A piston compressor driven by liquid pressure

Abstract

The application discloses a piston compressor driven by liquid pressure, which integrates hydraulic and gas compression components in one cylinder, drives a hydraulic piston by rotation of a crankshaft, and then drives a gas piston by using the incompressible characteristics of liquid, fills the upper part of the gas piston with sealing liquid, fills the gap between sealing rings, and reduces gas leakage. The structure can also combine lubrication and hydraulic medium, store hydraulic oil in the crankcase, use the hydraulic oil as lubricating medium, and further reduce the size of the equipment by adopting an oil pump built-in mode. Meanwhile, the piston compressor can be combined into a multi-stage compression form to further improve the discharge pressure. The piston compressor can be used for high-pressure hydrogen filling piston compressors of gas stations and energy storage stations, and can also be used in other high-pressure and super-high-pressure gas compressor fields.

Description

Technical Field

[0001] This invention application belongs to the field of compressor technology, and in particular relates to a reciprocating compressor driven by liquid pressure. Background Technology

[0002] Hydrogen energy, due to its clean and renewable characteristics, is considered key to the future energy transition. It is not only a clean energy source, producing only water when burned and emitting no greenhouse gases, thus helping to reduce dependence on fossil fuels and mitigate climate change, but also, as an energy carrier, it can be stored and transported, addressing the intermittency of renewable energy sources. Furthermore, it has broad application potential in multiple fields such as transportation, industrial production, power generation, and residential heating, driving economic development and creating jobs. High-pressure hydrogen compressors are crucial in hydrogen energy systems. By compressing hydrogen to a high-pressure state, they not only improve the efficiency of hydrogen storage and transportation but also significantly increase energy density, enabling the storage of more hydrogen in a limited space. This adapts to various application scenarios, including hydrogen refueling stations for fuel cell vehicles, industrial hydrogen supply, and hydrogen power generation. With technological advancements, the efficiency and reliability of high-pressure hydrogen compressors are continuously improving, helping to reduce the overall cost of hydrogen energy systems and promoting the widespread application of hydrogen energy.

[0003] Hydrogen compressors are mainly divided into two types: diaphragm compressors and liquid-driven compressors. Diaphragm compressors use flexible diaphragms to compress gas, featuring zero pollution, low maintenance, high pressure ratio, and low flow rate with high pressure ratio, but they are more expensive and slower. Liquid-driven compressors, on the other hand, use liquid to drive pistons or plungers to compress gas, offering advantages such as high efficiency, high flow rate, low vibration, and high reliability, but they may require more maintenance and have higher system complexity. The choice of compressor depends on application requirements, cost, and maintenance capabilities.

[0004] Liquid-sealed compressors, exemplified by ionic liquid compressors, use virtually incompressible liquids, such as ionic liquids, to replace the pistons in traditional compressors, thereby compressing gases. The main advantages of ionic liquids include no saturated vapor pressure and extremely low gas solubility, which gives them excellent sealing and lubrication properties under high pressure, while also effectively reducing energy consumption. The working principle of ionic liquid compressors is based on the properties of ionic liquids; they create volume changes within the cylinder as the liquid piston moves up and down, thus compressing the gas. Compared to traditional piston compressors, this type of compressor has many advantages, such as solving the problems of sealing and lubrication under high pressure, having good adaptability to a wide range of operating conditions, a highly efficient compression process, and being suitable for designing large-displacement models.

[0005] However, most current ion liquid compressors use hydraulic pumps to increase the pressure of hydraulic oil, which is then connected to the gas compression section via hydraulic pipelines. This leads to several problems: 1) Since the hydraulic and gas compression sections are separate, the structure is not compact; 2) The hydraulic pipelines are too long, which prevents the hydraulic oil from switching too quickly, hindering the increase in rotational speed. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems caused by the separate hydraulic and gas compression structures in traditional ionic liquid compressors, and to provide a piston compressor driven by liquid pressure, which places the hydraulic and gas compression devices in a single cylinder and drives the device through a crank-connecting rod mechanism, thereby simplifying the structural complexity and control difficulty, and also making it easy to achieve multi-stage compression.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A single-stage compressor includes a cylinder block, an intake valve, an exhaust valve, a gas piston, an upper gas piston seal, a lower gas piston seal, a liquid piston seal, a liquid piston, a piston rod, an overflow valve, a replenishing check valve, and a waste liquid check valve.

