Formaldehyde detection device based on multiple probes

Abstract

The invention relates to the technical field of gas detection, in particular to a formaldehyde detection device based on multiple probes, which comprises a probe main body and a gas detection assembly, the gas detection assembly comprises a butt joint part arranged at the bottom of the probe main body, and a semiconductor gas detection element is arranged in the middle of the butt joint part. A mounting cylinder is arranged on the outer side of the semiconductor gas detection element, and a filtering piece is arranged at the bottom of the mounting cylinder; a heat conducting plate is arranged in the mounting cylinder, is in contact with the semiconductor gas detection element, and is provided with hollow grooves which are symmetrically distributed; and the drainage assembly comprises a heat insulation cylinder arranged at the empty groove, the heat insulation cylinder is fixedly connected with the mounting cylinder, a reciprocating assembly is arranged in the heat insulation cylinder, and the reciprocating assembly is heated through a heat conduction plate, so that reciprocating movement of the reciprocating assembly in the heat insulation cylinder is achieved. By arranging the drainage assembly, the effect of sucking gas at the bottom of the probe main body is achieved, and the formaldehyde detection accuracy of the semiconductor gas detection element is improved.

Description

Technical Field

[0001] The invention relates to the technical field of formaldehyde detection, and in particular to a formaldehyde detection device based on multiple probes. Background Art

[0002] Formaldehyde appears as a colorless gas under normal conditions. When it is at a low concentration level, its presence is often difficult to be directly perceived and is easily obscured by other odors. However, as the concentration increases, formaldehyde will emit a strong irritating and suffocating odor, which will have a significant irritating effect on the human eyes, nose and other organs. If individuals are in a high concentration of formaldehyde environment for a long time, they may experience symptoms such as dizziness, headache, tearing, nausea and vomiting, coughing, chest tightness, etc., and may even induce serious health problems such as leukemia, and in extreme cases, it may lead to death.

[0003] With the increasing public awareness of environmental protection, formaldehyde detection has gradually become a focus of attention from all walks of life. However, most of the formaldehyde detectors currently circulating on the market only have a single detection function and cannot achieve comprehensive monitoring through networking with the master control machine, making it difficult to meet actual needs.

[0004] In response to the above problems, a Chinese patent with application number CN201821373697.7 discloses a toxic gas alarm, including an aluminum alloy explosion-proof shell, and a reinforced cover fixed to the front of the aluminum alloy explosion-proof shell by bolts; a lead-in wire sealing head is provided on one side of the upper part of the aluminum alloy explosion-proof shell, and a sound and light alarm column is installed on the other side through a bolt tube seal; a transparent end cap is installed on the top of the sound and light alarm column; an LED light group is installed on the inside of the transparent end cap; a buzzer group is installed on the inside of the sound and light alarm column; the LED light group and the buzzer group are both electrically connected to a controller; the controller is connected to a gas leak detection circuit through a comparator; the controller is also electrically connected to a toxic gas detection module. The toxic gas alarm adopts an external sound and light alarm circuit; it will not affect the overall waterproof and dustproof performance of the alarm, and the sound and light alarm effect is good; in addition, it adopts gas leakage detection and gas component content detection progressively, and has a good energy-saving effect.

[0005] However, although the above patent design has successfully realized the function of networked monitoring of the master control machine, it still encounters many challenges in actual application scenarios, especially in complex underground space environments such as tunnel construction. Specifically, due to the complexity of the environment, underground spaces such as tunnels are often accompanied by poor ventilation, which not only has a negative impact on the accuracy of alarm detection, but also because the density of formaldehyde is greater than that of air, the current toxic gas alarm generally lacks an effective wind guide structure design, making it difficult to effectively introduce the formaldehyde gas deposited in the lower layer into the detection unit of the alarm, which in turn exacerbates the decline in the accuracy of the alarm.

[0006] In addition, the dust content in the tunnel is high, which poses a long-term and severe challenge to the detection unit of the alarm. The main reason is that the dust in the tunnel can easily penetrate and accumulate inside the detection unit, causing blockage, making it difficult for formaldehyde to effectively enter the detection unit. Even if it enters, its concentration is far lower than normal, which seriously weakens the detection accuracy of the alarm.

