Page 1: Table Of Contents
Vincent In our ninth decade CORPORATION 2810 E. 5 Avenue, Tampa, Florida 33605 Phone: 813-248-2650 Fax: 813-247-7557 E-mail: Vincent@VincentCorp.com August 16, 2014 OPERATING HINTS SERIES KP PRESSES SEE NOMENCLATURE DRAWING AT THE END OF THIS MANUAL INDEX RIGGING INSTALLATION INVERTER VFD & PLC CONTROL...
Page 2 SCREW CONFIGURATION PIE CUTTING JAMMING SCREEN BLINDING CHANNELING PURGING BRIDGING RESISTOR TEETH FLUID INJECTION CORD CUTTER AND STRIPPER POLYMER NOTCHES WIPERS PRESS AID HYDRATED LIME, GYPSUM, AND ALUM PRESS LIQUOR SCREEN SELECTION SCREW-TO-SCREEN CLEARANCE DISCHARGE SPOUT CONE BUSHING WING FEEDERS CLEANING SCREEN REMOVAL SHAFT SEAL...
Page 3: Rigging
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.
Page 4: Inverter Vfd & Plc Control
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.
Page 5: Vacuum Effect
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.
Page 6: Instrumentation
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.
Page 7: Start-Up
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.
Page 8: Building A Plug
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.
Page 9: Pre-Thickening
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.
Page 10: Discharge Cone
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.
Page 11 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"...
Page 12 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.
Page 13: Rotating Cone Option
Press cake is stripped away by studs on the face of the cone. onto the screw shaft. 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.
Page 14: Double Pressing
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.
Page 15: Compression
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 100 C.
Page 16: Press Speed (Rpm)
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.
Page 17: Capacity Measurement
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.
Page 18: Screw Life
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.
Page 19: Screw Configuration
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.
Page 20 4" PIE CUT PIE CUT NOT PIE CUT BUTTERFLY CUT...
Page 21: Jamming
JAMMING Should a press trips out on overload because it has become jammed, a series of steps can be taken to un-jam the press. Generally, the easiest thing to do is to reverse the leads on the electric motor drive. This will cause the screw to feed material backward into the inlet hopper.
Page 22: Screen Blinding
If a press has had extensive use in an abrasive application, the outer diameter of the flights will be worn away at the discharge of the press. Radial wear of 1" to 4" in larger presses will lead to serious jamming and, possibly, a burst screen. When a press is operated in the reverse direction it is possible that solid in the press will be forced against the A Plate.
Page 23: Channeling
runs forward for a given period and then reverses direction briefly for three or four turns when the screen starts to blind. This is one of the easiest possible solutions to test. Sometimes it is the only one that is effective. Many other methods are used to address blinding: (1) Adding notches to the screw, (2) Reducing or eliminating the pressure in the inlet hopper, (3) Adding press aid to the flow, (4) Changing to a different screen selection, (5) Reducing the...
Page 24: Bridging
will strip away the press cake, preventing it from holding the cone open. If the cake comes out too wet, shorten the length of the pins. Purging may occur when there is a much reduced, small flow of cake coming from the press.
Page 25: Fluid Injection
Steam injection works well on pineapple skin, citrus waste, and raw fish. Tests run with steam injection in a Vincent press at Anheuser-Busch showed little benefit. The material being pressed, spent grain, had already been "cooked"...
Page 26: Cord Cutter And Stripper
STEAM INJECTION LAB PRESS IN TWIN SCREW PRESS STEAM INJECTION CORD CUTTER AND STRIPPER Sometimes long stringy material will be pinched where the feeder portion of the screw goes through the hole in the B Plate. This material will co-rotate with the screw and build into a bundle which reduces the flow through the press.
Page 27: Polymer
1/8" deep, 1-1/2" apart) in the outer edge of the screw flights work well. Typically, notching is done from the B plate to the second resistor tooth. Most Vincent presses are supplied with notches. GRINDING NOTCHES IN THE FLIGHTS...
