US2413779A

US2413779A - Apparatus for stripping film from a drying cylinder

Info

Publication number: US2413779A
Application number: US520141A
Authority: US
Inventors: John I Ormond
Original assignee: KRAFT FOODS CO
Current assignee: KRAFT FOODS Co
Priority date: 1944-01-28
Filing date: 1944-01-28
Publication date: 1947-01-07
Anticipated expiration: 1964-01-07

Description

Jan. 7, 1947; J. L-ORMOND 2;413,779

APPARATUS FOR STRIPPING FILM FROM A DRYING CYLINDER Filed Jan. 28,- 1944 Patenterl Jan. 7, 1947 APPAnA'rUs FOR s'mrrrme FILM FR M nDnYmGcYLmnEa John -I. Ormond, Bense nville, 111., assignor to Kraft-Foods Company, a corporation of Delaware Application January as, 1944, Serial No. 520,141

This invention relates to improvements in the art of stripping films from drying cylinders. The

2 Claims. (Cl. 159-11) embodiment of the invention herein disclosed is associated with apparatus employed for-torm-. ing dried films from liquids or solutions. For example, a liquid containing whey and soy flour may be processed into a very thin, dry film, or web, which is subsequently broken into flake after being carried around somewhat more than one-half thecircumference of the cylinder), it is doctored from the cylindrical surface of the cylinder by means of a sharp-edged doctor blade.

of stripped material adjacent the doctor blade while also incidentally removing the creping from the stripped film;-and in general, it is the object of the invention to provide an improved method and apparatus for stripping film from drying cylinders.

Other objects and advantages of the invention will be understood by reference to the following specification and accompanying drawing (1 sheet) wherein" a selected form of the invention is illustrated.

In the drawing, the 'figureis a more or less schematic sectional illustration of rotary cylinder dry Incident to such doctoring operation, the film becomes substantially creped and it has usually been permitted to fall by gravity from the doctor blade into a screw conveyor or other receiver. The film is very thin and fragile and is quite difficult to handle because of the ease'with which it may be broken. It has usually been considered impractical to perform any operations on the film initstravel from the doctor blade to the receiving conveyor or other device. One great difliculty which has been encountered in the handling of film of the character indicated in the conventional method described, has been the tendency of the film doctored fromthe cylinder to fall into surface contact with the dried film remaining on the drying cylinder and approaching the doctor blade. Such contacting of the stripped film with the unstripped film tends to cause the stripped film to be again carried into I engagement with the doctor blade with resultant objectionable accumulation of mate'rialat the doctor blade. Also, it may be observed that ac-' cording to the prior art conventional practices, the tendency for material to accumulate at the doctor blade is somewhat aggravated by the fact that the doctor blade inherently operates to crepe the film as it removes the film from the cylinder. Such creping in itself results in a more or less bunching of material closely adjacent and in contact with the edge of the doctor blade where it operates against the cylindrical surface of the cylinder to .strip film from the latter.

The main objects of the present invention are to prevent engagement of the stripped film with the film-covered surface of the drying cylinder; to effect prompt andsustained removal of the stripped film from the doctor blade; to

provide means for preventing the accumulation ing apparatus having incorporated therein the improved film stripping mechanism.

- The apparatus illustrated comprises a pair of cast iron cylinders 5 and 6 which are suitably journaled for rotation between supporting side plates, one of which is represented at I. The rolls 6 and 6 maybe of cast iron construction substantially 1%" in thickness'and in the neighborhood of 36" in outside diameter. A'pool 8 of the liquid solution or mixture to be formed into a film and dried, is delivered into the bight of the rolls 5 and 6. The rolls are driven in opposite directions relative to each other, as indicated by the arrows 9 and I!) so that their upper adjacent surface portions move toward each other and downwardly. Under such conditions, films II and I! of the liquid will be formed on the surfaces of the cylinders, the thickness or depth of such films being determined largely by the spacing of the cylinders 5 and 6 from each other. Suitable means (not herein shown) are usually provided. for effecting adjustment of one of the cylinders 5 or' 6 toward or from the other cylinder to permit regulation and control of the depth or thickness of the respective films l I and I2.