[0009] The cylinder body and the lower surface of the gas piston form a compression chamber, which contains a sealing liquid. The compression chamber is connected to the intake valve and exhaust valve installed on the cylinder body.

[0010] The cylinder block, the lower surface of the gas piston and the upper surface of the liquid piston form a hydraulic chamber. Hydraulic oil is placed in the hydraulic chamber. The hydraulic chamber is connected to the inlet of the overflow valve and the replenishment check valve through a pipeline.

[0011] The aforementioned cylinder and gas piston form a balance chamber, which is connected to the inlet of the waste liquid check valve;

[0012] The aforementioned intake valves are connected to the external intake and liquid replenishment control valve outlets via pipelines, respectively; the liquid replenishment control valve inlet is connected to the sealed liquid storage tank outlet; the aforementioned exhaust valve is connected to the gas-liquid separator assembly inlet; the gas-liquid separator assembly liquid outlet is connected to the sealed liquid storage tank inlet; and the gas-liquid separator assembly gas outlet is connected to the next stage compressor or gas-consuming component.

[0013] The outlet of the aforementioned waste liquid check valve is connected to the waste liquid storage tank;

[0014] The above-mentioned overflow valve and replenishment check valve inlet are interconnected and then connected to the hydraulic oil storage tank through pipelines.

[0015] Furthermore, the piston rod is mounted on the crankshaft, and a first bearing and a second bearing are mounted on both sides of the crankshaft, which is driven by a prime mover;

[0016] Furthermore, the crankcase is connected to the cylinder block, the crankshaft is placed inside the crankcase, an oil pump is installed on the crankshaft, the oil pump inlet is inserted into the crankcase hydraulic oil at the bottom of the crankcase through a pipe, the oil pump outlet is connected to the replenishing check valve, and the overflow valve inlet is connected to the crankcase hydraulic oil inlet.

[0017] Furthermore, by connecting multiple compressor stages in series, a multi-stage compressor unit can be formed;

[0018] Furthermore, the aforementioned prime mover can be any type of machinery that provides rotational power, such as an electric motor, a steam turbine, or a gas turbine.

[0019] Furthermore, the gas piston upper seal, gas piston lower seal, and liquid piston seal mentioned above are composed of one or more rings;

[0020] 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 both.

[0021] Furthermore, the aforementioned sealing liquid is water- or oil-based and has extremely low solubility for the compressed gas.

[0022] The beneficial effects of this invention are:

[0023] By placing the hydraulic and gas compression devices in a single cylinder and driving the device through a crank-connecting rod mechanism, the structural complexity and control difficulty are simplified, and multi-stage compression is also easily achieved. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a reciprocating compressor driven by liquid pressure, as shown in Example 1.

[0025] Figure 2 This is a schematic diagram of Example 2.

[0026] Figure 3 This is a schematic diagram of a multi-stage reciprocating compressor driven by liquid pressure, as described in Example 3.

[0027] Explanation of the labels in the diagram:

[0028] 1-Cylinder block; 2-Intake valve; 3-Exhaust valve; 4-Gas piston; 5-Upper seal of gas piston; 6-Lower seal of gas piston; 7-Liquid piston seal; 8-Liquid piston; 9-Piston rod; 10-Prime mover; 11-First bearing; 12-Second bearing; 13-Crankshaft; 14-Crankshaft case; 15-Oil pump; 16-Hydraulic oil buffer tank;

[0029] 101-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-Replenishment check valve; 108-Hydraulic oil storage tank;

[0030] 201 - Compression chamber; 202 - Balance chamber; 203 - Sealing fluid; 204 - Hydraulic oil; 204A - Crankcase hydraulic oil; 205 - Hydraulic chamber;

[0031] 1001 - First stage compressor; 1002 - Second stage compressor; 1003 - Third stage compressor; 1004 - Fourth stage compressor. Detailed Implementation

[0032] The structural features and technical implementation process of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0033] 1) Example 1

[0034] Figure 1 It is a reciprocating 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, an upper gas piston seal 5, a lower gas piston seal 6, a liquid piston seal 7, a liquid piston 8, a piston rod 9, an overflow valve 106, a replenishing check valve 107, and a waste liquid check valve 105.

[0035] The cylinder 1 and the lower surface of the gas piston 4 form a compression chamber 201, in which a sealing liquid 203 is placed. The compression chamber 201 is connected to the intake valve 2 and the exhaust valve 3 installed on the cylinder 1.

