CN114113293B - Photo-ionization detector active sensitivity compensation method, detector and detector - Google Patents
Photo-ionization detector active sensitivity compensation method, detector and detector Download PDFInfo
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- CN114113293B CN114113293B CN202111261666.9A CN202111261666A CN114113293B CN 114113293 B CN114113293 B CN 114113293B CN 202111261666 A CN202111261666 A CN 202111261666A CN 114113293 B CN114113293 B CN 114113293B
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
- G01N27/68—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode using electric discharge to ionise a gas
- G01N27/70—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode using electric discharge to ionise a gas and measuring current or voltage
Abstract
The invention provides an active sensitivity compensation method of a photoionization detector, the detector and the detector, wherein the method comprises the following steps: monitoring the temperature and the humidity of the photoionization reference air chamber in real time, and judging whether the temperature and the humidity conditions of the gas detection are met; if yes, acquiring a current value IR of the response of the reference collecting electrode p0 The method comprises the steps of carrying out a first treatment on the surface of the Judging the current value IR p0 If the current is within the set current range, acquiring a current value IM responded by the main collecting electrode, and comparing the current value IM with the current value IR p0 As the response current of the gas to be measured; otherwise, the photoionization detector is subjected to active sensitivity compensation by dynamically adjusting the low-voltage maintaining voltage or the high-voltage lighting voltage of the photoionization detector, and whether the active sensitivity compensation is effective is judged. The invention dynamically adjusts the high-voltage lighting voltage and the low-voltage maintaining voltage to achieve the purpose of active sensitivity compensation, and reduces the influence of device aging and the like on the photoionization gas detection system.
Description
Technical Field
The invention relates to the technical field of photoionization detectors, in particular to an active sensitivity compensation method of a photoionization detector, the detector and the detector.
Background
The photoionization detection technology is used as an accurate and effective VOCs detection means and is increasingly widely applied. The basic principle of the PID (Photo Ionization Detector) photoionization detector is as follows: and when gas molecules with ionization potential less than or equal to ultraviolet energy absorb one photon, ionization occurs to generate positively charged ions and electrons by utilizing ultraviolet rays generated by the inert gas vacuum discharge phenomenon. In the ionization chamber, ions and electrons rapidly move to the metal electrode under the action of an externally applied electric field, a weak current signal is generated between the two electrodes, and the concentration of an organic substance is obtained by detecting the current signal after amplifying the current signal through a weak signal amplifying circuit.
The photoionization detection technology has the characteristics of safety, instantaneity and the like, but when the gas to be detected contains water vapor or the external environment temperature changes, the sensitivity of the photoionization detector is affected; in addition, the PID lamp has a certain service life, and under the condition of keeping the lighting voltage of the PID lamp at a certain level, the sensitivity of the PID lamp is also attenuated along with the lengthening of the running time of the photoionization detector, so that the sensitivity and the detection precision of the photoionization detector are further affected.
Aiming at the problem that the sensitivity of the photoionization detector is gradually attenuated along with time, the method adopted on the market generally carries out concentration curve calibration between response current of the photoionization detector and standard gas in a laboratory at present, and belongs to passive compensation. Because the sensitivity of the photoionization detector is a gradual attenuation process, a plurality of concentration calibration curves of the whole life cycle of the photoionization detector are needed to be made so as to perform sensitivity compensation well, the concentration calibration curves take a long time and have high labor cost, a large memory processor is needed, and when the external environment and the environment during calibration are slightly changed, the pre-stored concentration curves cannot perform sensitivity compensation accurately.
In order to solve the above problems, an ideal technical solution is always sought.
Disclosure of Invention
The invention aims at overcoming the defects of the prior art, and provides an active sensitivity compensation method of a photoionization detector, the detector and the detector.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
the first aspect of the present invention provides a method for compensating active sensitivity of a photoionization detector, the method comprising the steps of:
Monitoring the temperature and the humidity of the photoionization reference air chamber in real time, and judging whether the temperature and the humidity conditions of the gas detection are met;
if yes, acquiring a current value IR of the response of the reference collecting electrode p0 ；
The current value IR p0 Comparing with the set current range, and judging the current value IR p0 Whether within a set current range;
if yes, acquiring a current value IM responded by the main collecting electrode, and comparing the current value IM with the current value IR p0 As the response current of the gas to be measured;
otherwise, dynamically adjusting the low-voltage maintenance voltage or the high-voltage lighting voltage of the photoionization detector to perform active sensitivity compensation on the photoionization detector, and judging whether the active sensitivity compensation is effective;
if the active sensitivity compensation is effective, acquiring a current value IM of the response of the main collecting electrode, and combining the current value IM with a current value IR 'of the response of the reference collecting electrode after the active sensitivity compensation' p0 As the response current of the gas to be measured.
The second aspect of the invention provides an active sensitivity compensation photoionization detector, which comprises a photoionization main channel air chamber, a photoionization reference air chamber, a main channel collecting electrode plate, a reference collecting electrode plate, a polarized electrode plate and a microcontroller, wherein the main channel collecting electrode plate is positioned in the photoionization main channel air chamber, and the reference collecting electrode plate is positioned in the photoionization reference air chamber;
The microcontroller is respectively connected with the main collecting electrode plate, the reference collecting electrode plate and the polarized electrode plate to obtain a current value IR of the main collecting electrode response p0 And a current value IM to which the reference collection electrode is responsive;
the microcontroller also performs the steps of the photoionization detector active sensitivity compensation method described above.
The invention provides an active sensitivity compensation photoionization detector which comprises a main controller, an air filter, an air channel on-off control component, a VOC (volatile organic compound) filtering tank, an air channel switching control component I, an air channel connecting piece I, a photoionization detector, an air channel connecting piece II and a sampling pump, wherein the photoionization detector comprises a photoionization main air channel air chamber and a photoionization reference air chamber;
the air inlet of the air filter is used as a sample inlet;
an air outlet of the air filter is communicated with an air inlet of the air path on-off control assembly in a sealing way, an air outlet of the air path on-off control assembly is communicated with a first air inlet of the air path connecting piece I in a sealing way, and an air outlet of the air path connecting piece I is communicated with an air inlet of the photoionization main air chamber in a sealing way so as to convey air containing gas to be detected into the photoionization main air chamber of the photoionization detector;
The other air outlet of the air filter is communicated with the air inlet of the VOC filtering tank in a sealing way; the air outlet of the VOC filtering tank is communicated with the first air inlet of the air channel switching control assembly I in a sealing way, the first air outlet of the air channel switching control assembly I is communicated with the second air inlet of the air channel connecting piece I in a sealing way, and the second air outlet of the air channel switching control assembly I is communicated with the air inlet of the photoionization reference air chamber in a sealing way so as to convey air which does not contain the gas to be detected into the photoionization reference air chamber of the photoionization detector;
the air outlet of the photoionization main gas chamber is communicated with the first air inlet of the gas circuit connecting piece II in a sealing way, the air outlet of the photoionization reference gas chamber is communicated with the second air inlet of the gas circuit connecting piece II in a sealing way, the air outlet of the gas circuit connecting piece II is communicated with the air inlet of the sampling pump in a sealing way, and the air outlet of the sampling pump is used as a sample outlet;
the main controller is respectively connected with the gas path on-off control assembly, the gas path switching control assembly I and the photoionization detector, and executes the steps of the method for compensating the active sensitivity of the photoionization detector.
A fourth aspect of the present invention provides a method for compensating for active sensitivity of a photo-ionization detector, comprising the steps of:
each photoionization detection period comprises a calibration time period and a detection time period;
entering a calibration time period, and acquiring a current value I of the response of the collecting electrode in the calibration time period p0 The current value I p0 Comparing with the set current range, and judging the current value I p0 Whether within a set current range;
if yes, entering a detection time period, acquiring a current value IC of a collector response in the detection time period, and comparing the current value IC with the current value I p0 As the response current of the gas to be measured;
otherwise, dynamically adjusting the low-voltage maintenance voltage or the high-voltage lighting voltage of the photoionization detector to perform active sensitivity compensation on the photoionization detector, and judging whether the active sensitivity compensation is effective;
if the active sensitivity compensation is effective, entering a detection time period, acquiring a current value IC of the response of a collecting electrode in the detection time period, and combining the current value IC with a current value I 'of the response of the collecting electrode after the active sensitivity compensation' p0 As the response current of the gas to be measured.
