We fabricate jackets for steam and hot oil heating, for ease of handling viscous fluids. All Types: Plug, Ball, Gate, Check, Control , Relief Valves and other piping components, such as Fittings, Pumps, Meters and Pipe. All Materials: Carbon Steel, Stainless Steel, Monel and others. Flow Fab Bolt-On Jacket These jackets are formed to fit around a valve or other piping system component. Sections (usually 2 pieces) bolt together around the unit, the heating chamber being separate from the unit. Bolt-on Jackets offer full coverage. They can be re-used when the basic valve is replaced. Also, these are ideal for use on valves or other piping components already in your system as they can be installed without removing the unit from service.