Gas sampling probe

Abstract

The utility model discloses a kind of gas sampling probe, including shell, explosion-proof heating device and the probe body being installed in shell;Filtering chamber is equipped in probe body, filter is equipped in filtering chamber;Probe body is equipped with with filtering chamber intercommunication's sample gas import and sample gas export;Explosion-proof heating device includes heater being installed in shell and explosion-proof terminal box being installed in shell outside;Explosion-proof terminal box includes explosion-proof box body and temperature control unit being installed in explosion-proof box body and with heater electric connection;The cold end of heater extends out the shell, and is connected with explosion-proof box body by explosion-proof mechanism.The utility model makes temperature control unit be set to the outside of probe, only needs to carry out explosion-proof to the line and relevant components that exist explosion risk, and explosion-proof of entire probe is not needed, explosion-proof shell is not needed to be set, so the probe compared with prior art, not only save cost, and can be conveniently installed and maintained to probe.

Description

Technical Field

[0001] This utility model relates to the field of gas sampling technology, specifically to a gas sampling probe. Background Technology

[0002] A gas sampler is an instrument used to collect gas samples from the atmospheric or workplace environment, primarily serving fields such as industrial process monitoring, environmental monitoring, and occupational health protection. Types of samplers include handheld single-channel samplers, explosion-proof samplers, and dual-channel systems. Explosion-proof gas samplers are mainly used in chemical, petroleum, metallurgical, and environmental protection settings, typically requiring the sampling and analysis of high-temperature, corrosive, or dust-laden gases. However, due to the complex sampling environment, the sample gas may contain dust, moisture, or corrosive components, easily leading to clogging, condensation, or corrosion of the sampling probe, thus affecting sampling accuracy and equipment lifespan.

[0003] Traditional sampling probes typically employ simple filter structures, but over long-term use, these filters are prone to clogging due to dust accumulation, requiring frequent maintenance or replacement. Furthermore, in low-temperature or high-humidity environments, sample gases may condense in the sampling pipeline, leading to measurement distortion. To address this issue, some sampling probes are equipped with heating functions to prevent gas condensation. For example, utility model patent CN208860648U discloses a gas sampling probe, specifically comprising a sampling tube and a sample gas processing pipeline. The outer wall of this sample gas processing pipeline is covered with an electric heating layer, which is then covered with a sealing layer, an asbestos layer, and finally an explosion-proof shell. The electric heating layer is used to heat the sample gas. A temperature control switch is installed on the electric heating layer to control its on / off state. The electric heating layer also includes a temperature sensor to sense its temperature. A wiring outlet is provided on the explosion-proof shell, through which a wire passes through the asbestos layer and the sealing layer, connecting to the temperature control switch and the temperature sensor, respectively. The outlet is sealed with an explosion-proof gland to secure and protect the wire. This technology places the heating element inside the explosion-proof housing of the probe, providing explosion protection. However, this type of probe is inconvenient to install and maintain, and is also costly.

[0004] Therefore, there is an urgent need for a gas sampling probe that is highly efficient in heating, explosion-proof and safe, and easy to maintain, in order to meet the sampling needs in complex industrial environments. Utility Model Content

[0005] The purpose of this invention is to provide a gas sampling probe that solves the problems of inconvenient installation and maintenance, and high cost of existing gas sampling probes.

[0006] To solve the above-mentioned technical problems, this utility model provides a gas sampling probe, including a housing, an explosion-proof heating device, and a probe body installed inside the housing;

[0007] The probe body contains a filter chamber, which contains a filter; the probe body has a sample gas inlet and a sample gas outlet that are connected to the filter chamber; the sample gas enters the filter chamber through the sample gas inlet, is filtered by the filter, and is then delivered to the downstream equipment for connection through the sample gas outlet.

