A hydraulically driven cryogenic reciprocating pump capable of reducing the influence of low temperature on the piston rod seal

Abstract

The present invention discloses a hydraulically driven low-temperature reciprocating pump capable of reducing the influence of low temperature on the piston rod seal, comprising a cylinder body, a pump body and a piston rod, characterized in that: a low-temperature medium storage tank is provided inside the pump body, and an end cover fixedly connected to the pump body is provided at the opening of the pump body; the cylinder body is arranged above the pump body, one end of the piston rod passes through the end cover and extends into the cylinder body cavity, and reciprocates in the cylinder body cavity; a rubber sealing ring for oil sealing is provided on the piston rod; and a heat-insulating and radiation-proof protective sleeve is provided between the cylinder body and the end cover. The present invention has many advantages such as ensuring the sealing life of the rubber sealing ring, preventing frost at the pump body opening, and reducing the friction between the piston cylinder and the cavity.

Description

Technical Field

[0001] The invention relates to the field of hydraulically driven cryogenic reciprocating pumps, in particular to a hydraulically driven cryogenic reciprocating pump capable of reducing the influence of low temperature on a piston rod seal. Background Art

[0002] Hydraulic driven reciprocating pumps are widely used. Compared with traditional reciprocating pumps, the crank-connecting rod mechanism is removed and the hydraulic cylinder drive is adopted. It is hydraulically controlled, has a long stroke and low stroke frequency, and greatly improves the working performance. However, hydraulic driven reciprocating pumps also require a piston rod that performs axial reciprocating motion in the pump working chamber.

[0003] The hydraulically driven reciprocating pumps described above are particularly useful in cryogenic pumps involving extremely high pressures, such as cryogenic pumps for media such as liquid nitrogen or liquid methane, where the operating environment temperature is extremely low.

[0004] The hydraulically driven cryogenic reciprocating pump has a drive end connected to the storage tank of the cryogenic pump. The piston rod seal at the drive end is generally sealed with an oil seal. Since the piston rod at the drive end will be affected by the low temperature of the cryogenic medium, the surface temperature of the piston rod at the drive end will decrease, which will cause the oil seal to be affected by the low temperature, reducing the elasticity of the polyurethane or rubber oil seal, making the entire oil seal hard and brittle, and causing the seal to fail, resulting in leakage of hydraulic oil. Existing hydraulically driven cryogenic reciprocating pumps have increased the temperature area by lengthening the piston rod, but due to the increase in the volume of the piston rod and the unchanged hydraulic power, the piston rod activity frequency will decrease, and the seal will still be affected by the low temperature to a certain extent. There is also a way to solve the influence of the connecting rod surface temperature by electric heating, but the structure of the electric heating is relatively complicated. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a hydraulically driven cryogenic reciprocating pump capable of reducing the influence of low temperature on the piston rod seal, thereby solving the problems raised in the above-mentioned background technology.

[0006] In order to achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] A hydraulically driven low-temperature reciprocating pump with the function of reducing the influence of low temperature on the piston rod seal, comprising a cylinder body, a pump body and a piston rod, the pump body comprising a vacuum storage tank and a pump body end cover, the opening of the vacuum storage tank being fixedly connected to the pump body end cover; the cylinder body is arranged above the pump body, one end of the piston rod extends through the pump body end cover to the cylinder body cavity, and reciprocates in the cylinder body cavity; a sealing ring for oil sealing is provided on the piston rod; a heat-insulating and radiation-proof protective cover is provided between the cylinder body and the pump body end cover.

[0008] Preferably, the heat-insulating and radiation-proof protective cover comprises a connecting portion and an extending portion, wherein the connecting portion is used to connect the cylinder body and the pump body end cover, and the extending portion matches the opening of the pump body end cover.

[0009] Preferably, the extension portion is embedded in the opening of the pump body end cover, a first groove is formed at the bottom end of the connecting portion, a first sealing gasket is arranged in the first groove, and the bottom end of the connecting portion is sealed to the top end of the pump body end cover through the first sealing gasket.

[0010] Preferably, a second groove is formed at the top of the connecting portion, a second sealing gasket is arranged in the second groove, and the connecting portion is sealed and connected to the bottom end of the cylinder body through the second sealing gasket.