[0036] The cylinder 1, the lower surface of the gas piston 4 and the upper surface of the liquid piston 8 form a hydraulic chamber 205. Hydraulic oil 204 is placed in the hydraulic chamber 205. The hydraulic chamber 205 is connected to the overflow valve 106 and the inlet of the replenishing check valve 107 through a pipeline.

[0037] The cylinder 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.

[0038] The intake valve 2 is connected to the external intake and liquid replenishment control valve 101 outlet through pipelines, and the liquid replenishment control valve 101 inlet 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 assembly 103, the liquid outlet of the gas-liquid separator assembly 103 is connected to the inlet of the sealed liquid storage tank 102, and the gas outlet of the gas-liquid separator assembly 103 is connected to the next stage compressor or gas-consuming component.

[0039] The outlet of the waste liquid check valve 105 is connected to the waste liquid storage tank 104;

[0040] The overflow valve 106 and the replenishment check valve 107 are interconnected and then connected to the hydraulic oil storage tank 108 via a pipeline.

[0041] The piston rod 9 is mounted on the crankshaft 13. A first bearing 11 and a second bearing 12 are mounted on both sides of the crankshaft 13. The crankshaft is driven by the prime mover 10.

[0042] The prime mover is an AC electric motor;

[0043] The upper gas piston seal 5, the lower gas piston seal 6, and the liquid piston seal 7 are composed of two support rings and a non-metallic polytetrafluoroethylene ring.

[0044] The sealing liquid 203 is an ionic liquid;

[0045] After the crankshaft 14 rotates, it drives the piston rod 9 to move, which in turn 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 hydraulic oil 204 has very low compressibility, 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 a certain pressure is reached, and then 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. Again, since the hydraulic oil 204 has very low compressibility, 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 drawn into the cylinder 1 through the intake valve 2, until the liquid piston 8 reaches the lower dead center, completing the expansion and intake process.

[0046] The pressure in the sealed liquid storage tank 102 is greater than the suction pressure, so the liquid replenishment control valve 101 is opened to inject the sealing liquid 203 into the compression chamber 201 through the air inlet valve 2. The sealing liquid 203 flows into the upper part of the gas piston 4, preventing the compressed medium from leaking through the seal 5 on the gas piston. At the same time, during the exhaust process, some of the sealing liquid 203 is discharged from the exhaust valve 3 along with the gas. The discharged gas-liquid mixture is separated by the gas-liquid separator assembly 103, and the separated sealing liquid flows into the sealed liquid storage tank 102.

[0047] When the liquid piston 8 approaches the top dead center and the amount of sealing liquid 203 in the compression chamber 201 is too large, the overflow valve 106 is opened to discharge some of the hydraulic oil 204. When the liquid piston 8 approaches the bottom dead center and the amount of sealing liquid 203 in the compression chamber 201 is too small, the hydraulic oil 204 is replenished through the replenishment check valve 107.

[0048] A small amount of leaked hydraulic oil and sealing fluid is collected in the balance chamber 202 and eventually discharged into the waste liquid storage tank 104 through the waste liquid check valve 105.

[0049] 2) Example 2

[0050] Figure 2 This is a schematic diagram of Embodiment 2. Compared with Embodiment 1, the overflow valve 106 and the inlet and outlet of the replenishing check valve 107 are no longer connected to each other in terms of process. An oil pump 15 is installed on one side of the crankshaft 13. When the crankshaft 13 rotates, it drives the oil pump 15 to rotate, drawing crankcase hydraulic oil 204A from the bottom of the crankcase 14 and pumping it to the hydraulic oil buffer tank 16. The hydraulic oil buffer tank 16 is connected to the inlet of the replenishing 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. The overflowing hydraulic oil 204 flows directly into the crankcase 14.

[0051] In principle, in Example 2, the lubricating oil and hydraulic oil are combined into one, and there is no longer an oil pump or other hydraulic pump placed on the outside. The hydraulic chamber 205 is replenished by the oil pump 15 built into the crankcase 14. At the same time, the overflowed hydraulic oil 204 also serves as lubricating oil to directly lubricate each friction pair, further simplifying the structure.

