Piston-type gas injection device

Abstract

The present invention provides a piston-type gas injection device. The piston-type gas injection device comprises: at least two injection cylinders, at least two of which have different volumes and maximum injection flows; a detection pipeline; and a gas source pipeline, wherein the detection pipeline is used to connect the device to be tested, and the gas source pipeline is used to connect the gas source; any one of the at least two injection cylinders can be selectively connected to the detection pipeline or the gas source pipeline. The piston-type gas injection device of the technical solution of the present invention can meet the gas injection requirements of different gas injection flows and precision requirements.

Description

Technical Field

[0001] The invention relates to the technical field of gas injection equipment, in particular to a piston type gas injection device. Background Art

[0002] With the development of science and technology, modern industrial production and manufacturing technology have also made great progress, but gases still play an indispensable role in the industrial field. For example, the chemical, pharmaceutical, metallurgical, electronic, energy and other fields all require various gases such as hydrogen, oxygen, nitrogen, argon, etc.

[0003] Generally speaking, industrial gas equipment has different requirements for the pressure and flow of different gases. In particular, the pressure requirement is generally quite different from the pressure of the gas source. Therefore, it is generally not possible to supply gas directly from the gas source to industrial gas equipment. It is generally necessary to supply gas to industrial gas equipment through a gas distribution device.

[0004] Generally speaking, industrial gas equipment has different requirements for the pressure and flow of different gases, especially the pressure requirement is generally different from the pressure of the gas source. Therefore, it is generally not possible to directly supply gas from the gas source to industrial gas equipment, and it is generally necessary to supply gas to industrial gas equipment through a gas distribution device. Existing gas flow meters all have the problem of limited use range. The gas flow injection range and accuracy of a single gas flow meter are greatly limited, and it is difficult to meet the calibration requirements of different types of equipment used to receive and inject gas. Summary of the invention

[0005] The main purpose of the present invention is to provide a piston-type gas injection device that can meet the gas injection needs of different gas injection flow rates and accuracy requirements.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided a piston-type gas injection device, comprising: at least two injection cylinders, at least two of which have different volumes and maximum injection flow rates; a detection pipeline; and a gas source pipeline, the detection pipeline being used to connect to a device under test, and the gas source pipeline being used to connect to a gas source; any one of the at least two injection cylinders can be selectively connected to the detection pipeline or the gas source pipeline.

[0007] Furthermore, the piston-type gas injection device also includes a control valve group, which is connected between the injection cylinder, the detection pipeline and the gas source pipeline, and enables the injection cylinder to be selectively connected to the detection pipeline and the gas source pipeline.

[0008] Furthermore, the control valve group includes: at least two first valves, which are arranged in a one-to-one correspondence with the injection cylinders and connected to each other, the first valve has two gas interfaces that can be selectively connected to the injection cylinders, and one of the gas interfaces of the first valve is used to connect with the outside air; at least two first air pipes, which are arranged in a one-to-one correspondence with the first valves, and the first end of the first air pipe is connected to the other gas interface of the corresponding first valve; at least two second valves, which are arranged in a one-to-one correspondence with the first air pipes, and the second valve is connected to the second end of the first air pipe; when the air source pipeline is connected to one of the second valves, it is not connected to the other second valves.

[0009] Furthermore, a control valve is provided on the gas source pipeline. When the first valve is connected to the first air pipe, the second valve is opened and the control valve opens the gas source pipeline; when the first valve is connected to the outside air, the second valve is opened and the control valve closes the gas source pipeline.

[0010] Furthermore, the control valve group includes: at least two third valves, which are arranged one-to-one corresponding to the injection cylinders, and the detection pipeline is connected to the third valves and can be selectively connected to each third valve; at least two second air pipes, which are arranged one-to-one corresponding to the injection cylinders, and the second air pipes are connected between the corresponding injection cylinders and the third valves.

