Lepu Seal - A Professional China Mechanical Seal Manufacturer providing Cartridge Seal, Grundfos Mechanical Seal And We offer free sample!

Mechanical seal related introductionMechanical seal

by:Lepu Seal     2023-01-04

Introduction to Mechanical Seals




2021-05-24 14:57







Mechanical seal (mechanical seal) refers to at least one pair of end faces perpendicular to the axis of rotation, under the action of fluid pressure and the elastic force (or magnetic force) of the compensation mechanism, and the cooperation of the auxiliary seal to keep fit and relatively slide to prevent fluid leakage. device.

The elastic loading mechanism and the auxiliary seal are mechanical seals of metal bellows, which we call metal bellows seals. In light-duty seals, rubber bellows are also used as auxiliary seals. Rubber bellows have limited elasticity, and generally need to be supplemented by springs to meet the loading elasticity.“Machinery Seal”commonly referred to as“machine seal”.

A mechanical seal is a shaft seal device for a rotating machine. Such as centrifugal pumps, centrifuges, reactors and compressors and other equipment. Since the transmission shaft runs through the inside and outside of the equipment, there is a circumferential gap between the shaft and the equipment, and the medium in the equipment leaks out through this gap. If the pressure inside the equipment is lower than the atmospheric pressure, the air leaks into the equipment, so there must be a Shaft sealing device to prevent leakage. There are many types of shaft seals. Because mechanical seals have the advantages of less leakage and long life, mechanical seals are the most important shaft sealing method in these equipments in the world. Mechanical seal is also called end face seal, which is defined in relevant national standards as follows:“A device for preventing fluid leakage that is composed of at least one pair of end faces perpendicular to the axis of rotation, under the action of fluid pressure, the elastic force (or magnetic force) of the compensation mechanism, and the cooperation of auxiliary seals to keep fit and slide relative to each other.”




The main components

Moving ring, static ring, cooling device and compression spring (depending on the specific equipment)



auxiliary seal

Sealing ring (O-shaped, X-shaped, U-shaped, wedge-shaped, rectangular flexible graphite, PTFE coated rubber O-ring, etc.)


Elastic Compensation Mechanism

Spring, push ring, spring seat and key or various screws



Classification

Divided into single end face, double end face; balanced type, unbalanced type; arbitrary rotation direction, fixed rotation direction……



Principle overview

The commonly used mechanical seal structure is composed of stationary ring (static ring), rotating ring (moving ring), spring seat of elastic element, set screw, auxiliary sealing ring of rotating ring and auxiliary sealing ring of stationary ring, etc. The anti-rotation pin is fixed on the gland to prevent the stationary ring from rotating.

Rotating rings and stationary rings are often also called compensation rings or non-compensation rings according to whether they have axial compensation capabilities.



Installation and decommissioning

1. Before starting, the sealed chamber should be filled with liquid. When transporting solidified medium, steam should be used to heat the sealed cavity to melt the medium. The car must be cranked before starting to prevent the soft ring from breaking due to sudden start.

2. For mechanical seals that use the external oil sealing system of the pump, the oil sealing system should be started first. Stop the oil sealing system last after parking.

3. After the hot oil pump is out of service, the cooling water in the oil seal cavity and the end face seal cannot be stopped immediately. The cooling water should be stopped only when the oil temperature at the end face seal drops below 80 degrees, so as not to damage the sealing parts.



run

1. If there is a slight leakage after the pump is started, it should be observed for a period of time. If the leakage does not decrease after 4 hours of continuous operation, the pump should be stopped for inspection.

2. The operating pressure of the pump should be stable, and the pressure fluctuation should not exceed 1 kg/cm2.

3. When the pump is in operation, avoid pumping out to avoid dry friction and damage to the sealing surface.

3. The sealing condition should be checked frequently. During operation, when the leakage exceeds the standard, the heavy oil is not more than 5 drops/min, and the light oil is not more than 10 drops/min. If there is no improvement within 2-3 days, the pump should be stopped to check the sealing device.
Custom message
Chat Online 编辑模式下无法使用
Leave Your Message inputting...