JP2008157164A - Piston pump for slurry - Google Patents

Abstract

A slurry pump capable of preventing slurry leakage with a simple structure without providing a packing box.
A main body casing 3 having a suction port 5 and a discharge port 6 and forming a pressurizing chamber 2, a cylinder liner 4 opening to the pressurizing chamber 2, and a cylinder liner 4 are slidably provided. A piston pump having a piston 18 that pressurizes slurry sucked from the suction port 5 by reciprocating operation and discharges the slurry from the discharge port 6, provided on the outer periphery of the piston 18 at an interval in the axial direction thereof; It has a pair of piston seals 20 and 20 forming an annular gap 21 sealed between the inner periphery of the cylinder liner and first and second chambers partitioned by a partition wall. Lubricator 22 is stored, and the second chamber communicates with the pressurizing chamber 2 to transmit the slurry pressure in the pressurizing chamber to the first chamber via the partition wall, and the first chamber and the annular gap 21. 35 which communicates with Made with a.
[Selection] Figure 1

Description

  The present invention relates to a piston pump for slurry, and more particularly to a piston pump for slurry for conveying slurry such as grout liquid and mud used for various civil engineering works such as ground improvement.

  Conventionally, as this kind of piston pump (plunger pump), a cylinder box provided with a packing box called a gland is known on the crankcase side of a cylinder liner in order to prevent slurry leakage when the piston is pressurized. In this packing box, a large number of V packings are arranged in series, and the packing row is pushed in the axial direction by pressing bushes and screws.

  However, this packing box not only has a complicated structure, but also causes an increase in the size of the entire pump. If this packing box is applied and the pump is to be miniaturized, the piston diameter must be reduced. Then, in order to maintain the required pump discharge amount, the number of reciprocating cycles of the piston must be increased, which causes early wear of the packing.

  Patent Document 1 discloses a slurry pump in which a lubricating liquid supply chamber is formed on the inner periphery of a cylinder liner, a single lip packing is provided at the front portion, and a rear portion is sealed with a gland packing. In this pump, while the pressure of the pressure feeding chamber is applied to the lubricating liquid, the pressure is further applied to supply the lubricating liquid to the lubricating liquid supply chamber at a pressure higher than that of the pressure feeding chamber. That is, a part of the lubricating liquid is allowed to flow into the pressure feeding chamber to prevent the slurry from leaking, and a gap is always formed between the one lip packing and the piston to improve the life of the lip packing.

However, the structure described in this document has a structure in which a lubricating liquid supply chamber is formed on the inner periphery of the cylinder liner and a single lip packing is attached to the cylinder liner. The inner circumference of the difficult cylinder liner must also be processed. In addition, since the lubricating liquid is always allowed to flow into the pressure feeding chamber, there is a possibility of adverse effects depending on the type of slurry. Further, a gland packing is used at the rear of the lubricating liquid supply chamber, and the structure is not yet simplified.
JP-A-1-247770 (page 439, lower right column, line 18 to page 440, upper right column, line 20, FIG. 4)

The present invention has been made based on the technical background as described above, and achieves the following object.
An object of the present invention is to provide a slurry pump that can prevent leakage of slurry with a simple structure without providing a packing box.

The present invention employs the following means in order to achieve the above object.
That is, the present invention has a main body casing that has a suction port and a discharge port and forms a pressurizing chamber therein, a cylinder liner that opens to the pressurizing chamber, and a cylinder liner that is slidably provided on the cylinder liner. A piston pump for slurry provided with a piston that pressurizes the slurry sucked from the suction port by operation and discharges the slurry from the discharge port;
A pair of piston seals that are provided on the outer periphery of the piston at an interval in the axial direction thereof and form an annular gap that is sealed with the inner periphery of the cylinder liner;
There are two chambers, a first chamber and a second chamber, which are partitioned by a partition wall. The lubricant is contained in the first chamber, and the second chamber communicates with the pressurizing chamber. A lubricator that conveys to the first chamber through the partition;
A slurry piston pump comprising a conduit communicating between the first chamber and the annular gap.

  Specifically, it is possible to adopt a structure in which the pipe line communicates with the annular gap through a hole provided in the peripheral wall of the cylinder liner. Moreover, the said pipe line can also employ | adopt the structure connected with the said annular clearance through the hole provided in the piston inside.

  According to this invention, the pressure of the pressurizing chamber and the pressure of the lubricating liquid supplied to the annular gap formed on the outer periphery of the piston are always balanced across the piston seal on the pressurizing chamber side, so that the slurry leaks out. There is nothing. Therefore, a conventional packing box is not necessary, and the pump structure is extremely simple. As a result, the inner diameter of the cylinder can be easily increased, so the number of reciprocating cycles of the piston can be reduced with the same discharge amount, and the wear and heat generation of the piston and cylinder liner can be suppressed. Can do.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of the present invention. A slurry piston pump (hereinafter simply referred to as a piston pump) 1 includes a main body casing 3 that forms a pressurizing chamber 2 therein, and a cylinder liner 4. The pressurizing chamber 2 is provided with a suction port 5 and a discharge port 6, and a suction tube 7 and a discharge tube 8 are connected to the suction port 5 and the discharge port 6, respectively.