A fifth aspect of the present invention provides a computer-readable storage medium having stored thereon a photo-ionization detector active sensitivity compensation program which, when executed by the processor, implements the steps of the photo-ionization detector active sensitivity compensation method (double-gas cell) described above.
A sixth aspect of the present invention provides another computer-readable storage medium having stored thereon a photo-ionization detector active sensitivity compensation program which, when executed by the processor, implements the steps of the photo-ionization detector active sensitivity compensation method (single cell) described above.
Compared with the prior art, the invention has outstanding substantive characteristics and remarkable progress, and concretely comprises the following steps:
1) The invention provides an active sensitivity compensation method for a double-air-chamber photoionization detector, which is different from a passive sensitivity compensation method, and dynamically adjusts high-voltage lighting voltage or low-voltage maintaining voltage according to a current value of a reference collecting electrode obtained in real time in the gas concentration detection process, so that the current value of the reference collecting electrode is between a set PID detection current upper limit and a PID detection current lower limit, the purpose of active sensitivity compensation is achieved, and the influence of factors such as device aging on the photoionization gas detection sensitivity is reduced;
2) The invention also provides a single-lamp-three-electrode structured photoionization detector, which is provided with a photoionization main gas-way chamber and a photoionization reference gas chamber, wherein only sample gas passing through an air filter enters the photoionization main gas-way chamber, and sample gas sequentially passing through the air filter and a VOC filtration tank enters the photoionization reference gas chamber;
when the concentration of the gas to be detected is detected, the main collecting electrode plate in the photoionization main gas chamber and the reference collecting electrode plate in the photoionization reference gas chamber are provided with currents; the current value responded by the main collecting electrode is differed from the current value responded by the reference collecting electrode, so that the influence of water vapor on the detection sensitivity of the photoionization gas is eliminated;
3) The invention provides an active sensitivity compensation method of a photoionization detector for a single air chamber, which is characterized in that air which does not contain gas to be detected enters an ionization chamber in a calibration time period in a time-sharing multiplexing mode, and a high-voltage lighting voltage or a low-voltage maintaining voltage is dynamically adjusted according to a current value of a collecting electrode obtained in real time in the calibration time period, so that the current value responded by a collecting electrode in the calibration time period is between a set PID detection current upper limit and a PID detection current lower limit, and the purpose of active sensitivity compensation is achieved;
In addition, the influence of water vapor on the detection sensitivity of the photoionization gas is eliminated by making a difference between the current value of the collector response in the detection time period and the current value of the collector response in the calibration time period;
4) The invention also carries out constant temperature treatment on the photoionization main gas chamber and the photoionization reference gas chamber, and is generally higher than the external environment, so that the collection flow of the sampling pump is not fluctuated due to temperature change; eliminating the calibration curve between concentration and temperature from the detector; the content of water vapor contained in the gas to be detected entering the ionization chamber is further reduced in a heating mode, so that the device can work in a more severe temperature and humidity environment, the product development period is shortened, and the labor cost and the material cost are reduced.
Drawings
FIG. 1 is a flow chart of the method of active sensitivity compensation of the photo-ionization detector of example 1;
FIG. 2 is a flow chart of dynamically adjusting the low-voltage sustain voltage or the high-voltage ignition voltage of the photoionization detector of the present invention;
FIG. 3 is a flow chart of the photo-ionization detector active sensitivity compensation method (single-air cell time-division multiplexing) in example 4;
FIG. 4 is a schematic diagram of the structure of an active sensitivity compensating photoionization detector (dual plenum) of the present invention;
FIG. 5 is a schematic structural view of the photo-ionization detector (dual gas cell) of the present invention;
FIG. 6 (a) is a schematic structural view of a collecting electrode plate of a photo-ionization detector (double gas cell);
FIG. 6 (b) is a schematic structural view of a polarized electrode sheet of a photoionization detector (dual plenum);
FIG. 6 (c) is a schematic structural view of the electrode base plate of the photo-ionization detector (double gas cell);
FIG. 7 is a schematic diagram of the structure of an active sensitivity compensating photoionization detector (single plenum);
in the figure: 1. an air filter; 2. the gas circuit on-off control assembly; a voc filtration canister; 4. the gas circuit switching control assembly I; 5. the gas path connecting piece I; 6. a photoionization detector; 61. photoionization main gas chamber; 62. a photoionization reference gas cell; 63. collecting electrode plates by a main way; 64. a reference collecting electrode plate; 65. polarizing the electrode plate; 66. an electrode base plate; pid lamp; 68. a main air chamber air inlet; 69. a reference air chamber inlet; 7. the gas path connecting piece II; 8. a sampling pump; 9. shan Qishi photoionization detector; 10. the gas circuit switching control assembly II; 11. a heating block; 12. and a heat preservation box.
Detailed Description
The technical scheme of the invention is further described in detail through the following specific embodiments.
Example 1
Fig. 1 shows a flow chart of a method of photo-ionization detector active sensitivity compensation, comprising the steps of:
monitoring the temperature and the humidity of the photoionization reference air chamber in real time, and judging whether the temperature and the humidity conditions of the gas detection are met;
if yes, acquiring a current value IR of the response of the reference collecting electrode p0 ；
The current value IR p0 Comparing with the set current range, and judging the current value IR p0 Whether within a set current range;
if the current value IR p0 Within the set current range, acquiring a current value IM responded by the main collecting electrode, and combining the current value IM with the current value IMCurrent value IR p0 As the response current of the gas to be measured;
otherwise, dynamically adjusting the low-voltage maintenance voltage or the high-voltage lighting voltage of the photoionization detector to perform active sensitivity compensation on the photoionization detector, and judging whether the active sensitivity compensation is effective;
if the active sensitivity compensation is effective, acquiring a current value IM of the response of the main collecting electrode, and combining the current value IM with a current value IR 'of the response of the reference collecting electrode after the active sensitivity compensation' p0 As the response current of the gas to be measured.
It will be appreciated that if the current value IR of the collector electrode response is referenced p0 At the set PID detection current upper limit I pu And PID detection current lower limit I pd In between, it is described that the photo-ionization detector does not need to be actively compensated for sensitivity, and at this time, the high-voltage lighting voltage V is ensured I0 And a low voltage maintenance voltage V k0 Is unchanged.
If the current value of the reference collector electrode response after the active sensitivity compensation is set to the PID detection current upper limit I pu And PID detection current lower limit I pd If yes, judging that the active sensitivity compensation is effective; otherwise, the active sensitivity compensation is determined to be ineffective.
Specifically, PID detects the upper limit I of the current pu And PID detection current lower limit I pd Belongs to an empirical value and is set before delivery.
