A refrigeration cycle piping system, control method and application

Abstract

The present invention belongs to the technical field of artificial freezing of urban underground space, and discloses a novel refrigeration circulation pipeline system, a control method and an application. In the refrigeration circulation pipeline, the height difference of different pipe diameters and the pressure difference caused by the inner and outer pipe structures are used to make the refrigerant medium circulate rapidly in the pipe. The refrigerant liquid inlet pipe channel is sleeved on the inner side of the upper end of the refrigerant liquid outlet circulation channel; the refrigerant liquid inlet pipe channel is provided with a liquid inlet pipe, and the upper end of the liquid inlet pipe is connected to a liquid inlet; the upper outer part of the refrigerant liquid outlet circulation channel is connected to a liquid outlet, and the lower end of the refrigerant liquid outlet circulation channel is hot-melt connected with a plug. Compared with traditional seamless steel pipe-type refrigeration circulation pipelines, the present invention has fast and sufficient circulation, good cold brittleness, less pollution to the underground environment, and low cost; high reuse rate, flexible arrangement form and simple structure of the freezing pipe; easy on-site installation and operation in engineering, saving engineering costs.

Description

Technical Field

[0001] The invention belongs to the technical field of artificial freezing of urban underground space, and in particular relates to a novel refrigeration circulation pipeline system, a control method and an application thereof, which are suitable for temporary support engineering in deep foundation pit engineering. Background Art

[0002] At present, the artificial freezing technology for deep foundation pits in the soil layer is to use the characteristics of high soft soil content, insert freezing pipes into the soil around the site to be excavated, and freeze the soil to form a soil with a certain structural strength, which is used as the retaining structure for foundation pit construction. At present, many foundation pits constructed by conventional support methods in China have experienced collapse and instability accidents to varying degrees. The frozen wall of artificial freezing construction has both structural strength and impermeability. The reasonable application of this technology has advantages that other conventional methods do not have. At present, artificial freezing technology has developed into a mature construction method and has been widely used in temporary reinforcement of underground engineering foundations, groundwater pollution control, waste landfill and other fields. The frozen soil temperature is an important indicator to measure the freezing effect and a very important safety index. Therefore, the full circulation of the freezing pipe in the artificial freezing technology is crucial to the frozen soil temperature. In the early artificial freezing technology, the form of the freezing circulation pipeline usually uses rigid materials such as seamless steel pipes and adopts welding technology. On the one hand, the toughness of steel pipes decreases at negative temperatures and they tend to become brittle at low temperatures. In addition, steel is easily corroded and rusted, which not only pollutes the soil, but also contaminates the refrigeration medium and weakens its freezing effect. On the other hand, once the original seamless steel pipe refrigeration cycle pipeline arrangement is welded, the form cannot be changed at will, and the construction procedure is complicated and inconvenient for on-site splicing and installation.

[0003] Through the above analysis, the problems and defects of the prior art are as follows:

[0004] (1) The existing refrigeration cycle pipelines have reduced toughness at negative temperatures and tend to become brittle at low temperatures. In addition, the steel is easily corroded and rusted, which not only pollutes the soil, but also contaminates the refrigeration medium, weakening its refrigeration effect.

[0005] (2) Once the original seamless steel pipe refrigeration cycle pipeline is welded, the arrangement cannot be changed at will, and the construction procedure is complicated and inconvenient for on-site splicing and installation.

[0006] (3) The liquid inlet and outlet pipes of the traditional freezing pipe are two different inner pipes arranged in parallel inside the structure. The refrigerant needs a very high pressure to flow out of the liquid outlet, which places high power requirements on the low-temperature circulation machine, and the heat exchange effect with the soil is not good during the outflow process.

[0007] (4) Traditional refrigeration pipes are of a single type and are connected to form a refrigeration cycle system by welding stainless steel pipes on the top. During the connection process, holes need to be drilled on the upper stainless steel pipes, which is a complicated operation.

