Plastic article or earthenware shaping or treating: apparatus – Preform reshaping or resizing means: or vulcanizing means... – Surface deformation means only
Reexamination Certificate
1999-03-03
2001-07-10
Mackey, James P. (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Preform reshaping or resizing means: or vulcanizing means...
Surface deformation means only
C425S403100, C425S404000, C425S445000
Reexamination Certificate
active
06257865
ABSTRACT:
This invention relates to the formation of texturized molded concrete products and, more particularly, to texturizing stations operating in conjunction with product molding machinery to force spray the upper surfaces of “green” molded concrete patio slabs, paving stones, retaining wall units, blocks, and the like being transported on molding machine pallets. The system, which is described in provisional application, Ser. No. 011,016, filed Feb. 1, 1996, from which priority is claimed, is incorporated with a molding machine to operate continuously in correlation with the speed that products are continuously molded and released on their molding and transport pallets.
BACKGROUND OF THE INVENTION
One of the salient features of the present system, which operates with horizontal discharge molding machines, such as shown in the present assignee's U.S. Pat. Nos. 4,260,352 and 4,235,580, both of which I incorporate completely herein by reference, is the treatment of the upper surfaces of the stones or products from above while the products move continuously in horizontal disposition on the molding machine discharge conveyor or an extension thereof. The texturizing which occurs is performed on the so-called “green” products before any curing takes place.
SUMMARY OF THE INVENTION
The method to be claimed involves treatment of the pallet-supported products moving on the molding machine conveyor in a continuous manner correlated with the speed of the molding machine. The conveyor transports the pallets through a texturizing system which includes the steps of providing high intensity liquid spray tubes or bars carrying a series of relatively closely spaced spray nozzles extending in a line broadside to the path of travel. The pair of water spray bars shown in the drawings are spaced apart such that the spacing between them is approximately equal to the length or diameter of the product proceeding past them. Downstream from them, and spaced from them about the same distance, is a so-called air knife which blows air under considerable pressure down upon the products and the cementitious particles which have been separated from the concrete matrices by the high pressure water spray nozzles. The air knife blows the water and these particles from the upper surfaces of the continuously moving products as they proceed on their molding pallets in the direction of pallet flow. Provided further downstream from the air knife, is a surface flooding water spray bar which sprays at a considerably reduced pressure and tends to entrain any final cementitious fines not previously removed.
Finally, the palleted products are encountered by a pair of final air knives which blow the liquid, with its entrained fines, off the surface of the pallets so that the pallets exit from the terminal air knives in a clean and texturized state. The products proceed on to a curing kiln, or to a curing shed where they are cured.
A typical textured surface is one which is attractively rough and has particles of aggregate exposed in the underlying concrete matrix to provide a highly desirable appearance. Alternatively, the spray can be controlled to simply rough the surface without exposing the particles of aggregate. The initial spraying, which is accomplished at a controlled high pressure, must be only of a duration to accomplish the purpose without unduly wetting the product so that it tends to sag out of shape. Typically, what is washed away is portland cement particles which may be referred to as the excess portland cement and smaller pebbles (i.e. fines), and what remains are relatively larger stones (i.e. aggregate) of a selected size, shape, and color bound together by a suitable concrete binder, to leave what may be termed an attractive texturized surface. The primary water spray intensity is such as to, if desired, exposed aggregate as deep as 0.375 inches.
One of the prime objects of the invention is to provide a system of the character described which can either be retrofitted to existing equipment, or placed on new equipment and incorporated into the molding machine control panel.
Another object of the invention is to provide a system in which each pallet remains horizontal and in motion, with no need for stopping or inclining the pallet, which steps require additional time.
Still another object of the invention is to provide a system of versatile character which permits controlled variance of both the quantity and pressure of the water sprayed on the top surface of the products being texturized.
Still another object of the invention is to provide a system with air knives capable of using amplified plant compressor air to produce high flow, high velocity curtains of air to blow off water and debris from the products and pallets, before the water has an opportunity to soak into the products, and to do this in a manner which creates considerable processing savings and reduces processing noise levels.
Still another object of the invention is to provide a system wherein a final cleaning of the product with fresh water is utilized, prior to the step of blowing the water off the pallets and products.
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Besser Company
Heckenberg Donald
Mackey James P.
Reising Ethington, Barnes, Kisselle, Learman & McCulloch, P.C.
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