Piston compressor driven by liquid pressure

Abstract

The invention discloses a piston type compressor driven by liquid pressure, which is characterized in that hydraulic and gas compression components are integrated in a cylinder body, a crankshaft rotates to drive a hydraulic piston, then a gas piston is driven by utilizing the characteristic that liquid cannot be compressed, the upper part of the gas piston is filled with sealing liquid, a gap of a sealing ring is filled, and gas leakage is reduced. According to the structure, lubricating and hydraulic media can be combined into a whole, hydraulic oil is stored through the crankcase and serves as the lubricating media, and the equipment size is further reduced in the mode that an oil pump is arranged inside. And meanwhile, a multi-stage compression form can be combined, so that the discharge pressure is further improved. The invention can be used for high-pressure hydrogen filling piston type compressors of gas stations and energy storage stations, and can also be used in the field of other high-pressure and ultrahigh-pressure gas compressors.

Description

Technical Field

[0001] The present invention belongs to the technical field of compressors, and in particular to a piston compressor driven by liquid pressure. Background Art

[0002] Hydrogen energy is regarded as the key to future energy transformation due to its clean and renewable characteristics. It is not only a clean energy that only produces water when burned and has no greenhouse gas emissions, which helps reduce dependence on fossil fuels and mitigate climate change, but also as an energy carrier, hydrogen can be stored and transported, solving the intermittent problem of renewable energy. At the same time, it has broad application potential in many fields such as transportation, industrial production, power generation and home heating, promoting economic development and creating jobs. High-pressure hydrogen compressors are crucial in hydrogen energy systems. By compressing hydrogen to a high-pressure state, it not only improves the storage and transportation efficiency of hydrogen energy, but also significantly improves the energy density, allowing more hydrogen energy to be stored in a limited space, adapting to various application scenarios such as hydrogen refueling stations for hydrogen fuel cell vehicles, industrial hydrogen supply, and hydrogen power generation. With the advancement of technology, the efficiency and reliability of high-pressure hydrogen compressors are constantly improving, which helps to reduce the overall cost of hydrogen energy systems and promote the widespread application of hydrogen energy.

[0003] Hydrogen compressors are mainly divided into two types: diaphragm type and liquid-driven type. Diaphragm compressors use flexible diaphragms to achieve gas compression. They are characterized by no pollution, low maintenance, high pressure ratio and small flow rate and high pressure ratio, but they are more expensive and slower. Liquid-driven compressors compress gas by driving pistons or plungers with liquid. They have the advantages of high efficiency, large flow, low vibration and high reliability, but they may require more maintenance and have a higher system complexity. The choice of compressor depends on application requirements, cost and maintenance capabilities.

[0004] Liquid-sealed compressors, represented by ionic liquid compressors, use almost incompressible liquids, such as ionic liquids, to replace the pistons in traditional compressors to achieve gas compression. The main advantages of ionic liquids include no saturated vapor pressure and extremely low gas solubility, which makes them have good sealing and lubricity under high pressure, while also effectively reducing energy loss. The working principle of ionic liquid compressors is based on the characteristics of ionic liquids. They produce volume changes in the cylinder as the liquid piston moves up and down, thereby compressing the gas. This type of compressor has many advantages over traditional piston compressors, such as solving the problem of sealing and lubrication under high pressure, having good adaptability to a wide range of working conditions and an efficient compression process, and is also suitable for designing large-displacement models.

[0005] However, most current ion liquid compressors use hydraulic pumps to increase the pressure of the hydraulic oil, which is connected to the gas compression part through a hydraulic pipeline. This brings several problems: 1) Since the hydraulic and gas compression parts are separated, the structure is not compact; 2) The hydraulic pipeline is too long, resulting in the hydraulic oil switching speed not being too fast, which hinders the speed increase. Summary of the invention

[0006] The purpose of the present invention is to overcome the problems caused by the separation of hydraulic and gas compression structures in traditional ionic liquid compressors, and to provide a piston compressor driven by liquid pressure, in which the hydraulic and gas compression devices are placed in a cylinder body and driven by a crank-connecting rod mechanism, thereby simplifying the structural complexity and control difficulty, and also facilitating multi-stage compression.

