Gas Replacement Cylinder Constant Temperature System and Temperature Control Method

Abstract

This invention discloses a constant-temperature system and temperature control method for gas-replacement cylinders. The constant-temperature system for gas-replacement cylinders includes a steam control unit, a heat exchange unit, and a condensate draining unit. The steam control unit includes a steam header and a pressure control valve and a temperature control valve installed on the steam header. The heat exchange unit includes a cylinder heating chamber and a condenser. The cylinder heating chamber contains multiple gas cylinders. The steam header is connected to the cylinder heating chamber, and the cylinder heating chamber is connected to the condenser. The condensate draining unit includes a condensate draining header, multiple first condensate drain pipes, and a butterfly valve, a fan, and a check valve installed on the first condensate drain pipes. The condenser is connected to the condensate draining header via the first condensate drain pipes. Using hot steam as a heat source to maintain a constant temperature for the gas cylinder body solves the problems of requiring full manual intervention and the passive nature of manual pouring of gas into the cylinders in related technologies, and effectively avoids the safety hazards of electric heating methods for hydrogen systems.

Description

Technical Field

[0001] This invention relates to the field of gas replacement technology, and in particular to a constant-temperature system and temperature control method for gas replacement cylinders. Background Technology

[0002] Large thermal power generator sets generally use hydrogen as a cooling medium. However, hydrogen is a flammable and explosive gas. Before and after long-term shutdown or maintenance of the generator, intermediate media such as carbon dioxide or nitrogen are needed to replace the gas inside the generator.

[0003] Cylinder gas is widely used in power generation companies as a preferred product. However, during the process of replacing the gas inside the machine with cylinder gas, the high-pressure liquid gas inside the cylinder needs to continuously absorb heat from the surrounding air to release heat and condense into frost or even ice on the cylinder body. This seriously hinders the efficiency and speed of the gas conversion from liquid to gas, and may even affect the gas replacement work inside the machine.

[0004] In related technologies, most methods involve heating the cylinders by pouring large amounts of cold water over them or by laying electric heating blankets on their surfaces. However, pouring cold water over them is not only inefficient but also requires manual intervention throughout the process. Large amounts of water flowing onto the ground can also negatively impact the surrounding environment and civilized production. Laying electric heating blankets can pose safety hazards to the generator's hydrogen system. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] Therefore, embodiments of the present invention propose a gas replacement cylinder constant heat system, which uses hot steam as a heat source to heat the cylinder body, and has the characteristics of safety, high efficiency and flexible handling.

[0007] Embodiments of the present invention also propose a temperature control method for the above-mentioned gas displacement cylinder constant temperature system.

[0008] The gas replacement cylinder constant temperature system of this invention includes: a steam control unit, a heat exchange unit, and a condensate venting unit. The steam control unit includes a steam header and a pressure control valve and a temperature control valve sequentially arranged on the steam header from upstream to downstream. The heat exchange unit includes a cylinder heating box and a condenser. The cylinder heating box contains multiple gas cylinders and has a first steam input end and a first steam output end. The output end of the steam header is connected to the first steam input end. The condenser has a second steam input end and a second steam output end. The first steam output end is connected to the second steam input end via a pipeline. The pressure probe of the pressure control valve is located on the gas inlet pipeline of the gas replacement system. The temperature probe of the temperature control valve is located inside the cylinder heating box. The condensate venting unit includes a venting header, multiple first vent pipes, and a butterfly valve, a fan, and a check valve sequentially arranged on the first vent pipes from upstream to downstream. The input end of the first vent pipe is connected to the second steam output end, and the output end of the first vent pipe is connected to the venting header.

[0009] In the gas replacement cylinder constant temperature system of this invention, hot steam enters the heat exchange unit under the control of the steam control unit, and the exhaust steam after heat exchange is completed is discharged from the system through the condensate venting unit. Using hot steam as a heat source to heat the cylinder body at a constant temperature solves the problems of inefficiency and impact on civilized production caused by using cold water to spray the cylinder in related technologies. It also effectively avoids the risks of electric shock and safety hazards associated with heating the cylinder by applying electric heating blankets to the cylinder surface or placing the cylinder in an electric heating box (with several electric heating rods inside the box to indirectly heat the cylinder body by raising the temperature of the air inside the box).