[0011] Furthermore, the piston-type gas injection device also includes: a base; a first fixed plate; a guide plate; and a driving mechanism; at least two injection cylinders include a cylinder body and a cylinder rod, the first end of the cylinder body is fixedly mounted on the base, the first fixed plate is fixedly connected to the second end of the cylinder body, the movable ends of the cylinder rods are commonly connected to the guide plate, the driving mechanism is mounted on the first fixed plate, the driving end of the driving mechanism is drivingly connected to the guide plate, and drives the guide plate to move in a direction away from or close to the first fixed plate.

[0012] Furthermore, the piston type gas injection device also includes a second fixed plate, the second fixed plate is fixedly connected to the first fixed plate via a guide rod, and the guide plate is slidably arranged along the guide direction of the guide rod.

[0013] Furthermore, the driving mechanism includes a driving motor and a driving screw, the first end of the driving screw is connected to the output end of the driving motor, the second end of the driving screw is connected to the second fixed plate, and rotates circumferentially relative to the second fixed plate and has a fixed axial position, the guide plate is threadedly driven and connected to the driving screw, the driving motor is installed on a side of the first fixed plate away from the second fixed plate, and is located between the cylinder bodies of at least two injection cylinders.

[0014] Furthermore, at least two injection cylinders have the same stroke, and the cylinder rods are connected to the guide plate via a floating joint; and / or, at least two injection cylinders include a first cylinder, a second cylinder, a third cylinder and a fourth cylinder, the injection volume range of the first cylinder is [0, A], the injection volume range of the second cylinder is [0, B]; the injection volume range of the third cylinder is [0, C]; the injection volume range of the fourth cylinder is [0, D], wherein A<B<C<D.

[0015] Furthermore, a stroke monitoring device is fixedly arranged between the first fixed plate and the second fixed plate, and the stroke monitoring device is configured to monitor the stroke of the guide plate.

[0016] By applying the technical solution of the present invention, a detection pipeline, an air source pipeline and multiple injection cylinders with different volumes and maximum injection flow rates are set, and the detection pipeline and the air source pipeline can be selectively connected to at least two injection cylinders. In this way, when injecting gas, the staff can control the air source pipeline and the detection pipeline to be connected to appropriate injection cylinders according to the injection flow rate and injection accuracy requirements. At the same time, the injected gas is output through the detection pipeline and the one-way output connector to calibrate the tested equipment, which can not only reduce the consumption of the gas source, but also meet the gas injection needs with different gas injection flow rates and accuracy requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0018] Figure 1 A perspective view of a piston-type gas injection device according to an embodiment of the present invention is shown;

[0019] Figure 2 A schematic diagram showing the overall structure of a piston-type gas injection device according to an embodiment of the present invention; and

[0020] Figure 3 A schematic diagram showing the principle of a piston-type gas injection device according to an embodiment of the present invention is shown.

[0021] The above drawings include the following reference numerals:

[0022] 10. Injection cylinder; 10a. First cylinder; 10b. Second cylinder; 10c. Third cylinder; 10d. Fourth cylinder; 11. Base; 12. First fixed plate; 13. Guide plate; 14. Driving mechanism; 15. Cylinder body; 16. Cylinder rod; 17. Second fixed plate; 18. Guide rod; 19. Driving motor; 20. Detection pipeline; 21. Driving screw rod; 22. Stroke monitoring device; 23. Proximity switch; 30. Air source pipeline; 40. Second air pipe; 50. Control valve; 60. First valve; 70. First air pipe; 80. Second valve; 81. Third valve; 90. Pressure sensor. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] See also Figures 1 to 3 As shown, the present invention provides a piston-type gas injection device, comprising: at least two injection cylinders 10, the volumes and maximum injection flow rates of the at least two injection cylinders 10 are different; a detection pipeline 20; and a gas source pipeline 30, the detection pipeline 20 is used to connect to the device under test, and the gas source pipeline 30 is used to connect to the gas source; any one of the at least two injection cylinders 10 can be selectively connected to the detection pipeline 20 or the gas source pipeline 30.