[0008] The difficulty of solving the above problems and defects is:

[0009] (1) In foundation pit tunnel projects and other underground projects, preventing and controlling underground pollution caused by construction has become a key issue in the construction process. However, the low-temperature brittleness of many materials does not meet the required requirements for artificial freezing technology. In addition, the construction procedure is complicated, the installation of freezing pipes is complicated, and seamless steel pipes and other materials need to be sheared and welded, which is difficult and complicated to operate.

[0010] (2) The traditional form of freezing pipe requires a large power of the circulation pump of the refrigeration cycle machine. During on-site construction, the voltage may not reach the specified voltage of the refrigeration cycle machine.

[0011] (3) The traditional freezing pipe does not exchange cold air sufficiently, requiring a large number of freezing pipes and a long time to form.

[0012] The significance of solving the above problems and defects is:

[0013] The use of PE pipes can effectively solve the cold brittleness problem of rigid materials at negative temperatures. PE pipes are environmentally friendly and energy-saving, and the simple construction operation can greatly reduce the operating procedures and time, saving costs.

[0014] In the invention, the height difference between the different pipe diameters of the inner and outer structures and the pressure difference caused by the inner and outer pipe structures are used in the refrigeration circulation pipeline to make the refrigerant medium circulate quickly in the pipe, and the power requirement for the circulation pump is reduced through its own pressure difference.

[0015] The above measures enable the present invention to fully and quickly exchange temperature between the freezing pipe and the soil, so that the soil can reach the required temperature in a shorter time and accelerate the formation of the frozen soil retaining wall. Summary of the invention

[0016] In view of the problems existing in the prior art, the present invention provides a novel refrigeration cycle piping system, a control method and an application thereof.

[0017] The present invention is achieved in this way, a new type of refrigeration cycle regulation method, the new type of refrigeration cycle regulation method includes: the circulating liquid outlet channel is similar to a U-tube pressure gauge, because the internal pressure of the liquid increases with the increase of depth; and decreases with the increase of contact area. This device uses the height difference of different pipe diameters and the pressure difference caused by the inner and outer pipe structures to make the refrigerant medium circulate fully and quickly in the pipe, thereby increasing the rate of temperature exchange between the freezing pipe and the soil.

[0018] ∵P=F / S

[0019] F=G=mg

[0020] m=ρv

[0021] ∴P=ρgh

[0022] h1=1.2m;h2=1.1m

[0023] P1=ρgh1=1.1155×10×1.2=13.386Pa

[0024] P2=ρgh2=1.1155×10×1.1=11.155Pa

[0025] r1=1.6cm;r2=1.0cm

[0026] S1=πr 2 =3.14×1.6 2 =8.0384cm 2

[0027] S2=πr 2 =3.14×1 2 =3.14cm 2

[0028] ∵P1=F / S1

[0029] ∴F=P1×S1=8.0384×10 -4 ×13.386=1.076×10 -2 N

[0030] P3=F / S2=1.076×10 -2 ÷3.14×10 -4 =34.27Pa

[0031] Note: The refrigeration medium is ethylene glycol solution, and its density is ρ = 1.1155kg / m 3 ; (g is 10.0m / s 2 )

[0032] S1 is the cross-sectional area of ​​the outer tube; S2 is the cross-sectional area of ​​the inner tube;

[0033] r1 is the outer tube radius; r2 is the inner tube radius

[0034] h1 is the total length of the freezing tube; h2 is the length of the freezing tube liquid inlet pipe;

[0035] P1 is the pressure at the bottom cross section of the cryotube;

[0036] P2 is the pressure at the cross section at the bottom of the inner tube of the outer tube of the cryotube;

[0037] P3 is the pressure at the bottom cross section of the inner tube of the cryotube;

[0038] Due to the pressure difference between P1 and P3, after reaching the bottom of the outer tube, the refrigerant moves upward along the outer wall of the inner tube under the pressure difference until it flows out from the liquid outlet.

[0039] Furthermore, the refrigeration circulation pipeline is made of PE material to form a PE circulation pipe.

[0040] Furthermore, PE circulation pipes of different diameters are tightly connected through reducers using welding and hot-melt technology.

[0041] Furthermore, the reducer includes an end angle type and a middle connection type, which can be changed at will in connection lines with different pipe diameters.

