277 results about "Low vacuum" patented technology

The invention discloses a multi-stage isolation high vacuum obtaining system of a neutral beam injection device and a control method, and relates to the field of nuclear fusion Tokamak vacuum pumping design. The low-temperature pump unit comprises a plug-in low-temperature pump in a neutral beam vacuum chamber, and the plug-in low-temperature pump is used for refrigerating and cooling liquid nitrogen and liquid helium to adsorb gas to realize vacuum pumping; the low-temperature pump preceding-stage air extractor unit comprises a molecular pump unit, a roots pump unit and a mechanical pump unit; an inlet of the molecular pump set is connected with the neutral beam vacuum chamber through a gate valve, and an outlet of the molecular pump set is connected with an inlet of the roots pump set through a forestage valve. An inlet of the roots pump set is connected with the neutral beam vacuum chamber through a preceding stage valve and a pre-pumping valve, and an outlet of the roots pump set is connected with the mechanical pump set through the preceding stage valve. By adopting a multi-stage vacuum shielding technology and a step-by-step start-stop strategy, step-by-step transition from low vacuum to high vacuum and from high vacuum to low vacuum can be efficiently, stably and reliably realized, and an air extractor unit and a vacuum environment are protected from being polluted.

The invention discloses an energy-saving type vacuum cabinet and a using method thereof, and relates to the technical field of vacuum, the energy-saving type vacuum cabinet comprises a mounting cabinet body, a first partition plate is fixedly mounted in the mounting cabinet body, a second partition plate is fixedly connected in the mounting cabinet body, a sealing plate is mounted on the front surface of the mounting cabinet body, and the sealing plate is used for sealing a vacuum chamber a and a vacuum chamber b respectively; the vacuum pump set is installed at the bottom of an inner cavity of the installation cabinet body, the communicating pipe set is arranged among the vacuum pump set, the vacuum cavity a and the vacuum cavity b, and the vacuum cavity a and the vacuum cavity b form a negative pressure auxiliary source through the communicating pipe set. According to the invention, by utilizing the cooperative use mode of the mounting cabinet body, the vacuum pump set and the connecting pipe set, when the vacuum pump set performs vacuum negative pressure operation on the vacuum chamber a or the vacuum chamber b, the vacuum chamber a and the vacuum chamber b can be a negative pressure auxiliary source under the action of the connecting pipe set, so that the energy consumption during the operation of the vacuum pump set is reduced, and the energy consumption is further reduced.

The utility model discloses an electrostatic vacuum plate structure and a filling type electrostatic vacuum plate, and relates to the field of vacuum plates, the electrostatic vacuum plate structure comprises an upper vacuum plate and a lower vacuum plate, the space between the two vacuum plates is in a vacuumized state to form a vacuum cavity, and the two ends of the vacuum cavity are subjected to heat edge sealing treatment; the upper vacuum plate, the lower vacuum plate and the sealing edges at the two ends are attached through flexible insulating aluminum plastic films containing PTFE layers; inner-layer aluminum foils are pasted on the upper vacuum plate and the lower vacuum plate in the vacuum cavity respectively, the two inner-layer aluminum foils sense same-polarity negative static electricity, external air pressure is resisted through electrostatic repulsive force, and the thickness of the vacuum cavity is maintained to be in the preset size. Compared with a traditional glass fiber vacuum plate, heat transfer of an inner core material is avoided, the heat conductivity is reduced, the thickness of the vacuum plate can be reduced to be within 0.5 mm, high-performance heat-insulation ultrathin performance is achieved, a hard plate is changed into a flexible film material, and the fitting adaptability of a product on different surfaces is greatly improved.

The invention discloses a plasma-assisted surface activation method. The method comprises the following steps: placing a material matrix in a reaction cavity, vacuumizing, introducing oxygen and inert gas, exciting a radio frequency power supply and a microwave power supply to form multi-frequency composite plasma, and treating the material. The physical bombardment of the radio frequency plasma and the chemical activation of the microwave plasma have a synergistic effect, and deep cleaning and efficient modification of the surface of the material are realized in a low-vacuum environment. The surface water contact angle of the treated material is reduced to 35 degrees or below, the adhesive force of a coating reaches 0-1 level, the tensile shear strength is improved to 22.5 MPa or above, the problems that a traditional surface treatment method is unstable in effect and insufficient in modification depth are effectively solved, and the surface treatment method has the outstanding advantages of being high in treatment efficiency, uniform and lasting in modification effect, environmentally friendly and the like.

