210 results about "Insulated pipe" patented technology

The invention relates to the technical field of thermal insulation pipe hot melting welding, and particularly provides an electric hot melting welding machine for a thermal insulation pipeline joint. Comprising a hot melting welding machine and a welding auxiliary frame matched with the hot melting welding machine. Two circular rail frames; the two rotating rings are coaxially and rotatably mounted on the two circular rail frames in a one-to-one correspondence manner; the compression roller mechanism comprises four driving assemblies; a plurality of compression roller pieces are horizontally and rotationally mounted between the two driving assemblies at opposite positions on the two rotating rings; the two fastening mechanisms are assembled on the two circular rail frames in a one-to-one correspondence manner; the two groups of hot-air blowers are assembled on the two rotating rings in a one-to-one correspondence manner; the welding auxiliary frame matched with the hot melting welding machine is provided, the welding auxiliary frame has high integration, various operations before and after hot melting welding of the outer protective layer of the heat preservation pipe are met, operation is convenient and fast, standardization and normalization of welding operation of the heat preservation pipe can be improved, and the quality uniformity is improved while the welding forming quality is guaranteed.

The invention relates to the technical field of vacuum heat insulation pipes, in particular to a vacuum heat insulation pipe regulation and control method based on a self-adaptive heat flow prediction algorithm, and the method comprises the steps: S1, collecting the temperature, vacuum degree, flow and other synchronous data of a partition; s2, calculating physical quantities such as partition heat flux density; s3, constructing feature vectors and recursively updating parameters; s4, establishing a heat flow prediction model and a vacuum conduction prediction model; s5, performing joint normalization on the thermal mode residual error and the vacuum mode residual error; s6, a target partition is determined through sparse inversion, and a partition regulation and control instruction is generated; s7, cooperatively setting air exhaust, air supply, bypass and heating under the constraint; and S8, recursive least square is matched with a forgetting factor to update model parameters online. According to the method, real-time positioning is achieved under the condition that conveying is not stopped, partition abnormity is restrained, and the vacuum degree of the partition interlayer cavity and the temperature of the outer wall of the inner pipe are stably maintained in a preset working condition window.

The invention relates to the technical field of intelligent manufacturing, in particular to a plastic sleeve steel thermal insulation pipe production management method and system, and the method comprises the following steps: extracting thermal insulation pipe multi-parameter evaluation sensitivity, dynamically adjusting material injection parameters, monitoring molding data, identifying molding abnormity, outputting a control instruction, recording execution deviation, optimizing a configuration table, and generating a management record. According to the method, the thermal insulation pipe wall thickness fluctuation, the bubble body structure size and the center offset data are extracted, the response degree of each specification to the material injection parameter change is determined, the sensitive level configuration is established, the parameter adjustment precision is improved, the real-time data are collected, the change trend is calculated in combination with the target value, and the forming state is dynamically mastered; abnormal paragraphs are recognized based on time sequences and trend clustering, accurate recognition under multi-source interference is achieved, an adjustment instruction is generated in combination with deviation direction and frequency information, the material injection rhythm matching performance is improved, a dynamic regulation and control mechanism based on trend calculation and mode recognition is integrally formed, and the forming consistency and the abnormity coping efficiency are effectively enhanced.

The invention discloses a method and a device for heat preservation and decoration of an outer wall of a building. The method comprises the following steps: providing a plurality of first pipes which extend in parallel along a first direction and are fixed on the outer wall of the building, wherein the first direction is the height direction of the building; a plurality of second pipes which are connected to the first pipes in the second direction perpendicular to the first direction and fixed to the outer wall of the building are provided, so that the first pipes and the second pipes form a square frame on the outer wall of the building, and the heat preservation material is laid in the square frame to form a heat preservation layer so as to conduct heat preservation on the outer wall of the building; a hanging plate is provided, the hanging plate covers and is fixed to the square frame, and the first pipe and the second pipe are heat insulation pipes with hollow cavities. While heat preservation of the building outer wall is ensured, rain and snow water is prevented from permeating into the heat preservation layer of the building outer wall from the outside through cracks formed by cracking of the outer facade of the heat preservation layer, and cracking of the outer facade of the heat preservation layer caused by leakage and frost heaving of the heat preservation layer is further avoided.

