GENERAL: The proper design and construction of the foundation, sump, piping, pumps and
other ancillary equipment operated with the Press are the responsibilities of the owner, engineer or contractor unless arranged otherwise at the time of purchase. These instructions are intended as a guide based on sites with configurations similar to those recommended by Aspen. Since they are general, some modifications may be required to solve your unique requirements. Should assistance be required, please contact Aspen’s Service Department.


1.1: Study applicable plans to verify location of press. Confirm the machine orientation in this manual matches the hook up locations in the plans including wash water connection, wash water valve handles, chicane handles, electrical power, sludge feed and polymer feed.

1.2: Verify cast in place anchor bolt locations from the General Arrangement Drawings. If anchor bolts are expansion anchors, they will be installed after press is set on piers.

1.3: Lift press according to Handling Instructions and carefully set it in place.

CAUTION: Ensure lifting safety is observed during all hoisting operations

1.4: Loosely secure anchor bolts. If expansion anchors are to be used:

a. Mark their locations while press is in place.
b. Remove Press following Handling Instructions.
c. Drill and install expansion bolts.

Note: Drilling the anchor bolts while the Press is in place could damage the frame’s protective coating or cause alignment problems.

d. Replace the press following Handling Instructions.

e. Loosely secure the anchor bolts.

1.5: Level the Press:

a. Using a precision level, check across the frame to ensure the machine is level.

b. Shim the Press around the anchor bolts until all of the rollers are level.

Note: Do NOT shim any roller. Shimming the roller could cause premature bearing failures or belt alignment problems and void the Aspen warranty.

c. Tighten the anchor bolts.

1.6: Verify rollers remained level by checking the same rollers again.

Check machine for level lengthwise by taking an elevation at the four corners.

1.7: Re-level the machine as required.

1.8: Grout the machine as applicable using a non shrink, non metallic grout.

1.9: Connect Wash Water: Water should be provided to the wash boxes at 85 psi and the following flow rates:

One Meter, 40 gpm; One and One-Half Meter, 60 gpm; Two Meter, 80 gpm.

If equipped with the three belt option the water flow rates will be increased to 60, 90 and 120 gpm respectively. If the water pressure or flow is not sufficient for the above requirements, then a booster pump is required. The wash water connection will be a 1.5 inch diameter Schedule 80 PVC unless otherwise specified. Aspen recommends a ball valve be installed prior to any booster pump required and a pressure gauge be installed prior to the press to verify pressure requirements.

1.10: Connect Sludge Feed Line: The sludge feed line will be connected to the Press feed box as shown on the General Arrangement Drawing in this manual. Use a flexible connection to allow for adjustment of the feed box. The feed box is supplied with a standard ANSI 150 lb. raised face flange unless otherwise specified. The Two Meter Press has a six inch diameter feed inlet, and on all other sizes, a four inch diameter feed inlet will be supplied (standard, unless otherwise noted). Ensuring the sludge is fed evenly across the belt width is critical to the performance and maintenance of the belt press. Because of this, Aspen recommends eight feet of feed piping in the central vertical plane of the press prior to the feed box. The feed piping must be adequately supported prior to the connection to the press to not place external loads on the feed inlet assembly. The feed inlet assembly must be adjusted to be exactly level for proper press performance. Additionally, sharp turns in the feed line should be avoided by using long radius elbows.

1.11: Install In Line Mixer: In Line Mixer should be installed initially at the location that will allow 30 seconds retention time or as recommended by manufacturer’s process Engineers. Ensure the directional arrow on the mixer points in the direction of the sludge flow. The polymer injection ring must be installed between the inlet flange of the mixer and the sludge feed pipe. Connect the injection ring to the splitter manifold via four lengths of clear hose. Connect the splitter manifold to the polymer system according to the polymer system manufacturer's instructions. If the sludge feed piping is elevated above the mixer and polymer system a check valve should be installed at the inlet to the splitter manifold to prevent sludge back flowing into the polymer system when shut down. Contact Aspen Spare Parts to obtain the valve. See Section 14 for spare parts ordering information.

