Multi-stage compression gas compression system

Abstract

The utility model discloses a multi-stage compression gas compression system which comprises a hydraulic driving unit with fixed displacement, a multi-stage compression cylinder, a gas storage device, a gas pressure detection unit and a control unit, the multi-stage compression cylinder comprises a plurality of compression cylinders which are sequentially connected in series from the first stage to the last stage through gas conveying pipelines. The signal output end of the air pressure detection unit is connected with the signal input end of the control unit. The air pressure detection unit is used for detecting air pressure signals of the multi-stage compression cylinder and sending the air pressure signals to the control unit. And the control unit is used for controlling the working states of the other stages of compression cylinders except the first-stage compression cylinder in the multi-stage compression cylinders according to the air pressure signal, so that the other stages of compression cylinders except the first-stage compression cylinder in the multi-stage compression cylinders are put into compression work or quit compression work. According to the utility model, the cost and the control complexity of the gas compression system can be reduced, and the efficiency improvement and consumption reduction of the gas compression system can be realized.

Description

Technical Field

[0001] This utility model relates to the technical field of gas unloading facilities for gas stations, and in particular to a multi-stage gas compression system. Background Technology

[0002] Currently, gas stations typically need to compress gaseous fuels such as hydrogen and CNG (compressed natural gas) transported by long-tube trailers through a gas compression system before storing them in a gas storage device.

[0003] like Figure 1 The diagram shows the structure of an existing multi-stage gas compression system. 10 is the first-stage compression cylinder, 20 is the second-stage compression cylinder (some gas compression systems currently use third-stage or higher compression cylinders), 30 is the hydraulic drive unit, 40 is the inlet pipeline connecting the hydraulic drive unit to the oil side of each compression cylinder, 50 is the return pipeline connecting the hydraulic drive unit to the oil side of each compression cylinder, and 60 is a hydraulic directional valve used to switch the connection between the inlet and return pipelines and the two oil ports of each compression cylinder.

[0004] from Figure 1 As can be seen, in a multi-stage gas compression system, the compression cylinders at each stage are connected in parallel in the hydraulic circuit, meaning that both oil ports of each compression cylinder are connected to the hydraulic directional valve, and hydraulic oil pressure is provided to each compression cylinder through the same inlet pipe; the compression cylinders at each stage are connected in series in the gas circuit, meaning that the gas discharged from the exhaust port of the previous stage compression cylinder enters the inlet port of the next stage compression cylinder. However, in order to allow each compression cylinder to directly fill the gas storage device,

[0005] Figure 1 In the multi-stage gas compression system shown, the hydraulic drive unit uses an electric motor to drive a booster pump to supply hydraulic oil to each stage of the compression cylinder. The hydraulic oil displacement can be a fixed displacement (the booster pump is a fixed displacement pump and the electric motor is a fixed frequency motor) or a variable displacement (the booster pump is a variable displacement pump and the electric motor is a fixed frequency motor, or the booster pump is a fixed displacement pump and the electric motor is a variable frequency motor).

[0006] When the hydraulic drive unit adopts a variable displacement scheme, although the hydraulic oil displacement can be automatically adjusted according to needs or actual working conditions to achieve efficiency improvement and consumption reduction, the variable pump and variable frequency motor are expensive, which increases the overall cost of the gas compression system. Moreover, the control of the gas compression system using a variable pump or variable frequency motor is complicated.

[0007] When the hydraulic drive unit adopts a fixed displacement scheme, Figure 1In the shown prior art gas compression system scheme, in order to ensure that the gas bottle can reach the inflation pressure when the gas pressure in the long tube trailer is low, all the compression cylinders work at the same time during the system operation to compress the gas delivered by the long tube trailer in multiple stages.

[0008] However, since the pressure of the gas delivered by the long tube trailer is initially high, the inflation pressure of the gas storage device can be reached after compression by the first stage compression cylinder or the first few stages of compression cylinders, and in this stage, although the last stage compression cylinder or the last few stages of compression cylinders are also working under the action of the hydraulic oil pressure, the exhaust port pressure of the second last stage compression cylinder or the other stages of compression cylinders before the second last stage is already able to reach the inflation pressure of the gas storage device, and the gas compressed by the second last stage compression cylinder or the other stages of compression cylinders before the second last stage is directly supplied to the gas storage device through the air pipe connected between the exhaust port of the second last stage compression cylinder or the other stages of compression cylinders before the second last stage and the exhaust port of the next stage compression cylinder.

