299 results about "Double tube" patented technology

The utility model relates to the technical field of pipe cutting devices, in particular to an automatic cutting device for a three-way pipe fitting. According to the technical scheme, the device comprises a base, a sliding table is slidably mounted at the top of the base, a single-pipe-head clamping plate is fixedly mounted at the top end of the sliding table, a protective baffle is fixedly mounted on the side, away from the sliding table, of the top of the base, a transverse moving frame plate is slidably mounted at the top end of the sliding table, and a first rubber column head is clamped and inserted into the transverse moving frame plate; a double-pipe-head clamping assembly is fixedly installed at the top end of the base, two clamping plates are arranged on the double-pipe-head clamping assembly, and second rubber column heads are fixedly installed on the inner side walls of the clamping plates. By means of the single-pipe-head clamping plate and the double-pipe-head clamping assembly, any port of the three-way pipe can be clamped and fixed, the pipe positioning difficulty is reduced, the rubber column heads support the inner walls of the pipe heads, the deformation probability during pipe cutting can be reduced, cutting is convenient, and the production efficiency is effectively improved.

A fluid damper having a damper housing with a first and a second fluid volume, and a damping piston located within the damper and separating the first and second fluid volume. The damper piston has a piston fluid pathway formed therethrough and between the first and second fluid volume. The fluid damper includes a fluid accumulator having a pressurizable gas volume and an accumulator fluid volume isolated from one another by a separation member. The fluid damper has a first fluid pathway extending solely between the first fluid volume and the accumulator fluid volume, and the fluid damper has a second fluid pathway extending solely between the second fluid volume and the accumulator fluid volume. A flow control valve is located in at least one of the first and the second fluid pathways, and the flow control valve has a non-zero threshold value.

A fluid damper having a damper housing with a first and a second fluid volume, and a damping piston located within the damper and separating the first and second fluid volume. The damper piston has a piston fluid pathway formed therethrough and between the first and second fluid volume. The fluid damper includes a fluid accumulator having an accumulator fluid volume. The fluid damper has a first fluid pathway extending between the first fluid volume and the accumulator fluid volume, and the fluid damper has a second fluid pathway extending between the second fluid volume and the accumulator fluid volume. A flow control valve is located in at least one of the first and the second fluid pathways, and the flow control valve has a non-zero threshold value.

The invention discloses a fastening device for water conservancy and hydropower construction, relates to the field of water conservancy and hydropower construction auxiliary equipment, and aims to solve the problems of low pipeline butt joint precision, difficulty in parallelism control and poor distance adjusting efficiency in the existing two-group double-pipe parallel construction. The device comprises a bottom plate, a mounting frame, a sliding device, an adjusting device, a clamping device and a control panel, and buffer springs are arranged in supporting legs of the mounting frame. The adjusting device drives the clamping assembly through the bidirectional threaded rod, and coaxiality control over segmented splicing of the long pipeline is achieved. The sliding device is matched with an electric push rod through a sliding rail, and the parallel distance between the two spliced long pipes is adjusted in an electric control mode through a control panel. The device adapts to various common pipe diameters, can be assembled and disassembled by a single person, is stable in fixation, can resist construction vibration and pressure, conforms to related specifications, remarkably improves the construction efficiency, reduces the equipment cost, and is suitable for cooling pipes, water supply pipes, grouting pipes and other scenes.

The invention discloses a heat pump type efficient dehumidification device with a waste heat recovery function, and belongs to the technical field of efficient dehumidification devices. A temperature locking cavity is formed in the center of the interior of a dehumidification base, a first hot-pressing dehumidification box and a second hot-pressing dehumidification box are symmetrically arranged at the two ends of the temperature locking cavity, heat pump storage boxes are arranged at one ends of the hot-pressing dehumidification boxes side by side, and a flow guide center frame is arranged in the center of the interior of the second hot-pressing dehumidification box; the device has the remarkable advantages that firstly, a high-temperature primary dehumidification and low-temperature secondary dehumidification grading mode is adopted, the design of a zigzag flow channel and a symmetrical cavity is matched, the dehumidification efficiency is high, continuous operation can be kept during cavity dehydration, and constant temperature and low humidity of the environment are ensured; secondly, a whole-process waste heat utilization system is constructed, cold water is converted into hot water through cold water spraying, heat exchange arc piece circulation and the like, meanwhile, waste heat of a temperature locking cavity is recycled, and energy waste is reduced; and hot water and waste water are treated in order through the double-pipe hot drain valve, and environmental protection and economical efficiency are both considered.

