JP2023164375A - Test chamber and test method - Google Patents

Abstract

To provide a test chamber and an operation method of the test chamber that allow a combustible cooling medium to be used safety.SOLUTION: A test chamber includes a test space (43). The test space is thermally insulated, can be sealed from an ambient environment, and holds a test material. The test chamber further includes an engine compartment (44) and a temperature control device for controlling the temperature in the test space. The temperature control device includes a cooling device. The cooling device includes a cooling circuit having a cooling medium, a heat exchanger (52), a compressor, a condenser, and an expansion element. The cooling circuit is disposed in the engine compartment at least partially together with the compressor. The heat exchanger includes a protective barrier (56). The protective barrier tightly seals a cooling medium pipe (53) of the cooling circuit for the test space in the test space.SELECTED DRAWING: Figure 5

Description

The present invention relates to methods and test chambers for air conditioning, in particular temperature controlled chambers, climate chambers or the like. The test chamber comprises a test space, which can be sealed against the surrounding environment and is insulated, and in addition is for holding the test material. The test chamber further includes a test space, an engine compartment, and a temperature control device for controlling the temperature of the test space. The temperature control device has a cooling system that has a cooling circuit that includes a refrigerant, a heat exchanger, a compressor, a condenser, and an expansion element. The cooling circuit is also located at least partially within the engine compartment together with the compressor, and the heat exchanger is located at least partially or entirely within the test space.

Test chambers of this type are widely used for monitoring physical and/or chemical properties of objects, especially devices. Accordingly, temperature test consoles or climate test consoles are known in which the internal temperature can be set in the range of -50 degrees Celsius to 180 degrees Celsius. The climatic test console may additionally be set with desired climatic conditions to which the device or test material will be exposed for a predetermined period of time. Test spaces that receive test materials to be tested typically have air circulation channels to control the temperature within the test space. The air circulation channel forms an air treatment space within the test space, and a heat exchanger for heating or cooling the air flowing through the air circulation channel or the test space is disposed inside the air treatment space. . For this purpose, the fan sucks the air present in the space and directs it to a corresponding heat exchanger located in the air circulation channel. It is thus possible to control the temperature of the test material or to subject it to predetermined temperature changes. During the test, the temperature can vary between maximum and minimum temperatures. A test chamber of this kind is known from US Pat.

European Patent Application No. 0344397

The refrigerant used in the cooling circuit should have a relatively low CO2 equivalent value, i.e. the relative global warming potential (GWP) should be low, in order to avoid indirect damage to the natural environment through the emissions of the refrigerant. should be as low as possible. As a result of legislation, refrigerants must not contribute significantly to atmospheric ozone layer depletion or global warming. Essentially, therefore, no fluorinated gas or fluoride should be used as a refrigerant, and for this reason natural refrigerants such as carbon dioxide (CO2) are considered as an option. The disadvantage of these low-GWP refrigerants is that they exhibit significantly lower cooling capacity than relatively high-GWP refrigerants in some temperature ranges in which the cooling circuit is concerned. be. While it is known that hydrocarbons can be used as refrigerants, they are often highly flammable, which is a disadvantage. Flammability is the property of a refrigerant to react with surrounding oxygen with the release of heat. Refrigerants are flammable, in particular if they are classified in fire class C of the European standard DN2, in the version valid at the priority date of the present application, or in classes A2, A2L and A3 of the German industrial standard DIN 378. The filling, transportation and operation of cooling circuits and test chambers becomes more complex when flammable refrigerants are used because of the need to comply with safety regulations. An important issue is the possibility of cooling circuit leakage within the test volume where electrical resistance heaters and other electrically powered devices such as test materials may be located. In the event of a leak, an explosion could occur.

The present aim of the invention is therefore to propose both a test chamber and a method of operating the test chamber that also allows safe use of flammable refrigerants.

This object is achieved by a test chamber with the features of claim 1 and a method with the features of claim 16.

A test chamber for air conditioning, in particular a temperature-controlled chamber, a climate-controlled chamber or the like, according to the invention comprises a test space, which can be sealed against the surrounding environment; It is insulated to hold the test material. The test chamber further includes an engine compartment tightly sealed and spatially separated from the test space, and a temperature control device for controlling the temperature of the test space. The temperature control device has a cooling system that has a cooling circuit that includes a refrigerant, a heat exchanger, a compressor, a condenser, and an expansion element. Additionally, the cooling circuit is located at least partially within the engine compartment together with the compressor, and the heat exchanger is located at least partially or entirely within the test space. The heat exchanger is formed with a guard wall, which tightly seals the refrigerant pipes of the cooling circuit in and against the test space.

