Ball ball valves are, by design, one of the most widely used shut-off and control elements in the Oil & Gas industry. However, their geometry presents a particular challenge when the process involves viscous, solidifying fluids or substances with a high melting point: the lateral cavities formed between the ball and the body can become a trap for the fluid. The heating jacket is the technical answer to this problem.
What is a heating jacket?
A heating jacket —also known as a heating jacket in English— is a space or cavity designed and integrated into the valve body through which an external heating fluid circulates (usually steam, hot water, or thermal oil). Its function is to keep the process fluid at a controlled temperature, preventing phenomena such as solidification, crystallization, or excessive increases in viscosity that could compromise valve operation.
Structurally, the jacket surrounds all or part of the valve body, creating a completely sealed and independent secondary circuit from the process fluid. It has an inlet and an outlet for the heating fluid, connected to the plant’s heating system.
When is it necessary to use a heating jacket?
A full bore ball valve generates, in both the open and closed position, two lateral cavities between the spherical obturator and the valve body. Under normal conditions, this does not pose any issue. But when the process fluid tends to solidify, crystallize, or drastically increase its viscosity as it loses temperature, these cavities become dead zones where the fluid is trapped and can solidify.
How a heating jacket works in a ball valve
The heating jacket in a ball valve consists of an integrated circuit in the body that surrounds the critical areas —mainly the lateral cavities and, depending on the design, also the packing box and the neck— through which an external heating fluid circulates.
This circuit keeps the valve body temperature above the solidification point or the minimum operating temperature of the process fluid, ensuring that:
- The lateral cavities remain free of solid deposits at all times.
- The fluid in contact with the seats maintains sufficient flowability so as not to damage them during operation.
- The actuation system —manual, pneumatic, or electric— always operates within the design torque limits, without overloads caused by fluid resistance.
- Tightness is not compromised by accumulations or deformations associated with solidification and melting cycles.
The FHT Valves solution
At FHT Valves we design and manufacture ball valves with heating jackets for the most demanding process conditions in the Oil & Gas sector. Each project is carefully analyzed by our engineering team: type of fluid, process and ambient temperature, available heating medium, applicable standards, and specific requirements from the client or project engineering.
The result is a fully integrated ball valve, with its heating circuit designed, manufactured, and tested as part of the assembly, ready to operate reliably even under the most adverse conditions.