[0007] In view of this, it is particularly critical and urgent to develop a formaldehyde detection device based on a multi-probe design that can effectively deal with the above-mentioned technical difficulties. Summary of the invention

[0008] The purpose of the present invention is to provide a formaldehyde detection device based on multiple probes to solve the technical problems raised in the above background technology.

[0009] To achieve the above object, the present invention provides the following technical solutions: A formaldehyde detection device based on multiple probes comprises: a plurality of probe bodies, each of which is provided with a connecting portion on the top, and the connecting portion is used to connect to a control host; a gas detection assembly, which comprises a docking portion arranged at the bottom of the probe body, a semiconductor gas detection element is arranged in the middle of the docking portion, and the concentration of formaldehyde gas is detected; a mounting tube is arranged on the outside of the semiconductor gas detection element, a filter is arranged at the bottom of the mounting tube, and formaldehyde enters the interior of the mounting tube through the filter at the bottom and reacts with the semiconductor gas detection element; a heat conducting plate is arranged inside the mounting tube and contacts the semiconductor gas detection element, and symmetrically distributed empty grooves are arranged on the heat conducting plate; a drainage assembly, which comprises an insulating tube arranged at the empty groove, the insulating tube is fixedly connected to the mounting tube, a reciprocating assembly is arranged inside the insulating tube, the reciprocating assembly is heated by the heat conducting plate, and the reciprocating assembly is moved back and forth inside the insulating tube, so that the formaldehyde gas deposited below the mounting tube is sucked into the mounting tube.

[0010] Preferably, the reciprocating assembly comprises: A magnetic member is arranged inside the docking portion, and its position corresponds to the position of the empty slot; A soft magnetic component is arranged inside the heat-insulating cylinder and is magnetically attracted to the magnetic component. A piston plate is provided at the bottom of the soft magnetic component, and the piston plate is slidably connected to the heat-insulating cylinder. A first elastic member, which is arranged below the piston plate and connected to the bottom of the heat insulation cylinder; The one-way air inlet pipe and the one-way air outlet pipe are both arranged on the top of the heat insulation cylinder, wherein the one-way air outlet pipe is connected with the outer area of ​​the installation cylinder.

[0011] Preferably, a support tube is provided at the bottom of the thermal insulation tube, and the support tube is used to connect the inner area of ​​the thermal insulation tube with the outer area of ​​the installation tube.

[0012] Preferably, the semiconductor gas detection element includes a plurality of connecting pins, and an array of the plurality of connecting pins is distributed on the top of the docking portion, wherein a heating resistor is connected between two opposite connecting pins located in the middle, and an induction resistor is provided on the outside of the heating resistor, and the induction resistor is connected to other connecting pins through a connecting wire.

[0013] Preferably, the heights of the one-way air inlet pipe and the one-way air outlet pipe are not lower than the height of the inductive resistor.

[0014] Preferably, the filter element comprises: An annular plate is arranged inside the mounting cylinder, and a top of the annular plate is connected to the heat-insulating cylinder via a symmetrically arranged second elastic member; The filter screen is arranged in the inner circle area of ​​the annular plate and is used for filtering the gas entering the installation cylinder.

[0015] Preferably, a connecting hose is provided on the outer side of the second elastic member, the connecting hose is connected to an annular groove provided on the one-way air outlet pipe, an elastic membrane is provided on the outer side of the annular groove, and when the elastic membrane is fully expanded, the one-way air outlet pipe is sealed.

[0016] Preferably, a connecting hose is provided at the top of the heat-insulating cylinder, and a pressure valve flap is provided at the connection between the connecting hose and the heat-insulating cylinder; The inner ring of the annular plate is provided with inclined holes distributed in an array, and the inclined holes are all connected with the connecting channel arranged inside the annular plate, and the connecting channel is connected with the connecting hose.

[0017] Preferably, the Curie temperature of the magnetic component is greater than the temperature generated when the heating resistor is working, and the Curie temperature of the soft magnetic component is less than the temperature generated when the heating resistor is working.

[0018] Preferably, an alarm unit is provided on the top of the probe body, and when the formaldehyde value exceeds a preset value, the alarm unit sounds an alarm.

