Bulletin 71.7:167A November 1981
Type 167A Three-Way Switching Valve Introduction The Type 167A three-way switching valve (figure 1) is usually installed to provide switching or lock-up action in the event that system operation deviates from normal. The compact size and simplicity of this valve make it especially suitable for field or panel mounting.
Features • Convenient Installation—Compact construction permits easy handling and installation. • Easy, Accurate Adjustment—The switching point is set to a specific requirement by an adjusting screw atop the spring case.
W1947
Figure 1. Type 167A Three-Way Switching Valve
• Easy Maintenance—With the bottom piping disconnected, the valve can be completely disassembled without removing it from the line. CONTROL SPRING
Principle of Operation For the following operational sequence, refer to figures 2 and 3. The normal flow path, with no pressure applied to the diaphragm, is from connection A to connection C. As pressure is applied (connection D, figure 3), it registers under the diaphragm and opposes the spring. When the pressure under the diaphragm nears the spring setting, the pressure overcomes the spring, and moves the diaphragm assembly up. This allows the valve plug spring to lift the valve plug and provides flow through connection B. The flow path is then from connection A to connection B. When the pressure under the diaphragm decreases, the control spring moves the valve plug down and covers the opening to connection B.
VALVE PLUG
VALVE PLUG SPRING W0109-1
Figure 2. Sectional of Type 167A Three-Way Switching Valve
Table 1. Spring Selection SPRING RANGE, PSIG (bar) Panel Mounted
5 to 18 (0,3 to 1,2) 18 to 30 (1,2 to 2,0) 30 to 100 (2,0 to 6,9)
5 to 12 (0,3 to 0,8) 12 to 20 (0,8 to 1,4) 20 to 80 (1,4 to 5,5)
1B 986027212 1B 788327022 1K 748527202
SPRING COLOR CODE Green Silver Red
MAXIMUM PRESSURE CHANGE ON DIAPHRAGM FOR FULL STROKE, PSID (bar d) 5 (0,3) 8 (0,6) 15 (1,0) DD200077X012
Standard
SPRING PART NUMBER
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Bulletin 71.7:167A Specifications Body Size and End Connection Style 1/4-inch (DN 8) NPT (connections A, B, and C) Maximum Inlet Pressure(1) 250 psig (17,2 bar) at connections A, B, and C Control Connection 1/4-inch NPT female (connection D) Pressure Switching Adjustment May be adjusted throughout each spring range by rotating the adjusting screw Maximum Control Pressure to Diaphragm 100 psig (6,9 bar) at connection D Spring Ranges See table 1 Material Temperature Capabilities(1) Nitrile (NBR): –20° to 150°F (–29° to 66°C) Fluoroelastomer (FKM): 0° to 350°F (–18° to 177°C)
Construction Materials Body: Aluminum Spring Case: Aluminum Spring: Steel Disk: Nitrile or Fluoroelastomer Disk Holder: Aluminum Diaphragm: Nitrile or Fluoroelastomer Valve Stem: Aluminum Flow Coefficients Cg(2) Connection A to B: 11.5 Connection A to C: 13.3 C1: 35 Approximate Weight 1 pound (0,5 kg) Option Tapped spring case for pressure loading
1. The pressure/temperature limits in this instruction manual or any applicable standard limitation should not be exceeded. 2. Cg given for 25 psig (1,7 bar) inlet pressure and full drop across body.
Installation
1.25 (32)
0.31 (8) DIAMETER 2 MOUNTING HOLES 6.31 (160) MAXIMUM 1.69 (43)
The Type 167A switching valve may be installed in any position. Dimensions are shown in figure 3.
Ordering Information When ordering, specify the following: 1. Type number
1.88 (48) 1.25 (32)
2.88 (73)
B
0.5 (13) 1.25 (32)
PANEL MOUNTING INCHES (mm)
2. Spring range 3. Spring setting 4. Type of spring case (standard or panel mounting)
STANDARD (FIELD) MOUNTING
Figure 3. Dimensions Fisher is a mark owned by Fisher Controls International, Inc., a business of Emerson Process Management. The Emerson logo is a trademark and service mark of Emerson Electric Co. All other marks are the property of their respective owners. The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure their accuracy, they are not to be construed as warranties or guarantees, express or implied, regarding the products or services described herein or their use or applicability. We reserve the right to modify or improve the designs or specifications of such products at any time without notice. Fisher does not assume responsibility for the selection, use or maintenance of any product. Responsibility for proper selection, use and maintenance of any Fisher product remains solely with the purchaser.
For information, contact Fisher: Marshalltown, Iowa 50158 USA McKinney, Texas 75070 USA 28320 Gallardon, France 40013 Castel Maggiore (BO), Italy Sao Paulo 05424 Brazil Singapore 128461 ©Fisher Controls International, Inc., 1981; All Rights Reserved
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