Online continuous cooling and separating device for high-temperature gas

Abstract

The utility model provides an online continuous cooling and separating device for high-temperature gas. The online continuous cooling and separating device comprises a shell, a metal framework, a first cooling device, a powder collecting device and a gas collecting device, the shell is arranged outside the first cooling device in a sleeving manner, and the metal framework is arranged in the first cooling device in a sleeving manner; the powder collecting device is arranged in the metal framework in a sleeved mode. The powder collecting device is detachably connected with the shell; the gas collecting device comprises a pump, a gas conveying pipeline and a gas collecting pipeline; the pump is positioned outside the shell; the gas collecting pipeline is partially or completely located in the shell, and the gas collecting pipeline is connected with the pump through the gas conveying pipeline; the mixed gas is cooled and separated, the temperature of the mixed gas is reduced to 100 DEG C or below, dust in the mixed gas and powder generated after cooling are separated from the gas, and the separated pure gas is conveyed.

Description

Technical Field

[0001] The utility model relates to the technical field of separation devices, and more specifically, to a field of high-temperature gas on-line continuous cooling and separation devices. Background Art

[0002] When producing zinc selenide using the chemical vapor deposition process, the product quality is high, but the excess mixed gas discharged during the production process has the following characteristics: there is dust generated by the solidification of metal vapor in the mixed gas, and some types of gases will undergo reversible decomposition reactions above 160°C to form solid decomposition products; the mixed gas has a high temperature, above 400°C; the mixed gas has a large flow rate, a high concentration of easily decomposable gases, and a large amount of solid decomposition products; the mixed gas is a toxic and dangerous gas, and is flammable and explosive;

[0003] The above characteristics of the mixed gas cause the following impacts on production when the mixed gas is directly transported: 1. The solid products formed by the solidification of metal vapor and the decomposition of toxic gases accumulate in the pipeline, affecting the pipeline smoothness; 2. When the high-temperature mixed gas is pumped away by the power pump, it will heat the pump body, resulting in the loss of pump oil. 3. The decomposition products enter the power pump, and the pump oil is contaminated, making the oil unable to be recycled and reused, and it is easy to have a pump jamming accident, causing the process to be interrupted and forced to stop production. 4. After the solid decomposition products are mixed with the pump oil and enter the recovery device, not only the recovery device is contaminated, but it is extremely difficult to handle.

[0004] Therefore, how to separate the dust and easily decomposable gases in the mixed gas while cooling it, and then transport and collect the separated gas has become an urgent problem to be solved in this field. Summary of the Utility Model

[0005] In order to solve the above technical problems, the purpose of the utility model is to provide a high-temperature gas on-line continuous cooling and separation device, which cools and separates the mixed gas, reduces the temperature of the mixed gas to below 100°C, separates the dust in the mixed gas and the powder generated after cooling from the gas, and transports the separated pure gas.

[0006] The utility model provides a high-temperature gas on-line continuous cooling and separation device, including a shell, a metal framework, a first cooling device, a powder collection device, and a gas collection device;

[0007] The shell is sleeved outside the first cooling device, and the metal framework is sleeved inside the first cooling device;

[0008] The powder collection device is sleeved inside the metal framework; the powder collection device is provided with a powder collection device air inlet, and the high-temperature gas enters the powder collection device through the powder collection device air inlet;

[0009] The gas collection device includes a pump, a gas delivery pipeline, and a gas collection pipeline; the pump is located outside the housing; part or all of the gas collection pipeline is located inside the housing, and the gas collection pipeline is connected to the pump through the gas delivery pipeline; preferably, a gas inlet is provided at the connection end of the powder collection device and the housing. The mixed gas entering the powder collection device is cooled, and the powder remains in the powder collection device, while the gas is drawn out of the powder collection device by negative pressure and collected through the pipeline.

[0010] The beneficial effect of the previous step is that the first cooling device is fixed outside the metal framework through the metal framework; by sleeving the powder collection device inside the metal framework, when the mixed gas enters the powder collection device, the mixed gas in the powder collection device is cooled by the first cooling device fixed outside the metal framework.