[0007] The purpose of the present invention is to be solved by the following technical solutions: The single-stage compressor includes a cylinder body, an intake valve, an exhaust valve, a gas piston, a gas piston upper seal, a gas piston lower seal, a liquid piston seal, a liquid piston, a piston rod, a relief valve, a liquid replenishment check valve and a waste liquid check valve.

[0008] The cylinder body and the lower surface of the gas piston form a compression chamber, in which a sealing liquid is placed, and the compression chamber is connected to an intake valve and an exhaust valve installed on the cylinder body; The cylinder body, the lower surface of the gas piston and the upper surface of the liquid piston form a hydraulic chamber, in which hydraulic oil is placed, and the hydraulic chamber is connected to the inlet of the overflow valve and the liquid replenishment check valve through a pipeline; The cylinder body and the gas piston form a balance chamber, and the balance chamber is connected to the inlet of the waste liquid one-way valve; The above-mentioned air inlet valve is connected to the external air inlet and the outlet of the liquid replenishment control valve through pipelines respectively, and the inlet of the liquid replenishment control valve is connected to the outlet of the sealed liquid storage tank; the above-mentioned exhaust valve is connected to the inlet of the gas-liquid separator component, the liquid outlet of the gas-liquid separator component is connected to the inlet of the sealed liquid storage tank, and the gas outlet of the gas-liquid separator component is connected to the next-stage compressor or gas-using component; The above waste liquid one-way valve outlet is connected to the waste liquid storage tank; The inlets of the overflow valve and the liquid replenishing one-way valve are connected to each other and then connected to the hydraulic oil storage tank through a pipeline.

[0009] Furthermore, the piston rod is mounted on a crankshaft, a first bearing and a second bearing are mounted on both sides of the crankshaft, and the crankshaft is driven by a prime mover; Furthermore, the crankcase is connected to the cylinder block, the crankshaft is placed in the crankcase, an oil pump is installed on the crankshaft, the oil pump inlet penetrates into the crankcase hydraulic oil at the bottom of the crankcase through a pipeline, the oil pump outlet is connected to the liquid replenishment one-way valve, and the overflow valve inlet is connected to the crankcase hydraulic oil inlet; Furthermore, by connecting multiple compressor stages in series, a multi-stage compressor unit can be formed; Furthermore, the prime mover may be any type of machinery that provides rotational power, such as an electric motor, a steam turbine, or a gas turbine; Furthermore, the gas piston upper seal, gas piston lower seal, and liquid piston seal are composed of one ring or multiple rings; Furthermore, the gas piston upper seal, gas piston lower seal, and liquid piston seal are made of metal, non-metal, or a combination or composite of the two; Furthermore, the sealing liquid is aqueous or oily and has extremely low solubility in the compressed gas; Beneficial effects of the present invention: The hydraulic and gas compression devices are placed in a cylinder block and driven by a crank-connecting rod mechanism, thereby simplifying the structural complexity and control difficulty and making it easy to achieve multi-stage compression. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Schematic diagram of a piston compressor driven by liquid pressure in Example 1 Figure 2 Schematic diagram of Example 2 Figure 3 Schematic diagram of a multi-stage piston compressor driven by liquid pressure in Example 3 Description of the numbers in the figure: 1-cylinder body; 2-intake valve; 3-exhaust valve; 4-gas piston; 5-gas piston upper seal; 6-gas piston lower seal; 7-liquid piston seal; 8-liquid piston; 9-piston rod; 10-prime mover; 11-first bearing; 12-second bearing; 13-crankshaft; 14-crankcase; 15-oil pump; 16-hydraulic oil buffer tank; 101-liquid replenishment control valve; 102-sealed liquid storage tank; 103-gas-liquid separator assembly; 104-waste liquid storage tank; 105-waste liquid check valve; 106-overflow valve; 107-liquid replenishment check valve; 108-hydraulic oil storage tank; 201-compression chamber; 202-balance chamber; 203-sealing liquid; 204-hydraulic oil; 204A-crankcase hydraulic oil; 205-hydraulic chamber; 1001 - first stage compressor; 1002 - second stage compressor; 1003 - third stage compressor; 1004 - fourth stage compressor. DETAILED DESCRIPTION

