Mechanical seal parts are one of the mechanical basic components with delicate and complex structures, and are key components of various pumps, reaction components, turbocompressors, submersible motors and other equipment. Its sealing function and service life depend on many factors, such as model selection, machine accuracy, installation and application of mechanical seals, etc.
Sealcon, as a professional China mechanical seal manufacturer, is an expert in the selection, installation and application of mechanical seal parts.
1. The requirement of mechanical seal for machine precision
(1) The radial runout tolerance of the shaft (or shaft sleeve) where the imported mechanical seal is installed at the mechanical seal part should not exceed 0.04-0.06mm at most.
(2) The axial movement of the rotor does not exceed 0.3mm.
(3) The runout tolerance of the cartridge mechanical seal on the surface of the shaft (or shaft sleeve) between the positioning end of the sealing cavity and the sealing end cover shall not exceed 0.04-0.06mm at most.
2. Recognition of mechanical seal parts
(1) Acknowledge that the installed seal is of the type required.
(2) Before installation, carefully check with the general assembly drawing to see if the number of parts is complete.
(3) Select the mechanical seal driven by the parallel spring, and the spring has left and right rotation, which must be selected according to the rotation force of the rotating shaft.
Depending on the working conditions and the properties of the medium, mechanical seal parts include high-temperature and low-temperature-resistant mechanical seals, high-pressure and corrosion-resistant mechanical seals, particle-resistant mechanical seals, and mechanical seals that are used to light hydrocarbon media that are easily vaporized. Select mechanical seals with different structures and materials according to different uses.
(1) The main parameters of model selection are: sealing cavity pressure (MPa), fluid temperature (°C), working speed (m/s), fluid characteristics and useful space for sealing installation.
(2) The basic principle of model selection is: according to the pressure of the sealing cavity, determine whether the sealing structure should be balanced or unbalanced, single-end or double-end, etc.; Or non-contact type; according to the temperature and fluid properties, determine the conflict pair and auxiliary sealing materials, and accurately select the mechanical seal circulation protection system such as lubrication, erosion, heat preservation, cooling, etc.; Single or wave springs, built-in or external.
The installation method varies with the type of mechanical seal and the variety of the machine, but the installation method is almost the same. The installation process and precautions are as follows:
(1) Determination of installation size. During installation, the installation size of the mechanical seal should be guaranteed according to the product's operating instructions or samples.
(2) Before loading, the shaft (sleeve) and gland should be free of burrs, and the bearing should be in good condition; the seals, shaft, sealing cavity and gland should be cleaned. In order to reduce the conflict resistance, the part where the mechanical seal is installed on the shaft should be coated with a thin layer of oil for smoothness. Considering the compatibility of the rubber O-ring, if oil is not suitable, soapy water can be applied. The structure of the floating static ring without anti-rotation pin should not be oiled, and should be installed in the gland dry.
(3) Install the static ring together with the gland on the shaft first, taking care not to touch the shaft, and then install the moving ring assembly. The set screw of the spring seat or transmission seat should be tightened evenly in several times. Before the gland is not fixed, push the compensating ring by hand for axial tightening. After loosening, the compensating ring can automatically spring back without jamming, and then lock the gland bolts evenly.