DANGER—Immediate hazard which will result in severe
injury or death.
This equipment is designed and built with safety as a
prime consideration; industry-accepted safety factors
have been used in the design. Each dryer is checked at
the factory for safety and operation. All pressure vessels which fall under the scope of ASME Section VIII,
are hydrostatically tested in accordance with the latest
addenda. A factory-installed safety relief valve is standard
on each dryer.
WARNING — The following safety rules must be
observed to ensure safe dryer operation. Failure to
follow these rules may void the warranty or result in
dryer damage or personal injury.
1. Never install or try to repair any dryer that has been
damaged in shipment. See the Receiving and Inspection instructions in this manual for appropriate
action.
2. This equipment is a pressure-containing device.
Never operate the dryer at pressures or temperatures
above the maximum conditions shown on the data
plate.
Never dismantle or work on any component of the
dryer or compressed air system under pressure.
Vent internal air pressure to the atmosphere before
servicing.
3. This equipment requires electricity to operate. Install
equipment in compliance with national and local electrical codes. Standard equipment is supplied with
NEMA 4, 4X electrical enclosures and is not intended
for installation in hazardous environments.
Never perform electrical service on the dryer unless
the main power supply has been disconnected. Parts
of the control circuit may remain energized when the
power switch is turned off.
WARNING—Hazard or unsafe practice which could
result in severe injury or death.
CAUTION—Hazard or unsafe practice which could result
in minor injury or in product or property damage.
The dryer data plate, attached to the electrical control
box, contains critical safety and identification information. If the data plate is missing or defaced, immediately
contact your local distributor for a replacement.
2.0 Receiving, Storing, and Moving
2.1 Receiving and Inspection
This shipment has been thoroughly checked, packed
and inspected before leaving our plant. It was received
in good condition by the carrier and was so acknowledged.
Immediately upon receipt, thoroughly inspect for visible
loss or damage that may have occurred during shipping.
If this shipment shows evidence of loss or damage at
time of delivery to you, insist that a notation of this loss or
damage be made on the delivery receipt by the carrier’s
agent. Otherwise no claim can be enforced against the
carrier.
Also check for concealed loss or damage. When a shipment has been delivered to you in apparent good order,
but concealed damage is found upon unpacking, notify
the carrier immediately and insist on his agent inspecting
the shipment. The carrier will not consider any claim for
loss or damage unless an inspection has been made. If
you give the carrier a clear receipt for goods that have
been damaged or lost in transit, you do so at your own
risk and expense. Concealed damage claims are not our
responsibility as our terms are F.O.B. point of shipment.
Shipping damage is not covered by the dryer warranty.
4. Air treated by this equipment may not be suitable
for breathing without further purification. Refer to
OSHA standard 1910.134 for the requirements for
breathing quality air.
5. Certain parts of the dryer are not insulated and may
become hot during normal operation of the dryer. Do
not touch any of these areas without first determining
the surface temperature.
6. Use only genuine replacement parts from the manufacturer. The manufacturer bears no responsibility for
hazards caused by the use of unauthorized parts.
Safety instructions in this manual are boldfaced for
emphasis. The signal words DANGER, WARNING and CAUTION are used to indicate hazard seriousness levels
as follows:
2
2.2 Storing
Store the dryer indoors to prevent damage to any electrical or mechanical components. All packaging material
should be left in place until the dryer is in position.
2.3 Handling
The dryer is designed to be moved by means of the shipping skid or the base channels. The dryer may also have
lifting lugs for use with an overhead crane. Be sure to
attach all of the lift points and use appropriate spreader
bars to prevent damage to the dryer.
CAUTION — Never lift the dryer by attaching hooks
or slings to the piping, or to any part other than the
lifting lugs. Severe structural damage could occur.
3.0 Description
3.1 Function
Blower purge type regenerative dryers are an economical and reliable way to dry compressed air to dew points
below the freezing point of water. Desiccant dryers lower
the dew point of compressed air by adsorbing the water
vapor present in the compressed air onto the surface of
the desiccant. Adsorption continues until equilibrium is
reached between the partial pressure of the water vapor
in the air and that on the surface of the desiccant.
systems supplied by a lubricated air compressor, use a
High Efficiency Oil Removal Filter. A coarser filter will
be required upstream of the Oil Removal Filter if heavy
liquid or solid loads are present.
