JP2573154B2 - 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 used for transferring a fluid, such as a chemical solution or pure water, for which a fixed amount transfer without stagnation is desired.

[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. 3 shows a structure of a main part of a conventional bellows type metering pump disclosed in the above-mentioned publication, in which a pump body 32 having a suction port 30 and a discharge port 31 for a fluid to be transferred is formed in a cylindrical shape. Forming a 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 on the inner central axis of the cylindrical protrusion 33, and the discharge hole is formed at the other end. The hole 31 is formed at the inner end position of the annular gap 36 between the inner periphery of the bellows 35 disposed on the outer periphery of the cylindrical protrusion 33 and the outer peripheral surface of the cylindrical protrusion 33. Pump body 3 surrounding the base end
An opening is connected to an annular groove 37 formed on one side surface of each of the two.

Next, a description will be given of a fluid transfer operation by the conventional bellows type metering pump having the above-described structure. By expanding and contracting the bellows 35 via the reciprocating drive device, when the bellows 35 is extended, the flow hole 34 is opened and the bellows 3 is opened.
5 has a negative pressure, the fluid to be transferred is sucked into the annular gap 36 through the suction hole 30 and the flow hole 34 in a fixed amount, and the flow hole 34 is closed at the time of contraction. The fluid to be transferred sucked into the annular gap 36 is pressurized by the bellows 35, pushed out from the annular groove 37 into the discharge hole 31, and discharged outward.
The fluid to be transferred is intermittently transferred for each fixed amount.

[0004]

The conventional bellows type metering pump having the above-described structure has a large space (annular gap 36) between the bellows 35 and the cylindrical projection 33 of the pump body 32. However, as the bellows 35 contracts, the fluid to be transferred sucked and stored in the annular gap 36 is discharged through the annular groove 37 in a state of being gathered into the single discharge hole 31 in a cylindrical shape. Since a portion having poor fluidity and substitution is generated at the base end of the protruding portion 33, a part of the fluid to be transferred is likely to remain. In other words, it has a pump structure with many fluid pools,
Thereby, even if the actual discharge amount of the fixed value is secured, a part of the fluid to be transferred stays in the pump for a long period of time, and as a result, especially for the transfer of a fluid such as a chemical which is likely to deteriorate in quality. There is a problem that it is not preferable from the viewpoint of quality maintenance.

[0005] The present invention has been made in view of the above-described circumstances, and enables accurate and quantitative transfer of a fluid to be transferred with a simple configuration.
It is another object of the present invention to provide a bellows-type metering pump capable of maintaining good quality of a fluid to be transferred without a fluid pool inside the pump.

[0006]

In order to achieve the above-mentioned object, a bellows type metering pump according to the present invention has a protrusion having a circular cross section, and is opened at a base end of the circular protrusion. A groove-like passage communicating with the suction hole is formed on a side surface of the protrusion from an opening of the suction hole to a tip end of the circular protrusion, and a suction hole for the fluid to be transferred is formed,
A pump body in which a discharge hole for a fluid to be transferred is formed by opening the tip end surface of the circular protrusion, and disposed on the outer periphery of the circular protrusion, one end of which is fixed to the pump body. And a bellows that extends and contracts between a compressed end position in which the other end closing portion abuts on the distal end surface of the circular protrusion and an extended end position separated from the distal end surface of the circular protrusion. And a reciprocating drive connected to the bellows to extend and retract the bellows.
And a small number of circular protrusions in the pump body
At least the outer peripheral surface of the part corresponding to the movable part
Along the direction, a tapered surface with a smaller diameter toward the tip
It is characterized by that.

[0007]

According to the present invention, the suction hole for the fluid to be transferred is opened at the base end of the circular projection formed in the pump body, and the projection extends from the opening to the tip of the circular projection. A groove-shaped passage communicating with the suction hole is formed on the side surface of the part, and the discharge hole for the fluid to be transferred is formed in a circular protrusion, so that the bellows and a part of the pump body are circular. It is possible to greatly reduce the volume of space between the protrusion and the conventional one. In addition, since the discharge hole is opened at the end face of the distal end of the circular protrusion, the flow of the fluid to be transferred at the time of discharge becomes smooth, whereby the remaining of the fluid to be transferred at the time of discharge, that is, the fluid stagnation, Absolutely, accurate transfer of the fixed quantity is ensured, and there is no deterioration in the quality of the fluid.

