Cleaning device for gas chromatography sampling system

Abstract

The invention discloses a cleaning device for a gas chromatography sample introduction system, the cleaning device comprises a three-way pipe, a heating mechanism, a purging mechanism, a cleaning mechanism and a PLC controller, the three-way pipe comprises a sample introduction pipe, a sample discharge pipe and a cleaning pipe, the cleaning pipe is provided with a first electric butterfly valve, the heating mechanism comprises a first heating pipe and a second heating pipe, the first heating pipe is provided with a first electric butterfly valve, and the second heating pipe is provided with a second electric butterfly valve. Heating assemblies are arranged on the outer walls of the first heating pipe and the second heating pipe, the purging mechanism comprises a high-pressure nitrogen tank, the high-pressure nitrogen tank is communicated with a main gas pipe, an electromagnetic pulse valve is arranged on the main gas pipe, the main gas pipe is communicated with the interiors of a sample inlet pipe, a sample outlet pipe and a cleaning pipe through three branch pipes, and the cleaning mechanism comprises a peristaltic pump communicated with the cleaning pipe. The peristaltic pump is communicated with a main liquid pipe, the main liquid pipe is communicated with a plurality of liquid storage tanks through a plurality of branch liquid pipes, first electromagnetic valves are arranged on the plurality of branch liquid pipes, and the peristaltic pump, the electromagnetic pulse valve, the first electric butterfly valve and the plurality of first electromagnetic valves are electrically connected with a PLC (Programmable Logic Controller) respectively; the sample cleaning device integrates multiple sample cleaning functions.

Description

Technical Field

[0001] The invention relates to the technical field of chemical instrument cleaning, in particular to a cleaning device for a gas chromatography injection system. Background Art

[0002] In fields such as environmental monitoring, food safety, and petrochemicals, gas chromatography requires processing samples containing high-boiling-point additives, polymer residues, or oils and fats. These samples, after high-pressure injection, tend to form residual films in tubing and valves, which are difficult to completely remove. These residues can cause baseline drift, ghost peak interference, and decreased column performance, severely impacting quantitative accuracy.

[0003] Prior art methods for cleaning high-pressure gas chromatography injection systems primarily rely on gas purging. However, high-boiling-point samples can easily form residues in the injection line and injection valve assembly, making complete removal difficult with nitrogen purging alone. Furthermore, traditional cleaning methods lack the ability to tailor the cleaning strategy to sample characteristics, resulting in low cleaning efficiency. Therefore, a cleaning device that can efficiently remove high-boiling-point residues and achieve automated control is urgently needed. To this end, we propose a cleaning device for gas chromatography injection systems. Summary of the Invention

[0004] The problem to be solved by the present invention is how to efficiently clean chemical residues at the inlet of a gas chromatograph.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a cleaning device for a gas chromatography injection system, comprising a three-way pipe, a heating mechanism, a purge mechanism, a cleaning mechanism and a PLC controller, wherein the three-way pipe comprises an injection pipe, an outlet pipe and a cleaning pipe that are interconnected, and a first electric butterfly valve is provided at the intersection of the injection pipe and the outlet pipe on the cleaning pipe, the heating mechanism comprises a first heating pipe and a second heating pipe that are respectively connected to the injection pipe and the outlet pipe, and the outer walls of the first heating pipe and the second heating pipe are respectively provided with heating components, and the purge mechanism It includes a high-pressure nitrogen tank, which is connected to the main air pipe. The main air pipe is provided with an electromagnetic pulse valve. The main air pipe is connected to the inside of the sample inlet pipe, the sample outlet pipe and the cleaning pipe through three branch pipes respectively. The cleaning mechanism includes a peristaltic pump whose liquid outlet is connected to the cleaning pipe. The liquid inlet of the peristaltic pump is connected to the main liquid pipe. The main liquid pipe is connected to multiple liquid storage tanks through multiple branch pipes. The multiple branch pipes are respectively provided with a first electromagnetic valve. The peristaltic pump, electromagnetic pulse valve, first electric butterfly valve and multiple first electromagnetic valves are respectively electrically connected to the PLC controller.

