Device, system and method for adjusting air displacement of reciprocating compressor

Abstract

The invention belongs to the field of displacement adjustment of reciprocating compressors, and discloses a device, a system and a method for adjusting the displacement of a reciprocating compressor. The device comprises a pneumatic mechanism, a supporting mechanism and a pressing claw assembly. The pneumatic mechanism comprises a diaphragm box, a diaphragm, a valve rod and a diaphragm reset component. The diaphragm capsule is provided with an air cavity, the diaphragm is arranged in the air cavity and divides the air cavity into a working cavity and a balance cavity, the position of the diaphragm is changed along with the pressure difference change of the working cavity and the balance cavity, and the working cavity is communicated with an external air supply pipeline. One part of the valve rod is connected to the diaphragm, and the other part of the valve rod extends out of the diaphragm capsule. The diaphragm reset component moves the diaphragm to an initial position when needed. The pressing claw assembly comprises a pressing claw, and the pressing claw assembly can utilize the pressing claw to eject open a valve plate of the air inlet valve under the downward pressing effect of the valve rod so that the air inlet valve can be in a normally-open state. According to the device, the system and the method, the purposes of automatically adjusting the gas displacement of the reciprocating compressor and reducing the energy consumption of the reciprocating compressor can be achieved with low cost.

Description

Technical Field

[0001] This invention relates to the field of reciprocating compressor discharge volume regulation, and more particularly to a device, system and method for regulating the discharge volume of a reciprocating compressor. Background Technology

[0002] Reciprocating compressors are characterized by a high compression ratio and relatively small gas delivery capacity, and are widely used in petrochemical plants and long-distance pipeline gas applications. (Appendix) Figure 1 A simplified structural diagram of a reciprocating compressor cylinder is shown. The cylinder includes components such as a cylinder body A1, a piston A2, and a piston rod A3. The cylinder body A1 has an intake valve V1 and an exhaust valve V2 on the side near the cylinder head, and an intake valve V3 and an exhaust valve V4 on the side near the crankshaft. The reciprocating compressor relies on the reciprocating motion of the piston A2 inside the cylinder to draw in gas through the intake valve V1 or V3 at the top of the cylinder and to discharge gas through the exhaust valve V2 or V4 at the bottom of the piston. In actual operation, the reciprocating compressor often needs to adjust its discharge volume in real time according to changes in production conditions to ensure that the compressor can meet production needs under optimal conditions.

[0003] There are several methods for adjusting the discharge capacity of reciprocating compressors in related technologies. Common methods include bypass adjustment, variable clearance adjustment, and frequency conversion adjustment.

[0004] Bypass regulation is a method of regulating gas that is high-temperature, high-pressure gas from the compressor outlet is returned to the compressor inlet via a regulating valve. While it can effectively regulate the gas volume required by the production system, the energy consumption of the reciprocating compressor is not reduced. Moreover, due to the very large pressure difference across the regulating valve, there are drawbacks such as valve wear, noise, and vibration.

[0005] Variable clearance adjustment is achieved by adjusting the clearance of the reciprocating compressor cylinder, thereby increasing the clearance volume and decreasing the volumetric coefficient, thus reducing the compressor's discharge capacity. This method requires manual adjustment and has a slow response time.

[0006] Variable frequency drive (VFD) regulation adjusts the discharge volume by changing the rotational speed of a reciprocating compressor. The advantages of this method include continuous airflow, low power consumption, constant pressure ratios at each stage of the compressor, and no need for a dedicated adjustment mechanism. However, VFD motors and inverters require significant investment, and variable speed regulation may negatively impact compressor operation, such as causing valve chatter, excessive component wear, increased vibration, and insufficient lubrication.

[0007] Furthermore, patent CN107228068A discloses a method for stepless air volume regulation of a reciprocating compressor. This method is based on the fundamental principle of regulating air volume by opening the intake valve. It employs full-cycle variable force loading to control the air volume of the reciprocating compressor, achieving stepless regulation of air volume from 0 to 100% of the full scale, resulting in significant energy savings. However, this method uses a hydraulic regulating circuit to open the intake valve to regulate the intake volume, requiring the installation of hydraulic control components such as a hydraulic oil pump and hydraulic pipelines. The hydraulic oil is used to control the movement of the intake valve plate of the reciprocating compressor. This regulation method involves high investment in the hydraulic oil system, requires external power to drive the hydraulic oil pump, and is technically difficult to maintain daily, making it prone to damage.

[0008] Patent CN203175826U discloses a reciprocating piston compressor discharge volume regulating device. This device includes a compressor control system. The main cable of the control system is connected to a variable frequency main motor via a circuit breaker and a frequency converter. A pressure transmitter for collecting discharge pressure is installed on the compressor's discharge line. The pressure transmitter is electrically connected to the frequency converter via a signal line, providing a 4-20mA signal to the frequency converter. When the discharge pressure is higher than the design pressure, the compressor speed is reduced by the frequency converter; when the discharge pressure is lower than the design pressure, the speed is increased by the frequency converter, thus regulating the discharge volume. This regulation method requires the installation of a frequency converter and a variable frequency main motor. Especially when the reciprocating compressor has high power and the motor is a 10KV high-voltage motor, replacing the high-voltage frequency converter and high-voltage variable frequency motor is costly. Furthermore, when the motor speed changes, the vibration of the reciprocating compressor increases, causing valve chatter, a drop in lubricating oil pressure, and insufficient lubrication of parts.

[0009] Therefore, there is still much room for improvement in the adjustment of the discharge capacity of reciprocating compressors. Summary of the Invention

[0010] To address the aforementioned problems, this invention provides a device, system, and method for adjusting the discharge capacity of a reciprocating compressor, thereby achieving automatic adjustment of the discharge capacity of the reciprocating compressor and reducing its energy consumption.