To ensure downstream air purity (prevent desiccant dust
from traveling downstream) adequate filtration downstream of the dryer is required. A High Temperature
Afterfilter, typically rated at 450°F (232°C) operating
temperature and capable of removing all desiccant
fines 1 micron and larger should be installed at the dryer
outlet.
These dryers continuously dry compressed air by using
two identical towers, each containing a desiccant bed.
While one tower is on-stream drying, the other tower is
off-stream being regenerated (reactivated, i.e. dried out).
The towers are alternated on- and off-stream so that dry
desiccant is always in contact with the wet compressed
air. In this way a continuous supply of dry air downstream
of the dryer is possible. The switching from one tower
to the other is controlled by a solid-state controller on
either a fixed time basis (standard) or a demand basis
(optional).
When a tower is placed off-line, it is slowly depressurized and the desiccant is regenerated. First, a blower
draws in ambient air which is heated. The heated air
flows through the desiccant bed, desorbs the moisture
from the desiccant, and carries the desorbed water out
of the dryer. The blower and heater are turned off when
the desiccant bed is fully heated. When configured for
cooling, a portion of the dry compressed air is diverted
from the main air flow and throttled to near atmospheric
pressure. This extremely dry, low pressure air passes
through the hot off-line tower, partially cooling the desiccant bed and reducing the dew point spike after tower
change over. At the end of the cooling stage, the tower
is repressurized to full line pressure. This prevents desiccant bed movement and downstream pressure loss when
the tower goes back on-line.
4.0 Installation
4.1 System Arrangement
Install the dryer downstream of an aftercooler, separator,
receiver, and high-efficiency oil-removing filter(s) so that
the dryer inlet air is between 40°F (4.4°C) and 120°F
(49°C) and contains no liquid water or oil. Liquid water
and/or inlet air temperatures above 100°F (37.8°C) can
reduce drying capacity. Contact your local distributor
for information on proper dryer sizing at elevated inlet
air temperatures.
Adequate filtration is required upstream of the dryer in
order to protect the desiccant bed from liquid and solid
contamination. Use an Air Line Filter in systems supplied by a non-lubricated (oil-free) air compressor. In
DANGER — This dryer must be fitted with a high
efficiency coalescing filter and liquid drainer that is
maintained properly. Failure to do so could result
in an in-line fire.
WARNING — The afterfilter, if installed, must be rated
for 450°F (232°C).
4.2 Ambient Air Temperature
Locate the dryer under cover in an area where the ambient air temperature will remain between 35°F (2°C) and
120°F (49°C).
NOTE: If dryer is installed in ambients below 35°F
(2°C), low ambient protection requiring heat tracing
and insulation of the prefilter bowls, auto drains and/
or sumps, and lower piping with inlet switching and
purge/repressurization valves is necessary to prevent
condensate from freezing. If installing heat tracing, observe electrical class code requirements for type of duty
specified. Purge mufflers and their relief mechanisms
must be kept clear from snow and ice buildup that could
prevent proper discharge of compressed air.
4.3 Location and Clearance
Install the dryer on a level pad. Ensure the dryer is
level by grouting or shimming as necessary. Holes are
provided in the dryer base members for floor anchors.
Securely anchor the dryer frame to the floor. Allow 24
inches clearance on all sides of the dryer for servicing. Provide adequate clearance for prefilter element,
afterfilter element and heater element replacement.
Provide protection for the dryer if it is installed where
heavy vehicles or similar portable equipment is likely to
cause damage.
4.4 Piping and Connections
All external piping must be supplied by the user unless
otherwise specified. Refer to Figure 2 for connection
sizes. Inlet and outlet isolation valves and a vent valve
are recommended so the dryer can be isolated and
depressurized for servicing. The connections and pipe
fittings must be rated for or exceed the maximum operating pressure given on the dryer nameplate and must
be in accordance with industry-wide codes. Be sure all
piping is supported. Do not allow the weight of any piping to bear on the dryer or filters. Piping should be the
same size as or larger than the dryer connection. Piping
smaller than the dryer connections will cause high pressure drop and reduce drying capacity.