[0019] Technical effects and advantages of the present invention: 1. The present invention provides a docking part and a semiconductor gas detection element, combined with a mounting tube and a filter, to effectively guide the formaldehyde gas to enter and contact and react with the semiconductor gas detection element. Through the coordinated work of the heating resistor and the induction resistor, the formaldehyde concentration change is sensitively sensed and converted into an electrical signal output, which significantly improves the accuracy and reliability of the detection.

[0020] 2. The present invention solves the problem that formaldehyde gas is difficult to effectively introduce into the detection unit in complex scenes by providing a heat conduction plate and a drainage component. The heat conduction plate heats and drives the reciprocating component to move back and forth in the insulation cylinder, thereby improving the circulation efficiency of formaldehyde gas and ensuring that the detection unit accurately captures concentration changes. At the same time, the configuration of the one-way air inlet pipe and the one-way air outlet pipe optimizes the gas flow path and reduces interference and errors.

[0021] 3. The present invention adopts an automatic cleaning mechanism formed by an annular plate, a filter screen and a second elastic member. When the filter screen is partially blocked by dust and causes airflow pressure fluctuations, the annular plate generates vertical vibrations, which not only absorbs impact energy but also automatically cleans the blocked area, thereby extending the service life of the filter screen, ensuring that formaldehyde gas smoothly enters the detection unit, and improving detection stability and accuracy.

[0022] 4. The present invention provides components such as connecting hoses and elastic membranes. When the filter is completely blocked, the gas in the second elastic member enters the annular groove through the connecting hose, causing the elastic membrane to expand and block the one-way air outlet pipe. As the heat conduction plate continues to heat, when the air pressure exceeds the set value of the pressure valve disc, the gas in the insulation cylinder is ejected through the connecting hose to strongly impact and clean the filter, ensuring the continuous and stable operation of the device in complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the main structure of the formaldehyde detection device of the present invention.

[0024] Figure 2 It is a schematic diagram of the structure of the gas detection component of the present invention.

[0025] Figure 3 Schematic diagram of the internal structure of the gas detection component of the present invention.

[0026] Figure 4 It is a structural schematic diagram of the docking portion of the present invention.

[0027] Figure 5 It is a schematic diagram of the distribution structure of the connecting pins of the present invention.

[0028] Figure 6 It is a schematic diagram of the internal structure of the installation cylinder of the present invention.

[0029] Figure 7 It is a schematic structural diagram of the drainage component of the present invention.

[0030] Figure 8 It is a schematic diagram of the cross-sectional structure of the one-way air outlet pipe of the present invention.

[0031] Fig. 9 It is a schematic diagram of the cross-sectional structure of the gas detection component of the present invention.

[0032] Fig.10This is a schematic diagram of a first working state of the gas detection component of the present invention.

[0033] Fig.11 It is a schematic diagram of the second working state of the gas detection component of the present invention.

[0034] Fig.12 It is a schematic diagram of the connection structure between multiple probe bodies and a control host of the present invention.

[0035] The accompanying drawings are marked as follows: 1. Probe body; 2. Connecting part; 3. Alarm department; 4. Gas detection assembly; 401. docking part; 402. mounting tube; 403. connecting pin; 404. heating resistor; 405. induction resistor; 406. filter element; 4061. annular plate; 4062. filter screen; 5. Heat conduction plate; 6. Empty slot; 7. Drainage assembly; 701. Heat insulation cylinder; 702. Magnetic member; 703. Soft magnetic member; 704. Piston plate; 705. First elastic member; 706. One-way air inlet pipe; 707. One-way air outlet pipe; 8. Support pipe; 9. A second elastic member; 10. Connect the hose; 11. Elastic membrane; 12. Connecting hose; 13. Oblique hole. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Embodiment 1 Reference Figure 1-Figure 12 As shown, the present invention provides a formaldehyde detection device based on multiple probes, including a probe body 1 and a gas detection component 4. The gas detection component 4 includes a docking portion 401 arranged at the bottom of the probe body 1, a semiconductor gas detection element is arranged in the middle of the docking portion 401, a mounting tube 402 is arranged on the outer side of the semiconductor gas detection element, and a filter 406 is arranged at the bottom of the mounting tube 402. Formaldehyde enters the interior of the mounting tube 402 through the filter 406 at the bottom and contacts and reacts with the semiconductor gas detection element.

