Ground source heat pump outdoor heat exchange system buried pipe construction technology

Abstract

The invention relates to the technical field of ground source heat pump outdoor heat exchange systems, and discloses a ground source heat pump outdoor heat exchange system buried pipe construction technology which comprises the following steps that S1, a heat exchange well is constructed, specifically, the position of the heat exchange well is determined through survey lofting, and a small top drive drilling machine is adopted for guiding holes before drilling; the problems of hole collapse and hole channeling in the drilling process of the heat exchange well of the outdoor heat exchange system of the ground source heat pump are effectively solved, and the hole forming quality of the heat exchange well is improved; by optimizing the process and additionally arranging the geotechnical cloth, the problem of fine sand loss is solved, the compactness of a sand cushion and the mounting quality of a horizontal pipe are guaranteed, good social benefits are achieved, the part, protruding out of the top of the bucket body, of a soil body is collected into the bucket body through the anti-leakage bucket, and the soil body is prevented from falling off during follow-up overall movement of the bucket. And the situation that the soil body protruding out of the bucket body is blown off by strong wind and falls back into a groove is avoided, so that the falling soil body does not need to be dug out subsequently, and the working efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of the outdoor heat exchange system of a ground source heat pump, and particularly relates to a construction technology for buried pipes of an outdoor heat exchange system of a ground source heat pump. Background Art

[0002] In recent years, with the continuous development of the national green economy, the demand for clean energy has also been continuously increasing. In the field of new energy development, shallow geothermal energy resources are a kind of clean energy that can be continuously developed and utilized, which can replace some conventional energy sources. The ground source heat pump technology has many advantages such as remarkable environmental protection benefits, high energy efficiency, stable and reliable operation, high quality of refrigeration and heating, multi-functional use, wide application range, automatic operation, long service life, no damage to the building aesthetics, and no noise pollution, and has great development potential.

[0003] The construction quality of the buried pipes of the outdoor heat exchange system of a ground source heat pump has a great influence on the heat exchange efficiency of the ground source heat pump system and the later use effect. In the existing construction technology for buried pipes of the heat exchange system, due to the differences in geological conditions in different regions, the problems of hole collapse and hole channeling are prominent during the drilling process, and the verticality of the heat exchange well after hole formation is poor; during the installation of the horizontal pipe, due to the influence of rock fissures and pebble layer gaps at the bottom sand cushion layer, the loss of fine sand is relatively large, the compactness of the cushion layer is relatively low, and the horizontal pipe is prone to settlement and deformation after installation.

[0004] Therefore, it is very necessary to invent a construction technology for buried pipes of an outdoor heat exchange system of a ground source heat pump to solve the above problems. Summary of the Invention

[0005] In view of the above problems, the present invention provides a construction technology for buried pipes of an outdoor heat exchange system of a ground source heat pump to solve the problems raised in the above background art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A construction technology for buried pipes of an outdoor heat exchange system of a ground source heat pump, comprising the following steps:

[0008] S1. Construction of the heat exchange well:

[0009] Determine the position of the heat exchange well through measurement and lofting. Before drilling, use a small top drive drill to pilot hole, and set a steel casing in the soft stratum to prevent hole collapse. After the main drill is in place, the drill bit passes through the steel casing and continues to drill. The drill bit is provided with slurry discharge holes, and slurry is continuously transported from the slurry pool through a slurry pump, and the rock debris in the hole is carried out by the slurry;

[0010] After the drilling is completed and it is confirmed that the designed depth is reached, use a counterweight rod to assist the vertical double U-shaped PE pipe and the grouting pipe to go down the well. The PE pipe is lowered under pressure. After the PE pipe sinks to the designed depth, recover the counterweight rod, and then immediately carry out grouting construction. Wait until the slurry overflows the wellhead, and then pull out the grouting pipe;

[0011] After the grouting is completed, confirm that the grouting is dense and there is no cavity, then pull out the steel sleeve. After grouting and filling, maintain pressure for 24 hours. If the pressure gauge does not drop significantly, the installation of the PE pipe meets the system requirements, and the pressure gauge can be removed.

[0012] S2. Pilot hole construction:

[0013] For strata such as pebble layers that are not convenient for drilling, pilot hole construction is carried out before drilling. According to the determined wellhead position, use a top drive drill to drill. The pilot hole bit uses an opening bit for the first section of construction. Drill to the specified depth a, set up and bury the steel sleeve. For subsequent pilot holes, use an opening bit. Bury a section of steel sleeve every time the specified depth b is drilled. Use the hammering method to sink the steel sleeve. The final drilling depth is based on passing through special strata such as pebble layers and reaching the specified depth c of the rock layer.

[0014] S3. Horizontal pipe laying construction:

[0015] After the drilling of the heat exchange wells in a partition is completed, and the PE pipe is lowered and grouted, the horizontal pipe trench can be excavated by an excavator. The excavation width at the bottom of the trench and the excavation depth of the trench are the same as the design. Slope excavation is carried out on both sides according to the specification requirements. The specified range a at the bottom is excavated manually to prevent over-excavation. After excavating to the design elevation, lay geotextile. Each side of the geotextile extends beyond the design trench side line by a specified length. Immediately backfill fine sand with a specified thickness a after the geotextile is laid. Then install the horizontal pipe. The horizontal pipe is connected to the U-shaped pipe of the heat exchange well. Each heat exchange well is connected to a supply horizontal pipe and a return horizontal pipe. After the horizontal pipe is installed and the hydraulic pressure test is qualified, the trench can be backfilled. The specified thickness b at the top of the pipe in the horizontal pipe trench is backfilled with fine sand, and then backfilled with the original soil. After backfilling and compaction, make marks or indicate the pipeline positioning belt in the pipe laying area.

[0016] Furthermore, the excavator includes:

[0017] An excavator body for carrying out excavation work;

[0018] A leak-proof bucket for cooperating with the excavator body for excavation, through which the excavated soil can be prevented from falling back into the trench;

[0019] The leak-proof bucket includes:

[0020] A bucket body for excavating soil and providing a place for the soil to be placed;

[0021] A bucket bottom for combining with the bucket body to excavate soil;

[0022] An insertion frame connected to the top of the bucket bottom, and the insertion frame is slidably inserted into the bottom of the bucket body;

[0023] An extension component for extending the distance between the bottom of the bucket and the top of the bucket body.