A vacuum insulated pipe assembly 100 comprises first and second pipe sections. Each pipe section has an outer wall 120, 220 and an inner wall 110, 210 within the outer wall. The outer and inner walls

The utility model discloses the heat -preserving pipe spare with anti -skidding structure relates to pipe fitting technical field, including heat -preserving pipe main part and support, heat -preserving pipe main part is located the just above of support, heat -preserving pipe main part outside installation has anti -skidding subassembly. The utility model can effectively avoid the problem that heat -preserving pipe spare slips with using and causes interface to come off, promotes anti -skidding subassembly to slide outside heat -preserving pipe main part, makes anti -skidding subassembly move a distance, and the movable end of turnover screw rod is made into the avoidance groove, then twists screw rod and makes it along with the thread cooperation's connecting ring movement, because the position of connecting ring is restricted again and cannot produce relative movement with mounting groove, and the movable end of two mounting rings will be pulled and close to each other, then the inside clamping tooth of two is clamped into the corresponding clamping groove of two limit strips respectively, thus, mounting ring will be restricted, cannot produce relative movement with heat -preserving pipe main part, finally will be prevented the board of two mounting ring outside and is sleeved in the outside of support.

The utility model discloses an energy-saving heat exchange device of a refrigerating unit, which relates to the technical field of refrigerating equipment and comprises a first tube box, a cold fluid inlet, a cold fluid outlet and a partition plate, the upper end face of the first tube box is in circulating connection with the cold fluid inlet, and the lower end face of the first tube box is in circulating connection with the cold fluid outlet. A partition plate is welded to the middle of the first tube box, and one side of the first tube box is in bolted connection with a fixing flange. According to the energy-saving heat exchange device of the refrigerating unit, the two sides of the shell are coated with the first heat insulation pipe and the second heat insulation pipe correspondingly, the heat insulation pipes are fixed to the shell through cooperation of the first clamping plate, the second clamping plate and the fastening screw, heat loss is reduced, the energy utilization efficiency is improved, and the second pipe box on one side of the shell is in threaded fastening connection with the shell through the connecting flange; the overall sealing performance and stability of the device are guaranteed, it is ensured that the heat exchange process is efficiently carried out, then the energy-saving heat exchange function of the refrigerating unit can be effectively achieved, and the refrigerating efficiency is improved.

This invention provides an intake assembly and a compressor. The intake assembly includes an intake pipe disposed on a stationary plate, a heat insulation pipe sleeved on the intake pipe, a gap between the intake pipe and the heat insulation pipe, one end of the heat insulation pipe being disposed on the stationary plate, and the other end of the heat insulation pipe extending outside the compressor housing. According to this invention, the technical problem of overheating during intake due to the intake pipe being exposed to the high-pressure chamber gas in the prior art can be solved.

A connector for connecting a gas pipe and a heating component of a wire bonder includes a first connection end for connecting the connector to the heating component, and a second connection end for connecting the connector to the gas pipe. A heat-insulation tube is connected between the first connection end and the second connection end. The heat-insulation tube is made of a heat-insulation material and configured to insulate or reduce heat transfer between the first connection end and the second connection end. The connector may further include a first fastening sleeve for fastening the connection between the first connection end and the heat-insulation tube, and a second fastening sleeve for fastening the connection between the second connection end and the heat-insulation tube.

The utility model belongs to mechanical equipment technical field, concretely relates to an automatic candle and candle system, the automatic candle, include: candle body, high -voltage generator, metal pipe and insulating heat -proof pipe, the high -voltage generator is located in the candle body, the high -voltage generator is equipped with first electrode and second electrode, the metal pipe is located in the candle body, the top end of metal pipe protrudes the top of candle body, the metal pipe is used as gas supply line and its bottom end is connected with the first electrode of high -voltage generator, the insulating heat -proof pipe is sleeved in the metal pipe outside, the second electrode of high -voltage generator is set up in the outside of insulating heat -proof pipe, the utility model discloses through high -voltage generator, metal pipe and so on structure design, has realized the automatic ignition function of candle, need not manual use lighter or match, has improved the convenience and security of use.