[0011] According to one aspect of the present invention, an apparatus for adjusting the discharge capacity of a reciprocating compressor is provided, the apparatus comprising: A pneumatic mechanism includes a diaphragm, a diaphragm, a valve stem, and a diaphragm reset component. The diaphragm has an air chamber, and the diaphragm is disposed within the air chamber. The diaphragm divides the air chamber into an independent working chamber and a balance chamber, and changes position according to the pressure difference between the working chamber and the balance chamber. The working chamber is connected to an external air supply line. A first part of the valve stem is inserted into the balance chamber and connected to the diaphragm, and a second part of the valve stem extends outside the diaphragm. The diaphragm reset component is connected to the diaphragm to move the diaphragm to an initial position when the pressure difference between the working chamber and the balance chamber meets a predetermined condition. A support mechanism is connected to the outside of the diaphragm box to support the pneumatic mechanism on the outer wall of the cylinder of the reciprocating compressor, and a second portion of the valve stem extends through the body of the support mechanism; The pressure claw assembly includes a pressure claw seat, which has a receiving groove for accommodating the top component of the intake valve of the reciprocating compressor. The end of the pressure claw seat is provided with a pressure claw, which can be inserted into the intake passage of the intake valve. Under the downward pressure of the second part of the valve stem, the pressure claw seat can push open the valve plate of the intake valve to open the intake valve.

[0012] According to one embodiment of the present invention, the diaphragm is switchable between an initial position and a depressed position. In the initial position, a first gap exists between the end of the second portion of the valve stem and the top of the pressure claw seat, and the pressure claw does not apply pressure to the valve plate, such that the valve plate is in a closed position that closes the air intake passage. In the depressed position, the end of the second portion of the valve stem presses against the top of the pressure claw seat to cause the pressure claw to press the valve plate down to an open position that connects the air intake passage with the cylinder interior of the reciprocating compressor.

[0013] According to one embodiment of the present invention, the travel distance between the initial position and the pressed position is matched with the distance the valve plate moves from the closed position to the open position.

[0014] According to one embodiment of the present invention, the pressure claw assembly further includes a pressure claw reset component, which is disposed in the receiving groove and causes the pressure claw seat to spring back after the valve stem disengages from the pressure claw seat. The first gap is set so that the pressure claw seat does not collide with the end of the valve stem during the springback.

[0015] According to one embodiment of the present invention, the diaphragm reset component is a spring disposed in the balance cavity, the spring being sleeved on the valve stem and having its two ends abutting against the diaphragm and the diaphragm box, respectively.

[0016] According to one embodiment of the present invention, the support mechanism includes a valve hole cover and a support flange. The valve hole cover is used to close the valve hole opened on the cylinder wall of the reciprocating compressor for installing the intake valve, and the support flange is disposed between the diaphragm and the valve hole cover.

[0017] According to one embodiment of the present invention, a first through hole is provided at the center of the valve hole cover, a second through hole is provided at the center of the support flange, and a second part of the valve stem extends through the first through hole and the second through hole.

[0018] According to one embodiment of the present invention, the gap between the wall of the first through hole and the surface of the valve stem is sealed by a sealing element.

[0019] According to one embodiment of the present invention, the device further includes a leak detection component, wherein a detection channel is provided in the peripheral wall of the supporting flange, the detection channel is connected to the second through hole, and the detection channel is also connected to a sensor for detecting gas leaks.

[0020] According to one embodiment of the present invention, the device further includes a gas supply mechanism, which includes a gas source, a gas supply pipeline and a control valve. The gas supply pipeline connects the working chamber to the gas source, and the control valve is disposed in the gas supply pipeline.

[0021] According to one embodiment of the present invention, the control valve is a two-position three-way solenoid valve, wherein the first gas port of the solenoid valve is connected to the gas source, the second gas port is connected to the working chamber, and the third gas port is connected to the external environment.

[0022] According to one embodiment of the present invention, the solenoid valve is controlled to switch between a first state and a second state, wherein in the first state, the solenoid valve is energized to connect the gas source to the working chamber, and in the second state, the solenoid valve is de-energized to connect the working chamber to the external environment.

[0023] According to another aspect of the present invention, a system for regulating the discharge capacity of a reciprocating compressor is provided, the system comprising: A pressure sensor is installed in the first-stage cylinder of the reciprocating compressor to detect the inlet pressure; The device for adjusting the discharge volume of a reciprocating compressor according to any of the above embodiments; The controller receives information detected by the pressure sensor and controls the operation of the device for adjusting the discharge volume of the reciprocating compressor based on a comparison of the information with an inlet pressure setpoint stored in the controller.

[0024] According to one embodiment of the present invention, the device for adjusting the discharge volume of the reciprocating compressor is installed on the intake valve on the cylinder head side of the first-stage cylinder.

[0025] According to one embodiment of the present invention, the system further includes a human-machine interface device that provides an operator with manual control options and automatic control options. When the manual control option is selected, the operator controls the operation of the device for adjusting the discharge capacity of the reciprocating compressor. When the automatic control option is selected, the controller controls the operation of the device for adjusting the discharge capacity of the reciprocating compressor based on a comparison between the gas pressure information and the inlet pressure setpoint.

[0026] According to one embodiment of the present invention, the controller is configured to perform the following operations when the automatic control option is selected: When the detected inlet air pressure is lower than the inlet pressure set value, the external air supply line is activated to pressurize the working chamber of the pneumatic mechanism to move the valve plate of the inlet valve to the open position. When the detected inlet air pressure is not lower than the inlet pressure set value, the working chamber of the pneumatic mechanism is controlled to exhaust air, so that the valve plate of the inlet valve moves to the closed position.

[0027] According to one embodiment of the present invention, when the device for adjusting the discharge volume of the reciprocating compressor is provided with a two-position three-way solenoid valve, the controller controls the operation of the pneumatic mechanism by controlling the energization and de-energization of the solenoid valve.