[0008] The explosion-proof heating device includes a heater installed inside the housing and an explosion-proof junction box installed outside the housing; the explosion-proof junction box includes an explosion-proof enclosure and a temperature control unit installed inside the explosion-proof enclosure, and the temperature control unit is electrically connected to the heater; the cold end of the heater extends outside the housing and is connected to the explosion-proof enclosure through an explosion-proof mechanism.

[0009] Furthermore, the explosion-proof mechanism includes a threaded connector that is fixedly connected to the cold end of the heater, and the threaded connector and the explosion-proof housing cooperate to form a threaded explosion-proof mating surface.

[0010] Furthermore, the hot end of the heater includes a heat-conducting cover, a first temperature sensor disposed within the heat-conducting cover, and a heating wire uniformly surrounding the first temperature sensor; the temperature control unit includes a first temperature controller and a first relay; the control output terminal of the first temperature controller is electrically connected to the control input terminal of the first relay, the first temperature sensor is electrically connected to the input terminal of the first temperature controller, and the heating wire is electrically connected to the output terminal of the first relay.

[0011] Furthermore, the gas sampling probe also includes a secondary temperature protection circuit; the secondary temperature protection circuit includes a second temperature sensor installed inside the housing and a second temperature controller and a second relay located outside the housing. The temperature measurement input terminal of the second temperature controller is electrically connected to the second temperature sensor, the control output terminal of the second temperature controller is electrically connected to the control input terminal of the second relay, and the output terminal of the second relay is connected in series with the first relay and then electrically connected to the heating wire.

[0012] Furthermore, a heating block is also fitted on the outside of the heater to conduct the heat generated by the heater to the probe body.

[0013] Furthermore, the filter chamber includes a detachably connected probe base and probe cover; the filter chamber is a straight-through cavity located within the probe base; the filter has a cup-shaped structure, and the open end of the filter is detachably connected to the probe cover; the sample gas outlet is located on the probe cover.

[0014] Furthermore, a first purge gas interface is provided on the outer side of the probe body. The first purge gas interface is connected to the interior of the filter through a first purge gas channel that penetrates the side wall of the probe body. The purge gas flow entering the interior of the filter through the first purge gas interface and the first purge gas channel acts on the inner side wall of the filter.

[0015] Furthermore, a second purge gas interface is provided on the outer side of the probe body. The second purge gas interface is connected to the interior of the filter chamber through a second purge gas channel that penetrates the side wall of the probe body. The purge gas flow entering the interior of the filter chamber through the second purge gas interface and the second purge gas channel acts on the outer wall of the filter.

[0016] Furthermore, the probe cover is detachably pressed onto the end of the probe seat away from the sample gas inlet by a pressing device; the pressing device includes a bracket and a pressing rod. The bracket is parallel to and spaced apart from the probe cover. Both ends of the bracket are connected to the probe seat by a support rod. One end of the pressing rod passes longitudinally through the middle of the bracket and is rotatably connected to the probe cover. The other end of the pressing rod is provided with an operating handle.

[0017] Furthermore, the housing includes a protective shell and an insulation layer disposed inside the protective shell.

[0018] The beneficial effects of this utility model are as follows: by separating the heater from the explosion-proof junction box, the temperature control unit is placed inside the explosion-proof box outside the probe. At the same time, by optimizing the arrangement of the purely mechanical structural parts in the probe that have no explosion risk, it is only necessary to make the circuits and related components with explosion risk explosion-proof, without having to make the entire gas sampling probe explosion-proof or install an explosion-proof shell. Therefore, compared with the prior art, this gas sampling probe not only saves costs, but also facilitates the installation and maintenance of the probe. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, use the same reference numerals to denote the same or similar parts. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0020] Figure 1 This is a schematic diagram of the overall structure of the high-temperature explosion-proof sampling probe of this utility model;

[0021] Figure 2 This is a schematic diagram of the heater structure of this utility model;

[0022] Figure 3 This is a schematic diagram of the probe temperature control circuit of this utility model;

