Mechanical limiting device for ionic liquid compressor liquid-driven piston

Abstract

The application provides a mechanical limiting device for a liquid-driven piston of an ionic liquid compressor, which comprises a cylinder body, a piston, a hydraulic cylinder and a hydraulic driving device, the piston is slidingly installed in the cylinder body, the cylinder body is assembled in butt joint with the hydraulic cylinder, the hydraulic driving device is used for supplying hydraulic oil to the hydraulic cylinder, a piston stroke limiter is installed at the inner wall of the hydraulic cylinder and the cylinder body, a buffer valve core is arranged at the lower end of the piston, the buffer valve core can slidingly pass through the center hole of the piston stroke limiter and extend into the interior of the hydraulic cylinder; compared with the existing hydrogen compressor, the buffer valve core and the limiting structure are arranged, so that the pressure of the hydraulic system can be automatically changed during the working of the hydraulic system, the movement state of the piston is adjusted, the generation of additional power consumption is reduced, and the influence of the free piston position being too low or colliding with the hydraulic cylinder on the service life of the compressor is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of compressors, and in particular relates to a mechanical limiting device for a liquid-driven piston of an ionic liquid compressor. Background Art

[0002] Hydrogen is hailed as the cleanest energy source of this century due to its abundant resources, the enormous energy released when completely burned, and the fact that it produces only water. Ionic liquid compressors are a new type of liquid piston compressor that uses ionic liquid as the liquid piston, replacing the traditional crankshaft connecting rod piston. This solves the problems of sealing, lubrication, and excessive piston size in previous compressors. This highly promising compressor has become the preferred choice for hydrogen refueling stations due to its advantages, and may also be used in the petrochemical industry for high-purity and toxic gases in the future.

[0003] Currently, ionic liquid compressors use a liquid-driven free piston, which reduces the number and volume of moving parts, but also causes the problem of unstable piston movement. Normally, when the free piston moves to near the top dead center or bottom dead center, the relief valve opens to release pressure, slowing the piston down and preventing the piston from colliding and causing mechanical damage. However, in actual operation, there is often a situation where the air pressure does not reach the set pressure, the oil pressure cannot reach the overflow pressure, and the relief valve cannot be opened, causing the piston to hit the cylinder. This not only affects the life of the compressor, but also causes a large amount of ionic liquid to be lost in the cylinder, consuming additional power. At the same time, if the piston position is too high, the actual air pressure will exceed the exhaust pressure. The speed of the free piston will become abnormal during exhaust, causing the liquid piston liquid level to fluctuate violently, causing too much ionic liquid to be discharged from the cavity, reducing the volumetric efficiency of the compressor.

[0004] In response to this phenomenon, researchers are gradually seeking solutions. For example, when we were reviewing the literature, we saw the patent document "A Multi-cylinder Pump Direct-Driven Ionic Liquid Compressor" by Lanzhou Lanshi Petroleum Equipment Engineering Co., Ltd., which provides an upper buffer boss at the upper end of the piston and a lower buffer boss at the lower end. The upper and lower ends of the cylinder body are respectively provided with an inner groove of the upper annular boss and a buffer groove at the lower end corresponding to the upper and lower buffer bosses. When the gas enters, after the lower buffer boss enters the buffer groove, the oil in the buffer groove flows out through the oil channel, and the oil in the drive chamber needs to pass through the adjustable lower buffer throttle valve to flow into the oil channel, and the throttling effect buffers the compression cylinder. When compressing the gas, after the upper buffer boss enters the inner groove of the annular boss, the gas outside the annular boss continues to be discharged from the gas channel, and the inner groove of the annular boss is filled with ionic liquid. This part of the ionic liquid flows into the compression chamber through the adjustable upper buffer throttle valve, and the throttling effect buffers the compression cylinder. Summary of the Invention

[0005] Based on the above technical status, the present invention has made improvements on the existing technology and designed a mechanical limit device for the liquid-driven piston of an ionic liquid compressor. The original structural design of the hydrogen compression space above the piston is retained to avoid pressure fluctuations during hydrogen compression. A buffer valve core structure is designed below the piston to achieve a self-pressure buffering effect when the piston rises to the highest point and falls to the lowest point.

[0006] The technical solution adopted by the present invention is as follows: a mechanical limiting device for the liquid-driven piston of an ionic liquid compressor, comprising a cylinder body, a piston, a hydraulic cylinder and a hydraulic drive device, wherein the piston is slidably installed in the cylinder body, the cylinder body and the hydraulic cylinder are docked and assembled, and the hydraulic drive device is used to supply hydraulic oil to the hydraulic cylinder.

