45results about How to "Reduce the compression ratio" patented technology

The utility model relates to the technical field of cooling fans, in particular to a reversing fan base body structure suitable for different hydraulic pressures, which comprises a cylinder body, a piston and a reset spring. The cylinder body is provided with a middle boss and an outer boss, and an annular cavity is formed in the radial outer side of the outer boss; the piston comprises a middle roundabout and an outer roundabout, the middle boss is sleeved with the middle roundabout, the outer boss is sleeved with the outer roundabout, sealing rings are arranged on the inner wall of the outer roundabout and the outer wall of the outer boss, the end face of the middle roundabout is closed, and a first hydraulic cavity is formed between the end face of the middle roundabout and the end face of the middle boss. A second hydraulic cavity is formed between the inner end face of the outer roundabout and the end face of the outer boss; one end of the reset spring is connected to the outer side of the middle roundabout in a sleeving mode and abuts against the outer end face of the outer roundabout. The reversing fan structure can adapt to vehicles with different hydraulic pressures.

The invention discloses a carbon dioxide multi-stage compression energy storage and release system which comprises a control unit, an energy storage and release water side circulation loop, an energy storage and release carbon dioxide side circulation loop and a compression type storage tank connected between the control unit and the energy storage and release water side circulation loop and used for storing water and carbon dioxide at the same time. The compression type storage tank is used for providing a high-pressure medium for the energy storage and release water side circulation loop and the energy storage and release carbon dioxide side circulation loop. Water is used for preliminarily compressing carbon dioxide, the compression ratio of a compressor in the system is greatly reduced, and therefore compression energy consumption and equipment cost are reduced. Meanwhile, the pressure of carbon dioxide is utilized to extrude the water chamber and drive the hydro-generator to generate electricity, the advantages of being stable in performance, low in cost, short in recovery period and the like are achieved, peak load shifting can be achieved, renewable energy sources can be distributed and stored, and heating and refrigerating can be achieved. The whole system has the advantages of safety, high efficiency, high energy density, flexible energy storage and release, high energy utilization rate and the like.

The invention provides an effective gas recovery method and device for a low-temperature methanol washing device, and the method comprises the following steps: raw material gas and lean methanol are subjected to desulfurization and decarburization in a shift gas washing tower, qualified purified gas is obtained at the top of the shift gas washing tower, and methanol without hydrogen sulfide is obtained at the middle part of the shift gas washing tower; methanol containing hydrogen sulfide is obtained from a tower kettle of the shift gas washing tower; and the hydrogen sulfide-free methanol and the hydrogen sulfide-containing methanol are respectively subjected to gas stripping operation through high-pressure nitrogen, effective gases of hydrogen and carbon monoxide are recovered, and the obtained recycle gas is returned to the raw material gas. A high-pressure nitrogen gas stripping mode is adopted to replace a medium-pressure flash evaporation mode to recycle effective gas, the concentration of the effective gas in the circulation gas generated in the process is increased by about one time, the pressure of the obtained circulation gas is close to that of raw gas, the compression ratio of a compressor is greatly reduced, and the energy consumption is reduced. By adopting high-pressure nitrogen gas stripping, the flow of circulating gas can be greatly reduced, and the power consumption of the compressor is reduced.

The invention provides a compression garbage truck loading system, a control method and a storage medium, the system comprises a compression mechanism and a push shovel mechanism, and the compression mechanism comprises a sliding plate and a sliding plate oil cylinder used for driving the sliding plate; the push shovel mechanism comprises a push shovel, a push shovel oil cylinder used for driving the push shovel and a push shovel valve used for controlling the push shovel oil cylinder to retract, the system further comprises an oil pressure detection unit, a position detection unit and a control unit, and the oil pressure detection unit is used for detecting oil pressure information of a sliding plate oil cylinder in the garbage compression process of the sliding plate and uploading the oil pressure information to the control unit; the position detection unit is used for detecting the position information of the push shovel in the dustbin and uploading the position information to the control unit; the control unit is used for opening or closing the push shovel valve according to the oil pressure information and adjusting the back pressure of the push shovel oil cylinder according to the position information, it is guaranteed that the pressure of the push shovel oil cylinder is the maximum when the cylinder diameter is small and the pressure of the push shovel oil cylinder is the minimum when the cylinder diameter is large, and therefore the larger garbage compression ratio is obtained, and the garbage loading capacity of a single vehicle under the same volume is improved.

