ISO 5598:2020 流体動力システムとコンポーネント — 語彙 | ページ 2

3.2.792

valve hydraulic lock

undesirable locking of a piston or spool due to pressure (3.2.560) imbalance, which forces the piston or spool sideways, causing sufficient friction to resist axial movement

3.2.793

valve manifold

valve island

<pneumatic> type of manifold assembly (3.2.433) or stacked valve assembly (3.2.713) that can include electrical connections

3.2.794

valve main port

port (3.2.551) in a valve (3.2.790) that is either connected to another port or blocked upon actuation of a control mechanism (3.2.139)

Note 1 to entry: Pilot ports (3.2.528) , drain ports (3.2.231) and other auxiliary ports are not valve main ports.

3.2.795

valve port/position designation

method of numerical designation for directional control valves (3.2.217) , using two numbers separated by an oblique stroke, e.g. 3/2, 5/3

Note 1 to entry: The first number indicates the number of main ports that the valve (3.2.790) has and the second number indicates the number of specific positions that its valving element (3.2.796) is capable of adopting.

Note 2 to entry: Deprecated terms such as “three-way”, “four-way valves” should not be used.

3.2.796

valving element

internal part of a valve (3.2.790) that, by its movement, provides the basic function of directional control, pressure (3.2.560) control or flow rate (3.2.303) control

3.2.797

valving element positions

positions of the valving element (3.2.796) that control the basic function

3.2.798

vane motor

motor (3.2.455) in which shaft rotation is achieved by means of fluid (3.2.316) pressure (3.2.560) acting on a set of radial vanes

3.2.799

vane pump

<hydraulic> hydraulic pump (3.2.370) in which fluid (3.2.316) is displaced by a set of radial sliding vanes

3.2.800

vapour

gas that is at a temperature below its critical temperature and that, therefore, can be liquefied by isothermal compression

3.2.801

vapour contamination

contamination (3.2.133) in vapour (3.2.800) form expressed in terms of mass per mass at the specified operating temperature

3.2.802

vent

passage to a reference pressure (3.2.628) , normally the ambient pressure (3.2.560)

3.2.803

viscosity

resistance of a fluid to flow (3.2.294) resulting from internal friction

3.2.804

viscosity index

empirical measure of the viscosity (3.2.803) /temperature characteristics of a fluid

Note 1 to entry: When the variation in viscosity is small, the index is high.

3.2.805

viscosity index improver

chemical compound added to a fluid to modify its viscosity (3.2.803) /temperature relationship

3.2.806

visual particle counting

measurement of solid particle (3.2.517) contamination (3.2.133) in a fluid (3.2.316) by optical means

Note 1 to entry: See ISO 4407.

3.2.807

water content

quantity of water contained in a fluid

3.2.808

water hammer

oil-hammer

<hydraulic> oscillating pressure (3.2.560) pulse phenomenon generated by a rapid decrease in flow rate (3.2.303) acting against a compressible energy store

3.2.809

water polymer solution

polyglycol solution

<hydraulic> fire-resistant hydraulic fluid (3.2.364) in which the major constituents are water and one or more glycols or polyglycols

3.2.810

water trap

<pneumatic> component (3.2.115) fitted to a system to collect moisture

3.2.811

water-in-oil emulsion

invert emulsion

<hydraulic> dispersion of finely divided water droplets in a continuous phase of mineral oil (3.2.451) with special emulsifiers, stabilizers and inhibitors (3.2.393)

Note 1 to entry: Changes in water content (3.2.807) can reduce the stability and/or fire resistance of the emulsion.

3.2.812

weight-loaded accumulator

<hydraulic> hydraulic accumulator (3.2.361) in which the fluid (3.2.316) is subjected to pressure (3.2.560) by gravitational force acting upon a weight-loaded piston

3.2.813

weld-on nipple

spud coupling

part of a connector (3.2.127) that is permanently attached to piping (3.2.531) by welding or brazing

3.2.814

wiper ring

scraper

device used to prevent ingress of contaminants (3.2.129) on reciprocating rods

3.2.815

working line

flow path (3.2.302) through which fluid (3.2.316) is transmitted to an actuator (3.2.11)

3.2.816

working port

component (3.2.115) port (3.2.551) for use with a working line (3.2.815)

3.2.817

working pressure range

range of pressures (3.2.560) between the limits within which a system or sub-system (3.2.737) can be operated in steady-state operating conditions (3.2.726)

Note 1 to entry: See Figure 20.

3.2.818

Y connector