CN113189258A - Photoionization measurement device and method - Google Patents

Photoionization measurement device and method Download PDF

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Publication number
CN113189258A
CN113189258A CN202110640121.2A CN202110640121A CN113189258A CN 113189258 A CN113189258 A CN 113189258A CN 202110640121 A CN202110640121 A CN 202110640121A CN 113189258 A CN113189258 A CN 113189258A
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gas
collecting
photoionization
electrode
measured
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谢雷
杨雁南
沈飞宙
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Shanghai Leimi Sensing Technology Co ltd
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Shanghai Leimi Sensing Technology Co ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N30/62—Detectors specially adapted therefor
    • G01N30/64—Electrical detectors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N30/62—Detectors specially adapted therefor
    • G01N30/64—Electrical detectors
    • G01N2030/642—Electrical detectors photoionisation detectors

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Abstract

The present application relates to a photoionization measurement device and method, the photoionization measurement device of the present application includes: the ionization chamber, the light-emitting component, the measuring chamber and the detection component; the ionization chamber is configured to enable light rays emitted by the light emitting component to be emitted into the ionization cavity so as to ionize the gas to be measured in the ionization cavity; the measuring chamber is provided with an outlet hole passage penetrating through the measuring chamber, and the outlet hole passage is communicated with the ionization cavity so that ionized gas to be measured flows out; the detection assembly comprises a collecting electrode and a bias electrode which are electrically connected and used for detecting the ionized gas to be detected in the outlet pore canal. Therefore, the method and the device have selectivity, can be used for measuring the gas to be measured in a targeted manner, and improve the accuracy of measurement of the gas to be measured.

Description

Photoionization measurement device and method
Technical Field
The application relates to the field of detectors, in particular to a photoionization measuring device and method.
Background
In the prior art, a Photo Ionization Detector (PID for short) has no selectivity, and cannot be used for measuring a gas to be measured in a targeted manner, so that the accuracy of measuring the gas to be measured is improved. For example: when the gas to be measured is the mixed gas of benzene and toluene, the prior art cannot distinguish benzene from toluene and cannot select only to measure benzene.
Disclosure of Invention
The purpose of the application is to provide a photoionization measurement device and method, which have selectivity, can pertinently measure the gas to be measured, and improve the accuracy of measuring the gas to be measured.
In order to achieve the above-mentioned objects,
in a first aspect, the present application provides a photoionization measurement device comprising: the device comprises an ionization chamber, a light-emitting component, a measuring chamber, a voltage controller, a flow controller and a detection component; the light-emitting component is used for emitting light; the ionization chamber is provided with an ionization cavity for containing gas to be measured, and the ionization chamber is configured to enable light rays emitted by the light-emitting component to be emitted into the ionization cavity so as to ionize the gas to be measured in the ionization cavity; the measuring chamber is provided with an outlet hole passage penetrating through the measuring chamber, and the outlet hole passage is communicated with the ionization cavity so that ionized gas to be measured flows out; the detection assembly comprises a collecting electrode and a bias electrode which are electrically connected and used for detecting the gas to be detected after ionization in the outlet pore canal, and the voltage controller is electrically connected with the detection assembly and used for controlling the voltage of the detection assembly.
In a second aspect, the present application provides a photoionization measurement method, which is applied to the above photoionization measurement device, and the photoionization measurement method includes: acquiring the response sensitivity of the collecting electric block to different components in the gas to be detected; acquiring response current of the collecting electric block; and calculating to obtain the component concentration information of the gas to be detected according to the response sensitivity of the collecting electric block to different components in the gas to be detected and the response current of the collecting electric block.
Compared with the prior art, the beneficial effect of this application is: this application has the selectivity, can aim at ground to the gas that awaits measuring, has improved the accuracy of the gas measurement that awaits measuring, for example when the gas that awaits measuring is benzene and toluene gas mixture, and prior art can't distinguish benzene and toluene, can't select only to measure benzene, and this application can select only to measure benzene, also can select only to measure toluene, can also measure simultaneously and obtain benzene concentration and toluene concentration in this gas mixture. The interference of the environment humidity to the gas measurement can be deducted, and the accuracy of the gas measurement to be measured is improved. This application is through setting up a plurality of electric pieces of collecting to can utilize a plurality of electric pieces of collecting to measure the content of different components in the gas that awaits measuring in the response sensitivity difference of different components in the gas that awaits measuring, carry out qualitative and quantitative analysis to complicated gas composition that awaits measuring, distinguish various compositions in the gas that awaits measuring.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.
Fig. 1 is an exploded view of a photoionization measurement device according to an embodiment of the present application.
Fig. 2 is a top view of a photoionization measurement device according to an embodiment of the present disclosure.
Fig. 3 is a cross-sectional view of a photoionization measurement device according to an embodiment of the present application.
Fig. 4 is a perspective view of a measurement chamber according to an embodiment of the present application.
FIG. 5 is a front view of a measurement chamber shown in an embodiment of the present application.
FIG. 6 is a cross-sectional view of a measurement chamber shown in an embodiment of the present application.
Fig. 7 is a perspective view of a photoionization measurement device according to an embodiment of the present application.
Fig. 8 is a top view of a photoionization measurement device according to an embodiment of the present application.
Fig. 9 is a cross-sectional view of a photoionization measurement device according to an embodiment of the present application.
Fig. 10 is a cross-sectional view of a photoionization measurement device according to an embodiment of the present application.
Fig. 11 is a perspective view of a photoionization measurement device according to an embodiment of the present application.
Fig. 12 is a perspective view of a photoionization measurement device according to an embodiment of the present application.
Fig. 13 is a top view of a photoionization measurement device according to an embodiment of the present application.
Fig. 14 is a cross-sectional view of a photoionization measurement device according to an embodiment of the present application.
Fig. 15 is a cross-sectional view of a photoionization measurement device according to an embodiment of the present application.
Icon: 100-photoionization measurement device; 200-an ionization chamber; 210-an ionization chamber; 210 a-an inner top wall of the ionization chamber; 210 b-the outer side wall of the ionization chamber; 210 c-the outer top wall of the ionization chamber; 210 d-an outer bottom wall of the ionization chamber; 220-installing a step hole; 300-a light emitting assembly; 310-an ultraviolet lamp; 400-a measurement chamber; 410-an outlet port; 411-the upper inner wall of the duct; 412-lower inner wall of tunnel; 413-tunnel annular sidewall; 500-a detection component; 510-a collecting electrode; 511-collecting the electric block; 512-a first spacer; 520-a bias electrode; 521-a first opening; 522-shade member; 650-inlet pipe; 700-a voltage controller; 800-flow controller.
