The structure of the centrifugal pump can be basically divided into horizontal centrifugal pump and vertical centrifugal pump according to the position of the shaft. At the same time, according to the type of the extrusion chamber and the suction mode, it can be divided into a volute type and a vane type. It consists of four parts: prime mover, impeller, pump casing and shaft seal.
First, the structure and working principle of the centrifugal pump
1. Structure of centrifugal pump The structure of centrifugal pump can be divided into horizontal centrifugal pump and vertical centrifugal pump according to the position of the shaft. At the same time, according to the type of extrusion chamber and the suction method, it can be divided into volute type and guide vane. The centrifugal pump consists of four parts: the prime mover, the impeller, the pump casing and the shaft seal device. The prime mover is the power unit of the centrifugal pump, which is usually connected to the pump body through a coupling drive or other transmission to provide kinetic energy; There are generally 6-12 pieces of curved blades in the impeller. The main function of the blades is to transfer the mechanical energy of the prime mover to the liquid to be transported. The pump casing is also called the volute. The function of the transducing device is to collect the liquid thrown by the impeller. The sealing device is a seal between the pump shaft and the pump casing. Its function is to prevent high pressure liquid from leaking from the inside of the pump casing along the shaft or the outside air entering the pump casing inward.
2. Working principle of centrifugal pump Take common water pump as an example. Before starting, the pump casing should be filled with liquid first. After starting, the impeller rotates at high speed under the motor. When the impeller rotates, the water pressure at the inlet of the impeller decreases below atmospheric pressure. The pressure of the water in the radial direction of the impeller increases continuously higher than the atmospheric pressure, so that a certain suction force is formed in the inlet pipe. Under the atmospheric pressure of the outside, the water at the lower part pushes the inlet valve, enters the pump casing along the inlet pipe, and is sucked in and out by the impeller. Water pipes. Such low water can be continuously pumped high.
Second, the common failure of the centrifugal pump and repair recommendations
There are many reasons for the failure of the centrifugal pump. There are inherent equipment failures, installation failures, operational failures and selection errors. For example, the pump cannot start normally, the pump does not discharge water or the flow is insufficient, the pump vibration and noise, the bearing heat, the pump super power. , cavitation, etc.. When judging the failure of the centrifugal pump, it should be combined with the basic indicators of equipment status and rich maintenance experience. The following describes some common faults.
1, start failure
The motor can't start normally. If the motor is the prime mover, firstly use the motor to dissipate the heat sink fan to see if the rotation is flexible: if the flexibility may be the start capacitor failure or capacity reduction, replace the same value of the start capacitor; if it does not move The rotor is stuck, add grease or clean the foreign body of the card rotor when cleaning the rust.
If the reverse rotation of the pump encounters such a situation, it should be stopped immediately at the first use. If the motor should be exchanged, any two phases of the three-phase power supply can change the direction of rotation of the pump. If the diesel engine is powered, the belt should be considered. Connection method.
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