[0007] A piston stroke limiter is installed on the inner wall of the hydraulic cylinder and the cylinder body, and a buffer valve core is provided at the lower end of the piston, and the buffer valve core can slide through the center hole of the piston stroke limiter and extend into the interior of the hydraulic cylinder; a hydraulic cavity is formed between the upper end surface of the piston stroke limiter, the outer peripheral surface of the buffer valve core and the lower end surface of the piston, and the internal space of the hydraulic cylinder below the buffer valve core is connected with the hydraulic cavity via a hydraulic oil channel opened in the buffer valve core, and a throttle valve is provided in the hydraulic oil channel; a lateral channel connected to the hydraulic oil channel is also opened on the buffer valve core, and a one-way valve is provided on the lateral channel, and the one-way valve allows hydraulic oil to flow from the side of the buffer valve core through the one-way valve into the hydraulic oil channel.

[0008] A secondary step hole is provided in the hydraulic cylinder, and the inner diameter of the first step hole of the secondary step hole is smaller than the inner diameter of the cylinder body, thereby forming a first step surface between the contact surface of the cylinder body and the hydraulic cylinder, and the second step hole of the secondary step hole is located below the first step hole and has an inner diameter smaller than the inner diameter of the first step hole, thereby forming a second step surface between the first step hole and the second step hole; the shape of the piston stroke limiter is adapted to the secondary step hole and the two step surfaces.

[0009] Furthermore, the piston stroke limiter is an annular cylindrical structure with a variable diameter outer wall, and its inner diameter is adapted to the inner diameter of the second-level step hole, and a necking portion is formed near the upper position of the inner diameter. The outer diameter of the piston stroke limiter includes a large diameter portion and a small diameter portion, and the large diameter portion and the small diameter portion are connected by a transition step. The large diameter portion is adapted to the inner diameter of the cylinder body, and the two are relatively fixedly installed; the small diameter portion is adapted to the inner diameter of the first-level step hole, and the small diameter portion of the piston stroke limiter is fixedly installed in the first-level step hole, and the lower end face of the small diameter portion abuts the second-level step surface; the inner diameter of the necking portion is adapted to the outer diameter of the buffer valve core, so that the buffer valve core can slide along the necking portion and block the hydraulic oil from entering the hydraulic chamber from the hydraulic cylinder along the outer wall of the buffer valve core.

[0010] The through hole is provided on the buffer valve core and penetrates through both sides of the buffer valve core, the upper end of the hydraulic oil channel is communicated with the through hole, and the through hole is provided at a position corresponding to the hydraulic cavity to communicate the hydraulic oil channel with the hydraulic cavity. When the piston reciprocates between the highest point and the lowest point, the through hole is always communicated with the hydraulic cavity, and the lateral channel with the one-way valve is always below the necked portion of the piston stroke limiter.

[0011] Preferably, the buffer valve core is integrally formed at the bottom of the piston, or the buffer valve core is fixedly installed at the bottom of the piston coaxially with the piston.

[0012] Further, the communication point of the lateral channel with the one-way valve with the hydraulic oil channel is above the throttle valve.

[0013] Preferably, the gas path system comprises an air inlet pipeline, an air outlet pipeline, an air inlet valve and an air outlet valve, the air inlet valve and the air outlet valve are installed on a valve seat, the valve seat is arranged at the hydrogen compression end of the cylinder body, a pressing plate is fixedly arranged above the valve seat, the air inlet pipeline penetrates through the pressing plate and is communicated with the air inlet valve, and the air outlet pipeline penetrates through the pressing plate and is communicated with the air outlet valve.

[0014] Preferably, the through channel can be provided with one or more circumferential distributions, and the lateral channel can be provided with one or more circumferential distributions.