A kind of vacuum system for nanodose detector gas density precision control belongs to ionizing radiation nanodose measurement field.The present application includes vacuum pump group unit, vacuum degree detection unit, logic control unit.The present application is aimed at the requirement of nanodose detector to vacuum degree and gas concentration, and realizes that working air pressure is in 1Torr by the pump group in vacuum system and the cooperation of PLC logic control and data monitoring, and gas pressure control precision reaches 0.01Torr.The system can provide ionizing radiation gas and low vacuum environment for nanodose detector, ensure that nanodose detector measurement signal is accurate and stable.The ionization degree of nanodose detector depends on the vacuum degree in cavity, and the vacuum degree of cavity depends on the concentration of gas in sensitive volume.The present application has the advantages of high precision, high accuracy, high reliability and the like.Through the present application, the vacuum environment of nanodose detector can be constant and sensitive gas is single, which can support the accurate measurement of nanodose detector.

The utility model discloses a vacuum energy-saving generator, and relates to the technical field of vacuum pumps. The device is installed at the air outlet end of the vacuum pump and comprises a one-way valve, a sleeve and a vacuum generator, the one-way valve is located in the sleeve and divides the sleeve into an air inlet end and an air outlet end, the air inlet end of the sleeve is communicated with the air outlet end of the vacuum pump, and the air inlet end of the vacuum generator is located outside the sleeve and used for introducing high-speed flowing air. The air outlet end of the vacuum generator penetrates into the cavity of the air inlet end of the sleeve, the one-way valve is provided with a first exhaust port, the air outlet direction of the air outlet end of the vacuum generator is aligned with the first exhaust port of the one-way valve, and high-speed flowing air is ejected out through the air outlet end of the vacuum generator and then is exhausted through the first exhaust port of the one-way valve. The exhaust pressure of the vacuum pump is reduced, and the energy-saving effect is achieved.

The utility model relates to the field of special metallurgy, and discloses a waste discharge port structure of a vacuum induction melting furnace, which is characterized in that a gas path gas inlet is connected with a waste gas exhaust port of the vacuum induction melting furnace, and a gas outlet is connected with a vacuum pump through a pipeline; the drawing and inserting type first-stage filter is a high-temperature-resistant filter and is inserted into the gas path on one side of the gas inlet of the gas path; the cooling assembly is arranged in an air path between the first filter and the second filter in the air flow direction. The drawing and inserting type secondary filter is inserted into the gas path on one side of the gas outlet of the gas path; and the turbulent flow piece is formed on the inner wall of the gas path and / or the outer wall of the cooling assembly and used for increasing the heat exchange area and prolonging the waste gas passing time of the vacuum induction melting furnace. The service life of the vacuum pump can be effectively prolonged, and the failure probability of the vacuum pump is reduced.

This utility model discloses a vacuum pump with vibration reduction and noise reduction functions, including a vacuum pump body, and a vibration damping base installed at the bottom of the vacuum pump body. The vibration damping base can reduce the vibration of the vacuum pump body during operation, thereby reducing the noise generated by the vibration of the vacuum pump body. A noise reduction shell is installed on the outside of the vacuum pump body, which can reduce the noise generated by the vacuum pump body during operation. An air filter device is installed at the air inlet of the vacuum pump body, which can filter the air entering the vacuum pump body. The air filter device consists of a filter device shell and a metal filter plate. The metal filter plate is inserted into the interior of the filter device shell through a filter plate insertion slot on the filter device shell. This structure makes the metal filter plate easy to disassemble and assemble, thereby facilitating quick cleaning of the metal filter plate.