The invention provides a double-pipe self-locking type gas spring and relates to the technical field of double-pipe self-locking type gas springs, the double-pipe self-locking type gas spring comprises a sleeve, a lubricating structure, a connecting structure and a safety structure, a sliding rod is installed on the inner wall of the sleeve, a connecting piece is arranged at the end, away from the sliding rod, of the sleeve, and a connecting piece is arranged at the end, away from the sleeve, of the sliding rod; the connecting piece and the joining piece are connected with the sliding rod and the sleeve respectively through connecting structures, and a lubricating structure is arranged at the upper end of the sleeve. The problems that when a double-pipe self-locking type spring is used, a lubricating device is arranged in the double-pipe self-locking type spring, but in the actual using process, lubricating oil is troublesome to add and replace, continuous and stable lubrication of sliding parts in the double-pipe self-locking type spring is difficult to achieve, and the service life of the double-pipe self-locking type spring is affected are solved. The problem that the normal use and the service life of the double-tube self-locking spring are affected due to the fact that the sliding rod and the sleeve are prone to being blocked and even abraded due to the fact that friction is too large is solved.

The invention discloses a double-pipe drilling double-power drilling machine system, which belongs to the technical field of drilling rods, and comprises an outer drilling rod, a spiral inner drilling rod is rotatably arranged in the outer drilling rod, the outer drilling rod is in threaded connection with a pipe drill bit, a PDC drill bit is arranged at one end, far away from the outer drilling rod, of the pipe drill bit, and a plurality of liquid holes are formed in the PDC drill bit; a composite slice drill bit is arranged on the periphery of the end, away from the outer drill rod, of the pipe drill bit, and a deslagging channel is formed between the composite slice drill bit and the PDC drill bit. And a central channel communicated with the liquid hole is formed in the central position of the spiral inner drill rod. According to the double-pipe drilling and double-power drilling machine system, scour and damage of drilling cuttings to a drilling hole wall are fundamentally eradicated, the drilling cuttings carrying efficiency of a medium is greatly improved through the spiral stirring and vortex effect generated by reverse rotation of the inner drill pipe and the outer drill pipe, the stubborn problem that a slag discharging channel is blocked is effectively solved, and the service life of the drilling cuttings is prolonged. And continuous and efficient operation under complex and deep hole working conditions is ensured.

An ultrasonic liquid level sensor probe using a piezoelectric plate FPC module which has a simple configuration, is small and easy to handle, requires no wiring of lead wires, and is easily assembled into a probe. For the piezoelectric plate FPC module, there are a single-sided arrangement, in which an FPC is bonded to one-side surfaces of two or more piezoelectric plates, and a double-sided arrangement, in which two or more piezoelectric plates are sandwiched between two FPCs that are an FPC for individual electrodes and an FPC for a common electrode. The ultrasonic liquid level sensor probe has the piezoelectric plate FPC module stored in a double pipe serving as an insertion portion of the ultrasonic liquid level sensor probe.

The utility model belongs to heat exchanger technical field, concretely relates to a heat exchanger double tube plate welding structural member. Heat exchanger double tube plate welding structural member includes: the tube side tube plate is provided with the boss at the right end part of the tube side board tube, is provided with the boss ring main part at the left end part of the shell side tube plate, is provided with the boss ring step at the left end part of the boss ring main part, the right end surface of the boss is with the left end surface of the boss ring main part coaxial contact, the inner side surface of the boss ring step is with the outer side surface of the boss adapts, the outer side surface of the boss ring step and the outer side surface of the boss are the welding position.

The invention provides a double-pipeline laying method capable of welding while construction, which belongs to the technical field of marine oil and gas engineering and comprises the following steps: step 1, executing a dynamic welding and double-pipeline collaborative laying method; 2, executing a mechanical and deformation control method of the pipeline structure; and step 3, executing the land-sea collaborative operation and partition management and control method. The defect that in the prior art, due to the fact that the working space of a pipe laying ship is relatively narrow, the high-efficiency and high-quality double-pipe welding requirement is difficult to meet through traditional welding equipment and technology is effectively overcome.