[0010] In some embodiments, the steam control unit further includes a pressure reducing valve and a throttling device, the pressure reducing valve being disposed on the steam header and upstream of the pressure control valve, and the throttling device being disposed inside the steam header and downstream of the temperature control valve.

[0011] In some embodiments, the steam control unit further includes a shut-off valve and a gate valve, both of which are located on the steam header. The shut-off valve is located upstream of the pressure reducing valve, and the gate valve is located downstream of the temperature control valve and upstream of the throttling device.

[0012] In some embodiments, the steam control unit further includes a steam sub-pipe and a first normally closed gate valve disposed on the steam sub-pipe, the input end of the steam sub-pipe being connected to the steam main pipe located between the pressure reducing valve and the pressure control valve, and the output end of the steam sub-pipe being connected to the steam main pipe located between the gate valve and the throttling device.

[0013] In some embodiments, the condensate venting unit further includes a direct venting pipe and a normally closed shut-off valve disposed on the direct venting pipe. The input end of the direct venting pipe is connected to the steam header located between the pressure reducing valve and the input end of the steam sub-pipe. The output end of the direct venting pipe is provided with a first funnel.

[0014] In some embodiments, the cylinder heating box is further provided with a first condensate drain, the condenser is further provided with a second condensate drain, and the condensate venting unit further includes a first U-shaped water seal and a second funnel connected together, the first condensate drain and the second condensate drain being connected to the first U-shaped water seal via pipelines.

[0015] In some embodiments, the hydrophobic venting unit further includes a second U-shaped water seal and a third funnel connected together, and the venting header is connected to the second U-shaped water seal.

[0016] In some embodiments, the condensate venting unit further includes a second venting pipe and a second normally closed gate valve disposed on the second venting pipe. The input end of the second venting pipe is connected to the second steam output end, and the output end of the second venting pipe is connected to the venting header.

[0017] The temperature control method of this invention, used in the gas replacement cylinder constant temperature system described in any of the above embodiments, includes:

[0018] When the temperature T measured by the temperature probe of the temperature control valve is higher than the temperature set value T0, the opening degree of the temperature control valve is reduced.

[0019] When the temperature T measured by the temperature probe of the temperature control valve is lower than the temperature set value T0, the opening of the temperature control valve is increased to maintain the temperature inside the cylinder heating box within the temperature set value T0.

[0020] When the temperature T measured by the temperature probe of the temperature control valve reaches T1, the temperature control valve is closed.

[0021] When the pressure probe of the pressure control valve measures that the pressure in the gas replacement system’s inlet pipe reaches or falls below the minimum allowable pressure P of the gas cylinder, or when the temperature probe of the temperature control valve measures that the temperature reaches T1 and the temperature has not dropped after 10 seconds, the pressure control valve is closed.

[0022] The temperature setting value T0 has a parameter range of 35 to 40°C, T1 has a temperature of 40°C, and the minimum allowable pressure P of the gas cylinder is 0.1 MPa.

[0023] In some embodiments, when the temperature control valve and the pressure control valve are closed simultaneously, the fan is stopped after a 20-second delay. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the gas replacement cylinder constant temperature system according to an embodiment of the present invention.

[0025] Figure 2 This is a logic diagram of the temperature control method according to an embodiment of the present invention.

[0026] Figure label:

[0027] Steam header 11, pressure control valve 111, temperature control valve 112, pressure reducing valve 113, throttling device 114, shut-off valve 115, gate valve 116, steam sub-pipe 12, first normally closed gate valve 121

[0028] Cylinder heating box 21, condenser 22

[0029] Steam exhaust header 31, first steam exhaust pipe 32, butterfly valve 321, blower 322, check valve 323, straight exhaust pipe 33, normally closed stop valve 331, first funnel 34, first U-shaped water seal 35, second funnel 36, second U-shaped water seal 37, third funnel 38, second steam exhaust pipe 39, second normally closed gate valve 391. Detailed Implementation

[0030] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0031] The gas replacement cylinder constant temperature system of the present invention is described below with reference to the accompanying drawings.

