TEST CHAMBER AND PROCEDURE

Description

[0001] The invention relates to a method and a test chamber for conditioning air, in particular a temperature control chamber, climate chamber or the like, wherein the test chamber comprises a test space which can be closed off from the environment and is temperature-insulated for accommodating test material, and a temperature control device for temperature control of the test space, wherein the temperature control device has a heating device and a cooling device with a cooling circuit with a refrigerant, a heat exchanger in the test space, a compressor, a condenser and an expansion element, wherein the test chamber is designed with a machine room which is spatially separated from the test space, wherein the cooling circuit with the compressor is arranged at least partially in the machine room.

[0002] Such test chambers are regularly used to test the physical and / or chemical properties of objects, particularly devices. Temperature test cabinets or climatic test cabinets are known, within which temperatures can be set within a range of -50 °C to +180 °C. In climatic test cabinets, additional desired climatic conditions can be set, to which the device or test object is then exposed for a defined period of time. The temperature of a test chamber containing the test object to be tested is regularly controlled in a recirculation duct within the test chamber. The recirculation duct forms an air treatment chamber within the test chamber, in which heat exchangers are arranged to heat or cool the air flowing through the recirculation duct or the test chamber. A fan or ventilator draws in the air in the test chamber and directs it through the recirculation duct to the respective heat exchangers.The test sample can be tempered or subjected to a defined temperature change. During a test interval, for example, the temperature in the test chamber can fluctuate between a maximum and a minimum temperature. Such a test chamber is known from EP 0 344 397 A2.

[0003] The refrigerant used in a cooling circuit should have a relatively low CO2 equivalent, i.e. a relative greenhouse potential or global warming potential (GWP) should be as low as possible to avoid indirect damage to the environment caused by the refrigerant if released. Due to legal regulations, a refrigerant must not contribute significantly to ozone depletion in the atmosphere or global warming. For example, fluorinated gases or fluorinated substances should essentially not be used as refrigerants, which is why natural refrigerants such as carbon dioxide (CO2) are suitable. The disadvantage of such refrigerants with low GWP is that these refrigerants sometimes have a significantly reduced cooling capacity in the temperature ranges relevant to a cooling circuit compared to refrigerants with a comparatively higher GWP.While it is also known to use hydrocarbons as refrigerants, the disadvantage here is that hydrocarbons are highly flammable. Flammability here refers to the property of the refrigerant to react with ambient oxygen, releasing heat. A refrigerant is particularly flammable if it falls into fire class C according to the European standard DN 2 or DIN 378 classes A2, A2L and A3 in the version most recently valid on the priority date. If a flammable refrigerant is used, the filling, shipping and operation of a cooling circuit or test chamber is made more difficult due to the safety regulations that must be observed. A major problem is a possible leak in the cooling circuit within the test chamber, which may contain electrical resistance heaters and electrically operated devices as test material. In the event of a leak, an explosion can occur.

[0004] However, in order to utilize the advantages of flammable refrigerants over non-flammable refrigerants, it is necessary to prevent a potential explosion in the test chamber in the event of a leak. As with other comparable systems, this could be achieved by means of a ventilation system that could extract escaping refrigerant from the test chamber. However, the ventilation system must be suitable for use in potentially explosive atmospheres. Such suitability refers to equipment and protective systems that comply with the ATEX directives of the European Union, in particular the ATEX Product Directive 2014 / 34 / EU and / or the ATEX Works Directive 1999 / 92 / EC in the version valid on the priority date.However, the problem here is that, depending on the test cycle, temperatures in the test chamber can range from -50 °C to +180 °C, yet ATEX-compliant fans, which would be required for a corresponding ventilation system, are not suitable for use at these temperatures. A fan specifically designed for this application, however, would not be economically viable due to the small number of units required for production and development, and the required ATEX certification.

[0005] CN 207 067 364 U discloses a test chamber, or temperature or climate chamber, with a test chamber. To monitor the test chamber atmosphere, a duct with a temperature control coil, a gas sensor, and a suction pump is connected to the test chamber. The suction pump continuously pumps air from the test chamber to the gas sensor, which, in the event of combustion gases or the like, initiates the shutdown of the power supply to the test object and the operation of the fan.

[0006] EP 2 317 254 A2 describes a refrigeration system in which, with the exception of an evaporator, all other components of a refrigeration circuit are located in a machine room. The refrigeration system operates with a hydrocarbon as the refrigerant. A gas sensor is located in the machine room, which activates a ventilation system in the event of a leak within the enclosure.

[0007] The present invention is therefore based on the object of proposing a test chamber and a method for conditioning air by means of a test chamber, with which the extraction of a test room atmosphere under explosion protection conditions is possible using simple means.

