US2598852A

US2598852A - Feed regulator for paper machinery

Info

Publication number: US2598852A
Application number: US685796A
Authority: US
Inventors: Stephen A Staege
Original assignee: Black Clawson Co
Current assignee: Black Clawson Co
Priority date: 1946-07-24
Filing date: 1946-07-24
Publication date: 1952-06-03
Anticipated expiration: 1969-06-03

Description

June 3, 1952 s. A. ISTAEGE 2,598,852

FEED REGULATOR FOR PAPER MACHINERY Filed July 24, 1946 Control I 40 Mechanlsm I"=l Mechamsm 60 a 5256 1 E 62 F 50 57 Control 'Mechamsm 6 5/ 3 953 7 9 -20 Q II: 4'5' 5 44 x F/ V I I 46 E E INVENTOR. W4. 51b 48 4 BY ATTORNEYS Patented June 3, 1952 REGULATOR FOR PAPER MACHINERY Stephen A. Staege, Hamilton, Ohio, assignor to The Black-Clawson Company, Hamilton, Ohio,

a corporation of Ohio Application July 24, 1946, Serial No. 685,796

3 Claims. 1

This invention relates to paper manufacture and more particularly to a stock supply for a paper machine.

One of the principal objects of the invention is to provide a stock supply system for a paper machine which is simple and reliable in construction and accurate and precise in operation for maintaining proper pressure on the stock as delivered to the slice adjacent the forming member within accurate limits and substantially free of objectionable overtravel, hunting or other fluctuations.

Another object is to provide a control system for the supply of stock to a forming member wherein the white water draining from the forming member is recirculated and new stock added thereto and wherein the pressure on the stock at the slice adjacent the forming member is accurately controlled to correlate its spouting velocitywith the speed of the formin member.

Still another object is to provide such a control system which includes a pump positioned to supply stock from the screen to the forming member and having its output regulated by controls responsive to changes in the supply of stock from the screen to maintain uniform pressure on the stock at its point of delivery to the forming member.

It is also an object of the invention to provide a control system for the supply of stock to a forming member which includes a pump for supplying stock to the screen and another'pump positioned between the screen and the forming member and having its output regulated in response to changes in the level of stock in the screen collecting chamber to maintain this stock level substantially uniform.

A further object is to provide a recirculating stock supply system wherein variation in the supply of stock to the screen is compensated for at the forming member by adjustment of the output of a pump positioned between the screen and forming member.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawing and the appended claims.

In the drawing- Fig. 1 is a diagrammatic view of a stock supply system in accordance with the invention; and

Fig. 2 is a fragmentary view partly in side elevation and partly in vertical section illustrating. control apparatus utilized in the system shown in Fig. l. 1 v

The drawing shows a preferred embodiment of the invention as applied to a paper machine of the Fourdrinier type in which the forming wire In travels over a breast roll II. The white water draining from the forming wire is collected in the wire pit or other collecting trough I2 and together with new stock supplied through pipe l3 from a suitable regulator box, flows through pipe M to a pump I5 such as a centrifugal pump, the supply of new stock being shown as controlled by a suitable valve IS in pipe I3.

The resulting stock mixture is supplied through a pipe ll, shown as provided with a suitable control valve [8, to a suitable screen I9 and thence to a screen collecting box or chamber 20 forming a header.

The screened stock from this header 20 is supplied by means of a second pump 22 and conduit 23 to a suitable stock inlet 25, which is shown as a counterflow inlet of the construction disclosed and claimed in Patent No. 2,347,717, assigned to the same assignee as this application. This inlet 25 includes a pair of oppositely arranged tapered passages 26 and 21 separated by a common wall or baflle 28 and provided with a common discharge orifice or slot 29. From this orifice 29, the stock flows through a tapered inlet passage 30 to the slice 33, the upper slice lip 34 being illustrated as adjustably mounted and provided with suitable control means 35 for regulating its position to control the size of the slice opening.

In the operating of a paper machine of the type shown in Fig. 1, preferred results from the standpoint of uniformity in the finished paper are obtained when the spouting velocity of the stock, i. e., its velocity at the point of delivery to the forming member through slice 33, substantially coincides with the speed of the forming member itself. It will also be understood that it is frequently desired to change the speed of the forming member over a substantial range where changes are made in the weight or other characteristics of the sheet, or in the furnish or other factors. In order to obtain the proper spouting velocity, there must [be proper correlation between the pressure on the stock immediately adjacent the slice and the speed of the wire or other forming member. Also, "since the consistency or quantity of fiber in the stock is relatively low, of the order of 1% or even less, it is important from the standpoint of uniform results that changes in the speed of the forming member be compensated for by adjustment of the quantity of new stock added to the system. Furthermore, unless adequate provision is made, such changes in speed or consistency may cause rapid fluctuations in the uniformity of the finished sheet.

