Channeling a large amount of axial shaft

Mechanical seal sealing surface have a certain specific pressure, so as to play a seal, which requires the mechanical seal to have a certain amount of compression spring, a thrust to the seal face, rotate it so that the sealing surface than produce the required sealing pressure. To ensure that a specific pressure, the mechanical seal pump shaft can not have too much requirements channeling, generally less than 0.5 mm to ensure that. But in the actual designs, the design of the unreasonable and often have a huge amount of channeling shaft, the use of mechanical seals is very unfavorable. This phenomenon often occurs in multi-stage centrifugal pumps, especially during the pump is started, more than channeling.

Work automatically change the balance disc balance disc and balance the axial clearance between the ring b, thus changing the pressure on both sides of the balance disc before and after, producing an axial force in the opposite direction of the force to balance the axial force. Moving in the rotor inertia and transient fluctuations in the pump operating conditions, operation of the rotor is not stationary in a certain axial position of equilibrium. Balance disc always ran around in the state. Balance disc during normal operation of the axial channeling is only 0105 ~ 011 mm, to meet the mechanical seal to allow the amount of 015 mm axial channeling requirements, but the balance disc in the pump start, stop, drastic changes in working conditions are likely when the axial channeling much higher than the mechanical seal to allow the amount of axial channeling.

Industrial pumps after a long run, the balance disc and balance ring friction and wear, the gap b with the increase of the axial mechanical seal Clearance increasing. The role of the axial force, the suction side of the sealing surface of the pressing force increases, the sealing surface wear increased, until the sealing surface damage, loss of seal. Spit out the side of the mechanical seal, with the balance disc wear and tear parts of axial channeling rotor sealing requirements greater than the amount of axial channeling, the sealing surface of the clamping force decreases, reaching less than sealing requirements, and ultimately both sides of the pump The mechanical seal all lost seal.

2 axial force is too large

In the course of the mechanical seal is not able to withstand the axial forces, if there is axial force, the impact of the mechanical seal is serious. Sometimes, because of the axial pump unreasonable force balance mechanism design and manufacture, installation, use and other reasons, resulting in axial force is not balanced out. Mechanical seals to withstand an axial force, operating temperature will be higher when the gland, for the polypropylene media, will be melted at high temperatures, so the pump starts to lose the sealing effect soon after, when the pump is stationary seal face is there intermittent spray leakage phenomenon.

3 shaft deflection is too large

Also known as seal mechanical seal is a contactless rotary axial dynamic seal, which is in the fluid media and the role of elastic components, the two lines perpendicular to the axis tightly seal faces, the relative rotation, so as to achieve sealing effect, thus requiring to be between the two seals in good condition. However, due to the irrational design of pumps, pump operation, mechanical seal installed in deflection produced at large, so that the sealing surface between the Shouli Bu uniform, resulting in seal is not effective.

4, no auxiliary or auxiliary irrigation system flushing system set unreasonable

Auxiliary mechanical seal flushing system is very important, it can effectively protect the sealing surface, play a cooling, lubrication, wash away debris and so on. Sometimes designers do not configure a secondary irrigation system reasonably, reach the sealing effect; sometimes even though the designers to design a support system, but because of impurities in the fluid, fluid flow, pressure is not enough, rinse mouth unreasonable position because the design , too, fail to seal.