38results about How to "Accurate pressure regulation" patented technology

The invention relates to a safety relief temperature controlled electric pressure cooker and a precious voltage controlling method thereof. The temperature controlled electrical pressure cooler comprises a cooker cover, an inner cooker, an outer cooker, an electric heating device and an electric control gear, wherein the cooker cover and the outer cooker can be connected in a detachably fastened mode; the inner cooker can be freely arranged in a cavity formed between the cooker cover and the outer cooker, and a sealing ring is arranged between the inner cooker and the cooker cover; and the cooker cover is provided with an upper temperature detector for detecting the temperature in the inner cooker, an elastic relief device is arranged between the bottom part of the inner cooker and the outer cooker, and the elastic relief device can sense the cooking pressure in the inner cooker so as to drive the inner cooker to move downwards and comprises an elastic member and a strut member for accommodating the elastic member. The precious temperature controlling method comprises a heating stage in which a master controller heats with small power so as to perform temperature compensation based on the temperature deviation deltaT and the reference temperature deltaTB. The invention can improve the temperature control property and voltage control precision of the temperature controlled electric pressure cooker.

The invention discloses a speed regulation control method of air conditioner outdoor fan. The method uses the temperature of conditioner outdoor coil pipe to reflect the system pressure. The RPM regulation and control strategy of the outdoor fan is designed base on the combinational factors of changes of the outdoor environmental temperature and the outdoor coil pipe temperature. Through the control of outdoor fan RPM the outdoor coil pipe temperature can be regulated. Through controlling the outdoor coil pipe temperature within the set range of temperature the system pressure can be stabilized within the scope of the reliable operation of the compressor, therefore the safe operation of the compressor can be guaranteed. Because the precise regulation of the PRM of the outdoor fan can be achieved without the unnecessary pressure sensor installation in the air conditioner system for collecting the system pressure, so the accruement of hardware cost of the product can be avoided. At the same time the stepless speed regulation is used in the outdoor fan to enhance the stability of the system pressure control, and improve the air conditioning system work performance. The method is especially useful for the base station air conditioner to enhance the system operation reliability of the base station air conditioner.

The invention discloses a method and a device for testing and evaluating tolerance of a drive motor system of a frequency converter under power supply disturbance. The method comprises steps as follows: 1, an instantaneous voltage disturbance resisting test; 2, a long-time voltage fluctuation test; 3, a harmonic disturbance test. The device comprises a power supply grid, a switch Q1, a switch Q2,a switch Q3, a power supply disturbance generator, a tested frequency converter, a tested electric motor, a pulled power generator, a filter device, a voltage compensator, a storage battery, a measurement control unit, a base, a rotating shaft, a UPS (uninterrupted power supply) and a grid-connected frequency converter. The device has the advantages that the device has accurate voltage regulationand frequency modulation and high fault simulation capability and can realize the functions of energy feedback, coordination control of rotating speeds and torque, high-speed and high-accuracy acquisition of the electric quantity and the mechanical quantity, measurement of temperature rising of a motor winding, control of software and machine starting and stopping, torque control, real-time display, wave recording, switch control as well as data analysis and computation.

The invention belongs to an experiment device for gas monitoring in a coal mine and particularly relates to a coal and gas outburst jet characteristic simulation experiment device. The upper end of a sleeve (1) is in threaded connection with an upper end cover (2), and the lower end of the sleeve (1) is in threaded connection with a lower end cover (3); a lower pressing plate (7) is installed between the inside of the sleeve (1) and the lower end cover (3); a lower positioning plate (9) is installed between the lower pressing plate (7) and the sleeve (1); a solid pressure measuring plate (10) is arranged on the lower positioning plate (9); an oil cylinder (13) is embedded on the solid pressure measuring plate (10); a hollow side pressing plate (11) is arranged on the lower positioning plate (9) at the right side; upper positioning plates (8) are arranged on the hollow side pressing plate (11) and the solid pressure measuring plate (10); an upper pressing plate (6) is arranged above a coal sample (16); a baffle (5) is arranged above the sleeve (1); a piston rod (4-1) is arranged in a central hole of the baffle (5); and a piston (4) is arranged between the inside of the upper end cover (2) and the baffle (5). The coal and gas outburst jet characteristic simulation experiment device has the beneficial effects that the influence of passively opening an outburst port on outburst energy due to slow speed is avoided, the pressure is kept constant, and the required pressure can be accurately adjusted.

