32 results about "NPSH" patented technology

The invention discloses a well submersible pump hydraulic design data modeling method, which comprises five steps of sensing acquisition, hydraulic data enhancement, hydraulic performance prediction, intelligent material matching and modeling output, relates to the technical field of pump hydraulic modeling analysis, and particularly relates to a well submersible pump hydraulic design data modeling method and system. A physical information confrontation generative network is combined with a space-time Kriging interpolation algorithm to enhance three-dimensional flow field data; a multi-modal graph neural network fusing physical control loss is constructed, and dynamic prediction of performance indexes such as pump body efficiency, lift and net positive suction head is achieved; based on a corrosion-wear coupling model and a reinforcement learning algorithm, the service life, the cost and the machinability of candidate materials are evaluated, an optimal combination is intelligently recommended, and systematic support is provided for design of an efficient, low-cost and long-service-life submersible pump for a well.

The invention discloses an inducer efficient anti-cavitation numerical optimization method based on blade reverse parameterization, and relates to the technical field of optimization design of inducers for pumps, the inducer is designed and machined through five-axis linkage numerical control, and meanwhile, an inducer visual cavitation test testbed is built; hydraulic performance and cavitation erosion tests are carried out through a test bed, and curves of lift, efficiency, net positive suction head and cavitation erosion area changing along with time are obtained; finding an inducer turbulence model, an inducer cavitation model and a cavitation erosion calculation model with the minimum calculation error; carrying out reverse parametric modeling on the inducer blade; building an inducer parameterized intelligent computing platform based on modeling; screening main geometric parameters of the inducer; optimizing the inducer based on the turbulence model, the cavitation model, the cavitation erosion model and the intelligent computing platform; and performing hydraulic performance test and cavitation erosion test verification on the optimized inducer. The anti-cavitation performance of the inducer can be effectively improved.

The invention provides a steam turbine generator unit feed pump net positive suction head detection system and method, relates to the technical field of net positive suction detection, and solves the technical problem that net positive suction is difficult to recognize in advance in the prior art. The system specifically comprises a temperature acquisition module used for acquiring the temperature of the deaerator; the judgment and early warning module is used for receiving the flow change rate of the feed pump and triggering alarm when the flow change rate exceeds a flow threshold value; the effective net positive suction head calculation module is used for converting the inlet pressure of the water feeding pump into absolute pressure; temperature correction is conducted on the temperature of the deaerator to obtain the saturation temperature of an inlet of the water feeding pump, the saturation temperature is converted into saturated vapor pressure, and the effective net positive suction head is calculated based on the absolute pressure and the saturated vapor pressure; the necessary net positive suction head obtaining module is used for calling the necessary net positive suction head table and calculating and obtaining the necessary net positive suction head; and the net positive suction head calculation module is used for receiving the effective net positive suction head and the necessary net positive suction head and calculating the net positive suction head. The device is used for detecting the net positive suction head.

The utility model discloses a high-pressure shield pump. Comprising a pump body, an impeller, a first companion flange, an outer circulation pipeline, a second companion flange, a fourth hole, a third hole, a rear bearing body, a second hole, a second bearing three-piece set, an auxiliary impeller, a second cavity, a rotor assembly, a motor gap, a stator isolation sleeve, a first cavity, a first bearing three-piece set, a front bearing body, a wear-resisting plate, an inducer and a first hole. According to the utility model, the inducer is arranged at the inlet of the pump to reduce the net positive suction head of the pump, so that inlet cavitation is prevented, and dual pressurization is realized by a method of improving the pressure of the circulating inlet and arranging the auxiliary impeller inside, so that medium gasification is prevented.