[0042] Furthermore, the arrangement of the refrigeration cycle pipelines is designed according to actual engineering requirements.

[0043] Another object of the present invention is to provide a novel refrigeration cycle piping system comprising:

[0044] A refrigerant liquid inlet pipe channel and a refrigerant liquid outlet circulation channel;

[0045] The refrigerant liquid inlet pipe channel is sleeved on the inner side of the upper end of the refrigerant liquid outlet circulation channel;

[0046] The refrigerant liquid inlet pipe channel is provided with a liquid inlet pipe, and the upper end of the liquid inlet pipe is connected with a liquid inlet port;

[0047] The upper outer portion of the refrigerant liquid outlet circulation channel is connected with a liquid outlet, and the lower end of the refrigerant liquid outlet circulation channel is hot-melt connected with a plug.

[0048] Furthermore, the liquid inlet is provided with a right-angle turn or a three-way connecting joint, the right-angle turn is connected to the liquid inlet pipe through a reducer, and the three-way connecting joint is hot-melt connected to the upper end of the liquid inlet pipe.

[0049] Furthermore, a gap is provided between the lower end of the liquid inlet pipe and the plug.

[0050] Furthermore, the refrigerant liquid inlet pipe channel and the refrigerant liquid outlet circulation channel both use PE water pipes.

[0051] Another object of the present invention is to provide an application of the novel refrigeration cycle control method in the fields of temporary reinforcement of underground engineering foundations, groundwater pollution control, and waste landfill.

[0052] Combining all the above technical solutions, the advantages and positive effects of the present invention are as follows:

[0053] The circulating liquid outlet channel between the inner and outer tubes of the present invention is similar to a closed U-tube manometer. Due to the characteristics of the internal pressure of the liquid: the liquid has pressure from the inside to all directions, the pressure increases with the increase of depth; and decreases with the increase of the contact area. The device uses the pressure difference caused by the high potential difference between the inner and outer tubes and the different cross-sectional areas of the inner and outer tubes to make the refrigerant medium circulate fully and quickly in the tube, thereby increasing the rate of temperature exchange between the freezing tube and the soil, which is of great significance to the freezing wall handover time and the rapid formation of the temperature field.

[0054] Structural accessories of the present invention Figure 1 The middle part 3 is a reducer, and the middle connection uses a reducer, with the large diameter facing upward and the small diameter facing downward, forming a funnel-like operation to ensure that the refrigerant medium completely enters the inner tube, thereby ensuring the circulation effect.

[0055] The 6-tee interface in the structural accessory diagram of the present invention is used as a circulating liquid outlet to avoid drilling and other processes in the connection, thereby reducing the difficulty of construction.

[0056] In the structural accessory diagram of the present invention, 1-end corner joint and 2-tee connecting joint, the liquid inlet is divided into end corner and middle tee connection types, which are respectively suitable for different positions and are easier to connect and install in actual projects.

[0057] The above structure enables the present invention to fully and quickly exchange temperature between the freezing pipe and the soil, so that the soil can reach the required temperature in a shorter time and accelerate the formation of the frozen soil retaining wall.

[0058] The present invention overcomes the defect of easy corrosion of the traditional refrigeration cycle piping system. When the traditional seamless steel pipe and other refrigeration cycle systems are used as refrigeration pipes, anti-corrosion measures must be taken to prevent corrosion and underground pollution. When ethylene glycol (CH2OH)2 is used as the refrigerant medium, acidic substances are easily generated during the refrigeration cycle, which has a corrosive effect on metals. The present invention adopts PE water pipes, which are non-toxic and have good anti-corrosion properties, and are a new type of environmentally friendly material.

[0059] In the past, the traditional refrigeration cycle piping system was made of steel and used welding technology. The steel had poor cold brittleness. Once welded, the structure could not be changed, and the manufacturing and installation procedures were complicated. The present invention uses welding hot melt technology, and the pipes are tightly connected. The structural form is divided into end corner type and middle connection type. The connection form can be changed at will, and the reuse rate is high. The PE pipe can maintain good toughness at -60° and has good cold brittleness.

