High-repeatability oil chromatography gas sample automatic injection device and use method

Abstract

The invention relates to the technical field of oil chromatography gas sample detection, in particular to a high-repeatability oil chromatography gas sample automatic injection device and a using method.The high-repeatability oil chromatography gas sample automatic injection device comprises a gas supply device, a gas pipeline, a gas sample chamber and a chromatographic instrument, and the gas supply device is communicated with the gas sample chamber through the gas pipeline; the input end of the chromatographic instrument is communicated with the gas sample chamber through the gas pipeline, the gas supply device comprises a pressurizing gas pump, a vacuum pump and an injector, the pressurizing gas pump is communicated with a first joint of a three-way valve through the gas pipeline, and a second joint of the three-way valve is communicated with the vacuum pump; a third connector of the three-way valve is communicated with a driving gas port of the gas sample chamber, a detection gas port of the gas sample chamber is communicated with the injector and the chromatographic instrument, a pressurizing gas pump, a vacuum pump and other devices are used for replacing manual work to control the injector, errors caused by repeated operation are reduced, and the accuracy of a detection result is improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil chromatography gas sample detection, in particular to a highly repeatable oil chromatography gas sample automatic injection device and a use method thereof. Background Art

[0002] In recent years, oil chromatography tests have become an important means to ensure the safe operation of oil-filled electrical equipment by judging the nature of internal faults in oil-filled electrical equipment. In the oil chromatography test, the repeatability of the operation of injecting the gas sample eluted from the insulating oil into the chromatograph is directly related to the accuracy of the oil chromatography test results. The national standard stipulates that the repeatability of the results of two injections of the same gas sample should be within ±1.5% of the average value (represented by ethylene content).

[0003] The existing method of injecting gas samples is: the test personnel first transfer the gas sample eluted from the oil into a 5 ml gas storage syringe, and then use a 1 ml glass syringe with an injection needle to extract 1 ml of the gas sample from the gas storage syringe. Then quickly insert the 1 ml syringe needle into the injection port of the chromatograph, and manually push the 1 ml syringe core to inject the gas sample into the instrument to complete the detection operation. Each time the gas sample is injected, the speed and volume of the gas sample must be highly consistent, otherwise it will cause great detection deviation.

[0004] Conventional manual injection operation is prone to errors such as syringe needle bending, core being pushed away by the front pressure of the chromatographic column, inconsistent injection speed, and accidental loss of gas sample. Due to the extremely high error rate of manual injection operation, the repeatability of the injection operation is always difficult to guarantee, which affects the accuracy of the oil chromatography test results. Summary of the invention

[0005] In response to the above technical problems, the present invention provides a highly repeatable oil chromatography gas sample automatic injection device and a method of use, which uses a pressurized air pump, a vacuum pump and other devices instead of manual control of the syringe, reducing the error of repeated operations and improving the accuracy of the test results.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A highly repeatable automatic oil chromatography gas sample injection device comprises an air supply device, an air pipeline, a gas sample chamber and a chromatograph, wherein the air supply device is connected to the gas sample chamber through the air pipeline, and the input end of the chromatograph is connected to the gas sample chamber through the air pipeline, and the air supply device comprises a pressurized air pump, a vacuum pump and a syringe, wherein the pressurized air pump is connected to a first joint of a three-way valve through the air pipeline, and the second joint of the three-way valve is connected to the vacuum pump; the third joint of the three-way valve is connected to a driving air port of the gas sample chamber, and the detection air port of the gas sample chamber is connected to the syringe and the chromatograph.

[0008] Furthermore, the gas supply device also includes a gas cylinder and a connector, the input end of the connector is connected to the gas cylinder and the driving gas port of the gas sample chamber, and the output end of the connector is connected to the input end of the chromatograph.

[0009] Furthermore, the output end of the pressurized air pump is communicated with the booster cylinder, the booster cylinder is connected to the first pressure controller, and the output end of the booster cylinder is communicated with the driving air port of the gas sample chamber.