A multi-output two-stage DC / DC converter using a composite PCB board-type transformer, including a main circuit (1), and the main circuit includes cascaded pre-stage converters (3) and post-stage converters (4) ; After the pre-stage converter (3) protects the busbar voltage through the surge current suppression circuit (5) and filters the EMI input filter circuit (6), the busbar voltage is reduced by the push-pull circuit (7) and the transformer isolation circuit (8). Transformed into N output voltages, each output voltage is respectively rectified and smoothed by the filter circuit (9) and then output to the rear-stage converter (4); the output secondary adjustment circuit in the rear-stage converter (4) receives the previous-stage The output smoothed and filtered voltage adjusts the input voltage according to the magnitude of the output current of each channel, and the adjusted voltage is output under the timing control of the output relays of each channel and the control loop (11). The invention overcomes the deficiencies of the prior art, can be applied to various spacecraft, and has many output channels and high reliability.

The invention discloses a testing method of a fluid-structure interaction analog simulation testing device. The testing method includes steps of firstly, filling a simulated stratum material in a simulated box body according to the lamellar distribution; filling water by a water filling device and simulating the water-containing layer; then horizontally pressurizing both sides of the simulation box body by a horizontal hydraulic loading system so as to simulate the confining pressure; at last, performing vertical pressure loading on the simulated box body by a vertical directional hydraulic loading system so as to simulate loads with different depths. The testing method of the fluid-structure interaction analog simulation testing device can be adapted to different experimental demands. The testing method can realize accurate pressure adjusting, simulate loads with different depths of the stratum, an apply uneven pressure.

The invention discloses a multifunctional intelligent power-saving device which is characterized by having voltage stabilizing and undervoltage outputting functions according to the lightening function of an underground parking garage; a transformer is shifted in a contactless mode so as to avoid the fluctuation of a commercial power supply; when people enter the underground parking garage, normal voltage is output by a sensing probe and all illuminating lamps are turned on; and for a moment after the people leave from the underground parking garage, standard undervoltage is output and part of illuminating lamps is turned off so as to achieve the aim of saving power. The dead hours of after midnight each day can also be set as a regular energy-saving time period; a user can set over-voltage, undervoltage and normal voltage parameters by using keys; and meanwhile, the over-voltage, undervoltage and normal voltage parameters can be displayed through a liquid crystal display screen or are remotely set and controlled through a GPRS (General Packet Radio Service) wireless network.

The invention relates to die-cutting equipment, in particular to an automatic pressure-regulating machine for a die-cutting machine. The automatic pressure-regulating device is applied to a platen die-cutting machine; one end of the front segment of a connecting rod is provided with a connecting rod hole matched with an eccentric segment; the other end of the front segment of the connecting rod is rotationally connected to the front end of the back segment of the connecting rod; a hollow stud is rotationally sleeved at the tail end of the back segment of the connecting rod. The device further comprises a worm reducer and a pressure-regulating nut, wherein a pressure-regulating motor is connected with a worm of the worm reducer; a guide hole is formed in the center of a worm wheel of the worm reducer; a guide shaft is inserted into the guide hole; an axial guide component is arranged between the guide shaft and the guide hole; one end of the guide shaft is fixedly connected with the tail end of the hollow stud; the pressure-regulating nut is fixedly connected with a following base; the hollow stud is screwed on the pressure-regulating nut. The automatic pressure-regulating device for the die-cutting machine is accurate in pressure regulation, and convenient to operate.

The invention discloses a high-voltage transformer with an accurately-controlled transformation ratio. The high-voltage transformer comprises a rotor shaft, a first speed reduction box, an electromagnetic clutch and a voltage acquisition device, wherein the rotor shaft is led out of an upper end of a transformer body, a rotor gear is arranged at the upper end of the rotor shaft, the first speed reduction box is arranged at the upper end of the transformer body, a motor is arranged on the first reduction box, an output shaft of the motor is connected with an input shaft of the first speed reduction box, the motor is connected with a controller of the transformer, the electromagnetic clutch is selectively connected with the rotor gear and an output shaft of the first speed reduction box and is connected with the controller, and the voltage acquisition device is arranged at the output end of the transformer and is connected with the controller. By the high-voltage transformer, the technical problem that the transformation ratio of an adjustable transformer cannot be accurately controlled is solved.