[0006] As a preferred solution of the cleaning device for a gas chromatography injection system described in the present invention, a second electric butterfly valve is provided at one end of the first heating tube, a third electric butterfly valve is provided at one end of the second heating tube, and the second electric butterfly valve and the third electric butterfly valve are electrically connected to the PLC controller respectively.

[0007] As a preferred solution of the cleaning device for a gas chromatography injection system described in the present invention, the heating assembly includes a shell that is sleeved on the outer walls of the first heating tube and the second heating tube, and the outer walls of the first heating tube and the second heating tube are respectively wound with electric heating wires.

[0008] As a preferred solution of the cleaning device for a gas chromatography injection system described in the present invention, the power input end of the electric heating wire is electrically connected to the relay, the relay is electrically connected to the PLC controller, and the inner walls of the first heating tube and the second heating tube are respectively provided with a first temperature sensor and a second temperature sensor, and the first temperature sensor and the second temperature sensor are respectively electrically connected to the PLC controller.

[0009] As a preferred solution of the cleaning device for a gas chromatography injection system described in the present invention, the first heating tube, the second heating tube, and the tee tube are all made of stainless steel, a drain pipe is provided at the junction of the injection tube, the outlet tube and the cleaning tube, and a second solenoid valve is provided on the drain pipe, and the second solenoid valve is electrically connected to the PLC controller.

[0010] As a preferred solution of the cleaning device for a gas chromatography injection system described in the present invention, the three branch pipes respectively pass through the top of the injection pipe, the sample outlet pipe and the cleaning pipe, and the two branch pipe ends located above the inside of the injection pipe and the sample outlet pipe are respectively connected to the two sides of the top of the first blowing member, the first blowing member is a semi-cylindrical structure and the interior is set to be hollow, and the outer wall of the first blowing member is evenly distributed with multiple first blowing holes.

[0011] As a preferred solution of the cleaning device for a gas chromatography injection system described in the present invention, the end of the branch pipe located above the interior of the cleaning tube is connected to the top of the second blowing piece, the second blowing piece is a semi-cylindrical structure and the interior is hollow, and the outer wall of the second blowing piece is evenly distributed with multiple second blowing holes.

[0012] The beneficial effects of the present invention are as follows: the present invention integrates three functions of heating, solvent cleaning and nitrogen purging. The cleaning mechanism can use corresponding solvents and corresponding temperatures to clean according to different samples, so as to dissolve the samples in the solvent to the maximum extent. The nitrogen pulse purging is performed by the purging mechanism to drain the samples dissolved in the solvent through the drain pipe, thereby solving the problems of cross contamination, low efficiency and human error in the traditional method in the analysis of complex samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them: Figure 1 It is an overall intuitive diagram of the present invention.

[0014] Figure 2 This is an intuitive diagram from another perspective of the present invention.

[0015] Figure 3 Schematic diagram of the internal structure of the heating mechanism in the present invention.

[0016] Figure 4 It is a structural schematic diagram of the purge mechanism in the present invention. DETAILED DESCRIPTION

[0017] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is described in detail below with reference to the accompanying drawings.

