioned reason. Therefore, the intersection of the suction hole 30 and flow holes 34 extending to the opposite side of the circulation hole 34, here, for example, with connecting an outlet of the flow control valve 43 of the needle valve, the inlet of the flow control valve 43 And discharge hole 31
Are connected by a bypass passage 42 so that the fluid to be transferred flowing out of the discharge hole 31 is returned from the bypass passage 42 to the circulation hole 34 even after the end of the discharge stroke, or is prevented from flowing out to the discharge pipe connected to the discharge hole 31. It is necessary to interpose a valve, and there is a disadvantage that the structure of the attached piping system becomes complicated accordingly.

[0007]

That is, in the conventional bellows type metering pump, since the sealing property at the end position of the discharge stroke is low, the flow of the fluid to be transferred continues even after the end of the discharge stroke. However, there is a drawback that the quantitative transfer is hindered. For this reason, the structure of the attached piping system was complicated. Therefore, an invention according to claim 1 and claim 2, wherein, by increasing the suction side of the seal of the discharge stroke end position, and reliably prevent the outflow of the transport fluid after the discharge stroke ends, the discharge stroke A bellows-type metering pump that can accurately transfer a fixed amount at the determined discharge rate, simplifies the structure of the attached piping system by eliminating the need for a flow control valve and a bypass passage or an outflow prevention valve, etc. Is intended to provide
You.

[0008]

According to a first aspect of the present invention, there is provided a bellows type metering pump in which a suction port and a discharge port for a transfer fluid are formed and communicate with the suction port. A pump body having a columnar projecting portion having a passage formed therein and having the discharge hole opened around a base end of the columnar projecting portion; and a pump body provided around the columnar projecting portion and having one end opening formed at the discharge hole. A discharge stroke end position at which the other end closing portion approaches the tip end surface of the columnar protrusion and closes the outlet of the passage, and a tip end surface of the columnar protrusion while being fixed to the pump body in communication with the opening of the column. a bellows which expands and contracts moves over between the intake stroke end position remote from the reciprocating drive device for extending and retracting the bellows is connected to the bellows, the inlet of the suction holes and
It is located at the outlet of the discharge port, and the suction direction and discharge
A spring-type check valve that allows only the flow in the outflow direction, and the distal end surface of the columnar projection is opposed to the columnar projection at the other end closed portion of the bellows at the discharge stroke end position. locally abuts annular seal projections prior to the surface
And it is characterized in that is provided along the outer periphery of the outlet of the serial passage. The bellows-type metering pump according to the second aspect of the present invention has a columnar projection having a passage formed with a suction hole and a discharge hole for a transfer fluid and communicating with the discharge hole. A pump body having the suction hole opened around the base end of the pump body, the pump body being provided around the columnar protrusion, and one end opening communicating with the opening of the suction hole and being fixed to the pump body; The other end closing portion approaches the tip end surface of the columnar protrusion and expands / contracts between a discharge stroke end position where the entrance of the passage is closed and a suction stroke end position separated from the tip end surface of the columnar protrusion. A bellows, a reciprocating drive device connected to the bellows to extend and retract the bellows ,
The transfer fluid is located at the inlet of the suction port and the outlet of the discharge port.
That allow flow only in the suction and discharge directions
A ring-type check valve, and a tip end surface of the columnar protrusion.
In the discharge stroke end position, an annular seal projection is provided along the outer periphery of the entrance of the passage so as to locally abut on a surface facing the columnar projection at the other end closing portion of the bellows. It is characterized by the following.

According to the first aspect of the present invention, the inside of the bellows is made negative pressure by the suction process for expanding the bellows, and the fluid to be transferred is sucked into the discharge hole through the suction hole and the passage. In addition, the inside of the bellows is pressurized by the discharge process of contracting the bellows, and the fluid to be transferred sucked into the discharge holes is discharged. That is, the fluid to be transferred is intermittently discharged by expanding and contracting the bellows, and the discharge amount can be determined by the discharge stroke. on the other hand,
At the end position of the discharge stroke, the annular sealing projection projecting along the outer periphery of the outlet of the passage locally abuts on the surface facing the columnar projection at the other end closing portion of the bellows. The surface pressure of the part is increased, and the outlet of the passage can be closed with high sealing performance. Therefore, even working force flowing from the discharge hole to be transported fluid by the inertia after the ejection stroke end, because the transfer fluid in the passage can be prevented from flowing toward the discharge hole, the transfer at the time of the discharge stroke ends It is possible to reliably prevent the fluid from flowing out.