The invention relates to a high voltage regulating autotransformer and belongs to the technical field of transformer manufacturing. According to the technical scheme, a serial winding of the autotransformer is serially connected with a voltage regulator. The voltage regulator comprises an iron core, a voltage regulator serial winding (6) and a voltage regulator excitation winding (7). The voltage regulator serial winding is serially connected with the serial winding (4) of the autotransformer. The voltage regulator excitation winding is connected with a power supply winding (2) of the autotransformer. A tapping regulating device of the voltage regulator is connected with the power supply winding of the autotransformer or the voltage regulator excitation winding. By regulating winding number of the power supply winding of the autotransformer, the voltage regulator excitation winding and the voltage regulator serial winding, voltage of the voltage regulator serial winding can be regulated freely during different tapping, and accordingly the voltage of the serial winding of the autotransformer is regulated, and precise high voltage regulation of the autotransformer is realized. The high voltage regulating autotransformer has the advantages that precise high voltage regulation of the autotransformer is realized.

The invention relates to the die-cutting machining technology, in particular to an automatic pressure regulating device of a die-cutting machine. A pressure regulating assembly is arranged between an upper die holder and an upper die base of the die-cutting machine, and the pressure regulating assembly comprises a lead screw and a nut; the nut is fixedly connected to the upper die holder, the lead screw is connected with a worm wheel arranged on the upper die base, the upper die base is further provided with a pressure regulating motor, the pressure regulating motor is meshed with the worm wheel through a worm, a rack is installed on the upper die holder through a guide device, the upper die holder is provided with a locking air cylinder, a piston rod of the locking air cylinder is connected with the rack, the lead screw is further provided with an auxiliary nut; the auxiliary nut is located above the nut, a gear is arranged on the outer wall of the auxiliary nut; the gear is meshed with the rack. The automatic pressure regulating device of the die-cutting machine can accurately regulate pressure and does not loosen.

The invention discloses a large-load low-frequency air bag vibration isolator for a ship, which comprises a fixed base and a mounting bottom plate, a limiting box is mounted on the top face of the fixed base, a first vibration isolation air bag is mounted in an inner cavity of the limiting box, the mounting bottom plate is connected to the top end of the first vibration isolation air bag, and a plurality of piston cylinders are symmetrically mounted on the top face of the fixed base; a pressure adjusting piston is installed in an inner cavity of each piston cylinder, the top end of each pressure adjusting piston is connected with a pressure adjusting plate, fixing plates are symmetrically installed on the top faces of the side faces of the two sides of the limiting box, nuts are installed in the centers of the fixing plates, pressure adjusting threaded rods are engaged with the interiors of the nuts, and the bottom ends of the pressure adjusting threaded rods are installed in the centers of the top faces of the pressure adjusting plates through connecting bases; and the inner cavities of the piston cylinders communicate with an inner cavity of the first vibration isolation air bag through first communicating pipes. The large-load low-frequency air bag vibration isolator has the advantages that on the premise that external tools are not used, a user can conveniently and rapidly adjust the air pressure in the air bag, and therefore convenience is brought to air bag air pressure adjustment of the large-load low-frequency air bag vibration isolator for the ship.

The invention relates to a die cutting device, in particular to a flat-press type pressure adjusting device of a die cutting machine and a method thereof. The pressure adjusting device of a die cutting machine comprises a connecting bar connected between a crank and a slide block; the connecting bar comprises two sections; the two sections of connecting bars are integrally docked with each other through a nut / screw rod structure; the device can adjust the pressure of the die cutting machine by adjusting the fastening length of the screw rod; the pressure adjusting method of a die cutting machine comprises the following steps: adjusting the height of a step by grinding a sub nut to eliminate an axial clearance between a main nut and the sub nut as a whole body and the screw rod. The invention provides a pressure adjusting device of a die cutting machine and a method thereof with accurate pressure adjustment.

