Multistage compression piston group opposed structure and compressor

Abstract

The invention relates to the technical field of mechanical compression, and provides a multi-stage compression piston set opposed structure and a compressor. The structure comprises a crankcase, a crankshaft connecting rod positioning structure, a two-stage and three-stage piston and air cylinder assembly and a first-stage and four-stage piston and air cylinder assembly, the piston sets on the two sides of the crankcase move in a synchronous and reverse mode, and first-order reciprocating inertia force generated by the piston sets is equal in magnitude and opposite in direction, so that the first-order reciprocating inertia force counteracts on the central axis of the crankshaft, vibration and noise of the whole machine are remarkably reduced, the whole structure of the machine is more compact, and the occupied area is remarkably reduced. The four-stage compression can more finely control the compression process, effectively manage heat and reduce the operation load of key parts, so that higher compression efficiency and longer service life of the parts are realized, and the four-stage compression compressor is finally suitable for application scenes with higher requirements on high pressure and high reliability.

Description

Technical Field

[0001] The present application relates to the field of mechanical compression technology, and in particular to a multi-stage compression piston group opposed structure and a compressor. Background Art

[0002] In the field of mechanical engineering, compressor technology has always been an indispensable key technology in industrial production and daily life. With the continuous development of industry, the requirements for compressor performance, efficiency, and environmental friendliness are also increasing. High-performance compressors can provide stable and reliable power support for numerous industries such as chemical, pharmaceutical, and food processing, driving their rapid development and occupying a vital position in the modern industrial system. At the same time, with the increasing awareness of environmental protection, higher requirements are also being placed on the environmental performance of compressors, which is driving the continuous development of compressor technology towards more environmentally friendly and energy-saving directions.

[0003] Traditional multi-stage compressors often employ an asymmetrical or vertical arrangement of piston groups. This layout makes it difficult to effectively offset the inertial forces of the piston groups during operation, resulting in high vibration and noise. Furthermore, during compression, traditional compressors experience high exhaust temperatures per stage, which is detrimental to the long-term life of the piston rings. Furthermore, the pressure ratio distribution between stages is not optimal, impacting overall compression efficiency.

[0004] In response to the defects existing in the above-mentioned related technologies, the present application aims to provide a new type of multi-stage compression piston group opposed structure and compressor to solve the problems of traditional compressors such as large vibration, high noise, unreasonable pressure ratio distribution between stages, and reliance on oil medium for lubrication. Summary of the Invention

[0005] In order to solve the problems of large vibration, high noise, unreasonable pressure ratio distribution between stages and reliance on oil medium for lubrication in traditional compressors, the present application provides a multi-stage compression piston group opposed structure and a compressor.

[0006] On the one hand, the present application provides a multi-stage compression piston group opposed structure, which adopts the following technical solutions: A crankcase, wherein a crankshaft connecting rod positioning structure is provided in the crankcase; A second- and third-stage piston and cylinder assembly is provided on a first side of the crankcase, the second- and third-stage piston and cylinder assembly comprising a second- and third-stage connecting rod, a second- and third-stage integrated piston, a second-stage cylinder body, and a third-stage cylinder body connected in series with the second-stage cylinder body; a first end of the second- and third-stage connecting rod is connected to a first side of the crankshaft connecting rod positioning structure, the second- and third-stage integrated piston is connected to a second end of the second- and third-stage connecting rod, the second- and third-stage integrated piston having a second portion and a third portion, the second portion of the second- and third-stage integrated piston cooperates with the second-stage cylinder body to perform second-stage compression, and the third portion of the second- and third-stage integrated piston cooperates with the third-stage cylinder body to perform third-stage compression; A four-stage piston and cylinder assembly is arranged on the second side of the crankcase. The four-stage piston and cylinder assembly and the second and third stage piston and cylinder assemblies are symmetrically arranged relative to the crankshaft connecting rod positioning structure. The four-stage piston and cylinder assembly includes a four-stage connecting rod, a first double-acting piston, a first cylinder body and a four-stage cylinder body connected in series with the first cylinder body. The first end of the four-stage connecting rod is connected to the second side of the crankshaft connecting rod positioning structure, the second end of the four-stage connecting rod is constructed as a four-stage piston, the first double-acting piston is arranged on the four-stage connecting rod, the first double-acting piston cooperates with the first cylinder body to perform the first stage compression, and the four-stage piston cooperates with the four-stage cylinder body to perform the fourth stage compression.

[0007] This technical solution employs symmetrical, horizontally opposed arrangements of the second- and third-stage piston-cylinder assemblies and the first- and fourth-stage piston-cylinder assemblies on opposite sides of the crankcase. The piston groups are driven in opposite directions by a double-throw crankshaft, ensuring equal and opposite first-order reciprocating inertial forces. This effectively cancels out the inertial forces on the crankshaft's central axis, significantly reducing overall compressor vibration (to ≤16mm / s) and noise (to ≤88dBA) during operation, improving operational stability and operating comfort. Furthermore, this symmetrical, horizontally opposed layout results in a lower center of gravity and a flatter, more compact structure (reducing footprint by 40%), making it easier to install and layout, particularly in space-constrained applications. Furthermore, this structure achieves four-stage compression, ensuring a balanced distribution of pressure ratios across each stage, improving compression efficiency and lowering exhaust temperatures. This allows for more precise control of the compression process, effectively managing heat, and reducing the operating load on key components, resulting in higher compression efficiency and longer component life. This makes it suitable for applications requiring high pressure and reliability.

