33results about How to "Reduce front and rear pressure difference" patented technology

The invention discloses a multiple on-line system and a mode switching control method thereof. The method includes the following steps that when any of a plurality of indoor units receives a mode switching instruction, the indoor unit sends the mode switching instruction to a flow distribution device; when judging that the indoor unit is switched into a heating mode from a refrigerating mode according to the mode switching instruction, the flow distribution device controls a refrigerating control valve corresponding to the indoor unit to be closed, and before controlling a heating control valve corresponding to the indoor unit to be opened, the flow distribution device adjusts the opening degree of a first throttling element so that the front and back pressure difference of the heating control valve corresponding to the indoor unit can be reduced. According to the method, when the indoor unit is switched into the heating mode from the refrigerating mode, the front and back pressure difference of the heating control valve is reduced by adjusting the opening degree of the first throttling element in the flow distribution device, and therefore noise generated during mode switching is lowered, and user experience is improved.

The invention provides a compression-absorption-diffusion composite refrigeration device and a refrigeration circulation method which adopts the device, while the device and the method belong to the technical field of refrigeration devices. The device is coupled in a series connected way by an absorption refrigeration system, a compression refrigeration system and a diffusion refrigeration system and is composed of a common heat exchange device, a throttling device and a refrigeration working medium; and the device comprises a liquid storage device, a solution pump, a generator, a rectifier, a first-stage condenser, a second-stage condenser, a compressor, a throttle valve, an evaporator and an absorber. Ammonia vapor completes first pressure increase in the diffusion refrigeration system and the absorption refrigeration system and enters the compressor through a pipeline after entering the first-stage condenser for completing second pressure increase, after that, the ammonia vapor enters the second-stage condenser to be cooled to liquid ammonia, the liquid ammonia enters the evaporator through the throttle valve, the evaporation and the refrigeration are carried out under the role of a diffusing agent of the evaporator, the liquid ammonia is further mixed with the diffusing agent to enter the absorber, ammonia in the absorber is absorbed, and the diffusing agent is returned back to the evaporator along the pipeline. The device of the invention is applicable to small-scale low-grade waste heat refrigeration occasions.

The invention provides a multi-cylinder two-stage variable-capacity compressor system. The multi-cylinder two-stage variable-capacity compressor system comprises a compressor in which a plurality of sets of rotating type compression mechanism parts are contained, wherein the compression mechanism parts comprise at least one high-pressure-stage rotating type compression mechanism part and at least two low-pressure-stage rotating type compression mechanism parts; one compression mechanism part in the low-pressure-stage compression mechanism parts is provided with a variable-capacity switching mechanism and further comprises an intermediate communicating pipeline introducing air suction pressure or intermediate pressure of the compressor to the variable-capacity switching mechanism. Air suction pressure or intermediate pressure is introduced to the variable-capacity mechanism by the multi-cylinder two-stage variable-capacity compressor so that the running modes of the variable-capacity compressor can be changed, the front and back pressure difference (between the head and the tail of a pin nail) of the variable-capacity mechanism is reduced, leakage loss caused by pressure difference is reduced, and the running efficiency of the compressor can be improved. The invention further relates to a control method of switching of running modes of the multi-cylinder two-stage variable-capacity compressor system.

The invention discloses a multi-split system and a switching control method of an operating mode of indoor units thereof. The switching control method comprises the following steps that when any of the multiple indoor units receives a mode switching instruction, the indoor unit sends the mode switching instruction to a flow dividing device; and the flow dividing device conducts switching control over a heating control valve or a refrigerating control valve corresponding to the indoor unit according to the received mode switching instruction, releases pressure by controlling a second throttling assembly, a first control valve and a bypass valve so as to decrease the front-back pressure difference of the refrigerating control valve or the heating control valve corresponding to the indoor unit, obtains the switching flag bit of a four-way valve, and controls the refrigerating control valve or the heating control valve and the four-way valve corresponding to the indoor unit according to the switching flag bit of the four-way valve, hidden pipeline cracking dangers caused by impact of coolants are better avoided accordingly, corresponding coolant impact noise is reduced, and the reliability of the system and the noise quality are improved.

