Fiber Filter

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Chilli Peppers

February 22, 2000

Some plants and factories pay a municipal sewer surcharge based on the quantity of suspended solids in the wastewater from the plant. We have worked with food processors, plastic recyclers and even a paper recycle mill that operate on this basis.

Usually these plants filter their wastewater with conventional devises such as either static (sidehill) screens or rotary drum screens (internal and external feed). Adding a Fiber Filter to remove further solids from the filtrate from these screens can have a quick payback.

One successful operation is at Gilroy Foods in Las Cruces, New Mexico. This ConAgra plant processes and dries chili peppers in order to produce powder and flakes used as food flavoring ingredients. Both red and green chili peppers are processed during a harvesting season that runs from July into November.

The typical wastewater flow is 200 gpm, well within the range of a Model FF-12 Fiber Filter. The inbound suspended solids will range from negligible to 1% or 2%. During the most recent season use of a Fiber Filter cut in half the total suspended solids measured by the city. This success as resulted in a commitment to rent another Fiber Filter during the next harvest.

The sludge from the Fiber Filter is trucked, along with static screen tailings and other solid waste, to landfill. (If a screw press were being used on solid waste, the Fiber Filter sludge would be fed to such a press.)

It is notable that this plant also rents a Model KP-10 press each year. It is used to dewater skins from blanched green peppers. This raw material is obtained from nearby green pepper canners. The press cake is dried to produce powder that is used to blend color and taste into the red chili peppers.

Issue 102

Deinking

July 13, 1999

Deinking Mills are a major specialty among paper recycling mills. The principal raw material categories for these mills are newsprint, magazines, telephone directories, and mixed office waste. There are many sub-specialties. For example, some mills will recycle only newsprint, while others will mix magazines with newsprint. This adds fiber strength and brightness, but it requires the addition of equipment to screen ash from the furnish. (Ash is mostly the kaolin clay coating used in glossy magazine paper.) MOW (Mixed Office Waste) mills use the least expensive material; however, it requires special equipment for removing a broad range of contaminants such as Styrofoam and stickies (contact cement).

The common feature of deinking mills is that they must separate printers' ink from the fiber. This is made difficult because the objective of ink formulators is to produce a product that stays bound to the paper fibers. Obviously there are many types of ink: water based, latex, those that work on ground wood paper, those that work for glossy coated paper, etc. One of the worst is laser printer ink, because it is heat bound to the fibers.

Once the ink and ash have been separated from the fibers, these contaminants must be screened from the flow. Traditional technology is to use a machine similar to a belt press for that purpose. The performance of these deinking machines is principally measured by (a) the brightness of the good fiber that is accepted, and (b) the amount of good fiber going in the reject steam.

Last year a Fiber Filter machine was tested for deinking capability. This was done in the laboratory of Thermo Black Clawson, the premier manufacturer of recycle paper mill machinery. The results were extremely encouraging. Compared to the conventional equipment, the Fiber Filter scored higher in brightness and, simultaneously, higher in fiber recovery. This means that more ink went through the fabric sleeve while at the same time that less good fiber was getting through the same sleeve. Ash separation was also excellent.

Feed consistencies ranging from 0.25% to 2.0% were tested. Accept consistencies were in the range of 7.5% to 14% solids, with flow rates of 150 to 250 gpm in the Model FF-12.

Issue 96

Dilute Flow Filtration

June 25, 1999

Recently we tested the Fiber Filter at Liberty Paper in Becker, Minnesota. This is a modern OCC (Old Corrugated Container) recycle mill. Rated at 300 tons per day, the mill specializes in producing linerboard. The test machine was a FF-6, the smaller version of the FF-12 machine that would be required to satisfy the mill loading.

We were working with dilute feed flows, .02% to 0.20% solids consistency, and remarkable success was experienced. The results broaden the market for Fiber Filters from deinking to include most recycle paper mills.

The applications tested were (a) filtering press liquor from Vincent screw presses that are used on the mill wastewater stream; (b) filtering the flow of wastewater ahead of the clarifier; and (c) filtering the final wastewater flow that goes into the city sewer system.

Feed:  Press Liquor from Vincent VP-16's screw presses.  These are used on the mill wastewater stream after it has been across sidehill screens.
          Feed:          .06% consistency      620 ppm TSS *
          Filtrate:      .02% consistency      330 ppm TSS *
          Cake/Sludge:  3.0% consistency

Clarifier Feed Chest
          This includes sidehill screen filtrate, press liquor, and other waste streams.
          Feed:          .15% consistency   1,970 ppm TSS *
          Filtrate:      .04% consistency     460 ppm TSS *
          Cake/Sludge:  4.1% consistency

These two tests were run with an 86 micron sleeve in the FF-6, very high elevation adjustment, 30 to 60 gpm, no VFD.