Detailed Description
The terms "first," "second," "third," and the like are used for descriptive purposes only and not for purposes of indicating or implying relative importance, and do not denote any order or order. Furthermore, the terms "horizontal", "vertical", "overhang" and the like do not imply that the components are required to be absolutely horizontal or overhang, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined. In the description of the present application, it should be noted that the terms "inside", "outside", "left", "right", "upper", "lower", and the like indicate orientations or positional relationships based on orientations or positional relationships shown in the drawings or orientations or positional relationships that are conventionally arranged when products of the application are used, and are used only for convenience in describing the application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the application. In the description of the present application, unless expressly stated or limited otherwise, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements.
The technical solution of the present application will be clearly and completely described below with reference to the accompanying drawings.
Fig. 1 is an exploded view of a photoionization measurement device 100 according to an embodiment of the present disclosure. A photoionization measurement device 100 includes: the ionization chamber 200, the light emitting component 300, the measuring chamber 400, the detecting component 500 and the inlet tube 650, wherein the measuring chamber 400 is tubular and has an outlet channel 410 penetrating through the measuring chamber 400, and the outlet channel 410 can be a straight channel or a curved channel. The inlet pipe 650 may be a straight pipe or a bent pipe.
The light emitting assembly 300 is disposed on the outer bottom wall 210d of the ionization chamber, the inlet tube 650 and the measuring chamber 400 are disposed on the outer side wall 210b of the ionization chamber, and the inlet tube 650 and the measuring chamber 400 are disposed opposite to each other and located on the left and right sides of the ionization chamber 200. In one embodiment, the axis of the inlet tube 650 and the axis of the measurement chamber 400 are coincident, and the axis of the ionization chamber 200 and the axis of the measurement chamber 400 are perpendicular.
The inlet tube 650, the measuring chamber 400 and the ionization chamber 200 may be integrally formed, or may be connected together by bolting, welding, etc.
The detection assembly 500 includes a collecting electrode 510 and a bias electrode 520 electrically connected to each other for detecting the ionized gas to be detected in the outlet channel 410. The collecting electrode 510 and the biasing electrode 520 are both of a unitary structure and are disposed on the inner wall of the outlet channel 410 in an opposing arrangement. Wherein, the collecting electrode 510 is a cathode for receiving positive ions formed after the gas to be measured is ionized, and the collecting electrode 510 with an integral structure can be called as a collecting electrode block 511; the bias electrode 520 is an anode for receiving electrons and/or negative ions formed after the gas to be measured is ionized. A first deflecting electric field may be formed between the collecting electrode 510 and the biasing electrode 520 to facilitate detection.
The photoionization measurement device 100 further includes: the voltage controller 700 is electrically connected to the detecting assembly 500, and is configured to control a voltage of the detecting assembly 500, where the voltage controller 700 may control a collecting voltage between the collecting electrode 510 and the bias electrode 520 to be constant, or may regulate the collecting voltage between the collecting electrode 510 and the bias electrode 520 to reach a specified voltage value. In one embodiment, the voltage controller 700 may further include a voltage sensor for detecting a voltage.
The photoionization measurement device 100 further includes: the flow controller 800, the flow controller 800 is a gas flow controller, and is disposed on the outlet port 410 for controlling the flow of the gas to be measured.
The voltage controller 700 may be directly disposed in the photoionization measurement device 100, or may be external, and the flow controller 800 may be directly disposed in the photoionization measurement device 100, or may be external.
In one embodiment, the photoionization measurement device 100 further includes a control center including a communicator, a memory, a processor, and a human-computer interaction component for controlling the voltage controller 700 and the flow controller 800. In an embodiment, the control center may further include a humidity sensor disposed in the ionization chamber 200 for detecting the humidity of the gas to be detected; the control center may further include at least one current sensor coupled to the sensing assembly 500 for sensing current.
In one operation, the organic gas to be measured is brought into the ionization chamber 200 from the inlet tube 650, the organic gas to be measured is dissociated into electrons and organic cations in the ionization chamber 200 under the irradiation of the ultraviolet light emitted by the light emitting device 300, the electrons and the organic cations are brought into the measurement chamber 400 along with the gas flow of the organic gas to be measured, the electrons and the organic cations in the gas flow are deflected under the action of the first deflecting electric field, the positive ions flow toward the collecting electrode 510, the electrons flow toward the biasing electrode 520, thereby forming a signal current, and the signal current is amplified and measured in the detection circuit in the detection device 500, and the measured gas is discharged from the outlet port 410 of the measurement chamber 400.
The present embodiment has selectivity, the voltage controller 700 controls the voltage change of the detection assembly 500, and the flow controller 800 controls the flow of the gas to be detected to be constant, so that the gas to be detected can be measured in a targeted manner, and the accuracy of the measurement of the gas to be detected is improved.
In another embodiment, the photoionization measurement device is not provided with the flow controller 800, and the gas to be measured is directly introduced at a constant speed.
In another operation process, the voltage controller 700 controls the voltage of the detecting element 500 to be constant, and the flow controller 800 controls the flow rate of the gas to be detected to be changed.
In addition, the detection assembly 500 is partially or completely disposed in the measurement chamber 400, and the light irradiated to the surface of the detection assembly 500 is partially or completely shielded by physical isolation, so that the risk of damage to the detection assembly 500 due to long-term irradiation of the light emitted by the light emitting assembly 300 is reduced, the service life of the detection assembly 500 can be prolonged, and the measurement accuracy is improved.
Fig. 2 is a top view of a photoionization measurement device 100 according to an embodiment of the present disclosure. Fig. 3 is a cross-sectional view of a photoionization measurement device 100 according to an embodiment of the present disclosure. The light emitting assembly 300 may include an ultraviolet lamp 310 for emitting light; the ionization chamber 200 has an ionization chamber 210 for accommodating a gas to be measured, and the ionization chamber 200 is configured to enable light emitted by the light emitting element 300 to be emitted into the ionization chamber 210, so as to ionize the gas to be measured in the ionization chamber 210. The gas to be measured may be a gas sample containing Volatile Organic Compounds (VOCs), among others.
In this embodiment, the ionization chamber 200, the measurement chamber 400, and the inlet tube 650 are integrally formed in a pipe structure, the ionization chamber 200 is hollow cylindrical, the measurement chamber 400 and the inlet tube 650 are square pipes, and the axial length of the measurement chamber 400 is greater than the axial length of the inlet tube 650. The outer bottom wall 210d of the ionization chamber is provided with a mounting step hole 220 penetrating through the outer bottom wall 210d of the ionization chamber, and the light emitting end of the light emitting assembly 300 is mounted in the mounting step hole 220, so that the light emitted by the light emitting assembly 300 can be emitted into the ionization chamber 210 by using the mounting step hole 220. In this case, the ionization chamber 200, the measurement chamber 400, and the inlet tube 650 may be made of a material having light-shielding properties, such as opaque plastic, or may be made of a material having light-transmitting properties, such as glass or transparent plastic. A sealing ring may be disposed between the mounting stepped hole 220 and the light emitting assembly 300 to prevent the gas to be measured from leaking.