The application discloses an adjustable double-pipe welding table, which comprises a table top, a supporting frame, an adjusting device and a to-be-welded part positioning device, the to-be-welded part positioning device is installed on the table top, the to-be-welded part positioning device can stop and position each to-be-welded part, the table top is hingedly arranged on the supporting frame and can rotate around a horizontal rotating shaft, and the adjusting device can stop and position the table top and the supporting frame which are rotated to any angle, the to-be-welded part can be opposite to different welding directions through the rotation of the table top around the horizontal rotating shaft on the supporting frame, and the worker can accurately weld all welding positions of the part without changing the welding position around the to-be-welded part during the welding process, the to-be-welded part positioning device can accurately position the upper pipe, the lower pipe and the connecting plate in all directions, the synchronous welding of multiple parts of the cantilever can be realized at one time, the welding efficiency is high, there is no repeated positioning error, and the welding precision is high.

The application relates to a double-pipe booster which comprises a container body and a boosting piece, and relates to the technical field of oral care products and auxiliary equipment thereof. The container body comprises at least two pipe bodies, the multiple pipe bodies are arranged in parallel and side by side, the adjacent two pipe bodies are fixedly connected, one end of the pipe body is a discharging port, and the other end is a pushing port; a sliding seat is arranged in each pipe body, the outer wall of the sliding seat is attached to the inner wall of the pipe body, and the sliding seat is slidingly connected to the pipe body along the pipe length direction of the pipe body; the boosting piece is arranged correspondingly to the pipe body, the boosting piece slides in parallel to the pipe length direction of the pipe body, the multiple boosting pieces are arranged in parallel and at intervals, the adjacent two boosting pieces are fixed through a first connecting piece, so that the adjacent two boosting pieces have a gap, one end of each boosting piece is located in the pipe body and slides along the pipe length direction of the pipe body, and one end of the boosting piece abuts against one side of the sliding seat close to the pushing port. The application has the effects of improving product proportioning accuracy and being simple to operate.

The present invention provides an inner pipe support unit having a brace of a leaf spring structure for supporting an inner pipe disposed in an inner space of an outer pipe constituting a double pipe that may be provided in a gas transfer system or the like of a ship using LNG, LPG, or the like as fuel gas. The inner pipe support unit for a double pipe according to the present invention, as described above, provides: 1) a structure in which a pair of braces surrounding the inner pipe are connected by direct wide-area surface contact in a predetermined area range; 2) a structure in which the pair of braces are fastened to each other by bolts and nuts coupled to each other outside the braces through fastening holes formed only on both ends of fastening guides having a width greater than that of the braces; and 3) a structure in which the pair of braces surround the inner pipe with a pair of bushings disposed therein. Accordingly, structural stability and material mechanical stability are maximized, deformation / cracking / twisting / fatigue failures are minimized / suppressed by high durability, and manufacturing / assembly / installation works are facilitated.

The invention discloses a double-pipe drilling tool synchronous loading and unloading device and a loading and unloading method. The device comprises a manipulator, a rotary positioning mechanism, a clamp combination body and a power head, the manipulator is arranged on the side of the drilling mast and connected with the frame; the manipulator is composed of a gripper and a movable arm, the gripper is composed of a movable clamping block and a fixed clamping block, and a sleeve clamping block and a drill rod clamping block are arranged in the gripper and connected through bolts; the movable arm is connected with the fixed arm through the rotary oil cylinder; the rotary positioning mechanism consists of a thrust plate, a manipulator platform and a rotary speed reducer; the manipulator platform comprises a manipulator platform mounting plate and a mounting base fixed on the frame; the rotary speed reducer is fixed on the manipulator platform; a movable ring of the rotary speed reducer is in bolted connection with the manipulator fixed arm base; the clamp combination body comprises a lower clamp, a middle clamp and an upper clamp; the power head is limited through the power head drilling mast rail groove and slides up and down along the drilling mast; the pipe joint is of a structure suitable for a double-pipe drilling tool. By means of the device, personnel do not need to make direct contact with the drilling tool, and the accident rate is reduced.

This invention discloses a double-layer steel-tube concrete column and its construction method in the field of concrete-steel tube column technology, which can guide the force. It includes an outer protective tube, a ribbed inner tube, a reset tie rod, and a concrete column. The outer protective tube and the ribbed inner tube form a double tube, and the bearing capacity and stiffness of the concrete-steel tube column are actively controlled by the thickness difference between the connecting tube and the outer protective tube. The double tube achieves a double-gradient constraint effect, achieving the purpose of controllable damage and controllable plasticity. This makes the order of the column's plastic hinge reasonable. At the same time, a longer reset tie rod is set locally, and the reset rib is formed by the superelasticity of the material. This enables the column structure to self-reset after being shaken. Moreover, the construction method is simple, and the repair is simpler when the column is slightly damaged.

