Патент USA US2122362код для вставки
June 28, 1938. A_ H, STANTON “ 2,122,362 CONTROL MECHANISM FOR PAPER MAKING MACHINES Filed April 30, 1935 I mue/zfors Patented June 28, 1.938 2,122,362 ‘ UNITED STATES PATENT OFFICE 2,122,362 CONTROL MECHANISM FOR PAPER MAKING ‘ MACHINES ' Avery H. Stanton, Dedham, Mass, assignor to Eldon Macleod, Frank A. Morrison, Cameron Maeleod, Leslie Soule, and Sullivan A. Sargent, Jr., trustees, doing business as Mason-Neilan ' Regulator Company, Boston, Mass. Application April 30, 1935, Serial No. 18,979 7 Claims. (Cl. 34-487) This invention relates to moisture control mechanism for paper making machines, wherein the paper is passed around steam heated drying cylinders, and relates more particularly to appa ratus for automatically controlling the supply of steam to the cylinders, whereby their tempera ture and consequently the moisture content of the paper is regulated. It is, of course, of great im portance in paper making that the moisture con tent of the paper be closely regulated to maintain a small but uniform moisture content as the pa per is delivered from the machine. Heretofore the many variable factors aiiecting moisture con 25 30 _ 35 40 45 50 . the downstream side of the valve. It is also to _ be understood that moisture control may be ef fected in any suitable manner, tension roll con trol merely being one of several suitable methods. 10 Before explaining in detail the present inven tion it is to be understood that the invention is not limited in its application to the details of con struction and arrangement of parts illustrated in the accompanying drawing, since the inven tion is capable of other embodiments and of be weight of the paper sheet, change in density and ing practiced or carried out in various ways. Also freeness of stock, change in air humidity, change it is to be understood that the phraseology or terminology employed herein is for the purpose of in the machine speed, as well as change in tem perature of the drying cylinders due to previous description and not of limitation, and it is not 20 change in pressure or rate of ?ow of the steam intended to limit the invention claimed herein supplied to the cylinders or to change in the rate beyond the requirements of the prior art. In the drawing: of condensate removal from the drying cylinders. Fig. 1 is a diagrammatic view of my control It is also important in moisture control that the control mechanism be instantly responsive to' mechanism in a paper making machine. 25 In the drawing, Ill represents a mechanism for changes in conditions, for if there is time lag in resetting the temperature control point in the maintaining an adequate and constant pressure of air or other suitable ?uid for operating the dryers, the mechanism may be re-setting for con ditions which no longer exist a few minutes later. independent pressure system, and as this device Similarly it is important that the mechanism forms no part of the invention claimed it need 30 not be described in detail. The operating air does not over-control or go too far in ‘each direc tion, as this ‘produces “hunting”.or undesirable pressure is supplied through pipe H and is suit ?uctuation in the range of moisture content. ably ?ltered through the ?lter Hill, the pressure My invention comprises brie?y the utilization gauge l5 indicating the operating pressure. The of two instruments, one a tension roll responsive air passes through pipe II to a pilot valve mech to changes in tension of the paper sheet due to anism 20. The branch pipe I‘! having a restricted moisture content, and the other a temperature ori?ce I8 by-passes the stream of air and ordi bulb responsive to changes in temperature in the narily exhausts it to the atmosphere through ex drying cylinder, which instruments operate the haust ori?ce is at the lower end of branch pipe control valve governing the supply of steam to H. A ?apper lever 55, as actuated by the three 40 the- cylinders through their separate or joint ac responsive instruments to be later described con tion. An independent pressure system, prefer stitutes an adjustable mounting 80 which oper-j ably air and ordinarily exhausting to the atmos ates to close the exhaust ori?ce l9 and thereby phere is used as an operating pressure to actuate build up pressure in branch pipe I‘! below the re the control valve governing the steam supply, and stricted ori?ce l8. 