[0009] Therefore, how to reduce the cost and control complexity of the gas compression system while realizing the efficiency improvement and energy saving of the gas compression system is a problem to be solved in the field. SUMMARY

[0010] To solve the above technical problems, the utility model provides a kind of multistage compression gas compression system, can reduce the cost and control complexity of gas compression system while realizing the efficiency improvement and energy saving of gas compression system.

[0011] To achieve the above purpose, the utility model provides the following technical scheme:

[0012] A kind of multistage compression gas compression system includes fixed displacement hydraulic drive unit, multistage compression cylinder, gas storage device, gas pressure detection unit and control unit, wherein,

[0013] The multistage compression cylinder includes multiple compression cylinders connected in series by gas delivery pipe from first stage to last stage, the gas inlet of the first stage compression cylinder in the multistage compression cylinder is connected with long tube trailer by gas inlet pipe, and the gas outlet of the last stage compression cylinder in the multistage compression cylinder is connected with the gas storage device by gas outlet pipe;

[0014] The signal output end of the gas pressure detection unit is connected with the signal input end of the control unit, and the gas pressure detection unit is used for detecting the gas pressure signal of the multi-stage compression cylinder and sending to the control unit.

[0015] The control unit is used for controlling the working state of each stage compression cylinder except the first stage compression cylinder in the multi-stage compression cylinder according to the gas pressure signal, so as to put each stage compression cylinder except the first stage compression cylinder in the multi-stage compression cylinder into compression work or exit from compression work.

[0016] Preferably, the gas pressure detection unit comprises N air inlet pressure sensors which are respectively arranged at the air inlets of each stage compression cylinder except the last stage compression cylinder in the multi-stage compression cylinder,

[0017] Each air inlet pressure sensor is used for detecting the air inlet pressure value P1-PN at the air inlet of each stage compression cylinder except the last stage compression cylinder in the multi-stage compression cylinder, wherein,

[0018] P1 is the air inlet pressure value of the first stage compression cylinder, PN is the air inlet pressure value of the Nth stage compression cylinder, N is a positive integer, and N=M-1, and M represents the total number of stages of the multi-stage compression cylinder.

[0019] Preferably, the control unit comprises a main control module and N control valve groups, wherein,

[0020] The N control valve groups are respectively arranged on the oil side pipeline of each stage compression cylinder except the first stage compression cylinder in the multi-stage compression cylinder, and each control valve group is used for controlling the on-off of the oil pipeline of the corresponding compression cylinder.

[0021] Preferably, the signal output end of the N air inlet pressure sensors is connected with the N signal input ends of the main control module in one-to-one correspondence.

[0022] Preferably, the control valve group is an electric control valve, and the signal input end of the N control valve groups is connected with the N signal output ends of the main control module in one-to-one correspondence.

[0023] Preferably, the main control module comprises N comparators and a threshold storage, the first signal input end of the N comparators is connected with the N air inlet pressure sensors in one-to-one correspondence, the second signal input end of the N comparators is connected with the threshold storage, and the signal output end of the N comparators is connected with the signal input end of the N control valve groups in one-to-one correspondence, wherein,

[0024] The comparator is used for comparing the intake pressure value output by the intake pressure sensor connected thereto with the open valve pressure threshold value stored in the threshold value memory, and outputting corresponding level signals to the control valve group connected thereto according to the comparison result, so as to control the opening or closing of the control valve group through the level signals.

[0025] Preferably, the control valve group is a manual control valve.

[0026] Preferably, the multi-stage compression gas compression system further comprises N switch valve prompt modules, which are arranged on the N control valve groups one by one.

[0027] Preferably, the master control module comprises N comparators and a threshold value memory, the first signal input ends of the N comparators are connected with the N intake pressure sensors one by one, the second signal input ends of the N comparators are connected with the threshold value memory, and the signal output ends of the N comparators are connected with the signal input ends of the N switch valve prompt modules one by one.

[0028] The comparator is used for comparing the intake pressure value output by the intake pressure sensor connected thereto with the open valve pressure threshold value stored in the threshold value memory, and outputting corresponding level signals to the control valve group connected thereto according to the comparison result, so as to control the opening or closing of the control valve group through the level signals.

