Groth 8860 User Manual

Installation, Operation and Maintenance Manual for

Back Pressure Regulator

Model 8860

IOM-8860

Rev. B 12541

©2009 Groth Corporation

Ref. ID: 95565

IOM -8860

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Table of Contents

I. INTRODUCTION 3

II. DESIGN AND FUNCTION 4

III. SAFETY WARNINGS 5

IV. INSPECTION AND STORAGE 5

V. INSTALLATION 6

a. 6
b. 6

VI. MAINTENANCE 7

a. FIGURE 4 – 7
b. TABLE 3 – 8

VII. VALVE TESTING PROCEDURE 8

VIII. MODEL IDENTIFICATION 9

APPENDIX A – MODEL 1200A PRESSURE/VACUUM RELIEF VALVE 10
APPENDIX B – MODEL 1220A PRESSURE/VACUUM RELIEF VALVE 11
APPENDIX C – MODEL 1260A PRESSURE RELIEF VALVE 12
APPENDIX D – MODEL 1300A VACUUM RELIEF VALVE 13
APPENDIX E – MODEL 1360A VACUUM RELIEF VALVE 14
APPENDIX F – MODEL 2300A PRESSURE RELIEF VALVE 15

13650 N. Promenade Blvd. * Stafford, TX 77477

Office: (281) – 295-6800 * (800) – 354-7684 * Fax: (281) – 295-6999 * www.grothcorp.com

IOM -8860

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I. INTRODUCTION

The Groth Model 8860 Back Pressure Regulator controls upstrea m pressure in a process line such as
an anaerobic digester gas control system. The pressure setting is obtained by adjustable spring
compression and opening is caused by upstream pressure acting on a large diaphragm. A visible scale
indicates approximate set pressure. Springs are available for various standard and special set
pressure ranges.

The regulator must be maintained by a knowledgeable valve technician. It should only be assembled
under clean conditions, preferably in a shop environment. Carefully read and understand this manual
before attempting to adjust set pressure or flow capacity, or repair the regulator.

For information not contained in this manual, please contact:

Groth Corporation

13650 N. Promenade Blvd.

Stafford, TX, 77477 USA

Phone: [phone]

Fax: [phone]

www.grothcorp.com

13650 N. Promenade Blvd. * Stafford, TX 77477

Office: (281) – 295-6800 * (800) – 354-7684 * Fax: (281) – 295-6999 * www.grothcorp.com

IOM -8860

Page 4 of 13

II. DESIGN AND FUNCTION

The Groth Model 8860 Back Pressure regulator is a high capacity, low pressure in-line pressure relief
valve. It controls upstream pressure by discharging excess vapor downstream.

When the diaphragm force, due to upstream pressure, equals the spring compression, the regulator
begins to open. Opening is controlled to accommodate the required vapor flow. Full capacity is
achieved at 15-25% over-pressure [above set pressure]. When system pressure returns to set
pressure or below, the regulator closes.

Upstream vapor pressure, acting on a large diaphragm, forces the regul ator open at the specified set
pressure. For best performance, set pressure should be sensed at a remote location at least ten pipe
diameters upstream from the regulator. The upstream pressure acts on the lower surface of the
diaphragm. The upper side of the diaphragm must be vented to atmosphere.

Set pressure is determined by the compression of the spring; the greater the compression of the
spring, the higher line pressure required to overcome the spring force. The scale located on the
regulator is a close approximation of the set pressure. A manometer is recommended for a high
accuracy reading of the set pressure. The manometer should be plumbed upstream of the Back
Pressure Regulator, at lease ten pipe diameters.

The seat and disc are lapped flat surfaces with metal to metal contact.

III. SAFETY WARNINGS

This section is intended as an overview of safety guidelines that should be followed during the
installation, operation and maintenance of the Groth Model 8860 Back Pressure Regulator. To
understand the context of these warnings and instructions, read and understand this complete manual.

In the event of an actuator diaphragm failure, the regulator will fail in the CLOSED position.
Vapor flow will be shut off. WITHOUT PROPER PIPELINE PRESSURE SENSING, EXCESSIVE
PRESSURE CAN BE REACHED.

Regulator flow capacity is based on a fully open regulator flowing air or a vapor with SG=0.7.
Consult factory for capacity under other conditions.

DO NOT attempt to re-adjust the set pressure beyond the limits specified in Table 3.
The regulator is to be connected to the upstream line with a minimum .31" ID tubing sense line.

This line must be kept open and unobstructed to ensure that the regulator senses the actual
line pressure. Long sense lines may require a larger diameter and care must be taken DURING
INSTALLATION to assure that the line is self-draining.

DO NOT attempt to remove the regulator from the line or perform field repairs in line without
first isolating the regulator from both upstream and downstream systems.

The regulator body and actuator housing are exposed to process vapors. Observe all safety
precautions as specified on the Material Safety Data Sheet(s) for the prod uct(s) that are in the
system.

The vent on the upper actuator housing must be clean and open to the atmosphere and SHALL
be inspected periodically.

The recommended set pressure range of the regulator spring is stamped on the namep l ate.
Never adjust a spring for a set pressure beyond its design range as specified in Table 3.

13650 N. Promenade Blvd. * Stafford, TX 77477

Office: (281) – 295-6800 * (800) – 354-7684 * Fax: (281) – 295-6999 * www.grothcorp.com