[0060] The present invention has a simple structure and utilizes different pipe diameters and the high potential difference between the inner and outer pipes to allow the refrigerant to circulate fully and quickly inside and outside the pipe independently; the reducer can ensure that the liquid directly enters the inner pipe, thereby allowing the refrigerant to circulate fully between the inner and outer pipe walls, thereby increasing the rate of temperature exchange between the freezing pipe and the soil, which is of great significance to the freezing wall handover time and the rapid formation of the temperature field.

[0061] The invention has economical cost and high recycling rate and is an economical and environment-friendly material. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0063] Figure 1 It is a cross-sectional view of the end corner internal structure provided by an embodiment of the present invention.

[0064] Figure 2 It is a cross-sectional view of the middle connection type internal structure provided by an embodiment of the present invention.

[0065] Figure 3 It is a cross-sectional view of the middle connection type and end corner type liquid inlet structure provided by the embodiment of the present invention.

[0066] Figure 4 It is a cross-sectional view of the external circulation liquid outlet structure provided by an embodiment of the present invention.

[0067] Figure 5 This is a rendering of a single-row connection provided by an embodiment of the present invention.

[0068] In the figure: 1. right-angle turn; 2. three-way connecting joint; 3. reducing joint; 4. plug; 5. liquid inlet; 6. circulating liquid outlet; 7. liquid inlet pipe; 8. circulating liquid outlet pipe. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0070] In view of the problems existing in the prior art, the present invention provides a novel refrigeration cycle piping system, which is described in detail below in conjunction with the accompanying drawings.

[0071] The present invention provides a novel refrigeration cycle control method, which comprises: utilizing the height difference of different pipe diameters and the pressure difference caused by the inner and outer pipe structures in the refrigeration cycle pipeline to make the refrigeration medium circulate quickly in the pipe.

[0072] Preferably, the refrigeration circulation pipeline is made of PE material to form a PE circulation pipe.

[0073] Preferably, PE circulation pipes of different diameters are tightly connected through reducers using welding and hot-melt technology.

[0074] Preferably, the reducer includes an end angle type and a middle connection type, which can be freely changed in connection lines with different pipe diameters.

[0075] Preferably, the arrangement of the refrigeration cycle pipelines is designed according to actual engineering requirements.

[0076] like Figures 1 to 4 As shown, the refrigeration cycle piping system provided by the embodiment of the present invention is mainly composed of two parts, the inner and outer parts; the inner part is the refrigerant liquid inlet pipe channel, and the outer part is the refrigerant liquid outlet circulation channel.

[0077] The liquid inlet is divided into two types: end corner liquid inlet and middle connecting liquid inlet.

[0078] The refrigeration circulation piping system is formed by connecting right-angle turners, reducers, tees, plugs and PE pipes with diameters of Φ20 and Φ32 using hot-melt welding technology, and the connected single pipes are connected in parallel to form the refrigeration circulation piping system.

[0079] End freezing pipe structure: This refrigeration cycle piping system is designed based on a wall thickness of 1m and can be enlarged in proportion if necessary. The upper part is connected to a Φ32 right-angle turn head, and the vertical and horizontal joints are connected to a PE water pipe with a length of 10cm and a diameter of Φ32. A Φ32-20 reducer is connected to the lower end, so that the refrigerant inlet is funnel-shaped to ensure that the refrigerant enters the inner pipe structure with a diameter of Φ20. The lower end of the Φ20 reducer is connected to a PE water pipe with a length of 10cm and a diameter of Φ20, and then connected to a Φ20-32 reducer. The above is the upper structure of the refrigeration cycle piping system, which only has the outer wall of the pipe and no inner pipe design. The pipe structure described later will have an internal structure design.