[0008] Optionally, a secondary piston ring and a secondary support ring are provided on the secondary part of the two- or three-stage integrated piston, a third piston ring and a third support ring are provided on the third part of the two- or three-stage integrated piston, a first piston ring and a first support ring are provided on the first double-acting piston, and a fourth piston ring and a fourth support ring are provided on the fourth piston.

[0009] By adopting the above technical solution, piston rings and support rings are arranged on each level of pistons / piston heads, thereby ensuring effective sealing of the cylinders of each compression stage, suppressing leakage of compressed gas from the high-pressure side to the low-pressure side, thereby ensuring compression efficiency; at the same time, the support ring is used to support the radial position of the piston in the cylinder, suppressing direct contact wear between the piston and the inner wall of the cylinder, and extending the service life of the components.

[0010] Optionally, the materials of the secondary piston ring, the tertiary piston ring, the primary piston ring and the fourth piston ring are self-lubricating materials.

[0011] By adopting the above technical solution and using self-lubricating materials (such as PTFE composite materials) to make piston rings at all levels, the piston rings themselves can provide lubrication and can run smoothly in the cylinder without the need for external lubricating oil, thereby achieving oil-free compression of compressed gas, avoiding the risk of oil contamination, and meeting industrial applications with high requirements for gas cleanliness and environmental protection requirements.

[0012] Optionally, a first isolation chamber is provided between the secondary cylinder block and the crankcase, and a second isolation chamber is provided between the primary cylinder block and the crankcase.

[0013] By adopting the above technical solution, an isolation chamber is set between the crankcase and the cylinder blocks of each initial compression stage, which preliminarily isolates the area of ​​the crankcase moving parts that require oil lubrication and the compression area that requires oil-free, creating conditions for achieving oil-free compression of the entire machine and helping to prevent the lubricating oil in the crankcase from entering the compression chamber.

[0014] Optionally, an oil scraper ring assembly is provided inside the first isolation chamber and the second isolation chamber, and the oil scraper ring assembly is used to scrape off the lubricating oil from the crankcase attached to the second and third connecting rods and the first and fourth connecting rods.

[0015] By adopting the above technical solution, by arranging an oil scraper ring assembly in the isolation chamber, the lubricating oil from the crankcase that may be attached to the reciprocating connecting rod can be effectively scraped off, further preventing the lubricating oil from entering the subsequent stuffing box sealing area and compression chamber, thereby ensuring the oil-free cleanliness of the compressed gas and improving the reliability of oil-free operation.

[0016] Optionally, a first stuffing box seal is provided in the secondary cylinder body, and the second and third stage connecting rods pass through the first isolation chamber and the first stuffing box seal and extend into the secondary cylinder body; a second stuffing box seal is provided in the primary cylinder body, and the fourth stage connecting rod passes through the second isolation chamber and the second stuffing box seal and extends into the primary cylinder body.

[0017] By adopting the above technical solution, a stuffing box seal is set at the entrance of the connecting rod into the cylinder block of each initial compression stage, which provides a key dynamic seal between the lubricating oil and the compressed gas, effectively suppressing the leakage of gas or liquid between the cylinder block and the crankcase, ensuring that the compressed gas will not be contaminated by the lubricating oil in the crankcase. It is one of the key measures to achieve oil-free compression.

[0018] Optionally, the secondary cylinder body is provided with a secondary air intake port, a secondary exhaust port, a secondary air intake valve provided at the secondary air intake port, and a secondary exhaust valve provided at the secondary exhaust port; the primary cylinder body is provided with a primary air intake port, a primary exhaust port, a primary air intake valve provided at the primary air intake port, and a primary exhaust valve provided at the primary exhaust port; the tertiary cylinder body is provided with a tertiary air intake port and a tertiary exhaust port, and is connected with a tertiary air intake and exhaust concentric valve and a tertiary cylinder pressure cover; the quaternary cylinder body is provided with a quaternary cylinder liner, the quaternary cylinder body is provided with a quaternary air intake port and a quaternary exhaust port, and is connected with a quaternary air intake and exhaust concentric valve and a quaternary cylinder pressure cover.

[0019] By adopting the above technical solution, suitable inlet and exhaust valves (conventional valves for the first and second stages, and concentric valves for the third and fourth stages) and gas ports are configured for each compression stage, optimizing the inlet and outlet paths of the gas at each stage and ensuring the smooth progress and compression efficiency of the compression process; in particular, the concentric valve structure is adopted in the third and fourth stages with higher pressures, which can optimize the airflow path, reduce the clearance volume, and improve the volumetric efficiency; the fourth-stage cylinder liner is arranged in the fourth-stage cylinder body, providing a wear-resistant working surface for the high-pressure piston head, extending the service life of the equipment and reducing the maintenance cost of the high-pressure stage cylinder.

[0020] Optionally, the second-stage cylinder block, the third-stage cylinder block, the first-stage cylinder block and the fourth-stage cylinder block are all provided with water inlets and outlets for cooling.

[0021] By adopting the above technical solution, by setting up a cooling water system on each level of cylinder body, the heat generated during the gas compression process can be effectively removed, the exhaust temperature at each level can be controlled, and the compressor can be ensured to operate within the allowable temperature range, thereby improving the operating reliability and efficiency of the compressor and extending the service life of related components such as piston rings and valves.

[0022] Optionally, super nuts are provided between the crankshaft connecting rod positioning structure and the second and third stage connecting rods and the first and fourth stage connecting rods for centering.