1.12: Electrical Hook-Ups: Electrical interconnection of the Press is always through a dedicated control panel. It is often the case that all required motor starters and or drives are integrated with the operating logic into a single panel. In this case, it will only be necessary to perform all interconnection wiring between the press and the panel as described by the terminal strip diagrams found in the as built control panel drawings.

(See Electrical Control Panel Portion of the O&M) It is also possible that the control panel may contain only operating logic and all starters are at a motor control center or that other equipment must be interlocked with this panel. Once again, the as built drawings will provide interconnection guidance. On the Press, all control wiring is terminated in the junction box on the machine. To complete the installation, the following connections are required:

WARNING: Electrical connections should only be attempted by a qualified electrician. All electrical work must be in compliance with NEC, NEMA, OSHA and other local codes. Serious personal injuries, fatalities or equipment damage could result from improper electrical connections.

1.13: Press Junction Box: The machine is shipped pre-wired. A wiring diagram is packed in the junction box. The installing contractor is responsible for interconnecting the junction box and the control panel as indicated on the as-built electrical drawings. Be certain to seal the conduit entry point to the junction box to prevent water entry. The conduit entry should always be in the bottom of the junction box when possible.

1.14: Press Drive Units: Consult the Drive Section of this manual for the electrical requirements of the specific drive motors provided. The connection will be made at the junction boxes on the drive motor.

1.15: Hydraulic Power Unit: The motor is a 1,200 rpm, 230/460 volt, 60 Hz, 3 phase, 1.0 horsepower unit unless otherwise indicated in the hydraulic unit section of this manual. Electrical connection will be at the motor junction box. The connection information is on the inside cover of this box. The hydraulic unit will also have one or two low pressure switches which have been pre wired to the press junction box.



2.1: Prior to attempting dewatering for the first time, the press must be inspected and prepared for operation. This section addresses the procedures which will prepare the machine for operation.


2.2: Visually inspect anchor bolts and verify they are tightened.

2.3: Verify the machine is level.
2.4: Inspect the rollers:

(a) Verify rollers are level across the machine width.

(b) Check for cleanliness. Remove any construction materials, packing materials, dirt, grease, etc.
(c) Turn each roller by hand two or three revolutions.

Note: The seals should drag slightly and the drive rollers should not turn.

(d) If any roller turns roughly or sticks, inspect the roller for external obstructions. If no obstructions exist, disassemble the bearing housings and inspect the bearings. If damaged, notify Aspen for repair or replacement.

(e) Inspect the roller coatings. All coatings should be intact.

2.5: Inspect the gravity drainage grids:

(a) Grids should be level and free from any sharp edges or protrusions.

(b) Grids should be free of embedded materials and all bolt heads should be well below plastic wear surface.
(c) Sludge restrainers should be in place and the rubber seal should be intact. Remove any sharp edges. Rubber seals will wear with use. As they wear, adjust them to maintain adequate sealing and if necessary replace them.
(d) Chicanes blades should be resting on the grids. No metal portion of the chicane assembly should be touching the grids.
(e) Verify the scrapers pivot freely and that the plastic blades are not chipped, cracked, or broken.

2.6 Inspect wash boxes and verify rubber seals are in place:

(a) The rubber seals located at the wash boxes will wear with use. As they wear, adjust them to maintain adequate sealing and if necessary replace them.


WARNING: Electrical connections should only be checked by a qualified electrician. Failure to follow federal, state or local codes could cause severe personal injuries, fatalities or severe equipment damage.

2.8: Hydraulic Power Unit: Bump the motor circuit to ensure motor is turning in the correct direction.

Caution: Ensure unit is filled with hydraulic fluid. Severe equipment damage could result if unit is operated without oil.

2.9: Drive Unit Inspection: Bump the drive unit circuit to ensure drive rollers turn in the correct directions.

Caution: Ensure gear box is drained to operating level before operating drive unit. Damage to the drive unit could occur if unit is operated before being drained to the correct level.