[0011] The structural features and technical implementation process of the present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0012] 1) Example 1 Figure 1 It is a piston compressor driven by liquid pressure. Each stage of the compressor includes a cylinder 1, an intake valve 2, an exhaust valve 3, a gas piston 4, a gas piston upper seal 5, a gas piston lower seal 6, a liquid piston seal 7, a liquid piston 8, a piston rod 9, a relief valve 106, a liquid replenishment check valve 107 and a waste liquid check valve 105; The cylinder body 1 and the lower surface of the gas piston 4 form a compression chamber 201, in which a sealing liquid 203 is placed, and the compression chamber 201 is connected to the intake valve 2 and the exhaust valve 3 installed on the cylinder body 1; The cylinder body 1, the lower surface of the gas piston 4 and the upper surface of the liquid piston 8 form a hydraulic chamber 205, in which hydraulic oil 204 is placed, and the hydraulic chamber 205 is connected to the inlet of the overflow valve 106 and the liquid replenishment check valve 107 through a pipeline; The cylinder body 1 and the gas piston 4 form a balance chamber 202, and the balance chamber 202 is connected to the inlet of the waste liquid check valve 105; The air inlet valve 2 is connected to the external air inlet and the outlet of the liquid replenishment control valve 101 through pipelines, and the inlet of the liquid replenishment control valve 101 is connected to the outlet of the sealed liquid storage tank 102; the exhaust valve 3 is connected to the inlet of the gas-liquid separator component 103, the liquid outlet of the gas-liquid separator component 103 is connected to the inlet of the sealed liquid storage tank 102, and the gas outlet of the gas-liquid separator component 103 is connected to the next stage compressor or gas-using component; The outlet of the waste liquid one-way valve 105 is connected to the waste liquid storage tank 104; The inlets of the overflow valve 106 and the liquid replenishment check valve 107 are connected to each other and then connected to the hydraulic oil storage tank 108 through a pipeline; The piston rod 9 is mounted on a crankshaft 13, a first bearing 11 and a second bearing 12 are mounted on both sides of the crankshaft 13, and the crankshaft is driven by a prime mover 10; The prime mover is an AC motor; The gas piston upper seal 5, the gas piston lower seal 6, and the liquid piston seal 7 are composed of two support rings and a non-metallic polytetrafluoroethylene ring; The sealing liquid 203 is an ionic liquid; After the crankshaft 14 rotates, it drives the piston rod 9 to move, and then drives the liquid piston 8 to reciprocate. When the liquid piston 8 moves to the upper dead center, the volume of the hydraulic chamber 205 tends to decrease, and the hydraulic oil 204 is compressed. Since the compressibility of the hydraulic oil 204 is very low, it will push the gas piston 9 to move to the upper dead center, so that the gas in the compression chamber 201 is compressed until it reaches a certain pressure and is discharged from the exhaust valve 3 until the liquid piston 8 reaches the upper dead center, completing the compression and exhaust process; when the liquid piston 8 moves to the lower dead center, the volume of the hydraulic chamber 205 tends to increase, and the hydraulic oil 204 is expanded. Similarly, since the compressibility of the hydraulic oil 204 is very low, the pressure in the hydraulic chamber 205 decreases. Under the action of the gas pressure in the compression chamber 201, the gas piston 4 will move downward, and fresh gas will be sucked into the cylinder body 1 through the intake valve 2 until the liquid piston 8 reaches the lower dead center, completing the expansion and intake process; The pressure in the sealing liquid storage tank 102 is greater than the suction pressure, so the liquid replenishment control valve 101 is opened to inject sealing liquid 203 into the compression chamber 201 through the intake valve 2, and the sealing liquid 203 flows into the upper part of the gas piston 4, so that the compressed medium cannot leak through the seal 5 on the gas piston. At the same time, during the exhaust process, part of the sealing liquid 203 is discharged from the exhaust valve 3 along with the gas, and the discharged gas-liquid mixture is separated by the gas-liquid separator assembly 103, and the separated sealing liquid flows into the sealing liquid storage tank 102.

