Van Air Systems FD-250 - Manual (Page 2)

PAGE 2
A Blast Pak is a skid mounted system consisting of an air-cooled trim cooler, a single tower dryer with a bed of desiccant tablets and a coarse
afterfilter. Wet warm air enters the trim cooler where it is cooled to a temperature approaching ambient. Water is condensed out during this
cooling process. The saturated air and the liquid water proceed to the inlet of the single tower dryer. The liquid water and any solid particles
present are separated by gravity and fall to the dryer sump area. The process air moves upward through the bed of desiccant tablets which
attract and absorb moisture from the air before it flows through the dryer outlet. The tablets dissolve gradually as they absorb the moisture.
The solution, which consists of dissolved desiccant and water, falls into the sump area at the bottom of the vessel. The dryer must be drained
periodically to remove the accumulated solution. A manual ball valve is supplied for this purpose. A pneumatic drain valve is available as
optional equipment for automatic draining. Likewise, the desiccant in the dryer must be periodically replenished to maintain performance. The
coarse afterfilter is supplied to catch any residuals that may work their way downstream.
SECTION 1 DESCRIPTION OF OPERATION
2.1 INLET CONDITIONS
The FD-250 and the FD-250-DC Blast Paks are rated for 250 SCFM at 100 PSIG, 180° F into the trim cooler [sized for 90° F ambient and 10°
approach (FD-250-DC) and 15° approach (FD-250)]. Approach temperatures will vary with changes to the inlet conditions (flow, pressure,
temperature) and the ambient temperature. The dew point out of the dryer tower is directly related to the inlet temperature entering the dryer
vessel. The lower the inlet temperature, the lower the dew point of the outlet air.
The aftercooler maximum inlet temperature is 250° F. When using DRY-O-LITE desiccant, the inlet temperature to the dryer tower should not
exceed 100° F.
SECTION 2 PERFORMANCE
2.2 MAXIMUM CAPACITIES FOR DRYER - SCFM (Nm 3 /hr)
MAXIMUM
WORKING
PRESSURE
200 PSIG
13.8 Bar
100 PSIG
6.9 Bar
250
402
125 PSIG
8.6 Bar
304
489
150 PSIG
10.3 Bar
359
577
60 PSIG
4.1 Bar
163
262
80 PSIG
5.5 Bar
206
331
SECTION 4 OPERATION
175 PSIG
12.1 Bar
413
664
200 PSIG
13.8 Bar
468
752
3.1 PRESSURE RELIEF VALVE
A 1" NPT coupling is provided on the back of the dryer vessel for
installing the relief valve. A pressure relief valve should be installed to
conform to OSHA safety standards. Refer to OSHA Standard Section
1910.169, paragraph “b”, subparagraph “3” and all other federal, state
or local codes concerning pressure vessels.
See section 6 for recommended relief valve (available from your Van
Air rep.)
3.2 PNEUMATIC DRAIN VALVE (P/N 39-0284)
The 1"NPT drain connection can be fitted with a PDV-500T pneumatic
drain valve for automatic draining of the vessel. Ask your local Van
Air representative for details.
SECTION 3 OPTIONS
4.1 DESICCANT INSTALLATION
IMPORTANT
The Blast Pak is shipped WITHOUT the desiccant installed.
The desiccant MUST BE INSTALLED before using the
system.
THE USE OF CHEMICALS OTHER THAN VAN AIR
DESICCANT WILL VOID THE WARRANTY ON THE DRYER.
4.2 LUBRICATOR OIL (FD-250 only)
Check oil level in lubricator regularly and add oil as required.
Note: 1 Quart of oil shipped with the BlastPak.
IMPORTANT
The Blast Pak is shipped WITH the lubricator oil installed.
4.4 START UP PROCEDURES
SLOWLY pressurize the air system. Allow some air to bleed
through the manual drain valve. Once the system starts to
pressurize, the manual drain valve can be closed. The Blast
Pak is now in operation.
CAUTION
Make sure that the Blast Pak is not subjected to sudden
flow surges. Always open the valves slowly to permit
gradual equalization of pressure between the Blast Pak and
the air supply lines.
The procedure for filling the dryer with desiccant is outlined in
Section 5.6 of this manual.
3.3 GAUGE KITS
A 1/2" NPT connection is provided on the lower front of the dryer
for installing gauges.
See Section 6 for optional gauge kits (available from your Van Air rep.)
Verify that regulator pressure is set as shown on page 1 of
this manual to maintain 3450 rpm fan speed to ensure proper
aftercooler performance. (FD-250 only)
4.3 ELECTRICAL CONNECTIONS (FD-250-DC only)
Electrical requirement for trim cooler motor is 12 VDC 19 Amps.
Connect 12 VDC supply to the air motor by using optional male
plug shown in section 6 of this manual. Another way to make
the connections is to cut the plug off the motor leads and
wirenut the supply wires to the motor wires.
The BLUE wire is POSITIVE and the BLACK wire is NEGA-
TIVE.
Make sure all electrical connections comply with the National
Electrical Code and all applicable state and local codes.