[0023] By adopting the above technical solution, through the use of super nut connection and the centering connecting rod and crankshaft connecting rod positioning structure, it is possible to ensure the precise alignment of moving parts, reduce assembly errors, ensure the smooth operation of the compressor, and reduce the additional vibration and wear that may be caused by poor alignment.

[0024] On the other hand, the present application also provides a compressor having the multi-stage compression piston group opposing structure.

[0025] The adoption of the above technical solution enables the compressor to have the comprehensive technical effects brought by the opposed structure of the multi-stage compression piston group, such as smooth operation, low vibration, low noise, compact structure, oil-free compression, high compression efficiency, easy maintenance and high operational reliability, thereby meeting the needs of modern industry for high-performance, environmentally friendly compressors.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. By symmetrically arranging the second- and third-stage piston-cylinder assemblies and the first- and fourth-stage piston-cylinder assemblies horizontally on opposite sides of the crankcase, with the piston groups driven in opposite directions by a double-throw crankshaft, the first-order reciprocating inertial forces generated by the piston groups are equal in magnitude and opposite in direction, canceling each other out along the crankshaft's central axis. This significantly reduces overall compressor vibration (down to ≤16mm / s) and noise (controllable to ≤88dBA), improving operational stability and operating comfort. This symmetrical, horizontally opposed layout also results in a lower center of gravity and a flatter, more compact structure (reducing footprint by 40%), making it easier to install and layout, making it particularly suitable for space-constrained applications. This structure also achieves four-stage compression, with a well-balanced pressure ratio distribution across each stage, which improves compression efficiency and reduces exhaust temperature. This allows for more precise control of the compression process, effective heat management, and reduced operating loads on key components, resulting in higher compression efficiency and longer component life. It is suitable for applications requiring high pressure and reliability.

[0027] 2. By using self-lubricating materials (such as PTFE composite materials) to make piston rings at all levels, the piston rings themselves can provide lubrication and can run smoothly in the cylinder without the need for external lubricating oil, thereby achieving oil-free compression of compressed gas, avoiding the risk of oil contamination, and meeting industrial applications with high requirements for gas cleanliness and environmental protection requirements.

[0028] 3. Appropriate inlet and exhaust valves (conventional valves for stages one and two, concentric valves for stages three and four) and gas ports are configured for each compression stage, optimizing the inlet and outlet paths of gas at each stage and ensuring a smooth and efficient compression process. In particular, the use of a concentric valve structure in the higher-pressure third and fourth stages optimizes the airflow path, reduces clearance volume, and improves volumetric efficiency. A fourth-stage cylinder liner is installed in the fourth-stage cylinder body, providing a wear-resistant working surface for the high-pressure piston head, extending the service life of the equipment and reducing maintenance costs for the high-pressure stage cylinders. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is an internal cross-sectional view of the opposed structure of the multi-stage compression piston group according to an embodiment of the present application; Figure 2 is an internal cross-sectional view from another angle of the opposed structure of the multi-stage compression piston group according to an embodiment of the present application; Figure 3 This is a schematic diagram of the external structure of the multi-stage compression piston group opposed structure of an embodiment of the present application; Figure 4 This is a schematic diagram of the external structure of the multi-stage compression piston group opposing structure of an embodiment of the present application from another angle.

[0030] Explanation of reference numerals: 10, crankcase; 20, crankshaft connecting rod positioning structure; 21, super nut; 31, first isolation chamber; 32, second isolation chamber; 33, oil scraper ring assembly; 41, second and third stage connecting rod; 42, second and third stage integrated piston; 43, second stage cylinder block; 44, second stage support ring; 45, second stage piston ring; 46, first stuffing box seal; 47, second stage air inlet; 47a, second stage air inlet valve; 48, second stage exhaust port; 48a, second stage exhaust valve; 49, second stage water inlet and outlet; 51, third stage cylinder block; 52, third stage support ring; 53, third stage piston ring; 54, third stage air inlet and exhaust concentric valve; 55, third stage cylinder gland; 56 6. Three-stage air inlet; 57. Three-stage exhaust port; 61. One-fourth-stage connecting rod; 62. One-stage double-acting piston; 63. One-stage cylinder body; 64. One-stage support ring; 65. One-stage piston ring; 66. Second stuffing box seal; 67. One-stage air inlet; 67a. One-stage air inlet valve; 68. One-stage exhaust port; 68a. One-stage exhaust valve; 69. One-stage water inlet and outlet; 71. Four-stage cylinder body; 72. Four-stage piston; 73. Four-stage support ring; 74. Four-stage piston ring; 75. Four-stage cylinder liner; 76. Four-stage intake and exhaust concentric valve; 77. Four-stage cylinder gland; 78a. Four-stage air inlet; 78b. Four-stage exhaust port; 79. Four-stage water inlet and outlet. DETAILED DESCRIPTION

[0031] The following is combined with Figure 1-4 This application is described in further detail.

[0032] The embodiment of the present application discloses a multi-stage compression piston group opposing structure.

[0033] Reference Figure 1 The multi-stage compression piston group opposing structure includes a crankcase 10, a crankshaft connecting rod positioning structure 20, and a second- and third-stage piston and cylinder assembly and a first- and fourth-stage piston and cylinder assembly symmetrically arranged relative to the crankshaft connecting rod positioning structure 20.

