In a perfect world where all connections are perfectly aligned and access to the connection is easy, we would not be talking about over-compression. Unfortunately in the real world, it is slightly different. Piping is hardly ever aligned perfectly, so we have to use force to bring ferrules together and make a leak proof connection. The force we apply comes from the clamp that we us to bring two parts together. Each sealing material has compression limitations, which means you cannot endlessly keep on closing the clamp around the ferrules. By doing so you destroy the gasket. The animation in the background shows what happens when you over-compress a gasket. This chapter will explain in more detail what the consequences are of over-compression.
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Due to misalignment, we are exposing the gasket to uneven forces. As you can witness in the video below the bottom side of the gasket is compressed much more than the top part. This results in a situation where there is gasket material pushed inside the tubing causing a ridge. This ridge has a significant impact on the performance of the whole system. The flow capacity is reduced and the chances of solid material building up on both sides of the gasket are eminent. (The video at the top of this chapter illustrates this with the green particles)
Side effects over-compression
Regardless if we are over-compressing because of misalignment or simply because we feel we need to, the side effects of over-compression are overwhelming. We have created several video animations illustrating the effects. In the first video, we show the effect of the rubber ridge sticking inside the flow path. Over a longer period of exposure to steam (SIP) and product flow, the gasket weakens and parts will eventually break out. And where do they go?
The gasket ridge that we discussed has a dramatic effect on the flow performance of a system. Each ridge is creating a pressure drop, imagine the effect of a cascade of connections. The video below illustrates the effect of 5 connections with a 2 mm gasket ridge, gravity drop of 10L water.