[0032] like Figure 1 As shown, the gas replacement cylinder constant temperature system of this invention includes: a steam control unit, a heat exchange unit, and a condensate venting unit.

[0033] It should be understood that the upstream and downstream are defined by the flow direction of the hot steam. The steam control unit includes a steam header 11 and a pressure control valve 111 and a temperature control valve 112 sequentially arranged on the steam header 11 from upstream to downstream. Hot steam is used as the heat source for the gas replacement cylinder constant temperature system of this embodiment of the invention. For example, the heat source can come from the auxiliary steam system of a thermal power plant or the steam extraction system of the low-pressure area of ​​a steam turbine. The hot steam enters the steam header 11 from the input end of the steam header 11.

[0034] The heat exchange unit includes a cylinder heating box 21 and a condenser 22. The cylinder heating box 21 contains multiple gas cylinders. The cylinder heating box 21 is provided with a first steam inlet and a first steam outlet. The outlet of the steam header 11 is connected to the first steam inlet. The condenser 22 has a second steam inlet and a second steam outlet. The first steam outlet is connected to the second steam inlet via a pipeline.

[0035] Understandably, gas cylinders are used to connect to gas replacement systems, such as those used in the gas replacement work of hydrogen-cooled generator sets in the thermal power generation industry. During the process of replacing the gas inside the hydrogen-cooled generator set using gas (carbon dioxide or nitrogen) from gas cylinders, the required heat is provided by the hot steam from the steam control unit.

[0036] Hot steam enters the cylinder heating box 21 through the steam header 11 and the first steam input end, thereby heating the cylinder body of the gas cylinder in the cylinder heating box 21 to keep the gas cylinder in a constant temperature state and prevent the cylinder body from frosting or freezing, which would affect the efficiency and speed of the gas conversion from liquid to gas.

[0037] Furthermore, the pressure probe of the pressure control valve 111 is installed on the inlet pipe of the gas replacement system to detect the pressure in the inlet pipe (i.e., the pressure of the remaining gas in the gas cylinder). When the gas pressure in the inlet pipe of the gas replacement system is higher than the minimum pressure required by the gas cylinder, the pressure control valve 111 automatically opens. When the gas pressure in the inlet pipe of the gas replacement system is lower than the minimum pressure required by the gas cylinder, the pressure control valve 111 automatically closes.

[0038] The temperature probe of the temperature control valve 112 is located inside the gas cylinder heating chamber 21 to detect the temperature of the steam inside the chamber (i.e., the ambient temperature inside the chamber). When the temperature inside the heating chamber 21 is lower than the maximum allowable temperature of the gas cylinder, the temperature control valve 112 automatically opens. When the temperature inside the heating chamber 21 reaches the maximum allowable temperature of the gas cylinder, the temperature control valve 112 automatically closes slightly or completely, thereby maintaining a basically constant temperature inside the heating chamber 21 and meeting the heat absorption requirements for the release of high-pressure liquid gas from the gas cylinder.

[0039] The automatic start / stop functions of the pressure control valve 111 and the temperature control valve 112 can be implemented by connecting to the factory DCS control system or by connecting to a programmable PLC controller separately.

[0040] After heat exchange, the steam in the cylinder heating box 21 flows out of the cylinder heating box 21 through the first steam output end, and then enters the condenser 22 through the pipeline and the second steam input end. The condenser 22 is connected to the factory cooling water system, and the steam containing residual heat continuously condenses into liquid water under the action of circulating cooling water.

[0041] The steam venting unit includes a steam venting header 31, multiple first steam venting pipes 32, and a butterfly valve 321, a blower 322, and a check valve 323 sequentially arranged on the first steam venting pipes 32 from upstream to downstream. The input end of the first steam venting pipe 32 is connected to the second steam output end, and the output end of the first steam venting pipe 32 is connected to the steam venting header 31.

