689 results about "Vapor phase" patented technology

Systems and methods for providing lubrication to a gas turbine engine are described. An example gas turbine engine includes a plurality of bearings disposed along an axial length of a rotatable shaft to provide rotational support between a static structure and at least one of a compressor and a turbine of the gas turbine engine. The gas turbine engine further includes a fuel system operable to deliver a mixture of fuel and lubricant sequentially to at least one of the plurality of bearings and the combustor so that during operation of the gas turbine engine, at least the lubricant within the mixture is in a liquid phase prior to being received by the at least one of the plurality of bearings, and in a vapor phase once the lubricant is delivered to the at least one of the plurality of bearings.

Vapor deposition processes for forming thin films comprising molybdenum on a substrate are provide. In some embodiments the processes comprise a plurality of deposition cycles in which the substrate is separately contacted with a vapor phase molybdenum precursor comprising a molybdenum halide, a first reactant comprising CO, and a second reactant comprising H2. In some embodiments the thin film comprises MoC, Mo2C, or MoOC. In some embodiments the substrate is additionally contacted with a nitrogen reactant and a thin film comprising molybdenum, carbon and nitrogen is deposited, such as MoCN or MoOCN.

The invention discloses a high-strength PET composite material and a preparation method thereof, and relates to the technical field of polymer materials. The invention first adds fumed silica during the preparation of graphene aerogel, and the siloxy groups on the surface of the fumed silica combine with the hydroxyl groups of the graphene oxide hydrogel, and the aerogel is mixed after heat treatment, which can improve the strength of the composite material and achieve excellent hydrophobic effect; secondly, dopamine is grafted on the surface of the aerogel, and the amino groups of the dopamine and the silanol groups of the silica undergo dehydration condensation to form a composite swelling layered silicate to prepare a hybrid filler; dopamine improves the dispersibility and compatibility of the filler in PET; when fine cracks appear in the composite material due to aging, the swelling layered silicate and the dopamine rainwater work together to achieve a self-repairing effect, and can also remove free radicals, so that the strength of the composite material is stable and the anti-aging performance is improved. The PET composite material prepared by the invention has high strength and anti-aging effects.

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a preparation method of a graded ordered silicon-carbon negative electrode material for a lithium ion battery, which comprises the following steps: (S1) mixing phenolic resin and a template agent, calcining, and etching to obtain porous carbon containing macropores; (S2) carrying out cracking and carbon coating on the silicon source gas to obtain nano crystalline silicon containing a carbon coating layer; (S3) mixing the porous carbon with the nano crystalline silicon containing the carbon coating layer, and then carrying out ultrasonic vibration, so that macropores of the porous carbon are filled with the nano crystalline silicon to obtain a silicon-carbon composite material I; (S4) treating the silicon-carbon composite material I by using a carbon-containing sealing agent, and then activating to obtain a silicon-carbon composite material II; and (S5) carrying out vapor phase silicon deposition on the silicon-carbon composite material II to fill the amorphous silicon in the pores of the porous carbon, and then carrying out carbon coating to obtain the graded ordered silicon-carbon negative electrode material. The silicon-carbon negative electrode material prepared by the invention is of a composite structure in which crystalline silicon and amorphous silicon are spatially and orderly distributed, so that the structural stability and the uniform distribution of silicon are realized.

The present application provides an anti-clogging type precipitation tower plate, comprising a tower plate, the tower plate comprising a liquid receiving area, a liquid downfalling area, and a vapor phase channel, the liquid downfalling area is provided with an overflow weir near the vapor phase channel side, a liquid downfalling hole is provided in the liquid downfalling area, and a baffle is provided at the lower part of the liquid downfalling hole; in the present application, the liquid phase passes through the baffle and the vapor phase channel in the tower, undergoes multiple baffles and falling processes, so that the mass transfer and heat transfer effects are enhanced, and at the same time, the flushing effect of the liquid phase also helps to prevent solid accumulation and clogging on the tower plate, improves the mass transfer efficiency and operation effect, and can realize the discharge of solid products from the tower plate to the tower kettle and finally out of the system; and the tower plate of the present application is provided with independent vapor phase and liquid phase channels, and effective vapor-liquid mass transfer is realized between the tower plates, thereby fully avoiding the problem of vapor phase channel clogging, and because the liquid flow moves in a zigzag line in the tower, the residence time of the liquid phase in the tower is extended, so that the raw materials have a longer decomposition or polymerization time.