In operation, a certain volume of new stock at relatively high consistency, for example 3 or 4%, is delivered to the system through the pipe l3. This is mixed'with the white water draining fromthe forming sheet into the wire pit.

and usually also with a certain amount of shower water, additional make-up water bein added if necessary. Since in practice there is commonly a small overflow from the wire pit or the supply to the pump I5, any increase or decrease in the volume delivered to the machine can be readily of the :sheet'is affected only by the speed of the wire and by the amount of new stock supplied tothe'system. For example, if the machine is speeded'u p by then it is necessary to increase by 1-0%' the amount of new stock'deliv eredto the system through pipe 13 if the weight of the sheet is :to be kept constant. If it is desired to reduced the consistency of the stock going to th'eslice and the wire, the slice opening may beiincreased, and the volume delivered to the machinecorrespondingly increased so as to maintain the proper pressure at the slice. In accordance with the present invention, two pumps are used in the stock supply system. As

shown ,Fig; 1, the pump I5 takes the 'white water fromrthe'wire pit and the new stock, mixes them thoroughly together and then delivers them to the screening machine for "screening. The second :pumpfl receives the screened stock from the sc'reen collecting chamber, and "by automatic variation of its output delivers the stock to the F slice at-the proper pressure to produce a spouting velocity corresponding to the paper machine speed; This automatic variation is obtained by providing in the screen "collecting chamber 20 a suitable liquid level control adapted 'to regulate the'output of "pump 22, as by regulating its speed, in accordance with changes of level withinfthe screen collecting chamber 20.

If desi'red'the pump I5 may be controlled manuallyb'y the '"operator, or it may be controlled automatically "in accordance with the pressure head effective at the slice by means suchas that shown'intheabove noted Patent No. 2,347,717, Such a control is indicated diagrammatically at 36 as having an electrical connection 31 with pumpliand including'a pipe 38 providing a pressureconnectio-n to the slice. Further, such control of the pump. may likewise be effected in accordance with s'li'ce pressure by the use of the liquid -'level' type control shown in copending applicationof the same inventor, Serial No.6'07,820, filed July '30, -l945,'and assigned to the 'assignee as this application, =now Patent No'. 2,540,301 issued February 6, 4951. l A In the operation of a-machine of thischaracter, theoutput of the first pump I5 is first adjusted to deliver the desired amount of stock to' the screen and the forming member. The output'of the second pump 22 is then automatically ade V j'us'ted to the rate atywhich thestocki flows "into the header from the screen, and to deliver this stock, in the volume determined by the delivery from the first pump, at the required pressure condition at the slice. If after the machine is in operation it is found that the spouting velocity is not in proper correlation with the wire speed, for example if it is slightly below wire speed, thefirst pump may be speeded up or its valve control opened to provide a greater rate of flow. This tends to raise the liquid level in the screen collecting chamber, and the automatic liquid level control will then function to increase the output of the second pump, as by increasing its speed, thus supplying the added volume of now to the stock inlet passage and increasing the pressure and spouting velocity accordingly.

Fig; 2 illustrates somewhat diagrammatically a satisfactory automatic liquid level control mechanism for regulating the output of pump 22 as stated, a more detailed description being found in the above noted Patent No. 2,540,301. In Fig. 2, an extension 40 is shown as secured to the header 20 by means such as a flange H and provides an op'en liquid level chamber 4'4 which-is in free and continuous communication "with the liquid stock within header 20. A suitable power source such as a reversible gear head "motor is mounted in an upright position upon a base plate '46 which is slid'a'b'le vertically up'on'the outer Wall'of extension. Theverticalpositiohof this "plate and the motor relative "to the chamber M is adjustable by means of a manually rotatable screw 41 fitting within the lower wall 'of eiitension 4B and provided with a' suitableniit 48 honrotatably held thereon by means or "the base plate 46. V

The motor shaft '50 extends upwardly ahd ha's threaded engagement with a nut 51 non-rotatab ly held by a bracket "52 which is vertic'ally'slidable upon 'base 'plate 46, suitable guide members being provided on the 'base plate foi' such sliding movement. relation across "theopen end of extension l'oand provides a support for an electrode assembly 55 including a cap'56 of rubber or similar insulating material and a '

pair'of electrodes

51 and 58, suitably'enclosed in insulating tubes leavmg'only'the lower ends exposed. As shown, theseelectrbde's are of difierent lengths, the electrodei'fl being longer than electrode 58 by a predetermined amount, forexar'nple inch. The wires'tfl lead from these electrodes to suitable circuits fo'rcontrolling the output of pump 22, as indicated diagrammatically atfi'l in Fig. 1, and also forc'on trolling the operation of motor 45. This cons'truction provides for raising or loweringbracket 52 and the electrode assembly55 with respe'ct to extension 40 upon operation of the motor. In order to limit-this 'motion, there is provided a pa'ir'of limit'switches 62 and '63 adapted to engage a portion of the bracket and toopen suitable c'ontrol circuits when the bracket and electrode assembly has reached its upperkor --lower'limit of travel respectively.

