Glossary of Power Engineering Terms
I
| Term | Definition |
|---|---|
| IMPELLER |
The rotating element of a pump used to transfer mechanical energy from the pump to velocity energy in the water. |
| IMPELLER WEAR RING |
A ring attached to the impeller designed to absorb wear instead of the impeller. Also provides a seal between high and low-pressure areas of the pump. |
| IMPINGEMENT |
A situation where the flame in a boiler touches or contacts the tubes or other metal surfaces. This leads to erosion of the heating surfaces. |
| IMPROPER FRACTION |
A common fraction with the numerator equal to or greater than the denominator. (i.e. 4/3). |
| IMPULSE TURBINE |
A turbine that uses impulse action to change heat energy in the steam to mechanical energy. |
| INBOARD BEARING |
The bearing closest to the impeller of an end-suction pump |
| INCANDESCENCE |
The emission of light energy from a body as a result of raising it to a high temperature. |
| INCINERATION |
The process of controlled burning to reduce combustible wastes to a non-combustible residue, carbon dioxide, and other gases. |
| INCINERATOR |
A combustion chamber used to efficiently burn waste products. Also, in a gas processing plant, used to burn waste gases from the sulphur plant. |
| INCLUSION |
Impurities enclosed within the filler material of a weld. |
| INCOMPLETE COMBUSTION |
Combustion that is not complete; the products of combustion still contain combustible material. |
| INDIRECT SYSTEM |
A refrigeration system in which a secondary solution, i.e. Brine, is circulated into the air or substance to be cooled, i.e. The secondary solution flows to and from the evaporator to release the heat absorbed from the air or substance being cooled. |
| INDUCED DRAFT |
A boiler draft system where a fan at the boiler uptake is used to draw the flue gases from the boiler furnace. |
| INFILTRATION AIR |
Air that flows into a building when exterior doors are open or when air leaks in through cracks in the building envelope. |
| INFLOW |
Water discharged into a sewer system and service connections from sources other than regular connections. This includes flow from yard drains, foundation drains and around manhole covers. Inflow differs from infiltration in that it is a direct discharge into the sewer rather than a leak in the sewer itself. |
| INPUT |
Information put into a communication system for transmission or into a computer system for processing; a position, terminal, or station at which input enters a system. |
| INPUT DEVICES |
The devices at which or with the help of which, the information enters the computer system. |
| INSIDE SEAL |
A mechanical seal whose sealing faces are placed inside of the stuffing box. |
| INSULATOR |
A substance that is a poor conductor of electricity as a consequence of a lack of free electrons. |
| INTERCOOLED CYCLE |
A gas turbine employing two compressors, the compressed air from the first compressor is cooled before being discharged into a second compressor. |
| INTERCOOLERS |
Heat exchangers that remove the heat of compression from air or gas between consecutive stages of multistage compressors. |
| INTERCOOLING |
Removal of heat from compressed gas between compression stages. |
| INTERLOCKS |
Automatic safety switches incorporated into the boiler burner management system which will shut down the combustion process if an unsafe boiler condition exists. |
| INTERNAL COMBUSTION ENGINES |
An engine in which the combustion process occurs within the engine itself. |
| INTERNAL FURNACE |
Furnace that is located within the boiler and is surrounded by water. |
| INTERRUPTED PILOT |
An automatically ignited pilot used to ignite the boiler main flame but is then automatically shut off while the boiler is running. |
| INVERT |
To switch or reverse the numerator and the denominator, i.e., the invert of 5/9 would be 9/5. |
| ION |
A particle, atom, or group of atoms carrying either a positive or negative charge, i.e. Na+2, SO4-2, PO4–3. |
| ION EXCHANGE |
A process in which undesirable ions in water are exchanged with more desirable ions. |
| IONIZATION |
The process of adding electrons to, or removing electrons from, atoms or molecules, thereby creating ions. High temperatures, electrically discharges, and nuclear radiation can cause ionization. |