[0013] When the liquid piston 8 approaches the upper dead center and the amount of sealing liquid 203 in the compression chamber 201 is excessive, the overflow valve 106 is opened to discharge part of the hydraulic oil 204. When the liquid piston 8 approaches the lower dead center and the amount of sealing liquid 203 in the compression chamber 201 is too little, the hydraulic oil 204 is replenished through the liquid replenishment one-way valve 107.

[0014] A small amount of leaked hydraulic oil and sealing liquid are collected in the balance chamber 202 and eventually discharged into the waste liquid storage tank 104 through the waste liquid one-way valve 105 .

[0015] 2) Example 2 Figure 2 It is a schematic diagram of Example 2. Compared with Example 1, the inlet and outlet of the overflow valve 106 and the liquid replenishment check valve 107 are no longer connected to each other in terms of the process; an oil pump 15 is installed on one side of the crankshaft 13. When the crankshaft 13 rotates, the oil pump 15 is driven to rotate, and the crankcase hydraulic oil 204A is sucked in from the bottom of the crankcase 14 and pumped to the hydraulic oil buffer tank 16. The hydraulic oil buffer tank 16 is connected to the inlet of the liquid replenishment check valve 107; the hydraulic chamber 205 is directly connected to the inlet of the overflow valve 106, and the outlet of the overflow valve 106 is connected to the crankcase 14, and the overflowing hydraulic oil 204 directly flows into the crankcase 14.

[0016] In principle, in Example 2, the lubricating oil and the hydraulic oil are combined into one, and no oil pump or other hydraulic pump is placed on the outside. The hydraulic chamber 205 is replenished with fluid through the oil pump 15 built into the crankcase 14. At the same time, the overflowing hydraulic oil 204 is also used as lubricating oil to directly lubricate each friction pair, further simplifying the structure.

[0017] 2) Example 3 Figure 3 Schematic diagram of Example 3. Example 3 is a form of Example 1 expanded from a single stage to a multi-stage form. In this embodiment, a 4-stage compressor is constructed, namely, a first-stage compressor 1001, a second-stage compressor 1002, a third-stage compressor 1003 and a fourth-stage compressor 1004. The composition of each stage compressor is the same as that of Example 1. The crankshaft 13 is a multi-crank form, and the piston rods of all stages of the compressors are installed on the crankshaft 13. The inlets of the overflow valves and the liquid replenishment check valves of all stages are connected together and then connected to the hydraulic oil storage tank 108; The exhaust valve outlet of the first-stage compressor 1001 is connected to the intake valve inlet of the second-stage compressor 1002, the exhaust valve outlet of the second-stage compressor 1002 is connected to the intake valve inlet of the third-stage compressor 1003, the exhaust valve outlet of the third-stage compressor 1003 is connected to the intake valve inlet of the fourth-stage compressor 1004, and the exhaust valve outlet of the fourth-stage compressor 1004 is connected to the gas-liquid separator assembly 103.

[0018] The pressure ratio that can be increased by single-stage compression is certain, but through multi-stage compression, the final exhaust pressure can be increased to a higher value to meet user needs.