As shown in fig. 2, when the photoionization detector performs active sensitivity compensation by dynamically adjusting the low-voltage maintenance voltage or the high-voltage lighting voltage of the photoionization detector and judging whether the active sensitivity compensation is effective, the following steps are executed:
setting the first step as S1, the second step as S2 and the third step as S3;
if the current value IR of the collector electrode response is referred to p0 > set PID detection current upper limit I pu Then:
gradually adjusting the current low-voltage maintaining voltage of the PID lamp by the set first step S1, and gradually reducing the current low-voltage maintaining voltage of the current PID lamp; adjusted low voltage maintenance voltage = current low voltage maintenance voltage-number of steps n1×first step S1;
if the regulated low-voltage maintaining voltage is greater than or equal to the low-voltage maintaining voltage lower limit value V kd And the current value IR 'of the reference collecting electrode response is acquired again' p0 At the set PID detection current upper limit I pu And PID detection current lower limit I pd If yes, judging that the active sensitivity compensation is effective;
if the current low-voltage maintaining voltage of the PID lamp is regulated to be smaller than the lower limit value V of the low-voltage maintaining voltage kd Thereafter, the acquired current value IR 'of the reference collector electrode response' p0 Is also greater than the set PID detection current upper limit I pu Judging that the active sensitivity compensation is invalid, and prompting equipment failure;
if the set PID basic detection current I p < Current value IR of reference collector electrode response p0 < set PID detection current lower limit I pd Then:
gradually adjusting the current low-voltage maintaining voltage of the PID lamp by the set second step S2, wherein the adjusted low-voltage maintaining voltage=the current low-voltage maintaining voltage+the step number N2 is multiplied by the second step S2;
if the regulated low-voltage maintenance voltage is less than or equal to the set low-voltage maintenance voltage upper limit value V ku And the current value IR 'of the reference collecting electrode response is acquired again' p0 At the set PID detection current upper limit I pu And PID detection current lower limit I pd If yes, judging that the active sensitivity compensation is effective;
if the current low-voltage maintaining voltage of the PID lamp is regulated to be larger than the set upper limit value V of the low-voltage maintaining voltage ku Thereafter, the acquired current value IR 'of the reference collector electrode response' p0 Is also smaller than the set PID detection current lower limit I pd Judging that the active sensitivity compensation is invalid, and prompting to clean the PID lamp;
if the current value IR of the collector electrode response is referred to p0 Set PID basic detection current I less than or equal to p Then:
gradually adjusting the current high-voltage lighting voltage of the PID lamp by the set third step S3, wherein the adjusted high-voltage lighting voltage=the current high-voltage lighting voltage+the step number N3 is multiplied by the third step S3;
if the regulated high-voltage lighting voltage is less than or equal to the high-voltage lighting voltage upper limit value V lu And the current value IR 'of the reference collecting electrode response is acquired again' p0 At the set PID detection current upper limit I pu And PID detection current lower limit I pd If yes, judging that the active sensitivity compensation is effective;
if the high-voltage lighting voltage of the PID lamp is adjusted to be greater than the set high-voltage lighting voltage upper limit value V lu Thereafter, the acquired current value IR 'of the reference collector electrode response' p0 The PID basic detection current I is smaller than or equal to the set value p And judging that the active sensitivity compensation is invalid, and prompting that the PID lamp is bad.
It will be appreciated that equipment failure may be caused by other part of the PID lamp failure, such as abnormal power supply, etc.; PID lamps have been broken to indicate long life of the photoionization detector, and failure caused by device aging.
In the process of gradually adjusting the current low-voltage maintaining voltage of the PID lamp by the set first step S1, after each adjustment, it is determined whether the adjusted low-voltage maintaining voltage is equal to or higher than the low-voltage maintaining voltage lower limit V kd If yes, loading the regulated low-voltage maintaining voltage of the PID lamp, and acquiring the current value IR 'of the response of the reference collecting electrode again' p0, And judges the current value IR' p0 If the current value is within the set current range, acquiring a current value IM of the response of the main collecting electrode, and compensating the current value IM with a current value IR 'of the response of the reference collecting electrode after the active sensitivity' p0 As the response current of the gas to be measured; if the current value IR' p0 If the current is not in the set current range, performing the next step adjustment by using the set first step S1; up to the current value IR 'of the reference collecting electrode response after active sensitivity compensation' p0 At the set PID detection current upper limit I pu And PID detection current lower limit I pd Between, or the low-voltage maintenance voltage is not already at the low-voltage maintenance voltage lower limit value V kd With low pressure maintenanceVoltage upper limit V ku Between them.
The process of gradually adjusting the current low-voltage sustain voltage of the PID lamp in the set second step S2 and the process of gradually adjusting the current high-voltage ignition voltage of the PID lamp in the set third step S3 are not described in detail herein.
Specifically, in order to achieve both the efficiency and accuracy of the active sensitivity compensation, the third step S3 is generally larger than the first step S1 and the second step S2; the first step S1 and the second step S2 may be equal or unequal, or may be adjusted in real time.
It can be understood that, in the process of dynamically adjusting the high-voltage lighting voltage, if the adjusted high-voltage lighting voltage is less than or equal to the high-voltage lighting voltage upper limit value V lu Then the regulated high-voltage lighting voltage is loaded, and after the lighting operation is performed again, the current value IR 'responded by the reference collecting electrode is obtained again' p0 And judges the current value IR' p0 Whether within a set current range.
The lighting voltage and the holding voltage of the PID lamp directly influence the current generated by ionizing the gas to be detected, namely influence the sensitivity and the detection precision of the PID detector; therefore, when the photoionization detector needs active sensitivity compensation, the PID detector keeps the zero point constant by dynamically adjusting the lighting voltage and the holding voltage of the PID lamp in real time, so as to further ensure the sensitivity of the PID lamp.
The invention refers to the current value IR of the collecting electrode p0 The matching result with the set current range is the trigger condition, if the current value IR p0 Matching with the set current range, active sensitivity compensation is not needed, and the current value IR is subtracted from the current value IM of the main collecting electrode response p0 Obtaining the response current of the gas to be tested; if the current value IR p0 If the current range is not matched with the set current range, active sensitivity compensation is carried out by adjusting high-voltage lighting voltage or low-voltage maintaining voltage, so that the invention does not need to rely on a plurality of concentration calibration curves calibrated in advance; active sensitivity compensation can be performed in situ, in real time, dynamically and accurately even if the external environment or the environment at the time of calibration is slightly changedThe detection precision and the service life of the pumping type photoionization detector can be greatly improved.
Example 2
As shown in fig. 5 and fig. 6 (a) to 6 (c), the present embodiment shows a specific implementation of an active sensitivity compensation photoionization detector:
the photoionization detector comprises a PID lamp 67, a photoionization main gas chamber 61, a photoionization reference gas chamber 62, a main collecting electrode plate 63, a reference collecting electrode plate 64, a polarized electrode plate 65 and a microcontroller, wherein the main collecting electrode plate 63 is positioned in the photoionization main gas chamber 61, the reference collecting electrode plate 64 is positioned in the photoionization reference gas chamber 62, one part of the polarized electrode plate 65 is positioned in the photoionization main gas chamber 61, and the other part of the polarized electrode plate 65 is positioned in the photoionization reference gas chamber 62;
The microcontroller is respectively connected with the main collecting electrode plate 63, the reference collecting electrode plate 64 and the polarized electrode plate 65 to obtain a current value IR of the main collecting electrode response p0 And a current value IM to which the reference collection electrode is responsive;
the microcontroller also performs the steps of the photoionization detector active sensitivity compensation method of embodiment 1.
It will be appreciated that the photoionization detector of the single lamp-three electrode structure is provided with a photoionization main gas-way chamber 61 and a photoionization reference gas chamber 62, and the two gas chambers can share a PID lamp 67, and ultraviolet rays emitted by the PID lamp 67 can irradiate into the photoionization main gas-way chamber 61 and the photoionization reference gas chamber 62; the two air chambers can be respectively provided with a PID lamp, and at the moment, the voltage adjustment of the PID lamps in the two air chambers is kept consistent.
A partition plate is arranged between the photo-ionization main gas-passing chamber 61 and the photo-ionization reference gas-passing chamber 62 of the photo-ionization detector 6, so that gas between the photo-ionization main gas-passing chamber 61 and the photo-ionization reference gas-passing chamber 62 is not communicated; one side of the photo-ionization main gas chamber 61 is provided with a main gas chamber air inlet 68, and the other side is provided with a main gas chamber air outlet; a reference air chamber air inlet 69 is provided on one side of the photo-ionised reference air chamber 62 and a reference air chamber air outlet is provided on the other side.
Only the sample gas passing through the air filter 1 enters the photo-ionization main gas chamber 61, and the sample gas passing through the air filter 1 and the VOC filtering tank 3 in sequence enters the photo-ionization reference gas chamber 62; when the concentration of the gas to be detected is detected, the main collecting electrode plate 63 in the photoionization main gas chamber 61 and the reference collecting electrode plate 64 in the photoionization reference gas chamber 62 are provided with currents; and (3) making a difference between the current value responded by the main collecting electrode and the current value responded by the reference collecting electrode, so that the influence of water vapor on the detection sensitivity of the photoionization gas is eliminated.
