How many different basic designs of gate valves are there?

Gate valves are an essential component in various piping systems, designed to allow or block the flow of liquids or gases. There are two fundamental basic designs of gate valves: the rising stem gate valve and the non-rising stem gate valve.

The rising stem design features a stem that rises as the valve is opened, which provides a visual indication of the valve's position. This type is particularly useful in applications where it is beneficial to see whether the valve is fully open or closed.

In contrast, the non-rising stem design keeps the stem stationary while the disc moves up and down to open or close the valve. This design is advantageous in applications where space is limited, as it does not require extra vertical clearance for the stem.

These two basic designs serve different operational needs and environments, making them essential for various applications in water and fuel systems. Therefore, the correct response aligns with these recognized categories in the context of gate valve designs within the field of water and fuel systems maintenance.