JP3561567B2 - Sealing device for plunger type compressor - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a sealing device for a sliding portion of a plunger compressor. More specifically, the present invention relates to a sealing device for a plunger compressor using a packing having a rectangular cross section for a sliding portion, and particularly to a sealing device using a combination of two types of packing.
[0002]
[Prior art]
A plunger pump, that is, a plunger-type compressor, is a reciprocating pump that reciprocates a round bar-shaped plunger in a cylinder to suck and discharge fluid by changing the volume in the cylinder. Usually, a plunger compressor is used for high pressure. Therefore, high pressure airtightness is required between the plunger and the cylinder.
[0003]
In such a plunger type compressor, packing is interposed in a sliding portion between the cylinder and the plunger. The packing that prevents the fluid to be compressed from leaking from the sliding portion maintains the compressibility of the compressor. As packing for preventing the fluid to be compressed from leaking from the sliding portion, packing having a V-shaped cross section, that is, V-packing is commonly used to ensure airtightness under high pressure.
[0004]
The V-packing is pressed in the axial direction by the gland, and is retightened in the axial direction according to the degree of wear. If the reciprocating cycle of the plunger is shortened in order to increase the discharge capacity, the life of the V-packing is sharply shortened. A gland packing having a rectangular cross section is used instead of the V packing for the pump having a large discharge amount.
[0005]
Even with a pump using such a rectangular packing, when the compression ratio is reduced to some extent, fine particles enter and the pain of the sealing surface of the packing rapidly progresses, and the plunger wears out, rapidly losing the leakage prevention effect. I do. Since the retightening effect is small, once the compression ratio decreases, the cylinder part must be immediately disassembled to replace the packing. When a part of the plunger is worn, the entire plunger starts to wear rapidly. Therefore, an increase in the number of packings does not significantly increase the time required for changing the packing, that is, the effect of extending the life of the packing.
[0006]
[Problems to be solved by the invention]
The present invention has been made based on such a technical background, and achieves the following objects.
[0007]
An object of the present invention is to provide a small-sized plunger-type compressor sealing device using a rectangular packing.
[0008]
It is another object of the present invention to provide a sealing device for a plunger-type compressor that extends the life of a rectangular packing when used in combination with a U packing.
[0009]
It is still another object of the present invention to provide a sealing device for a plunger type compressor which extends the holding time of the sealing performance of a rectangular packing without increasing the sealing space.
[0010]
It is still another object of the present invention to provide a sealing device for a plunger-type compressor, which can extend the holding time of the sealing performance of a rectangular packing at a low cost.
[0011]
Still another object of the present invention is to provide a sealing device for a plunger-type compressor which can reduce the cost.
[0012]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above problems.
[0013]
The sealing device of the plunger compressor according to the first aspect of the present invention includes:
A cylinder formed in the cylinder block;
A plunger that reciprocates by sliding on the inner surface side of the cylinder ;
A low-pressure side packing that is inserted into the space between the plunger and the cylinder and has a large radial compression resistance;
A U packing which is inserted into a space between the plunger and the cylinder and has a small radial compression resistance and is arranged on the high pressure side of the low pressure side packing;
In a sealing device for a plunger-type compressor, comprising a tightening means for tightening the low-pressure side packing in an axial direction,
The low-pressure side packing in cross section a rectangle, the low-pressure side packing least two bodies are used, the U spacer packing formed Ri der only one body, and between the low pressure side packing an elastic material It is characterized by being interposed.
[0017]
The sealing device for a plunger type compressor according to the second aspect of the present invention,
The low-pressure side packing is characterized in that at least one selected from the group consisting of carbon fluoride, polytetrafluoroethylene, and glass fiber is used.
[0018]
Sealing device the plunger-type compressor of the present invention is inserted into the space between the plunger and the low-pressure side packing and plunger and the cylinder of a suitable number greater resistance to compressive forces of the inserted radially into the space between the cylinder U packing resistant radial compressive forces are smaller disposed in the high-pressure side of the low pressure side packing appropriate number corresponding to the appropriate number of low-pressure side packing is used. The main packing withstand radial compressive forces are larger low-pressure side packing, can be cross section used rectangular rectangular packing. The packing withstand radial compressive forces are small, it is possible to use a U-packing.