[0008] This object is achieved by a test chamber having the features of claim 1 or 6 and a method having the features of claim 18 or 20.

[0009] The test chamber according to the invention for conditioning air, in particular a temperature control chamber, climate chamber or the like, comprises a test chamber that is sealable from the environment and temperature-insulated for accommodating test material, and a temperature control device for temperature control of the test chamber, by means of which a temperature in a temperature range of -50 °C to +180 °C can be formed within the test chamber, wherein the temperature control device has a heating device and a cooling device with a cooling circuit with a refrigerant, a heat exchanger in the test chamber, a compressor, a condenser and an expansion element, wherein the refrigerant is a hydrocarbon or a refrigerant mixture of hydrocarbons, wherein the test chamber is formed with a machine room spatially separated from the test chamber, wherein the cooling circuit with the compressor is arranged at least partially in the machine room,wherein the test chamber comprises a ventilation system with a detector device with at least one gas sensor in or on the test chamber for detecting refrigerant in the test chamber, wherein the ventilation system comprises a fan and an exhaust air duct, wherein the exhaust air duct is connected to the test chamber in such a way that air can be conveyed from the test chamber into the exhaust air duct by means of the fan, wherein the fan comprises a fan motor and a fan wheel, wherein the fan motor is arranged in an airtight housing.

[0010] With the test chamber according to the invention, it is possible to safely use a hydrocarbon or a refrigerant mixture of hydrocarbons as a refrigerant in the cooling circuit and thus utilize the advantages of this type of refrigerant. During the test procedure, higher temperatures are also generated in the test chamber, whereby the air in the test chamber is then heated by the heating device. At the same time, the refrigerant contained in the heat exchanger is also heated, which leads to thermal expansion of the refrigerant in the heat exchanger. In the event of a leak, particularly in the heat exchanger in the test chamber, refrigerant can easily escape into the test chamber. Since there is regularly air in the test chamber, an explosive atmosphere can easily develop, which could, for example,in conjunction with a possibly operating electrical resistance heating element of the heating device can lead to an explosion. To prevent this, a ventilation system is provided in the test chamber which can extract air from the test space. The ventilation system comprises the detector device with the gas sensor for detecting refrigerant and / or refrigerant used in the cooling circuit. The gas sensor is arranged directly in the test space, arranged on the test space, attached to the test space or connected to the test space in such a way that if refrigerant escapes into the test space, it can be quickly detected. Furthermore, the exhaust air duct is connected to the test space so that the air from the test space can be conveyed into the exhaust air duct and thus out of the test space by means of the fan.Air from the surrounding area can flow into the test chamber through a specially designed opening in the test chamber, such as a pressure equalization device or an air supply duct. The fan itself consists of a fan motor and a fan wheel, with the fan motor being housed in an airtight enclosure. This makes it possible to use fan motors that are not ATEX-compliant. Overall, the ventilation system can be easily adapted for use under explosion-protection conditions.

[0011] The enclosure can be made of metal or sheet metal and hermetically isolate the fan motor from at least the exhaust air duct, the test chamber, and / or the machine room. Consequently, the fan can be located in the test chamber or the machine room, with the fan preferably being located in the machine room, as the fan is then not exposed to the test conditions in the test chamber. This also prevents any refrigerant escaping into the test chamber from reaching the fan motor.

[0012] The exhaust air temperature in the exhaust air duct can therefore roughly correspond to the temperature inside the test chamber. The fan motor can then be designed so that the fan can also convey hot air at temperatures as high as +180°C, for example. The airtight housing of the fan motor enables the fan motor to be shielded from hot vapors of air conveyed in the exhaust air duct or in the area of ​​the fan motor. However, the use of an ATEX-certified fan motor or fan would not be possible here, as these devices are regularly certified for a conveying medium temperature of -20°C to +60°C, which would not cover the temperature range of -50°C to +180°C reached in the test chamber.

[0013] The exhaust air duct can be connected to the test room with a first duct section and to the machine room with a second duct section, whereby the fan can be arranged in the first duct section, whereby a further fan of the ventilation system can be arranged in the further duct section. It can also be provided that refrigerant in the machine room can be detected using a further gas sensor, which is then arranged in the machine room. In this case, the further fan can then extract air from the machine room. The further duct section can be provided for this purpose, in which the further fan is then arranged. This makes it possible to extract air independently from the test room or the machine room or simultaneously from the test room and the machine room in the event of a leak in order to prevent the formation of an explosive environment.

[0014] The first duct section and the second duct section can merge into a common duct section of the exhaust air duct. The common duct section can then also run outside the test chamber, a housing of the test chamber, or the engine room. This ensures that no pressurized exhaust air ducts are located within the engine room. A potentially explosive mixture of air and refrigerant is then located in the common duct section outside the test chamber.