* The differences between percent solids consistency and parts per million of total suspended solids arise from using two different laboratory procedures for measuring the same thing.

We also ran tests on the city sewer flow. The results were surprising:

City Sewer Water:

    • Feed: 204 ppm
    • Filtrate: 148 ppm

This test was run with a 43 micron sleeve, very high elevation adjustment, 90 to 120 gpm. Their normal flow is 400 gpm, so a FF-12 may carry it all with a 31 micron screen. The cake/sludge we collected had sand and grit, with some fiber.

The cake/sludge from the Fiber Filter would be fed back into the screw presses.

Two alternate projects are being reviewed for potential financial justification:

    • Filtration of clarifier feed so as to reduce polymer consumption in the clarifier.
    • Filtration of final flow to the city sewer so as to reduce sewer surcharges.


Issue 95


Fiber Filter Operating Hints

INSTALLATION

The Fiber Filter may tend to vibrate, so for a permanent installation you will want to anchor all the feet of the machine to supporting structure.

Note that, since the angle of inclination to be adjusted, flexible hoses must be used for the inlet flow and, possibly, the filtrate flow.  Be sure to allow enough hose length for full travel of the tilting mechanism without interferences.

Changing the filter sleeve assembly is required periodically.  To accomplish this, convenient floor space must be left at the sludge discharge end of the machine.

Operating the optional sleeve flushing mechanism requires space at the drive end of the Fiber Filter so that the flush liquid supply hose and tube can move in and out.

The filtrate flow can be allowed to empty into a tank or collection pan mounted under the machine.  (Such a pan is useful to the operator for detecting a torn filter sleeve.)

It is important that provision be made to immediately shut off the flow of liquid going into the Fiber Filter in the event that the drive motor is stopped or trips out.  The inbound flow going into the Fiber Filter will purge through the sludge discharge chute if the rotor stops turning.  Provision should be made for this eventuality.

It is best to make provision to by-pass both part and all of the inbound flow to the Fiber Filter.

Spill containment is a consideration.

 

RIGGING

The Fiber Filter may have a lifting eye that is positioned at the top of the machine, near the center of gravity; a chain can be slung through this hole for lifting.  Alternatively the machine can be lifted from below with a forklift.

 

START-UP

Before putting power to the Fiber Filter, the rotor should be turned by hand to make sure that it turns freely.  This can be done by taking the cover off the end of the motor and turning the cooling fan by hand.  Also, it can be done by reaching through the sludge discharge chute to grip and turn the rotor.  Be sure the motor starter is locked out when performing this procedure.

The rotor of the Fiber Filter turns in a counter-clockwise direction, when viewed from the drive end of the machine.

Be sure that the spring tension is set correctly tight prior to start up. 

 

INSTRUMENTATION

In almost all cases satisfactory operating conditions can be achieved by adjusting the elevation of the Fiber Filter.  However in some cases, driving the Fiber Filter with a Variable Frequency Drive can be useful in optimizing performance.  The use of a VFD can be valuable during initial start-up for establishing the best pulley ratio for future fixed speed operation (if a belt drive is used).

A useful instrument for testing a Fiber Filter is an ammeter.  This is particularly true if there are high concentrations of solids in the flow to the Fiber Filter.

 

SPRING TENSION

The Vincent Fiber Filter features an External Fabric Tensioner.  These springs can be adjusted with the machine in operation.  Usually spring tension is adjusted only once after initial stretch has occurred in a new sleeve.

The effect of spring adjustment on capacity and filtration is minimal.  However, tight spring adjustment is vital for achieving long sleeve life.  The fabric must be kept taught; otherwise it will flutter and fail in a few days.

On the Models FF-12 and FF-30, the springs have a free length of 6".  These should be compressed 1", to 5" length, for proper tension on the fabric sleeves.  In the case of the FF-6, the springs are 4" long and they should be compressed to 2-1/2" length.  (Some FF-6 machines have 6" orange springs; these should be compressed to 5-1/2".)

 

FF-6 TIGHTENED TO 5-1/2" FF-12/30 TIGHTENED TO 5
FF-6 TIGHTENED TO 5-1/2"   FF-12/30 TIGHTENED TO 5"

The springs will normally stretch out by 3/8" to 3/4" during initial operation of the Fiber Filter.  The spring compression should be re-set after this occurs.