[0038] Specifically, the semiconductor gas detection element includes a plurality of connecting pins 403, and an array of the plurality of connecting pins 403 is distributed on the top of the docking portion 401, wherein a heating resistor 404 is connected between two opposite connecting pins 403 in the middle, and an induction resistor 405 is provided on the outside of the heating resistor 404, and the induction resistor 405 is connected to other connecting pins 403 through connecting wires.

[0039] The number of connecting pins 403 is set to six, among which M2 pin and M5 pin are heating electrodes for connecting heating resistor 404. A certain voltage (usually 5V) needs to be applied between these two pins to provide enough current for heating resistor 404 to heat sensing resistor 405 to a suitable working temperature.

[0040] The M1 pin and the M3 pin as well as the M4 pin and the M6 ​​pin are short-circuited to serve as test electrodes. The two test electrodes are used to connect an external circuit to detect changes in the sensing resistor 405. When formaldehyde is adsorbed onto the surface of the sensitive material, the resistance of the sensing resistor 405 changes, thereby changing the voltage between the test electrodes. By detecting the change in the output voltage, the concentration of formaldehyde in the surrounding environment can be determined.

[0041] It should be noted that the sensing resistor 405 is usually made of metal oxide semiconductor materials (such as SnO2). When formaldehyde molecules exist in the surrounding environment, these gas molecules will be adsorbed onto the surface of the sensitive material, thereby changing the electrical properties of the sensitive material.

[0042] Specifically, a connecting portion 2 is provided on the top of the probe body 1, and the connecting portion 2 is used to connect to a control host.

[0043] An alarm unit 3 is provided on the top of the probe body 1. When the formaldehyde value exceeds a preset value, the alarm unit 3 will sound an alarm. The alarm unit 3 may be an audible and visual alarm.

[0044] In actual applications, the control host distributes multiple wires to realize electrical connection with each probe body 1. These probe bodies 1 are deployed in various areas of different environments according to specific environmental monitoring needs. After the installation and deployment of the probes are completed, the control host is started, and the control host sends a start signal to each probe through the wire to activate the semiconductor gas detection element therein, thereby performing formaldehyde gas detection.

[0045] Specifically, when harmful gases such as formaldehyde enter the mounting tube 402 inside the probe through the filter element 406, these gases will chemically react or physically adsorb with the induction resistor 405 on the docking portion 401. In this process, the resistance value of the induction resistor 405 will change accordingly. The higher the concentration of harmful gases such as formaldehyde, the stronger the reaction between the induction resistor 405 and the induction resistor 405, resulting in a more significant change in the resistance value of the induction resistor 405. It is worth noting that there is a proportional relationship between the change in resistance value and the concentration of the harmful gas.

[0046] The resistance change signal of the induction resistor 405 will be processed by the signal amplification circuit inside the probe body 1. The main function of this circuit is to amplify the weak resistance change signal and then convert it into a voltage signal proportional to the gas concentration. This voltage signal has high stability and accuracy, which is convenient for the control host to perform subsequent signal processing or display operations. Through this process, the control host can obtain the formaldehyde gas concentration information detected by each probe in real time, thereby realizing effective monitoring of the environmental formaldehyde concentration.

[0047] Embodiment 2 Although the first embodiment realizes effective monitoring of the formaldehyde concentration in the environment, when it is applied in a tunnel construction environment, due to the complexity of the environment in underground spaces such as tunnels, there is often a problem of poor ventilation, resulting in poor gas circulation, and formaldehyde is difficult to enter the interior of the installation tube 402 with the flow of air; at the same time, because the density of formaldehyde is greater than that of air, most of the formaldehyde is deposited in the area below the probe body 1, and the existing gas alarm generally lacks an effective wind guide structure design, making it difficult to effectively introduce the formaldehyde gas deposited in the lower layer into the detection unit of the alarm, thereby exacerbating the decrease in the accuracy of the alarm. In view of this, the following improvements are made on the basis of the first embodiment.

[0048] Reference Figures 1 to 11 As shown, a heat conducting plate 5 is provided inside the installation tube 402 , and the heat conducting plate 5 is in contact with the semiconductor gas detection element. The heat conducting plate 5 is provided with symmetrically distributed empty grooves 6 .

