Vaporizer high pressure leak testing, Pressure leak testing, Testing information – Grain Systems PNEG-1798 User Manual
Page 25
7. Procedure
PNEG-1798 Tower and T-Series Dryers Vaporizer
25
7.4. Vaporizer High Pressure Leak Testing
Record all steps of this section on the data sheet.
Testing Information
The vaporizer coil and its associated piping play a vital role in the operation and efficiency of the dryer and
a safety concern for those that operate the dryer. Any leaks pose a potential for disaster and inefficient
operation. This leak test is a way of identifying leaks, large or small, prior to the initial start-up and
operation of the dryer. This test can also be performed at any time during the life of the dryer to verify no
leaks have developed. The performance of this test is also a final verification that any leaks that were
found during this test have been repaired.
The incoming liquid propane (LP) pressure to the dryer is variable and dependent on how full the
customer’s storage tank(s) is, the ambient temperature and how much sun light or shade the tank is
subjected to during the course of a day during dryer usage. Pressures may range from 40 PSIG on very
cold days and 120 PSIG on very warm days with the tank receiving direct sun light for much of the day.
Therefore the vaporizer coil and piping could be subjected to pressures as high as 120 PSIG. It is the intent
of this test to pressurize for leaks at approximately 1.5 times the highest operating pressure of the
vaporizer system. Therefore our target test pressure will be 120 PSIG x 1.5 = 180 PSIG. To go in a
conservative direction the test pressure that will be used for this procedure will be 200 PSIG (+/- 2). The
test acceptance criterion is to hold the desired pressure for 3 minutes.
Most common used portable air compressors can only achieve and sustain 80-90 PSIG; this does not
meet the desired target test pressure of 200 PSIG. The nitrogen bottle, gas regulator, high pressure hose
and 300 PSIG test gauge or instrument of
are used for the performance of
this test.
Refer to
for locations of connections.
7.4.1. Install a 2" to 1/4" reducing bushing at the end of the 2" to 1-1/4" bell reducer for the connection
of a test gauge. Some test gauges may have a 3/8" or 1/2" MNPT fitting, if so, reduce down to
allow a for the test gauge connection size.
7.4.2. Connect the nitrogen gas regulator to the nitrogen bottle. Turn the regulator handle in a
counterclockwise (CCW) until no resistance is felt on the handle. This is to make sure the
regulator has no output pressure when we open the nitrogen bottle’s valve later in this section.
The regulator’s handle will be turned clockwise (CW) later in this section to give the desired
pressure output.
7.4.3. Connect one end of a high pressure hose assembly (rated for >300 PSIG) to the output side of
the gas regulator installed on the bottle of
.
7.4.4. Connect the remaining end of the high pressure hose assembly (rated for >300 PSIG) to the inlet
side of the 3/4" gas train liquid supply high pressure isolation valve. The 3/4" valve is shown in
.
7.4.5. Tighten both ends of the hose connected in
. This is where the test pressure
of 200 PSIG will be input.