34results about How to "Controllable heating" patented technology

The invention discloses a laser welding method for dissimilar metals, which is used for welding a high-melting-point metal workpiece and a low-melting-point metal workpiece. A gap is formed between the high-melting-point metal workpiece and the low-melting-point metal workpiece, and a laser beam irradiates from one side of the high-melting-point metal workpiece to one side of the low-melting-point metal workpiece to realize welding, so that low-melting-point metal vapor is easily volatilized, a combining part between the two workpieces is more uniformly and controllably heated, heat is more reasonably distributed, and the phenomena of splashing, perforating and the like can be avoided.

The present invention relates to an energy circulation air-conditioner. It includes the following several portions: energy converter and energy diffusion device connected with positive end of the described energy converter. It is characterized by that it also includes an energy storage device capable of making energy interchange with negative end of the described energy converter, the described energy storage device includes a box body for holding energy interchange agent, and on the circuit of the described energy converter a change-over switch is set, said change-over switch can make current direction be reversed. Besides, said invention also provides the working principle of said energy conversion air conditioner and its concrete operation method.

The invention discloses a preparation method of a titanium-niobium-zirconium-based hydroxyapatite biological composite material and belongs to the field of biomaterial preparation. The composite material of the invention employs titanium-niobium-zirconium alloy as a matrix, and hydroxyapatite as a bio-ceramic; and the weight of hydroxyapatite is 10-25% of that of the titanium alloy. The preparation process is as follows: filling a hydroxyapatite powder and a titanium alloy powder into a mill pot, sealing by alcohol, vacuumizing to 20-30Pa, milling for 6-8 h and drying in a vacuum oven; filling the dry powder into a graphite mold for cold forming; and finally carrying out spark plasma sintering with the sintering temperature at 1100 DEG C-1200 DEG C, first heating to 1000 DEG C by heating rate of in 100 DEG C / min, then heating to the sintering temperature by 25-50 DEG C / min and insulating for 6-10min with the pressure of 50-60MPa. The prepared biological composite material has elastic modulus of 25.4-45GPa, and has good mechanical properties and biocompatibility. The method of the invention is simple in process and low in production cost.

A double-CFB (circulating fluidized bed) reaction-regeneration system and method to prepare arenes with synthetic gas are provided. The system herein comprises an aromatization reactor and a catalystregeneration reactor which are connected with each other through a pipeline; the aromatization reactor comprises a first catalyst filling area and a second catalyst filling area; the catalyst regeneration reactor includes a fourth catalyst filling area and a third catalyst filling area; the aromatization reactor is filled with a hydrocarbon synthetic catalyst and an aromatization catalyst; under the action of a flow of gas, the hydrocarbon synthetic catalyst stays mainly in the area below, and the aromatization catalyst stays mainly in the area above. A regeneration method is also disclosed, including: after the aromatization catalyst is inactive, allowing the aromatization catalyst to enter a low-temperature hypoxic area of the catalyst regeneration reactor and then enter a high-temperature hyperoxic area of the catalyst regeneration reactor. The system and method herein have the advantages that controlling at different temperatures is achieved and catalyst design is less difficult.

The invention provides a method for inhibiting enzyme and killing bacteria. The method is characterized as follows: materials are put in a closed container and the container is vacuumized (vacuum drying is carried out by microwave); the vacuumizing is stopped and inert gas is pumped; the container is heated by microwave; the heating by microwave is stopped and vacuumizing is carried out to achieve rapid cooling. The invention makes the most of the characteristics of speediness, uniformity and easy-control of microwave heating, protection of the inert gas and vacuumizing to achieve rapid cooling, thus achieving good effect of inhibiting enzyme and killing bacteria.

The invention discloses a cancer treatment instrument, which is characterized by comprising a base, a protection cover, a microwave generator, a body temperature detector and a PLC (programmable logic controller) control unit, wherein the protection cover is arranged on the base; the microwave generator is arranged inside the protection cover; the body temperature detector and the microwave generator are both connected with the PLC control unit; a treatment table not connected with the base is arranged inside the base; the treatment table is used for a patient to stand on; the bottom of the base is connected with a servo motor through a gear set; the servo motor works to drive the base to positively and negatively rotate, so that the protection cover can rotate around the patient. The cancer treatment instrument has the advantages that the use is safe and convenient; the characteristics of short treatment time, little pain, low cost and the like are realized for certain cancers; the organ completeness can also be maintained; the curative effect is exact; the complications are few; and the application symptom range is relatively wide.

