Tri-Clamp fittings are very popular and widely used. The connection is made up of two identical, flat-faced flanges connected by use of a clamp. A gasket is placed into the grooves on the faces to prevent leakage.
I-Line fittings are ideal for use in more demanding applications. The connection is male and female nested together and secured with a gasket and clamp. They’re able to handle greater temperatures, vibrations and pressures than standard Tri-Clamp fittings. They're also designed to help eliminate over compression of the gasket. Different manufacturers may use different letters in place of the "I."
Bevel Seat fittings are ideal for use in lower pressure applications such as milk transfer. The connection is male and female, with the faces of each being angled 45° to create a metal-on-metal seal. The male is threaded and the two are joined by use of a nut. A gasket can be added for higher pressure applications.
Butt Weld fittings are designed to be welded on site at their end(s) to connect pipe(s) together and can allow for change in direction, change in diameter, pipe branching or ending. These fittings then become part of the system for transporting fluids in a safe and efficient manner. Good for high pressure, high temperatures and corrosion resistance.
Socket Weld fittings involve a pipe being inserted into the recessed area of the fitting. Both the pipe and the fitting are square cut allowing for easy welding and installation. Socket welds resist around half the strength of butt welds so they are mainly used for small bore pipeline.
NPT Threaded fittings have a tapered thread profile. The OD of the male thread tapers down from the base. The matching female thread has a larger OD at the opening, tapering down as it goes in. The taper allows them to form a seal when torqued as the flanks of the threads compress against each other.