This application provides a high-cavitation-resistant pressure-reducing sludge pump, belonging to the field of centrifugal pump technology. Because the pump transports a high-temperature medium with a low inlet pressure, the medium at the pump inlet is in a critical saturation state. At this point, the medium is highly susceptible to vaporization, forming a large number of bubbles. The bursting of these bubbles generates impact, causing cavitation damage to the inlet blades of the first-stage impeller, resulting in pump vibration, noise, and a sudden drop in head, ultimately leading to pump damage. Increasing the pump inlet pressure and decreasing the medium temperature are not feasible. The only solution is to optimize the pump body. Since the inlet of the first-stage impeller is highly susceptible to cavitation, the first-stage impeller is designed with double suction to increase the pump's net positive suction head (NPSH), thereby reducing the possibility of cavitation in the first-stage impeller and ensuring more stable pump operation. Due to the high pump outlet pressure, the coordinated operation of the first and second-stage impellers can mitigate excessive pressure on individual impeller components, thus extending the pump's service life.

The invention discloses a method and a system for controlling the net positive suction head of a water feeding pump set of a thermal power plant, and belongs to the technical field of automatic control of thermal generator sets. The method comprises the following steps: determining an allowable pressure change lower limit of a deaerator by acquiring the actual available net positive suction head of an inlet of a water feeding pump; acquiring the time required for water in the deaerator to flow to the inlet of the water feeding pump; according to the lower pressure change limit and time of the deaerator, the condensed water flow increment for preventing insufficient net positive suction head of the water feeding pump is obtained; determining a condensed water flow limit value for preventing insufficient net positive suction head of the water feeding pump; when the actual condensed water flow is larger than the condensed water flow limiting value, the output of the deaerator liquid level automatic control module is limited to be increased; when the actual condensed water flow is smaller than the condensed water flow limit value or the condensed water flow increment is a negative number, the deaerator liquid level automatic control module works normally. According to the method, the insufficient net positive suction head of the water feeding pump set is prevented by limiting the flow of the condensed water in the accident state, and the safety and stability of thermal power plant operation are improved.

The invention discloses a cavitation heating method and system based on artificial intelligence. The method comprises the steps that sound data from an acoustic sensor and vibration data from a vibration sensor are obtained; acquiring other data from other sensors; performing time-frequency domain analysis on the sound data and the vibration data; associating the processed sound data, vibration data and other sensor data according to a time axis; training a machine learning model by using multiple groups of training data; and obtaining input data according to sensor data collected in real time and the net positive suction head NPSH value obtained through calculation, inputting the input data into the machine learning model, and outputting the current or future cavitation state of the cavitation heating device in the machine learning model. The problem that monitoring of a single parameter is not beneficial to inaccurate judgment of the cavitation heating operation state is solved, and therefore the accuracy of the operation state of the cavitation heating device is improved to a certain degree.

The present application relates to the technical field of boiler feed water pump cavitation control, and discloses a self-adaptive adjustment method and system for preventing cavitation of a boiler feed water pump, which acquires the inlet pressure, inlet water temperature and feed water flow of the pump in real time, calculates the effective net positive suction head NPSHa and looks up the required net positive suction head NPSHr, calculates the margin coefficient and makes a judgment, and drives the frequency converter and the inlet regulating valve to adjust in coordination according to the judgment result. The system comprises a parameter acquisition unit, a self-adaptive controller, an actuator and a man-machine interaction unit. The present application can effectively prevent cavitation from occurring and reduce the energy consumption of the feed water pump by real-time dynamic calculation and coordinated adjustment of the net positive suction head, and can adapt to the nonlinear pressure variation characteristics of sliding pressure operation, and balance the rapidity of cavitation protection and the economy of operation.

The utility model discloses a vertical low-cavitation single-stage centrifugal pump, belongs to the technical field of vertical single-stage centrifugal pumps, and particularly relates to a centrifugal pump with a vertical, single-stage and barrel-bag type structure. According to the vertical low-cavitation single-stage centrifugal pump, the energy difference value between the net positive suction head of the device and the necessary net positive suction head of the pump is increased, enough surplus is reserved, it is fully guaranteed that even under the extremely severe working condition or the potential hazard working condition, cavitation faults of the pump cannot be found, and the safety and reliability of long-term operation are improved. The pump comprises a power part with a pump shaft, a discharge shell is arranged below the power part, a pump cylinder is arranged below the discharge shell, and the lower end of the pump shaft penetrates through the discharge shell and is arranged in the pump cylinder. The pump is characterized in that a connecting pipe which is integrally communicated is arranged in the discharge shell and the pump cylinder, and the lower end of the connecting pipe is connected with a middle section; and the lower end of the pump shaft is connected with the impeller in the middle section and is provided with a suction inlet of the impeller.

