High-pressure small-flow oil-free double-acting plunger compressor

Abstract

The invention provides a high-pressure small-flow oil-free double-acting plunger compressor, and aims to solve the problem that a compressor in the prior art cannot meet the requirements of small flow, high pressure and no oil required by a gas-phase medium at the same time. The hydraulic cylinder comprises a motor, a crank pin, a connecting rod, a crosshead frame, a plunger, a cylinder cover, a transition section, a crankcase, a cylinder sleeve, a valve cover and other main components. An inner cavity of the cylinder cover is divided into two independent cavities, one cavity is the air inlet cavity connected with the air inlet pipeline, the other cavity is the exhaust cavity connected with the air outlet pipeline, the crank pin is of an eccentric two-section cylinder structure, the eccentric distance is L, and therefore when the motor drives the crank pin to rotate, the crank pin is driven by the motor to rotate. The crosshead frame and the plunger are driven by the connecting rod to reciprocate in the cylinder sleeve, so that double-acting compression and discharge of gas are realized in a compression cavity formed by the plunger, the cylinder sleeve and the valve cover, and the requirements of high pressure, small flow and oil-free environment of a gas-phase medium in the prior art can be met.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of compressors, in particular to a high-pressure small-flow oil-free double-acting plunger compressor. BACKGROUND

[0002] At present, small-flow plunger structures are mostly used in hydraulic systems, and common structures realize volume change through cooperation of swash plates and plungers, so as to complete liquid suction and discharge. Although such structures can realize small-flow delivery, the pressure is usually low (generally not more than 1 MPa), and there is a risk of oil pollution, so the structures are not suitable for occasions with high requirements for gas cleanliness.

[0003] In the energy field, such as extraction of rare gases such as argon, neon, krypton and xenon from natural gas, or compression of hydrogen in a small-flow micro hydrogen station, the compressor needs to have the characteristics of high pressure, small flow and oil-free operation. Therefore, in view of this problem, a solution needs to be provided. SUMMARY

[0004] The application provides a high-pressure small-flow oil-free double-acting plunger compressor to meet the working condition requirements of high pressure and small flow, and the whole compressor is oil-free, which ensures the cleanliness of the gas and avoids pollution caused explosion.

[0005] The technical scheme adopted by the application is as follows: A high-pressure small-flow oil-free double-acting plunger compressor comprises a motor, a crank pin, a connecting rod, a crosshead frame, a plunger, a cylinder sleeve, a cylinder cover, a transition section, a crankcase and a valve cover; One end of the crank pin is connected with an output shaft of the motor, and the other end is connected with one end of the connecting rod through a roller bearing; The other end of the connecting rod is connected with the crosshead frame through a bearing and a connecting rod pin; The plunger is fixedly connected with the crosshead frame through a screw; The cylinder cover, the transition section and the crankcase are connected to form a compressor shell through long bolts; The plunger is arranged in the cylinder sleeve, the cylinder sleeve is installed in the shell, and the valve cover is installed between the cylinder sleeve and the cylinder cover; The valve cover is provided with an air inlet valve assembly and an air outlet valve assembly; The crank pin has an eccentric two-cylinder structure, and the eccentric distance is L, so that when the motor drives the crank pin to rotate, the crosshead frame and the plunger are driven to reciprocate in the cylinder sleeve through the connecting rod, so as to realize double-acting compression and discharge of the gas in the compression cavity formed by the plunger, the cylinder sleeve and the valve cover.

[0006] Further, the air inlet valve assembly comprises an air inlet valve plate and an air inlet limiting plate, both of which are fixed on the valve cover by a first rivet. The exhaust valve assembly comprises an exhaust valve plate and an exhaust limiting plate, both of which are fixed on the valve cover by a second rivet.

[0007] Further, the internal cavity of the cylinder cover is divided into two independent chambers, which are connected to the air inlet pipeline as an air inlet chamber and to the air outlet pipeline as an exhaust chamber.

[0008] Further, O-rings are arranged between the cylinder sleeve and the transition section and the crankcase for sealing; O-rings are arranged between the crankcase and the transition section and between the transition section and the cylinder cover for sealing; and O-rings are arranged between the cylinder cover and the valve cover for sealing.

[0009] Further, a piston ring is arranged between the plunger and the cylinder sleeve for sealing, and a guide ring is arranged for sealing and guiding.

[0010] Further, a packing is arranged at the driving shaft extension of the crankshaft for sealing, and the packing is compressed by a pressing plate.

[0011] Further, all chambers and moving parts of the compressor that contact gas are free of oil lubrication, and the roller bearings and bearings adopt double-sided sealing bearings.