[0052] 2) Example 3

[0053] Figure 3 This is a schematic diagram of Embodiment 3, which is an extension of Embodiment 1 from a single stage to a multi-stage form. In this embodiment, a four-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 Embodiment 1. The crankshaft 13 is of the multi-crank type, and the piston rods of all stages of the compressor are mounted on the crankshaft 13. The overflow valves and replenishment check valve inlets of all stages are connected together and then connected to the hydraulic oil storage tank 108.

[0054] The outlet of the exhaust valve of the first-stage compressor 1001 is connected to the inlet of the suction valve of the second-stage compressor 1002. The outlet of the exhaust valve of the second-stage compressor 1002 is connected to the inlet of the suction valve of the third-stage compressor 1003. The outlet of the exhaust valve of the third-stage compressor 1003 is connected to the inlet of the suction valve of the fourth-stage compressor 1004. The outlet of the exhaust valve of the fourth-stage compressor 1004 is connected to the gas-liquid separator assembly 103.

[0055] A single-stage compression can only increase the pressure ratio to a certain extent, while through multi-stage compression, the final exhaust pressure can be increased to a higher value to meet user needs.

[0056] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A reciprocating compressor driven by liquid pressure, characterized in that... The compressor unit includes a single-stage compressor or a multi-stage compressor unit formed by connecting multiple stages of compressors in series. Each stage of compressor includes a cylinder block (1) and a crankcase (14). A gas piston (4) and a liquid piston (8) are arranged from top to bottom inside the cylinder block (1). The liquid piston (8) is connected to the crankcase (14) through a piston rod (9). The cylinder (1) and the upper surface of the gas piston (4) form a compression chamber (201), in which a sealing liquid (203) is placed. The compression chamber (201) is connected to the intake valve (2) and the exhaust valve (3) installed on the cylinder (1). The intake valve (2) is connected to the outlet of the external intake and liquid replenishment control valve (101) via 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 assembly (103), the liquid outlet of the gas-liquid separator assembly (103) is connected to the inlet of the sealed liquid storage tank (102), and the gas outlet of the gas-liquid separator assembly (103) is connected to the next stage compressor or gas-consuming component; A balance chamber (202) is formed between the cylinder (1) and the side wall of the gas piston (4). The balance chamber (202) is connected to the inlet of the waste liquid check valve (105), and the outlet of the waste liquid check valve (105) is connected to the waste liquid storage tank (104). A hydraulic chamber (205) is formed between the lower surface of the cylinder (1) and the gas piston (4) and the upper surface of the liquid piston (8). Hydraulic oil (204) is placed in the hydraulic chamber (205). The hydraulic chamber (205) is connected to the inlet of the overflow valve (106) and the replenishment check valve (107) through a pipe. The bottom of the crankcase (14) is provided with crankcase hydraulic oil (204A) and crankcase hydraulic oil inlet. An oil pump (15) is installed on the crankshaft (13). The inlet of the oil pump (15) extends into the crankcase hydraulic oil (204A) at the bottom of the crankcase (14) through a pipe. The outlet of the oil pump (15) is connected to the replenishing check valve (107). The inlet of the overflow valve (106) is connected to the crankcase hydraulic oil inlet. When the liquid piston (8) approaches the top dead center and the amount of sealing liquid (203) in the compression chamber (201) is too large, the overflow valve (106) is opened to discharge some of the hydraulic oil (204). When the liquid piston (8) approaches the bottom dead center and the amount of sealing liquid (203) in the compression chamber (201) is too small, the hydraulic oil (204) is replenished through the replenishment check valve (107).

2. A reciprocating compressor driven by liquid pressure according to claim 1, characterized in that, The overflow valve (106) and the replenishment check valve (107) are interconnected at their inlets and then connected to the hydraulic oil storage tank (108) via pipelines.

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

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

5. A reciprocating compressor driven by liquid pressure according to claim 4, characterized in that, The upper gas piston seal (5), the lower gas piston seal (6), and the liquid piston seal (7) are composed of one or more rings.

6. The reciprocating compressor driven by liquid pressure according to any one of claims 4 or 5, characterized in that, The gas piston upper seal (5), gas piston lower seal (6), and liquid piston seal (7) are made of metal, non-metal, or a combination or composite of both.

7. A reciprocating compressor driven by liquid pressure according to claim 3, 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.

8. A reciprocating compressor driven by liquid pressure according to claim 1, characterized in that, The sealing liquid (203) is an aqueous or oily solution with extremely low solubility for the compressed gas.

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