If the purge exhaust piping must be extended outside the
dryer area, choose a combination of diameters, lengths,
and turns that limits the additional pressure drop to 1/4
psid or less. BACK PRESSURE WILL CAUSE DRYER MALFUNCTION. Consult the factory for piping details
if required.
WARNING — Do not operate dryer without installed
mufflers. Exhausting compressed air directly to
atmosphere will result in noise levels above OSHA
permissible levels and rapidly expanding gas could
potentially cause harm to persons or property.
Dryer bypass piping may be installed to allow uninterrupted airflow during servicing. If the downstream application cannot tolerate unprocessed air for short periods,
install a second dryer in the bypass line.
CAUTION — Do not hydrostatically test the piping
with the dryer in the system. The desiccant will be
damaged if saturated with water.
4.5 Electrical Connections
WARNING — These procedures require entering
gaining access to the dryer’s electrical enclosure(s).
All electrical work must be performed by a qualified
electrical technician.
Connect the proper power supply to the dryer according
to the electrical drawings in the back of this manual. Be
sure to follow all applicable electrical codes.
NOTE: A disconnect switch is not provided as standard
equipment and therefore, must be supplied by the customer.
Dry contacts (voltage free) are provided in the low tension electrical enclosure for a remote alarm. The contact
ratings are shown on the electrical drawing.
Connections to voltage-free common alarm contacts
with a minimum 5-amp rating can be made at terminals
TB4-1 through 3.
• Terminal TB4-3 is the common alarm connection.
• Terminal TB4-1 is the N.O.. (normally open) contact
connection.
• Terminal TB4-2 is the N.C. (normally closed) contact
connection.
• The alarm relay coil is energized when power is
supplied to the controller input terminals and there
is no alarms.
• The coil is de-energized when power is removed or
when an alarm condition exists.
NOTE: Before turning high voltage on to the dryer, an
ohmic test should be performed on the heater elements
to insure they are dry before proceeding with start-up.
This should be done after extended shut downs and long
delays between delivery and start-up. Connect one lead
of a megger to an unpainted surface of the control panel
or dryer frame. Connect the other lead to each phase
on the load side of the contactor. Adjust the megger to
the 1500 volt setting. Perform the ohmic test on each
zone of the heaters. A minimum value of 500k ohms
must be obtained.
CAUTION - Failure to ohmic test heaters after extended periods may cause heater failure.
4.5.1 RS-232 Connections
RS-232 connections can be made at the 3-pin connector
labeled J3 and located at the upper left-handed corner
of the control board. A cable for this connection can be
purchased through your distributor.
4.6 Initial Desiccant Charge
Blower purge type regenerative dryers use activated
alumina as the desiccant in the dryer towers.
Models 500 through 1050 are shipped with activated
alumina (1/8” bead) in the dryer towers. Desiccant is
shipped loose with all other standard models.
4
All desiccant shipped loose must be added to the
dryer chambers before the dryer is put into service
Refer to TABLE 1, DESICCANT REQUIREMENTS for
desiccant type and quantity per tower.
TO ADD DESICCANT
WARNING — The following procedure provides instructions for adding the initial desiccant to the towers. If replacing desiccant, refer to the “Procedure
for Desiccant Charge Replacement” in Section 7.0.
1. Verify pressure gauges of both towers indicate
0 psig. If not, depressurize the towers according to
the shutdown instructions in Section 6.
2. Remove the pipe plug or fill port flange cover (where
applicable) from the desiccant fill port at the top of
each tower. Refer to Figure 3 for the fill port location.
CAUTION – Pouring desiccant creates a fine dust;
safety goggles, gloves and a dust mask should be
worn by personnel installing desiccant. Refer to the
Material Safety Data Sheet that accompanies desiccant shipped loose for more complete information.
CAUTION – Do not tamp the desiccant in the towers.
Tamping damages desiccant and causes dusting.
3. Refer to Table 1 for desiccant quantity per tower.
When using Table 1 you will find the desiccant quan-
tities listed in layers. Each layer will vary in depth
due to the type, quantity and purpose of the desiccant. Layer 1 must be installed first at the bottom of
the vessel followed by layer number 2 etc., until the
complete charge of desiccant has been installed.
