After spending many years working with and designing sheet metal components, it has become obvious that if one of the major hinge manufacturers were to produce a two part weld on hinge (316L st st) then the design and manufacture of Hazourdous Environment enclosures in Stainless Steel would be so much easier. They would still need certification, but the basic problem of door sealing would be done and dusted. I have seen over half a dozen designs ranging from tapped Block hinges, flat spot weld on hinges, but all have basic faults ranging from cost through to chemical entrapment (electropolishing process). The hinge would need to be designed to allow the door to be easilly located but also for movement in the "Z" direction, a simple enough thing to do. For some reason some designers either over engineer or simply done understand basic concepts.
On a slightly unrelated note this certainly rings true for me. I work with IP67 bulkhead connectors and the seals are NEVER designed properly. My idea of a "proper" seal would be an o-ring or gasket with a compression stop. They always use gaskets without a compression stop - much too easy to over-compress and spill out over the sides (unless you can absolutely guarantee the correct tightening torque setting is used!)
Gareth, this is so similar to what goes on in enclosure manufacture. It is a relativelly easy task to stop over compression, you just need to be aware of the danger. For example over compression in neoprene gaskets is as bad as under compression. Over compression will resault in the gasket losing its memory, (no spring back and so no seal). Anything over 30% is dangerous (check spec with gasket manufacturer)
