JP3859750B2 - High pressure pump sealing method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a sealing method and apparatus for a high-pressure pump that pressurizes a fluid to a high pressure, and in particular, a sealing method for a high-pressure pump that can be continuously operated without stopping pressurization of a fluid in which a solid is suspended. And apparatus.
[0002]
[Prior art]
Various pumps are used to pressurize the fluid to a high pressure. Known high-pressure pumps include plunger-type and diaphragm-type pumps, and their driving methods include those in which the plunger is directly driven by a motor and those in which it is indirectly driven by hydraulic pressure or the like.
Various types of these high-pressure pumps are used according to the type of fluid used and the operating pressure. High-pressure water generation pumps used for water jet processing of metals and high-hardness materials use high pressures of 1500 atm or higher, and these pumps generally wear important parts in about 500 to 2000 hours. It has become necessary to stop the operation and replace parts.
[0003]
Therefore, the present inventor has a high pressure cylinder in which a vertically moving plunger is inserted from above as a high pressure pump for pressurizing a solid-liquid mixed phase fluid, and at least the fluid flows into or out of the bottom of the high pressure cylinder. It has one opening, and has a hydraulic cylinder for driving the plunger above the high-pressure cylinder. Between the hydraulic cylinder and the high-pressure cylinder, the hydraulic oil leaking from the hydraulic cylinder in contact with the plunger drive shaft A high-pressure pump with a means for preventing transition to the plunger surface that fits into the high-pressure cylinder was proposed.
However, a high-pressure pump that handles such a solid-liquid mixed phase fluid has been required to operate stably for a longer period of time.
[0004]
In JP-A-4-181072, in a high-pressure slurry pump that sucks and discharges slurry by reciprocating movement of the plunger, the plunger sliding portion is sealed with a plurality of packings between the slurry chamber and the outside, A sealing method for a high-pressure slurry pump is described in which a sealing liquid is supplied to a middle portion in the row direction of a plurality of packings at a pressure equal to or higher than the pressure on the slurry chamber side. In this method, a very small amount of the sealing liquid is always mixed into the slurry through the gap of the V packing, and strict management of the slurry concentration is impossible. In addition, in the attachment method of the V-packing in the attached drawing, the negative pressure is generated inside the cylinder at the time of suction, and at this time, a large amount of the sealing liquid flows into the cylinder from the gap of the V-packing in order to prevent this. However, since it is necessary to use a pump that pushes the slurry into the cylinder at a pressure higher than the sealing liquid pressure, such a method seems to be impossible in practice.
[0005]
[Problems to be solved by the invention]
It is an object of the present invention to provide a seal for a high-pressure pump having excellent durability, and in particular, it is possible to pressurize a fluid that wears component parts of a device such as a solid-liquid mixed phase fluid to a high pressure. Another object of the present invention is to provide a highly durable seal for a high pressure pump.
[0006]
[Means for Solving the Problems]
The present invention relates to a sealing method for a sliding part of a high-pressure pump for pressurizing a fluid in which a solid is suspended, and when the pump is pressurized, a fluid having a pressure higher than the pressure applied by the pump is introduced to By deforming the pressure fluid introducing ring arranged at the sliding portion of the cylinder and the O ring arranged on both sides of the pressure fluid introducing ring, the main seal arranged outside the O ring is deformed, and the plunger and the cylinder This is a high pressure pump sealing method in which a space in which a solid is suspended is prevented from entering the seal portion by forming a space having a pressure higher than the pressure applied by the pump.
Further, in a sealing device for a sliding part of a high-pressure pump for pressurizing a fluid in which a solid is suspended, a plunger and a cylinder are provided with a pressure fluid introduction ring for introducing a fluid having a pressure higher than the pressure of the pump when the pump is pressurized. O-rings are arranged on both sides of the pressure fluid introduction ring, and a main seal is arranged on the outside of the O-ring, which is deformed by the action of pressure fluid and seals the sliding surface. In addition, the high pressure pump sealing device has a space higher in pressure than the pressure applied by the pump.
[0007]
【Example】
The present invention will be described in more detail with reference to the drawings.