The invention discloses an improved multifunctional butterfly plate based on an electric planer type shaft structure and a butterfly valve formed by the improved multifunctional butterfly plate. The two sides of the butterfly plate are respectively provided with an arch spherical protrusion, the arch spherical protrusion, on one side with a fluid inlet, of the butterfly plate is provided with three flow dividing channels used for flow division and pressure reduction, and the arch spherical protrusion, on one side with a fluid outlet, of the butterfly plate is provided with four flow dividing channels used for flow division and pressure reduction and provided with an installation hole part used for installing the butterfly plate in the radial direction. The multifunctional butterfly plate is improved based on a structure of a traditional butterfly plate of a standard flange type soft seal butterfly valve, high flowing speed of fluid passing through the butterfly plate can be reduced, the flow dividing channels can have the functions of flow division, pressure reduction, cavitation prevention, vibration prevention and noise reduction, and moreover when the butterfly valve is closed, the seal performance of a valve body can be improved.

The invention provides a combined valve. The combined valve can be free of leakage for a long time under severe working conditions. The combined valve comprises a combined valve body, wherein a medium inlet and a ball valve cavity communicated with the medium inlet are formed in one side of the combined valve body, a medium outlet and a stop valve cavity communicated with the medium outlet are formed in the other side of the combined valve body, the ball valve cavity is communicated with the stop valve cavity, a stop valve element arranged in the stop valve cavity a is connected with stop valve rod, a handle is connected to one end of the stop valve rod, a ball valve ball body arranged in the ball valve cavity is connected with a ball valve rod, the ball valve rod is connected with an output shaft at one end of a speed reduction mechanism, the other end of the speed reduction mechanism is connected with a driving gear for driving the speed reduction mechanism to rotate, the driving gear is meshed with a transition gear, and the stop valve rod drives the transition gear to rotate. The combined valve is integrally designed, has few leakage points, and is more reliable in pipeline installation, and more convenient to operate.

The invention discloses an auxiliary piston method for sealing an oil cylinder. The end of a guide sleeve of the oil cylinder, which is adjacent to the front chamber of the oil cylinder, is provided with a floating seal by installation, an external cylinder body and an external piston are installed on the external cylndrical surface of an oil cylinder barrel of the oil cylinder, the external piston can make reciprocating motion in certain distances along an axial direction in the external cylinder body, one end of the external cylinder body is provided with an oil pipe communicated with an oil groove by an oil passage, and the other end of the external cylinder body is provided with an oil pipe communicated with the rear chamber of the oil cylinder. A front and a rear piston rings are respectively installed on both ends of the piston, an internal cylinder body is processed in the axle center of the piston rod which is adjacent to the end of the rear chamber of the oil cylinder, an inner piston ring is installed in the internal cylinder body and can make reciprocating motion in certain distances along an axial direction in the internal cylinder body, and both ends of the internal cylinder body are provided with oil passages respectively communicated with the two oil grooves. The auxiliary piston method for sealing the oil cylinder enables the front and rear pressure differential of each soft seal ring to be far lower than the traditional oil cylinder by the displacement of an internal piston and an external piston during the motion of the oil cylinder, thereby slowing down the abrasion of each soft seal ring and prolonging the service life of the oil cylinder.

The invention discloses a self-adjustable pipeline rectifying device. A front rectifying body (2) and a rear rectifying body (7) are mounted in a rectifying device barrel (1) in the medium flowing direction from front to back. Front guide plates (3) evenly arranged in the circumferential direction of the front rectifying body (2) are welded to the inner wall of the rectifying device barrel (1) and the outer wall face of the front rectifying body (2), and the front rectifying body (2) is fixed in the rectifying device barrel (1). A guide ring (4) is mounted behind the front guide plates (3). The rear rectifying body (7) is mounted in the downstream direction of the guide ring (4). Rear guide plates (6) evenly arranged in the circumferential direction of the rear rectifying body (7) are welded to the inner wall of the rectifying device barrel (1) and the outer wall face of the rear rectifying body (7), and the rear rectifying body (7) is fixed in the rectifying device barrel (1). A self-adjusting guide cover (5) is mounted on the rear rectifying body (7). A fixed supporting frame (8) is mounted in the rear rectifying body (7). A sliding supporting frame (10) is mounted in the self-adjusting guide cover (5).