[0028] According to one embodiment of the present invention, the system further includes a timer that counts and records the time when the reciprocating compressor is in operation and the solenoid valve is energized, and the controller calculates the cumulative energy savings of the reciprocating compressor based on the recorded cumulative duration.

[0029] According to another aspect of the present invention, a method for adjusting the discharge capacity of a reciprocating compressor using a system as described in any of the above embodiments is provided, the method comprising the following steps: The inlet pressure setpoint is stored in the controller. The inlet pressure setpoint is used as the threshold for switching the intake valve of the first stage cylinder of the reciprocating compressor to the normally open state. The inlet air pressure of the first-stage cylinder detected by the air pressure sensor is compared with the inlet pressure set value; In response to the detected air pressure being lower than the inlet pressure set value, air is injected into the working chamber of the pneumatic mechanism to move the valve plate of the inlet valve to the open position; In response to the detected air pressure not being lower than the inlet pressure set value, the working chamber is controlled to exhaust air, so that the valve plate of the intake valve moves to the closed position.

[0030] Due to the adoption of the above technical solutions, the device, system, and method for adjusting the discharge volume of a reciprocating compressor provided by the present invention have at least one of the following advantages compared with the prior art: The device of the present invention achieves position adjustment of the pressure claw assembly by setting a pneumatic mechanism, thereby achieving adjustment of the opening and closing of the intake valve plate. The device can use compressed air as the driving force, which is lower in cost and more economical than the existing hydraulic adjustment structure, and is safe and reliable; the pneumatic mechanism is simple to process and manufacture, and easy to install and maintain. By controlling the amount of air supplied, the operation of the pneumatic mechanism can be controlled, realizing automated and intelligent control, which has outstanding economic benefits and energy-saving effects. Attached Figure Description

[0031] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of a reciprocating compressor cylinder. Figure 2 This is a schematic diagram of the intake valve used in the cylinder of a reciprocating compressor. Figure 3 A schematic diagram of a device for adjusting the discharge capacity of a reciprocating compressor according to an embodiment of the present invention is shown.

[0032] List of reference numerals in the attached diagram: A1, Cylinder block; A2, Piston; A3, Piston rod; V1, Intake valve; V2, Exhaust valve; V3, Intake valve; V4, Exhaust valve; V10, Valve seat; V20, Valve cover; V30, Valve plate; V40, Wave spring plate; V50, Closing spring; V60, Locking nut.

[0033] 100. Pneumatic mechanism; 110. Diaphragm box; 111. Bottom shell; 112. Top cover; 113. Air chamber; 113a. Working chamber; 113b. Balance chamber; 120. Diaphragm; 121. Central part; 122. Peripheral part; 130. Valve stem; 140. Diaphragm reset component; 200. Support mechanism; 210. Valve hole cover; 220. Support flange; 230. Seal; 300. Claw assembly; 310. Claw seat; 311. Receiving groove; 312. Claw; 320. Claw reset spring; 400. Leakage detection component; 500. Air supply mechanism; 510. Air supply pipeline; 520. Control valve; A. Air inlet; B. Air outlet; C. Exhaust port. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] The terms "comprising" and "having," and any variations thereof, used in the specification and accompanying drawings of this invention are intended to cover non-exclusive inclusion; the terms "first," "second," etc., used in the specification, claims, or accompanying drawings of this invention are used to distinguish different objects, not to describe a particular order. "A plurality of" means two or more, unless otherwise explicitly specified.

[0036] In the description of this invention and the above-described drawings, when an element is referred to as "fixed to," "mounted to," "set on," or "connected to" another element, it can be located directly or indirectly on that other element. For example, when an element is referred to as "connected to" another element, it can be directly or indirectly connected to that other element.

[0037] Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0038] Figure 1 A schematic diagram of a reciprocating compressor cylinder is shown. The cylinder includes components such as a cylinder body A1, a piston A2, and a piston rod A3. The cylinder body A1 has an intake valve V1 and an exhaust valve V2 on the side near the cylinder head, and an intake valve V3 and an exhaust valve V4 on the side near the crankshaft. The reciprocating compressor relies on the reciprocating motion of the piston A2 inside the cylinder to draw in gas through the intake valve V1 or V3 at the top of the cylinder and to discharge gas through the exhaust valve V2 or V4 at the bottom of the piston.

[0039] The working cycle of a reciprocating compressor can be divided into four processes: expansion, intake, compression, and exhaust. A closed space is formed by the cylinder, piston, and the cylinder end face or cylinder head. As the piston moves back and forth within the cylinder, this closed space changes size. When the space increases, gas from the intake pipe flows into the cylinder through the intake valve. When the space decreases, gas from the cylinder flows out through the exhaust pipe. Because the gas pressure in the exhaust pipe is high and the volume occupied by a unit weight of gas is small, under the control of the intake and exhaust valves, the gas in the cylinder can only be discharged outwards through the exhaust valve. Thus, the movement of the piston can compress the gas to a very high pressure.

[0040] Reciprocating compressors typically use double-acting cylinders, where both ends of the cylinder can form a closed space with the piston. When the piston moves from the point closest to the cylinder head (this point is called the outer dead center), Figure 1 As the piston (located near the left end of the cylinder) moves towards the crankshaft, the enclosed space at one end of the cylinder head (also known as the cylinder head side) increases, allowing air to be drawn in through the intake valve V1. Conversely, the enclosed space at the crankshaft end decreases, allowing air to be exhausted through the exhaust valve V4. At one end of the cylinder head, there is a certain gap between the piston and the cylinder head, meaning some gas always remains inside the cylinder during exhaust and cannot be expelled. When the piston moves from outer dead center towards the crankshaft, the gas remaining in the cylinder expands due to the reduced pressure. This expansion reduces the intake volume, requiring piston A2 to move a longer distance before it can begin intake.