[0049] The drainage component 7 includes an insulating tube 701 arranged at the empty groove 6. The insulating tube 701 is fixedly connected to the mounting tube 402. A reciprocating component is provided inside the insulating tube 701. The reciprocating component is heated by the heat conducting plate 5 to realize the reciprocating movement of the reciprocating component inside the insulating tube 701, so that the formaldehyde gas deposited under the mounting tube 402 is sucked into the mounting tube 402.

[0050] Specifically, the reciprocating component includes a magnetic part 702, which is arranged inside the docking part 401, and its position corresponds to the position of the empty slot 6; the magnetic part 702 includes a permanent magnet or an electromagnet. When the magnetic part 702 is an electromagnet, the magnetic part 702 is electrically connected to the control host, and the control host controls the adsorption force of the magnetic part 702 on the soft magnetic part 703 by passing the current into the magnetic part 702.

[0051] The soft magnetic component 703 is arranged inside the heat-insulating cylinder 701 and is magnetically attracted to the magnetic component 702 . A piston plate 704 is provided at the bottom of the soft magnetic component 703 , and the piston plate 704 is slidably connected to the heat-insulating cylinder 701 .

[0052] The first elastic member 705 is disposed below the piston plate 704 and connected to the bottom of the heat insulation cylinder 701 .

[0053] Among them, the first elastic member 705 includes a compression spring. When the magnetic member 702 adsorbs the soft magnetic member 703, the first elastic member 705 is in a stretched state; when the soft magnetic member 703 loses its magnetism due to high temperature, the first elastic member 705 pulls the soft magnetic member 703 downward through the piston plate 704.

[0054] The one-way air inlet pipe 706 and the one-way air outlet pipe 707 are both arranged on the top of the heat insulation tube 701 , wherein the one-way air outlet pipe 707 is connected to the outer area of ​​the installation tube 402 .

[0055] Specifically, the Curie temperature of the magnetic component 702 is greater than the temperature generated when the heating resistor 404 is working, and the Curie temperature of the soft magnetic component 703 is less than the temperature generated when the heating resistor 404 is working.

[0056] Specifically, a support tube 8 is provided at the bottom of the heat-insulating tube 701 , and the support tube 8 is used to connect the inner area of ​​the heat-insulating tube 701 with the outer area of ​​the installation tube 402 .

[0057] The support tube 8 is used to introduce external air into the interior of the heat-insulating cylinder 701 to cool down the heated soft magnetic component 703 .

[0058] Specifically, the heights of the one-way air inlet pipe 706 and the one-way air outlet pipe 707 are not lower than the height of the inductive resistor 405 .

[0059] In the initial state, the magnetic component 702 adsorbs the soft magnetic component 703 , and at this time, the first elastic component 705 is in a stretched state, and the soft magnetic component 703 is located in the central area of ​​the empty slot 6 .

[0060] During use, after the control host starts the semiconductor gas detection element through the wire, the induction resistor 405 starts to heat up, and the heat energy generated by the induction resistor 405 acts on the soft magnetic part 703 through the heat conducting plate 5 to heat the soft magnetic part 703. When the heating temperature of the soft magnetic part 703 reaches the Curie point set by itself, the soft magnetic part 703 loses its ferromagnetism, and the magnetic part 702 cannot adsorb the soft magnetic part 703. At this time, under the influence of the elastic restoring force of the first elastic part 705, the first elastic part 705 drives the soft magnetic part 703 to move to the bottom of the insulation tube 701 through the piston plate 704. In this process, under the influence of the piston plate 704, a negative pressure is generated inside the insulation tube 701, and the insulation tube 701 sucks the external gas through the one-way air inlet pipe 706.

[0061] Reference Fig.10 As shown, when the insulation tube 701 performs suction operation, the gas at the bottom of the probe body 1 is pulled by negative pressure to flow toward the inside of the mounting tube 402. Since the height of the one-way air inlet pipe 706 and the one-way air outlet pipe 707 are higher than the height of the sensing resistor 405, during the gas flow, the gas will first contact and detect the sensing resistor 405, and then generate diversion and enter the insulation tube 701 through the one-way air inlet pipe 706.

[0062] When the soft magnetic component 703 moves to the bottom of the insulation tube 701, the piston plate 704 is located in the lower area of ​​the support tube 8. At this time, the gas drawn into the insulation tube 701 can be discharged from the support tube 8 to the installation tube 402. At the same time, the external gas can also enter the insulation tube 701 through the support tube 8 to cool the soft magnetic component 703.

