A bag method VOC pre-treatment device and its use method

Abstract

The present invention relates to the field of VOC processing and monitoring technology, and specifically to a bag method VOC pre-treatment device and a method of using the same, including a processing device, a control device, an air intake channel and an exhaust channel, the processing device including a heating box, a sampling bag, and no less than 2 sampling bags; the sampling bag is placed in the heating box and connected to the pressure sensor, the air intake channel and the exhaust channel respectively through a gas path device; the air intake channel includes a gas source interface, a gas purifier, MFC1, and a solenoid valve in sequence, and the exhaust channel includes a vacuum pump, a buffer, a solenoid valve, a VOC detector connected in parallel with the solenoid valve, and MFC2 and a solenoid valve in sequence; the control device includes a PLC controller, a relay, a touch screen, and a wireless communication device, so as to solve the technical defects of the bag method monitoring device in the prior art, such as the low degree of automation, the easy rupture of the sampling bag, the inability to calculate the dead volume of the sample, and the inability to process multiple samples at the same time. Provided is an invention with fully automated control, remote communication alarm, and simultaneous monitoring of multiple samples.

Description

Technical Field

[0001] The present invention relates to the field of VOC pre-treatment monitoring, and in particular to a bag method VOC pre-treatment device and a use method thereof. Background Art

[0002] With the continuous improvement of people's living standards, the hazards of toxic and harmful pollutants in daily life have attracted widespread attention. Among them, aldehydes and ketones, VOCs, etc. emitted by automobile parts are the main sources of indoor air pollution in automobiles. Excessive pollutants have become an important factor affecting people's health. At present, the VOC detection of automobile parts mainly adopts the bag method, and the relevant national departments are formulating the detection standards for VOC of parts. Its working principle is as follows: the sample to be tested is placed in a TEDLAR sampling bag of a certain specification. The sampling bag itself is required to contain no VOC, and the sealed sampling bag is accurately filled with a certain amount of nitrogen. It is placed in an oven and heated at a specified temperature and time. The sampling is carried out with Tenax tubes and DNPH tubes. The Tenax tube is measured by thermal desorption-mass spectrometry, and the DNPH tube is eluted with acetonitrile and the eluent is tested with a liquid chromatograph.

[0003] The testing devices currently on the market have the following main defects: 1. Manual monitoring and control are required, which consumes a lot of manpower and material resources; 2. The volume control accuracy of the gas filled is not high, which does not meet the requirements of the experiment; 3. The heating equipment of the experimental chamber is also relatively simple, and the heating program cannot effectively control the temperature uniformity and stability. The sampling bag is easy to break during cleaning and inflation; 4. The VOC content of multiple samples cannot be monitored at the same time. 5. The dead volume of the sample cannot be calculated. Summary of the invention

[0004] Aiming at the technical defects of the existing bag method monitoring device, such as low automation, easy rupture of the sampling bag, inability to calculate the dead volume of the sample, and inability to process multiple samples at the same time, the present invention provides a new bag method VOC pretreatment device and a method of using the same, which has the performance of full automatic control, remote communication alarm, and simultaneous processing of multiple samples.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A bag method VOC pre-treatment device, comprising a treatment device, a control device, an air intake channel and an exhaust channel,

[0007] The processing device includes a heating box and a sampling bag, the number of the sampling bags is greater than or equal to 2, and the sampling bags are placed in the heating box and are respectively connected to a pressure sensor, an air inlet channel and an exhaust channel through an air path device;

[0008] The air inlet channel includes a gas source interface, a gas purifier, MFC1, and a solenoid valve in sequence, and the exhaust channel includes a vacuum pump, a buffer, a solenoid valve, a VOC detector connected in parallel with the solenoid valve, and MFC2 and a solenoid valve in sequence;

[0009] The control device includes a PLC controller, a relay, a touch screen, and a wireless communication device.

[0010] As a further improvement, the sampling bag is provided with a plurality of gas path device interfaces.

[0011] As a further improvement, the output end of the PLC is electrically connected to the touch screen and the input end of the communication device, the input end of the PLC is connected to the pressure sensor, the solenoid valve, the heating box, the gas source interface, the gas purifier and the MFC, and the PLC controller is also connected to a buzzer alarm device.

