CN111289309A - Automatic sampling device and method for VOC in automobile - Google Patents

Abstract

The invention discloses an automatic sampling device and method for VOC in a vehicle. The device comprises a controller and a plurality of sampling channels; each sampling channel comprises a constant-current sampling pump, a gas pressure sensor, an electromagnetic valve, a gas flow switch and a sampling bag which are sequentially connected through a gas guide tube; the constant-current sampling pump, the gas pressure sensor, the electromagnetic valve and the gas flow switch are respectively and electrically connected with the controller; the constant-current sampling pump is provided with a VOC suction pipe. The invention realizes the automatic sampling of VOC in the automobile, and can measure and display parameters such as flow, volume, air pressure, sampling time and the like of the sampled gas in real time in the sampling process. The problems that time and labor are wasted, sampling time, gas pressure, flow and the like are difficult to control accurately and the like in the conventional manual sampling are solved.

Description

Automatic sampling device and method for VOC in automobile

Technical Field

The invention belongs to the field of monitoring of air quality in an automobile, and particularly relates to an automatic sampling device and method for VOC (volatile organic compounds) in the automobile.

Background

With the research on air pollution in the automobile, people pay more and more attention to the quality of air in the automobile. VOC from automobile interior parts and materials are a main cause of affecting the quality of air in a vehicle. At present, a bag method is adopted for monitoring VOC of automobile parts in host factories and laboratories at home and abroad to carry out a test, namely, gas collected from an automobile body is filled into a bag. The method has accurate requirements on the collected pump flow, the collected time, the sampled volume and the like, and the accuracy of the final detection result is directly influenced if the requirements are not met. The current acquisition process of the method is manually operated, so that the test efficiency is low, more importantly, accurate quantification and real-time monitoring are difficult to achieve, and artificial operation errors are easy to occur.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides an automatic sampling device and method for VOC in a vehicle.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides an automatic sampling device for VOC in a vehicle, which comprises a controller and a plurality of sampling channels. Each sampling channel comprises a constant-current sampling pump, a gas pressure sensor, an electromagnetic valve, a gas flow switch and a sampling bag which are sequentially connected through a gas guide tube. The constant-current sampling pump, the gas pressure sensor, the electromagnetic valve and the gas flow switch are respectively and electrically connected with the controller. The constant-current sampling pump is provided with a VOC suction pipe.

Further, the number of sampling channels is 3.

Further, the air guide pipe is a polytetrafluoroethylene pipe.

Further, the VOC drinking straw comprises: one DNPH tube (aldehyde ketone collecting tube) for adsorbing aldehyde ketone substances and two TENAX tubes (benzene series collecting tube) for adsorbing benzene substances.

Further, the device also comprises a display electrically connected with the controller.

Furthermore, the device also comprises an audible and visual alarm module electrically connected with the controller.

The invention also provides a method for automatically sampling the VOC in the automobile by using the device, which comprises the following steps:

step 1, a sampling bag is arranged at a sampling position in a vehicle, and a VOC suction pipe is arranged on a constant-current sampling pump. The controller is powered on to run an initialization program, and the electromagnetic valve and the gas flow switch are both in an off state.

And 2, opening all the vehicle windows and doors, and setting the delay time of the test preparation.

And step 3, after the test preparation delay time is reached, closing all the vehicle window doors and setting the test closing delay time.

And 4, automatically entering a sampling stage under the control of a controller after the test closed delay time is reached: and starting the constant-current sampling pump, and when the air pressure value measured by the air pressure sensor is reduced to a set threshold value, starting the electromagnetic valve and the air flow switch and starting timing. And measuring the pressure, flow and volume of the sampled gas in real time.

And 5, after the set sampling time is reached, closing the electromagnetic valve, the gas flow switch and the constant-current sampling pump by the controller.

Compared with the prior art, the invention has the following beneficial effects:

the invention provides an automatic sampling device for VOC in an automobile, which is characterized in that a controller and a plurality of sampling channels are arranged, each sampling channel comprises a constant-current sampling pump, a gas pressure sensor, an electromagnetic valve, a gas flow switch and a sampling bag which are sequentially connected through a gas guide tube, the constant-current sampling pump, the gas pressure sensor, the electromagnetic valve and the gas flow switch are respectively and electrically connected with the controller, a VOC suction tube is arranged on the constant-current sampling pump, the automatic sampling of the VOC in the automobile is realized, and parameters such as flow, volume, gas pressure, sampling time and the like of sampled gas can be measured and displayed in real time in the sampling process. The invention solves the problems of time and labor waste, difficulty in accurately controlling sampling time, gas pressure, flow and the like in the conventional manual sampling and the like.

Drawings

Fig. 1 is a schematic structural diagram of an automatic sampling device for VOC in a vehicle according to an embodiment of the present invention.

