US1633817A - Method of and apparatus for controlling the moisture content of paper - Google Patents

Description

June 1927' F. E. P. KLAGES METHOD OF AND APPARATUS FOR CONTROLLING THE MOISTURE CONTENT OF PAPER 3 Sheets-Sheet l @OQQQQGQ Q Q O O Q @GQO @GGQ @QGG @000 COCO O G O Q GU09 Filed March 4. 1926 June 1927' F. E. P. KLAGES 1633817 METHOD OF AND APPARATUS FOR CONTROLLING THE MOISTURE CONTENT OF PAPER Filed March 4. 1926 a Sheets-Sheet 2 frwerila' 1,6 1 June 28, 1927. F. E. P. KLAGES 33 8 7 METHOD OF AND APPARATUS FOR CONTROLLING THE MOISTURE CONTENT OF PAPER Filed March 4. 1926 5 Sheets-Sheet 3 Patented June 28, 1927.

UNITED STATES FRANK E. 1.

KLAGES, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE POWERS REGULATOR COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION 01' ILLINOIS.

METHOD AND APPARATUS FOR CONTROLLING THE MOISTURE CONTENT OF PAPER.

Application filed March 4, 1926. Serial No. 92,185.

My invention relates to the art of paper making and particularly to a novel method and apparatus for use in connectlon therewith.

5 While in the specification and appended claims, reference is made to the manufacture of paper, this word is used as a general term,

int-ending thereb to cover not only paper, but board, and ot er pulp products of a similar nature.

In the manufacture of paper, the pulp is delivered to the dryer in a. saturated condition, the moisture being removed pro es- 1 sively by passing the material over a arge number of heated cylinders, until all but a small percentage of moisture has been driven 011'. While it is desirable that a certain amount of moisture be retained in the paper as it leaves the dryers, it is objectionable if too large a percentage of moisture is retained, and thus numerous expedients have been adopted in order to effect some positive regulation of this important element. Apparatus has ,been and is being utilized for this purpose involving the use of hand controlled means for regulating the steam or other heating medium to thealryer cylinders, but as this is to a large extent dependent upon the human element it is uncertain.

An object of my invention is to provide automatic meansada ted to effect accurate and certain control 0 the heat, based on the actual moisture content of the paper sheet at a specified point in its travel toward the end of the dryer. It has been found that by taking the moisture content at the end of the series of dryer cylinders, accurate control cannot be effected for the reason that the paper at that point is so nearly free of moisture that the slight variations that would occur have a nearly negligible effect on a wet bulb thermostat. It has been found also, that by taking the moisture content at a point within the first series of dryer cylinders, regulation is likewise uncertain because even under extreme conditions, the air at such point is fully saturated. I

I have found by experiment that the point in the dryer at which most satisfactory regulation can be eifected by my apparatus is at approximately the beginning of the last series of dryer cylinders. At this point, the

paper still contains a substantial percentage of moisture, as evidenced by the vapor emanating therefrom, and still not such an excess that'efi'ective wet bulb control cannot be had. By withdrawing the air for regulation from the sheet at the described point, I find that accurate regulation is possible without the necessity for previous conditioning of the air. This for the reason that in the vicinity of the dryer there appears to be a substantially constant air condition that is unaffected by existing atmospheric conditions.

My invention contemplates other improvements incident to the effective and economical operation of dryers. For example; I utilize exhaust steam for heating the dryer cylinders and provide means for'supplementing the supply of exhaust steam with live steam when necessary. This is not novel in and ofitself, but I provide novel means for accomplishing the desired result; that is, I arrange suitable control valves in the exhaust and live steam lines, and regulate the position of both of said valves by the wet bulb thermostat that is affected b the air drawn from the paper sheet at the eseribed point. Thus the-apparatus is entirely automatic in character. Other novel features will be described hercafter. a

The invention will be more readily understood by reference to the accompanying drawings, in which:

Fig. 1 is a diagrammatic View of a plurality of series of dryer cylinders, showing the location of the intake for the air used in effecting moisture control;

Fig. 2 is an enlarged view somewhat more in detail, showing the apparatus employed for accomplishing the desired result;

Fig. 3 is an elevation of the box throu h which the airis drawn for effecting the esired control;

Fig. 4 is a sectional view through the regulating instrument, the view being taken on the line 4-4 of Fig. 2; i

Fig. 5 is a side elevation of the air intake P p Fig. 6 is a face view of the'three-way valve and switch, and

Fig. 7 is a sectional view on the line 7-7 of Fig. 6. I

In Fig. 1, I have illustrated diagrammatically a plurality of dryer cylinders, the cylinders belng arranged in series, the first series indicated by the inclusive mark A, the second series by the mark B, and the third series by the mark C. The calendering rolls are indicated at D.

