There are 51 entries in this glossary.
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Term Main definition

A hollow cylindrical trim element that is a guide to align the movement of a valve plug with a seat ring and also retains the seat ring in the valve body. Often the walls of the cage contain opening which determines the flow characteristics of the control valve.


Rate of flow through a valve under stated conditions.


A fastener having a head and whose shank is normally threaded throughout its entire length. Not used with a nut but rather engagement is made with a female thread in the piece to be joined.


A part made by pouring molten metal into a mold without any further forging or rolling.


The formation and subsequent collapse within a liquid of cavities or bubbles that contain vapor or gas or both. Cavitation originates from a local decrease in hydrostatic pressure in the liquid produced by motion of the liquid or of a solid boundary. The term cavitation should not be used to denote the damage or erosion of a solid surface that can be caused by it. This effect of cavitation is termed cavitation damage or cavitation erosion.

CBV (Control Ball Valve)

An automatic throttling valve controlling flow or pressure in a pipeline comprising a package involving a ball valve an actuator a positioner and controlling instruments.

CE Marking

The CE marking is a mandatory European marking for certain product groups placed on the European Economic Area (EEA) to indicate conformity with the essential health and safety requirements set out in European Directives. To permit the use of a CE mark on a product proof that the item meets the relevant requirements must be documented.


An independent body appointed by the purchaser to carry out a survey of the equipment and/or materials that they are buying. It is the responsibility of the supplier to provide the C.A. with information documents access to works and personnel to enable the survey to be carried out.

CFO (Computational Fluid Dynamics)

It is a branch of fluid mechanics that uses numerical methods and algorithms to analyze and solve problems involving fluid flows. The basis of almost all CFD problems are the NAVIER STOKES equations. Finite element method is the most used. The domain is divided into several little volumes in which the conservation equations are discretized and solved.


An overhead valve operated by a chain drive wheel instead of a handwheel.


A chain operated wheel attached to a manual actuator with a closed loop of chain to enable the operation of an overhead valve.


A ball or gate the shape of whose port has been altered to provide a specific throttling capability. One of the most common is the V-Port ball design.


A mechanical dynamic test that provides a measure of the energy required to break a material under impact loading. The test consists essentially of a hammer with a given amount of energy striking a notched specimen of fixed dimensions. The measured test values may be the energy absorbed the percentage shear fracture the lateral expansion opposite the notch or a combination thereof. It provides a relative measure of the toughness of steel or its resistance to shock or impact loads. Often required for low temperature applications where testing is done at the expected minimum service temperature. Test procedure is defined in ASTM A370.


A unidirectional valve which is opened by the fluid flow in one direction and which closes automatically when the flow stops or reverses direction.


The hinged closure element of a swing check valve.

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