The utility model discloses a gate valve for vacuum equipment, which comprises a fixed frame, a gate valve, a gate valve and a gate valve, the fixed frame is mounted at an opening of a process cavity in a matching manner, a gate plate matched with the opening in a covering manner is arranged in the fixed frame, and the gate plate moves in the fixed frame; when the door plate is completely moved into the fixed frame, the door plate covers the opening relative to the opening; and when the door plate is moved out of the fixed frame, the door plate is opened relative to the opening. According to the vacuum equipment, the door plate moves along one side of the horizontal direction of the fixed frame, so that the door plate is closed or opened relative to the opening of the process cavity, the overall height of the vacuum equipment is reduced, and the requirement for the vertical height of a plant is lowered.

The invention discloses a manufacturing process of a vacuum insulated panel with a low vacuum degree enhanced in a structure. The manufacturing process comprises the following steps: carrying out compression pretreatment on a core body; laying surface-coated fiber cloth on the upper surface and the lower surface of the core body subjected to compression pretreatment, and implanting web wires according to preset density through a web wire machine to form a plurality of reinforced web wires penetrating through the thickness direction of the core body; a barrier layer is arranged, covers the upper surface and the lower surface of the core body and is fixedly connected with the belly wire exposed out of the core body, so that a reinforcing structure for resisting compression and stretching in the direction perpendicular to the surface of the core body is formed in the core body; vacuumizing the core body with the barrier layer until the core body is in a low-vacuum state with absolute pressure of 1000 Pa to 10000 Pa, and performing airtight sealing to obtain the vacuum insulated panel; wherein the barrier layer is configured to be a structural layer capable of realizing airtight packaging. Therefore, the core body has the capability of actively resisting pressure before being packaged, the'bulge 'failure caused by the collapse of the core body structure is fundamentally avoided, and the durability of the product is improved by an order of magnitude.

This invention discloses a low-vacuum laser welding device for medium-thick aluminum alloy plates, belonging to the field of metal welding technology, aiming to solve the problems of prominent porosity defects and insufficient mechanical properties in the welding of medium-thick aluminum alloy plates. The device consists of a laser cleaning and oscillating welding integrated module, a low-vacuum welding chamber module, a control system, and a detection module. The laser cleaning module uses a pulsed fiber laser to remove the oxide layer at an optimal energy density of 13.24 J / cm² under nitrogen protection, reducing the surface oxygen content to 9.66%. The low-vacuum welding chamber module constructs a negative pressure environment of 10²-10³ Pa to suppress plasma plumes. The oscillating laser welding module optimizes the stirring of the molten pool by achieving circular oscillation with a frequency of 80 Hz and an amplitude of 1 mm. The control system coordinates and regulates the parameters of each module, and the detection module monitors the weld quality in real time. This device reduces the weld porosity to below 0.032% and the tensile strength to 388.62 MPa (83.16% of the base material), making it suitable for welding medium-thick aluminum alloy plates for aerospace applications.

The application discloses a method for determining the condensation temperature of nitrogen under low vacuum pressure, in which, in one test, the total pressure at the inlet of a nozzle is kept unchanged through pressure control, the total temperature at the inlet of the nozzle is first adjusted to a higher total temperature through temperature control, and then the total temperature at the inlet of the nozzle is gradually reduced according to certain temperature intervals, the total pressure at the inlet of the nozzle, the total temperature at the inlet of the nozzle and the pitot pressure at the outlet of the nozzle are monitored in real time during the operation of the wind tunnel, and the condensation temperature of nitrogen under low vacuum pressure is determined through comprehensive analysis of the above data. The method can accurately determine the condensation temperature of nitrogen under low vacuum pressure, and makes up for the deficiencies of the theoretical formula and the traditional test acquisition method. The result can be used to reasonably determine the total temperature of a hypersonic low-density wind tunnel, which can not only reduce the design difficulty of the heater itself, but also reduce the overall energy supporting scale of the wind tunnel.