According to the waste heat recycling method and system for the organic liquid dehydrogenation process, the self-supply proportion of energy for preheating a liquid hydrogen-rich carrier is increased from less than 75% to complete coverage of energy consumption of a preheating section, the energy utilization rate of the technological process is greatly increased, supply of cold and heat public engineering is greatly reduced, and the operation cost is reduced. After pressurization and heat exchange, the waste heat source grade of a gaseous dehydrogenation product can be improved, the device can be flexibly matched with a demand end, the heat needed by reaction is reduced, and heat medium water is generated. And finally, the hydrogen obtained through separation has the pressure within a certain adjustable range, the pressurization requirement of a rear-end use scene can be met, and the equipment occupied area and the investment cost of rear-end hydrogen pressurization in a conventional process are greatly reduced. Compared with the traditional dehydrogenation process, the comprehensive energy efficiency of the process system is greatly improved, and the land occupation and operation energy consumption of the whole dehydrogenation process device are effectively reduced.

The present invention discloses a three-condition system with an ejector, aiming to provide a three-condition system in which a single-stage compression refrigeration system is used in air conditioning working condition, a quasi-two-stage compression refrigeration system with an ejector and intermediate air supply is used in ice making working condition, and a quasi-two-stage compression heat pump system with an ejector and intermediate air supply is used in winter heating working condition, so as to reduce the initial investment cost of the system, reduce energy consumption and operating costs, and save energy. The system includes a compressor with intermediate air supply, a four-way reversing valve, an outdoor heat exchanger, an indoor heat exchanger, an ice making evaporator, an economizer, an ejector, a throttling device, a regulating valve group and a plurality of valves. The switching of the single-stage compression refrigeration system, the quasi-two-stage compression refrigeration system with an ejector and the quasi-two-stage compression heat pump system with an ejector and intermediate air supply is realized by opening and closing a plurality of valves, thereby reducing the initial investment of the system.

The application discloses a machine head for manufacturing soft polytetrafluoroethylene insulated wire and a processing method thereof. The machine head comprises a connecting head in the machine head, a die core is arranged at the top of the connecting head through a die core base, a die sleeve is arranged outside the die core, a center tube is arranged at the bottom center of the connecting head, the machine head comprises two conical bodies with different angles, a bottom conical angle and a top conical angle, the angle of the top conical angle is smaller than that of the bottom conical angle, the wire bearing section of the machine head is horizontal to the die core base, the connecting head comprises two trapezoidal cones with different angles, a bottom conical angle and a top conical angle, the bottom conical angle is the same as the bottom conical angle, and the top conical angle is smaller than the top conical angle, a conductor anti-shaking device is arranged at the bottom of the center tube, the conductor anti-shaking device comprises arc-shaped groove wheels and springs, and the arc-shaped groove wheels are connected through a center rod. The steps are as follows: filling; center tube and die core related component installation; machine head and die sleeve installation; and pushing and extruding. The application can make the insulation layer outside the conductor more compact, and avoid the bending phenomenon of the conductor during processing.

The invention belongs to the technical field of hydrogen production through water electrolysis, and relates to a low-pressure-ratio energy optimization heat pump system and method for hydrogen production through water electrolysis. Comprising an oxyhydrogen gas-liquid separation unit, a heat pump compressor and an expansion machine, and the oxyhydrogen gas-liquid separation unit is connected with a hydrogen dryer through a hydrogen cooler; the oxyhydrogen gas-liquid separation unit is connected with the heat pump heat absorber through a circulating cooling water pipeline, the hydrogen cooler is connected with the refrigerating machine through a refrigerant pipeline, and the hydrogen dryer is connected with the steam generator through a hot water pipeline and a steam pipeline. The outlet of the heat pump compressor is sequentially connected with the steam generator and the inlet of the expansion machine through a hot heat pump working medium pipeline; the outlet of the expansion machine is sequentially connected with the refrigerator, the heat pump heat absorber and the inlet of the heat pump compressor through a cold heat pump working medium pipeline; and the hot and heat pump working medium pipeline and the cold and heat pump working medium pipeline are both connected with a heat regenerator. The pressure ratio of the heat pump compressor is reduced, the selection range of the heat pump working medium is enriched, and the energy utilization rate of the system is improved.