[0008] Moreover, of the outer peripheral surface of the circular protrusion of the pump body, is formed in a tapered surface the outer peripheral surface of the portion corresponding to the movable portion of the bellows is small enough tip side along the axial direction Therefore, even if the front end side of the bellows slightly oscillates during the expansion and contraction operation of the bellows, there is no operation failure such that the front end portion is caught on the outer peripheral surface of the protruding portion,
A smooth pump operation can always be maintained reliably.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a bellows type metering pump according to one embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a disk-shaped pump body, and a projection 2 having a circular cross section is integrally formed at one end in the axial direction. are continuously provided, out of the outer peripheral surface of the circular protrusion 2, the outer circumferential surface 2a of the distal part corresponding to the movable portion of the bellows to be described later, a smaller diameter as the distal end side along the axial direction The outer peripheral surface 2b of the base end portion corresponding to the tapered surface and corresponding to the immovable portion of the bellows is formed as a straight cylindrical surface along the axial direction.

Reference numeral 3 denotes a suction hole for the fluid to be transferred, which is formed at a position deviated from the center axis of the pump body 1 (see FIG. 2). As shown in FIG. 2, the side surface of the circular projection 2 from the opening 3a to the tip end surface 2t of the circular projection 2 is open at the base end of the portion 2. U
A U-shaped groove-shaped passage 4 is formed so as to communicate with the suction hole 3. The base end of the suction hole 3 is connected to the pump body 1.
Is connected via a ball-type check valve 6A to one end of an inner flow path 5a of an elbow-type joint main body 5A screwed into the main body. An inner ring 8A press-fitted into one end of a resin-transferred fluid pipe 7A to expand the diameter of the fluid pipe 7A is inserted into the other end of the inner flow path 5a of the elbow joint body 5A. The cylindrical ring 9A for inserting the end of the fluid pipe 7A whose diameter has been expanded by 8A and the one end of the joint main body 5A are screwed to press the inner ring 8A from the outside of the fluid pipe 7A to seal. The transferred fluid pipe 7A is connected via a pipe joint 12A composed of a pressing wheel 10A for applying a force.

Reference numeral 11 denotes a discharge hole for the fluid to be transferred, which is formed at a position deviated to the side opposite to the suction hole 3 with respect to the center axis of the pump body 1.
Has an opening at a tip end face 2t of the circular projecting portion 2, and a base end of the discharge hole 11 has an inner flow passage of an elbow joint body 5B screwed to the pump body 1. 5b is connected to one end via a ball check valve 6B. The other end of the inner flow path 5b of the elbow joint body 5B is press-fitted into one end of a pipe joint 12B having the same configuration as the above-described pipe joint 12A, that is, one end of a resin-transferred fluid pipe 7B. An inner ring 8B for expanding the diameter of the fluid pipe 7B and a cylindrical receiving port 9 for inserting an end of the fluid pipe 7B expanded by the inner ring 8B.
B and the fluid pipe 7B to be transferred are connected via a pipe joint 12B consisting of a push ring 10B which is screwed to one end of the joint main body 5B and presses the inner ring 8B from outside the fluid pipe 7B to apply a sealing force. Have been.

A bellows 13 has a pleat 13a. The bellows 13 is arranged on the outer periphery of the circular projection 2 and one end thereof is in contact with one side surface of the pump body 1 to fix the fixing plate 14a.
And the other end portion has a tip end surface 2 of the circular protrusion 2 as the bellows 13 expands and contracts.
A closing portion 13b that comes into contact with and separates from t is provided. Reference numeral 15 denotes a reciprocating body such as a piston, which is reciprocated in the axial direction by a reciprocating drive device such as a fluid cylinder (not shown). The center of the closed portion 13b of the bellows 13 is connected to the tip of the reciprocating body 15. The bellows 13 expands and contracts by the reciprocating movement of the reciprocating body 15.

In the bellows type metering pump having the above-described structure, the reciprocating body 15 is connected to the reciprocating body 15 via a reciprocating drive device as shown in FIG.
When the bellows 35 is extended and contracted by reciprocating in the directions indicated by arrows X and Y in FIG.
Is separated from the tip end face 2t of the circular projection 2 and the tip of the U-shaped groove-shaped passage 4 is opened, so that the internal space of the bellows 13 becomes negative pressure. The transfer fluid is the internal flow path 5a of the elbow joint body 5A, the check valve 6
A, the groove-shaped passage 4 via the suction hole 3 and the closed portion 13b
A certain amount is sucked into the space between the tip end face 2t of the circular projection 2 and the tip end face 2t.

Next, when the bellows 13 contracts, the closing part 13b gradually moves closer to the tip end face 2t of the circular projection 2 and finally the tip end face 2t of the circular projection 2.
will come into contact with t. During this time, the transferred fluid sucked into the space is pressurized by the bellows 13, so that the transferred fluid is pushed into the discharge hole 11, and the check valve 6B, The fluid is discharged into the other fluid pipe 7B via the internal flow path 5b of the elbow joint body 5B. In this manner, the fluid to be transferred is intermittently transferred from the one fluid pipe 7A to the other fluid pipe 7B at every fixed amount with the expansion and contraction operation of the bellows 13.