[0025] In the above technical solution, the piston-type gas injection device includes at least two injection cylinders 10, a detection pipeline 20 for connecting the device under test, and a gas source pipeline 30 for connecting the gas source, the volume and maximum injection flow rate of the at least two injection cylinders 10 are different, and the detection pipeline 20 and the gas source pipeline 30 can be selectively connected to the at least two injection cylinders 10. When injecting gas, the staff can control the gas source pipeline 30 and the detection pipeline 20 to be connected to the appropriate injection cylinder 10 according to the injection flow rate and injection accuracy requirements, so as to meet the gas injection requirements with different gas injection flow rates and accuracy requirements.

[0026] In one embodiment, a one-way valve is provided on the detection pipeline 20, which is used to prevent the detection gas from flowing back from the device under test. That is, when the detection pipeline 20 is connected to the device under test, it can prevent the airflow in the device under test from flowing back to the injection cylinder 10 through the detection pipeline 20 to cause airflow fluctuations, thereby ensuring the smoothness of the airflow and improving the calibration accuracy.

[0027] It should be noted that in the embodiment of the present invention, the piston-type gas injection device uses a cylinder to inject gas, which can inject gas at a set volume flow rate as well as a set mass flow rate, and does not require periodic calibration like general measuring equipment.

[0028] like Figure 3 As shown, in one embodiment of the present invention, the piston-type gas injection device also includes a control valve group, which is connected between the injection cylinder 10, the detection pipeline 20 and the gas source pipeline 30, and enables the injection cylinder 10 to be selectively connected to the detection pipeline 20 and the gas source pipeline 30.

[0029] Through the above arrangement, the gas injection cylinder 10 can be connected to the detection pipeline 20 or the gas source pipeline 30, so as to realize real-time monitoring of the pressure of the injected gas and gas injection.

[0030] like Figure 3 As shown, in one embodiment of the present invention, the control valve group includes: at least two first valves 60, which are arranged in a one-to-one correspondence with the injection cylinder 10 and connected, and the first valve 60 has two gas interfaces that can be selectively connected to the injection cylinder 10, and one of the gas interfaces of the first valve 60 is used to communicate with the outside air; at least two first air pipes 70, which are arranged in a one-to-one correspondence with the first valve 60, and the first end of the first air pipe 70 is connected to the other gas interface of the corresponding first valve 60; at least two second valves 80, which are arranged in a one-to-one correspondence with the first air pipe 70, and the second valve 80 is connected to the second end of the first air pipe 70; when the gas source pipeline 30 is connected to one of the second valves 80, it is not connected to the other second valves 80. In the above technical solution, the first valve 60 has two gas interfaces that can be selectively connected to the injection cylinder 10, and one of the gas interfaces of the first valve 60 is used to communicate with the outside air, so that when the injection cylinder 10 is connected to the gas interface, the injection cylinder 10 is connected to the atmosphere. The first end of the first air pipe 70 is connected to another gas interface of the corresponding first valve 60, so that the two gas interfaces of the first valve 60 can be selectively opened or closed, and can control whether the corresponding injection cylinder 10 is connected to the first air pipe 70. The opening and closing of the second valve 80 can control whether the corresponding injection cylinder 10 is connected to the gas source pipeline 30, and when the gas source pipeline 30 is connected to one of the second valves 80, it is not connected to the other second valves 80. At this time, it is necessary to control the gas interface connected between the first valve 60 on the first air pipe 70 corresponding to the second valve 80 and the first air pipe 70 to open, so that the injection cylinder 10 is not connected to the atmosphere, so as to perform gas injection as a working cylinder, and control the gas interface connected to the atmosphere of the first valve 60 on the first air pipe 70 corresponding to the other second valves 80 to open, so that the other injection cylinders 10 are connected to the atmosphere and not used as working cylinders, thereby realizing the free switching of cylinders of different specifications as working cylinders or non-working cylinders, thereby meeting the gas injection requirements with different gas injection flow and accuracy requirements.