[0063] When the temperature of the soft magnetic part 703 decreases, its own ferromagnetic properties gradually recover. After the ferromagnetic properties of the soft magnetic part 703 are recovered, under the influence of the magnetic attraction force of the magnetic part 702, the soft magnetic part 703 drives the piston plate 704 to move upward until the magnetic part 702 completes the adsorption of the soft magnetic part 703. At this time, the first elastic part 705 is in a stretched state, and the soft magnetic part 703 is located in the central area of ​​the empty slot 6.

[0064] Reference Fig.11 As shown, when the soft magnetic part 703 drives the piston plate 704 to move upward, the piston plate 704 squeezes the upper area of ​​the support tube 8, so that the gas inside the insulation tube 701 is discharged through the one-way air outlet pipe 707. When the gas is discharged from the one-way air outlet pipe 707, the discharged gas will not cause too much interference to the gas directly below the probe body 1, thereby avoiding excessive errors when the induction resistor 405 detects the gas subsequently sucked into the installation tube 402.

[0065] After the magnetic component 702 has finished adsorbing the soft magnetic component 703 , the heat conducting plate 5 continues to heat the soft magnetic component 703 so that the soft magnetic component 703 loses its ferromagnetism again, and the cycle repeats.

[0066] Embodiment 3 Although the above embodiment realizes active suction of the area below the probe body 1, due to the high dust content in the tunnel, during the process of sucking the formaldehyde gas, the dust will adhere to the filter 406. Over time, the dust will gradually block the filter 406, making it difficult for formaldehyde to effectively enter the installation tube 402. Even if it enters, its concentration is far lower than the normal value, which seriously weakens the detection accuracy of the alarm. In view of this, the following improvements are made on the basis of the second embodiment.

[0067] Reference Figures 1 to 11 As shown, the filter element 406 includes an annular plate 4061, which is arranged inside the installation cylinder 402, and the top of the filter element 406 is connected to the insulation cylinder 701 through a symmetrically arranged second elastic member 9.

[0068] A supporting ring corresponding to the annular plate 4061 is provided at the bottom of the installation cylinder 402 . The annular plate 4061 is located on the top of the supporting ring. The annular plate 4061 is slidably connected to the installation cylinder 402 .

[0069] The filter screen 4062 is disposed in the inner ring area of ​​the annular plate 4061 and is used to filter the gas entering the installation cylinder 402 .

[0070] During the operation of the reciprocating assembly, when the airflow passes through the filter screen 4062 and enters the interior of the installation cylinder 402, if the filter screen 4062 is partially blocked by dust, the airflow will experience periodic pressure fluctuations in the flow path entering the installation cylinder 402. This pressure fluctuation phenomenon is caused by the non-uniform flow of the airflow after being blocked, which in turn causes the impact force applied to the filter screen 4062 to also show periodic changes.

[0071] Due to the partial blockage of the filter 4062, the velocity distribution and direction of the fluid may change when passing through the filter 4062, inducing a series of complex fluid dynamics effects, including but not limited to vortex generation and turbulence intensification. These effects not only enhance the impact strength of the fluid on the filter 4062, but also promote the filter 4062 to drive the annular plate 4061 to produce a vertical vibration response, that is, up and down vibration.

[0072] When the fluid impact force acts on the filter 4062, the second elastic member 9 on the annular plate 4061 will undergo elastic deformation due to the pressure change, effectively absorbing and alleviating part of the impact energy. As the periodic fluctuation of the fluid impact force continues, the second elastic member 9 also undergoes periodic compression and recovery deformation. During this process, the second elastic member 9 drives the annular plate 4061 to continuously collide with the supporting ring at the bottom of the mounting tube 402, so as to realize automatic cleaning of the blocked area of ​​the filter 4062.

[0073] Embodiment 4 Although the above embodiment can realize automatic cleaning when the filter 4062 is partially blocked, in actual application, due to the high humidity in the tunnel, especially when the filter 406 installed deep in the tunnel is blocked, the adhesion strength between the dust and the filter 4062 will be enhanced due to the influence of humidity, and it is difficult to shake off the dust adhered to the filter 4062 by simple vibration. In view of this, the following improvements are made on the basis of the third embodiment.