 

OPERATION

The Fiber Filter separates a flow containing dilute solids into a stream of filtrate and sludge.  This sludge will be quite wet; however, it will contain the majority of the insoluble (fiber) solids.  The Fiber Filter is not a press, so it does not separate the solids into a cake.  When starting with a clean, empty Fiber Filter, it can take several minutes for the first sludge to appear at the discharge.  This is because the fabric sleeves can hold up to five minutes worth of sludge.

With a very dilute feed, one would expect around 95% of the flow fed to the Fiber Filter to come out as filtrate and 5% as sludge.  This can vary significantly in applications where there is high solids consistency in the feed to the Fiber Filter.

If excessive vibration or high motor amps are evident, it is likely that the solids are not discharging from the sleeve.  This can be remedied by either (a) lowering the elevation angle of the machine or (b) increasing the flow of liquid into the machine.  (It can also be an indication that sludge has bridged and is accumulating in the sludge discharge spout.)

In some applications the operation of the Fiber Filter is cyclical.  The operating cycle can range from a few seconds up to two minutes.  The cycle starts with a longer period of minor vibration and minimum solids (sludge) discharge.  This is followed by a shorter period of stronger vibration and a heavy discharge of sludge.  This occurs with a constant, uniform inbound flow and a steady discharge of filtered liquid.

It must be anticipated that the Fiber Filter may purge.  Under this condition the inbound flow will discharge, unfiltered, through the sludge discharge chute.  This condition will occur if the electrical power to the Fiber Filter is interrupted without the inbound flow being shut off.  It can also occur if the sleeve becomes blinded (coated over); if the elevation angle is too low; or if inbound flow conditions change.

The Fiber Filter will overload and trip out if excessive solids accumulate within the sleeves.  This occurs if there is insufficient liquid flow through the machine.  The condition can be avoided by reducing the angle of inclination of the Fiber Filter.  The overload condition will occur either if the machine is set to operate with a thick inbound flow and this flow is significantly reduced, or if the solids content of the inbound flow is significantly increased, without lowering the angle of inclination.  Alternate rotor configurations are available that avoid this problem.

fiber filter fiber filter
STEEP INCLINATION   LOW LEVEL INCLINATION

Excessive splashing of liquid from the sludge discharge chute is corrected by backflushing the sleeves, by increasing the angle of elevation, or by reducing the inbound flow (gpm).

The rotor of the Fiber Filter turns in a counter-clockwise direction, when viewed from the drive end of the machine. 

However, it has been found that operation in the reverse direction, with certain rotor designs, may produce improved results.  Reverse operation may be appropriate if excessive splashing of liquid from the sludge discharge chute occurs.  Try this before you give up.

 

VARIABLES

The five variables, in order of importance, that affect Fiber Filter operation are:

  • FEEDING:  Volume of inbound flow;
  • INCLINATION:  Angle of inclination of the rotor;
  • SLEEVES:  Mesh of the fabric sleeves; and
  • BACKFLUSH:  Cleanliness of the fabric sleeves;
  • RPM:  Rotational speed of the rotor.

This assumes that solids consistency in the inbound flow is not a controllable variable.

 

FEEDING

Fiber Filters require that the feed to the machine be at a constant flow rate.  The feed must be at low pressure.  Good performance of the Fiber Filter can be achieved by gravity feeding from above.  An overflow line can be used to maintain constant head and flow.

The Fiber Filter can also be fed by pumping a flow directly into the machine.  A variable speed pump, especially a diaphragm pump, works best.  A regulating type valve, such as a globe valve, may be required to adjust the inbound flow.

 

INCLINATION

The principal adjustment of the Fiber Filter is made by changing the angle of inclination.  In general, with a steeper angle, greater dewatering is achieved.  Usually greater throughput capacities can be achieved with a more gentle angle.  The fluttering cycle and vibration intensity are also affected.

If the angle of inclination is too great, or if the inbound flow is too little, it is possible that no sludge will be produced.  In this situation the suspended solids in the flow are being disintegrated and beaten through the sleeves by the action of the rotor.  This condition is normally accompanied by mild to severe fluttering of the sleeves.

Not uncommonly, with certain rotor designs it will be necessary to aim the Fiber Filter downward, with the discharge below the horizontal.  This occurs with either very thick flows or very low gpm flows.  It occurs when there is not enough liquid present to flush the slurry/sludge from the Fiber Filter.  (It may be necessary to place a block under the elevation pivots or the feet of the machine in order to achieve a downward angle.)

If the angle of inclination is too high for a given flow, or if the inbound flow is too low, the fabric sleeve will fill with solids.  This can lead to severe fluttering of the fabric, and the Fiber Filter may trip out on electrical overload or the sleeves may fail.

