Each centrifugal pump is composed of hundreds of parts, and the basic structure of the centrifugal pump is composed of six parts.
Impeller
Volute Casing
Shaft
Bearing
Seal ring
Stuffing box
These components can be subdivided into the wet end and mechanical end.
The impeller is the core part of the centrifugal pump, it has high speed and high output, the impeller on the blade and plays a major role, the impeller should pass the static balance test before assembly. The inner and outer surfaces on the impeller are required to be smooth to reduce the friction loss of water flow.
The impeller can be generally divided into single-suction and double-suction two kinds, single-suction impeller for single-sided suction, small flow pump impeller is mostly this type. Double-suction impeller is two-sided suction, large flow pump impeller are used double-suction impeller
Impeller design is the most important factor in determining the performance of a centrifugal pump. A properly designed impeller optimizes the flow rate. Centrifugal pump type water pump impeller mainly has the following 3 forms, closed type, semi-open type, open type
Closed impeller: It consists of blades and front and rear cover plates. The closed impeller is more efficient and more difficult to manufacture. It is the most used in centrifugal pumps. Suitable for conveying clean water, solutions, and other clean liquids with small viscosity and no particles.
Semi-open impeller: there are two general structures one is the front semi-open, by the back cover and blade composition, this structure impeller efficiency is low, in order to improve efficiency need to be equipped with adjustable gap sealing ring another for the back semi-open, by the front cover and blade composition, because can be applied with the closed pump impeller the same sealing ring? Efficiency and closed impeller are basically the same, and the blade in addition to conveying liquid, but also has: back blade or vice impeller sealing role. The semi-open impeller is suitable for conveying liquids containing solid particles, fibers, and other suspended matters. The semi-open impeller is less difficult to manufacture, lower cost, and is adaptable, in recent years in the refinery chemical centrifugal pump application gradually increased, and used to transport clear water and near clearwater liquid
Open impeller: only the blade and blade reinforcement, no front and rear cover impeller. The number of open impeller blades is less than 2-5 pieces. Water pump impeller efficiency is low, the application is less, mainly used for conveying high viscosity liquid and slurry liquid.
Acts as a support fixation and is connected to the bracket where the bearing is mounted
The impeller mounted on the shaft, the pump shaft is connected to the motor by coupling and transmits the torque of the motor to the impeller, so it is the main part for transmitting mechanical energy.
Bearings constrain the relative motion of the shaft (rotor) and reduce friction between the rotating shaft and the stator
Sealing rings are also known as leak reduction rings prevent the leakage of the pumped liquid
The stuffing box is mainly composed of packing, water seal ring, packing cylinder, packing gland and water seal tube. The function of the stuffing box is mainly to close the gap between the pump casing and the pump shaft, so that the water inside the pump will not flow outside and the air outside will not enter the pump. Always keep the vacuum inside the pump! When the pump shaft and the packing friction heat will rely on the water seal tube water to the water seal ring to make the packing cool! Keep the normal operation of the pump. Therefore, we should pay special attention to the checking of the stuffing box during the operation tour of the pump! The packing should be replaced in about 600 hours of operation.