In another embodiment, the ionization chamber 200 is made of a transparent material such as glass or transparent plastic. The light emitting device 300 is disposed outside the ionization chamber 200 and does not extend into the ionization chamber 200, so that the light emitted from the light emitting device 300 can be emitted into the ionization chamber 210 by utilizing the light transmittance of the ionization chamber 200.
In another embodiment, the mounting step hole 220 is provided with a light-transmitting member such as a light-transmitting film by means of clamping or adhering, and the whole light-emitting device 300 is disposed outside the ionization chamber 200 and does not extend into the ionization chamber 200, so that the light emitted from the light-emitting device 300 can be emitted into the ionization chamber 210 by using the light-transmitting member.
The outlet channel 410 is communicated with the ionization chamber 210 to allow the ionized gas to be measured to flow out. The outlet duct 410 is a straight duct transversely disposed, the outlet duct 410 is a cylindrical or square duct, and the axial direction of the outlet duct 410 intersects with the direction of the light emitted by the light emitting assembly 300. In this embodiment, the axial direction of the outlet duct 410 is the left-right direction, and the direction of the light emitted by the light emitting assembly 300 is upward. The axial direction of the outlet duct 410 is perpendicular to the direction of the light emitted from the light emitting assembly 300.
The inner wall of the outlet duct 410 includes an upper duct inner wall 411 and a lower duct inner wall 412 which are oppositely arranged, the upper duct inner wall 411 and the duct are respectively provided with a mounting groove, the collecting electrode 510 is located below the offset electrode 520, the collecting electrode 510 is embedded in the mounting groove of the lower duct inner wall 412, and the offset electrode 520 is embedded in the mounting groove of the upper duct inner wall 411, so that the offset electrode 520 and the collecting electrode 510 are oppositely arranged up and down.
In the present embodiment, the detecting elements 500 are all disposed in the measuring chamber 400, so that the measurement of the gas to be measured all occurs in the measuring chamber 400, and the measurement of the gas to be measured occurs after the ionization process, thereby improving the accuracy of the measurement. In addition, the detection assembly 500 is disposed in the measurement chamber 400, and the light irradiated to the surface of the detection assembly 500 is completely shielded by physical isolation, so that the risk of damage to the detection assembly 500 due to long-term irradiation of the light emitted by the light emitting assembly 300 is reduced, and the baseline noise interference is reduced, thereby prolonging the service life of the detection assembly 500 and improving the measurement accuracy.
Fig. 4 is a perspective view of a measurement chamber 400 according to an embodiment of the present disclosure. Referring to fig. 5, a front view of a measuring chamber 400 is shown according to an embodiment of the present disclosure. Referring to fig. 6, a cross-sectional view of a measurement chamber 400 according to an embodiment of the present disclosure is shown. The measuring chamber 400 and the ionization chamber 200 are of a split structure and can be connected together in a bolt connection mode, a welding mode or a plug-in connection mode and the like, and a sealing ring can be arranged at the connecting position of the measuring chamber 400 and the ionization chamber 200 to prevent air leakage.
The measuring chamber 400 is a square tube structure, the collecting electrode 510 is located above the bias electrode 520, the collecting electrode 510 is attached to the upper inner wall 411 of the pore channel by means of adhesion, and the bias electrode 520 is attached to the lower inner wall 412 of the pore channel by means of adhesion or embedding. The measuring chamber 400 is a cuboid structure, the outlet channel 410 is also a cuboid structure, and the transverse cross-sectional size of the collecting electrode 510, the transverse cross-sectional size of the offset electrode 520, the size of the upper inner wall 411 of the channel and the size of the lower inner wall 412 of the channel are the same.
Fig. 7 is a perspective view of a photoionization measurement device 100 according to an embodiment of the present application. Fig. 8 is a top view of a photoionization measurement device 100 according to an embodiment of the present disclosure. Fig. 9 is a cross-sectional view of a photoionization measurement device 100 according to an embodiment of the present disclosure. The collecting electrode 510 includes a plurality of collecting electrode blocks 511 arranged at intervals, and a first separator 512 is interposed between adjacent two collecting electrode blocks 511. The first isolation member 512 is made of an insulating material such as plastic or rubber, and is used for isolating the two adjacent collecting electrode blocks 511. Therefore, in the embodiment, by providing the plurality of collecting electric blocks 511, the content of different components in the gas to be measured can be measured by utilizing the difference of the response sensitivity of the plurality of collecting electric blocks 511 to different components in the gas to be measured.
The collecting electrode 510 is located below the biasing electrode 520, the collecting electrode 510 and the first spacer 512 are embedded in the mounting groove of the lower inner wall 412 of the channel, and the biasing electrode 520 is embedded in the mounting groove of the upper inner wall 411 of the channel.
In this embodiment, the collecting electrode block 511 and the first separator 512 are each in a rectangular parallelepiped shape. The width of the collecting electrode block 511 is greater than the width of the first partition 512, the height of the collecting electrode block 511 is equal to the height of the first partition 512, and the length of the collecting electrode block 511 is equal to the length of the first partition 512.
The collecting electrode blocks 511 are provided in two, and the first separator 512 is provided in one. The axial length of the measurement chamber 400 is less than the axial length of the inlet tube 650. The first spacer 512 is made of Polytetrafluoroethylene (PTFE). Here, when there are two collecting electrode blocks 511, the voltage controller 700 may be provided with two, respectively controlling the voltage between the bias electrode 520 and the two collecting electrode blocks 511.
Fig. 10 is a cross-sectional view of a photoionization measurement device 100 according to an embodiment of the present application. In this embodiment, five collecting electrodes 510 are provided, and four first separators 512 are provided. The axial length of the measurement chamber 400 is greater than the axial length of the inlet tube 650. The light emitting device 300 is disposed on the outer bottom wall 210d of the ionization chamber, the measurement chamber 400 has an outlet channel 410 penetrating through the measurement chamber 400, the inlet tube 650 and the measurement chamber 400 are both disposed on the outer sidewall 210b of the ionization chamber, and the inlet tube 650 and the measurement chamber 400 are disposed opposite to each other and respectively located on the left and right sides of the ionization chamber 200.
