Self-cleaning ionization device

Abstract

The utility model provides a self-cleaning ionization device, which belongs to the technical field of volatile organic compound detection and single-photon ultraviolet lamp ionization source cleaning, and comprises a photoionization lamp, an ionization source, an ionization source, a cleaning device and a control device, and is characterized in that the photoionization lamp consists of a closed glass tube and an output light window on the surface of the glass tube; the inside of the ionization chamber is a through metal cavity, in the axial direction of the ionization chamber, one end of the ionization chamber is connected with the photoionization lamp, and the other end of the ionization chamber is connected with the mass analyzer; the cleaning reagent channels obliquely penetrate through the wall of the ionization chamber, outlets of the cleaning reagent channels point to the output light window, and extension lines of the cleaning reagent channels are converged on the central axis of the ionization chamber; and the cleaning carrier gas inlet and the cleaning carrier gas outlet are arranged between the photoionization lamp and the cleaning reagent channel, are respectively and vertically arranged on the side wall of the ionization chamber in a penetrating manner along the axial direction, and are symmetrically arranged.

Description

Technical Field

[0001] The utility model belongs to the technical field of volatile organic matter detection and single-photon ultraviolet lamp ionization source cleaning, and more specifically relates to a self-cleaning ionization device. Background Art

[0002] By exploring the cruise mode, using an online cruise monitoring system and analysis methods to monitor volatile organic compounds, the concentration distribution and change patterns of different volatile organic pollutants can be obtained in real time. The detection of volatile organic compounds (VOCs) in the cruise system often requires the use of a volatile organic mass spectrometer, which usually uses a single-photon ultraviolet lamp ionization source to ionize VOCs in the sample. Among them, the main structure of the single-photon ultraviolet lamp ionization source includes a photoionization (PID) lamp and an ionization chamber. The external sample is introduced into the ionization chamber through the injection tube. The ultraviolet photoelectrons generated by the PID lamp irradiate the volatile organic compounds in the ionization chamber, and single-photon ionization occurs to produce ions. The ions are subsequently transmitted to the detector for detection. During the actual navigation process, the external VOCs samples are relatively complex. When the gas to be tested flows through the ionization chamber, VOCs substances are easy to remain in the ionization chamber, and some pollutants are also brought into the ionization chamber during the flow of the gas to be tested and accumulated on the surface of the PID lamp. Various VOCs substances are attached to or contaminated inside the ionization device and the light source mirror of the PID lamp. The ionization efficiency of the contaminated PID lamp ion source decreases, resulting in the attenuation of the detection performance of the mass spectrometer.

[0003] Therefore, after the PID light ionization source is contaminated, the residual substances need to be removed before it can be used again to reduce the impact on the test results. It is inevitable to frequently and repeatedly clean the single-photon ultraviolet lamp ionization source of this structure during use. The conventional method for cleaning the contaminated surface of the PID light ionization source is to remove the PID light ionization source structure from the mass spectrometry system and perform external cleaning. In this process, it is necessary to shut down the mass spectrometry operating system, exhaust the mass spectrometry system to destroy the vacuum, and then open or disassemble some components of the mass spectrometry system to clean the contaminated ionization source. At the same time, use the corresponding abrasive or solvent for cleaning as needed, and then reinstall it in the mass spectrometry system after proper installation and adjustment. Although the conventional cleaning method can achieve the cleaning of the ion source, there are many problems, such as: professional technicians are required to go to the site to dismantle the ion source for cleaning, and the instrument needs to be debugged after the cleaned ion source is reinstalled to ensure that the ion source can work normally, resulting in a significant waste of operating time and affecting the detection efficiency of the sample. Utility Model Content

[0004] In view of the above technical problems, the present invention provides a self-cleaning ionization device, in order to at least partially solve the above technical problems. Therefore, the specific technical solutions provided by the present invention are as follows.

[0005] The utility model provides a self-cleaning ionization device, comprising: a photoionization lamp, comprising a closed glass tube and an output light window attached to the surface of the glass tube; an ionization chamber, the interior of which is a through metal cavity, and in the axial direction, has a photoionization lamp mounting end and a mass spectrometer connecting end located at the other end, wherein the photoionization lamp is mounted on the ionization lamp mounting end, the output light window is located on the central axis of the ionization chamber, and the mass spectrometer connecting end is connected to a mass analyzer of the mass spectrometer; a cleaning reagent channel, obliquely penetrating the wall of the ionization chamber, the outlets of the cleaning reagent channel on the inner wall of the ionization chamber all point to the output light window, and the extension lines of the inclined cleaning reagent channel converge on the central axis of the ionization chamber; and an air inlet and an air outlet for cleaning carrier gas, which are arranged between the photoionization lamp and the cleaning reagent channel, and the air inlet and the air outlet for cleaning carrier gas are respectively arranged on the side wall of the ionization chamber perpendicular to the axial direction and are symmetrically arranged.