TABLE 1
DESICCANT REQUIREMENTS
(Quantity per Tower)
Layer
Model
500
600
750
900
1050
1300
1500
1800
2200
2600
3200
3600
4300
* AA = Activated Alumina
** TS = Tabular Support
123
354#
1/8” bead AA
453#
1/8” bead AA*
590#
1/8” bead AA
590#
1/8” bead AA*
710#
1/8” bead AA
48#
1/4” bead AA*
92#
1/4” bead AA*
92#
1/4” bead AA*
161#
1/4” bead AA
161#
1/4” bead AA*
258#
1/4” bead AA*
258#
1/4” bead AA*
719#
1/2” bead TS**
1/8” bead AA*
1/8” bead AA*
1/8” bead AA*
1/8” bead AA*
1/8” bead AA*
1/8” bead AA*
1/8” bead AA*
1/4” bead AA*
——
——
——
——
——
876#
1167#
1167#
1706#
1706#
2119#
2353#
146#
1/8” bead AA*
—
—
—
—
—
—
—
2679#
4. Utilizing an appropriate sized funnel, fill each desiccant tower as follows:
a. Install the required quantity of tabular support or
activated alumina in layer 1 of each tower.
b. Level layer 1 and each subsequent layer of desic-
cant as added to each chamber.
c. Finish filling each tower with desiccant until all
desiccant has been installed. LIGHT tapping
on the tower sides with a soft-face mallet should
yield additional free space to allow installation of
all desiccant required. DO NOT TAMP OR RAM DESICCANT.
5. Clean the fill port closure. Replace the fill plug using
Teflon tape or another pipe thread sealant suitable
for compressed air service. Reinstall fill port flange
cover (where applicable) in each desiccant tower.
The following instrumentation helps in monitoring dryer
operation and performance. Instruments which are
available as options are so noted.
Blower Purge Air dryers are rated NEMA 4 and include
the following:
• Solid State Controls
• Chamber Pressure Gauges
• Purge Flow Pressure Gauge
• Energy Management (Option A)
• Energy Management System & Dew Point Transmitter
(Option B)
5.1 Controls
The solid-st ate dr yer co ntro ls are locat ed in a
polycarbonate, NEMA Class 4/4X, IP66 rated electrical
enclosure mounted to a center panel located between
the two desiccant towers. Control features include:
• 15 LED’s to indicate operating status and fault
conditions.
5.5 Dew Point Transmitter
This option monitors and displays outlet pressure dew
points and provides an alarm signal if the dew point
exceeds user-specified set point. Recommen ded
calibration interval is 12 months. Contact the service
department for details.
Operation – The dew point is measured at the dryer
operating pressure and is displayed in the operator
interface. If the dew point is outside of the temperature
range, the display will indicate an over-range (high
dew point) or under-range (low dew point) condition. A
defective sensor assembly or an electronics malfunction
could also cause the transmitter to indicate underrange.
• Two line text display to provide status and diagnostic
messages.
• Upon power loss, dryer “fails safe” (inlet valve
remains in position). On power recovery, controller
resumes where power was lost.
5.2 Chamber Pressure Gauges
A gauge mounted on the gauge panel indicates which
chamber is on-stream and which is regenerating. The
gauge for the onstream tower indicates operating
pressure; the gauge for the regenerating tower indicates
0 psig.
5.3 Purge Flow Pressure Gauge
A gauge mounted on the gauge panel of the dryer
indicates purge air pressure.
5.4 Energy Management System
Th e opt ional Energy Manag ement System (EMS)
automatically adjusts dryer operation to compensate
for changes in operating conditions. Air samples are
continuou sly taken from the on-stream to wer and
passed ov er a moisture probe which sense s both
temperature and relative humidity. The moisture content
of the air within the desiccant bed is then precisely
determined. The on-stream tower will not depressurize
and regenerate until a predetermined set point has been
reached. This elimination of unnecessary regeneration
reduce s energy cons ump tion and e xte nds d ryer
desiccant and component life.