[0031] In one embodiment of the present invention, the control valve 50 is a normally closed two-position three-way valve, the second valve 80 is a manifold type direct-acting solenoid valve, and the first valve 60 is a normally open two-position three-way valve.

[0032] like Figure 3 As shown, in one embodiment of the present invention, a control valve 50 is provided on the gas source pipeline 30. When the first valve 60 is connected to the first air pipe 70, the second valve 80 is opened, and the control valve 50 opens the gas source pipeline 30; when the first valve 60 is connected to the outside air, the second valve 80 is opened, and the control valve 50 closes the gas source pipeline 30. When the injection cylinder 10 injects gas into the detection pipeline 20, the control valve 50 loses power and closes the gas source pipeline 30. When the gas source injects gas into the injection cylinder 10, it is powered on and opens the gas source pipeline 30. In the above technical solution, the first valve 60 is a normally open two-position three-way valve. Therefore, when the first valve 60 loses power, the first valve 60 controls the first air pipe 70 to be connected to the injection cylinder 10, and the atmosphere is not connected to the injection cylinder 10; when the first valve 60 is powered on, the first valve 60 controls the first air pipe 70 to be not connected to the injection cylinder 10, and the atmosphere is connected to the injection cylinder 10. The control valve 50 is a normally closed two-position three-way valve. When the first valve 60 controls the first air pipe 70 to be connected to the injection cylinder 10, the second valve 80 is opened, and the control valve 50 on the gas source pipeline 30 is energized, so that the gas source pipeline 30 is in a passage state, the injection cylinder 10 is connected to the gas source pipeline 30, and the gas source can inject gas into the injection cylinder 10; when the first valve 60 controls the outside air to be connected to the injection cylinder 10, the second valve 80 is opened, the control valve 50 loses power, and the gas source pipeline 30 is closed. At this time, the injection cylinder 10 is connected to the outside air and does not serve as a working cylinder; and when the injection cylinder 10 injects gas into the detection pipeline 20, the control valve 50 is in a state of closing the gas source pipeline 30. At this time, the injection cylinder 10 is not connected to the gas source pipeline 30, and the injection cylinder 10 injects gas into the detection pipeline 20 to monitor the injection gas pressure in real time.

[0033] In one embodiment of the present invention, at least two first valves 60 are integrated into a valve group, and at least two second valves 80 are integrated into a valve group. This can not only reduce the installation space and make the device structure more compact, but also realize the switching of different injection gas amounts and injection precisions by freely switching the connection states of multiple cylinders and control valves 50 or second air pipes 40, thereby meeting more injection requirements and improving the applicability of the device.

[0034] like Figure 3As shown, in one embodiment of the present invention, the control valve group includes: at least two third valves 81, which are arranged one by one corresponding to the injection cylinders 10, and the detection pipeline 20 is connected to the third valves 81 and can be selectively connected to each third valve 81; at least two second air pipes 40, which are arranged one by one corresponding to the injection cylinders 10, and the second air pipes 40 are connected between the corresponding injection cylinders 10 and the third valves 81.

[0035] In one embodiment of the present invention, the third valve 81 is a manifold type direct-acting solenoid valve.

[0036] In the above technical solution, the detection pipeline 20 is connected to the third valve 81 and can be selectively connected to each third valve 81. The second air pipe 40 is connected between the corresponding injection cylinder 10 and the third valve 81. When gas detection is required for a certain injection cylinder 10, it is necessary to open the third valve 81 corresponding to the injection cylinder 10, close the third valves 81 corresponding to other injection cylinders 10, and connect the detection pipeline 20 with the third valve 81 corresponding to the injection cylinder 10 to be detected, thereby realizing real-time monitoring of the gas pressure injected into the injection cylinder 10 to be tested and ensuring the stability of gas injection.

[0037] Specifically, in one embodiment of the present invention, a pressure sensor 90 is provided at the injection end of each detection pipeline 20, which can monitor the pressure of the injected gas in real time. In this way, the controller can correct the injection speed according to the feedback data of the pressure sensor 90 to ensure the stability of gas injection.

