Rubber vs. silicon
Wherever metal meets metal, such as a connector and a control cabinet, there is usually a seal sitting in between. It must have similar temperature and media resistance characteristics to the materials that make up the other components in the connector or gland, otherwise it will become the weak link in the chain. Fluorocarbon elastomers (FKM) are the best solution here, but are expensive. These resist the effects of weather, ageing, ozone and chemicals, and withstand temperatures of up to 200 degrees Celsius. In moderate ambient conditions, ethylene propylene diene monome rubber (EPDM) is a good alternative. FKM does have one small disadvantage. It is not suitable for very cold environments, and should not be used at temperatures under -20 degrees Celsius. Silicon is a better choice for refrigerated warehouses or other very cold or hot environments. On the other hand, it is not suitable for use at very high temperatures such as in furnaces. Just as important as the seal’s material is its design. Seals used in food processing should not have any gaps or crevices where residues could settle. The seals of the SKINTOP® HYGIENIC range, for example, adjust to the shape of the sealed surfaces and join flush without creating any gaps.
For users, finding the right products is not always easy. Many order stainless steel components just to be on the safe side, without knowing the media with which the connectors will come into contact. Alternatively, users dial back their requirements and use improved standard products for their cables and connectors, in the knowledge that these will often need replacing. There is no one right answer here, the best way to proceed is to weigh up the various advantages and disadvantages. The experts at Lapp know their products extremely well. Users should always consult them before potentially making the wrong choice.