[0034] The second- and third-stage piston and cylinder assemblies are arranged horizontally symmetrically with the first- and fourth-stage piston and cylinder assemblies, allowing the pistons on both sides of the crankcase 10 to move synchronously and in opposite directions. During compressor operation, the reciprocating motion of the piston assemblies generates periodic inertial forces. In single-stage or asymmetrical compressors, these inertial forces can cause machine vibration. In contrast, in the multi-stage compression piston assembly configuration, a double-throw crankshaft drives the opposing piston assemblies in opposite directions. This ensures that when the pistons on one side (e.g., the first- and fourth-stage piston and cylinder assemblies) move outward, the pistons on the other side (e.g., the second- and third-stage piston and cylinder assemblies) simultaneously move inward. By precisely designing the crankshaft phasing and piston assembly mass, the first-order reciprocating inertial forces generated by these piston assemblies are equal in magnitude and opposite in direction, canceling each other outward along the crankshaft's central axis, significantly reducing overall machine vibration and noise. This force balance significantly reduces vibration throughout the compressor system, reducing vibration levels to ≤16 mm / s. The reduction in vibration also directly leads to a significant reduction in noise, and the noise value can be controlled at ≤88dBA. This is crucial for improving the stability of equipment operation and the comfort of the operating environment. In addition, the horizontally opposed second and third stage piston and cylinder assemblies and the first and fourth stage piston and cylinder assemblies are symmetrically arranged on both sides of the crankcase 10, making the center of gravity of the entire machine lower and the structure flatter. Compared with traditional V-type or L-type compressors (such as imported V-type compressors), this layout makes the overall structure of the equipment more compact. Its footprint can be reduced by 40%. This has significant advantages for installation environments with limited space, such as high-pressure gas supply scenarios in pumped storage systems.

[0035] In addition, the use of four-stage compression can effectively reduce the single-stage pressure ratio and optimize compression efficiency and temperature control. As the number of compression stages increases, the total compression ratio can be distributed to more levels, thereby reducing the compression ratio of each single stage. The lower the compression ratio, the smaller the increase in gas outlet temperature during isentropic or polytropic compression. Four-stage compression can effectively reduce the single-stage exhaust temperature (four stages ≤ 150°C)". Lower single-stage exhaust temperature helps protect subsequent components, especially sealing elements such as piston rings, and extend their service life. Lowering the single-stage exhaust temperature can reduce the thermal expansion effect of the gas, making the mass larger when the same volume of gas is inhaled, thereby improving the volumetric efficiency of the compressor. Combined with the cooling system (such as cooling water temperature ≤ 30°C), four-stage compression can better perform inter-stage cooling, further remove the compression heat, and thus improve the overall thermal efficiency.

[0036] When a very high final outlet pressure is required, if there are only three or fewer stages, the single-stage pressure ratio will be very large, leading to unmanageable ultra-high temperatures, high stresses, and material limitations. Four-stage compression gradually increases the pressure, allowing each stage to operate under more suitable operating conditions, making it easier to achieve high-pressure requirements while ensuring system stability and reliability. Furthermore, the reduction in single-stage exhaust temperature directly reduces the heat load and wear on moving sealing components such as piston rings. By properly allocating the pressure ratio and reducing the single-stage exhaust temperature, piston ring life can be extended. This is particularly important for oil-free compressors, as oil-free, self-lubricating piston rings (such as PTFE composites) are more sensitive to temperature.

[0037] In general, compared with three-stage or fewer stages of compression, four-stage compression can more finely control the compression process, effectively manage heat, and reduce the operating load of key components, thereby achieving higher compression efficiency and longer component life, and ultimately suitable for application scenarios with higher requirements for high pressure and high reliability.

[0038] The crankshaft connecting rod positioning structure 20 is disposed within the crankcase 10, with a first isolation chamber 31 and a second isolation chamber 32 defined on the first and second sides of the crankcase 10, respectively. The first and second sides of the crankshaft connecting rod positioning structure 20 are connected to the second and third connecting rods 41 and the fourth connecting rod 61, respectively. The crankshaft connecting rod positioning structure 20 can be connected and centered to the second and third connecting rods 41 and the fourth connecting rod 61, respectively, via superbolts 21, to ensure precise alignment of the moving parts.

[0039] The first isolation chamber 31 is located between the secondary cylinder block 43 and the crankcase 10, and the second isolation chamber 32 is located between the primary cylinder block 63 and the crankcase 10. The first isolation chamber 31 and the second isolation chamber 32 are both provided with an oil scraper ring assembly 33. The oil scraper ring assembly 33 is used to scrape off the lubricating oil from the crankcase (10) that may be attached to the secondary and tertiary connecting rods 41 and the first and fourth connecting rods 61, so as to ensure the cleanliness of the secondary and tertiary connecting rods 41 and the first and fourth connecting rods 61 in an oil-free lubrication environment.

[0040] The second and third stage piston and cylinder assembly includes second and third stage connecting rods 41 , second and third stage integrated pistons 42 , a second stage cylinder body 43 and a third stage cylinder body 51 .