The invention discloses a double-transistor flyback circuit control method, circuit and chip, and the method comprises the steps: a drive controller detects whether a drive power supply of a first switching tube needs to be forcibly charged, if yes, a second pin is controlled to output a high level, and if not, a second pin is controlled to output a high level; the second pin is controlled to charge a driving power supply of the first switch tube through a power supply connected with the third pin, after charging is completed, the second pin is controlled to output a low level, otherwise, the second pin and the first pin are controlled to output a high level at the same time, so that the second switch tube and the first switch tube are turned on at the same time; when a signal for turning off the switching tube is detected, the first pin is controlled to output a low level to turn off the first switching tube, and the second pin is controlled to output a low level to turn off the second switching tube after waiting for a first preset time.

The utility model provides a vertical double -tube -pass sulfur condenser, it includes: base, cylinder, heat exchange tube, wherein the cylinder vertical connection is in the base top, the base is divided into double -chamber through the partition, the heat exchange tube is accomodate in the inner chamber of cylinder, and its both ends are intercommunicated with the both sides chamber in the base respectively, the cylinder is equipped with the cooling medium import, steam export respectively with its inner chamber intercommunication, first side chamber of double -chamber is equipped with process gas import, first steam import, first condensate water export, first liquid sulfur export respectively, second side chamber is equipped with process gas export, second steam import, second condensate water export, second liquid sulfur export respectively. By this, through vertical double -tube -pass structure design, reduce the floor area, save the site resources effectively, benefit the compact layout of equipment, optimize the whole technological process.

This invention discloses a powder material weighing and metering device and method, relating to the field of powder material weighing technology. The invention includes a frame, a top box, a storage tank, a movable seat, a discharge pipe, and a feeding platform. The top box is fixed to the top of the frame, the movable seat is fixed to the periphery of the frame, the storage tank is fixed to the movable seat, and the discharge pipe is fixed to the bottom of the storage tank with screws. The feeding platform is fixed to the periphery of the frame directly below the movable seat. The storage tank of this invention can be assembled into a single tank or a double tank. In the single tank configuration, the mixing shaft is integrated through a specific first plate, suitable for single-pipe discharge scenarios. In the double tank configuration, a second plate with a partition is used, and the mixing shaft is used separately on both sides, achieving dual-pipe discharge. Both tanks can be loaded with the same or different powder materials for weighing and metering. Furthermore, when used in a dual-station configuration, both stations can be used simultaneously or independently, meeting different production needs.

The utility model discloses an easy-to-control fish controller which comprises a supporting pipe fitting, a spring locking piece and a clamping piece assembly, and the spring locking piece is installed on the supporting pipe fitting and can slide in the longitudinal axis direction of the supporting pipe fitting; the clamping piece assembly is rotationally installed on the supporting pipe fitting through the spring lock catch piece. The top end of the clamping piece assembly is opened by pushing the spring locking piece upwards, and the top end of the clamping piece assembly is closed under the action of downward resilience force of the spring locking piece. The fish controller is compact in structure, the spring piece slides up and down to control the first clamping piece set to move, then the top end of the second clamping piece set is controlled to be opened and closed, the overall controllability is better, the first clamping piece set and the second clamping piece set form an 8-shaped structure in the closed state, the design of double-pipe nesting is adopted, and the fish controller is convenient to use. The rigidity on the longitudinal axis is higher, and the overall stability is higher.

The utility model discloses a weighing structure of a double-tube vertical thermogravimetric atmosphere furnace, relates to the technical field of vertical atmosphere furnaces, and aims to solve the problems that when an existing vertical atmosphere furnace is used and materials after reaction are weighed, the materials can only be taken out, so that the operation is tedious and inconvenient. The vertical atmosphere furnace comprises a vertical atmosphere furnace body, an inner cavity is formed in the vertical atmosphere furnace body, a telescopic rod body is arranged in the inner cavity, an outer fixed connecting support is arranged on the lower side of the outer wall of the telescopic rod body, and a vertical rod mechanism is arranged at one end of the outer fixed connecting support and detachably connected with the outer fixed connecting support in a threaded mode.