It can be understood that when the gas to be measured is contained in the region to be measured, the current value of the main path collecting electrode response of the photoionization detector is greater than the current value of the reference collecting electrode response; when the region to be measured does not contain the gas to be measured or the concentration of the gas to be measured is extremely low, the current value of the main-path collecting electrode response of the photoionization detector=the current value of the reference collecting electrode response.
Specifically, when the electrode plate is installed, the collecting electrode plate is arranged on the polarized electrode plate; the pins on two sides of the main collecting electrode plate 63 are bent and then welded to the connection part of the main collecting electrode on the electrode bottom plate 66, and the pins on two sides of the reference collecting electrode plate 64 are bent and then welded to the connection part of the reference collecting electrode on the electrode bottom plate 66; the polarized electrode plates 65 are shared, and four pins of the polarized electrode plates 65 are bent and welded to the polarized electrode connection parts on the electrode bottom plate 66; so that the improved active sensitivity compensation photoionization detector is in a single lamp-three electrode structure.
Further, the photoionization detector 6 is further provided with a heating block 11, and the heating block 11 is fixed outside the shell of the photoionization detector 6 through a thermal insulation box 12, so that the photoionization main gas chamber and the photoionization reference gas chamber are at constant temperature (generally higher than the external environment); a temperature and humidity sensor is further disposed in the photoionization reference air chamber 62, and the temperature and humidity sensor and the heating block 11 are connected with the microcontroller so as to monitor the temperature and humidity conditions in the ionization chamber in real time. The microcontroller judges whether the photoionization reference air chamber 62 meets the set gas detection conditions or not through the temperature and humidity sensor, and when the set gas detection conditions are not met, the water vapor content in the gas to be detected entering the ionization chamber is further reduced through a heating mode, so that the device can work in a more severe temperature and humidity environment, the product development period is shortened, and the labor cost and the material cost are reduced; therefore, the detector is free from carrying out a calibration curve between concentration and temperature, and the influence of water vapor on the sensitivity and detection precision of the photoionization detector can be further eliminated.
Example 3
As shown in fig. 4, the embodiment provides an active sensitivity compensation photoionization detector, which comprises a main controller, an air filter 1, an air channel on-off control component 2, a VOC filtering tank 3, an air channel switching control component i 4, an air channel connecting piece i 5, a photoionization detector 6, an air channel connecting piece ii 7 and a sampling pump 8, wherein the photoionization detector 6 comprises a photoionization main air channel air chamber 61 and a photoionization reference air chamber 62;
The air inlet of the air filter 1 is used as a sample inlet;
an air outlet of the air filter 1 is in sealed communication with an air inlet of the air path on-off control assembly 2, an air outlet of the air path on-off control assembly 2 is in sealed communication with a first air inlet of the air path connecting piece I5, and an air outlet of the air path connecting piece I5 is in sealed communication with an air inlet of the photoionization main air path chamber 61 so as to convey air containing gas to be detected into the photoionization main air path chamber 61 of the photoionization detector 6;
the other air outlet of the air filter 1 is communicated with the air inlet of the VOC filtering tank 3 in a sealing way; the air outlet of the VOC filtering tank 3 is communicated with the first air inlet of the air channel switching control assembly I4 in a sealing way, the first air outlet of the air channel switching control assembly I4 is communicated with the second air inlet of the air channel connecting piece I5 in a sealing way, and the second air outlet of the air channel switching control assembly I4 is communicated with the air inlet of the photoionization reference air chamber 62 in a sealing way so as to convey air which does not contain the gas to be detected into the photoionization reference air chamber 62 of the photoionization detector 6;
the air outlet of the photoionization main air chamber 61 is communicated with the first air inlet of the air channel connecting piece II 7 in a sealing way, the air outlet of the photoionization reference air chamber 62 is communicated with the second air inlet of the air channel connecting piece II 7 in a sealing way, the air outlet of the air channel connecting piece II 7 is communicated with the air inlet of the sampling pump 8 in a sealing way, and the air outlet of the sampling pump 8 is used as a sample outlet;
The main controller is respectively connected with the gas path on-off control assembly 2, the gas path switching control assembly I4 and the photoionization detector 6, and executes the steps of the photoionization detector active sensitivity compensation method in the embodiment 1.
The air filter 1 mainly performs a pretreatment function on sample gas, namely, filters particle dust, macromolecular water drops and partial water vapor in ambient air and gas to be detected, so as to prevent small particles or water vapor from entering an air chamber of the photoionization detector and affecting the detection precision and sensitivity of a photoionization detection system; the VOC filtering tank 3 filters Volatile Organic Compounds (VOC) of the gas to be detected or the ambient air entering the air chamber, so as to obtain clean air for cleaning the air chamber of the photoionization detector. The gas circuit on-off control assembly 2, the gas circuit switching control assembly I4, the gas circuit connecting piece I5, the gas circuit connecting piece II 7 and the sampling pump 8 are used for realizing dynamic switching of gas circuit detection and cleaning functions.
It can be understood that the main controller changes the output voltage of the booster circuit by controlling the DAC, thereby changing the lighting voltage and the sustain voltage.
Specifically, the gas circuit on-off control assembly 2 is an electromagnetic two-way valve, the gas circuit switching control assembly I4 is an electromagnetic three-way valve, and the gas circuit connecting piece I5 and the gas circuit connecting piece II 7 are three-way quick connectors.
As shown in fig. 5 and fig. 6 (a) to 6 (c), the photoionization detector 6 further includes an electrode base plate 66, and a main collecting electrode plate 63, a reference collecting electrode plate 64 and a polarized electrode plate 65 which are positioned on the electrode base plate 66, wherein the main collecting electrode plate 63 is positioned in the photoionization main gas chamber 61, and the reference collecting electrode plate 64 is positioned in the photoionization reference gas chamber 62; a portion of the polarized electrode sheet 65 is located within the photo-ionization main plenum 61 and another portion of the polarized electrode sheet 65 is located within the photo-ionization reference plenum 62.
Specifically, a heating block is also arranged outside the sampling pump 8, so that the sampling pump keeps constant temperature, the constant temperature is generally set to 45 degrees, and the air extraction flow of the sampling pump is ensured not to change along with the change of the external environment temperature.
When the current value of the reference collecting electrode deviates from the set interval range along with the lengthening of the running time of the device, the high-voltage lighting voltage and the low-voltage maintaining voltage are changed to reach the upper limit value or the lower limit value, and the current value of the reference collecting electrode cannot be made to be in the specified range, a user or a manufacturer is prompted on a display interface to replace the PID lamp, so that normal gas detection can be performed.
Further, the main controller acquires the current value IR of the response of the reference collecting electrode for the first time p0 At that time, execution:
step 101, powering on and starting up, setting the temperature and humidity working range of the photoionization detector 6, and entering the preheating state of the gas circuit, the sampling pump and the ionization chamber to enable the temperature to be quickly and constantly set;
102, monitoring the temperature and the humidity in the photoionization reference air chamber 62 in real time through a temperature and humidity sensor, and judging whether the temperature and humidity conditions of the gas detection are met;
step 103, setting the upper limit value V of the high-voltage lighting voltage lu Lower limit V of high-voltage lighting voltage ld、 Upper limit V of low voltage maintenance voltage ku And a lower limit value V of the low-voltage maintenance voltage kd ；
Under the condition of meeting the temperature and humidity of gas detection, the PID lamp is turned on according to the set high-voltage lighting voltage, and then the power supply voltage of the PID lamp is adjusted from the high-voltage lighting voltage to the set low-voltage maintaining voltage V k0 ；
Step 104, closing the gas path on-off control assembly 2 and the gas path switching control assembly I4, and opening the sampling pump 8 to enable air which does not contain the gas to be detected to enter the photoionization reference air chamber 62, and cleaning the photoionization reference air chamber 62;
step 105, after cleaning the photoionization reference air chamber 62 for a preset time T1, the main controller reads the current value IR of the reference collecting electrode response through the analog-to-digital conversion module p0 。
In addition to active sensitivity compensation of the photo-ionization detector at power-up, the current value IR at the reference collection electrode is measured throughout the gas detection process p0 The upper limit I of PID detection current is not set pu And PID detection current lower limit I pd In the case of the two, active sensitivity compensation is performed.
