Before we select an appropriate ball valve, there are many factors we need to take into consideration. Seat type is one of important perspectives.

Soft Seated Ball Valve

The seat ring in contact with the ball part is made of soft material, such as PTFE, RPTFE, Nylon, Devlon, Peek and so on. For floating ball valve, there is only one soft seat ring for one side seat. But for trunnion ball valve, there are a metal seat ring along with a soft seat insert. But we still call this as soft seated ball valve, since the seat ring directly touching the ball is of soft material. The soft seated ball valve is suitable for clean fluid without any particulates and relatively lower temperature. They’re great for applications where chemical compatibility is important, and where the tightest seal is key.

Metal Seated Ball Valve

In contrast with soft seated ball valve, the seat ring of metal seated ball valve is made of metal, like SS316, Stellite, and TCC. It is designed to address some shortcomings of soft seal ball valve. The ability to withstand severe conditions like abrasive fluids with particulates, high viscosity heavy oil or slurries, high temperature or cryogenic conditions makes it more durable than soft seated ball valve. But metal seated ball valve has higher torque value. Meanwhile, a very small amount of leakage as per standard is allowable due to its metal-to-metal design.

In conclusion, for clean fluid within general temperature range ( normally less than 250°C，soft seated ball valve is an economical option. While, for severe condition with high temperature, abrasive solids or high viscosity, you should choose the more lasting one, metal seated ball valve, considering the cost of downtime and maintenance.