Citrus Installations – Historical (through 2000)

October 25, 2002

Vincent Corporation has specialized in the design and manufacture of citrus feedmill machinery since 1931. We offer unique capabilities to Florida citrus processors because our factory and engineering offices are located in Tampa, Florida. Our dedication to the citrus industry is a company tradition.

Dan Vincent, our founder, started this tradition. His company has been responsible for many innovations over the years. The most basic was covered in a patent issued in 1940, describing the addition of lime to peel in order to make it pressable. This is an indispensable step in citrus feedmills around the world.

In 1970 a patent was issued to Mr. Vincent describing double pressing with the addition of molasses between first and second pressing. All feedmills that double press make use of this technology.

Currently Vincent Corporation has a patent application pending that describes a unique press with twin screws. It describes a screw press that combines a dual screw design featuring interrupted flights. Offering the best performance characteristics of both continuous screw presses and interrupted screw presses, this technology represents a positive advance in the dewatering of citrus waste.

Vincent screw presses built for processing citrus waste are designed to perform under a wide range of conditions. The interrupted screw design assures reliable operation under the full range of normal feedmill situations: start-up without molasses available; under-limed to over-limed peel; pressing cull fruit
along with leaves and branches; thin-skinned early fruit to thick-skinned grapefruit; fresh peel through spoiled peel.

Extra strength is needed to handle over-limed peel. This is because the lime tends to form cement with the peel. Heavy base frames, thick screw flights, heavy duty drives, and burst-proof screens are incorporated into our citrus presses to meet this condition.

The most challenging condition is to process spoiled peel. Even with heavy liming, this peel will dewater poorly. Worse, it tends to blind the screens. Two features of our citrus presses address this situation: (1) The outer edges of the flights are notched over the first half of the press. These notches fill with fiber, which tends to wipe the screen clear. (2) The twin screw design has positive displacement characteristics that force the peel through the press, avoiding co-rotation, even if the screens remain blinded.

Being able to handle tramp metal is another important design feature. Holding an almost constant screw-shaft diameter, until the cake discharge of the press, provides space for tramp metal to pass through the press. This minimizes problems such as jamming the press, folding the flights, or bursting the screens.

In the 1990’s tighter squeezing was designed into citrus presses. This required greater horsepower drives, and vibration became noticeable. Time has demonstrated that this vibration does not result in press failures; nevertheless, it is bothersome. The problem has been resolved in current machines which use direct-coupled drive motors and heavyweight gearboxes.

The 1990’s also saw the advent of pumped peel systems. The wide-range operating characteristic of the interrupted-screw design provided consistent results without modification of the press. For example, two of the presses at the Ft. Pierce feedmill were originally supplied for a conventional feedmill. The transition to pumped peel was made without modifications to the screw presses.

Ease of maintenance is an undisputed advantage of Vincent presses over competitive units. Parts that must be removed, such as screens, are components of a manageable size and weight. Ease of disassembly of the twin screw presses is assured by the horizontal split at the plane determined by the axis of the screws. Brass nuts are used, wherever possible, on stainless steel bolts. Maintenance personnel familiar with more than one screw press manufacturer invariably give Vincent their preference.

Vincent Corporation sustains itself during periods of poor business conditions with a rental fleet of close to one hundred screw presses. Spare parts sales, in contrast, are a minimal part of our business. This is attributable to careful press design, which minimizes wear and damage. Also, the most common maintenance item, patching damaged screens, can be performed by in-house maintenance personnel.

Vincent makes use of standard, off-the-shelf, OEM components. Examples are motors, gearboxes, couplings, seals, bearings and air cylinders. A complete list,
fully describing each component and its manufacturer, is provided with each press. This allows for competitive sourcing of maintenance parts.

The twin screw presses being offered incorporate provisions for the addition of steam. Steam injection will permit dewatering of peel to exceptionally low press cake moisture content. This is not required today. In fact, few feedmills have enough Waste Heat Evaporator capacity to handle the quantity of press liquor that would be generated. However, this technology may become necessary as greater oil recovery is mandated by regulations of the Clean Air Act. When that day comes, you can be assured of having screw presses that are up to the job.

Vincent boasts a long list of satisfied citrus clients. Modern installations in Florida can be seen at Tropicana in Ft. Pierce, Florida’s Natural Growers in Lake Wales, Cargill in Avon Park, and Cutrale in Leesburg. Older installations can be seen at Silver Springs Citrus, Louis Dreyfus in Winter Garden (1954 through 1970), Holly Hill, Parman Kendall, and Cutrale in Auburndale (1956 presses). Our soft squeeze presses are used for first pressing at Louis Dreyfus in Indiantown, Florida’s Natural in Bartow, and Citrus Belle. Outside of the United States, we have presses operating at citrus processing plants in Argentina, Uruguay, Brazil, Costa Rica, Mexico, Jamaica, Australia, Spain, Italy, Greece, and Israel.

Today, most of Vincent’s press business is in the pulp and paper industry. Customers include Kimberly-Clark, Weyerhaeuser, Georgia-Pacific, and International Paper, as well as a great number of lesser-known paper mills. Penetrating this market in the 1990’s lead to numerous design advances that have been incorporated into our citrus screw presses.

Having said this, it remains clear that Vincent, as a Florida corporation, remains dedicated to the citrus industry.

Sincerely yours,
Robert B. Johnston, P.E.