 

FABRIC SLEEVES

The fabric sleeves of the Fiber Filter are made of tweed woven monofilament fabric.  The synthetic polymer fabric is selected according to a rating of micron size.  In addition, the fabric is selected for its rating in terms of tensile strength (circumferential as well as axial) and chemical and temperature resistance.

Standard polyester sleeves are good to 220o F and are resistant to both caustic and acid cleaning solutions.  PEEK sleeves are good for 350o F. 

Micron ratings of 20 to 190 are typical.  These relate to the size of the particle that will pass through the sleeve, not to the passage size through the filaments of the fabric.

The following chart lists common sleeves:

Micron Rating Air Perm Mesh Nominal Opening Material
RLX 572 80 0.007" 0.190 mm Polyester
155 260 100 0.006" 0.150 mm PEEK
132 299 110 0.005" 0.118 mm Polyester
118 501 120 0.005" 0.118 mm Polyester
86 234 170 0.0035" 0.086 mm Polyester
50 72 270 0.002" 0.050 mm Polyester
43 208 325 0.002" 0.045 mm PEEK
31 39 500 0.001" 0.030 mm Polyester
20 24   0.0008" 0.020 mm Polyester
12 19   0.0005" 0.012 mm PEEK

PEEK sleeves are seven times stronger that polyester, but cost twice as much.  This fabric is more chemical resistant, also.

The sleeves quiver while the Fiber Filter is in operation.  This action keeps the sleeve from blinding.  A quivering action is normal and will result in very long sleeve life.  Fluttering, on the other hand, reduces sleeve life.  It ultimately results in the failure of the fabric.  Replacement is simple.

 

BACKFLUSH SYSTEM

In certain applications the fabric sleeve of the Fiber Filter may become blinded with usage.  This may be corrected by using the backflush system.  The frequency at which this is necessary varies considerably: it can be as often as twenty times an hour.  Or, operation once a shift or once a day may be all that is required.

Some sanitary applications require that the machine be flushed for CIP purposes.  This is done with the backflush system. 

This backflush system consists of an internal spray rings with nozzles directed to spray the outside of the fabric sleeves.  The spray ring is moved back and forth inside the Fiber Filter either by hand or by an air cylinder mounted on the outside.  A booster pump is included to increase the pressure of the spray fluid.  A canister filter is included to prevent plugging the spray nozzles.  A control panel is included that allows setting the frequency and duration of the spray cycle.

The backflush system is designed to operate with 200 to 250 psi at the nozzles.  It can be operated with or without the rotor in operation, and with or without flow through the machine.  The preferable mode is with the machine in normal operation (full flow through the machine at normal rotor rpm).

Backflush fluid can be water or CIP solution.  In some cases it is necessary to use chemical cleaners such as caustic or acid in addition to a water flush cycle.

 

RPM:  FIBER FILTER SPEED

Optimal operation of the Fiber Filter is almost alwaus achieved by adjusting the elevation.  With consistent material being fed to the machine, especially with an elevated tank for gravity feed, constant speed should be perfectly adequate.  In a few cases superior performance may be achieved by driving the unit with a Variable Frequency Drive (VFD).  In such case the Fiber Filter speed (rpm) can be set later by changing drive sheaves (if a belt drive is used).

In general, higher speed results in higher throughput capacity.  It can also result in splashing of wet material from the discharge and reduced solids concentration in the sludge/slurry discharge.  High speed operation increases the power draw of the motor.

In applications involving filtration of a variety of solutions, or inconsistent inbound flow, the Fiber Filter is best equipped with a VFD.

 

SLEEVE LIFE

The most common sleeve failure is a tearing at the hem.  The second most common is a failure of the seam.  These failures generally occur because the machine is allowed to operate with the fabric in a fluttering condition.  When this occurs the machine will be seen to vibrate, and rattling noise will be heard from the spray rings inside the machine.

To prevent fluttering: 

  1. Be sure the springs are quite tight (not loose).
  2. Lower the inclination so that wetter sludge is produced. 
  3. Increase the flow into the machine so that solids do not accumulate inside.
  4. Switch to a heavier, preferably PEEK, fabric sleeve.

 

CAPACITY MEASUREMENT

The best way to measure capacity of a Fiber Filter is to collect timed samples of filtered liquid and discharge sludge.  Allowing the filtered liquid to accumulate in a tank, and measuring the change in depth over time, works well.  Similarly, a 5-gallon pail is suitable for collecting discharge sludge.

 

PERFORMANCE MEASUREMENT

For a quick performance measurement of the Fiber Filter it is convenient to collect samples of inbound and filtered liquid.  These should be equal size samples (one fluid ounce is typical).  These samples are poured into the center of a piece of cotton cloth; making a ball and twisting the cloth will force the liquid through the cloth.  The fiber will remain on the cloth, allowing a visual comparison between inbound and outbound.

