A67 a68 – Great Plains NH3 Safety User Manual
Page 21
Great Plains Manufacturing, Inc.
Ammonia Nurse Tanks
17
2013-07-15
407-551M
Refer to Figure 13 (some components shown exploded for
clarity - never remove any except the outlet cap).
A67 Liquid Filler Valve:
Do not open this valve. Field operators need only
confirm: valve closed, in sound mechanical
condition, and Acme cap secure.
This valve, color coded red or orange, is used only
during tank fill at a terminal.
A68 Pressure Gauge:
This gauge reports the pressure (usually in psi) of
the NH
3
gas at the top of the tank. The reading
varies with tank and ammonia temperature.
A freshly filled tank reads between 50 and 250 psi
(at air temperatures above freezing). Learn the
relationship between temperature and vapor
pressure. Do not accept a tank with a
malfunctioning gauge.
Refer to Figure 14 (some components shown exploded for
clarity - never remove any except the outlet cap).
A69 Fixed Liquid Level Gauge:
Do not open this valve. Field operators need only
confirm that the valve at this fitting is closed and is
in sound mechanical condition.
This gauge is a short dip tube, with its lower end at
the 85% fill level in the tank. During filling, if terminal
personnel have any doubt about the reading on the
float gauge
, they may open the fixed gauge and
see if what is released is gas or liquid. This is a
hazardous operation requiring terminal PPE
a
.
A70 Vapor Valve:
Do not open this valve. Field operators need only
confirm that this valve is closed, is in sound
mechanical condition, and that the Acme cap is
secure.
This valve, color coded yellow, is used during fill
operations to recapture NH
3
gas from the top of the
tank, as liquid fills the bottom. It is closed for all
other operations.
A vapor return valve may have a [time-dated]
excess flow valve.
a. PPE: Personal Protective Equipment
Ammonia Release Hazard:
At 120
°F (40°C), the vapor pressure reaches 250 psi. Above
this point, the relief valve (
on page 21) periodically
operates, and small NH
3
releases occur.
Figure 13
Filler Valve and Pressure Gauge
31574
A67
A68
NH
3
GAS
NH
3
LIQUID
Figure 14
Fixed Gauge and Vapor Valve
31574
A69
A70
A71
NH
3
GAS
NH
3
LIQUID
A71