2.10: Wash Water Booster Pump: Bump the motor circuit to ensure motor is turning in the correct direction.

Caution: Ensure pump is primed or is self-priming. The pump could be damaged if operated without being primed.

2.11: Electrical Sensors: Inspect all sensors to ensure they shut down the appropriate machine functions. Depending on your particular installation, some of the following machine sensors and alarms may not be present. However, they are included as an indication of the full capability of the machine. When triggered, the sensors will cause the Press to have a total or a partial shut down as indicated below:

(a) Total Shut Down: All machine functions, sludge and polymer feed systems, hydraulic power unit and wash water system are stopped if not in the Bypass Mode. This results from the following alarm conditions:

(1) Belt Breakage: For each belt there is a proximity switch which detects a broken belt. (At left below)

(2) Belt Misalignment: There are two proximity switches which detect gross misalignment of the belts on either side. (At right above)

(3) Low Wash Water Pressure: a pressure switch which detects water pressure below the owner specified setting,
typically 60 psig. (Shown at right)

(4) Hydraulic Temperature: a temperature switch that detects hydraulic fluid temperature above 175°F at the hydraulic power unit.

(5) Hydraulic Pressure: pressure switches which detect hydraulic

pressure too low to maintain drive traction and belt alignment. (Shown at left; above and behind the pressure gauges)

(6) Emergency Stop: a push button on the machine and other optional location(s) to manually stop all functions. (Shown at right

(7) Emergency Trip Cord: a pull cord circling the machine which functions as an emergency stop.

(b) Partial Shut Down: shuts down sludge and polymer feed and continues to operate the belt drive, hydraulic power unit and wash water system for a period of one hour. This results from:

(1) High Sludge Level: a level sensor which detects sludge about to overflow the edge of restrainers in the gravity section.
(2) Lack of Cake: a level sensor which detects a lack of sludge in the gravity section.

Caution: Alarms and sensors are on the machine to protect personnel and the equipment. Operating the machine with sensors not functioning properly places the operator and equipment in danger.


2.13 Verify all hydraulic lines between hydraulic power unit and the Press are in place.

2.14 Put the control valves on the Press in the retract position.

If you have this style of extend/retract valve instead of the hydraulic manifold the tension for both belts will be set at the same time for both belts by turning the adjusting knob on the head of the hydraulic pump.

2.15 Energize the hydraulic power unit. The pump may take up to 90 seconds to reach full pressure which will register on the pressure gauge.

Note: If the pump has not picked up pressure within 90 seconds, turn off pump motor and check for correct pump rotation and fluid level.

2.16 With the pump operating, turn the regulator knob on the pump until the pressure is in the range of 300 to 350 psig. Lock the pressure regulator lock nut at this setting.

2.17 Adjust the upper belt tension by turning the knob on the pump head. Observe the gauge for the upper belt and set the pressure to around 350 psi.

2.18 Adjust the lower belt tension by turning the knob of the valve in the end of the manifold block. Observe the gauge for the lower belt and set the pressure to around 300 psi. By design, the lower belt tension pressure cannot be set higher than the upper belt tension.

2.19 Push in both control valve knobs on the manifold to extend the belt tensioning cylinders.

2.20 Check the belt press hydraulic power unit for leaks. Repair if required.

2.21 Cycle both rollers through the tension/retract cycle several times to ensure they function correctly and to purge air from the system.

2.22 Inspect steering sensing paddle for damage, and freedom of movement. If its movement is stiff, notify the

Aspen Service Department.

2.23 Manipulate the steering valve by manually moving the sensing paddle off center in one direction. The hydraulic positioning unit should move fully in one direction in response to the sensing paddle. Move the paddle off center in the other direction and note the movement of the hydraulic positioning unit in the other direction.

2.24 If equipped with the Nip Roller option, verify that both cylinders are operating correctly and uniformly to move the nip roller toward the bottom pressure roller. There must be a uniform space of 3/8 inch between the nip roller and the bottom pressure roller. The hydraulic pressure for the nip roller should be initially set at 100psi. The normal operating pressure range for the nip roller is from 100 to 350 psi.

