JPH01247770A - Slurry pump - Google Patents

Abstract

PURPOSE:To prevent a packing or the like from being damaged by slurry by a method wherein around a main body of a plunger inside a pump main body, a lubricant supply chamber whose pressure is higher than that of a gas compressor chamber which is communicated with the gas compressor chamber of slurry via a fine slit is provided. CONSTITUTION:A whole body of a slurry pump 30 consists of a main pump body 32, a plunger assembly 34 and a lubricant supplying part 36. Reciprocating motion of a plunger main body 84 in a cylinder 38 in the plunger assembly 34 causes slurry to be sucked into a gas compressor chamber 88 from an inlet passage 56 and then to be exhausted to an exhaust passage 58. In this constitution, a portion having a small diameter 84B is sealed by a lip packing 48. A lubricant supply chamber 86 is formed between a plurality of flanges 40, 42 in the cylinder 38. During reciprocating process of the plunger main body 84, inner pressure of the lubricant supply chamber 86 is kept higher than the inner pressure of the gas compressor chamber 88.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a slurry pump that pumps slurry such as cement milk or muddy water under high pressure. Regarding the configured slurry pump.

[Conventional technology]

As shown in FIG. 6, in a slurry pump 10 conventionally used for grouting work, ground improvement work, polling work, etc., a plunger 14 is slidably supported within a cylindrical pump body 12. is reciprocated by a driving means 16. Further, the pump body 12 is provided with a suction valve 18 for sucking slurry into the pump body 12 and a discharge valve 20 for discharging the slurry from within the pump body.

In the pump 10 configured in this way, when the plunger 14 moves to the right, the volume of the pumping chamber 22 decreases and its internal pressure increases, so that the ball valve 2 of the discharge valve 20
OA moves upward against the biasing force of spring 20B and opens hole 20C. Therefore, the slurry in the pumping chamber 22 is discharged.

Next, when the plunger 14 moves to the left, the pressure feeding chamber 2
Since the volume of the hole 2 increases and becomes negative pressure, the ball valve 20Δ of the discharge valve 20 is urged by the spring 20B and the hole 2
Close 0C. At the same time, the ball valve 18 of the suction valve 18
A moves upward against the biasing force of the spring 18B and opens the hole 18C, so that the slurry is sucked into the pressure feeding chamber 22. In this way, the slurry is sucked and discharged by reciprocating the plunger 1.4.

The packing 24 also prevents the slurry from leaking between the plunger 14 and the pump body 12.
It is arranged on the inner periphery of 2.

[Problems to be Solved by the Invention] However, in this type of slurry pump, when the pressure inside the pumping chamber 22 is used at a high pressure of, for example, several 100 kg/cd, the plunger 14 slides while being tightly bound by the packing 24. Therefore, there was a drawback that the life of the gasket 24 was short due to the synergistic effect of frictional resistance and frictional heat. Furthermore, since the slurry enters between the packing 24 and the plunger 14, the plunger 14 as well as the packing 24 is damaged, resulting in a short lifespan of the packing.

The present invention has been made in view of the above circumstances, and by supplying an optimum amount of lubricating fluid from the lubricating fluid supply chamber to the pumping chamber in response to changes in the internal pressure of the pumping chamber caused by the reciprocating movement of the plunger, The purpose of the present invention is to provide a slurry pump that can prevent damage to the packing, plunger, etc.

[Means for solving problems]

In order to achieve the above object, the present invention reciprocates shaft bodies such as plungers and pistons in the axial direction within the pump body to alternately change the pressure in the pumping chamber, thereby sucking slurry into the pumping chamber and discharging it. In slurry pumps that
It is characterized in that a lubricant supply chamber is formed around the shaft and communicates with the pumping chamber through a small gap, and the pressure in the lubricant supply chamber is changed in response to changes in the pressure in the pumping chamber.