Specifically, the gas detection process is as follows:
step 201, closing the air passage on-off control assembly 2, opening the air passage switching control assembly I4, opening the sampling pump 8, and entering a clean state of the photoionization main air passage chamber 61;
step 202, after the photoionization main gas chamber 61 is cleaned for a preset time A, continuously keeping the gas path on-off control assembly 2 closed and the sampling pump 8 opened, closing the gas path switching control assembly I4, and entering a clean state of the photoionization reference gas chamber 62;
step 203, after the photoionization reference air chamber 62 is cleaned for a preset time B, keeping on closing the air path switching control assembly i 4 and opening the sampling pump 8, opening the air path on-off control assembly 2, and entering a photoionization gas detection state:
the gas to be tested enters the photoionization main gas chamber 61 through a sample injection port, an air filter 1, a gas circuit on-off control assembly 2 and a gas circuit connecting piece I5, and also enters the photoionization reference gas chamber 62 through the sample injection port, the air filter 1, a VOC filtration tank 3, a gas circuit switching control assembly I4 and the gas circuit connecting piece I5;
The main controller reads the current value IR responded by the reference collecting electrode through the analog-to-digital conversion module p0 Judging the current value IR p0 Whether within a set current range;
if the current value IR p0 In the set current range, reading the current value IM responded by the main collecting electrode through the analog-to-digital conversion module, and comparing the current value IM with the current value IR p0 As the response current of the gas to be measured;
if the current value IR p0 If the current is not in the set current range, dynamically adjusting the low-voltage maintenance voltage or the high-voltage lighting voltage of the photoionization detector, and performing active sensitivity compensation on the photoionization detector; if the active sensitivity compensation is effective, acquiring a current value IM of the response of the main collecting electrode, and combining the current value IM with a current value IR 'of the response of the reference collecting electrode after the active sensitivity compensation' p0 As the response current of the gas to be measured;
step 204, closing the air passage on-off control assembly 2, opening the air passage switching control assembly I4, keeping the sampling pump 8 in an open state, and entering a clean state of the photo-ionization main air passage chamber 61;
step 205, closing the gas path switching control assembly I, opening the sampling pump, opening the gas path on-off control assembly 2, and entering a photoionization gas detection state;
Thereafter, cycling between a main plenum cleaning state and a detection state occurs.
Example 4
The embodiment provides a specific implementation mode of an active sensitivity compensation method of a photoionization detector for a single-air-chamber photoionization detector;
as shown in fig. 3, the method for compensating the active sensitivity of the photoionization detector for a single gas chamber comprises the following steps:
each photoionization detection period comprises a calibration time period and a detection time period;
entering a calibration time period, and acquiring a current value I of the response of the collecting electrode in the calibration time period p0 The current value I p0 Comparing with the set current range, and judging the current value I p0 Whether within a set current range;
if yes, entering a detection time period, and acquiring current responded by a collecting electrode in the detection time periodA value IC, which is used for comparing the current value IC with the current value I p0 As the response current of the gas to be measured;
otherwise, dynamically adjusting the low-voltage maintenance voltage or the high-voltage lighting voltage of the photoionization detector to perform active sensitivity compensation on the photoionization detector, and judging whether the active sensitivity compensation is effective;
if the active sensitivity compensation is effective, entering a detection time period, acquiring a current value IC of the response of a collecting electrode in the detection time period, and combining the current value IC with a current value I 'of the response of the collecting electrode after the active sensitivity compensation' p0 As the response current of the gas to be measured.
The calibration period of the photoionization detection period is not fixed, and the current value I of the collector response is received in the calibration period p0 Ending the timing of the calibration time period and starting the timing of the detection time period when the set current range is reached, and putting the Shan Qishi photoionization detector 9 into a detection state; when the detection period timer reaches a predetermined time length, the detection state of the Shan Qishi photoionization detector 9 ends, and the single cell photoionization detector 9 enters a calibration state.
In the gas detection process to be detected, the calibration time period and the detection time period are alternately and circularly carried out, and if the active sensitivity compensation is invalid in the calibration time period, the equipment is prompted to be faulty or the PID lamp is damaged, so that the gas concentration detection cannot be carried out.
As shown in fig. 2, when the photoionization detector performs active sensitivity compensation by dynamically adjusting the low-voltage maintenance voltage or the high-voltage lighting voltage of the photoionization detector and judging whether the active sensitivity compensation is effective, the following steps are executed:
setting the first step as S1, the second step as S2 and the third step as S3;
if the current value I of the collector response in the calibration period p0 > set PID detection current upper limit I pu Then:
gradually adjusting the current low-voltage maintaining voltage of the PID lamp by the set first step S1, wherein the adjusted low-voltage maintaining voltage=the current low-voltage maintaining voltage-step number N1 is multiplied by the first step S1;
if the regulated low-voltage maintaining voltage is greater than or equal to the low-voltage maintaining voltage lower limit value V kd And the current value I of the collector response in the calibration period acquired again p0 At the set PID detection current upper limit I pu And PID detection current lower limit I pd If yes, judging that the active sensitivity compensation is effective;
if the current low-voltage maintaining voltage of the PID lamp is regulated to be smaller than the lower limit value V of the low-voltage maintaining voltage kd Thereafter, the current value I 'of the collector response is obtained during the calibration period' p0 Is also greater than the set PID detection current upper limit I pu Judging that the active sensitivity compensation is invalid, and prompting equipment failure;
if the set PID basic detection current I p Current value I of collector response in calibration period p0 < set PID detection current lower limit I pd Then:
gradually adjusting the current low-voltage maintaining voltage of the PID lamp by the set second step S2, wherein the adjusted low-voltage maintaining voltage=the current low-voltage maintaining voltage+the step number N2 is multiplied by the second step S2;
if the regulated low-voltage maintenance voltage is less than or equal to the set low-voltage maintenance voltage upper limit value V ku And the current value I 'of the collector response in the calibration period acquired again' p0 At the set PID detection current upper limit I pu And PID detection current lower limit I pd If yes, judging that the active sensitivity compensation is effective;
if the current low-voltage maintaining voltage of the PID lamp is regulated to be larger than the set upper limit value V of the low-voltage maintaining voltage ku Thereafter, the current value I 'of the collector response is obtained during the calibration period' p0 Is also smaller than the set PID detection current lower limit I pd Judging that the active sensitivity compensation is invalid, and prompting to clean the PID lamp;
if the current value I of the collector response in the calibration period p0 Set PID basic detection current I less than or equal to p Then:
gradually adjusting the current high-voltage lighting voltage of the PID lamp by the set third step S3, wherein the adjusted high-voltage lighting voltage=the current high-voltage lighting voltage+the step number N3 is multiplied by the third step S3;
if the regulated high-voltage lighting voltage is less than or equal to the high-voltage lighting voltage upper limit value V lu And the current value I 'of the collector response in the calibration period acquired again' p0 At the set PID detection current upper limit I pu And PID detection current lower limit I pd If yes, judging that the active sensitivity compensation is effective;
if the high-voltage lighting voltage of the PID lamp is adjusted to be greater than the set high-voltage lighting voltage upper limit value V lu Thereafter, the current value I 'of the collector response is obtained during the calibration period' p0 The PID basic detection current I is smaller than or equal to the set value p And judging that the active sensitivity compensation is invalid, and prompting that the PID lamp is bad.
Specifically, in order to achieve both the efficiency and accuracy of the active sensitivity compensation, the third step S3 is generally larger than the first step S1 and the second step S2; the first step S1 and the second step S2 may be equal or unequal, or may be adjusted in real time.
