US2867220A - Humidification chamber - Google Patents

Description

Jan. 6, 1959 H. CAHN ETAL 2,867,220

' HUMIDIFICATION CHAMBER Filed Sept. 5, 1956 INVEN TOR. HAROLD CAHN By WILLIAM J. THEROS AGENT United States Patent HUMIDIFICATION CHAMBER Harold Cahn and William J. Theros, Lancaster, Pa., as-

signors to General Cigar Co., Inc., New York, N. Y., a corporation of New York Application September 5, 1956, Serial No. 608,149

5 Claims. (Cl. 131-136) This invention relates to a humidification chamber used in conjunction with a conveyer belt.

There are several instances in which a layer of material disposed on an endless conveyer belt is treated with a liquid spray or mist. An illustration of such an operation is found in U. S. Patent 2,747,583, granted May 29, 1956, to W. G. Frankenburg and A. M. Gottscho, showing the production of a tobacco sheet by spreading a thin layer of an aqueous paste containing pulverized tobacco and a binding agent on the surface of an endless conveyer belt and by passing the layer of tobacco paste on the conveyer belt through drying chambers wherein the water is evaporated and the paste is converted into a continuous tobacco sheet. As shown in the Frankenburg and Gottscho patent, the tobacco sheet thus formed is then moistened or humidified by a fine water mist deposited on the tobacco sheet by a spray or fogging nozzle. In this illustrative instance as well as in other instances wherein a material deposited on a conveyer belt is to be sprayed, it is important that the spraying be carried out uniformly and without large liquid drops falling on any portion of the material that is being sprayed.

Where the moistening operation is carried out, as shown in the Frankenburg and Gottscho patent, without enclosing the area in which the fine mist is applied to the material on the conveyer belt, a large portion of the water mist is blown by air drafts away from the material to be moistened with the result that the material is not uniformly treated and the room in which the operation is conducted, in any event, becomes unduly humid to the discomfort of the operating personnel and to the detriment of the equipment because corrosion is promoted by a humid atmosphere. Chambers to confine the fine water mist to the desired work area on the conveyer belt have been proposed but none found satisfactory from the points of view of simplicity, cost and performance.

Accordingly, a principal object of this invention is to provide a humidification or spray chamber for use with a conveyer belt which is of very simple construction and low cost and which in operation is trouble-free.

Other objects and advantages of this invention will be apparent from the description which follows and which will be facilitated by reference to the accompanying drawing of which:

Figure 1 is a sectional elevation of an illustrative humidification chamber, the section being taken transversely with respect to the length of the conveyer belt over which the chamber is disposed; and

Figure 2 is a sectional elevation of the same illustrative chamber, taken along the line 22 of Figure l.

The humidification or fogging chamber comprises four sides. Side walls 11 and 12 disposed along the opposite edges of conveyer belt 13 are slightly inclined with respect to the vertical direction so that the upper edges of sides 11 and 12 are further apart than their lower edges. End walls 14 and 15 are joined to sides 11 and 12 to form the fogging chamber 10. A spray or fogging nozzle 16 is attached to end wall 14 approximately over the cen- 2,867,220 Patented Jan. 6, 1959 a CC ter line of conveyer belt 13. Like sides 11 and 12, end

wall 15 is inclined at least a few degrees with respect to the vertical direction so that the inner surface of wall 15 is inclined inwardly when viewed from its upper edge.

The liquid spray issuing from nozzle 16, while directed toward the surface of conveyer belt 13, will inevitably also moisten the walls of chamber 10, particularly sides 11 and 12 and end 15. The liquid collecting on these walls will drain toward the bottom deges thereof without any liquid drops falling from these walls onto the conveyer belt 13 because of the slight inward inclination of the inner surfaces of these walls. Drops of liquid falling from any part of chamber 10 onto the material disposed on the conveyer belt are very undesirable because such liquid drops will stain or otherwise damage the material.

End wall 14 is not exposed to the impingement of the liquid spray as are the other three walls of chamber 10 because nozzle 16 is aimed in a direction away from wall 14. Consequently, the inclination, if any, of end 14 is relatively unimportant and, as shown in Figure 2, may even have its inner surface inclined in a direction opposite to that of the other three walls.

Liquid draining down the inner surfaces of the walls of chamber 10 is collected in troughs 17 and 18 disposed along the bottom edges of sides 11 and 12, respectively, while troughs 19 and 20 are similarly positioned along the lower edges of ends 14 and 15, respectively. End troughs 19 and 20 are positioned above the surface of conveyer belt 13 as well as above side troughs 17 and 18. As shown in Figure 2, end trough 20 extends over the full'width of conveyer belt 13 and the opposite ends of trough 20 are open so that liquid may drain therefrom into the lower side troughs 17 and 18 disposed on the opposite sides of conveyer belt 13. While little or no liquid will ordinarily accumulate on the inner surface of end wall 14, trough 19 is attached thereto as a precaution and its construction is substantially identical with that of trough 20 so that liquid may drain from the opposite ends of trough 19 into the lower side troughs 17 and 18. Each of troughs 17 and 18 is provided with one or more drain taps 21. In Figure 2, trough 17 is shown provided with drain taps 21 at approximately the opposite ends thereof. While the ends of troughs 19 and 20 are open so that liquid may run out at these points, the ends of side troughs 17 and 18 are closed and the liquid accumulating in these troughs is drained entirely through drain taps 21.

An important feature of the humidification chamber 10 is the controlled, aeration or ventilation thereof. For

this purpose, the upper portion of chamber 10 is provided with at least one port 22 in the vicinity of the end of the chamber opposite that holding spray nozzle 16. In the embodiment shown in-the drawing, chamber 10 is provided with two ports 22 in the opposite sides 11 and 12. Ports 22 are then connected by suitable ducts (not shown) to a suction fan or blower which will exhaust air and entrained mist from chamber 10 to any desired point, usually outside the building in which conveyer belt 13 is installed. The top or ceiling 23 of chamber 10 is positioned so as to help achieve the controlled ventilation of this chamber.

