Instruction manual

ManualsBrandsEmerson ManualsOther168H

168, 168H, and 68 Series

D100275X012

Instruction Manual

Form 2256

December 2008

www.emersonprocess.com/regulators

168, 168H, and 68 Series Three-Way

Switching Valves

Introduction

The 168 and 168H Series pneumatically operated

three-way snap-acting switching valves (Figure 1) are

used to switch pressures on and off in response to a

predetermined change in an input signal pressure.

In operation, increasing pressure applied to the top of

the diaphragm through port D (see Figure 2) moves

the stem and upper range adjusting nut toward the

trip lever. When the diaphragm pressure reaches

the predetermined upper tripping pressure, the upper

adjusting nut pivots the trip lever to move the rocker

assembly to its alternate position, closing port C

and opening port B. When decreasing pressure to

the diaphragm at port D reaches the lower tripping

pressure, the spring moves the stem and lower range

adjusting nut to return the rocker to its original position,

closing port B and opening port C.

The 68 Series (Figure 4) three-way snap-acting body

assemblies can be used alone, or to form the valve

body portions of 168 or 168H Series switching valves.

With the addition of the lever knob (key 11, Figure 4)

to a Type 68-1 body assembly, a Type 68-2 manual

switching valve body assembly is formed.

Only personnel qualied through training or experience

should install, operate, and maintain these valves. If

there are any questions concerning these instructions,

contact your local Sales Ofce before proceeding.

W1932

Figure 1. Exterior of 168 Series Switching Valve

Figure 2. Construction Details of

168 Series Switching Valve

DIAPHRAGM

SPRING

ROCKER

ASSEMBLY

BODY

BODY SPRING

TRIP LEVER

LOWER RANGE

ADJUSTMENT NUT

STEM

UPPER RANGE

ADJUSTMENT NUT

M1045

INLET PRESSURE

OUTLET PRESSURE

ATMOSPHERIC PRESSURE

LOADING PRESSURE

Summary of content (8 pages)

PAGE 1
68, 168H, and 68 Series Instruction Manual Form 2256 December 2008 168, 168H, and 68 Series Three-Way Switching Valves Introduction The 168 and 168H Series pneumatically operated three-way snap-acting switching valves (Figure 1) are used to switch pressures on and off in response to a predetermined change in an input signal pressure. In operation, increasing pressure applied to the top of the diaphragm through port D (see Figure 2) moves the stem and upper range adjusting nut toward the trip lever.
PAGE 2
168, 168H, and 68 Series Specifications Maximum Allowable Pressures Flow Coefficients Diaphragm 168 Series: 100 psi (6,90 bar) 168H Series: 150 psi (10,3 bar) Cg: 7 Representative C1: 35 Pressure Connections Body: See Table 1 1/4-inch NPT female Operative Temperature Limits(1) Approximate Weights 68 Series: 0.5 pound (0,23 kg) 168 Series: 3 pounds (1,36 kg) 168H Series: 5 pounds (2,27 kg) -10° to 150°F (-23° to 66°C) Port Diameter 3/32-inch (2,38 mm) 1. This term is defined in ISA Standard S51.
PAGE 3
168, 168H, and 68 Series 168 and 168H Series Adjustment Determine the desired upper and lower switching pressures (the high and low values of diaphragm pressure at which the valve is to switch). Refer to Table 1 to ensure that these pressures are within the diaphragm pressure range and that the diaphragm pressure change between the switching pressures is within the minimum and maximum limits shown. Adjust the unit as follows. Key numbers used in this procedure are shown in Figure 3 except where indicated.
PAGE 4
168, 168H, and 68 Series Maintenance 4. Carefully drive out trip lever pin (key 2E). ! Warning To avoid personal injury or property damage from sudden pressure release or uncontrolled process fluid, isolate the switching valve from the process, release process pressure, and vent any loading pressure before starting disassembly. Because of the care Fisher® takes in meeting all manufacturing requirements (heat treating, dimensional tolerances, etc.
PAGE 5
168, 168H, and 68 Series Parts Ordering Key Description Part Number When corresponding with the local Sales Office about this equipment, state the type number and all other pertinent data found on the nameplates (key 14, Figure 3; key 10, Figure 4). When ordering replacement parts, also specify the complete 11 character part number of each part required.
PAGE 6
168, 168H, and 68 Series Reset lever b d A trip lever c d section D-d 43A8117-B B1199-1 detail of manual reset switch for use with either 168 or 168h series b A b c A c DU8774-D DU8796-D 168 Series 168H Series Figure 3.
PAGE 7
168, 168H, and 68 Series TRIP LEVER DETAIL OF TYPE 68-2 BODY FOR MANUAL OPERATION B C CU8794-F A COMPLETE TYPE 68-1 OR 68-3 BODY Figure 4.
PAGE 8
168, 168H, and 68 Series Industrial Regulators Natural Gas Technologies TESCOM Emerson Process Management Regulator Technologies, Inc. Emerson Process Management Regulator Technologies, Inc. Emerson Process Management Tescom Corporation USA - Headquarters McKinney, Texas 75069-1872 USA Tel: 1-800-558-5853 Outside U.S. 1-972-548-3574 USA - Headquarters McKinney, Texas 75069-1872 USA Tel: 1-800-558-5853 Outside U.S.