[0010] Furthermore, the output end of the booster cylinder is connected to the first connector of the three-way valve through a first solenoid valve; and the pressurized air pump is connected to the booster cylinder through a one-way valve.

[0011] Furthermore, a bellows push tube is provided inside the gas sample chamber, one end of the bellows push tube is fixed to the driving gas port of the gas sample chamber, and the other end of the bellows push tube is slidably matched with the inner wall of the gas sample chamber; a first photoelectric controller is provided at the driving gas port end of the gas sample chamber, and a second photoelectric controller is provided at the detection gas port end of the gas sample chamber; a second pressure controller and a third solenoid valve are provided in the middle of the gas sample chamber, and the third solenoid valve is connected to the vacuum pump through an air pipeline; the detection gas port of the gas sample chamber is connected to the gas supply port and the second solenoid valve in sequence, the gas supply port is connected to the syringe, and the output end of the second solenoid valve is connected to the connector.

[0012] Furthermore, the chromatograph comprises a programmable logic controller, an input end of the programmable logic controller is connected to the gas pipeline, and an output end of the programmable logic controller is connected to the chromatograph.

[0013] A method for using a highly repeatable oil chromatography gas sample automatic injection device comprises the following steps:

[0014] Sample preparation;

[0015] Inject gas sample;

[0016] Gas sample chamber removes residue;

[0017] Prepare for injection again.

[0018] Furthermore, the sample injection preparation comprises the following steps:

[0019] Connect the chromatograph and the gas sample chamber via a connector;

[0020] Input the sample gas to be tested into the syringe;

[0021] Connect the syringe and the gas sample chamber;

[0022] Start the programmable logic controller;

[0023] Start the pressurized air pump to inject a specified amount of compressed air into the gas sample chamber;

[0024] Start the vacuum pump to extract air outside the gas sample chamber until the first photoelectric controller is turned on and the second pressure controller reaches the set value.

[0025] Further, the injecting gas sample comprises the following steps:

[0026] Use a syringe to input the test gas sample into the gas sample chamber;

[0027] Start the pressurized air pump to deliver compressed air into the gas sample chamber, so that the bellows push tube pushes the test gas sample to the connector;

[0028] Start the gas cylinder, which releases the working carrier gas to push the test gas sample into the chromatograph.

[0029] Furthermore, the gas sample chamber removing residues comprises the following steps:

[0030] Open the second connector and the third connector of the three-way valve, and open the third solenoid valve;

[0031] Start the vacuum pump to extract the gas in the gas sampling chamber.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The present invention uses devices such as a pressurized air pump and a vacuum pump to replace manual control of the syringe, thereby reducing the error of repeated operations and improving the accuracy of the test results.

[0034] 2. The present invention standardizes the operation process of oil chromatography test, reduces the operation difficulty of oil chromatography test, adopts the design of pneumatic expansion and contraction of elastic element for gas sample injection, and utilizes the built-in gas injection expansion and contraction elastic element of photoelectric control and pressure difference control device to make its operation speed completely consistent with manual injection, and ensures that the volume of the injected gas sample is also consistent, thereby realizing high repeatability operation of oil chromatography gas sample injection.

[0035] 3. The sample preparation process of the present invention also effectively solves the problem of mutual interference and contamination of residues of different measured gas samples.

[0036] 4. The present invention is easy to install and use, does not change the original operation process, does not make any destructive modifications to the oil chromatograph, and does not change the original performance of the oil chromatograph. It can be used on various oil chromatographs and is very suitable for use in power oil chromatography tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural schematic diagram of the present invention;

[0038] Figure 2 is a schematic diagram of the structure of the gas sample chamber;

[0039] Figure 3 A circuit diagram of the present invention;

[0040] Figure 4 FIG. 4 is a circuit diagram of a switch of the present invention.

