Don’t put a sumo wrestler in a boxing ring!
Boxing is a sport of punches and shocks. It requires a nimble and hard body with tough muscles to tolerate the punches. On the other hand, a Sumo wrestler is slow, fat, and soft.
The soft and heavy body of a sumo wrestler makes him immobile and unable to tolerate quick punches. Thus, he would collapse within minutes in the boxing ring.
Using soft-seated ball valves in hot oil applications has similar consequences!
The operating temperature of thermal oil systems can go up to 399° C, and most hot oil systems operate between the pressure range of 45-65 psi. This makes it extremely difficult to contain and control hot oil. Additionally, the high temperature of the oil needs to be maintained in order to keep its viscosity as low as possible. The type of valve plays a key role here.
Akin to the tough body of boxers, valves used in hot oil applications have full metal bodies and are provided with jacketing. Jacketing involves covering the valve body with a jacket material while leaving a gap between the jacket and the valve body. Media such as hot steam is passed through this space so that the media flowing through the valve remains hot and fluid, preventing it from hardening due to cooler temperatures.
Choosing the right type of valve for hot oil
Jacketed gate valves and ball valves are the most commonly used valves in hot oil applications. Both valves bring distinct advantages and disadvantages to hot oil operations.
Gate valves
- Require less pipeline space due to vertical design
- Slow to open and shut due to long actuation time
- Cost lower than ball valves
Ball valves
- Open and shut quickly due to short opening turn
- Are heavier as compared to Gate Valves.
- Cost higher than gate valves
While the body of gate valves is made entirely of metal, ball valves tend to have different types of seats to ensure better sealing performance. These could be metal seats or non-metal i.e soft seats. This is where ball valves might create issues in hot oil applications.
Soft seats tend to damage and fail at temperatures as low as 150° C. If the seat wits away, it could lead to serious leakage from the valves.
What happens when valves in hot oil leak?
When a soft seat is damaged, the hot media can leak out of the valve. It could either leak out of the valve from the packing or travel further down the line even when the valve is closed. In case the media is highly inflammable, the leaked media can catch fire.
Metal seated valves should be preferred instead of soft-seated ball valves for total safety and efficiency in hot oil applications.
Gate valves have full metal bodies and can ensure reliable safety at relatively lower costs than ball valves.
Conclusion
Valve design and environmental conditions play a key role in valve selection for hot oil applications. Given the chances of fire incidents, safety is a major concern along with the efficiency of the valve. Hence, the users must work closely with their valve manufacturing partner when selecting a valve for such sensitive applications. Here, full metal gate valves occupy less space and deliver safety and reliability in operations at a far lower cost than ball valves.
To know more, write to us at evalve@ipcvalves.com