Similarly, samples of inbound and outbound liquid can be collected in Imhoff cones or jars and allowed to settle.  The differences noted give an idea as to the effectiveness of the machine.

Use of a laboratory centrifuge on inbound and outbound samples permits a more quantitative measurement of performance.  Similarly, oven drying of filter samples permits a quantitative analysis of suspended (insoluble) solids.  If the fluid being filtered contains dissolved solids (sugars), the samples should be washed to zero Brix as part of the testing procedure.

 

SLEEVE CLEANING

In some sanitary applications it is necessary to remove the filter sleeve assembly from the Fiber Filter and soak it in a cleaning solution such as caustic.  This may have the benefit of shrinking the fiber back to a taught condition, depending on the fabric material being used.  Purchase of a spare sleeve assembly is recommended for this type of operation.

 

SHUT-DOWN

When shutting down the Fiber Filter, the sleeve assembly should be cleaned.  If practical, this should be done by admitting fresh water to the inlet of the machine. 

Also, the backflush system should be used.  This is done by leaving the machine in operation (rotor spinning) but with no flow being admitted.  It will help to lower the angle of inclination of the Fiber Filter.  Operate the back flush system to clean the fabric sleeves.  This will prevent solids either from overloading the machine on start-up or from crusting on the fabric.

 

SLEEVE FAILURE DETECTION

A metal screen can be installed over the filtrate drain in the barrel of the Fiber Filter.  Should a sleeve fail, fiber will blank over this screen and cause liquid to drain from the discharge head, alerting an operator.  This type of screen is illustrated below.

screen failure detection fiber filter alert fiber filter screen

 

LUBRICATION

There are up to four grease lubrication fittings on the Fiber Filter.  These are on the shaft seal housing and flanged bearing at the inlet as well as the shaft seal housing and flanged bearing in the discharge head.  Normal bearing grease is suitable for the shaft seals. 

 

FABRIC SLEEVE REPLACEMENT

The most important item in changing a fabric sleeve is to note that the seam is either a lap or double hook joint.  Arrows are printed on the sleeves to denote the direction in which the rotor should go past (sweep over) the joint (seam).

The arrows assure that the seam is installed so that the waves of liquid sweep over the blunt edge of the seam, not against it.  That is, sleeves should be installed so that the blunt edge of the lap joint is not facing into the waves of liquid that are pulsed by the rotor.  While it is harder to visualize, the same effect is true with the double hook seams. 

If the sleeve is installed the other way around, the wave of liquid created by the moving rotor paddle will hit an edge of fabric.  This leads to early seam failure.  This is true although there may be a film adhesive, which laps over the joint of fabric in a smooth manner.

It is important to take a few extra minutes when changing a sleeve.  The seam should be straight with the main axis of the machine; the two hems should be uniform, without any pinches; there should be no dips or ripples in the fabric surface.

To properly install a new sleeve, first position it reasonably uniformly and clamp it tight.  Next, slightly tension the sleeve temporarily with the tensioning springs.  This will make evident any non-uniformly tensioned areas.  Loosen the sleeve clamp at one end and tap it so as to pull the fabric tight; then re-tighten the sleeve clamp.

The location of the seam of each sleeve should be noted.  Most commonly the seam is placed where it can be seen through the inspection door.

Safety tip:  when inspecting sleeves with the machine in operation care must be taken.  There is a natural tendency to poke a finger through a suspected hole.  If this is done with the machine in operation, the rotor will surely sever the finger.

 

REMOVING AND RE-INSTALLING THE FABRIC SLEEVE ASSEMBLY

To remove the assembly that holds the fabric sleeves, first shut off the flow into the Fiber Filter and then lock out the machine.  It will help to operate the backflush system before disassembly.  Set the level of the rotor at an attitude, most generally the horizontal position, which will be convenient for removing the discharge head and sleeve assembly. 

An Allen head wrench is used to loosen the setscrews (usually four) that hold the inner race of the bearing that is mounted to the discharge head. 

At this point, there are two options:  (1) The springs can be left in place and the entire discharge head and sleeve assembly can be removed as one piece, or (2) the springs can be removed, followed by the discharge head.  Once this is done, the sleeve assembly can be slipped out of the barrel of the Fiber Filter. 

Note that the discharge bearing comes off with the head; there is no need to loosen the four bolts which hold the bearing.

Axial rails support the sleeve assembly.  The inlet end slides over a spout ring in the inlet head of the machine.