[0041] The reference numerals in the accompanying drawings are:

[0042] 11. Pressurized air pump; 12. Gas cylinder; 13. Booster cylinder; 14. First pressure controller; 15. Vacuum pump; 16. Syringe; 17. Connector; 2. Gas pipeline; 21. First solenoid valve; 22. Three-way valve; 23. One-way valve; 3. Gas sample chamber; 31. Bellows push tube; 32. First photoelectric controller; 33. Second photoelectric controller; 34. Second pressure controller; 35. Gas delivery port; 36. Second solenoid valve; 37. Third solenoid valve; 4. Chromatograph; 41. Programmable logic controller. DETAILED DESCRIPTION

[0043] like Figure 1-Figure 4 As shown, the highly repeatable oil chromatography gas sample automatic injection device of this embodiment comprises an air supply device, an air pipeline 2, a gas sample chamber 3 and a chromatograph 4. The air supply device is connected with the gas sample chamber 3 through the air pipeline 2, and the input end of the chromatograph 4 is connected with the gas sample chamber 3 through the air pipeline 2. The air supply device comprises a pressurized air pump 11, a vacuum pump 15 and an injector 16. The pressurized air pump 11 is connected with the first joint of the three-way valve 22 through the air pipeline 2, and the second joint of the three-way valve 22 is connected with the vacuum pump 15; the third joint of the three-way valve 22 is connected with the driving air port of the gas sample chamber 3, and the detection air port of the gas sample chamber 3 is connected with the injector 16 and the chromatograph 4.

[0044] The gas sample chamber 3 is a stainless steel cylinder with an inner diameter of about 18 mm, a length of about 50 mm, a smooth inner wall, and is installed horizontally. The effective gas sample volume that can be accommodated is about 1 ml. One side of the cylinder of the gas sample chamber 3 is conical, and the other side is flat.

[0045] Furthermore, the gas supply device also includes a gas cylinder 12 and a connector 17 , the input end of the connector 17 is connected to the gas cylinder 12 and the driving gas port of the gas sample chamber 3 , and the output end of the connector 17 is connected to the input end of the chromatograph 4 .

[0046] The connector 17 is a stainless steel cylinder about 15 mm long. Both ends of the cylinder are internally threaded, one end is connected to the second electromagnetic valve 36, and the other end is connected to the inlet of the chromatograph 4. There is an airway with a diameter of 1.5 mm at the center of the cylinder, and the inlet and outlet of the airway have a conical protrusion with an outer diameter of 3 mm, which is used for sealing connection with the inlet of the chromatograph 4.

[0047] Furthermore, the output end of the pressurized air pump 11 is connected to the booster cylinder 13 , the booster cylinder 13 is connected to the first pressure controller 14 , and the output end of the booster cylinder 13 is connected to the driving air port of the gas sample chamber 3 .

[0048] Furthermore, the output end of the booster cylinder 13 is connected to the first connector of the three-way valve 22 through the first solenoid valve 21 ; the pressurized air pump 11 is connected to the booster cylinder 13 through the one-way valve 23 .

[0049] The booster cylinder 13 is a cylindrical stainless steel container with a volume of 0.2 liters, one side of which is connected to the pressurized air pump 11 through a one-way valve 23, and the other side is connected to the first solenoid valve 21. A first pressure controller 14 is installed on it to monitor the pressure change of the booster compressed air in the cylinder. It is mainly used to store booster compressed air for injection drive and provide extended injection thrust for the active end of the injection bellows push tube 31.

[0050] Furthermore, a bellows push tube 31 is arranged inside the gas sample chamber 3, one end of the bellows push tube 31 is fixed to the driving air port of the gas sample chamber 3, and the other end of the bellows push tube 31 is slidably matched with the inner wall of the gas sample chamber 3; a first photoelectric controller 32 is arranged at the driving air port end of the gas sample chamber 3, and a second photoelectric controller 33 is arranged at the detection air port end of the gas sample chamber 3; a second pressure controller 34 and a third solenoid valve 37 are arranged in the middle of the gas sample chamber 3, and the third solenoid valve 37 is connected to the vacuum pump 15 through the air pipeline 2; the detection air port of the gas sample chamber 3 is connected to the gas supply port 35 and the second solenoid valve 36 in sequence, the gas supply port 35 is connected to the syringe 16, and the output end of the second solenoid valve 36 is connected to the connector 17.

