Instruction Manual Form 5086 November 1998
128-PQC
Type 128-PQC Control Valves Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 Scope of Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Installation
................................ 3
Principle of Operation
ALTERNATE LOCATION OF PIPE PLUG FOR USE AS ANGLE VALVE
................... 4
Maintenance
.............................. 4 Replacing Packing and Trim . . . . . . . . . . . . . . . . . . . 5 Changing Main Spring Range . . . . . . . . . . . . . . . . . . 6 Reversing Action or Replacing Actuator Parts . . . . 6
LOCATION OF PIPE PLUG FOR USE AS GLOBE VALVE
W2838-2*/IL
Parts Ordering . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7
Parts Kits
................................. 7
Parts List
.................................. 8
Figure 1. Type 128-PQC Control Valve
Description
Scope of Manual This manual provides installation, maintenance, and parts information for the Type 128-PQC control valve. Instructions and parts lists for Fisher Controls pneumatic instrumentation and other equipment used with this control valve are found in separate manuals. Only personnel qualified through training or experience should install, operate, or maintain the Type 128-PQC control valve. If you have any questions concerning the instructions in this manual, please contact your Fisher Controls sales office or sales representative before proceeding.
Specifications Table 1 lists specifications for the Type 128-PQC control valve. Some of the specifications for a given control valve as it originally comes from the factory are stamped on a nameplate, shown in figure 2, located on the upper diaphragm casing flange.
D100269X012
Introduction
The Type 128-PQC control valve provides on-off dump valve service for such oil production applications as separators, scrubbers, and treaters, even under sour gas conditions. It also may be used in general on-off high-pressure control of a wide variety of liquids and gases, including those which are sticky or gritty and erosive. The Type 128-PQC valve is a 1-inch combination control valve with a pipe plug in the bottom connection for straight-through globe valve flow as shown in table 1. However, the pipe plug may be field-changed to the left-hand end connection as shown in figure 3 for angle flow.