[Effect]

According to the present invention, the internal pressure of the lubricant supply chamber changes in response to changes in the internal pressure of the pumping chamber, and is slightly higher than the internal pressure of the pumping chamber, so that the fluid in the lubricant supply chamber is gradually supplied into the pumping chamber. be done.

〔Example〕

Preferred embodiments of the slurry pump according to the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 1, a slurry pump 30 according to the present invention
is composed of a pump body 32, a plunger portion 34, and a lubricant supply portion 36.

The pump body 32 has a cylindrical body 38 with one end closed, and the cylindrical body 38 has a first flange 40, a second flange 42, and a third flange 44 formed on its inner peripheral surface. Further, a packing 46 is provided on the left side of the first flange 40 in FIG. 1, and a lip packing 48 is provided between the second flange 42 and the third flange 44.

Further, a suction passage 56 is provided below near the closed portion of the cylinder 38, and a discharge passage 58 is provided above. The suction passage 56 has a valve chamber 60 in which a ball valve 62 is disposed, and the ball valve 62 is connected to the suction hole 6 by a spring 64.
It is biased in the direction of closing 0B. In addition, the discharge passage 5
8 has a valve chamber 66, in which a ball valve 68 is arranged, and the ball 68 is urged by a spring 70 in a direction to close the discharge hole 66B. A guide member 72 is secured to the other end of the cylindrical body 38 by tightening the gasket 46 with a bolt 74. Further, the cylinder body 38 has a check valve 76 approximately in the center thereof.
The ball valve 78 of the check valve 76 has a spring 8
0 and closes the hole 82.

The plunger portion 34 has a plunger body 84 that can slide within the cylindrical body 38, and the plunger body 84 forms a large diameter portion 84A and a small diameter portion 84B. Large diameter portion 84
A is sealed with packing 46 and has a small diameter! 84B is sealed with a lip seal 48. A lubricant supply chamber 86 is provided between the first flange 40 and the second flange 42 of the cylinder 38.
Further, a pressure feeding chamber 88 is formed at the right end of the cylindrical body 38. The left end of the plunger body 84 in FIG. 1 is connected to a rod 90, and the rod 90 is connected to a drive crank 92. Therefore, the plunger body 84 is rotated through the rod 90 by the rotation of the drive crank 92 to connect the cylinder body 38 to the cylindrical body 38.
You can move back and forth within.

The lubricating fluid supply section 36 has a lubricating fluid supply tank 94 , one end of which is connected to the tank 94 and the supply pipe 96 .
The other end is communicated with a check valve 76 of the cylindrical body 38 . The tank 94 is located at a predetermined height (H) from the axis of the plunger body 84.
-) are maintained. Furthermore, a lubricant supply pump 95 may be added in addition to the tank. Or pump 95
It is also possible to obtain a pressurizing means by using only the above. As the lubricating liquid, a liquid such as fresh water that does not contain solid powder and can be used even when mixed with the fluid to be pumped is used.

The operation of the slurry pump according to the present invention configured as described above will be explained.

First, when the plunger body 84 moves to the left in FIG.
The ball valve 68 closes the discharge hole 66B, but the ball valve 62 of the suction passage 56 opens the suction hole 60B against the urging force of the spring 64. Therefore, the slurry is sucked into the pumping chamber 88 through the suction passage 58 . On the other hand, at this time, the large diameter portion 84A of the plunger body 84 retreats from inside the lubricant supply chamber 86, so the lubricant supply chamber 86
4A and the diameter and cross-sectional area of the small diameter portion 84B, negative pressure is generated, and the fluid passes through the check valve 76 and flows into the tank 94.
Since the lubricating liquid flows into the lubricating liquid supply chamber 86 from the lubricating liquid supply chamber 86, the internal pressure of the lubricating liquid supply chamber 86 becomes higher than the internal pressure of the pumping chamber 88 by a head pressure H. By the way, as shown in FIG.
In general, when the internal pressure of the pressure-feeding chamber 88 increases, pressure acts on the pressure-receiving surface and seals the plunger body 84, but when the internal pressure of the lubricant supply chamber 86 increases, the pressure that acts on the back surface increases and seals the plunger body 84. It is formed to release the . Therefore, as shown in FIG. 3(A), the liquid in the lubricant supply chamber 86 flows out slightly into the pressure feeding chamber 88, and the slurry does not come into contact with the sliding surface of the lip packing 48.