The invention provides a multi-cylinder two-stage variable-capacity compressor system. The multi-cylinder two-stage variable-capacity compressor system comprises a compressor in which a plurality of sets of rotating type compression mechanism parts are contained, wherein the compression mechanism parts comprise at least one high-pressure-stage rotating type compression mechanism part and at least two low-pressure-stage rotating type compression mechanism parts; one compression mechanism part in the low-pressure-stage compression mechanism parts is provided with a variable-capacity switching mechanism and further comprises an intermediate communicating pipeline introducing air suction pressure or intermediate pressure of the compressor to the variable-capacity switching mechanism. Air suction pressure or intermediate pressure is introduced to the variable-capacity mechanism by the multi-cylinder two-stage variable-capacity compressor so that the running modes of the variable-capacity compressor can be changed, the front and back pressure difference (between the head and the tail of a pin nail) of the variable-capacity mechanism is reduced, leakage loss caused by pressure difference is reduced, and the running efficiency of the compressor can be improved. The invention further relates to a control method of switching of running modes of the multi-cylinder two-stage variable-capacity compressor system.

The invention relates to an active balance pressure jet refrigeration system, which belongs to the technical field of energy and refrigeration. The active balance pressure jet refrigeration system is characterized in that based on the conventional jet refrigeration system, two heat exchangers are increased; refrigerant liquid is preheated by a first heat exchanger 18 or a second heat exchanger 29 and then enters a generator 14 so as to prepare working steam; a steam outlet end of the generator 14 is connected with a working steam inlet end of an ejector 1 by a pipeline; hot water enters the generator 14 by a pipeline and then respectively enters the heat exchanger 18 and the heat exchanger 29; the refrigerant liquid in the heat exchanger 18 and the heat exchanger 29 enters the generator 14 by pipelines; and cooling water of a condenser 2 enters the heat exchanger 18 or the heat exchanger 29 by pipelines. The active balance pressure jet refrigeration system of the invention has the advantages of sufficiently recycling solar energy or waste heat of factory production, reducing pre-and-post pressure difference of a liquid pump, improving the working efficiency of the pump and further strengthening the stability of the system operation.

The invention discloses a drainage water quality energy recovery system for thermal equipment and pipelines of a thermal power plant. The drainage water quality energy recovery system for thermal equipment and pipelines of the thermal power plant comprises a turbine low-pressure steam extraction regenerative system and a heat engine drainage system, the low-pressure steam extraction regenerative system is connected with the heat engine drainage system, a low-pressure heater drainage pump regenerative system comprises a low-pressure heater drainage pump pipeline, and a drainage pump and a secondary last-stage low-pressure heater are arranged on the low-pressure heater drainage pump pipeline. The drainage pump is connected in series with the secondary last-stage low-pressure heater to form adrainage pump branch; the heat engine drainage system comprises a drainage flash tank and a condenser. The steam space of the drainage flash tank is connected with the steam space of the condenser through a first steam exhaust pipeline. The water space of the drainage flash tank is connected with a condenser hot well through a first drainage pipeline; the steam space of the drainage flash tank isconnected with the secondary last-stage low-pressure heater through a second steam exhaust pipeline; and the water space of the drainage flash tank is connected with an inlet pipeline of the drainagepump through a second drainage pipeline. Drainage water can be recycled to a condensation water system, the heat load of a condenser is reduced, and the back pressure behind a thermal drain valve ofa power plant is improved.

The invention discloses a filtering process and a filtering system for use in preparation of an injection liquid medicament. The filtering process comprises the following steps of: preparing an injection in a preparation container (1), circulating by using a liquid medicament pump (2), filtering through a group of polypropylene filter cores (3), and reflowing a filtered solution into the preparation container (1) through a small circulating pipeline (8); and filtering by connecting the same group of polypropylene filter cores (3) with two groups of polyether sulfone filter cores (4, 7), forming a discharge port on a large circulating pipeline (5) behind the two groups of polyether sulfone filter cores, connecting the discharge port with the preparation container (1), and supplying a liquid medicament through another large circulating pipeline to perform production and quality detection of an injection. Through large and small circulations, impurities, heat sources, pigments and the like in the liquid medicament are removed effectively, and the aim of refining the liquid medicament is fulfilled; the filtering loads of the polypropylene filter cores and the pressure difference between moments before and after steam sterilization are lowered; and the use of active carbon in the conventional process is reduced, the requirement of environmental protection is better met, the possibility of adsorption of major components by active carbon is avoided simultaneously, and the quality of the liquid medicament is ensured.

