VINCENT KP Series Assembly instructions

Vincent In our ninth decade
CORPORATION
August 16, 2014
OPERATING HINTS
SERIES KP PRESSES
SEE NOMENCLATURE DRAWING AT THE END OF THIS MANUAL
INDEX
RIGGING 3
INSTALLATION 3
INVERTER VFD & PLC CONTROL 4
VACUUM EFFECT 5
INSTRUMENTATION 6
START-UP 7
FEEDING 7
BUILDING A PLUG 8
PRE-THICKENING 9
AIR CYLINDER REGULATOR 9
DISCHARGE CONE 10
ROTATING CONE OPTION 13
INTERMITTENT OPERATION 13
DOUBLE PRESSING 14
MOISTURE CONTENT 14
COMPRESSION 15
PRESS SPEED (RPM) 16
CAPACITY MEASUREMENT 17
A-B-C-D PLATES 17
SCREW LIFE 18
2810 E. 5
th
Avenue, Tampa, Florida 33605
Phone: [phone] Fax: [phone]
E-mail: [e-mail]

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SCREW CONFIGURATION 19
PIE CUTTING 19
JAMMING 21
SCREEN BLINDING 22
CHANNELING 23
PURGING 23
BRIDGING 24
RESISTOR TEETH 24
FLUID INJECTION 25
CORD CUTTER AND STRIPPER 26
POLYMER 27
NOTCHES 27
WIPERS 27
PRESS AID 28
HYDRATED LIME, GYPSUM, AND ALUM 28
PRESS LIQUOR 29
SCREEN SELECTION 29
SCREW-TO-SCREEN CLEARANCE 31
DISCHARGE SPOUT 33
CONE BUSHING 33
WING FEEDERS 34
CLEANING 35
SCREEN REMOVAL 35
SHAFT SEAL 37
SCREW REMOVAL 37
SCREW REPLACEMENT 40
GEARBOX BASICS 40
PRESS LUBRICATION 41
REPLACEMENT PARTS 42
SAFETY 42
NOMENCLATURE 44

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OPERATING HINTS
SERIES KP PRESSES
RIGGING
Be sure to properly support the press when lifting it from the truck. Usually a sling
positioned under the inlet hopper, on the side closest to the gearbox, finds the
center of gravity. On big presses, do not lift just one end of the press, as it is
possible for the frame to deflect, shifting the screw within the press. Interference
between the screw and the screen can result.
INSTALLATION
Be careful to not to rack the press when tightening the mounting bolts. In the case
of large presses, do not just bolt or weld the press down to a level foundation!
Instead, first place the press where it is to be installed. Next, place shims between
the press frame and the steelwork (or floor, concrete pedestal or foundation) to fill
any gap where the press is to be anchored. Only after shimming (or grouting)
should the press be pulled down tight. Doing otherwise can rack the frame of the
press, and this can cause screw-to-screen interference.
A large press must be mounted solidly, preferably to a foundation or structural
steel. If a press draws its full rated horsepower without the press being anchored
to the floor, the frame of the press can twist.
For maintenance, the screw is removed through the cake discharge end of the
press. Allow the space required.
To suit individual conditions, a hollow bore gearbox can be rotated 180o, even 90o
either way. Consult the owner's manual or factory in these situations as it is likely
that the oil level in the gearbox will have to be adjusted.
Material can be fed into the press many ways. You may need to allow for return
feed of overflow material in the event that more is fed to the press than it can take.
Spill containment is a consideration which should be taken into account, because it
may be possible for un-pressed material to purge from the cake discharge of a press.
We recommend that a manual disconnect, for killing power to the motor, be installed close
to the press.