FIG. 1 is a view for explaining one embodiment of a high pressure pump to which a seal of a high pressure pump according to the present invention is applied. The high-pressure pump 1 has a high-pressure cylinder 3 into which a plunger 2 is fitted from the top, and supplies hydraulic oil 5 to a hydraulic cylinder 4 provided at the top to reciprocate the plunger up and down. The hydraulic oil is pressurized by a pressurizing mechanism including a hydraulic pump 7 driven by a motor 6, is switched by a four-way switching valve 8, is supplied to a hydraulic cylinder, and reciprocates left and right hydraulic cylinders alternately. The plunger reciprocates inside the cylinder, and the fluid is pressurized to a high pressure by the action of the check valves 9 and 10.
[0008]
FIG. 2 is a diagram for explaining a sealing device for a high-pressure pump according to the present invention. The right side of the figure shows the state of the unpressurized seal, and the left side is a cross-sectional view illustrating the sealing device when pressurized.
The sliding portion between the plunger 2 and the high-pressure cylinder 3 includes main seals 11a and 11b, backup rings 12a, 12b, 13a, 13b, 14a and 14b, O-rings 15a and 15b, and a pressure fluid introduction ring 16. Yes. From the pressure fluid supply port 17 of the high-pressure pump, the pressure fluid is adjusted to a pressure 5 to 10% larger than the pressurization pressure of the high-pressure pump and is allowed to flow. The inflowing pressure fluid is filled in the groove 18 provided around the pressure fluid introduction ring 16, and the O-rings 15a and 15b are deformed by the pressure fluid as shown on the left side. The main seals 11a and 11b are deformed by the action, and a high pressure space 19 higher in pressure than the pressure applied by the pump is formed in the space surrounded by the main seals 11a and 11b.
As a result, when the plunger is lowered, the suspension fluid 20 rises up to the main seal, but a high pressure space slightly higher than the pressurizing force of the pump is formed inside the main seal. Turbid fluid does not enter.
[0009]
In the sealing device of the present invention, the material used for the sealing device can be appropriately selected according to the fluid or pressure used. For example, for the main seal, ultrahigh molecular weight polyethylene can be used, and the backup ring 12a, 12b is stainless steel such as SUS316, the backup rings 13a and 13b are carbon fiber reinforced fluororesin, polyether ether ketone, the backup rings 14a and 14b are fluororesin, and the O-rings 15a and 15b are fluorine. Resin-based elastomers can be used. Further, it is preferable to use a metal material such as SUS316 for the pressure fluid introduction ring.
[0010]
【The invention's effect】
In the present invention, a high pressure space is formed in the seal portion by a pressurized fluid introduced from the outside into the seal portion when the high pressure pump is pressurized, and a main seal that is deformed by the pressurized fluid and is in close contact with the sliding portion is provided. Therefore, the fluid in which the solid particles are suspended does not enter the main seal portion, and a high-pressure pump having a long-life seal is obtained even when the fluid in which the solid is suspended is pressurized to a high pressure. Can do.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a high-pressure pump to which a seal of the present invention is applied.
FIG. 2 is a diagram illustrating a seal of a high-pressure pump according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... High pressure pump, 2 ... Plunger, 3 ... High pressure cylinder, 4 ... Hydraulic cylinder, 5 ... Hydraulic oil, 6 ... Motor, 7 ... Hydraulic pump, 8 ... Four-way selector valve, 9 ... Pipe line, 11a, 11b ... Main seal , 12a, 12b, 13a, 13b, 14a, 14b ... backup ring, 15a, 15b ... O-ring, 16 ... pressure fluid introduction ring, 17 ... pressure fluid supply port, 18 ... groove, 19 ... high pressure space

Claims (2)

  In the sealing method of the sliding part of the high-pressure pump for pressurizing the fluid in which the solid is suspended, when the pump is pressurized, a fluid having a pressure higher than the pressure of the pump is introduced to slide the plunger and the cylinder. The main seal disposed on the outside of the O-ring is deformed by deforming the pressure fluid introduction ring disposed on the O-ring and the O-ring disposed on both sides of the pressure fluid introduction ring, thereby sealing between the plunger and the cylinder. In addition, a high pressure pump sealing method is characterized in that a liquid having a solid suspended therein is prevented from entering the seal portion by forming a space whose pressure is higher than the pressure applied by the pump.   In a sealing device for a sliding part of a high-pressure pump for pressurizing a fluid in which a solid is suspended, a pressure fluid introduction ring for introducing a fluid having a pressure higher than the applied pressure of the pump is provided between the plunger and the cylinder when the pump is pressurized. O-rings are arranged on both sides of the pressure fluid introduction ring, and a main seal is arranged outside the O-ring, and is deformed by the action of pressure fluid to seal the slide surface. A high pressure pump sealing device characterized in that a space having a pressure higher than the pressure of the pump is formed.

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