Article Index

Igniter- A device for igniting a fuel mixture that provides proven ignition energy required to immediately light off the main burner

Ignition- The initiation of combustion.

Ignition temperature- The lowest temperature at which a combustible substance when heated takes fire in air and continues to burn.

Incomplete combustion- Will occur when there is not enough oxygen to allow the fuel to react completely to produce carbon dioxide and water.

Induced draft fan- Is used on the exhaust side of boiler pulling air through the boiler to exhaust hot gases from the heat absorbing equipment.

Inhibitor- A substance that slows down or prevents a particular chemical reaction or other process, or that reduces the activity of a particular reactant, catalyst, or enzyme. An example in boiler work is the use of an inhibitor, when using acid to remove scale, to prevent the acid from attacking the boiler metal.

Injector- Utilizes a steam jet to deliver feed water into a boiler.

Input rating- The fuel burning capacity of a burner at sea level in Btu per hour as specified by the manufacturer.

Insulation- Material used to insulate something to reduce heat losses.

Interlock- A device to prove the physical state of a required condition, and to furnish that proof to the primary safety control circuit.

Intermittent blowdown- Intermittent Blowdown valves are designed to operate at predetermined intervals by releasing water & accumulated sludge periodically through a blowdown tap near the bottom of the boiler.

Intermittent firing- Cyclic firing whereby fuel and air are burned in a furnace for frequent short periods.

Internal treatment- The treatment of boiler water by introducing chemicals directly into the boiler.

Intermittent ignition- An igniter which burns during light off and while the main burner is firing and which is shut off with the main burner.

Internally fired boiler- A firetube boiler whose fire box or furnace is inside the boiler and surrounded by water.

Ion- An atom or molecule with a net electric charge due to the loss or gain of one or more electrons.

Ion exchange-The exchange of ions of the same charge between an insoluble solid and a solution in contact with it, used in water-softening and other purification and separation processes.

Lagging- Material providing heat insulation for a boiler, pipes, etc.

Leakage- Gradual loss of fluid from which enters or leaves through the enclosure of air or gas passages.

Limit control- A device that has electrical settings to switch off at predetermined pressures or temperatures. Also known as an interlock. See interlock.

Lining- High temperature insulation known as refractory; this material insulates the area in furnace that is exposed to the burner flame.

Live steam- Is steam under pressure, obtained by heating water in a boiler. The steam is used to operate stationary or moving equipment.

Load- Amount of output required and weight carried.

Load factor- Load Factor is defined as the ratio of average demand to maximum demand during a given period.

Low draft switch- A control to limit the burner action if the draft is too low. Generally used with mechanical draft.