377 Series Trip ValvesProduct Bulletin

62.3:377September 2004

6

SPRING

VALVE PLUG

UPPERDIAPHRAGM

EXHAUSTPORT

SUPPLYPRESSURE

LOWERDIAPHRAGM

PORT D

PORT E

LOWERPORTS

PORT F

PORT C

PLUG ASSEMBLIES

UPPER PORTS

PORT B

PORT A

VENT

MAIN SPRING

ACTUATOR

CONTROLDEVICE

CHECKVALVE

VOLUMETANK

Figure 7. Type 377U Trip Valve Shown Tripped

A2281-1 / IL

Figure 8. Volume Tank Sizing Graph

Volume Tank Sizing

Note: State and local regulations may require theuse of ASME-approved volume tanks. It is theusers responsibility to determine requirementsand applicable regulations for proper volumetank selection.

Seven different tanks of varying capacities areavailable. The volume tank must be selected so thatits pressure at any time is greater than the minimumpercentage of maximum supply pressure required tostroke the actuator (see figure 8).

377 Series Trip Valves

Product Bulletin62.3:377September 2004

7

1. Size the volume tank as indicated below:

For Actuators onSliding Stem Valves,

Determine:

For Actuators onRotary-Shaft Valves,

Determine:

Y = F/AP x 100 Y = Pr/P x 100

Where:

Y = Minimum failure positioning percentageF = Actuator thrust required in normal operation toposition the valve at the desired limit of travelA = Effective piston area (from the appropriateactuator bulletin)P = Maximum supply pressure availablePr = Highest pressure required by the actuator tostroke the valve (from the appropriate actuator sizingtechnique)

2. With the minimum failure positioning percentageobtained in step 1, enter the value on the abscissa ofthe graph in figure 8. Locate the corresponding pointon the curve, and read across to find the volume ratio,R.

3. Determine:

VT = (XA)/R

Where:X = Maximum actuator travel from the appropriateactuator bulletin. For rotary actuators, substitute totaldisplacement (XA). Actuator displacement can befound in the product bulletin, or contact your Fishersales office.VT = Minimum volume tank size requiredR = Volume ratio from step 2

Installation

The 377 Series trip valve may be mounted in anyposition without affecting normal operation.Dimensions are shown in figure 9 and tables 2 and 3.

Table 1. Guidelines for Specifying 377 Series Trip Valve

Actuator Type Fail ModeValve

Action(1) Trip Valve

Fail OpenPDTC 377U

Sliding-Fail Open

PDTO 377DSlidingStem

Fail ClosedPDTC 377D

Fail ClosedPDTO 377U

Rotary--

FullyClockwise

Clockwise to

377CWRotary

Type 1035,Series G

FullyCounter-clock

wise

Clockwise toClose

377CCW

Rotary--

FullyClockwise

- - - 377CWRotary

Type 1069 Fully Counter-clockwise

- - - 377CCW

1. PDTC—Push Down to Close; PDTO—Push Down to Open

Ordering Information

Note: Fisher does not assume responsibility forthe selection, use, or maintenance of anyproduct. Responsibility for proper selection, use,and maintenance of any Fisher product remainssolely with the purchaser and end user.

When ordering specify:

Application1. Available supply pressure2. Actuator type number and size3. Input signal range4. Operating ambient temperature5. Trip point (If the trip point is not specified, the unitis factory-set to trip at 72 percent of supply pressureor 2.8 bar (40 psig), whichever is higher.)6. Volume tank size

Trip Valve

Refer to the specifications. Review the informationunder each specification and in the referencedfigures. Specify the desired choice wherever there isa selection to be made. Be sure to specify the typenumber as described in the Available Configurationsspecification.

Refer to table 1 for guidelines on specifying thecorrect trip valve.

377 Series Trip ValvesProduct Bulletin

62.3:377September 2004

8

Table 2. Standard Volume Tank Dimensions

Tank Volume J L

Liters Inch3 mm Inches mm Inches

11.821.633.4

42.965.6

72113152036

26154001

309310309

309309

12.1612.1912.16

12.1612.16

318451607

7371095

12.517.7523.88

29.0043.12

131.1 8002Requires two 65.6 liter (4001 inch3) volume

tanks

Table 3. ASME-Approved Volume Tank Dimensions

Tank Volume J L

Liters Inch3 mm Inches mm Inches

8.524.930.0

42.868.871.6

51815201831

260941994371

208305254

305360305

8.1912.0010.00

12.0014.1912.00

337427684

681792

1087

13.2516.8126.94

26.8131.1942.81

143.2 8742Requires two 71.6 liter (4371 inch3) volume

tanks

Canadian Registered

114227303

454

69301386018480

27720

406508610

610

162024

24

103412861295

1932

40.6950.6351.00

76.06

908 55440Requires two 454 liter (27720 inch3) volume

tanks

AF4605-K

19A7995-A

A2778-4 / IL

57(2.25)CAPREMOVALCLEARANCE

0.25 18 NPTVENT CONNECTION

mm(INCH)

76(3.00)

90(3.56)

54(2.12)

141(5.56)

46(1.81)

100(3.94)

154(6.06)

PORT D

PORT E

PORT F

PORT C

STANDARD

TANK

ASME−APPROVED

TANK

LL

JJ

0.25 18 NPTSUPPLY CONNECTION

1 1

NOTEREFER TO TABLES 1 AND 2 FOR J AND L DIMENSIONS1

Figure 9. Dimensions of Trip Valve with Manifold (also see tables 2 and 3)

Fisher Marshalltown, Iowa 50158 USACernay 68700 France Sao Paulo 05424 BrazilSingapore 128461

The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure their accuracy, they arenot 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 and end-user.

�Fisher Controls International LLC 1985, 2004; All Rights Reserved Printed in USA

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