[0041] The second and third stage connecting rods 41 are connected to the second and third stage integrated pistons 42. Figure 2The two-stage and three-stage integrated piston 42 has a two-stage portion and a three-stage portion. The two-stage portion is provided with a two-stage support ring 44 and a two-stage piston ring 45, and the three-stage portion is provided with a three-stage support ring 52 and a three-stage piston ring 53. The two-stage support ring 44 and the three-stage support ring 52 are used to support the radial position of the two-stage and three-stage integrated piston 42 within the two-stage cylinder body 43 and the three-stage cylinder body 51, thereby reducing contact wear between the two-stage and three-stage integrated piston 42 and the inner walls of the two-stage cylinder body 43 and the inner walls of the three-stage cylinder body 51. The two-stage piston ring 45 and the three-stage piston ring 53 are used to form a seal with the inner walls of the two-stage cylinder body 43 and the inner walls of the three-stage cylinder body 51, thereby preventing compressed gas from leaking from the high-pressure side to the low-pressure side, thereby ensuring compression efficiency. Optionally, the secondary piston ring 45 and the tertiary piston ring 53 are made of self-lubricating material (such as PTFE composite material), so that the secondary piston ring 45 and the tertiary piston ring 53 themselves can provide lubrication function without the need for external lubricating oil supply, thereby meeting environmental protection requirements and avoiding the risk of oil pollution.

[0042] The secondary cylinder body 43 is connected to the first isolation chamber 31, and a first stuffing box seal 46 is installed in the secondary cylinder body 43. The secondary and tertiary connecting rods 41 extend from the crankcase 10 through the first isolation chamber 31 and pass through the first stuffing box seal 46 into the secondary cylinder body 43. The first stuffing box seal 46 acts as a seal to prevent gas or liquid leakage between the secondary cylinder body 43 and the crankcase 10 (which needs to be lubricated with lubricating oil), ensuring that the compressed gas will not be contaminated by the lubricating oil in the crankcase 10. Figure 3 and Figure 4 The secondary cylinder body 43 is further provided with a secondary air intake port 47, a secondary exhaust port 48, and a secondary water inlet and outlet port 49. A secondary air intake valve 47a is provided at the secondary air intake port 47, and a secondary exhaust valve 48a is provided at the secondary exhaust port 48. The secondary air intake valve 47a is used to control the opening and closing of the secondary air intake port 47, and the secondary exhaust valve 48a is used to control the opening and closing of the secondary exhaust port 48. The secondary water inlet and outlet port 49 is used to connect the water system to the secondary cylinder body 43.

[0043] The three-stage cylinder body 51 is connected in series with the two-stage cylinder body 43, and the three-stage cylinder body 51 is connected to the three-stage intake and exhaust concentric valve 54 and the three-stage cylinder gland 55. Figure 3 and Figure 4The three-stage cylinder body 51 is provided with a three-stage air inlet 56, a three-stage exhaust port 57, and a three-stage water inlet and outlet 58. The three-stage air inlet and exhaust concentric valve 54 is used to control the intake of gas from the three-stage air inlet 56 and the exhaust of gas from the three-stage exhaust port 57 of the three-stage cylinder body 51. The three-stage water inlet and outlet 58 are used to connect the water system to the three-stage cylinder body 51.

[0044] The intake valve assembly of the three-stage concentric intake and exhaust valve 54 is coaxially arranged with the exhaust valve assembly, wherein the intake valve assembly of the three-stage concentric intake and exhaust valve 54 is arranged in an annular region inside or outside the exhaust valve assembly. The three-stage concentric intake and exhaust valve 54 can be an automatic valve driven by a pressure difference. Its opening and closing depends on the pressure difference between the inside and outside of the cylinder. When the pressure inside the cylinder is lower than the intake pressure, the intake valve assembly opens, and when the pressure inside the cylinder is higher than the exhaust pressure, the exhaust valve assembly opens. When the second- and third-stage integrated piston 42 descends (intake stroke), the pressure within the third-stage cylinder body 51 decreases, and the intake valve assembly (typically annular or multi-piece structure) of the third-stage intake and exhaust concentric valve 54 opens, allowing the gas compressed in the second stage to enter the third-stage cylinder body 51 from the third-stage intake port 56. When the second- and third-stage integrated piston 42 ascends (compression stroke), the pressure within the third-stage cylinder body 51 increases, and the intake valve assembly of the third-stage intake and exhaust concentric valve 54 closes, while the exhaust valve assembly (also annular or multi-piece structure) opens, allowing the gas compressed in the third stage to flow to the third-stage exhaust port 57 for discharge. The concentric valve structure optimizes the airflow path, allowing gas to efficiently enter and exit the third-stage intake and exhaust concentric valve, ensuring a smooth compression process. The third-stage cylinder gland 55 is used to secure or compress the third-stage intake and exhaust concentric valve 54 and ensure the sealing of this area to prevent gas leakage.

[0045] The four-stage piston and cylinder assembly includes a four-stage connecting rod 61 , a first-stage double-acting piston 62 , a first-stage cylinder body 63 and a fourth-stage cylinder body 71 .

[0046] The first double-acting piston 62 is sleeved on the first four-stage connecting rod 61, and the end of the first four-stage connecting rod 61 is constructed as a fourth-stage piston 72. Figure 2The first-stage double-acting piston 62 is provided with a first-stage support ring 64 and a first-stage piston ring 65, and the fourth-stage piston 72 is provided with a fourth-stage support ring 73 and a fourth-stage piston ring 74. The first-stage support ring 64 is used to support the radial position of the first-stage double-acting piston 62 in the first-stage cylinder body 63, thereby suppressing contact wear between the first-stage double-acting piston 62 and the inner wall of the first-stage cylinder body 63. The fourth-stage support ring 73 is used to support the radial position of the fourth-stage piston 72 in the fourth-stage cylinder body 71, thereby suppressing contact wear between the fourth-stage piston 72 and the fourth-stage cylinder liner 75. The first-stage piston ring 65 is used to form a seal with the inner wall of the first-stage cylinder body 63, and the fourth-stage piston ring 74 is used to form a seal with the fourth-stage cylinder liner 75 to prevent compressed gas from leaking from the high-pressure side to the low-pressure side, thereby ensuring compression efficiency. Optionally, the first-stage piston ring 65 and the fourth-stage piston ring 74 are made of self-lubricating material (such as PTFE composite material), so that the first-stage piston ring 65 and the fourth-stage piston ring 74 themselves can provide lubrication function without the need for external lubricating oil supply, thereby meeting environmental protection requirements and avoiding the risk of oil pollution.

