JPH0133672B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reciprocating pump device, and more specifically, the present invention relates to a reciprocating pump device, and more specifically, the device of the present invention for pumping a highly abrasive and highly viscous material includes an air piston that slides within an air cylinder body. The piston that reciprocates in the pump chamber is integrally connected with a rod, and a gap exists between the inner wall of the pump chamber and the outer peripheral surface of the piston, and a space with an inner diameter smaller than the outer diameter of the piston is formed on the inner wall of the housing. A ring-shaped flexible elastic seal is attached to the outer circumferential surface of the piston so that it can come into contact with it, and a bellows is fitted over almost the entire surface of the piston rod to cover it, and one end of the bellows is placed at a predetermined distance from the surface of the rod and It is fixed to the cylinder body, and the other end of the bellows is fixed to the surface of the rod.
It is characterized by the provision of a surge tank to protect the bellows opening into the pump chamber.

Conventional piston pumps have a structure in which the packing is constantly rubbing against the inside of the cylinder or the rod surface, and there is also a small gap between the piston and the cylinder, so the packing is often worn especially when using materials containing silica sand, etc.
The drawback was that the gaskets had to be replaced frequently. In addition, as the piston rod reciprocates inside and outside the cylinder, the material attached to the rod comes into contact with the outside air, which can cause malfunctions, especially with quick-drying materials, and it is necessary to take measures to prevent sticking.

An object of the present invention is to solve the above-mentioned problems and provide a pump device suitable for pumping materials including aggregate.

An embodiment of the present invention will be described below with reference to the drawings. 1a is the pump device on the right side.
Compressed air passages 13 and 14 are opened in the air cylinder main body 2 which has a cylindrical shape with a bottom. In addition, the air cylinder body 2 has an air piston 15 (described later).
Pins 28 and 29 are provided to detect the extreme position of. A cylindrical intermediate housing 3a is fixed to one end of the air cylinder main body 2, and forms a pump chamber 23a inside. A surge tank 21a that opens into a material suction pipe 11a and a pump chamber 23a is attached to the intermediate housing 3a.

A seal pressing plate 1 is attached to the end of the intermediate housing 3a.
An end housing 20a is attached to sandwich the end housing 8a. A pump chamber 24a is formed inside the end housing 20a. FIG. 2 shows an enlarged view of part A, in which the seal presser plate 18a cooperates with the end housing 20a to form a ring-shaped flexible elastic seal 1 having a cavity with an inner diameter smaller than the outer diameter of the piston.
Supports 9a. The tip of the seal 19a forms a lip 31a.

A check valve 25a is attached to the end of the end housing 20a. End housing 20a and check valve 25
A valve seat 32a is provided at the boundary of the ball 26a, and when there is no pressure, the ball 26a is seated on the valve seat 32a due to the elastic force of the spring 27a. The figure shows the valve in the open state where material is being pumped. The check valve 25a is connected to the discharge pipe 12
It is connected to a.

An air piston 15 is slidably provided inside the air cylinder body 2. Piston 1 is attached to the tip of rod 4a extending from air piston 15.
6a is attached, and the piston 16a can reciprocate within the pump chambers 23a and 24a. It is necessary to provide a gap between the inner walls of the pump chambers 23a and 24a and the outer peripheral surface of the piston 16a. In the pump chamber 23a, a telescopic bellows 22a is fitted to the rod 4a,
One end of the bellows 22a is fixed to the air cylinder body 2 at a position 33a that is a predetermined distance h from the surface of the rod 4a, and the other end of the bellows 22a is fixed to the air cylinder body 2 at a position 34a on the rod 4a.
is fixed to. The bellows 22a and 22b are filled with air, and extreme deformation of the bellows is prevented by communicating the inside of the bellows with the atmosphere (for example, by drilling a communication path in the wall of the air cylinder body 2). . On the opposite side of the air piston 15, a rod 4b and a piston 16b are provided symmetrically to the rod 4a and the piston 16a.
A bellows 22b is fitted into the rod 4b.

A pump device 1b is provided symmetrically to the pump device 1a with the air cylinder main body 2 as the center of symmetry. That is, with the air cylinder body 2 as the center of symmetry, the intermediate housing 3b, the end housing 20b, and the check valve 25b are located on the left side of the air cylinder body 2, symmetrically with the intermediate housing 3a, the end housing 20a, and the check valve 25a. It is provided. A pump chamber 23b is formed in the intermediate housing 3b, and the material suction pipe 11b and the pump chamber 23
An open surge tank 21b is attached to b. Pump chambers 23b and 24b are formed in the intermediate housing 3b and the end housing 20b, respectively, and a seal 19b is supported by a seal holding plate 18b. The check valve 25b is connected to the discharge pipe 12b.
communicate with. 32b is the valve seat. 26b is the ball, 2
7b is a spring.

10 is a material can containing a high viscosity material M, for example, a material containing aggregate such as silica sand.

FIG. 4 is a flow sheet of the switching mechanism. 6,
7 and 8 are switching valves, and 9 is a pressure reducing valve. 25a is a check valve of the pump device 1a on the right side, 25b is a check valve of the pump device 1b on the left side, and 10 is a material can.

