Why are gate valves not advisable for use in partially open or closed systems?

Gate valves are designed primarily to be either fully open or fully closed, making them unsuitable for use in partially open or closed systems. When a gate valve is not fully opened or closed, it can cause a condition known as cavitation – where vapor bubbles form and collapse within the valve. This can lead to excessive vibration and wear not only on the valve itself but also within the adjoining piping and fittings, which may eventually create leaks or failures in the system.

Moreover, when a gate valve is in a partially open position, the flow tends to create turbulence, which increases the risk of erosion and can lead to a decrease in the overall efficiency of the system. Therefore, when dealing with variable flow conditions, other types of valves, such as globe or ball valves, are typically recommended because they can maintain better flow control and handle the operational stresses associated with partial opening.