[0047] The first-stage cylinder block 63 is connected to the second isolation chamber 32, and a second stuffing box seal 66 is provided in the first-stage cylinder block 63. The fourth-stage connecting rod 61 extends from the crankcase 10 through the second isolation chamber 32 and into the first-stage cylinder block 63 through the second stuffing box seal 66. The second stuffing box seal 66 acts as a seal to prevent gas or liquid leakage between the first-stage cylinder block 63 and the crankcase 10 (which requires lubrication with lubricating oil), ensuring that the compressed gas is not contaminated by the lubricating oil in the crankcase 10. Figure 3 and Figure 4 The primary cylinder body 63 is further provided with a primary air inlet 67, a primary exhaust port 68, and a primary water inlet and outlet 69. A primary air inlet valve 67a is provided at the primary air inlet 67, and a primary exhaust valve 68a is provided at the primary exhaust port 68. The primary air inlet valve 67a is used to control the opening and closing of the primary air inlet 67, and the primary exhaust valve 68a is used to control the opening and closing of the primary exhaust port 68. The primary water inlet and outlet 69 is used to connect the water system to the primary cylinder body 63.

[0048] The fourth-stage cylinder body 71 is connected to the first-stage cylinder body 63, and a fourth-stage cylinder liner 75 is provided in the fourth-stage cylinder body 71. The fourth-stage cylinder liner 75 is connected to the fourth-stage intake and exhaust concentric valve 76 and the fourth-stage cylinder gland 77. The fourth-stage piston 72 reciprocates in the fourth-stage cylinder liner 75. The fourth-stage compression is the last stage of compression, which makes it handle the highest gas pressure. The heat generated during the compression process and the friction between the piston and the cylinder wall may also be the most intense. Under high-pressure and high-wear environments, the inner wall of the cylinder is more susceptible to wear and damage. The fourth-stage cylinder liner 75 can provide a wear-resistant working surface for the fourth-stage piston 72. As a replaceable component, the fourth-stage cylinder liner 75 can be replaced separately after wear without replacing the entire fourth-stage cylinder body 71, thereby extending the service life of the equipment and reducing maintenance costs. In addition, in the highest pressure stage, the seal between the piston and the cylinder wall is crucial. The four-stage cylinder liner 75 can provide a high-precision inner surface to ensure that the four-stage piston ring 74 and the four-stage support ring 73 can form an effective seal with the cylinder wall to prevent leakage of high-pressure gas, thereby ensuring compression efficiency.

[0049] Refer again Figure 3 and Figure 4 The four-stage cylinder body 71 is provided with a four-stage air inlet 78a, a four-stage exhaust port 78b, and a four-stage water inlet and outlet 79. The four-stage air inlet and exhaust concentric valve 76 is used to control the intake of gas from the four-stage air inlet 78a and the exhaust of gas from the four-stage exhaust port 78b of the four-stage cylinder body 71. The four-stage water inlet and outlet 79 is used to connect the water system to the four-stage cylinder body 71.

[0050] The intake valve assembly of the four-stage intake and exhaust concentric valve 76 is coaxially arranged with the exhaust valve assembly, wherein the intake valve assembly of the four-stage intake and exhaust concentric valve 76 is arranged in an annular region inside or outside the exhaust valve assembly. The four-stage intake and exhaust concentric valve 76 can be an automatic valve driven by a pressure difference. Its opening and closing depends on the pressure difference between the inside and outside of the cylinder. When the pressure inside the cylinder is lower than the intake pressure, the intake valve assembly opens, and when the pressure inside the cylinder is higher than the exhaust pressure, the exhaust valve assembly opens. When the fourth-stage piston 72 descends (intake stroke), the pressure within the fourth-stage cylinder body 71 decreases, and the intake valve assembly (typically annular or multi-piece structure) of the fourth-stage intake and exhaust concentric valve 76 opens, allowing the gas compressed after the third stage to enter the fourth-stage cylinder body 71 through the fourth-stage intake port 78a. When the fourth-stage piston 72 ascends (compression stroke), the pressure within the fourth-stage cylinder body 71 increases, and the intake valve assembly of the fourth-stage intake and exhaust concentric valve 76 closes, while the exhaust valve assembly (also annular or multi-piece structure) opens, allowing the gas compressed after the fourth stage to flow to the fourth-stage exhaust port 78b for discharge. The concentric valve structure optimizes the airflow path, allowing gas to efficiently enter and exit the three-stage intake and exhaust concentric valve, ensuring a smooth compression process. The fourth-stage cylinder gland 77 secures or compresses the fourth-stage intake and exhaust concentric valve 76 and ensures a tight seal in this area to prevent gas leakage.