[0023] The components include: 1. Probe base; 11. Filter; 12. First purge gas interface; 13. Second purge gas interface; 14. Flange; 15. Mounting plate; 2. Probe cover; 21. Sample gas outlet; 22. Sealing ring; 3. Pressure rod; 31. Bracket; 32. Support rod; 33. Protrusion; 34. Operating handle; 4. Heater; 41. Heating wire; 42. First temperature sensor; 43. Heat-conducting cover; 44. Cold end; 45. Locking nut; 46. Threaded connector; 47. Sealing cavity; 48. Cable; 5. Heating block; 6. Second temperature sensor; 7. Explosion-proof junction box; 71. Terminal block; 72. First relay; 73. First temperature controller; 8. Protective shell; 81. Insulation layer; 9. Sampling tube. Detailed Implementation

[0024] like Figure 1 The gas sampling probe shown includes a housing, an explosion-proof heating device, and a probe body installed inside the housing. The probe body is made of metal, but considering that the sample gas may have characteristics such as high temperature and corrosiveness in actual applications, the probe body can be made of stainless steel.

[0025] The probe body contains a filter chamber with a filter 11. The probe body has a sample gas inlet and a sample gas outlet 21 connected to the filter chamber. Sample gas enters the filter chamber through the sample gas inlet, is filtered by the filter 11, and is then delivered to the next-stage equipment via the sample gas outlet 21. The filter 11 filters dust and other substances from the collected sample gas. The specific filter layer of the filter 11 can be configured according to the sample gas and the impurities to be filtered out. To facilitate the collection of sample gas from specific locations, a sampling tube can be added to the sample gas inlet. The shape and length of the sampling tube can be configured according to the sampling environment; for example, a longer sampling tube is required to reach deeper into the sample sampling point to meet sampling needs under specific conditions. Valves can be optionally equipped on the sample gas inlet and sample gas outlet 21. The next-stage equipment connected to the sample gas outlet 21 should also be equipped with a pump to provide power for the collected sample gas.

[0026] The explosion-proof heating device includes a heater 4 installed inside the housing and an explosion-proof junction box 7 installed outside the housing. The explosion-proof junction box 7 can be installed on a mounting plate 15 extending outward from the probe base 11. The explosion-proof junction box 7 includes an explosion-proof enclosure and a temperature control unit installed inside the explosion-proof enclosure. The temperature control unit is electrically connected to the heater 4. The cold end of the heater 4 extends out of the housing and is connected to the explosion-proof enclosure via an explosion-proof mechanism. Through the separate design of the heater 4 and the explosion-proof junction box 7, the temperature control unit is located inside the explosion-proof enclosure outside the probe. Only the circuits and related components with explosion risks need to be explosion-proofed, rather than the entire gas sampling probe. Therefore, compared with existing technologies, this gas sampling probe not only saves costs but also facilitates the installation and maintenance of the probe.

[0027] According to one embodiment of this application, the explosion-proof mechanism includes a threaded connector 46 fixedly connected to the cold end 44 of the heater. The threaded connector 46 and the explosion-proof housing cooperate to form a threaded explosion-proof mating surface. The cold end 44 of the heater and the threaded connector 46 can be fixed together by welding. The outer side of the threaded connector 46 is provided with an external thread, and the wiring port of the explosion-proof housing is provided with an internal thread that mates with the external thread. The external thread of the threaded connector 46 and the internal thread of the explosion-proof housing cooperate to form a threaded explosion-proof mating surface. This embodiment ensures that the threaded mating surface between the cold end of the heater 4 and the threaded connector 46 meets the explosion-proof standard requirements, thus forming an explosion-proof structure between the cold end of the heater 4 and the explosion-proof housing. It can meet the requirements for gas explosion protection while also meeting the requirements for dust explosion protection, expanding the application scenarios in explosive dust environments. For easier installation and maintenance, a locking nut 45 can be added to the outer side of the threaded connector 46. When the threaded connector 46 is about to be tightened, the locking nut 45 can be tightened to lock it, ensuring that the hot end of the heater faces upwards, so as to facilitate the installation of the hot end of the heater in the probe body. The threaded connector 46 forms a sealing cavity 47 inside. After the cable 48 connecting the heater is sealed in the sealing cavity 47, it is electrically connected to the temperature control unit inside the explosion-proof box.