[0041] When the crankshaft rotates 180 degrees, piston A2 moves from the outer dead center to a position close to the crankshaft (this position is called the inner dead center). Figure 1 (Position close to the right end of the cylinder) When the piston A2 moves from the inner dead center to the outer dead center, the enclosed space on the side near the cylinder head decreases, the gas will be compressed and the pressure will increase. When the piston A2 moves a certain distance, the enclosed space on the side near the cylinder head becomes small enough that the pressure of the gas in the cylinder is greater than the pressure in the exhaust pipe, the exhaust valve V2 opens, and the compressor exhausts gas to the outside.

[0042] For multi-stage compressors, the gas discharged from the previous stage is cooled and then sent to the next stage for compression. The gas discharged from the last stage is cooled and then output or directly output to provide compressed gas to users or downstream devices.

[0043] Figure 2 A schematic diagram of the intake valve for a reciprocating compressor cylinder is shown. The intake valve mainly includes a valve seat V10, a valve cover V20 (also known as a "lift limiter"), a valve plate V30, a wave spring plate V40, a closing spring V50, and a locking nut V60.

[0044] The valve seat V10 is the main part of the intake valve, and the valve seat V10 has an intake channel that is controlled by the valve plate V30.

[0045] The valve cover V20 (also known as the lift limiter) is often designed with concentric bosses. These bosses guide the valve plate V30, ensuring that it does not tilt during lifting and lowering. In addition, the valve cover V20 often serves as a spring support. The valve cover V20 also limits the maximum lift of the valve plate V30, preventing it from rising excessively and being damaged during opening. By adjusting the position of the valve cover V20, the opening degree of the valve plate V30 can be controlled, thus affecting the intake air volume.

[0046] Valve plate V30 is a crucial component for controlling the opening and closing of the intake passage. Under the influence of the pressure difference between the inside and outside of the cylinder, valve plate V30 automatically opens and closes, enabling the intake and cut-off of gas.

[0047] Wave spring plate V40 is used to provide additional elastic support or cushioning to reduce the impact of valve plate V30 on valve cover V20 during opening and closing.

[0048] The closing spring V50 is an important component in the intake valve used to assist the valve plate V30 in closing. It provides sufficient elasticity to overcome the pressure difference and friction on both sides of the valve plate V30, ensuring that the valve plate V30 can close in time when the pressure in the cylinder increases.

[0049] The V60 lock nut is used to secure the various components of the intake valve together as a single unit. It ensures that the intake valve components will not loosen or fall off during compressor operation.

[0050] The intake valve of a reciprocating compressor cylinder operates based on the pressure difference between the inside and outside of the cylinder. When the piston moves, increasing the volume within the cylinder and decreasing the pressure, the pressure difference increases. When this pressure difference is sufficient to overcome the force of the closing spring V50, the valve plate V30 of the intake valve moves away from the valve seat V10, allowing external gas to enter the cylinder through the intake passage in the valve body. As gas continues to flow in, the pressure inside the cylinder gradually increases. When the pressure reaches a certain level, the valve plate V30 closes under the combined action of the spring force of the closing spring V50 and the thrust of the airflow, preventing further gas flow.

[0051] One objective of this invention is to provide a device for adjusting the discharge capacity of a reciprocating compressor. The following description, in conjunction with the accompanying drawings and specific embodiments, exemplifies some structures of the device for adjusting the discharge capacity of a reciprocating compressor according to this invention. Figure 3 As shown, the device generally includes a pneumatic mechanism 100, a support mechanism 200, and a pressure claw assembly 300.

[0052] The pneumatic mechanism 100 serves as an actuator to move the pressure claw assembly 300 up and down. The pneumatic mechanism 100 generally includes a diaphragm 110, a diaphragm 120, a valve stem 130, and a diaphragm reset component 140.

[0053] The diaphragm box 110 can be assembled from a bottom shell 111 and a top cover 112. The bottom shell 111 may have a recessed bottom wall and a first flange extending horizontally around the periphery of the bottom wall. The top cover 112 may have an upwardly convex top wall and a second flange extending horizontally around the periphery of the top wall. The first flange and the second flange can be mated and fastened together using bolts or other fasteners. The bottom wall and the top wall enclose a sealed air cavity 113.

[0054] A diaphragm 120 is disposed within the gas chamber 113, dividing the gas chamber 113 into two independent working chambers 113a and balancing chambers 113b. The working chamber 113a is defined by a top wall and the diaphragm 120, while the balancing chamber 113b is defined by a bottom wall and the diaphragm 120. The edge of the diaphragm 120 can be sandwiched between and fixed to a first flange and a second flange. The diaphragm 120 may include a relatively rigid central portion 121 and a resilient peripheral portion 122. The central portion 121 provides the necessary rigidity for mounting components such as the valve stem 130 and the diaphragm reset component 140, while the peripheral portion 122 provides the necessary flexibility for the deformation and movement of the diaphragm. For example, two support plates can be mounted on the central portion 121 of the diaphragm 120, with the flexible portion of the diaphragm 120 sandwiched between the two support plates. The diaphragm 120 can change position according to changes in the pressure difference between the working chamber 113a and the balancing chamber 113b. The working chamber 113a is connected to an external air supply line, which allows the internal air pressure to be changed.

[0055] The valve stem 130 is an intermediate member that transmits the displacement of the diaphragm 120 to the pressure claw assembly 300. The first part of the valve stem 130 (the upper part in the figure) is inserted into the balance chamber 113b, and its top end is connected to the center portion 121 of the diaphragm 120. The second part of the valve stem 130 extends beyond the diaphragm box 110 to apply pressure to the pressure claw assembly 300 to move it downward.

[0056] A diaphragm reset component 140 is connected to the diaphragm 120 to move the diaphragm 120 to an initial position when the pressure difference between the working chamber 113a and the balance chamber 113b meets a predetermined condition. In some embodiments, the diaphragm reset component 140 is a spring disposed in the balance chamber 113b, such as, but not limited to, a helical spring. The spring may be sleeved on a first portion of the valve stem 130, with the upper end of the spring abutting against the center portion 121 of the diaphragm 120 and the lower end of the spring abutting against the inner surface of the bottom wall of the diaphragm box 110.

