All of the following are parts of a rising stem gate valve assembly except?

A rising stem gate valve assembly is designed to control the flow of fluids in piping systems and consists of several key components. The handle, stem, and disc are integral parts of the valve's operation.

The handle is used to operate the valve, allowing for manual control over opening and closing the valve. The stem connects the handle to the disc, transmitting the rotational motion from the handle to vertically move the disc up and down within the valve body. The disc is the actual component that seals the flow of fluid; when the disc is raised by the stem, the valve opens, and when lowered, it closes.

In contrast, a weight is not a component associated with the rising stem gate valve assembly. Weights may be used in other types of valves or mechanisms to apply force, but they do not play a role in the operation of a rising stem gate valve. This distinction clarifies why the weight is the correct answer as it does not belong to the essential components of a rising stem gate valve assembly.