[0051] The injection bellows push tube 31 is a stainless steel high-elastic bellows with a telescopic length of about 25-40 mm and a diameter of about 17.8 mm. One end of the bellows is sealed and fixedly welded to the conical side of the gas sample chamber 3, which is the fixed end, and the other end is a movable end with a ball and a hard sealing surface. It can be telescopically moved left and right in the gas sample chamber 3 under the action of vacuum negative pressure and booster compressed air pressure, thereby driving the sealing surface of the movable end to overcome the internal carrier gas pressure of the oil chromatograph 4 and inject the measured gas sample into the injection gas path of the chromatograph 4; the first photoelectric controller 32 and the second photoelectric controller 33 are both composed of a miniature infrared light emitter and a photosensitive receiver, which are relatively embedded in the conical side and the plane side outer wall of the gas sample chamber 3, and are mainly used to trigger the "ready for injection" and "injection end" signals. When the movable end of the injection bellows push tube 31 is compressed to the conical side of the gas sample chamber 3 by the vacuum negative pressure, the infrared light of the first photoelectric controller 32 is turned on and a "ready for injection" signal is issued; when the movable end of the injection bellows push tube 31 is pushed and extended by the booster compressed air to the plane side of the gas sample chamber 3, the infrared light of the second photoelectric controller 33 is blocked and a "end of injection" signal is issued.

[0052] Furthermore, the chromatograph 4 includes a programmable logic controller 41 , an input end of the programmable logic controller 41 is connected to the gas pipeline 2 , and an output end of the programmable logic controller 41 is connected to the chromatograph 4 .

[0053] The method for using the highly repeatable oil chromatography gas sample automatic injection device of this embodiment comprises the following steps:

[0054] Sample preparation;

[0055] Connect the chromatograph 4 and the gas sample chamber 3 via a connector 17;

[0056] The sample gas to be measured is input into the syringe 16;

[0057] Connect the syringe 16 and the gas sample chamber 3;

[0058] Start the programmable logic controller 41;

[0059] Start the pressurized air pump 11 to inject a specified amount of compressed air into the gas sample chamber 3;

[0060] The vacuum pump 15 is started to extract gas from the gas sample chamber 3 until the first photoelectric controller 32 is turned on and the second pressure controller 34 reaches the set value.

[0061] The working power switch QF1 is turned on to start the programmable logic controller 41 (PLC controller), and the programmable logic controller 41 enters the "injection preparation" state, and turns on the control relay 3J, closes the switch KM1, turns on the pressurized air pump 11 to fill the booster cylinder 13 with about 1.0 MPa of booster compressed air. When the first pressure controller 14 detects that the pressure in the booster cylinder 13 reaches the set value, the control relay 3J is disconnected, the switch KM1 is disconnected, and the pressurized air pump 11 is turned off. The programmable logic controller 41 turns on the control relays 5J and 6J, turns on the switch KM2, starts the vacuum pump 15, opens the third solenoid valve 37 and the three-way valve 22 (interface 2 and interface 3 are connected), and evacuates the gas sample chamber 3 and the injection bellows push tube 31. When the active end of the injection bellows push tube 31 is evacuated and shrinks to the first photoelectric controller 32, the infrared light signal emitted by the first photoelectric controller 32 is turned on, the three-way valve 22 (ports 2 and 3 are disconnected) is reset, and the injection bellows push tube 31 is ready. When the second pressure controller 34 detects that the vacuum negative pressure in the gas sample chamber 3 reaches the set value P1, the control relays 5J, 6J and the switch KM2 are disconnected, the third solenoid valve 37 is reset, the vacuum pump 15 stops evacuating, and the programmable logic controller 41 gives a voice alarm prompting that the injection can begin.