[0057] The working chamber 113a is connected to an external air supply line, allowing the internal air pressure to be changed. When the air pressure in the working chamber 113a is greater than a predetermined value than the air pressure in the balance chamber 113b, the diaphragm 120 moves toward the bottom wall under the action of the pressure difference, simultaneously causing the valve stem 130 to move downward. Conversely, when the air pressure in the working chamber 113a drops to a certain condition, the pressure difference decreases, and the diaphragm 120 moves toward the top wall under the action of the diaphragm reset component 140, returning to its initial position, simultaneously causing the valve stem 130 to move upward, no longer applying pressure to the pressure claw assembly 300.

[0058] A support mechanism 200 is used to support the pneumatic mechanism 100 on the outer wall of the cylinder of the reciprocating compressor. For this purpose, the support mechanism is connected to the outside of the diaphragm box 110, specifically located below the bottom wall of the diaphragm box 110. In a specific embodiment, the support mechanism 200 includes a valve port cover 210 and a support flange 220. The valve port cover 210 is used to close a valve port on the cylinder wall of the reciprocating compressor for installing an intake valve. The valve port cover 210 can be disc-shaped and fixedly installed on the cylinder wall. The support flange 220 is disposed between the diaphragm box 110 and the valve port cover 210. The support flange 220 may include an integrally formed base plate and a sleeve. The base plate can be fixedly installed on the valve port cover 210 using fasteners, and the sleeve extends upward from the base plate to the bottom wall of the diaphragm box 110. The valve hole cover 210 may have a first through hole at its center, and the support flange 220 may have a second through hole at its center. The first through hole and the second through hole are axially aligned, and the second part of the valve stem 130 extends through the first through hole and the second through hole.

[0059] The pressure claw assembly 300 generally includes a pressure claw seat 310, which has a receiving groove 311 for accommodating the top component (e.g., a lock nut V60) of the intake valve of the reciprocating compressor. The end of the pressure claw seat 310 has pressure claws 312 that can be inserted into the intake passage of the intake valve. The end of the pressure claw seat 310 may have multiple pressure claws 312, which are evenly distributed circumferentially. When the valve stem 130 moves downward with the diaphragm 120, the lower end of the valve stem 130 moves to contact the top wall of the pressure claw seat 310. As the valve stem 130 continues to move downward, it applies downward pressure to the pressure claw seat 310, causing the pressure claws 312 to insert into the intake valve V1 through the intake passage and press down on the valve plate V30 of the intake valve V1, disengaging the valve plate V30 from its closed intake passage position, thereby opening the intake valve V1.

[0060] In some embodiments, the pressure claw assembly 300 further includes a pressure claw reset component, which may specifically be a pressure claw reset spring 320. The pressure claw reset spring 320 is disposed in the receiving groove 311. In use, the lower end of the pressure claw reset spring 320 is supported on the top component of the intake valve, and the upper end of the pressure claw reset spring 320 is fixedly connected to the inner surface of the top wall of the pressure claw seat 310. When the valve stem 130 moves away from the pressure claw assembly 300, the restoring force of the pressure claw reset spring 320 causes the pressure claw 312 to move upward and no longer applies pressure to the valve plate V30.

[0061] In some embodiments, the diaphragm 120 switches between an initial position and a depressed position as the pressure difference between the working chamber 113a and the balance chamber 113b changes. In the initial position, the central portion 121 of the diaphragm 120 is far from the bottom wall of the diaphragm box 110, and the diaphragm 120 is in its balanced position due to the pressure difference between the working chamber 113a and the balance chamber 113b, as well as the pushing action of the diaphragm reset component 140. A gap exists between the end of the second portion of the valve stem 130 and the top of the pressure claw seat 310, and the pressure claw 312 does not apply pressure to the valve plate V30 of the intake valve V1, causing the valve plate V30 of the intake valve V1 to be in the closed position, sealing the intake passage. When in the depressed position, because more gas is filled into the working chamber 113a, the pressure in the working chamber 113a increases. The pressure difference between the working chamber 113a and the balance chamber 113b causes the diaphragm 120 to move downward. The central part 121 of the diaphragm 120 is close to the bottom wall of the diaphragm box 110. When the diaphragm 120 moves downward, it drives the valve stem 130 to move downward. The end of the second part of the valve stem 130 presses against the top of the pressure claw seat 310 to cause the pressure claw 312 to press the valve plate V30 down to the open position that connects the intake passage with the inside of the cylinder of the reciprocating compressor, thus keeping the intake valve V1 in the normally open state.

[0062] Optionally, in some embodiments, the travel distance between the initial position and the depressed position is set to match the distance the valve plate of the intake valve moves from the closed position to the open position. This travel distance allows the valve plate to open fully without damaging the components of the intake valve, such as preventing excessive compression and deformation of the valve plate. For example, when the travel distance of the valve plate from the closed position to the open position is 3 mm, the travel distance between the initial position and the depressed position can be set to 6 mm. Moreover, in the initial position, there is a gap of approximately 3 mm between the end of the second part of the valve stem 130 and the top of the pressure claw seat 310 to prevent the pressure claw seat 310 from colliding with the bottom of the valve stem 130 when it rebounds. When the diaphragm 120 moves down 3 mm from the initial position, the valve stem 130 begins to contact the top of the pressure claw seat 310. As it continues to move down, the valve stem 130 presses down on the pressure claw seat 310, thereby causing the pressure claw 312 to press down on the valve plate. When the diaphragm 120 moves down 6 mm from the initial position, the valve plate moves down 3 mm, exactly to the fully open position. When the working chamber 113a is vented, the diaphragm 120 moves from the depressed position to the initial position, and moves upward by 6mm. The pressure claw seat 310 moves upward by 3mm back to its original position. Since there is a 3mm gap between the end of the second part of the valve stem 130 and the top of the pressure claw seat 310, the pressure claw seat 310 will not collide with the valve stem 130 when it rebounds, thus avoiding mechanical collision or vibration damage to the components.