A manual and precision plunger pressurizing pump comprises a plunger pressurizing structure, a mechanical drive structure and a frame, wherein the frame comprises a baseplate, a front support upright plate and a rear support upright plate; the plunger pressurizing structure comprises an outer cylinder body, a plunger guide sleeve, a plunger and a cylinder body end cover; the plunger guide sleeve is mounted inside the outer cylinder body; the plunger is mounted in the plunger guide sleeve in a sleeving manner, and moves frontward and backward along an inner hole of the plunger guide sleeve; the mechanical drive structure comprises a trapezoid screw rod mechanism, a planetary gear retarding mechanism and a guide rail structure; the guide rail structure comprises a guide rail pull rod, a guide sleeve, screw rod nut fixing plates and a plunger driving sleeve; the trapezoid screw rod mechanism comprises a trapezoid screw rod shaft and a screw rod nut; the screw rod nut is in meshed transmission with the trapezoid screw rod; the planetary gear retarding mechanism comprises a sun gear, a planet gear, an outer gear ring and a planet wheel carrier. The manual and precision plunger pressurizing pump provided by the invention can realize precision pressure regulation under middle / low pressure especially high pressure, and the pressure regulation process is stable without fluctuation.

The invention relates to a low-voltage regulating transformer and belongs to the technical field of manufacture of transformers. According to the technical scheme, a voltage regulator is serially connected to a low-voltage winding of a power transformer and comprises two windings and a regulator core, one winding is a series winding (6) serially connected with a low-voltage winding (3) of the transformer, the other winding is an exciting winding (7) connected with a power supply winding (2), and the power supply winding (2) in the transformer is used to power the regulator. A tap regulating device of the regulator is connected with the exciting winding of the regulator, or connected with the power supply winding, which is inside the regulator and powers the regulator. Voltage of the series winding (6) in different tapping modes is optionally changed by adjusting the number of turns of the power supply winding (2), the exciting winding (7) and the series winding (6), so that voltage of the low-voltage winding is regulated accurately. The low-voltage regulating transformer has the advantage that the voltage of the low voltage winding of the low-voltage regulating transformer can be regulated accurately.

The invention discloses a bottled liquefied petroleum gas pressure regulator with a flameout protection function. The bottled liquefied petroleum gas pressure regulator comprises a pressure regulatorbody, a furnace head and an electric control system, wherein the pressure regulator body comprises a valve body, a valve cover arranged on the valve body, a gas inlet channel arranged on one side of the valve body and a gas outlet channel arranged on the other side of the valve body, the pressure regulator body communicates with the furnace head through the gas outlet channel, and a pressure regulating device is arranged in the valve body; and a protective shell and a protective cover are arranged on the valve cover, a supporting plate is arranged in the protective shell, an electromagnet is arranged on the supporting plate, the pressure regulating device is controlled by the electromagnet, and a thermocouple is arranged on the furnace head. The bottled liquefied petroleum gas pressure regulator has the beneficial effects that the functions of the pressure regulator and a flameout protection device are combined, and the efficient and safe utilization of the gas can be fully ensured; and the electromagnet is arranged on the pressure regulator body, the pressure regulator body can be shut off in case of accident flameout, and the gas path is cut off.

The invention relates to a power supply of a neon lamp and specifically relates to a neon-lamp power supply which is adjustable in voltage. The power supply for the neon lamp includes an AC power supply, a high-frequency electronic transformer and a rectifying circuit. The AC power supply is connected with the high-frequency electronic transformer. The rectifying circuit is connected to an output end of the high-frequency electronic transformer. An output end of the rectifying circuit is connected with the neon lamp. A voltage adjustment circuit is connected between the rectifying circuit and the high-frequency electronic transformer. After the structure is adopted, the power supply of the neon lamp is capable of adjusting the voltage accurately so that the neon lamp works in a best state.

The invention provides a pressure control device and a pressure increasing and decreasing control method. The pressure control device comprises a power assembly, a transmission assembly and a pressureregulating valve connected in sequence, wherein under the condition that a bidirectional clutch in the transmission assembly is in a first transmission state, when the power assembly moves in the first direction, the bidirectional clutch is engaged to drive the pressure regulating valve to carry out pressurization action, and when the power assembly is reversely reset in the second direction, thebidirectional clutch is separated; under the condition that the bidirectional clutch is in a second transmission state, when the power assembly moves in the second direction, the bidirectional clutchis engaged to drive the pressure regulating valve to perform pressure reduction action, and when the power assembly is reversely reset in the first direction, the bidirectional clutch is separated. By the adoption of the bidirectional clutch, the process of increasing and reducing the pressure of a hydraulic system is realized, the structural assemblies are simplified, and the equipment utilization rate is high; and the pressure control device has the advantages that pressure regulating operation is simple and convenient, occupied mounting space is small, the structural cost is low and energyconsumption is low.