[0062] Inject gas sample;

[0063] Use the syringe 16 to input the test gas sample into the gas sample chamber 3;

[0064] Start the pressurized air pump 11 to deliver compressed air into the gas sample chamber 3, so that the bellows push tube 31 pushes the test gas sample to the connector 17;

[0065] The gas cylinder 12 is started, and the gas cylinder 12 releases the working carrier gas to push the detection gas sample into the chromatograph 4.

[0066] Insert the 5 ml syringe 16 containing the gas sample to be measured into the silicone pad connected to the gas injection port of the gas sample chamber 3 of the device with a double-ended needle, and quickly inject a certain volume of the gas sample to be measured in the syringe 16 into the gas sample chamber 3. After the gas sample to be measured is injected into the gas sample chamber 3, the second pressure controller 34 detects that the pressure in the gas sample chamber 3 rises from negative pressure P1 to positive pressure P2 by utilizing the expansion effect of the injected gas pressure, and triggers the injection operation signal to the programmable logic controller 41. At this time, the programmable logic controller 41 connects the control relays 1J, 4J, and the ports 1 and 3 of the three-way gas valve group, and simultaneously opens the first solenoid valve 21 at the front end of the gas sample chamber 3 and the three-way valve 22 (ports 1 and 3) at the front of the gas sample chamber 3, and the second solenoid valve 36 at the rear end of the gas sample chamber 3. At this time, the booster compressed air pressure inside the booster cylinder 13 is quickly released. Under the push of the compressed air pressure, the injection bellows push tube 31 in the gas sample chamber 3 expands and extends rapidly, and its movable end is pushed by the high-pressure airflow to move rapidly to the right, thereby pushing the measured gas sample in the gas sample chamber 3 into the connector 17, and then the working carrier gas output by the working carrier gas cylinder 12 sends it to the chromatograph 4 for analysis.

[0067] When the movable end of the injection bellows push tube 31 reaches the rightmost side of the gas sample chamber 3, the infrared light signal emitted by the second photoelectric controller 33 is blocked, and the programmable logic controller 41 disconnects the control relays 1J, 4J and ports 1 and 3 of the three-way gas circuit valve group, so that the first solenoid valve 21 at the front end of the gas sample chamber 3 and the three-way valve 22 (ports 1, 3) and the second solenoid valve 36 at the front of the gas sample chamber 3 are reset.

[0068] Gas sample chamber 3 removes residues;

[0069] Open the second connector and the third connector of the three-way valve 22, and open the third solenoid valve 37;

[0070] The vacuum pump 15 is started to extract the gas in the gas sample chamber 3 .

[0071] The programmable logic controller 41 will again control the relays 5J and 6J to turn on the switch KM2, start the vacuum pump 15, open the third solenoid valve 37 and the three-way valve 22 (ports 2 and 3 are connected), and evacuate the gas sample chamber 3 and the injection bellows push tube 31 to prepare for the next gas sample detection.

[0072] Prepare for injection again.

[0073] Through the above process, the highly repeatable automatic gas sample injection operation process including the device sample preparation, automatic gas sample injection, residual removal from the gas sample chamber 3, and re-preparation is completed.

[0074] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A highly repeatable oil chromatography gas sample automatic injection device, comprising a gas supply device, a gas pipeline (2), a gas sample chamber (3) and a chromatograph (4), wherein the gas supply device is connected to the gas sample chamber (3) through the gas pipeline (2), and the input end of the chromatograph (4) is connected to the gas sample chamber (3) through the gas pipeline (2), and the characteristic is that: The gas supply device comprises a pressurized air pump (11), a vacuum pump (15) and a syringe (16); the pressurized air pump (11) is connected to a first joint of a three-way valve (22) through an air pipeline (2); the second joint of the three-way valve (22) is connected to the vacuum pump (15); the third joint of the three-way valve (22) is connected to a driving air port of the gas sample chamber (3); the detection air port of the gas sample chamber (3) is connected to the syringe (16) and the chromatograph (4).

