US3293770A

US3293770A - Web drying permitting width-wise moisture control

Info

Publication number: US3293770A
Application number: US288335A
Authority: US
Inventors: Fred W Rauskolb
Original assignee: Selas Corp of America
Current assignee: Selas Corp of America
Priority date: 1963-06-17
Filing date: 1963-06-17
Publication date: 1966-12-27
Anticipated expiration: 1983-12-27
Also published as: SE311471B

Description

2 Sheets-Sheet l F. W. RAUSKOLB WEB DRYING PERMITTING WIDTH-WISE MOISTURE CONTROL Filed June 17, 1963 FIG.

Dec. 21, 1966 INVENTOR. FRED w. RAUSKOLB ATTORNEY.

7 Dec. 27, 1966 F. w. RAUSKOLB 3,293,770

WEB DRYING PERMITTING WIDTH-WISE MOISTURE CONTROL Filed June 17, 1963 2 Sheets-Sheet 2 FIG. 3

INVENTOR. FRED w. RAUSKOLB /{@4444 Sham ATTORNEY.

United States Patent 3,293,770 WEB DRYING PERMITTING WIDTH-WISE MOISTURE CONTROL Fred W. Rauskolb, Warminster, Pa., assignor to Selas Zorporation of America, a corporation of Pennsylvania Filed June 17, 1963, Ser. No. 288,335 4 Claims. (Cl. 34-48) The present invention relates to web dryers, and more particularly to a radiant heat dryer that can readily be adjusted to vary its drying eifect as a whole, or to vary its drying effect at various locations across the width of a web.

In drying webs of sheet material, such as paper coming from a paper making machine, for example, it is customary to pass the web over and around a plurality of steam heated drying drums. The heat of these drums drives the moisture from the web. While these drums do a satisfactory drying job, they do have the disadvantage of being fairly slow so that, for a high speed paper making machine, a great number of drums is required. In addition. It is practically impossible to correct wet streaks which appear from time to time across a web. Consequently it is not uncommon for a web to be dryed unevenly from side to side.

It is an object of the invention to provide a radiant heat web dryer. It is a further object of the invention to provide such a dryer that can be built in units or modules which can be adapted for a web of any width.

Another object of the invention is to provide a radiant heat web dryer which can be adjusted to vary the drying effect produced by it along the web or at various individual locations across the web, thereby to compensate for wet streaks in the web so that it will be .dryed evenly from edge to edge.

The apparatus consists of a series of vertically extending heating units that are mounted on opposite sides of the web. These units are mounted on a frame in such a manner that the web can run between them. The units are so controlled that they can be adjusted to vary their heating effect individually or jointly. In addition, the frame can be moved transversely of the dryer for maintenance purposes. The apparatus is primarily intended to be used in connection with an ordinary drum dryer associated with a paper making machine, and will be so described, although it may obviously be used for other drying applications.- The web from -a paper making machine, for example, will move over a series of drying drums for a preliminary drying before going between the drying units. The web will then go over other drums for final drying.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects attained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a side view of the dryer of the invention showing its location with relations to the drums of a conventional paper dryer,

FIG. 2 is a section view of a portion of one of the drying panels taken on line 2-2 of FIG. 1,

FIG. 3 is a diagrammatic view showing the manner in which the dryers are controlled, and

FIG. 4 shows diagrammatically the manner in which fuel is supplied to the various manifolds.

Referring to the drawing, there is shown portions of a frame 1 of a conventional steam drum dryer including 3 ,293,770 Patented Dec. 27, 1966

drums

2, 3 and 4. The dryer of the present invention consists of a pair of panels 5 and 6 that are located between groups of the drying drums. As shown herein the drying panels 5 and 6 are mounted for transverse movement on a pair of

structural steel frames

7 and 8 with the web W being guided from drum 2 over

guide rolls

9 and 10 so that it moves vertically upward between the panels. At the upper ends of the panels the Web passes over a spreader roll 11 and

guide rolls

12 and 13 before going to drum 3.

The drying panels 5 and 6 are identical, so that a description of one will suflice for both and the same reference numbers are used on corresponding parts of both panels. Each panel comprises a rigid steel frame 14, the lower beam 15 of which is hollow for a purpose to be described. The beam 15 rides on rollers 16 which extend transversely of the dryer and are mounted on supports 17 attached to a rigid frame or guide 18. The upper end of each panel is provided with guides 19 that receive between them rollers 20 extending downwardly from a cross piece of frame 7. In this fashion each of the panels is held in a vertical position but can be moved transversely beyond the edge of the web when this is necessary or desirable. The panels can be moved individually or together.