[0015] The beneficial technical effects of the present application are that:

[0016] Compared with the existing hydrogen compressor, the buffer valve core and the limiting structure can change the pressure of the hydraulic system during operation, adjust the piston movement, reduce the generation of additional power consumption, and avoid the impact of the free piston position being too low or colliding with the hydraulic cylinder on the service life of the compressor. Compared with the reference technology in the background art, the present application only relies on the buffer valve core and the limiting structure at the bottom of the piston to realize the self-pressure buffering of the piston position being too high or too low, the hydrogen compression space on the upper end surface of the piston is not affected, and the structure is relatively simple and convenient to assemble. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a system structure diagram of the mechanical limiting device of the ionic liquid compressor hydraulic piston of the present application;

[0018] Figure 2 is an enlarged sectional view of the buffer valve core of the mechanical limiting device of the ionic liquid compressor hydraulic piston of the present application;

[0019] Figure 3 is a working schematic view of the buffer valve core when the piston rises to the highest point;

[0020] Figure 4This is a schematic diagram of the buffer valve core working when the piston drops to the lowest point;

[0021] In the figure: 1. Hydraulic cylinder, 2. Throttle valve, 3. Check valve, 4. Piston stroke limiter, 5. Hydraulic chamber, 6. Cylinder body, 7. Piston, 8. Ionic liquid, 9. Inlet pipe, 10. Exhaust pipe, 11. Pressure plate, 12. Valve seat, 13. Exhaust valve, 14. Inlet valve, 15. Through hole, 16. Hydraulic oil channel, 17. Buffer valve core, 18. Hydraulic oil. DETAILED DESCRIPTION

[0022] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other.

[0023] The following detailed description is an exemplary description and is intended to provide further detailed description of the present invention. Unless otherwise indicated, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present invention belongs. The terms used in the present invention are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention.

[0024] Figure 1 This is a system structure diagram of the mechanical limit device of the liquid-driven piston of the ionic liquid compressor of the present invention, including an air circuit system and a compression component; the air circuit system includes an intake pipe 9, an exhaust pipe 10, an intake valve 14 and an exhaust valve 13, the intake valve 14 and the exhaust valve 13 are installed on the valve seat 12, the valve seat 12 is placed on the hydrogen compression end of the cylinder body 6, a pressure plate 11 is fixed above the valve seat 12, the intake pipe 9 passes through the pressure plate 11 to communicate with the intake valve 14, and the exhaust pipe 10 passes through the pressure plate 11 to communicate with the exhaust valve 13; the compression component includes a cylinder body 6 and a piston 7 installed inside the cylinder body 6, the upper end surface of the piston 7 has an appropriate amount of ionic liquid 8, and the air circuit system is a conventional hydrogen compressor intake and exhaust structure, which is only briefly described here. The improvement of the present invention lies in the structural redesign of the mechanical limit device and the hydraulic drive device, see Figure 1The hydraulic cylinder 1 is connected to the bottom of the cylinder body 6, and the piston 7 is accommodated in the cylinder body 6 and driven to reciprocate. A two-level step hole is opened in the hydraulic cylinder 1. The inner diameter of the first-level step hole of the two-level step hole is smaller than the inner diameter of the cylinder body 6, thereby forming a first-level step surface between the contact surface of the cylinder body 6 and the hydraulic cylinder 1. The second-level step hole of the two-level step hole is located below the first-level step hole and has an inner diameter smaller than the inner diameter of the first-level step hole, thereby forming a second-level step surface between the first-level step hole and the second-level step hole. A piston stroke limiter 4 is installed between the cylinder body 6 and the hydraulic cylinder 1. The piston stroke limiter 4 is an annular tube structure with a variable diameter outer wall. Its inner diameter is the same as or similar to the inner diameter of the second-level step hole, and a necking portion is formed near the upper position of the inner diameter. The outer diameter of the piston stroke limiter 4 includes a large diameter portion and a small diameter portion, and the large diameter portion and the small diameter portion are connected by an intermediate step. The large diameter portion is adapted to the inner diameter of the cylinder body 6, and the two are interference fit or threaded. The large diameter portion of the piston stroke limiter 4 is installed inside the cylinder body 6, and the small diameter portion is adapted to the inner diameter of the first-level step hole. The small diameter portion of the piston stroke limiter 4 is fixedly installed in the first-level step hole, and the lower end face of the small diameter portion abuts against the second-level step surface.

[0025] The lower end of the piston 7 is fixedly connected to the buffer valve core 17 in an integral or split manner. The outer diameter of the buffer valve core 17 is adapted to the inner diameter of the constricted portion of the piston stroke limiter 4 so that the buffer valve core 17 passes through the constricted portion and extends into the hydraulic cylinder 1; a hydraulic chamber 5 is formed between the piston stroke limiter 4 and the piston 7.