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When material is piped to a press in a closed piping system, it is important to have
a 2" vent line open to the atmosphere, along with an overflow return line. The vent
is necessary to prevent a siphon effect which can induce a vacuum in the inlet
hopper and reduce press capacity. The return line should empty above the surface
of the return pit. The overflow should fill less than half of the cross section of the
return line.
A variable frequency drive (VFD) programmed for either variable speed or auto-
reversing may be required, depending on the application. If not, the use of a
reversing starter switch is recommended; they cost only a little extra. Such a
switch is handy for clearing a jammed press.
It order to provide space for a cake take-away conveyor, the press can be installed
tilted with an elevated discharge.
Similarly, it is possible that, when operating intermittently with very wet material left
in the press between runs, the liquid may loosen the cake plug at the discharge.
This might cause the plug to blow out upon start-up. To minimize this condition,
the press can be installed with the discharge tilted upwards.
INVERTER VFD & PLC CONTROL
It is always recommended that an inverter VFD be used to start, protect, and
operate the screw press. With a VFD it is possible to establish the optimal
combination of screw speed and discharge cone air pressure. The VFD also can
be used to reverse the press in case of a jam or to slow it down during upset
conditions.
Nine presses out of ten will operate unattended, indefinitely, and just fine at line
frequency of 50 or 60 Hertz. If two screw presses are mounted in parallel, they are
usually fed with a screw conveyor which drops to fill the first press, with the rest
going to the second press; this is followed with a drop-out for overflow.
However, we need to address the exceptions:
Use of level controls is becoming more and more common. These are used to regulate
either the flow going into the press or to regulate the screw speed.
In some applications a press is sized for handling upset conditions of large flow,
while the normal flow is quite small. In these cases a level control is used, and the
PLC can be programmed to turn off the press when a low level is reached in the
inlet hopper, and the press re-started when a higher level is signaled.

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In some cases the press will tend to jam, overload, and trip out on high amps. In
this situation it may be necessary to program the controls so that the cone
automatically goes open on high amps, re-closing at a lower set point. This
arrangement requires a solenoid operated 4-way air valve, replacing the manual
valve which is provided with the press.
In other cases of jamming a simpler arrangement is to install a Cone Timer. A
timer is used to periodically open the cone. The closed period is determined by the
amount of time required for press cake to accumulate in the press. The duration of
the "cone open" period is long enough to dump most of the press cake that has
formed. This type of operation may be used if the press periodically experiences
jamming or overload due to fluctuations in the amount of material being fed into the
press. Alternatively, it may be used with slippery or slimy press cake that cannot
be dewatered to sufficient firmness to force the cone open. Cone Timer panels are
available from Vincent at no charge.
Some applications require the use of a specially programmed variable frequency
drive. In this case the VFD is not used to change the speed of the press, but,
rather to set it for auto-reversing operation. By having the screw run backwards for
three or four turns every few minutes, some difficult-to-dewater materials can be
pressed much more effectively. This operation can help a great deal with material
which tends to blind (cover over) the openings in the screen. Vincent has loaner
VFD's if you want to give it a try. The technique works well on bar screens; care
must be taken with perf screens so that the screw does not snag the screen during
the reverse cycle.
Once through start-up, the cone is almost always permanently left in the closed
position at whatever air pressure has been found to be effective. A plug of cake
will be left around the cone whenever the press is turned off; this will clear on its
own accord on restarting the press.
However, some materials may set up and become hard, or freeze, within the press
when the press in turned off. This is especially true in the case of pressing wet
coffee grounds or outdoor installations. For these applications it is advisable to
open the cone for a period of one minute before turning off the press. This allows
the press to partially empty itself, fluffing the material left in the press. Vincent can
provide information for automating this procedure.
VACUUM EFFECT
In some applications, increased screw press capacity can be obtained if the area
outside of the screen is under a vacuum. This can be achieved by mounting the