The invention relates to a safety relief temperature controlled electric pressure cooker and a precious voltage controlling method thereof. The temperature controlled electrical pressure cooler comprises a cooker cover, an inner cooker, an outer cooker, an electric heating device and an electric control gear, wherein the cooker cover and the outer cooker can be connected in a detachably fastened mode; the inner cooker can be freely arranged in a cavity formed between the cooker cover and the outer cooker, and a sealing ring is arranged between the inner cooker and the cooker cover; and the cooker cover is provided with an upper temperature detector for detecting the temperature in the inner cooker, an elastic relief device is arranged between the bottom part of the inner cooker and the outer cooker, and the elastic relief device can sense the cooking pressure in the inner cooker so as to drive the inner cooker to move downwards and comprises an elastic member and a strut member for accommodating the elastic member. The precious temperature controlling method comprises a heating stage in which a master controller heats with small power so as to perform temperature compensation based on the temperature deviation deltaT and the reference temperature deltaTB. The invention can improve the temperature control property and voltage control precision of the temperature controlled electric pressure cooker.

The invention discloses a charging circuit with dual output ports, which comprises a primary side conversion circuit, a secondary side first conversion circuit, a secondary side second conversion circuit, and a transformer connecting these three circuits; the output of the secondary side second conversion circuit is sampled The voltage and output current are compared and compensated with the reference value to finally control the on-off time of the switch in the primary side conversion circuit; the output current of the primary side conversion circuit is sampled, and the zero-crossing delay is calculated through zero detection, and then the secondary side is controlled. Second, the on-off time of the rectifier switch in the conversion circuit; the invention also discloses the control method of the charging circuit; compared with the prior art, the invention can flexibly control two direct currents by using a DSP (digital signal processor). The voltage of the output port is precisely adjusted and has strong anti-interference ability; at the same time, it has the advantages of simple structure, convenient setting, small size, low cost and light weight.

The invention discloses a high-voltage transformer with an accurately-controlled transformation ratio. The high-voltage transformer comprises a rotor shaft, a first speed reduction box, an electromagnetic clutch and a voltage acquisition device, wherein the rotor shaft is led out of an upper end of a transformer body, a rotor gear is arranged at the upper end of the rotor shaft, the first speed reduction box is arranged at the upper end of the transformer body, a motor is arranged on the first reduction box, an output shaft of the motor is connected with an input shaft of the first speed reduction box, the motor is connected with a controller of the transformer, the electromagnetic clutch is selectively connected with the rotor gear and an output shaft of the first speed reduction box and is connected with the controller, and the voltage acquisition device is arranged at the output end of the transformer and is connected with the controller. By the high-voltage transformer, the technical problem that the transformation ratio of an adjustable transformer cannot be accurately controlled is solved.

The invention discloses a fluid-structure interaction analog simulation test device, which comprises a rack, a simulation box body, a vertical direction hydraulic loading system and a horizontal direction hydraulic loading system, wherein the rack comprises a base, an upright post, a cross beam and a guide rail; the base is glidingly arranged on the guide rail through the lower surface; the vertical direction hydraulic loading system comprises a first telescopic pressurization device and an upper pressurizing plate; the first telescopic pressurization device performs vertical pressure loading on the simulation box body through the upper pressurization plate; the horizontal direction hydraulic loading system comprises a second telescopic pressurization device, a pressure resistant plate and a lateral pressurization plate; the pressure resistant plate and the side pressurization plate are respectively arranged at the two ends of the second telescopic pressurization device; the second telescopic pressurization device performs the lateral pressure loading on the simulation box body through the butt joint with the simulation box body through the lateral pressurization plate. The test device has the advantages that the horizontal hydraulic loading is modularized; each module can realize the single pressure control; the precise pressure regulation is realized; the top vertical pressurization is controllable; different depth load of the stratum is simulated; non-uniform pressure can be exerted.