The invention relates to a method for quickly setting an experimental pressure, comprising a piston-type high-pressure container, an injection pressure gauge, and a capillary model; the top of the piston-type high-pressure container is connected to the inlet end of the capillary model via a pipeline, and the pipeline connecting the piston-type high-pressure container and the capillary model is provided with an injection pressure gauge and an injection valve; the lower part of the piston-type high-pressure container is connected to an electric pump; one end of a four-way valve is connected to a back-pressure pressure gauge, one end is connected to a back-pressure source container via a pipeline, one end is connected to a manual pump via a pipeline, and one end is connected to a pressure relief valve; a branch pipeline is connected to the pipeline between the four-way valve and the manual pump, one end of the branch pipeline is connected to the pipeline between the four-way valve and the manual pump, and the other end is connected to a nitrogen bottle; a back-pressure source inlet valve is provided on the pipeline between the four-way valve and the back-pressure source container, and a gas pressure reducing valve is provided on the branch pipeline; the invention has the characteristics of convenience, rapidity, safety and reliability.

The present invention discloses an application of an electric furnace wire rod in the production of steel cords, comprising: (1) rough drawing and medium drawing of the electric furnace wire rod to obtain medium-drawn steel wire with a diameter of 1.15 mm to 2.20 mm; (2) quenching the medium-drawn steel wire by AQ liquid; (3) pickling, brass plating, and galvanizing the medium-drawn steel wire, and then subjecting the medium-drawn steel wire to MF diffusion, so that copper and zinc atoms diffuse mutually to form a brass alloy layer, and the copper content in the plating layer is 63.5±2.5%; (4) drawing the obtained brass-plated steel wire by a wet drawing method to a single wire with a diameter of 0.18 to 0.38 mm for application in the production of steel cords. It can not only replace 72C and 82C steel grades, but also solve the problem of high wire breakage rate caused by increasing the diameter of 72Cr brass-plated steel wire to meet customer needs. That is, by reducing the diameter of the brass-plated steel wire, the wire breakage rate is reduced and the yield rate is improved while ensuring that the breaking tensile force meets customer needs. At the same time, the extensive use of EAF82C electric furnace wire rod can reduce the switching of different wire rod grades and reduce production complexity.

The utility model belongs to the technical field of power machines, and particularly relates to a general power machine crankshaft which comprises a crankshaft main journal and a flying disc, an oil injection hole is formed in the crankshaft main journal, a balance weight crank is fixedly installed at one end of the crankshaft main journal, and a connecting rod bent neck is fixedly installed on one side of the balance weight crank. And a crankshaft upper bearing bush is rotationally mounted outside the crankshaft main journal. The rolling balls are installed in the bearing in a circular array mode, friction of the crankshaft to a flying disc can be reduced, so that the transmission efficiency is improved, the side face of the balance weight crank is in a blade shape, air resistance of the balance weight crank can be reduced, crankshaft power loss is reduced, the transmission efficiency of the crankshaft is improved, and the service life of the crankshaft is prolonged. The second fixing rod penetrates through the crankshaft upper bearing and the crankshaft lower bearing, and the second fixing rod is in threaded connection with the interiors of the crankshaft upper bearing and the crankshaft lower bearing, so that the crankshaft upper bearing and the crankshaft lower bearing can be fixed through the second fixing rod.

The invention relates to a self-adaptive quantum random number generation method based on real-time entropy estimation, and belongs to the technical field of quantum random number generation. According to an existing integrated quantum random number generator, due to the non-stationary characteristic of a physical entropy source, the entropy rate dynamically drifts, and after-processing parameters are fixed, randomness safety and generation efficiency are difficult to guarantee at the same time. According to the method, the state transition probability of the original random bit stream is counted in real time, the confidence interval correction is introduced to calculate the minimum entropy, the input bit width is dynamically adjusted accordingly, the Toeplitz matrix is reconstructed for random extraction, and self-adaptive adjustment of the compression ratio is achieved. According to the method, the compression ratio is increased to ensure the security of the output random number when the entropy source quality is reduced, and the compression ratio is reduced to improve the generation efficiency when the entropy source quality is improved, so that the dynamic balance between the randomness security and the generation efficiency is realized on the premise of keeping integration and low cost.

