BLOW-OFF VALVES

One of three valves mounted on a boiler or water column within the visible range of the gauge glass and used to check the water level.

1.A flat plate against which something rests or is pressed. 2. The rubber-covered roller of a typewriter against which paper is pressed when struck by the typebars. 2. A flat surface for exchanging heat in a boiler or heat exchanger which may have extended heat transfer surfaces.

A tube through which steam and water pass from an upper waterwall header to a drum.

The lowest water level in a boiler drum at which the burner may safely operate.

Furnace explosions caused by oil vapour and air present in furnace in explosive proportions. To a lesser extent a blowback is a furnace explosion. Prevention is by purging with air. Usually adequate purging is provided within the combustion control however makers timings should be strictly followed . N.B. This is particularly important with membrane wall boilers where the pressure wave is contained within a strong cell which if ruptured, has disastrous consequences.

The type of heater which consists of set of tubes for air flow. Tube are passing through flue gas flow and extended into tube plates The horizontal tube type air heater less susceptible to choking with soot than the vertical types sometimes found with older scotch boilers. To aid cleaning water washing was sometimes carried out to aid the sootblowers.

The amount of contaminants a filter will hold before an excessive pressure drop is caused. Some filters have bypass valves which open when a filter reaches its rated capacity.

Refers to the carryover which occurs in any boiler operating under the best conditions.

A tube in a boiler having the water and steam on the inside and heat applied to the outside.

A device for admitting feedwater to a boiler automatically on demand. Practically a constant water level should result.