The invention discloses a preparation method of a high-purity ultra-clean hydroxylamine aqueous solution. A four-stage purification process comprises the following steps: 1) low-temperature chelation-ceramic membrane metal removal; 2) molecular sieve membrane rectification decomposition prevention; 3) pulse electrodialysis reversal deep desalination; and 4) gradient filtration terminal refining. According to the preparation method of the high-purity ultra-clean hydroxylamine aqueous solution, a low-temperature molecular sieve membrane rectification technology is adopted, hydroxylamine liquid-phase thermal decomposition is avoided through a vapor phase separation mechanism, and the decomposition rate is reduced to 1t from 15% of a traditional process; the method comprises the following steps of: removing metal through chelation-electrodialysis synergistically, ensuring that Fe and Cu ion residues are less than or equal to 0.05 ppb through a thiosemicarbazide-bipolar membrane system, ensuring the nitrogen environment in the whole process, ensuring that the dissolved oxygen is less than or equal to 5ppb, replacing liquid phase distillation with molecular sieve membrane vapor phase separation, solving hydroxylamine liquid phase thermal decomposition, and breaking through the trace metal removal limit by combining thiosemicarbazide-bipolar membrane synergistically removing impurities. And then through nanoscale terminal filtration, the metal / particle control reaches ppb-level limit which is superior to the SEMI standard, and double spanning of quality and cost is realized.

A process for forming a vapor-deposited ZIF-8 metal organic framework includes: conducting a gas surface reaction between an ALD-deposited ZnO and 2-methylimidazole to form a vapor-deposited ZIF-8 metal organic framework, wherein the gas surface reaction is conducted at a temperature greater than 140 C, and wherein the gas surface reaction is conducted at a pressure of less than 1000 mTorr. In a particular embodiment, the gas surface reaction is conducted at a temperature of 160 C. A process for preparing a laminate includes: performing ALD of zinc oxide as a base between 1 nm to 10 nm in thickness, exposing 2-methylimidazole vapor phase linker at chemical vapor deposition at a temperature range of greater than 140 C to less than or equal to 180 C in a vacuum condition, and cycling of the ZnO ALD and 2-methylimidazole exposure to deposit a film or fill a gap.

The invention provides modified gas-phase nano SiO2, a composite emulsion, a super-hydrophobic self-cleaning coating and a preparation method thereof, and belongs to the field of material protection. The surfaces of nano particles of the modified gas-phase nano SiO2 are provided with long-chain hydrocarbons and contain unsaturated double bonds; wherein the number of carbon atoms of the long chain hydrocarbon is 5-50. According to the invention, the hydrophilic gas-phase nano SiO2 is modified, so that the surface roughness is improved, and the wear resistance and corrosion resistance of the coating are improved.

The invention provides a two-phase flow boiling heat transfer numerical simulation method, device and equipment based on deep learning and a storage medium, and relates to the technical field of heat transfer science, the method comprises the following steps: inputting a target input parameter into a target deep neural network model to obtain a bubble separation characteristic key parameter, and constructing a wall surface heat flow distribution model according to the key parameter; the bubble separation characteristic key parameters comprise bubble separation diameter, separation frequency, slippage speed, slippage distance, rising diameter and nucleation density; embedding the bubble wall surface heat flow distribution model into the Euler-Euler two-fluid framework to obtain the embedded two-fluid framework; the embedded two-fluid framework comprises a mass conservation equation, a momentum conservation equation and an energy conservation equation of a liquid phase and a vapor phase; simulation of a two-phase flow boiling heat transfer numerical value is carried out through the two embedded fluid frames, and liquid-phase and vapor-phase temperature field and velocity field distribution is obtained. According to the method, the applicability of numerical simulation on the macroscopic boiling phenomenon is high.

The invention discloses a thermal power generating unit main reheating steam temperature wide-load self-adaptive adjusting method and system, relates to the technical field of electric power industry automation and control, and aims at solving the problems that an existing adjusting method is large in steam temperature fluctuation, high in thermal stress and poor in main reheating collaboration under the wide-load working condition. The method comprises the steps of calculating main steam phase saturation and mapping a target value; calculating the maximum change rate based on the thermal physical parameters of the material, and generating a reference track with the limited change rate; the steam phase saturation of the main steam is used as a phase reference, and the reheated steam is controlled to respond according to a preset phase difference; a combustion system, a flue gas temperature adjusting baffle and a temperature reducing water system are cooperatively controlled; the system comprises a vapor phase saturation processing module, a dynamic boundary generation module, a phase coordination control module, an execution mechanism coordination module, a steady state detection module and a mode switching module. Accurate steam temperature adjustment under the wide load is achieved, material thermal stress is reduced, unit operation safety and economical efficiency are improved, and the variable-load operation requirement of the unit is met.