The invention relates to a synchronous valve block of a bucket wheel machine tail. The synchronous valve block mainly comprises four throttle valves and a balance valve. By setting the balance valve at an outlet of the throttle valve, enough back pressure is established at the outlet, the flow regulation gain of the throttle valve is reduced, the regulation precision is improved, the synchronous precision of double cylinders of the tail is improved by 50%, the problem that the bucket wheel machine tail is asynchronous is well solved, and the safety and reliability of the tail for ascending and descending can be greatly improved.

The invention discloses a porous plate. The porous plate comprises a plate body, the plate body is provided with a plurality of air holes penetrating in the thickness direction of the plate body, each air hole comprises an air inlet section and an air outlet section which are sequentially arranged in the air flow direction, and the diameter of the air outlet section in the airflow direction is gradually increased. In the device operation process, airflow enters into the air inlet sections from the air inlet ends of the air holes and then enters into the air supply sections, and as the air supply section is in the variable-diameter tapered structure, the dynamic pressure of the air flow on the air outlet ends of the air holes is effectively reduced, thus the difference between the front pressure and the back pressure of the porous plate is correspondingly reduced, and meanwhile the air supply resistance is effectively reduced, the air supply efficiency is improved, and the comfort of the air supply process is correspondingly improved. The invention further discloses an air supply device applying the porous plate.

The invention discloses a protective valve, a compressor and an air conditioner. The compressor comprises a compression cylinder, a liquid storage tank and a pressure valve. An air cylinder and an exhaust cavity communicating with an air outlet of the air cylinder are arranged in the compression cylinder. The liquid storage tank communicates with an air inlet of the air cylinder. One end of the pressure valve communicates with the exhaust cavity, and the other end of the pressure valve communicates with the liquid storage tank. The pressure valve is in an open state when the pressure of the exhaust cavity is lower than a preset threshold value and is in a closed state when the pressure of the exhaust cavity is higher than the preset threshold value. According to the compressor, the pressure valve is arranged in a refrigerant circuit, when refrigerants are injected into the compressor, the pressure valve is in the open state since the pressure of the exhaust cavity is lower than the preset threshold value, part of the refrigerants can enter the liquid storage tank through the pressure valve, the front-back pressure difference of the air cylinder before the compressor is started is small, and the compressor protection effect is achieved.

The invention provides a power station waste heat recycling device and an energy saving system. A steam and water separator, a high voltage waste heat recycling unit, a low voltage waste heat recycling unit, a waste heat recycling water tank, a gas-liquid two phase steam trap and a waste heat recycling mother pipe are included; a steam inlet of the high voltage waste heat recycling unit communicates with the steam and water separator and corresponds to the upper end of a waste heat communicating pipe; a steam condensate water outlet of the high voltage waste heat recycling unit is connected tothe gas-liquid two phase steam trap, and then is combined with a high pressure softened water outlet of the high voltage waste heat recycling unit and connected to the waste heat recycling water tank; a steam inlet of the low voltage waste heat recycling unit communicates with the steam and water separator and corresponds to the lower end of the waste heat communicating pipe; a low pressure softened water outlet of the low voltage waste heat recycling unit is combined with the steam condensate water outlet and connected to the waste heat recycling water tank; and a water outlet of the waste heat recycling water tank is connected with the waste heat recycling mother pipe. The power station waste heat recycling device and the energy saving system have the advantages of being scientific in design, full in waste heat recycling, safe and stable, convenient to transform, and good in energy-saving effect.

The invention discloses a two-stage adjusting system suitable for an intermediate adjusting valve to participate in adjusting and lifting industrial steam supply parameters. A boiler reheating steam pipeline is divided into two paths after passing through an adjusting butterfly valve, wherein one path communicates with a first inlet of an intermediate-pressure cylinder through a first intermediate-pressure main steam valve and a first intermediate-pressure adjusting valve; and the other path communicates with a second inlet of the intermediate-pressure cylinder through a second intermediate-pressure main steam valve and a second intermediate-pressure adjusting valve. A boiler main steam pipeline communicates with an inlet of a high-pressure cylinder, a steam exhaust port of the high-pressure cylinder communicates with a cold recycling pipeline, and a steam extraction port of the high-pressure cylinder communicates with a steam extraction pipeline. The system can effectively solve the problems of vibration and sudden closing of the intermediate-pressure valve.