According to the second aspect of the present invention, the inside of the bellows is made negative pressure by the suction stroke for expanding the bellows, and the fluid to be transferred is sucked into the passage and the discharge hole through the suction hole and the passage. Further, the inside of the bellows is pressurized by a discharge process for contracting the bellows, and the fluid to be transferred sucked into the passage and the discharge hole is discharged. That is, the fluid to be transferred is intermittently discharged by expanding and contracting the bellows, and the discharge amount can be determined by the discharge stroke. On the other hand, at the discharge stroke end position, the annular seal protrusion projecting along the outer periphery of the entrance of the passage locally abuts on the surface facing the columnar protrusion at the other end closing portion of the bellows. The surface pressure of the contact portion is increased, and the entrance of the passage can be closed with high sealing performance. Therefore, even when a force flowing out of the discharge hole acts on the fluid to be transferred due to inertia after the end of the discharge stroke, the outflow of the transferred fluid can be reliably prevented at the end of the discharge stroke .

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; FIG. 1 is a longitudinal sectional view showing an embodiment of the first aspect of the present invention. In this figure, a disc-shaped pump body 1 is formed with a suction hole 2 for a fluid to be transferred and a discharge hole 3 for a fluid to be transferred, and a cylindrical projection 17 is formed at one end of the pump body 1 in the axial direction. It is provided integrally. The pump body 1 and the columnar projection 17 are formed of PTFE (polytetrafluoroethylene plastic resin) or PFA (perfluoroalkoxy fluororesin). The suction hole 2 extends to near the center line of the cylindrical projection 17, and its outlet communicates with a passage 18 formed on the center line.
Is opened at the tip of the cylindrical projection 17. Further, an annular groove 19 is formed on one side surface of the pump body 1 surrounding the outer periphery of the base end of the columnar projecting portion 17, and the inlet of the discharge hole 3 is opened in the annular groove 19.

A suction unit 4 is provided in the suction hole 2.
A discharge unit 5 is provided in the discharge hole 3. The suction unit 4 and the discharge unit 5 are respectively
A spring-type check valve 8 pressed and fixed by a holding nut 7 and a valve retainer 6 is provided. The spring-type check valve 8 includes a check valve body 8A and a spring 8B. The check valve 8 of the suction unit 4 allows only the flow in the direction of the suction hole 2, and the flow in the direction opposite to the suction hole 2. The check valve 8 of the discharge unit 5 is configured to allow only the flow in the discharge direction (the direction opposite to the discharge hole 3) and to block the flow in the direction of the discharge hole 3. .

A bellows 9 having a fold 9A is arranged on the outer periphery of the columnar projection 17. The open one end 9B of the bellows 9 is in contact with one side surface of the pump body 1 and is fixed to the pump body 1 via a fixing plate 10, and the open other end 9C is closed via a seal plate 11. 12 and is sandwiched between the closing plate 12 and the mounting plate 13. In addition, the closing plate 12 is screwed into the ring body 14 that holds down the mounting plate 13.

On the other hand, on the tip end surface of the cylindrical projection 17 ,
As also shown in FIG. 2, along the outer periphery of the outlet of the passage 18
Thus, an annular seal projection 16 is provided. The cross-sectional shape of the annular seal projection 16 is trapezoidal. Therefore, the annular seal projection 16 is provided with the bellows 9.
At the end position of the discharge stroke of the bellows 9, the closed surface of the bellows 9 is locally in contact with the front surface 17 t of the columnar projection 17, that is, the inner surface of the seal plate 11. In addition, 1 in the figure
Reference numeral 5 denotes a reciprocating body such as a piston rod which is reciprocated in the axial direction by a driving source such as a fluid cylinder (not shown). The closing plate 12 is connected to the tip of the reciprocating body 15 so that the reciprocating body 15 reciprocates. Bellows 13 by moving
Is designed to expand and contract.