The present application relates to a kind of detection systems for detecting the leak of the inner tube of vacuum insulated pipeline of test station, including the vacuum insulated pipeline for transmitting the low-temperature liquid generated by cryogenic refrigerator to distribution valve box, the vacuum insulated pipeline is connected with at least one helium mass spectrometer leak detector;Wherein, the vacuum insulated pipeline is welded by several prefabricated sections through corresponding transition section, each prefabricated section includes internal pipeline, external pipeline and vacuum interlayer between internal pipeline and external pipeline, vacuum safety plug is arranged on the external pipeline of each prefabricated section, and at least one prefabricated section is connected with an auxiliary evacuation system.The present application also relates to a kind of detection method for detecting the leak of the inner tube of vacuum insulated pipeline of test station.The present application realizes the detection of the inner tube of vacuum insulated pipeline section by section, can accurately and quickly determine the inner tube with leak, and quickly and accurately locate the leak range, improve detection efficiency and detection accuracy.

The invention discloses a vacuum heat preservation conveying pipe device and a pipeline conveying system, the pipeline conveying system comprises two conveying pipe devices, a pump and a control unit, each conveying pipe device comprises an inner pipe, an outer pipe and an electric heating structure, each inner pipe is arranged in the corresponding outer pipe, and each outer pipe is arranged in the corresponding electric heating structure. A closed cavity is formed between each inner pipe and each outer pipe, each electric heating structure surrounds each inner pipe, each inner pipe is connected and communicated, the pump pumps air in each cavity to enable each cavity to be in a vacuum state, the control unit controls the operation states of each electric heating structure and the pump, heat energy transmitted outwards through each outer pipe is reduced, and the heat energy utilization rate is improved. The inner pipe is easily kept at a default temperature, and the electric energy consumption of each electric heating structure is reduced.

The invention discloses a device and method for detecting the folding-resistant on-off stability of an FPC flat cable, and the device comprises a guide support frame which is provided with a plurality of first flat memory alloy tubes, a plurality of flat heat insulation tubes and a plurality of second flat memory alloy tubes, wherein the ports of the first flat memory alloy tubes, the flat heat insulation tubes and the second flat memory alloy tubes are sequentially and fixedly butted at intervals. The port of the first flat memory alloy pipe at one end is fixedly butted with a cold and hot air assembly for switching supply of cold and hot air; wherein two detachable resistance test interfaces are installed on the top surfaces of the two flat heat insulation pipes, and a pressing rod is installed over the second flat memory alloy pipe. According to the invention, the problems of incomplete detection coverage, low efficiency, unreal environment simulation and poor driving stability of an existing FPC flat cable folding resistance on-off stability detection device are solved.

The present invention provides a high-temperature tunnel insulation segment and a preparation method thereof, wherein the high-temperature tunnel insulation segment comprises: a concrete layer, a steel skeleton, and a plurality of triangular inserted insulation tubes; the steel skeleton is a truss structure, and the steel skeleton comprises a plurality of main bars, a plurality of double-legged stirrups, and a plurality of angled steel bars; a plurality of the main bars are arranged at intervals along the width direction of the segment, and a plurality of the double-legged stirrups are arranged at intervals along the circumferential direction of the segment, and each of the double-legged stirrups is fixed to the outside of a plurality of the main bars; a plurality of the steel bars distributed adjacently along the circumferential direction of the segment are arranged inside each of the main bars; each of the triangular inserted insulation tubes is inserted into the interior of a plurality of the main bars and is in close contact with the steel bars and the main bars. The present invention can greatly improve the insulation performance of the segment while ensuring the basic strength and impermeability of the segment.

The utility model discloses a heat preservation pipeline bearing device which comprises a bottom plate, a cushioning assembly is arranged at the top of the bottom plate, and an installation assembly is installed at the top of the cushioning assembly. The cushioning assembly comprises a cushioning base, the bottom of the cushioning base is fixedly connected with the top of the bottom plate, a damper is fixedly mounted at the top of the cushioning base, the top of the damper is fixedly connected with the bottom of the mounting assembly, a movable block is slidably connected into the cushioning base, and a connecting column is fixedly connected to the top of the movable block. The top end of the connecting column is fixedly connected with the bottom of the mounting assembly, the bottom of the movable block is fixedly connected with a spring, the bottom end of the spring is fixedly connected with a buffer pad, and the buffer pad is fixedly mounted in the cushioning base. According to the scheme, the bottom plate, the cushioning assembly and the mounting assembly are arranged, through the structure, vibration generated when a medium in the heat preservation pipeline circulates is relieved, and the effects of reducing noise and preventing parts of the bearing device from loosening are achieved.