Look through the open end of the sleeve assembly to make sure the fabric is not dragged or pushed into the rotor.  Do this during both disassembly and re-assembly operations.

Following re-assembly and tightening the springs of the Fiber Filter, check the fabric sleeves through the inspection panels.  This should be done before putting power to the machine, as a loose sleeve will become entangled in the rotor.

 

ROTOR CONFIGURATION

Several rotor designs are available for Vincent Fiber Filters.  Most designs have straight paddles with ribbon flighting added to direct fiber toward the discharge.  Contrary to normal screw conveyor logic, a tight pitch ribbon flight is used to move large quantities of solids, while a long pitch ribbon flight is used when the solids flow is minimal.  Switching to a long pitch rotor can reduce excessive water being present in the discharge sludge.

 

ROTOR INSTALLATION

The rotor is supported by two spherical self-aligning roller bearings.  These are mounted at the drive end and on the discharge head. 

Special care must be taken when re-installing a rotor.  The drive end of the rotor must be slipped through the shaft seal housing.  To do this properly, remove the seal housing and insert the end of the rotor through the hole in the inlet head.  The rotor should be pushed in just far enough that the seal housing can be slipped onto the end of the shaft.  Then the rotor shaft can be pushed through the drive-end bearing until the thrust shoulder on the rotor shaft seats against the bearing.  The seals can be damaged if the seal housing is not loosened during rotor installation.

Care must be taken that the rotor spins freely after assembly.  Rarely, this may require relocating one or both of the two main bearings.  Both of these bearings are self-aligning.  The rotor shaft should not ride heavily on the seal housing when assembly and alignment are complete.

 

SHAFT SEALS

Fiber Filters use Johns Manville JM Clipper lip seals.  These are the c-cup style.  There will be a pair in the housing at the drive (inlet) end of the machine, mounted on the inlet head.  These seals have internal springs to hold the lip against the shaft. 

 

BACKFLUSH SYSTEM

Most Fiber Filters are supplied with a backflush system.  This consists of a pressure boosting pump, a solenoid valve to open the water line when the pump is in operation, a filter for filtering the flush water, and a control panel.  The control panel has a timer with two clocks:  the top clock sets the time interval between flushings, and the lower clock sets the time duration that the pump will run during the flush cycle.  There is also a solenoid valve which supplies air to the air cylinder which is used to move the spray ring assembly along the length of the sleeves.

fiber filter

 

REPLACEMENT PARTS

The most common wear parts in the Fiber Filter are the sleeves, the sleeve clamps, the seals, and the bearings.  These are stocked by Vincent.  Be sure to specify the Serial Number of your machine when ordering replacement parts.  The seals and bearings, like the sheaves and belts, are standard OEM components that can be purchased from the original equipment manufacturer (OEM).  The specification of these items is included in the O&M Manual.

 

SAFETY

These Operating Hints have left unstated the obvious safety hazard:  a Fiber Filter, like any rotating machine, is unforgiving.  If clothing or limb gets caught in the rotor it will not stop until damage has been done.

The easiest way to get hurt with a Fiber Filter is to reach inside the sludge discharge while the machine is operating.  There has already been one minor injury as a result of this, so do no let yourself become the second.

A second way to get hurt is to press your hand or finger against the fabric sleeve while the rotor is in operation.  If you push your finger through a hole, the rotor will cut off the finger.

The use of common sense is all that is required.

 

Robert Johnston, P.E.

fiber filter parts list

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Fiber Filter Patent

November 20, 2000

Here at Vincent we are proud of the award on September 12, 2000 of United States Patent number 6,117,321. It describes an EXTERNAL TENSION ADJUSTMENT DEVICE FOR A FILTERING SLEEVE IN A FILTERING MACHINE. This came as a result of our work over the last three years with the Fiber Filter.

This is a machine design feature used in all Vincent Fiber Filter machines. The Fiber Filter works on the principle of inducing high frequency vibration in a fabric sleeve that is stretched with springs. The patent covers mounting the sleeve tensioning springs on the outside of the machine.

Prior technology used tensioning springs that are mounted on the inside of the machine. The primary disadvantage of this arrangement is in filtering food products where it fundamentally less sanitary to have springs in the flow of filtrate.

An additional advantage is that the tension of external springs can be adjusted with the machine in operation.

Only twenty months elapsed between the application and issue dates. This speedy action can be attributed in part to the fact that a law firm was not used in the process. The initial disallowance of the patent claim was resolved by telephone, without the requirement of any correspondence.

A copy of the patent is available upon request.