[0012] As a further improvement, the wireless communication device includes an AIR200 SMS device connected to an external terminal device for transmission.

[0013] A bag method for VOC pretreatment includes the following steps:

[0014] S1 Bag aging method: Open the heating box to heat and bake the sampling bag, and the PLC controller starts the "sampling bag inflation" program according to the set volume. After heating to the set time, start the "VOC detection of sampling bag" program. When the VOC detection value does not meet the experimental requirements, the "sampling bag A (B) vacuum" and "sampling bag A (B) inflation" are cycled until the VOC detection value meets the requirements, and the aging of sampling bag A (B) is automatically completed;

[0015] S2 leak detection method:

[0016] (1) Negative pressure leak detection: The PLC turns on the "sampling bag negative pressure leak detection mode" and pumps the sampling bag to be tested to the set negative pressure value. The vacuum pump stops working, and the PLC reads the pressure sensor value and starts timing. When the timer reaches the preset time, the pressure value after the leakage rate is completed is read. The bag leakage rate is calculated to determine whether the bag is leaking;

[0017] (2) Positive pressure leak detection: The PLC turns on the "sampling bag positive pressure leak detection mode" and fills the sampling bag with gas. When the set pressure is reached, the buffer is closed and the timing starts. When the timer reaches the set time, the PLC reads the pressure sensor value (P2) and calculates the bag leakage rate to determine whether the bag is leaking.

[0018] S3 cleaning method: put the sample into the sampling bag, and the PLC starts the "sampling bag vacuuming" program. When the set pressure is reached, the PLC starts the "sampling bag filling" program. The gas in the bag is replaced by multiple cycles of vacuuming and filling. When the number of cycles reaches the set number, the cleaning is automatically completed;

[0019] S4 inflation method: put the sample into the sampling bag, and the PLC starts the "sampling inflation" program. When the inflation volume reaches the set volume, the inflation is automatically completed;

[0020] S5 dead volume monitoring method: Put the sample to be tested into the sampling bag and seal it. The PLC starts the "dead volume detection of sampling bag" program. When the vacuum pump draws the bag to the set vacuum pressure, the vacuum pump stops working. Turn on MFC1 and inflate the bag according to the set inflation volume. After completion, record the vacuum pressure value. The PLC processes and calculates the received information to obtain the dead volume of the sample.

[0021] As a further improvement, the negative pressure leak detection calculation formula of the S2 leak detection method is:

[0022] Q = (P2-P1) ÷ P0 × V ÷ t,

[0023] The negative pressure leak detection calculation formula of the S2 leak detection method is:

[0024] Q=(P1-P2)÷101325pa×V÷t×1000,

[0025] Among them, Q-leakage rate (ml / min), P1-leak detection starting pressure setting value (pa), P2-leak detection ending pressure setting value (pa), P0-standard atmospheric pressure (101325pa), V-buffer volume (ml), t-leak detection time (min).

[0026] As a further improvement, the calculation formula of the S5 monitoring dead volume method is:

[0027] V0=V1÷(P1-P2)×P0,

[0028] Among them, V0-sample dead volume (L), P1-test start pressure setting value (pa), P2-test end pressure setting value (pa), P0-standard atmospheric pressure (101325pa), V1-inflated volume (L).

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] Effect 1: The processing device of the present invention includes a heating box and a sampling bag. The number of sampling bags is not less than 2, and they are respectively connected to the pressure sensor, the air inlet channel and the exhaust channel through the air path device. The processing device is provided with multiple channels and can process 2 or more samples at the same time, which greatly saves the processing time;

[0031] Effect 2: The present invention provides a plurality of gas path device interfaces on the sampling bag, which can be connected to the external air intake device and the exhaust device, and can also be connected to the pressure sensor. At the same time, the output end of the pressure sensor is connected to the PLC. When the pressure in the sampling bag is too high, the detection can be completed automatically to prevent the sampling bag from being damaged due to the excessive pressure.