The utility model relates to a shield constructs grouting device technical field especially is shield ground butt joint posture auxiliary control synchronous grouting device, including many grouting pipes, the grouting pipe end connection, one end of one grouting pipe is connected with grouting pump, the surface of many grouting pipes all is equipped with two heat insulation pipes, and the side contact of adjacent two heat insulation pipes, the surface of heat insulation pipe and grouting pipe surface contact is equipped with the heat conduction long hole of surface, and the both ends of two heat insulation pipes are connected through a plurality of fixed agencies, and the inside of a plurality of heat insulation pipes all is equipped with two heat medium delivery pipes, this scheme through two spliced on the grouting pipe surface heat insulation pipe, when disassembling two heat insulation pipes, need to operate fixed agency and separate between two heat insulation pipes, and convenient staff will disassemble heat insulation pipe from the grouting pipe, do not need to disassemble grouting pipe, improve the convenience of operation.

The application relates to a gas-liquid separation device, which comprises a pipe component and a heat insulation assembly. The pipe component comprises a heat exchange pipe and a flow pipe. The heat exchange pipe has a first flow channel. The flow pipe is sleeved on the outer periphery of at least part of the heat exchange pipe. The flow pipe and the heat exchange pipe have a second flow channel therebetween. The heat insulation assembly comprises a heat insulation pipe. The heat insulation pipe is sleeved on the outer periphery of at least part of the flow pipe. The heat insulation pipe and the flow pipe have a heat insulation cavity therebetween. The gas-liquid separation device has a containing cavity. The wall forming the containing cavity comprises the outer peripheral wall of at least part of the heat insulation pipe. The heat insulation assembly comprises a first sealing piece and a second sealing piece. The first sealing piece can seal one end of the heat insulation cavity. The second sealing piece can seal the other end of the heat insulation cavity. In this way, the heat exchange effect can be improved.

A vacuum-insulated pipe assembly comprises an outer pipe 120 and an inner pipe 110, concentric along a common central axis 150 to define an annular space, the space evacuated to define a vacuum. The o

A system for predicting corrosion under insulation for a network of insulated pipes, vessels, and tanks includes a corrosion modeling engine operable to receive sensor data and generate predicted rates of corrosion. The corrosion modeling engine includes a corrosion rate calculation module operable to compare an operating temperature of an insulated component to a dew point temperature of a surrounding environment to generate a predicted rate of corrosion, and a remaining life prediction module operable to generate a predicted remaining lifetime of the insulated component using the predicted rates of corrosion and on-stream inspection data. The system further includes an alarm communicatively coupled to the corrosion modeling engine and operable to alert an operator that the predicted rate of corrosion, the predicted remaining lifetime, or a combination thereof is within a pre-determined threshold.

The present invention belongs to the field of evaporators and proposes an eccentric evaporator, comprising a tank body, a discharge hopper, legs, a tank cover, a secondary steam outlet, a sensor connection port, a steam inlet, a condensate interface, a feed port, a discharge port, a control instrument, and a steam heating assembly. The discharge port is eccentrically arranged at the bottom of the discharge hopper. The steam heating assembly includes a heating well corresponding to the discharge port above and below. The exterior of the heating well is provided with a special-shaped wall sleeve that cooperates with the inner wall of the tank body. The special-shaped wall sleeve includes a cylindrical section and a fin plate group. The fin plate group includes a plurality of hollow fin plates distributed around the heating well. A condensation port is provided at one end of the hollow fin plate facing the center of the heating well. A condensate outlet pipe, an insulation pipe, and a drainage pipe are provided on the outlet side of the condensate outlet. The output end of the drainage pipe is connected to the condensate interface. The present invention has a reasonable design, a simple structure, can make the material flow in a sheet film, is conducive to improving heat transfer efficiency, has a good discharge effect, and has a high comprehensive utilization rate. It is suitable for large-scale promotion.

This invention discloses a core holder and experimental method for thermal stress fracturing experiments, comprising: an insulated pipe kit having a through cavity; a heating device at one end of the insulated pipe kit, and an insulation layer in the area outside the heating device; a first temperature sensor on the upper side of the area opposite the insulation layer, and a transparent glass-encased steel container on the lower side of the area opposite the insulation layer; a second temperature sensor on the heating device; a clamping device for clamping the insulated pipe kit; a piston kit disposed on the clamping device for introducing gas or liquid into the cavity of the insulated pipe kit; and a device for clamping the experimental core placed in the cavity of the insulated pipe kit. This experimental apparatus, in addition to thermal stress fracturing displacement experiments, can also meet the equipment requirements of conventional body experiments, exhibiting strong functionality.