8
RS232
P1
P2
PURGE INLET
CHECK VALVE
TOP VIEW
ASME RELIEF VALVE
OUTLET CHECK VALVE
DESICCANT
FILL PORT
LEFT TOWER
PRESSURE GAUGE
PRESSURE REGULATOR
& PILOT AIR FILTER
DEWPOINTER
(OPTIONAL)
TOWER PURG
E
EXHAUST VALVE
FRONT VIEW
TOWER
DEPRESS VALV
E
DESICCANT
DRAIN POR
T
TO
WER
INSULATION
(OPTIONAL
)
CONTRO
L
ENCLOSURE
HIGH TENSIO
N
ENCLOSURE
RIGHT TOWER
PRESSURE GA
UGE
PURGE
PRESSURE GAUGE
REPRESS VALV
E
HEATER TEMP
THERMOCOUPLE
(CENTER END IN PIPE)
(OPPOSITE SIDE)
HEATER OVERTEMP RTD
PURGE
HEATER WITH
INSULATION
PURGE SUCTION
FILTER SILENCER
PURGE BLOWER
AND MOTOR
REAR VIEW
TOWER INLET
VALV
E
ASME CODE TAG
HOT PIPE INSULATION
P1P
2
P3
P4
TOWER BLOWDOWN VALVE
General Layout Drawing
Figure 3
(Models 500 through 600)
9
LEFT TOWER PURGE
EXHAUST VALVE
DEWPOINTE
R
(OPTIONAL)
PRESSURE REGULATOR
& PILOT AIR FILTER
LEFT TOWER
PRESSURE GAUGE
DESICCANT
FILL PORT
LEFT OUTLET
CHECK VALV
E
PURG
E
PRESSURE GAUGE
RIGHT TOWER
PRESSURE GAUGE
CONTROL ENCLOSURE
HIGH TENSION ENCLOSUR
E
TOWER INSULATION
(OPTIONAL)
DESICCANT
DRAIN PORT
RIGHT TOWE
R
DEPRESS VALV
E
ASME RELIEF VALV
E
REPRESS VALV
E
TOP VIEW
FRONT VIEW
PURGE
HEATER WITH
INSULATIO
N
PURGE SUCTION
FILTER SILENCER
PURGE BLOWER
AND MOTO
R
REAR VIEW
LEFT TOWER
INLET VALV
E
ASME CO
DE TAG
LEFT PURGE INLE
T
CHECK VALV
E
HOT PIPE INSULATION
AIR
OUTLET
AIR
INLET
LEFT TOWER
DEPRESS VALV
E
RIGHT TOWER PURGE
EXHAUST VALV
E
RIGHT OUTLET
CHECK VALV
E
AIR
OUTLET
AIR
INLET
LEFT TOWER
PURGE EXHAUST
VALV
E
PURGE EXHAUST
RIGHT TOWE
R
PURGE EXHAUST
VALV
E
PURGE EXHAUST
TOWER BLOW
-
DOWN VALV
E
HEATER TEMP
THERMOCOUPLE
(CENTER END IN PIPE)
(OPPOSITE SIDE)
HEATER OVERTEMP RT
D
10
General Layout Drawing
(Models 750 through 2600)
Figure 3a
TOP VIEW
OUTLET
CHECK VALV
E
ASME RELIEF VALV
E
DESICCANT
FILL PORT
LEFT TOWER
PRESSURE GAUGE
PRESSURE REGULATOR
& PILOT AIR FILTER
DEWPOINTE
R
(OPTIONAL)
TOWER PURGE
EXHAUST VALV
E
FRONT VIEW
TOWER
DEPRESS VALVE
DESICCANT
DRAIN PORT
TOWER INSULATION
(OPTIONAL)
HIGH TENSION
ENCLOSUR
E
CONTROL
ENCLOSUR
E
RIGHT TOWER
PRESSURE GAUGE
PURGE PRESSUR
E
GAUGE
REPRESS
VALV
E
PURGE BLOWER
AND MOTO
R
PURGE BLOWER
THROTTLING VALV
E
PURGE SUCTION
FILTER SILENCER
PURGE HEATER
WITH INSULATION
HEATER
OVERTEMP RT
D
HOT PIPE
INSULATIO
N
PURGE INLET
CHECK VALV
E
TOWE
R
INLET VALV
E
REAR VIEW
HEATER TEMP
THERMOCOUPLE
(CENTER END IN PIPE
)
(OPPOSITE SIDE
)
CHAMBER
BLOW-DOWN
VALV
E
Figure 3b
General Layout Drawing
(Models 3200 through 4300)
11
6.0 Operation
6.1 Controls
A solid-state controller controls valve and heater operation, monitors all critical operating conditions, and indicates operating status on a 2-line LCD display operator
interface. The controller receives input data from pressure switches, temperature sensors and the operator
interface. The operator interface displays information
about the dryer operating status and is used to change
the dryer operating mode.