[0019]
Well and recovered easily U packing adhesion to the plunger for resistance to compressive force is small in the radial direction, the pressure drop effect is large relative to the low pressure side i.e. rectangular packing side. For this reason, the fluid pressure entering between the rectangular packing and the plunger is low due to the head drop effect on the high pressure side of the U packing. The U packing which receives the pressure of the high-pressure compressed fluid inward in the radial direction has good resilience and has a relatively longer life than the low-pressure packing. Further, the U packing is hardly worn due to its structure. That, U packings, the but susceptible to wear because compression strain in the radial direction is larger sliding surface of the order rectangular packing is a low pressure of the fluid pressure, dust, hardly fine particles enters, little vibration by pressure drop Since shear failure is less likely to occur , wear is less likely as a result .
[0020]
For this reason, since solid matter does not easily enter the sliding surface between the plunger and the low-pressure side packing, wear of the plunger is reduced. By synchronizing the life of the high-pressure side and the low-pressure side packing, the overall life can be extended.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the sealing device of the plunger type compressor of the present invention will be described. FIG. 1 is a front sectional view showing an embodiment of a sealing device for a plunger compressor according to the present invention. As shown in FIG. 2, the compressor 1 has a crankshaft 2 connected to a suitable prime mover (not shown) inside. A plunger 8 is connected to the crankshaft 2 via a crank 3, a pin 4, a slider 5, a connecting rod 6, a coupling 7, and the like.
[0022]
The plunger 8 is fitted on a cylinder 10 formed in a cylinder block 9. The plunger 8 is provided to be able to reciprocate substantially coaxially in the cylinder 10. The plunger 8 is used as a piston for compressing a compressed fluid such as compressed air or compressed liquid, as described later. The suction port 11 is a suction port for sucking a fluid.
[0023]
The suction valve mechanism 12 is a valve mechanism for sucking the fluid sucked from the suction port 11 and closing it during compression. The discharge port 13 is a discharge port that discharges the compressed fluid. The discharge valve mechanism 14 is a discharge valve mechanism for this purpose. The compression section 15 between the suction port 11 and the discharge port 13 has a compression chamber 16. The leading end of the plunger 8 enters the compression chamber 16 and moves forward and backward.
[0024]
As shown in detail in FIG. 1, a main packing 20 and a U packing 21 are arranged between the plunger 8 and the cylinder 10 at intervals in the reciprocating motion direction (axial direction) of the plunger 8. Each main packing 20 has a large sliding area between the outer peripheral surface 22 of the plunger 8 and a small compressive strain when a compressive force is applied in the radial direction, and has poor compressive deformation in both the radial direction and the axial direction. . The U packing is rich in radial compressive deformation even if the sliding area is large and the radial compressive force is small.
[0025]
Between the plunger 8 having a polished cylindrical outer peripheral surface 22 and the cylinder 10 having a polished cylindrical inner peripheral surface 23, four main packings 20, 20, 20, 20 are spaced apart in the direction of movement, that is, in the axial direction. And are arranged. A spacer 24 made of an elastic material is interposed between the two main packings 20 adjacent in the sliding direction. As the elastic material of the spacer 24 , polytetrafluoroethylene is used. Polyimide carbon, various elastomers, and the like can be used instead of polytetrafluoroethylene . The cross section of each main packing 20 is square, rectangular, and rectangular. This rectangle may be substantially rectangular, and the periphery is chamfered.
[0026]
A packing holder 26 having a low-pressure side formed on a plane perpendicular to the axis is provided at an end on the high pressure side of the group of main packing groups 20G. The packing retainer 26 is fitted between the cylinder 10 and the plunger 8. The high pressure side surface of the main packing 20 on the high pressure side is in close contact with the surface perpendicular to the axis of the packing retainer 26. The packing retainer 26 is in pressure contact with a small diameter portion 10 a of a part of the cylinder 10. The low pressure side end face of the low pressure side packing retainer 25 is received by the high pressure side end face of the tightening slide tube 27.