The application relates to a high-speed stretching controllable spring for bicycle seat adjustment, which comprises a starting top rod, a hollow piston rod, a framework guide, a sealing ring, a pressurized air cavity, a positioning groove, a piston assembly, an oil cavity and a cylinder barrel, the cylinder barrel is divided into the pressurized air cavity and the oil cavity by the positioning groove, the framework guide is arranged at one end of the cylinder barrel, the sealing ring is arranged on one side of the framework guide, the piston assembly is arranged at one end of the oil cavity, one end of the hollow piston rod is connected with the piston assembly, the other end of the hollow piston rod penetrates through the framework guide and extends to the outside of the cylinder barrel, the starting top rod is arranged in the hollow piston rod in a penetrating mode, a piston valve needle is arranged in the piston assembly, and the piston valve needle is connected with the starting top rod; the application solves the problem of slow seat adjustment stretching speed, improves the adjustment response efficiency, reduces the product size, optimizes the installation adaptability, reduces the compression ratio and reduces the operation force change.

The invention relates to the field of refrigeration equipment, in particular to a refrigerator, a control method and a controller thereof. The refrigerator comprises a double-suction compressor and a controller, the double-suction compressor comprises a first suction inlet, a second suction inlet and an exhaust port, an outlet of a refrigerating chamber evaporator is connected with the first suction inlet through a first air return pipe, and an outlet of a freezing chamber evaporator is connected with the second suction inlet through a second air return pipe; the controller is used for controlling the operation of the double-suction compressor, so that a refrigerant exchanges heat through the refrigerating chamber evaporator and the freezing chamber evaporator respectively; when the temperature of the refrigerating chamber is smaller than or equal to the first preset temperature, the switch valve is controlled to be closed, and the double-suction compressor is controlled to increase the rotating speed, so that the heat exchange efficiency of the freezing chamber is improved, the temperature of the freezing chamber is reduced to the shutdown temperature of the double-suction compressor quickly, the running time of the double-suction compressor is shortened, and the power consumption of the refrigerator is reduced.

The invention discloses a hydrogen energy and natural energy heat pump heat supply and refrigeration integrated system and method, and relates to the technical field of hydrogen energy and natural energy heat pump heat supply and refrigeration integration. The heat pump heating module comprises the following steps that S1, carbon dioxide in air is absorbed through a refrigerant or the refrigerant and released into water; the carbon dioxide heat pump is used, and carbon dioxide is a clean refrigerant, has no destructive influence on the environment, is stable in chemical property, non-combustible, not easy to decompose at high temperature, does not generate harmful gas, is non-toxic, reduces threats to people due to leakage, is good in fluidity and has a relatively high evaporation latent heat value; compared with conventional refrigerants, the compression ratio of carbon dioxide is much smaller than that of common refrigerants, high performance coefficient and mechanical efficiency can be achieved, the high condensing temperature enables the exhaust temperature of a compressor to be high, and water at the high temperature can be obtained.

The invention provides a heat pump air conditioning system, a control method of the heat pump air conditioning system and an air conditioner. The heat pump air conditioning system comprises a compressor, an outdoor heat exchanger, a gas-liquid separator and an indoor heat exchanger, and a communicating pipeline is arranged between a first air suction port of a first compression cylinder and a second air suction port of a second compression cylinder; an air supply pipeline is arranged between the third end of the gas-liquid separator and the second air suction port; a first control valve is arranged on the communicating pipeline, and a second control valve is arranged on the air supplementing pipeline; when the first control valve is in an off state and the second control valve is in an on state, the compressor runs in a parallel compression mode; when the first control valve is in the open state and the second control valve is in the open state, the compressor operates in a parallel compression mode. The problems that in the prior art, an air conditioner is poor in refrigeration effect in a high-temperature environment, the low-temperature heating capacity in winter is poor, the operation efficiency of a compressor is poor, and consequently the energy efficiency of the air conditioner cannot be guaranteed are solved.