[0024] Furthermore, the extension component includes:

[0025] An elastic enclosure member provided on the inner sides of the bucket body and the bottom of the bucket to connect the bucket body and the bottom of the bucket;

[0026] An installation shell symmetrically provided on one side of the bucket body;

[0027] A connecting frame slidably installed inside the installation shell, with one end of the connecting frame connected to the bottom of the bucket;

[0028] A magnet provided on the top wall of the installation shell for adsorbing and fixing the connecting frame;

[0029] A support component for supporting the side of the elastic enclosure member away from the installation shell.

[0030] Furthermore, the support component includes:

[0031] A support frame slidably installed at equal intervals from top to bottom on the inner wall of the insertion frame away from the installation shell;

[0032] A first spring connecting the side of the support frame away from the elastic enclosure member to the insertion frame;

[0033] A support bar connected to one end of the support frame;

[0034] An inclined surface provided on the bottom of the bucket body near the support bar.

[0035] Furthermore, grooves are symmetrically formed at the top of the bucket body, and an extension component for expanding the enclosure range of the side of the bucket body is provided in the grooves;

[0036] The extension component includes:

[0037] A side plate slidably arranged in the groove;

[0038] A driving component for driving the side plate to move along the groove.

[0039] Furthermore, the driving component includes:

[0040] A magnetic block connected to one side of the side plate;

[0041] A second spring connecting the magnetic block to the bottom wall of the groove;

[0042] An iron rod connected to one side of the connecting frame, with the top end of the iron rod extending into the groove and adsorbing and fixing to the magnetic block.

[0043] Furthermore, the elastic enclosure member is made of rubber, the inner upper part of the elastic enclosure member is fixedly connected to the inner wall of the bucket body, and the inner lower part of the elastic enclosure member is fixedly connected to the inner wall of the bucket bottom, and the elastic enclosure member closes the gap between the bucket body and the bucket bottom.

[0044] Furthermore, the support bar is cylindrical, and the elastic force of the first spring is sufficient to cooperate with the support frame and the support bar to support the elastic enclosure member to prevent the elastic enclosure member from sinking.

[0045] Technical effects and advantages of the present invention:

[0046] 1. The present invention effectively solves the problems of hole collapse and channeling during the drilling process of the heat exchange well of the outdoor heat exchange system of the ground source heat pump, and improves the quality of the heat exchange well. By optimizing the process and adding geotextiles, the loss of fine sand is solved, the density of the sand cushion layer and the installation quality of the horizontal pipe are guaranteed, and it has good social benefits.

[0047] 2. The present invention uses a leak-proof bucket to allow the soil that emerges from the top of the bucket to be retracted into the bucket. This prevents the soil that emerges from the bucket from being blown off by strong winds and falling back into the trench during subsequent movement of the bucket as a whole. This eliminates the need to dig out the fallen soil again, thereby improving work efficiency.

[0048] 3. The present invention provides a support assembly that supports the side of the elastic enclosure away from the mounting shell, so that the side of the elastic enclosure away from the mounting shell will not be depressed by the soil, thereby preventing the soil from obstructing the return of the bucket bottom.

[0049] 4. The present invention closes the arc-shaped openings on both sides of the bucket body by unfolding the side panels, thereby increasing the protection range on both sides of the bucket body and further improving the effect of preventing soil from falling. When the bucket bottom is reset, the side panels can be retracted and the arc-shaped openings on both sides of the bucket body can be opened, so as to meet the design requirements of the bucket itself. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It shows a process flow chart of underground pipe construction of a ground source heat pump outdoor heat exchange system according to an embodiment of the present invention;

[0051] Figure 2 A schematic structural diagram of an anti-leakage bucket according to an embodiment of the present invention is shown;

[0052] Figure 3 The cross-sectional structure diagram of the anti-leakage bucket according to the embodiment of the present invention is shown. Figure 1 ;

[0053] Figure 4 The embodiment of the present invention is shown Figure 3 A in the middle is an enlarged structural diagram;

[0054] Figure 5 shows the Figure 3 magnified structural schematic diagram at position B in

[0055] Figure 6 shows the sectional structural schematic Figure 2 ;

[0056] Figure 7 shows the Figure 6 magnified structural schematic diagram at position C in

[0057] In the figure: 1, bucket body; 2, bucket bottom; 3, insertion frame; 4, elastic enclosure member; 5, installation shell; 6, connecting frame; 7, magnet; 8, support frame; 9, first spring; 10, support bar; 11, inclined plane; 12, side plate; 13, magnetic block; 14, second spring; 15, iron rod. Specific implementation manner

[0058] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0059] The present invention provides a construction process for buried pipes of a ground source heat pump outdoor heat exchange system, including the following steps:

[0060] S1. Heat exchange well construction:

[0061] Determine the position of the heat exchange well through measurement and lofting. Before drilling, use a small top drive drill to pilot the hole to ensure the smooth rotation of the main drill, improve the verticality of the hole formation of the heat exchange well, set steel casing in soft strata to prevent cave-in. After the main drill is in place, the drill bit passes through the steel casing and continues to drill. The drill bit is provided with slurry outlet holes, and slurry is continuously transported from the slurry pit through a slurry pump, and the rock debris in the hole is carried out by the slurry; after the drilling is completed, after confirming that the designed depth is reached, use a counterweight rod to assist the vertical double U-shaped PE pipe and the grouting pipe to go down the well. The PE pipe is lowered under pressure. After the PE pipe sinks to the designed depth, the counterweight rod is recovered, and then grouting construction is immediately carried out. Wait until the slurry overflows the wellhead, and pull out the grouting pipe. After the grouting is completed, confirm that the grouting is dense and there is no cavity, and then pull out the steel sleeve; after grouting and filling, maintain pressure for 24h. When the pressure gauge does not drop significantly, the installation of the PE pipe meets the system requirements, and the pressure gauge can be removed;

[0062] S2. Pilot hole construction:

[0063] For strata such as pebble layers that are not convenient for drilling, pilot hole construction is carried out before drilling. According to the determined wellhead position, a top drive drill is used for drilling. The top drive drill is a 100-type top drive drill. The pilot hole bit uses an opening bit for the first-stage construction. The opening bit is a 172 opening bit. Drill to the specified depth a. The specified depth a is approximately 1.2 m thick. Proceed with the project to bury the steel casing. The outer diameter of the steel casing is 168 mm, the inner diameter is 152 mm, and the single length is 1.2 m. For subsequent pilot holes, an opening bit is used. The opening bit is a 146 opening bit. Bury a section of steel casing every time the specified depth b is drilled. The specified depth b is 1.2 m. The steel casing is sunk by means of hammering. The final drilling depth is subject to passing through special strata such as pebble layers and reaching the specified depth c of the rock stratum. The specified depth c is 200 mm.