[0015] The additional fan can be designed for use in potentially explosive atmospheres, particularly in accordance with the ATEX Product Directive and / or the ATEX Operation Directive. Since the air temperature in the machine room is essentially the same as the ambient air temperature or only slightly higher, an ATEX-certified fan or fan motor can also be used to ventilate the machine room.

[0016] Alternatively, the test chamber according to the invention for conditioning air, in particular a temperature control chamber, climate chamber or the like, comprises a test chamber that is sealable from the environment and temperature-insulated for accommodating test material and a temperature control device for temperature control of the test chamber, by means of which a temperature in a temperature range of -50 °C to +180 °C can be formed within the test chamber, wherein the temperature control device has a heating device and a cooling device with a cooling circuit with a refrigerant, a heat exchanger in the test chamber, a compressor, a condenser and an expansion element, wherein the refrigerant is a hydrocarbon or a refrigerant mixture of hydrocarbons, wherein the test chamber is formed with a machine room spatially separated from the test chamber, wherein the cooling circuit with the compressor is arranged at least partially in the machine room,wherein the test chamber comprises a ventilation system with a detector device with at least one gas sensor for detecting refrigerant in the test chamber, wherein the ventilation system comprises a fan and an exhaust air duct, wherein the exhaust air duct is connected to the test chamber and the machine room in such a way that air can be conveyed from the machine room and the test chamber into the exhaust air duct by means of the one fan.

[0017] With the test chamber according to the invention, it is also possible to ventilate the test chamber using the ventilation system if the gas sensor in the test chamber detects a refrigerant or the refrigerant used in the cooling circuit. Since the exhaust air duct is connected to the test chamber and the machine room, air from the machine room and the test chamber is pumped into the exhaust air duct when the fan is operating. This results in a mixture of air from the test chamber and the machine room. In the machine room, the air there has a temperature that is approximately the same as the ambient air temperature or slightly higher.By mixing the air from the engine room and the air from the test room, air from the test room with a significantly different temperature, for example, -50 °C or +180 °C, can be mixed with the air from the engine room to such an extent that the air temperature in the exhaust duct is adjusted without requiring a special fan design adapted to extreme temperatures. By connecting the exhaust duct to the test room and the engine room and using a common fan for the test room and the engine room, it is therefore possible to provide air extraction under explosion-protection conditions using simple means.

[0018] The fan can be designed for use in potentially explosive atmospheres, particularly in accordance with the ATEX Product Directive and / or the ATEX Operational Directive. Since the mixture of air from the test room and the machine room in the exhaust duct allows moderate temperatures to be achieved, an ATEX-certified fan with a usable temperature range between -20 °C and +60 °C can be used. This makes the ventilation system particularly cost-effective and easy to implement.

[0019] The exhaust air duct can be connected to the test room with a first duct section and to the machine room with a second duct section, wherein the first duct section and the second duct section can open into a common duct section of the exhaust air duct, wherein the fan can be arranged in the common duct section. It can thus be provided that the first duct section and the second duct section are merged into the common duct section upstream of the fan in a flow direction. The common duct section can also lead out of a housing of the test chamber or out of the machine room immediately after the fan, so that any explosive mixture of air and refrigerant is located outside the test chamber in the common duct section.

[0020] The ventilation system can have a control valve arranged in the first duct section. The control valve makes it possible to metered mix the air volume extracted from the test room during operation of the fan with the air volume extracted from the machine room. This mixing can then be carried out in a ratio that ensures that temperatures above +60 °C and below -20 °C are not reached at the fan. The control valve can be a simple flap or aperture in the first duct section. The control valve is preferably designed so that a volume flow in the first duct section can be varied as required.

[0021] The ventilation system can have at least one sensor, which can be arranged in the first duct section, the second duct section and / or supply air duct of the ventilation system connected to the test room, wherein the sensor can be a flow sensor and / or temperature sensor. This makes it possible to determine a volume flow and / or a temperature of the air in the respective duct section. Based on the volume flow and the temperature, the air from the test room and the machine room can be mixed as needed in order to achieve a desired air temperature in the shared duct section or exhaust air duct. The ventilation system is therefore also fundamentally independent of the operation of the test chamber or the temperature control device for the test room, since the ventilation system then has specially assigned sensors.However, it would also be possible to connect the ventilation system to the temperature control device to such an extent that an air temperature of the test room, which is measured by the temperature control device, can be further processed by the ventilation system.

