hot mechanical seals Constant regulation
Proper selection of mechanical seals is the key to preventing pump leakage
(Continued) In order to keep the sealing surface between each other, the spring has played a mechanical seal and the movement of the spindle between the constant regulation. When the use of artificial rubber seal between the rotating surface and the spindle, the elastomer will move back and forth on the spindle. This repeated friction action, will wear the anti-corrosion material on the spindle, the loss of the main axis of the oxide film protective layer, and ultimately the friction surface in the spindle to form a wear groove, resulting in leakage of liquid from the trench and increase the necessary maintenance workload Or even replace the spindle. In order to solve this problem, a replaceable sleeve is usually installed in the packing box.
However, the only permanent solution to the problem of corrosion wear is to remove its internal dynamic seal. Now, most of the major sealing factories produce non-corrosive wear seals to prevent corrosion of the pump parts.
Balanced and unbalanced seals
The balance of the mechanical seal has a significant effect on the sealing pressure of the contact surface. This sealing pressure depends on the effective cross section of the seal itself and the pressure in the packing box.
The cross section of the opposite side of the rotating surface of the unbalanced seal is completely exposed to the pressure range of the packing box, which creates a high sealing pressure between the sealing surfaces, which increases the operating temperature and accelerates the wear rate. In the high temperature working conditions or the liquid has a large corrosive and friction in the case, will greatly reduce the mechanical seal life.
The mechanical seal to balance, can reduce the sealing pressure, to extend the service life of the seal. Generally with a step with the spindle and sleeve, reduce the effective cross-section of the surface, you can achieve the above objectives. But do not adjust the net seal pressure to a level close to zero, because the results may cause the seal between the working conditions of instability, and may be due to sudden changes in the seal will blow open.
The answer to these sealing problems may be the use of non-balanced seal, for some services, may use non-balanced seal to achieve better results. For example, in some applications, there may be more emphasis on the safety problems associated with liquid leaks than the sealed service life. In this case, the selection of the seal may be understood to be more desirable to have a higher sealing pressure. Likewise, the increase in operating temperature may be insignificant when a cooler liquid is used.
Regardless of the consideration, when the packing box pressure exceeds 50psi, it is generally recommended to use a balanced seal.
Sealed and sealed
The most common practice is to install the seal inside the packing box. However, this practice requires that the wet end of the pump be removed when the seal is repaired, and the main benefit is that the sealed sanitation is easy to control.
The outer seal is mounted in such a way that the direction of the static sealing surface is reversed and the rotating unit on the spindle is located outside the packing box gland. The outer seal has the following five major benefits:
1. Installation is easy; 2. Cost is relatively low; 3. Can be continuously monitored and cleaned;
4. Suitable for small packing boxes where internal sealing can not be installed;
5. Because of its position close to the bearing, the spindle deviation of the less difficult impact.