Stationary Engineering

Cards · 55

Stationary Engineer

A professional who operates, maintains, and manages stationary machinery and mechanical systems such as boilers, chillers, and generators.

Boiler

A closed vessel in which water or other fluid is heated under pressure to generate steam or hot water.

Fire-tube Boiler

A boiler in which hot combustion gases pass through tubes submerged in water.

Water-tube Boiler

A boiler in which water circulates inside tubes heated externally by combustion gases, suited for high pressures.

Sensible Heat

Heat energy that causes a measurable change in temperature without changing the substance's phase.

Latent Heat

Heat absorbed or released during a phase change at a constant temperature.

Latent Heat of Vaporization

The amount of heat required to convert a unit mass of liquid into vapor without a change in temperature.

Saturated Steam

Steam in thermodynamic equilibrium with liquid water at its boiling point for a given pressure.

Superheated Steam

Steam heated to a temperature above its saturation point at a given pressure, containing no moisture.

Boiler Safety Valve

An automatic pressure-relieving safety device actuated by static pressure to prevent overpressurization.

Safety Relief Valve

A pressure relief valve designed for liquid service, opening proportionally as pressure increases.

Low Water Fuel Cutoff (LWCO)

A safety device that shuts off fuel flow to the burner if the boiler water level drops below a safe limit.

Gauge Glass

A transparent tube attached to a boiler water column that displays the current water level.

Water Column

A vertical chamber attached to the boiler shell that dampens water fluctuations for accurate level measurement.

Try Cocks

Small valves mounted on the water column used to manually verify the boiler's water level.

Surface Blowdown

Continuous discharge of water from near the boiler surface to remove dissolved solids and prevent foaming.

Bottom Blowdown

Intermittent discharge from the lowest point of a boiler to purge accumulated sludge, sediment, and heavy scale.

Deaerator

A mechanical device that heats feedwater to remove dissolved non-condensable gases, specifically oxygen and carbon dioxide.

Feedwater Heater

A heat exchanger that preheats water entering the boiler using extraction steam to improve thermal efficiency.

Economizer

A heat recovery device that extracts residual heat from flue gases to preheat boiler feedwater.

Steam Trap

An automatic valve that discharges condensed steam and non-condensable gases without allowing live steam to escape.

Thermodynamic Steam Trap

A steam trap that operates on the difference in fluid dynamics and velocity between steam and condensate.

Inverted Bucket Trap

A mechanical steam trap that uses a buoyant inverted bucket to open and close the condensate discharge valve.

Thermostatic Steam Trap

A steam trap actuated by temperature differences between hotter steam and cooler condensate.

Water Hammer

A violent hydraulic shock wave caused by rapidly stopping fluid flow or steam condensing abruptly in pipes.

Boiler Scale

A mineral coating deposited on heat transfer surfaces by dissolved calcium and magnesium salts in untreated water.

Boiler Priming

The carryover of significant slugs of liquid water into the steam line alongside steam discharge.

Boiler Foaming

The formation of persistent foam bubbles on the water surface caused by high dissolved solids or oils.

Combustion

A rapid chemical reaction between fuel and oxygen that releases heat and light energy.

Stoichiometric Combustion

The theoretical ideal burning process where all fuel is consumed with no excess oxygen remaining.

Excess Air

Air supplied beyond the theoretical stoichiometric requirement to ensure complete fuel combustion.

Draft

The difference in pressure between the combustion chamber or flues and the surrounding atmosphere.

Forced Draft Fan

A fan that pushes air under positive pressure into the combustion chamber.

Induced Draft Fan

A fan that draws flue gases out of the boiler and pushes them into the chimney under negative pressure.

Flame Safeguard System

A control system that monitors the burner flame and shuts off fuel supply immediately upon flame failure.

Cad Cell

A photo-resistive flame detector sensitive to visible light, commonly used in oil burners.

Flame Rod

A sensor that detects flame presence by utilizing the electrical conductivity and rectification of ionized gas in a flame.

Refrigeration Cycle

A thermodynamic cycle that moves heat from a low-temperature reservoir to a high-temperature sink using a working fluid.

Compressor

A mechanical device in a refrigeration loop that raises the pressure and temperature of refrigerant vapor.

Condenser (Refrigeration)

A heat exchanger where high-pressure vapor refrigerant rejects heat to air or water and condenses into a liquid.

Expansion Valve (TXV)

A throttling device that meters liquid refrigerant into the evaporator while drastically reducing its pressure.

Evaporator

A heat exchanger where low-pressure liquid refrigerant absorbs heat from the surrounding medium and boils into vapor.

Subcooling

The temperature difference between a liquid refrigerant and its saturation temperature at a given pressure.

Superheat (Refrigeration)

The temperature increase of refrigerant vapor above its boiling point at a given saturation pressure.

Chiller

A central refrigeration machine that removes heat from water, which is then circulated to cool building air or equipment.

Cooling Tower

A heat rejection device that cools condenser water by evaporating a small portion into an atmospheric air stream.

Centrifugal Pump

A machine that uses a rotating impeller to impart kinetic energy and increase the pressure and flow of a liquid.

Cavitation

The formation and violent collapse of vapor bubbles in a liquid due to localized pressure drops below vapor pressure.

Net Positive Suction Head (NPSH)

The total suction head available at the pump suction nozzle above the vapor pressure of the liquid pumped.

Mechanical Seal

A shaft-sealing device that prevents fluid leakage between rotating shafts and stationary pump bodies.

Air Handling Unit (AHU)

A centralized device used to condition and circulate air as part of a heating, ventilating, and air-conditioning system.

Psychrometrics

The study of the thermodynamic properties of moist air and its physical behavior at atmospheric pressures.

Wet-bulb Temperature

The lowest temperature that can be achieved purely by the evaporative cooling of a water-wetted surface.

Relative Humidity

The ratio of water vapor partial pressure in air to the equilibrium vapor pressure at that temperature, as a percentage.

Lockout/Tagout (LOTO)

A critical safety procedure ensuring dangerous machinery is properly de-energized and unable to restart during maintenance.