Van Air Systems D12-D36 - Manual (Page 7)

PAGE 7
WARNING
DO NOT REMOVE, REPAIR, OR REPLACE ANY ITEM ON
THE DRYER WHILE IT IS UNDER PRESSURE.
DEPRESSURIZE THE DRYER COMPLETELY BEFORE
STARTING INSTALLATION AND/OR MAINTENANCE
PROCEDURES. SERIOUS PERSONAL INJURY MAY
RESULT IF THESE SAFETY RULES ARE NOT FOLLOWED.
DO NOT REMOVE THE HATCH COVER UNTIL ALL AIR
PRESSURE IS OUT OF THE VESSEL. PUSH ON THE
HATCH COVER BY HAND TO FIND OUT IF THE VESSEL
PRESSURE IS REDUCED TO ZERO.
DO NOT TRY TO TIGHTEN THE HATCH COVER IF YOU
HEAR OR FEEL A LEAK. IMMEDIATELY SHUT OFF THE
AIR OR GAS SUPPLY TO THE VESSEL AND REDUCE
THE DRYER PRESSURE TO ZERO.
ALWAYS INSTALL A NEW GASKET EVERY TIME THE
HATCH COVER IS REMOVED, OR AT LEAST ONCE PER
YEAR. REPLACE THE HATCH COVER EVERY FIVE
YEARS REGARDLESS OF CONDITION. USE VAN AIR
AUTHORIZED PARTS ONLY.
DO NOT USE POWER TOOLS OR CHEATER BARS TO
TIGHTEN THE NUT ON THE COVER. TOO MUCH FORCE
CAN DISTORT THE COVER AND/OR THE GASKET. IF
DAMAGED BY OVERTIGHTENING, THE COVER CAN
BLOW OUT AND CAUSE SERIOUS INJURY. (Note:
Tighten the nutonly until it is snug . When pressure is in
the vessel, the seal will be complete.)
INSPECT THE COVER AND SEALING SURFACE EVERY
TIME THE COVER IS REMOVED, OR AT LEAST ONCE
PER YEAR, FOR DAMAGE SUCH AS CORROSION,
CRACKS, OR DISTORTION. IF THERE IS ANY DAMAGE,
INSTALL A NEW COVER AND GASKET. USE VAN AIR
AUTHORIZED PARTS ONLY.
4.4 ADDITION OF DESICCANT
Open the bypass valve. Close the dryer inlet and outlet isolation
valves. If the bypass and inlet and outlet isolation valves were not
installed, shut down the air system.
Open the drain valve and allow the dryer to depressurize completely.
Loosen the nut on the hatch cover.
Push on the hatch cover. If the vessel is depressurized, the cover will
unseal. Once the seal is broken, tilt the hatch cover and remove it
from the dryer.
Add the amount of desiccant tablets required to raise the supply to
the maximum operating level or to maximum level (see FIGURE 5);
then level off the tablet bed.
CAUTION
Make sure that the desiccant does not cover the screen
on the outlet pipe.
Do NOT overfill the vessel. Adequate space must be left
to allow the hatch cover to be installed.
Check the condition of the hatch cover. If it is damaged, it must be
replaced. The gasket should be replaced every time the hatch cover
is removed or at least once a year.
Check the sealing surface of the opening. If it is contaminated with
dirt or rust, it must be cleaned before installing the hatch cover. A
contaminated surface may prevent the gasket from properly sealing.
Install the filler hatch cover and gasket. Finger tighten the nut on the
hatch cover. Overtightening will cause damage to the nut. The cover
will seal when the vessel is pressurized.
Start up the dryer following the procedures in Section 3.1.
To use the chart, first determine the SCFM that is being
processed through the dryer. Locate the nearest flow rate listed
on the chart and interpolate as necessary.
The consumption rate is proportional to the moisture loading.
Each 20 o F increase in inlet temperature changes the moisture
loading by a factor of nearly 2:1.
The quantity shown in the consumption rate chart is NOT the
quantity that must be added to the dryer at one time. The bed
level should be maintained at least to the minimum level at all
times to ensure optimum drying capabilities. The consumption
rate is an approximation of how much desiccant will be
added over a period of one year.
4.4-B DESICCANT USAGE GUIDE
The chemical and physical characteristics of Van Air desiccant
contribute to its effectiveness and economy.
The DESICCANT CONSUMPTION RATE should be used as a
guide to estimate the usage of desiccant your installation will require.
The formula is based on an annual usage rate of one shift per day,
5 days per week and 50 weeks per year or 2,000 operating hours per
year. The figure is an average and may vary depending upon your
actual conditions (i.e. 24 hour operation, higher inlet temperature,
excessive liquid water content and/or contaminants.)
DESICCANT CONSUMPTION
(Based on 1 shift for a one year period @ 100 psig inlet pressure and
75 o F inlet temperature, 100% RH.)
FLOW
SCFM
20
50
100
200
300
500
700
1000
DRY-O-LITE
LBS/YEAR
26.4
66.0
132.0
264.0
396.0
660.0
924.0
1320.0
SP
LBS/YEAR
133
332.5
665.0
1330.0
1995.0
3325.0
4655.0
6650.0
10 BF
LBS/YEAR
115.2
288.0
576.0
1152.0
1728.0
2880.0
4032.0
5760.0
4.4-A BED LEVEL GUIDE
To determine the supply of desiccant in the dryer, insert a
measuring stick through the filler hatch until it reaches the top of
the desiccant bed; dimensions in FIGURE 5 are calculated from
the filler hatch to levels indicated on the drawing. (NOTE:
Dimensions are approximate and are intended as a general guide
only.)
SECTION 4 MAINTENANCE