The test chamber according to the invention generally allows any refrigerant to be used safely in the cooling circuit, thus making it possible to take advantage of the advantages of explosive refrigerants. Therefore, within the test sequence, a higher temperature is achieved in the test space, which heats the air in the test space by means of the temperature control device. At the same time, the refrigerant within the heat exchanger is also heated, thereby causing thermal expansion of the refrigerant within the heat exchanger. Since the heat exchanger is at least partially located in the test space, if a leak occurs, in particular a heat exchanger leak, the leak may represent a leakage of refrigerant in the test space. . Since air is usually present in the test space, an explosive atmosphere can easily be created as a result of the presence of electrical resistance heating elements, which may be present during operation, or There is a risk that it may combine with other devices in the space and cause an explosion.

In order to prevent this, the invention intends to form a heat exchanger with a protective wall. The protective wall tightly seals the refrigerant pipes of the cooling circuit, which of course also pass through the heat exchanger. If a leakage of the refrigerant pipes of the cooling circuit occurs in the vicinity of the refrigerant pipes where the refrigerant pipes pass through the heat exchanger or within the test space, the protective wall prevents the refrigerant from exiting the test space; and/or prevent entry into the test space. A guard wall is another structural device designed as an addition to or independent of the cooling circuit to prevent leaking refrigerant from escaping from the refrigerant pipes into the test space. Therefore, the protective wall can be designed in various forms. Overall, it makes it possible to prevent contamination of the protective wall by the refrigerant and, as a result, to suppress the possibility of the formation of an explosive atmosphere. Furthermore, when opening the door to the test space, for example, the personnel are protected from refrigerants that may be present in the test space and are harmful to health.

The refrigerant may be flammable, in which case it may preferably be a refrigerant selected from the group of hydrocarbons or a refrigerant mixture of hydrocarbons. As a result, the refrigerant may be a refrigerant that is free of fluorinated hydrocarbons, is flammable, and/or consists of only a single component. For example, the refrigerant can be propane, ethane, ethylene, propene, isobutane, butane or the like. The refrigerant may also be a refrigerant mixture consisting of a hydrocarbon and/or the components mentioned above, or a refrigerant mixture comprising mainly hydrocarbons. Furthermore, the refrigerant may be free of fluorocarbons. This makes it possible to meet future regulatory requirements for refrigerants and to suppress the disadvantages of fluorinated hydrocarbons. Further, the refrigerant achieves a room temperature in the test space in a temperature range of -40 degrees Celsius to 180 degrees Celsius, preferably -70 degrees Celsius to 180 degrees Celsius, particularly preferably -85 degrees Celsius to 200 degrees Celsius. It can also be applied to It also becomes possible to reduce the GWP of the coolant used in the test chamber to a minimum. The test chamber cooling system may comprise a vapor compression refrigeration system having one or two refrigerants, typically one stage, two stage, or continuous multistage. However, in this case the refrigerant that is led into the test space through the heat exchanger is important.

The protective wall may be designed as a casing that seals the refrigerant pipes in the test space to the test space. For example, the heat exchanger described above may be designed as a double-walled heat exchanger or an evaporator. For example, the above-mentioned casing may be arranged at the rear of the test space or integrated into the test space there, and therefore designed to be arranged without direct contact with the heat exchanger itself. However, it is advantageous if the housing is formed on the heat exchanger or is a component of the heat exchanger. In this way, the heat exchanger can be designed with fins in direct contact with the atmosphere of the test space to improve heat exchange.

Said casing may have a tube, in which case a portion of said tube surrounds the refrigerant pipe. In that case, the tube may surround the refrigerant pipe with a gap therebetween, and the refrigerant pipe is preferably in contact with the inner wall of the tube. The tubes may coaxially surround the refrigerant pipes, for example, particularly where the refrigerant pipes may be exposed to the test volume. The refrigerant pipe can be formed in the test space from a plurality of tube-shaped pipe sections or by intermittent pipe tubes. The pipe tube may be helical and/or screw-shaped, or may be tortuous or curved. The tube surrounding the refrigerant pipe may further be formed with fins for improved heat exchange with the atmosphere of the test space. If an air gap exists between the refrigerant pipe and the tube, the refrigerant that may leak from the refrigerant pipe can enter said air gap instead of into the test space. It is further advantageous if at least part of the refrigerant pipe rests on the inner wall of the tube. The heat exchange between the refrigerant pipe and the tube is then improved while the refrigerant pipe is structurally separated from the inner wall of the tube. However, it is further possible that instead of several tubes, one continuous tube surrounds the refrigerant pipe in the test space.