[0064] S3. Horizontal pipe laying construction:

[0065] After the drilling of the heat exchange wells in a partition is completed, and the PE pipes are lowered and grouted, the horizontal pipe trench can be excavated by an excavator. The excavation width at the bottom of the trench and the excavation depth of the trench are the same as the design. Slope excavation is carried out on both sides according to the specification requirements. The specified range a at the bottom is excavated manually. The specified range a is 300 mm to prevent over-excavation. After excavating to the design elevation, a geotextile is laid. Each side of the geotextile extends beyond the design trench side line by a specified length. The specified length is 150 mm. Immediately after the geotextile is laid, fine sand with a specified thickness a is backfilled. The specified thickness a is 100 mm. Then the horizontal pipe is installed. The horizontal pipe uses a DN32 PE pipe. The horizontal pipe and the U-shaped pipe of the heat exchange well are connected by hot melt socket connection. One water supply horizontal pipe and one return water horizontal pipe are connected to each heat exchange well. After the horizontal pipe is installed and the hydrostatic test is qualified, the pipe trench can be backfilled. The specified thickness b at the top of the pipe in the horizontal pipe trench is backfilled with fine sand. The specified thickness b is 20 cm. Then the original soil is used for backfilling. After backfilling and compaction by rolling, marks are made in the pipe laying area or the positioning belt of the pipeline is marked.

[0066] I. Construction preparation:

[0067] 1. Technical preparation

[0068] 1) Familiarize with the drawings, organize the review of construction drawings, check whether the drawings are complete and complete, whether the construction drawings comply with the relevant national engineering design specifications, whether the construction drawings and the instructions are consistent in content, whether there are contradictions and errors between the construction drawings and their components, whether the coordinates, elevations and instructions are consistent, and whether the technical requirements are clear. Timely consult with the design personnel to solve problems;

[0069] 2) Do a good job in the three-level technical disclosure and safety disclosure of the project, sign and file them to ensure that the management personnel and operators are familiar with the process flow and operating procedures;

[0070] 3) Install, debug, inspect and test-run the incoming equipment and machinery to ensure normal operation of the machinery, and equip with sufficient spare parts.

[0071] 2. Site preparation

[0072] 1) For strata such as pebble layers that are not convenient for drilling, use a small excavator in advance to remove large pebbles around the heat exchange wells, and refill and compact them with qualified backfill materials.

[0073] 2) Set up a mud pit, excavate a temporary mud pit at a suitable location on the site. The setting of the temporary mud pit should cover as many drilling points as possible to meet the water intake requirements of the water pump at the end of the drill rig. Install protective railings around the mud pit to prevent people from falling. After the surrounding drilling is completed, the temporary mud pit should be cleaned up in time.

[0074] 3) Excavate a mud ditch to connect the wellhead of the heat exchange well and the mud pit to form a circulation loop with the drilling system.

[0075] II. Drilling layout and positioning

[0076] Special surveyors use a total station or theodolite to set up the well position control network, and determine the well positions one by one based on the control network. The well position error should not be greater than 5 cm, and the wellhead should be marked with wooden stakes. Mark the pipeline positioning belt above all the buried pipe points to ensure that the drilling position deviation is within 5 cm.

[0077] III. Hole formation and drilling

[0078] 1. For strata such as pebble layers that are not convenient for drilling, pilot hole construction can be carried out before drilling to ensure hole formation quality. According to the determined wellhead position, use a small top drive drill rig to drill. The drilling depth should be based on passing through special strata such as pebble layers and reaching 200 mm into the rock layer. Steel casing should be buried in sections during the pilot hole process to prevent cave-ins.

[0079] 2. Install the mud pump at the end of the drill rig. Set up a triangular bracket in the mud pit, install a chain block on the triangular bracket, hook the bottom chain to the mud pump at the end of the drill rig, slowly lift the mud pump, keep the water pump in a vertical state, and continuously adjust the position of the mud pump to ensure that the submerged depth of the mud pump meets the requirements.

[0080] 3. Before drilling operations, it is necessary to check the diameter and wear condition of the drill bit, and replace the drill bit with excessive wear in time. Select the appropriate shape, size and angle of the cutting teeth at the bottom of the drill bucket according to the soil quality.

[0081] After the drilling equipment is in place, check the drilling position, the verticality of the drill rig, and the diameter of the drill bit. Drilling can only start after confirmation. First, use a roller bit to break up the boulders remaining in the pilot hole to achieve the purpose of flushing the hole. Then, replace the button bit and continue drilling. During the drilling process, record the start and stop times and the drilling progress. Arrange for a special person to clear the rock debris floating out of the hole to one side to prevent blockage of the hole mouth.

[0082] 5. During the construction process, the drill rig should ensure the verticality of the drill pipe. During drilling, use a level to check the verticality of the drill pipe before starting the hole, when drilling to 50 meters, and before the end of the hole to avoid vertical intersection of deep holes and damage to the buried U-shaped pipes.

[0083] IV. Verification and acceptance of hole depth and hole diameter

[0084] After drilling reaches the required depth (the depth is generally 1 - 2 meters greater than the designed depth as the slurry settling section), immediately invite the supervisor to the site to check the drilling depth and hole diameter. The next process can only start after passing the inspection.

[0085] Since the depth of geothermal wells mostly exceeds 100m, it is difficult to check the drilling depth using conventional detection methods. The number of drill pipes pulled out can be counted for verification. The standard length of a drill pipe is 3m. Drilling depth = number of standard drill pipes + length of non-standard drill pipe at the top + length of drill bit at the bottom.

[0086] V. Pipe lowering under pressure

[0087] 1. The vertical U-shaped pipes in the geothermal well are DN25 PE pipes. After the PE pipes pass the on-site acceptance, stack them at the designated location.