Suitable means are provided for supplying heat in the form of steam to each of the cylinders of the series of dryers, such means not being shown in detail, but being indicated generally by dotted lines in Fig. 2. Exhaust steam is supplied through the main, 10, and a supplementary supply of live steam is provided by the pipe, 11.

Pulp is supplied to the dryer cylinders and passes thereover in the form of a sheet, the moisture being progressively drjaren from the pulp due to the heat in the cylinders.

At a point adjacent to the beginning of the third series, G, of dryer cylinders, I mount an air intake pipe 12, that extends across the width of the sheet and has a narrow opening, 12*, on the side adjacent to the moving sheet. A conduit, 13, conneets the intake pipe with a box 14, shown in detail in Fig. 3, within which is mounted a thermostatic bulb, l5. Wicking, 16 is laid over the bulb, the ends of the wicking projecting into a water container, 17 to which water is supplied by the pipe, 18. An exhaust fan, 19, for drawing air through the box, is operated by a motor, 20, the control switch for which is indicated at 21.

The bulb, 15, is connected by a tube, 22, to a small diaphragm or motor, 23, in the regulator, shown in detail in Fig. 4. Expansion of the diaphragm, 23, due to the development of pressure in the bulb, causes vertical movement of the plunger 24, and the unseating of an air valve 25. Air under 'pressure is supplied through the pipe, 26,

and branch, 27, to the passage, 28, shown in Fig. 4. The opening of the valve, 25,

permits the air under pressure to enter the passage, 29 and to pass through the threeway valve, 30, and pipe, 3],, to the evalve operating motors, 32, 33, controlling the entrance of exhaust and live steam respectively.

The details of the three-way valve are shown in Figs. 6 and 7. Although such details comprise no part of this invention, it may be explained that the valve body contains passages,30 30", 30, in open communication with the pipes, 29, 31 and 42, respectively.

The rotary valve face plate 3O contains two communicating passages, one of which is in constant register with the passage, 30 and theother of which may alternately be placed in register with the passages, 3O or 30% The valve is operated by a lever 30 at one end of which is carried the switch contact piece 21.

.rected to a waste outlet or type; in (other words, the exhaust steam valve is closed by pressure admitted to its motor while the live steam valve is opened under the same pressure.

This arrangement is for the following reason: It will be noted that the exhaust steam main, 10, is provided with the lead 36, to the dryer cylinders, and is continued past the lead, the extension, 37, being diafeed water heater, as desired. A manually controlled valve, 38, in the line, is normally closed. and the supply of exhaust steam to the dryer is regulated by the valve,,'34-, in a by-pass line, 39, around the valve, 38. Thus the supply of steam to the cylinders is discontinued by the opening of the valve, 34.-

It is explained at this point that the springs, 40, resisting the action of the motor, 32, are weaker than the similar springs, 41, controlling the action ,of the motor 33, so that the operation of the valves, 34, and 35, is sequential and not in unison.

As a means for maintaining a fixed reduced supply of heat to the cylinders, during the periods when the dryer is temporarily stopped, asby the breaking of a sheet, I provide the three-way valve, 30 associated with the switch, 21, and connect a pipe, 42, to the valve, and to the air line, 26. In the pipe, 42, I provide a reducing valve, 43, so that the pressure available .inthe pipe, 42, is materially less than that normally utilized. On the interruption of the dryer operation, the, threeway valve is manually moved, thus operating the switch, 21, stopping the motor, 20 and connecting the pipe, 31 with the pipe, 42, so that a reduced air pressure is constantly exerted on the motors, 32, 33. Thus a small. amount of heat is constantly supplied to the dryer cylinders due to the supply of sufiicient power to the motor 32 to partially close the valve, 34, thus permitting some exhaust steam to enter the lead, 36, the remainder passing through the outlet, 37.

The operation is as follows: Assuming normal rotation of the cylinders, and travel of a sheet indicated by the letter E. and the operation of the motor, 20, and exhaust fan, 19, a bodyof air is constantly drawn over the sheet from the point where it leaves the second series B of the dryer cylinders. This body of air will carry moisture according to the quantity being driven from the sheet at the point where the air is taken over the sheet. This body of air enters the box 14, and contacts with the wick, and the wet bulb is influenced in the well known manner. Assumin a lack of moisture according to the preetermined standard, the

opening movement of the live livering a body of wick will give oif to'the air an increased quantity of water, thus reducing the temperature within the bulb and reducing the pressure within the regulating diaphragm, 23., thus closing or partly closing the air valve, 25. This consequently reduces the pressure within the motors, 32 and 33 and permits'an opening movement of the valve, 34 under the action of the springs, 40. There will be no efi'ect on the valve, 35. The increased opening of the valve, 34 permits a greater quantity of exhaust steam to escapeand reduces the quantity being supplied to the pipe, 36.