[0080] Connect a Φ20 diameter casing to the area where the inner diameter of the Φ32 end of the reducer is reduced, and connect a 80cm long PE water pipe to the lower end of the casing as the internal liquid inlet pipe. Connect a 10cm long Φ32 diameter PE water pipe to the inner side of the Φ32 end of the outer diameter reducer of the casing, and connect the lower end to the tee joint. The Φ32 ends at both ends are placed vertically, and the Φ20 interface faces the direction of the turn head, so that it is convenient to connect to the inlet and outlet circulation frame system. Connect a 80cm long Φ32 diameter PE water pipe to the Φ32 interface at the lower end of the tee, and connect the lower end to the Φ32 plug. The inner Φ20 pipe is 80cm long, and the outer pipe length is 10cm under the reducer plus 80cm, so the outer pipe length is 90cm. The outer pipe is 10cm longer than the inner pipe. The high potential difference between the inner and outer pipes is used to allow the refrigerant medium to circulate quickly on the outer pipe wall, flowing from the inner pipe into the outer pipe wall and out through the Φ20 three-way outlet, thus forming an internal and external refrigeration circulation pipeline system.

[0081] The reducer can ensure that the liquid enters the inner tube directly, thereby ensuring that the refrigerant circulates fully on the outer tube wall.

[0082] New environmentally friendly and pollution-free PE pipes are used to replace seamless steel pipes and other forms of refrigeration cycle pipes. Tests have shown that PE pipes will not freeze and crack at a low temperature of -60 degrees.

[0083] By adopting hot-melt welding method, various forms of refrigeration circulation piping systems required can be quickly spliced ​​on site.

[0084] PE pipes of different diameters are used, and the liquid inlet and outlet pipes utilize different high potential differences to allow the freezing medium to circulate quickly by its own gravity.

[0085] An annular structure is formed between the inner and outer pipes. There is a certain pipe pressure at the contact point between the two pipes, which greatly reduces the pipe diameter of the refrigeration medium circulation, reduces the loss of cold, and can increase the circulation rate, so that the soil can reach the required temperature in a shorter time and accelerate the formation of the frozen soil retaining wall.

[0086] The intermediate structure utilizes a reducer to connect the liquid inlet to ensure that the refrigerant medium can accurately enter the liquid inlet pipe during the liquid inlet process, thereby ensuring an efficient circulation effect.

[0087] The liquid inlet and the liquid outlet can be connected to other devices by hot-melt welding. If a refrigeration cycle machine needs to be connected, the corresponding PE hose can be used to connect and fix it with steel wire.

[0088] like Figure 5 As shown, the structure of this embodiment is a single-row structure; Figure 1 The corner opening of one end is facing inwards, and four connecting type freezing pipes are placed in the middle and the other end, and the liquid outlet is facing outwards. The upper liquid inlet is connected to the Φ32 pipe from the right angle joint, and the lower liquid outlet is a Φ20 pipe. The joints are installed with equal diameter 20 tee joints and then connected with Φ20 freezing pipes in turn. The corners are also connected with right angle joints. When connecting the liquid inlet and the side of the liquid inlet close to the machine, connect the equal diameter Φ32 and Φ20 tee joints, and connect the Φ32 and Φ20 pipes to the exposed end of the joint to extend it so as to facilitate access to the refrigeration cycle machine.

[0089] The working principle of the present invention is:

[0090] The present invention uses a PE pipe material different from the previous one as the material for the freezing pipe, and the circulating liquid outlet channel between the inner and outer pipes is similar to a closed U-tube manometer. Due to the characteristics of the internal pressure of the liquid: the liquid has pressure in all directions from the inside, the pressure increases with the increase of depth; and decreases with the increase of contact area. This device uses the pressure difference caused by the high potential difference between the inner and outer pipes and the different cross-sectional areas of the inner and outer pipes to make the refrigerant medium circulate fully and quickly in the pipe, thereby increasing the rate of temperature exchange between the freezing pipe and the soil, which is of great significance to the freezing wall handover time and the rapid formation of the temperature field. Structural accessories Figure 1 The middle part 3 is a reducer, and the middle connection uses a reducer, with the large diameter facing upward and the small diameter facing downward, forming a funnel-like operation to ensure that the refrigerant medium completely enters the inner tube, thereby ensuring the circulation effect. The 6-tee interface in the structural accessory diagram serves as a circulation outlet to avoid drilling and other processes during the connection, thereby reducing the difficulty of construction. The 1-end corner joint and the 2-tee connection joint in the structural accessory diagram, the liquid inlet is divided into an end corner and a middle tee connection type, which are respectively suitable for different positions, and are easier to connect and install in actual engineering. The present invention is used to solve the problems that traditional freezing pipes are prone to corrosion and pollution of the underground, the internal circulation rate of the freezing pipes is low and the circulation is not sufficient, the fixed structure is not convenient for on-site installation and construction operations, and the reuse rate is low.