[0038] like Figure 2 As shown, in one embodiment of the present invention, the piston-type gas injection device also includes: a base 11; a first fixed plate 12; a guide plate 13; and a driving mechanism 14; at least two injection cylinders 10 include a cylinder body 15 and a cylinder rod 16, the first end of the cylinder body 15 is fixedly mounted on the base 11, the first fixed plate 12 is fixedly connected to the second end of the cylinder body 15, the movable ends of the cylinder rod 16 are commonly connected to the guide plate 13, the driving mechanism 14 is mounted on the first fixed plate 12, and the driving end of the driving mechanism 14 is drivingly connected to the guide plate 13, driving the guide plate 13 to move in a direction away from or close to the first fixed plate 12.

[0039] In the above technical solution, the cylinder body 15 is fixedly installed between the base 11 and the first fixed plate 12. Driven by the drive motor 19, the guide plate 13 can drive the cylinder rod 16 to move away from or close to the cylinder body 15, thereby achieving air extraction and gas injection.

[0040] It should be noted that, in one embodiment of the present invention, a proximity switch 23 is installed on the first fixed plate 12. When the guide plate 13 contacts the proximity switch 23, it reaches the zero position. At this time, all the gas in the injection cylinder 10 is discharged. The controller can control the drive motor 19 to stop according to the feedback signal of the proximity switch 23, so that the cylinder rod 16 stops moving.

[0041] like Figure 2 As shown, in one embodiment of the present invention, the piston type gas injection device further includes a second fixed plate 17 , which is fixedly connected to the first fixed plate 12 via a guide rod 18 , and the guide plate 13 is slidably arranged along the guide direction of the guide rod 18 .

[0042] In the above technical solution, the second fixed plate 17 is fixedly connected to the first fixed plate 12 via the guide rod 18, and the guide plate 13 is slidably arranged along the guide direction of the guide rod 18. In this way, the guide rod 18 can limit the guide plate 13 in the horizontal direction, thereby making the movement of the cylinder rod 16 in the vertical direction more stable and preventing movement.

[0043] like Figure 2 As shown, in one embodiment of the present invention, the driving mechanism 14 includes a driving motor 19 and a driving screw 21, the first end of the driving screw 21 is connected to the output end of the driving motor 19, the second end of the driving screw 21 is connected to the second fixed plate 17, and rotates circumferentially relative to the second fixed plate 17 and has a fixed axial position, the guide plate 13 is threadedly driven and connected to the driving screw 21, the driving motor 19 is installed on the side of the first fixed plate 12 away from the second fixed plate 17, and is located between the cylinder bodies 15 of at least two injection cylinders 10.

[0044] Through the above arrangement, under the driving action of the driving motor 19, the guide plate 13 moves along the driving screw 21 in the vertical direction, thereby driving the cylinder rod 16 to move in the vertical direction to achieve air extraction and exhaust. The driving motor 19 is located between the cylinder bodies 15 of at least two injection cylinders 10, which can not only ensure the structural stability of the entire device, but also save installation space and make the structure more compact.

[0045] like Figure 2 As shown, in one embodiment of the present invention, at least two injection cylinders 10 have the same stroke and different cylinder diameters, and the cylinder rod 16 is connected to the guide plate 13 through a floating joint. When different injection cylinders 10 run the same stroke, the injected gas volume and flow rate are different. In this embodiment, the injection cylinders 10 have the same stroke, the same injection speed, and different volumes. When the injection is synchronized, the injection flow rate is different. The working environment of each injection cylinder 10 is the same, and the operating actions are consistent. Therefore, the control consistency is good, and the calibration consistency of different devices under test is good under various working conditions.

