Precision parts processing pump parts are usually composed of many parts, according to the working state of each part at work, can be divided into three types: rotating parts, fixed parts and handover parts.
impeller
The impeller is the core component of the pump, which can make the water obtain kinetic energy and produce flow. The impeller consists of a blade, a cover plate and a hub. When selecting impeller materials, in addition to considering the mechanical strength under the action of centrifugal force, it is also necessary to consider the wear and corrosion resistance of the material. At present, most impellers are made of cast iron, cast steel and bronze.
The impeller can be divided into two types: single-suction impeller and double-suction impeller. The single-suction impeller is unilateral suction, and the front cover plate of the impeller is asymmetrical with the back cover plate. Double suction impeller shown on both sides of the water, the impeller cover is symmetrical, general large flow centrifugal pump most of the use of double suction impeller.
The impeller can be divided into closed type, open type and semi-open type according to its cover plate. Sewage pumps often use closed impeller single-channel or double-channel structure to prevent debris clogging; Sand pump is often used semi-open and open structure to prevent sand on the impeller wear and blockage.
Pump shaft
The pump shaft is used to rotate the pump impeller. Common materials are carbon steel and stainless steel. The pump shaft should have sufficient torsional strength and sufficient stiffness, and its deflection should not exceed the allowable value. The impeller and shaft are connected by a key. The key is the connection between the rotating body, the centrifugal pump generally uses the flat key, this key can only transfer torque and can not fix the axial position of the impeller, in the large and medium-sized pump impeller axial position is usually used shaft sleeve and tight shaft sleeve nut to locate.
volute
Its water part requires good hydraulic conditions. When the impeller is working, the flow rate increases gradually along the expanding section of the volute. In order to reduce the hydraulic loss, the water flow velocity along the expanding section of the volute should be a constant in the design of the pump. After discharging from the volute, the water flows into the pressure pipe through the conical diffusion tube. The function of the conical diffusion tube on the volute is to reduce the speed of the water flow, so that part of the flow head is converted into the pressure head.
Pump casing
The pump shell is composed of several parts, and its inner cavity forms an impeller studio, an suction chamber and a water pressure chamber. The shape and size of the pump housing depend on the impeller structure form and size and the shape and size of the suction chamber and pressure chamber determined by the hydraulic design. The pump shell mainly has two kinds of end cover pump shell and middle open pump shell. The end cover pump shell is divided along the radial surface perpendicular to the axial line of the pump to form the pump body and the pump cover. It is mostly used for single-stage pumps. The pump shell is divided along the plane through the pump shaft line, which is often used for double-supported volute pumps, such as the cross-shaft single-suction double-suction pump, which is mainly composed of impeller, pump shell, pump shaft, bearing and packing sealing device parts.
Pump base
The pump seat is provided with flange holes for fixing with the base plate or foundation. The bottom of the pump shell is provided with a water discharge screw hole, so that it can be used to empty water when the pump is stopped for maintenance. In addition, a drain screw hole is provided at the bottom of the transverse groove of the pump seat to discharge the leaking water droplets from the packing box at any time.
Shaft sealing device
In order to prevent high pressure water from flowing out through the rotation gap and air from flowing into the pump, the shaft seal device must be set up. The shaft seal device has a packing box seal and a mechanical seal.