6.2 Operating Modes
6.2.1 Automatic and Manual Advance
The drying and regeneration cycles are divided into
discrete steps. The operator selects either one of the
automatic advance modes (Energy Management, Dew
Point Control, or Fixed Cycle) or manual advance mode
(Test Cycle) through the operator interface.
Selecting any of the automatic advance modes enables
a timer in the controller to advance the program step-bystep according to the programmed schedule.
Setting up the controller for manual advance disables the
timer and the operator can advance the program one step
at a time. This mode is used for diagnostic purposes.
6.2.2 Fixed, Energy Management or Dew Point
Control Operation
The operator interface is used to select either Fixed,
Energy Management or Dew Point Control operation. In
Fixed Cycle operation, each tower is on-line (drying) for a
fixed time period regardless of the operating conditions.
In Energy Management or Dew Point Control operation,
a tower remains on-line until the desiccant bed has been
fully utilized. For lower than designed moisture loads,
this results in longer drying cycles, longer time between
regenerations and, therefore lower energy consumption.
Energy Management or Dew Point Control operation
are optional features.
6.3 Operating Sequence Description
1. Left Tower Drying – Right Tower Regenerating
At the start of the Left Tower Drying cycle, Left Inlet
Valve V1 opens, Right Inlet Valve V2 closes to isolate the two towers. Wet, compressed air flows up
through the left tower where it is dried. The dry air
exits the dryer through the Left Outlet Check Valve
V7.
Next, the Right Depressurization Valve V10 is
opened and the right tower is slowly depressurized.
Air exits through exhaust muffler M2.
After the right tower has depressurized, the Right
Purge Valve V4 is opened and the Blower M and
Heater H1 are energized. The heated air flows
through the Right Purge Check Valve V6, down
through the right tower, and exits through the Right
Purge Valve V4. The Blower intake air is filtered
to keep dust and dirt from entering the dryer. The
Blower M and Heater H1 are de-energized when
the temperature at the bottom of the right tower,
as sensed by the Right Tower Temperature Sensor
RTD2, reaches the Heat Termination set point. This
indicates that the bed has been fully heated.
Note: Blower will continue to run briefly at the end
of the Heating Step to sweep residual heat from the
heater.
The Repressurization Valve V11 is opened. A portion
of the dry air from the left tower now flows through
Repressurization Valve V11. This air is throttled to
near atmospheric pressure by Repressurization/
Sweep Orifice O2. The dry, low pressure air flows
down through the right tower cooling the desiccant
bed, and exits through the Right Tower Purge Exhaust Valve V4.
The Cooling Step continues until:
a) the right tower bed temperature falls to 150°F
or,
b) it is time to repressurize the right tower,
whichever occurs first.
Note: In fixed cycle, the bed will normally be partially
cooled because the repressurization step will occur
before the bed temperature can fall to 150°F.
Note: In Energy Management or Dew Point Control,
as the drying time extends beyond 4 hours, additional
cooling time becomes available thus the cooling
step will frequently terminate based on temperature
providing complete bed cooling.
At the end of the Cooling Step, the Right Tower Purge
Exhaust Valve V4 is closed. The right tower slowly
repressurizes to full line pressure and is ready to go
back on-line.
Note: Bed cooling can be disabled by moving JP4
to the “ON” position.
2. Right Tower Drying – Left Tower Regenerating
At the start of the Right Tower Drying cycle, Right
Inlet Valve V2 opens, Left Inlet Valve V1 closes to
isolate the two towers. Wet, compressed air flows
up through the right tower where it is dried. The dry
air exits the dryer through the Right Outlet Check
Valve V8.
Next, the Left Depressurization Valve V9 is opened
and the left tower is slowly depressurized. Air exits
through exhaust muffler M1.