[0011] The cooled and filtered gas is collected and transported to a designated position by the gas collection device; the pump provides power for the directional flow of the mixed gas from the inlet to the powder collection device in the powder collection device, which is beneficial to the extraction of gas from the powder collection device; since the pump is located outside the housing, the gas in direct contact with the gas collection device is the gas that has been cooled and filtered, thus avoiding the accumulation of warm solidification products and solid products obtained by decomposing toxic gases in the pipeline of the gas collection device, which affects the pipeline smoothness; at the same time, it avoids the problem that the high-temperature mixed gas heats the pump body when being pumped away by the power pump, resulting in the loss of pump oil; it avoids the problem that some decomposition products in the mixed gas enter the pump body and contaminate the pump oil.

[0012] Only the powder collection device in the whole device is in contact with the mixed gas, thus avoiding problems such as blockage or damage to the equipment and pipelines caused by the high temperature of the mixed gas and the gases in it that are prone to react and become powder. The powder collection device is detachably connected to the housing, and the powder collected in the powder collection device can be regularly collected, and the powder collection device can be cleaned, so as to realize normal production.

[0013] Furthermore, the first cooling device includes a first cold source and a first spiral metal coil pipe.

[0014] The first spiral metal coil pipe is spirally wound around the outer surface of the metal framework.

[0015] The liquid inlet end of the first spiral metal coil pipe passes through the housing and is connected to the first cold source; the liquid outlet end of the first spiral metal coil pipe passes through the housing and is connected to the first cold source circulation device; preferably, the first cold source is cooling circulating water or refrigerant; the temperature of the cold source is 3 - 10°C; preferably, the liquid inlet end of the first spiral metal coil pipe is close to the gas inlet of the powder collection device.

[0016] Further, the pitches of the first spiral metal coiled pipe are different, and the pitch of the first spiral metal coiled pipe gradually increases from the end close to the air inlet of the powder collection device to the end far from the air inlet of the powder collection device;

[0017] Preferably, the pitch of the first spiral metal coiled pipe close to the air inlet of the powder collection device is 8 - 12 cm, and the pitch of the first spiral metal coiled pipe far from the air inlet of the powder collection device is 1.8 - 3.4 cm.

[0018] The beneficial effect of the previous step is that by gradually increasing the pitch of the first spiral metal coiled pipe from the end close to the air inlet of the powder collection device to the end far from the air inlet of the powder collection device, it is beneficial to achieve that the cooling temperature of the mixed gas gradually decreases as it moves further away from the air inlet, that is, to achieve good cooling effect while avoiding waste of the refrigerant.

[0019] Further, the first spiral metal coiled pipe is provided with a plurality of support members. One end of the support member is connected to the outer wall of the metal pipe, and the other end is in contact with the adjacent metal pipe to support the adjacent metal pipe.

[0020] Further, the support member includes a fixed end and a support end. The fixed end is provided with an internal thread hole, and the support end is provided with an external thread matching the internal thread hole of the fixed end. The fixed end and the support end are connected by threads;

[0021] The end of the support end far from the fixed end is provided with a groove.

[0022] The beneficial effect of the previous step is that by providing a plurality of support members on the first spiral metal coiled pipe, deformation of the first spiral metal coiled pipe is avoided.

[0023] Further, one end of the housing is provided with a connection disk, and the connection disk is provided with a plurality of threaded holes;

[0024] One end of the powder collection device close to the air inlet of the powder collection device is provided with a plurality of fixing holes, and the fixing holes are connected to the threaded holes of the connection disk through bolts;

[0025] Preferably, the powder collection device is a cloth bag.

[0026] The beneficial effect of the previous step is that by providing a plurality of threaded holes on the connection disk and connecting the fixing holes to the threaded holes of the connection disk through bolts, the powder collection device and the housing are detachably connected;

[0027] By using the powder collection device as a cloth bag, it is possible to collect the filtered powder and at the same time facilitate disassembly and replacement.

[0028] Further, a powder collection and support device is provided at one end of the metal framework close to the gas collection device. The powder collection and support device includes a plate-shaped metal mesh, and the plate-shaped metal mesh is connected to the inner wall of the housing or the metal framework. A first accommodation space with one end open is formed between the metal framework and the plate-shaped metal mesh. The main body of the powder collection device is located in the first accommodation space, and one end of the powder collection device away from the air inlet of the powder collection device contacts the plate-shaped metal mesh.

