Types N551 and N851
D450343T012
Instruction Manual
September 2015
www.fisherregulators.com
Types N551 and N851 Snappy Joe
™
Emergency
Shutoff Valves
Failure to follow these instructions or to
properly install and maintain this equipment
could result in an explosion and/or re
causing property damage and personal injury
or death.
Fisher
®
equipment must be installed,
operated and maintained in accordance
with federal, state and local codes
and Emerson Process Management
Regulator Technologies, Inc. (Emerson™)
instructions. The installation in most
states must also comply with NFPA No. 58
or ANSI K61.1 standards.
Only personnel trained in the proper
procedures, codes, standards and
regulations of the LPG or anhydrous
ammonia (NH
3
) industries should install and
service this equipment.
Introduction
Scope of the Manual
This manual provides installation and maintenance
instruction for the Types N551 and N851 Emergency Shutoff
Valves and Accessories.
Description
Type N551 Snappy Joe (Figure 1) emergency shutoff valve is
UL
®
Listed for service in Propane or Anhydrous Ammonia (NH
3
).
Type N851 emergency shutoff valve is intended for all other
compressed gas service. Reference to Type N551 also refers to
Type N851 unless otherwise specied.
The valves may be installed on both ends of transfer hoses
where the hose connects the bulk plant piping to the bobtail,
transport or tank car. They provide a quick way of shutting
off gas ow in the event of a hose rupture and meet the
requirements for such service when correctly installed with
a remote release and proper piping support. The Type N551
valve is lever operated, latch-open and quick closing valve. A
fusible element in the latch melts if the temperature reaches
212°F / 100°C, allowing the valve to close.
The following accessories are also covered:
Type P164B – Cable Release Assembly
Type P327D – Remote Pneumatic Release Assembly
Figure 1. Type N551 in Closed Position
!
WARNING
UL
®
is a mark owned by Underwriters Laboratories.
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