Fig. 11 is a perspective view of a photoionization measurement device 100 according to an embodiment of the present application. The light emitting assembly 300 is disposed on the outer bottom wall 210d of the ionization chamber, the inlet tube 650 is disposed on the outer side wall 210b of the ionization chamber, the measuring chamber 400 is disposed on the outer top wall 210c of the ionization chamber, and the measuring chamber 400 and the light emitting assembly 300 are respectively disposed on the upper and lower sides of the ionization chamber 200. The axis of the inlet tube 650 and the axis of the measuring chamber 400 are vertically arranged, and the axis of the ionization chamber 200 and the axis of the measuring chamber 400 are coincidently arranged. The axial length of the inlet tube 650 and the axial length of the measuring chamber 400 may be equal or different, and in this embodiment, the axial length of the inlet tube 650 is greater than the axial length of the measuring chamber 400.
Fig. 12 is a perspective view of a photoionization measurement device 100 according to an embodiment of the present application. The axial length of the inlet tube 650 is less than the axial length of the measurement chamber 400.
Fig. 13 is a top view of a photoionization measurement device 100 according to an embodiment of the present disclosure. Fig. 14 is a cross-sectional view of a photoionization measurement device 100 according to an embodiment of the present disclosure. The outlet duct 410 is a vertically arranged square straight duct, and the axial direction of the outlet duct 410 is longitudinal (up-down), and is arranged in the same direction as the light emitted by the light emitting assembly 300.
The outlet duct 410 is provided with a fillet, and the inner wall of the outlet duct 410 is integrally a duct annular side wall 413; an annular mounting groove is formed on the tunnel annular side wall 413, and the collecting electrode block 511 and the first isolating piece 512 of the collecting electrode 510 are embedded in the mounting groove of the tunnel annular side wall 413. In this embodiment, since the collecting electrode block 511 and the first isolating member 512 are embedded, the ultraviolet radiation of the ultraviolet lamp 310 on the collecting electrode block 511 and the first isolating member 512 can be reduced, and the risk of damage to the detecting assembly 500 due to long-term radiation of light can be reduced.
In this embodiment, the collecting electrode block 511 and the first separator 512 are both annular sheet-shaped. The radial section of the outlet port 410 is a rounded rectangle, the width of the collecting electrode block 511 is equal to the width of the first separator 512, the length of the collecting electrode block 511 is equal to the length of the first separator 512, and the height of the collecting electrode block 511 is greater than the height of the first separator 512. The collecting electrode blocks 511 are provided in two, and the first separator 512 is provided in two.
The inner wall of the ionization chamber 210 includes an inner top wall 210a of the ionization chamber, and the biasing electrode 520 is disposed on the inner top wall 210a of the ionization chamber such that the biasing electrode 520 can be relatively far away from the light emitting assembly 300. The biasing electrode 520 is provided with at least one first opening 521 for communicating the outlet port 410 with the ionization chamber 210. In this embodiment, the bias electrode is a ring-shaped plate, and the radial cross-sectional area of the bias electrode is larger than that of the collecting electrode block 511.
The photoionization measurement device 100 further includes: the light shielding member 522 is disposed between the light emitting device 300 and the bias electrode 520, and the light shielding member 522 is attached or adhered to the bias electrode 520 for shielding light irradiated onto the surface of the bias electrode 520. The light-shielding member 522 may be made of a material capable of shielding ultraviolet light. The light shielding member 522 has the same shape and size as the bias electrode 520, and is an annular perforated plate.
In this embodiment, the radial cross section of the first opening 521 is smaller, the radial cross section of the outlet duct 410 is larger, and the aperture of the first opening 521 is smaller than that of the outlet duct 410, so that the light shielding member 522 can shield the light irradiated to the surface of the collecting electrode 510 as well as the light irradiated to the surface of the bias electrode 520.
In this embodiment, the collecting electrode 510 is located in the measuring chamber 400, and the bias electrode 520 is located on the inner top wall 210a of the ionization chamber far away from the light emitting device 300, so that the detecting device 500 is partially disposed in the measuring chamber 400, and thus the measurement of the gas to be measured partially occurs in the measuring chamber 400, and the measurement of the gas to be measured occurs after the ionization process as much as possible, thereby improving the accuracy of the measurement. In addition, the detection assembly 500 is partially disposed in the measurement chamber 400, and the light shielding member 522 is disposed to physically isolate or completely shield the light irradiated to the surface of the detection assembly 500, so as to reduce the risk of damage to the detection assembly 500 due to long-term irradiation of the light emitted by the light emitting assembly 300, thereby prolonging the service life of the detection assembly 500 and improving the accuracy of measurement.
Fig. 15 is a cross-sectional view of a photoionization measurement device 100 according to an embodiment of the present application. The collecting blocks 511 are provided with five, and the first partition 512 is provided with five.
In a second aspect, the present application provides a photoionization measurement method, which can be applied to a control center of a photoionization measurement device 100, and the specific principle of the photoionization measurement method is as follows:
as shown in fig. 5 and 6, the width of the transverse cross section of the outlet channel 410, the width of the transverse cross section of the collecting electrode 510 and the width of the transverse cross section of the biasing electrode 520 are all a, the length of the transverse cross section of the outlet channel 410, the length of the transverse cross section of the collecting electrode 510 and the length of the transverse cross section of the biasing electrode 520 are all L, and the distance between the collecting electrode 510 and the biasing electrode 520 and the height of the outlet channel 410 are all d. The time required for the gas to be measured to pass through the outlet orifice 410 of the measurement chamber 400 can be calculated using equation (1):
Figure BDA0003106082700000131
wherein τ is the time required for the gas to be measured to pass through the outlet orifice 410 of the measurement chamber 400; f is the gas flow; V-adL is the volume of outlet port 410; ad is the cross-sectional area of the outlet duct 410 in the direction perpendicular to the gas flow.
The field strength E of the electric field generated between the collecting electrode 510 and the biasing electrode 520 can be calculated by equation (2):
Figure BDA0003106082700000132
where U is the voltage applied between the collecting electrode 510 and the biasing electrode 520; d is the distance between the collecting electrode 510 and the bias electrode 520.
The charged ions i include cations generated by ionization of the gas to be measured, and after the charged ions i are introduced into the measurement chamber 400 from the ionization chamber 200, the charged ions i are shifted under the action of the electric field generated between the collecting electrode 510 and the biasing electrode 520, not all the ions are collected by the collecting electrode 510, wherein the charged ions i are collected by the collecting electrode 510 for the required time tiPerpendicular to the charged ions i after entering the measurement chamber 400 and the collecting electrode 510The distance is related.
The time t required for the charged ions i to be collected by the collecting electrode 510iThe calculation can be performed using equation (3):
Figure BDA0003106082700000133
wherein m isiThe mass of charged ions i in the gas to be measured; q. q.siThe charged quantity of the charged ions i; u is the voltage applied between the collecting electrode 510 and the bias electrode 520, yiThe perpendicular distance of the charged ions i from the collecting electrode 510.