The invention relates to a man-machine interaction image data compression strategy customization system. The system comprises a compression execution device, an information capturing device, a sequential upgrading device and an edge analysis device. According to the invention, a certain image compression ratio can be ensured while excessive wireless transmission data in man-machine interaction can be avoided.

The invention provides a gas compression type heat pump device system and method for producing steam through large-temperature-difference industrial waste heat. The gas compression type heat pump device system comprises a plurality of stages of compression assemblies, a heat regeneration device, an expansion device and a heat exchange device which are sequentially arranged in a communicating mode in the flowing direction of a gas working medium. A compression assembly connected with a first gas working medium outlet of the heat regeneration device is used as a first stage; a compression assembly connected with a second gas working medium inlet of the heat regeneration device is used as the last stage; the compression assembly comprises a compression device and an intermediate cooling device which are connected in sequence; the multiple stages of intermediate cooling devices are each provided with a first heat exchange fluid channel, and the first stage of intermediate cooling device is provided with a steam outlet. By arranging the multiple stages of compression assemblies, approximately isothermal gas compression and high-grade heat output are achieved, the large-temperature-difference low-grade industrial waste heat is used as a variable-temperature heat source of the heat exchange device in a combined mode, the high-temperature pump heat effect is achieved, and then high-temperature steam needed by the industry is obtained.

The invention relates to the technical field of shaft anti-freezing, and discloses an efficient anti-freezing air source heat pump and heat pipe heat exchanger coupled shaft anti-freezing heating device which comprises an air source heat pump, a heat pipe heat exchanger and a shaft, the air source heat pump comprises a compressor, a condenser, a standard throttling device and an evaporator, and the compressor is connected with the condenser; the condenser is connected with a standard throttling device, the standard throttling device is connected with the evaporator, and the evaporator is connected with the compressor; an outlet of the heat pipe exchanger is connected with a heat exchange pipe, the other end of the heat exchange pipe is connected with an inlet of the heat pipe exchanger, the heat exchange pipe is installed in the condenser, an electric fan is installed on heat exchange fins on one side of the heat exchange pipe, and heat exchange fins on the other side of the heat exchange pipe correspond to a shaft. Compared with a traditional device which needs to heat hot water and then heat fresh air, the heat exchange link is omitted, the condenser of the air source heat pump is subjected to phase-change heat exchange at the moment, the heat exchange efficiency is higher, and energy consumption of the water pump is reduced.

The utility model discloses a kind of gas suspension centrifugal water chiller unit, its compressor is gas suspension centrifugal compressor;The coolant inlet of condenser is connected to the outlet of compressor;The coolant outlet of condenser is two-way: first road connects the liquid inlet of economizer, second road is sequentially connected the inlet of ball valve and second expansion valve;The motor heat dissipation pipeline inlet of compressor is connected to the outlet of second expansion valve;The inlet of isolating valve is connected to the motor heat dissipation pipeline outlet of compressor;The top of evaporator is connected to the outlet of isolating valve;The outlet of economizer is two-way: liquid outlet connects the inlet of first expansion valve;Gas outlet connects the medium-pressure cavity of compressor;The coolant inlet of evaporator is connected to the outlet of first expansion valve;The inlet of compressor is connected to the coolant outlet of evaporator.Using the utility model, not only can significantly improve system efficiency, but also can utilize the high-efficiency cooling motor of system itself cold source, without external cooling system.

An internal combustion engine for achieving compression ratio and expansion ratio decoupling is characterized in that the internal combustion engine is composed of an independent compressor and an independent expansion machine, an intercooler and a combustion chamber are arranged between a compressor air cylinder and an expansion machine air cylinder, and the intercooler and the combustion chamber are connected through a pipeline and a valve system. Separation of the compressor from the expander decouples the compression ratio and the expansion ratio, thereby forming a low compression ratio and an ultra-high expansion ratio. For example, when the compression ratio is 10: 1, the expansion ratio can reach 30: 1. In particular, the internal combustion engine has a new combustion mode, which has a strong ability to resist knocking.

