We have a customer that makes Intermediate Bulk Containers, a type of thousand-liter transport tank. They wanted a valve resistant to solvents that they could trust.
We created a valve with a disk that was fully encapsulated in ETFE – a highly chemical resistant fluoropolymer similar to Teflon. This encapsulation ensured that when the valve is closed, only EFTE and none of the structural materials touched the solvent in the tank. We achieved this through a process of over-molding, where two dissimilar materials are used to mold one final part.
We then created an offset seal on the disk. An offset seal works like a cork in a wine bottle. The walls of our valve are slightly tapered so that the diameter decreases closer to the back of the valve. The final motion of the disk and the stem push the disk backwards, forcing it into a more narrow section of the valve body. The result is a mechanical seal that is not possible on a normal butterfly valve. The seal worked because we were able to use our experience and precision techniques to mold a valve that is exceptionally round.
Finally, our assembly team employed technology common in the automotive fuel tank industry to create a computer controlled leak testing cell that could quickly and accurately test every valve we manufactured. This testing was able to precisely measure leaks and quantify the consistency of acceptable parts. Computerized testing allowed us to get a stream of precise data about the consistency of the parts even if all the parts were in the acceptable range.