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press at a high elevation, with the press liquor drain line dropping below the
surface of a drain tank or pit.
That is, the drain line from the press should go below the surface of the pit or pond
into which it drains. If this line is relatively small in diameter and has a steady
downward slope, a vacuum will be induced around the screen of the screw press.
The mass and velocity of press liquor flowing through the drain line create this
vacuum. To draw air bubbles downwards with the press liquor, the velocity of the
fluid must be greater than five feet per second.
The cover over the screen of the press will have to be sealed, usually with Silicone.
The amount of vacuum is a function of the elevation between the press and the
drain pond. For good results, the press should be mounted on a stand that is 20'
tall or higher.
INSTRUMENTATION
The most useful instrument to have when testing a press is an ammeter. The load
drawn by the drive motor of the press is indicative of how much work the press is
doing. The higher the amps, the better the dewatering. Also, the higher the amps,
the closer the press is to jamming, and the greater is the abrasive wear. Very low
amps indicate little dewatering is being done; the screen is blinded; low
compression is taking place; or the flow into the press has stopped.
A moisture balance is valuable for measuring the moisture content of the inbound
material and of the press cake. If an oven is used to dry samples, be sure it is set
at 160oF or less if there are sugars in the sample. Samples should be left in the
oven overnight. The tare weight of the pan should be much less than the weight of
the sample which is being dried.
As mentioned previously, level controls can be useful in operating a press. With a
signal providing the depth of material in the inlet hopper, the speed of the press
can be varied to match the flow going into the press. With egg shells, a simpler
level control is used to only signal when a high level is reached; its signal will
increase the screw speed. In special cases the press can be turned off when a low
level is reached and re-started when a higher level is reached.
In the case of pressing liquids that contain dissolved sugars or salts, a
refractometer is valuable for assessing press performance. The Brix of the
inbound flow, the press cake, and the press liquor will all be the same figure. The
higher the Brix, the higher will be the solids content of the press cake.

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If dissolved (soluble) solids are present, the suspended (insoluble) solids (fiber) in
the press liquor are generally measured by filtering and washing a sample and
drying the filter paper in an oven. Dissolved solids will be washed from the sample
during the washing process.
START-UP
Before putting power to the screw press, it is advisable to bump the motor or even
rotate the screw by hand. This will prevent damage to the press in case tramp
material has been left in the press. Also, the screw may have shifted so as to hit
the screen. (Minor rubbing is normal; it will go away once there is material in the
press.) To turn the screw by hand, remove the fan guard on the motor and turn the
fan blades.
The screw of the press turns in a counterclockwise direction, when viewed from the
drive end of the press.
If problems are encountered, they are apt to be blinding, jamming, channeling or
purging. There is a section for each of these ahead in this manual.
FEEDING
Material can be fed into the press many ways. Commonly, screw conveyors,
pumps, transition chutes, pre-thickener screens or cyclone separators are used.
Consider making provision for return of overflow material, in the event that more is
fed to the press than it can take. Spill containment should be considered.
Sometimes either a static (sidehill or parabolic) or rotary drum screen (RDS) must
be mounted over the inlet hopper to prethicken the flow ahead of the press; the
tailings (solids) from the screen can be funneled into the press. This arrangement
is desirable when the feed to the press is dilute.
Also, material can be dropped from a shredder or cyclone separator into the press.
A shredder is used to increase capacity and dewatering in the case of low bulk
density materials like lettuce leaves, alfalfa, onion peel, and cornhusk, or to prevent
blockage.
Most commonly, the best screw press performance is achieved if the material in
the inlet hopper stays just at the top edge of the screw. Usually presses work best
with only atmospheric pressure in the inlet hopper. In order to minimize static