[0011] Preferably, the heat-insulating and radiation-proof protective sleeve, the cylinder body and the pump body end cover are all provided with bolt holes, and the heat-insulating and radiation-proof protective sleeve, the cylinder body and the pump body end cover are fixed by bolts passing through the bolt holes.

[0012] Preferably, the inner wall of the heat-insulating and radiation-proof protective sleeve does not contact the surface of the piston rod.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] By adding a heat-insulating and radiation-proof protective sleeve between the cylinder body and the pump body end cover, the influence of the low temperature of the pump body end cover on the piston rod oil seal in the cylinder body can be reduced, the sealing life of the sealing ring can be guaranteed, and the heat leakage and frost at the opening of the pump body end cover can be prevented; the inner wall of the heat-insulating and radiation-proof protective sleeve does not contact the surface of the piston rod, reducing the friction of the piston rod in the cavity. The present invention has many advantages such as ensuring the sealing life of the sealing ring, preventing frost at the pump body opening, and reducing the friction between the piston rod and the cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the present invention;

[0016] Figure 2 For the present invention Figure 1 Enlarged structural diagram at A in the middle.

[0017] In the figure: 1-cylinder body, 2-pump body, 3-piston rod, 4-pump body end cover, 5-sealing ring, 6-thermal insulation and radiation protection cover, 7-vacuum storage tank, 8-connecting part, 9-extension part, 10-first groove, 11-bolt hole, 12-bolt, 13-first sealing gasket, 14-second groove, 15-second sealing gasket, 16-liquid outlet pipe, 17-liquid outlet. Specific implementation plan

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0019] Reference Figure 1 The present invention provides a technical solution: a hydraulically driven cryogenic reciprocating pump with the function of reducing the influence of low temperature on the piston rod seal, comprising a cylinder body 1, a pump body 2 and a piston rod 3, the pump body 2 comprising a vacuum storage tank 7 and a pump body end cover 4, the vacuum storage tank 7 is filled with a cryogenic medium with a very low temperature, such as liquid nitrogen or liquid methane; the opening of the pump body 2 is provided with a pump body end cover 4; the pump body end cover 4 is fixedly connected to the open end of the pump body 2 by screws, and the pump body end cover is provided with a plurality of screw holes distributed in a circular array, and does not pass through The liquid outlet pipe 13, the pump cylinder 1 is arranged above the pump body 2, one end of the piston rod 3 passes through the pump end cover 4 and extends into the cavity of the cylinder 1, and reciprocates in the cavity of the cylinder 1; a heat-insulating and radiation-proof protective sleeve 6 is arranged between the cylinder 1 and the pump end cover 4, and the material of the heat-insulating and radiation-proof protective sleeve 6 has good heat-insulating performance, and epoxy resin, electrical bakelite and other materials can be used. A sealing ring 5 is arranged on the piston rod 3, and the sealing ring 5 is located in the groove at the top of the connecting part 8, and a gap is left at one end in the groove to facilitate the sealing ring 5 Tighten, and oil seal is performed by applying clean grease to the contact surface of the sealing ring 5 and the piston rod 3; the heat-insulating and radiation-proof protective sleeve 6 includes a connecting portion 8 and an extension portion 9, the connecting portion 8 and the extension portion 9 are connected as a whole, and the extension portion 9 is embedded in the opening of the pump body end cover 4, and a first groove 10 is opened at the bottom of the connecting portion 8, and a first sealing gasket 13 is arranged in the first groove 10. The bottom end of the connecting portion 8 is sealed and connected to the top of the pump body end cover 4 through the first sealing gasket 13; a second groove 14 is opened at the top of the connecting portion 8, and a second sealing gasket 15 is arranged in the second groove 14. The connecting portion 8 is sealed and connected to the bottom end of the cylinder body through the second sealing gasket 15, and the connecting part of the connecting portion 8 has a gap for the first sealing gasket 13 and the second sealing gasket 15 to be pressed; the heat-insulating and radiation-proof protective sleeve 6, the cylinder body 1 and the pump body end cover 4 are all distributed with a plurality of matching bolt holes 11 in a circular array, and do not pass through the liquid outlet pipe 13, and are fixedly connected by bolts 12 passing through the bolt holes 11.

