Jacketed vessels are used in many industries and can be used to remove the elevated heat of reaction (heat reactor vessel) or reduce the viscosity of high viscous fluids. There are three basic types of external jacketed heat transfer surfaces: conventional jacket, half pipe jacket and dimple jacket, which is attached to the outside of the vessel by welds. Internal coils can also be utilized and can be used as a stand-alone option or in combination with any of the other types of external jackets.