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head, press headboxes are kept short, and level controls are used to minimize the
depth.
When a pump is used to feed a press, the system can be either open or closed.
We recommend the open system where little or no pressure exists in the inlet
hopper, thus preventing the press from being force-fed. In this arrangement either
there is an open return line allowing flow back to the source feeding the press, or
level is controlled in the inlet hopper. It is best to have a line that allows material to
recirculate past the press inlet. This will prevent pressurizing the inlet of the press,
which can cause both blinding of the screen and purging from the cake discharge.
A port on the side of the inlet hopper is frequently provided on larger Vincent presses. It is
used to view the level of material over the screw. It has a bolted cover because it is rarely
used.
If a fluid is piped through a sealed cover which is bolted to the inlet hopper, force-
feeding is possible. A by-pass tee should be provided so that the pressure in the
inlet hopper is minimized. In addition, a 2" vent line, open to the atmosphere, must
be provided to prevent siphoning material in the inlet hopper out through the
recirculation line.
Inlet hopper pressure over one to four psi can force fibrous material against the
screen so as to blind off the screen, resulting in unsatisfactory performance.
At pressures above 10 to 15 psi in the inlet hopper, it is possible to blow the "plug"
of press cake that forms at the discharge of the press. Unscreened liquid will
purge from the cake discharge. Exercise caution if either hot or hazardous material
is being pumped into a press.
At inlet hopper pressures of 40 psi and above, the shaft seals will be blown out of
their housing. At pressures around 60 psi the screen will start to separate from its
support plates, resulting in bypassing of feed material directly into the press liquor
flow.
BUILDING A PLUG
In order for the press to work, a plug of cake must form between the cake
discharge spout and the pressure cone. The press will almost always do this on its
own accord as material is fed into the press.

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In the case of sloppy materials like manure and DAF sludge, it may be advisable to
start off by first packing the discharge of the press with any available fibrous
material.
Alternatively, the press can be turned on and the feed pump allowed to run just
long enough to fill the feed line and the press. Then shut off the pump, leaving the
press running, and wait until no more liquid drains from the screen of the press.
Repeat this process until a plug of cake starts to open the cone.
PRE-THICKENING
Almost always, the thicker a flow going into a press, the better it will work.
If the flow into a screw press is too dilute, the high volume of liquid going through
the press screen can cause either of two problems. The flow may either flush most
of the solids through the screen, or it may plaster solids against the screen, thus
blinding (covering over) the screen.
To prevent these things from occurring, it may be necessary to pre-thicken the flow
ahead of the screw press. This is commonly done with a static screen (sidehill) or
a rotary drum screen (RDS). In the case of very dilute feed to the press, a Vincent
Fiber Filter can be used.
AIR CYLINDER REGULATOR
To regulate the air pressure of the discharge air cylinder, presses are supplied with
an air pressure regulator along with a Parker four-way reversing valve. These
should be installed near the cone end of the press. (Until recently FRL (Filter,
Regulator, Lubricator) sets were provided to regulate air pressure. Most air
cylinder manufacturers now recommend against the use of lubricators.)
The Parker valve allows manual selection of the shut, open, or "neutral" position.
This valve connects air supply from the regulator to one end of the air cylinder,
while simultaneously opening the other end to atmosphere. The vent line on the
4-way valve allows air to escape when pressure is switched from one end of the air
cylinder to the other.
Continuous air flow from the Parker vent line indicates a leak inside the air cylinder,
or possibly a faulty 4-way valve.

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Once material is going through the press, set the 4-way valve so that the discharge
cone goes shut in the "in" or closed position. Start with a low air pressure, working
your way up until the desired performance is obtained.
The neutral position of the Parker valve is used only in testing. If left in the neutral
position, the cone will not move unless it is pushed open by press cake. If, later, the flow
of press cake is diminished, the cone will remain in the position to which it was pushed,
and purging can occur.
FRL AIR REGULATOR WITH 4-WAY REVERSING VALVE
DISCHARGE CONE
The principal adjustment of the press is made with the discharge cone. The cone is the
component at the cake discharge end of the press that acts as a door or stopper plug to
restrict material from leaving the press. The more pressure exerted by the discharge
cone, the drier the cake material will be leaving the press. Also, the motor amps can be
expected to increase with added pressure, and throughput may decrease.
The discharge cone is moved in (actuated) either by an air cylinder or, rarely, by
weights. Typical air cylinder pressures are in the range of 30 to 60 psi. Some
materials will press only in a low range, say 10 to 20 psi. Other materials may
press best with a pressure of 60 to 100 psi. Air consumption is minimal in all
models, 1 to 2 cfm.