The casing of the refrigerant pipe may form a tightly sealed leakage space, in which case said leakage space surrounds the refrigerant pipe, at least in the test space. The refrigerant that may leak from the refrigerant pipe enters the leakage space and is collected there, and no further refrigerant leaks out of the leakage space. In this context, the leakage space may be located only within the test space or within the test space and within the engine compartment. Typically, the engine compartment may be spatially separated from the test volume and tightly sealed thereto. Additionally, the leakage space may be designed to withstand pressures that may typically be present within refrigerant pipes. In this way, the leakage space described above can easily be used to collect refrigerant leaking from the leakage pipe in the region of the test space.

The leakage space may be filled with a convective fluid, either liquid or gas, in which case the casing may have a safety pressure valve. The safety pressure valve can be connected to the leakage space, and convective fluid can be directed into the engine compartment through the safety pressure valve. The convective fluid may be selected based on the size of the leakage space between the refrigerant pipe and the inner wall of the leakage space. The convective fluid may be a protective gas that prevents the formation of an explosive atmosphere. For example, the convective fluid may be nitrogen, since nitrogen changes very little over a temperature range of 80 degrees Celsius to 180 degrees Celsius, making it particularly suitable for test chamber applications. It is from. Furthermore, a safety pressure valve may be connected to the leakage space, in which case the safety pressure valve is capable of discharging the contents of the leakage space if the pressure defined within the leakage space becomes too high. , into the engine compartment or alternatively into the surrounding environment of the test chamber. If the engine compartment is tightly sealed from the test space, the test space will not become contaminated with refrigerant or other convective fluids present in the leakage space. For example, the outlet pressure of the safety pressure valve may be selected to be below the typical pressure of the refrigerant in the refrigerant pipe.

The casing may have a pressure sensor that can be connected to the leakage space, in which case the cooling device can be shut down when the pressure in the leakage space increases. A pressure sensor allows the pressure within the leak space to be measured or monitored. When the pressure increases due to the refrigerant leaking from the refrigerant pipe into the leakage space, the operation of the cooling device can be terminated or the cooling device can be stopped. Therefore, it is possible to prevent even more refrigerant from leaking from the refrigerant pipe and flowing into the leakage space. Nevertheless, detection of leaks in refrigerant pipes is also easy. Also important for determining the presence or absence of a leak is the comparison of the pressure measured by the pressure sensor with the pressure that would generally be expected from the current prevailing temperature of the heat exchanger.

The valve box of the cooling device may be located within the engine compartment, in which case the valve box may be open to the engine compartment. In the valve box, connections for pipe tubes of refrigerant pipes of the cooling circuit may be located. The valve within the valve box may be an expansion element. If the valve box is designed to be open to the engine compartment, it can be ensured that no refrigerant can be trapped in the valve box in the event of a leakage of the refrigerant pipe within the valve box. Furthermore, it is also possible to form a protective wall so that the refrigerant leaking from the refrigerant pipe in the test space is guided to the valve box. If the heat exchanger is designed with a casing or with tubes surrounding refrigerant pipes or the like, the open ends of the tubes extend into the valve box. It may be left open. The casing may also be formed to protrude somewhat from the heat exchanger, to the extent that the casing protrudes from the rear wall of the test space into the engine compartment or valve box. The refrigerant pipes themselves may be designed in such a way that they run freely within the valve box, ie without protective walls or casings. Furthermore, the design of the valve box that is open in the direction of the engine compartment makes it possible to more easily identify leaks in the area of the valve box.

The test chamber may have a monitoring unit, in which case the monitoring unit may include a gas monitoring system having a gas detection sensor located within the engine compartment. The gas detection sensor may be a heat tone sensor. The gas detection sensor may be connected to a monitoring unit that further processes impulses or data from the gas detection sensor. If the gas detection sensor is arranged in the engine compartment, it is possible there to detect refrigerants, for example hydrocarbons, that have leaked into the engine compartment. If a leaking refrigerant is detected, the entire test chamber or cooling device or temperature control device can be shut down via the monitoring unit. What this means is that the possibility of ignition is suppressed and further leakage of refrigerant may be prevented.