[0012] Further, one end of the cylinder sleeve is a free end, which can freely expand towards the crankcase when heated.

[0013] Further, the bottom of the plunger is provided with a groove, and the crosshead frame is provided with a boss matched with the groove, and the plunger is fastened and connected with the crosshead frame by screws.

[0014] The beneficial effects of the present application relative to the prior art are as follows: 1) Oil-free operation: all chambers contacting gas are free of oil, and bearings adopt double-sided sealing structure to ensure clean gas; 2) Thermal compensation design: the cylinder sleeve can freely expand with heat, without the need for an additional cooling system, simplifying the structure; 3) Wide application range: meets the needs of high pressure and small flow, and meets the needs of oil-free environment, and can be used for hydrogen, rare gas and other gas media with high cleanliness requirements. BRIEF DESCRIPTION OF DRAWINGS

[0015] Fig. 1 is a schematic diagram of the internal structure of the present application; Fig. 2 is a schematic diagram of the structure of the cylinder cover in the present application; Fig. 3 is a schematic diagram of the structure of the valve cover in the present application.

[0016] 1, cylinder head; 2, valve cover; 3, transition section; 4, cylinder sleeve; 5, plunger; 6, crankcase; 7, crosshead frame; 8, screw; 9, crank pin; 10, roller bearing; 11, connecting rod; 12, bearing; 13, connecting rod pin; 14, guide ring; 15, first O-ring; 16, piston ring; 17, second O-ring; 19, long bolt; 20, third O-ring; 21, pressing plate; 23, packing; 25, second rivet; 26, exhaust port limiting piece; 27, exhaust port valve piece; 28, first rivet; 29, intake port valve piece; 30, intake port limiting piece. DETAILED DESCRIPTION

[0017] The specific embodiments of the present application are described below with reference to the accompanying drawings.

[0018] The present application provides a high-pressure small-flow oil-free double-acting plunger compressor, aiming at solving the problem that the compressor of the prior art cannot simultaneously meet the requirements of small flow, high pressure and oil-free for gas-phase medium.

[0019] As shown in Figs. 1 to 3 the present application mainly includes a motor, a crank pin 9, a connecting rod 11, a crosshead frame 7, a plunger 5, a cylinder sleeve 4, a cylinder head 1, a transition section 3, a crankcase 6 and a valve cover 2; One end of the crank pin 9 is connected with an output shaft of the motor, and the other end is connected with one end of the connecting rod 11 through a roller bearing 10; The other end of the connecting rod 11 is connected with the crosshead frame 7 through a bearing 12 and a connecting rod 11 pin; The plunger 5 is fixedly connected with the crosshead frame 7 through a screw 8; The cylinder head 1, the transition section 3 and the crankcase 6 are connected to form a compressor shell through a long bolt 19; The plunger 5 is arranged in the cylinder sleeve 4, the cylinder sleeve 4 is installed in the shell, and the valve cover 2 is installed between the cylinder sleeve 4 and the cylinder head 1; The valve cover 2 is provided with an intake valve assembly and an exhaust valve assembly; The crank pin 9 has an eccentric two-segment cylinder structure, and the eccentricity is L, so that when the motor drives the crank pin 9 to rotate, the connecting rod 11 drives the crosshead frame 7 and the plunger 5 to reciprocate in the cylinder sleeve 4, thereby realizing double-acting compression and discharge of gas in the compression cavity formed by the plunger 5, the cylinder sleeve 4 and the valve cover 2.

[0020] Further, the intake valve assembly includes an intake port valve piece 29 and an intake port limiting piece 30, which are fixed on the valve cover 2 through a first 15 rivet; The exhaust valve assembly comprises an exhaust port valve sheet 27 and an exhaust port limiting sheet 26, which are fixed on the valve cover 2 by a second rivet 17.

[0021] Further, the internal cavity of the cylinder cover 1 is divided into two independent chambers, which are connected with the air inlet pipeline as the air inlet chamber and with the air outlet pipeline as the air outlet chamber.

[0022] Further, O-rings are arranged between the cylinder sleeve 4 and the transition section 3 and the crankcase 6 for sealing; O-rings are arranged between the crankcase 6 and the transition section 3 and between the transition section 3 and the cylinder cover 1 for sealing; and O-rings are arranged between the cylinder cover 1 and the valve cover 2 for sealing.

[0023] Further, a piston ring 16 is arranged between the plunger 5 and the cylinder sleeve 4 for sealing, and a guide ring 14 is arranged for sealing and guiding.

[0024] Further, a packing 23 is arranged at the driving shaft extension of the crankshaft 9 and the crankcase 6 for sealing, and the packing 23 is compressed by a pressing plate 21.