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During initial, first-time, start up, presses with air cylinder actuators are generally
started up with the discharge cone in the withdrawn position. This will avoid an
unnecessary jam.
With the air cylinder models, the discharge cone mechanism can readily be
positioned in the "open" (withdrawn or "out") position.
Note that with many materials it is necessary to start the press with the discharge
cone in the closed position at low air pressure. Thin or soupy materials, like
pumped manure or clarifier underflow, can tend to purge right through the press if
the press is operated with the discharge cone open (in the withdrawn ("out")
position).
However, with materials that are dry to begin with, such as sawdust or plastic wash
tank sludge, it becomes more important to start with the discharge cone in the open
position. This is because these materials may tend to jam or overload the press.
Similarly, high freeness materials, from which the water falls away freely, will have
a tendency to jam in a press. Be sure to start the press with the cone open, and
gradually close it with low air pressure, when running such materials for the first
time.
Once you are through the initial start up, it will be unlikely that your press should
have the cone opened before starting. Most operators rarely open or shut the cone
once it is set.
As the pressure on the discharge cone is increased, not only will the cake become
drier, but the flow through the press may also be reduced. With very slippery or
slimy feed material it may be possible to apply enough discharge cone pressure to
stop the flow altogether.
High discharge cone pressures can result in increased quantities of suspended
solids in the press liquor.
Care must be taken if a press is to be left running at a very low pressure like 10 psi. If
some fiber enters between the cone bushing and the screw shaft, it will take more
than that much pressure to close a cone which has been pushed open by a heavy
flow of cake. The result will be either high moisture content in the cake or, worse,
purging.
On models without air cylinders, weights used to actuate the discharge cone vary
considerably. When dewatering food waste there may be a need to minimize the
amount of solids being forced through the screen. At the other end of the scale,

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some KP-10’s used on dairy manure may use a 5' extension arm with a hundred
pounds of weight.
With some feed materials, the press can be operated with the discharge cone in
the withdrawn position. The screw alone may do enough compressing and
dewatering to produce a cake at the discharge.
It is acceptable to open the discharge cone, in most cases, during normal operating
conditions. This allows inspection, while in operation, of the discharge end of the
screw and screen. This will give the operator a chance to observe operation with
minimum dewatering and maximum throughput. It is also a good technique for
purging bad material i.e., either jammed or spoiled material, from the press. (Do
not try this trick if you are pressing hot or chemically aggressive materials.)
Where very low air pressure is required for proper operation, it may be practical to
put the 4-way valve in a neutral position, half way between open and closed. A
press can not be left permanently in this condition: keep in mind that a slug of cake
will push the cone open, and it will not re-close on its own afterwards.
An unusual technique is to set the air pressure so that the cone normally stays
completely shut. A timer is used to periodically open the cone. The closed period
is determined by the amount to time required for press cake to accumulate in the
press. This type of operation is used with slippery or slimy press cake that cannot
be dewatered to sufficient firmness to force the cone open. The duration of the
"cone open" period is long enough to dump the press cake that has been formed.
Cone Timer panels are available from Vincent at no charge.
Once through start-up, the cone is almost always left in the closed position at
whatever air pressure had been found to be effective. A plug of cake will be left
around the cone whenever the press is turned off; this will clear on its own accord
on restarting the press.
There are a few applications where the air cylinder Is removed and replaced with a
jacking bolt. This is used if the cone pushes completely closed even with the
lowest air pressure. It results in operating the press with a fixed discharge annulus.
Air cylinders with linear actuators are available.
ROTATING CONE OPTION
Most KP screw presses are offered with an optional feature which makes the cone
rotate and strip away the press cake. The rotation is driven by two large pins
mounted on the back of the cone. These pins engage with a collar which is clamped