Issue 111

Fiber Filter for Pectin Recovery

July 26, 2005

An interesting application for the Fiber Filter has evolved over the last few years. The project started as a rental at a plant whose wastewater treatment plant (WWTP) was causing excessive odor.

The customer's operation involves receiving fresh lemon peel as a raw material, washing the dissolved solids (sugars) from the peel, and then extracting pectin from the washed peel. The precipitated pectin is dried and sold, in powder form, as a food ingredient.

The WWTP load came principally from the dirty water from the peel washing system. This water contains both dissolved solids and suspended particles of lemon peel. The initial project involved using a Model FF-12, with coarse 190 micron sleeves, to filter this wastewater.

The project was a success. Odor from the WWTP noticeably decreased after filtering out the suspended solids. This is true even though most of the solids are dissolved, so they pass through the Fiber Filter.

At first, the solids sludge from the Fiber Filter were trucked to a remote site. Soon, however, it was determined that this sludge contained valuable pectin of good quality.

For the next season, a second Fiber Filter was added, and the sludge from the machines was pumped back to the peel wash system. In this manner the pectin was recovered.

Today, a third Fiber Filter has been added. The system has been further refined by pumping the sludge from the three machines directly to the acid/alcohol plant. There it is mixed with the washed peel, and the pectin is extracted. (They found that if this sludge was added back to the washing system, the screw presses did not seem to work correctly.)

Issue 163

 

 

Maximizing Capture Rate

September 18, 2002

The unique fine filtration and capture rate characteristics of the Vincent Fiber Filter have resulted in successful operation in pineapple juice and paper mill shower water applications. The same principle is used in both these two very different installations.

The Fiber Filter separates a sludge of fiber from the flow admitted into the filter machine. Usually the goal is to produce a firm, bulky sludge in order to (a) maximize yield of filtrate and (b) facilitate handling of the sludge.

In other applications the goal is to maximize the capture rate. That is, the need is to have as high as possible a percentage of suspended solids captured in the sludge discharge. Usually this is achieved by simply installing filter sleeves with smaller micron openings. However, because tighter weave fabric results in lower gpm capacity, this is not always practical - nor necessary.

Another way of achieving high solids capture in a Fiber Filter is to reduce the consistency of the solids in the sludge discharge. Reducing the elevation angle of Fiber Filter, other things remaining constant, will result in a watery sludge discharge, along with a higher capture rate.

In the case of pineapple mill juice, excessive wear and poor capacity was being experienced with a centrifuge that is used to filter the juice. A Fiber Filter was added in series, ahead of the centrifuge. This Model FF-12 sees a feed of 100 to 120 gpm, and 118 and 190 micron sleeves are used. Filtrate from this Fiber Filter now goes to the centrifuge. Increased centrifuge capacity and decreased maintenance have been achieved.

The elevation of the Fiber Filter is kept low, resulting in a low consistency sludge discharge of about 5 to 10 gpm. This flow, which contains the majority of the suspended solids, is sent to a decanter. This decanter works well in separating good juice from the sludge.

The second similar application is in filtering shower water used on a paper machine. This shower water keeps the paper machine clean so that the sheet of paper forms and separates, at high speed, without blemishes or tearing. Trash material cannot be conveyed to the paper machine in the shower water, nor should particles large enough to plug the nozzles be present.

In practice it was found that a milkshake-thick 0.5 gpm flow of sludge could be produced by the Fiber Filter. This was with 31 micron sleeves and flow of 200 gpm, with 70 ppm suspended solids in the feed flow. By reducing the elevation, the sludge discharge jumped to 5 gpm. The important part was that the capture rate improved, with the solids in the filtrate dropping from 30 to 18 ppm. The change in waste discharge, from 0.5 to 5 gpm, is insignificant in the overall operation of a paper mill.

Issue 131

Meat Flavor Extracts

July 11, 2001

Ariaki U.S.A., a Virginia firm, has been running a new oil recovery system. The elements of the installation include a Model KP-16 screw press, the press liquor from which flows directly into a Model FF-6 Fiber Filter. Waste materials from the plant are run through the system in order to recover oils.

Ariaki produces meat flavored extracts from by-products that are acquired from hog, broiler, beef and turkey slaughter houses. These materials are processed in extractors to recover food grade meat flavorings. The waste material from the extractors resembles hot stew.

In the past this waste has been turned over to a rendering company for disposal. It has had little value because of the high moisture content.

The new system recovers oil from the extractor waste flow. This is done by pumping the waste to the Vincent screw press where a thick liquid is expelled through the screen. The liquid is high in both oil content and suspended solids.