[0051] In general, the valve system of the present application utilizes conventional inlet valves (stage 1 inlet valve 67a, stage 2 inlet valve 47a) and exhaust valves (stage 1 exhaust valve 68a, stage 2 exhaust valve 48a) in the lower pressure stages (stages 1 and 2). The higher pressure stages (stages 3 and 4) utilize concentric valves (stage 3 inlet and exhaust concentric valve 54, stage 4 inlet and exhaust concentric valve 76) integrated with the cylinder glands (stage 3 gland 55, stage 4 gland 77) to achieve efficient gas flow.

[0052] The following describes the overall gas compression process and gas flow of the opposed multi-stage compression piston assembly. The compression process is divided into four stages, with gas sequentially compressed through the primary cylinder block 63, the secondary cylinder block 43, the tertiary cylinder block 51, and the quaternary cylinder block 71. Each stage is equipped with corresponding inlet and exhaust ports, as well as a cooling water system to manage the heat generated during the compression process.

[0053] During the first-stage compression process, external air enters the first-stage cylinder 63 through the first-stage air inlet 67. The first-stage air inlet valve 67a controls the air's entry. The first-stage double-acting piston 62 reciprocates within the first-stage cylinder 63, performing the first-stage compression of the air. The first-stage cylinder 63 is equipped with a cooling water channel, which is cooled via the first-stage water inlet and outlet 69. The first-stage compressed air is discharged from the first-stage exhaust port 68 through the first-stage exhaust valve 68a and connected to the second-stage cylinder 43 via an air pipe for the second-stage compression.

[0054] During the second-stage compression process, the gas compressed in the first stage enters the second-stage cylinder 43 through the second-stage intake port 47. The second-stage intake valve 47a controls the entry of gas. The second-stage / third-stage integrated piston 42 reciprocates within the second-stage cylinder 43, performing the second-stage compression of the gas. The second-stage cylinder 43 is provided with a cooling water channel, which is cooled through the second-stage water inlet and outlet ports 49. The gas compressed in the second stage is discharged from the second-stage exhaust port 48 through the second-stage exhaust valve 48a and connected to the third-stage cylinder 51 via an air pipe for the third-stage compression.

[0055] During the third-stage compression process, the gas compressed in the second stage enters the third-stage cylinder block 51 through the third-stage intake port 56. The intake valve assembly of the third-stage intake and exhaust concentric valve 54 controls the entry of the gas. The second- and third-stage integrated piston 42 reciprocates within the third-stage cylinder block 51, compressing the gas for a third time. The third-stage cylinder block 51 is provided with a cooling water channel, which is cooled through the third-stage water inlet and outlet ports 58. The gas compressed in the third stage is discharged from the third-stage exhaust port 57 through the exhaust valve assembly of the third-stage intake and exhaust concentric valve 54 and connected to the fourth-stage cylinder block 71 via an air pipe for the fourth-stage compression.

[0056] During the fourth-stage compression process, the gas compressed in the third stage enters the fourth-stage cylinder block 71 through the fourth-stage intake port 78a. The intake valve assembly of the fourth-stage intake and exhaust concentric valve 76 controls the entry of the gas. The fourth-stage piston 72 reciprocates within the fourth-stage cylinder block 71, performing the final fourth-stage compression of the gas. The fourth-stage cylinder block 71 is provided with a cooling water channel, which is cooled through the fourth-stage water inlet and outlet ports 79. The high-pressure gas after the fourth-stage compression is discharged from the fourth-stage exhaust port 78b through the exhaust valve assembly of the fourth-stage intake and exhaust concentric valve 76.

[0057] The piston and piston ring assembly of the present embodiment is implemented as follows: by symmetrically arranging the second and third stage piston and cylinder assemblies and the first and fourth stage piston and cylinder assembly horizontally opposite each other on either side of the crankcase 10, and using a double-throw crankshaft to drive the piston groups in opposite directions, the first-order reciprocating inertial forces generated by the piston groups are equal in magnitude and opposite in direction, thereby canceling each other out along the crankshaft's central axis. This significantly reduces the overall vibration (down to ≤16 mm / s) and noise (controllable to ≤88 dBA) during compressor operation, improving the equipment's operational stability and operating comfort. Furthermore, this symmetrical, horizontally opposed layout results in a lower center of gravity and a flatter and more compact structure (reducing floor space by 40%), making it easier to install and layout, making it particularly suitable for space-constrained applications. Furthermore, this structure achieves four-stage compression, resulting in a reasonable distribution of pressure ratios across each stage, which is beneficial for improving compression efficiency and reducing exhaust temperature. It also enables more precise control of the compression process, effectively manages heat, and reduces the operating load on key components, thereby achieving higher compression efficiency and longer component life. It is suitable for applications requiring higher pressure and reliability.

[0058] The embodiment of the present application also discloses a compressor having the aforementioned multi-stage compression piston group opposing structure.

[0059] The implementation principle of a compressor in an embodiment of the present application is: by applying the multi-stage compression piston group opposing structure to the compressor, the entire compressor has the comprehensive technical effects brought by the multi-stage compression piston group opposing structure, such as smooth operation, low vibration, low noise, compact structure, oil-free compression, high compression efficiency, easy maintenance and high operational reliability, thereby meeting the needs of modern industry for high-performance, environmentally friendly compressors.