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onto the screw shaft. Press cake is stripped away by studs on the face of the cone.
These studs are in an axial position parallel to the screw shaft.
The rotating cone can serve multiple functions. By stripping the cake away it can
prevent either jamming or purging. Its use generally results in wetter press cake
and lower motor amps. Most commonly it is used when all the press cake tends to
channel out past one side of the cone. It is invaluable in situations where press
cake props open the cone and allows un-pressed material to purge.
The cake will tend to co-rotate with the screw when the cone is rotating. A spin-stop bar,
welded to the inside-bottom of the cake discharge spout, prevents this.
Positioning the drive collar limits the maximum opening of the cone. If a large amount of
cake comes form the press, the cone can run into the drive collar and for it to slip along
the screw shaft.
If the cake comes out too wet, shorten the length of the studs on the face of the cone.
Disconnect the rotating cone by removing the drive pins and/or drive collar.
DRIVE COLLAR AND DRIVE PINS FOR KP STYLE ROTATING CONE
INTERMITTENT OPERATION
In the case of intermittent operation, it is recommended that the control panel for
the feed pump or conveyor which feed the press should have a timer. This timer
should be set to have the press run for two minutes after the feed pump (or
conveyor) shuts off. This will partially clear the press so that it will not trip out on
overload when it is re-started. (This applies in high torque applications or in
installations where the material in the press dries out or freezes.)

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An extreme case occurs when pressing spent coffee grounds and some paper mill
fibers. Each time the press is turned off, the cone must first be opened for a
minute. If this precaution is not taken, nasty damage to the press screw or screen
can occur when the press is re-started.
(See the previous section, INVERTER VFD & PLC CONTROL.)
Minimize the time that the screw press is run with no material being fed into it. The
last material admitted to the press will dry to powder, and it can cause severe
accelerated abrasive wear.
Initially the press will likely be run empty in order to check rotation. Even though some
rubbing may be heard, negligible wear will occur so long that this period is kept to a
minimum. Also, since the screw is supported to some extent by the material inside
the press, running dry may allow the screw to rub the screen.
DOUBLE PRESSING
Some processes benefit from what is called double pressing. This means that the
cake coming from the press is run through the press a second time (or through a
second press). If little moisture is removed in the second (double) pressing, then it
is known that the liquid removed in the first pressing is all of the free liquid that
there is to be pressed out.
Sometimes water is added to the cake in between the first pressing and second
pressing. This is done to enhance the recovery of dissolved sugars in the original
press cake.
Molasses can be added to press cake between the first and second pressing. This
is used to infuse dissolved sugar into the cake, increasing the solids content of the
final press cake.
Capital-effective double pressing can be achieved by using an inexpensive Soft
Squeeze Series KP screw press for the first pressing, following with a tighter-
pressing Series CP/VP in the second position.
MOISTURE CONTENT
A screw press separates free water. This will leave organic water in the press
cake. The organic water is either bound to, or part of, the animal or vegetable
molecules. Mechanical pressure alone will not remove organic water; it takes heat