The utility model discloses a multi-station water-cooling die frame which comprises an upper die plate, an upper vacuum channel, a fixing column, an upper die sleeve, a lower die sleeve, a lower vacuum channel, a lower die plate, an oil removing suction cup and a multi-station die, the upper die sleeve is matched with the lower die sleeve, the upper vacuum channel is arranged on the upper die sleeve, the upper die sleeve is connected with the upper die plate through the fixing column, and the lower vacuum channel is arranged on the lower die sleeve. A lower vacuum channel is arranged below the lower die sleeve, and the lower die sleeve is connected with the lower die plate through a fixing column. A water inlet and a water outlet are formed in the side edge of the upper die sleeve and the side edge of the lower die sleeve respectively, a multi-station die is arranged in the lower die sleeve, and an oil removing suction cup is arranged on the multi-station die. Efficient cooling and high-quality forming are achieved through cold water circulation and a vacuum system, the multi-station design and the oil removal suction cup are combined, the production efficiency is remarkably improved, product pollution is prevented, the structure is reasonable, and the application range is wide.

This invention belongs to the field of egg product preparation technology, specifically relating to a pre-prepared salted duck egg, salted duck eggs, and a rapid pickling method. The rapid pickling method for salted duck eggs includes: (1) pre-treating duck eggs by immersing them in an organic acid solution; (2) immersing the pre-treated duck eggs in a pickling solution and pickling them using a vacuum pulsation method to obtain the pre-prepared salted duck egg; wherein, the vacuum pulsation method is: the vacuum degree of the pickling system is periodically alternating between high vacuum degree and low vacuum degree, the high vacuum degree is not higher than -0.08MPa, and the low vacuum degree is not lower than -0.05MPa. This invention, through vacuum pulsation technology combined with organic acid pre-treatment, achieves an oil yield of 66.5% in salted duck egg yolks and a salt content of 7.8% in egg whites within 20 days, and enriches DHA to 1434.2mg / kg and EPA to 78.0mg / kg, realizing a synergistic effect of shortening the pickling cycle and improving product quality.

The invention relates to the technical field of ink-jet printing machines, in particular to an ink-jet printing machine for cheese packaging, which comprises a conveyor belt, a packaging bag, a shell and a spray pipe arranged on one side of the shell, and further comprises a storage tank arranged in the shell and used for storing ink, and a stirring plate arranged in the storage tank. The stirring plate rotates in a low-vacuum environment to generate strong centrifugal force, bubbles in the ink are forced to separate and float upwards, the problems of nozzle blockage, ink interruption, code spraying fuzziness and the like are greatly reduced, the separated bubbles are actively broken in combination with alcohol atomization spraying of the bubble eliminating part, the ink purity is further ensured, and the ink quality is improved by maintaining the stable low-pressure environment in the storage tank. The bubble generation tendency is reduced, bubble floating separation is accelerated, the bubble removing efficiency is improved, the operation convenience is ensured through the design of a material opening threaded sealing cover, meanwhile, air entering and ink volatilization are isolated, and the pressure and component stability in the tank are maintained.

The invention discloses a low-gas-consumption vacuum breaking end effector of a reused vacuum pump and a vacuum breaking method, and belongs to the field of logistics automation. The problems that an existing actuator depends on an additional positive pressure air source, energy consumption is high, the structure is redundant, and old equipment transformation compatibility is poor are solved. The actuator comprises a suction cup connecting plate, a vacuum adsorption assembly, a mechanical arm connecting structure, a vacuum pump, a first stop valve, a second stop valve, an air distribution block and the like, the gas distribution block is provided with a main gas inlet and an independent gas outlet, the tail gas pipeline is connected with the second stop valve and the gas distribution block, and the three-way gas path connector is communicated with the gas distribution block. According to the vacuum breaking method, gas paths are switched through the stop valves, vacuumizing is conducted in the adsorption stage, the vacuum pump is reused as a channel in the release stage, and atmosphere is subjected to vacuum breaking through a short path. The device is low in gas consumption, high in vacuum pump utilization rate, simple in structure, adaptive to upgrading of old equipment, capable of meeting the high-speed sorting requirement and high in practical value.