45 operates through a pilot mechanism and exhaust Branch pipe I1 connects with the pilot valve valve, comprising an exhaust ori?ce and ?apper mechanism 20 through the pipe 2| below the re lever. Compensation to prevent over-control or stricted ori?ce l8 which leads into a central dia "hunting” is provided from the operating air phragm chamber 22. A stem 24 abutting the top pressure, which operates to check or compensate side of the diaphragm chamber 22 forms a valve 50 the action of the exhaust valve in one direction between pipe II and chamber 25. A similar stem in response to changes in moisture content or 26 abutting the bottom side of the diaphragm temperature of the cylinders by providing a slight chamber 22 forms an exhaust valve between the movement of the exhaust valve in the opposite chamber 21 and the atmosphere. Both cham direction. It is to be understood that instead bers are connected on the outside by pipe 28 55 trol have prevented the close regulation desired. 15 For instance the factors which may a?ect the moisture content of the paper are .changes in 20 of joint tension roll and temperature control, the joint control may be taken from tension roll and the pressure of the heating medium, or from ten sion roll and from rate of ?ow of the heat ing medium, across any form of ori?ce, both pressure and ?ow connections being taken from 2 2,122,362 ’ which leads through pipe 23 to the controi valve by regulating the amount of steam supplied to 36. A gauge 3| connected to the pipe 29 indi- - the drying cylinders. 'The degree of sheet mois cates the pressure in said pipe, and permits read ing the amount of opening of valve 30, whichiisv calibrated within de?nite pressure limits. Pipe 32 connects the operating pressure in pipe 29 to ' I ‘the Bourdon tube 65 of the adjustable mounting 80 for'providing compensation, as later described. Control valve 30, which is preferably a diaphragm motor valve, controls the admission of steam to the drying cylinders 36, and is shown for purposes I of illustration as normally closed, opening on ap plied air pressure to diaphragm 36a. ‘ The drying cylinders 36 may be one or more, 15 but are here shown as a battery of three with one at the top and two arranged below on either side on asuitable frame 34. Steam is supplied to the drying cylinders 36 through pipe 35, having connections 3511 leading 20 to each cylinder 36. It is understood that the sheet of paper 33 passes around the rotating dry ing cylinders 36, and that any form of heating medium, as hot water, hot air, in addition to steam may be used. Onthe closing of exhaust ori?ce l9, pressure in diaphragm chamber 22 builds up, forcing valve 26 closed and valve 24 open allowing pressure from pipe II to enter directly into chamber 25, ?ow through connecting pipe 28 into chamber 21 30 and equalize the pressures therein. When pres sure in chambers 25 and 21 balances the force in central chamber 22, the valve 24 closes to prevent pressure in chamber 25 from increasing. Air pressure in pipes 28 and 29, in a closed chamber, immediately reacts on diaphragm 30a. to par: tially open control valve 30, permitting more steam to flow into the drying cylinders 36. .t the same time air pressure reacts through pipe 32 on the Bourdon tube segment 85 to provide com 40 pensation, as later described. A thermostat 31 or other temperature respon sive instrument containing an expansible ?uid is provided in one of the drying cylinders 36 pref erably in a dryer subsequent to the tension roll 45 location, and preferably located inside the dryer from the “front" end or in the steam inlet to the dryer. In the drawing, however, for cenvenience of illustration, the connection is shown at the ture content can be varied as desired by chang ing counterweight 65. Movement of tension roll lever 64 compresses or allows to expand a bellows 1| provided in a closed hydraulic pressure system 10 comprising the bellows 1|, tubing 12, a second bellows 13, spring resisted, and connected to a Bourdon tube 14, pictured as a segment rigidly mounted at one end and at its free end connected 10 to an extension 56a. of ?apper lever 56. Bellows 13 is utilized to provide correct de?ection of Bourdon tube 1.4 by absorbing a portion of the pressure created by change in position of bel lows ‘El. ‘ , .15 ' It will be seen, therefore, that my moisture control mechanism controls from the separate or joint action of two instruments, the tension roll 66 being responsive to changes in tension of the paper sheet, and the thermostat 31 responsive to temperature changes in' one of the drying cyl inders 36. These two instruments operate ,» through their separate or joint action to control the supply of steam. to the cylinders through control valve 30, which is set in operation by reg 25 