[0025] Further, all the chambers and moving parts of the compressor that contact with gas are free of oil lubrication, and the roller bearing 10 and the bearing 12 are double-sided sealed bearings 12.

[0026] Further, one end of the cylinder sleeve 4 is a free end, which can freely expand towards the crankcase 6 when heated.

[0027] Further, a groove is arranged at the bottom of the plunger 5, and a boss is arranged on the crosshead frame 7 to cooperate with the groove, and the plunger 5 is fastened and connected with the crosshead frame 7 by a screw 8.

[0028] The specific structure and working principle of the present application are as follows: The compressor comprises a motor, a crankshaft 9, a connecting rod 11, a crosshead frame 7, a plunger 5, a cylinder cover 1, a transition section 3, a crankcase 6, a cylinder sleeve 4 and a valve cover 2.

[0029] The crankcase 6, the transition section 3 and the cylinder cover 1 are fastened in series by a plurality of long bolts 19 to form a main body shell of the compressor. The cylinder sleeve 4 is installed between the shell and the plunger 5, and the valve cover 2 is installed between the cylinder cover 1 and the cylinder sleeve 4.

[0030] One end of the crank pin 9 is fixed to the output shaft of the motor by means of a key or the like to receive power. The other end (eccentric end) of the crank pin 9 is hinged to the large end of the connecting rod 11 by means of a roller bearing 10. The small end of the connecting rod 11 is hinged to the crosshead frame 7 by means of a bearing 12 and a connecting rod pin 13. The tail of the plunger 5 is fixed to the crosshead frame 7 by means of a screw 8, so that the plunger 5, the crosshead frame 7 and the connecting rod 11 form a reciprocating whole. The working part of the plunger 5 extends into the inner hole of the cylinder sleeve 4, and the two form a sliding pair.

[0031] The axis of the crank pin 9 and the axis of the motor connecting end have an eccentricity L. When the motor drives the crank pin 9 to rotate, the eccentric end thereof moves in a circular motion with L as the radius, and further drives the crosshead frame 7 and the plunger 5 to move linearly in the cylinder sleeve 4.

[0032] The inner cavity of the cylinder head 1 is divided into two independent chambers: one is an intake chamber connected to the intake pipeline, and the other is an exhaust chamber connected to the exhaust pipeline.

[0033] The valve cover 2 is provided with valve groups for controlling intake and exhaust respectively. Specifically, the intake valve group includes an intake valve plate 29 and a limiting plate 30 for limiting the opening stroke of the intake valve plate 29, and the two are fixed to the valve cover 2 by means of a first rivet 28 and correspond to the intake chamber of the cylinder head 1. The exhaust valve group includes an exhaust valve plate 27 and a limiting plate 26 for limiting the opening stroke of the exhaust valve plate 27, and the two are fixed to the valve cover 2 by means of a second rivet 25 and correspond to the exhaust chamber of the cylinder head 1.

[0034] The working process of the compressor is as follows: Due to the center offset L of the two cylindrical bodies of the crank pin 9, when the motor end is connected to rotate, the center of the other end moves in a circular motion with L as the radius, so that the position of the connecting rod 11 changes. When the connecting rod 11 drives the crosshead frame 7 to move, the plunger 5 installed on the crosshead frame 7 can change its position in the cylinder sleeve 4, and the volume of the compression chamber continuously increases and decreases. When the volume of the compression chamber increases, the intake valve plate 29 is opened and tightly attached to the limiting plate 30, and at this time the gas is sucked in; when the compression chamber decreases to a certain volume, the exhaust valve plate 27 is opened and tightly attached to the limiting plate 26, and the gas is discharged, realizing the entire process from suction to compression and discharge of the gas.

[0035] The sealing system of the embodiment is as follows: To ensure the sealing performance of the compressor under high pressure and the clean requirement of oil-free operation, sealing elements are arranged at key positions: A first O-ring 15 is arranged between the outer wall of the cylinder sleeve 4 and the matching hole of the transition section 3 and the crankcase 6 for static sealing; The joint surface of the crankcase 6 and the transition section 3, and the joint surface of the transition section 3 and the cylinder head 1 are both provided with a second O-ring 17 for static sealing.

[0036] The joint surface of the cylinder head 1 and the valve cover 2 is provided with a third O-ring 20 for static sealing; The dynamic sealing between the plunger 5 and the cylinder sleeve 4 is realized by the five-stage piston ring 16 arranged on the plunger 5. Meanwhile, the guiding ring 14 is arranged on the plunger 5, which provides support and guidance for the plunger 5 and plays a role of auxiliary sealing and guidance.

