What to check before installing the mechanical seal of horizontal multistage centrifugal pump?
Centrifugal pumps play an important role in production. Horizontal multi-stage centrifugal pumps rely on the rotation of the impeller to make the medium produce centrifugal movement to realize fluid transportation. Most of the pump shafts of horizontal multistage centrifugal pumps use mechanical seals. What to check before installing the mechanical seal of horizontal multistage centrifugal pump?
Three ways to deal with excessive power consumption of D-type horizontal multistage centrifugal pump
1. Inspect the pump shaft and bearings
The pump shaft and bearing are the core components of the rotating part of the centrifugal pump. The mechanical seal device cooperates with the pump shaft and the mechanical seal box to install the moving ring and the shaft rotates with the stationary ring. The dimensional accuracy and installation accuracy of the fixed shaft and bearing are directly related to the unit time of the mechanical seal. Before the formal installation of the mechanical seal, it is important to check the pump shaft and bearing of the centrifugal pump to ensure that the pump shaft and bearing meet the installation requirements of the mechanical seal. Use a dial indicator to monitor the shaft radial runout and momentum parameters. According to the material characteristics of the moving and static rings of the mechanical seal and a large number of experiments, it can be known that the momentum parameters and straightness of the rotating shaft of the centrifugal pump cannot be greater than 005mm. If the value exceeds this standard value, the centrifugal pump bearing box needs to be disassembled according to the operating specifications to check the size of the shaft Whether the accuracy meets the requirements of the drawings. Whether the bearings are severely worn, whether the pump shaft and the installation accuracy of the bearings meet the design requirements. Repair or replace damaged bearings or pump shafts in time to avoid affecting the sealing effect and service life of the mechanical seal.
2, inspection machine sealing
The use of centrifugal pumps is accompanied by the wear and aging of various parts. Due to the characteristics of working conditions and installation accuracy, the sealing box will have different degrees of wear and tear. If it cannot be handled in time, leakage will occur. The inspection items of the machine-sealed box mainly include ①The static seal of the mechanical seal and the installation on the machine-sealed box. When checking, pay attention to see whether the wear of the mating surface meets the requirements. The size tolerance of the mating surface due to wear cannot be greater than that of the O-ring The maximum extrusion gap will otherwise cause leakage of the medium due to inadequate sealing. ②The mechanical seal box is installed on the pump casing with bolts. If the positioning is inaccurate due to mechanical vibration or other reasons, the mechanical seal box will have radial displacement and the pump shaft concentricity will exceed the design requirements. Mechanical seal The concentricity of the rotating parts and the stationary parts on the upper axis is out of tolerance, causing the water seal eccentric wear and the dynamic and static ring eccentric wear to cause uneven seal wear and elastic compression. The mechanical seal leaks. In the same way, if the bolt hole between the mechanical seal and the mechanical seal box is excessively worn, the rotating part of the mechanical seal will be radially displaced during the operation of the centrifugal pump. The rotating part of the mechanical seal and the stationary part will appear to be concentrically out of range, resulting in eccentric wear and leakage.
3, check the integrity of the mechanical seal
Before installing the mechanical seal, it is necessary to perform a system inspection. Firstly, check whether the end faces of the moving ring and the static ring are worn or bruised. Avoid the tight contact between the moving ring and the static ring after installation, which affects the sealing effect or the mating surface is too fast Wear. Check whether other components are fully equipped for damage or missing. Check whether the surface of each component is clean and clean the relevant parts with gasoline to avoid dust, rust, iron filings or other foreign objects