The utility model discloses a heat preservation and insulation pipeline joint sealing connection structure which comprises a polyurethane heat preservation pipeline, sealing connection assemblies are arranged at the two ends of the polyurethane heat preservation pipeline, and the outer sides of the sealing connection assemblies are wrapped with buckling type heat preservation assemblies. After the ends of the adjacent polyurethane heat preservation pipelines are centered, the sealing gasket and the pressing ring are installed in place, the flange plate on one side is rotated so that the flange plates on the two sides can be aligned, the flange plates on the two sides are fixedly connected through the bolt connecting piece, and in the fastening process of the bolt connecting piece, the annular sleeve seat extrudes the rubber sealing gasket and the limiting ring seat; therefore, the pressing ring is in close contact with the sealing gasket, the mechanical sealing effect of the pipeline joint position is achieved, the buckling type heat preservation assembly wraps the outer portion of the connecting position, and the heat preservation and heat insulation effect of the combination position between the polyurethane heat preservation pipelines can be further improved.

This utility model provides a polyurethane insulated pipe with pipe supports, belonging to the field of insulated pipe technology. It addresses the problem that existing polyurethane insulated pipes with pipe supports require disassembly and repositioning of the pipe supports when their installation position is incorrect, which is cumbersome and inefficient. The new design includes two fixed uprights, both fixedly connected to the upper surface of a base; two sliding uprights, each slidably connected to the inner side of the two fixed uprights; a fixed pipe support fixedly connected to the upper end of the two sliding uprights; a hinged pipe support hinged to the upper end of the fixed pipe support; and an insulation sleeve positioned on the upper end of the fixed pipe support. This design enables easy installation and adjustment of the pipe support, improving adaptability and reliability, and reducing the labor intensity of construction workers.

The invention provides a multi-layer heat insulation pipeline used for conveying gas. The multi-layer heat insulation pipeline used for conveying first gas comprises an inner pipeline and an outer pipeline. The first gas is conveyed in the inner pipeline in the gas extraction direction. The inner pipeline is provided with a plurality of through holes. The inner pipeline is arranged in the outer pipeline. The outer pipeline comprises an air inlet pipe. The second gas is firstly heated or cooled and then is injected into the outer pipeline from the gas inlet pipe. The second gas is non-reactive with respect to the first gas. The first pressure of the first gas is less than the second pressure of the second gas.

The invention belongs to the technical field of heavy oil thermal recovery, and discloses a packer suitable for heavy oil thermal recovery, a nitrogen composite heat insulation pipe column and an implementation process. The packer and nitrogen composite heat insulation pipe column comprises a constant pressure valve, a thermal recovery packer, a check valve, a compensator and a heat insulation oil pipe. In order to solve the problems of limitation of a thermal insulation technology of an existing thickened oil thermal production well, limited thermal insulation effect of a packer and the like, thermal insulation of the packer is combined with a nitrogen thermal insulation technology, a tubular column structure utilizing the thermal production packer, a check valve, a constant pressure valve and a thermal insulation oil pipe is designed, and a continuous and efficient thermal insulation process method is formed by matching with nitrogen injection. Longer-time intermittent injection of nitrogen can be achieved, the steam injection heat insulation effect is effectively improved, and meanwhile the nitrogen consumption can be reduced.

The utility model discloses a thermal insulation pipeline repairing device, which relates to the technical field of thermal insulation pipeline repairing, and comprises an upper protection plate, upper fixing blocks fixed on two sides of the upper protection plate, upper L-shaped blocks fixed at the bottoms of the upper fixing blocks, a lower protection plate, lower fixing blocks fixed on two sides of the lower protection plate, and sliding grooves formed in the lower fixing blocks. A lower L-shaped block is arranged in a sliding groove, a bolt is rotated, the bolt enters a notch, the sliding block can move downwards, then the lower L-shaped block drives an upper L-shaped block to enter the sliding groove, an upper protection plate and a lower anti-skid plate are tightly attached, and the fixing function of the upper protection plate and the lower protection plate is conveniently completed in a narrow space; and meanwhile, an inserting block at the bottom of the upper protection plate is inserted into an inserting groove in the lower protection plate, the upper protection plate slides, so that an upper L-shaped block is inserted into a lower L-shaped block, and the situation that transverse limiting is lacked, and the upper protection plate and the lower protection plate are staggered is avoided.