[0088] 2. Before lowering the PE pipes, conduct the first hydrostatic test. The test pressure is 1.6 MPa, and keep the pressure stable for at least 15 minutes. After stabilization, the pressure drop should not be greater than 3%, and there should be no leakage before pipe lowering can be carried out. Release the pressure to 0.4 MPa before pipe lowering and use pressure-maintaining pipe lowering.

[0089] 3. Since there is a large amount of accumulated water in the hole after drilling, the buoyancy of the water will cause certain difficulties in placing the pipes. Therefore, use a method of manual assistance with machinery for pipe lowering.

[0090] 4. Install a counterweight rod to assist the PE pipes in descending into the well. Bind the first counterweight rod (3m long, 75kg) to the middle of 4 PE pipes using tape. Lower the wire rope of the drill rig so that the PE pipes sink with the counterweight rod. After the end of the counterweight rod sinks to the same level as the drill rig's snap ring, fix the counterweight rod with a clamp, remove the buckle connecting the top to the wire rope, install the second counterweight rod (3m long, 25kg), and then continue to lower the pipes. Repeat the above steps until the fourth counterweight rod is installed. Subsequently, continuously and smoothly lower the wire rope of the drill rig to make the PE pipes continue to sink.

[0091] 5. When the PE pipe is about 20m down the well, stop lowering the drilling rig wire rope, use tape to tie the grouting pipe and PE pipe together, and then continue to lower the wire rope to sink the grouting pipe together with the PE pipe.

[0092] 6. During the lowering of the PE pipe and grouting pipe into the well, two operators shall adjust the position of the PE pipe at any time to keep the orifice at a certain slope to prevent the heat exchange pipe from being worn or scratched during the lowering process, which may lead to a decrease in its performance.

[0093] 7. After the PE pipe is lowered to the designed depth, tighten the wire rope, lift the counterweight rod out of the well, and then remove the counterweight rod section by section.

[0094] 8. After grouting and filling, maintain the pressure for 24 hours. If the pressure gauge does not drop significantly to 0.4MPa, the PE pipe installation meets the system requirements. Only then can the pressure gauge be removed and the steel casing be pulled out.

[0095] 6. Backfilling of heat exchange well

[0096] 1. The backfill of heat exchange wells is mainly divided into pressure grouting backfill and original slurry backfill. Pressure grouting backfill is used in areas with bearing capacity requirements, and original slurry backfill is used in areas without bearing capacity requirements.

[0097] 2. Pressure grouting backfill

[0098] 1) After the heat exchanger is installed, the hole should be immediately backfilled with grouting material. The backfill grout should be a mixture of cement: fine sand: bentonite: water in a volume ratio of 5:2:1:4. Pressure grouting should be performed using an independent grouting pump (pump pressure ≥ 2 MPa). The grouting pipe diameter should not be less than De25, and the distance between the grouting equipment and the heat exchange wellhead should not exceed 15 meters. The grouting process is considered complete when the mud pump pressure is sufficient to return the mud at the bottom of the hole to the surface.

[0099] 2) During grouting, ensure continuity. The grouting tube should be gradually withdrawn according to the speed of the mechanical grouting, allowing the grouting liquid to be poured from bottom to top to seal the hole. Ensure that the drilled hole is densely grouted and free of cavities, otherwise it will reduce the heat transfer effect and affect the quality of the project. After grouting is completed, the drilling rig can be moved and inspected after 12 hours. If it is not full, manually backfill with medium-coarse sand until it is full.

[0100] 3. Backfilling with slurry

[0101] After the first well is drilled and the casing is installed, the drilling rig is removed from the wellbore, and the construction of the second well is carried out. The mud for the second well construction flows through the mud ditch to the first well, and the first well is filled by the mud passing through the first well during the mud circulation process of the second well construction. The construction of the third well is carried out repeatedly in this way. The mud ditch of the third well passes through the first and second wells, and the first and second wells are filled with the circulating mud of the third well. After 12 hours of inspection, if it is not full, the mud in the mud pit is supplemented by a mud pump, or backfilled manually with medium-coarse sand until it is full.

[0102] VII. Horizontal pipe trench excavation

[0103] A small excavator is used for horizontal excavation, with a excavation depth of 1200 - 2000mm and a width of 800 - 2000mm, which is determined according to the actual buried pipe zoning and the loop pipe alignment. Finally, manual bottom cleaning and edge trimming are adopted. Except for the reserved part stacked on the site, the surplus excavated soil is transported out of the site. A slope of three-thousandths should be set for the horizontal pipe trench, sloping towards the manifold well.

[0104] The slope setting of the pipe trench shall be carried out in accordance with the provisions of the current national standard "Code for Construction and Acceptance of Water Supply and Drainage Pipeline Engineering" GB50268 - 2008.

[0105] VIII. Horizontal loop pipe installation

[0106] 1. The horizontal loop pipe adopts DN32 PE pipe. After the PE pipe passes the on-site acceptance, it is stacked at the designated location.

[0107] 2. Before the installation of the horizontal loop pipe, first backfill 100mm thick fine sand at the bottom of the pipe trench to prevent the sharp parts of the bottom rock layer from damaging the horizontal loop pipe. For the pebble layer area, a layer of geotextile can be laid at the bottom of the fine sand to prevent the loss of fine sand.

[0108] 3. The horizontal loop pipe and the U-shaped pipe in the heat exchange well are connected by hot melt socket connection. The connection process is as follows:

[0109] 1) First, select the mold according to the specifications of the pipe to be welded, install the mold on the hot plate, adjust the heating temperature controller to the given parameter of 220℃ (±10℃), turn on the power supply for preheating, and the preheating time shall not be less than 10 minutes. The temperature adjustment shall be determined according to the ambient temperature during construction. When the ambient temperature is lower than 10℃, the heating temperature shall be appropriately increased; when the ambient temperature is higher than 30℃, the heating temperature shall be appropriately decreased;

[0110] 2) Check whether there are sundries or dirt on the surface of the mold. If there is residual polyethylene material, it should be cleaned with a wooden tool, and the surface of the mold should be wiped with clean paper or cloth to ensure the cleanliness of the mold surface;

[0111] 3) Cut the pipe according to the required length. When cutting, a special cutter must be used for vertical cutting to ensure that the cut is smooth, without burrs and flash.