Next, when the plunger body 84 moves to the right in FIG.
2 downward until it closes the suction hole 60B.

At the same time, the ball valve 68 moves upward against the urging force of the spring 70 and opens the discharge hole 66B, so that the slurry is discharged. On the other hand, since the large diameter portion 84A of the plunger body 840 enters the lubricant supply chamber 86, the volume decreases by the difference in cross-sectional area between the diameter of the large diameter portion 84A and the diameter of the small diameter portion 84B of the lubricant supply chamber 86, and the internal pressure As shown in FIG. 3(B), the liquid in the lubricating fluid supply chamber 86 flows out slightly into the pressure feeding chamber 88, and the slurry comes into contact with the sliding surface of the lip packing 48. do not. in this case,
The seal 46 always seals the plunger body 84.

In this manner, during the suction and discharge strokes of the plunger body 84, the internal pressure of the lubricating fluid supply chamber 86 is maintained slightly higher than the internal pressure of the pumping chamber 88, so that the lubricating fluid slightly flows into the pumping chamber 88. Therefore, the lip packing 48 does not come into direct contact with the slurry and is constantly cleaned by the lubricating fluid, so that the slurry can be transported under high pressure without being damaged.

In the above-mentioned pressurizing means, the shaft body sliding in the lubricating fluid supply chamber had a large diameter part and a small diameter part to force the lubricating fluid, but the shaft body was not provided with a large diameter part and a small diameter part, but had the same diameter, Alternatively, a lubricant supply pump that generates a pressure slightly higher than the pressure in the pressure chamber and has an appropriate discharge flow rate may be used. That is, this can be done by detecting the pressure in the pressure feeding chamber electrically or by other means, and changing the supply pressure of the lubricant supply pump in response to changes in the pressure in the pressure feeding chamber. Alternatively, the lubricating fluid may be injected from a minute gap by a pump having an appropriate discharge amount and generating a pressure slightly higher than the pressure in the pressure feeding chamber in advance without responding to changes in the pressure in the pressure feeding chamber.

Further, the present invention is not limited to this, and a configuration as shown in FIG. 4 may be used. The second embodiment shown in FIG. 4 will be described below.

Note that descriptions of the same members as in the previous embodiment will be omitted.

A cylinder 106 is formed in the cylindrical body 102 of the slurry pump 100 and is open to the pressure feeding chamber 104.
A piston 108 is slidably supported at 6. Further, a spring 110 is attached to the cylinder 106 to bias the piston 108 toward the pressure-feeding chamber 104 .

Further, the cylinder 106 communicates with the lubricant supply tank 112 via a supply pipe 114 and a check valve 126, and communicates with the check valve 76 via a supply pipe 116. Also, cylinder 1
06 and the piston 108 are sealed with a seal 118.

The operation of the slurry pump 100 configured in this way will be explained.

First, when the plunger 120 enters the pressure-feeding chamber 104, the pressure within the pressure-feeding chamber 104 increases, and the piston 108 moves rightward in FIG. 4 against the biasing force of the spring 110. As a result, the volume of the adjustment chamber 122 decreases and the pressure increases, so the lubricant therein is transferred to the supply pipe 116 and the check valve 7.
6 into the lubricant supply chamber 124. Therefore,
The internal pressure of the lubricant supply chamber 124 increases, and the lubricant supply chamber 1
24 flows out slightly into the pumping chamber 104, and the slurry does not come into contact with the sliding surface of the lip packing 48.