As can be seen from equation (3), the time required for the charged ions i near the collecting electrode 510 to be collected by the collecting electrode 510 is short, and the time required for the charged ions i far from the collecting electrode 510 to be collected is long. When the charged ions i are at a vertical distance y from the collecting electrode 510iIs equal to the distance d between the collecting electrode 510 and the biasing electrode 520, i.e. yiWhen d, the time t required for the charged ions i to be collected by the collecting electrode 510 isiThe longest.
The maximum time required for the charged ions i to be collected by the collecting electrode 510 is less than the time τ required for the gas to be measured to pass through the outlet channel 410 of the measurement chamber 400, i.e., the time τ
Figure BDA0003106082700000141
At this time, all the charged ions i entering the measurement chamber 400 are collected by the collecting electrode 510, and the collecting electrode 510 has the highest collecting efficiency and the highest sensitivity.
When the maximum time required for the charged ions i to be collected by the collecting electrode 510 is longer than the time τ required for the gas to be measured to pass through the outlet channel 410 of the measuring chamber 400, i.e., the time τ
Figure BDA0003106082700000142
At this time, only a part of the charged ions i entering the measuring chamber 400 is collected by the collecting electrode 510, and at this time, only the charged ions i are vertically spaced from the collecting electrode 510 by the vertical distance yiSatisfy the requirement of
Figure BDA0003106082700000143
Is collected, and the charged ions i are at a perpendicular distance y from the collecting electrode 510iSatisfy the requirement of
Figure BDA0003106082700000144
Is not collected.
The ion proportion of the charged ions i collected according to the above relationship can be calculated by using equation (4):
Figure BDA0003106082700000145
wherein R isiIs the proportion of charged ions i collected by the collecting electrode 510; y isi(τ) is the maximum distance charged ion i can be collected by collecting electrode 510 from the electrode; m isiThe mass of charged ions i in the gas to be measured; q. q.siThe charged quantity of the charged ions i; u is the voltage applied between the collecting electrode 510 and the bias electrode 520, yiThe perpendicular distance of the charged ions i from the collecting electrode 510.
R can be obtained from the formula (4)iIn relation to the mass-to-charge ratio of the charged ions i, the flow rate of the gas to be measured, the collection voltage applied to the detection module 500, and the electrode structure design of the photoionization measurement device 100, under the condition that the structure of the photoionization measurement device 100 is fixed, the charged ions i with different mass-to-charge ratios are collected at different ratios on the collection electrode 510, so that the charged ions i with smaller mass-to-charge ratios are collected more, and the charged ions i with larger mass-to-charge ratios are collected less.
The following conditions are satisfied in equation (4): (1) ionization chamber 200 is separated from measurement chamber 400 in photoionization measurement device 100; (2) the gas to be measured sequentially flows through the ionization chamber 200 and the measurement chamber 400 at a fixed flow rate; (3) the bias electrode 520 and the collecting electrode 510 are both vertical to the airflow direction of the gas to be measured; (4) the sizes of the structures of the bias electrode 520 and the collecting electrode 510 can be designed according to the characteristics of the gas to be measured; (5) the voltage between the bias electrode 520 and the collecting electrode 510 can be adjusted according to the characteristics of the gas to be measured.
Accordingly, under the condition that the structural design of the fixed photoionization measurement device 100 and the gas flow are fixed and unchanged, and only one set of the collecting electrode 510 and the bias electrode 520 (one collecting electrode block 511 and one bias electrode, such as the structures of fig. 1 to 6) is provided, the gas to be measured can be measured for multiple times by adjusting the voltage of the collecting electrode 510, under the condition of different collecting voltages, the response sensitivity of the electrode to ions with different mass-to-charge ratios is different, a plurality of response equations can be obtained, then the concentrations of different components in the mixed gas are solved through simultaneous equations, and the selective measurement of the target gas in the complex gas environment is realized. On the premise that the collection voltage is fixed, multiple sets of bias electrodes 520 and collection electrodes 510 (multiple collection blocks 511 and one bias electrode stage, such as the structures of fig. 7-15) can be used for measurement, so as to solve the concentration of different gases in the mixed gas and realize selective measurement of the target gas in the complex gas environment.
Therefore, the photoionization measurement method can selectively measure the VOC gas according to the characteristics and can also measure the contents of different components in the mixed gas.
In one embodiment, the photoionization measurement method includes the steps of:
step S110: the response sensitivity of the collecting electrode block 511 to different components in the gas to be measured is obtained.
Step S120: acquiring the response current of the collecting block 511;
step S130: and calculating to obtain the component concentration information of the gas to be measured according to the response sensitivity of the collecting electric block 511 to different components in the gas to be measured and the response current of the collecting electric block 511.
In the above steps S110 to S130, when there is one collecting electrode block 511, the response sensitivity in step S110 is the response sensitivity of the collecting electrode block 511 to different components in the gas to be measured at different collecting voltages; the response current in step S120 is the response current of the collecting block 511 at different collecting voltages. When a plurality of collecting electrodes 511 are provided, the response sensitivity in step S110 is the response sensitivity of each collecting electrode 511 to different components in the gas to be measured; the response current in step S120 is the response current of each collecting block 511.
In one embodiment, when one collecting electrode 511 is provided, the photoionization measurement method includes the following steps:
step S210: the response sensitivities of the collecting electrode blocks 511 to different components in the gas to be measured under different collecting voltages are respectively obtained.
Step S220: response currents of the collecting electric blocks 511 at different collecting voltages are respectively obtained.
Step S230: and calculating to obtain the component concentration information of the gas to be measured according to the response sensitivity of the collecting electric block 511 to different components in the gas to be measured under different collecting voltages and the response current of the collecting electric block 511 under different collecting voltages.
The above steps S210 to S230 will be described by taking the measurement of the mixed gas of benzene and toluene as an example.
When the apparatus of the embodiment shown in fig. 1-6 is used, first a first collecting voltage U1 (collecting voltage, i.e. voltage applied to collecting electrode 510) is applied between collecting electrode 510 (one collecting electrode block 511) and bias electrode 520 by voltage controller 700, and benzene ions are collected by collecting electrode 510 entirely at first collecting voltage U1, while toluene ions are collected only partially:
IU1＝kU1CC6H6+KU1CC7H8 (5)
wherein, IU1To collect the response current of electrode 510 at a first collection voltage U1, kU1To collect the response sensitivity of electrode 510 to benzene at a first collection voltage U1, KU1To collect the response sensitivity of electrode 510 to toluene at a first collection voltage U1, CC6H6Is the concentration of benzene in the gas to be measured, CC7H8Is the concentration of toluene in the gas to be measured.