[0029] The beneficial effect of the previous step is that through the plate-shaped metal mesh, it is beneficial to support the powder collection device, avoid the problem that the powder collection device is damaged when too much powder is collected in the powder collection device, and the setting of the plate-shaped metal mesh does not affect the gas collection device to collect the filtered gas.

[0030] Further, part or all of the gas collection pipeline is located between the plate-shaped metal mesh and the bottom of the housing. A vibration device is connected to the housing or the metal framework.

[0031] The vibration device includes an electric motor, a transmission device, and a vibrating member. The vibrating member is connected to the electric motor through the transmission device, and the vibrating member contacts the plate-shaped metal mesh.

[0032] The beneficial effect of the previous step is that the filtered gas enters the gas transmission pipeline through the gas collection pipeline through the gas transmission pipeline.

[0033] Through the vibration device, it is beneficial to shed the powder on the surface of the powder collection device from the surface of the powder collection device, avoid the surface of the powder collection device being covered by the collected powder, resulting in the gas being unable to pass through the powder collection device, and thus the gas being unable to be filtered and collected.

[0034] Further, the gas collection device includes a powder filtration device. The powder filtration device is located inside the housing and outside the metal framework. The powder filtration device is connected to the gas collection pipe. Preferably, the powder filtration device includes a filter bag with one end open and a spiral support bar connected to the inside of the filter bag.

[0035] The beneficial effect of the previous step is that the powder remaining in the gas after cooling and filtering by the powder collection device is filtered again in the powder filtration device to avoid the remaining powder in the gas entering the gas collection device. Through the spiral support bar connected to the inside of the filter bag, it is ensured that the filter bag will not be deformed during operation, resulting in the blockage of the gas outlet.

[0036] Further, the high-temperature gas on-line continuous cooling and separation device is characterized in that it further includes a second cooling device, and the second cooling device is sleeved inside the powder collection device.

[0037] The second cooling device includes a second cold source, a second spiral metal coil pipe, and a flat coil pipe. A number of air outlets are provided on the pipe wall of the second spiral metal coil pipe and the pipe wall of the flat coil pipe;

[0038] The second spiral metal coil pipe is sleeved inside and in contact with the powder collection device, and the flat coil pipe is in contact with the bottom of the powder collection device;

[0039] The air inlet pipe orifice of the flat coil pipe passes through the air inlet of the powder collection device and is connected to the second cold source. One end of the second spiral metal coil pipe is closed, and the other end is connected to the air outlet pipe orifice of the flat coil pipe;

[0040] The second cold source is cold air, and the temperature of the second cold source is 5 - 20 °C; preferably, the second cooling device further includes a second cooling device connection part. The second cooling device connection part is provided with fixing holes, and the fixing holes are connected to the threaded holes of the connection plate through bolts to realize the detachable connection of the second cooling device and the housing; preferably, the outer surfaces of the second spiral metal coil pipe and the flat coil pipe are coated with a protective layer, and the protective layer is provided with protective layer air outlets that communicate with the air outlets on the pipe walls of the second spiral metal coil pipe and the flat coil pipe; the protective layer is made of polytetrafluoroethylene.

[0041] The beneficial effect of the previous step is that by sleeving the second cooling device inside the powder collection device, the cooling of the mixed gas entering the powder collection device is realized, and at the same time, it is beneficial to keep the shape of the powder collection device from changing significantly; by providing a number of air outlets on the pipe walls of the second spiral metal coil pipe and the flat coil pipe, the cooling gas enters the powder collection device through the air outlets to cool the mixed gas, and at the same time, it is beneficial to blow the powder attached to the surface of the powder collection device away from the surface of the powder collection device, thus further helping to avoid the problem that the gas cannot come out of the powder collection device due to the surface of the powder collection device being covered with powder;

[0042] By connecting the air inlet pipe orifice of the flat coil pipe through the air inlet of the powder collection device to the second cold source, and closing one end of the second spiral metal coil pipe and connecting the other end to the air outlet pipe orifice of the flat coil pipe, the problem that the resistance of the mixed gas entering the powder collection device increases due to the relatively high air pressure near the air inlet of the powder collection device is avoided; therefore, through the second cooling device, the quality of the cooling and filtering of the mixed gas is improved, and at the same time, the efficiency of the cooling and filtering of the mixed gas is also improved;

[0043] The outer surfaces of the second spiral metal coil pipe and the planar coil pipe are coated with a protective layer, and the protective layer is made of polytetrafluoroethylene, which helps to avoid the problem of dust accumulation on the surfaces of the second spiral metal coil pipe and the planar coil pipe. Even if a small amount of dust adheres to the surface of the protective layer, it is very easy to blow off the dust by blowing compressed air again from the air inlet of the powder collection device during shutdown. Description of the Drawings

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments of the present invention will be described below.