  A suction valve chamber 9 and a discharge valve chamber 10 are provided on the pressure chamber 2 side adjacent to the suction port 5 and the discharge port 6, respectively. A ball valve 11 is disposed in the suction valve chamber 9, and this ball valve 11 is constantly urged by a coil spring 12 toward a valve seat 13 disposed on the suction port 5 side. Similarly, a ball valve 14 is disposed in the discharge valve chamber 10, and this ball valve 14 is constantly urged by a coil spring 15 toward a valve seat 16 disposed on the pressurizing chamber 2 side.

  The cylinder liner 4 is fixed to the main casing 3 by a cylinder block 17 so as to open to the pressurizing chamber 2. A piston 18 is slidably disposed in the cylinder liner 4. The piston 18 has a rear end (an end opposite to the pressurizing chamber) connected to a drive crank (not shown), and is reciprocated by its rotational drive. Slurry is sucked and discharged by the reciprocating operation of the piston 18.

  That is, as shown by the chain line position in FIG. 1, when the piston 18 moves backward, the volume of the pressurizing chamber 2 increases and becomes negative pressure, whereby the ball valve 11 in the suction valve chamber 9 opens against the coil spring 12, Slurry flows into the pressurizing chamber 2 from the suction port 5. At this time, the ball valve 14 in the discharge valve chamber 10 is closed by the urging force of the spring 15. On the other hand, as shown by the solid line position in FIG. 1, when the piston 18 moves forward, the volume of the pressurizing chamber 2 decreases to a high pressure, which causes the ball valve 14 of the discharge valve chamber 10 to open against the coil spring 15 and slurry. Is discharged from the discharge port 6. At this time, the ball valve 11 in the suction valve chamber 9 is closed by the urging force of the spring 12. In addition, the code | symbol 19 of FIG. 1 has shown the surge tank for suppressing the pulsation of a pump.

  A pair of packings 20 and 20 as piston seals are provided on the outer periphery of the piston 18 at intervals in the axial direction thereof. These packings 20 are for sealing between the outer periphery of the piston 18 and the inner periphery of the cylinder liner 4, and rubber-based ones are used. Then, as shown in an enlarged view in FIG. 4 by the pair of packings 20, 20, a sealed annular gap 21 is formed between the inner periphery of the cylinder liner 4.

  Referring to FIG. 1 again, the main body casing 3 is provided with a lubricator 22. FIG. 2 is a cross-sectional view showing the inside of the lubricator 22. The lubricator 22 is partitioned into two chambers, a first chamber 24 and a second chamber 25, by a diaphragm 23 having an internal partition, and the first chamber 24 contains a lubricating liquid. Reference numeral 29 denotes a lubricating liquid supply port. The lubricating liquid to be used can be appropriately adjusted depending on the operating pressure of the pump, the type of slurry, the degree of wear of the seal, the outside air temperature, etc., as long as it has fluidity and lubricity.

  The lubricator 22 is provided with a connector 26 that opens to the first chamber 24 and a connector 27 that opens to the second chamber 25. The main casing 3 is provided with a hole 28 that opens into the pressurizing chamber 2, and the lubricator 22 is attached to the main casing 3 by screwing a connector 27 into the hole 28. Thereby, the second chamber 25 communicates with the pressurizing chamber 2 through the hole 28. As a result, the slurry in the pressurizing chamber 2 flows into the second chamber 25, and a pressure equal to the slurry pressure acts on the lubricating liquid in the first chamber 24 via the diaphragm 23.

  As a partition arrange | positioned at the lubricator 22, not only the diaphragm 23 but a piston can also be used. FIG. 3 is a sectional view showing the embodiment. The lubricator 22 is divided into a first chamber 24 and a second chamber 25 by a piston 30. A coil spring 31 that constantly urges the piston 30 toward the second chamber 25 is disposed in the first chamber 24. Also in the lubricator 22 shown in this embodiment, the slurry flows into the second chamber 25 and gives a pressure equal to the slurry pressure to the lubricating liquid in the first chamber 24 via the piston 30.

  As shown in an enlarged view in FIG. 4, a hole 32 that opens to the annular gap 21 is provided in the peripheral wall of the cylinder liner 4. A connector 33 is attached to the hole 32, and the connector 33 and the connector 26 of the lubricator 22 are connected by a high-pressure hose 35 (see FIG. 1). In other words, the first chamber 24 in which the lubricating liquid of the lubricator 22 is accommodated and the annular gap 21 formed between the packings 20, 20 of the piston 18 communicate with each other via the high-pressure hose 35.