[0029] Preferably, the control valve group comprises a first control valve for controlling the opening and closing of the oil injection port / oil return port of the corresponding compression cylinder and / or a second control valve for controlling the opening and closing of the oil return port / oil injection port of the corresponding compression cylinder.

[0030] The utility model discloses a kind of multi-stage compression gas compression systems, by setting fixed displacement hydraulic drive unit, multistage compression cylinder, gas storage device, gas pressure detection unit and control unit, the gas pressure signal of multistage compression cylinder is detected by gas pressure detection unit and sent to control unit, the working state of each level compression cylinder except one-stage compression cylinder in multistage compression cylinder is controlled by control unit according to gas pressure signal, to make each level compression cylinder except one-stage compression cylinder in multistage compression cylinder put into compression work or exit compression work, so that the gas pressure in long tube trailer is lower, when the inflation pressure of gas storage device cannot be reached by the compression of part of multistage compression cylinder, make all compression cylinder put into compression work, and when the gas pressure in long tube trailer is higher, the inflation pressure of gas storage device can be reached by the compression of part of multistage compression cylinder, make part or all compression cylinder in each level compression cylinder except one-stage compression cylinder exit compression work, so that the cost and control complexity of gas compression system are reduced, and the efficiency of gas compression system is realized. BRIEF DESCRIPTION OF DRAWINGS

[0031] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of an existing multi-stage gas compression system.

[0033] Figure 2 This is a schematic diagram of the structure of a multi-stage gas compression system in one embodiment of this application;

[0034] Figure 3 for Figure 2 The circuit block diagram of the multi-stage gas compression system is shown.

[0035] Figure 4 This is a schematic diagram of the structure of a multi-stage gas compression system according to another embodiment of this application;

[0036] Figure 5 for Figure 4 The circuit block diagram shown is for a multi-stage gas compression system. Detailed Implementation

[0037] To enable those skilled in the art to better understand the technical solutions of this utility model, the technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0038] In the embodiments provided by this utility model, it should be understood that the disclosed methods and systems can be implemented in other ways. The system embodiments described below are merely illustrative. For example, the division of units and modules is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or modules can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, and can be electrical, mechanical, or other forms.

[0039] In addition, all the functional units in each of the embodiments of the utility model can be integrated in one processor, can be each unit respectively alone as a device, can be two or more than two units integrated in one device, each of the functional units in each of the embodiments of the utility model can adopt the form of realization of hardware, can adopt the form of realization of hardware plus software functional unit.

[0040] Those skilled in the art can understand that all or part of the steps of the following method embodiments can be completed by program instructions and related hardware, the foregoing program instructions can be stored in a computer readable storage medium, and the program instructions are executed to execute the steps of the method embodiments.

[0041] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more features. In the description of the utility model, the meaning of "a plurality of", "several" is two or more than two, unless otherwise explicitly specified.

[0042] As shown in Figures 2-5 The utility model discloses a multistage compression's gas compression system, this system can include fixed displacement hydraulic drive unit 1, multistage compression cylinder 2, gas storage device 3, gas pressure detection unit 4 and control unit 5, wherein,

[0043] Multistage compression cylinder 2 includes a plurality of compression cylinders that are connected in series through gas delivery pipelines from the first stage to the last stage, and the gas inlet of the first stage compression cylinder 21 in the multistage compression cylinder 2 is connected to the long tube trailer 100 through the gas inlet pipeline, and the gas outlet of the last stage compression cylinder in the multistage compression cylinder 2 is connected to the gas storage device 3 through the gas outlet pipeline.

[0044] The signal output end of the gas pressure detection unit 4 is connected to the signal input end of the control unit 5, and the gas pressure detection unit 4 is used to detect the gas pressure signal of the multistage compression cylinder 2 and send it to the control unit 5.

[0045] The control unit 5 is used to control the working state of each stage compression cylinder in the multistage compression cylinder 2 except the first stage compression cylinder 21 according to the gas pressure signal, so that each stage compression cylinder in the multistage compression cylinder 2 except the first stage compression cylinder 21 is put into compression work or withdrawn from compression work.