[0060] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A multi-stage compression piston group opposing structure, characterized in that: include: A crankcase (10), wherein a crankshaft connecting rod positioning structure (20) is provided in the crankcase (10); The second and third stage piston and cylinder assembly is arranged on the first side of the crankcase (10), and the second and third stage piston and cylinder assembly includes a second and third stage connecting rod (41), a second and third stage integrated piston (42), a second cylinder body (43), and a third cylinder body (51) connected in series with the second cylinder body (43); the first end of the second and third stage connecting rod (41) is connected to the first side of the crankshaft connecting rod positioning structure (20), the second and third stage integrated piston (42) is connected to the second end of the second and third stage connecting rod (41), the second and third stage integrated piston (42) has a second part and a third part, the second part of the second and third stage integrated piston (42) cooperates with the second cylinder body (43) to perform second stage compression, and the third part of the second and third stage integrated piston (42) cooperates with the third cylinder body (51) to perform third stage compression; A four-stage piston and cylinder assembly is arranged on the second side of the crankcase (10), and the four-stage piston and cylinder assembly and the second and third stage piston and cylinder assemblies are symmetrically arranged relative to the crankshaft connecting rod positioning structure (20). The four-stage piston and cylinder assembly includes a four-stage connecting rod (61), a first-stage double-acting piston (62), a first-stage cylinder body (63), and a four-stage cylinder body (71) connected in series with the first-stage cylinder body (63). The first end of the four-stage connecting rod (61) is connected to the second side of the crankshaft connecting rod positioning structure (20), and the second end of the four-stage connecting rod (61) is constructed as a four-stage piston (72). The first-stage double-acting piston (62) is arranged on the four-stage connecting rod (61). The first-stage double-acting piston (62) cooperates with the first-stage cylinder body (63) to perform a first-stage compression, and the four-stage piston (72) cooperates with the four-stage cylinder body (71) to perform a fourth-stage compression.

2. The multi-stage compression piston group opposing structure according to claim 1, characterized in that: The second-stage portion of the second- and third-stage integrated piston (42) is provided with a second-stage piston ring (45) and a second-stage support ring (44); the third-stage portion of the second- and third-stage integrated piston (42) is provided with a third-stage piston ring (53) and a third-stage support ring (52); the first-stage double-acting piston (62) is provided with a first-stage piston ring (65) and a first-stage support ring (64); and the fourth-stage piston (72) is provided with a fourth-stage piston ring (74) and a fourth-stage support ring (73).

3. The multi-stage compression piston group opposing structure according to claim 2, characterized in that: The materials of the secondary piston ring (45), the tertiary piston ring (53), the primary piston ring (65) and the fourth piston ring (74) are self-lubricating materials.

4. The multi-stage compression piston group opposing structure according to claim 1, characterized in that: A first isolation chamber (31) is provided between the secondary cylinder block (43) and the crankcase (10), and a second isolation chamber (32) is provided between the primary cylinder block (63) and the crankcase (10).

5. The multi-stage compression piston group opposing structure according to claim 4, characterized in that: An oil scraper ring assembly (33) is provided inside the first isolation chamber (31) and the second isolation chamber (32). The oil scraper ring assembly (33) is used to scrape off the lubricating oil from the crankcase (10) attached to the second and third connecting rods (41) and the first and fourth connecting rods (61).

6. The multi-stage compression piston group opposing structure according to claim 4, characterized in that: A first stuffing box seal (46) is provided in the second-stage cylinder body (43), and the second- and third-stage connecting rods (41) extend into the second-stage cylinder body (43) through the first isolation chamber (31) and the first stuffing box seal (46); a second stuffing box seal (66) is provided in the first-stage cylinder body (63), and the fourth-stage connecting rod (61) extends into the first-stage cylinder body (63) through the second isolation chamber (32) and the second stuffing box seal (66).

7. The multi-stage compression piston group opposing structure according to claim 1, characterized in that: The secondary cylinder body (43) is provided with a secondary air inlet (47), a secondary air exhaust (48), a secondary air inlet valve (47a) provided at the secondary air inlet (47), and a secondary air exhaust valve (48a) provided at the secondary air exhaust (48); the primary cylinder body (63) is provided with a primary air inlet (67), a primary air exhaust (68), a primary air inlet valve (67a) provided at the primary air inlet (67), and a primary air exhaust valve (68) provided at the primary air exhaust (68). The first-stage exhaust valve (68a) is provided on the third-stage cylinder body (51); the third-stage air intake port (56) and the third-stage exhaust port (57) are provided on the third-stage cylinder body (51), and are connected to the third-stage air intake and exhaust concentric valve (54) and the third-stage cylinder gland (55); the fourth-stage cylinder body (71) is provided with a fourth-stage cylinder sleeve (75); the fourth-stage cylinder body (71) is provided with a fourth-stage air intake port (78a) and the fourth-stage exhaust port (78b), and are connected to the fourth-stage air intake and exhaust concentric valve (76) and the fourth-stage cylinder gland (77).

8. The multi-stage compression piston group opposing structure according to claim 1, characterized in that: The second-stage cylinder body (43), the third-stage cylinder body (51), the first-stage cylinder body (63), and the fourth-stage cylinder body (71) are all provided with water inlets and outlets (49, 58, 69, 79) for cooling.

9. The multi-stage compression piston group opposing structure according to claim 1, characterized in that: Super nuts (21) are provided between the crankshaft connecting rod positioning structure (20) and the second and third stage connecting rods (41) and the first and fourth stage connecting rods (61) for centering.

10. A compressor, characterized in that: A multi-stage compression piston group opposing structure having the structure described in any one of claims 1 to 9.

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