What are the installation requirements for the boiler’s blowdown devices?

In my opinion, one aspect is the location of the openings and the reinforcement, and the other is the hole diameter and piping design

This post was last edited by hzliangke on 2009-12-20 at 19:01. 1. The liquid impurities passing through the sewage valve have a high content, are highly viscous, and cause significant flow resistance. Stop valves with an indirect path should not be used as drain valves. In practical applications, drain valves often use gate valves, sector valves, or inclined stop valves. The nominal diameter of the blowdown valve ranges from 20 to 65 mm; the nominal diameter of the blowdown valve at the bottom of the boiler shell in horizontal shell boilers must not be less than 40 mm. The adoption of the aforementioned type of drain valve and the control of the nominal diameter are both aimed at ensuring smooth drainage and reducing resistance during drainage. 2. Boilers with a rated evaporation capacity of 1 t/h or more, or a rated steam pressure of 0.7 MPa or more, shall be equipped with two series-connected blowdown valves in their blowdown pipes. The drain valve should always be kept tight; it is not uncommon for boiler water shortage incidents to occur due to the drain valve not being closed properly or leaking. Two drain valves are connected in series on the drain pipe, with the aim of improving its tightness and safety. 3. Each boiler should be equipped with an independent blowdown pipe. The waste pipe should have as few bends as possible to ensure smooth waste discharge, and it should be connected to a safe outdoor location or a waste expansion tank. When a pressurized expansion tank is used, safety valves should be installed on the blowdown tank. When multiple boilers share a single main blowdown pipe, two or more boilers shall not discharge simultaneously. 4. For the blowdown valve of the boiler, the blowdown pipe should not be connected by threads, as threaded connections cannot meet the requirements for tightness nor withstand the impact of the blowdown water. 5. The blowdown elbow at the bottom of the boiler should be fabricated from thick-walled seamless steel pipes; cast iron elbows should not be used as a substitute. All connections of the sewage pipes shall be made using flange connections. There should be sufficient space for operation and maintenance in the vicinity.