Pipe Elements No. 1 - Mechanical Engineering Review

Comprehensive vocabulary flashcards covering power plant elements, thermodynamics, refrigeration codes, standards, and equipment.

Rotary Dryer

The most common dryer used, consisting of a rotating cylinder inside which materials flow while getting in contact with hot gas.

Relative Humidity

The ratio of the mass of water vapor present in air to the mass of water vapor if the air were saturated at the same conditions.

Cold Skin Pain Threshold

The skin temperature at which the hands feel painfully cold, specifically $10\,^{\circ}\text{C}$.

Steam Jet Cooling Refrigerant

Water, which serves as the working refrigerant in a steam jet refrigeration system.

Total Heat of Air

A thermodynamic property of moist air that is a direct function of the wet-bulb (WB) temperature.

Freon-12 Boiling Point

The saturation temperature of Freon-12 at standard atmospheric pressure, equal to $21\,^{\circ}\text{F}$.

Absorber

The component of an absorption refrigeration system in which the refrigerant-absorbent solution is cooled by cooling water as it absorbs refrigerant vapor.

Cascade Refrigeration Cycle

A multi-stage refrigeration cycle connected in series, often used in industrial processes where objects must be cooled to temperatures below $-46\,^{\circ}\text{C}$.

Capillary Tube

A fixed-restriction refrigerant expansion device commonly used in household refrigeration, designed to maintain a pressure difference while the compressor is operating.

Acoustic Leak Detector

A modern detection device used to locate compressed air leaks in air compressor piping systems.

Impulse Turbine

A type of hydraulic turbine that operates with a specific speed below $5$.

Propeller Turbine

A high-discharge, axial-flow type of hydraulic turbine designed for low-head applications.

Jet Deflector

A mechanical device used in impulse turbines to divert the water jet away from the runner buckets to minimize speed rise during sudden load rejection.

Unit Speed

The theoretical rotational speed of a hydraulic turbine when operating under an effective head of one meter.

Cohesion

The fluid property that refers to the intermolecular attraction by which separate particles of the same fluid are held together.

Binary Geothermal Plant

A type of geothermal power plant utilized when extracted underground geothermal fluid contains heavy brine.

Safety Valve

The most important safety relief device mounted on a power boiler, which must be removed during hydrostatic pressure testing.

Exothermic Reaction

A chemical reaction during which chemical potential energy is released to the surroundings in the form of heat.

Blends

Refrigerants consisting of mixtures of two or more different chemical compounds, often individually used as refrigerants in other applications.

Companion Valve

Pairs of mating stop valves that allow sections of a piping system to be joined before opening or separated after closing them.

Corridor

An enclosed architectural passageway that limits travel to a single path.

Immediately Dangerous to Life or Health (IDLH)

The maximum airborne concentration from which unprotected persons can escape within $30\,\text{min}$ without experiencing escape-impairing symptoms or irreversible health effects.

Internal Gross Volume

The total internal volume calculated strictly from inside dimensions of a container without deducting the volume displaced by internal parts.

Means of Egress

A continuous and unobstructed path of vertical and horizontal travel from any point in a building or structure to a public way.

Pressure-Imposing Element

Any mechanical device or portion of refrigeration equipment utilized to increase the refrigerant pressure.

Pumpdown Charge

The quantity of liquid refrigerant safely stored in a designated component or receiver of a refrigeration system for operational, service, or standby purposes.

Secondary Refrigerant

A heat-transfer liquid that conveys heat without a change of state, having no flash point or a flash point above $150\,^{\circ}\text{F}$ as tested under ASTM standards.

Three-Way Valve

A service manifold valve for dual pressure-relief devices that isolates one relief device for maintenance while maintaining the other in active operation at all times.

Unprotected Tubing

Refrigerant tubing that is unenclosed and thus susceptible to crushing, abrasion, puncture, or physical damage following installation.

Zeotropic

Refrigerant blends made of multiple components with different volatilities that exhibit temperature glide and change composition during constant-pressure phase change.

Institutional Occupancy

A premise classification where occupants cannot readily evacuate without physical assistance from others due to being disabled, debilitated, or confined.

Indirect Open Spray System

A refrigeration cooling design where an intermediate secondary coolant comes into direct, unconfined contact with the conditioned air or substance.

R-744

The standardized ASHRAE refrigerant designation for carbon dioxide ($\text{CO}_2$).

R-1150

The standardized ASHRAE hydrocarbon refrigerant designation for ethene (ethylene).

R-40

The standardized ASHRAE chemical refrigerant designation for chloromethane (methyl chloride).

Plenums

Continuous compartments or spaces above suspended ceilings that serve as part of the return air distribution system in buildings.

Drier Loop

A pipe coil piped in series with an evaporator designed to evaporate remaining droplets and prevent liquid refrigerant from entering the compressor.

Desuperheating Coils

Finned or bare pipe coil surfaces added to remove sensible discharge superheat and increase total condenser capacity.

Liquid Subcooler

A heat-exchanging device used to subcool liquid refrigerant below its saturation temperature after leaving the condenser.

Evaporative Condenser

A hybrid condensing device that rejects heat by spraying recirculated water over coils while drawing air through, operating functionally like a cooling tower.

Miscibility

The property describing the mutual solubility and ability of compressor lubricating oil to mix completely with a refrigerant.

Electronic Leak Detector

An instrument that detects refrigerant gas leaks by sensing electric current variations produced when decomposed refrigerant is ionized between oppositely charged platinum electrodes.

Drain Cooler

A heat transfer section utilized when extracted turbine steam condensate undergoes subcooling prior to cascading or pumping.

Deaerator

An open feedwater heater that heats boiler feed water by direct contact while stripping away dissolved corrosive gases like $\text{O}_2$ and $\text{CO}_2$.

Closed Feedwater Heater

A shell-and-tube heat exchanger where feedwater flows inside pressurized tubes, allowing multiple heater stages to operate with only a single feedwater pump.