Which valve is preferred when flow conditions tend to deposit or coke valve seats?

The preferred choice when flow conditions are likely to lead to the deposition or coking of valve seats is the conventional disc globe valve. This type of valve is designed with a seat that provides a tighter closure, which helps prevent flow from leaking when the valve is closed. The design allows for better maintenance of flow and pressure conditions, which can help minimize the chance of materials depositing on the seats.

In scenarios where coking might occur, such as in high-temperature or high-pressure applications, the ability of the globe valve to close tightly is essential. Additionally, the configuration of the globe valve means that it can be more easily cleaned or serviced compared to other valve types. In contrast, some other valves, such as ball valves or butterfly valves, may not provide the same level of tight closure, making them less suitable for conditions that lead to deposits on the valve seats.

Globe valves also tend to be more effective in throttling applications because they allow for more precise control over the flow rate, which is another reason why they are favored in situations where flow conditions can negatively affect valve performance. This precision helps in maintaining stable operations, further minimizing the risk of deposits forming.