[0037] The key groove head of the crankcase 6 and the crank pin 9 is sealed by the packing 23, and the packing is compressed by the pressing plate 21 and the bolt 22, so that the gas at the rotating shaft is zero leakage.

[0038] The high-pressure small-flow oil-free double-acting plunger compressor described in the embodiment has compact structure, all the chambers in contact with the compressed gas are realized oil-free lubrication, the combination of the multi-stage static sealing and reliable dynamic sealing ensures the sealing property under high pressure and the cleanliness of the gas, and is particularly suitable for rare gas compression, micro hydrogenation station and other occasions with extremely high requirements on the quality of the gas.

[0039] The above description is an explanation of the present application, not a limitation of the present application, the scope of the present application is defined in the claims, and any form of modification within the protection scope of the present application can be made.

Claims

1. A high-pressure, low-flow, oil-free, double-acting plunger compressor, characterized in that: include Motor, crank pin (9), connecting rod (11), crosshead frame (7), plunger (5), cylinder liner (4), cylinder head (1), transition section (3), crankcase (6), and valve cover (2); One end of the crank pin (9) is connected to the output shaft of the motor, and the other end is connected to one end of the connecting rod (11) through a roller bearing (10); The other end of the connecting rod (11) is connected to the crosshead frame (7) via a bearing (12) and a connecting rod pin (13); The plunger (5) is fixedly connected to the crosshead frame (7) by screws (8); The cylinder head (1), transition section (3) and crankcase (6) are connected by long bolts (19) to form the compressor housing; The plunger (5) is disposed inside the cylinder liner (4), the cylinder liner (4) is installed inside the outer shell, and the valve cover (2) is installed between the cylinder liner (4) and the cylinder cover (1); The valve cover (2) is provided with an intake valve assembly and an exhaust valve assembly; The crank pin (9) has an eccentric two-section column structure with an eccentricity of L. When the motor drives the crank pin (9) to rotate, the crosshead frame (7) and the plunger (5) are driven to reciprocate in the cylinder liner (4) through the connecting rod (11), thereby realizing the double-acting compression and discharge of gas in the compression chamber formed by the plunger (5), the cylinder liner (4) and the valve cover (2).

2. The high-pressure, low-flow, oil-free, double-acting plunger compressor as described in claim 1, characterized in that: The intake valve assembly includes an intake valve plate (29) and an intake limiting plate (30), both of which are fixed to the valve cover (2) by a first rivet (28); The exhaust valve assembly includes an exhaust port valve plate (27) and an exhaust port limiting plate (26), both of which are fixed to the valve cover (2) by a second rivet (25).

3. The high-pressure, low-flow, oil-free, double-acting plunger compressor as described in claim 1, characterized in that: The internal cavity of the cylinder head (1) is divided into two independent chambers, which serve as the intake chamber connected to the intake pipe and the exhaust chamber connected to the exhaust pipe, respectively.

4. The high-pressure, low-flow, oil-free, double-acting plunger compressor as described in claim 1, characterized in that: A first O-ring (15) is provided between the cylinder liner (4) and the transition section (3) and the crankcase (6) for sealing; a second O-ring (17) is provided between the crankcase (6) and the transition section (3) and between the transition section (3) and the cylinder head (1) for sealing; a third O-ring (20) is provided between the cylinder head (1) and the valve cover (2) for sealing.

5. The high-pressure, low-flow, oil-free, double-acting plunger compressor as described in claim 1, characterized in that: A five-stage piston ring (16) is provided between the plunger (5) and the cylinder liner (4) for sealing, and a guide ring (14) is provided to serve both sealing and guiding functions.

6. The high-pressure, low-flow, oil-free, double-acting plunger compressor as described in claim 1, characterized in that: The crankcase (6) and the drive shaft extension of the crank pin (9) are sealed with packing (23), and the packing (23) is pressed by a pressure plate (21).

7. The high-pressure, low-flow, oil-free, double-acting plunger compressor as described in claim 1, characterized in that: All chambers and moving parts of the compressor that come into contact with gas are oil-free, and the roller bearings (10) and bearings (12) are double-sided sealed bearings.

8. The high-pressure, low-flow, oil-free, double-acting plunger compressor as described in claim 1, characterized in that: One end of the cylinder liner (4) is a free end and can expand freely toward the crankcase (6) when heated.

9. A high-pressure, low-flow, oil-free, double-acting plunger compressor as described in claim 1, characterized in that: The plunger (5) has a groove at its bottom and a boss that matches it on the crosshead frame (7). The plunger (5) is fastened to the crosshead frame (7) by screws (8).

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