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fuyangby@126.com
86 15188770013
Selection of mechanical seals for slurry pumps
Clearly define the sealing form and function
The sealing forms of slurry pumps include packing seal, mechanical seal, and impeller seal. The function of the slurry pump seal is to prevent the slurry in the slurry pump body from leaking between the shaft and the slurry pump body, so sealing components must be used. When selecting mechanical seals, it is necessary to consider different working conditions.
Select based on specific parameters and operating conditions
According to the pressure of the sealed chamber, determine whether the sealing structure adopts balanced or unbalanced type, single end face or double end face, etc. For example, under certain high-pressure conditions, it may be necessary to choose a balanced double end mechanical seal.
According to the working speed: determine whether to use rotary or static, fluid dynamic pressure or non-contact type. Generally speaking, high-speed operating conditions may be more suitable for fluid dynamic mechanical seals.
Based on temperature and fluid properties, determine the friction pair and auxiliary sealing materials, as well as correctly select mechanical seal circulation protection systems such as lubrication, flushing, insulation, and cooling. When the temperature of the medium is less than 70 ℃, fill the sealing chamber with No. 30 engine oil (remove the cooling water); The friction pair material is embedded with hard alloy, and different friction pairs can be selected according to different media; The spring does not require medium contact, thus overcoming the blockage of high viscosity and easily crystallized materials, ensuring the compensation flexibility of the compensating ring, and extending the sealing service life.
According to the effective space for installing the seal: determine whether to use multi spring, single spring, or wave spring, internal or external installation.
Replacement of mechanical seals for slurry pumps
Preparation before replacement
Confirm sealing model: Confirm whether the installed seal is consistent with the required model, ensuring that the replaced seal can adapt to the slurry pump.
Parts inspection and cleaning: Carefully compare with the final assembly drawing to check if the quantity of parts is complete. Clean the moving ring, stationary ring, shaft sleeve and other components, and check whether there are scratches, cracks and other defects on the surface of the moving and stationary rings. The presence of these defects can cause serious leakage of the mechanical seal.
Check installation dimensions: Before starting the slurry pump, the attached device of the mechanical seal and the cooling and lubrication system should be checked for completeness and smoothness; At the same time, manually rotate the coupling to check if the shaft rotates easily. If the rotation is heavy, check if the installation dimensions are correct.
Replacement process
Dismantling old seals: After parking, conduct maintenance by first removing the impeller of the slurry pump, and then gradually dismantling the old mechanical seals.
Install new sealing components
Determine installation dimensions: During installation, the installation dimensions of the mechanical seal should be ensured according to the product's user manual or sample.
Cleaning related components: The shaft (bushing) and cover should be free of burrs, and the bearing condition should be good; Seals, shafts, sealing chambers, and glands should all be cleaned thoroughly. Floating static rings without anti rotation pins should not be coated with oil and should be installed in a dry manner under the cover.
Component installation: First, install the static ring and the cover on the shaft together, being careful not to touch the shaft, and then install the dynamic ring component. Before fixing the cover, manually push the compensating ring for axial compression. After loosening, the compensating ring can automatically rebound without any jamming phenomenon, and then evenly lock the cover bolts.
Testing and operation after replacement
Static pressure test: Before normal driving, a static pressure test is required to check the sealing effect of the end face, sealing ring, and sealing end cover of the mechanical seal. If there are any problems, they should be checked and resolved one by one.
Formal operation inspection
When the temperature of the conveying medium is too high, too low, or contains impurity particles, flammable, explosive, or toxic, corresponding measures such as sealing, flushing, cooling, and filtering must be taken.
Before operation, open the medium and cooling water valves, check if all the gas in the sealed chamber is discharged to prevent leakage caused by static pressure, and then start the machine for operation.
After driving, observe whether the work is normal and stable, whether there are any abnormal torques caused by shaft rotation, as well as abnormal noises and overheating phenomena.
This article originates from https://www.fuyangpumps.com/news/450.html. Please indicate the source when reprinting.
(Editor in charge: Slurry Pump https://www.fuyangpumps.com/)
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