[0042] Optionally, such as Figure 1 As shown, there are two first exhaust pipes 32, which are connected in parallel. Each first exhaust pipe 32 is equipped with a butterfly valve 321, a blower 322, and a check valve 323. One of the two first exhaust pipes 32 is in use and the other is on standby. The check valve 323 is used to ensure that the operation of the blower 322 does not affect the safe and stable operation of the gas replacement cylinder constant temperature system of this embodiment of the invention.

[0043] After releasing heat, the exhaust steam flows through the condenser 22 and is transported by the first exhaust pipe 32 to the exhaust header 31 under the suction of the fan 322, and then discharged into the atmosphere through the exhaust header 31.

[0044] Therefore, in the gas replacement cylinder constant temperature system of this invention, hot steam enters the heat exchange unit under the control of the steam control unit, and the exhaust steam after heat exchange is completed is discharged from the system through the condensate venting unit. Using hot steam as a heat source to heat the cylinder body at a constant temperature solves the problems of inefficiency and impact on civilized production caused by using cold water to spray the cylinder in related technologies. It also effectively avoids the risks of electric shock and safety hazards associated with heating the cylinder by laying electric heating blankets on the cylinder surface or placing the cylinder in an electric heating box (with several electric heating rods arranged inside the box to indirectly heat the cylinder body by raising the temperature of the air inside the box).

[0045] Furthermore, the gas replacement cylinder constant temperature system of this invention is not only applicable to the gas replacement work of hydrogen-cooled generator sets in the thermal power generation industry, but also to the gas replacement work of dangerous, toxic, and harmful gas systems and storage tanks in various steel, chemical, and logistics warehousing industries using gas in cylinders.

[0046] In some embodiments, such as Figure 1 As shown, the steam control unit also includes a pressure reducing valve 113 and a throttling device 114. The pressure reducing valve 113 is located on the steam header 11 and upstream of the pressure control valve 111, while the throttling device 114 is located inside the steam header 11 and downstream of the temperature control valve 112.

[0047] Understandably, the pressure reducing valve 113 controls the pressure reduction of the flowing steam, and the throttling device 114 is a throttling orifice plate. The hot steam is reduced in pressure by the pressure reducing valve 113 and flows into the cylinder heating box 21 under the control of the temperature control valve 112 and the throttling orifice. Furthermore, the need for the pressure reducing valve 113 and the throttling device 114 can be determined based on the parameters of the connected hot steam system, or one of them can be chosen arbitrarily or used as a selection criterion.

[0048] In some embodiments, such as Figure 1As shown, the steam control unit also includes a shut-off valve 115 and a gate valve 116. Both shut-off valve 115 and gate valve 116 are located on the steam header 11. The shut-off valve 115 is located upstream of the pressure reducing valve 113, and the gate valve 116 is located downstream of the temperature control valve 112 and upstream of the throttling device 114.

[0049] It is understood that the shut-off valve 115 and the gate valve 116 are used to isolate the hot steam flowing through the steam control unit, and to isolate the gas replacement cylinder constant temperature system of this embodiment of the invention during maintenance or long-term shutdown.

[0050] Therefore, the functional flow of the steam control unit is as follows: hot steam flows from shut-off valve 115 → pressure reducing valve 113 → pressure control valve 111 → temperature control valve 112 → gate valve 116 → throttle orifice.

[0051] In some embodiments, such as Figure 1 As shown, the steam control unit also includes a steam sub-pipe 12 and a first normally closed gate valve 121 disposed on the steam sub-pipe 12. The input end of the steam sub-pipe 12 is connected to the steam main pipe 11 located between the pressure reducing valve 113 and the pressure control valve 111, and the output end of the steam sub-pipe 12 is connected to the steam main pipe 11 located between the gate valve 116 and the throttling device 114.

[0052] It is understandable that a bypass is provided between the pressure reducing valve 113 and the throttling device 114 to manually adjust the steam intake in case the pressure control valve 111 or the temperature control valve 112 fails or needs to be repaired.

[0053] In some embodiments, such as Figure 1 As shown, the condensate venting unit also includes a straight vent pipe 33 and a normally closed shut-off valve 331 installed on the straight vent pipe 33, a first U-shaped water seal 35 and a second funnel 36 connected thereto, as well as a second U-shaped water seal 37 and a third funnel 38 connected thereto.