The utility model discloses a vertical self-priming condensate pump, including pump body, impeller, pump shaft, pump shaft drive piece and pump chamber subassembly, the pump body is provided in the pump chamber subassembly, the impeller is installed at the lower end of the pump shaft and is located in the pump body, the pump shaft drive piece is connected with the upper end of the pump shaft, and the pump shaft drive piece is connected with the pump chamber subassembly. The pump cavity assembly is provided with a self-suction tank, a suction flow channel and a liquid outlet, the self-suction tank is provided with a liquid inlet, the self-suction tank is communicated with the pump body through the suction flow channel, and the pump body is communicated with the liquid outlet. According to the vertical type self-suction condensate pump, the self-suction pump principle and the condensate pump principle are organically combined, and the vertical type self-suction pump structure and the vertical type condensate pump structure are organically combined, so that the vertical type self-suction condensate pump has the advantages of being low in net positive suction head and high in suction head and has the self-suction function.

The generator sealing oil pump vibration suppression method comprises the steps that S1, the vacuum pressure of a sealing oil tank is adjusted in a staged mode, and the vacuum pressure of the sealing oil tank is adjusted to target vacuum pressure from normal pressure in a staged mode; s2, performing vibration vacuum linkage feedback; s3, the net positive suction head is dynamically compensated, the effective net positive suction head of the sealing oil pump is calculated in real time, and when the difference between the effective net positive suction head of the sealing oil pump and the necessary net positive suction head is smaller than the safety allowance, the liquid level of the sealing oil tank is gradually increased according to the preset lifting height or the circulating flow of the sealing oil is gradually reduced according to the preset flow decrement; and S4, adding a defoaming agent. According to the vibration suppression method for the sealed oil pump of the generator, all the steps have a synergistic effect, through a staged adjustment mode, the phenomenon of gas burst release of the sealed oil tank can be reduced, foam of the sealed oil tank is reduced, the possibility of cavitation of the sealed oil pump is reduced, and therefore vibration of the sealed oil pump is reduced. The invention further discloses a generator sealing oil system.

The application relates to the technical field of cryogenic pump testing, and provides a liquid hydrogen pump testing system and a testing method thereof, the liquid hydrogen pump testing system comprising a low-temperature testing end assembly, a fluid charging and discharging module connected to the low-temperature testing end assembly, and an automatic control system for controlling valves of the liquid hydrogen pump testing system; the liquid hydrogen pump testing system is provided with a cold box and can meet the testing requirement of the performance and critical net positive suction head of a pump under a low-temperature environment of not less than 20K (especially under a 20K liquid hydrogen and 77K liquid nitrogen environment); by testing key parameters such as temperature, pressure, flow rate and liquid level, the external characteristics and cavitation characteristics of a centrifugal submerged pump and a pipeline pump under different inlet pressures and flow rates in a liquid hydrogen temperature zone can be tested and evaluated; by testing the performance of the pump under actual operation conditions, the actual performance of the pump can be accurately evaluated and guidance can be provided for research and development and improvement work.

The utility model discloses a centrifugal pump impeller structure capable of changing the net positive suction head, which comprises a middle shaft, an inner impeller and an outer impeller, the middle shaft is arranged at an inlet of a pump shell, a power shaft penetrates through an assembly hole in the middle shaft, the inner end face of the middle shaft abuts against the inner impeller, and a fixing nut is arranged at the outer end of the middle shaft and is positioned with the outer end of the power shaft; the spiral blades are evenly distributed on the surface of the middle shaft, the inner end face and the outer end face of each spiral blade are provided with a first wedge-shaped arc face and a second wedge-shaped arc face respectively, and gaps are reserved between the inlets and the spiral blades. The centrifugal pump can solve the problems that when an existing centrifugal pump is used, the cavitation phenomenon is prone to being generated, the operation performance of the pump is reduced, and the service life is shortened.