[0074] Reference Figures 1 to 11 As shown, a connecting hose 10 is provided on the outside of the second elastic member 9, and the connecting hose 10 is connected to an annular groove arranged on the one-way air outlet pipe 707. An elastic membrane 11 is provided on the outside of the annular groove. When the elastic membrane 11 is fully expanded, the one-way air outlet pipe 707 is sealed.

[0075] It should be noted that the second elastic member 9 includes an elastic airbag, which can only perform reciprocating telescopic motion in the vertical direction.

[0076] Specifically, a connecting hose 12 is provided at the top of the heat-insulating cylinder 701 , and a pressure valve flap is provided at the connection between the connecting hose 12 and the heat-insulating cylinder 701 .

[0077] The inner circle of the annular plate 4061 is provided with array-distributed oblique holes 13, which are all connected to the connecting channel provided inside the annular plate 4061, and the connecting channel is connected to the connecting hose 12. The air outlet end of the oblique hole 13 faces the filter screen 4062.

[0078] When the filter screen 4062 is completely clogged with dust, when the piston plate 704 moves toward the bottom of the insulation cylinder 701, it is difficult to draw external gas into the installation cylinder 402 through the filter screen 4062. Therefore, when the piston plate 704 moves, the annular plate 4061 and the filter screen 4062 are affected by the negative pressure inside the insulation cylinder 701 and gradually move toward the top of the installation cylinder 402. During this process, the annular plate 4061 squeezes the second elastic member 9, so that the gas in the second elastic member 9 enters the annular groove through the connecting hose 10, forcing the elastic membrane 11 to expand completely, thereby realizing the sealing operation of the one-way air outlet pipe 707.

[0079] It should be noted that when the filter 4062 is not completely blocked by dust, external air can enter the interior of the mounting tube 402 through the filter 4062. Therefore, although the annular plate 4061 and the filter 4062 will move upward due to the negative pressure, the amount of movement is difficult to completely compress the second elastic member 9, that is, the elastic membrane 11 cannot fully expand.

[0080] When the piston plate 704 moves toward the bottom of the insulation cylinder 701, since the filter screen 4062 is completely blocked by dust, the gas entering the insulation cylinder 701 is only the original gas in the installation cylinder 402. As the piston plate 704 moves, it is difficult for the gas entering the insulation cylinder 701 to completely fill the insulation cylinder 701. Therefore, the area where the piston plate 704 stays is finally located above the support tube 8 (at this time, the first elastic member 705 cannot continue to pull down the piston plate 704), that is, the gas is confined to the top of the piston plate 704 and the insulation cylinder 701. As the heat conduction plate 5 continues to heat the gas between the piston plate 704 and the top of the insulation cylinder 701, the pressure inside the insulation cylinder 701 gradually increases. When the air pressure is greater than the pressure value of the pressure valve disc set at the connection between the connecting hose 12 and the insulation cylinder 701, the gas inside the insulation cylinder 701 is ejected through the connecting hose 12, and the gas impacts the filter screen 4062 through the inclined holes 13 on the inner circle of the annular plate 4061, thereby realizing the recoil of the blocked area of ​​the filter screen 4062, so that the external gas can pass through the filter screen 4062 and enter the interior of the installation cylinder 402.

[0081] When external air can enter the installation tube 402 through the filter 4062 , the second elastic member 9 gradually returns to normal due to the change in air pressure inside the installation tube 402 . At this time, the elastic membrane 11 retracts and releases the blocking operation on the one-way air outlet pipe 707 .

[0082] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A formaldehyde detection device based on multiple probes, characterized in that: include: A plurality of probe bodies (1), each of the probe bodies (1) being provided with a connecting portion (2) at the top, and the connecting portion (2) being used to be connected to a control host; A gas detection component (4) comprising a docking portion (401) arranged at the bottom of the probe body (1), wherein a semiconductor gas detection element is arranged in the middle of the docking portion (401) to detect the concentration of formaldehyde gas; A mounting tube (402) is provided on the outside of the semiconductor gas detection element, and a filter (406) is provided on the bottom of the mounting tube (402); formaldehyde enters the interior of the mounting tube (402) through the filter (406) at the bottom and contacts and reacts with the semiconductor gas detection element; A heat conducting plate (5), which is arranged inside the mounting tube (402) and in contact with the semiconductor gas detection element, and is provided with symmetrically distributed empty grooves (6); A drainage assembly (7) comprises an insulating tube (701) arranged at the empty groove (6), the insulating tube (701) being fixedly connected to the mounting tube (402), a reciprocating assembly being arranged inside the insulating tube (701), the reciprocating assembly being heated by the heat conducting plate (5) to achieve reciprocating movement of the reciprocating assembly inside the insulating tube (701), so that formaldehyde gas deposited below the mounting tube (402) is sucked into the mounting tube (402).

