Glossary and index of fluid power principles and components

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

L

LAG
Preferred engineering term for delay in response (usually in degrees).

LAMINAR FLOW
A condition of flow in a passage that is typified by slow movement of fluid in a relatively straight path along the centerline of a passage. See TURBULENT FLOW.

LEVEL TRANSMITTER
An electro-mechanical device which senses the level of fluid in a chamber and produces an analog signal that corresponds with the change of state in the chamber. See LEVEL SWITCH.

LEVEL SWITCH
An electro-mechanical device which senses the level of fluid in a chamber and opens or closes a digital switch to indicate a change of state. See LEVEL TRANSMITTER.

LEVERAGE
A gain in output force over input force by sacrificing the distance moved. Mechanical advantage or force multiplication.

LIFT
The measure of the capability of a pump to raise fluid from a lower to higher level at its inlet port without damage to the pump. Normally expressed in feet of water.

LINE
A connection between components, a passage for fluid or gas transfer. See PIPE, and TUBE and HOSE.

LINEAR ACTUATOR
A device for converting hydraulic energy into linear motion, i.e. a cylinder or ram.

LINEAR VARIABLE TRANSFORMER (LVT)
An electro-mechanical linear device that produces an analog signal in proportion to the difference in velocity between a magnet and a separate fixed coil.

LINEAR VARIABLE DIFFERENTIAL TRANSFORMER (LVDT)
An electro-mechanical linear device that produces an analog signal in proportion to the difference in distance between a magnet and separate fixed coil.

LINEARITY (SERVOVALVE)
The degree of straightness of the hysteresis plot.

LIQUID LEVEL GAUGE
Gauge to visually indicate the fluid level in a reservoir or tank.

LITER
A metric measure of volume. One (1) liter = 0.2642 gallons.

LOGIC CIRCUIT
A digital circuit (also called a gate) that has binary inputs and outputs and is capable of performing a decision making function.

LOOP INSTALLATION
The assembly is installed in a loop or “U” shape and is most often used when frequent and/or large amounts of motion are involved.

LUBRICATOR
A mechanical device which is used to inject drops or mist of oil into an air line for lubrication purposes.