The application discloses a method for realizing TGV high-conductivity copper-clad by using a magnetic filtering vacuum arc metal film, and specifically comprises the following steps: S1, ultrasonic cleaning is performed on a glass through-hole substrate; S2, sub-etching cleaning treatment and activation of a substrate surface are performed on the glass through-hole substrate under a vacuum environment; S3, a Ti film layer is deposited on the glass through-hole substrate after the treatment in S2 by using a magnetic filtering vacuum cathode arc method; and S4, a Cu film layer is deposited on the Ti film layer under a low vacuum environment. By using the method provided by the application, a Ti undercoat layer is first deposited, the problem of poor adhesion between Cu and a glass substrate is solved, then copper-clad deposition is performed, in addition, the glass substrate can be conductive after Ti plating, so that the bias voltage can be increased, the energy of Cu ions entering the hole is larger, the thickness of the film plated on the hole wall is improved, the adhesion is stronger, and the conductivity is improved.

The application relates to a carbonate double-cluster isotope sample preparation device, a preparation method and a detection system in the technical field of stable isotope detection, which comprises an automatic sample acidolysis reactor, a balanced gas quartz tube breaking device, a purification unit and a collection unit; a first low-vacuum pumping unit for purifying the automatic sample acidolysis reactor or the balanced gas quartz tube breaking device, a second low-vacuum pumping unit and a high-vacuum pumping unit for purifying the purification unit or the collection unit, and the automatic sample acidolysis reactor can pre-store two or more samples and sequentially perform acidolysis reaction on the samples. The carbonate double-cluster isotope sample preparation device, the preparation method and the detection system can realize full-automatic sample preparation, save manpower, reduce human errors and errors, and improve sample output rate.

This disclosure provides a vacuum filtration structure and a vacuum die-casting machine. The vacuum filtration structure includes a vacuum valve, a vacuum valve connector, and a filter assembly connected in series. One end of the vacuum valve connector is fixed to the exhaust port of the vacuum die-casting machine and communicates with the exhaust port. The vacuum valve is installed at the other end of the vacuum valve connector. The filter assembly is installed and fixed between the vacuum valve and the vacuum valve connector. The filter assembly includes an aluminum melt barrier, which blocks the aluminum melt. The aluminum melt barrier has a plurality of first filter holes, each with a pore size of 30μm-100μm. This vacuum filtration structure not only reduces the maintenance cost of the vacuum die-casting machine but also improves its production efficiency.

The utility model relates to the technical field of vacuum melting, in particular to a protection device for magnesium alloy vacuum melting, which comprises a two-stage rotary vane vacuum pump, a roots vacuum pump, a low-vacuum electromagnetic pressure difference inflation valve, a vacuum stop valve, a vacuum pipeline, a pressure air storage tank and a vacuum ball valve. A low-vacuum electromagnetic pressure difference inflation valve is connected between the two-stage rotary vane vacuum pump and the roots vacuum pump, a vacuum stop valve is connected above the roots vacuum pump, the top of the vacuum stop valve is connected with a vacuum pipeline, the right side of the vacuum pipeline is connected with a pressure air storage tank, and the right side of the pressure air storage tank is connected with a vacuum ball valve. And meanwhile, high-temperature magnesium liquid or gas is prevented from entering the two-stage rotary vane vacuum pump and the roots vacuum pump, so that the overall safety of the device is improved.

The utility model provides an electric vacuum pump which comprises an eccentric shaft provided with at least one eccentric part; the near end of each connecting rod is connected with one eccentric part; the far end of each connecting rod is connected with one piston through one connecting assembly; the connecting assembly comprises a pin and a second needle bearing, the first end of the pin is connected with the far end of the connecting rod, the second end of the pin is connected with the piston, and the second needle bearing is arranged between the second end of the pin and the piston. The needle bearings are used for replacing bushings, and gaps between the pins and the second needle bearings are small, so that the connecting stability among the connecting rod, the piston and the second needle bearings can be improved, the axial run-out problem of the connecting rod can be solved, the influence of run-out of the connecting rod on the needle bearings at the eccentric part is reduced, and the service life of the connecting rod is prolonged. Working reliability of the electric vacuum pump is improved, and noise during operation of the vacuum pump is reduced.