The present invention discloses a steam jet vacuum pump unit that utilizes process waste heat and exhaust steam waste heat, including: a hot water tank A warehouse, which is used to hold heat source water. A hot water tank B warehouse, which is used to hold sub-low temperature water. The steam jet vacuum pump unit is arranged in multiple stages and is connected in series from front to back. Each stage is composed of a condenser and a jet pump connected in series from front to back; wherein the outlet of the last-stage jet pump is connected to the hot water tank A warehouse through a pipeline, so as to introduce waste steam into the heat source water in the hot water tank A warehouse. An absorption refrigeration machine, the inlet and outlet ends of its evaporator are respectively connected to the hot water tank B warehouse and the hot water tank D warehouse pipelines to form a low-temperature water circulation channel, and low-temperature water is obtained at the outlet end after the low-temperature water is cooled therein. The vacuum pump unit utilizes the heat of the unpressurized waste steam to produce low-temperature water that cannot be stably supplied by the natural environment, and uses it as cooling water for the condenser, thereby saving working steam and cooling water.

The embodiment of the present application provides a model compression method, device, electronic device, storage medium and product, which relates to the field of deep learning technology. The method includes: for the same input data, using the model to be compressed and the quantization model for processing respectively; calculating the difference between the output data of the model to be compressed and the quantization model as the first difference corresponding to the quantization model; adjusting the quantization parameters of each network layer in the model to be compressed according to the first difference; calculating the continuous domain quantization bit width of the network layer based on the optimal quantization parameter of each network layer; determining the discrete domain quantization bit width that is larger than the continuous domain quantization bit width of the network layer and has the smallest difference with the continuous domain quantization bit width of the network layer from each discrete domain quantization bit width supported by the hardware platform where the model needs to be deployed; and determining the corresponding target compression model with the smallest second difference from each candidate compression model obtained by compressing using multiple sparsity combinations. The applicability of the model can be improved.

The utility model belongs to the technical field of flow batteries, and particularly relates to a flow battery with an obliquely arranged membrane. The flow battery stack comprises a diaphragm, an electrode frame and a bipolar plate, wherein the electrode frame and the bipolar plate are arranged in parallel; the electrode frame is provided with a hollow area, the bipolar plate, the diaphragm and the hollow area define an electrode containing space, and the electrode is arranged in the electrode containing space; a certain angle is formed between the diaphragm and the bipolar plate, so that the height of the electrode accommodating space is gradually increased along the flowing direction of the electrolyte, and the electrode compression ratio of the electrode is gradually reduced along the flowing direction of the electrolyte; the height of the electrode accommodating space is the vertical distance between the diaphragm and the bipolar plate. In the application, the contact resistance can be reduced at a place with a high compression ratio. And at a place with a low compression ratio, the electrolyte is quickly updated, so that the phenomenon of electrolyte insufficiency is improved.

The application relates to a scooter, a frame and a steering auxiliary return mechanism. The steering auxiliary return mechanism comprises a first connecting structure provided with a return ring groove; a fixed part is fixedly arranged on the inner wall of the return ring groove; the two ends of the fixed part are respectively provided with a first stop part and a second stop part along the circumference of the return ring groove; a return driving assembly is arranged in the return ring groove and comprises an elastic part; the elastic part is provided with a first end and a second end which are opposite to each other along the circumference of the return ring groove; and a sliding block is arranged in the return ring groove and located between the first end and the second end of the elastic part; the sliding block can slide along the return ring groove to switch between a return state and a deviated state; when the sliding block is in the return state, the first end and the second end of the elastic part are respectively in abutment with the first stop part and the second stop part; when the sliding block is in the return state, the first end or the second end of the elastic part can be moved along the circumference of the return ring groove to switch to the deviated state.

The present invention relates to the field of data processing technology, and in particular to an electronic contract maintenance management method and system based on big data, comprising the following steps: collecting electronic contract metadata in a data source, and sequentially cleaning, converting, compressing, merging, extracting features, and backing up the electronic contract metadata; performing data analysis based on the extracted features, and collating the analysis results to output electronic contract statistical data; when it is determined that the stability of maintenance management does not meet the requirements, adjusting the collection frequency of the electronic contract metadata; when it is determined that the validity of the storage space does not meet the requirements, determining the compression ratio of the electronic contract metadata; and re-determining the compression ratio of the electronic contract metadata based on the byte loss rate of the electronic contract metadata. The present invention achieves an improvement in the stability of maintenance management.