[0018] Reference Figures 1 to 4 The present embodiment is a cleaning device for a gas chromatography injection system, comprising a three-way pipe 100, a heating mechanism 200, a purge mechanism 300, a cleaning mechanism 400 and a PLC controller. The three-way pipe 100 comprises an injection pipe 101, an outlet pipe 102 and a cleaning pipe 103 which are interconnected. The cleaning pipe 103 is provided with a first electric butterfly valve 103a near the intersection of the injection pipe 101 and the outlet pipe 102. The heating mechanism 200 comprises a first heating pipe 201 and a second heating pipe 202 which are respectively connected to the injection pipe 101 and the outlet pipe 102. The outer walls of the first heating pipe 201 and the second heating pipe 202 are respectively provided with a heating assembly 203. The purge mechanism 300 comprises a high-pressure nitrogen tank 300. 1. The high-pressure nitrogen tank 301 is connected to the main gas pipe 302, and an electromagnetic pulse valve 304 is provided on the main gas pipe 302. The main gas pipe 302 is connected to the interior of the sample inlet pipe 101, the sample outlet pipe 102 and the cleaning pipe 103 through three branch pipes 303 respectively. The cleaning mechanism 400 includes a peristaltic pump 401 whose liquid outlet is connected to the cleaning pipe 103. The liquid inlet of the peristaltic pump 401 is connected to the main liquid pipe 402, and the main liquid pipe 402 is connected to multiple liquid storage tanks 404 through multiple branch pipes 403. First electromagnetic valves 405 are respectively provided on the multiple branch pipes 403. The peristaltic pump 401, the electromagnetic pulse valve 304, the first electric butterfly valve 103a and the multiple first electromagnetic valves 405 are respectively electrically connected to the PLC controller.

[0019] The first electric butterfly valve 103a is controlled to be closed by the PLC controller, and the heating component 203 on the outer wall of the first heating tube 201 and the second heating tube 202 is controlled to be opened by the PLC controller. The heating component 203 can heat the sample passing through the first heating tube 201 and the second heating tube 202. The high temperature can reduce the viscosity of the sample. The sample is injected from the first heating tube 201, passes through the inlet tube 101 and the outlet tube 102 in the three-way tube 100, and is finally injected into the gas chromatograph for inspection by the second heating tube 202. Due to the closure of the first electric butterfly valve 103a, the sample can only enter the gas chromatograph but cannot enter the cleaning tube 103. After the sample injection is completed, the first electric butterfly valve 103a is controlled to be opened by the PLC controller, and the PLC controller controls the peristaltic pump 401 to be opened. The multiple liquid storage tanks 404 can contain different solvents, such as acetone solution, ethanol-acetone mixed solution, and methanol solution. The acetone solution can be used to clean heavy oil samples containing benzo(a)pyrene, and the ethanol-acetone mixed solution can be used to clean heavy oil samples containing benzo(a)pyrene. The combined solution can be used to clean the silicone oil suspension containing steroid hormones, and the methanol solution can be used to clean the benzene series containing α, α-dimethylbenzyl alcohol. According to the different samples, the corresponding liquid storage tank 404 is selected, the PLC controller controls the first solenoid valve 405 on the corresponding branch pipe 403 to open, and the peristaltic pump 401 pumps the solution in the liquid storage tank 404 into the three-way pipe 100, the first heating pipe 201 and the second heating pipe 202 for cleaning. The sample residue in the inner wall is continuously heated by the heating component 203 until it reaches the boiling point, where the sample residue can be better dissolved in the solvent and can be better cleaned. The solution mixed with the sample residue flows out from the first heating tube 201, and the PLC controller controls the opening of the electromagnetic pulse valve 304. The nitrogen in the high-pressure nitrogen tank 301 is pulse-purged through the electromagnetic pulse valve 304 to perform a secondary cleaning of the solution and sample residue in the three-way pipe 100, the first heating tube 201 and the second heating tube 202.

[0020] In this embodiment, a second electric butterfly valve 201a is provided at one end of the first heating tube 201, and a third electric butterfly valve 202a is provided at one end of the second heating tube 202. The second electric butterfly valve 201a and the third electric butterfly valve 202a are electrically connected to the PLC controller respectively.

[0021] When the sample needs to be injected into the gas chromatograph, the PLC controller controls the first electric butterfly valve 103a to close, and the second electric butterfly valve 201a and the third electric butterfly valve 202a to open. The sample passes through the first heating tube 201, the sample inlet tube 101, the sample outlet tube 102 and the second heating tube 202 in sequence. When solvent cleaning is required, the second electric butterfly valve 201a and the third electric butterfly valve 202a are closed, and the first electric butterfly valve 103a is opened to allow the solution to fill the three-way pipe 100, the first heating tube 201 and the second heating tube 202.

