Selection Guide

Table Of Contents

System Design Considerations

Linked Globe Valve Assemblies

Note: The information in this section describes characteristics of the VB-7xxx and VB-9xxx valve bodies, which are used in the

Vx-7xxx and Vx-9xxx valve assemblies. This information is also useful when installing the Mx4x-xxxx-2xx series

actuator/linkage assemblies onto these valve bodies.

Control Precision

2-Way Valves: 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-72xx and VB-92xx series valves.

Stroke

Closed

Open

100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Rated Flow

Figure-1 Typical Modified Equal Percentage Flow Characteristics.