The operation of the apparatus of the present invention having the configuration described above will be explained. Since the pump device 1a on the right side and the pump device 1b on the left side each perform the suction stroke and the discharge stroke in reverse, the mechanism for sucking and discharging the material will be explained with respect to the pump device 1a on the right side.
When the pump starts operating, it first discharges the air in the pump chamber and the suction pipe 11a and then discharges the material, but since the operating principle is the same, here the pump chamber and the suction pipe 11a are filled with material. Let me explain from the situation.

By the switching valve 6, compressed air enters the cylinder from the passage 13 provided in the air cylinder body 2, and the air piston 15 and piston 16a
Push to the right. The volume of the pump chamber 24a formed within the end housing 20a is reduced and the material therein is pressurized. As shown in FIG. 2, the pressurized material pushes face 30a of piston 16a and lip 31a of seal 19a in the direction of arrow C. Here, the lip 31a is the seal pressing plate 18a.
This prevents the lip 31a from bending in the opposite direction, and the pressure causes the lip 31a to be pressed against the circumferential surface of the piston 16a.
Improves sealing performance. The pressurized material passes through check valve 2
It pushes the ball 26a of 5a and is discharged from the discharge pipe 12a.

When the air piston 15 reaches the right extreme position,
When the pin 28 of the switching valve 8 is pushed, the switching valve 6 is operated, compressed air is sent into the cylinder from the passage 14, and the air piston 15 and piston 16a are pushed to the left. The rod 4a moves the air cylinder body 2 as the air piston 15 moves.
However, since it is sealed by the bellows 22a, it does not touch the material, thus preventing it from entering the air cylinder body 2. As the piston 16a moves to the left, the volume of the pump chamber 24a increases, creating negative pressure inside.
Ball 26a of check valve 25a is pressed against valve seat 32a. When the piston 16a is further pushed to the left, the negative pressure increases, and as shown in FIG.
The material in 3a is attached to the seal 19 as shown by arrow d.
A phenomenon occurs in which the pump enters the pump chamber 24a from between the lip 31a of the piston 16a and the piston 16a.
Note that as the piston 16a moves, the volume of the pump chamber 23a actually becomes smaller, and the suction pipe 1
1a, but the volume of the pump chamber 23b of the left pump device 1b increases by the same volume, so that the material only moves through the suction pipes 11a, 11b.

The effects of the present invention are as follows.

In the present invention, a bellows is fitted and covered over the rod of a piston, one end of the bellows is fixed to the air cylinder body at a predetermined distance h from the surface of the rod, and the other end of the bellows is fixed to the outer peripheral surface of the rod. Therefore, there is no risk of material adhering to the part where the rod slides on the air cylinder body, and this completely prevents material from entering the air cylinder, preventing long-term damage to the equipment. It can be used without.

In FIG. 3, considering the stroke in which the piston 16a moves to the left, the lip 31a of the seal 19a
immediately before it leaves the piston 16a, the pump chamber 24
The negative pressure at a reaches its maximum, and the moment the piston 16a separates from the lip 31a, the pressure inside the pump chamber 23a drops suddenly and a pressure wave is generated. At this time, assuming that the surge tank 21a is not provided, water hammer occurs due to the generation of this pressure wave, and severe pressure changes are repeated in the pump chamber 23a. The bellows 22a repeatedly expands and collapses due to the pressure change, which may lead to damage. Since the present invention provides a surge tank in the pump chamber, it is possible to soften the impact, protect the bellows, and improve durability. To explain more specifically what it means to soften the impact, firstly, the gas trapped in the upper part of the surge tank (usually air, but it is also possible to use a gas other than air). is maintained at atmospheric pressure and has the effect of releasing pressure waves. Second, when the pressure within the pump chamber changes, material within the surge tank moves in and out of the pump chamber, mitigating pressure changes within the pump chamber.
That is, when the pressure in the pump chamber drops, material is replenished into the pump chamber to reduce the pressure drop.

[Brief explanation of drawings]

Fig. 1 is a sectional view of one embodiment of the device of the present invention;
3 and 3 are enlarged views of section A in FIG. 1, and FIG. 4 is a flow sheet of the switching mechanism. 1a...Pump device on the right side, 1b...Pump device on the left side, 2...Air cylinder body, 3a, 3
b...middle housing, 4a, 4b...rod,
6, 7, 8...Switching valve, 9...Pressure reducing valve, 15...
Air piston, 16a, 16b...piston,
19a, 19b... Seal, 20a, 20b...
End housing, 21a, 21b... surge tank, 22a, 22b... bellows, 25a, 25
b...Check valve.

Claims (1)

[Claims] 1. An air piston that slides within the air cylinder body and a piston that reciprocates within the pump chamber are integrally connected with a rod, and a space is created between the inner wall of the pump chamber and the outer peripheral surface of the piston, and the housing A ring-shaped flexible elastic seal having a hole with an inner diameter smaller than the outer diameter of the piston is attached to the inner wall so that it can come into contact with the outer peripheral surface of the piston, and a bellows is fitted over almost the entire surface of the piston rod to cover it, and one end of the bellows is The bellows is fixed to the air cylinder body at a predetermined distance from the surface of the rod, the other end of the bellows is fixed to the surface of the rod, and a surge tank is provided to protect the bellows opening into the pump chamber. A device that pumps highly abrasive and highly viscous materials.