[0046] The working principle of the multistage compression gas compression system of the embodiment is as follows:

[0047] In the working process of the gas compression system, the gas pressure signals of the multi-stage compression cylinder 2 are detected by the gas pressure detection unit 4 and sent to the control unit 5, and the working states of the compression cylinders other than the first-stage compression cylinder 21 in the multi-stage compression cylinder 2 are controlled by the control unit 5 according to the gas pressure signals, so that the compression cylinders other than the first-stage compression cylinder 21 in the multi-stage compression cylinder 2 are put into or out of compression work, thereby when the gas pressure in the long tube trailer 100 is low and the compression by the partial compression cylinders of the multi-stage compression cylinder 2 cannot reach the inflation pressure of the gas storage device 3, all the compression cylinders are put into compression work, and when the gas pressure in the long tube trailer 100 is high and the compression by the partial compression cylinders of the multi-stage compression cylinder 2 can reach the inflation pressure of the gas storage device 3, part or all of the compression cylinders other than the first-stage compression cylinder 21 are out of compression work, so that the cost and control complexity of the gas compression system are reduced while the efficiency of the gas compression system is improved and the consumption is reduced.

[0048] When the control unit 5 determines that all the compression cylinders of the multi-stage compression cylinder 2 do not need to be put into compression work according to the gas pressure signals collected by the gas pressure detection unit 4, the hydraulic drive unit 1 may not do work when injecting oil into the compression cylinders other than the first-stage compression cylinder 21 in the multi-stage compression cylinder 2, that is, the oil injected by the hydraulic drive unit 1 into the corresponding compression cylinder is not used, at this time, the control unit 5 controls the corresponding compression cylinder in the compression cylinders other than the first-stage compression cylinder 21 in the multi-stage compression cylinder 2 to be not working, so that the oil injected by the hydraulic drive unit 1 into the compression cylinder which should not be injected is injected into other compression cylinders which need to work, under the condition that the oil side volume of each compression cylinder is fixed, since the hydraulic oil displacement of the hydraulic drive system per unit time is certain, increasing the oil injection amount per unit time of the compression cylinder oil side will inevitably increase its reversing frequency, and then increase the overall exhaust volume of the compressor; because the hydraulic drive unit 1 does not make any changes to the existing fixed displacement hydraulic drive scheme, the power consumption of the hydraulic drive unit 1 per unit time is definitely consistent with before, however, since the overall exhaust volume of the gas compression system per unit time is increased and the power consumption is unchanged, the specific energy consumption is bound to be reduced, thereby reducing the operating cost of the gas filling station, so that the cost and control complexity of the gas compression system are reduced while the efficiency of the gas compression system is improved and the consumption is reduced.

[0049] In one embodiment, the gas pressure detection unit 4 includes N gas inlet pressure sensors 41 arranged one by one at the gas inlets of the compression cylinders other than the last-stage compression cylinder in the multi-stage compression cylinder 2,

[0050] Each gas inlet pressure sensor 41 is used to detect the gas inlet pressure value P1-PN at the gas inlet of each compression cylinder other than the last-stage compression cylinder in the multi-stage compression cylinder 2, wherein,

[0051] P1 is the intake pressure value of the first-stage compression cylinder 21, PN is the intake pressure value of the N-stage compression cylinder, N is a positive integer, N=M-1, and M represents the total number of stages of the multi-stage compression cylinder 2.

[0052] By arranging one intake pressure sensor 41 at the intake port of each compression cylinder except the last-stage compression cylinder, the intake pressure of the corresponding compression cylinder is detected, so that the corresponding compression cylinder is controlled to be put into or out of compression work according to the intake pressure of each compression cylinder.

[0053] In an embodiment, the control unit 5 comprises a master control module 51 and N control valve groups 52, which are arranged on the oil side pipeline of each compression cylinder of the multi-stage compression cylinder 2 except the first-stage compression cylinder 21, and each control valve group 52 is used to control the on-off of the oil pipeline of the corresponding compression cylinder.

[0054] By arranging the control valve group 52 on the oil side pipeline of each compression cylinder of the multi-stage compression cylinder 2 except the first-stage compression cylinder 21, and controlling the on-off of the oil pipeline of the corresponding compression cylinder by the control valve group 52, the corresponding compression cylinder is conveniently controlled to be put into or out of compression work.