To retain the liquid pool 8 near the ends of the rolls 5 and 6,- there are provided end plates such as indicated at I3, such end plates having arcuate edges adapted to fit closely against the adjacent surface portions of the cylinders 5 and 6. If desired, a coverplate I4 may extend over the pool 8 of the liquid, such cover plate being supported by the end walls or plates I 3. The films II and I2 of liquid are gradually dried as they approach the opposite'outer sides of the cylinders 5 and 6. In order to dry the film, the cylinders ,5 and 6 are made hollow and provided with suitable connections for 'circulatingsteam or any :other heating medium so as to heat the cylinders.

employed (depending upon the particular prod- 3 uct being dried), and the cylinders have cylindrical walls approximating one and one-quarter inches (1%") in thickness, the outside diameter of the cylinders being thirty-six inches (36") and their length being eighty-four inches (84") For a whey-soy product mixture in the proportions of five and one-half pounds of whey (containing five and five-tenths percent (5.5%) solids)? with two and three-quarters pounds (2%#) of commercially processed soy fiour and approrimately sixty-five/one hundredths pound (.65#) of corn starch, steam at about fifty pounds (50#) per square inch pressure gives good results when the cylinders are rotated at about 6 R. P. 'M. Under such conditions, the dried film will be fairly hygroscopic, containing only about three and one-half per cent- (3 /2%) of moisture.

The dried film is very thin and may be easily broken into fiakes and powdered. However, it is sufilciently self-sustaining to permit it to bedoctored from the respective cylinders on which it is formed without immediately flaking the film.

In the conventional practice, a doctor blade, typified by the doctor blades l5 and I6 respectively, is associated with each cylinder in such a manner as to doctor the film from the surface of the cylinder. The doctor blade is preferably a very sharp-edged blade and most films will be more or less creped incident to the removal thereof fromthe respective cylinders by the doctoring operation.

In order that the film will be adequately dried, it is usually carried upwardly by the cylinder on which formed, to a point substantially above the horizontal plane of the axis of the drying cylinder, the result being that a portion of the surface of the cylinder below the operative edge of the doctor blade extends horizontally outwardly beyond the point at which the doctor blade strips the film from the surface of the cylinder. 7

' upper edge of the chute. This arrangement serves to deliver a creped film to the receiving conveyor,

' at the operative edge of the doctor blade, and between such portions of the doctor blade and the adjacent edge of the chute.

In order to avoid difilculties such as already indicated, and to improve the, form of the product delivered to the receiving means, the trough or chute arrangement, referred to is removed. In order to guide the stripped film away from the cylinder and away from the doctor blade, there are provided rotatably supported rolls, such as rolls l9 and 20. In the arrangement illustrated, the rolls l9 and 20 are rotatably supported by suitable arms or hangers, such as indicated at 2|, which are provided with hooks 22 at their upper ends engaged'overtransverse rods 23 which extend between the opposite side frames of the apparatus. The rolls I 9 and 20 are thus supported in such a manner that by their own weight they maintain surface contact with the adjacent film-covered surface of the respective cylinders a short distance below the operative edges of the respective doctor blades, which'may be carried The film stripped from the,cylinder by each doctor blade is carried outwardly from the doctor blade and'cylinder over the adjacent roll it or 20 and thence permitted to drop downwardly by gravity into the receiving means. The stripped film portions Ha and l2a intermediate the respective rolls l9 and 20 and the cylinders 5 and B will be positively pulled from the doctor blades and cylinders incident to the rotation of the respective rolls. Since the rolls I9 and 20 are driven at substantially the same surface speed as the cylinders, the film portion I la or l2a will be pulled from the respective doctor blades at substantially the same speed that the film on the cylinder approaches the doctor blade. Hence, any creping formed in the films as they are stripped from the cylinders will be substantially pulled out so that the film delivered to the receiving means I! or I8 is a substantially smooth and uncreped film. The uncreped film is advantageous over the creped film in that when flaked or broken, the fiakes or pieces are individually lighter and thinner than the corresponding portions of a creped film. Furthermore, it has been found that the crepe-removing operation has a desirable tendency to lighten the color of the product.