The invention relates to a rapid pre-warming starting system for a power plant steam turbine. The power plant steam turbine of the system at least comprises an operating adjacent machine and a nativemachine needing to be rapidly pre-warmed and started, the native machine comprises a high-pressure cylinder, first, the high-pressure cylinder is connected with a heater through a steam pipeline and asteam inlet control valve, second, the high-pressure cylinder is output to a native machine condenser through a main steam pipeline, a steam guiding pipe and a steam exhaust pipeline, and a steam guiding pipe steam-exhaust control valve, and third, the high-pressure cylinder is also connected to the native machine condenser after passing through the steam exhaust pipeline and a warming cylinder steam-exhaust control valve; and the heater further inputs coming steam of the adjacent machine after passing through the steam pipeline and a heating steam source coming-steam control valve, native machine auxiliary steam is input through the steam pipeline and a coming steam control valve, and the auxiliary steam is output to a next-stage heater of the adjacent machine through the steam pipeline,is output to a drain tank through the steam pipeline, and then output to the native machine condenser through the steam exhaust pipeline and a heater drain control valve. According to the rapid pre-warming starting system, the starting time of the cold starting process of the steam turbine can be effectively shortened, and the starting time length is lowered from 6.5-8 hours to be within 1 hour.

The invention belongs to the technical field of underground coal gasification, and particularly relates to an underground interlayer type coal in-situ gasification mining system and a construction method thereof. According to the gasification mining system and construction method thereof, a pre-control system is used for injecting a flame retardant to moisten coal, and the structure of a gasification system is controlled in advance; a heating vertical shaft is drilled into a coal seam lower base plate rock stratum, combustion equipment is arranged to heat the lower base plate rock stratum, coal is combusted to generate coal gas through the thermal conductivity of the lower base plate rock stratum, and then a gas collecting system collects the coal gas and conveys the coal gas to the ground; in the coal bed gasification process, the coal bed temperature and the lower base plate rock stratum stress are monitored; heating equipment is arranged in the coal seam lower base plate rock stratum, and disturbance to the coal seam is reduced; and the high-temperature-resistant coal wall is reserved by utilizing a pre-control system, so that the air tightness of a gasification cavity is improved, the coal seam is heated more uniformly and controllably, an ideal temperature field is provided for sufficient combustion of the coal seam, and the quality of produced coal gas is improved.

The invention discloses a titanium alloy / calcium pyrophosphate surface bio-composite material and a preparation method thereof, and belongs to the field of biomedical materials. The surface composite material uses as titanium alloy as the matrix, and calcium pyrophosphate and zirconium as a bio-ceramic layer. The process comprises the steps of: subjecting the titanium, niobium and zirconium powder to mechanical alloying for 6-8h and drying to obtain a titanium alloy mixed powder; milling and mixing the calcium pyrophosphate with the zirconium powder for 1-2h and drying to obtain a mixed calcium pyrophosphate powder; and respectively filling the titanium alloy mixed powder and calcium pyrophosphate mixed powder into an upper layer and a lower layer of a graphite mold by means of an auxiliary device, compacting, and sintering in a plasma sintering furnace to obtain the titanium alloy / calcium pyrophosphate surface bio-composite material. The surface composite material prepared by the invention has good interface combination, suitable strength and excellent surface biological activity, reaches composite layer thickness of 10mm, and can be used in human hard tissue replacement and repair. The manufacturing process is clean, simple in process, low in cost, and easy to achieve industrialization production.

The invention relates to a discharge device of a medicine frying pan used for Chinese herbal medicine processing, comprising a discharge hand wheel, a discharge worm, a discharge turbine and a shaft sleeve, wherein the shaft sleeve is fixedly connected with a support, the discharge worm is connected into the shaft sleeve by a bearing, the discharge hand wheel is arranged at one end of the discharge worm, the discharge worm is meshed with the discharge turbine, and the discharge turbine is arranged on a rotating shaft. The discharge worm is rotated by rotating the discharge hand wheel, so thatthe discharge turbine rotates; the discharge turbine is arranged on the rotating shaft and is connected with the rotating shaft by a bearing, so that the rotating shaft can be driven to rotate by therotation of the discharge turbine, so that a pan inclines laterally to pour fried Chinese herbal medicine out of the pan, thus realizing the aim of automatically discharging.