[0006] In the embodiment of the utility model, while keeping the original ionization chamber structure unchanged, a cleaning reagent channel is set on the wall of the ionization chamber, and the outlets of the cleaning reagent channel are all directed to the output light window, and the extension lines of the inclined cleaning reagent channel are gathered on the central axis of the ionization chamber, so that the cleaning reagent can be used to clean the output light window and the inner wall of the ionization chamber at the same time. In addition, the cleaning reagent channel set obliquely can be more focused on cleaning the output light window during the cleaning process, and at the same time provide a certain cleaning impulse to improve the cleaning effect of the output light window. Further, an air inlet and an air outlet of the cleaning carrier gas are set between the photoionization lamp and the cleaning reagent channel, and the air inlet and the air outlet of the cleaning carrier gas are respectively set on the side wall of the ionization chamber perpendicular to the axial direction so that the cleaning carrier gas can be used to purge the cleaning reagent and the eluted volatile substances on the output light window and the surface of the ionization chamber; the air inlet and the air outlet of the cleaning carrier gas are designed to be symmetrically arranged so as to carry the volatile substances out of the ionization chamber. Accordingly, the output light window and the ionization chamber can be cleaned when the detection device is in standby mode without restoring the vacuum of the ionization chamber to the standard pressure. After the cleaning is completed, the detection device automatically returns to the pressure required for the detection state, saving time and effort. Furthermore, the self-cleaning ionization device provided by the utility model does not involve any disassembly process, reduces the requirements for cleaning personnel, saves the operation process and time of disassembly, installation, and debugging of the photoionization lamp, and improves the efficiency of detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a cross-sectional view of a self-cleaning ionization device in one embodiment of the utility model;

[0008] Figure 2 yes Figure 1 The overall structure diagram of the self-cleaning ionization device shown;

[0009] Figure 3 This is a comparison diagram of mass spectrometer detection before and after cleaning the output light window in one embodiment of the utility model.

[0010] [Description of Reference Numerals]

[0011] 1- photoionization lamp, 2- ionization chamber, 3- mass spectrometer, 4- reagent pump, 5- cleaning gas source tank, 6- valve, 101- glass tube, 102- output light window, 201- cleaning carrier gas inlet, 202- cleaning carrier gas outlet, 203- injection passage, 204- cleaning reagent channel, 301- mass analyzer. DETAILED DESCRIPTION

[0012] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0013] When the surface of the ionization source of the current volatile organic mass spectrometer is contaminated, it is necessary to shut down the mass spectrometry operating system, exhaust the mass spectrometry system to destroy the vacuum, and then manually open or disassemble some components of the mass spectrometry system to clean the contaminated ionization source and perform external cleaning, which is time-consuming and labor-intensive and requires professionals to disassemble and install. After cleaning, the instrument needs to be debugged to ensure its normal operation, which wastes operating time and affects sample detection efficiency.

[0014] In this regard, the utility model provides a self-cleaning ionization device, which achieves the cleaning effect of the ionization device by arranging a cleaning reagent channel, an air inlet and an air outlet for cleaning the carrier gas on the ionization chamber, and utilizing the cleaning reagent to react with the output light window of the photoionization lamp and the residual substances attached to the inner wall of the ionization chamber, thereby ensuring the continuous ionization stability of the instrument without disassembling and destroying the vacuum environment of the mass spectrometer.