By the way, as in the above embodiment, the suction hole 3 for the fluid to be transferred is opened at the base end of the circular projecting portion 2 of the pump body 1, and the distal end of the circular projecting portion 2 is opened from the opening 3a. A groove-shaped passage 4 communicating with the suction hole 3 is formed on a side surface of the protruding portion 2 up to the portion, and a discharge hole 11 for the fluid to be transferred is formed in the circular protruding portion 2, and the end thereof protrudes. Since the opening is formed at the end face 2t of the distal end of the portion 2, the bellows 13 and the circular projection 2 which is a part of the pump body 1 are formed.
The volume between them is very small in volume, and the fluid pool is reduced. Therefore, the fluidity and displacement of the fluid to be transferred at the time of discharge accompanying the contraction of the bellows 13 are improved,
There is almost no decrease in the actual discharge amount due to fluid retention,
The quantitative property is improved, and the fluid replacement time is shortened, so that the quality is extremely reduced.

In addition, when the bellows 13 expands and contracts, the tip end side of the bellows 13 often slightly oscillates. In this case, if the inner diameter of the bellows 13 and the outer diameter of the protruding portion 2 are substantially equal to each other and are formed in a cylindrical shape, the bellows 13
When the tip side of the circular projection 2 is liable to run out, the tip is likely to be caught on the outer peripheral surface of the protruding portion 2. However, as in the present embodiment, the bellows Outer peripheral surface 2 of portion corresponding to 13 movable parts
a is formed on a tapered surface that becomes smaller in diameter toward the tip end along the axial direction . Therefore , even if the tip end of the bellows 13 slightly shakes during the expansion and contraction operation of the bellows 13, the tip end of the projection 2 It is possible to eliminate the occurrence of operation trouble such as being caught on the outer peripheral surface, and to perform a smooth expansion / contraction operation.

In the above-described embodiment, the groove-shaped passage 4 formed on the side surface of the protruding portion 2 in communication with the suction hole 3 has a substantially U-shaped cross section. Good.

[0018]

As described above, according to the present invention, the suction port for the fluid to be transferred is opened at the base end of the circular cross-sectional projection provided on the pump body, and the circular projection is formed from the opening. A groove-shaped passage communicating with the suction hole is formed on the side surface of the protruding portion up to the tip end of the protruding portion, and the discharge hole for the fluid to be transferred is formed in a circular protruding portion. The volume of the space between the projection and the circular projection can be greatly reduced as compared with the related art. In addition, by opening the discharge hole at the end face of the distal end of the circular projection, the flow of the fluid to be transferred at the time of discharge becomes smooth, and the circulation and replacement of the fluid to be transferred at the time of discharge are improved. Can be. Therefore, the quantitative property can be improved with a simple configuration, and the quality retention of the fluid can be enhanced, so that it can be suitably used particularly for transferring a chemical solution, pure water, or the like .

[0019] Moreover, since the outer peripheral surface of the circular protrusion portion corresponding to the movable portion of the bellows is formed into a tapered surface whose diameter as the tip side along the axial direction, of the bellows during expansion and contraction of the bellows Even if the distal end side slightly oscillates, there is no operation trouble such that the distal end portion is caught on the outer peripheral surface of the protruding portion, and the pumping operation can always be maintained reliably and smoothly.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a bellows type metering pump according to one embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line AA of FIG.

FIG. 3 is a longitudinal sectional view of a main part of a conventional bellows type metering pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pump body 2 Circular projecting part 2a Tapered surface 2t Tip end face of projecting part 3 Suction hole 3a Suction hole opening 4 U-shaped grooved passage 11 Discharge hole 13 Bellows 15 Reciprocating body

Claims (1)

(57) [Claims] 1. A projection having a circular cross section, a suction hole for a fluid to be transferred is formed at a base end of the projection, and the circular shape is formed from the opening of the suction hole. A groove-like passage communicating with the suction hole is formed on a side surface of the protruding portion up to the tip of the protruding portion, and a discharge hole for the fluid to be transferred is formed on the circular protruding portion by opening to the end face of the tip. And a compression end position which is disposed on the outer periphery of the circular protrusion, one end of which is fixed to the pump body, and the other end of which closes the end surface of the distal end of the circular protrusion. And a reciprocating drive coupled to the bellows to extend and retract the bellows , the pump comprising: In the body
Of at least the movable part of the bellows
The outer peripheral surface of the corresponding part should be
A bellows type metering pump characterized by being formed on a tapered surface having a small diameter .