The invention relates to a medicine frying pan used for Chinese herbal medicine processing. The pan is of a hemispherical structure with an opening at the upper end and is a double-layer pan, an innerchamber is formed between an inner layer and an outer layer, rotating shafts are arranged at two sides of the pan, the rotating shafts are hollow rotating shafts, the hollow rotating shafts are communicated with the inner chamber of the pan and are connected with a support by bearings, the rotating shaft at one side of the pan is connected with an oil inlet pipe, the rotating shaft at the other side of the pan is connected with an oil return pipe, a discharge device is arranged on the support, the discharge device is connected with the rotating shaft at one side of the pan, a support plate isarranged on the pan, two ends of the support plate are in fastened connection with the opening at the upper end of the pan, a stirring device and an exhaust device are arranged on the support plate,a pan cover is arranged at each of two sides of the support plate, the pan covers are hinged with the support plate, and a heating device is arranged outside the pan. The Chinese herbal medicine in the pan is heated by utilizing heat conducting oil, and is stirred constantly in the frying process, so as to prevent the Chinese herbal medicine from being burnt; and the exhaust device is arranged onthe pan cover, and is used for pumping away smoke generated in the important drying process.

The invention discloses a low-temperature-resistant low-frequency heating device for transformers. The low-temperature-resistant low-frequency heating device for the transformers comprises a rectifying module, a filtering capacitor, an inversion module, a temperature measurement unit, a control element, a heating element and a cooling element, wherein the rectifying module, the filtering capacitor and the inversion module form a low-frequency heating device body, the heating element and the cooling element are connected with the control element, the output ends of the heating element and the cooling element are connected with the low-frequency heating device body, the temperature measurement unit is used for detecting temperatures of the rectifying module, the filtering capacitor and the inversion module and sending temperature information to the control element, the control element is used for displaying temperature values and sending control signals, and the heating element and the cooling element are used for heating or cooling the low-frequency heating device body according to the control signals. The low-temperature-resistant low-frequency heating device for the transformers can be used for start and operation of the transformers in high-cold and even gelid environments.

The invention discloses a defrosting method and device for evaporating a defrosted refrigerant through a special evaporator. The defrosting method comprises the following steps: the refrigerant in a main refrigeration pipeline is divided into the to-be-defrosted evaporator, and the divided refrigerant serves as a defrosting medium to release heat to melt frost on the evaporator; the defrosted refrigerant is conveyed into the evaporator special for conducting evaporative heat absorption on the defrosted evaporator to form an independent evaporative heat absorption route; and the evaporated refrigerant in the special evaporator is conveyed back to a compressor for circulation work. According to the defrosting method, by adopting the special evaporator to conduct uniform evaporative refrigeration on the defrosted refrigerant, the evaporation area of a refrigeration system is increased, thus the evaporation temperature of the refrigeration system during defrosting is not lower than the evaporation temperature during no frosting, and the refrigerating capacity of the system is improved; and adjustability is high during exhausting of the compressor for defrosting, the degree of superheatis easy to control, meanwhile the refrigerant can stably and continuously work, and the stability of the system is high.

The invention discloses a simple-opening traditional Chinese medicine electromagnetic rotation herbal medicine roaster, which comprises a rack, a motor, a spindle, a shell, a material inlet and outlet, a stirring barrel, an electromagnetic heating device, a smoke removal device and a control panel, wherein the shell is arranged on the rack; the front end of the shell is open; two ends of the rackare respectively provided with a lateral connecting rod; the motor is arranged in the rack; the spindle is fixedly installed in the stirring barrel; the lateral connecting rods are connected with twoends of the rack, the spindle is connected with the bracket through welding; the bracket is connected with the inner wall of the stirring barrel; the front end of the stirring barrel is open; a material shifting plate is arranged in the stirring barrel; the electromagnetic heating device is arranged on the outer side of the stirring barrel; the control panel is arranged on the shell; a power supply is connected through an electric wire; the smoke removal device is arranged on the upper part of the shell. The simple-opening traditional Chinese medicine electromagnetic rotation herbal medicine roaster is characterized in that an electromagnetic heating barrel is arranged on the outer side of the stirring barrel, so that heating is quick, heat is controllable, medicines are evenly heated, working efficiency is improved, and working environment is purified by the smoke removal device.