[0015] Specifically, the utility model provides a self-cleaning ionization device, comprising: a photoionization lamp, comprising a closed glass tube and an output light window attached to the surface of the glass tube; an ionization chamber, the interior of which is a through metal cavity, and having a photoionization lamp mounting end and a mass spectrometer connecting end located at the other end in the axial direction of the ionization chamber, wherein the photoionization lamp is mounted on the ionization lamp mounting end, the output light window is located on the central axis of the ionization chamber, and the mass spectrometer connecting end is connected to the mass analyzer of the mass spectrometer; a cleaning reagent channel, obliquely penetrating the wall of the ionization chamber, the outlets of the cleaning reagent channel on the inner wall of the ionization chamber all point to the output light window, and the extension lines of the inclined cleaning reagent channel converge on the central axis of the ionization chamber; and an air inlet and an air outlet for cleaning carrier gas, which are arranged between the photoionization lamp and the cleaning reagent channel, and the air inlet and the air outlet for cleaning carrier gas are respectively arranged on the side walls of the ionization chamber perpendicular to the axial direction and are symmetrically arranged.

[0016] In an embodiment of the utility model, while keeping the original ionization chamber structure unchanged, a cleaning reagent channel is provided on the wall of the ionization chamber, and an air inlet and an air outlet for the cleaning carrier gas are provided between the photoionization lamp and the cleaning reagent channel. Accordingly, the output light window and the ionization chamber can be cleaned when the detection device is in a standby state without restoring the vacuum degree of the ionization chamber to the standard air pressure. After the cleaning is completed, the detection device automatically returns to the air pressure required for the detection state, saving time and effort. Furthermore, the self-cleaning ionization device provided by the utility model does not involve any disassembly process, which reduces the requirements for cleaning personnel, saves the operating procedures and time for disassembly, installation, and debugging of the photoionization lamp, and improves the efficiency of detection.

[0017] Figure 1 is a cross-sectional view of a self-cleaning ionization device in one embodiment of the utility model; Figure 2 yes Figure 1 The overall structural diagram of the self-cleaning ionization device is shown.

[0018] like Figure 1-Figure 2 As shown, the self-cleaning ionization device provided by the utility model includes: a photoionization lamp 1, an ionization chamber 2, a mass spectrometer 3, a glass tube 101, an output light window 102, an air inlet 201 for cleaning carrier gas, an air outlet 202 for cleaning carrier gas, an injection passage 203, a cleaning reagent channel 204 and a mass analyzer 301.

[0019] The photoionization lamp (PID lamp) 1 is composed of a closed glass tube 101 and an output light window 102 attached to the surface of the glass tube 101. Further, the gas filling is selected according to the type and concentration of the volatile organic compound to be measured, and the closed glass tube 101 is filled with gas, wherein the filling gas can be selected from any inert gas among nitrogen, helium and argon. The output light window 102 is located on the central axis of the ionization chamber 2, and the ultraviolet photoelectrons generated by the photoionization lamp 1 are introduced from the output light window 102 of the photoionization lamp 1 and directed to the mass spectrometer 3 along the central axis of the ionization chamber 2.

[0020] The ionization chamber 2 is a cylindrical structure or other shapes, and its interior is a through metal cavity, which is constructed as an ionization and cleaning place. In the axial direction of the ionization chamber 2, there is a photoionization lamp mounting end and a mass spectrometer connection end located at the other end, wherein the photoionization lamp 1 is mounted on the photoionization lamp mounting end, and the mass spectrometer connection end is connected to the mass analyzer 301 of the mass spectrometer 3. The output light window 102 is located on the central axis of the ionization chamber 2 to introduce the ultraviolet light generated by the photoionization lamp 1 from the output light window 102 of the photoionization lamp 1 into the ionization chamber 2, and transmit it along the central axis of the ionization chamber 2 to the mass analyzer 301 of the mass spectrometer 3. In other words, the installation direction of the PID lamp 1 is axial to the ionization chamber 2, consistent with the ion transmission direction, and the ultraviolet light is introduced into the ionization chamber 2 from the end face of the ionization chamber 2 (i.e., the output light window 102).

