Explosion-proof electric cabinet

Abstract

This invention discloses an explosion-proof electrical cabinet for use in the hazardous area of ​​a flammable refrigerant air conditioning thermal balance laboratory. It includes: a sealed cabinet located within the hazardous area of ​​the thermal balance laboratory, creating a positive pressure environment; a gas source located outside the hazardous area, which outputs compressed air at a first specified temperature into the sealed cabinet; and / or maintains a specified gas leakage rate within the sealed cabinet; and a temperature control component located within the sealed cabinet, the input power of which is measured by a power meter, and the cooling capacity is measured and calculated using a flow meter and a temperature sensor. This invention configures the operating states of the gas source, temperature control component, and valves based on the relationship between the heat measurement error caused by compressed air and the gas leakage rate within the cabinet. While ensuring safety, it avoids the impact of heat dissipation from electrical components on the room's air conditioning thermal balance experiment.

Description

Technical Field

[0001] This invention relates to the field of air conditioning, and in particular to an explosion-proof electrical cabinet for use in the hazardous area of ​​a heat balance laboratory for flammable refrigerants. Background Technology

[0002] In the residential and commercial air conditioning sector, hydrocarbon refrigerant R290 has gradually become the mainstream alternative to Freon due to its technological advantages and environmentally friendly characteristics. Because R290 is a flammable gas, leaks can easily cause fires or even explosions; therefore, laboratories testing R290 air conditioners need to consider specific safety measures.

[0003] Within the laboratory, operations involving air conditioning assembly, refrigerant charging, refrigerant evacuation, and refrigerant discharge are required. Furthermore, according to the latest IEC standards, the maximum amount of R290 that can be added is approaching 1 kg. Additionally, the laboratory testing environment is a constant temperature and humidity environment, typically ranging from -40°C to 70°C. Therefore, maintaining a large exchange of fresh air with the outside air during testing is not suitable to ensure the laboratory testing environment remains a non-hazardous area. Consequently, the laboratory testing area is generally classified as Hazard Zone I or Hazard Zone II.

[0004] Hazard Zone 2 refers to an environment where explosive gas mixtures are unlikely to occur during normal operation, or if they do occur, they are only present for a short period. The classification of hazard zones is determined based on the frequency and duration of the presence of explosive gas mixtures. Hazard Zone 2 is typically found in specific locations, such as unenclosed areas in oil and petrochemical plants, where hazardous gases are virtually nonexistent, and even if they do occur, their presence is brief, usually not exceeding 10 hours per year.

[0005] In existing technologies, R290 air conditioning enthalpy difference laboratories typically employ the following methods:

[0006] 1. All electrical components in the laboratory are explosion-proof, such as intrinsically safe and flameproof types.

[0007] 2. All metal surfaces in the laboratory must be fully grounded.

[0008] 3. The laboratory is equipped with several combustible gas detectors and audible and visual alarms.

[0009] 4. Maximum temperature limits must be imposed on all hot surfaces in the laboratory.

[0010] 5. The laboratory is equipped with an exhaust system. When the combustible gas detector is activated, the exhaust system will be started to quickly exchange air with the outside environment.

[0011] However, the R290 air conditioning heat balance laboratory differs from the enthalpy difference chamber. Based on the measurement principle, it is necessary to measure the total power of all electrical components within the heat balance laboratory. Because the total power needs to be measured, all heat-generating components downstream of the power meter must be placed within the laboratory chamber. These components include:

[0012] 1. Power equipment: fans, electric heating, electric humidification, etc.

[0013] 2. Electrical components: air switches, frequency converters, thyristors, etc.

[0014] Explosion-proof fans and explosion-proof electric heaters are relatively easy to obtain. However, explosion-proof electrical components are either too large (e.g., circuit breakers) or very difficult to obtain (e.g., silicon controlled rectifiers).

[0015] If explosion-proof electrical cabinets are used to isolate these electrical components from the interior, it is necessary to consider not only the cooling of the components inside the cabinet but also the measurement of their heat dissipation. A common technique is to allow ventilation between the explosion-proof cabinet and the outside environment. This maintains positive pressure inside the cabinet and helps dissipate heat. However, this method of maintaining ventilation between the cabinet and the outside is not feasible, as it would lead to inaccurate heat dissipation measurements and distort the laboratory results of room air conditioning thermal balance measurements. Summary of the Invention

[0016] The summary of this invention introduces a series of simplified concepts, all of which are simplifications of existing technologies in the field, and will be further explained in detail in the detailed description section. This summary is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0017] The technical problem to be solved by the present invention is to provide an explosion-proof electrical cabinet that, under the premise of ensuring safety, avoids the impact of heat dissipation of electrical components inside the explosion-proof electrical cabinet on the thermal balance test results of room air conditioning.