[0022] The test chamber can have a control device that can regulate the exhaust air temperature in the common duct section within a temperature range of -20 °C to +60 °C. The control device can be configured to ensure an appropriate mixture of air from the test chamber and air from the engine room. The mixture can be controlled by a control valve that can be controlled by the control device, whereby temperatures and / or volume flows of the respective air volumes can be determined via sensors.

[0023] The fan can advantageously be located inside the engine room. Since an ATEX-compliant fan can be used, it can also be located inside the engine room. The ventilation system can thus be largely implemented within the test chamber housing. In principle, however, it is also possible to locate the fan outside the engine room.

[0024] The ventilation system can have a supply air duct that can be connected to the test room, wherein at least one valve can be arranged in each of the supply air duct and the exhaust duct, preferably immediately upstream and downstream of the test room in a flow direction. The supply air duct can connect the test room to the surrounding area. Fresh air from the surrounding area can then flow into the test room via the supply air duct when air is extracted from the test room by the fan. To prevent air from flowing unhindered through the test room, even when no fan is in operation, valves can be arranged in each of the supply air duct and in the exhaust air duct or in a first duct section of the exhaust air duct, if one is present.

[0025] The valve can be at least one flap that can be actuated by a pressure difference. The valves can each be designed as simple flaps. The flaps can be so-called pendulum flaps, which open automatically when a pressure difference is created, for example, by the fan. For example, the flaps can be made of silicone.

[0026] The detector device can comprise at least one further gas sensor in or on the machine room, which is hermetically separated from the test room. By means of the further gas sensor, a leakage of refrigerant in the machine room can then be detected in the event of a leak in the cooling circuit within the machine room. Here, too, air can be extracted from the machine room alone or, alternatively, from the test room and the machine room simultaneously using the ventilation system. A valve box can be arranged in the machine room, in which valves of the cooling device or the cooling circuit are installed. It can be provided that the valve box is open towards the machine room in order to ensure that refrigerant escapes from the valve box if a leak should occur at this point. This leak can then also be detected by means of the further gas sensor.The gas sensor in the engine room can preferably be located on the floor of the engine room. This allows any escaping refrigerant or hydrocarbon, which is heavier than air, to sink to the floor and be reliably detected there. Any ventilation openings in the engine room or a housing of the test chamber can then be located above the floor, for example, 10 cm above the floor of the engine room, so that the escaping refrigerant cannot escape from the engine room unnoticed.

[0027] The refrigerant may be free of fluorinated hydrocarbons, flammable, and / or a single-substance refrigerant. For example, the refrigerant may be propane, ethane, ethylene, propene, isobutane, butane, or the like. The refrigerant may also be a refrigerant mixture of hydrocarbons or the aforementioned components, or a refrigerant mixture containing predominantly hydrocarbons. Furthermore, the refrigerant may be free of fluorinated hydrocarbons. This makes it possible to meet future regulatory requirements for refrigerants and avoid the disadvantages of fluorinated hydrocarbons. The refrigerant may also be suitable for generating a temperature within the test chamber within a temperature range of -40°C to +180°C, preferably -70°C to +180°C, particularly preferably -85°C to +200°C.

[0028] By means of the temperature control device, a temperature in a temperature range of -80 °C to +180 °C, preferably from -100 °C to +200 °C, can be formed within the test chamber.

[0029] In the method according to the invention for operating a test chamber for conditioning air, in particular a temperature control chamber, climate chamber or the like, the test chamber has a test space that can be closed off from the environment and is temperature-insulated for accommodating test specimens, wherein the test space is temperature-controlled by a temperature control device of the test chamber, wherein a temperature in a temperature range of -50 °C to +180 °C is formed within the test space by means of the temperature control device, wherein the temperature control device has a heating device and a cooling device with a cooling circuit with a refrigerant, a heat exchanger in the test space, a compressor, a condenser and an expansion device, wherein the refrigerant is a hydrocarbon or a refrigerant mixture of hydrocarbons, wherein the test chamber is formed with a machine room that is spatially separated from the test space,The cooling circuit with the compressor is arranged at least partially in the engine room, wherein refrigerant in the test room is detected by at least one gas sensor of a detector device of a ventilation system of the test chamber arranged in or on the test room. A fan of the ventilation system conveys air from the test room into an exhaust air duct of the ventilation system, which is connected to the test room. The fan comprises a fan motor and a fan wheel, and the fan motor is arranged in an airtight housing. Regarding the advantageous effects of the method according to the invention, reference is made to the advantageous description of the test chamber according to claim 1.