[0112] 4) Before welding, wipe the inner and outer surfaces of the welding areas of the pipe and fittings with clean paper or cloth to remove impurities such as dust, moisture, and grease. The cleaning length shall be not less than 2 times the length of the pipe inserted into the fitting.

[0113] 5) Insert the end of the pipe to be welded and the fitting into the mold heated to the set temperature at the same time. After heating (the heating time is shown in Table 5.2.8-1, and the error shall be controlled within 2 seconds), quickly pull them out, and insert the welding end of the pipe into the fitting. Within a short time, adjustment within 15 degrees in the axial direction is allowed (the conversion time is shown in Table 5.2.8-1).

[0114] 6) Maintain this welding state until the cooling time (the cooling time is shown in Table 5.2.8-1). During the natural cooling process of the hot melt joint, it is prohibited to cool it with cold water.

[0115] Table 5.2.8-1 Technical Indexes of Hot Melt Socket Joint

[0116] Outer diameter of pipe (mm) Wall thickness of pipe (mm) Heating time (S) Conversion time (S) Cooling time (S) 25 2.3 6 4 7 32 3.0 7 4 8

[0117] 7) After welding, visual inspection shall be carried out. The main standards are as follows: The bead shall be uniform, smooth, and full, and the bead sizes shall be similar.

[0118] 4. In the trench, the supply pipe and the return pipe of the horizontal pipe shall be arranged separately or in layers, and shall not be laid all together.

[0119] 5. When laying the horizontal pipe, the pipe shall not wind up and down, causing air accumulation in the pipe. Instead, it shall be laid in a serpentine shape horizontally, leaving a certain space for expansion and contraction to avoid affecting the service life of the pipe due to thermal expansion and contraction.

[0120] 6. At both ends of the horizontal loop pipe, finished double-wall corrugated pipe manholes shall be set. Vertically on the top of the manhole, a DN300 double-wall corrugated protection pipe shall be set. The horizontal loop pipe passes through the finished double-wall corrugated pipe manhole and the double-wall corrugated protection pipe and is connected to the manifold. After the double-wall corrugated protection pipe is fixed firmly, backfill fine sand into the pipe.

[0121] 7. Before the horizontal pipe enters the inspection well, try to adopt the reserved method according to the actual site conditions, and directly penetrate into the inspection well later, minimizing the pipe joints as much as possible.

[0122] IX. Hydrostatic Test of Horizontal Loop Pipe

[0123] After the vertical and horizontal headers of each branch are assembled, a second hydrostatic test shall be carried out before backfilling. The test pressure is 0.6 MPa. Keep the pressure stable for at least 30 min under the test pressure. After the pressure stabilizes, the pressure drop shall not be greater than 3%, and there shall be no leakage before backfilling.

[0124] X. Backfilling of Pipe Trenches

[0125] 1. For the top 20 cm of the pipes in the horizontal pipe trench, fine sand shall be used for backfilling, and the upper part of the fine sand shall be backfilled with 30 cm of original soil. The fine sand shall be fine, loose, uniform and free of stones and soil clods.

[0126] 2. The backfilling and compaction process shall be uniform, the backfill material shall be in close contact with the pipes, and the pipes shall not be damaged. To ensure uniform backfilling and close contact between the backfill material and the pipes, the backfilling shall be carried out simultaneously on both sides of the pipes. When there are two or more rows of pipes in the same trench, the backfilling and compaction between the pipes shall be carried out symmetrically with the backfilling and compaction between the pipes and the trench wall. The pipe armpits shall be backfilled manually to ensure tight filling and ramming. When backfilling in layers for pipes, special attention shall be paid to the backfilling within 20 cm above each pipe layer. For the areas within 50 cm on both sides of the pipes and above the pipe top, light ramming shall be adopted, and it is strictly prohibited to directly apply the compaction machine on the pipes to damage the pipes.

[0127] 3. After the installation of the buried pipe heat exchanger is completed and before the upper original soil is backfilled, signs shall be made in the buried pipe area or the positioning belt of the pipeline shall be marked, and two permanent on-site targets shall be used for positioning.

[0128] Application Example:

[0129] The construction project of College A and the practice training base is located in Town B, about 150 Km away from Chengdu. The total planned land area is about 10,569.54 square meters, and the total planned construction area is 22,900.00 ㎡, of which the above-ground total construction area is 17,468.00 ㎡ and the underground construction area is 5,432.00 ㎡. The proposed buildings mainly consist of 2 multi-storey buildings and a basement, and the main structure is a frame structure. Among them, Building No. 1 has 2 underground floors (including the isolation layer) and 6 above-ground floors, with a building height of 23.95 m and an above-ground construction area of 10,470.00 square meters. The building functions are accommodation and conference. The design adopts a ground source heat pump system to bear the indoor central air-conditioning for summer cooling, winter heating and the whole-year domestic hot water demand. A total of 160 vertical buried pipe wells are designed for the outdoor heat exchange system, which are divided into two major areas. Area A has 96 wells divided into 4 small sub-areas, which are set at the bottom of the raft foundation of Building No. 1; Area B has 64 wells divided into 3 small sub-areas, which are set on the outside of the basement and the outdoor general plan.

[0130] The above project adopts this construction method, and the phenomena of hole collapse and hole channeling during the drilling process of the heat exchange wells are significantly reduced, and the construction efficiency, hole-forming quality and the one-time acceptance pass rate of drilling are significantly improved; at the same time, the compactness of the sand cushion for the horizontal buried pipes is good, the installation quality of the horizontal pipes is significantly improved, and there is no settlement or deformation after installation; the overall quality of the buried pipes in the outdoor heat exchange system of the ground source heat pump is good, with good economic and social benefits.

[0131] As Figures 2 to 7 shown, the excavator includes: an excavator body and a leak-proof bucket;

[0132] The excavator body is used for excavation work, and the anti-leakage bucket is used to cooperate with the excavator body for excavation. The anti-leakage bucket can prevent the excavated soil from falling back into the trench.