A thermomodulating heat pipe is provided including a heat pipe envelope having a capillary wick extending substantially continuously the full length of the heat pipe and a void space interior of the capillary wick. The heat pipe envelope has a nominal evaporator section, a nominal condenser section where the nominal condenser section includes an active condenser portion and an inactive condenser portion, and a reservoir section extending from the inactive condenser portion. At a nominal condition, a heat pipe fluid is provided with a liquid phase filling the capillary wick and a vapor phase filling the void space of the nominal evaporator section and the active condenser portion, a non-condensable gas filling the void space of at least the reservoir section and the inactive condenser portion. Depending on thermal conditions, both prograde and retrograde heat transfer are enabled.

The utility model provides a base carrier and vapor phase growth equipment, the bottom surface of a top plate of the base carrier intersects with the inner wall of a cylindrical side plate to form a first connecting surface, the top of the first connecting surface is higher than the bottom surface of the top plate, the top surface of the top plate intersects with the outer wall of the cylindrical side plate to form a second connecting surface, and the first connecting surface sinks towards the second connecting surface. The average thickness between the first connecting face and the second connecting face is not larger than the average thickness of the top plate, and therefore the peripheral area formed by intersection of the top plate and the cylindrical side plate is thinned. The heating device of the vapor phase growth equipment is arranged below the top plate carried by the base, namely, in the thinned peripheral area, so that more heat can be provided for the peripheral area of the top plate through the edge heating area compared with that of the internal area, heat can be gathered in the middle area, and further more uniform reaction temperature can be provided for the base and the substrate; and the temperature control precision of vapor phase growth equipment and the film growth quality of products are improved.

The invention provides a method for growing an aluminum nitride thick film through a hydride vapor phase epitaxy method, and belongs to the technical field of third-generation semiconductor material preparation. According to the method, an aluminum source area in HVPE equipment is improved, supply of a multi-partition independent control aluminum source is provided, a periodic etching control strategy of an HCl gas channel is introduced, and a nested collaborative epitaxy method of outer-layer aluminum source rotation and inner-layer growth cycle embedded etching is formed. The problems of aluminum source degradation, nozzle blockage and stress accumulation in existing HVPE growth can be effectively solved, and long-time continuous operation of epitaxial AlN of the HVPE equipment is achieved; interruption and replacement operations caused by degradation of the aluminum source in long-time growth are avoided; nozzle area deposition is effectively removed, and the flow field stability is maintained; the stress is dynamically released, the crack occurrence rate is reduced, the film layer integrity is improved, and the method is suitable for HVPE equipment transformation and upgrading.

The utility model relates to the technical field of aluminizing, and provides a gas phase aluminizing tool for an engine turbine blade, which comprises a loading box, and the loading box comprises a chassis for loading aluminizing raw materials; the bottom net is placed at the top of the chassis; the outer box is used for loading aluminizing raw materials and is of an annular structure with the upper end and the lower end opened, meshes are formed in the inner side of the outer box, and the outer box is placed on the outer edge of the bottom net; the inner box is of an annular structure with the upper end and the lower end opened, meshes are formed in the inner side and the outer side of the inner box, the inner box is placed in the center of the bottom net, and a placing area used for placing blades is formed between the inner box and the outer box. The base plate, the outer box and the inner box are all used for containing aluminizing raw materials, the blade is placed in the containing area between the outer box and the inner box, so that the aluminizing raw materials are arranged on the lower portion and the side face of the blade, the follow-up aluminum atmosphere can make contact with all the surfaces of the blade conveniently, and the aluminizing thickness and quality consistency of all the surfaces of the blade are improved.

A fluid coker reactor may be heated with minimal combustion of coke. As an example, a method of heating coke in a fluid coker may include: providing a fluid coker reactor; reacting heavy oil feedstock in a coking zone of the fluid coker reactor to form a vapor phase and hot coke; stripping at least a portion of hydrocarbons that adhere to the hot coke in a stripping zone located in a lower portion of the fluid coker reactor; scrubbing the vapor phase from the fluid coker reactor in a scrubber; and heating the hot coke in a heater, wherein the heater receives the hot coke from the fluid coker reactor, wherein the heater heats the hot coke without substantially combusting the hot coke, and wherein the heater produces a coke product.