A passage 6a is formed through the center line of the valve holder 6 of the suction unit 4, and a passage 6a is formed through the center line of the valve holder 6 of the discharge unit 5. At the inlet side of the passage 6a of the valve retainer 6 in the suction unit 4, an inner ring 21A is press-fitted into one end of a resin-supplied fluid supply pipe 20A to expand the diameter of the fluid supply pipe 20A. The inner ring 21A is screwed into the cylindrical receiving port 22A for inserting the end of the fluid supply pipe 20A whose diameter has been enlarged by the above and the outer end of the valve retainer 6, and the fluid supply pipe 20A.
The fluid pipe 20A to be transferred is connected via a pipe joint 24A consisting of a pressing ring 23A which presses from outside the tube to give a sealing force. In addition, at the outlet side of the passage 6a of the valve retainer 6 in the discharge unit 5, a transferred fluid discharge pipe 20 made of resin is provided.
B, an inner ring 21B press-fitted into one end of the fluid discharge pipe 20B to expand the diameter of the fluid discharge pipe 20B, a cylindrical socket 22B for inserting the end of the fluid discharge pipe 20B expanded by the inner ring 21B, and a valve. A pipe joint 24 comprising a pressing ring 23B which is screwed into the outer end of the presser 6 and presses the inner ring 21B from outside the fluid discharge pipe 20B to apply a sealing force.
The transferred fluid discharge pipe 20B is connected via B.
In the figure, reference numeral 26 denotes a support table, and the pump body 1 and the reciprocating body 1
5 and are supported.

In the above configuration, the bellows 9 expands and contracts by reciprocating the reciprocating body 15 with a predetermined stroke in the directions indicated by arrows XY in FIG. 1 by driving the driving source. The inside of the bellows 9 is made negative pressure by the suction stroke (the direction of the arrow X) for expanding the bellows 9. Therefore, the transferred fluid is
Through the passage of the fluid supply pipe 20A to be transferred, the passage 6a of the valve retainer 6, the check valve 6A, the suction hole 3, and the passage 18, the air is sucked into the space surrounding the cylindrical projection 17 in the internal space of the bellows 9. . Further, the inside of the bellows 9 is pressurized by a discharge process (arrow Y direction) for contracting the bellows 9.
As a result, the fluid to be transferred in the space is pushed into the discharge hole 3, and is discharged to the transferred fluid discharge pipe 20B through the path of the check valve 6B and the passage 6a of the valve retainer 6. That is, the fluid to be transferred is intermittently discharged by expanding and contracting the bellows 9, and the discharge amount can be determined by the discharge stroke.

At the end position of the discharge stroke , an annular seal projection 16 protruding along the outer periphery of the outlet of the passage 18 is opposed to the tip end face 17t of the columnar projection 17 at the other end closing portion of the bellows 9. Surface, that is, the inner surface of the seal plate 11 is locally abutted. Since the cross-sectional shape of the seal protrusion 16 is formed in a trapezoidal shape, the top having a small area is the seal plate 1.
As a result, the surface pressure of the contact portion is increased and the outlet of the passage 18 can be closed with high sealing performance. Therefore, even if a force flowing out of the discharge hole 3 acts on the transferred fluid due to inertia after the end of the discharge stroke, the transferred fluid in the passage 18 can be prevented from flowing toward the discharge hole 3. As a result, it is possible to reliably prevent the fluid to be transferred from flowing out, and to accurately perform the quantitative transfer with the discharge amount determined by the discharge stroke. In addition, even when the operation of the bellows type metering pump is stopped for a relatively long time during maintenance or the like, it is necessary to prevent the transferred fluid from leaking to the transferred fluid discharge pipe 21B during the stop.
The transfer type discharge pipe 2 is prevented by the
It is not necessary to provide a flow control valve and a bypass passage or an outflow prevention valve in 0B. Therefore, the structure of the attached piping system can be simplified as compared with the conventional bellows type metering pump.