[0028] The hot end of the heater is the main working part of the heater, which converts electrical energy into heat energy to heat the object or medium it comes into contact with; while the cold end of the heater does not directly participate in the heating process. It mainly serves to connect and fix the heater and to stably transmit electrical energy to the hot end.

[0029] According to one embodiment of this application, the hot end of the heater 4 includes a heat-conducting cover 43, a first temperature sensor 42 disposed within the heat-conducting cover 43, and a heating wire 41 uniformly surrounding the first temperature sensor 42. The first temperature sensor 42 is electrically connected to the input terminal of a temperature control unit, and the heating wire 41 is electrically connected to the output terminal of the temperature control unit. The heating wire 41 is arranged around the first temperature sensor 42 to further optimize heating uniformity, avoid local overheating, improve temperature detection accuracy, and reduce measurement errors. The first temperature sensor 42 may be a thermocouple; the heating wire 41 may be an electrically heated metal wire.

[0030] To ensure heating capacity and efficiency, a higher-power heater 4 should be selected, preferably an 800W heater 4. For ease of application, heater 4 should be powered by 220V. By setting the heating control temperature of the temperature controller in the explosion-proof junction box, the probe heating temperature can correspond to temperature groups T1 to T6 in explosion-proof locations, expanding the probe heating temperature range and improving the product's applicability.

[0031] According to one embodiment of this application, the temperature control unit includes a first temperature controller 73 and a first relay 72 (which may be a solid-state relay). The control output terminal of the first temperature controller 73 is electrically connected to the control input terminal of the first relay 72, the first temperature sensor 42 is electrically connected to the input terminal of the first temperature controller 73, and the heating wire 41 is electrically connected to the output terminal of the first relay 72. The first temperature controller 73 in the explosion-proof junction box 7 detects the temperature signal fed back by the first temperature sensor 42 in the heater 4. When the detected temperature is lower than the set value, it controls the first relay 72 to supply power to the heater 4, and the heater 4 starts heating. When the temperature of the first temperature sensor 42 approaches the set value, the first temperature controller 73 performs PID adjustment to control the first temperature sensor 42 to stabilize around the set value. When the temperature of the first temperature sensor 42 is too high and reaches the alarm set value, the first temperature controller 73 controls the solid-state first relay 72 to cut off the power to the heater 4, stopping the probe heating.

[0032] According to one embodiment of this application, to ensure safer use of the probe, the gas sampling probe is further equipped with a secondary temperature protection circuit. The secondary temperature protection circuit includes a second temperature sensor 6 installed inside the housing and a second temperature controller and a second relay (which can be a solid-state relay) located outside the housing. The temperature input terminal of the second temperature controller is electrically connected to the second temperature sensor 6, and the control output terminal of the second temperature controller is electrically connected to the control input terminal of the second relay. The output terminal of the second relay is connected in series with the first relay 72 and then electrically connected to the heating wire 41. The second temperature sensor 6 can be an explosion-proof platinum resistance thermometer. The second temperature controller and the second relay form a secondary temperature protection circuit (external temperature control circuit). During operation, the temperature signal fed back by the second temperature sensor 6 is sent to the second temperature controller, which controls one power input (live wire) of the heater 4 through a second relay. Only when the temperature of the second temperature sensor 6 does not exceed the set value can the heater 4 of the probe be controlled by the probe temperature control circuit in the explosion-proof junction box 7, thus providing secondary protection to prevent overheating risk due to independent temperature control failure.