15
or chemistry. Frictional heat from the press can remove organic water, but this
obviously should be avoided. For chemistry, see the Hydrated Lime, Gypsum and
Alum section. For heat, see the Fluid Injection section.
To determine the moisture content of a material (feed to the press, press cake, or
press liquor), a sample should be weighed and dried overnight at a temperature
slightly less than 100oC. (If sugars are present use less than 70º C to prevent
caramelizing.) The sample should weigh six or more times the tare weight of the
sample tray or cup.
The moisture content of press cake varies considerably. Tomato press cake will be
90% moisture. Orange peel will be 80%, unless it is reacted with hydrated lime, in
which case it will go down to 72% moisture; add molasses and it will go to 65%.
Dairy and hog manure will come out at 70% moisture, unless there is sand or
sawdust in the sample, which will reduce the moisture content. Cellulose fiber from
a paper mill (knots, screen rejects, primary clarifier underflow) will come out about
50%. However, if secondary (biological) sludge is added, then the moisture
content of the cake will go up considerably. With high ash content in paper mill
samples, moisture may go down to 40%. Moisture contents of only 25% can be
achieved pressing things like sand, eggshell, glass, and plastic chips.
The heat from steam injection can change the chemistry of the material being
pressed so that cake with lower moisture content is produced. This blanching or
parboiling effect works with fish and orange peel, for example.
A quick approximation of what to expect from a screw press is to squeeze as much
water out with your fist, and figure that the press will do a little bit better. A better
way is to twist a ball of the material in a cotton cloth.
COMPRESSION
A screw press achieves compression using several methods: (1) The discharge
cone of the press causes back-pressure on the material being dewatered. The
higher the cone pressure, the greater the liquid removal. (2) The pitch of the flights
of the screw tightens as the material is conveyed through the press. This forces
liquid to go through the screen. (3) The diameter of the shaft of the screw may be
increased progressively, forcing material outward, against the screen. This is a
tapered shaft design.

16
SCREW WITH TAPERED SHAFT
Force-feeding (supercharging) the press and applying a vacuum to the outside of
the screen are two additional methods which may achieve compression. These
two are used infrequently because the performance results are uncertain.
PRESS SPEED (RPM)
In general, the slower the screw speed, the greater the dewatering. Longer
residence time in the screened area results from lower screw speed, which allows
time for more thorough dewatering. Unfortunately, it also goes with reduced
throughput capacity.
Screw press speed (rpm) can be changed by using a Variable Frequency Drive (VFD).
Alternatively, the drive motor can be switched to a different pole motor (900, 1200, or
3600 versus the standard 1800 rpm). Most modern motors are good for permanent 120
Hertz operation; they are always good for a test at this high speed.
Higher speed can result in premature gearbox failure. Switching to synthetic oil, replacing
the normal mineral oil, is recommended. Consult the factory for assistance.
A small change in screw speed, like 15%, will generally not result in a measurable change
in performance of the press.
Low screw speeds are used for cooker crumb, potato peel, many sludges, and low
freeness materials in general.
It has become normal for a variable speed drive (frequency inverter VFD) to be
used with Vincent presses.

17
The smaller Nord gearboxes are all rated for 4,000 rpm input, which makes it easy
to switch to a 3000/3600 rpm motor. It is best to switch to synthetic lubricant if this
change is permanent. With other gearboxes, the higher speed can result in
premature gearbox failure. Consult the factory for assistance.
A small change in screw speed, like 20%, will generally not result in a measurable
change in performance of the press.
It has become normal for a variable speed drive (frequency inverter VFD) to be
used with Vincent presses.
Low screw speeds are used for cooker crumb, potato peel, many sludges, and low
freeness materials in general.
CAPACITY MEASUREMENT
The best way to measure capacity of a press is to collect timed samples of press
cake and of press liquor. This should be done during a period of sustained, stable
operation, rather than by timing a batch through the press.
Press cake is generally captured in a tarpaulin, and press liquor in a 5-gallon pail or 55-
gallon drum. When the drain is at floor level, a 3-mil plastic bag can be used to catch
press liquor. If the press liquor goes to a pit or tank, the change in depth can be timed.
Sometimes it is possible to collect only one flow, either press cake or press liquor.
In these cases it is possible to estimate the press throughput if the solids content of
the inbound material and press cake are measured. It is assumed that there are
zero suspended solids in the press liquor, although this is never really the case.
A-B-C-D PLATES
There are four or five vertical plates making up the frame of the press, called out in
the Nomenclature schematic at the end of this manual. Starting from the drive end
of a press with a hollow bore gearbox, the first one is the Adapter Plate. The
gearbox is bolted to the adapter plate. Through four spacers, the adapter plate is
welded to the A Plate. This A Plate forms one wall of the inlet hopper. The shaft
seal housing is bolted to the A Plate.
The next plate is the B Plate. It forms the downstream wall of the inlet hopper. The
screen starts at the B Plate. There is a notch, called a Cord Cutter, in the B plate. Also,
there may be a bar called Brian's Stripper welded to the B Plate, inside the inlet hopper; it
is in a position to kiss the edge of the screw flight as it passes. These two features