[0063] Optionally, in some embodiments, to improve the airtightness of the cylinder of the reciprocating compressor, the gap between the wall of the first through hole of the valve port cover 210 and the surface of the valve stem 130 can be sealed by a sealant 230. For example, sealing packing can be provided in the gap between the two to achieve a seal. Further, the device may also include a leak detection component 400. A detection channel can be opened in the peripheral wall of the support flange 220, which communicates with the second through hole of the support flange 220 and is also connected to a sensor for detecting gas leaks. For example, a combustible gas detector or a pressure sensor can be used. If the gap between the wall of the first through hole and the surface of the valve stem 130 is not completely sealed, resulting in gas leakage, since the first through hole is connected to the second through hole, the combustible gas detector or pressure sensor can detect the fluctuations and changes in the concentration or pressure of the gas flowing into the detection channel as the compressor operates, thereby determining that there is a gas leak. If there is a leaking gas, it indicates that the valve stem sealing packing is leaking, and the machine needs to be shut down for maintenance. If there is no leak, it can continue to be used.

[0064] Optionally, in some embodiments, the device for adjusting the discharge capacity of the reciprocating compressor according to the present invention may further include a gas supply mechanism 500. The gas supply mechanism 500 may include a gas source (not shown), a gas supply line 510, and a control valve 520. The gas supply line 510 connects the working chamber 113a to the gas source, and the control valve 520 is disposed in the gas supply line 510. For example, in some embodiments, the control valve 520 is a two-position three-way solenoid valve. The first gas port (inlet A shown) of the solenoid valve is connected to the gas source, the second gas port (outlet B shown) is connected to the working chamber 113a, and the third gas port (outlet C shown) is connected to the external environment or atmosphere. The solenoid valve can be controlled and switched between energized and de-energized states. When the solenoid valve is energized, the gas source is connected to the working chamber 113a, and gas can flow from the gas source into the working chamber 113a. When the solenoid valve is de-energized, the working chamber 113a is connected to the external environment or atmosphere, and the gas in the working chamber 113a is discharged into the atmosphere. The voltage of the solenoid valve can be 24V, which is a safe voltage and will not cause electric shock accidents.

[0065] Another object of the present invention is to provide a system for regulating the discharge capacity of a reciprocating compressor. The system includes a pressure sensor installed in the first-stage cylinder of the reciprocating compressor for detecting inlet pressure, a device for regulating the discharge capacity of the reciprocating compressor as described in any of the above embodiments, and a controller. The controller stores an inlet pressure setpoint for switching the inlet valve of the reciprocating compressor to the open state. The controller receives information detected by the pressure sensor and controls the operation of the device for regulating the discharge capacity of the reciprocating compressor based on a comparison of this information with the inlet pressure setpoint.

[0066] In one specific embodiment, the controller may employ a DCS (Distributed Control System). The DCS system determines whether to inflate or vent the working chamber 113a based on a comparison between the detected inlet air pressure information and the inlet pressure setpoint.

[0067] Optionally, in some embodiments, the device for adjusting the discharge volume of the reciprocating compressor is installed on the intake valve on the cylinder head side of the first-stage cylinder of the reciprocating compressor.

[0068] Optionally, in some embodiments, the system may further include a human-machine interface (HMI). The HMI may be, for example, a touchscreen or buttons, providing the operator with manual and automatic control options. When the manual control option is selected, the operator manually controls the inflation / deflation operation of the pneumatic mechanism. When the automatic control option is selected, the controller automatically controls the operation of the pneumatic mechanism based on a comparison of detected air pressure information with the inlet pressure setpoint. By providing "manual" and "automatic" modes, the operator can flexibly switch system modes as needed, improving operational efficiency and system safety.

[0069] When the automatic control option is selected, the controller is configured to perform the following operations: in response to the detected inlet air pressure being lower than the inlet pressure set value, the external air supply line is activated to inflate the working chamber of the pneumatic mechanism to move the valve plate of the inlet valve to the open position; in response to the detected inlet air pressure being not lower than the inlet pressure set value, the working chamber of the pneumatic mechanism is controlled to exhaust air to move the valve plate of the inlet valve to the closed position.

[0070] Optionally, in some embodiments, when the device for adjusting the discharge volume of the reciprocating compressor is equipped with a two-position three-way solenoid valve, the controller controls the operation of the pneumatic mechanism by controlling the energization and de-energization of the solenoid valve.

[0071] Optionally, in some embodiments, the system may further include a timer that counts and records the time when the reciprocating compressor is running and the solenoid valve is energized, and the controller calculates the cumulative energy savings of the reciprocating compressor based on the recorded cumulative duration.

[0072] The following example illustrates the operation of the system using a two-position three-way solenoid valve, but the present invention is not limited thereto.

[0073] In this example, the device for adjusting the discharge volume of the reciprocating compressor is used in conjunction with the intake valve on the cylinder head side of the first-stage cylinder. Pneumatic control logic, programmed into the DCS system, outputs start or stop signals via a DO card. For instance, when the inlet pressure detected by the pressure sensor on the first-stage cylinder is lower than the inlet pressure setpoint stored in the controller (e.g., 0.8 MPa), the DCS system outputs a start signal; when the detected inlet pressure is higher than 0.8 MPa, the DCS system outputs a stop signal. The specific value of the compressor's first-stage cylinder inlet pressure setpoint can be modified by the operator according to production needs.