[0019] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A piston compressor driven by liquid pressure, characterized in that: A multi-stage compressor unit comprising a single-stage compressor or a plurality of stage compressors connected in series, wherein each stage compressor comprises a cylinder body (1) and a crankcase (14), a gas piston (4) and a liquid piston (8) are arranged in the cylinder body (1) from top to bottom, and the liquid piston (8) is connected to the crankcase (14) via a piston rod (9); The cylinder body (1) and the upper surface of the gas piston (4) form a compression chamber (201), a sealing liquid (203) is placed in the compression chamber (201), and the compression chamber (201) is connected to an intake valve (2) and an exhaust valve (3) installed on the cylinder body (1); The air inlet valve (2) is connected to an external air inlet and an outlet of a liquid replenishment control valve (101) through pipelines respectively, and the inlet of the liquid replenishment control valve (101) is connected to the outlet of a sealed liquid storage tank (102); the air exhaust valve (3) is connected to an inlet of a gas-liquid separator component (103), the liquid outlet of the gas-liquid separator component (103) is connected to an inlet of the sealed liquid storage tank (102), and the gas outlet of the gas-liquid separator component (103) is connected to a compressor of a next stage or a gas-using component; A balance chamber (202) is formed between the cylinder body (1) and the side wall of the gas piston (4); the balance chamber (202) is connected to the inlet of the waste liquid one-way valve (105); and the outlet of the waste liquid one-way valve (105) is connected to the waste liquid storage tank (104); The cylinder body (1), the lower surface of the gas piston (4) and the upper surface of the liquid piston (8) form a hydraulic chamber (205), in which hydraulic oil (204) is placed, and the hydraulic chamber (205) is connected to the inlet of the overflow valve (106) and the liquid replenishment check valve (107) through a pipeline.

2. A piston compressor driven by liquid pressure according to claim 1, characterized in that: The inlets of the overflow valve (106) and the liquid replenishment check valve (107) are connected to each other and then connected to the hydraulic oil storage tank (108) through a pipeline.

3. A piston compressor driven by liquid pressure according to claim 1, characterized in that: The crankcase (14) comprises: a crankshaft (13) placed in the crankcase (14) and a prime mover (10) driving the crankshaft (13) to work; the crankshaft (13) is connected to a piston rod (9); and a first bearing (11) and a second bearing (12) are installed on both sides of the crankshaft (13).

4. A piston compressor driven by liquid pressure according to claim 3, characterized in that: The bottom of the crankcase (14) is provided with a crankcase hydraulic oil (204A) and a crankcase hydraulic oil inlet. The crankshaft (13) is mounted with an oil pump (15). The inlet of the oil pump (15) penetrates into the crankcase hydraulic oil (204A) at the bottom of the crankcase (14) through a pipeline. The outlet of the oil pump (15) is connected to the liquid replenishing one-way valve (107). The inlet of the overflow valve (106) is connected to the crankcase hydraulic oil inlet.

5. A piston compressor driven by liquid pressure according to claim 1, characterized in that: The cylinder body (1) further comprises: a gas piston upper seal (5) arranged between the upper part of the gas piston (4) and the inner wall of the cylinder body (1), a gas piston lower seal (6) arranged between the lower part of the gas piston (4) and the inner wall of the cylinder body (1), and a liquid piston seal (7) arranged between the liquid piston (8) and the inner wall of the cylinder body (1).

6. A piston compressor driven by liquid pressure according to claim 5, characterized in that: The gas piston upper seal (5), the gas piston lower seal (6), and the liquid piston seal (7) are composed of one ring or multiple rings.

7. A piston compressor driven by liquid pressure according to any one of claims 5 or 6, characterized in that: The gas piston upper seal (5), the gas piston lower seal (6), and the liquid piston seal (7) are made of metal, non-metal, or a combination or composite of the two.

8. A piston compressor driven by liquid pressure according to claim 1, characterized in that: The prime mover is a machine that provides rotational power, including but not limited to electric motors, steam turbines, and gas turbines.

9. A piston compressor driven by liquid pressure according to claim 1, characterized in that: The sealing liquid (203) is an aqueous or oily solvent having extremely low solubility in the compressed gas.

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