The gas detection sensor is preferably located lower than the lowest engine compartment opening. Therefore, the gas detection sensor is preferably located at the bottom of the engine compartment. Leaked refrigerants or hydrocarbons are heavier than air and will sink to the bottom, where they can be safely detected. The possible opening in the engine compartment or the opening of the engine compartment in the casing of the test chamber may be arranged above the bottom surface, for example 10 cm above the bottom surface of the engine compartment. What this means is that no leaking refrigerant can leave the engine compartment without being detected.

The monitoring unit may have optical and/or acoustic signaling means, with which leakage of refrigerant from the refrigerant pipe may be signaled. . In that case, the personnel can directly intervene in the operation of the test chamber in this embodiment or, in case of imminent danger, leave the surrounding environment of the test chamber. In addition to signaling malfunctions or refrigerant leaks, the transmission of signals or data to computers or handheld terminal devices or the like used for monitoring and control may also take place via the monitoring unit.

The test chamber may have emergency ventilation equipment, in which case the emergency ventilation equipment may include a fan. The fan is located within the engine compartment and can be used to draw air from the engine compartment. Furthermore, the outlet channel of the emergency ventilation equipment for air can be located outside the engine compartment. Emergency ventilation equipment may be activated when refrigerant exits the refrigerant pipe or when refrigerant is detected. The fan may be configured for use in explosive areas, particularly in accordance with ATEX product guidelines and/or ATEX operational guidelines. Since the temperature in the engine compartment essentially corresponds to or is only slightly higher than the ambient air temperature, ATEX-certified fans or fan motors should be used for ventilation of the engine compartment. This is possible. This is particularly advantageous since it is not possible to use ATEX-certified fans for emergency ventilation of the test space due to the very high prevailing temperatures that can be achieved. . ATEX-certified fans are typically certified to carry temperatures between -20 degrees Celsius and 60 degrees Celsius, so that temperatures between -50 degrees Celsius and 180 degrees Celsius are typically achieved within the test space. It does not cover a range of temperatures. An ATEX-certified fan is one that complies with the ATEX guidelines of the European Union, in particular with the ATEX Product Guideline 2014/34/EU and/or the ATEX Operational Guideline 1999/92/EG, which are the versions in force at the priority date of this application. device or protection system. Such a fan can be installed in the engine compartment at the bottom of the control cabinet and draw air from the engine compartment without any complicated design. The emergency ventilation equipment can be designed in such a way that no pressurized tube of the outlet channel is placed in the engine compartment. It is therefore possible that the outlet channel is led outside the engine compartment and that the potentially explosive air and refrigerant mixture is outside the test chamber in the outlet channel. However, it is generally also possible to arrange the fan outside the engine compartment.

The test chamber may have a dehydration cue, in which case the cue may consist of other refrigerant pipes of a cooling circuit arranged in a water bath within the test space. Furthermore, the other refrigerant pipe in question can be surrounded by other tubes, at least in the test space. Furthermore, the other tube in question can form another leakage space opening into the engine compartment. Dehydration cues located within the water bath within the test space may be used to achieve specific climatic conditions. A dehydration cue or other refrigerant pipe may be connected to the refrigeration circuit and exposed to refrigerant. Since leakage of the other refrigerant pipes mentioned above may also occur, the other leakage spaces mentioned above may likewise accommodate other refrigerant pipes or surround the other refrigerant pipes as another protective wall. But that's fine. The other leak spaces mentioned above may be formed by the other tubes mentioned above. The other tubes mentioned above may be open outside the water bath, connected via screw connections or flanges to the tubes of the test space, or, when open, open into the engine compartment. The leakage space can be directed into the engine space such that leaked refrigerant can enter the engine space from the leakage space and be detected there.

The temperature control device may include a heating device, in which case the heating device may include an electrical resistance heater within the test space. Electrical resistance heaters may consist of one or more resistance heating elements. Accordingly, the temperature control device may be used to increase the temperature within the test space.

