Centrifugal pump structure, the main components of the centrifugal pump 1. Introduction: A centrifugal pump mainly by the pump, impeller, seal ring, rotary shaft, shaft sealing and other components, and some centrifugal pumps are also equipped with guide wheel, inducer, balance Disk and so on. 2. Pump body: the pump housing, including the suction chamber and the pressure chamber. (1) inhalation chamber: its role is to make the liquid flow evenly into the impeller. (2). Pressurized liquid chamber: Its role is to collect liquid and send it to the lower impeller or guide discharge pipe, at the same time reduce the liquid velocity, the kinetic energy further into pressure energy. The pressure chamber has a volute and guide wheel in two forms. The volute is named after the runner is spiral. Fluid flows along the helix and decreases velocity as the cross section of the runner increases. As a result, the kinetic energy becomes pressure energy. The stator is commonly found in segmented multistage pumps. So that the structure is simple and compact. The energy conversion between the primary impeller and the secondary impeller adopts a guide wheel, and the liquid flows along the guide passage defined by the guide wheel to the entrance of the secondary impeller. 3. Impeller: It is the only element in the centrifugal pump that delivers energy to the liquid. The pump, through which the pump becomes the pressure energy of the liquid, increases the pressure of the liquid. Impeller key fixed on the shaft, with the shaft driven by the prime mover rotation, the prime mover through the leaves of the energy transfer to the liquid. According to the passage of liquid into the impeller, it can be divided into single suction impeller (with an inlet on one side of the impeller) and double suction impeller (liquid flows symmetrically from both sides of the impeller into the impeller flow passage). In accordance with the liquid flow direction relative to the main axis of rotation of the classification, the impeller can be divided into: radial impeller, axial impeller and Francis impeller. According to the structure of the impeller classification, can be divided into closed impeller, open impeller and semi-open impeller. Closed impeller consists of a number of blades and their cover and wheel on both sides of the composition of the adjacent two leaves and wheel cover, the disk is surrounded by the liquid space is the flow path; open impeller, only the leaves, no Wheel cover and wheel disc; Semi-open impeller, only on one side of the blade wheel. 4-axis: it is an important part of the transmission of mechanical energy, the torque of the prime mover is transmitted to the impeller through it. Pump shaft is the main part of the pump rotor, the shaft is equipped with impeller, bushings, balance disc and other parts. Pump shaft bearing support at both ends, in the pump for high-speed rotation, so the pump shaft to carry capacity, wear resistance, corrosion resistance. Pump shaft material is generally used carbon steel or alloy steel and quenched and tempered. 5. Sealing ring (split ring) The sealing ring is a seal installed between a rotating impeller and a stationary pump casing (combination of middle section and guide vane). Its role is to control the gap between the two methods to increase the resistance of liquid flow between the high and low pressure pump chamber to reduce leakage. 6. Bush Sleeve is used to protect the pump shaft from corrosion and wear. When necessary, the sleeve can be replaced. 7 · Shaft seal The shaft seal between the shaft of the pump and the front and back covers is referred to as the shaft seal, which mainly prevents the liquid in the pump from leaking and the air entering the pump to achieve the purpose of sealing and preventing cavitation of the pump caused by the air inlet. Shaft seal in the form of three general: with a skeleton of the rubber seal, packing seal and mechanical seal. 8 · Axial force balance device (1) Causes of axial force a. Axial force A1 due to different fluid pressure distributions on both sides of the impeller (low pressure on the wheel cap side and high pressure on the wheel disc) is oriented from the impeller back to the impeller inlet. b. The reaction force A2 generated by the fluid flowing in and out of the impeller in a different direction and at a different speed, in the opposite direction to A1. Therefore, the total axial force A = A1 - A2 is generally in the same direction as A1 (generally, A2 is small). (2) balance of axial force a. Adopting double-suction impeller: the impeller is symmetrical on both sides, the fluid is sucked in from both ends, and the axial force automatically cancels to balance. b. Open the balance hole or install the balance pipe: A: Open several balance holes on the impeller wheel with respect to the suction inlet. B: In order to avoid opening the balance hole, due to the disturbance caused by the mainstream to increase the hydraulic loss, Balance pipe can be set to replace the balance hole, which uses a small tube inlet pressure to the back of the roulette. C: the use of balanced blades: cast a few radial ribs in the back of the impeller disk,? Pieces of the impeller to drive the fluid in the back of the gap to accelerate the rotation, increasing centrifugal force, so that the impeller back pressure was significantly reduced. c. The use of thrust bearing axial force. Generally small single suction pump thrust bearing can withstand all the axial force to prevent the shaft from moving. (3) multi-stage centrifugal pump axial force balance: a single-stage centrifugal pump with the same method b symmetrical arrangement of the impeller c using the balance drum to partially balance the axial force d automatic balancing plate, all automatic balance shaft To the force.