The application relates to a washing machine inlet and drain pipe and a control method thereof and a washing machine, the inlet and drain pipe comprising a water inlet pipe, a heat storage layer, a drain pipe and a heat insulation pipe; the heat insulation pipe is attached to the drain pipe and can realize heat exchange with the drain pipe; the heat storage layer is attached to the heat insulation pipe and can realize heat exchange with the heat insulation pipe; the water inlet pipe is attached to the heat storage layer and can realize heat exchange with the heat storage layer; the heat insulation pipe can be filled with heat exchange liquid or air; when the heat insulation pipe is filled with heat exchange liquid, the heat insulation pipe can realize heat exchange with the drain pipe; when the heat insulation pipe is filled with air, no heat exchange or reduced heat exchange efficiency is realized between the heat insulation pipe and the drain pipe; the scheme can effectively reduce energy consumption caused by heating during washing, reduce heating time of heated washing or heated rinsing, reduce detergent residues on clothes during cold water rinsing, and improve washing and rinsing efficiency.

The utility model provides a port trimming device for a direct burial thermal insulation pipe, which relates to the technical field of direct burial thermal insulation pipes, and comprises a rack, the rear surface of the rack is fixedly connected with a mounting rack, the rear surface of the mounting rack is fixedly connected with a first motor, and the output end of the first motor rotatably penetrates through the outer surface of the mounting rack. When the trimming device is used, the direct burial thermal insulation pipe to be trimmed is stably placed between the first arc-shaped block and the second arc-shaped block, the trimming end face of the direct burial thermal insulation pipe is perpendicular to the contact face of the friction block, when the first motor drives the mounting plate to move forwards, the second motor is synchronously started, and the output end of the second motor drives the rotating disc to rotate at a high speed; through the arrangement of the friction block, burrs or protrusions on the end opening face of the friction block are rapidly removed when the friction block gradually makes contact with the end opening of the directly-buried thermal insulation pipe till the surface is smooth and perpendicular, the friction trimming effect is achieved, the grinding and trimming speed is high, tools do not need to be used for reference measurement in the trimming process, and the trimming efficiency of the directly-buried thermal insulation pipe is improved.

This invention discloses a deployable fire-operated slotting device, comprising a deployable fire-operated slotting nozzle and a gas pipeline, which are connected by a heat-insulating hose. The fire-operated slotting nozzle includes two parallel semi-circular heat-insulating tubes, the tails of which are connected to the gas pipeline via heat-insulating hoses. A sleeve is provided on the rear half of the semi-circular heat-insulating tubes and the outer side of the heat-insulating hoses. A horizontally arranged pin and steel wire rope are welded inside the sleeve. In the borehole, the fire-operated slotting nozzle moves the sleeve backward by pulling the steel wire rope, releasing the two semi-circular heat-insulating tubes and the heat-insulating hoses from the sleeve's constraint. The two semi-circular heat-insulating tubes unfold under the traction of the spring and the steel wire rope, forming a T-shaped structure. After ignition and with dragging, it can achieve directional fire-operated slotting in the borehole, forming a wider slot, thereby obtaining a larger free surface in the coal seam, reducing drilling volume, and improving pressure relief.

The utility model discloses a furnace wall preheating device of a copper alloy smelting furnace. The furnace wall preheating device comprises a hanging ring arranged on the top face of a sealing cover plate, a heat insulation pipe A is vertically arranged in the center of the bottom face of the sealing cover plate, a telescopic rod A is arranged in the heat insulation pipe A in a sliding mode, and a first telescopic cylinder capable of driving the telescopic rod A to slide in the vertical direction is arranged in the heat insulation pipe A; a plurality of heat insulation pipes B are arranged in the circumferential direction of the outer walls of the heat insulation pipes A and the telescopic rods A at equal intervals, telescopic rods B are slidably arranged in the heat insulation pipes B, and second telescopic cylinders capable of driving the telescopic rods B to horizontally slide are arranged in the heat insulation pipes B; the tail ends of the telescopic rods B on the heat insulation pipe A are fixedly connected with upper heating plates, and the tail ends of the telescopic rods B on the telescopic rods A are fixedly connected with lower heating plates; the preheating device has the advantages of being high in heating efficiency, capable of preheating smelting furnaces with different inner cavity sizes, reducing the cold start time of the smelting furnace, reducing moisture absorption of the furnace wall during long-time placement, simple in structure, low in cost and the like.