ulating the amount of exhaust to the atmosphere of the independent air pressure system through movement of ?apper lever 56, In case the paper sheet breaks, I have provided a shut-off device for the operating air pressure -30 system comp-rising valve 90. As the paper sheet breaks the tension roll lever 64 drops and oper ates to close the valve 90. This in turn shuts off the air pressure operating control valve 30 and allows it to close, thereby, shutting oh the steam 35 supply to the cylinders. . . The operation of my device is as follows: As the-temperature in the cylinder 36 carrying the thermostat 31 rises, the expansive ?uid in the thermostat 31 increases its pressure and un winds the Bourdon tube 39 which acting through‘ arm 40 lowers ?apper lever 56.partially opening exhaust ori?ce l9. Air pressure in pipe I 1 below the restriction l6 then decreases in diaphragm chamber 22 to release the pressure from chamber 45 21 and pipe 29 through valve 26 from the dia phragm 30a of motor valve 36, to partially close valve 30. This decreases the ?ow of steam through pipe 35 and branch pipes 35a and fur ther increase in temperature in‘cylinders 36 is '50 at one end and at its free end connected to arm prevented. On a decrease in temperature in cyl 40 which in turn transmits motion to ?apper inder 36 carrying the thermostat 31, the action lever 56. The coil 39 may be helical, spiral or isv the opposite. Likewise if the paper sheet be a segment of a Bourdon tube or other device re .comes excessively dry, because of any one of the sponsive to pressure (i. e. pressure responsive variable factors which affect its moisture content, 55 thermostat 31 contains expansible ?lLid). the paper sheet passing between two of the cyl A tension roll device 60, of suitable construe inders will tend to straighten, and this increase tion, as known in the art, is mounted ‘adjacent of the paper sheet tension will cause the tension one of the cylinders 36, to bear yieldingly‘ against roll 60 to yield slightly, thereby elevating lever the travelling sheetef paper. As is well known 64 and‘ compressing bellows 1| in the closed hy the tension roll device may comprise a roller 6|, draulic pressure system 16, and increasing the a bell crank lever 62 pivotally supported at point pressure therein which unwinds Bourdon tube 63 to the frame 34, and a lever 64 also pivotally 14, thereby moving ?apper lever 56 away as to supported at 63 and'movable as a unit with lever partially open orifice l9. Again the independent 62 and having the counterweight 65 attached to air pressure system operates in the same manner 65 one end. By this device the roller 6| is yield as with the increase of temperature of thermo ingly held against the face of the paper sheet 33 stat 31, and allows control valve 30 to partially between’two of the cylinders 36, where the paper close, thereby diminishing the amount of steam is subject to slight sag when its moisture con supplied to the cylinders 36. Likewise on an in steam inlet to the dryer. The thermostat 31 con 50 nects through tubing 38 to coil 39 rigidly ?xed 55 .60 65 ' 70 tent exceeds a predetermined amount and tends to straighten when the moisture content is re duced below that amount. This alternate sag ging and stiffening or straightening of the paper sheet in response to its moisture content is used 75 ’for controlling the moisture content in the paper crease in moisture content in the paper sheet, " decrease in the tension of the paper sheet pro duces an opposite action, to increase the amount of steam supplied to the cylinders. Because there will be a substantial lapse of time before a change in temperature in the cyl 2,122,862 3 inders or the moisture content in the paper can be re?ected through thermostat 31 or tension roll 60 to re-set the motor valve 30, I have pro pendent source of pressure for operating said control valve and ordinarily exhausting to the at mosphere, an exhaust valve governing the exhaust vided compensation through the operating pres from said pilot mechanism, an instrument actu ated by varying tension of the paper, another instrument responsive to a variable character istic of said drying cylinder, joint means operated by the action of said instruments for ac-. tuating said exhaust valve, and means respon sive to the operating pressure afforded by said 10 (Pl sure, which works in an opposite direction to the thermostat 31 or tension roll 60, and whose ac tion is immediately effective on the setting of ?apper lever 56. The setting of ?apper 56 as actuated by changes in temperature of the cyl 1O inders 36 and changes in tension in the paper sheet is immediately compensated or counter acted by the operating pressure without wait ing for the impulse to go through the thermo stat 81 or tension roll 60. For instance as tem perature in cylinder 36 rises and ?apper 56 moves downward through the action of the helical coil 39 to partially open exhaust ori?ce l9 and the operating pressure decreases to partially close control valve 30, the decrease in the operating 20 pressure is immediately re?ected in the Bourdon tube segment 85, which tends to wind and raise ?apper 56, thus partially closing exhaust ori?ce l9. On a decrease in temperature in cylinder 36 the action of Bourdon tube 85 is opposite. 