The voltage of the collecting electrode 510 is then adjusted by the voltage controller 700 to a second collecting voltage U2, at which the collecting electrode 510 completely collects both benzene and toluene ions:
IU2＝kU2CC6H6+KU2CC7H8 (6)
wherein, IU2To collect the response current of electrode 510 at a second collection voltage U2, kU2Is at the firstResponse sensitivity, K, of collecting electrode 510 to benzene at two collecting voltages U2U2To collect the response sensitivity of electrode 510 to toluene at a second collection voltage U2, CC6H6Is the concentration of benzene in the gas to be measured, CC7H 8Is the concentration of toluene in the gas to be measured.
In this example, the benzene and toluene concentrations can be determined by simultaneous equations (5) and (6), respectively.
In the present example, the response sensitivity in step S210 refers to k in formula (5) and formula (6)U1、KU1、kU2And KU2，kU1、KU1、kU2And KU2Are known parameters or can be obtained by measurement, experiment or calculation in advance. The response current in step S220 refers to I in formula (5) and formula (6)U1And IU2，IU1And IU2May be measured during operation by a sensing means such as a current sensor. The component concentration information of the gas to be measured in step S230 refers to C in formula (5) and formula (6)C6H6And CC7H8. The first collecting voltage U1 and the second collecting voltage U2 are known parameters and can be obtained by measurement, experiment or calculation by applying formula (4) in advance.
In one embodiment, when there are a plurality of collecting electrode blocks 511, the method for measuring photoionization includes the following steps:
step S310: the response sensitivity of each collecting electrode block 511 to different components in the gas to be measured is obtained respectively.
Step S320: the response current of each collecting electrode block 511 is acquired respectively.
Step S330: and calculating to obtain the component concentration information of the gas to be measured according to the response sensitivity of each collecting electric block 511 to different components in the gas to be measured and the response current of each collecting electric block 511.
The above-mentioned step S310 to step S330 will be described by taking the measurement of the mixed gas of benzene and toluene as an example.
When the device of the embodiment shown in fig. 7-9 is employed, the voltage controller 700 controls the collecting voltage between the collecting electrode 510 and the bias electrode 520 to be constant. Two kinds of cations generated after benzene and toluene in the mixed gas are ionized by the ultraviolet lamp 310 are captured by the collecting electrode 510 (two collecting electric blocks 511), but the response sensitivity is different, and the collecting electric block 511 on the left side and the collecting electric block 511 on the right side satisfy the relation:
I301＝k301CC6H6+K301CC7H8 (7)
I302＝k302CC6H6+K302CC7H8 (8)
wherein, I301The response current, k, of the collecting block 511 on the left301Sensitivity of the left collecting electrode block 511 to the benzene, K301The sensitivity of the collecting electrode block 511 to toluene, CC6H6To measure the benzene concentration in the gas, CC7H8To determine the concentration of toluene in the gas I302Is the response current, k, of the collecting electrode block 511 on the right302The response sensitivity, K, of the right collecting electrode block 511 to the benzene302The response sensitivity of the right collecting electrode block 511 to toluene.
In this example, since two collecting electrode blocks 511 in the collecting electrode 510 capture part of benzene and toluene ions respectively, but the capturing ratio is different, the ion amount of the gas to be measured after reaching the collecting electrode block 511 on the right side changes to different degrees, which is represented as k302And K302The ratio is varied in different ways, so that the concentrations of benzene and toluene can be determined by simultaneous equations (7) and (8).
In the present example, the response sensitivity in step S310 refers to k in formula (7) and formula (8)301、K301、k302And K302，k301、K301、k302And K302The known parameters can be obtained by measurement, experiment or calculation in advance. The response current in step S320 refers to I in formula (7) and formula (8)301And I302，I301And I302May be measured during operation by a sensing means such as a current sensor. The component concentration information of the gas to be measured in step S330 refers to C in formula (7) and formula (8)C6H6And CC7H8. The constant collection voltage controlled by the voltage controller 700 is a known parameter and can be obtained by measuring, testing or calculating by applying the formula (4) in advance.
In an alternative embodiment, the cross-sectional area of the left collector block 511 can be designed to be large enough to fully capture benzene ions, but only partially capture toluene ions, where k is302The benzene has no effect on the measurement of the collecting electrode block 511 on the right side, where the content of the different components in the mixed gas can be measured more easily and better. Here, the cross-sectional area of the left collecting electrode block 511 can be calculated by applying equation (4).
In another embodiment, the larger the number of collecting electrode blocks 511, the more complex the mixture gas can be measured, for example, the device of the embodiment shown in FIG. 10 can be used.
In one embodiment, since the gas component that has an influence on the measurement and is present in the mixture gas also has humidity, in order to effectively compensate for the humidity interference, the photoionization measurement method includes the following steps:
step S410: the response sensitivity of each collecting electrode block 511 to different components in the gas to be measured is obtained respectively.
Step S420: the response current of each collecting electrode block 511 is acquired respectively.
Step S430: and respectively obtaining the response correction coefficient of each collecting electric block 511 to the humidity of the gas to be measured.
Step S440: and calculating to obtain the component concentration information of the gas to be measured according to the humidity value of the gas to be measured, the response sensitivity of each collecting electric block 511 to different components in the gas to be measured and the response current of each collecting electric block 511.
The above steps S410 to S440 will be described by taking the measurement of isobutene gas as an example.
When the apparatus of the embodiment shown in fig. 9 is used for measuring isobutylene gas of various humidities, the voltage controller 700 controls the collecting voltage between the collecting electrode 510 and the bias electrode 520 to be constant. Wherein, the response of the left collecting electric block 511 and the right collecting electric block 511 to the isobutene and the humidity satisfies the relationship:
I301＝k301CC4H8+k301RHRH (9)
I302＝k302CC4H8+k302RHRH (10)
wherein, I301The response current, k, of the collecting block 511 on the left301Sensitivity of the collecting electrode block 511 on the left to the response of isobutene, k301RHThe response correction coefficient, I, of the left collecting electrode block 511 to humidity302Is the response current, k, of the collecting electrode block 511 on the right302The response sensitivity, k, of the right collecting electrode block 511 to isobutene302RHThe response correction coefficient of the right collecting electrode block 511 to the humidity, RH is the relative humidity value of the gas to be measured, CC4H8Is the isobutene concentration.
In this example, RH in the formula (9) and the formula (10) may be a known parameter or an unknown parameter, and when RH is an unknown parameter, interference of humidity on measurement may be subtracted by the simultaneous equations (9) and (10) in this example, and component concentration information of the gas to be measured is obtained through calculation. When RH is a known parameter or a measurable parameter, in this example, the interference of humidity on measurement can be deducted through equation (9) or equation (10), and the component concentration information of the gas to be measured is calculated.