The invention relates to an environment-friendly indirect type roller heating device with heat preservation. The environment-friendly indirect type roller heating device with heat preservation comprises a heat preservation cover (2) and a roller (1) arranged in the heat preservation cover (2), wherein supporting wheels (9) which support and rotate the rotation of the roller (1) are arranged on theouter wall of the roller (1); a wire heater (5) is arranged on the outer wall of the roller (1), and the wire heater (5) is distributed on the roller (1) in a multi-point mode; and material guide blades (10) for stirring materials are arranged in the roller (1). A double-layer cylinder structure is adopted in the heating roller, an outer cylinder (provided with a barrel cover) is used for heat preservation, and an inner cylinder is used for heating. An external type is adopted in heating, heating units are arranged in a multi-point mode, a cylinder body is uniformly heated, and an asphalt mixture is heated through conduction and radiation, so that the temperature of the regenerated asphalt mixture is uniform, the gradation and the asphalt-aggregate ratio do not change obviously, and the quality of the asphalt mixture is ensured to a greater extent.

The invention belongs to the technical field of tobaccos, and particularly relates to a heating electronic cigarette. Micropores are formed in an inner coating layer, winding wire resistors are arranged in the micropores, and the sizes of the inner coating layer and the winding wire resistors are both small. The heating electronic cigarette can be heated up rapidly under the combined effect of theinner coating layer and a permeable magnetic material when working, thereby having the advantages of being small in size and rapid in heating.

The invention relates to an automatic rotating temperature control frying pan, and belongs to the technical field of food processing equipment. The automatic rotating temperature control frying pan comprises a shell and a pan body, a rotating driving mechanism, a combustion mechanism, a supporting mechanism and a temperature control assembly are arranged in the shell, the supporting mechanism comprises a supporting sleeve and a rotating shaft rotationally assembled in the supporting sleeve through a fixed bearing, and the rotating shaft is in transmission connection with the rotating driving mechanism; the temperature control assembly comprises a temperature display meter, an ignition controller, a temperature probe and a conductive slip ring; the temperature display meter is used for displaying the real-time temperature of the surface of the pot body. The temperature probe makes contact with the surface of the pot body to detect the real-time temperature of the surface of the pot body; and the ignition controller controls the combustion mechanism to be started when the rotary driving mechanism acts, and controls the combustion mechanism to be closed when a numerical value displayed by the temperature display meter reaches a set temperature. Uniform heating of the pot body and control of the surface temperature of the pot body are well combined through the rotary driving mechanism and the temperature control assembly, so that the surface temperature of the pot body is controllable, and the taste of food is guaranteed.

The invention provides a roller-type tobacco feeding machine with a composite-type heating system. The roller-type tobacco feeding machine comprises a machine frame, a material conveying roller slantwise installed on the machine frame, a transmission device and a hot air circulating system installed on the material conveying roller. The higher side of the material conveying roller is provided witha feeding chamber, and the lower side is provided with a discharging port. A roller wall of the material conveying roller is of a double-layer structure, and a steam heat-radiating tube is arranged in an interlayer. An inlet and an outlet of the steam heat-radiating tube are arranged outside the roller wall. The discharging port of the material conveying roller is provided with a moisture removing chamber. The discharging port is placed at the lower end of the moisture removing chamber, and the upper part of the moisture removing chamber is connected with a moisture removing pipe and a moisture removing fan. The roller-type tobacco feeding machine does not affect material moisture in a heating process, and a material is more uniformly heated, and controlled. A material adhesion quantity of the roller wall is effectively reduced, and labor intensity of an operator is reduced in a maintaining process.

The invention discloses a method for detoxification of citrus by utilizing microwaves, and belongs to the technical field of microwave application. The method is characterized in that during microwave pretreatment, the microwave irradiation frequency is 1.0 GHz-3.0 GHz, the power is 100-900 W, the microwave irradiation time is 5-20 seconds, then pausing is carried out for 10-30 seconds, repetitive operation is carried out 3-10 times, the temperature of each part of the citrus is increased to 40-45 DEG C, and the constant temperature is maintained for 30-60 seconds; then it is adjusted that the microwave irradiation frequency is 350 MHz-950 MHz, the power is 1,000-3,000 W, the microwave irradiation time is 3-10 seconds, then pausing is carried out for 20-60 seconds, repetitive operation is carried out 5-20 times, the temperature of each part of the citrus is increased to 50-55 DEG C, the constant temperature is maintained for 1-5 minutes, and citrus detoxification is carried out by utilizing the microwaves. The method for detoxification of the citrus by utilizing the microwaves can make each part of the citrus reach the fatal temperature of candidatus liberibacter more quickly and evenly, and a tree body is not affected; under the non-thermal effect of a microwave electromagnetic field, nucleic acid, protein and other molecules in the candidatus liberibacter are easy to denature and inactivate to achieve double sterilization effects; the detoxificated citrus through the microwaves are detected by adopting GB / T 28062-2011 <Real-Time Fluorescence PCR Detection Method of Candidatus Liberibacter>, and the negative conversion ratio of the candidatus liberibacter is greater than or equal to 82%. The method is an efficient, quick and environment-friendly citrus detoxification method.