From this state, when the plunger 120 is moved in a direction to retreat from the pressure-feeding chamber 104, the pressure inside the pressure-feeding chamber 104 becomes negative, and the piston 108 is urged by the spring 110 and moves in the direction inside the pressure-feeding chamber 104. At this time, the adjustment room 122
The lubricating liquid is supplied from the lubricating liquid supply tank 112 through the check valve 26 and the supply pipe 114 and has a predetermined height H, so that the lubricating liquid is slightly supplied to the pumping chamber 1 from the lubricating liquid supply chamber 124.
04, and the lip packing can create a state in which it does not come into contact with the slurry.

In this way, in the second embodiment as well, the internal pressure of the lubricating fluid supply chamber 124 is maintained higher than the internal pressure of the pumping chamber 104 during the suction and discharge strokes of the plunger 120, so that the lubricating fluid slightly flows out into the pumping chamber 104. There is. Therefore, the slurry does not come into contact with the sliding surface of the lip packing 48.

Further, although the lip seal was used in the above embodiment, the present invention is not limited to this, and as shown in FIG. 5, a slight gap e may be formed between the plunger and the cylindrical body without using the lip seal. You can.

In other words, since a higher pressure is applied to the lubricating liquid supply chamber than that of the pressure feeding chamber, the lubricating liquid will not flow into the feeding chamber through the minute gap and the slurry will not enter the lubricating liquid supply chamber, so there may be cases where a lip seal is not used. It is possible. The lip gasket is provided as a safety measure to prevent slurry from entering the lubricant supply chamber in the event that a problem occurs in the pressure management between the lubricant supply chamber and the pressure-feeding chamber.

In the embodiment described above, a lubricating liquid supply tank is used, but the present invention is not limited to this, and a liquid pump capable of generating a pressure slightly higher than the pressure in the pumping chamber may be used.

〔Effect of the invention〕

As explained above, according to the slurry pump of the present invention, the internal pressure of the lubricating liquid supply chamber is slightly higher than the internal pressure of the pumping chamber, so the liquid in the lubricating liquid supply chamber is gradually supplied into the pumping chamber through the small gap. be done.

Therefore, the slurry in the pressure feeding chamber does not enter the lubricating fluid supply chamber through the minute gap, so it becomes possible to transport ultra-high pressure slurry without damaging the plunger or piston packing.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of an embodiment of the slurry pump according to the present invention, Figure 2 is a cross-sectional view of a knob seal used in the embodiment of the slurry pump according to the present invention, and Figures 3 (A) and (B) are 4 is a cross-sectional view of a second embodiment of the slurry pump according to the present invention, and FIG. 5 is a lip used in the slurry pump according to the present invention. FIG. 6 is a sectional view showing a conventional slurry pump without a packing. 30...Slurry pump, 32...Pump,
34...Plunger part, 36...Fluid supply part,
48... Lip packing, 88... Pressure feeding chamber.

Claims (3)

[Claims] (1) In a slurry pump that sucks slurry into the pumping chamber and discharges it by reciprocating the shaft bodies such as plungers and pistons in the axial direction within the pump body to alternately change the pressure in the pumping chamber, the shaft A slurry pump characterized in that a lubricating liquid supply chamber is formed around the body and communicates with a pumping chamber through a small gap, and the pressure of the lubricating liquid supply chamber is changed in response to pressure changes in the pumping chamber. (2) The pressure in the lubricant supply chamber is changed by alternately advancing and retreating a large diameter portion and a small diameter portion formed on the shaft body into the lubricant supply chamber, and the lubricant is forced into the chamber through the minute gap. The slurry pump according to claim 1, further comprising pressurizing means for causing the slurry to flow out. (3) The slurry pump according to claim 1, wherein the minute gap is provided with a lip packing that allows the lubricant to flow out from the lubricant supply chamber to the pumping chamber.