[0027]
The re-tightening slide tube 27 having an external thread cut on the outer peripheral surface is screwed with a female screw cut on the inner peripheral surface of the cylinder 10. The rotating tightening slide tube 27 advances and retreats in the reciprocating direction of the plunger 8. One U packing 21 is arranged on the high pressure side of the packing holder 26. The U packing 21 is sandwiched between the inner peripheral surface of the packing retainer 26 and the cylindrical outer peripheral surface 22 of the plunger. The U packing 21 has a U-shaped cross section of one of two cross sections appearing at positions different by 180 degrees. The U-shaped concave surface faces the high pressure side. That is, the letter U is oriented in the axial direction, and the upper side of the letter U is the high-pressure side.
[0028]
The cylinder 10 is provided with a lubricating oil injection hole 29 for introducing an oil mist or oil mixed with lubricating air to the peripheral surface of the plunger 8. Ring grooves 30 and 31 are provided on the outer peripheral surface and the inner peripheral surface of the re-tightening sliding tube 27, and both ring grooves are connected by a connection hole 32. A seal ring 33 is interposed between the tightening slide tube 27 and the plunger body 8.
[0029]
The material of the main packing 20 is at least one selected from the group consisting of carbon fluoride, polytetrafluoroethylene , and glass fiber.
[0030]
Next, the operation of the first embodiment will be described. A part of the plunger 8 is supported by elastic main packing 20 and U packing 21. The plunger 8 which receives the reciprocating motion force transmitted through the coupling 7 to the connecting rod 6 which reciprocates in conjunction with the rotational motion of the crankshaft 2 has a slight angle but a swing angle in which the direction is unlimited. Vibrates radially. The high-pressure fluid acts on the concave surface of the U packing 21 and presses the sliding surface, which is the inner peripheral surface of the U packing 21, against the outer peripheral surface 22 of the plunger 8.
[0031]
The U packing 21 originally has better sealing performance than the main packing 20. The area of the sliding surface of the U packing 21 sliding on the plunger 8 is equal to or larger than the area of the sliding surface of each main packing 20. U-packing 21, taking into account the pressing force due to such a large compressive force by the high pressure fluid, the initial compressive force is provided for appropriately. The U-packing 21 is provided so as to be easily expanded in the axial direction and the radial direction in the space 28 where there is some room, so that the U-packing 21 is less likely to receive an excessive compressive force due to the reciprocating motion of the plunger 8.
[0032]
Although the sealing performance of the U-packing 21 is originally excellent, the leakage of the high-pressure fluid cannot be completely prevented. The pressure fluid that has permeated the sliding surface of the U packing 21 at a high pressure and reached the main packing 20 is reduced in pressure by the resistance received on the leakage surface of the U packing 21. The relatively low pressure fluid acts on the plane perpendicular to the axis and the sliding surface of the main packing 20. The radial compressive force that the main packing 20 receives from the pressurized fluid is relatively small. The main packing 20 is initially compressed in the axial direction by a tightening sliding tube 27 as a tightening means. Due to this compressive force, the stress between the sliding surface of the main packing 20 and the cylindrical outer peripheral surface of the plunger 8 is initially adjusted. The adhesion between the inner peripheral surface of the main packing 20 and the outer peripheral surface of the plunger 8 is large. Pressure fluid leaking to the sliding surface, such as this is, leak rate for undergoing a pressure drop by U-packing 21 is slow.
[0033]
Mud fluid in the construction site, there is a case in a cement milk. Generally, when the dust and solids in the pressurized fluid enter the sliding surface, the main packing group wears violently.However, the wear due to the dust in the leakage fluid at the main packing group where the pressure is reduced by the U packing is: Significantly reduced.
[0034]
The wear of each main packing 20 is more intense than the U packing 21. When the inner peripheral surface side of the main packing group 20G is deteriorated and the sealing performance is deteriorated, the sliding tube for tightening 27 is rotated clockwise. By １ ／ rotation, the sliding tube for tightening 27 advances by 0.5 mm. Each main packing 20 receives compression and expands in the radial direction due to the forward movement of the tightening slide tube 27, and the pressure contact force between the main packing 20 and the plunger 8 is restored. Since the time when the main packing 20 must be replaced and the time when the performance of the U-packing 21 deteriorates coincide with each other, the overall life is greatly extended.
