6
3.0 Maintenance
A. When to Replace Filter Element
NOTE: Grades 7,6,5,3,1 - complete element is replaced;
Grade 9 - unless separator core is damaged outer sleeve
only is replaced.
1. Grade 6 (dry desiccant afterfilter)
Initial drop: 1 psi (0.07 kgf/cm
2
). Pressure drop
increases as element loads with solid particles.
Replace when pressure drop reaches 6 psi
(0.42 kgf/ cm
2
) (indicator in yellow area) or annually,
whichever occurs first. Reference page 7, Figure 3.3
for gauge scale detail.
2. Grade 11 (mechanical separator)
Element should not require replacement unless physi-
cally damaged. If sludge accumulates, element can be
removed and cleaned with soap and water.
3. Grades 9,7,5,3
a. Initial (dry) pressure drop: 1 psi (0.07 kgf/cm
2
) to
2 psi (0.14 kgf/cm
2
)
b. Operating pressure drop: As filter becomes liquid
loaded (wetted), pressure drop will increase to 2 to
6 psi (0.14 to 0.42 kgf/cm
2
). Further pressure drop
occurs as element loads with solid particles.
c. FOR MAXIMUM FILTRATION EFFICIENCY, REPLACE
ELEMENT WHEN PRESSURE DROP REACHES 6 PSI
(0.42 KGF/CM
2
) (INDICATOR IN YELLOW AREA) OR
ANNUALLY, WHICHEVER OCCURS FIRST. Reference
page 7, Figure 3.3 for gauge scale detail.
NOTE: Pressure drop may temporarily increase when flow
is resumed after flow stoppage. Pressure drop should
return to normal within one hour.
NOTE: Grades 5 and 3 - During normal operation bottom
of foam sleeve will have a band of oil. Spotting above the
band indicates that liquids are accumulating faster than
they can be drained and that prefiltration is required.
4. Grade 1 (activated carbon filters)
a. Adsorption capacity - 1000 hours at rated capacity.
Element life is exhausted when odor can be
detected downstream of the filter.
B. Procedure for Element Replacement
THIS FILTER IS A PRESSURE CONTAINING
DEVICE. DEPRESSURIZE BEFORE SERVICING. If filter has not
been depressurized before disassembly, an audible alarm
will sound when the bowl begins to be removed from the
head. If this occurs, stop disassembly, isolate and
completely depressurize filter before proceeding.
1. Isolate filter (close inlet and outlet valves if installed) or
shut off air supply.
2. Depressurize filter by slowly opening manual drain
valve.
C. Flow Capacity
Maximum air flow for the various filters at 100 psig
(7 kgf/ cm
2
) is indicated in Table 1. To determine maximum
air flows at inlet pressures other than 100 psig (7 kgf/cm
2
),
multiply flow from Table 1 by air flow correction factor
from Table 2 that corresponds to the minimum operating
pressure at the inlet of the filter.
NOTE: Filters should not be selected by pipe size. Select
using flow rate and operating pressure only.
Table 1 - Maximum Flow @100 psig [7 kgf/cm
2
]
Housing
scfm
[m
3
/hr]
12
20
[35]
16
35
[60]
20
60
[105]
24
100
[170]
28
170
[290]
32
250
[425]
36
375
[640]
40
485
[825]
44
625
[1060]
48
780
[1325]
Table 2 - Air Flow Correction Factor
Maximum
Inlet
Pressure
psig
20
30
40
60
80 100 120 150 200 250 300
kgf/cm
2
1.4 2.1 2.8 4.2 5.6 7.0 8.4 10.6 14.1 17.6 21.1
Correction Factor
0.30 0.39 0.48 0.65 0.82 1.00 1.17 1.43 1.87 2.31 2.74