[0021] An air inlet 201 for cleaning carrier gas, an air outlet 202 for cleaning carrier gas and a cleaning reagent channel 204 are arranged on the wall of the ionization chamber 2, wherein the air inlet 201 and the air outlet 202 for cleaning carrier gas are arranged between the photoionization lamp 1 and the cleaning reagent channel 204, and close to the output light window 102 of the photoionization lamp 1, so as to effectively purge the volatile organic matter and cleaning reagent attached to the output light window 102, and at the same time carry the cleaned volatile organic matter and cleaning reagent out of the ionization chamber 2. Specifically, the cleaning reagent channel 204 is inclined to penetrate the wall of the ionization chamber 2, and the outlets of the cleaning reagent channel 204 on the inner wall of the ionization chamber 2 are all directed to the output light window 102, and the extension lines of the inclined cleaning reagent channel 204 converge on the central axis of the ionization chamber 2, so as to use the cleaning reagent to clean the output light window and the inner wall of the ionization chamber at the same time, and the inclined design helps to focus more on cleaning the output light window during the cleaning process, and at the same time provides a certain cleaning impulse to improve the cleaning effect of the output light window. There may be one or more cleaning reagent channels 204, and the inclination angle (α) of the cleaning reagent channels 204 is 40-70°, where α is the angle between the cleaning reagent channels 204 and the vertical direction of the central axis of the ionization chamber 2. In the case where there are multiple cleaning reagent channels 204, the multiple cleaning reagent channels 204 are arranged in a circle around the ionization chamber 2 to ensure that each position of the inner wall of the ionization chamber 2 can contact the cleaning reagent, thereby improving the cleaning effect. In addition, the multiple cleaning reagent channels 204 can be loaded with the same or different cleaning reagents. When the multiple cleaning reagent channels 204 are loaded with different cleaning reagents, different cleaning reagents can be controlled to be introduced into the ionization chamber 2 at the same time or in steps, so as to clean different types of volatile organic compounds or to perform step-by-step cleaning on the same type of volatile organic compounds, thereby improving the cleaning efficiency and effect. The cleaning reagent is a solvent that can dissolve volatile organic compounds, such as methanol, ethanol, and acetone. The inlet 201 and outlet 202 of the cleaning carrier gas are respectively arranged on the side wall of the ionization chamber 2 perpendicularly to the axial direction of the ionization chamber 2, and are arranged symmetrically, so as to fully carry the cleaning reagents and volatile organic compounds in the ionization chamber 2 out of the ionization chamber 2. The inlet 201 and outlet 202 of the cleaning carrier gas can be one pair or more pairs, and the multiple pairs of the inlet 201 and outlet 202 of the cleaning carrier gas are arranged in a circle around the outer wall of the ionization chamber 2 to ensure that every position of the inner wall of the ionization chamber 2 can be purged by the carrier gas, so as to effectively purge the volatile organic compounds and cleaning reagents, and ensure that there is no cleaning reagent and volatile organic compounds remaining in the ionization chamber 2, wherein the cleaning carrier gas can be any inert gas among nitrogen, helium, and argon, and the cleaning carrier gas can be consistent with the protective gas in the mass spectrometer.

[0022] Further, continue as Figure 2As shown, the self-cleaning ionization device provided by the utility model further includes: an injection passage 203. The injection passage 203 is vertically penetrated and arranged on the side wall of the ionization chamber 2. Further, the injection passage 203 is located between the output light window 102 and the inlet 201 and the outlet 202 of the cleaning carrier gas. The external sample is introduced into the cavity of the ionization chamber 2 through the injection passage, and is irradiated by the ultraviolet light emitted by the output light window 102 to be fully ionized to form ion fragments.

[0023] Furthermore, continue as Figure 1 and Figure 2 As shown, the self-cleaning ionization device provided by the utility model also includes at least one of the following components: a reagent pump 4, a cleaning gas source storage tank 5 and a valve 6. The reagent pump 4 is connected to the entrance of the cleaning reagent channel 204 to transport the cleaning reagent into the ionization chamber 2 for cleaning work. The amount and flow rate of the cleaning reagent entering the ionization chamber 2 can be controlled by controlling the flow rate of the reagent pump 4. The cleaning gas source storage tank 5 is connected to the air inlet 201 of the cleaning carrier gas to provide the cleaning carrier gas. The cleaning carrier gas can be any inert gas among nitrogen, helium and argon, and the cleaning carrier gas can be consistent with the protective gas in the mass spectrometer. The valve 6 is arranged between the cleaning gas source storage tank 5 and the air inlet 201 of the cleaning carrier gas to control the flow rate of the cleaning carrier gas. The cleaning carrier gas can enter the ionization chamber 2 through the vacuum degree in the ionization chamber 2, and be discharged from the ionization chamber 2 by the pressure of the air outlet of the cleaning carrier gas.

[0024] Specifically, the following combination Figure 1-Figure 2 The cleaning process of the self-cleaning ionization device in the utility model is briefly described, wherein methanol is selected as the cleaning reagent and argon is used as the cleaning carrier gas.