Experimental results When the discharge rate exceeds 1 m / s, the life is extremely shortened. Only the V-packing is used. In the experiment using the same type of pump as the pump and reducing the V-packing by one, and instead using one U-packing on the high pressure side Even when the discharge capacity was increased to 2 m / s, the life was not sharply shortened. Conventionally, when the discharge capacity is increased to 2 m / s, a rectangular packing, that is, a gland packing is used without using a V packing to prevent a sudden shortening of the life. However, when the solid content in the muddy water enters the sliding surface, the plunger is worn. In the pump of the present invention in which the U packing is provided on the high pressure side, since the U packing prevents movement of the muddy water to the gland packing side, the abrasion of the plunger is small. The use of U-packing has doubled the life.
Estimation of action The action of the combined use of the U main packings, which has significantly increased the durability time and improved the pump performance, is estimated as follows. U packing has good adhesion to the plunger. The U-packing, which has a high elasticity inward in the radial direction, is on the high-pressure side and is easily worn by solids in muddy water, but its elastic deformation does not rapidly deteriorate the adhesion. For this reason, the solid component in the muddy water is effectively prevented from moving to the low pressure side by the U packing for a long time.
[0035]
The pressure of the fluid that has permeated the sliding surface between the U packing and the plunger and leaked to the main packing side is reduced by the permeation pressure when the liquid permeates the sliding surface between the U packing and the plunger. I have. Such a head pressure drop is a characteristic of the U packing. Since the pressure that penetrates between two adjacent main packings is reduced in this way, between the two adjacent main packings and between the main packing and the plunger that are strongly pressed in the axial direction by the fastening means 27. There is no gap on the sliding surface. If the pressure P that penetrates between two adjacent main packings is high, the gap between the sliding surfaces becomes larger, and the main packing is greatly distorted and vibration deformation is amplified in the main packing. The clearance between the moving surfaces increases. Since such a plurality of main packings are not made rigid, one reciprocation of the plunger receives one intense vibration force. Since rubber is vulnerable to such vibrations, portions are gradually missing. On the other hand, a gap does not vibrate due to the low-pressure fluid that penetrates the boundary surface between two adjacent main packings that are fastened by the fastening means. That is, since the packing group is made rigid, each main packing receives the sliding friction from the plunger and undergoes an abrasion action based on the sliding friction theory, but does not receive a weakening action due to a strong vibration force, so that wear is suppressed. .
[0036]
For this reason, the solid content entering the sliding surface between the main packing and the plunger is reduced, the wear of the plunger is reduced, and the life of the plunger is extended.
[0037]
[Other embodiments]
In the embodiment of the sealing device for the plunger type compressor according to the present invention, the combination of the numbers of the U main and both packings is free. Changes are made depending on the packing material, pressure resistance limit, and type of pressure fluid.
[0038]
【The invention's effect】
The sealing device of the plunger type compressor of the present invention can respond to the type of the compressed fluid and the compression ratio (the degree of high pressure) by the combination of the numbers of the U main packings. Further, the material can be arbitrarily selected depending on the combination of the numbers of the U main packings. By synchronizing the lives of both U main packings while enabling such measures, the retention time of the sealing performance can be greatly extended. Do not increase the length of the sealing space.
[Brief description of the drawings]
FIG. 1 is a front sectional view showing Embodiment 1 of a sealing device for a plunger compressor according to the present invention.
FIG. 2 is a front cross-sectional view showing the entire configuration of the plunger compressor according to the present invention.
[Explanation of symbols]
8 plunger 9 cylinder block 10 cylinder 20 main packing 21 U packing 27 sliding pipe for tightening (tightening means)

Claims (2)

A cylinder formed in the cylinder block;
A plunger that reciprocates by sliding on the inner surface side of the cylinder ;
A low-pressure side packing that is inserted into the space between the plunger and the cylinder and has a large radial compression resistance;
A U packing which is inserted into a space between the plunger and the cylinder and has a small radial compression resistance and is arranged on the high pressure side of the low pressure side packing;
In a sealing device for a plunger-type compressor, comprising a tightening means for tightening the low-pressure side packing in an axial direction,
The low-pressure side packing in cross section a rectangle, the low-pressure side packing least two bodies are used, the U spacer packing formed Ri der only one body, and between the low pressure side packing an elastic material A sealing device for a plunger compressor, which is interposed. In claim 1 ,
A sealing device for a plunger-type compressor, wherein the low-pressure side packing uses at least one selected from the group consisting of carbon fluoride, polytetrafluoroethylene, and glass fiber.

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