The utility model relates to a kind of vacuum drying device and flexible perovskite battery roll-to-roll manufacturing equipment, vacuum drying device includes upper vacuum cavity, lower vacuum cavity, negative pressure support mechanism and several guide vanes, upper vacuum cavity and lower vacuum cavity are opposite and form the narrow slit passage for flexible substrate to pass through in middle, negative pressure support mechanism is located in lower vacuum cavity and its support surface is with narrow slit passage equal height, several guide vanes with angle can be adjusted in 0 °-45 ° range are equipped in upper vacuum cavity. Device is through guide vane and is optimized by air flow and makes flexible substrate stable by negative pressure support mechanism, realize the high-quality continuous preparation of perovskite layer. Equipment includes the roll-off device, slit coating device, vacuum drying device, high-temperature annealing device and winding device arranged in sequence. Equipment integrates slit coating, vacuum drying and high-temperature annealing function, especially suitable for efficient, low-cost, large-scale industrial production flexible perovskite thin-film battery.

This invention discloses a vacuum-assisted homogenization and temperature-controlled 3D printing method and apparatus for irregularly shaped viscoelastic propellants, belonging to the field of additive manufacturing technology for energetic materials. The vacuum-assisted homogenization and temperature-controlled 3D printing method for irregularly shaped viscoelastic propellants achieves online degassing and precise temperature control of the slurry in a closed vacuum environment through synergistic physical field control. The technical solution of this application has the following technical effects: it abandons the inert gas protection method that may introduce new gas sources, and adopts a synergistic physical degassing mechanism based on low vacuum negative pressure, supplemented by ultrasonic vibration and pulsed vacuum fluctuations. The stable negative pressure environment provides a continuous driving force for the escape of gas inside the slurry; ultrasonic vibration acts on the slurry, which can destroy the adhesion state of microbubbles and promote their aggregation; pulsed vacuum fluctuations cause the bubbles to be in a periodic expansion and contraction state, thereby accelerating their instability and rupture. The above three physical fields cooperate and work synergistically.

The utility model discloses a three -section type conical screw rotor, three -section type conical screw rotor is divided into suction section, compression section and exhaust section in proper order along screw axial direction, the suction section is equal cross section and equal pitch along screw axial direction, the compression section adopts and is variable cross section and variable pitch along screw axial direction, the exhaust section is equal cross section and equal pitch along screw axial direction, the cross section width of suction section along screw axial direction is greater than the cross section width of exhaust section along screw axial direction, the end face profile equation of each section is same, and all are by five curves of abutting together closed, and the five curves include involute section AB, addendum circle arc section BC, long amplitude outside cycloid section CD, dedendum circle arc section DE and point conjugate curve section EA. The utility model also provides a vacuum pump. The device of the utility model can effectively reduce the noise of vacuum pump, reduce the clearance backflow, thereby improve its reliable stability and practical life.

The invention provides an electroplating device for vacuum sucking and filling holes and a working method thereof.The electroplating device comprises a truss arranged along the X axis, sliding plates are arranged on the truss in a sliding mode, at least two sliding plates are arranged on the truss, an upper vacuum cover is arranged below the sliding plates, and the position of the upper vacuum cover can be adjusted through movement in the Z-axis direction; a lower vacuum cover is arranged below the truss correspondingly, any upper vacuum cover and the lower vacuum cover can form a vacuum cavity, a clamp used for installing a base material is arranged in the upper vacuum cover, a clamping assembly capable of unfolding the base material is further arranged in the upper vacuum cover, and a sputtering source is arranged in the lower vacuum cover; a vacuum cavity can be formed between the upper vacuum cover and the lower vacuum cover corresponding to the upper vacuum cover, and the base material can be unfolded through the clamping assembly, so that uniform coating on the surface of the base material is realized.

The invention belongs to the technical field of manipulator automatic control, and discloses a manipulator grabbing and releasing control valve which comprises a connecting plate, and vacuum generators are installed and connected to the top of the connecting plate at equal intervals. Core components such as the vacuum generator, the direct-acting electromagnetic valve and the terminal strip are integrated through the connecting plate, traditional distributed pipeline connection is replaced, and pipeline redundancy is reduced; a valve element of the direct-acting type electromagnetic valve is directly driven by electromagnetic force and a reset spring and does not need to depend on medium pressure difference, the response time from power obtaining to vacuum generation and from power failure to automatic vacuum breaking is shortened, and the single-time grabbing and releasing circulation efficiency of the mechanical arm is greatly improved. The vacuum generator can work within the wide pressure range of the positive pressure ranging from 1 MP to 0.8 MP or the negative pressure ranging from 10 < 2 > KP to 0.1 MP, the grabbing requirement under the conventional atmospheric environment can be met, the vacuum generator can also adapt to low-vacuum scene operation, the problem that a traditional vacuum generator is high in fault rate under the special environment is solved, and actual application and operation are facilitated.

