A. Inline sewage pump to ensure the quality of parts
The mechanical seal of the sewage pump must be tested for sealing performance before leaving the factory, and there is a certificate of conformity. After long-term operation of the mechanical seal, the moving ring and the static ring wear, the spring and shaft corrosion wear, the sealing rubber ring wear, aging, deformation, etc., can cause leakage of the seal, and new parts must be repaired or replaced. The sealing surfaces of the moving ring and the stationary ring shall not have cracks, corners, scratches, pitting, flashing and eccentric wear, and scratches and pitting may not penetrate the entire sealing end face. If the repaired static and dynamic ring is used, the height of the boss of the static and dynamic ring is not less than 3 mm, and the height of the single boss is not less than 1 mm, so as not to affect the heat dissipation. After the moving ring is installed, it should be able to move flexibly on the shaft. After pressing the moving ring to the spring, it should be able to bounce back freely, keeping the static and vertical rings parallel and parallel. The specifications of the static and dynamic ring sealing rubber ring are in accordance with the drawings. The surface shall not be damaged, uneven in thickness and uneven in hardness and hardness. The sealing rubber ring shall be replaced during overhaul. The outer surface of the spring is clean and free of rust. The length profile test and pressure test should be carried out before use. The pressure difference of each set of springs at the specified compression length should meet the requirements. The pressure error of each set of springs in the specified compression length meets the requirements. The free length tolerance does not exceed 0.5mm, the compression amount cannot be too large or too small, and the required error is ±2mm. The sealing sleeve and the pump shaft cannot be of the same material, and the parallelism tolerance of the end faces on both sides and the non-perpendicularity tolerance to the axis do not exceed ±0.20 mm.
B. Inline sewage pump ensures sufficient cooling and lubrication
Adjust the opening of the cooling line regulating valve to ensure that the mechanical seal cooling line is unobstructed. When the tank pump is opened, the venting valve should be drained to clean the gas in the sealed chamber.
C. Inline sewage pump to ensure installation accuracy
When disassembling the mechanical seal of the water pump, the static and dynamic rings should be cleaned, and a small amount of clean lubricating oil should be applied on the friction auxiliary surface. The high pressure end and the low pressure end should be taken into consideration. When installing the static ring gland, the force should be uniform to prevent the pressure deviation. Check with the feeler gauge. The deviation between the upper and lower positions is not more than 0.05mm. Check the matching clearance between the gland and the outer diameter of the shaft. The circumference should be even. The allowable deviation of each point is not more than 0.1ram. The radial runout of the pump shaft where the mechanical seal of the pump is installed shall not exceed 0.05 mm. Before putting the pump cover and sealing the end cap, carefully check the installation and positioning dimensions of the mechanical seal. If the positioning dimension does not meet the requirements, the steel gasket can be adjusted between the bushings, but the steel pad has high precision and the thickness difference does not exceed 0.01mm. Measuring the radial runout of the mechanical gland and the end face bounce of the sealing surface meet the requirements. For the mechanical seal that has been operated, if the gland is loose and the sealing surface is moved, the static and dynamic ring parts must be replaced, and should never be re-tightened for continued use. Because the original trajectory of the friction pair changes after such loosening, the sealing performance of the contact surface is easily destroyed.
D. Inline sewage pump adjusts the end face specific pressure
End face specific pressure is an important parameter related to sealing performance and service life, and it is related to the sealed structure type, spring size and medium pressure. If the end face is too large, the friction pair will be added. If the pressure is too small, it will leak easily. The manufacturer usually gives a suitable range. The specific pressure of the end face is generally 3 to 6 kg/cm2. Adjusting the specific pressure is to adjust the compression size of the spring. The free length of the spring is indicated by A. The spring stiffness produces a load of k when the unit compression is generated. The specified specific pressure is indicated by P. These are the parameters given by the manufacturer. The size after compression is indicated by B, then P/A-13=k, resulting in 13=A-e/k, which is the size after the spring is mounted and compressed. If the size of the spring after installation is too large, the thickness of the adjustment pad can be increased between the spring seat and the spring. If the size is too small, the thickness of the adjustment pad is reduced, and the thickness of the adjustment pad is measured by a micrometer.