A temperature in the range of -50 degrees Celsius to 180 degrees Celsius, preferably of -80 degrees Celsius to 180 degrees Celsius, particularly preferably of -80 degrees Celsius to 200 degrees Celsius, is achieved in the test space by the above-mentioned temperature control device. , is feasible.

In a method for operating a test chamber for air conditioning, in particular a temperature-controlled chamber, a climate chamber or the like, the test chamber comprises a test space, the test space being sealed against the surrounding environment. and is insulated to receive the test material. The test space is temperature controlled using a test chamber temperature control device. The temperature control device has a cooling system, the cooling system having a cooling circuit having a refrigerant, a heat exchanger, a compressor, a condenser, and an expansion element. The cooling circuit is located, together with the compressor, at least partially within the engine compartment of the test chamber. The heat exchanger described above is located at least partially or entirely within the test space. The refrigerant pipes of the cooling circuit are tightly sealed in the test space by the protective wall of the heat exchanger with respect to the test space. Regarding the advantageous effects of the above method according to the invention, reference is made to the description regarding the advantages of the test chamber according to the invention.

Before starting the temperature control device and/or during operation of the temperature control device, the monitoring unit of the test chamber can monitor the pressure in the casing forming the protective wall by means of a pressure sensor of the casing; And/or the atmosphere in the engine compartment can be monitored by a gas detection sensor of a gas monitoring system of a monitoring unit arranged in the engine compartment. The monitoring unit of the test chamber may also be formed by a control device of the test chamber, which in turn may be formed by a computer or a programmable logic controller. Prior to putting into operation the temperature control device or the test chamber itself, in a first step it may be provided that the monitoring unit first performs a functionality test of the test chamber. This functionality test is performed by pressure sensors and/or gas detection sensors interrogated by a monitoring unit. It can therefore be ensured that there is no refrigerant in the protective wall of the heat exchanger and/or in the engine compartment when starting the operation of the temperature control device. A monitoring unit may also be connected between the test chamber power source and the main switch. What this means is that the monitoring unit can be activated before the test chamber is powered via the main switch. The monitoring unit can then monitor the pressure and/or atmosphere.

The above-mentioned monitoring unit is capable of permitting the activation of the temperature control device or the temperature control device when the pressure in the casing complies with the regulations and/or when the atmosphere in the engine compartment complies with the regulations. It is possible to continue operating. After the pressure and atmosphere have become monitored by the monitoring unit, in the second step two scenarios can occur. That is, two scenarios can occur: authorization of activation of the test chamber via the main switch, or continued operation of the test chamber, if the monitoring unit is performing monitoring during operation of the test chamber.

Furthermore, the above-mentioned monitoring unit prevents the activation of the temperature control device or the operation of the temperature control device when the pressure in the casing increases and/or the atmosphere in the engine compartment is hazardous. It is possible to stop. For this second scenario, the monitoring unit can detect the leak before the test chamber is activated or during operation of the test chamber, and when necessary, the monitoring unit activates the test chamber. Either prevent it or stop its operation. Even hazardous atmospheres below the lower explosive threshold can be detected.

The monitoring unit can activate the emergency ventilation equipment of the test chamber and/or release the pressure in the casing via the safety pressure valve of the casing. When refrigerant is detected by the gas detection sensor, the monitoring unit can start the fan immediately after detecting the refrigerant to suck air from at least the engine compartment. Optionally, it is also possible to provide for detecting the amount of refrigerant in the air by means of a gas detection sensor. It is therefore also possible not to start the fan until there is a real risk of forming an explosive mixture. Furthermore, the monitoring unit may also be used to power down the temperature control device if refrigerant is detected. In this way, further leakage of refrigerant from the refrigerant pipes and/or ignition of refrigerant within the engine compartment can be prevented. Furthermore, excess pressure in the protective wall and/or in the casing of the heat exchanger can be relieved by a safety pressure valve. Release of excess pressure may also be detected by the monitoring unit. What this means is that leaks can be identified before refrigerant is detected by the gas detection sensor.

Emergency ventilation equipment may be operated until the gas monitoring system detects a compliant atmosphere. This therefore ensures that the test chamber is operated again only when no refrigerant is present in the engine compartment.

Further advantageous embodiments of the method can be derived from the description of the features of the dependent claims referring to the device according to claim 1.