The invention relates to the technical field of electric vehicle charging control systems, in particular to a transformer-controlled double-path charging circuit. The circuit comprises an a-end conversion circuit, a b-end conversion circuit, a c-end conversion circuit and a transformer T for connecting the three circuits, the invention further discloses a control method of the transformer-controlled double-path charging circuit. The method comprises the following steps: S1, the controller compares the b-end output voltage and the b-end output current with given output values respectively; andobtaining a result value by inputting a result into a three-pole three-zero-point digital compensator network, wherein the value changes the switching period of an a-end power switch tube and is usedfor controlling the on-off of a first group of power switches Q1 and Q4 and a second group of power switches Q2 and Q3 respectively. The voltage of the two ports can be flexibly controlled by one transformer, the voltage regulation is accurate, and the anti-interference capability is strong; and meanwhile, the circuit has the advantages of small size, low cost and light weight.

The invention belongs to the field of voltage regulation of transformers, and discloses a single-phase autotransformer and a voltage regulation method. The transformer comprises a first side column, a second side column, a main column arranged between the first side column and the second side column, a first tap switch and a second tap switch, a low-voltage coil, a common coil, a series coil and a first voltage regulating coil are sequentially wound on the main column from inside to outside, and a second voltage regulating coil is wound on the first side column; the first tap switch adjusts the number of connected turns of the first voltage regulating coil, and the second tap switch adjusts the number of connected turns of the second voltage regulating coil. The first voltage regulation coil is arranged on the main column, the second voltage regulation coil is arranged on the first side column, the first voltage regulation coil and the second voltage regulation coil are matched and connected in series, and the voltage regulation precision is controlled by setting the turn ratio of the first voltage regulation coil to the second voltage regulation coil. According to the utility model, accurate voltage regulation can be realized, the cost is low, a large-capacity excitation coil does not need to be arranged, the copper consumption is reduced in the same voltage regulation range, and the cost is low.

The invention discloses a speed regulation control method of air conditioner outdoor fan. The method uses the temperature of conditioner outdoor coil pipe to reflect the system pressure. The RPM regulation and control strategy of the outdoor fan is designed base on the combinational factors of changes of the outdoor environmental temperature and the outdoor coil pipe temperature. Through the control of outdoor fan RPM the outdoor coil pipe temperature can be regulated. Through controlling the outdoor coil pipe temperature within the set range of temperature the system pressure can be stabilized within the scope of the reliable operation of the compressor, therefore the safe operation of the compressor can be guaranteed. Because the precise regulation of the PRM of the outdoor fan can be achieved without the unnecessary pressure sensor installation in the air conditioner system for collecting the system pressure, so the accruement of hardware cost of the product can be avoided. At the same time the stepless speed regulation is used in the outdoor fan to enhance the stability of the system pressure control, and improve the air conditioning system work performance. The method is especially useful for the base station air conditioner to enhance the system operation reliability of the base station air conditioner.

The invention discloses a neurosurgery interventional operation catheter device which comprises a working box, a support is fixed to the bottom of the working box, a base is fixed to the bottom of the support, a partition plate is fixed to the inner wall of the working box, and a first catheter and a second catheter are inserted into the upper end of the working box in a penetrating mode. The first guide pipe and the second guide pipe are jointly communicated with a drainage pipe, the end of the drainage pipe is connected with a speed control box, the bottom of the speed control box is connected with a drainage head, a flow speed regulation and control mechanism is arranged in the speed control box, and a pressure meter and a pressure sensor are arranged on the side wall of the working box. The drainage device has the advantages that drainage of the two areas in the working box is carried out alternately, accumulated liquid is discharged in time, continuous drainage operation can be achieved, the drainage efficiency is greatly improved, it is guaranteed that the drainage pressure of each time is the same, and therefore discomfort and even injury caused by changes of the drainage pressure to a patient are avoided; therefore, the drainage effect is improved.

The invention relates to a gear pump safety valve structure. The safety valve structure comprises a valve element and a valve sleeve, the valve element is of a rotation body structure, a work portionis arranged on the front portion of the valve element, the rear portion of the valve element is in a rod shape, the appearance of the front portion of the valve element is a combination of a round table and a round convex head, the outer diameter of the round convex head is smaller than the radius of the upper table board of the round table, the tail of the round convex head and the upper table board of the round table are in rounding arc transition, the head portion of the round convex head is in a hemispheric shape, the rear portion of the valve element is arranged in the valve sleeve, and is in sliding fit with the valve sleeve, the front portion of the valve element is located outside the valve sleeve, and the radius of a lower table board of the round table is larger than the inner diameter of the valve sleeve. Valve pressure adjusting is precise, the pressure relief is stable and rapid, and sensitivity and the reliability are high.