[0046] In this embodiment, cylinders of different specifications are used as the injection cylinders 10, and a variety of cylinders of different specifications can be selected for gas injection, thereby achieving gas injection in different flow ranges. Since a variety of cylinders of different specifications are combined, it is possible to use a small-volume and small-flow cylinder to achieve high-precision micro-flow gas injection, and quantitatively inject a micro-flow with high precision to meet the needs of high-precision micro-flow gas injection equipment, and at the same time, other cylinders can be used to make up for the limited flow range of small-volume and small-flow cylinders, which cannot achieve the defect of gas injection outside the flow range, so that the piston-type gas injection device can achieve gas injection in a large flow range, and at the same time can effectively improve the injection precision of micro-flow gas.

[0047] In one embodiment, at least two injection cylinders 10 include a first cylinder 10a, a second cylinder 10b, a third cylinder 10c and a fourth cylinder 10d, the injection volume range of the first cylinder 10a is [0, A], the injection volume range of the second cylinder 10b is [0, B]; the injection volume range of the third cylinder 10c is [0, C]; the injection volume range of the fourth cylinder 10d is [0, D], wherein A<B<C<D.

[0048] In the above technical solution, the first cylinder 10a, the second cylinder 10b, the third cylinder 10c and the fourth cylinder 10d have different volumes and different maximum gas injection flow rates. In this way, the injection equipment can cover injection volume requirements of multiple gradients, thereby effectively improving the applicability of the device.

[0049] It should be noted that, in one embodiment of the present invention, the injection accuracy of the first cylinder 10a is c1, and the maximum injection flow rate is 29ml / min, the injection accuracy of the second cylinder 10b is c2, and the maximum injection flow rate is 150ml / min, the injection accuracy of the third cylinder 10c is c3, and the maximum injection flow rate is 367ml / min, and the injection accuracy of the fourth cylinder 10d is c4, and the maximum injection flow rate is 1034ml / min. The maximum injection flow rates of the first cylinder 10a, the second cylinder 10b, the third cylinder 10c and the fourth cylinder 10d increase, and the injection accuracy gradually decreases. That is, the smaller the maximum injection flow rate of the four cylinders, the higher the injection accuracy, and the larger the maximum injection flow rate, the lower the injection accuracy. When selecting a working cylinder, first determine the cylinder that meets the gas injection flow rate requirement, that is, determine whether the required gas injection flow rate is within the maximum injection flow rate range of the cylinder. If so, the gas injection flow rate requirement is met, otherwise, the gas injection flow rate requirement is not met. After determining the cylinder that meets the gas injection flow rate requirement, the cylinder with the highest accuracy can be selected from these cylinders for gas injection, thereby improving the gas injection accuracy and the calibration accuracy of the equipment under test.

[0050] For example, when the required injection flow rate of the injected gas is 20 ml / min, the first cylinder 10a, the second cylinder 10b, the third cylinder 10c and the fourth cylinder 10d all meet the maximum injection flow rate requirement, but the injection accuracy c1 of the first cylinder 10a is higher than that of the second cylinder 10b, the third cylinder 10c and the fourth cylinder 10d. Therefore, the first cylinder 10a is selected as the working cylinder for injecting gas; when the required injection flow rate of the injected gas is 160 ml / min, the injection accuracy c1 of the first cylinder 10a is higher than that of the second cylinder 10b, the third cylinder 10c and the fourth cylinder 10d. The maximum injection flow rate range of the first cylinder 10a and the second cylinder 10b is exceeded, so the first cylinder 10a and the second cylinder 10b cannot meet the required injection flow rate requirements. The required injection flow rate of the injected gas is within the maximum injection flow rate range of the third cylinder 10c and the fourth cylinder 10d, but the injection accuracy c3 of the third cylinder 10c is higher than the injection accuracy c4 of the fourth cylinder 10d. Therefore, the third cylinder 10c is selected as the working cylinder injection gas to better meet the calibration requirements.

[0051] like Figure 2 As shown, in one embodiment of the present invention, a travel monitoring device 22 is fixedly disposed between the first fixing plate 12 and the second fixing plate 17 , and the travel monitoring device 22 is configured to monitor the travel of the guide plate 13 .

