Glossary and index of fluid power principles and components T
TACHOMETER
A digital or analog device that produces a pulse train of electrical signals that is proportional to its rotational speed.
TANK
See RESERVOIR.
TEMPERATURE SWITCH
A digital device that opens or closes a switch when the internal temperature changes state to a preset temperature limit.
THERMOCOUPLE
A precision resistive element that changes resistance in proportion to the temperature of the element. May be used, therefore, with proper DC electrical voltage to indicate temperature on a voltmeter style indicator.
THREE WAY
A term used to describe a valve that has three ports, normally a pressure (inlet) port, a normally closed (n.c.) port and a normally open (n.o.) port. Used to block or open a common flow passage.
THREE WAY VALVE, PROPORTIONAL CONTROL AND DIRECT OPERATED
A valve having a three way functional capability that may be proportionately actuated by a solenoid to control the operating spool in infinite resolution. Movement of the spool from extreme end to extreme rod completely reverses the flow paths of the ports. See THREE WAY.
THREE WAY VALVE, MANUALLY AND DIRECT OPERATED
A valve having a three way functional capability that may be manually activated to directly control the operating spool. Movement of the spool from extreme end to extreme end reverses the flow paths of the ports. See THREE WAY.
THREE WAY VALVE, SOLENOID AND PILOT OPERATED
A valve having a three way functional capability that may be solenoid activated to directly control the operating spool which then controls a secondary, larger spool. Movement of the secondary spool from extreme end to extreme end reverses the flow paths of ports. See THREE WAY.
THREE WAY VALVE, SOLENOID AND DIRECT OPERATED
A valve having a three way functional capability that may be solenoid activated to directly control the operating spool. Movement of the spool from extreme end to extreme end reverses the flow paths of the ports. See THREE WAY.
THROTTLE
To permit passing of a restricted flow. May control flow rate or create a deliberate pressure drop.
TIE ROD
A metal rod that is used to prevent two or more components from separating. Normally used to restrain the end plates of cylinders against the cylinder tube.
TORQUE
The measure of force applied to a lever arm. Normally expressed in lb.-ft. (pound-feet) or lb.-in. (pound-inch).
TORQUE CONVERTER
A rotary fluid coupling that is capable of multiplying torque.
TORQUE MOTOR
A coil of wire and bobbin assembly used in a servo valve that causes the internal mechanism of the servo valve to be offset when current passes through the coil.
TRANSDUCER
An analog device which produces a change in signal level during state changes. Normally used for high speed control systems.
TRANSFER FUNCTION
A mathematical expression of the relationship between the outgoing and incoming signals of a process or control element.
TRANSFORMER
A device that transfers AC energy from one circuit to another without electrical contact between the two circuits.
TRANSMITTER
An analog device which produces a change in signal level during state changes. Normally used for indication systems.
TUBE
A term used to describe a passage for fluid in a hydraulic system. Normally specified by outside diameter, wall thickness, material type and material strength.
TURBINE
A rotary device that is actuated by the impact of a moving fluid against blades or vanes.
TURBULENT FLOW
A condition of flow in a passage that is typified by rapid movement of fluid in a passage, where the fluid is churning and bouncing off the passage walls. See LAMINAR FLOW.
TWIST
1) The turns about the axis, per unit of length of a fiber, roving yarn, cord, etc. Twist is usually expressed as turns per inch. 2) The turn about the axis of a hose subjected to internal pressure.
TWO WAY
A term used to describe a valve that has two ports, normally a pressure (inlet) port and an outlet port. Used to open or close a flow passage. May be configured as normally closed (n.c.) Or normally open (n.o.).
TWO WAY VALVE, SOLENOID AND PILOT OPERATED
A valve having a two way functional capability that may be solenoid activated to directly control the operating spool which then controls a secondary, larger spool. Movement of the secondary spool from extreme end to extreme end opens or closes the flow paths of the ports. See TWO WAY.
TWO WAY VALVE, SOLENOID AND DIRECT OPERATED
A valve having a two way functional capability that may be solenoid activated to directly control the operating spool. Movement of the spool from extreme end to extreme end opens or closed the flow paths of the ports. See TWO WAY.
TWO WAY VALVE, MANUALLY AND DIRECTOPERATED
A valve having two way functional capability that may be manually activated to directly control the operating spool. Movement of the spool from extreme end to extreme end opens or closed the flow paths of the ports. See TWO WAY.