[0025] When the mass spectrometer stops detecting, the cleaning reagent (methanol reagent) is introduced into the ionization chamber 2 through the cleaning reagent channel 204, and the photoionization lamp 1 is not turned on. The cleaning reagent and the volatile organic matter attached to the inner wall of the ionization chamber 2 and the output light window 102 of the photoionization lamp 1 undergo a dissolution-desorption reaction, and the volatile organic matter after the reaction is desorbed from the attachment surface to form a volatile substance. The cleaning carrier gas (argon gas) is introduced into the inlet 201 of the cleaning carrier gas, and the desorbed volatile organic matter and the cleaning reagent are carried out of the ionization chamber 2 from the outlet 202 of the cleaning carrier gas. Alternatively, during the cleaning process, when the volatile organic matter contacts the methanol solvent, the volatile organic matter is adsorbed and dissolved in the methanol cleaning reagent. The photoionization lamp 1 is turned on to increase the temperature in the ionization chamber 2, accelerate the dissociation and release of the dissolved volatile organic matter from the methanol cleaning reagent, and is carried away by the cleaning carrier gas, thereby improving the purge efficiency. Furthermore, during the cleaning process, the cleaning reagent and the cleaning carrier gas are alternately introduced into the ionization chamber 2, so that the cleaning reagent reacts with the volatile organic matter and is promptly purged out of the ionization chamber 2 by the cleaning carrier gas, and the cleaning process is repeated, so that the volatile organic matter is thoroughly cleaned and the residue of the cleaning reagent is avoided. After the cleaning is completed, the instrument can be used normally directly (such as Figure 3 The entire cleaning process can be carried out in the standby state of the mass spectrometer under normal vacuum pumping. Compared with conventional manual cleaning, which requires stopping the vacuum and cleaning under atmospheric pressure, the self-cleaning ionization device provided by the utility model saves time and labor, and significantly shortens the downtime of the mass spectrometer; at the same time, the entire cleaning process is simple to operate, and no additional disassembly and assembly process is required, which reduces the requirements for cleaning personnel.

[0026] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A self-cleaning ionization device, characterized in that: The device comprises: A photoionization lamp comprises a sealed glass tube and an output light window attached to the surface of the glass tube; An ionization chamber, the interior of which is a through metal cavity, having a photoionization lamp mounting end in the axial direction and a mass spectrometer connecting end at the other end, wherein the photoionization lamp is mounted on the photoionization lamp mounting end, the output light window is located on the central axis of the ionization chamber, and the mass spectrometer connecting end is connected to a mass analyzer of the mass spectrometer; a cleaning reagent channel obliquely penetrating the wall of the ionization chamber, wherein the outlets of the cleaning reagent channel on the inner wall of the ionization chamber are all directed toward the output light window, and the extension lines of the inclined cleaning reagent channel converge on the central axis of the ionization chamber; and The inlet and outlet of the cleaning carrier gas are arranged between the photoionization lamp and the cleaning reagent channel. The inlet and outlet of the cleaning carrier gas are respectively arranged on the side wall of the ionization chamber perpendicular to the axial direction and are symmetrically arranged.

2. The device according to claim 1, characterized in that The device also includes: The sample inlet passage is vertically penetrated and arranged on the side wall of the ionization chamber.

3. The device according to claim 2, characterized in that The injection passage is arranged between the output light window and the gas inlet and gas outlet of the cleaning carrier gas.

4. The device according to claim 1 or 2, characterized in that: The inlet and outlet of the cleaning carrier gas are one pair or more pairs, and the multiple pairs of the inlet and outlet of the cleaning carrier gas are arranged in a circle around the outer wall of the ionization chamber.

5. The device according to claim 4, characterized in that There are one or more cleaning reagent channels, and the inclination angle of the cleaning reagent channels is 40-70°.

6. The device according to claim 5, characterized in that In the case where the cleaning reagent channel is a plurality of cleaning reagent channels, the plurality of cleaning reagent channels are arranged in a circle around the ionization chamber, and the plurality of cleaning reagent channels are loaded with the same or different cleaning reagents.

7. The device according to claim 1, characterized in that Also includes: A reagent pump is connected to the inlet of the cleaning reagent channel.

8. The device according to claim 1 or 7, characterized in that Also includes: The cleaning gas source storage tank is connected to the gas inlet of the cleaning carrier gas.

9. The device according to claim 8, characterized in that Also includes: The valve is arranged between the cleaning gas source storage tank and the gas inlet of the cleaning carrier gas.

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