[0052] Through the above arrangement, the movement path of the guide plate 13 can be monitored in real time, the movement distance and movement speed of the cylinder rod 16 can be controlled, and closed-loop control of the injection amount and injection speed can be achieved.

[0053] Preferably, in one embodiment of the present invention, the travel monitoring device 22 is a grating ruler.

[0054] Specifically, the working process of the piston type gas injection device and the gas path cleaning process are as follows:

[0055] Working process: the system automatically selects a suitable injection cylinder 10 such as the first cylinder 10a according to the gas injection amount; closes the first valve 60 on the second air pipe 40 of the first cylinder 10a, opens the second valve 80 arranged on the first air pipe connected to the first cylinder 10a, and makes the first cylinder 10a serve as the working cylinder, and at the same time opens the first valve 60 on the second air pipe 40 of the remaining injection cylinders 10, namely the second cylinder 10b, the third cylinder 10c and the fourth cylinder 10d, closes the second valve 80 arranged on the first air pipe connected to the injection cylinder 10, so that the second cylinder 10b, the third cylinder 10c and the fourth cylinder 10d are all connected to the atmosphere and do not serve as working cylinders; the drive motor 19 is started to drive the cylinder rod 16 to extract the gas source; after the working cylinder body is fully pumped, the control valve 50 switches the gas circuit to the exhaust mode, and the drive motor 19 is started to drive the cylinder rod 16 to discharge the gas in the cylinder. The above process is repeated many times until all non-gas source gases in the entire gas circuit and cylinder are discharged, thereby ensuring the purity of the gas along the entire route; after cleaning is completed, the drive motor 19 is started to drive the cylinder rod 16 to extract the required amount of gas source gas, the control valve 50 switches the gas circuit to the exhaust mode, the drive motor 19 is started to drive the cylinder rod 16 to discharge the gas in the first cylinder 10a, and the gas injection is completed.

[0056] When the injection of one gas is completed and it is necessary to switch to another injection cylinder 10 such as the second cylinder 10b to inject another gas, the switching process is as follows: open the first valve 60 on the second air pipe 40 of the first cylinder 10a, and close the second valve 80 set on the first air pipe connected to the first cylinder 10a, so that the first cylinder 10a is connected to the atmosphere and does not serve as a working cylinder; at the same time, close the first valve 60 on the second air pipe 40 of the second cylinder 10b, and open the second valve 80 set on the first air pipe connected to the second cylinder 10b, so that the second cylinder 10b is used as a working cylinder. After the switching is completed, repeat the above-mentioned gas cleaning process; start the drive motor 19 to drive the cylinder rod 16 to extract the required injection amount of gas source gas, and control the valve 50 to switch the gas circuit to the exhaust mode; start the drive motor 19 to drive the cylinder rod 16 to discharge the gas in the second cylinder 10b to complete the gas injection.

[0057] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: by setting a detection pipeline, a gas source pipeline and a plurality of injection cylinders with different volumes and maximum injection flow rates, and the detection pipeline and the gas source pipeline can be selectively connected to at least two injection cylinders, so that when the gas is injected, the staff can control the gas source pipeline and the detection pipeline to be connected to the appropriate injection cylinder according to the injection flow rate and injection accuracy requirements. At the same time, the injected gas is output through the detection pipeline and the one-way output connector to calibrate the tested equipment, which can not only reduce the consumption of the gas source, but also meet the gas injection requirements with different gas injection flow rates and accuracy requirements.