In the following, preferred embodiments of the invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 shows a perspective view of one embodiment of a heat exchanger. FIG. 2 shows a schematic cross-sectional view of a second embodiment of a heat exchanger. Figure 3 shows a front view of the rear wall of the test space. FIG. 4 shows a schematic principle diagram of an embodiment of a dehydration cue. FIG. 5 shows a schematic partial cross-sectional view of a first embodiment of a test chamber. FIG. 6 shows a schematic principle diagram of a second embodiment of the test chamber. FIG. 7 shows a schematic principle diagram of a second embodiment of the test chamber in a partial perspective view.

FIG. 1 shows a principle perspective view of a first embodiment of a heat exchanger 10 arranged in the test volume of a test chamber (not shown). Heat exchanger 10 has refrigerant pipes 12 as part of a cooling circuit (not shown) and has fins 12 . A pipe portion 13 of the refrigerant pipe 11 passes through the fins 12 . Thus, the air can be temperature controlled or cooled within the test space via the fins 12. Furthermore, the heat exchanger 10 is formed with a casing 14 . A mounting plate 15 is arranged on the casing 14 for fixing the heat exchanger 10 on a wall (not shown) in the test space.

FIG. 2 shows a schematic cross-section or principle view of a heat exchanger 16 which is likewise arranged in a test space 17 of a test chamber (not shown). Heat exchanger 16 has refrigerant pipes 18 and fins 19 for controlling the air temperature within test space 17 . Furthermore, the heat exchanger 16 is formed with a protective wall 20 . The protective wall 20 tightly seals the refrigerant pipes 18 of the cooling circuit (not shown) of the test chamber in the test space 17 to the test space 17 . The protective wall 20 is designed as a casing 21 of the refrigerant pipe 18 . The casing 21 has a tube 22 surrounding a portion of the refrigerant pipe 18. A gap 23 is formed between the refrigerant pipe 18 and the tube 22. However, at least a portion of the refrigerant pipe 18 may contact the inner wall 24 of the tube 22. Because the refrigerant pipe 18 is winding, the jacket 26 of the casing 21 is provided at the open end 25 of the tube 22, where the jacket 26 covers the refrigerant pipe 18 and connects the refrigerant pipe 18 to the tube. 22 to form a tight seal against the test space 17. The refrigerant pipe 18 passes through the jacket 26 in such a manner that the refrigerant pipe 18 extends freely within the engine compartment 27 of the test space without being covered in any way. This is made possible by the engine compartment 27 being tightly sealed by the test space 17.

The casing 21 also forms a leakage space 28 that is tightly sealed against the surrounding environment. Leakage space 28 is filled with convective fluid (not shown). Furthermore, the casing 21 has a pressure sensor 29. The pressure sensor 29 is connected to the leakage space 28 and measures the pressure in the leakage space 28 . If refrigerant leaks from the refrigerant pipe 18 into the leakage space 28 , the pressure within the leakage space 28 will increase and this pressure can be detected by the pressure sensor 29 . This makes it possible to detect possible leaks in the refrigerant pipes 18 in this area. Additionally, the heat exchanger 16 and/or the leakage space 28 may have a safety pressure valve (not shown) in which case, upon exceeding an unacceptable maximum pressure, the convective fluid can be guided into the engine compartment 27 via the.

Figure 3 shows the test space rear wall or wall 30 of the test space (not shown) of the test chamber. A heat exchanger (also not shown), such as the one shown in FIG. 1, may be attached to the wall 30 via fastening points 31. In such a case, the heat exchanger casing may protrude into the engine compartment through the opening 32 in the wall 30. The casing may be sealed against the wall 30, for example by a sealing mass. It can thus be ensured that the refrigerant pipes do not extend openly in the test space.

FIG. 4 schematically illustrates a test space 33 with a dehydration cue 34. The dewatering cue is formed from another refrigerant pipe 36 of the cooling circuit, which is arranged in a water bath 35 in the test space 33 . Another refrigerant pipe 36 is surrounded by another tube 37 and another jacket 38 in the test space 33 . The further casing 39 formed in this way forms a further leakage space 30 that opens into the engine compartment 41 or into the engine compartment 41 .