[0055] In an embodiment, the signal output ends of the N intake pressure sensors 41 are connected to the N signal input ends of the master control module 51 in one-to-one correspondence.

[0056] In this way, each intake pressure sensor 41 can transmit the detected air pressure signal of the corresponding compression cylinder to the corresponding signal input end of the master control module 51, and the master control module 51 can control the working state of each compression cylinder except the first-stage compression cylinder 21 in one-to-one correspondence according to the input air pressure signal of each signal input end.

[0057] As shown in Figure 2 , Figure 3 In an embodiment, the control valve group 52 is an electric control valve, and the signal input ends of the N control valve groups 52 are connected to the N signal output ends of the master control module 51 in one-to-one correspondence.

[0058] In this embodiment, the control valve group 52 is an electric control valve, so that the master control module 51 can control the working state of the corresponding electric control valve according to the air pressure signal of each intake pressure sensor 41, thereby automatically controlling the corresponding compression cylinder to be put into or out of compression work.

[0059] On the basis of the above embodiment, as shown in Figure 3As shown, in one embodiment, the master module 51 comprises N comparators 511 and a threshold value storage 512, the first signal input end of the N comparators 511 is connected with the N air intake pressure sensors 41 one by one, the second signal input end of the N comparators 511 is connected with the threshold value storage 512, and the signal output end of the N comparators 511 is connected with the signal input end of the N control valve groups 52 one by one, wherein,

[0060] The comparator 511 is used to compare the air intake pressure value output by the air intake pressure sensor 41 connected therewith with the open valve pressure threshold value stored in the threshold value storage 512, and output a corresponding level signal to the control valve group 52 connected therewith according to the comparison result, so as to control the control valve group 52 to open or close through the level signal.

[0061] In the embodiment, the master module 51 adopts the comparator 511 and the threshold value storage 512, which has a simpler structure and does not need program control. Each comparator 511 compares the air pressure signal input at the first input end with the threshold pressure input at the second signal input end, and outputs a corresponding level signal to control the control valve group 52 to open or close according to the comparison result.

[0062] Specifically, in the embodiment, when the air pressure signal input at the first input end of the comparator 511 is less than or equal to the threshold pressure input at the second signal input end (indicating that the compression cylinder and the compression cylinders before it cannot reach the charging pressure of the gas storage device 3 after compression), a high level is output to the corresponding control valve group 52 to make it open, connect the oil circuit of the compression cylinder, and put the corresponding compression cylinder into compression work; when the air pressure signal input at the first input end of the comparator 511 is greater than the threshold pressure input at the second signal input end (indicating that the compression cylinder and the compression cylinders before it can reach the charging pressure of the gas storage device 3 after compression), a low level is output to the corresponding control valve group 52 to make it close, cut off the oil circuit of the compression cylinder, and make the corresponding compression cylinder exit the compression work.

[0063] It should be noted that, since the air intake pressure of each compression cylinder basically shows an increasing trend, when the air intake pressure of a certain compression cylinder 21 is higher than the threshold pressure (indicating that the compression cylinder and the compression cylinders before it can reach the charging pressure of the gas storage device 3 after compression), the compression cylinders after the compression cylinder do not put into compression work. For example, when the air intake pressure sensor 41 on the air intake side of the first compression cylinder 21 detects that the air intake pressure at this position is higher than the threshold pressure, the second compression cylinder 22 and the compression cylinders after the second compression cylinder 22 do not put into compression work.

[0064] It should be noted that the threshold pressure is a pressure value pre-set and stored in the threshold value storage 512, which can be obtained through experiments.

[0065] AsFigure 4 , Figure 5 As shown, in one embodiment, the control valve group 52 is a manually controlled valve, and the multi-stage gas compression system also includes N valve switching indicator modules 6, which are respectively arranged on the N control valve groups 52.

[0066] In this embodiment, the control valve group 52 adopts a manual control valve. The user manually controls whether the corresponding compression cylinder is put into operation by the prompt signal of the corresponding valve switch prompt module 6.

[0067] Specifically, the valve switching indicator module 6 can use an audible and visual indicator.