The stripping rolls, such as l9 and 20, should be located at such a point that the contacted film on the cylinder is substantially dry and not subject to being rolled out by the weight of the stripping roll.

Under the operating conditions and for the production of the whey-soy product above mentioned, stripping rolls made of wood and 5" in diameter, spaced about four and one-half inches l from the sharp edge of the doctor blade (to the point of contact between the roll and cylinder) have been found to give good results. These dimensions are not critical and may be varied somewhat. I

The drying and stripping apparatus described may be advantageously employed in producing products based on materials other than whey; for example, buttermilk; skim milk and other milk and non-milk products may also be prepared.

The stripping rolls I 9 and '20 may be driven independently of the drying cylinders and they may be driven at surface speeds which are increased or decreased relative to the surface speed of the cylinders with which they cooperate. If it should be preferred that a slight amount of creping be retained in the stripped film, the stripping rolls may be driven at a surface speed which is slightly slower than the surface speed of the drying cylinder. Similarly, if it is desired 'to effect some stretching of the stripped film (where the character of the film permits it), the stripping rolls may be driven at a surface speed which is slightly more than the surface speed of the drying cylinders. Also, if the characteristics of the film produced permit it, a pressure roll may be associated with each stripping roll so as to more positively grip the stripped film for feeding purposes. However, some limitations on the practicality of more forcibly stripping or pulling the film from the cylinder exist in view of the frailty of the films and the great danger of.breaking the same intermediate the doctor blade and the feed roll. Furthermore, it is not usually desirable that the film be pulled so fast or so hard that it will be removed from the cylinder before it reaches the doctor blade.

Various changes and modifications in the described structure may be made without departing from the invention, as defined in the appended claims.

I claim:

1. In apparatus of the class described, the combination of a rotatably driven drying cylinder, means for forming a film of liquid on said drying cylinder, said film being dried during the rotation of the cylinder, the arrangement being such that the dried film is carried upwardly by the cylinder to'a point above the horizontal plane of the axis of the cylinder, a doctor blade acting on the dried film at said point above said horizontal plane to strip said dried film from said cylinder, and a roll engaging and thereby frictionally driven by the film covered surface of said cylinder below said doctor blade, said roll being adapted to have the film stripped from said cylinder directed over the surface of the roll whereby the roll is operative, as an incident to its rotation, to pull the stripped film from said doctor blade and cylinder, said roll being of such diameter that its face portion remote from said drying cylinder will be spaced horizontally outwardly from the face of said drying cylinder in the horizontal plane of its axis whereby said roll is operative to deliver the film in a vertical plane spaced from the surface of said cylinder.

2. In apparatus of the class described, the combination of a rotatably driven drying cylinder, means for forming a film of liquid on said drying cylinder, said film being dried during the rotation of the cylinder, the arrangement being such that the dried film is carried upwardly by the cylinder to a point above the horizontal plane of the axis of the cylinder, a doctor blade acting on the dried film at said point above said horizontal plane to strip said dried film from said cylinder, and a roll engaging and thereby frictionally driven by the film covered surface of said cylinder below said doctor blade, said roll being adapted to have the film stripped from said cylinder directed over the surface of the roll whereby the roll is operative, as an incident to its rotation, to pull the stripped film from said doctor blade and said cylinder, hangers having said roll rotatably mounted in their lower ends and pivotally supported at their upper ends at an elevation substantially above said roll, said roll being of such diameter that its face portion remote from said drying cylinder will be spaced horizontally outwardly from the face of said drying cylinder in the horizontal plane of its axis, wnereby said roll is operative to deliver the film in a vertical plane spaced from the surface of said cylinder.

JOHN I. ORMON'D.