[0020] A liquid outlet pipe 16 is provided in the pump body 2. The low-temperature medium inside the vacuum storage tank 7 is pressed downward by the piston rod 3, and the low-temperature medium is pressed into the liquid outlet pipe 16, and the low-temperature medium is transported out from the liquid outlet 17. At this time, the temperature of the lower end of the piston rod 3 is extremely low because it is extended into the low-temperature medium. Since the low-temperature medium flows in the liquid outlet pipe 16, the temperature of the part of the pump body end cover 4 located near the liquid outlet pipe 16 is extremely low. Since the pump body end cover 4 does not have good thermal insulation performance, the temperature of the top surface of the pump body end cover 4 close to the liquid outlet pipe 16 is low, while the cylinder body 1 is at room temperature. A heat-insulating and radiation-proof protective sleeve 6 is provided between the pump body end cover 4 and the cylinder body 1, which can reduce the influence of the low temperature on the top surface of the pump body end cover 4 on the sealing part of the sealing ring, prevent the oil seal from failing due to low temperature, ensure the sealing life of the sealing ring, and prevent heat leakage and frost at the opening of the pump body end cover 4; the extension part 9 of the heat-insulating and radiation-proof protective sleeve 6 extends downward to the cavity of the opening of the pump body end cover 4, which can reduce the influence of the low temperature on the lower end of the piston rod 3 on the sealing part to a certain extent, and prevent the sealing failure; the inner wall of the heat-insulating and radiation-proof protective sleeve 6 does not contact the surface of the piston rod 3, thereby reducing the friction of the piston rod 3 when it moves in the cavity.

[0021] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A hydraulically driven cryogenic reciprocating pump capable of reducing the influence of low temperature on the piston rod seal, comprising a cylinder body (1), a pump body (2) and a piston rod (3), characterized in that: The pump body (2) comprises a vacuum storage tank (7) and a pump body end cover (4), wherein an opening of the vacuum storage tank (7) is fixedly connected to the pump body end cover (4); the cylinder body (1) is arranged above the pump body (2), one end of the piston rod (3) passes through the pump body end cover (4) and extends into the cavity of the cylinder body (1), and reciprocates in the cavity of the cylinder body (1); The piston rod (3) is provided with a sealing ring (5) for oil sealing; a heat-insulating and radiation-proof protective sleeve (6) is provided between the cylinder body (1) and the pump body end cover (4), and the inner wall of the heat-insulating and radiation-proof protective sleeve (6) does not contact the surface of the piston rod (3); The heat-insulating and radiation-proof protective sleeve (6) comprises a connecting portion (8) and an extending portion (9), wherein the connecting portion (8) is used to connect the cylinder body (1) and the pump body end cover (4), and the extending portion (9) matches the opening of the pump body end cover (4). A sealing ring (5) is provided on the piston rod (3), and the sealing ring (5) is located in a groove at the top end of the connecting portion (8), and a gap is left at one end in the groove to facilitate the sealing ring (5) to be pressed tightly.

2. A hydraulically driven cryogenic reciprocating pump capable of reducing the influence of low temperature on the piston rod seal according to claim 1, characterized in that: The extension portion (9) is embedded in the opening of the pump body end cover (4); a first groove (10) is formed at the bottom end of the connection portion (8); a first sealing gasket (13) is arranged in the first groove (10); the bottom end of the connection portion (8) is sealedly connected to the top end of the pump body end cover (4) via the first sealing gasket (13).

3. A hydraulically driven cryogenic reciprocating pump capable of reducing the influence of low temperature on the piston rod seal according to claim 1, characterized in that: A second groove (14) is formed at the top of the connecting portion (8), a second sealing gasket (15) is arranged in the second groove (14), and the connecting portion (8) is sealedly connected to the bottom end of the cylinder body (1) via the second sealing gasket (15).

4. A hydraulically driven cryogenic reciprocating pump capable of reducing the influence of low temperature on the piston rod seal according to claim 1, characterized in that: The heat-insulating and radiation-proof protective sleeve (6), the cylinder body (1) and the pump body end cover (4) are all provided with bolt holes (11), and the heat-insulating and radiation-proof protective sleeve (6), the cylinder body (1) and the pump body end cover (4) are fixed by bolts (12) passing through the bolt holes (11).

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