On a boiler blowoff system, a valve requiring five 360° turns to close is known as what?

A valve that requires five complete turns to close is classified as a slow opening valve. This characterization stems from the valve's mechanical design, which necessitates multiple rotations of the handle to achieve a fully closed position. The slow operation allows for a gradual change in flow, reducing the risk of surges or sudden pressure changes in the system, which can be critical in maintaining safety and operational stability.

In contrast, a quick opening valve would require significantly fewer turns or even a quarter turn to operate, allowing for rapid adjustments to flow. An isolating valve functions to entirely shut off flow or isolate sections of the system and can vary in opening and closing speed but is not defined by a specific number of turns. A non-return valve, or check valve, is designed to allow flow in only one direction and does not operate based on turns, but rather relies on pressure differentials to function.

Understanding the operational characteristics and applications of these different types of valves is essential for effective boiler blowoff system management and ensuring systems operate within safe parameters.