[0018] To solve the above-mentioned technical problems, the present invention provides an explosion-proof electrical cabinet for use in the hazardous area of ​​a flammable refrigerant air conditioning heat balance laboratory, comprising:

[0019] Sealed cabinet 1 is located in the hazardous area of ​​the thermal balance laboratory, and a positive pressure environment is formed inside it.

[0020] Gas source 2, located outside the hazardous area of ​​the laboratory, outputs compressed air at a first specified temperature into the sealed enclosure 1; and / or maintains a specified gas leakage rate in the sealed enclosure 1.

[0021] The temperature control component is arranged inside the sealed cabinet 1. The input power of the temperature control component is measured by a power meter, and the cooling capacity is measured and calculated by a flow meter and a temperature sensor.

[0022] Preferably, the explosion-proof electrical cabinet is further improved by including:

[0023] Pressure relief valve 3 is installed on the pipeline connecting the sealed cabinet 1 to the hazardous area inside the laboratory.

[0024] Differential pressure switch 13 is used to detect the differential pressure between the sealed cabinet 1 and the laboratory hazardous area. If the differential pressure is less than the first specified differential pressure, the power supply is disconnected. If the differential pressure is greater than the second specified differential pressure, the power supply to the cabinet and the gas supply are cut off, and an alarm is issued. If the differential pressure is greater than the third specified differential pressure, the pressure relief valve 3 is opened.

[0025] Preferably, in a further improvement of the explosion-proof electrical cabinet, the compressed air output from the air source 2 is adjusted to a specified pressure by the pressure reducing valve 4, and then enters the heat exchanger 5 to fully exchange heat with the air in the hazardous area of ​​the laboratory's outer chamber before entering the sealed cabinet 1 through the first regulating valve 6.

[0026] The first regulating valve 6 is used to regulate the amount of gas leakage from the sealed cabinet 1;

[0027] The bypass valve 7 is connected in parallel with the first regulating valve 6 and is opened only when the electrical cabinet needs ventilation or purging.

[0028] Preferably, the explosion-proof electrical cabinet is further improved so that the air source 2 outputs compressed air at constant pressure.

[0029] Preferably, the explosion-proof electrical cabinet is further improved such that the power supply is disconnected when the positive pressure inside the sealed cabinet 1 is less than the positive pressure extreme value.

[0030] Preferably, the explosion-proof electrical cabinet is further improved by determining the allowable heat measurement error caused by compressed air based on the lower limit of the air conditioning cooling or heating capacity measured in the heat balance laboratory.

[0031] The error in heat measurement caused by compressed air = gas leakage * 1.2 / 3600 * 1.005 * (compressed air temperature - laboratory hazardous area temperature);

[0032] The gas leakage rate is calculated and then adjusted by the first regulating valve 6 to achieve the desired gas leakage rate.

[0033] Preferably, in a further improvement to the explosion-proof electrical cabinet, the temperature regulation component includes:

[0034] Fan 8, which is located in an explosion-proof electrical cabinet, is used to accelerate the heat exchange of the indirect cooling coil 9;

[0035] Temperature sensor 10 is located inside an explosion-proof electrical cabinet;

[0036] And, electric heating 11 and / or second regulating valve 12;

[0037] Electric heater 11 is arranged inside the explosion-proof electrical cabinet to control the temperature inside the explosion-proof electrical cabinet.

[0038] The second regulating valve 12 is located at the coolant inlet of the intercooling coil 9 and is used to regulate the cooling volume in the electrical cabinet.

[0039] Preferably, in a further improvement to the explosion-proof electrical cabinet, the temperature regulation component includes:

[0040] The coolant in the cooling coil 9 should be from the same source as the cooling coil 14 in the air conditioning cabinet of the hazardous area of ​​the laboratory. The coolant supply pipe forms a branch in the hazardous area of ​​the laboratory, and the return pipe forms a confluence in the hazardous area of ​​the laboratory.

[0041] Preferably, the explosion-proof electrical cabinet is further improved such that when the temperature of the sealed cabinet 1 exceeds a second specified temperature, the power supply is cut off.

[0042] Preferably, the explosion-proof electrical cabinet is further improved by performing multiple air exchanges and / or purging for a specified duration before powering on. During purging, the bypass valve 7 and the pressure relief valve 3 need to be opened.