A two-stage circulating fluidized bed reaction-regeneration system and method for preparing aromatics from synthesis gas, comprising an aromatization reactor and a catalyst regeneration reactor, the two are connected to each other through pipelines, and the aromatization reactor includes a first The catalyst loading area and the second catalyst loading area; the catalyst regeneration reactor includes the fourth catalyst loading area and the third catalyst loading area, and the hydrocarbon synthesis catalyst and the aromatization catalyst are filled in the aromatization reactor, and under the action of air flow, The hydrocarbon synthesis catalyst mainly stays in the lower area, and the aromatization catalyst mainly stays in the upper area, and it is announced that after the aromatization catalyst is deactivated, it first enters the low-temperature low-oxygen zone of the catalyst regeneration reactor, and then enters its high-temperature high-oxygen zone. The regeneration method of the zone, the invention realizes the control of different temperatures, and reduces the design difficulty of the catalyst.

The invention relates to the technical field of electric devices, in particular to magnetic heating equipment, which comprises a rotary table, a motor, a metal heating body and a heat conduction bar, wherein a plurality of magnets are symmetrically and circularly distributed on the rotary table in a way that south poles and north poles of the magnets are alternately arranged; a rotating shaft is arranged below the centre of the rotary table and is driven by the motor; and the metal heating body is positioned above the rotary table and is connected with the heat conduction bar through a hot conducting wire. The magnetic heating equipment has the advantages of simple structure, convenience in installation, low energy consumption, controllable heating rate, stable heat supply, wide application range and the like.

The invention discloses a three-microwave multi-wheel cooperation type coiled material paving vehicle which comprises a trolley body, a rolling device assembly, an oil coating device assembly, a microwave heating device and a power supply assembly are installed on the trolley body, the trolley body comprises a trolley frame, universal wheels are installed at the four corners of the bottom face of the trolley frame, and a trolley handle is installed at the rear end of the trolley frame. A gear shifting adjusting rod and a frequency conversion control wheel are installed on the portion, below the handlebar, of the trolley frame, a placement frame is fixed to the middle of the top face of the trolley frame, a waterproof roll is installed on the inner side of the lower portion of the placement frame, the top side of the placement frame is rotationally connected with a guide roller, and a rolling roller is installed on the lower side of the waterproof roll. When waterproof coiled material paving is carried out, working can be started only by turning on a power source to push the trolley, no technical requirement for constructors exists, compared with traditional flaming heating, microwave heating is safer and more environmentally friendly, temperature rising is controllable, heating is uniform, and the coiled material paving quality is greatly improved.

The invention relates to a diesel heating device for a vehicle. The diesel heating device for the vehicle is used for heating diesel by utilizing heat of tail gas of the vehicle, and is formed by connecting a tail gas heat collecting and exchanging box with a tail gas flow control box, wherein the tail gas heat collecting and exchanging box is provided with a plurality of concentric radial heat pipes; and the tail gas flow control box is provided with two guide flow control plates which are symmetrically arranged, have a flow guiding effect and effects of a valve, and can relatively rotate synchronously within a range of 60 degrees. An exhaust channel port of the diesel heating device can be directly connected with an exhaust channel of an engine of the vehicle, can circularly rotate around the center of the exhaust channel of the engine to be arranged in optional directions, and is connected to a fuel supply system of the engine through a fuel tube joint, when the engine works, fuel can be heated by the heat of tail gas discharged from the engine, and diesel is sufficiently isolated from the tail gas of the exhaust channel in the structure. The flowing direction and the flow of the tail gas are regulated and controlled in a stepless manner by operating an adjusting plate driving mechanism, and during running of the diesel heating device, the temperature of the fuel, input of the device or running stop are controlled. The safety of the diesel heating device is improved, and heating temperature and heating time are controllable. The diesel heating device for the vehicle can be a normal facility of the vehicle, and is not required to be detached in summers, and by the diesel heating device, the vehicle can continue using low-grade diesel in winters.