In the present example, the response sensitivity in step S410 refers to k in formula (9) and formula (10)301And k302，k301And k302Are known parameters or can be obtained by measurement, experiment or calculation in advance. The response current in step S420 refers to I in formula (9) and formula (10)301And I302，I301And I302May be measured during operation by a sensing means such as a current sensor. The response correction coefficient in step S430 refers to k in equations (9) and (10)301RHAnd k302RH，k301RHAnd k302RHAre known parameters or can be obtained by measurement, experiment or calculation in advance. For example, the humidity can be calculated in advance by measuring gases with different humidities and then calculating the humidity from the measured values. Formation of gas to be measured in step S440The concentration information refers to C in formula (9) and formula (10)C4H8. The constant collection voltage controlled by the voltage controller 700 is a known parameter and can be obtained by measuring, testing or calculating by applying the formula (4) in advance.
In one embodiment, when one collecting electrode 511 is provided, the photoionization measurement method includes the following steps:
step S510: and response sensitivity of the collecting electric block 511 to different components in the gas to be detected when the gas to be detected with different flow rates is obtained respectively.
Step S520: and respectively acquiring response currents of the collecting electric blocks 511 aiming at the gas to be detected with different flow rates.
Step S530: and calculating to obtain the component concentration information of the gas to be detected according to the response sensitivity of the collecting electric block 511 to different components in the gas to be detected when aiming at the gas to be detected with different flow rates and the response current of the collecting electric block 511 to the gas to be detected with different flow rates.
In the above-mentioned processes of step S210 to step S530, the principle is similar to the formula (4), the formula (5) and the formula (6), and the component concentration of the gas to be measured can be obtained by simultaneous equations after a plurality of measurements.
For example, the following equations may be associated:
IF1＝kF1CC6H6+KF1CC7H8 (16)
IF2＝kF2CC6H6+KF2CC7H8 (17)
wherein C isC6H6The concentration of benzene in the gas to be measured; cC7H8The concentration of toluene in the gas to be measured; i isF1In order to collect the response current, k, of the electrical block 511 when passing the gas to be measured at the first flow rate F1F1In order to collect the response sensitivity, K, of the electrode block 511 to the benzene when the gas to be measured with the first flow rate F1 is introducedF1Respectively, the response sensitivity, I, of the collecting electrode block 511 to toluene when the gas to be measured with the first flow rate F1 is introducedF2In order to collect the response current, k, of the electrical block 511 when passing the gas to be measured at the first flow rate F2F2For collecting the electricity block 511 when the gas to be measured with the first flow rate F2 is introducedResponse sensitivity to benzene, KF2The sensitivity of the collecting electrode block 511 to the response of toluene when the gas to be measured is introduced at the first flow rate F2 is shown respectively.
It should be noted that, in the above example, the measurement is performed on the gas to be measured with a known composition, and when the unknown composition exists in the gas to be measured, the photoionization measurement method can still perform the measurement on the specified composition of the gas to be measured.
Now, by using the apparatus of the embodiment shown in fig. 3 and using the steps S210 to S230, the complex mixed gas components can be analyzed by means of voltage sweep.
Under different collection voltages, ions with different mass-to-charge ratios are collected by the collection electrodes 510 in different collection ratios, that is, under different collection voltages, the response sensitivities of the collection electrodes 510 to different ion components in the mixed gas are different, so that one voltage scanning is equivalent to carrying out countless measurement and analysis on the mixed gas, and theoretically, the components in the mixed gas can be qualitatively and quantitatively analyzed through analyzing a measurement map.
Determination of the measurement parameters of the photoionization measurement device 100: the foregoing analysis shows that, under the conditions determined by the structure of the photoionization measurement device 100 and the gas flow rate, the collection efficiency of ions with different collection voltages and different mass-to-charge ratios is different, and the collection efficiency of ions with small mass-to-charge ratios is higher. There is a characteristic voltage for ions of different mass to charge ratios at which the constituent ions can be fully collected by the collecting electrode 510. The characteristic voltages of the ions of the different gas components can be determined in advance by experiments.
First, when a mixed gas of ethanol, isobutylene, benzene and toluene with known concentrations was measured using the apparatus of the example shown in fig. 3, the characteristic voltages of ethanol, isobutylene, benzene and toluene were U1, U2, U3 and U4, respectively, which were obtained by voltage sweep analysis.
At characteristic voltage U1: the ethanol ions are completely trapped and the other ions are partially trapped.
At characteristic voltage U2: ethanol ions, isobutene ions are completely captured, and other ions are partially captured.
At characteristic voltage U3: ethanol ions, isobutylene ions, benzene ions were completely trapped, and other ions were partially trapped.
At characteristic voltage U4: all 4 ions were completely trapped.
In the process of qualitative and quantitative analysis of gas components of a specific gas mixture, when a single-component gas is measured, under the condition of stable gas flow, the current of the collecting electrode 510 increases along with the increase of voltage, when the characteristic voltage is reached, the current does not change any more, for example, a collecting current-collecting voltage curve is differentiated, the obtained measurement curve is subjected to differentiation processing, the quantity of the gas components in the gas mixture can be judged according to the fact that dI/dU is 0, the characteristic voltage can also be obtained according to the fact that dI/dU is 0, and the applicant can measure that U1 is more than U2, more than U3, and more than U4 through experiments.
In the process of actually measuring the mixed gas of ethanol, isobutene, benzene and toluene with unknown concentration, the characteristic voltage pre-stored in the photoionization measurement device 100 is compared to qualitatively judge the gas components possibly existing in the mixed gas, for example, when isobutene molecules do not exist in the mixed gas, the characteristic voltage U2 cannot be found in the actually measured spectrogram.
In one embodiment, during the actual measurement process, it is found through qualitative analysis that there is unknown component x in the mixed gas besides ethanol, isobutylene, benzene and toluene, and its characteristic voltage is Ux, U2< Ux < U3, and in this case, in order to accurately measure the benzene concentration, the following measurement mode can be adopted:
three measurement voltages Ux, U3 and U4 were selected, the response currents of the collecting electrodes 510 were measured, Ix, I3 and I4 are the response currents at these three collecting voltages. Wherein:
ix is the response current containing all ethanol, isobutene, unidentified gas component x and part of benzene and toluene.
I3 response current containing all ethanol, isobutene, unidentified gas component x, benzene and part of toluene.
(I3-Ix): the interference of all ethanol, isobutene, and unknown gas component x is subtracted, and the response signals of all benzene and part of toluene are included.
I4 response current containing all ethanol, isobutene, unidentified gas components x, benzene and toluene. (I4-I3): the interference of all ethanol, isobutene, unidentified gas components x and benzene is deducted, and the response current of all toluene is included.