[0022] In this embodiment, the heating assembly 203 includes a shell 203a that is sleeved on the outer walls of the first heating tube 201 and the second heating tube 202. The outer walls of the first heating tube 201 and the second heating tube 202 are respectively wound with electric heating wires 203b.

[0023] In this embodiment, the power input end of the electric heating wire 203b is electrically connected to the relay, the relay is electrically connected to the PLC controller, and the inner walls of the first heating tube 201 and the second heating tube 202 are respectively provided with a first temperature sensor and a second temperature sensor, and the first temperature sensor and the second temperature sensor are respectively electrically connected to the PLC controller.

[0024] The PLC controller controls the relay to realize the power on and off operation of the electric heating wire 203b. The first temperature sensor in the first heating tube 201 can detect the heating temperature of the sample in the first heating tube 201, and the second temperature sensor in the second heating tube 202 can detect the temperature of the sample passing through the second heating tube 202. If the first temperature sensor detects that the sample temperature reaches the set temperature, the PLC controller controls the relay outside the second heating tube 202 to cut off the power to the electric heating wire 203b. If the first temperature sensor detects that the sample temperature does not reach the set temperature, the electric heating wire 203b on the outer wall of the second heating tube 202 continues to heat.

[0025] In this embodiment, the first heating tube 201, the second heating tube 202, and the three-way tube 100 are all made of stainless steel. A drain pipe 104 is provided at the junction of the sample inlet tube 101, the sample outlet tube 102 and the cleaning tube 103. A second solenoid valve 104a is provided on the drain pipe 104, and the second solenoid valve 104a is electrically connected to the PLC controller.

[0026] When the first heating tube 201, the second heating tube 202, and the three-way pipe 100 are filled with solution and need to be discharged, the PLC controller controls the second solenoid valve 104a on the discharge pipe 104 to open, and the solution mixed with the sample residue is discharged from the discharge pipe 104. Then the PLC controller controls the opening of the electromagnetic pulse valve 304, and the nitrogen in the high-pressure nitrogen tank 301 is pulsed through the electromagnetic pulse valve 304 for purging, and the residual solution and sample residue are discharged from the discharge pipe 104 along with the gas.

[0027] In this embodiment, the three branch pipes 303 pass through the top of the sample inlet tube 101, the sample outlet tube 102 and the cleaning tube 103 respectively. The ends of the two branch pipes 303 located above the inside of the sample inlet tube 101 and the sample outlet tube 102 are respectively connected to the two sides of the top of the first blowing member 305. The first blowing member 305 is a semi-cylindrical structure and the interior is set to be hollow. The outer wall of the first blowing member 305 is evenly distributed with multiple first blowing holes 305a.

[0028] In this embodiment, the end of the branch pipe 303 located above the inside of the cleaning pipe 103 is connected to the top of the second blowing member 306. The second blowing member 306 is a semi-cylindrical structure with a hollow interior. The outer wall of the second blowing member 306 is evenly distributed with multiple second blowing holes 306a.

[0029] The nitrogen in the high-pressure nitrogen tank 301 passes through the electromagnetic pulse valve 304 and then through the three branch pipes 303 to reach the first blow member 305 and the second blow member 306 respectively. Since the first blow member 305 and the second blow member 306 are both semi-cylindrical structures and are hollow inside, the nitrogen in the first blow member 305 is discharged through the multiple first blow holes 305a, and the nitrogen in the second blow member 306 is discharged through the multiple second blow holes 306a. The first blow member 305 and the second blow member 306 can discharge the nitrogen evenly and widely, so that the interior of the three-way pipe 100 can be purged everywhere.

