Grain Systems PNEG-1798 User Manual
Page 27
7. Procedure
PNEG-1798 Tower and T-Series Dryers Vaporizer
27
7.4.16. Verify that the closed 3/4" manual isolation valve is not leaking, by observing that there is still
0 PSIG indicated on the test gauge installed in
. If there is pressure
indicated on the test gauge the manual 3/4" isolation valve will need replaced. Notify the
cognizant GSI project manager for the correct valve replacement. Record the pressure reading
on the data sheet.
7.4.17. Slowly open the 3/4" manual isolation valve and observe there is a pressure reading on the
0-300 PSIG test gauge. The pressure should increase on the test gauge to approximately
200 PSIG, as was set on the regulator gauge of
, provided there are no
large or open ended leaks somewhere in the vaporizer system. The nitrogen cylinder regulator
may need to be adjusted to get to the desired test pressure of 200 PSIG. Record the test gauge
pressure reading on the data sheet.
7.4.18. Using leak detection solution and with the system still pressurized, go to all fittings from the
vaporizer coil connections and inside and outside connections on the vaporizer system and the
liquid line gas train piping from the 3/4" manual isolation valve where the test pressure begins.
Spray or swab the solution liberally and identify any bubbles as leaks that need repaired and the
absence of bubbles as a tight non-leaking connection. Record on the data sheet how many leaks
were initially identified in the performance of this step.
7.4.19. Repair any leaks that were identified. Pressurize the system again as described in the previous
steps and repeat
until no bubbles are present, complete this prior to going to
.
7.4.20. To verify that all leaks have been repaired and that the vaporizer system is a total leak free closed
loop system, pressurize the system to 200 PSIG (+/- 2) as indicated on the test gauge. Adjust the
regulator to reach this pressure. Record this test pressure value on the data sheet as the
beginning (0 minute) test pressure. Note the time for the beginning of this 3 minutes leak test.
7.4.21. Close the manual 3/4" liquid line valve.
7.4.22. Close the nitrogen bottle supply valve.
7.4.23. Vent the regulator by turning the regulator handle or knob CCW until no pressure is observed on
the regulator’s gauges. The regulator handle or knob may need to be turned CW with the nitrogen
cylinder’s valve still closed to completely vent any remaining pressure.
7.4.24. Verify the pressure that was recorded in
has remained stable and has not decreased
or slowly decayed. If the pressure has dropped or decreased in value, as indicated on the test
gauge, a leak is still present in the system and must be repaired prior to going to
.
7.4.25. The desired test pressure of 200 PSIG (+/- 2) must be held for 3 minutes without decreasing from
the beginning pressure of
to the 3 minutes time for a successful leak test. Record the
test pressure from the test gauge after 3 minutes.
7.4.26. Repeat any of the steps from
through
to achieve the
acceptable leak rate test criteria. Record the ‘as left’ leak rate test times and test gauge pressures
on the data sheet. This completed step should be signed and dated on the data sheet by the
person(s) performing the test and a supervisor.
CAUTION
Prior to attempting any repair of identified leaks, remove the pressure in the
system by closing the valve on the nitrogen cylinder and venting the pressure on
the regulator by turning the handle in a CCW direction. Observe any pressure that
may remain in the system by looking at the regulator gauges, the test gauge and
the 2-1/2" liquid filled 0-200 PSIG liquid line gauge. These gauges must indicate
0 PSIG or pressure is still present in the system. Do not loosen any fittings or
disconnect any lines with pressure on the system.