[0030] In the alternative method for operating a test chamber for conditioning air, in particular a temperature control chamber, climate chamber or the like, the test chamber has a test space that can be closed off from the environment and is temperature-insulated for accommodating test specimens, wherein the test space is temperature-controlled by a temperature control device of the test chamber, wherein a temperature in a temperature range of -50 °C to +180 °C is formed within the test space by means of the temperature control device, wherein the temperature control device has a heating device and a cooling device with a cooling circuit with a refrigerant, a heat exchanger in the test space, a compressor, a condenser and an expansion device, wherein the refrigerant is a hydrocarbon or a refrigerant mixture of hydrocarbons, wherein the test chamber is formed with a machine room that is spatially separated from the test space,The cooling circuit with the compressor is arranged at least partially in the engine room, wherein refrigerant in the test chamber is detected by at least one gas sensor of a detector device of a ventilation system of the test chamber, wherein a fan of the ventilation system conveys air from the engine room and the test chamber into an exhaust air duct of the ventilation system, which is connected to the test chamber and the engine room. For the advantageous effects of the method according to the invention, reference is made to the advantageous description of the test chamber according to claim 7.

[0031] Furthermore, the ventilation system can be operated by means of a control device in the test chamber if the detector device detects refrigerant. The test chamber can have the control device for the general control and regulation of components in the test chamber, for example the temperature control device, the heating device, the cooling device, etc. The ventilation system can then also be controlled by this control device. If the detector device detects refrigerant using the gas sensor, the control device can switch on the ventilation system immediately after the refrigerant is detected, thus triggering the extraction of air from at least the test room and / or the machine room. Optionally, the gas sensor can also be used to detect the amount of refrigerant in the air. This makes it possible to only switch on the ventilation system when there is a real risk of an explosive mixture forming.Furthermore, the control device can be used to shut down the temperature control device with the heating device and the cooling device if refrigerant is detected. This can prevent further leakage of refrigerant from the cooling circuit and / or ignition of refrigerant within the test chamber with the heating device. It can also be provided that the control device signals a malfunction if refrigerant is detected. This can be done, for example, by means of audible and / or light signals to an operator.

[0032] A control device in the test chamber can be used to perform a functional test of the ventilation system before the temperature control device can be put into operation. The functional test of the ventilation system can be carried out, for example, by starting the ventilation system's fan in such a way that the test room and / or the machine room are first ventilated. This also ensures that air from the environment of the test chamber is present in the test room or the machine room when the temperature control device is put into operation. Any gases or similar that may have previously been present there can then be removed by the ventilation system. Access to the test room, for example to work on the test specimen or to load the test specimen into the test room, can then be carried out safely for an operator.

[0033] In addition, at least one sensor can be provided in the exhaust air duct, or in a first duct section, a second duct section and / or a further duct section of the exhaust air duct, with which air movement in the exhaust air duct can be determined. The sensor can, for example, be a simple paddle switch. This at least makes it possible to carry out a simple functional test of the ventilation system. When the test chamber is switched on, the functional test of the ventilation system can then be carried out first before a main switch or relay supplies the other components of the test chamber or the temperature control device with electrical power. Likewise, the control device can be used to carry out an emergency shutdown of the test chamber or the other components if refrigerant is detected by the gas sensor and the ventilation system is put into operation.

[0034] Further advantageous embodiments of the method emerge from the descriptions of the features of the subclaims which refer back to device claims 1 and 6.

[0035] Preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawings.

[0036] They show: Fig. 1 a schematic representation of a test chamber in a sectional view; Fig. 2 a schematic representation of the test chamber in a partial perspective view; Fig. 3 a schematic representation of an embodiment of the test chamber; Fig. 4 a schematic representation of another embodiment of the test chamber.

[0037] The Fig. 1 und 2 show schematic representations of a test chamber 10 with a housing 11, within which a test space 12 and a machine room 13 are formed. In the test space 12, a heat exchanger 14 of a cooling circuit (not shown in detail here) of a temperature control device of the test chamber 10 is arranged. By means of a test space fan 15, air can be circulated within the test space 12 past the heat exchanger 14. In the machine room 13, a valve box 16 is arranged, to which valves of the cooling circuit (not shown here) are installed. The valve box 16 is open to the machine room 13. Furthermore, a condenser 17 and a compressor 18 of the cooling circuit are arranged in the machine room 13. Openings 19 and 20 for ventilating the machine room 13 are formed in the machine room 13. A gas sensor 22 of a detector device not shown here is arranged on a floor 21 of the engine room 13.Furthermore, a ventilation system 23 is provided in the machine room 13. The ventilation system 23 comprises a fan 24 and an exhaust air duct 25 connected to the test chamber 12. By means of the fan 24, air can be conveyed from the test chamber 12 into the exhaust air duct 25 if refrigerant, in particular hydrocarbon or a refrigerant mixture of hydrocarbons, is detected in the test chamber 12 or in the machine room 13 by means of a gas sensor (not shown here) in or on the test chamber 12 or by means of the gas sensor 22.