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prevent long fiber pieces from balling up at the exit of the inlet hopper. See the section
ahead on Cord Cutters.
The final plate, the C Plate, supports the discharge end of the screen. The cake
discharge spout is bolted to the C Plate. The discharge cone touches the spout
when the cone is in the closed position.
KP-24 and KP-30 presses have a fifth plate, called the D Plate, on which air
cylinders are mounted.
SCREW LIFE
If a press loses its previous throughput capacity, or if cake moisture content
increases, it is can be sign of a worn screw.
A screw can last anywhere from six months to twenty years. It depends on the
material being pressed and how hard it is being pressed.
Premature screw failure can arise from several causes. The two main ones are:
(a) If a press is allowed to run continuously even when no material is being fed into
it, the screw can wear out in one or two months. The same can happen if a very low
flow is consistently fed into the press.
(b) If abrasive material is dewatered with high cone air pressure, rapid wear will
occur. This condition is avoided if a few drops of water can always be squeezed
from a fistful of press cake.
Two effective ways to extend screw life are:
(a) Various grades of hardsurfacing rod can be used to protect the flights of a
screw. The best hardsurfacing will have Tungsten Carbide impregnated in it.
(b) Using a VFD or lower speed motor to reduce the screw rpm will extend screw
life
If a worn screw is suspected, the thing to do is to shut down the press, open the
cone, and dig out the cake until the tips of the last two flights can be seen or felt.
Check how badly the tips are worn. If the there is 3/8” between the tips and the
screen, wear is evident. It is also an indication that the sharp edges of the flights
throughout the press may have worn, becoming rounded. This can cause the
flights to act like a putty knife, plastering solids against the screen, preventing
water from coming through.
Worn screws are either restored locally or returned to Vincent for rebuilding. The
maximum cost of a screw rebuild is around one third the cost of a new screw.

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SCREW CONFIGURATION
Almost all Vincent screw presses use the Interrupted Screw Flight design. The
interruptions leave room for stationary resistor teeth that are mounted outside of
the screen. These teeth go through the screen and reach almost to the shaft of the
screw. This design of screw press stands in contrast to a Continuous Screw
design. The main advantage of the interrupted design is that solids material must
accumulate in the interruptions until sufficient consistency is reached for the solids
to be pushed toward the cake discharge. There is a reduced tendency for the
material being pressed to co-rotate with the screw. Also, there is more agitation
within the press and, consequently, quicker and more thorough dewatering.
The screw starts with a feeder section of continuous flights. This picks up material
in the inlet hopper and pushes it into the screen section. The feeder section ends
at the first resistor tooth. This feeder section of the screw is followed by
compression stages where the flights have reduced pitch. The reduction in pitch of
the flights results in compression of the material going through the press.
A screw configuration referred to as Sterile Butterfly is common. There are a
reduced number of flights on this screw, and the flights do not wrap as far around
the shaft as is normal. This design screw is good for high throughput of materials
which are easily dewatered. Glass and sand are examples.
INTERRUPTED FLIGHTS, RESISTOR BARS, and RESISTOR TEETH.
PIE CUTTING
Sometimes the compression of a screw is reduced, in the field, in an operation
called "pie cutting". This involves cutting pie-shaped segments from certain flights
of the screw, leaving a butterfly (end view) configuration. The modification is done
to avoid excessive compression and jamming. (The "sterile cut" is more drastic.)
Consult the factory for assistance before making this modification.

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4" PIE CUT PIE CUT
NOT PIE CUT BUTTERFLY CUT