[0043] Preferably, the explosion-proof electrical cabinet is further improved by having good sealing performance. When the differential pressure between the inside and outside of the explosion-proof electrical cabinet is 200Pa, the leakage is about 0.5 to 3 times the internal volume of the electrical cabinet per hour.

[0044] Preferably, in a further improvement of the explosion-proof electrical cabinet, the pressure relief valve 3 can be a pneumatic valve, an explosion-proof electric valve, or a mechanical valve that can be repeatedly opened, or it can be moved to a safe area outside the laboratory.

[0045] Preferably, in a further improvement to the explosion-proof electrical cabinet, the bypass valve 7 can be a pneumatic valve, an explosion-proof electric valve, or can be moved to a safe area outside the laboratory.

[0046] Preferably, in a further improvement to the explosion-proof electrical cabinet, the differential pressure switch 13 should be able to operate in hazardous Zone I or Zone II.

[0047] This invention configures the working status of the air source, temperature control components, and valves based on the relationship between the heat measurement error caused by compressed air and the amount of gas leakage inside the cabinet. Under the premise of ensuring safety, it can avoid the impact of heat dissipation of electrical components on the room air conditioning thermal balance experiment. Attached Figure Description

[0048] The accompanying drawings are intended to illustrate the general characteristics of the methods, structures, and / or materials used in specific exemplary embodiments of the invention, supplementing the description in the specification. However, the drawings are schematic diagrams not drawn to scale and may not accurately reflect the precise structural or performance characteristics of any of the given embodiments. The drawings should not be construed as limiting or restricting the range of numerical values ​​or properties covered by exemplary embodiments of the invention. The invention will now be described in further detail with reference to the accompanying drawings and specific embodiments:

[0049] Figure 1 This is a schematic diagram of the structure of the present invention.

[0050] Explanation of reference numerals in the attached figures:

[0051] Sealed cabinet 1

[0052] Gas source 2

[0053] Pressure relief valve 3

[0054] Pressure reducing valve 4

[0055] Heat exchanger 5

[0056] First regulating valve 6

[0057] Bypass valve 7

[0058] Fan 8

[0059] Indirect cooling coil 9

[0060] Temperature sensor 10

[0061] Electric heating 11

[0062] Second regulating valve 12

[0063] Differential pressure switch 13

[0064] 14. Cold coils in the air conditioning cabinet. Detailed Implementation

[0065] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can fully understand other advantages and technical effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through different specific embodiments, and various details in this specification can also be applied based on different viewpoints, with various modifications or changes made without departing from the overall design concept of the invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. The following exemplary embodiments of the present invention can be implemented in many different forms and should not be construed as being limited to the specific embodiments set forth herein. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete, and to fully convey the technical solutions of these exemplary embodiments to those skilled in the art. It should be understood that when an element is referred to as "connected" or "combined" to another element, the element can be directly connected or combined to the other element, or there may be intermediate elements. The difference is that when an element is referred to as "directly connected" or "directly combined" to another element, there are no intermediate elements. Throughout the drawings, the same reference numerals always denote the same elements.

[0066] First embodiment;

[0067] This invention provides an explosion-proof electrical cabinet for a hazardous area in a laboratory testing thermal balance of flammable refrigerants, comprising:

[0068] A sealed cabinet 1 is located in the hazardous area of ​​the laboratory (i.e., the space where the outdoor unit is located), and a positive pressure environment is formed inside it; for example, the positive pressure inside the cabinet is maintained at about 200 Pa; when the positive pressure inside the sealed cabinet 1 is less than the extreme positive pressure value, for example, 50 Pa, the power supply is disconnected; accordingly, the disconnect switch should be located in a safe area outside the laboratory to avoid sparks generated during disconnection.

[0069] It should be noted that the sealed cabinet 1 should have good sealing performance and meet certain sealing requirements. When the internal and external differential pressure is 200Pa, the leakage should be controlled at 0.5 to 3 times the internal volume of the cabinet per hour. For example, for an electrical cabinet with an internal volume of 500L, the leakage should be controlled at 0.25 to 1.5Nm3 / h. The leakage should be adjusted by the first regulating valve 6.

[0070] Optionally, when the temperature inside the hazardous area of ​​the laboratory is very low (e.g., -20°C), the positive pressure cabinet casing should be insulated to avoid excessive temperature differences between the inside and outside, which could cause condensation on the inner wall surface.