3.0 WASH WATER: Inspect the following items:

3.1 Verify the wash water is being delivered to the wash boxes at 85 psig or higher and at the correct flow rates. If a booster pump is installed, ensure pump is functioning correctly.

3.2 Verify all valves in the water line are open.
3.3 Verify hand wheels on both wash tubes are fully closed. Rotate completely in the counter clockwise direction and then back fully in the clockwise direction. This action rotates the brush inside the wash tube and cleans the spray nozzles.

NOTE: Do NOT over tighten hand wheel. This could damage the internal seals causing a loss of wash water pressure. Should water continue to drain from the bypass hose it is likely that gravel or trash is preventing the valve from closing. In this case repeat the opening and closing cycle of the valve to clear it.

4.0 DEWATERING BELT INSTALLATION: The dewatering belt is one of the most easily damaged items on the Press. Because of this, it is important to know how to handle the belt prior to attempting installation.

4.1 Handling and Storage:

(a) Always store belts in their protective wrappers or containers standing on end.

(b) Do not smash, stack or store items on the rolled belts.
(c) Do not allow the belt to become kinked or folded.
(d) Keep foreign substances off the belts as much as possible.
(e) Never attempt to dewater sludge with a new belt before performing the run-in on the press as described in Section 7.7.

4.2Belt Safety: Installing belts on a new machine where there are no belts being replaced is a job that requires two people working together using much care and patience.

When old belts are being replaced it is acceptable to part the old belt and attach the new belt to the old at the clipper seam and then use the press drive at low speed to pull in the new belt while the old belt is fed out. 

To ensure safe operation observe the following:

(a) Stop Switches: Ensure location and operation of the stop switches for the drive and hydraulic unit are known and that all switches function properly
(b) Remember, even though the belt moves slowly it can catch clothing, hands, jewelry, etc. Remove jewelry and fasten clothes to protect yourself.
(c) The hydraulic system also moves slowly, but with bone crushing force. DO NOT ever place body parts between the moving machine parts.


Aspen Corp. has developed a belt installation tool that greatly simplifies the installation of belts on all types of belt filter presses. The amount of time and labor involved to install the belts is greatly reduced by the use of the Aspen Belt Installation Tool and the belt installation operation will also be safer.

The Aspen Belt Installation Tool comes in various widths to match the size of belts on your machine. The tool has a triangular shaped section of belt with a seam on its straight edge and there are two long straps attached to the opposite edge. The tool is used by attaching the seam of the tool to the seam of the new belt and pulling and guiding the belt into and through the belt filter press with the two long straps.

The Aspen Belt Installation Tool is most helpful when belts are being installed for the first time on a new press. When replacing worn belts on a press the new belt may be attached to the old belt and be pulled into the press while the old belt is fed out.

But, when the belt being replaced is damaged and cannot be used to install the new belt then the Aspen Belt Installation Tool may be used to great advantage. 

The Aspen Belt Installation Tool is made in 5 widths for all belt presses. 

Detailed Instruction for Use on a Type 94 (late model) Press

5.0 Belt Installation Instructions.

a. Install the lower belt first.

b. Place the new lower belt roll at the tension end of the Press with the cake (smooth) side up and the loose end toward the press.

Note: The smooth (flattened) side of the belt faces the sludge. Turn the rough side toward the rollers. The Aspen warranty does not cover belts that have been installed improperly.

c. Place the new upper belt roll at the discharge end of the Press with the cake (smooth) side up and the loose end toward the press.

d. The tension cylinders are to be retracted. Open the seals on the wash boxes and retract the scraper blades from the drive rollers. Retract the scraper blade from the upper tension roller. Raise the sludge restrainers on the gravity deck.

e. The rolled up belt should be supported on a pipe passed through the roll and supported on each end on jack stands or saw horses so the belt roll can turn freely.

f. Attach the Aspen Belt Installation Tool to the leading edge of the new lower belt using one seam wire.

g. Unroll enough of the lower belt to lift it up over the lower tension roller at the end of the press.