[0054] The inlet of the straight pipe 33 is connected to the steam header 11 located between the inlet of the pressure reducing valve 113 and the inlet of the steam sub-pipe 12. The outlet of the straight pipe 33 is provided with a first funnel 34. The cylinder heating box 21 is also provided with a first condensate drain, and the condenser 22 is also provided with a second condensate drain. The first and second condensate drains are connected to the first U-shaped water seal 35 via pipelines. The exhaust header 31 is connected to the second U-shaped water seal 37.

[0055] It is understood that a U-shaped water seal or a straight discharge pipe 33 controlled by a shut-off valve is installed on the pipeline between the pressure reducing valve 113 and the temperature control valve 112, at the bottom of the gas cylinder heating box 21 (first condensate drain end), at the bottom of the condenser 22 (second condensate drain end), and at the bottom of the exhaust header 31, so as to better discharge the condensate generated at each functional position of the gas replacement gas cylinder constant heat system of this embodiment of the invention to the outside of the system.

[0056] For example, the first U-shaped water seal 35 can seal the slight negative pressure inside the cylinder heating box 21 and the condenser 22. The condensate will only be discharged from the box when the condensate level is higher than the highest point of the first U-shaped water seal 35. The outlet of the first U-shaped water seal 35 is connected (or connected through a funnel) to the low-level drain header of the plant.

[0057] Specifically, the first funnel 34, the second funnel 36 and the third funnel 38 are all connected to the low-level water discharge header of the plant, and the funnels can be used to observe the water discharge situation.

[0058] In some embodiments, such as Figure 1 As shown, the steam venting unit also includes a second steam venting pipe 39 and a second normally closed gate valve 391 installed on the second steam venting pipe 39. The input end of the second steam venting pipe 39 is connected to the second steam output end, and the output end of the second steam venting pipe 39 is connected to the steam venting header 31.

[0059] It is understood that a bypass consisting of a normally closed gate valve 116 and pipeline is provided for the condensate venting unit to meet the operational requirements of the gas replacement cylinder constant heat system of this embodiment of the invention when the blower 322 fails to vent.

[0060] The temperature control method of the present invention is described below with reference to the accompanying drawings.

[0061] like Figure 2 As shown, the temperature control method of this invention is used in the gas replacement cylinder constant temperature system of any of the above embodiments. The method includes:

[0062] When the temperature T measured by the temperature probe of the temperature control valve 112 is higher than the temperature set value T0, the opening degree of the temperature control valve 112 is reduced.

[0063] When the temperature T measured by the temperature probe of the temperature control valve 112 is lower than the temperature set value T0, the opening of the temperature control valve 112 is increased to maintain the temperature inside the cylinder heating box 21 within the temperature set value T0.

[0064] When the temperature T measured by the temperature probe of the temperature control valve 112 reaches T1, the temperature control valve 112 is closed.

[0065] When the pressure probe of pressure control valve 111 measures that the pressure in the gas exchange system’s inlet pipe reaches or falls below the minimum allowable pressure P of the gas cylinder, or when the temperature probe of temperature control valve 112 measures that the temperature reaches T1 and does not drop after 10 seconds, pressure control valve 111 is closed.

[0066] When the temperature control valve 112 and the pressure control valve 111 are closed at the same time, the fan 322 will be shut down after a delay of 20 seconds.

[0067] The temperature setpoint T0 has a range of 35 to 40°C, T1 has a set temperature of 40°C, and the minimum allowable pressure P of the gas cylinder is 0.1 MPa.

[0068] In addition, the automatic start-stop functions of pressure control valve 111, temperature control valve 112 and fan 322 are achieved by connecting to the factory DCS control system or by connecting to a programmable PLC controller separately.