The invention discloses an energy-saving vertical circulating water pump, and relates to the technical field of vertical centrifugal pumps. The invention provides an energy-saving vertical circulating water pump which comprises a pump body, an impeller is rotationally connected into the pump body, the static pressure and the net positive suction head of a water inlet of the pump body both exceed 12 m, a support is fixedly connected to the top of the pump body, and a motor is fixedly installed at the top of the support. The vertical centrifugal pump with the lift of 35 m, the flow of 200 m < 3 > / h and the motor power of 30 kW is selected, meanwhile, the static pressure of an inlet of the vertical centrifugal pump exceeds 12 m and the net positive suction head exceeds 12 m under the conditions that measures are adjusted to local conditions, huge static pressure is utilized, and under the conditions of the same flow and the same power, due to the fact that the static pressure is especially large, the pump body runs stably, and the service life of the pump body is prolonged. And meanwhile, the lift of the pump is improved, considerable energy (electric energy) is saved, the structure is reasonable, noise is low during operation, and stability and reliability are high.

The utility model relates to an anti-vortex single-stage pump with a non-return function. The anti-vortex single-stage pump is characterized by comprising a connecting cover, a motor, a pump body, an impeller, a non-return valve and a sensor, the motor is fixedly mounted at the top of the connecting cover; the pump body is fixedly installed at the bottom of the connecting cover and horizontally arranged, a water inlet and a water outlet are formed in the two ends of the pump body respectively, and a vertical anti-vortex plate is fixed to the position, located at the water inlet of the impeller, in the pump body. The impeller is arranged in the pump body and is fixedly connected with an output shaft of the motor; the check valve is fixedly mounted in the water inlet of the pump body; and the sensor is fixed in the connecting cover. The check valve is fixedly installed in the water inlet of the pump body, the sensor is fixed in the connecting cover and integrally arranged in a pump body unit, the size of a water pump system is reduced, meanwhile, fault nodes are reduced, the vertical vortex prevention plate is fixed to the position, located at the water inlet of the impeller, in the pump body, and the vortex prevention plate is not prone to falling off. The anti-vortex plate can prevent the situation that pre-rotation is generated, vortex is formed, and the unit efficiency and the net positive suction head are affected.

The application relates to the technical field of water supply, in particular to a water supply pump state detection device and method. The water supply pump state detection device comprises a water supply pump, a pressure detection unit, a vibration detection unit and a water pressure pulsation detection unit; the pressure detection unit is connected with the water supply pump and is used for detecting the pressure of the inlet and outlet of the water supply pump; the vibration detection unit is connected with the water supply pump and is used for detecting the vibration of the water supply pump; the water pressure pulsation detection unit is connected with the water supply pump and is used for detecting the water pressure pulsation of the water supply pump. The water supply pump state detection device can monitor the inlet and outlet pressure, water pressure pulsation data and mechanical vibration data in real time, and can analyze the data, comprehensively consider the rated parameters such as the lift and the net positive suction head of the water supply pump, thereby giving potential fault early warning and cause diagnosis of the water supply pump, so as to propose corresponding predictive maintenance solutions.

The utility model discloses a sectional type multi-stage centrifugal pump with a double-suction impeller layout, which relates to the technical field of water pumps and comprises a main shaft and a pump body, and two ends of the main shaft are connected with the pump body through bearings. The pump body comprises a water inlet section, water pumping sections and a water outlet section, double-suction impellers arranged on the main shaft in a sleeving mode are arranged in the water inlet section, the water pumping sections and the water outlet section, a water inlet is formed in one end of the water inlet section, and the other end of the water inlet section is connected with the water pumping sections through flow guide pipes. One end of the water outlet section is connected with the water pumping section through a flow guide pipe; the effective sealing surface between high pressure and low pressure is long, and the leakage rate is very small; the impeller is wide in runner, large in design flow and capable of adapting to various complex working conditions; the specific speed and the efficiency are high; due to double suction inlets, the net positive suction head NPSHr is low, and the effective suction stroke is high; a balancing device or a throttling device is reduced, the efficiency is improved, and the service life is prolonged.