The invention provides a vacuum insulation board, a preparation method thereof and refrigeration equipment. The vacuum insulation board comprises a first membrane material, a second membrane material and a plurality of supporting core materials, and the first membrane material and the second membrane material are oppositely arranged; the first membrane material is provided with a plurality of first grooves which are recessed in the direction away from the second membrane material, the second membrane material is connected with the peripheries of the first grooves in a sealed mode to form a plurality of vacuum cavities, a supporting core material is arranged in each vacuum cavity, and the two opposite ends of each supporting core material abut against the first membrane material and the second membrane material respectively. According to the vacuum heat preservation plate, gas convective heat transfer and gas heat conduction can be eliminated, so that the heat conductivity coefficient of the vacuum heat preservation plate is reduced, and the heat insulation and heat preservation performance of the vacuum heat preservation plate is effectively improved.

The invention discloses an internal water pressure or low vacuum shield tunnel structure performance test device and method. The device comprises a shield pipe section, a steel outer support, a hydraulic bag, a steel inner support, a cover plate, a sealing support and a connector. The hydraulic bag applies continuous distribution pressure to the outer side of the pipe section to simulate external water and soil load; the steel inner support and the inner wall of the pipe section form a cavity, and two ends of the steel inner support are sealed by the cover plate and the sealing support respectively to form a closed cavity; the connector can inject water into the cavity to establish positive pressure or exhaust air to establish negative pressure, and the inner side inner pressure or low vacuum working condition is achieved. The same device can complete the structural performance test under the action of outer side continuous loading and inner side positive / negative pressure coupling, the loading condition is continuous, the sealing is reliable, and the working condition switching is convenient.

The present application relates to smelting furnace technical field, specifically to a kind of vacuum metal smelting furnace, including the main furnace body of top being equipped with top cover, rotating seat and crucible, rotating seat is through type rotation installation on main furnace body, rotating seat is connected with electromagnetic coil in the end portion in main furnace body, crucible is placed in electromagnetic coil, vacuum feeding mechanism is equipped on top cover, vacuum feeding mechanism includes cylinder seat, stem and driving device;Cylinder seat is installed on top cover, cylinder seat is sequentially equipped with sequentially communicated feeding cavity, vacuum cavity and feeding cavity from top to bottom in it, stem is movably matched and installed in cylinder seat.The cavity structure in cylinder seat and the up and down movement of stem are utilized, cooperate sealing ring and solenoid valve control, the switching of three states of feeding, storage and feeding is realized, raw material is temporarily stored in the annular storage cavity after pre-vacuumizing, then is fed into crucible as required, feeding process does not need to open furnace, maintains the stability of vacuum degree in furnace, reduces vacuum energy consumption.

This invention discloses a low-selectivity vacuum dehumidification membrane and its preparation and testing methods. The low-selectivity vacuum dehumidification membrane of this invention has a four-layer structure, including a support layer, a hydrophobic layer, a hydrophilic layer, and an active layer. The hydrophobic layer is placed on the support layer, the hydrophilic layer is adhered to the hydrophobic layer, and the active layer is uniformly coated on the hydrophilic layer. The performance of the low-selectivity vacuum dehumidification membrane can be tested using the testing method proposed in this invention. The low-selectivity vacuum dehumidification membrane of this invention enables vacuum membrane dehumidification systems to operate under the drive of a low-power vacuum pump, which is expected to reduce the noise of the vacuum membrane dehumidification system and improve the system energy efficiency. The testing method of this invention solves the problem of difficulty in measuring the water vapor partial pressure on the permeate side, making the testing process simple and feasible.