[0071] Optionally, 1 to 6 thermocouples should be placed on the inner and outer surfaces of the sealed cabinet, for a total of 2 to 12 thermocouples, to assess whether the cabinet has reached thermal equilibrium.

[0072] Gas source 2, located outside the hazardous area of ​​the laboratory, outputs compressed air at a first specified temperature into the sealed cabinet 1; and / or maintains a specified gas leakage rate in the sealed cabinet 1; preferably, the gas source 2 generates constant pressure compressed air via a pressure reducing valve 4; after the compressed air output from the gas source 2 is adjusted to a specified pressure by the pressure reducing valve 4, it enters the heat exchanger 5 and fully exchanges heat with the air in the hazardous area of ​​the laboratory, and then enters the sealed cabinet 1 via the first regulating valve 6, thereby realizing the entry of compressed air at the first specified temperature into the sealed cabinet 1;

[0073] To further explain, by controlling the temperature of the compressed air entering the sealed cabinet, the heat dissipation of electrical components inside the explosion-proof cabinet can be prevented from affecting the results of the room air conditioning thermal balance test.

[0074] By controlling the amount of gas leakage from the explosion-proof electrical cabinet (achieved by controlling the flow rate of compressed air entering the sealed cabinet), the heat dissipation of electrical components inside the explosion-proof electrical cabinet can be prevented from affecting the results of the room air conditioning thermal balance test.

[0075] Correspondingly, by controlling the temperature of the compressed air entering the sealed cabinet and controlling the amount of gas leakage from the explosion-proof electrical cabinet, the heat dissipation of the electrical components inside the explosion-proof electrical cabinet can be prevented from affecting the results of the room air conditioning thermal balance test.

[0076] For example, if the temperature difference is no more than 5℃, the resulting heat error is 1.5*1.2 / 3600*1.005*(13-7)≈3W. For air conditioners with a cooling or heating capacity of 600W or more, the error is less than 0.5%.

[0077] Accordingly, to avoid condensation inside the positive pressure cabinet, the compressed air should be dry, with a dew point temperature lower than the coolant temperature;

[0078] Preferably, the form of the gas source water vapor mechanism includes, but is not limited to: compressed air output from gas source 2 is adjusted to a specified pressure by pressure reducing valve 4, enters heat exchanger 5 and fully exchanges heat with the air in the hazardous area of ​​the laboratory's outer chamber, and then enters sealed cabinet 1 through first regulating valve 6;

[0079] The first regulating valve 6 is used to regulate the amount of gas leakage from the sealed cabinet 1;

[0080] The bypass valve 7 is connected in parallel with the first regulating valve 6 and is only opened when the electrical cabinet needs ventilation or purging.

[0081] Considering that the key to reducing the impact is to achieve thermal equilibrium, the sealed cabinet 1 does not only require heat dissipation, but also needs to be kept at a constant temperature in order to achieve thermal equilibrium as soon as possible. Therefore, a temperature regulation component is installed inside the sealed cabinet 1.

[0082] The temperature control component is arranged inside the sealed cabinet 1. The input power of the temperature control component is measured by a power meter, and the cooling capacity is measured and calculated by a flow meter and a temperature sensor.

[0083] Accordingly, to further improve safety, differential pressure switches and exhaust systems should also be installed in the hazardous areas of the laboratory. When the differential pressure is too high, a warning should be given and the exhaust system should be activated.

[0084] The required gas leakage rate for the experiment can be obtained in the following ways;

[0085] The allowable heat error caused by compressed air is determined based on the air conditioner's power. Assuming a cooling or heating capacity of 2800W or higher, the allowable heat error caused by compressed air is 0.5%, the compressed air temperature is 35℃, the indoor temperature is 7℃, and the leakage rate is 1.5 Nm. 3 / h, the heat error caused by this portion of compressed air is

[0086] 1.5*1.2 / 3600*1.005*(35-7)≈14W; Therefore, after specifying the allowable heat error caused by compressed air through the following formula, the gas leakage can be calculated in reverse, and then the gas leakage can be obtained by adjusting the first regulating valve 6, so as to avoid the heat leakage of the electrical control cabinet from affecting the test.

[0087] The thermal error caused by compressed air = gas leakage * 1.2 / 3600 * 1.005 * compressed air temperature - laboratory hazardous area temperature.