[0026] See also Figure 2 , is an enlarged cross-sectional view of the buffer valve core of the mechanical limit device for the hydraulically driven piston of the ionic liquid compressor of the present invention. The buffer valve core 17 has an axially extending hydraulic oil passage 16 and transversely extending through-holes 15 on both sides of the buffer valve core. The pipe through-holes 15 are located at positions corresponding to the hydraulic chamber 5. The lower end of the hydraulic oil passage 16 communicates with the interior of the hydraulic cylinder 1 via the throttle valve 2, and the upper end of the hydraulic oil passage 16 communicates with the through-holes 15, thereby connecting the interior space of the hydraulic cylinder 1 with the hydraulic chamber 5. The buffer valve core 17 also has a lateral passage connected to the hydraulic oil passage 16. A one-way valve 3 is disposed in the lateral passage. The one-way valve 3 allows hydraulic oil to flow from the side of the buffer valve core through the one-way valve 3 into the hydraulic oil passage 16.

[0027] The opening position of the through hole 15 can keep the piston 7 always connected to the hydraulic chamber 5 when it reciprocates between the highest point and the lowest point; the opening position of the lateral channel of the one-way valve 3 can keep the piston 7 always located below the necking part of the piston stroke limiter 4 when it reciprocates between the highest point and the lowest point, and the necking part blocks the hydraulic oil 18 from flowing from the hydraulic cylinder 1 along the annular gap between the buffer valve core 17 and the piston stroke limiter 4 to the hydraulic chamber 5.

[0028] Figure 1 and Figure 2 The structural design of the mechanical limit device and the hydraulic drive device of the present invention is shown in detail. Figure 3 and Figure 4 The working principle of the mechanical limit device of the liquid-driven piston of the ionic liquid compressor of the present invention is explained as follows:

[0029] During operation, it is divided into an intake process and a compression process. The gas enters the cylinder through the intake pipe 9 and the intake valve 14. The hydraulic pump in the hydraulic drive device moves, driving the hydraulic oil 18 to enter the hydraulic cylinder 1 to generate power, pushing the piston 7 up to compress the gas; when the pressure in the cylinder reaches the exhaust pressure, the exhaust valve 13 opens, and the gas is discharged through the exhaust pipe 10. During the compression process, when the piston 7 rises to the designed height, the liquid piston position reaches the top of the cylinder, the pressure on the top of the piston 7 increases sharply, and the throttle valve 2 at the bottom of the buffer valve core 17 reduces the flow rate due to the pressure difference. The hydraulic oil flows through the one-way valve 3 on the lower surface of the buffer valve core 17 through the hydraulic oil channel into the hydraulic chamber 5, and converges at the bottom of the hydraulic chamber 5, causing the liquid pressure in the hydraulic cylinder 1 to drop sharply, preventing the piston position from continuing to rise.

[0030] During the intake process, when the position of the piston 7 drops, the through hole 15 on the upper part of the buffer valve core 17 gradually drops below the hydraulic oil level in the hydraulic chamber 5. The hydraulic oil flows along the through hole 15 into the hydraulic oil channel 16 and re-enters the hydraulic cylinder 1 through the throttle valve 2, increasing the pressure in the hydraulic cylinder 1, thereby preventing the piston position from continuing to drop.

[0031] The mechanical limit device of the liquid-driven piston of the ionic liquid compressor of the present invention can spontaneously adjust the power provided by the hydraulic oil in the hydraulic cylinder to the piston, thereby preventing the free piston from colliding with other parts of the compressor due to the free piston moving too high or too low, thereby shortening the life of the compressor. At the same time, the loss of ionic liquid in the cylinder is prevented, thereby improving economic benefits.

[0032] It is understood from common technical knowledge that the present invention may be implemented by other embodiments that do not depart from its spirit or essential features. Therefore, the embodiments disclosed above are, in all respects, merely illustrative and not exclusive. All modifications within the scope of the present invention or equivalent to the scope of the present invention are intended to be encompassed by the present invention.