[0068] Based on the previous embodiment, such as Figure 5 As shown, in one embodiment, the main control module 51 includes N comparators 511 and a threshold memory 512. The first signal input terminals of the N comparators 511 are connected one-to-one with the N intake pressure sensors 41, the second signal input terminals of the N comparators 511 are all connected to the threshold memory 512, and the signal output terminals of the N comparators 511 are connected one-to-one with the signal input terminals of the N valve switching indicator modules 6.

[0069] The comparator 511 is used to compare the intake pressure value output by the intake pressure sensor 41 connected to it with the valve opening pressure threshold stored in the threshold memory 512, and output the corresponding level signal to the valve switching prompt module 6 connected to it according to the comparison result, so as to control the valve switching prompt module 6 to output the corresponding prompt signal through the level signal.

[0070] In this embodiment, the main control module 51 uses a comparator 511 and a threshold memory 512, which has a simpler structure and does not require program control. Each comparator 511 compares the air pressure signal input at its first input terminal with the threshold pressure input at its second signal input terminal, and outputs a corresponding level signal according to the comparison result to control the valve prompting module 6 to issue a corresponding prompt signal.

[0071] Specifically, in the embodiment, when the air pressure signal inputted into the first input end of the comparator 511 is less than or equal to the threshold pressure inputted into the second signal input end (indicating that the compression cylinder cannot reach the charging pressure of the air storage device 3 after compression by the previous stage compression cylinder), a high level is outputted to the corresponding switch valve prompting module 6, so that the switch valve prompting module 6 sends out a valve opening prompt (such as a first sound and light prompt signal), prompting the user to open the corresponding control valve group 52 to connect the oil circuit of the compression cylinder, and the corresponding compression cylinder enters the compression work; when the air pressure signal inputted into the first input end of the comparator 511 is greater than the threshold pressure inputted into the second signal input end (indicating that the compression cylinder can reach the charging pressure of the air storage device 3 after compression by the previous stage compression cylinder), a low level is outputted to the corresponding switch valve prompting module 6, so that the switch valve prompting module 6 sends out a valve closing prompt signal (a second sound and light prompt signal different from the first sound and light prompt signal), prompting the user to close the corresponding control valve group 52 to cut off the oil circuit of the compression cylinder, and the corresponding compression cylinder exits the compression work.

[0072] As shown in Figures 2-5 , in one embodiment, the control valve group 52 includes a first control valve 521 for controlling the opening and closing of the oil inlet / outlet port of the corresponding compression cylinder and / or a second control valve 522 for controlling the opening and closing of the oil inlet / outlet port of the corresponding compression cylinder.

[0073] Since each compression cylinder has two oil ports on the oil side, and the oil inlet / outlet state of the two oil ports is constantly switched to control the reversing compression of the compression cylinder, when the first oil port is an oil inlet port, the second oil port is an oil outlet port, and when the first oil port is an oil outlet port, the second oil port is an oil inlet port, therefore, as long as one of the oil ports is closed by the control valve group 52, the oil circuit of the compression cylinder is cut off, therefore, in one embodiment, as shown in Figure 4 , the control valve group 52 can be installed at any oil port of the corresponding compression cylinder (as shown in Figure 4 ). In order to ensure better cutting effect, in one embodiment, as shown in Figure 2 , Figure 3 , in the embodiment, the control valve group 52 preferably uses two control valves, i.e. the first control valve 521 and the second control valve 522 respectively control the opening and closing of the two oil ports of the compression cylinder.

[0074] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method part.

[0075] Those skilled in the art will further realize that the mere conception of the examples described herein is not inducing patentable subject matter, and that each of the examples represent a distinct application of the fundamental principles and unique attributes claimed by the present application. Accordingly, altho ugh the present application has been described in detail with reference to exemplary implementations, it is understood that the application is not limited to those implementations. Instead, the application can be implemented in various environments and with various modifications and changes. Therefore, it is to be understood that the application can be practiced otherwise than specifically described, without departing from the spirit or scope of the application as defined by the appended claims.