The invention belongs to the technical field of refrigeration preparation equipment, and particularly discloses a low-pressure-ratio centrifugal compressor and screw compressor series matched refrigeration system. A low-compression-ratio centrifugal compressor is used as a supercharging device matched with a main compressor (or a second-stage compressor), and three sections of different pressures including low pressure at an outlet of an evaporator, medium pressure at an inlet of the main compressor (or the second-stage compressor) and high pressure at an outlet of the main compressor (or the second-stage compressor) are formed by increasing the low-compression-ratio centrifugal compressor; the original process requirements of the refrigerating unit are met, and the air suction capacity of the main compressor (or called a secondary compressor) is improved through the air supply advantage of the low-compression-ratio centrifugal compressor under the low-temperature and low-pressure conditions. According to the invention, the centrifugal compressor is connected in series in the screw compressor refrigeration system for use. The compression ratio of the centrifugal compressor is ingeniously reduced, so that the centrifugal compressor meets the pressurization working condition of a refrigerating system of the screw compressor. Through the cooperation, the efficiency of the refrigerating system under the low-temperature and low-pressure working conditions is greatly improved.

The utility model discloses a large-displacement combined type high-pressure nitrogen supercharger which comprises a machine frame and a low-pressure nitrogen storage tank installed at the bottom of the machine frame, and a first V-shaped piston air compressor and a second V-shaped piston air compressor are installed on the two sides of the top end of the machine frame respectively. The air outlet end of the first V-shaped piston air compressor is connected with the air inlet end of the second V-shaped piston air compressor. According to the utility model, the two V-shaped piston air compressors are connected in series for pressurization, so that higher final pressure is realized, the requirements of special industrial processes, laboratory research or other use occasions needing extremely high gas pressure are met, and the system can meet wider pressure requirements; and meanwhile, the V-shaped piston air compressor I and the V-shaped piston air compressor II are connected in series, and compression is performed in stages, so that a relatively small compression ratio can be realized in each stage, and the power and energy required by each compressor are reduced.

The utility model provides a breathing air storage tank which comprises a metal tank body, a flexible air bag is arranged in the metal tank body, the flexible air bag divides the space in the metal tank body into an air cavity and a gaseous working medium cavity, the pressure of the air cavity is 0.7-3.5 Mpa, the pressure of the gaseous working medium cavity is the same as that of the air cavity, the air cavity is communicated with an air inlet and an air outlet respectively, and the air inlet is communicated with the air outlet. The gaseous working medium cavity is communicated with the working medium inlet and the working medium outlet. The gas working medium is dedusted in the metal tank at 0.7-3.5 Mpa, and compared with a normal-temperature and normal-pressure storage mode, the space occupied by the gas storage device is greatly reduced, so that the space cost is saved. Meanwhile, the cost of the air bag for air storage in the market is far higher than that of a metal tank body, the use amount of the air bag is reduced in the mode that the metal tank body can store pressurized air, and the overall cost of the air storage device is greatly reduced. In addition, the gaseous working medium in the breathing gas storage tank is in a pressurized state of 0.7-3.5 Mpa, so that the gaseous working medium is more convenient to pressurize again to liquefy the gaseous working medium.

The present invention discloses a hydrogen refueling station system in which on-site hydrogen production and externally purchased hydrogen are complementary, which includes an external hydrogen supply device, an on-site hydrogen production device, a hydrogen supply main road, a hydrogen supply branch road and a pressure regulating branch road, wherein the external hydrogen supply device is connected to the hydrogen supply main road, and the hydrogen supply main road is provided with a first valve, a first compressor and a hydrogen refueling device in sequence; one end of the hydrogen supply branch road is connected to the on-site hydrogen production device, and the other end is connected to the hydrogen supply main road, and a second compressor is provided on the hydrogen supply branch road. In the present invention, by providing the pressure regulating branch road and providing the second compressor on the hydrogen supply branch road, the low-pressure hydrogen produced by the external hydrogen supply device or the on-site hydrogen production device is first passed into the second compressor for pressurization and then passed into the first compressor for pressurization, so as to reduce the compression ratio of the first compressor during pressurization, avoid excessive compression ratio of the compressor causing excessive load on the compressor, and ensure stable and efficient operation of the hydrogen refueling station.