The primary function of a blowdown valve is to control the concentrations of suspended & total dissolved solids (TDS) in the boiler. Boiler blowdown is a severe service application which results in rapid erosion and wearing out of conventional valves.
Continuous Blowdown (CBD) valves are designed to operate in continuous open position by releasing water continuously through a blowdown tap near the boiler water surface, thereby maintaining the TDS level in the boiler drum. IndiTech Continuous Blowdown Valve is an angle type valve with a needle shaped trim in a venturi diffuser. The venturi diffuser provides sufficient area for the high velocity flashing water, thereby avoiding choked flow.
Intermittent Blowdown (IBD) valves are designed to operate at predetermined intervals by releasing water & accumulated sludge periodically through a blowdown tap near the bottom of the boiler. The primary requirement of these valves is to provide tight shut-off even after repetitive blowdown operations. Earlier, these two functions (blowdown and sealing) were performed by two different valves installed in series and operated in a definite sequence. IndiTech Intermittent Blowdown Valve carries out both these functions in sequence i.e. blowdown in open position and sealing in closed position. This is achieved by providing a multi-step throttling plug, which splits the total pressure drop across each step. The sealing area is separate from the throttling area, which reduces erosion and provides leak tightness even after prolonged usage.