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Type N550
Specifications
TYPE
N550-10
N550-16
N550-24
Maximum Inlet Pressure: 400 psig (27,6 bar)
1. The pressure limits in this Instruction Manual and any applicable standard or code limitation should not be exceeded.
*Nominal Pipe Size
Operation
The Type N550 handle and shaft may
break if the valve is forced open against
the gas flow and before pressure is
equalized on each side of the main
valve disk.
To Open a Closed Valve:
Close a shutoff valve downstream of the Type N550.
Pull the Type N550 handle counterclockwise. There
will be an opening as inlet pressure helps hold the
valve disk closed against the seat. The initial opening
force on the handle opens a pilot valve in the main
valve disk, permitting pressure to build-up downstream.
When differential pressure across the main disk has
been reduced, the Type N550 can be opened without
further difficulty by continuing to lift the handle to the
open position. When the handle is fully open (handle
perpendicular to the pipe) the latch engages to hold
the valve open.
Because the valve is spring closed
(aided by pressure), the handle can snap
down with considerable force when
closing. Keep hands and fingers away
from the handle as it closes.
To Close an Open Valve:
Pushing the handle down (handle parallel to the pipe)
will close the valve.
From a remote location, pulling on the remote cable or
exhausting pneumatic pressure from the Type P327D
will retract the plunger allowing the Type N550 to close.
If emergency conditions cause the fusible element to
reach a temperature of 212°F (100°C), the element,
which attaches the handle to the shaft, pulls apart and
allows the valve to close.
2
(1)
CAUTION
CAUTION
BODY SIZES, NPS*
1-1/4 FNPT
2 FNPT
3 FNPT
Temperature Capabilities: -40° to 212°F (-40° to 100°C)
Installation
Shutoff Direction
The valves shall be installed in the fixed piping
between a storage tank and the transfer hose
connection at the truck or tank car loading/unloading
area. They can be placed in a line used either for
filling or withdrawing from the storage tank (or both).
The valve shall be installed to shutoff flow from the
tank towards the hose, enabling the valve to control
product loss in case of a hose break.
The Type N550 valves are spring closed
(aided by pressure) and shutoff flow in
one direction only. THE NAMEPLATE
FLOW ARROW SHOWS FLOW
DIRECTION FOR VALVE SHUTOFF
(see Figure 6). The arrow shall point
to the hose connection. Improper flow
direction will not shutoff flow through
the line.
When installed in horizontal piping, install with the
nameplate up. The valve can be installed in vertical
piping with the flow arrow pointing to the desired flow
direction for valve shutoff. In some cases the normal
flow through the valve may be opposite the shutoff
direction (like a back check valve).
Bulkhead Protection
The valve should be installed near the hose
connection, but shall be positioned so that any undue
strain resulting from a hose pull cannot shear the valve
or its inlet piping from the storage area piping. The
piping shall always be firmly supported and anchored
to be sure of meeting the requirement.
One preferred method of installation is shown in
Figure 2 where the pipe connection to the valve and
to the hose coupling is securely anchored in a
solid bulkhead.
PROPANE FLOW AT 2 PSI (0,14 bar)
DIFFERENTIAL, GPM (l/min)
75 (284)
115 (435)
275 (1041)
WARNING
!
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