[0045] Figure 1 It is a schematic structural diagram of the high-temperature gas on-line continuous cooling and separation device according to Embodiment 1 of the present invention;

[0046] Figure 2 It is a top view of the housing, the first spiral metal coil pipe, the metal skeleton, and the powder collection device according to Embodiment 1 of the present invention;

[0047] Figure 3 It is a schematic structural diagram of the high-temperature gas on-line continuous cooling and separation device according to Embodiment 2 of the present invention;

[0048] Figure 4 It is a top view of the housing, the first spiral metal coil pipe, the metal skeleton, the powder collection device, the second spiral metal coil pipe, and the planar coil pipe according to Embodiment 2 of the present invention.

[0049] Reference numerals shown in the drawings: 1, housing; 2, first spiral metal coil pipe; 3, metal skeleton; 4, powder collection device; 5, gas collection pipeline; 6, plate-shaped metal mesh; 7, threaded hole; 8, vibrating member; 9, pump; 10, second spiral metal coil pipe; 11, liquid inlet end of the first spiral metal coil pipe; 12, liquid outlet end of the first spiral metal coil pipe; 13, air inlet of the powder collection device; 14, planar coil pipe; 15, air inlet of the planar coil pipe. Detailed Description of the Embodiments

[0050] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will detail various aspects related to the present invention in conjunction with specific embodiments. However, these specific embodiments are only used to illustrate the present invention and do not constitute any limitation to the protection scope and essential content of the present invention.

[0051] Example 1:

[0052] This embodiment provides a high-temperature gas on-line continuous cooling and separation device, including a housing 1, a metal skeleton 3, a first cooling device, a powder collection device 4, and a gas collection device;

[0053] The housing 1 is sleeved outside the first cooling device, and the metal framework 3 is sleeved inside the first cooling device; the powder collection device 4 is sleeved inside the metal framework 3; the powder collection device 4 is provided with a powder collection device air inlet 13, and high-temperature gas enters the powder collection device 4 through the powder collection device air inlet 13; the powder collection device 4 is a cloth bag.

[0054] The first cooling device includes a first cold source and a first spiral metal coil 2; the first spiral metal coil 2 is spirally wound around the outer surface of the metal framework 3.

[0055] The liquid inlet end 11 of the first spiral metal coil passes through the housing 1 and is connected to the first cold source; the liquid outlet end 12 of the first spiral metal coil passes through the housing 1 and is connected to the first cold source circulation device; the first cold source is cooling circulating water or a refrigerant; the temperature of the cold source is 6°C; the liquid inlet end 11 of the first spiral metal coil is close to one end of the powder collection device air inlet 13.

[0056] The pitches of the first spiral metal coil 2 are different, and the pitch of the first spiral metal coil 2 gradually increases from the end close to the powder collection device air inlet 13 to the end far from the powder collection device air inlet 13.

[0057] The pitch of the first spiral metal coil 2 close to the powder collection device air inlet 13 is 8 - 12 cm; the pitch of the first spiral metal coil 2 far from the powder collection device air inlet 13 is 1.8 - 3.4 cm.

[0058] The first spiral metal coil 2 is provided with a plurality of support members. One end of the support member is connected to the outer wall of the metal tube, and the other end is in contact with the adjacent metal tube to support the adjacent metal tube; the support member includes a fixed end and a support end. The fixed end is provided with an internal thread hole, and the support end is provided with an external thread matching the internal thread hole of the fixed end. The fixed end and the support end are connected by threads; a groove is provided at the end of the support end far from the fixed end.

[0059] One end of the metal framework 3 close to the gas collection device is provided with a powder collection support device. The powder collection support device includes a plate-shaped metal mesh 6, and the plate-shaped metal mesh 6 is connected to the inner wall of the housing 1 or the metal framework 3; a first accommodation space with one end open is formed between the metal framework 3 and the plate-shaped metal mesh 6. The main body of the powder collection device 4 is located in the first accommodation space, and the end of the powder collection device 4 far from the powder collection device air inlet 13 is in contact with the plate-shaped metal mesh 6.