[0069] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0070] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0071] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0072] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0073] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0074] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A gas-displacement cylinder constant-temperature system, characterized in that, include: A steam control unit, comprising a steam header and a pressure control valve and a temperature control valve sequentially arranged on the steam header from upstream to downstream; A heat exchange unit includes a gas cylinder heating box and a condenser. The gas cylinder heating box contains multiple gas cylinders. The gas cylinder heating box is provided with a first steam input end and a first steam output end. The output end of the steam header is connected to the first steam input end. The condenser has a second steam input end and a second steam output end. The first steam output end is connected to the second steam input end via a pipeline. The pressure probe of the pressure control valve is located on the gas inlet pipeline of the gas replacement system. The temperature probe of the temperature control valve is located inside the gas cylinder heating box. A steam venting unit includes a steam venting header, multiple first steam venting pipes, and a butterfly valve, a blower, and a check valve sequentially arranged on the first steam venting pipes from upstream to downstream. The input end of the first steam venting pipe is connected to the second steam output end, and the output end of the first steam venting pipe is connected to the steam venting header. The cylinder heating box is also provided with a first condensate drain, the condenser is also provided with a second condensate drain, and the condensate venting unit is also provided with a first U-shaped water seal and a second funnel connected together. The first condensate drain and the second condensate drain are connected to the first U-shaped water seal via pipelines.

2. The gas replacement cylinder constant temperature system according to claim 1, characterized in that, The steam control unit also includes a pressure reducing valve and a throttling device. The pressure reducing valve is located on the steam header and upstream of the pressure control valve, and the throttling device is located inside the steam header and downstream of the temperature control valve.

3. The gas replacement cylinder constant temperature system according to claim 2, characterized in that, The steam control unit also includes a shut-off valve and a gate valve, both of which are located on the steam header. The shut-off valve is located upstream of the pressure reducing valve, and the gate valve is located downstream of the temperature control valve and upstream of the throttling device.

4. The gas replacement cylinder constant temperature system according to claim 3, characterized in that, The steam control unit further includes a steam sub-pipe and a first normally closed gate valve disposed on the steam sub-pipe. The input end of the steam sub-pipe is connected to the steam main pipe located between the pressure reducing valve and the pressure control valve, and the output end of the steam sub-pipe is connected to the steam main pipe located between the gate valve and the throttling device.

5. The gas replacement cylinder constant temperature system according to claim 4, characterized in that, The condensate venting unit also includes a direct venting pipe and a normally closed shut-off valve installed on the direct venting pipe. The input end of the direct venting pipe is connected to the steam header located between the pressure reducing valve and the input end of the steam sub-pipe. The output end of the direct venting pipe is provided with a first funnel.

6. The gas replacement cylinder constant temperature system according to claim 1, characterized in that, The condensate venting unit also includes a second U-shaped water seal and a third funnel connected together, and the venting header is connected to the second U-shaped water seal.

7. The gas replacement cylinder constant temperature system according to claim 1, characterized in that, The condensate venting unit further includes a second venting pipe and a second normally closed gate valve installed on the second venting pipe. The input end of the second venting pipe is connected to the second steam output end, and the output end of the second venting pipe is connected to the venting header.

8. A temperature control method, characterized in that, The method is used in the gas displacement cylinder constant temperature system as described in any one of claims 1-7, and the method includes: When the temperature T measured by the temperature probe of the temperature control valve is higher than the temperature set value T0, the opening degree of the temperature control valve is reduced. When the temperature T measured by the temperature probe of the temperature control valve is lower than the temperature set value T0, the opening of the temperature control valve is increased to maintain the temperature inside the cylinder heating box within the temperature set value T0. When the temperature T measured by the temperature probe of the temperature control valve reaches T1, the temperature control valve is closed. When the pressure probe of the pressure control valve measures that the pressure in the gas replacement system’s inlet pipe reaches or falls below the minimum allowable pressure P of the gas cylinder, or when the temperature probe of the temperature control valve measures that the temperature reaches T1 and the temperature has not dropped after 10 seconds, the pressure control valve is closed. The temperature setting value T0 has a parameter range of 35~40℃, T1 has a temperature of 40℃, and the minimum allowable pressure P of the gas cylinder is 0.1MPa.

9. The temperature control method according to claim 8, characterized in that, When the temperature control valve and the pressure control valve are closed simultaneously, the fan will stop after a 20-second delay.

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