HANKISON SPXFLOW HSHD Series, Инструкция по эксплуатации

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3.0 Description
3.1 Function
Dual tower regenerative desiccant dryers are utilized to dry
compressed air to dew points below the freezing point of
water or reduce the moisture content to low levels for use in
critical process applications.
Air is dried by using two identical towers, each containing a
desiccant bed. While one tower is on-stream drying the com-
pressed air, the other tower is off-stream being regenerated
(reactivated, i.e., dried out).
Desiccant dryers lower the dew point by adsorbing most of
the water vapor present onto the surface of the desiccant.
Adsorption occurs until an equilibrium is reached between
the partial pressure of the water vapor in the air and that on
the surface of the desiccant.
Desiccant can then be regenerated by desorbing the water
collected on its surface. Regeneration occurs by expanding a
portion of the dried air to atmospheric pressure. This very dry
air (called purge air) causes the moisture to desorb from the
desiccant and then carries the desorbed water out of the dryer.
3.2 Operation
The Drying Circuit: Up-Flow Drying
A. The incoming compressed air travels through the oil removal
pre-filter (1) and enters the top manifold assembly (2).
B. A shuttle valve and flow distributor direct the airflow down-
ward through a transfer tube (3) to the bottom manifold
assembly (4).
C. The dried compressed air moves through a flow distributor
to the dryer outlet (6).
D. The air travels through particle removal after-filter (7). The
clean, dry air is now ready use.
1) In the Class 2 fixed mode (-40°F pdp), the on-line car-
tridge dries the air for a period of 4 minutes.
2) In the Class 1 pdp mode (-94°F pdp), the on-line cartridge
dries the air for a period of 2 minutes.
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2
3
6
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4
Inlet Air
Outlet Air
Example above: Le � tower drying / Right tower regenera � ng
Up-Flow Drying
The Regeneration Circuit: Down-Flow Regeneration
A. A portion of the ultra-dry air is throttled to near atmo-
spheric pressure through a purge orifice (1) directing the air
through the right desiccant cartridge (2). The water vapor
is effectively desorbed from the desiccant.
B. The purge air then passes through flow distributor (3),
upward through purge valve (4) and purge air muffler (5),
then exhausted to atmosphere.
1) In the Class 2 (-40°F pdp) fixed dew point mode, the
dryer regenerates for 3 minutes and 20 seconds. The
purge valve then closes, slowing repressuring in the
right cartridge for 40 seconds to line pressure. With the
right cartridge fully regenerated, it is now prepared to
go online & dry the air.
C. After 40 seconds of repressurization, the left purge valve
opens (6) & depressurizes. The offline tower is now ready
to go back on-line.
D. This moves the inlet shuttle valve moves into position. The
incoming air now passes through the shuttle valve (via the
flow distributor) to the right desiccant cartridge, where it
is dried to the desired dew point.
1) In the Class 2 fixed mode, the full cycle time is 8 minutes
– 4 minutes drying & 4 minutes regenerating.
2) In the Class 1 fixed mode, the full cycle time is 4 minutes
– 2 minutes drying & 2 minutes regenerating.
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3
1
4
Inlet Air
Outlet Air
Example above: Le� tower drying / Right tower regenera�ng
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Down-Flow Regeneration