[0038] The fan 24 comprises a fan motor 26 and a fan wheel 27, wherein the fan motor 26 is arranged in an airtight housing 28. The housing 28 is made of sheet metal and arranged within the machine room 13. The ventilation system 23 can be designed as shown in Fig. 2 comprise a further fan 29, which is formed from a fan motor 30 and a fan wheel 31. The further fan 29 enables ventilation of the machine room 13. The fan motor 26 can be a conventional fan motor, which does not have to be intended for operation in potentially explosive areas. The further fan 29, on the other hand, is intended for use in potentially explosive areas. The fan 24 and the further fan 29 are connected to a common duct section 32 of the exhaust air duct 25. The common duct section 32 here runs outside the housing 11 into an environment 33. Any potentially explosive mixture of refrigerant and air is then located outside the housing 11.

[0039] The Fig. 3 shows a test chamber 34 with a test room 35 and a machine room 36. The test chamber 34 is provided with a ventilation system 37, which has an exhaust air duct 38 with a first duct section 39, a second duct section 40 and a common duct section 41. Furthermore, a gas sensor is provided in the test room 35. 42and a further gas sensor 43 is arranged in the machine room 36. The gas sensor 42 can also be arranged outside the test room 35 and connected to the test room 35, for example, via a duct. In addition, an air supply duct 44 is provided, via which air from an environment 45 can be introduced into the test room 35. Sensors 46, 47, and 48 are arranged in the first duct section 39, the second duct section 40, and the air supply duct 44. The sensors 46, 47, and 48 are flow sensors and / or temperature sensors by means of which a volume flow and / or a temperature of the air present there can be measured. In the first duct section 39, flaps 49 that can be actuated by means of a pressure difference are arranged, and flaps 50 that can also be actuated in this way are arranged in the air supply duct 44. A fan 51 is arranged in the first duct section 39, and a further fan 52 is arranged in the second duct section 40.The fan 51 has a housing 53 with which a fan motor, not shown in detail here, is hermetically shielded.

[0040] In the event of a leak in a cooling circuit (not shown in detail here) and the escape of refrigerant, which is a hydrocarbon or a refrigerant mixture of hydrocarbons, in the test chamber 35 or the machine room 36, this refrigerant can be detected by means of the gas sensors 42 and 43, respectively. The ventilation system 37, or the fan 51 and the additional fan 52, are then switched on by means of a control device of the test chamber 34 (not shown here). A control device of the control device (not shown here) can monitor the function of the fans 51 and 52, respectively, via the sensors 46, 47 and / or 48. Such a functional test can be carried out, in particular, before commissioning a temperature control device in the test chamber 34. The fan 51 and the additional fan 52 can also be operated independently of one another.In any case, the first duct section 39 and the second duct section 40 flow into the common duct section 41. The common duct section 41 then flows back into the environment 45. The flaps 49 and 50 can be made of silicone and can be actuated by a pressure difference. The test chamber 35 is then closed by the flaps 49 and 50 when the fan 51 is not in operation. The fan 51 can be a conventional fan that is not explicitly designed for use in potentially explosive atmospheres. The additional fan 52 is designed for use in potentially explosive atmospheres.

[0041] The Fig. 4shows a test chamber 54 with a test room 55 and a machine room 56 as well as a ventilation system 57. The ventilation system 57 comprises an exhaust air duct 58 with a first duct section 59, a second duct section 60 and an air supply duct 61. The first duct section 59 and the air supply duct 61 are connected to the test room 55. The second duct section 60 is connected to the machine room 56. The first duct section 59 and the second duct section 60 open into a common duct section 62 of the exhaust air duct 58. A gas sensor 63 is arranged in the test room 55 and a further gas sensor 64 is arranged in the machine room 56 for detecting refrigerant, in particular hydrocarbon or a refrigerant mixture of hydrocarbons. In the first duct section 59, the second duct section 60 and the supply air duct 61, sensors 65, 66 and 67 are also arranged, by means of which a temperature and / or an air flow ora volume flow can be detected within the duct sections 59 and 60 or the supply air duct 61. Furthermore, flaps 68 and 69 are arranged in the first duct section 59 and in the supply air duct 61, respectively. These flaps can be made of silicone, for example, and can be used to close the test chamber 55. The flaps 58 and 59 can be designed such that they open automatically when a pressure difference occurs.