Page 28: Wipers
Lime has been used successfully in the same manner with potato, onion, tomato, and pineapple waste. It works well on acidic materials such as strawberries and coffee bean pulp. Vincent offers lime dosing equipment.
Page 29: Press Liquor
If the press liquor is to be concentrated in an evaporator, better screening than can be achieved with a static screen may be required. Another Vincent machine, the Fiber Filter, provides premium performance. Decanters or centrifuges may be required.
Page 30 Smeared screens can be remedied by running a box cutter blade through the slots. Wedgewire screens in Vincent presses can be reversed in order to achieve double life. That is, wear starts at the cake discharge end of the press. When this occurs,...
Page 31: Screw-To-Screen Clearance
PERFORATED SCREEN WITH REINFORING SHEET PROFILE BAR (WEDGEWIRE) SCREEN SCREW-TO-SCREEN CLEARANCE Generally the clearance between the screw and the screen is 1/32", plus or minus 1/32". The screw should not rub the screen hard, as it can cause wear and premature failure of the screen.
Page 32 the outside of the screen in to the edge of the flight; then subtract the thickness of the wedgewire (generally either 0.250" or 0.375") from the measured depth in order to calculate the clearance. In the case of perforated screen installations, a depth gauge can be used to measure the screw-to-screen clearance.
Page 33: Discharge Spout
DISCHARGE SPOUT The press cake emerges from the end of the screen through a discharge spout. If a press tends to jam, it may be necessary to shorten this spout. Conversely, the spout can be lengthened if the cake does not come out dry enough. There is usually a bar, called a Spin Stop, welded inside this spout.
Page 34: Wing Feeders
Automatic grease systems are available. These should be the high pressure (900 psi) electric or battery variety. Vincent provides these for critical applications, especially pulp & paper. Liquid leaking past the cone bushings drains out the back of the cone (at the air cylinder end of the press).
Page 35: Cleaning
It is unusual that the outside of the screen ever needs to be cleaned. Spray systems for this can be built into the press at the Vincent factory. Alternatively, a pressure washer or swabbing with acid solution can be used.
Page 36 the screen can be turned 180 so that the fresh inlet section is then in the discharge area. In the case of screen failure, frequently a solid patch can be welded onto the screen, from the outside. This is simple as the screen need not be removed from the press.
Page 37: Shaft Seal
SHAFT SEAL The Seal Plate is bolted to the A Plate. This housing may be solid UHMW (ultra high molecular weight polypropylene or polyethylene) or it may contain one or two Johns Manville (JM Clipper) lip shaft seals. There may be a grease fitting on this plate;...
Page 38 If it is tight, the screw is removed using a heavy fine-threaded jacking rod to push the screw out of the gearbox. This rod is threaded through a heavy nut Vincent has provided inside the hollow bore of the larger size gearboxes. This nut has a lug that fits in the keyway, to prevent the nut from turning.
Page 39 MODELS KP-24 and KP-30 Model KP-24 and KP-30 presses use a rigid coupling between the gearbox and the screw. The bolts of these coupling have an extremely high torque requirement. The bars with the resistor teeth must be removed before the screw can be removed.
Page 40: Screw Replacement
SCREW REPLACEMENT When reinstalling a screw, the screw must be pulled in until the step in the shaft seats against the thrust bearing of the gearbox. This will position the flights of the screw so as not to hit the resistor teeth. Be careful when guiding this step in the shaft through the shaft seals.
Page 41: Press Lubrication
This is done with the press in operation. If Vincent does not provide an autolube for a critical operation, we generally tell the operators to manually grease the cone bushings once a shift. We also tell them to...
Page 42: Replacement Parts
The air regulator used with the discharge cone air cylinder may have a lubricant jar. If so, Vincent includes a can of light oil along with the air regulator which comes with our screw presses. The jar should be filled when placing the press in service and when the jar is empty, about once a year.
Page 43 Vincent Corporation has heard of only one injury of this nature with a screw press; do not let yourself become the second. With the smaller KP Presses, special care must be taken when removing the lever arm mechanism that actuates the discharge cone.

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