The invention provides an arc-shaped cutting blade type double-pipe shallow undisturbed soil sampler. The arc-shaped cutting blade type double-pipe shallow undisturbed soil sampler comprises an outer sleeve, an inner sleeve soil sampler, an arc-shaped cutting blade and an annular drill bit, a rotary drilling disc is arranged at the upper end of the outer sleeve, and an annular drill bit is arranged at the lower end of the outer sleeve. The inner sleeve soil sampler is arranged in the outer sleeve through a rotating rolling shaft; a downward-pressing vertical rod is arranged between the inner wall of the outer sleeve and the outer wall of the inner sleeve soil sampler, one end of the downward-pressing vertical rod extends out of the outer sleeve, and the other end of the downward-pressing vertical rod is used for being hinged to the arc-shaped cutting blade; the inner diameter of the annular drill bit is larger than the outer diameter of the inner sleeve soil sampler and smaller than the inner diameter of the outer sleeve; chamfers corresponding to cutting edges of the arc-shaped cutting blades are arranged on the inner wall of the joint of the annular drill bit and the outer sleeve. According to the soil sampler, the outer sleeve can rotate while the inner sleeve soil sampler is immovable, and interference on undisturbed soil can be effectively reduced. And the undisturbed soil at the lower opening of the soil sampler can be quickly cut.

The invention discloses a wine taking needle and a wine taking machine, and the wine taking needle comprises a needle body and a shell; the needle body is of a double-layer structure and comprises an inner core and an outer sleeve which are isolated from each other, the inner core is provided with a first opening, and the outer sleeve is provided with a second opening; the shell covers and is fixed at one end of the needle body, and an air guide channel and a liquid guide channel are arranged in the shell; the air guide channel is communicated with the inner core through the first opening, and the liquid guide channel is communicated with the outer sleeve through the second opening; the gas guide channel and the liquid guide channel extend to the bottom face of the shell so as to form a gas conveying opening and a liquid taking opening correspondingly, and self-plugging pieces are arranged at the gas conveying opening and the liquid taking opening correspondingly. The needle body is composed of the inner core and the outer sleeve in a sleeved mode, the inner core and the outer sleeve are integrated and share the outer sleeve puncture wooden plug, double-needle wine taking is achieved in a single-needle insertion mode, bottle opening is not needed in the process, air can be isolated for wine taking, the needle body of the double-layer structure forms the gas conveying system and the wine taking system which are mutually isolated and matched, and the wine taking effect is good. And the wine taking process is stable and rapid in flow and convenient to meter.

This utility model belongs to the field of pipe manufacturing technology, specifically relating to an expansion joint device for double-expansion spiral pipes, including a clamping die assembly, a punching die assembly, and a connecting assembly. The clamping die assembly is used to clamp the pipe fitting and the flange to be expanded. The punching die assembly includes an expansion sleeve and an expansion core movably disposed within the expansion sleeve. The end of the expansion sleeve is provided with an expansion tube end, and the expansion core can move axially within the expansion sleeve to expand the expansion tube end. The shape of the expansion tube end is adapted to the shape of the pipe fitting expansion position. The expansion core is connected to the connecting assembly. The connecting assembly is used to connect to a power mechanism. This utility model achieves synchronous expansion joint of two pipes, avoiding the processing interference problem caused by step-by-step operation, significantly improving production efficiency. At the same time, this utility model has a compact structure, is easy to operate, reduces process complexity, and reduces production costs.

The invention relates to the technical field of chemical equipment structures, in particular to a compact type loosening integrated station for catalytic cracking, which comprises a trunk pipeline of a U-shaped integrated structure; the main conveying pipe column is formed by connecting a plurality of first branch pipes extending in the vertical direction in parallel, and the two ends of each first branch pipe are communicated with the main pipeline; the auxiliary dredging pipe array and the main conveying pipe array are connected in parallel and share the main pipeline; the second branch pipe is led out from the side direction of the first branch pipe and forms a user end interface; wherein the main conveying pipe array, the auxiliary dredging pipe array and the second branch pipe are integrated in a three-dimensional arrangement mode. According to the invention, through highly integrated structural design and main and auxiliary double-tube array configuration, the problems of large occupied space, complex operation, weak emergency capability and the like of a traditional system are effectively solved.

1. Name of the product in this design: Dual-tube applicator. 2. Purpose of this design: A specialized device for delivering radiation sources to the target area in brachytherapy. 3. The key design feature of this product is its shape. 4. The image or photograph that best illustrates the design's key points: a 3D model.