[0133] The anti-leakage bucket includes: a bucket body 1, a bucket bottom 2, an insertion frame 3, and an extension component;

[0134] The bucket body 1 is used for excavating soil and for placing the soil. The bucket bottom 2 is used to cooperate with the bucket body 1 to excavate soil. The insertion frame 3 is fixedly connected to the top of the bucket bottom 2, and the insertion frame 3 is slidably inserted into the bottom of the bucket body 1. The extension component is used to extend the distance between the bucket bottom 2 and the top of the bucket body 1.

[0135] During use, the bucket body 1 is connected to the excavator body (not shown in the figure). The excavator body drives the bucket body 1 and the bucket bottom 2 to excavate the trench. When one excavation is completed, the soil is located inside the bucket body 1 and the bucket bottom 2. At this time, the excavator body drives the bucket body 1 and the bucket bottom 2 to move, and transports the soil out of the trench. At this time, the bucket bottom 2 is below and the bucket body 1 is above. Under the action of gravity, the soil presses down on the bucket bottom 2, causing the extension component to drive the bucket bottom 2 to descend relative to the bucket body 1, extending the distance between the bucket bottom 2 and the top of the bucket body 1. At this time, due to the extension of the distance, the space inside the overall bucket formed by the bucket body 1 and the bucket bottom 2 becomes larger. At this time, the soil descends with the descent of the bucket bottom 2, causing the part of the soil that protrudes above the top of the bucket body 1 to be drawn into the bucket body 1. This prevents the soil that protrudes from the bucket body 1 from being blown off by the wind and falling back into the trench during the subsequent movement of the overall bucket, eliminating the need to re-excavate the fallen soil and improving work efficiency.

[0136] As Figure 3 and Figure 4 shown, the extension component includes: an elastic enclosure member 4, a mounting shell 5, a connecting frame 6, a magnet 7, and a support component;

[0137] The elastic enclosure member 4 is arranged inside the bucket body 1 and the bucket bottom 2 to connect the bucket body 1 and the bucket bottom 2. The mounting shell 5 is symmetrically and fixedly connected to one side of the bucket body 1. The connecting frame 6 is slidably installed inside the mounting shell 5. One end of the connecting frame 6 is connected to the bucket bottom 2. The connecting frame 6 is made of iron. The magnet 7 is fixedly installed on the top wall of the mounting shell 5 to adsorb and fix the connecting frame 6. The support component is used to support the side of the elastic enclosure member 4 away from the mounting shell 5.

[0138] During use, when the anti-leakage bucket is not in use, that is, when there is no soil inside, the position of the bucket bottom 2 is fixed by the adsorption and fixation of the magnet 7 and the connecting frame 6, avoiding the shaking of the bucket bottom 2 during the movement of the excavator body, generating abnormal noises and impacts. When the anti-leakage bucket is excavating soil inside, when the bucket body 1 is above and the bucket bottom 2 is below, at this time, under the action of gravity, the soil overcomes the suction force between the magnet 7 and the connecting frame 6, causing the bucket bottom 2 and the connecting frame 6 to descend, realizing the extension of the bucket bottom 2 relative to the bucket body 1. Among them, when the soil in the anti-leakage bucket emerges from the top of the bucket body 1, the weight of the soil at this time can cause the magnet 7 and the connecting frame 6 to separate. When the soil inside is discharged, at this time, the bucket bottom 2 is above the bucket body 1, and under the action of gravity, the bucket bottom 2 descends, and conversely, the connecting frame 6 descends, and finally the connecting frame 6 adsorbs and fixes with the magnet 7 to complete the reset of the bucket bottom 2.

[0139] When discharging the soil, the soil will fall and squeeze the side of the elastic enclosure 4 away from the mounting shell 5, causing the side of the elastic enclosure 4 away from the mounting shell 5 to be sunken, resulting in some soil getting stuck between the bucket body 1 and the bucket bottom 2. Subsequently, when the bucket bottom 2 is reset, it will hinder the reset of the bucket bottom 2, causing the bucket bottom 2 to not be able to be reset smoothly. Through the set support assembly, the side of the elastic enclosure 4 away from the mounting shell 5 can be supported, so that the side of the elastic enclosure 4 away from the mounting shell 5 will not be sunken by the soil, thereby avoiding the above situation where the soil hinders the reset of the bucket bottom 2.

[0140] As Figure 3 and Figure 5 shown, the support assembly includes: a support frame 8, a first spring 9, a support bar 10, and an inclined surface 11;

[0141] The support frame 8 is slidably installed at equal intervals from top to bottom on the inner wall of the insertion frame 3 away from the mounting shell 5. Transverse grooves matching the support frame 8 are equidistantly opened on the inner wall of the insertion frame 3 away from the mounting shell 5. The support frame 8 is slidably arranged in the transverse grooves. The first spring 9 fixedly connects the side of the support frame 8 away from the elastic enclosure 4 to the inner wall of the transverse groove on the insertion frame 3. The support bar 10 is fixedly connected to one end of the support frame 8. The inclined surface 11 is arranged on the bottom of the bucket body 1 near the support bar 10.

[0142] When the bucket bottom 2 descends, it drives the insertion frame 3, the support frame 8, and the support bar 10 to descend. When the support bar 10 descends to separate from the inner wall of the bucket body 1, the compressed first spring 9 releases its acting force and drives the support frame 8 and the support bar 10 to move towards the elastic enclosure 4, making it fit with the inner side of the elastic enclosure 4 and supporting the side of the elastic enclosure 4 away from the mounting shell 5. When the bucket bottom 2 is reset, the support bar 10 moves accordingly. After the support bar 10 abuts against the inclined surface 11, it is compressed and drives the support frame 8 to move into the transverse groove, compressing the first spring 9 and causing the support bar 10 to retract.

[0143] AsFigure 6 and Figure 7 As shown, the top of the bucket body 1 is symmetrically provided with grooves, and an extension component for expanding the side enclosure range of the bucket body 1 is provided in the grooves;

[0144] The extension assembly includes: a side plate 12, a drive assembly;

[0145] The side plate 12 is slidably disposed in the groove, and the driving assembly is used to drive the side plate 12 to move along the groove.

[0146] The driving assembly includes: a magnetic block 13, a second spring 14, and an iron rod 15;

[0147] The magnetic block 13 is fixedly connected to one side of the side plate 12, and the second spring 14 fixes the magnetic block 13 to the bottom wall of the groove. The iron rod 15 is fixedly connected to one side of the connecting frame 6, and the top end of the iron rod 15 extends into the groove and is adsorbed and fixed to the magnetic block 13.