[0042] A fan 70 is arranged in the common duct section 62, by means of which air can be conveyed or extracted from the test chamber 55 and the machine room 56. In particular, air from an environment 71 can flow through the supply air duct 61. The sucked-in air is blown out again into the environment 71 by the fan 70 via the common duct section 62. The ratio of the air extracted from the test chamber 55 and the machine room 56 is set or regulated by means of a control valve 72, which is arranged in the first duct section 59. The control valve 72 is controlled by means of a control device (not shown) of a control apparatus (likewise not shown) of the test chamber 54. This control is carried out using at least the sensors 65 and 66.In this case, a temperature and optionally a volume flow of the air to be conveyed in the first duct section 59 and the second duct section 60 are measured and mixed in the flow direction upstream of the fan 70 by means of the control valve 72 in such a way that the temperature at the fan 70 does not exceed or fall below a temperature range for which the fan 70 is designed. The fan 70 is designed for use in potentially explosive atmospheres, for example, for a temperature range from +60 °C to -20 °C. Only the design of the ventilation system 57 in the manner shown enables the use of the fan 70.

Claims

1. A test chamber (10, 34) for conditioning air, in particular a temperature control chamber, a climate chamber or the like, the test chamber comprising a temperature-insulated test space (12, 35), which can be sealed from an environment (33, 45) and serves to hold test material, and a temperature control device for controlling the temperature of the test space, the temperature control device having a heating feature and a cooling feature with a cooling circuit with a refrigerant, a heat exchanger (14) in the test space, a compressor (18), a condenser (17) and an expansion member, the test chamber being provided with a machine room (13, 36) physically separated from the test space, the cooling circuit with the compressor being at least partially disposed in the machine room, the temperature control device being configured to establish a temperature in a temperature range of -50 °C to +180 °C within the test space, the refrigerant being a hydrocarbon or a refrigerant mixture of hydrocarbons, the test chamber comprising a ventilation system (23, 37) having a detector with at least one gas sensor (22, 42) in or on the test space for detecting refrigerant in the test space, the ventilation system comprising a fan (24, 51) and an exhaust duct (25, 38), the exhaust duct being connected to the test space in such a manner that the fan can transport air from the test space into the exhaust duct, the fan comprising a fan motor (26) and a fan impeller (27), the fan motor being disposed in an air-tight enclosure (28, 53).

2. The test chamber according to claim 1, characterized in that the enclosure (28, 53) is made of metal or sheet metal and separates the fan motor (26) at least from the exhaust duct (25, 38), the test space (12, 35) and / or the machine room (13, 36) in an air-tight manner.

3. The test chamber according to any one of the preceding claims, characterized in that the exhaust duct (25, 38) is connected to the test space (12, 35) via a first duct section (39) and to the machine room (13, 36) via a second duct section (40), the fan (24, 51) being disposed in the first duct section, another fan (29, 52) of the ventilation system (23, 37) being disposed in the other duct section.

4. The test chamber according to claim 3, characterized in that the first duct section (39) and the second duct section (40) end in a common duct section (32, 41) of the exhaust duct (25, 38).

5. The test chamber according to claim 3 or 4, characterized in that the other fan (29, 52) is configured for use in explosive atmospheres, in particular according to the ATEX equipment directive and / or the ATEX workplace directive valid on the day of priority.

6. A test chamber (54) for conditioning air, in particular a temperature control chamber, a climate chamber or the like, the test chamber comprising a temperature-insulated test space (55), which can be sealed from an environment (71) and serves to hold test material, and a temperature control device for controlling the temperature of the test space, the temperature control device being configured to establish a temperature in a temperature range of -50 °C to +180 °C within the test space, the temperature control device having a heating feature and a cooling feature with a cooling circuit with a refrigerant, a heat exchanger in the test space, a compressor, a condenser and an expansion member, the refrigerant being a hydrocarbon or a refrigerant mixture of hydrocarbons, the test chamber being provided with a machine room (56) physically separated from the test space, the cooling circuit with the compressor being at least partially disposed in the machine room, the test chamber comprising a ventilation system (57) having a detector with at least one gas sensor (63) in the test space for detecting refrigerant in the test space, the ventilation system comprising a fan (70) and an exhaust duct (58), the exhaust duct being connected to the test space and the machine room in such a manner that the one fan can transport air from the machine room and the test space into the exhaust duct.

7. The test chamber according to claim 6, characterized in that the fan (70) is configured for use in explosive atmospheres, in particular according to the ATEX equipment directive and / or the ATEX workplace directive valid on the day of priority.

8. The test chamber according to claim 6 or 7, characterized in that the exhaust duct (58) is connected to the test space (55) via a first duct section (59) and to the machine room (56) via a second duct section (60), the first duct section and the second duct section ending in a common duct section (62) of the exhaust duct, the fan (70) being disposed in the common duct section.