FIG. 3 is a longitudinal sectional view showing an embodiment of the second aspect of the present invention. The same parts as those of the embodiment of the invention described in claim 1 described with reference to FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description of the structure is omitted. Invention of claim 2, wherein, as shown in FIG. 4, column
Along the outer periphery of the entrance of the passage 18 communicating with the discharge hole 3 at the distal end surface of the protruding portion 17, at the discharge stroke end position, the opposite surface of the other end closing portion of the bellows 9 to the columnar protrusion 17; An annular seal protrusion 16 is provided on the inner surface of the seal 11 so as to abut locally.

With this configuration, the bellows 9 expands and contracts by reciprocating the reciprocating body 15 with a predetermined stroke in the directions indicated by arrows XY in FIG. 3 by driving the driving source.
The inside of the bellows 9 is made negative pressure by the suction stroke (the direction of the arrow X) for expanding the bellows 9. Therefore, the transferred fluid is supplied to the transferred fluid supply pipe 20A and the passage 6 of the valve retainer 6.
a, through the passage of the check valve 6A, the suction hole 3, and the passage 18, the air is sucked into the space surrounding the cylindrical projection 17 in the internal space of the bellows 9. Further, the inside of the bellows 9 is pressurized by a discharge process (arrow Y direction) for contracting the bellows 9. As a result, the fluid to be transferred in the space is discharged from the discharge hole 3
And the passage 6a of the check valve 6B and the valve retainer 6
Is discharged to the transferred fluid discharge pipe 20B. That is, the fluid to be transferred is intermittently discharged by expanding and contracting the bellows 9, and the discharge amount can be determined by the discharge stroke.

At the discharge stroke end position, an annular sealing projection 16 protruding along the outer periphery of the entrance of the passage 18 is opposed to the tip end face 17t of the columnar projection 17 at the other end closing portion of the bellows 9. The surface, that is, the sealing plate 11 is locally contacted. Since the cross-sectional shape of the seal projection 16 is formed in a trapezoidal shape, the top having a small area comes into contact with the seal plate 11, so that the surface pressure of the contact portion is increased and the sealing portion has high sealing performance. The exit of the passage 18 can be blocked. Therefore, the inertia after the ejection stroke ends even force acts flowing from the discharge port 3 to the transfer fluid, and reliably prevent the outflow of the transport fluid during discharge stroke ends, the discharge amount determined by the discharge stroke Accurate quantitative transfer can be performed. Further, even when the operation of the bellows type metering pump is stopped for a relatively long time during maintenance or the like, the transferred fluid is not transferred during the stop.
Spring type check valve 8 prevents leakage to 1B side
To so, it is not necessary to provide such a flow control valve and the bypass passage or the outflow valve to be transfer fluid discharge pipe 20B.
Therefore, the structure of the attached piping system can be simplified as compared with the conventional bellows type metering pump.

In the above embodiment, the pump body 1 is provided with the cylindrical projection 2 integrally provided. However, the pump body 1 is provided with the prismatic projection 2 integrally. It may be.

[0022]