12
WET GAS
INLET
DRY GA
S
OUTLET
SOL 'D'
V1
SOL 'F'
M1
V9
RTD
1
V3
V4
V2
SOL 'B
'
M2
SOL 'A
'
SOL 'G'
V1
0
RTD
2
V6
1PS
(RTD4/HS1)
ENERGY MGMT OPTION
SET @ 176°F
DRYING
EXH.
3PS
SET
@
5 PSIG
SOL 'C'
2
1
3
LEFT
TOWER
SET
@
45 PSI
G
M
RTD
3
SET @ 650°F
1T
C
SET @ 370°F
V5
2P
S
SET @ 176°F
4P
S
SET
@
5 PSI
G
REGE
N
SET
@
45 PSIG
SET AT
100 PSIG
RIGH
T
TOWE
R
V8
V12V13
SOL 'E'
V7V11
RV
1
SET @ 165 PSI
G
DEWPOINTER OPTION
DP
A
SOLENOID VA
LVES 'B', 'D', & 'G' ARE SHOWN ENERGIZED,
SYMBOLS ARE PER ANSI Y32.10 "GRAPHIC SYMBOLS FOR FLUID POWER DIAGRAMS."
SOLENOID VA
LVES 'A', 'C', 'E', & 'F' ARE SHOWN DE-ENERGIZED.
AS SHOWN FLOW DIRECTION IS:
INDICATES OPTION
3.
2.
1.
PILOT GAS LINE
RIGHT CHAMBER REGEN
LEFT CHAMBER DRYING
NOTES
4.
BD2BD1
H1
PI3
PI1
PI2
F1
PR&G
F2
O2
V1
4
O1
Figure 4
Sequence of Operation — Fixed Cycle Operation
Left Chamber Drying – Right Chamber Regenerating (shown)
(continued on next page)
13
After the left tower has depressurized, the Left Purge
P
EM
S
LEFT
TOWER
RIGHT
TOWER
Valve V3 is opened and the Blower M and Heater
H1 are energized. The heated air flows through the
Left Purge Check Valve V5, down through the left
tower, and exits through the Left Purge Valve V3.
The Blower intake air is filtered to keep dust and dirt
from entering the dryer. The Blower M and Heater
H1 are de-energized when the temperature at the
bottom of the left tower, as sensed by the Left Tower
Temperature Sensor RTD1, reaches the Heat Termination set point. This indicates that the bed has
been fully heated.
The Repressurization Valve V11 is opened. A portion
of the dry air from the right tower now flows through
Repressurization Valve V11. This air is throttled to
near atmospheric pressure by Repressurization/
Sweep Orifice O1. The dry, low pressure air flows
down through the left tower cooling the desiccant
bed, and exits through the Left Tower Purge Exhaust
Valve V3.
The Cooling Step continues until:
a) the left tower bed temperature falls to 150°F
or,
b) it is time to repressurize the left tower,
whichever occurs first.
6.3.1 Energy Management Control (optional)
Operation of the Energy Management Control cycle is
identical to the fixed cycle except the cycle is extended
until the desiccant bed in the on-line tower has been fully
utilized. The off-line tower is regenerated and remains
in a stand-by mode after being repressurized.
Figure 5 shows the air sampling system for the Energy
Management System – EMS option. A 3-way pilot valve
directs an air sample from the drying tower to the EMS
sensor. The EMS sensor detects the relative humidity
and temperature of the air sample. The air sample then
exhausts to atmosphere. The drying tower remains online until the moisture front arrives at the sensor.
Note: In fixed cycle, the bed will normally be partially
cooled because the repressurization step will occur
before the bed temperature can fall to 150°F.
Note: In Energy Management or Dew Point Control,
as the drying time extends beyond 4 hours, additional
cooling time becomes available thus the cooling
step will frequently terminate based on temperature
providing complete bed cooling.
At the end of the Cooling Step, the Left Tower Purge
Exhaust Valve V3 is closed. The left tower slowly
repressurizes to full line pressure and is ready to go
back on-line.
Note: Bed cooling can be disabled by moving JP4
to the “ON” position.
Figure 5
Optional Moisture Sensing
Energy Management System (EMS)
14
Loading...
+ 30 hidden pages
You need points to download manuals.
1 point = 1 manual.
You can buy points or you can get point for every manual you upload.