What type of valve must steam boilers be equipped with at the bottom?

Steam boilers are required to be equipped with a blowoff valve at the bottom to facilitate the proper drainage and maintenance of the boiler. The main purpose of a blowoff valve is to allow for the removal of sediment and other impurities that accumulate in the boiler's water at its lowest point. By discharging these contaminants, the blowoff valve helps ensure the efficiency and longevity of the boiler, preventing issues such as corrosion and scale buildup.

While check valves, relief valves, and isolation valves are important components in various mechanical systems, they serve different functions. A check valve is primarily used to prevent backflow, a relief valve is designed to release excess pressure to prevent system overpressure, and an isolation valve is used to shut off flow in a system for maintenance purposes. However, none of these components fulfill the specific need for efficiently removing sludge and deposits that can affect boiler performance, making the blowoff valve the essential choice for steam boilers.