[0076] The steps of a method or algorithm described in connection with the examples disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in RAM, flash memory, ROM, electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art

[0077] The above description of disclosed examples is intended to be illustrative and not restrictive. Many modifications of the examples as described can be readily apparent to those having skill in this art, and the principles defined herein can be applied to other examples without departing from the spirit or scope of the description. Thus, the present application is not to be limited to the examples presented but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-stage compression gas compression system, characterized by, The hydraulic drive unit includes a fixed displacement hydraulic drive unit, a multi-stage compression cylinder, an air storage device, an air pressure detection unit, and a control unit, wherein The multi-stage compression cylinder includes a plurality of compression cylinders connected in series through gas delivery pipelines, an air inlet of a first stage compression cylinder of the multi-stage compression cylinder is connected to the long tube trailer through an air inlet pipeline, and an air outlet of a last stage compression cylinder of the multi-stage compression cylinder is connected to the air storage device through an air outlet pipeline. The signal output end of the air pressure detection unit is connected to the signal input end of the control unit, and the air pressure detection unit is used to detect the air pressure signal of the multi-stage compression cylinder and send it to the control unit. The control unit is used to control the working state of each stage compression cylinder of the multi-stage compression cylinder except the first stage compression cylinder according to the air pressure signal, so that each stage compression cylinder of the multi-stage compression cylinder except the first stage compression cylinder is put into or out of compression work.

2. The multi-stage compression gas compression system of claim 1, wherein, The air pressure detection unit includes N air inlet pressure sensors arranged one-to-one at the air inlets of each stage compression cylinder of the multi-stage compression cylinder except the last stage compression cylinder, Each air inlet pressure sensor is used to detect the air inlet pressure value P1-PN at the air inlet of each stage compression cylinder of the multi-stage compression cylinder except the last stage compression cylinder, wherein P1 is the air inlet pressure value of the first stage compression cylinder, PN is the air inlet pressure value of the Nth stage compression cylinder, N is a positive integer, N=M-1, and M represents the total number of stages of the multi-stage compression cylinder.

3. The multi-stage compression gas compression system of claim 2, wherein, The control unit includes a main control module and N control valve groups, wherein The N control valve groups are arranged one-to-one on the oil side pipeline of each compression cylinder of the multi-stage compression cylinder except the first stage compression cylinder, and each control valve group is used to control the on-off of the oil circuit of the corresponding compression cylinder.

4. The multi-stage compression gas compression system of claim 3, wherein, The signal output end of the N air inlet pressure sensors is connected to the N signal input ends of the main control module one-to-one.

5. The multi-stage compression gas compression system of claim 4, wherein, The N control valve groups are electric control valves, and the signal input end of the N control valve groups is connected to the N signal output ends of the main control module one-to-one.

6. The multi-stage compression gas compression system of claim 4, wherein, The main control module includes N comparators and a threshold storage, the first signal input end of the N comparators is connected to the N air inlet pressure sensors one-to-one, the second signal input end of the N comparators is connected to the threshold storage, and the signal output end of the N comparators is connected to the signal input end of the N control valve groups one-to-one, wherein The comparator is used to compare the air inlet pressure value output by the air inlet pressure sensor connected thereto with the opening valve pressure threshold value stored in the threshold storage, and output a corresponding level signal to the control valve group connected thereto according to the comparison result, so as to control the opening or closing of the control valve group through the level signal.

7. The multi-stage compression gas compression system of claim 4, wherein, The control valve group is a manually controlled valve.

8. The multi-stage compression gas compression system of claim 7, wherein, It also includes N switch valve prompting modules, and the N switch valve prompting modules are arranged one-to-one on the N control valve groups.

9. The multi-stage compressed gas compression system of claim 8, wherein, The master control module comprises N comparators and a threshold storage, first signal inputs of the N comparators are connected with the N air inlet pressure sensors one by one, second signal inputs of the N comparators are connected with the threshold storage, signal outputs of the N comparators are connected with signal inputs of the N switch valve prompt modules one by one, wherein, The comparator is used for comparing the air inlet pressure value output by the air inlet pressure sensor connected therewith with the valve opening pressure threshold value stored in the threshold storage, and outputting a corresponding level signal to the switch valve prompt module connected therewith according to the comparison result, so as to control the switch valve prompt module to output a corresponding prompt signal through the level signal.

10. A multi-stage compressed gas compression system according to any one of claims 3-9, characterized in that, The control valve group comprises a first control valve for controlling the on-off of the oil inlet / outlet port of the corresponding compression cylinder and / or a second control valve for controlling the on-off of the oil outlet / inlet port of the corresponding compression cylinder.

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