The invention provides a water supply recirculation valve protection system which comprises an electric stop valve, a pressure reduction assembly, a water supply recirculation valve and a manual stop valve which are sequentially arranged on a water supply recirculation pipeline, a controller, and a pressure measurement device which is arranged on a deaerator water tank and is used for measuring the pressure value of the water tank, the electric stop valve is located on the side, close to the water feeding pump, of the water feeding recirculation pipeline, the pressure reduction assembly is arranged, the upstream pressure of the water feeding recirculation valve can be reduced through the pressure reduction assembly, and therefore the washing degree is reduced, the service life is prolonged, the overhaul and maintenance frequency is reduced, leakproofness is ensured, and the leakage rate is reduced; the controller is electrically connected with the adjustable pressure reducing valve and the pressure measuring device, and the pressure reducing proportion of the adjustable pressure reducing valve can be controlled in real time according to the pressure value of the water tank, so that the front-back pressure difference of the water supply recirculation valve is reduced to the maximum extent while the recirculation water power is guaranteed, and the economical efficiency and safety of a unit during operation are remarkably improved.

The invention discloses a novel magnetic control butterfly valve. An electromagnetic controller is mounted on a valve body; an electromagnet is arranged inside the electromagnetic controller; a butterfly plate provided with a permanent magnet is mounted in an inner chamber of the valve body; an upper valve cover and a lower valve cover are fixed at the upper and lower ends of the valve body by boltsrespectively; the permanent magnet is fixed at the middle part of one end face of the butterfly plate; an upper shaft sleeve and a lower shaft sleeve which are coaxial to each other are fixed at the upper and lower parts of the end face, where the permanent magnet is positioned, of the butterfly platerespectively; the upper shaft sleeve and the lower shaft sleeve are matched and connected with the upper valve cover and the lower valve coverrespectively by an upper valve rod and a lower valve rod so that the butterfly plate can be mounted between the upper valve cover and the lower valve cover inside the valve body to form limited rotation; the other end face of the butterfly plate is provided with one inlet flow path and two outlet flow paths. The novel magnetic control butterfly valve disclosed by the invention is driven to rotate by rotation of the electromagnet inside the electromagnetic controller, so that the butterfly valve is controlled tobe opened and closed; the control theory of the butterfly valve is changed; flow division and decompression are carried out to reduce cavitation corrosion; vibration is prevented; noise is reduced; leakage problems of the butterfly valve are reduced; the working performance of the butterfly valve is improved; the butterfly valve is applicable to various occasions.

The invention discloses a gate valve with a function of reducing cavitation damage of a valve plate. The gate valve comprises a drive mechanism, a valve rod, a support, a valve cover, a valve body, gate plates, a sealing face, a coupler and a wedge block. A drive mechanism rotary shaft drives two gate plates in the valve cover and the valve body to vertical move through the coupler and the valve rod, the inner lateral face of the valve body is welded with the sealing face, and the wedge block and the valve rod are coaxially installed on the lower bottom surface of the valve body. The gate valve is characterized in that the lateral faces of the lower portions of the gate plates are provided with inner comb teeth and outer comb teeth, the front inner comb teeth, the front outer comb teeth, the back inner comb teeth and the back outer comb teeth are distributed in a staggered mode, and the thickness of the inner comb teeth is twice of that of the outer inner comb teeth. The gate valve is provided with the two gate plates, the gate plates are contacted with the sealing face when the valve is closed and opened, and good sealing performance of the sealing face and the gate plates is achieved through tensile force of the wedge block. In addition, the opening degree is small, fluid plays the flow-shunting and pressure-reducing effect and reduces front and back pressure drop of the gate plates when passes through the comb teeth on the gate plates, and a cavitation phenomenon of the valve is decreased.

The invention discloses a protective valve, a compressor and an air conditioner. The compressor comprises a compression cylinder, a liquid storage tank and a pressure valve. An air cylinder and an exhaust cavity communicating with an air outlet of the air cylinder are arranged in the compression cylinder. The liquid storage tank communicates with an air inlet of the air cylinder. One end of the pressure valve communicates with the exhaust cavity, and the other end of the pressure valve communicates with the liquid storage tank. The pressure valve is in an open state when the pressure of the exhaust cavity is lower than a preset threshold value and is in a closed state when the pressure of the exhaust cavity is higher than the preset threshold value. According to the compressor, the pressure valve is arranged in a refrigerant circuit, when refrigerants are injected into the compressor, the pressure valve is in the open state since the pressure of the exhaust cavity is lower than the preset threshold value, part of the refrigerants can enter the liquid storage tank through the pressure valve, the front-back pressure difference of the air cylinder before the compressor is started is small, and the compressor protection effect is achieved.