[0030] Principle of use: When it is necessary to inject a sample into the gas chromatograph, the first electric butterfly valve 103a is closed and the second electric butterfly valve 201a and the third electric butterfly valve 202a are opened by the PLC controller. The PLC controller controls the relays outside the first heating tube 201 and the second heating tube 202 to energize the electric heating wire 203b for heating. The sample passes through the first heating tube 201, the sample inlet tube 101, the sample outlet tube 102 and the second heating tube 202 in sequence. Different heating temperatures and boiling points can be set according to the different characteristics of different samples. High temperature can reduce the viscosity of the sample. The first temperature sensor in the first heating tube 201 can detect the heating temperature of the sample in the first heating tube 201. The temperature in the second heating tube 202 can detect the heating temperature of the sample in the first heating tube 201. The second temperature sensor can detect the temperature of the sample passing through the second heating tube 202. If the first temperature sensor detects that the sample temperature has reached the set temperature, the PLC controller controls the relay outside the second heating tube 202 to cut off the power to the electric heating wire 203b. If the first temperature sensor detects that the sample temperature has not reached the set temperature, the electric heating wire 203b on the outer wall of the second heating tube 202 continues to heat. Due to the closure of the first electric butterfly valve 103a, the sample can only enter the gas chromatograph and cannot enter the cleaning tube 103. After the sample injection is completed, the PLC controller controls the first electric butterfly valve 103a to open, and controls the second electric butterfly valve 201a and the third electric butterfly valve 202a to close. The PLC controller controls the peristaltic pump 401 is opened, and multiple liquid storage tanks 404 can contain different solvents, such as acetone solution, ethanol-acetone mixed solution, and methanol solution. Acetone solution can be used to clean heavy oil samples containing benzo(a)pyrene, ethanol-acetone mixed solution can be used to clean silicone oil suspension containing steroid hormones, and methanol solution can be used to clean benzene series containing α, α-dimethylbenzyl alcohol. The corresponding liquid storage tank 404 is selected according to different samples, and the PLC controller controls the first solenoid valve 405 on the corresponding branch pipe 403 to open. The peristaltic pump 401 pumps the solution in the liquid storage tank 404 into the three-way pipe 100, the first heating pipe 201 and the second heating pipe 202 to clean the sample residue. The solvent is heated by the heating component 203 and adheres to the The sample residues in the inner walls of the three-way pipe 100, the first heating pipe 201 and the second heating pipe 202 are continuously heated by the heating component 203 until the boiling point is reached, so that the sample residues can be better dissolved in the solvent and can be better cleaned. When the first heating pipe 201, the second heating pipe 202 and the three-way pipe 100 are filled with solution and need to be discharged, the PLC controller controls the second solenoid valve 104a on the discharge pipe 104 to open, and the solution mixed with the sample residues is discharged from the discharge pipe 104. Then the PLC controller controls the opening of the electromagnetic pulse valve 304, and the nitrogen in the high-pressure nitrogen tank 301 passes through the electromagnetic pulse valve 304 and then through the three branch pipes 303 to reach the first blowing part 305 and the second blowing part 306 respectively.Because both the first blow piece 305 and the second blow piece 306 are semi-cylindrical structures with hollow interiors, the nitrogen in the first blow piece 305 is discharged through the multiple first blow holes 305a, and the nitrogen in the second blow piece 306 is discharged through the multiple second blow holes 306a. The first blow piece 305 and the second blow piece 306 can discharge the nitrogen evenly and widely, so that the entire interior of the three-way pipe 100 is subjected to the pulse purge effect, and the residual solution and sample residue are discharged through the drain pipe 104 along with the nitrogen.