Before the gas to be measured is measured, the voltage controller 700 is adjusted, and the parameters of the photoionization measurement device 100 are calibrated under 3 collection voltages Ux, U3 and U4 by respectively measuring with benzene standard gas and/or toluene standard gas. The following formula (11), formula (12) and formula (13) can be used to calibrate the parameters of the photoionization measurement device 100:
(I3-Ix)＝k3xC6H6CC6H6 (11)
(I3-Ix)＝k3xC7H8CC7H8 (12)
(I4-I3)＝k43C7H8CC7H8 (13)
wherein, CC6H6Is the concentration of benzene in the benzene standard gas, CC7H8The concentration of toluene in toluene standard gas; k is a radical of3xC6H6、k3xC7H8And k43C7H8The response sensitivity of the photoionization measurement device 100 under the present measurement conditions; ix, I3 and I4 are response currents obtained at 3 collected voltages Ux, U3 and U4, respectively, after predetermined standard gas is introduced. In the formula (11), the formula (12) and the formula (13), Ix, I3 and I4 may be the same or different and are obtained by different experiments, the formula (11) is an experiment for introducing benzene standard gas, and the formula (12) and the formula (13) are an experiment for introducing toluene standard gas.
In the formula (11), the formula (12) and the formula (13), CC6H6And CC7H8For known parameters, Ix, I3 and I4 are known numbers measured by introducing standard gas, so that k can be determined by formula (11), formula (12) and formula (13)3xC6H6、k3xC7H8And k43C7H8Is used for the solution of the following formula (14) and formula (15).
After the parameters of the photoionization measurement device 100 are calibrated by using the formula (11), the formula (12) and the formula (13), the voltage controller 700 is adjusted, and the gas to be measured is measured at 3 collection voltages Ux, U3 and U4, at this time, the following formula (14) and formula (15) can be used to solve the simultaneous equations to calculate the concentrations of benzene and toluene of the gas to be measured respectively:
(I3-Ix)＝k3xC6H6CC6H6+k3xC7H8CC7H8 (14)
(I4-I3)＝0+k43C7H8CC7H8 (15)
wherein k is3xC6H6、k3xC7H8And k43C7H8For the response sensitivity of the photoionization measurement device 100 under the present measurement conditions, for the known parameters, C, which are calibrated using equation (11), equation (12), and equation (13)C6H6And CC7H8The concentrations of benzene and toluene in the gas to be measured are shown; ix, I3 and I4 are response currents obtained at 3 collecting voltages Ux, U3 and U4 respectively after the gas to be detected is introduced.
In the present example, the response sensitivity in step S110 refers to k in formula (14) and formula (15)3xC6H6、k3xC7H8And k43C7H8. The response current in step S120 refers to Ix, I3, and I4 in formula (14) and formula (15). The component concentration information of the gas to be measured in step S230 refers to C in formula (14) and formula (15)C6H6And CC7H8。
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims (10)

1. A photoionization measurement device, comprising:
a light emitting assembly for emitting light;
the ionization chamber is provided with an ionization cavity for containing gas to be detected, and the ionization chamber is configured to enable light rays emitted by the light emitting component to be emitted into the ionization cavity so as to ionize the gas to be detected in the ionization cavity;
the measuring chamber is provided with an outlet hole passage penetrating through the measuring chamber, and the outlet hole passage is communicated with the ionization cavity so as to enable the ionized gas to be measured to flow out; and
and the detection assembly comprises a collecting electrode and a bias electrode which are electrically connected and is used for detecting the gas to be detected after ionization in the outlet pore passage.
2. The photoionization measurement device of claim 1 wherein the biasing electrode is of unitary construction and the collecting electrode is of unitary construction or the collecting electrode includes a plurality of collecting electrode blocks spaced apart with a first spacer disposed between adjacent collecting electrode blocks.
3. The photoionization measurement device of claim 1, further comprising:
the voltage controller is electrically connected with the detection assembly and is used for controlling the voltage of the detection assembly; and
and the flow controller is arranged on the outlet pore passage and used for controlling the flow of the gas to be detected.
4. The photoionization measurement device of any one of claims 1 to 3 wherein the outlet port is a transversely disposed straight port, the axis of the outlet port being oriented to intersect the direction of light emitted from the light emitting element; the collecting electrode and the bias electrode are arranged on the inner wall of the outlet pore passage and are oppositely arranged.
5. The photoionization measurement device of any one of claims 1 to 3 wherein the outlet port is a vertically disposed straight port, the outlet port having an axis aligned in the same direction as the direction of light emitted from the light emitting element;
the measuring chamber and the light-emitting component are respectively positioned at two sides of the ionization chamber;
the collecting electrode is arranged on the inner wall of the outlet pore passage;
the bias electrode is arranged on the inner wall of the ionization cavity;
the bias electrode is provided with at least one first opening for communicating the outlet channel with the ionization chamber.
6. A method of photoionization measurement, comprising:
acquiring the response sensitivity of the collecting electric block to different components in the gas to be detected;
acquiring the response current of the collecting electric block;
and calculating to obtain the component concentration information of the gas to be detected according to the response sensitivity of the collecting electric block to different components in the gas to be detected and the response current of the collecting electric block.
7. The photoionization measurement method of claim 6 wherein, when there is one collecting electrode, the response sensitivities of the collecting electrode to different components in the gas to be measured at different collecting voltages are obtained; respectively obtaining response currents of the collecting electric blocks under different collecting voltages, and calculating to obtain component concentration information of the gas to be detected according to response sensitivities of the collecting electric blocks to different components in the gas to be detected under different collecting voltages and response currents of the collecting electric blocks under different collecting voltages.
8. The photoionization measurement method of claim 6 wherein, when there is one collecting electrode, the response sensitivities of the collecting electrode to different components in the gas to be measured are obtained for different flow rates of the gas to be measured; respectively acquiring response current of the collecting electric block aiming at different flows of the gas to be detected, and calculating to obtain component concentration information of the gas to be detected according to response sensitivity of the collecting electric block aiming at different flows of the gas to be detected on different components in the gas to be detected and response current of the collecting electric block aiming at different flows of the gas to be detected.
9. The photoionization measurement method of claim 6 wherein, when there are a plurality of the collecting electrode blocks, the response sensitivity of each collecting electrode block to different components in the gas to be measured is obtained; and respectively acquiring the response current of each collecting electric block, and calculating to obtain the component concentration information of the gas to be detected according to the response sensitivity of each collecting electric block to different components in the gas to be detected and the response current of each collecting electric block.
10. The photoionization measurement method of any one of claims 6 to 9, further comprising:
acquiring a response correction coefficient of each collecting electric block to humidity;
and calculating to obtain the component concentration information of the gas to be detected according to the response correction coefficient of each collecting electric block to humidity, the response sensitivity of the collecting electric block to different components in the gas to be detected and the response current of the collecting electric block.
CN202110640121.2A 2021-06-08 2021-06-08 Photoionization measurement device and method Pending CN113189258A (en)

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