FIG. 5 is a schematic partial cross-sectional view of a test chamber 42 having a test space 43 and an engine compartment 44. FIG. In this embodiment, the test space 43 is formed with a bottom portion 45 and a rear wall 46 . Furthermore, the test space 43 is tightly sealed to the engine compartment 44 by a wall 47 . Between the rear wall 46 and the wall 47 an air circulation channel 48 is formed, through which the air of the test space 43 can be guided and conditioned. be. A dehydration cue 50 having a heat insulating material 49 and a water bath 51 is arranged below the bottom part 45 . A heat exchanger 52 with a refrigerant pipe 53 and a heating device 54 with an electric heating element 55 are arranged in the air circulation channel 48 . The heat exchanger 52 is formed with a protective wall 56, shown only schematically, which seals the refrigerant pipe 53 tightly against the test space 43.

The combination of FIGS. 6 and 7 shows a test chamber 57 having a test volume 59 tightly sealed to the surrounding environment 58 and an engine compartment 60 tightly sealed to the test volume 59. A heat exchanger 61, such as one of the heat exchangers described above, formed with a protective wall (not shown) is arranged in the test space 59. Furthermore, a compressor 62 , a condenser 63 , and a test space fan 64 for circulating the air present in the test space 59 are arranged in the engine compartment 60 . Furthermore, a valve box 65 is arranged in the engine compartment 60, inside of which an expansion element (not shown) and further valves of the cooling circuit (not shown) are arranged. The valve box 65 is open to the engine chamber 60. A gas detection sensor 67 is located within the engine compartment 60 and adjacent to the bottom 66 of the engine compartment 60 . Furthermore, openings 68 and 69 are formed in the engine compartment 60 for ventilating the engine compartment 60.

If refrigerant flows into the engine compartment 60 as a result of a leak in the refrigerant pipes within the heat exchanger 61, the refrigerant will sink towards the bottom 66 and can be detected by the gas detection sensor 67.

Furthermore, an emergency ventilation facility 70 having an outlet pipe 72 is provided within the engine compartment 60 . In this example, outlet pipe 72 extends outside of engine compartment 60 within ambient environment 58 . If a refrigerant is detected in the engine compartment 60 via the gas detection sensor 67, the air present in the engine compartment 60 can be transported together with the refrigerant into the surrounding environment 68 by the emergency ventilation equipment 70.

Claims (21)