[0074] The 24V power supply of the two-position three-way solenoid valve is connected to the I / O card of the DCS system's digital output (DO) via an instrument cable. The DCS system outputs a start or stop signal according to the control logic, and correspondingly outputs or stops outputting 24V voltage on the DO card, thereby controlling the two-position three-way solenoid valve to be energized or de-energized, thus achieving the purpose of controlling the gas supply to the pneumatic mechanism.

[0075] Specifically, the gas supplied by the gas source (e.g., compressed air) enters the two-position three-way solenoid valve through the inlet A. When the digital output (DO) card outputs 24V, the two-position three-way solenoid valve is energized, and the compressed air exits from the outlet B of the two-position three-way solenoid valve and enters the working chamber 113a. The internal air pressure of the working chamber 113a increases, pressing down on the diaphragm 120 in the chamber. The diaphragm 120 drives the valve stem 130 to move downward, compressing the diaphragm reset component 140 below the diaphragm 120. The downward movement of the valve stem 130 presses down on the pressure claw seat 310, and the pressure claw 312 presses down on the valve plate V30 of the reciprocating compressor intake valve V1. The reciprocating compressor intake valve enters the normally open state, and the reciprocating compressor starts the single-acting working mode, with a discharge volume of 60% of the full load of the reciprocating compressor. When the digital output (DO) card stops outputting 24V voltage, the two-position three-way solenoid valve is de-energized, and gas is no longer introduced into the inlet A of the two-position three-way solenoid valve. The residual gas in the working chamber 113a is discharged through the exhaust port C of the two-position three-way solenoid valve, and the internal air pressure of the working chamber 113a decreases. The diaphragm 120 rebounds upward under the rebound force of the diaphragm reset component 140, which drives the valve stem 130 to move upward. At the same time, the pressure claw reset spring in the pressure claw seat 310 rebounds upward to release the valve plate. The valve plate moves upward to the closed position under the rebound force of the closing spring. The reciprocating compressor intake valve enters the normal working state, the reciprocating compressor starts the double-acting working mode, and the exhaust volume is restored to the full load state.

[0076] The reciprocating compressor automatically and intermittently switches between double-acting and single-acting working modes based on the comparison between the set value and the measured value of the compressor's primary inlet pressure. The discharge volume of the reciprocating compressor fluctuates between 60% and 100%, thereby realizing the discharge volume regulation function of the reciprocating compressor.

[0077] A timer function can be developed on the DCS system. When the reciprocating compressor is running and the two-position three-way solenoid valve is energized, the first-stage cylinder of the reciprocating compressor is in single-acting operation, and the timer starts automatically to accumulate the time, calculating the cumulative single-acting operating time of the first-stage cylinder. When the reciprocating compressor is running and the two-position three-way solenoid valve is de-energized, the first-stage cylinder is in double-acting operation, and the timer stops accumulating the time. By multiplying the accumulated time by the hourly electricity savings, the cumulative electricity cost savings of the reciprocating compressor can be calculated. The timer function facilitates management and technical personnel in calculating the cumulative electricity cost savings of the reciprocating compressor.

[0078] Another object of the present invention is to provide a method for adjusting the discharge capacity of a reciprocating compressor using the system described in any of the above embodiments, the method comprising the following steps: The inlet pressure setpoint is stored in the controller. The inlet pressure setpoint is used as the threshold for switching the intake valve of the first stage cylinder of the reciprocating compressor to the normally open state. The inlet air pressure of the first-stage cylinder detected by the air pressure sensor is compared with the inlet pressure set value; In response to the detected air pressure being lower than the inlet pressure set value, air is injected into the working chamber of the pneumatic mechanism to move the valve plate of the inlet valve to the open position; In response to the detected air pressure not being lower than the inlet pressure set value, the working chamber is controlled to exhaust air, so that the valve plate of the intake valve moves to the closed position.

[0079] The device of the present invention uses a pneumatic mechanism to adjust the position of the pressure claw assembly, thereby adjusting the opening and closing of the air intake valve plate. The pneumatic mechanism can use compressed air as the driving force. Compared with the existing hydraulic adjustment structure, it is lower in cost, more economical, and safer and more reliable. The device is simple to manufacture, easy to install and maintain. By controlling the amount of air supplied, the operation of the pneumatic mechanism can be controlled, achieving automated and intelligent control.

[0080] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A device for adjusting the discharge capacity of a reciprocating compressor, characterized in that, include: A pneumatic mechanism includes a diaphragm, a diaphragm, a valve stem, and a diaphragm reset component. The diaphragm has an air chamber, and the diaphragm is disposed within the air chamber. The diaphragm divides the air chamber into an independent working chamber and a balance chamber, and changes position according to the pressure difference between the working chamber and the balance chamber. The working chamber is connected to an external air supply line. A first part of the valve stem is inserted into the balance chamber and connected to the diaphragm, and a second part of the valve stem extends outside the diaphragm. The diaphragm reset component is connected to the diaphragm to move the diaphragm to an initial position when the pressure difference between the working chamber and the balance chamber meets a predetermined condition. A support mechanism is connected to the outside of the diaphragm box to support the pneumatic mechanism on the outer wall of the cylinder of the reciprocating compressor, and a second portion of the valve stem extends through the body of the support mechanism; The pressure claw assembly includes a pressure claw seat, which has a receiving groove for accommodating the top component of the intake valve of the reciprocating compressor. The end of the pressure claw seat is provided with a pressure claw, which can be inserted into the intake passage of the intake valve. Under the downward pressure of the second part of the valve stem, the pressure claw seat can push open the valve plate of the intake valve to open the intake valve.

2. The device for adjusting the discharge capacity of a reciprocating compressor according to claim 1, characterized in that, The diaphragm is switchable between the initial position and the depressed position. In the initial position, there is a first gap between the end of the second part of the valve stem and the top of the pressure claw seat, and the pressure claw does not apply pressure to the valve plate, so that the valve plate is in the closed position that closes the air intake passage. In the depressed position, the end of the second part of the valve stem presses against the top of the pressure claw seat to cause the pressure claw to press the valve plate down to the open position that connects the air intake passage with the inside of the cylinder of the reciprocating compressor.