This flow of press liquor, about 5 gpm, drains from the screw press to a Fiber Filter that is mounted directly below. The Fiber Filter, using a coarse fabric sleeve, removes suspended solids from the flow. These solids, along with the cake from the screw press, fall to a waste hauling trailer that is parked below the Vincent machines. (The system may be modified so that the sludge from the Fiber Filter can be pumped back to the inlet of the screw press.)

The filtered press liquor is pumped to heating tanks where the oil is recovered. Water separated from the oil is treated in the Ariaki wastewater treatment plant.

It is notable that the material pumped to the screw press has chunks of bone. These range in size from a dime to pieces that cannot be covered by a fifty cents piece. They are pumped with a V-Ram piston pump to the screw press. These bone fragments pass through the press without difficulty.

Issue 118

Peach Cannery

September 20, 2000

A lead from the 1999 IEFP (International Exposition of Food Equipment) show led to the placement of a Model FF-12 Fiber Filter at the Del Monte peach cannery in Kingsburg, California.  This eighty-year-old cannery operates during a three month season each year.

Wastewater from the plant is used to irrigate a sorghum field a few miles away.  An environmental problem existed because suspended solids from the wastewater formed deposits in the field.

The suspended solids come from the peach peeling operation.  Caustic peelers are used, with a continuous cycle to reuse the peel water.  Make-up water is adjusted so that approximately 300 gpm flows to the waste water stream.

This wastewater is filtered in rotary drum screens.  In order to maximize solids capture, screens with very fine slots are used.  However, even with wedgewire with 0.012" slot widths excessive suspended solids were present in the filtrate water.

The Fiber Filter was installed in series with the rotary drum screens, in the final filtering position.  Dramatic improvement in solids removal was evident even with coarse 190 micron sleeves in the Fiber Filter.  Since there was excess capacity in the Fiber Filter, a switch was made to finer 86 micron sleeves.

The Fiber Filter was supplied with an automatic spray ring feature.  This is used to back-flush the filter sleeves.  A booster pump was provided to increase the spray water to 200 psi.  A timer control panel assures fully automatic, continuous operation.  The timer was set to backflush every six to ten minutes.

The sludge (peel and some pits) from the Fiber Filter is landfilled.

It is notable that the wastewater contains a significant amount of dissolved solids.  These measured 2o Brix.  Naturally these dissolved solids cannot be captured in a filter, so they go to the spray field.  Fortunately they are an acceptable environmental condition.

2013 Note:   Use of the Fiber Filter was discontinued when the plant's wastewater treatment facility was expanded.

See photos below.

NOTE SLUDGE FALLING FROM DISCHARGE CHUTE NOTE ROTARY DRUM SCREENS IN BACKGROUND 

NOTE SLUDGE FALLING FROM DISCHARGE CHUTE             

NOTE ROTARY DRUM SCREENS IN BACKGROUND

 

Issue 112

 

 

Shower Water Filtration

October 25, 2001

Tests were recently conducted using a Vincent Fiber Filter on shower water at Atlantic Packaging in Scarboro, Ontario. The Fiber Filter was selected because of its small footprint and attractive capital cost compared to conventional filters.

This recycle paper mill has a combination OCC (Old Corrugated Container) and tissue operations. The most important use of shower water is on the felt of paper machines. Other applications are on trommel and rotary drum screens.

The primary source of shower water comes from disc strainers used at the end of the stock prep process. The disc strainers raise the paper pulp from 1.2% to 12% consistency. There are three effluents: cloudy, clear, and super clear. The cloudy effluent is pumped back to the start of the process at the hydrapulpers. The clear effluent is re-used half way back in the stock prep process, with the excess going to sewer.

The disc filter itself uses some of the super clear; the rest is filtered prior to use as shower water. The existing super clear water filters are Sweco machines that feature a vertical axis with a spinning drum screen. The drums have fabric panels backed up with coarse mesh steel screen. The drums are about 4' in diameter.

These Sweco's are very old and have served their purpose; maintenance expense has become excessive. Thus our Fiber Filter is being evaluated as a potential replacement.

The very low solids consistency of the super clear water resulted in high capacity in the Fiber Filter even with very fine fabric sleeves. With a feed consistency of 70 ppm, using a 31 micron sleeve, we were able to produce filtrate with 20 to 25 ppm. This was done with the Model FF-12 being fed about 200 gpm and producing about 1 gpm of fiber-sludge discharge.

A goal of the project is to eliminate the need for addition of city water make-up to the shower water tank.

There is a rule-of-thumb used in selecting filters used on flows ahead of spray nozzles: The filter basket should have openings one tenth the size of the openings of the shower nozzles. This is achieved with the 20 and 31 microns sleeves available for use with the Fiber Filter machines.

Issue 122