2. The formaldehyde detection device based on multiple probes according to claim 1, characterized in that: The reciprocating assembly comprises: A magnetic member (702) is arranged inside the docking portion (401), and its location corresponds to the location of the empty slot (6); A soft magnetic component (703) is arranged inside the heat-insulating cylinder (701) and is magnetically attracted to the magnetic component (702); a piston plate (704) is provided at the bottom of the soft magnetic component (703); and the piston plate (704) is slidably connected to the heat-insulating cylinder (701); A first elastic member (705) is disposed below the piston plate (704) and connected to the bottom of the heat insulation cylinder (701); The one-way air inlet pipe (706) and the one-way air outlet pipe (707) are both arranged on the top of the heat insulation cylinder (701), wherein the one-way air outlet pipe (707) is connected to the outer area of ​​the installation cylinder (402).

3. The formaldehyde detection device based on multiple probes according to claim 2 is characterized in that: A support tube (8) is provided at the bottom of the thermal insulation tube (701), and the support tube (8) is used to connect the internal area of ​​the thermal insulation tube (701) with the external area of ​​the installation tube (402).

4. The formaldehyde detection device based on multiple probes according to claim 3 is characterized in that: The semiconductor gas detection element comprises a plurality of connection pins (403), wherein the plurality of connection pins (403) are arranged in an array on the top of the docking portion (401), wherein a heating resistor (404) is connected between two opposing connection pins (403) located in the middle, and an induction resistor (405) is arranged outside the heating resistor (404), and the induction resistor (405) is connected to other connection pins (403) via a connecting wire.

5. The formaldehyde detection device based on multiple probes according to claim 4 is characterized in that: The heights at which the one-way air inlet pipe (706) and the one-way air outlet pipe (707) are located are not lower than the height at which the inductive resistor (405) is located.

6. The formaldehyde detection device based on multiple probes according to claim 5, characterized in that: The filter element (406) comprises: An annular plate (4061) is arranged inside the mounting cylinder (402), and the top of the annular plate is connected to the heat-insulating cylinder (701) via a symmetrically arranged second elastic member (9); The filter screen (4062) is arranged in the inner ring area of ​​the annular plate (4061) and is used to filter the gas entering the installation cylinder (402).

7. The formaldehyde detection device based on multiple probes according to claim 6, characterized in that: A connecting hose (10) is provided on the outside of the second elastic member (9), the connecting hose (10) being connected to an annular groove provided on the one-way air outlet pipe (707), an elastic membrane (11) being provided on the outside of the annular groove, and when the elastic membrane (11) is fully expanded, a blocking operation of the one-way air outlet pipe (707) is achieved.

8. The formaldehyde detection device based on multiple probes according to claim 7, characterized in that: A connecting hose (12) is provided at the top of the heat-insulating cylinder (701), and a pressure valve flap is provided at the connection between the connecting hose (12) and the heat-insulating cylinder (701); The inner ring of the annular plate (4061) is provided with inclined holes (13) distributed in an array, and the inclined holes (13) are all connected to a connecting channel provided inside the annular plate (4061), and the connecting channel is connected to a connecting hose (12).

9. The formaldehyde detection device based on multiple probes according to claim 4, characterized in that: The Curie temperature of the magnetic component (702) is greater than the temperature generated when the heating resistor (404) is working, and the Curie temperature of the soft magnetic component (703) is less than the temperature generated when the heating resistor (404) is working.

10. The formaldehyde detection device based on multiple probes according to claim 1, characterized in that: An alarm unit (3) is provided on the top of the probe body (1); when the formaldehyde value exceeds a preset value, the alarm unit (3) sounds an alarm.

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