8 results about "NPSH" patented technology

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 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.

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 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.

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.

This invention provides a method, apparatus, electronic device, and storage medium for optimizing the operation scheme of a water injection system. The method includes: determining the operation scheme of the water injection system to be optimized; determining the net positive suction head (NPSH) curve of each pump in the water injection system based on the fluid parameters of the fluid in each pump; determining the economic indicators of the water injection system based on the head performance curve of each pump and the fluid parameters; and optimizing the operation scheme of the water injection system to be optimized based on the economic indicators and the NPSH curve to obtain the optimal operation scheme of the water injection system. The optimal operation scheme obtained thereby enables the water injection system to operate in a non-cavitation or low-cavitation range while maintaining energy-saving conditions. This overcomes the shortcomings of traditional schemes where frequency conversion control of pump output cannot avoid the cavitation phenomenon of pumps in the water injection system, resulting in excessively high operation and maintenance costs. This achieves the maximum reduction in operation and maintenance costs.