This invention discloses a method and system for controlling the net positive suction head (NPSH) of feedwater pump sets in thermal power plants, belonging to the field of automatic control technology for thermal power generating units. The method involves obtaining the actual available NPSH at the feedwater pump inlet to determine the lower limit of allowable deaerator pressure variation; obtaining the time required for water to flow from the deaerator to the feedwater pump inlet; obtaining the condensate flow increment to prevent insufficient NPSH based on the lower limit of deaerator pressure variation and the time; determining the condensate flow limit value to prevent insufficient NPSH; limiting the output of the automatic deaerator level control module when the actual condensate flow is greater than the condensate flow limit value; and ensuring the automatic deaerator level control module operates normally when the actual condensate flow is less than the condensate flow limit value or when the condensate flow increment is negative. This method prevents insufficient NPSH in feedwater pump sets by limiting condensate flow under emergency conditions, thereby improving the safety and stability of thermal power plant operation.

The invention relates to the technical field of water pump testing, in particular to a cavitation performance prediction method and device for a cutting impeller, equipment and a storage medium. The method comprises the following steps: acquiring a cavitation test data set of the fixed impeller at at least one preset test flow point; calculating cavitation occurrence judgment data under a plurality of first flow working conditions of fitting the cutting impeller to the fixed impeller; according to the cavitation test data set and the cavitation occurrence judgment data, the net positive suction head of the cutting impeller at each test flow point is calculated; and drawing a cavitation performance curve according to the net positive suction head of the cutting impeller at each test flow point. By adopting the method, the cavitation performance of the cutting impeller can be predicted, and the cavitation test difficulty and economic cost of a manufacturer are reduced.

The present invention discloses a design method for an anti-cavitation centrifugal pump impeller. By designing the working surfaces of the long blades and short blades and the backs of the long blades and short blades as positively curved twisted concave surfaces, the flow area of the intermediate flow surface is increased, and the flow velocity is reduced to lower the required net positive suction head (NPSH) and improve the anti-cavitation ability of the impeller. When the impeller designed by this method is at the limit low pressure at the inlet, there is basically no bubble aggregation phenomenon, the improvement effect of the anti-cavitation performance is remarkable, and the efficiency is significantly improved under the small flow rate condition; within the entire range of the inlet pressure design requirements, the impeller has good anti-cavitation performance. The anti-cavitation performance of the impeller is improved without sacrificing the impeller efficiency, without changing its fixed external dimensions and interfaces, and only the blade profile needs to be locally modified on the basis of the existing impeller. Moreover, it is easy to promote and has high application value.

The utility model discloses an automatic liquid level control system and decompression equipment applying the same, the automatic liquid level control system is used for a decompression device and comprises a liquid seal device, a liquid level sensing mechanism and a tower bottom product pump, a liquid inlet pipeline of the liquid seal device is communicated with the side wall of a tower body of the decompression device, and a liquid outlet pipeline of the liquid level sensing mechanism is communicated with the tower bottom product pump. A liquid outlet pipeline of the liquid sealing device is communicated with a liquid outlet pipeline of the pressure reducing device, the tower bottom product pump is communicated with the liquid outlet pipeline of the liquid sealing device and the liquid outlet pipeline of the pressure reducing device, and the tower bottom product pump is also connected with the liquid level sensing mechanism to realize pressure balance. According to the automatic liquid level control system, the liquid level sensing mechanism is adopted to control the rotating speed of the product extraction pump, so that the net positive suction head of the tower bottom product pump is counteracted, the stability of liquid drainage of the tower bottom product pump in a pressure reduction state is improved, and the problem that the product pump is damaged due to small height difference between a pressure reduction device and the tower bottom product pump is solved. And the phenomenon that a product pump at the bottom of the tower does not discharge liquid or the liquid discharge is unstable due to insufficient feeding pressure heads is avoided.

