Taylor-Wharton EF-450 - Manual (Page 13)

Safety Devices
The Express Fill 450 features a safety valve to prevent over pressurization of the vessel. The safety valve
(SV-1) relieves pressure when it exceeds the maximum operating pressure of the vessel. The valve reseats
when pressure drops below this point. In addition, the primary safety valve is supported by a secondary relief
device consisting of a rupture disc (R-1). The rupture disc requires replacement in the event a safety valve
malfunctions and allows vessel pressure to reach the burst pressure rating.
A relief valve (SV-2), set to open at 22 psig, is provided on the DOT models. Closing the isolation valve (V-
5) prevents flow through the relief valve. This feature is useful if it is necessary to transport the Express Fill
450 at a reduced pressure. It also allows liquid to be stored at a low pressure. This is reduces product loses
when using the Express Fill 450 to dispense cryogenic liquid.
SV-1
SV-2
R-1
PI-1
V-5
Figure 7: Safety circuit highlighted in blue.
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