Tom; I'm attempting to put together a vacuum system with I a Robinair 15300vacuum pump. I saw the system you helped set up for Steve Schlumpf and I have a few questions if you would be so kind to answer. First: Why is there an air filter under the relief valve? Second: What is an air silencer and who makes them? Unfortunately, I've already purchased the HoldFast rotary adaptor but yours look so much better. Thank you, Jim Colombo
