User Guide

F-24384-1 © Copyright 2006 TAC All Rights Reserved. 3
Normal Position of Valve Assembly
For a valve assembly (valve, linkage, and actuator) to have a normal (spring return) position,
the actuator must be of the spring return type. See Table-2 for the normal position of the
valve assemblies.
Table-2 Required Compatible Actuators/Linkages.
Flow Characteristics
All valves have modified equal percentage flow characteristics. That is, for equal increments
of valve stem stroke, the change in flow rate with respect to valve stroke may be expressed
as a constant percent of the flow rate at the time of the change. The change of flow rate with
respect to valve stroke is relatively small when the valve plug is near the valve seat and
relatively high when the valve plug is nearly wide open. See Figure-1 for typical modified
equal percentage flow characteristics of VB-7221 series valve bodies.
Figure-1 Typical Modified Equal Percentage Flow Characteristics.
Actuator Series Required Valve Linkage Normal Position
MA-5210, MA-5211, MA-5213 AV-7600
a
Stem Up
Normally Closed
MF-5413, MF-5513 AV-7600 & AV-601
MK-2690 AV-7400
MK-4601, MK-4611, MK-4621 AV-401
MP-5210, MP-5211, MP-5213 AV-7600
a
MP-5410, MP-5411, MP-5413
AV-7600 & AV-601
MP-5511, MP-5513
MPR-5610, MPR-5611, MPR-5613
MPR-5713
a
High ambient temperatures with high media temperatures in the valve may require the use of AV-601 in addition
to AV-7600. See General Instructions for AV-7600 (F-26235) and AV-601 (F-19069) for details.
Flow
Stroke
Closed
Open
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
0%
10% 20% 30% 40% 50% 60% 70% 80% 90%
100%