It can be understood that, in the process of dynamically adjusting the high-voltage lighting voltage, if the adjusted high-voltage lighting voltage is less than or equal to the high-voltage lighting voltage upper limit value V lu The regulated high-voltage lighting voltage is loaded, the lighting operation is carried out again, and the current value I 'of the response of the collecting electrode in the calibration period is obtained again' p0 And judging the current value I' p0 Whether within a set current range.
Specifically, a schematic structural diagram of the active sensitivity compensation photoionization detector (single air chamber) is shown in fig. 7, and the active sensitivity compensation photoionization detector comprises an air filter 1, a VOC filtration tank 3, a single air chamber photoionization detector 9, an air path switching control component II 10, a sampling pump 8 and a microcontroller; the microcontroller is respectively connected with the Shan Qishi photoionization detector 9, the gas circuit switching control assembly II 10 and the sampling pump 8. In the calibration time period, the gas to be detected enters a single-gas-chamber photoionization detector 9 through an air filter 1, a gas circuit switching control assembly II 10 and a VOC filtering tank 3; in the detection time period, the gas to be detected enters the single-gas-chamber photoionization detector 9 through the air filter 1 and the gas path switching control component II 10. Through the mode of time-sharing multiplexing, air which does not contain gas to be detected enters an ionization chamber of the Shan Qishi photoionization detector 9 in a calibration time period, and the high-voltage lighting voltage or the low-voltage maintaining voltage is dynamically adjusted according to the current value of a collecting electrode obtained in real time in the calibration time period, so that the current value of the response of the collecting electrode in the calibration time period is between a set PID detection current upper limit and a PID detection current lower limit, the zero value is kept constant, and the purpose of active sensitivity compensation is achieved.
Specifically, the air path switching control assembly II 10 is an electromagnetic four-way valve.
Further, the Shan Qishi photoionization detector 9 is further provided with a heating block, and the heating block is fixed outside the shell through a heat preservation box; and a temperature and humidity sensor is further arranged in the ionization chamber of the Shan Qishi photoionization detector 9, and the temperature and humidity sensor and the heating block are connected with the microcontroller so as to monitor the temperature and humidity conditions in the ionization chamber in real time and judge whether the temperature and humidity conditions meet the set gas detection conditions. When the set gas detection conditions are not met, the water vapor content in the gas to be detected entering the ionization chamber is further reduced in a heating mode, so that the equipment can work in a more severe temperature and humidity environment, the product development period is shortened, and the labor cost and the material cost are reduced; therefore, the ionization chamber of the Shan Qishi photoionization detector 9 is kept at a constant temperature (generally higher than the external environment) during the detection process, so that the detector is free from performing a calibration curve between concentration and temperature, and the influence of water vapor on the detection sensitivity and detection accuracy of the photoionization detector can be further eliminated.
Example 5
The present embodiment provides a computer-readable storage medium having stored thereon a photo-ionization detector active sensitivity compensation program which, when executed by the processor, implements the steps of the photo-ionization detector active sensitivity compensation method as in embodiment 1.
The present embodiment provides a computer-readable storage medium having stored thereon a photoionization detector active sensitivity compensation program which, when executed by the processor, implements the steps of the photoionization detector active sensitivity compensation method as in embodiment 4.
In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.
Those of ordinary skill in the art will appreciate that the algorithm steps of the examples described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or as a combination of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
The above-described method, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer-readable storage medium. Based on such understanding, the present application may implement all or part of the flow of the method of the above embodiment, or may be implemented by a computer program to instruct related hardware, where the computer program may be stored in a computer readable storage medium, and when the computer program is executed by a processor, the steps of each method embodiment may be implemented. The computer program comprises computer program code, and the computer program code can be in a source code form, an object code form, an executable file or some intermediate form and the like.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same; while the invention has been described in detail with reference to the preferred embodiments, those skilled in the art will appreciate that: modifications may be made to the specific embodiments of the present invention or equivalents may be substituted for part of the technical features thereof; without departing from the spirit of the invention, it is intended to cover the scope of the invention as claimed.
Claims (8)
1. A method for compensating for active sensitivity of a photo-ionization detector, comprising the steps of:
monitoring the temperature and the humidity of the photoionization reference air chamber in real time, and judging whether the temperature and the humidity conditions of the gas detection are met;
if yes, acquiring a current value IR of the response of the reference collecting electrode p0 ；
The current value IR p0 Comparing with the set current range, and judging the current value IR p0 Whether within a set current range;
if yes, acquiring a current value IM responded by the main collecting electrode, and comparing the current value IM with the current value IR p0 As the response current of the gas to be measured;
otherwise, dynamically adjusting the low-voltage maintenance voltage or the high-voltage lighting voltage of the photoionization detector to perform active sensitivity compensation on the photoionization detector, and judging whether the active sensitivity compensation is effective;
If the active sensitivity compensation is effective, acquiring a current value IM of the response of the main collecting electrode, and combining the current value IM with a current value IR 'of the response of the reference collecting electrode after the active sensitivity compensation' p0 As the response current of the gas to be measured;
the method comprises the following steps of performing active sensitivity compensation on the photoionization detector by dynamically adjusting low-voltage maintenance voltage or high-voltage lighting voltage of the photoionization detector, judging whether the active sensitivity compensation is effective or not, and executing the following steps:
setting the first step as S1, the second step as S2 and the third step as S3;
if the current value IR of the collector electrode response is referred to p0 > set PID detection current upper limit I pu Then:
gradually adjusting the current low-voltage maintaining voltage of the PID lamp by the set first step S1, wherein the adjusted low-voltage maintaining voltage=the current low-voltage maintaining voltage-step number N1 is multiplied by the first step S1;
if the regulated low-voltage maintaining voltage is greater than or equal to the low-voltage maintaining voltage lower limit value V kd And the current value IR 'of the reference collecting electrode response is acquired again' p0 At the set PID detection current upper limit I pu And PID detection current lower limit I pd If yes, judging that the active sensitivity compensation is effective;
if the current low-voltage maintaining voltage of the PID lamp is regulated to be smaller than the lower limit value V of the low-voltage maintaining voltage kd Thereafter, the acquired current value IR 'of the reference collector electrode response' p0 Is also greater than the set PID detection current upper limit I pu Judging that the active sensitivity compensation is invalid, and prompting equipment failure;
if the set PID basic detection current I p < Current value IR of reference collector electrode response p0 < set PID detection current lower limit I pd Then:
gradually adjusting the current low-voltage maintaining voltage of the PID lamp by the set second step S2, wherein the adjusted low-voltage maintaining voltage=the current low-voltage maintaining voltage+the step number N2 is multiplied by the second step S2;
if the regulated low-voltage maintenance voltage is less than or equal to the set low-voltage maintenance voltage upper limit value V ku And the current value IR 'of the reference collecting electrode response is acquired again' p0 At the set PID detection current upper limit I pu And PID detection current lower limit I pd If yes, judging that the active sensitivity compensation is effective;
if the current low-voltage maintaining voltage of the PID lamp is regulated to be larger than the set upper limit value V of the low-voltage maintaining voltage ku Thereafter, the acquired current value IR 'of the reference collector electrode response' p0 Is also smaller than the set PID detection current lower limit I pd Judging that the active sensitivity compensation is invalid, and prompting to clean the PID lamp;
if the current value IR of the collector electrode response is referred to p0 Set PID basic detection current I less than or equal to p Then:
gradually adjusting the current high-voltage lighting voltage of the PID lamp by the set third step S3, wherein the adjusted high-voltage lighting voltage=the current high-voltage lighting voltage+the step number N3 is multiplied by the third step S3;
if the regulated high-voltage lighting voltage is less than or equal to the high-voltage lighting voltage upper limit value V lu And the current value IR 'of the reference collecting electrode response is acquired again' p0 At the set PID detection current upper limit I pu And PID detection current lower limit I pd If yes, judging that the active sensitivity compensation is effective;
if the high-voltage lighting voltage of the PID lamp is adjusted to be greater than the set high-voltage lighting voltage upper limit value V lu Thereafter, the acquired current value IR 'of the reference collector electrode response' p0 The PID basic detection current I is smaller than or equal to the set value p And judging that the active sensitivity compensation is invalid, and prompting that the PID lamp is bad.