  Next, the operation of the above embodiment will be described. When the piston 18 moves forward and the pressure in the pressurizing chamber 2 becomes a high pressure state, the slurry flows into the second chamber 25 of the lubricator 22. Then, the pressure acts on the partition walls 23 and 30 to push out the lubricating liquid from the first chamber 24, and the lubricating liquid flows into the annular gap 21 between the packings 20 and 20 through the high-pressure hose 35. The pressure of the lubricating liquid is equal to the pressure in the pressurizing chamber 2, so that the pressure of the slurry in the pressurizing chamber 2 and the lubricating liquid flowing into the annular gap 21 is balanced across the packing 20 on the pressurizing chamber 2 side. Therefore, the slurry does not leak to the piston side.

  On the other hand, as shown in FIG. 5, when the piston 18 is retracted, the pressure in the pressurizing chamber 2 is lowered, and further enters the suction process to become a negative pressure state, the lubricating liquid flows backward to the lubricator 22 side. Also at this time, the pressure of the lubricating liquid is equal to the pressure in the pressurizing chamber 2, that is, both are always equal, and the slurry does not leak to the piston side. It is also possible to perform filtration or cooling when the lubricating liquid flows backward.

  FIG. 6 is a cross-sectional view showing another embodiment. In this embodiment, a hollow piston 40 whose rear end is open is used. In the peripheral wall of the piston 40, a hole 41 is provided that opens in the annular gap 21 between the packings 20 and 20. A connector 42 is attached to the hole 41 and a high-pressure hose 35 is connected thereto. Also according to this embodiment, the pressure of the lubricating liquid in the annular gap 21 is always equal to the pressure in the pressurizing chamber 2, and the slurry can be prevented from leaking to the piston side.

  As described above, according to the present invention, the pressure in the pressurizing chamber 2 and the pressure of the lubricant supplied to the annular gap 21 formed on the outer periphery of the piston are always between the piston seal 20 on the pressurizing chamber side. Since the balance is achieved, the slurry does not leak out. Therefore, a conventional packing box is not required, and the pump structure is extremely simple. As a result, the inner diameter of the cylinder can be easily increased, so the number of reciprocating cycles of the piston can be reduced with the same discharge amount, and the wear and heat generation of the piston and cylinder liner can be suppressed. Can do.

  Further, unlike a general plunger pump, by incorporating a rubber packing as a piston seal, it is possible to feed a grouting liquid (mortar) containing sand as a slurry.

  In addition, since the structure is simple, maintenance is easy. Further, as shown in the figure, by providing a valve chamber for suction and discharge so as to be substantially symmetric with respect to the cylinder axis, it can be used upside down. As a result, the discharge side generally wears early, but the life of the pump body can be extended by reversing the time and changing the suction side and the discharge side.

It is sectional drawing which shows embodiment of this invention. It is sectional drawing which shows a lubricator. It is sectional drawing which shows another example of a lubricator. It is a figure for demonstrating the effect | action at the time of piston advance. It is a figure for demonstrating the effect | action at the time of piston backward movement. It is sectional drawing which shows another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Piston pump 2 Pressurization chamber 3 Main body casing 4 Cylinder liner 5 Suction port 6 Discharge port 9 Suction valve chamber 10 Discharge valve chamber 11 Ball valve 14 Ball valve 18 Piston 20 Packing 21 Annular clearance 22 Lubricator 23 Diaphragm 24 First chamber 25 First 2 chambers 28 holes 30 piston 32 holes 35 high pressure hose 40 piston 41 holes

Claims (3)

A main body casing having a suction port and a discharge port and forming a pressurizing chamber therein, a cylinder liner opening to the pressurizing chamber, and a slidably provided in the cylinder liner, and reciprocatingly operating the suction A piston pump for slurry comprising a piston that pressurizes the slurry sucked from the port and discharges the slurry from the discharge port,
A pair of piston seals that are provided on the outer periphery of the piston at an interval in the axial direction thereof to form a sealed annular gap with the inner periphery of the cylinder liner;
There are two chambers, a first chamber and a second chamber, which are partitioned by a partition wall. The lubricant is contained in the first chamber, and the second chamber communicates with the pressurizing chamber. A lubricator that conveys to the first chamber through the partition;
A slurry piston pump comprising: a conduit communicating between the first chamber and the annular gap.   The slurry piston pump according to claim 1, wherein the pipe line communicates with the annular gap through a hole provided in the peripheral wall of the cylinder liner.   The slurry piston pump according to claim 1, wherein the pipe line communicates with the annular gap through a hole provided in the piston.

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