[0033] According to one embodiment of this application, a heating block 5 is also fitted on the outside of the heater 4 to conduct the heat generated by the heater 4 to the probe body. The heating block 5 increases the heat conduction area, ensuring uniform heating of the probe body and preventing sample gas condensation. Considering the efficiency of heat conduction, the heating block 5 can be made of aluminum, provided the heating temperature does not exceed 450°C.

[0034] According to one embodiment of this application, the filter chamber includes a detachably connected probe base 1 and probe cover 2; the filter chamber is a straight-through cavity disposed within the probe base 1; the filter 11 has a cup-shaped structure, and the open end of the filter 11 is detachably connected to the probe cover 2; the sample gas outlet 21 is disposed on the probe cover 2. The straight-through cavity design reduces gas flow resistance and improves sampling efficiency; the detachable connection between the filter 11 and the probe cover 2 facilitates maintenance and replacement. To ensure the sealing between the probe base 1 and the probe cover 2, a sealing ring 22 is used to seal between them, preventing external gas intrusion during probe sampling and thus avoiding sample distortion. Preferably, when the probe heating temperature is below 300°C, a rubber sealing ring 22 can be used; when the probe heating temperature is above 300°C, a graphite sealing ring 22 can be used. The number of sealing rings 22 can be set as needed according to the contact surface structure between the probe base 1 and the probe cover 2.

[0035] The probe holder 1 is provided with a flange 14 at one end connected to the sampling tube, and the probe is installed at the sample sampling point through the flange 14.

[0036] According to one embodiment of this application, a first purge gas interface 12 is provided on the outer side of the probe body. The first purge gas interface 12 is connected to the interior of the filter 11 through a first purge gas channel penetrating the side wall of the probe body. The purge gas flow entering the interior of the filter 11 through the first purge gas interface 12 and the first purge gas channel acts on the inner side wall of the filter 11. After the filter 11 filters the sample gas for a certain period of time, the sampling flow rate will be affected by the accumulation of dust and other substances. Therefore, this embodiment achieves "internal blowing" by setting the first purge gas interface 12 and the first purge gas channel acting on the inner side wall of the filter 11. During cleaning, the first purge gas interface 12 is connected to a compressed gas source, and a high-speed airflow is used to purge the interior of the filter 11, reducing the frequency of product maintenance. At this time, the flow direction of the purge gas is opposite to the flow direction of the sample gas.

[0037] According to one embodiment of this application, a second purge gas interface 13 is provided on the outer side of the probe body. The second purge gas interface 13 is connected to the interior of the filter chamber through a second purge gas channel penetrating the side wall of the probe body. The purge gas flow entering the interior of the filter chamber through the second purge gas interface 13 and the second purge gas channel acts on the outer wall of the filter 11. When periodic cleaning is required, the second purge gas interface 13 is connected to a compressed gas source, and a high-speed airflow can be used to blow dust off the probe, effectively preventing the filter 11 from clogging and reducing the frequency of product maintenance. At this time, the flow direction of the purge gas is the same as the flow direction of the sample gas.

[0038] According to one embodiment of this application, the probe cover 2 is detachably press-fitted onto the end of the probe seat 1 away from the sample gas inlet using a pressing device. The pressing device includes a bracket 31 and a pressing rod 3. The bracket 31 is parallel to and spaced apart from the probe cover 2. Both ends of the bracket 31 are connected to the probe seat 1 via a support rod 32. One end of the pressing rod 3 longitudinally passes through the middle of the bracket 31 and is rotatably connected to the probe cover 2. The other end of the pressing rod 3 is provided with an operating handle 34. This embodiment enables quick assembly and disassembly of the probe cover 2 by using a pressing device, facilitating installation and maintenance.