9. The test chamber according to any one of claims 6 to 8, characterized in that the ventilation system (57) has an adjustment valve (72) disposed in the first duct section (59).

10. The test chamber according to any one of claims 6 to 9, characterized in that the ventilation system (57) has at least one sensor (65, 66, 67) disposed in the first duct section (59), the second duct section (60) and / or an air supply duct (61) of the ventilation system, the air supply duct being connected to the test space (55), the sensor being a flow sensor and / or a temperature sensor.

11. The test chamber according to any one of claims 6 to 10, characterized in that the test chamber (54) has a controller configured to control an exhaust air temperature in the common duct section (62) in a temperature range of -20 °C to +60 °C.

12. The test chamber according to any one of the preceding claims, characterized in that the fan (24, 51, 70) is disposed within the machine room (13, 36, 56).

13. The test chamber according to any one of the preceding claims, characterized in that the ventilation system (23, 37, 57) has an air supply duct (44, 61) connected to the test space (12, 35, 55), at least one valve being disposed both in the air supply duct and in the exhaust duct (25, 38, 58), preferably directly upstream and downstream of the test space.

14. The test chamber according to claim 13, characterized in that the valve is at least one flap (49, 50, 68, 69) operable by a difference in pressure.

15. The test chamber according to any one of the preceding claims, characterized in that the detector comprises at least one other gas sensor (43, 64) in the machine room (13, 36, 56), which is separated from the test space (12, 35, 55) in an air-tight manner.

16. The test chamber according to any one of the preceding claims, characterized in that the refrigerant is free from fluorinated hydrocarbons, is flammable and / or is a refrigerant consisting of a single substance.

17. The test chamber according to any one of the preceding claims, characterized in that the temperature control device is configured to establish a temperature in a temperature range of -80 °C to +180 °C, preferably -100 °C to +200 °C, within the test space (12, 35, 55).

18. A method for operating a test chamber (10, 34) for conditioning air, in particular a temperature control chamber, a climate chamber or the like, the test chamber having a temperature-insulated test space (12, 35), which can be sealed from an environment (33, 45) and serves to hold test material, the test space being temperature-controlled using a temperature control device of the test chamber, the temperature control device having a heating feature and a cooling feature with a cooling circuit with a refrigerant, a heat exchanger (14) in the test space, a compressor (18), a condenser (17) and an expansion member, the test chamber being provided with a machine room (13, 36) physically separated from the test space, the cooling circuit with the compressor being at least partially disposed in the machine room, the temperature control device being used to establish a temperature in a temperature range of -50 °C to +180 °C within the test space, the refrigerant being a hydrocarbon or a refrigerant mixture of hydrocarbons, refrigerant in the test space being detected using at least one gas sensor (22, 42) of a detector of a ventilation system (23, 37) of the test chamber, the gas sensor being disposed in or on the test space, a fan (24, 51) of the ventilation system being used to transport air from the test space into an exhaust duct (25, 38) of the ventilation system, the exhaust duct being connected to the test space, the fan comprising a fan motor (26) and a fan impeller (27), the fan motor being disposed in an air-tight enclosure (28, 53).

19. The method according to claim 18, characterized in that an exhaust air temperature in the exhaust duct (25, 38) approximately corresponds to the temperature within the test space (12, 35)20. A method for operating a test chamber (54) for conditioning air, in particular a temperature control chamber, a climate chamber or the like, the test chamber having a temperature-insulated test space (55), which can be sealed from an environment (71) and serves to hold test material, the test space being temperature-controlled using a temperature control device of the test chamber, the temperature control device being used to establish a temperature in a temperature range of -50 °C to +180 °C within the test space, the temperature control device having a heating feature and a cooling feature with a cooling circuit with a refrigerant, a heat exchanger in the test space, a compressor, a condenser and an expansion member, the refrigerant being a hydrocarbon or a refrigerant mixture of hydrocarbons, the test chamber being provided with a machine room (56) physically separated from the test space, the cooling circuit with the compressor being at least partially disposed in the machine room, refrigerant in the test space being detected using at least one gas sensor (63) of a detector of a ventilation system (57) of the test chamber, the gas sensor being disposed in the test space, a fan (70) of the ventilation system being used to transport air from the machine room and the test space into an exhaust duct (58) of the ventilation system, the exhaust duct being connected to the test space and the machine room.

21. The method according to claim 19 or 20, characterized in that a controller of the test chamber (10, 34, 54) is used to operate the ventilation system (23, 37, 57) when the detector detects refrigerant.

22. The method according to any one of claims 19 to 21, characterized in that a controller of the test chamber (10, 34, 54) is used to test a function of the ventilation system (23, 37, 57) before the temperature control device is put into operation.