[0088] Optionally, a first temperature regulation component that can be used in the first embodiment described above includes:

[0089] Fan 8, which is located in an explosion-proof electrical cabinet, is used to accelerate the heat exchange of the indirect cooling coil 9;

[0090] Temperature sensor 10 is located inside an explosion-proof electrical cabinet;

[0091] Electric heating element 11 is installed inside the explosion-proof electrical cabinet to control the temperature inside the cabinet; for example, PTC electric heating is used, and the maximum maintained temperature is below 60°C.

[0092] Alternatively, a second temperature regulation component that can be used in the first embodiment described above may be provided, including:

[0093] Fan 8, which is located in an explosion-proof electrical cabinet, is used to accelerate the heat exchange of the indirect cooling coil 9;

[0094] Temperature sensor 10 is located in the hazardous area of ​​the laboratory.

[0095] The second regulating valve 12 is located at the coolant inlet of the intercooling coil 9 and is used to regulate the cooling volume and control the temperature inside the electrical cabinet.

[0096] It should be noted that the second temperature regulating component provided by the present invention causes flow fluctuations and prolongs the balancing time compared to the first temperature regulating component.

[0097] Furthermore, the temperature setting inside the sealed cabinet should preferably be equal to the temperature of the hazardous area inside the laboratory to shorten the thermal equilibrium time. Considering the typical operating temperature range of electrical components and safety assessments, the operating temperature setting range for the sealed cabinet is 5–35°C. When the internal temperature exceeds this range, the setting value should be made as close as possible to the internal temperature.

[0098] For the two temperature control components mentioned above, it is preferable that the coolant in the indirect cooling coil 9 originates from the same source as the indirect cooling coil 14 in the air conditioning unit of the hazardous area of ​​the laboratory. The coolant supply pipe forms a branch in the hazardous area of ​​the laboratory, and the return pipe forms a confluence in the hazardous area of ​​the laboratory. This structure allows for the calculation of the heat carried away by the coolant by measuring the total supply flow rate, total supply temperature, and total return temperature. This structure can save one flow meter and two temperature sensors, reducing the cost of experimental equipment.

[0099] Preferably, the explosion-proof electrical cabinet is further improved by determining the allowable heat measurement error caused by compressed air based on the lower limit of the air conditioning cooling or heating capacity measured in the heat balance laboratory.

[0100] Preferably, the explosion-proof electrical cabinet is further improved such that the power supply is disconnected when the positive pressure inside the sealed cabinet 1 is less than the positive pressure extreme value.

[0101] Alternatively, the first embodiment described above can be further improved by including:

[0102] Pressure relief valve 3 is installed on the pipeline connecting the sealed cabinet 1 to the inner chamber of the laboratory's hazardous area;

[0103] Differential pressure switch 13 is used to detect the differential pressure between the sealed cabinet 1 and the laboratory hazardous area. If the differential pressure is less than the first specified differential pressure (e.g., 50 Pa), the power supply is disconnected. If the differential pressure is greater than the second specified differential pressure (e.g., 250 Pa), the power supply to the cabinet is disconnected, the power supply is cut off, and an alarm is issued. If the differential pressure is greater than the third specified differential pressure (e.g., 300 Pa), the pressure relief valve 3 is opened.

[0104] In a further improvement to the first embodiment described above, if the temperature of the sealed cabinet 1 is higher than a second specified temperature, for example, 40°C, the power supply is cut off.

[0105] Before powering on, this invention requires multiple air changes and / or purging for a specified duration, opening the bypass valve 7 and the pressure relief valve 3 to increase the air supply. For example, ensure the positive pressure control cabinet is ventilated 5 times (zone 2) or 7 times (zone 1) before powering on. For a volume of 500L, the volumetric flow rate is approximately 2.5 Nm³. 3 / h (zone 2) or 3.5Nm 3 / h(zone1), requires purging for about 1 hour first.

[0106] Further improvements to the first embodiment described above include ensuring good sealing performance of the explosion-proof electrical cabinet. When the differential pressure between the inside and outside of the explosion-proof electrical cabinet is 200 Pa, the leakage rate is approximately 0.5 to 3 times the internal volume of the electrical cabinet per hour.

[0107] Alternatively, in the first embodiment, the pressure relief valve 3 can be a pneumatic valve, an explosion-proof electric valve, or a mechanical valve that can be repeatedly opened, or it can be moved to a safe area outside the laboratory.

[0108] Alternatively, in the first embodiment, the bypass valve 7 can be a pneumatic valve, an explosion-proof electric valve, or can be moved to a safe area outside the laboratory.

[0109] Optionally, in the first embodiment, the differential pressure switch 13 should be able to operate in hazardous zone I or zone II.