In the figure: the method comprises the following steps of 1-a controller, 2-a constant-flow sampling pump, 3-a gas pressure sensor, 4-an electromagnetic valve, 5-a gas flow switch and 6-a sampling bag.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The schematic structural diagram of the automatic sampling device for the VOC in the automobile provided by the embodiment of the invention is shown in figure 1, and the automatic sampling device comprises a controller 1 and a plurality of sampling channels. Each sampling channel comprises a constant-current sampling pump 2, a gas pressure sensor 3, an electromagnetic valve 4, a gas flow switch 5 and a sampling bag 6 which are sequentially connected through a gas guide tube. The constant-current sampling pump 2, the gas pressure sensor 3, the electromagnetic valve 4 and the gas flow switch 5 are respectively and electrically connected with the controller 1. The constant-current sampling pump 2 is provided with a VOC suction pipe.

In the present embodiment, the apparatus is mainly composed of a controller 1 and a plurality of sampling channels. The controller 1 is mainly used for data processing and electrical control, and realizes automatic sampling of VOC in the automobile under the control of the controller. The controller 1 may be a microprocessor or a PLC programmable controller. Each sampling channel mainly comprises a constant-current sampling pump 2, a gas pressure sensor 3, an electromagnetic valve 4, a gas flow switch 5 and a sampling bag 6. The sampling bag 6 is a sealing bag for containing gas to be sampled, and in order not to influence the measurement accuracy of VOC in the vehicle, the sampling bag 6 needs to be made of a material which does not contain VOC, such as polytetrafluoroethylene. The constant-flow sampling pump 2 is used for pumping out the gas in the sampling bag 6, and the constant-flow sampling pump 2 is provided with a VOC suction pipe for adsorbing VOC contained in the gas. The constant-flow sampling pump 2 can realize constant-flow sampling, namely the flow rate (the volume of gas flowing through per unit time) of the extracted gas is constant, and different flow rates can be set under the action of the controller 1. Therefore, the gas volume can be calculated by knowing the sampling time, and the VOC concentration of the sampled gas, generally in milligrams per cubic meter, can be obtained by detecting the mass of VOC adsorbed on the VOC suction pipe. The gas pressure sensor 3 is used for measuring gas pressure, and can judge whether the vacuum degree required by the test is achieved or not by comparing with a set threshold value; the pressure of the sampled gas may also be measured in real time. The electromagnetic valve 4 is used for opening or closing the sampling channel under the action of the controller 1. The gas flow switch 5 is used for measuring the volume of the sampling gas flowing from the starting moment in real time under the action of the controller 1, and can also be used for measuring the volume of the sampling gas in the sampling process.

Preferably, the constant-current sampling pump 2 can be a Gilibrator3 type sampling pump, the gas pressure sensor 3 can be a Pse533-R06-C2L type sensor, the electromagnetic valve 4 can be a VX214FA type two-way straight-through vacuum electromagnetic valve, and the gas flow switch 5 can be a PF2A721-03-27 type integrated digital flow switch.

The embodiment realizes the automatic sampling of the VOC in the automobile, and can measure and display parameters such as flow, volume, air pressure, sampling time and the like of the sampled gas in real time in the sampling process. The problems that time and labor are wasted, sampling time, gas pressure, flow and the like are difficult to control accurately and the like in the conventional manual sampling are solved.

As an alternative embodiment, the number of sampling channels is 3.

This example shows an implementation of 3 sampling channels, as shown in fig. 1. This embodiment is merely a preferred embodiment and does not exclude other embodiments with a number of sampling channels.

As an alternative embodiment, the airway tube is a polytetrafluoroethylene tube.

This example shows an embodiment of the airway tube, which uses a teflon tube. The polytetrafluoroethylene tube is characterized by not containing VOC, and the measuring precision of VOC concentration is not influenced by the polytetrafluoroethylene tube adopted as the air duct. This example is merely a preferred embodiment and does not exclude other embodiments that do not contain VOCs.

As an alternative embodiment, the VOC drinking straw comprises: one DNPH tube for adsorbing aldehyde ketone substances and two TENAX tubes for adsorbing benzene substances.

This example shows an embodiment of a VOC straw that uses one DNPH tube for adsorbing aldehydes and ketones and two TENAX tubes for adsorbing benzenes.

As an alternative embodiment, the device further comprises a display electrically connected to the controller 1.

In this embodiment, a display electrically connected to the controller 1 is further provided, and is mainly used for displaying parameters such as sampling time, gas pressure, volume, and flow rate.

As an alternative embodiment, the device further comprises an audible and visual alarm module electrically connected to the controller 1.

In this embodiment, an audible and visual alarm module electrically connected to the controller 1 is further provided, and is mainly used for giving an audible and visual alarm to prompt when sampling is completed or a fault occurs.