A process for producing a porous host structure or a powder mass of multiple porous particulates containing silicon oxide (SiOx) therein, comprising (a) providing a porous host structure having a volume fraction of pores from 5% to 99.9%, wherein the porous host structure is selected from a carbonaceous, graphitic, graphene, or metallic material; (b) catalytically vaporizing Si from a mixture of a catalyst and elemental Si or a Si-containing material to form a vapor phase of Si or a precursor to Si; (c) immediately directing the vapor phase into pores of the porous host structure and facilitating the vapor phase to form solid Si particles or coating deposited in the pores to form a Si-impregnated porous host structure; (d) exposing the Si to an oxidizing environment to obtain SiO2-coated Si particles / coating or SiOx; and (e) optionally breaking and reducing the SiOx-impregnated porous host structure into smaller porous particulates.

A mechanical pump-free flow boiling heat sink, including an evaporator, a two-phase flow steam injector, a first condenser, a boiling pool and a second condenser. A vapor outlet of the evaporator is communicated with a vapor-phase inlet of the two-phase flow steam injector. A liquid-phase outlet of the evaporator is communicated with an inlet of the boiling pool. An outlet of the boiling pool is communicated with an inlet of the second condenser. An outlet of the second condenser is communicated with a liquid-phase inlet of the two-phase flow steam injector. An outlet of the two-phase flow steam injector is communicated with an inlet of the first condenser. An outlet of the first condenser is communicated with an inlet of the evaporator.

The invention provides a method for growing a (310) oriented beta-Ga2O3 single crystal thick film on a sapphire substrate. The method comprises the following steps: cleaning the sapphire substrate and then carrying out annealing treatment; and with hydrogen chloride gas, gallium metal and oxygen as reaction sources, epitaxially growing a (310) oriented beta-Ga2O3 single crystal thick film on the treated sapphire substrate by using a hydride vapor phase epitaxy method. According to the method for growing the (310) oriented beta-Ga2O3 single crystal thick film on the sapphire substrate, the process is simple, operation is easy, controllability is high, the obtained (310) oriented beta-Ga2O3 single crystal thick film is smooth in surface, compact and uniform in thickness, the crystallinity of the single crystal film layer is high, and the growth requirement of a single crystal epitaxial film layer of tens of micrometers can be met; in addition, the method provided by the invention can realize large-batch and large-scale production of the (310) oriented beta-Ga2O3 single crystal thick film, and meets the device preparation requirements.

A slurry reactor system including a slurry reactor configured to convert, under slurry hydroconversion conditions, a slurry reactor content flowing upwards and containing a feedstock including one or more of fats, oils and greases, a slurry hydroconversion catalyst and a hydrogen stream to a slurry hydroconversion effluent containing a slurry phase effluent including catalyst particles and a liquid product and a vapor phase effluent including a hydroconversion product, and one or more separation units in fluid communication with the slurry reactor to receive the slurry hydroconversion effluent. A given one of the one or more separation units is configured to separate the slurry phase effluent from the vapor phase effluent.

The invention relates to a composite copper foil and a preparation method and application thereof, and the preparation method of the composite copper foil comprises the following steps: (1) depositing a copper layer on a polymer substrate by magnetron sputtering, and then coating a self-assembly molecular transition layer on the polymer substrate deposited with the copper layer through liquid-phase soaking treatment or vapor deposition treatment, a composite structure layer is obtained; and (2) sequentially carrying out water electroplating treatment and post-treatment on the composite structure layer obtained in the step (1) to obtain the composite copper foil. The surface of the magnetron sputtering metal layer is modified with chemical molecules with high binding force with metal copper to serve as a transition layer, the binding force of the magnetron sputtering metal layer and a hydroelectric plating layer is enhanced, and the mechanical property and the electrical property of the composite copper foil are improved in combination with optimization of a hydroelectric plating process and a formula.

A slurry reactor system including a slurry reactor configured to convert, under slurry hydroconversion conditions, a slurry reactor content flowing upwards and containing a feedstock including one or more of fats, oils and greases, a slurry hydroconversion catalyst and a hydrogen stream to a slurry hydroconversion effluent containing a slurry phase effluent including catalyst particles and a liquid product and a vapor phase effluent including a hydroconversion product, and a separation unit internal to the slurry reactor, the separation unit being configured to separate at least a portion of the vapor phase effluent from the slurry hydroconversion effluent to produce a mixture of vapor and the slurry hydroconversion effluent having a reduced vapor phase content. The separation unit is configured to use a pump to recirculate the mixture of vapor and the slurry hydroconversion effluent flowing downwards in the slurry reactor to be combined with the slurry reactor content.