[0110] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will also be understood that, unless expressly defined herein, terms such as those defined in a general dictionary shall be interpreted as having the meaning consistent with their meaning in the relevant field context, and not as having an idealized or overly formal meaning.

[0111] The present invention has been described in detail above through specific embodiments and examples, but these are not intended to limit the invention. Many modifications and improvements can be made by those skilled in the art without departing from the principles of the invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. An explosion-proof electrical cabinet for use in the hazardous area of ​​a laboratory with air conditioning and flammable refrigerant thermal balance, characterized in that, include: A sealed cabinet (1) is located in the hazardous area of ​​the thermal balance laboratory, where a positive pressure environment is formed inside. A gas source (2), located outside the hazardous area of ​​the laboratory, outputs compressed air at a first specified temperature into the sealed enclosure (1); and / or maintains a specified gas leakage rate in the sealed enclosure (1); The temperature control component is arranged inside a sealed cabinet (1). The input power of the temperature control component is measured by a power meter, and the cooling capacity is measured and calculated by a flow meter and a temperature sensor. Among them, the compressed air output by the air source (2) is adjusted to the specified pressure by the pressure reducing valve (4), and then enters the heat exchanger (5) to fully exchange heat with the air in the dangerous area of ​​the laboratory's outer chamber, and then enters the sealed cabinet (1) through the first regulating valve (6). The first regulating valve (6) is used to regulate the amount of gas leakage from the sealed cabinet (1); The bypass valve (7) is connected in parallel with the first regulating valve (6) and is opened only when the electrical cabinet needs ventilation or purging; The allowable heat measurement error caused by compressed air is determined based on the lower limit of the air conditioning cooling or heating capacity measured in the heat balance laboratory. The heat measurement error caused by compressed air = gas leakage * 1.2 / 3600 * 1.005 * (compressed air temperature - laboratory hazardous area temperature); The gas leakage amount is obtained by derivation and calculation, and the gas leakage amount is adjusted by the first regulating valve (6).

2. The explosion-proof electrical cabinet as described in claim 1, characterized in that, Also includes: Pressure relief valve (3) is installed on the pipe connecting the sealed cabinet (1) to the hazardous area inside the laboratory. Differential pressure switch (13) is used to detect the differential pressure between the sealed cabinet (1) and the laboratory hazardous area. If the differential pressure is less than the first specified differential pressure, the power supply is disconnected. If the differential pressure is greater than the second specified differential pressure, the power supply in the cabinet is cut off, the gas supply is cut off, and an alarm is issued. If the differential pressure is greater than the third specified differential pressure, the pressure relief valve (3) is opened.

3. The explosion-proof electrical cabinet as described in any one of claims 1 to 2, characterized in that: Air source (2) outputs compressed air at constant pressure.

4. The explosion-proof electrical cabinet as described in any one of claims 1 to 2, characterized in that: If the positive pressure inside the sealed cabinet (1) is less than the positive pressure extreme value, the power supply will be disconnected.

5. The explosion-proof electrical cabinet as described in any one of claims 1 to 2, characterized in that, The temperature control components include: The fan (8) is arranged in the explosion-proof electrical cabinet to accelerate the heat exchange of the intercooling coil (9); Temperature sensor (10), which is arranged in the explosion-proof electrical cabinet; In addition, an electric heating element (11) and / or a second regulating valve (12); Electric heating (11) is arranged inside the explosion-proof electrical cabinet to control the temperature inside the explosion-proof electrical cabinet; The second regulating valve (12) is located at the coolant inlet of the intercooler coil (9) and is used to regulate the cooling volume in the electrical cabinet.

6. The explosion-proof electrical cabinet as described in claim 5, characterized in that, The temperature control components include: The coolant of the intercooling coil (9) should be from the same source as the intercooling coil (14) of the air conditioning cabinet in the hazardous area of ​​the laboratory. The coolant supply pipe forms a branch in the hazardous area of ​​the laboratory, and the return pipe forms a confluence in the hazardous area of ​​the laboratory.

7. The explosion-proof electrical cabinet as described in any one of claims 1 to 2, characterized in that: If the temperature of the sealed cabinet (1) is higher than the second specified temperature, the power supply will be cut off.

8. The explosion-proof electrical cabinet as described in any one of claims 1-2, characterized in that: When the differential pressure between the inside and outside of the explosion-proof electrical cabinet is 200Pa, the leakage range is 0.5 to 3 times the internal volume of the electrical cabinet per hour.

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