other parts of boiler 2
分类：轮机英语小册子
Air release cock: These are fitted in the headers, boiler drum, etc., to release air when filling the boiler or initially raising steam.
Blow down valve: This valve enables water to flow down or empied from the boiler. Tt may be used when partially or completely emptying the boiler.
Scum valve: A shallow dish positioned at the water level is connected to the scum valve. this enables the blowing down or removal of scum an impurities from the water surface.