25 Likewise changes in the position of ?apper lever 56 induced by changes in the tension of the paper sheet re?ected through the tension roll 60 are likewise opposed by the action of Bourdon tube 85 acting in opposite direction thereto. It is to be observed that the effect from the 30 operation of the Bourdon tube 85 is to decrease the effect from either tension roll 60 or ther mostat 31 in repositioning the control valve. The effect from tension roll 60 less the effect from Bourdon tube 85 having been positive and causing a reposition of control valve 30 then an opposing action comes from thermostat 31 due to the variation in temperature caused by the reposition of valve 30 and the effect from 31' 40 is to compensate further thus preventing any hunting or overtravel. It further should be ob served that the reactions of thermostat 3‘! occur as fast as the changes within the dryer. The de gree of effectiveness is from 85 and 31 and is 45 proportional to the ratio of fulcrum arms 40, 56 and 56a as set for the particular installation which is adjustable. Thus the compensating ac tion from the operating pressure stabilizes the pilot mechanism'for counteracting movement of said exhaust valve. 2. A moisture control mechanism for paper making machines comprising a drying cylinder, the temperature of which is to be controlled, a source of steam supply for heating said cylinder, a control valve governing supply of steam to said cylinder, a pilot mechanism utilizing an inde~ pendent source of pressure for operating said con trol valve and ordinarily exhausting to the at- ' mosphere, an exhaust valve governing the ex haust from said pilot mechanism, means for di Verting. said pressure to operate said control valve on the closing of said exhaust valve, an instrument actuated by varying tension of the paper, another instrument responsive to the tem perature of said drying cylinder, joint means op erated by the action of said instruments for ac tuating said exhaust valve, and means respon sive to the operating pressure afforded by said pilot mechanism for counteracting movement of said exhaust valve. 3. A moisture control system for paper making machines, comprising a drying cylinder, the tem perature of which is to be controlled, a source of steam supply for heating said cylinder, a control valve governing the supply of steam to said cylin der, a pilot mechanism utilizing an independent source of pressure for operating said control valve and ordinarily exhausting to the atmosphere, an 40 exhaust valve governing the exhaust from said mechanism, a movable ?apper controlling said exhaust valve, a lever supporting said ?apper at one end, a second lever supporting said ?apper at its other end, an instrument responsive to the 45 temperature of the drying cylinder, a coil actu ated by the temperature responsive instrument for moving the ?rst ?apper supporting lever, an control instrument and ‘prevents the usual wide instrument actuated by the varying tension of the paper, a coil actuated by said second instru 50 ?uctuation, thereby rendering this type of con ment for moving said second ?apper supporting trol extremely accurate. By means of my device I am able to, obtain lever, and so actuating said exhaust valve through moisture control of the paper sheet within closer the action of said coils, a third coil responsive to the operating pressure afforded by said pilot limits than before possible with tension roll con mechanism for counteracting the movement of trol and by eliminating “hunting” and over control a uniform steam ?ow ‘to the dryers is said exhaust valve as actuated by the ?rst two obtained, thus providing uniform heat input to coils; 4. A- moisture control mechanism for paper the sheet under uniform conditions of basis of weight and effective drying. This uniform ?ow I making machines comprising a drying cylinder, further aids in boiler plant operation. Because