ISA RP75.23

This recommended practice is intended for control valves used inthe control of process fluids and is not intended to apply to fluidpower components. The reader and user should be familiar with fluidmechanics fundamentals and ISA standards ANSI/ISA S75.01 andANSI/ISA S75.02 on valve sizing and testing. Definitions of termsin this document are intended for general understanding; morerigorous definitions are found in the references.

Noise measurement and prediction methods are beyond the currentscope of this document. Methods of liquid flow noise measurementand prediction may be found in standards of the InternationalElectrotechnical Commission, CEI/IEC documents 534-8-2 and 534-8-4.The relationship between cavitation parameters used in thisrecommended practice and those of the IEC documents is discussed inAnnex B.

Purpose

Cavitation as an applied science has not evolved to the highlyrefined level of that supporting the more traditional control valvesizing calculations. However, there is a great need by users andmanufacturers alike for practical information in this area. Thepurpose of this document is to supply that information, and to thatend it is necessarily broad in scope. It embodies severalobjectives:

a) to provide educational material in a background section thatcondenses the literature and educates the reader instate-of-the-art valve cavitation knowledge and practice;

b) to establish a basis for communication by defining cavitationparameters and nomenclature;

c) to propose methods for evaluating the cavitationcharacteristics of individual control valves through testingprocedures and application experience; and

d) to offer guidelines for selecting control valves for givenapplications.

ISA Subcommittee SP75.16 recognizes that the science ofcavitation is in its infancy in terms of defining the behavior ofcavitation in complex valve geometry. The final objective of thisrecommended practice is to promote additional research and testing.Subsequently, this practice can serve as a starting point for thoseseeking to advance the state of the art.

Edition:

95

Published:

06/02/1995

Number of Pages:

60

File Size:

1 file , 530 KB