[0032] Effect three, the present invention uses a PLC controller to control the pressure sensor, solenoid valve, heating box, gas source interface, gas purifier and touch screen, realizing full automatic control of the processing device, reducing the labor cost in the traditional detection process, greatly shortening the time and saving costs;

[0033] Effect 4: The present invention is provided with a wireless communication device, which can remotely control the bag method pre-treatment device, monitor the abnormality of the device in real time, and the AIR200 SMS device connected to the external terminal device transmits the abnormal short message to the designated mobile terminal;

[0034] Effect five, the present invention can automatically detect the dead volume of the sample. The principle of traditional bag method VOC detection is to put the sample into a sampling bag of a certain specification, use a vacuum pump to extract the residual gas, and then accurately fill it with a certain amount of gas. Because irregular samples have certain dead angles, it is impossible to completely extract the residual gas, which will cause errors in the control accuracy of the total volume of gas in the bag during the experiment, thereby affecting the concentration of the sample and further affecting the accuracy of the test results. Therefore, it is particularly important to monitor the dead volume of the sample before monitoring the volume;

[0035] Effect six: The present invention is equipped with an alarm device, including a buzzer fault alarm, which can simultaneously alarm for excessive pressure, leakage and inflation flow deviation of the sampling bag, making it convenient for staff to adjust abnormal situations in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is the overall structural diagram of the present invention;

[0037] Figure 2 A table showing the working relationship between sampling bag A and sampling bag B in the embodiment;

[0038] In the figure, 1-heating box, 2-sampling bag A, 3-sampling bag B, 4-gas path device, 5-solenoid valve 1, 6-solenoid valve 2, 7-solenoid valve 3, 8-solenoid valve 4, 9-solenoid valve 5, 10-solenoid valve 6, 11-solenoid valve 7, 12-pressure sensor, 13-VOC detector, 14-MFC2, 15-buffer, 16-vacuum pump, 17-MFC1, 18-gas purifier, 19-gas source interface, 20-PLC controller. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0040] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0041] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] The present invention is further described in detail below through specific implementation examples in conjunction with the accompanying drawings. Example

[0043] This embodiment provides a bag method VOC pre-treatment device, such as Figure 1 As shown, it is a block diagram of the overall structure of the present invention, including a processing device, a control device, an intake passage and an exhaust passage.

[0044] The processing device includes a heating box 1 and a sampling bag. The number of sampling bags in this embodiment is 2, namely sampling bag A2 and sampling bag B3. The sampling bag A2 and sampling bag B3 are placed in the heating box 1 and are respectively connected to the pressure sensor 12, the air intake channel and the exhaust channel through the air path device 4; two air path device interfaces are provided on the sampling bag A2, one is connected to the pressure sensor 12 through the solenoid valve 6-10, and the other is connected to the air intake channel and the exhaust channel through the solenoid valve 1-5 and the solenoid valve 4-8 respectively; the sampling bag B3 is also provided with two air path device interfaces, one is connected to the pressure sensor 12 through the solenoid valve 5-9, and the other is connected to the air intake channel and the exhaust channel through the solenoid valve 2-6 and the solenoid valve 3-7 respectively; the solenoid valve 1-5 and the solenoid valve 2-6 are connected to the air path device together with the MFC1-17, the gas purifier 18, and the gas source interface 19, and the solenoid valve 7-11 is connected in parallel with the VOC detector 13 and MFC214.

[0045] The air inlet channel includes a gas source interface 19, a gas purifier 18, an MFC 117, and a solenoid valve in sequence, and the exhaust channel includes a vacuum pump 16, a buffer 15, a solenoid valve, a VOC detector 13 connected in parallel with the solenoid valve, and MFC2-14 and a solenoid valve in sequence;

[0046] The control device includes a PLC controller 20, a relay, a touch screen, and a wireless communication device.

[0047] As a further improvement, the sampling bag is provided with a plurality of gas path device 4 interfaces.

[0048] As a further improvement, the output end of the PLC controller 20 is electrically connected to the touch screen and the input end of the communication device, the input end of the PLC controller 20 is connected to the pressure sensor 12, the solenoid valve, the heating box 1, the gas source interface 19, the gas purifier 18 and the MFC, and the PLC controller 20 is also connected to a buzzer alarm device.

[0049] As a further improvement, the wireless communication device includes an AIR200 SMS device connected to an external terminal device for transmission.