The invention discloses a synchronous rectification leading edge blanking self-adaptive adjustment method adaptive to double-transistor flyback. The method comprises the following steps: detecting the turn-on time of a driving signal of a synchronous rectification controller and the high level time of a high-voltage detection signal; calculating a first duty ratio and a second duty ratio; judging whether a leading edge blanking time self-adaptive adjustment closed-loop condition is met or not; when the turn-on time of the driving signal is increased and is close to the high level time of the high-voltage detection signal, adjusting is stopped, and the current leading edge blanking time is maintained; and if the turn-on time of the driving signal is not increased to be greater than the leading-edge blanking time after the leading-edge blanking time is adjusted by the synchronous rectifier within the preset time range, the leading-edge blanking time is traced back to a default value. According to the method, the leading edge blanking algorithm is optimized in the synchronous rectification controller, so that the change of system power parameters is avoided to the greatest extent, the design complexity of a power supply system is reduced, and the risks of efficiency reduction and temperature rise and heating caused by repeated design and mistaken starting of the system are avoided.

The utility model relates to a kind of for the guide of double cylinder shock absorber and the shock absorber, the guide component includes guide unit and oil scraper ring, guide unit includes first annular step portion, second annular step portion and third annular step portion sequentially along first axial end to second axial end arrangement, three gradually reduce and transition are connected with inside diameter;Guide unit further includes axial through-hole, it is set in the side of third annular step portion towards second axial end, oil scraper ring is set in axial through-hole, and adjacent third annular step portion towards second axial end side, in the surface of third annular step portion and oil scraper ring opposite, in the surface of third annular step portion towards oil scraper ring, and / or in the surface of oil scraper ring towards third annular step portion is set with micro groove to guide fluid flow. By the above structural design, the guide component provided by the utility model can discharge gas in inner chamber, so as to avoid the influence of oil gas mixture on the damping characteristic of shock absorber.

The application discloses a kind of bored pile super-pouring height double-pipe control devices, including the guide pipe of being lowered to the bored pile and pouring underwater concrete and the straight tube pipe of coaxially nesting in the guide pipe, the straight tube pipe upper end is provided with bayonet ring, the straight tube pipe lower end is formed into floating plate by turning outside, and symmetrically provided with placement slot on floating plate.The application also relates to bored pile super-pouring height double-pipe control method, improve the passive mode of construction personnel in prior art according to experience measurement concrete surface to analyze and judge, not influenced by experience and level of on-site construction personnel, with higher accuracy, and simple and easy to operate characteristics.

The utility model discloses an exhaust device and system. The exhaust device comprises a positive pressure side connector, a first isolating valve, a filtering monitor, a second isolating valve and a negative pressure side connector. The filtering monitor is used for filtering and monitoring air. Wherein the first end of the positive pressure side interface can be used for being connected with a positive pressure side pipeline of an external double-pipe differential pressure transmitter system, the second end of the positive pressure side interface is connected with the first end of the first isolating valve, and the second end of the first isolating valve is connected with the first end of the filtering monitor; the second end of the filtering monitor is connected with the first end of the second isolating valve, the second end of the second isolating valve is connected with the first end of the negative pressure side connector, and the second end of the negative pressure side connector can be used for being connected with a negative pressure side pipeline of an external double-pipe differential pressure transmitter system. The exhaust device is used for solving the exhaust problem of positive and negative pressure side pipelines in the operation state of a double-pipe differential pressure transmitter system, and the filter monitor can filter and monitor air to determine the bubble condition in the exhaust process.

The application discloses a defrosting control method, an air conditioning unit and a computer readable storage medium, and comprises the following steps: when the first temperature sensing bag and the second temperature sensing bag are both within T0±a, timing is started; when the first temperature sensing bag or both the first temperature sensing bag and the second temperature sensing bag deviate from the interval of T0±a, timing is stopped, and one of the first temperature sensing bag and the second temperature sensing bag is selected as a main temperature sensing bag according to a preset selection logic; the frost formation rate z is calculated by substituting the maintenance time length t into a preset frost formation rate calculation formula, the current preset defrosting interval is determined according to the frost formation rate and the current outdoor environment temperature parameter, and it is judged whether the defrosting mode is entered. The application detects the pipe temperature and the environment temperature through the double-pipe temperature sensing bag, calculates the frost formation rate through the maintenance time length, judges the current frost formation interval, carries out defrosting treatment according to different frost formation intervals, does not need to additionally increase a humidity detection device, is more accurate in judging the frost formation interval of the unit, and achieves precise defrosting.