2. An active sensitivity compensating photoionization detector, characterized by: the photo-ionization device comprises a photo-ionization main gas chamber, a photo-ionization reference gas chamber, a main collecting electrode plate, a reference collecting electrode plate, a polarized electrode plate and a microcontroller, wherein the main collecting electrode plate is positioned in the photo-ionization main gas chamber, and the reference collecting electrode plate is positioned in the photo-ionization reference gas chamber;
the microcontroller is respectively connected with the main collecting electrode plate, the reference collecting electrode plate and the polarized electrode plate to obtain a current value IR of the main collecting electrode response p0 And a current value IM to which the reference collection electrode is responsive;
the microcontroller also performs the steps of the photo-ionization detector active sensitivity compensation method of claim 1.
3. An active sensitivity compensating photoionization detector, characterized by: the system comprises a main controller, an air filter, an air channel on-off control assembly, a VOC filtering tank, an air channel switching control assembly I, an air channel connecting piece I, a photoionization detector, an air channel connecting piece II and a sampling pump, wherein the photoionization detector comprises a photoionization main air channel air chamber and a photoionization reference air chamber;
the air inlet of the air filter is used as a sample inlet;
an air outlet of the air filter is communicated with an air inlet of the air path on-off control assembly in a sealing way, an air outlet of the air path on-off control assembly is communicated with a first air inlet of the air path connecting piece I in a sealing way, and an air outlet of the air path connecting piece I is communicated with an air inlet of the photoionization main air chamber in a sealing way so as to convey air containing gas to be detected into the photoionization main air chamber of the photoionization detector;
the other air outlet of the air filter is communicated with the air inlet of the VOC filtering tank in a sealing way; the air outlet of the VOC filtering tank is communicated with the first air inlet of the air channel switching control assembly I in a sealing way, the first air outlet of the air channel switching control assembly I is communicated with the second air inlet of the air channel connecting piece I in a sealing way, and the second air outlet of the air channel switching control assembly I is communicated with the air inlet of the photoionization reference air chamber in a sealing way so as to convey air which does not contain the gas to be detected into the photoionization reference air chamber of the photoionization detector;
The air outlet of the photoionization main gas chamber is communicated with the first air inlet of the gas circuit connecting piece II in a sealing way, the air outlet of the photoionization reference gas chamber is communicated with the second air inlet of the gas circuit connecting piece II in a sealing way, the air outlet of the gas circuit connecting piece II is communicated with the air inlet of the sampling pump in a sealing way, and the air outlet of the sampling pump is used as a sample outlet;
the main controller is respectively connected with the gas path on-off control assembly, the gas path switching control assembly I and the photoionization detector, and executes the steps of the method for compensating the active sensitivity of the photoionization detector according to claim 1.
4. The active sensitivity compensation photoionization detector of claim 3, wherein the master controller first obtains a current value IR of the reference collection electrode response p0 At that time, execution:
step 101, powering on and starting up, setting the temperature and humidity working range of the photoionization detector, and entering the preheating state of the ionization chamber to enable the temperature to be quickly and constantly set;
102, monitoring the temperature and the humidity in a photoionization reference gas chamber in real time through a temperature and humidity sensor, and judging whether the temperature and the humidity conditions of gas detection are met;
Step 103, setting the upper limit value V of the high-voltage lighting voltage lu Upper limit V of low voltage maintenance voltage ku And a lower limit value V of the low-voltage maintenance voltage kd ；
Under the condition of meeting the temperature and humidity of gas detection, the PID lamp is turned on according to the set high-voltage lighting voltage, and then the power supply voltage of the PID lamp is adjusted from the high-voltage lighting voltage to the set low-voltage maintaining voltage V k0 ；
104, closing the gas path on-off control assembly and the gas path switching control assembly I, and opening the sampling pump to enable air which does not contain the gas to be detected to enter the photoionization reference air chamber, and cleaning the photoionization reference air chamber;
step 105, after cleaning the photoionization reference air chamber for a preset time T1, the main controller reads the current value IR responded by the reference collecting electrode through the analog-to-digital conversion module p0 。
5. The active sensitivity compensating photoionization detector of claim 3, wherein: the photoionization detector further comprises a main collecting electrode plate, a reference collecting electrode plate and a polarized electrode plate, wherein the main collecting electrode plate is positioned in the photoionization main gas chamber, and the reference collecting electrode plate is positioned in the photoionization reference gas chamber.
6. A method for compensating for active sensitivity of a photo-ionization detector, comprising the steps of:
Each photoionization detection period comprises a calibration time period and a detection time period;
entering a calibration time period, and acquiring a current value I of the response of the collecting electrode in the calibration time period p0 The current value I p0 Comparing with the set current range, and judging the currentValue I p0 Whether within a set current range;
if yes, entering a detection time period, acquiring a current value IC of a collector response in the detection time period, and comparing the current value IC with the current value I p0 As the response current of the gas to be measured;
otherwise, dynamically adjusting the low-voltage maintenance voltage or the high-voltage lighting voltage of the photoionization detector to perform active sensitivity compensation on the photoionization detector, and judging whether the active sensitivity compensation is effective;
if the active sensitivity compensation is effective, entering a detection time period, acquiring a current value IC of the response of a collecting electrode in the detection time period, and combining the current value IC with a current value I 'of the response of the collecting electrode after the active sensitivity compensation' p0 As the response current of the gas to be measured;
the method comprises the following steps of performing active sensitivity compensation on the photoionization detector by dynamically adjusting low-voltage maintenance voltage or high-voltage lighting voltage of the photoionization detector, judging whether the active sensitivity compensation is effective or not, and executing the following steps:
Setting the first step as S1, the second step as S2 and the third step as S3;
if the current value I of the collector response in the calibration period p0 > set PID detection current upper limit I pu Then:
gradually adjusting the current low-voltage maintaining voltage of the PID lamp by the set first step S1, wherein the adjusted low-voltage maintaining voltage=the current low-voltage maintaining voltage-step number N1 is multiplied by the first step S1;
if the regulated low-voltage maintaining voltage is greater than or equal to the low-voltage maintaining voltage lower limit value V kd And the current value I of the collector response in the calibration period acquired again p0 At the set PID detection current upper limit I pu And PID detection current lower limit I pd If yes, judging that the active sensitivity compensation is effective;
if the current low-voltage maintaining voltage of the PID lamp is regulated to be smaller than the lower limit value V of the low-voltage maintaining voltage kd Thereafter, the current value I 'of the collector response is obtained during the calibration period' p0 Is also greater than the set PID detection current upper limit I pu Judging that the active sensitivity compensation is invalid, and prompting equipment failure;
if the set PID basic detection current I p Current value I of collector response in calibration period p0 < set PID detection current lower limit I pd Then:
gradually adjusting the current low-voltage maintaining voltage of the PID lamp by the set second step S2, wherein the adjusted low-voltage maintaining voltage=the current low-voltage maintaining voltage+the step number N2 is multiplied by the second step S2;
If the regulated low-voltage maintenance voltage is less than or equal to the set low-voltage maintenance voltage upper limit value V ku And the current value I 'of the collector response in the calibration period acquired again' p0 At the set PID detection current upper limit I pu And PID detection current lower limit I pd If yes, judging that the active sensitivity compensation is effective;
if the current low-voltage maintaining voltage of the PID lamp is regulated to be larger than the set upper limit value V of the low-voltage maintaining voltage ku Thereafter, the current value I 'of the collector response is obtained during the calibration period' p0 Is also smaller than the set PID detection current lower limit I pd Judging that the active sensitivity compensation is invalid, and prompting to clean the PID lamp;
if the current value I of the collector response in the calibration period p0 Set PID basic detection current I less than or equal to p Then:
gradually adjusting the current high-voltage lighting voltage of the PID lamp by the set third step S3, wherein the adjusted high-voltage lighting voltage=the current high-voltage lighting voltage+the step number N3 is multiplied by the third step S3;
if the regulated high-voltage lighting voltage is less than or equal to the high-voltage lighting voltage upper limit value V lu And the current value I 'of the collector response in the calibration period acquired again' p0 At the set PID detection current upper limit I pu And PID detection current lower limit I pd If yes, judging that the active sensitivity compensation is effective;
If the high-voltage lighting voltage of the PID lamp is adjusted to be greater than the set high-voltage lighting voltage upper limit value V lu After that, the acquired calibration timeCurrent value I 'of in-segment collector response' p0 The PID basic detection current I is smaller than or equal to the set value p And judging that the active sensitivity compensation is invalid, and prompting that the PID lamp is bad.
