4:1

A safety factor of a fluid component indicating the burst pressure is four times the working pressure.

5:1

A safety factor of a fluid component indicating the burst pressure is five times the working pressure.

5252

A constant used for determing torque when torque is measured in poundfeet.

6:1

A safety factor of a fluid component indicating the burst pressure is six times the working pressure.

63025

A constant used for determing torque when torque is measured in poundinches.

actuator

A component such as a cylinder, motor, or rotary device that directly helps convert fluid energy into mechanical energy.

annular

Ringshaped. The annular area of a piston is the area on the rod side of a cylinder not occupied by the rod.

area

The amount of space, or number of square units, inside a closed figure.

atmospheric pressure

The weight of the atmosphere. Atmospheric pressure refers to the amount of pressure exerted by the air.

bore

The interior diameter of a cylinder.

bore diameter

The size of a cylinder's piston housing measured from two points located directly opposite each other.

burst pressure

The pressure rating that indicates the pressure at which a conductor will fail.

cap end

The side of the piston that is opposite the rod. The cap end is also called the blind end.

conversion factor

A mathematical constant used to convert one unit of measurement into another.

direct relationship

An association in which the value of one variable increases while the value of the other variable increases as well, and vice versa. A direct relationship is also called a positive relationship.

directly proportional

A constant relationship between two values. If value A increases, value B also increases. If value A decreases, then value B also decreases.

displacement

A fluid power variable that indicates how much fluid is moved by a hydraulic pump in one cycle. Displacement is measured in cubic inches per revolution or cubic centimeters per revolution.

efficiency

The amount of power output by a fluid power system compared to the amount of power input.

extension

The movement of a singleacting cylinder characterized by fluid pushing on the piston and moving the rod outside of the cylinder housing. In a doubleacting cylinder, extension occurs on each stroke and alternates between ends of the cylinder.

fivetoone

A safety factor that indicates a burst pressure that is 5 times the working pressure.

flow rate

A fluid power variable that describes how much fluid is being moved and how much work is being performed. Flow rate is usually measured in gallons per minute (gpm) or liters per minute (lpm).

force

The push or pull that gives energy to an object.

fourtoone

A safety factor that indicates a burst pressure that is 4 times the working pressure.

gauge pressure

Psig. The pressure of a system measured by a gauge, above atmospheric pressure.

horsepower

A unit of power used to describe the strength of a fluid component. One horsepower equals 746 watts.

hydraulic motor

A device that converts the energy from liquid flow into mechanical motion. A hydraulic motor is a type of fluid motor that is capable of continuous mechanical motion.

hydraulic pump

A mechanical device used to move liquids. The hydraulic pump introduces flow and pressure into the system.

incompressible

Incapable of being compressed by pressure and maintaining a relatively fixed volume. Gases are compressible, while liquids are relatively incompressible.

inverse relationship

An association in which the value of one variable increases while the value of the other variable decreases, and vice versa. An inverse relationship is also called a negative relationship.

inversely proportional

A constant relationship between two values. If value A increases, then value B decreases. If value A decreases, then value B increases.

load

The amount of force or pressure placed on a component or system.

logic

The unique configuration of a fluid circuit that involves placing components to perform work.

Pascal's Law

A hydrostatic principle that states when pressure is applied to a contained fluid, the force is transmitted equally in all directions.

pi

A special constant value that relates the diameter of a circle to its circumference. Pi is roughly 3.14 and is used to find the circumference and area of a circle.

pressure

The amount of force applied upon an object. Pressure is calculated by dividing force by an area.

prime mover

The component of a hydraulic or pneumatic system that powers the main pump or compressor. Common prime movers for hydraulic systems include electric or dieselpowered motors.

psig

The pressure of a system measured by a gauge, above atmospheric pressure.

retraction

The movement of a singleacting cylinder characterized by fluid exiting the cylinder and the rod moving into the cylinder housing. In a doubleacting cylinder, retraction occurs on each stroke and alternates between ends of the cylinder.

rod end

The side of the piston that is attached to the rod.

RPM

Revolutions per minute. The speed of a fluid component may be measured by how many revolutions the component completes in one minute.

safety factor

The ratio of burst strength to working strength. A conductor with a safety factor of 5:1 has a burst pressure that is 5 times the working pressure.

schedule 160

A common pipe designation that indicates the thickness of pipe wall and how much pressure a pipe can withstand. Other schedules include 40 and 80, among others.

sixtoone

A safety factor that indicates a burst pressure that is 6 times the working pressure.

temperature

A measurement of the thermal energy in a substance. Molecular activity determines temperature.

tensile strength

The maximum stress, or tension, a material can endure before it breaks. Tensile strength is usually expressed in pounds per square inch.

torque

A force that produces rotation. Torque is measured in poundfeet in the English system and Newtonmeters in the metric system.

vacuum

The state of negative pressure. A hydraulic pump works by creating a vacuum in the closed hydraulic system.

volume

The amount of threedimensional space occupied by an object.

working pressure

The pressure rating that indicates the maximum pressure a conductor should experience in service. Working pressure is often called maximum allowable working pressure (MAWP).