Beam 15 is provided with a horizontally extending shelf 21 that supports the lower ends of a plurality of vertically extending manifolds 22, the upper ends of which are held in position on the frame by means of suitable straps 23. These manifolds are provided with flanges on them to which are attached a plurality of burner units 24, with the burner units spaced vertically and end to end so that they.

form a single vertically extending burner. These burners are similar to those that are disclosed in the application of I. R. Williams et al., Serial No. 283,807, filed May 28, 1962. Each of these elongated burners includes a plurality of burner units, each of which is held in a burner manifold section 25 and each of which is covered by a closely woven screen 26. As explained in said application, the screen is heated to incandescence thereby to project radiant heat against work moving in front thereof.

Each of the manifolds 22 is supplied by a downwardly or upwardly extending pipe 27 that is connected either to a gas supply pipe 28 at the lower edge of the frame or to a similar pipe 29 at the upper edge of the frame, and each of the pipes 27 has in it a pneumatic valve 31 to control the flow of fuel to the burner units supplied by the m-anifold to which it is connected. It is noted that two

supply pipes

28 and 29 are used in order to provide a simpler piping arrangement than would be possible if all of the pipes 27 were connected to a single supply pipe.

Each of the burner units 24 that is supplied by a manifold 22 has a width of about five inches and will dry a strip of the web about six inches wide. Therefore, the various manifolds 22 are mounted side by side, as shown best in FIG. 3 of the drawing, and as many manifolds are used as are necessary for the width of the paper web which is being dried. It is just a question of providing enough of the vertical burner rows to cover the web.

The burner units have a metal frame which could become dangerously hot when there are a number of elongated burners placed close togetheras shown herein. Therefore, in order to prevent possible overheating of the burner units, there is provided a heat sink which may take the form of a pipe 34 of any suitable size, through which cooling Water flows, extending between each of the burner units. These pipes 34 are connected to, and supplied with, water from beam 15, with the water rising vertically through the pipes to discharge into an exhaust pipe 35 that runs the length of frame 14 and which is carried thereby. The hot products of combustion which are pro- 3 duced by the burners rise between the panels and are withdrawn through

sheet metal ducts

32 and 33 that are built into frame 7 on the opposite sides of the web. These products of combustion can be exhausted directly to the atmosphere or they can be used for heating steam which is used in the drying drums.

As noted above, it is intended that the drying panels can be moved transversely of the drying machine. To this end each of

pipes

28, 29 and 35 is provided with flanges that can be fastened to similar flanges of stationary pipes connected thereto. It is noted that water is supplied to beam 15- through an inlet pipe 36 which is also connected to a stationary supply pipe.

When the apparatus is properly located burners of panels and 6 will be directly opposite to each other as shown in FIG. 3, and will be about three inches from the web. The number of burner units 24 in each vertical row of burners will depend upon the drying load the apparatus is to satisfy. Ordinarily the panels will be located between groups of drums at least three quarters of the way toward the dry end of the machine.

In the control of the apparatus, fuel in the form of a combustible mixture of gas and air is supplied through a pipe 37, having a control valve 38 in it, to the

supply pipes

28 and 29. Valves 31 in each of the supply pipes 27 can be individually adjusted, however, and are so connected that the burners facing each other on opposite sides of the web are adjusted together. As shown in FIG. 3, burners across the web are lettered a, b, c and d (only four have been shown in this figure since a greater number would be similarly controlled), and the valves 31 are shown as being of the pneumatic type. Valves 31, controlling the supply of fuel to burners a, are adjusted by air pressure .applied through a tube 39 by a pressure regulator 41 from an air supply 42. In a like manner valves 31 controlling the fuel to burners b, c and d, are adjusted by the pressure of air applied through

tubes

43, 44 and 45 by

pressure regulators

46, 47 and 48, respectively. The pressure applied to main control valve 38 is adjusted either manually or automatically from a control instrument 49 that operates in response to some variable such as temperature or moisture content of the web as measured by conventional responsive elements.

In the operation of the apparatus, the Various valves 31 across the web are adjusted so that the web will be evenly dried. These valves may be adjusted at any time, without disturbing the rest of the machine, to compensate for characteristics of the drums or for dry or wet streaks across the web as the machine is running. Thereafter all of the burners are controlled together in response to the variable being measured by instrument 49 as it adjusts the main fuel valve 38. It is noted that a safety valve 51, which may be a solenoid valve, is placed in the supply pipe 37. The valve is connected with the control circuit for the dryer as a whole, and is closed when the dryer is stopped, thereby to cut off the supply of fuel to the burners at that time.

Ordinarily the web coming into the dryer section of a paper making machine contains about 70% water by weight. This web is moved over the drums of a dryer to reduce gradually its moisture content to from 3 to by weight. With the present invention the first group of drums dries the paper web to about 16 to 18% by weight moisture. At that time the web travels between the panels 5 and 6, which reduce the moisture content to about 6 /2 to 8%. Thereafter the remaining drums dry the paper to the desired final percent moisture. By the use of panels 5 and 6, the speed of drying can be increased about 5% for a dryer of a given number of drums, or the number of drums can be materially decreased for a given speed of drying. Equally important, however, is that the moisture content of the web will be extremely uniform.