the temperature of which is to be controlled, a 60 of the control from thermostat 31 an anticipatory source of steam supply for heating said cylinder, action is provided wherein changes in steam a control valve governing supply of steam to ' pressure a?ecting the temperature of the dryers said cylinder, a pilot mechanism utilizing an in will re-set the valve before such changes can dependent source of pressure for operating said alter the moisture content of the sheet. Thus a control valve and ordinarily exhausting to the 65 large amount of manual control to meet ‘varying atmosphere, an exhaust valve governing the ex conditions affecting moisture content of the paper haust from said pilot mechanism, said pilot mechanism including a casing, a pair of dia is eliminated. phragms dividing said easing into two outer I claim: 1. A moisture control mechanism for paper chambers and an inner chamber, a supply valve 70 making machines comprising a drying cylinder, and a waste valve in said outer chambers govern the temperature of which is to be controlled, a ing the supply and waste of pressure by which source of steam supply for heating said cylinder, said control valve is operated; the pressure from a control valve governing supply of steam to said said independent source expanding said inner chamber and actuating said supply and waste 75 cylinder, a pilot mechanism utilizing an inde 4 12,122,862 valves to divert said pressure to the control valve pressure afforded by said supply and waste valves for operating the same on the closing of said ‘ex ,t for counteracting movement of said exhaust valve. haust valve, an instrument actuated by varying 6. A moisture control‘ mechanism for paper tension of the paper, another‘instrument respon making machinescomprising a drying cylinder, sive to a variable characteristic of said drying the moisture in the paper sheet vpassing over cylinder, and joint means operated by the action which is to be controlled, a source of heating of said, instruments for actuating said exhaust medium for heating said cylinder, a control valve ' valve. governing supply of heating medium to said cyl- ' 5. A moisture control mechanism for paper inder, a pilot mechanism utilizing an independ 10 making machines comprising a drying cylinder, ent source of pressure for operating said control ‘the temperature of which is to be controlled, a valve, an element responsive to the temperature 10 source of steam supply for heating said cylinder, of said drying cylinder, and joint means operated a control valve governing supply of steam to said by the tension of said sheet and by said tempera cylinder, a pilot mechanism utilizing an inde ture responsive element-for controlling said. pilot pendent source of pressure for operating said to reset the temperature of said cylinder in pro control valve and ordinarily exhausting to the atmosphere, an exhaust valve governing the ex haust from said pilot mechanism, said pilot mech anism including a casing, a pair of diaphragms dividing said casing into-"two outer chambers and an inner chamber, a supply valve and a waste‘ valve in said outer chainbers governing the sup portion to changes in sheet moisture.‘ 15 7. A moisture control mechanism for paper making machines comprising a drying cylinder, the moisture in the paper sheet passing over which is to be controlled, a source of heating me 20 dium for heatingv said cylinder, a control valve ply and waste of pressure by which said control governing supply of heating medium to said cyl valve is operated; the pressure from said inde ‘ inder, a pilot mechanism utilizing an independ pendent source expanding said inner chamber ent sourcelof pressure for operating said control and actuating said supply and waste valves to valve, an element responsive to temperature of 25 said drying cylinder, any element responsive to divert said pressure to the control valve for oper ating the same on the closing of said exhaust valve, an instrument actuated by varying ten sion of the paper, another instrument responsive to a variable characteristic of said drying cylin der, joint means operated by the action of said instruments for actuating said exhaust valve, and - means responsivev to the control valve operating the operating pressure afforded by said pilot for partially o?setting a change in said pressure, and means operated jointly 'by the tension in said sheet, by said temperature responsive element 30 and by said pressure responsive element to reset the temperature in said cylinder substantially in proportion to changes in sheet moisture. AVERY H. STANTON.