7. A computer-readable storage medium, wherein a photo-ionization detector active sensitivity compensation program is stored on the computer-readable storage medium, which when executed by a processor, implements the steps of the photo-ionization detector active sensitivity compensation method of claim 1.
8. A computer-readable storage medium, wherein a photo-ionization detector active sensitivity compensation program is stored on the computer-readable storage medium, which when executed by a processor, implements the steps of the photo-ionization detector active sensitivity compensation method of claim 6.
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Citations (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54130965A (en) * | 1978-04-03 | 1979-10-11 | Yokogawa Hokushin Electric Corp | Resistance measuring circuit of automatically temperature compensated type |
| JPH08223786A (en) * | 1995-02-16 | 1996-08-30 | Omron Corp | Motor lock detecting device, power window drive controller using said device, and sun-roof drive controller |
| US5773833A (en) * | 1996-03-22 | 1998-06-30 | Rae Systems, Inc. | Photo-ionization detector for volatile gas measurement |
| KR19990010997A (en) * | 1997-07-21 | 1999-02-18 | 윤종용 | Dark output compensation circuit and method by temperature of CCD |
| DE19828903A1 (en) * | 1998-06-18 | 2000-01-05 | Inst Umwelttechnologien Gmbh | Photoionization detector used especially in trace gas analysis for selective detection of air pollutants |
| EP1285830A2 (en) * | 2001-08-16 | 2003-02-26 | Hella KG Hueck & Co. | Method for compensating the temperature influence on the sending capacity of a LED-transmitter and/or on the sensitivity of a receiver |
| US6967485B1 (en) * | 2003-06-27 | 2005-11-22 | Rae Systems, Inc. | Automatic drive adjustment of ultraviolet lamps in photo-ionization detectors |
| CN102565183A (en) * | 2010-11-30 | 2012-07-11 | 通用电气公司 | Photo-ionization detectors and associated methods thereof |
| CN103424465A (en) * | 2013-07-26 | 2013-12-04 | 华瑞科学仪器(上海)有限公司 | Intelligent PID sensor module |
| KR20140014568A (en) * | 2012-07-25 | 2014-02-06 | (주)아르델 | Apparatus for reducing power based active power filter and method for managing power reduction thereof |
| CN106124609A (en) * | 2016-08-05 | 2016-11-16 | 王宏盘 | Double light path photoionization gas detector and detector |
| CN107834847A (en) * | 2016-08-31 | 2018-03-23 | 杰华特微电子（张家港）有限公司 | The control circuit and control method of a kind of on-off circuit, switching power circuit |
| CN111006979A (en) * | 2019-11-05 | 2020-04-14 | 天津航空机电有限公司 | Circuit and method for smoke detector environment compensation |
| CN111122693A (en) * | 2019-12-23 | 2020-05-08 | 北京华泰诺安探测技术有限公司 | Photoionization detector and method for dynamically adjusting measuring range of detector |
| CN111983004A (en) * | 2019-05-24 | 2020-11-24 | 霍尼韦尔国际公司 | Method, apparatus and system for providing a voltage supply for a photoionization detector lamp |
| CN112697976A (en) * | 2020-12-18 | 2021-04-23 | 汉威科技集团股份有限公司 | Gas path flow real-time dynamic adjusting method, system and storage medium |
| CN113267553A (en) * | 2021-05-19 | 2021-08-17 | 杭州春来科技有限公司 | Environmental air quality monitoring system |
-
2021
- 2021-10-28 CN CN202111261666.9A patent/CN114113293B/en active Active
Patent Citations (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54130965A (en) * | 1978-04-03 | 1979-10-11 | Yokogawa Hokushin Electric Corp | Resistance measuring circuit of automatically temperature compensated type |
| JPH08223786A (en) * | 1995-02-16 | 1996-08-30 | Omron Corp | Motor lock detecting device, power window drive controller using said device, and sun-roof drive controller |
| US5773833A (en) * | 1996-03-22 | 1998-06-30 | Rae Systems, Inc. | Photo-ionization detector for volatile gas measurement |
| KR19990010997A (en) * | 1997-07-21 | 1999-02-18 | 윤종용 | Dark output compensation circuit and method by temperature of CCD |
| DE19828903A1 (en) * | 1998-06-18 | 2000-01-05 | Inst Umwelttechnologien Gmbh | Photoionization detector used especially in trace gas analysis for selective detection of air pollutants |
| EP1285830A2 (en) * | 2001-08-16 | 2003-02-26 | Hella KG Hueck & Co. | Method for compensating the temperature influence on the sending capacity of a LED-transmitter and/or on the sensitivity of a receiver |
| US6967485B1 (en) * | 2003-06-27 | 2005-11-22 | Rae Systems, Inc. | Automatic drive adjustment of ultraviolet lamps in photo-ionization detectors |
| CN102565183A (en) * | 2010-11-30 | 2012-07-11 | 通用电气公司 | Photo-ionization detectors and associated methods thereof |
| KR20140014568A (en) * | 2012-07-25 | 2014-02-06 | (주)아르델 | Apparatus for reducing power based active power filter and method for managing power reduction thereof |
| CN103424465A (en) * | 2013-07-26 | 2013-12-04 | 华瑞科学仪器(上海)有限公司 | Intelligent PID sensor module |
| CN106124609A (en) * | 2016-08-05 | 2016-11-16 | 王宏盘 | Double light path photoionization gas detector and detector |
| CN107834847A (en) * | 2016-08-31 | 2018-03-23 | 杰华特微电子（张家港）有限公司 | The control circuit and control method of a kind of on-off circuit, switching power circuit |
| CN111983004A (en) * | 2019-05-24 | 2020-11-24 | 霍尼韦尔国际公司 | Method, apparatus and system for providing a voltage supply for a photoionization detector lamp |
| CN111006979A (en) * | 2019-11-05 | 2020-04-14 | 天津航空机电有限公司 | Circuit and method for smoke detector environment compensation |
| CN111122693A (en) * | 2019-12-23 | 2020-05-08 | 北京华泰诺安探测技术有限公司 | Photoionization detector and method for dynamically adjusting measuring range of detector |
| CN112697976A (en) * | 2020-12-18 | 2021-04-23 | 汉威科技集团股份有限公司 | Gas path flow real-time dynamic adjusting method, system and storage medium |
| CN113267553A (en) * | 2021-05-19 | 2021-08-17 | 杭州春来科技有限公司 | Environmental air quality monitoring system |
Non-Patent Citations (5)
| Title |
|---|
| Augmented Switching Linear Dynamical System Model for Gas Concentration Estimation with MOX Sensors in an Open Sampling System;Enrico Di Lello 等;《Sensors》(第14期);12533-12559 * |
| 便携式光离子化检测器研究;亢敏;;科技创新导报(02);2 * |
| 基于VOC检测的光离子化检测器的实验研究;周琪;张思祥;周围;王晓辰;李志东;;传感器与微系统(02);39-41 * |
| 机场油库油品泄漏监测的无线传感器节点设计;陈祥勇;《油气储运》;第34卷(第7期);779-783 * |
| 用于挥发性有机化合物总量检测的光离子化检测器电离室的设计;张驭风;魏庆农;张伟;;分析仪器(02);13-17 * |
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