[0148] When the bucket bottom 2 descends, the connecting frame 6 descends and the iron rod 15 descends, pulling the iron rod 15 to separate from the magnetic block 13. At this time, the compressed second spring 14 releases the force to carry the magnetic block 13 and the side plate 12 up, and finally the side plate 12 extends out of the groove, closing the arc-shaped openings on both sides of the bucket body 1, thereby increasing the protection range on both sides of the bucket body 1 and further improving the effect of preventing soil from falling. When the bucket bottom 2 is reset, the connecting frame 6 is reset, and the iron rod 15 is reset accordingly. The magnetic block 13 attracts the iron rod 15 and brings the side plate 12 back into the groove, compressing the second spring 14, so that the arc-shaped openings on both sides of the bucket body 1 are opened. Since the arc-shaped openings on the side of the bucket are not "notches", but an optimized design verified by mechanical calculations and engineering, the core goal is to find a balance between reducing resistance, improving efficiency, reducing weight, and adapting to working conditions. By retracting the side plates 12, the arc-shaped openings on both sides of the bucket body 1 are opened, so that it can meet the design requirements of the bucket itself.

[0149] like Figure 2 As shown, the elastic enclosure member 4 is made of rubber, the inner upper part of the elastic enclosure member 4 is fixedly connected to the inner wall of the bucket body 1, and the inner lower part of the elastic enclosure member 4 is fixedly connected to the inner wall of the bucket bottom 2. The elastic enclosure member 4 closes the gap between the bucket body 1 and the bucket bottom 2. The elastic enclosure member 4 can prevent soil from entering between the bucket body 1 and the bucket bottom 2, affecting the resetting of the bucket bottom 2.

[0150] like Figure 5 As shown, the support bar 10 is cylindrical, and the elastic force of the first spring 9 is sufficient to cooperate with the support frame 8 and the support bar 10 to support the elastic enclosure 4 to prevent the elastic enclosure 4 from sinking.

[0151] Working principle of the leak-proof bucket: During use, connect the bucket body 1 to the excavator body (not shown in the figure). The excavator body drives the bucket body 1 and the bucket bottom 2 to excavate the trench. When the excavation is completed once, the soil mass is located inside the bucket body 1 and the bucket bottom 2. At this time, the excavator body drives the bucket body 1 and the bucket bottom 2 to move, transporting the soil out of the trench. At this time, the bucket bottom 2 is located below and the bucket body 1 is located above. Under the action of gravity, the soil mass presses down on the bucket bottom 2, overcoming the suction force between the magnet 7 and the connecting frame 6, causing the bucket bottom 2 and the connecting frame 6 to descend, realizing the extension of the bucket bottom 2 relative to the bucket body 1. At this time, due to the extension of the distance, the space inside the overall bucket composed of the bucket body 1 and the bucket bottom 2 becomes larger. At this time, the soil mass descends with the descent of the bucket bottom 2, causing the part of the soil mass protruding from the top of the bucket body 1 to be retracted into the bucket body 1. When the overall bucket moves later, the soil mass protruding from the bucket body 1 will not be blown off by the strong wind and fall back into the trench, eliminating the need to dig out the fallen soil later and improving work efficiency. The descent of the bucket bottom 2 drives the insertion frame 3, the support frame 8, and the support bar 10 to descend. When the support bar 10 descends to separate from the inner wall of the bucket body 1, the compressed first spring 9 releases its acting force, driving the support frame 8 and the support bar 10 to move towards the elastic enclosure 4, causing them to fit against the inner side of the elastic enclosure 4 and support the side of the elastic enclosure 4 away from the mounting shell 5;

[0152] When discharging the internal soil mass, at this time the bucket bottom 2 is located above the bucket body 1. Under the action of gravity, the bucket bottom 2 descends. Conversely, the connecting frame 6 descends. Eventually, the connecting frame 6 adsorbs and fixes to the magnet 7 to complete the reset of the bucket bottom 2. When dumping the soil mass, the soil mass will fall and squeeze the side of the elastic enclosure 4 away from the mounting shell 5, causing the side of the elastic enclosure 4 away from the mounting shell 5 to dent, resulting in some soil mass getting stuck between the bucket body 1 and the bucket bottom 2. When the bucket bottom 2 is reset later, it will hinder the reset of the bucket bottom 2, causing the bucket bottom 2 to not be able to reset smoothly. By providing the support bar 10, it can support the side of the elastic enclosure 4 away from the mounting shell 5, preventing the side of the elastic enclosure 4 away from the mounting shell 5 from being dented by the soil mass, thus avoiding the above situation where the soil mass hinders the reset of the bucket bottom 2. When the bucket bottom 2 is reset, the support bar 10 moves accordingly. After the support bar 10 abuts against the inclined surface 11, it is compressed and drives the support frame 8 to move into the transverse groove, compressing the first spring 9 and causing the support bar 10 to retract;

[0153] When the bottom of the bucket 2 descends, the connecting frame 6 descends at this time, driving the iron rod 15 to descend, pulling the iron rod 15 until it separates from the magnetic block 13. At this time, the compressed second spring 14 releases the acting force, driving the magnetic block 13 and the side plate 12 to rise. Finally, the side plate 12 extends outside the groove, closing the arc-shaped openings on both sides of the bucket body 1, increasing the protection range on both sides of the bucket body 1, and further improving the effect of preventing soil from falling. When the bottom of the bucket 2 resets, the connecting frame 6 resets, and the iron rod 15 resets accordingly. The magnetic block 13 attracts the iron rod 15 to drive the side plate 12 to reset and retract into the groove, compressing the second spring 14, and opening the arc-shaped openings on both sides of the bucket body 1. Since the arc-shaped openings on the side of the bucket are not "notches", but an optimized design through mechanical calculations and engineering verification, the core goal is to find a balance among reducing resistance, improving efficiency, reducing weight, and adapting to working conditions. By retracting the side plate 12 and opening the arc-shaped openings on both sides of the bucket body 1, it can meet the design requirements of the bucket itself.

[0154] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it.