As described above, according to the first aspect of the present invention, the outer periphery of the outlet of the suction hole is provided at the end position of the discharge stroke.
Since the annular seal protrusion projecting along the surface locally contacts the surface of the bellows opposed to the columnar protrusion at the other end closed portion, the surface pressure of the contact portion is increased to provide high sealing performance. Thus, the inlet of the discharge hole can be closed. Therefore, even working force flowing from the discharge hole to be transported fluid by the inertia after the ejection stroke end, because the transfer fluid in the passage can be prevented from flowing toward the discharge hole, the transfer at the time of the discharge stroke ends The outflow of the fluid can be reliably prevented, and the quantitative transfer can be accurately performed with the discharge amount determined by the discharge stroke. In addition, even when the operation of the bellows type metering pump is stopped for a relatively long time during maintenance or the like, the transferred fluid does not leak during the stop, so that it is not necessary to provide a flow control valve and a bypass passage or an outflow prevention valve. . Therefore, the structure of the attached piping system can be simplified as compared with the conventional bellows type metering pump. Claim 2
According to the invention described above, the annular seal protrusion protruding along the outer periphery of the inlet of the discharge hole at the discharge stroke end position is locally provided on the surface facing the columnar protrusion at the other end closing portion of the bellows. Therefore, it is possible to increase the surface pressure of the contact portion and to have a high sealing property to close the inlet of the discharge hole. Therefore, even working force flowing from the discharge hole to be transported fluid by the inertia after the ejection stroke end, can be prevented reliably outflow of the transport fluid during discharge stroke ends, the discharge amount determined by the discharge stroke Accurate quantitative transfer can be performed. In addition, even when the operation of the bellows type metering pump is stopped for a relatively long time during maintenance or the like, the transferred fluid does not leak during the stop, so that it is not necessary to provide a flow control valve and a bypass passage or an outflow prevention valve. . Therefore, the structure of the attached piping system can be simplified as compared with the conventional bellows type metering pump.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the invention described in claim 1;

FIG. 2 is an enlarged view showing a main part of the invention according to claim 1;

FIG. 3 is a longitudinal sectional view showing one embodiment of the invention described in claim 2;

FIG. 4 is an enlarged view showing a main part of the invention according to claim 2;

FIG. 5 is a longitudinal sectional view showing a main part of a conventional bellows type metering pump.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Pump body 2 Suction hole 3 Discharge hole 9 Bellows 9B One end of bellows 9C The other end of bellows 11 Seal plate (other end closed part of bellows) 15 Reciprocating body (reciprocating drive device) 16 Annular seal projection 17 Columnar shape Projection (columnar projection) 17t Tip surface of columnar projection 18 Passage

Claims (2)

(57) [Claims] An apparatus has a columnar protrusion formed with a suction hole and a discharge hole for a transfer fluid and having a passage communicating with the suction hole, and the discharge hole is opened around a base end of the columnar protrusion. Pump body, provided around the columnar protrusion, and one end opening is fixed to the pump body in communication with the opening of the discharge hole, and the other end closing part is a tip of the columnar protrusion. A bellows that expands and contracts between a discharge stroke end position that approaches the surface and closes the outlet of the passage and a suction stroke end position that is separated from the distal end surface of the columnar protrusion; and a reciprocating drive device for extending and retracting the bellows, said suction holes
How to inhale the transfer fluid, located at the inlet and outlet of the discharge port
Spring type that only allows flow in the discharge and discharge directions
A non-return valve, and an annular seal projection locally provided on a distal end surface of the columnar projection at an end of the discharge stroke at a position opposite to the columnar projection at the other end closing portion of the bellows. A bellows-type metering pump, wherein a portion is provided along an outer periphery of an outlet of the passage . 2. A method according to claim 1, further comprising a columnar projection formed with a suction hole and a discharge hole for the transfer fluid and having a passage communicating with the discharge hole, and the suction hole being opened around a base end of the columnar protrusion. And a pump body provided around the columnar protrusion, one end opening of which is fixed to the pump body in communication with the opening of the suction hole, and the other end of which is closed at the tip of the columnar protrusion. A bellows that expands and contracts between a discharge stroke end position that approaches the surface and closes the entrance of the passage and a suction stroke end position that is separated from the tip end surface of the columnar protrusion; and a reciprocating drive device for extending and retracting the bellows, said suction holes
How to inhale the transfer fluid, located at the inlet and outlet of the discharge port
Spring type that only allows flow in the discharge and discharge directions
A non-return valve, and an annular seal projection locally provided on a distal end surface of the columnar projection at an end of the discharge stroke at a position opposite to the columnar projection at the other end closing portion of the bellows. A bellows-type metering pump, wherein a portion is provided along an outer periphery of an inlet of the passage .