[0031] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A cleaning device for a gas chromatography injection system, characterized in that: The invention comprises a three-way pipe (100), a heating mechanism (200), a purge mechanism (300), a cleaning mechanism (400) and a PLC controller, wherein the three-way pipe (100) comprises an inlet pipe (101), an outlet pipe (102) and a cleaning pipe (103) which are interconnected, and a first electric butterfly valve (103a) is provided on the cleaning pipe (103) near the intersection of the inlet pipe (101) and the outlet pipe (102). The heating mechanism (200) comprises a first heating pipe (201) and a second heating pipe (202) which are respectively connected to the inlet pipe (101) and the outlet pipe (102), and a heating assembly (203) is provided on the outer wall of the first heating pipe (201) and the second heating pipe (202). The purge mechanism (300) comprises a high-pressure nitrogen tank (301), and the high-pressure nitrogen tank (301) is connected to the main The main air pipe (302) is connected to the main air pipe (302), and an electromagnetic pulse valve (304) is provided on the main air pipe (302). The main air pipe (302) is connected to the inside of the sample inlet pipe (101), the sample outlet pipe (102) and the cleaning pipe (103) respectively through three branch pipes (303). The cleaning mechanism (400) includes a peristaltic pump (401) whose liquid outlet is connected to the cleaning pipe (103). The liquid inlet of the peristaltic pump (401) is connected to the main liquid pipe (402). The main liquid pipe (402) is connected to multiple liquid storage tanks (404) through multiple branch pipes (403). The multiple branch pipes (403) are respectively provided with a first electromagnetic valve (405). The peristaltic pump (401), the electromagnetic pulse valve (304), the first electric butterfly valve (103a) and the multiple first electromagnetic valves (405) are respectively electrically connected to the PLC controller.

2. A cleaning device for a gas chromatography injection system according to claim 1, characterized in that: A second electric butterfly valve (201a) is provided at one end of the first heating tube (201), and a third electric butterfly valve (202a) is provided at one end of the second heating tube (202); the second electric butterfly valve (201a) and the third electric butterfly valve (202a) are electrically connected to a PLC controller, respectively.

3. A cleaning device for a gas chromatography injection system according to claim 2, characterized in that: The heating assembly (203) comprises a shell (203a) sleeved on the outer walls of a first heating tube (201) and a second heating tube (202), and the outer walls of the first heating tube (201) and the second heating tube (202) are respectively wound with electric heating wires (203b).

4. A cleaning device for a gas chromatography injection system according to claim 3, characterized in that: The power input end of the electric heating wire (203b) is electrically connected to a relay, and the relay is electrically connected to a PLC controller. The inner walls of the first heating tube (201) and the second heating tube (202) are respectively provided with a first temperature sensor and a second temperature sensor, and the first temperature sensor and the second temperature sensor are respectively electrically connected to the PLC controller.

5. The cleaning device for a gas chromatography injection system according to claim 1, characterized in that: The first heating tube (201), the second heating tube (202), and the three-way tube (100) are all made of stainless steel. A drainage tube (104) is provided at the intersection of the sample inlet tube (101), the sample outlet tube (102), and the cleaning tube (103). A second solenoid valve (104a) is provided on the drainage tube (104). The second solenoid valve (104a) is electrically connected to the PLC controller.

6. The cleaning device for a gas chromatography injection system according to claim 1, characterized in that: The three branch pipes (303) pass through the top of the sample inlet pipe (101), the sample outlet pipe (102) and the cleaning pipe (103) respectively. The ends of the two branch pipes (303) located above the inside of the sample inlet pipe (101) and the sample outlet pipe (102) are respectively connected to the two sides of the top of the first blowing member (305). The first blowing member (305) is a semi-cylindrical structure and is hollow inside. The outer wall of the first blowing member (305) is evenly distributed with a plurality of first blowing holes (305a).

7. A cleaning device for a gas chromatography injection system according to claim 6, characterized in that: The end of the branch pipe (303) located above the inside of the cleaning pipe (103) is connected to the top of the second blowing member (306). The second blowing member (306) is a semi-cylindrical structure with a hollow interior. The outer wall of the second blowing member (306) is evenly distributed with a plurality of second blowing holes (306a).

Images