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 Ultrasonic Test A non-destructive inspection procedure using high frequency sound waves to detect voids and imperfections throughout the thickness of metal parts. Techniques and procedures are covered in ASME V, Art. 4, Art. 5, and ASTM A388, A435 and A577. Unidirectional Valve Valve designed for blocking the flow in one direction only. Union Connection … Read more

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 Tee Piece A pipe or tubing fitting with a side outlet at right angles. Resembles a T. Tensile Strength The maximum amount of tensile stress (ultimate strength) that a material can withstand before failure or rupture occurs. It is the maximum stress developed in a material in a Tensile Test. Tensile Test A test … Read more

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 Safety Factor Is a factor applied to the nominal operating torque or thrust given by the valve manufacturer. Can be between 1.2 and 2.0 depending on application. Safety Relief Valve A quick-acting spring-loaded valve that opens (relieves) when the pressure exceeds the spring setting. It specifically opens proportionally with pressure increasing. Often installed on … Read more

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 Ra (Roughness: Arithmetic Average Deviation) It is the arithmetic average of the absolute values of the profile deviations from the mean line of the roughness profile. Statistically very stable repeatable parameter good for random type surface such as grinding. Not a good measure of sealed surfaces. Reduced Port (Bore) See Venturi Valve. Regulator A … Read more

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 QEV (Quick Exhaust Valve) A one-way valve connected directly to the actuator cylinder. Having a large exhaust port, it allows fast dumping of air from the cylinder directly to atmosphere. Qualification Test Additional testing requirements are performed on a product to determine whether or not the product conforms to all of the requirements of … Read more

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 Potentiometer The principle of its operation is that a voltage gradient is generated across a resistive element which has a variable pick off point connected to the valve stem. As the stem moves, the voltage changes across the potentiometer to provide an electrical output of the valve position. Power Operator Powered valve operators are … Read more