According to the double-end liquid inlet impeller for the self-priming pump, a rotating shaft is fixedly arranged in the center of the impeller in a penetrating mode, the impeller is a hollow disc-shaped impeller, arc-shaped blades are transversely arranged in the center of the interior of the impeller, and an upper end water inlet and a lower end water inlet are formed in the upper end and the lower end of a shell of the impeller respectively; an outer side water outlet is formed in the arc-shaped outer side of a shell of the impeller, a connecting middle shaft is arranged at the bottom of the center of an arc-shaped blade, the outer side edge of the arc-shaped blade is flush with the transverse horizontal center line of the outer side water outlet, and a layer of inner pump shell is additionally arranged on the outer side of the impeller through water inlets formed in the upper end and the lower end. Water flowing in from two ends is pressurized and integrated, so that small net positive suction head can be effectively realized, the suction lift is greatly improved, and the suction lift can reach 8 meters under normal pressure.

The present invention discloses a method for hydraulic design data modeling of a submersible well pump. The method includes five steps: sensing and acquisition, hydraulic data enhancement, hydraulic performance prediction, intelligent material matching, and modeling output. The present invention relates to the technical field of pump hydraulic modeling analysis, specifically referring to a method and system for hydraulic design data modeling of a submersible well pump. By using a physics-informed adversarial generative network combined with a spatio-temporal Kriging interpolation algorithm, three-dimensional flow field data is enhanced; a multi-modal graph neural network integrating physical control losses is constructed to achieve dynamic prediction of performance indicators such as pump body efficiency, head, and net positive suction head; based on a corrosion-wear coupling model and a reinforcement learning algorithm, the lifespan, cost, and processability of candidate materials are evaluated, and the optimal combination is intelligently recommended, providing systematic support for the design of high-efficiency, low-cost, and long-life submersible well pumps.

The utility model relates to a centrifugal impeller, including upper end disc, lower end disc and a plurality of long blades, the central place of lower end disc is provided with the use assembly unit, the assembly unit is provided with the shaft hole, the assembly unit includes upper end and lower end, long blade is arc and surrounds the upper end part setting, upper end disc is provided with the water inlet part, the central place of water inlet part is provided with the water inlet, the inner diameter of water inlet is greater than the diameter of upper end, long blade includes connecting part and the extension from the connecting part to the upper end part periphery from top to bottom, the side of extension is arc and sets up and with the side of connecting part smooth transition, the upper end surface of extension is inclined and sets up and the same as long blade arc rotation direction with the inclined direction, the short blade that is arc is provided between adjacent long blades, short blade sets up in connecting part one end close to extension. Through adopting above technical scheme, reduce the necessary net positive suction head of pump, promote the anticavitation performance, effectively divide the runner, restrain the bad vortex and secondary flow, reduce the flow loss.

The application discloses an anti-cavitation impeller, and relates to the technical field of centrifugal pumps. Each group of blade units comprises an inlet edge forward blade and a regular blade, and the inlet edge forward blade and the regular blade are arranged alternately in the circumferential direction; the radially outermost edge of the inlet edge of the inlet edge forward blade is located radially outward of the radially outermost edge of the inlet edge of the regular blade; the radially innermost edge of the inlet edge of the regular blade is located radially inward of the radially innermost edge of the inlet edge of the inlet edge forward blade; and the spacing angles between any two adjacent groups of blade units are not equal. Therefore, the impeller of the embodiment of the application can maintain stable anti-cavitation performance in a wide flow range, is not only suitable for the delivery of high-temperature easy-vaporization medium with a super-low net positive suction head, but also lays a good flow field foundation for subsequent adaptation to gas-liquid two-phase flow conditions, and effectively improves the operation stability and working condition adaptability of the chemical centrifugal pump.

The application discloses a composite double-suction fire pump impeller for low cavitation, which comprises an inlet impeller 2, a splitter impeller 3 and a double-suction impeller 4 which are sequentially arranged on a pump shaft 1. The multiple impeller composite structure effectively improves the flow state, and the impellers complement each other to achieve certain synergistic effect on the flow path. The blade inlet angle of the inlet blade 21 is beta1, the blade inlet angle of the splitter blade 31 is beta2, and the blade inlet angle of the double-suction blade 41 is beta3, wherein (a beta1 + b beta2) / (b beta2 + c beta3) = 0.6-0.85, a is the number of the inlet blades 21, b is the number of the splitter blades 31, and c is the number of the double-suction blades 41. Compared with the prior art, the application optimizes the inlet angle of the blades, modifies the composite impeller structure, significantly improves the flow state, reduces the required net positive suction head of the pump, and effectively reduces the noise and vibration.