The invention discloses a maintenance-free high-pressure-difference gas-phase medium valve system. The system comprises a high-pressure-difference valve, a Laval pipe and a shrinkage pipe and is characterized in that the Laval pipe is fixedly installed at one end of the high-pressure-difference valve, the shrinkage pipe is fixedly installed at the end, away from the high-pressure-difference valve, of the Laval pipe, the high-pressure-difference valve is a gas-phase medium drainage emptying valve and is a gas-phase medium valve, the gas-phase medium valve is particularly a high-pressure-difference valve with the drainage emptying function, the Laval pipe is composed of a Laval inlet section, a Laval shrinkage section, a Laval balance section, a Laval diffusion section and a Laval outlet section, and the shrinkage pipe is composed of a shrinkage pipe inlet section, a shrinkage pipe shrinkage section and a shrinkage pipe outlet section. The maintenance-free high-pressure-difference gas-phase medium valve system is simple and practical, the maintenance period is shortened, the cost is reduced, and stable operation of a power plant is guaranteed.

The invention relates to an active balance pressure jet refrigeration system, which belongs to the technical field of energy and refrigeration. The active balance pressure jet refrigeration system is characterized in that based on the conventional jet refrigeration system, two heat exchangers are increased; refrigerant liquid is preheated by a first heat exchanger 18 or a second heat exchanger 29and then enters a generator 14 so as to prepare working steam; a steam outlet end of the generator 14 is connected with a working steam inlet end of an ejector 1 by a pipeline; hot water enters the generator 14 by a pipeline and then respectively enters the heat exchanger 18 and the heat exchanger 29; the refrigerant liquid in the heat exchanger 18 and the heat exchanger 29 enters the generator 14 by pipelines; and cooling water of a condenser 2 enters the heat exchanger 18 or the heat exchanger 29 by pipelines. The active balance pressure jet refrigeration system of the invention has the advantages of sufficiently recycling solar energy or waste heat of factory production, reducing pre-and-post pressure difference of a liquid pump, improving the working efficiency of the pump and furtherstrengthening the stability of the system operation.

The invention discloses a porous plate, comprising a plate body, the plate body has a number of air holes penetrating along its thickness direction, the air holes include an air inlet section and an air outlet section arranged in sequence along the air flow direction, the air outlet section The segments gradually increase in diameter along the airflow direction. During the operation of the equipment, the air flow enters from the air inlet end of the air hole, and then enters the air supply section through the air inlet section. Since the air supply section has a structure of variable diameter and gradual expansion, the air flow pressure at the air outlet end of the air hole is effectively reduced, so that the perforated plate The pressure difference between the front and back of the air compressor is correspondingly reduced, and at the same time, the air supply resistance is effectively reduced, the air supply efficiency is improved, and the comfort of the air supply process is correspondingly improved. The invention also discloses an air supply device using the perforated plate.

The invention discloses a valve plate of a butterfly valve based on reduction of cavitation damage. A taper angle alpha of a rigid sealing surface is greater than 45 degrees and less than 60 degrees, an assembling hole at the middle of the valve plate is biased to a fluid inlet from a central position of the valve plate, the valve plate, which is close to one side of the fluid inlet, is a plate surface, and the other side is a guide taper surface, three groups of comb teeth, which are uniformly arranged in a radial direction at radiuses of R1, R2 and R3 and a ratio of R1 to R2 to R3 of 11: 19: 27, are arranged on the plate surface and the guide taper surface, each group of the comb teeth can be inclined to the central position, a slant angle omega is greater than 60 degrees and less than 66 degrees, the comb teeth are cones provided with arcs at the top, the cone angles are 5-7 degrees, and the comb teeth between the groups are staggered at an equal distance. The valve plate, provided by the invention, has a function of a single-eccentric center butterfly valve, when the valve is opened or closed, a rubber valve seat is irregularly gradually compacted by the periphery of the valve plate from each position so as to generate a magnitude of interference, a hermetical pressure is realized, and the good sealing property is realized. In addition, fluid flows through the comb teeth on the valve plate, so that the pressure difference of the front and the back of the valve is reduced, and the valve cavitation phenomenon is reduced.