blowoff

Blowoff, sometimes written as blow-off or blowoff valve in specific contexts, is a term used in engineering and industry to describe a controlled release of gas, steam, or liquid from a pressurized or closed system. The exact meaning depends on context, but the common idea is to prevent overpressure, purge contaminants, or remove unwanted material.

In safety and process equipment, a blow-off valve or vent is installed to discharge excess pressure. In steam boilers and chemical reactors, automatic relief devices vent to atmosphere or to a downstream scrubber. Operators may also perform manual blow-off operations to drain a section of pipe for maintenance. A related term, blowdown, refers to the periodic removal of water from a boiler or process vessel to control impurities; the discharged liquid is sometimes called blowoff water.

In boiler management, continuous blowdown continuously removes small amounts of water to limit dissolved solids; intermittent (manual) blowdown provides periodic purge of accumulated sludge or scale. Proper blowoff procedures, filtration, and disposal are important to prevent environmental release or equipment damage.

In manufacturing and maintenance, blow-off devices use compressed air to clear debris from parts or surfaces. These tools require careful control of pressure, nozzle design, and personal protective equipment to prevent injury from high-velocity air or flying particles.

In automotive engineering, a blow-off valve releases boost pressure in turbocharged engines when the throttle is released, reducing compressor surge. Some devices vent to the atmosphere producing a characteristic sound, while others recirculate air back into the intake system.