3. The device for adjusting the discharge capacity of a reciprocating compressor according to claim 2, characterized in that, The travel distance between the initial position and the depressed position matches the distance the valve plate moves from the closed position to the open position.

4. The device for adjusting the discharge capacity of a reciprocating compressor according to claim 2, characterized in that, The pressure claw assembly further includes a pressure claw reset component, which is disposed in the receiving groove and causes the pressure claw seat to spring back after the valve stem disengages from the pressure claw seat. The first gap is set so that the pressure claw seat does not collide with the end of the valve stem during the springback.

5. The device for adjusting the discharge capacity of a reciprocating compressor according to claim 1, characterized in that, The diaphragm reset component is a spring disposed in the balance chamber, the spring being sleeved on the valve stem with its two ends abutting against the diaphragm and the diaphragm box, respectively.

6. The device for adjusting the discharge capacity of a reciprocating compressor according to claim 1, characterized in that, The support mechanism includes a valve hole cover and a support flange. The valve hole cover is used to close the valve hole on the cylinder wall of the reciprocating compressor for installing the intake valve. The support flange is disposed between the diaphragm and the valve hole cover.

7. The device for adjusting the discharge capacity of a reciprocating compressor according to claim 6, characterized in that, The valve hole cover has a first through hole at its center, the support flange has a second through hole at its center, and the second part of the valve stem extends through the first through hole and the second through hole.

8. The device for adjusting the discharge capacity of a reciprocating compressor according to claim 7, characterized in that, The gap between the wall of the first through hole and the surface of the valve stem is sealed with a sealant.

9. The device for adjusting the discharge capacity of a reciprocating compressor according to claim 8, characterized in that, The device also includes a leak detection component. A detection channel is provided in the peripheral wall of the supporting flange. The detection channel is connected to the second through hole and is also connected to a sensor for detecting gas leaks.

10. The device for adjusting the discharge capacity of a reciprocating compressor according to claim 1, characterized in that, The device also includes a gas supply mechanism, which includes a gas source, a gas supply pipeline, and a control valve. The gas supply pipeline connects the working chamber to the gas source, and the control valve is disposed in the gas supply pipeline.

11. The device for adjusting the discharge capacity of a reciprocating compressor according to claim 10, characterized in that, The control valve is a two-position three-way solenoid valve. The first gas port of the solenoid valve is connected to the gas source, the second gas port is connected to the working chamber, and the third gas port is connected to the external environment.

12. The device for adjusting the discharge capacity of a reciprocating compressor according to claim 11, characterized in that, The solenoid valve is controlled to switch between a first state and a second state, wherein in the first state, the solenoid valve is energized to connect the gas source to the working chamber, and in the second state, the solenoid valve is de-energized to connect the working chamber to the external environment.

13. A system for regulating the discharge capacity of a reciprocating compressor, characterized in that, include: A pressure sensor is installed in the first-stage cylinder of the reciprocating compressor to detect the inlet pressure; Device for adjusting the discharge volume of a reciprocating compressor according to any one of claims 1-12; The controller receives information detected by the pressure sensor and controls the operation of the device for adjusting the discharge volume of the reciprocating compressor based on a comparison of the information with an inlet pressure setpoint stored in the controller.

14. The system for adjusting the discharge capacity of a reciprocating compressor according to claim 13, characterized in that, The device for adjusting the discharge volume of the reciprocating compressor is installed on the intake valve on the cylinder head side of the first-stage cylinder.

15. The system for adjusting the discharge capacity of a reciprocating compressor according to claim 13, characterized in that, The system also includes a human-machine interface device that provides the operator with manual control options and automatic control options. When the manual control option is selected, the operator controls the operation of the device for adjusting the discharge capacity of the reciprocating compressor. When the automatic control option is selected, the controller controls the operation of the device for adjusting the discharge capacity of the reciprocating compressor based on a comparison between the air pressure information and the inlet pressure setpoint.

16. The system for adjusting the discharge capacity of a reciprocating compressor according to claim 15, characterized in that, The controller is configured to perform the following operations when the automatic control option is selected: When the detected inlet air pressure is lower than the inlet pressure set value, the external air supply line is activated to pressurize the working chamber of the pneumatic mechanism to move the valve plate of the inlet valve to the open position. When the detected inlet air pressure is not lower than the inlet pressure set value, the working chamber of the pneumatic mechanism is controlled to exhaust air, so that the valve plate of the inlet valve moves to the closed position.

17. The system for adjusting the discharge capacity of a reciprocating compressor according to claim 16, characterized in that, When the device for adjusting the discharge volume of the reciprocating compressor is equipped with a two-position three-way solenoid valve, the controller controls the operation of the pneumatic mechanism by controlling the energization and de-energization of the solenoid valve.

18. The system for adjusting the discharge capacity of a reciprocating compressor according to claim 17, characterized in that, The system also includes a timer that counts and records the time when the reciprocating compressor is running and the solenoid valve is energized. The controller calculates the cumulative energy savings of the reciprocating compressor based on the recorded cumulative duration.

19. A method for adjusting the discharge capacity of a reciprocating compressor using the system as described in any one of claims 13-18, characterized in that, Includes the following steps: The inlet pressure setpoint is stored in the controller. The inlet pressure setpoint is used as the threshold for switching the intake valve of the first stage cylinder of the reciprocating compressor to the normally open state. The inlet air pressure of the first-stage cylinder detected by the air pressure sensor is compared with the inlet pressure set value; In response to the detected air pressure being lower than the inlet pressure set value, air is injected into the working chamber of the pneumatic mechanism to move the valve plate of the inlet valve to the open position; In response to the detected air pressure not being lower than the inlet pressure set value, the working chamber is controlled to exhaust air, so that the valve plate of the intake valve moves to the closed position.

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