[0091] The calculation process of generating pressure difference:

[0092] ∵P=F / S

[0093] F=G=mg

[0094] m=ρv

[0095] ∴P=ρgh

[0096] h1=1.2m;h2=1.1m

[0097] P1=ρgh1=1.1155×10×1.2=13.386Pa

[0098] P2=ρgh2=1.1155×10×1.1=11.155Pa

[0099] r1=1.6cm;r2=1.0cm

[0100] S1=πr 2 =3.14×1.6 2 =8.0384cm 2

[0101] S2=πr 2 =3.14×1 2 =3.14cm 2

[0102] ∵P1=F / S1

[0103] ∴F=P1×S1=8.0384×10 -4 ×13.386=1.076×10 -2 N

[0104] P3=F / S2=1.076×10 -2 ÷3.14×10 -4 =34.27Pa

[0105] Note: The refrigeration medium is ethylene glycol solution, and its density is ρ = 1.1155kg / m 3 ; (g is 10.0m / s 2 )

[0106] S1 is the cross-sectional area of ​​the outer tube; S2 is the cross-sectional area of ​​the inner tube;

[0107] r1 is the outer tube radius; r2 is the inner tube radius

[0108] h1 is the total length of the freezing tube; h2 is the length of the freezing tube liquid inlet pipe;

[0109] P1 is the pressure at the bottom cross section of the cryotube;

[0110] P2 is the pressure at the cross section at the bottom of the inner tube of the outer tube of the cryotube;

[0111] P3 is the pressure at the bottom cross section of the inner tube of the cryotube;

[0112] Due to the pressure difference between P1 and P3, after reaching the bottom of the outer tube, the refrigerant moves upward along the outer wall of the inner tube under the pressure difference until it flows out from the liquid outlet.

[0113] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0114] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A refrigeration cycle piping system, characterized in that: The refrigeration cycle piping system is provided with: A refrigerant liquid inlet pipe channel and a refrigerant liquid outlet circulation channel; The refrigerant liquid inlet pipe channel is sleeved on the inner side of the upper end of the refrigerant liquid outlet circulation channel; The refrigerant liquid inlet pipe channel is provided with a liquid inlet pipe, and the upper end of the liquid inlet pipe is connected with a liquid inlet port; The upper portion of the outer side of the refrigerant liquid outlet circulation channel is connected with a liquid outlet, and the lower end of the refrigerant liquid outlet circulation channel is hot-melt connected with a plug; The liquid inlet is provided with a reducer, which includes an end angle type and a middle connection type, and the small diameter end of the reducer is connected to the liquid inlet pipe; A gap is arranged between the lower end of the liquid inlet pipe and the plug.

2. The refrigeration cycle piping system according to claim 1, characterized in that: The refrigerant liquid inlet pipe channel and the refrigerant liquid outlet circulation channel both adopt PE water pipes.

3. A refrigeration cycle control method for a refrigeration cycle piping system according to any one of claims 1 to 2, characterized in that: The refrigeration cycle control method comprises: utilizing the height difference of different pipe diameters and the pressure difference caused by the inner and outer pipe structures in the refrigeration cycle pipeline to make the refrigeration medium circulate quickly in the pipe; The refrigeration circulation pipeline is made of PE material to form a PE circulation pipe; PE circulation pipes of different diameters are tightly connected through reducers using welding and hot-melt technology; The reducer includes an end angle type and a middle connection type, which can be changed at will in connection lines with different pipe diameters; The arrangement of the refrigeration cycle pipelines is designed according to actual project requirements.

4. An application of the refrigeration cycle control method according to claim 3 in the fields of temporary reinforcement of underground engineering foundations, groundwater pollution control, and waste landfill.

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