The invention provides a liquid-gas phase change ejection inner trajectory modeling method, a liquid-gas phase change ejection simulation method and electronic equipment. A liquid-gas phase change ejection system comprises at least one phase change power unit. The liquid-gas phase change ejection inner trajectory modeling method comprises the step of dividing a liquid-gas phase change ejection inner trajectory into a phase change power unit flow model, a primary chamber energy model and a projectile body motion parameter model. According to the method, the liquid-gas phase change ejection inner ballistic model comprising the multiple phase change power units is constructed, the acting time of the phase change device is prolonged, the preset speed can be achieved when the ejection overload control requirement is high and the overload does not exceed the limit value, and the inner ballistic parameter change process in the carbon dioxide phase change ejection expansion acting process can be accurately calculated.

A slurry reactor system including a slurry reactor configured to convert, under slurry hydroconversion conditions, a slurry reactor content flowing upwards and containing a feedstock including one or more of fats, oils and greases, a slurry hydroconversion catalyst and a hydrogen stream to a slurry hydroconversion effluent containing a slurry phase effluent including catalyst particles and a liquid product and a vapor phase effluent including a hydroconversion product, and a separation unit external to the slurry reactor to separate the slurry phase effluent from the vapor phase effluent to produce a recycled slurry stream. An inlet of the separation unit is in fluid communication with an outlet of the slurry reactor to receive the slurry hydroconversion effluent from the slurry reactor and an outlet of the separation unit is in fluid communication with an inlet of the slurry reactor to receive the recycled slurry stream from the separation unit.

The current disclosure relates to methods for forming a film comprising transition metal on a substrate. The disclosure further relates to a transition metal layer, to a structure and a device comprising a layer that comprises a transition metal. In the method, transition metal is deposited on a substrate by a cyclic deposition process. The method comprises providing a substrate in a reactor chamber and executing a cyclical deposition process. The cyclical deposition process comprises the steps of providing a transition metal precursor in vapor phase into the reaction chamber and providing a halogen precursor in vapor phase into the reaction chamber to form a film comprising elemental transition metal on a substrate. The halogen precursor comprises only one halogen atom. The disclosure further relates to a deposition assembly for depositing a material comprising transition metal on a substrate.

A circulating vapor phase soldering device, which comprises: a liquid storage tank (10), the liquid storage tank (10) being used for storing a vapor phase liquid; a preheating apparatus (20), the preheating apparatus (20) being connected to the liquid storage tank (10) and heating the vapor phase liquid to a first temperature; a heating cavity (30), the heating cavity (30) being connected to the preheating apparatus (20) and being used for heating the vapor phase liquid until same evaporates, so as to heat a workpiece; a recovery apparatus (40), the recovery apparatus (40) being connected to the heating cavity (30) and the liquid storage tank (10), and being used for recovering the vapor phase liquid from the heating cavity (30) into the liquid storage tank (10); and a piping system (50), the piping system (50) being used for driving the vapor phase liquid to sequentially enter, from the liquid storage tank (10), the preheating apparatus (20), the heating cavity (30) and the recovery apparatus (40), and for driving the vapor phase liquid to enter the liquid storage tank (10) from the recovery apparatus (40). The liquid storage tank (10), the preheating apparatus (20), the heating cavity (30) and the recovery apparatus (40) are connected into a loop by means of the piping system, such that after soldering is completed, the vapor phase liquid can flow back into the liquid storage tank (10) for storage, thereby realizing full cyclic utilization of the vapor phase liquid during a soldering process, improving the utilization efficiency of the vapor phase liquid, reducing resource consumption, and lowering production and processing costs.

The utility model provides a substrate holding device and vapor phase growth equipment. The substrate holding device comprises a bearing base. The upper surface of the bearing base is provided with a groove for bearing a substrate, the top edge part of the bearing base is a peripheral protruding part, and an arc-shaped surface of which the curvature radius does not exceed 20mm is arranged between the side wall and the bottom surface of the peripheral protruding part; the bearing base is internally provided with an air channel, a first end opening of the air channel is located in the bottom face of the groove, a second end opening of the air channel is led out from the arc-shaped face, and due to the fact that the top edge of the bearing base is the peripheral protruding part, when air flows through a narrow area between the peripheral protruding part and the inner wall of the cavity, the flow speed is increased, and local pressure is increased; when the substrate is bent, a low-pressure area is generated near the arc-shaped surface, and then a remarkable negative pressure effect is generated in the air channel, so that the substrate is adsorbed on the bottom surface of the groove, the contact force between the substrate and the bottom surface of the groove is increased, and the substrate is prevented from warping and separating from the bottom surface of the groove.