[0060] The powder collection device 4 is detachably connected to the housing 1; the gas collection device is connected to the housing 1 through a gas collection pipe; one end of the housing 1 is provided with a connection disk, and the connection disk is provided with a plurality of threaded holes 7.

[0061] One end of the powder collection device 4 close to the air inlet 13 of the powder collection device is provided with a plurality of fixing holes, and the fixing holes are connected to the threaded holes 7 of the connecting plate through bolts.

[0062] The gas collection device includes a pump 9, a gas delivery pipeline, and a gas collection pipeline 5; the pump 9 is located outside the housing 1; part or all of the gas collection pipeline 5 is located inside the housing 1, and the gas collection pipeline 5 is connected to the pump 9 through the gas delivery pipeline; part of the gas collection pipeline 5 is located between the plate-shaped metal mesh 6 and the bottom of the housing 1; the housing 1 is connected with a vibration device;

[0063] The vibration device includes an electric motor, a transmission device, and a vibration member 8. The vibration member 8 is connected to the electric motor through the transmission device, and the vibration member 8 contacts the plate-shaped metal mesh 6.

[0064] The connection end of the powder collection device 4 and the housing 1 is provided with a gas inlet. For the mixed gas entering the powder collection device 4, after cooling, the powder remains in the powder collection device 4, and the gas is drawn outside the powder collection device 4 by negative pressure and collected through a pipeline.

[0065] Example 2:

[0066] The content identical to that in the first embodiment will not be elaborated here; this embodiment provides a high-temperature gas on-line continuous cooling and separation device, which further includes a second cooling device sleeved inside the powder collection device 4;

[0067] The second cooling device includes a second cold source, a second spiral metal coil 10, and a flat coil 14. A plurality of air outlets are provided on the tube walls of the second spiral metal coil 10 and the flat coil 14; a protective layer is coated on the outer surfaces of the second spiral metal coil 10 and the flat coil 14, and the protective layer is provided with protective layer air outlets communicating with the air outlets on the tube walls of the second spiral metal coil 10 and the flat coil 14; the protective layer is made of polytetrafluoroethylene;

[0068] The second spiral metal coil 10 is sleeved inside the powder collection device 4, and the flat coil 14 contacts the bottom of the powder collection device 4;

[0069] The air inlet pipe 15 of the flat coil passes through the air inlet 13 of the powder collection device and is connected to the second cold source. One end of the second spiral metal coil 10 is closed, and the other end is connected to the air outlet pipe of the flat coil 14; the second cooling device further includes a second cooling device connection part, and the second cooling device connection part is provided with fixing holes, and the fixing holes are connected to the threaded holes 7 of the connecting plate through bolts to realize the detachable connection of the second cooling device and the housing.

[0070] The second cold source is cold air, and the temperature of the second cold source is 18°C.

[0071] The first cold source is cooling circulating water or refrigerant liquid; the temperature of the cold source is 8°C.

[0072] Example 3:

[0073] The content that is the same as that in Embodiment 1 in this embodiment will not be elaborated; this embodiment provides a high-temperature gas on-line continuous cooling and separation device. The gas collection device further includes a powder filtration device. The powder filtration device is located in the housing 1 and outside the metal framework 3; the powder filtration device is connected to the gas collection pipe; preferably, the powder filtration device includes a filter bag with one end open and a spiral support strip connected to the inside of the filter bag.

[0074] The first cold source is cooling circulating water or refrigerant liquid; the temperature of the cold source is 4°C.

[0075] The present invention has been described in conjunction with specific embodiments. These specific embodiments are merely exemplary and cannot be used to limit the protection scope of the present invention. Those skilled in the art can make various modifications, changes or substitutions without departing from the essence of the present invention. Therefore, all equivalent changes made according to the present invention still fall within the scope covered by the present invention.

