One failure mode of some types of bellows seals is rupturing bellows that lead to premature failure. This rupturing has two main causes. The first cause is when the torsional drive, which in normal operation goes through the spring, is transmitted through the bellows as the spring disengages from one end. The second cause is particulates or sharp objects in the water that tear the bellows.
To prevent this failure mode, some seals incorporate a patented drive mechanism that always transmits the drive through a metal-to-metal interface and that encases the majority of the bellows in a metal shroud during operation. These features ensure that the soft rubber is not exposed to particulates or sharp objects.
Seal faces require optimum running conditions to maintain the longest life possible. This means they require clean fluid to pass between the faces. The friction between the two faces generates heat. If this heat builds, the faces distort or the fluid film evaporates, leading to even more friction. Eventually, the faces will generate excessive heat and the seal will fail. Directed barrier fluid is a clean, cool fluid that passes around the faces. It can reduce heat generation and excessive friction between the faces, increasing mechanical seal life and the reliability of the pump.
Component seals can be unbalanced, which means that all the product pressure acts to close the gap between the seal faces and causes face contact. Hydraulically balanced seal designs can counteract this challenge by allowing pressure to act over a thinner area than the seal face running track area, reducing the closing force. This allows the seals to operate in higher pressures and at higher shaft speeds, generating less heat and face wear. Typically, balanced seal faces will have a longer operating life than unbalanced seals—whether they are component or cartridge seals.
Shaanxi DaoLin Mechanical & Electrical Co.,Ltd
Room1107, Building B, Sail Times Plaza, Hou Wei Zhai, Wei Yang
District, 710085, Xi’an City, Shaanxi Province, China
Tel.:+86(029)84523807-802 Fax: +86(029)84523807-808