The invention discloses a method for preparing a titanium-niobium-zirconium-based hydroxyapatite biocomposite material, which belongs to the field of biomaterial preparation. The composite material prepared by the invention adopts the titanium-niobium-zirconium alloy as a matrix, and the hydroxyapatite is bioceramics; the mass of the hydroxyapatite is 10-25% of that of the titanium alloy. Its preparation process is as follows: put hydroxyapatite and titanium alloy powder into a ball mill jar, seal it with alcohol and evacuate to 20-30Pa, and dry it in a vacuum drying oven after ball milling for 6-8 hours; put the dried powder into Graphite molds are formed by cold pressing, and finally spark plasma sintering is used. During the sintering process, the sintering temperature is controlled at 1100°C~1200°C, and the temperature is first heated to 1000°C at a heating rate of 100°C / min, and then heated to 25~50°C / min. The sintering temperature is kept warm, the holding time is 6-10min, and the pressure is 50-60MPa; the biocomposite material prepared by the present invention has an elastic modulus of 25.4-45GPa, and has both excellent mechanical properties and biocompatibility; the method of the present invention is simple in process , Low preparation cost.

The invention discloses a concentric thin-walled steel pipe welding machine, which comprises a vertically arranged welding column with a cylindrical outer wall, used to cover two welded steel pipes, and a plurality of horizontally arranged welding columns centered on the central axis of the welding column The welding heads are distributed in a circular array to realize simultaneous gathering and dispersing; the welding heads and the welding columns are respectively connected to the positive and negative poles of the power supply. When all the welding heads are gathered around the central axis of the welding column at the same time until the front end of the welding head is in contact with the welded steel pipe located on the periphery, the welding head is connected to the welding column through the welded steel pipe, the circuit is closed, and the resistance heat at the welding point is used to realize Electric welding of the welded steel pipe; the above-mentioned concentric thin-walled steel pipe welding machine can adjust the heat generated at the welding place by controlling the size of the welding current and the length of time the welding head contacts the welded steel pipe, so as to avoid the welded steel pipe being worn out due to excessive heat at the welding place through.

The invention relates to the technical field of coolers, and particularly discloses a control method of a semiconductor refrigeration cooler. The control method comprises the following steps that the current working mode of a refrigeration assembly is confirmed; in the current working mode, a temperature adjusting instruction of a user is received; the initial rotating speed of a fan assembly and the initial power of the refrigeration assembly are determined according to the temperature adjusting instruction; temperature data of the first temperature sensor, the second temperature sensor and the third temperature sensor is acquired in real time; according to the temperature data, the actual rotating speed of the fan assembly matched with the temperature adjusting instruction and the actual power of the refrigeration assembly are calculated; and operation of the fan assembly is controlled according to the actual rotating speed of the fan assembly, and work of the refrigeration assembly is controlled according to the actual power of the refrigeration assembly. The invention further discloses a control device of the semiconductor refrigeration cooler, an electric control system and the semiconductor refrigeration cooler. According to the control method of the semiconductor refrigeration cooler, the refrigeration function and the heating function can be achieved through control.

The invention discloses a concentric thin-wall steel pipe welding machine. The concentric thin-wall steel pipe welding machine comprises a welding column and a plurality of welding heads, wherein thewelding column is vertical arranged, provided with a cylindrical outer wall, and is used for sleeving two welded steel pipes, and the welding columns are horizontally arranged, and are distributed inan annular array by taking a center axis of the welding column as the center so as to realize simultaneous gathering and dispersion; and the welding head and the welding columns are connected to a positive electrode and a negative electrode of a power supply respectively. When all the welding heads are gathered by taking the center axis of the welding column as the center until the front ends of the welding heads are in contact with the welded steel pipes located on the periphery, the welding heads are connected with the welding column through the welded steel pipes, a circuit is closed, and electric welding of the welded steel pipes is realized by utilizing the resistance heat at the welding position; and the heat generated at the welding position can be adjusted by controlling the welding current and the duration of the welding head being in contact with the welded steel pipes by the concentric thin-wall steel pipe welding machine, and the welded steel pipes are prevented from beingpenetrated by excessive heat of the welding position of the welded steel pipes.