Claims

1. A construction process for ground heat exchanger pipes of a ground source heat pump outdoor heat exchange system, characterized in that: It includes the following steps: S1. Heat exchange well construction: Determine the position of the heat exchange well through measurement and lofting. Before drilling, use a small top drive drill to pilot the hole. In soft strata, set steel casing to prevent hole collapse. After the main drill is in place, the drill bit passes through the steel casing and continues to drill. The drill bit is provided with slurry outlets, and slurry is continuously pumped from the slurry pit through a slurry pump. The rock debris in the hole is carried out by the slurry; After the drilling is completed and it is confirmed that the designed depth is reached, use a counterweight rod to assist the vertical double U-shaped PE pipe and the grouting pipe to go down the well. The PE pipe is lowered under pressure. After the PE pipe sinks to the designed depth, recover the counterweight rod, and then immediately carry out grouting construction. Wait until the slurry overflows from the wellhead and pull out the grouting pipe; After the grouting is completed and it is confirmed that the grouting is dense and there is no cavity, pull out the steel sleeve. After grouting and filling, keep the pressure for 24 hours. When the pressure gauge does not drop significantly, the installation of the PE pipe meets the system requirements, and then the pressure gauge can be removed; S2. Pilot hole construction: For strata such as pebble layers that are not convenient for drilling, pilot hole construction is carried out before drilling. According to the determined wellhead position, use a top drive drill to drill. The pilot hole drill bit uses an open hole drill bit for the first section of construction, drill to the specified depth a, set up a steel casing for project establishment. For subsequent pilot holes, use an open hole drill bit, and bury a section of steel casing every time it drills to the specified depth b. The steel casing is sunk by means of hammering. The final drilling depth is based on passing through special strata such as pebble layers and reaching the specified depth c of the rock formation; S3. Horizontal pipe laying construction: After the heat exchange well drilling in a partition is completed and the PE pipe is lowered and grouted, the horizontal pipe trench can be excavated by an excavator. The excavation width at the bottom of the trench and the excavation depth of the trench are the same as the design. Slope excavation is carried out on both sides according to the specification requirements. The specified range a at the bottom is excavated manually to prevent over-excavation. After excavating to the designed elevation, lay geotextile. Each side of the geotextile extends beyond the designed trench side line by a specified length. Immediately after the geotextile is laid, backfill fine sand with a specified thickness a, and then install the horizontal pipe. The horizontal pipe is connected to the U-shaped pipe of the heat exchange well. Each heat exchange well is connected to a water supply horizontal pipe and a return water horizontal pipe. After the horizontal pipe is installed and the hydrostatic test is qualified, the trench can be backfilled. The specified thickness b at the top of the pipe in the horizontal pipe trench is backfilled with fine sand, and then backfilled with the original soil. After backfilling and compaction, make marks or indicate the pipeline positioning belt in the pipe laying area.

2. The construction process of the buried pipe of the ground source heat pump outdoor heat exchange system according to claim 1, characterized in that: The excavator includes: An excavator body for carrying out excavation work; A leak-proof bucket for cooperating with the excavator body for excavation, and the leak-proof bucket can prevent the excavated soil from falling back into the trench; The leak-proof bucket includes: A bucket body (1) for excavating soil and for placing soil; A bucket bottom (2) for combining with the bucket body (1) to excavate soil; An insertion frame (3) connected to the top of the bucket bottom (2), and the insertion frame (3) is slidably inserted into the bottom of the bucket body (1); An extension assembly for extending the distance between the bucket bottom (2) and the top of the bucket body (1).

3. The construction process of the buried pipe of the ground source heat pump outdoor heat exchange system according to claim 2, characterized in that: The extension assembly includes: An elastic enclosure member (4) provided inside the bucket body (1) and the bucket bottom (2) to connect the bucket body (1) and the bucket bottom (2); Mounting shells (5) symmetrically arranged on one side of the bucket body (1); The connecting frame (6) is slidably installed inside the installation shell (5), and one end of the connecting frame (6) is connected to the bottom of the bucket (2); The magnet (7) is arranged on the top wall of the installation shell (5) for adsorbing and fixing the connecting frame (6); The support assembly is used to support the side of the elastic enclosure member (4) away from the installation shell (5).

4. A construction process for buried pipes of a ground source heat pump outdoor heat exchange system according to claim 3, characterized in that: The support assembly includes: The support frame (8) is slidably installed on the inner wall of the insertion frame (3) away from the installation shell (5) at equal intervals from top to bottom; The first spring (9) connects the side of the support frame (8) away from the elastic enclosure member (4) to the insertion frame (3); The support bar (10) is connected to one end of the support frame (8); The inclined plane (11) is arranged on the bottom of the bucket body (1) near the support bar (10).

5. The construction process of the buried pipe of the ground source heat pump outdoor heat exchange system according to claim 4, characterized in that: Grooves are symmetrically formed at the top of the bucket body (1), and an extension assembly for expanding the side enclosure range of the bucket body (1) is arranged in the grooves; the extension assembly includes: The side plate (12) is slidably arranged in the groove; The driving assembly is used to drive the side plate (12) to move along the groove.

6. The construction process of the buried pipes of the ground source heat pump outdoor heat exchange system according to claim 5, characterized in that: The driving assembly includes: The magnetic block (13) is connected to one side of the side plate (12); The second spring (14) connects the magnetic block (13) to the bottom wall of the groove; The iron rod (15) is connected to one side of the connecting frame (6), and the top end of the iron rod (15) extends into the groove to be adsorbed and fixed to the magnetic block (13).

7. The construction process of the buried pipes of the ground source heat pump outdoor heat exchange system according to claim 6, characterized in that: The material of the elastic enclosure member (4) is rubber. The upper part of the inner side of the elastic enclosure member (4) is fixedly connected to the inner wall of the bucket body (1), and the lower part of the inner side of the elastic enclosure member (4) is fixedly connected to the inner wall of the bottom of the bucket (2). The elastic enclosure member (4) closes the gap between the bucket body (1) and the bottom of the bucket (2).

8. The construction process of the buried pipe of the ground source heat pump outdoor heat exchange system according to claim 7, characterized in that: The support bar (10) is cylindrical, and the elastic force of the first spring (9) is sufficient to cooperate with the support frame (8) and the support bar (10) to support the elastic enclosure member (4) to prevent the elastic enclosure member (4) from sagging.

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