A test chamber (42, 57) for air conditioning, in particular a temperature-controlled chamber, a climatic chamber or the like, said test chamber comprising a test space (17, 33, 43, 59) and in which said test The space can be sealed to the surrounding environment (58), is insulated and is for receiving test material, said test chamber further comprising an engine compartment (27, 41, 44, 60) and said A temperature control device for controlling the temperature of the test space is provided, and the temperature control device has a cooling device, and the cooling device includes a refrigerant, a heat exchanger (10, 16, 52, 61), a compressor. a cooling circuit having a compressor (62), a condenser (63), and an expansion element, the cooling circuit being located at least partially within the engine compartment together with the compressor; in a test chamber (42, 57), in which an exchanger is located at least partially or wholly within said test space;
The heat exchanger is formed with a protective wall (20, 56), which protects the refrigerant pipes (11, 18, 53) of the cooling circuit within the test space and into the test space. A test chamber, characterized in that the test chamber is tightly sealed against the air. Test chamber according to claim 1, characterized in that the refrigerant is flammable and that the refrigerant is preferably a refrigerant selected from the group of hydrocarbons or a refrigerant mixture of hydrocarbons. characterized in that said protective wall (20, 56) is designed as a casing (14, 21) sealing said refrigerant pipe (11, 18, 53) in said test space with respect to said test space. The test chamber according to claim 1 or 2. Said casing (14, 21) has a tube (22), a portion of said tube surrounding said refrigerant pipe (11, 18, 53), said tube having said refrigerant pipe between it. 4. Test chamber according to claim 3, characterized in that it is surrounded by an air gap (23) and that the coolant pipe is preferably in contact with the inner wall (24) of the tube. The casing (14, 21) of the refrigerant pipe (11, 18, 53) forms a tightly sealed leakage space (28), which allows the refrigerant pipe to pass at least into the test space (17). , 33, 43, 59). The leakage space (28) is filled with a convective fluid, which is liquid or gas, and the casing (14, 21) has a safety pressure valve, the safety pressure valve being connected to the leakage space. 6. Test chamber according to claim 5, characterized in that the convective fluid can be led into the engine chamber (27, 41, 44, 60) via the pressure valve. the casing (14, 21) has a pressure sensor connected to the leakage space (28), the operation of the cooling device being able to be stopped when the pressure in the leakage space increases; Test chamber according to any one of claims 3 to 6, characterized in that: A valve box (65) of the cooling device is disposed within the engine compartment (27, 41, 44, 60), and the valve box is open to the engine compartment. A test chamber according to any one of claims 1 to 7. A gas monitoring system, wherein the test chamber (42, 57) has a monitoring unit, the monitoring unit having a gas detection sensor (67) located in the engine compartment (27, 41, 44, 60). Test chamber according to any one of claims 1 to 8, characterized in that it comprises: The gas detection sensor (67) is arranged lower than the opening (68, 69) of the engine compartment (27, 41, 44, 60) located at the lowest position. 9. The test chamber according to 9. The monitoring unit has optical signal means and/or acoustic signal means, by means of which the leakage of the refrigerant from the refrigerant pipe (11, 18, 53) is signaled. Test chamber according to claim 9 or 10, characterized in that the test chamber is delivered. The test chamber (42, 57) has an emergency ventilation facility (70), the emergency ventilation facility having a fan (71), which fan is connected to the engine compartment (27, 41, 44, 60). ), air is sucked from the engine compartment using the fan, and an outlet channel (72) of the emergency ventilation equipment for the air is located outside the engine compartment; Test chamber according to any one of claims 1 to 11, characterized in that: The test chamber (42, 57) has a dehydration cue (34, 50), the dehydration cue being arranged in a water bath (35, 51) within the test space (17, 33, 43, 59). The other refrigerant pipe (36) of the cooling circuit is surrounded, at least in the test space, by another tube (37), which tube is connected to the engine compartment (37). 13. Test chamber according to any one of claims 1 to 12, characterized in that it forms a further leakage space (40) opening into the test chamber (27, 41, 44, 60). 14. According to any one of claims 1 to 13, characterized in that the temperature control device comprises a heating device (54), said heating device comprising an electrical resistance heater (55) in the test space. Test chamber as described. A temperature in the range of -50 degrees Celsius to 180 degrees Celsius, preferably of -80 degrees Celsius to 180 degrees Celsius, particularly preferably of -80 degrees Celsius to 200 degrees Celsius, is applied to said test space (17, 33, 43, 59). 15. Test chamber according to any one of claims 1 to 14, characterized in that it is realizable by the temperature control device within ). A method for operating a test chamber (42, 57) for air conditioning, in particular a temperature-controlled chamber, a climate chamber or the like, said test chamber comprising a test space (17, 33, 43, 59). ), the test space is capable of being sealed to the surrounding environment (58), is insulated and for receiving test material, and the test space is configured to use a temperature control device of the test chamber. The temperature control device has a cooling device, and the cooling device includes a refrigerant, a heat exchanger (10, 16, 52, 61), a compressor (62), and a condenser (63). ), and a cooling circuit having an expansion element, said cooling circuit being located, together with said compressor, at least partially within an engine compartment (27, 41, 44, 60) of said test chamber. and the heat exchanger is located at least partially or entirely within the test space,
that the refrigerant pipes (11, 18, 53) of the cooling circuit are tightly sealed in the test space by the protective walls (20, 56) of the heat exchanger with respect to the test space; Characterized method. A monitoring unit of the test chamber (42, 57) monitors the pressure in the casing forming the protective wall (20, 56) by means of a pressure sensor (29) in the casing and/or monitors the pressure in the casing forming the protective wall (20, 56) and/or 27, 41, 44, 60) is monitored by a gas detection sensor (67) of a gas monitoring system of the monitoring unit arranged in the engine compartment. . When the monitoring unit determines that the pressure within the casing (14, 21) complies with regulations and/or the atmosphere within the engine compartment (27, 41, 44, 60) complies with regulations. 18. The method of claim 17, further comprising allowing the temperature control device to start or continuing operation of the temperature control device. The monitoring unit detects when the pressure in the casing (14, 21) is increasing and/or when the atmosphere in the engine compartment (27, 41, 44, 60) is dangerous. 18. Method according to claim 17, characterized in that the activation of a temperature control device is prevented or the operation of the temperature control device is stopped. The monitoring unit activates the emergency ventilation equipment (70) of the test chamber (42, 57) and/or releases the pressure in the casing (14, 21) via a safety pressure valve of the casing. 20. The method according to claim 19, characterized in that . 21. Method according to claim 20, characterized in that the emergency ventilation installation (70) is operated until the gas monitoring system detects a compliant atmosphere.

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