From the above description it will be seen that I have provided apparatus that can be adjusted to compensate for moisture variations across the Web as well as lengthwise. Any over-all web moisture changes during a run are counteracted by one over-all throttling control which increases or decreases the total heat output of the dryer in accordance with the changes in the total drying load. This type of control is made feasible by the fact that the heat inertia of the burners is practically nil, as explained in application Serial No. 2183,807.

By threading the web upwardly between the burner panels the possibility of broke fires in the equipment is eliminated. When a break occurs in the web at or ahead of the panels, the trailing end will run through the apparatus. The leading end and any sheet or wads following will not move upwardly between the panels. It is noted that the possibility of a fire is slight because of the rapidity with which the heat of the burners can be reduced. Certainly scorching of the sheet has been no problem. It appears that the energy spectrum of the burners is such that the fibers of the web absorb heat less readily than the water, or, to put it differently, moisture in the web, or water, absorbs the heat readily while the paper itself seems to reflect a considerable part of it.

While in accordance with the provisions of the statutes I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit and scope of the invention set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

What is claimed is i 1. A web dryer panel comprising a frame facing a web to be dried, a plurality of spaced and parallel manifolds attached to said frame, burner units mounted end to end on and supported by each manifold to form in effect a continuous burner on each manifold all of said burner units facing in the same direction toward the web whereby there are parallel rows of burners spaced from each other, the space between rows of burners being open to atmosphere to permit escape of moisture, a main fuel supply pipe, individual supply pipes extending between said main supply pipe and each of said manifolds, valve means in each of said individual supply pipes, a valve in said main fuel supply pipe, remotely located means connected to operate said valve to adjust simultaneously the supply of fuel to all of said burners, and remotely located means connected individually to adjust each of said valve means whereby the burners on each manifold can be regulated separately.

2. The combination of claim 1 in which each of said burners is provided with a closely woven screen facing outwardly, and is also provided with means to heat said screen to incandescence to produce radiant heat.

3. In a dryer for a continuously moving web, the combination of a pair of panels, means to mount a panel on each side of and parallel to a moving web to be dryed, each panel including a frame, a plurality of manifolds mounted on said frame parallel to and spaced from each other and extending in the direction of web movement, a plurality of burner units capable of producing radiant heat mounted end to end directly on and supported by each manifold to form spaced rows of burners, the space between rows of burners being open to atmosphere to permit escape of moisture, the rows of burners on each panel being directly opposite the rows of burners on the opposing panel, means to supply fuel individually to the manifolds of each panel, remotely located means connected to control simultaneously the supply of fuel to manifolds supplying opposed rows of burners on opposite sides of the web, and remotely located means connected to control the supplies of fuel to all of said manifolds on both panels at the same time.

4. The combination of claim 3 in which said means to mount includes means to move said panels beyond the edge of the Web being dryed.

References Cited by the Examiner UNITED STATES PATENTS Montgomery 34-41 Bell 34-4 X Hess.

Kniveton 2663 X Dietrich 263-3 FREDERICK L. MATTESON, IR'., Primary Examiner.

New 34 43 l0 NORMAN YUDKOFF, Examiner.

J. SOFER, A. D. HERRMANN, Assistant Examiners.

Claims

1. A WEB DRYER PANEL COMPRISING A FRAME FACING A WEB TO BE DRIED, A PLURALITY OF SPACED AND PARALLEL MANIFOLDS ATTACHED TO SAID FRAME, BURNER UNITS MOUNTED END TO END ON AND SUPPORTED BY EACH MANIFOLD TO FORM IN EFFECT A CONTINUOUS BURNER ON EACH MANIFOLD ALL OF SAID BURNER UNITS FACING IN THE SAME DIRECTION TOWARD THE WEB WHEREBY THERE ARE PARALLEL ROWS OF BURNERS SPACED FROM EACH OTHER, THE SPACE BETWEEN ROWS OF BURNERS BEING OPEN TO ATMOSPHERE TO PERMIT ESCAPE OF MOISTURE, A MAIN FUEL SUPPLY PIPE, INDIVIDUAL SUPPLY PIPES EXTENDING BETWEEN SAID MAIN SUPPLY PIPE AND EACH OF SAID MANIFOLDS, VALVE MEANS IN EACH OF SAID INDIVIDUAL SUPPLY PIPES, A VALVE IN SAID MAIN FUEL SUPPLY PIPE, REMOTELY LOCATED MEANS CONNECTED TO OPERATE SAID VALVE TO ADJUST SIMULTANEOUSLY THE SUPPLY OF FUEL TO ALL OF SAID BURNERS, AND REMOTELY LOCATED MEANS CONNECTED INDIVIDUALLY TO ADJUST EACH OF SAID VALVE MEANS WHEREBY THE BURNERS ON EACH MANIFOLD CAN BE REGULATED SEPARATELY.