The invention also provides an embodiment of a method for automatically sampling the VOC in the automobile by using the device, which comprises the following steps:

s101, a sampling bag 6 is arranged at a sampling position in the vehicle, and a VOC suction pipe is arranged on the constant-current sampling pump 2. The controller 1 is powered on to operate an initialization program, and the electromagnetic valve 4 and the gas flow switch 5 are both in an off state;

s102, opening all the vehicle window doors, and setting test preparation delay time;

s103, after the test preparation delay time is reached, closing all the vehicle window doors, and setting the test closing delay time;

s104, automatically entering a sampling stage under the control of the controller 1 after the test closing delay time is reached: and (3) starting the constant-current sampling pump 2, when the air pressure value measured by the air pressure sensor 3 is reduced to a set threshold value, starting the electromagnetic valve 4 and the air flow switch 5, and starting timing. And measuring the pressure, volume and flow of the sampled gas in real time.

And S105, after the set sampling time is reached, closing the electromagnetic valve 4, the gas flow switch 5 and the constant-current sampling pump 2 by the controller 1.

The embodiment provides a method for automatic sampling by applying the device. S101, arranging a sampling bag 6 at a sampling position in a vehicle, installing a VOC (volatile organic compound) suction pipe on a constant-current sampling pump 2, and electrifying and initializing a controller 1. According to the test standard, the VOC concentration in the vehicle within 16 hours needs to be measured, and therefore, the vehicle interior ventilation step S102 and the closing step S103 need to be set. After the closing step is completed, the sampling stage S104 is entered. When the controller 1 is initialized, the electromagnetic valve 4 and the gas flow switch 5 are both in a disconnected state, the sampling pump is started after the sampling stage is started, and air in the gas guide pipe is quickly pumped out. When the pressure value measured by the pressure sensor is reduced to a set threshold value, namely when the air duct is approximately vacuum, the controller 1 outputs a control signal to open the electromagnetic valve 4 and the gas flow switch 5, start sampling and start timing. And parameters such as air pressure, volume, flow and the like of the sampled gas are measured in real time in the sampling process. And S105 is executed after the set sampling time is reached, and the electromagnetic valve 4, the gas flow switch 5 and the constant-current sampling pump 2 are closed. And finishing sampling.

The above description is only for the purpose of illustrating a few embodiments of the present invention, and should not be taken as limiting the scope of the present invention, in which all equivalent changes, modifications, or equivalent scaling-up or down, etc. made in accordance with the spirit of the present invention should be considered as falling within the scope of the present invention.

Claims (7)

1. An automatic VOC sampling device in an automobile is characterized by comprising a controller and a plurality of sampling channels; each sampling channel comprises a constant-current sampling pump, a gas pressure sensor, an electromagnetic valve, a gas flow switch and a sampling bag which are sequentially connected through a gas guide tube; the constant-current sampling pump, the gas pressure sensor, the electromagnetic valve and the gas flow switch are respectively and electrically connected with the controller; the constant-current sampling pump is provided with a VOC suction pipe.

2. The automatic sampling device of VOC in a vehicle of claim 1 wherein said number of sampling channels is 3.

3. The automatic sampling device of VOC in a vehicle of claim 1 wherein said gas conduit is a polytetrafluoroethylene tube.

4. An automatic in-vehicle VOC sampling device as claimed in claim 1, wherein said VOC suction tube comprises: one DNPH tube for adsorbing aldehyde ketone substances and two TENAX tubes for adsorbing benzene substances.

5. The automatic in-vehicle VOC sampling device of claim 1 further comprising a display electrically connected to said controller.

6. The automatic sampling device of VOC in a vehicle of claim 1 further comprising an audible and visual alarm module electrically connected to said controller.

7. A method for automatically sampling VOC in a vehicle using the apparatus of claim 1, comprising the steps of:

step 1, arranging a sampling bag at a sampling position in a vehicle, and installing a VOC (volatile organic compound) suction pipe on a constant-current sampling pump; the controller is powered on to run an initialization program, and the electromagnetic valve and the gas flow switch are both in an off state;

step 2, opening all the vehicle windows and doors, and setting the delay time of test preparation;

step 3, after the test preparation delay time is reached, closing all the vehicle window doors, and setting the test closing delay time;

and 4, automatically entering a sampling stage under the control of a controller after the test closed delay time is reached: starting a constant-current sampling pump, starting an electromagnetic valve and a gas flow switch when the gas pressure value measured by a gas pressure sensor is reduced to a set threshold value, and starting timing; measuring the pressure, flow and volume of the sampled gas in real time;

and 5, after the set sampling time is reached, closing the electromagnetic valve, the gas flow switch and the constant-current sampling pump by the controller.

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