h. Thread the two straps down under the wedge plate, over the curved grid and under the perforated roller. Be careful to not leave any slack in the straps between the tool and the press. Both straps should be threaded through the machine with the same approximate tension.

i. Thread the two straps around the pressure rollers alternately over and under being sure to not skip any rollers.

j. Be sure the straps are on the roller about 6 to 12 inches from the end and not around the shafts on the ends.

k. After passing the straps over the drive roller pass the straps down under the lower steering roller and back through the lower wash box.

l. After the lower wash box pass the straps under the lower rear guide roller and then under the lower tension roller back to the point where you started.
m. The operator shall control the press drive while two assistants pull on the straps to guide the new lower belt into the press.

n. Run the press slowly and observe the belt tracking while it is being pulled into the press. It may be necessary to stop and guide the belt installation tool into the wash box to keep it from catching on the seals.

o. When the end of the belt emerges from under the lower tension roller, stop the press, remove the tool from the end of the belt and seam the ends of the new lower belt together with two seam wires.

p. Next attach the tool to the leading edge of the new upper belt and thread the straps through the upper wash box and down the length of the gravity deck. Be careful to not leave any slack in the straps between the tool and the press. Both straps should be threaded through the machine with the same approximate tension.

q. Thread the two straps between the upper tension roller and the scraper blade, down over the wedge plate, over the curved grid and under the perforated roller inside the lower belt that was just installed.

r. Important: Be sure the straps are next to the upper tension roller between the tension roller and the wedge scraper blade and do not run the straps for the upper belt installation under the wedge plate. Only the lower belt passes under the wedge plate.

s. Thread the two straps around the pressure rollers alternately over and under being sure to not skip any rollers. Place the straps between the lower belt and every other roller following the path of the lower belt with the straps on top of the belt.

t. Be sure the straps are on the rollers about 6 to 12 inches from the end and not around the shafts on the ends.

u. After passing the straps over the drive roller and under the scraper roller pass the straps upward and over the upper steering roller toward the upper wash box back to the point where you started with the new upper belt roll.

v. The operator shall control the press drive while two assistants pull on the straps to guide the new upper belt into the press.

w. Run the press slowly and observe the belt tracking while it is being pulled into the press. It may be necessary to stop and guide the belt installation tool into the wash box to keep it from catching on the seals.

x. When the end of the belt emerges from under the scraper roller at the discharge end of the press, stop the press, remove the tool from the end of the belt and seam the ends of the new upper belt together with two seam wires.

y. Finish the belt installation by adjusting the gravity deck sludge restrainers down against the upper belt and put the wash box seals and the upper tension roller scraper blade back in place.

5.1 Run-In Period: A new belt should always be broken in at low speed for about 30 minutes prior to being loaded with sludge. This ensures that the new belt will track properly and pre-stretches the belt. Always monitor the machine closely during this time.

The process for belt run in is:

NOTE: Never attempt dewatering until the new belt has been pre-stretched.

5.2 Adjust the tensioning pressure to 30 pli on both pressure dewatering belts. 7.7.2 Start the belt wash water flow and energize the belt drive.

5.3 Follow the chart below to increase the belt tension during the break in cycle.

First Hour 30 pli
Second Hour 40 pli
Third Hour 50 pli
Fourth Hour 40 pli

5.4 Set the belt tension to the desired setting for running the process stream. Generally, both belts will be operated at the same pli setting, not the same hydraulic pressure (psi). Tighten the jam nut on the pressure adjusting knobs when the desired belt tension has been set to prevent accidental changes due to vibration or other influence.5.5

5.5 Adjust the steering sensing paddle by moving the valve mounting bracket so the pressure dewatering belt tracks in the center of the machine.

Note: Fine adjustment of the steering circuit is best done with the belts moving.

CAUTION: Use extreme caution when working around the moving belt. Avoid loose clothing that might become caught in the belt.

5.6 To run in the independent gravity belt set the tension initially at the maximum setting. After 4 hours readjust to the proper operating setting. Check and readjust after the first week of operation.