[0050] This embodiment also provides a bag method for VOC pretreatment, comprising the following steps:

[0051] S1 Bag aging method: Open the heating box to heat and bake the sampling bag, and the PLC controller starts the "sampling bag A (B) filling" program according to the set volume. After heating to the set time, start the "VOC detection of sampling bag A (B)" program. When the VOC detection value does not meet the experimental requirements, the "sampling bag A (B) vacuum" and "sampling bag A (B) filling" are cycled until the VOC detection value meets the requirements, and the aging of sampling bag A (B) is automatically completed;

[0052] S2 leak detection method:

[0053] (1) Negative pressure leak detection: PLC turns on the "sampling bag A (B) negative pressure leak detection mode", pumps the sampling bag A (B) to be tested to the set negative pressure value, the vacuum pump stops working, and the PLC reads the pressure sensor value and starts timing. When the timer reaches the preset time, it reads the pressure value after the leakage rate is completed, and calculates the bag leakage rate to determine whether the bag is leaking;

[0054] (2) Positive pressure leak detection: PLC turns on the "sampling bag A (B) positive pressure leak detection mode" and fills the sampling bag with gas. When the set pressure is reached, the buffer is closed and the timing starts. When the timer reaches the set time, the PLC reads the pressure sensor value (P2) and calculates the bag leakage rate to determine whether the bag is leaking.

[0055] S3 cleaning method: put the sample into sampling bag A (B), and the PLC starts the "sampling bag vacuuming" program. When the set pressure is reached, the PLC starts the "sampling bag filling" program. The gas in the bag is replaced by multiple cycles of vacuuming and filling. When the number of cycles reaches the set number, the cleaning is automatically completed;

[0056] S4 inflation method: Place the sample into sampling bag A (B), and the PLC starts the "sampling inflation" program. When the inflation volume reaches the set volume, inflation is automatically completed;

[0057] S5 dead volume detection method: put the sample to be tested into sampling bag A (B) and seal it, PLC starts the "sampling bag dead volume detection" program, when the vacuum pump draws the bag to the set vacuum pressure, the vacuum pump stops working. Turn on MFC1, inflate the bag according to the set inflation volume, record the vacuum pressure value after completion, and PLC processes and calculates the received information to obtain the dead volume of the sample. The principle of bag method VOC detection is to put the sample into a sampling bag of a certain specification, use a vacuum pump to extract the residual gas. Accurately fill a certain amount of gas. The traditional bag method VOC detection principle is to put the sample into a sampling bag of a certain specification, use a vacuum pump to extract the residual gas, and then accurately fill a certain amount of gas. Because irregular samples have certain dead angles, it is impossible to completely extract the residual gas, which will cause errors in the control accuracy of the total volume of gas in the bag during the experiment, thereby affecting the concentration of the sample, and then affecting the accuracy of the test results. Therefore, it is particularly important to monitor the dead volume of the sample before monitoring the volume.

[0058] As a further improvement, the negative pressure leak detection calculation formula of the S2 leak detection method is:

[0059] Q = (P2-P1) ÷ P0 × V ÷ t,

[0060] The negative pressure leak detection calculation formula of the S2 leak detection method is:

[0061] Q=(P1-P2)÷101325pa×V÷t×1000,

[0062] Among them, Q-leakage rate (ml / min), P1-leak detection starting pressure setting value (pa), P2-leak detection ending pressure setting value (pa), P0-standard atmospheric pressure (101325pa), V-buffer volume (ml), t-leak detection time (min).

[0063] As a further improvement, the calculation formula of the S5 monitoring dead volume method is:

[0064] V0=V1÷(P1-P2)×P0,

[0065] Among them, V0-sample dead volume (L), P1-test start pressure setting value (pa), P2-test end pressure setting value (pa), P0-standard atmospheric pressure (101325pa), V1-inflated volume (L).

[0066] like Figure 2 As shown, it is a table of the working relationship between the sampling bag A and the sampling bag B in the embodiment, which lists the switching conditions of the solenoid valve during the processes of aging, leak detection, cleaning, inflation and dead volume monitoring.