Claims

1. A mechanical limiter for a hydraulically driven piston in an ionic liquid compressor, comprising a cylinder body, a piston, a hydraulic cylinder, and a hydraulic drive device, wherein the piston is slidably mounted in the cylinder body, the cylinder body and the hydraulic cylinder are butt-jointed and assembled, and the hydraulic drive device is used to supply hydraulic oil to the hydraulic cylinder; characterized in that: A piston stroke limiter is installed on the inner wall of the hydraulic cylinder and the cylinder body, and a buffer valve core is provided at the lower end of the piston, and the buffer valve core can slide through the center hole of the piston stroke limiter and extend into the interior of the hydraulic cylinder; a hydraulic chamber is formed between the upper end surface of the piston stroke limiter, the outer peripheral surface of the buffer valve core, and the lower end surface of the piston, and the internal space of the hydraulic cylinder below the buffer valve core is connected with the hydraulic chamber via a hydraulic oil channel provided in the buffer valve core, and a throttle valve is provided in the hydraulic oil channel; a lateral channel connected to the hydraulic oil channel is also provided on the buffer valve core, and a one-way valve is provided on the lateral channel, and the one-way valve allows hydraulic oil to flow from the side of the buffer valve core through the one-way valve into the hydraulic oil channel; The buffer valve core is provided with a through hole which passes through both sides of the buffer valve core laterally, and the upper end of the hydraulic oil channel is connected with the through hole. The through hole is provided at a position corresponding to the hydraulic cavity to connect the hydraulic oil channel with the hydraulic cavity.

2. The mechanical limiting device for the liquid-driven piston of the ionic liquid compressor according to claim 1, further characterized in that: A two-stage stepped hole is provided in the hydraulic cylinder, wherein the inner diameter of the first stage stepped hole of the two-stage stepped hole is smaller than the inner diameter of the cylinder body, thereby forming a first stage stepped surface between the contact surface of the cylinder body and the hydraulic cylinder, and the second stage stepped hole of the two-stage stepped hole is located below the first stage stepped hole and has an inner diameter smaller than the inner diameter of the first stage stepped hole, thereby forming a second stage stepped surface between the first stage stepped hole and the second stage stepped hole; The shape of the piston stroke limiter is adapted to the secondary step hole and the two-step surface.

3. The mechanical limit device for the liquid-driven piston of the ionic liquid compressor according to claim 2, further characterized in that: The piston stroke limiter is a ring-shaped cylindrical structure with a variable diameter outer wall, and its inner diameter is adapted to the inner diameter of the second-stage stepped hole, and a constricted portion is formed near the upper position of the inner diameter. The outer diameter of the piston stroke limiter includes a large diameter portion and a small diameter portion, and the large diameter portion and the small diameter portion are connected by a transition step. The large diameter portion is adapted to the inner diameter of the cylinder body, and the two are relatively fixedly installed; the small diameter portion is adapted to the inner diameter of the first-stage stepped hole, and the small diameter portion of the piston stroke limiter is fixedly installed in the first-stage stepped hole, and the lower end surface of the small diameter portion abuts against the second-stage stepped surface; The inner diameter of the constricted portion is adapted to the outer diameter of the buffer valve core, so that the buffer valve core can slide along the constricted portion and prevent hydraulic oil from entering the hydraulic cavity from the hydraulic cylinder along the outer peripheral wall of the buffer valve core.

4. The mechanical limiting device for the liquid-driven piston of the ionic liquid compressor according to claim 1 is further characterized in that: When the piston reciprocates between the highest point and the lowest point, the through hole is always connected to the hydraulic chamber, and the lateral channel where the one-way valve is installed is always located below the necked portion of the piston stroke limiter.

5. The mechanical limiting device for the liquid-driven piston of the ionic liquid compressor according to claim 1 is further characterized in that: The buffer valve core is integrally formed on the bottom of the piston; or the buffer valve core is coaxially fixedly installed on the bottom of the piston with the piston.

6. The mechanical limiting device for the liquid-driven piston of the ionic liquid compressor according to claim 1, further characterized in that: The connection point between the lateral channel where the one-way valve is installed and the hydraulic oil channel is located above the throttle valve.

7. The mechanical limiting device for the liquid-driven piston of the ionic liquid compressor according to claim 1 is further characterized in that: It also includes an air circuit system, which includes an intake pipe, an exhaust pipe, an intake valve and an exhaust valve. The intake valve and the exhaust valve are installed on a valve seat. The valve seat is placed on the hydrogen compression end of the cylinder body. A pressure plate is fixed above the valve seat. The intake pipe passes through the pressure plate to communicate with the intake valve, and the exhaust pipe passes through the pressure plate to communicate with the exhaust valve.

8. The mechanical limiting device for the liquid-driven piston of the ionic liquid compressor according to claim 1, further characterized in that: The through-holes may be provided in one or more circumferentially distributed positions; the lateral channels may be provided in one or more circumferentially distributed positions.

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