2. The highly repeatable oil chromatography gas sample automatic injection device according to claim 1, characterized in that: The gas supply device further comprises a gas cylinder (12) and a connector (17), wherein an input end of the connector (17) is connected to the gas cylinder (12) and a driving gas port of the gas sample chamber (3), and an output end of the connector (17) is connected to an input end of the chromatograph (4).

3. The highly repeatable oil chromatography gas sample automatic injection device according to claim 1, characterized in that: The output end of the pressurized air pump (11) is connected to the booster cylinder (13), the booster cylinder (13) is connected to the first pressure controller (14), and the output end of the booster cylinder (13) is connected to the driving air port of the gas sample chamber (3).

4. The highly repeatable oil chromatography gas sample automatic injection device according to claim 3, characterized in that: The output end of the boost cylinder (13) is connected to the first connector of the three-way valve (22) through a first solenoid valve (21); the pressurized air pump (11) is connected to the boost cylinder (13) through a one-way valve (23).

5. The highly repeatable oil chromatography gas sample automatic injection device according to claim 1, characterized in that: A bellows push tube (31) is arranged inside the gas sample chamber (3), one end of the bellows push tube (31) is fixed to the driving gas port of the gas sample chamber (3), and the other end of the bellows push tube (31) is slidably matched with the inner wall of the gas sample chamber (3); a first photoelectric controller (32) is arranged at the driving gas port end of the gas sample chamber (3), and a second photoelectric controller (33) is arranged at the detection gas port end of the gas sample chamber (3); a second pressure controller (34) and a third electromagnetic valve (37) are arranged in the middle of the gas sample chamber (3), and the third electromagnetic valve (37) is connected to the vacuum pump (15) through the gas pipeline (2); the detection gas port of the gas sample chamber (3) is connected to the gas delivery port (35) and the second electromagnetic valve (36) in sequence, the gas delivery port (35) is connected to the syringe (16), and the output end of the second electromagnetic valve (36) is connected to the connector (17).

6. The highly repeatable oil chromatography gas sample automatic injection device according to claim 1, characterized in that: The chromatograph (4) comprises a programmable logic controller (41), an input end of the programmable logic controller (41) is connected to the gas pipeline (2), and an output end of the programmable logic controller (41) is connected to the chromatograph (4).

7. A method for using a highly repeatable oil chromatography gas sample automatic injection device, characterized in that: A highly repeatable oil chromatography gas sample automatic injection device according to any one of claims 1 to 6, comprising the following steps: Sample preparation; Inject gas sample; The gas sample chamber (3) removes the residue; Prepare for injection again.

8. The method for using the highly repeatable oil chromatography gas sample automatic injection device according to claim 7, characterized in that: The sample preparation comprises the following steps: Connecting the chromatograph (4) and the gas sample chamber (3) via a connector (17); The sample gas to be measured is input into the syringe (16); Connecting the syringe (16) and the gas sample chamber (3); Starting a programmable logic controller (41); Starting the pressurized air pump (11) to inject a specified amount of compressed air into the gas sample chamber (3); The vacuum pump (15) is started to extract gas from the gas sample chamber (3) until the first photoelectric controller (32) is turned on and the second pressure controller (34) reaches the set value.

9. The method for using a highly repeatable oil chromatography gas sample automatic injection device according to claim 7, characterized in that: The injecting gas sample comprises the following steps: Using a syringe (16) to input a test gas sample into the gas sample chamber (3); The pressurized air pump (11) is started to deliver compressed air into the gas sample chamber (3), so that the bellows push tube (31) pushes the test gas sample to the connector (17); The gas cylinder (12) is started, and the gas cylinder (12) releases the working carrier gas to push the test gas sample into the chromatograph (4).

10. The method for using the highly repeatable oil chromatography gas sample automatic injection device according to claim 7, characterized in that: The gas sample chamber (3) removes the residues and comprises the following steps: Open the second connector and the third connector of the three-way valve (22), and open the third solenoid valve (37); The vacuum pump (15) is started to extract the gas in the gas sample chamber (3).

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