Claims

1. An on-line continuous cooling and separation device for high-temperature gas, characterized in that, It includes a housing, a metal skeleton, a first cooling device, a powder collection device, and a gas collection device; The housing is sleeved outside the first cooling device, and the metal skeleton is sleeved inside the first cooling device; The powder collection device is sleeved inside the metal skeleton; the powder collection device is provided with a powder collection device air inlet, and high-temperature gas enters the powder collection device through the powder collection device air inlet; The powder collection device is detachably connected to the housing; the gas collection device includes a pump, a gas delivery pipeline, and a gas collection pipeline; the pump is located outside the housing; a part or all of the gas collection pipeline is located inside the housing, and the gas collection pipeline is connected to the pump through the gas delivery pipeline.

2. The high-temperature gas on-line continuous cooling and separation device according to claim 1, wherein The first cooling device includes a first cold source and a first spiral metal coil; The first spiral metal coil is spirally wound around the outer surface of the metal skeleton; The liquid inlet end of the first spiral metal coil passes through the housing and is connected to the first cold source; the liquid outlet end of the first spiral metal coil passes through the housing and is connected to the first cold source circulation device.

3. The high-temperature gas on-line continuous cooling and separation device according to claim 2, wherein, The pitches of the first spiral metal coil are different, and the pitch of the first spiral metal coil gradually increases from the end close to the powder collection device air inlet to the end far from the powder collection device air inlet.

4. The high-temperature gas on-line continuous cooling and separation device according to claim 1, characterized in that, The first spiral metal coil is provided with a plurality of support members, one end of each support member is connected to the outer wall of the metal pipe, and the other end is in contact with the adjacent metal pipe to support the adjacent metal pipe.

5. The on-line continuous cooling and separation device for high-temperature gas according to claim 4, characterized in that The support member includes a fixed end and a support end, the fixed end is provided with an internal thread hole, the support end is provided with an external thread matching the internal thread hole of the fixed end, and the fixed end and the support end are connected by threads; The end of the support end far from the fixed end is provided with a groove.

6. The on-line continuous cooling and separation device for high-temperature gas according to claim 1, characterized in that, One end of the housing is provided with a connection plate, and the connection plate is provided with a plurality of threaded holes; One end of the powder collection device close to the powder collection device air inlet is provided with a plurality of fixing holes, and the fixing holes are connected to the threaded holes of the connection plate through bolts.

7. The high-temperature gas on-line continuous cooling and separation device according to claim 1, characterized in that, One end of the metal skeleton close to the gas collection device is provided with a powder collection support device, the powder collection support device includes a plate-shaped metal mesh, and the plate-shaped metal mesh is connected to the inner wall of the housing or the metal skeleton; a first accommodation space with one end open is formed between the metal skeleton and the plate-shaped metal mesh, the main body of the powder collection device is located in the first accommodation space, and one end of the powder collection device far from the powder collection device air inlet is in contact with the plate-shaped metal mesh.

8. The on-line continuous cooling and separation device for high-temperature gas according to claim 7, wherein A part or all of the gas collection pipeline is located between the plate-shaped metal mesh and the bottom of the housing; the housing or the metal skeleton is connected with a vibration device; The vibration device includes an electric motor, a transmission device, and a vibration member, the vibration member is connected to the electric motor through the transmission device, and the vibration member is in contact with the plate-shaped metal mesh.

9. The on-line continuous cooling and separation device for high-temperature gas according to claim 7, wherein, The gas collection device further includes a powder filtering device, the powder filtering device is located inside the housing and outside the metal skeleton; the powder filtering device is connected to the gas collection pipe.

10. The high-temperature gas on-line continuous cooling and separation device according to claim 9, characterized in that, The powder filtering device includes a filter bag with one end open and a spiral support strip connected to the inside of the filter bag.

11. The on-line continuous cooling and separation device for high-temperature gas according to claim 6, characterized in that, It further includes a second cooling device, and the second cooling device is sleeved inside the powder collection device; The second cooling device includes a second cold source, a second spiral metal coil, and a flat coil. A plurality of air outlets are provided on the tube walls of the second spiral metal coil and the flat coil. The second spiral metal coil is sleeved inside the powder collection device, and the flat coil is in contact with the bottom of the powder collection device. The air inlet of the flat coil passes through the air inlet of the powder collection device and is connected to the second cold source. One end of the second spiral metal coil is closed, and the other end is connected to the air outlet of the flat coil. The second cold source is cold air, and the temperature of the second cold source is 5-20°C.

Images