We are designing a high pressure heat exchanger. Can we know what fitments can be used for it?
Redbeard.. is very correct in that you need to be specific as to what pressure and temperature as well as material you need. These all play a factor in the design. He is also correct about ANSI flanges. Their nominal rating and their real rating are different depending on material and temperature. The other choice is butt weld connections. There are very common in certain serivices. We used this type of connection for vessels, heat exchangers and valves in 1000 psi steam service.
Well, first please recognize that the term 'high pressure' is not well defined. Do you mean 100 PSI ? 1,000 ? 10,000 ? Much depends on what size you are talking about. Also temperature, and material of construction. Years ago while I was working in a lab running tests at 15,000 psi I was talking with my brother who was working on an oil production platform. I mentioned the high pressure, 15,000 psi, only to have him call that 'medium pressure' as he was working at much higher pressures [as he said: You've heard of pressures in feet of water column, but consider miles of rock] For up to around 300 psi [1,000 if you are really careful] you can use tapered pipe threads [NPT in the US]; straight pipe threads [NPS in the US] with gasket are good to maybe 2500 psi [5,000 if you are really careful], and after that cone and gland. Flanges can also be used, and there are a viriety of flange designs. Note however, that there is much misnaming; a 'class 300' flange is often called a '300 lb' flange, whereas the 'class 300' flange is good for 300 psi if made of cast iron; steel ones can go a lot higher. The ASME website will have information on this, as will Perry's Handbook of Chemical Engineering. Swagelok and Parker both offer a range of fittings good up to around 10,000 psi, but they are not especially cheap, not compared to plain vanilla tapered pipe threads. Parker's are cheaper, but I have had better luck with Swagelock's. However, check whatever pressure vessel codes there may be in your area. Also important will be what fittings your customers demand. WHile it is possible to buy a flanged heat exchanger and adapt it to pipe threads, or vice versa, it is an extra step and involves extra cost and clearances, which your customers might not accept.