The invention discloses a water pump anti-cavitation device and a control system, the water pump anti-cavitation device comprises N first flow passages and N second flow passages which are connected in parallel, each first flow passage comprises a first water pump and a first regulating valve which are connected in series, and each second flow passage comprises a second water pump and a second regulating valve which are connected in series; the first water pump and the second water pump are both provided with flow limiting values, the first adjusting valve automatically adjusts the opening degree of the valve according to the flow value output by the first water pump so that the output flow value can be smaller than or equal to the flow limiting values, and the second water pump adjusts the power supply frequency so that the output flow value can be smaller than or equal to the flow limiting values. The limited flow value is smaller than the critical cavitation flow value, the limited flow value is a positive root of a rooting result obtained through calculation of the effective net positive suction head, the necessary net positive suction head and the safety margin, and the critical cavitation flow value is a flow value obtained when the effective net positive suction head is the same as the necessary net positive suction head. According to the invention, the operation cost can be reduced while cavitation can be effectively prevented.

The invention discloses a method and a device for determining a net positive suction head warning value and a method and a system for monitoring a cavitation state, and relates to the technical field of polycrystalline silicon production. The method for determining the net positive suction head warning value comprises the steps that net positive suction head NPSHa and first area information of a circulating pump are obtained, and the net positive suction head NPSHa is determined according to second area information; the first area information comprises a safety margin S and a necessary net positive suction head NPSHr; the second area information comprises a container discharging temperature real-time value, a dichlorosilane component content real-time value, a trichlorosilane component content real-time value and a silicon tetrachloride content real-time value; and according to the net positive suction head NPSHa and the first area information, the net positive suction head warning value NPSH of the circulating pump is determined. According to the embodiment of the invention, the method can achieve the real-time monitoring of the cavitation state.

The invention discloses a method and a system for detecting the net positive suction head of an electronic water pump for a vehicle, and the method comprises the steps: placing a detected electronic water pump in a detection space of which the internal temperature can be adjusted, and connecting the detected electronic water pump with a water storage tank through a circulation test loop; the circulation test loop can detect the inlet side pressure and the outlet side pressure of the vehicle electronic water pump, control and detect the flow and the temperature of a liquid medium, carry out net positive suction head detection on the detected electronic water pump under each working condition, automatically compare and control the vacuumizing rate and the flow in the test process, collect corresponding net positive suction head data, and carry out automatic detection on the net positive suction head. And finally calculating to obtain the net positive suction head. Manual intervention is reduced as much as possible, the influence of the liquid medium temperature and the environment temperature on the electronic water pump net positive suction head test is fully considered, and the accuracy of the test result can be improved.

This utility model relates to a vertical pipeline centrifugal pump, including a drive source, a pump body, a shaft system, an impeller, and a sealing component. The drive source has an output shaft; the pump body is connected to the drive source and has a suction channel; the shaft system is mounted on the output shaft; the impeller is mounted in the pump body, and the end of the shaft system facing away from the drive source is connected to the impeller; the sealing component is located at the mating point between the shaft system and the pump body; a streamlined guide boss is provided in the area of ​​the suction channel of the pump body near the impeller inlet, and the guide boss gradually contracts along the liquid flow direction; different areas of the pump body have differentiated wall thicknesses, and reinforcing ribs are provided in the areas of concentrated stress on the pump body, with the reinforcing ribs integrally formed with the pump body. This utility model guides the liquid flow evenly into the impeller through the streamlined guide boss in the suction channel, reducing eddies and low-pressure areas, thus reducing the net positive suction head (NPSH) and extending the impeller life; the differentiated wall thickness adapts to the stress in different areas, and the reinforcing ribs can disperse stress and solve the problem of deformation and cracking.