The invention relates to the technical field of semiconductor material preparation, in particular to a gallium nitride single crystal wafer material preparation method which comprises the following steps: placing a silicon carbide substrate slice larger than a standard size in an accommodating groove of a graphite tray, and installing a cylindrical silicon nitride ceramic protective cover to assemble a substrate tray; putting the substrate tray into a magnetron sputtering growth chamber to prepare a zinc-aluminum-oxygen polycrystalline thin film and an aluminum nitride polycrystalline thin film in sequence; the substrate tray is placed in a high-temperature and high-vacuum annealing furnace chamber for high-temperature and high-vacuum annealing treatment, and the substrate tray is placed in a hydride vapor phase epitaxy reaction chamber for preparing the gallium nitride single crystal thick film material; cutting, grinding and polishing the peeled gallium nitride single crystal thick film wafer with the size larger than the standard size to obtain a gallium nitride single crystal wafer material with the standard size; and the stripped silicon carbide substrate slice and the used cylindrical silicon nitride ceramic protective cover can be repeatedly used after being cleaned. According to the method, low-stress, low-dislocation-density, low-cost and high-yield preparation of the standard-size gallium nitride single crystal wafer material can be realized.

The invention discloses a two-dimensional near-free-surface underwater explosion cavitation forecasting method, and relates to the technical field of explosion.The method comprises the steps that a mixed fluid is regarded as a mixture of multiple fluid media, and a multiphase compressible fluid motion control equation related to state parameters of the mixed fluid before the mixed fluid reaches an equilibrium state and the mass fraction of the fluid media of all phases is constructed; then constructing a thermodynamic state equation of any k-phase fluid medium based on an NASG equation, and constructing a cavitation phase change equation after the mixed fluid completes phase change relaxation to reach an equilibrium state by considering the phase change process of a liquid phase and a steam phase when a flow field changes; and solving an equation set formed by a multiphase compressible fluid motion control equation, a thermodynamic state equation of each phase of fluid medium and a cavitation phase change equation in each cycle step to obtain a numerical forecasting result. According to the method, cavitation is regarded as the continuous accumulation process of the steam phase content in the mixed fluid, the physical essence is better met, and therefore the forecasting result is more accurate.

A coating system includes a diffusion coating on a refractory metal or refractory metal alloy. The coating can be applied to a component such as a rocket engine component that includes a substrate including the refractory metal and is useful to protect the substrate from high temperature oxidation. The diffusion coating process employs an activator that includes a compound of the metal to be diffused into the surface of the substrate and is a vapor phase process in which the vapor includes metal from the activator and additional from the metal source being activated. Aluminum trifluoride can be used to activate an aluminum metal source to form an aluminide coating on a refractory metal-based alloy, such as a niobium alloy.

The utility model provides a heating cavity for off-line gas phase welding. The heating cavity for off-line gas phase welding comprises a placing frame, a cavity body, a cavity cover and a lifting mechanism, the top of the cavity is open, the bottom of the cavity cover is open and corresponds to the cavity, and the placing frame is connected to the bottom of the cavity cover in a sliding mode; and the lifting mechanism is used for driving the cavity cover to execute a lifting action so as to be far away from or close to the cavity. The placing frame moving along with the cavity cover is used for containing workpieces, operation is easy and convenient, the workpieces can be rapidly taken and placed when the cavity cover is lifted, and the workpiece feeding and discharging efficiency is improved; when the workpieces are manually taken and placed, the workpieces do not need to stretch into the cavity, the operation risk is reduced, and the feeding and discharging operation safety is guaranteed; and meanwhile, the workpiece is located in the upper space in the heating cavity through the arrangement of the containing frame, the workpiece is prevented from making direct contact with high-temperature gas-phase liquid at the bottom of the cavity or liquefied gas-phase liquid obtained after heat absorption and condensation, the phenomenon that the workpiece is heated unevenly in the welding process is effectively prevented, and the welding quality of the workpiece is guaranteed.