IEC 60534-2-4 pdf download

IEC 60534-2-4 pdf download Industrial-process control valves – Part 2-4: Flow capacity – Inherent flow characteristics and rangeability
1 Scope
This part of IEC 60534 applies to all types of industrial-process control valves. It defines how to state typical control valve inherent flow characteristics and inherent rangeabilities. It also defines how to establish criteria for adherence to manufacturer-stated flow characteristics.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition or the referenced document (including any amendments) applies.
IEC 60534-1 :2005, Industrial-process control valves – Part 1: Control valve terminology and general considerations
IEC 60534-2-3, Industrial-process control valves – Part 2-3: Flow capacity – Test procedures
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60534-1 and the following apply.
3.1
flow coefficient
(see IEC 60534-1 , 4.6)
3.2
rated flow coefficient
(see IEC 60534-1 , 4.6.3)
3.3
relative flow coefficient ( Φ )
Φ 0 is the relative flow coefficient at 0 % relative travel
[IEC 60534-1 , 4.9 modified]
3.4
travel
(see IEC 60534-1 , 4.5.2)
3.5
rated travel
(see IEC 60534-1 , 4.5.3)
3.6
relative travel (h)
(see IEC 60534-1 , 4.5.4)
3.7
nominal slope
slope of the best fit line
for an ideal inherent linear flow characteristic, the nominal slope is: m
3.8
inherent flow characteristic
(see IEC 60534-1 , 4.9)
3.8.1
ideal inherent linear flow characteristic
(see IEC 60534-1 , 4.9.1 )
3.8.2
ideal inherent equal percentage flow characteristic
(see IEC 60534-1 , 4.9.2)
3.9
inherent rangeability
ratio of the largest flow coefficient ( Φ max ) to the smallest flow coefficient ( Φ min ) within which the deviation from the stated inherent flow characteristic does not exceed the allowable
deviation stated in Clause 7
[IEC 60534-1 , 4.1 1 modified]
4 Symbols
Table 1 gives an overview of the symbols used in this standard.