[0058] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0059] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A piston type gas injection device, characterized in that: include: At least two injection cylinders (10), wherein the at least two injection cylinders (10) have different volumes and maximum injection flow rates; A detection pipeline (20); and An air source pipeline (30), wherein the detection pipeline (20) is used to connect to the device under test, and the air source pipeline (30) is used to connect to an air source; Any one of the at least two gas injection cylinders (10) is in communication with the detection pipeline (20) or the gas source pipeline (30); The piston-type gas injection device further comprises a control valve group, wherein the control valve group is connected between the injection cylinder (10), the detection pipeline (20) and the gas source pipeline (30), and enables the injection cylinder (10) to communicate with the detection pipeline (20) or the gas source pipeline (30); The control valve group comprises: at least two first valves (60), which are arranged in one-to-one correspondence with and connected to the injection cylinders (10), wherein the first valves (60) have two gas interfaces in communication with the injection cylinders (10), and one of the gas interfaces of the first valves (60) is used to communicate with external air; At least two first air pipes (70) are arranged in one-to-one correspondence with the first valves (60), and the first ends of the first air pipes (70) are connected to another gas interface of the corresponding first valve (60); at least two second valves (80), arranged in one-to-one correspondence with the first air pipes (70), the second valves (80) being connected to the second ends of the first air pipes (70); When the gas source pipeline (30) is connected to one of the second valves (80), it is not connected to the other second valves (80); The gas source pipeline (30) is provided with a control valve (50); when the first valve (60) is connected to the first gas pipe (70), the second valve (80) is opened, and the control valve (50) opens the gas source pipeline (30); when the first valve (60) is connected to the outside air, the second valve (80) is opened, and the control valve (50) closes the gas source pipeline (30); The piston type gas injection device also includes: Base (11); A first fixing plate (12); a guide plate (13); and A driving mechanism (14); The at least two injection cylinders (10) comprise a cylinder body (15) and a cylinder rod (16); a first end of the cylinder body (15) is fixedly mounted on the base (11); the first fixed plate (12) is fixedly connected to the second end of the cylinder body (15); movable ends of the cylinder rods (16) are commonly connected to the guide plate (13); the driving mechanism (14) is mounted on the first fixed plate (12); a driving end of the driving mechanism (14) is drivingly connected to the guide plate (13) to drive the guide plate (13) to move in a direction away from or towards the first fixed plate (12).

2. The piston type gas injection device according to claim 1, characterized in that: The control valve group comprises: At least two third valves (81) are arranged in one-to-one correspondence with the injection cylinders (10), and the detection pipeline (20) is connected to the third valves (81) and communicates with each of the third valves (81); At least two second air pipes (40) are arranged in one-to-one correspondence with the injection cylinders (10), and the second air pipes (40) are connected between the corresponding injection cylinders (10) and the third valve (81).

3. The piston type gas injection device according to claim 1, characterized in that: The piston-type gas injection device further comprises a second fixed plate (17), the second fixed plate (17) being fixedly connected to the first fixed plate (12) via a guide rod (18), and the guide plate (13) being slidably arranged along the guide direction of the guide rod (18).

4. The piston type gas injection device according to claim 3, characterized in that: The driving mechanism (14) comprises a driving motor (19) and a driving screw (21); a first end of the driving screw (21) is connected to an output end of the driving motor (19); a second end of the driving screw (21) is connected to the second fixed plate (17), and is circumferentially rotatable relative to the second fixed plate (17) and has a fixed axial position; the guide plate (13) is threadedly connected to the driving screw (21); the driving motor (19) is mounted on a side of the first fixed plate (12) away from the second fixed plate (17), and is located between the cylinder bodies (15) of the at least two injection cylinders (10).

5. The piston type gas injection device according to claim 1, characterized in that: The at least two injection cylinders (10) have the same stroke, and the cylinder rod (16) is connected to the guide plate (13) via a floating joint; and / or the at least two injection cylinders (10) include a first cylinder (10a), a second cylinder (10b), a third cylinder (10c) and a fourth cylinder (10d), the injection volume range of the first cylinder (10a) is [0, A], the injection volume range of the second cylinder (10b) is [0, B]; the injection volume range of the third cylinder (10c) is [0, C]; the injection volume range of the fourth cylinder (10d) is [0, D], wherein A<B<C<D.

6. The piston type gas injection device according to claim 3, characterized in that: A stroke monitoring device (22) is fixedly arranged between the first fixed plate (12) and the second fixed plate (17), and the stroke monitoring device (22) is configured to monitor the stroke of the guide plate (13).

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