For this purpose, the edges of ceiling 23 are slightly spaced from the upper edges of walls 11, 12, 14 and 15. Brackets 24 support ceiling 23 in this spaced relationship to the walls of chamber 10. By maintaining a narrow slit or longitudinal space along the edges of ceiling 23, the exhaust fan drawing air from ports 22 induces a flow of air to enter chamber 10 substantially along the inner surface of ceiling 23. The layer of air flowing rapidly along the inner surface of ceiling 23 prevents stray mist particles from impinging on the inner surface of ceiling 23. In the absence of this protective air shield, stray 3 mist particles impinge on the inner surface of ceiling 23 to the extent that liquid accumulates thereon and "droplets then fall ofi onto the material disposed on conveyer belt 13. As previouslystated,such droplets are highly undesirable since they are damaging'fio the material carried on conveyer belt13'.v 7

The controlled ventilation of chamber 10 so as to avoid the collection of mist on the bottom of ceiling 23 and the resulting dropping of liquid therefrom may be readily achieved by the quantity of air drawn through ports 22"by the exhaust blower and/or by adjusting the spacing between ceiling 23 and the upper edges of walls .11, 12', 14 and 15. For this purpose, brackets 24.may be made adjustable so as to varythe spacing along the edges of ceiling 23. The number and position ofjexhaust ports 22 may also be varied to provide the desired flow of; air'along the bottom of ceiling 23 and'thus prevent the accumulation of liquid thereon.

;In:the humidification chamber shown in the drawing, side 11 is provided with adoor 25, which may conveniently be plate glass or a clear plastic sheet, so that it may be opened to make adjustments of the spray nozzle 16 and may be used to observe the operation; A light fixture 26 is attached to end to illuminate chamber 10'and facilitate observation of the operation through the glass or plastic door 25.

In effect, conveyer belt 13 is the floor of fogging chamber 16. When in operation, belt 13 moves over a plurality of idler rolls 27 spaced'along and supported by base frame 23 of the conveyor structure. End walls 14 and 15 of chamber 10 are cut away along their lower edges so as to clear belt 13 and the layer of material deposited thereon. Belt 13 may be made to move either concurrent or countercurrent with respect to the general direction of the liquid spray from nozzle 16.

As a specific example of the invention, for a stainless steel belt 46 inches wide used in producing a tobacco sheet as described in the aforesaid Frankenburg and Gottscho patent, the humidification chamber is approximately 12 feet long and 4 feet high. The end walls of the humidification chamber are about 53 incheswide along their lower edges where they straddle the steel belt and are about 65 inches wide along their upper edges. The ceiling is fastened to the walls of the humidification chamber to provide a half inch vent along its four edges. An exhaust port 10 inches in diameter is cut out of each of the two side walls of the chamber near the end wall opposite the spray nozzle; The exhaust ports which are opposite one another have their uppermost edges approximately 6 inches below the upper edges of the side walls. Ducts connected to the two exhaust ports extend to a manifold connected to the suction side of an exhaust blower. The fogging nozzle is fastened to the end wall remote from the exhaust ports at a point in this end wall which isabout 15 inches above the center lineof the conveyer belt.

Various modifications of the invention will be obvious to those skilled in the art and, accordingly, such modifications conforming to the spirit of the invention are to be considered within the scope of the appended claims.

What is claimed is:

1. The combination of a conveyer belt and a humidification chamber disposed over said belt, which comprises two side walls positioned along the opposite edges of said belt, two end walls extending transversely with respect to the length of said belt, a ceiling held with its edges in spaced relation-to the upper edges of said side walls and said end walls, means for humidifying the space over said belt and within said chamber formed by said side walls, said end walls and said ceiling, and means for exhausting the atmosphere from within said chamber at a level in the upper portion ofsaid. chamber-but below the upper edges of said side walls and said end walls. V

2. The combination of claim 1 wherein said side walls are disposed with theirupper edges; further apart-than their lower edges, and each ofsaidsidewalls and said end walls is provided with a trough near its lower edge to intercept the flow of liquid draining down its inner surface.

3. The combination of a conveyer belt and a humidification chamber disposed over saidbelt, which comprises two sidewallspositioned along the opposite edges of said belt, two end walls disposedcrosswise to said belt and joined to said sidewalls, a ceiling held with its edges in spaced relationto the upper edges of said side walls and said'end'walls, a spray nozzle disposed'above saidbelt near one of said end walls and directed to spray into said chamber formed by said side walls, said end walls and said ceiling, and exhaust ports disposed near the other of said end Walls in the upper portions of said side Walls but spaced from the upper edges of said side walls.

4. The. combination of claim 3 wherein each of said end walls .is provided with an open-ended trough near its lower edge to divert liquid draining down its inner surface away from the surface of said belt, and each of said side walls is provided with a trough near its .loweredge but disposed below said open-ended troughs to catch the flow of liquid therefrom.

5'. In a spray chamber having four walls and a'ceiling,

, the improvement of means for preventing the impingement of spray droplets on said ceiling which comprises narrow vents disposed contiguous to theedges of said ceiling, and air exhausting means arrangedto draw air.

from within said chamber at a level below said vents.

References Cited in the file ot-this -patent- UNITED STATES- PATENTS 844,583 Dixon Feb. 19; 1907 2,104,036 Harris Jan. 4, 1938- 2,767,717 Schlossmacher Oct. 23, 1956 FOREIGN. PATENTS I 461,532 Canada Dec. 6, 1949

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