BelleFlex™ Home / Tech Tips / Understanding Joints

How do joints work, and when do they fail?

A joint works when its pieces form a water-tight or gas-tight seal. When two pipes are intended to be joined, the pipes are typically formed with a flange at the end. To create a firm seal, a gasket is positioned between the two flanges. Nuts and bolts—often including a Belleville disc spring—secure the pieces in place.

One of the main concerns about joints is their mechanical integrity. They must be designed, installed, and maintained to withstand industrial conditions. A joint can fail for multiple reasons, such as the following.

Gasket set
Gaskets are designed to withstand a certain amount of pressure. If a gasket is operating under too much pressure—due to industrial conditions or perhaps simply over-tightening—it will be crushed. A gasket must be “set” (or pressed) with the appropriate amount of force.

Vibration
The vibration of machines can cause loosening of various parts, including joints. Engineering design must take vibration into account.

Thermal expansion
Materials often expand and contract when exposed to varying temperatures. If different components expand and contract at different rates, gaps can form within the joint.

BelleFlex™ engineers provide assistance in the use of Belleville disc springs to protect the mechanical integrity of joints.