[0067] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for using a bag-based VOC pretreatment device, characterized in that: It comprises a processing device, a control device, an air intake channel and an exhaust channel; the processing device comprises a heating box (1) and a sampling bag, the number of the sampling bags being greater than or equal to 2, the sampling bags being placed in the heating box (1) and connected to a pressure sensor (12), an air intake channel and an exhaust channel respectively through an air path device (4); the air intake channel comprises a gas source interface (19), a gas purifier (18), an MFC1 (17), and an electromagnetic valve 1 (5) in sequence, the exhaust channel comprises a vacuum pump (16), a buffer (15), an electromagnetic valve 7 (11) and an electromagnetic valve 4 (8) in sequence, and the exhaust channel further comprises a VOC detector (13) and an MFC2 (14) connected in parallel with the electromagnetic valve 7 (11); The control device comprises a PLC controller (20), a relay, a touch screen, and a wireless communication device; The sampling bag is provided with a plurality of gas path device (4) interfaces; The output end of the PLC controller (20) is electrically connected to the touch screen and the input end of the communication device, the input end of the PLC controller (20) is connected to the pressure sensor (12), the solenoid valve, the heating box (1), the gas source interface (19), the gas purifier (18) and the MFC, and the PLC controller (20) is also connected to a buzzer alarm device; The wireless communication device includes an AIR200 text messaging device that connects to an external terminal device for transmission; The bag method VOC pre-treatment method comprises the following steps: S1 Bag aging method: Open the heating box to heat and bake the sampling bag, and the PLC controller starts the "sampling bag inflation" program according to the set volume; after heating to the set time, start the "sampling bag VOC detection" program; when the VOC detection value does not reach the experimental requirement, cycle through the "sampling bag vacuum" and "sampling bag inflation" until the VOC detection value reaches the requirement, and the sampling bag aging is automatically completed; S2 leak detection method: (1) Negative pressure leak detection: The PLC turns on the "sampling bag negative pressure leak detection mode" and pumps the sampling bag to be tested to the set negative pressure value. The vacuum pump stops working, and the PLC reads the pressure sensor value and starts timing. When the timer reaches the preset time, the pressure sensor value is read again, and the bag leakage rate is calculated to determine whether the bag is leaking; (2) Positive pressure leak detection: PLC turns on the "sampling bag positive pressure leak detection mode" and fills the sampling bag with gas. When the set pressure is reached, the buffer is closed and the timing starts. When the timer reaches the set time, the PLC reads the pressure sensor value and calculates the bag leakage rate to determine whether the bag is leaking. S3 cleaning method: put the sample into the sampling bag, and the PLC starts the "sampling bag vacuuming" program; when the set pressure is reached, the PLC starts the "sampling bag filling" program; the gas in the bag is replaced by multiple cycles of vacuuming and filling, and the cleaning is automatically completed when the number of cycles reaches the set number; S4 inflation method: put the sample into the sampling bag, and the PLC starts the "sampling inflation" program; when the inflation volume reaches the set volume, the inflation is automatically completed; S5 dead volume monitoring method: put the sample to be tested into the sampling bag and seal it, the PLC starts the "sampling bag dead volume detection" program, when the vacuum pump draws the bag to the set vacuum pressure, the vacuum pump stops working; turn on MFC1, inflate the bag according to the set inflation volume, record the vacuum pressure value after completion, the PLC processes and calculates the received information to obtain the dead volume of the sample.

2. The method for using the bag method VOC pretreatment device according to claim 1, characterized in that: The negative pressure leak detection calculation formula of the S2 leak detection method is: Q = (P2-P1) ÷ P0 × V ÷ t, Among them, Q-leakage rate (ml / min), P1-leak detection starting pressure setting value (pa), P2-leak detection ending pressure setting value (pa), P0-standard atmospheric pressure (101325pa), V-buffer volume (ml), t-leak detection time (min).

3. The method for using the bag method VOC pretreatment device according to claim 1, characterized in that: The calculation formula of the S5 monitoring dead volume method is: V0=V1÷(P1-P2)×P0, Among them, V0-sample dead volume (L), P1-test start pressure setting value (pa), P2-test end pressure setting value (pa), P0-standard atmospheric pressure (101325pa), V1-inflated volume (L).

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