Van Air Systems D42-D84 - Manual (Page 7)

PAGE 7
4.5 ADDITION OF DESICCANT
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 nut until it is snug only. 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 A
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.
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 wing nut on the hatch cover. Do not remove the nut, or
the cover will fall into the vessel.
Push on the hatch cover. If the vessel is depressurized, the cover will
unseal. Once the seal is broken, slide the handle so that it is parallel
with the centerline of the long side of the opening. Tilt the hatch cover
and remove it from the dryer.
Add the amount of desiccant tablets required to raise the supply to
the normal 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 covet. If is damaged, it must be
replaced. The gasket should be replaced every time.
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 wing nut
on the hatch cover. Overtightening will cause damage to the nut. The
cover will seal when the vessel is pressurized.
Start the dryer following the start up procedures in Section 3.1
4.5-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 upon 1 shift for a one year period @ 100 psig inlet pressure
and 75 o F inlet temperature, 100% RH.)
FLOW
SCFM
100
1,000
10,000
DRY-O-LITE
LBS/YEAR
132
1,320
13,200
SP
LBS/YEAR
665
6,650
66,500
10 BF
LBS/YEAR
576
5,760
57,600
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 change 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.
4.5-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