[0039] According to one embodiment of this application, the housing includes a protective shell 8 and a thermal insulation layer 81 disposed inside the protective shell 8. By providing the protective shell 8 and the thermal insulation layer 81, not only can a better protective environment be provided for the sampling probe, but it is also beneficial to maintain heating efficiency.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A gas sampling probe, characterized in that, It includes a housing, an explosion-proof heating device, and a probe body installed inside the housing; The probe body is equipped with a filter chamber, and the filter chamber is equipped with a filter; the probe body is equipped with a sample gas inlet and a sample gas outlet that communicate with the filter chamber; the sample gas enters the filter chamber through the sample gas inlet, is filtered by the filter, and is then delivered to the downstream equipment for connection through the sample gas outlet; The explosion-proof heating device includes a heater installed inside the housing and an explosion-proof junction box installed outside the housing; the explosion-proof junction box includes an explosion-proof enclosure and a temperature control unit installed inside the explosion-proof enclosure, the temperature control unit being electrically connected to the heater; the cold end of the heater extends outside the housing and is connected to the explosion-proof enclosure via an explosion-proof mechanism.

2. The gas sampling probe according to claim 1, characterized in that, The explosion-proof mechanism includes a threaded connector that is fixedly connected to the cold end of the heater, and the threaded connector and the explosion-proof housing cooperate to form a threaded explosion-proof mating surface.

3. The gas sampling probe according to claim 1 or 2, characterized in that, The hot end of the heater includes a heat-conducting cover, a first temperature sensor disposed inside the heat-conducting cover, and heating wires uniformly surrounding the first temperature sensor; the temperature control unit includes a first temperature controller and a first relay; the control output terminal of the first temperature controller is electrically connected to the control input terminal of the first relay, the first temperature sensor is electrically connected to the input terminal of the first temperature controller, and the heating wires are electrically connected to the output terminal of the first relay.

4. The gas sampling probe according to claim 3, characterized in that, The gas sampling probe also includes a secondary temperature protection circuit; the secondary temperature protection circuit includes a second temperature sensor installed inside the housing and a second temperature controller and a second relay disposed outside the housing. The temperature measurement input terminal of the second temperature controller is electrically connected to the second temperature sensor, the control output terminal of the second temperature controller is electrically connected to the control input terminal of the second relay, and the output terminal of the second relay is connected in series with the first relay and then electrically connected to the heating wire.

5. The gas sampling probe according to claim 1, characterized in that, The heater is also fitted with a heating block on its outside to conduct the heat generated by the heater to the probe body.

6. The gas sampling probe according to claim 1, characterized in that, The filter chamber includes a detachably connected probe base and a probe cover; the filter chamber is a straight-through cavity disposed within the probe base; the filter has a cup-shaped structure, and the open end of the filter is detachably connected to the probe cover; the sample gas outlet is disposed on the probe cover.

7. The gas sampling probe according to claim 6, characterized in that, The probe body is provided with a first purge gas interface on its outer side. The first purge gas interface is connected to the inside of the filter through a first purge gas channel that penetrates the side wall of the probe body. The purge gas flow entering the inside of the filter through the first purge gas interface and the first purge gas channel acts on the inner side wall of the filter.

8. The gas sampling probe according to claim 6 or 7, characterized in that, The probe body has a second purge gas interface on its outer side. The second purge gas interface is connected to the interior of the filter chamber through a second purge gas channel that penetrates the side wall of the probe body. The purge gas flow entering the interior of the filter chamber through the second purge gas interface and the second purge gas channel acts on the outer wall of the filter.

9. The gas sampling probe according to claim 6, characterized in that, The probe cover is detachably pressed onto the end of the probe seat away from the sample gas inlet by a pressing device. The pressing device includes a bracket and a pressing rod. The bracket is parallel to and spaced apart from the probe cover. Both ends of the bracket are connected to the probe seat by a support rod. One end of the pressing rod passes through the middle of the bracket longitudinally and is rotatably connected to the probe cover. The other end of the pressing rod is provided with an operating handle.

10. The gas sampling probe according to claim 1, characterized in that, The housing includes a protective shell and an insulation layer disposed inside the protective shell.

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