Assuming a reverse condition, that is, where the paper at the described point contains an excess of moisture, the reverse condition will take place and a greater pressure will be exerted on the motors, 32, 33, thus closing the valve, 34, and tending to open the valve, 35. If the supply of exhaust steam is insufiicient to furnish the amount of heat required, a still greater pressure exerted through the elements described will cause an steam valve, 35, and the supply of exhaust steam will be augmented.

As previously described, it the operation of the dryer is interrupted, the three-way valve and switch are manually operated, thus throwing the automatic regulation out of operation and serving to maintain a fixed reduced supply of steam at all times to the cylinders.

lVhile I have illustrated an air intake of very simple form, consisting merely of a pipe having a slit in one side so that the air is caused to travel over a limited area of the moving sheetfthis detail may be modified considerably with equally advantageous results. Other details of the apparatus may bechanged, including the location described of the intake point for the air. While the general location described is considered essential, it is not the exact point indicated. These and other modifications I consider within the spirit of my invention.

I claim:

1. The method of regulating the moisture content of a sheet of paper during the process of manufacture, which crmsist-s in drying said sheet by a continuous process, do air over and in intimate contact with the moving sheet at a point a substantial distance short of the point of completion of said drying process, then continuousl testing the moisture content of said l)0( y of air, then controlling the heat supplied to said sheet of paper during the process of drying in accordance with the moisture content of said body of air.

2. The method of regulating the moisture content of a sheet of paper during the process of manufacture, which consists in dryimperative that it be at cylinders,

ing said sheet by a continuousdrying step, then continuously testing the moisture content of said sheet at a point substantially short of the point of completion of the dry mg ste then controlling the heat supplied for sait drying operation in accordance with the moisture content of said body of air.

3. The method of controlling the amount of moisture in a sheet of paper during the process of manufacture, which consists in drying said sheet by a continuous )rocess, then continuously testing the wet bu b temperature of said sheet at a point a substantial distance short of the point of completion of said, drying process, then regulating the heat supplied during said drying process in accordance with the wet bulb temperature.

4. Apparatus of the character described,

comprising in combination a plurality of series of dryer cylinders, a fan, means associated with said fan for drawing a body of air over the surface of a sheet of paper passing over said cylinders at a point adjacent to the beginning of the last series of dryer cylinders, means for supplying heat to said cylinders, a wet bulb thermostat for controlling the supply of heat, the wet bulb of said thermostat being positioned to be acted upon by said body of air. I

5. Apparatus of the character described, comprising in combination a plurality of series of dryer cylinders, means for supplying heat to said cylinders, a thermostatically "controlled valve for regulating the supply of heat, a wet bulb thermostat, an air conduit and intake, said intake beinglocated closely adjacent to the surface of the moving sheet of paper at a point adjacent to the beginning of the last series of cylinders, and a fan for drawing air through said conduit, and causing the air to act on said Wet bulb.

6. Apparatus for heating and. controlling the heat of paper dryers, comprising the combination of a plurality of series of dryer means for supplying exhaust steam to said cylinders, ing the supply of exhaust steam with live steam, valves for controlling the entrance of said exhaust and live steam, a single wet bulb thermostat for actuating both the said valves in proper sequence, means providing a conduit and air inlet and a blower, said air inlet being located adjacent to the surface of a sheet of paper on said cylinders, said wet bulb thermostat being located in the path of travel of the body of air induced by said fan through said conduit.

7. Means for effecting travel of a sheet of paper under treatment, means for con tinuously testing the wet bulb temperature of said paper at a point in its travel, and means controlled solely by said wet bulb temperature for regulating the moisture content of said paper at the point where said test is taken.

and for supplement- 8. Means for effecting travel of a body of thereby controlling the moisture remaining material under treatment, means for continin the material at the point Where said test uously testing the moisture content of the is taken. material by a wet bulb thermostat, and In testimony whereof I have aflixed my means controlled solely by said wet bulb signature.

lhermostat for regulating the heat supplied I to said material throughout its travel and FRANK E. P. KLAGES.

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