The connection between the "chamber "4 4* within extension 40 and the interior of header 20 is preferably relatively large, for example of a diameter of 2 inches, so that any changes in the liquid level within header 20 are immediately reflected in chamber-M. -Also,-in-order to prevent stock fibers from accumulating in chambers-4, a small flow of cleanwwater may be allowedto run-into the chamber from a connection fiB su plied froma suitable ex-ternal'sou-rce so thatthere will be a slight flow from chamber'fl into the This bracket '52 extends in overhanging header 20, thus avoiding objectionable deposit oi. fibers within chamber 44.

The wires 60 connect with suitable control mechanism 6| for regulating the output of pump 22, for example by regulating the speed of the 5 pump, and this mechanism also functions to control the operation of motor45, a detailed description and illustration of a suitable wiring diagram being shown in the above noted Patent No. 2,540,301. to hold the liquid in the header 2!] to a level such that the electrode- 51 is immersed in the liquid but the electrode. 58 is above the liquid level. Under these conditions, the pump 22 will operate to deliver a constant output to the inlet 25 and slice, and the motor 45 will not operate. If the liquid level rises sufiiciently to reach the electrode 58, the control circuits will immediately be energized to increase the output of pump 22. At the same time motor 45 will be energized to raise the g0 electrode assembly until the shorter electrode 58' is again out of contact with the liquid, and when this happens the control circuits will be broken, stopping operation of motor 45 and leaving the output of pump 22 constant at the increased rate. 25

The reverse of this operation will take place if the liquid in header 20 drops to a level such that the longer electrode 51 is no longer in contact therewith. The control circuits will then function to decrease the output of pump 22, and at the same time motor 45 will be operated to lower the electrode assembly until electrode 51 is again in contact with the liquid, thus reestablishing equilibrium conditions.

In the operation of the system, the operator will first adjust the output of the pump l5 to deliver the required amount of stock to the screen and the forming member. The output of the second pump will then !be automatically adjusted by means of the electrode controls to deliver all the stock coming to header 20 at a constant rate such that the liquid level within the header 20 is maintained constant as described. If it is found that the spouting velocity at the slice is not properly correlated with the wire speed, or

if the wire speed is changed, the operator adjusts the output of pump I5 accordingly, as by altering its speed or by regulation of valve l8. This adjustment will result in changing the liquid level in header 20, and when this happens the control 56 adjustment of the stock pressure at the slice and so hence of the spouting velocity, which is eflective to give maximum uniformity of flow conditions and particularly to avoid fluctuations such as over-travel or hunting. The control mechanism illustrated in Fig. 2 may be readily adjusted to 5 operate rapidly and in response to relatively slight changes in liquid level, for example within a range of /2 inch or less and with operating periods of the order of a few seconds. At the same time, since the primary control over the volume and rate through the system is obtained by adjustment of the output of pump IS, the invention provides f or maintaining constant and uniform pressure at the slice irrespective of minor fluctuations elsewhere in the system, i. e., fluctua- A normal operating condition is 1 'tions within the range determined by the difference in lengths between the

electrodes

51 and 58. Furthermore, when adjustment of the output of the pump 22 is necessary, it takes place quickly and its output is stabilized at the new rate in minimum time and substantially without additional fluctuation.

The present invention also provides for considerable flexibility with respect to the arrangement of the apparatus, particularly from the standpoint of saving space in the machine room. Since the pump 22 is positioned between the screen collecting chamber and the forming member, there is noneed for the screen [9 and header 20 to be positioned in the machine room, and they can readily be below the machine room floor. This permits a further advantageous rearrangement by which the pump l5 may be eliminated, and the new stock and 'white water supplied to the screen by gravity flow from the regulator box and wirepit, controlled by suitable valves in positions corresponding to valves [6 and [8 on the intake side of the screen and operating in a similar manner. In this arrangement, the operation of pump 22 would still be controlled in accordance with the level of stock in the screen collecting chamber as described.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A stock supply system for a paper machine having a forming member and a slice adjacent the forming member, said system comprising a screen, a header connected to receive stock from said screen, a first pump connected to supply stock to said screen, a second pump connected to deliver stock from said header to said slice and said forming member, a control including a pipe for sensing the pressure of said stock at said slice, an electrical connection :between said pressure responsive control and said first pump for regulating the output of said first pump in accordance with the pressure at said slice, a liquid level control including electrical contacts for sensing changes in the level of said stock in said header, and an electrical connection from said liquid level control to said second pump for regulating the output of said second pump to maintain a substantially constant pressure on said stock as de- 5 livered to said forming member.

2. A stock supply system for a paper machine having a forming member, comprising a screen, a header connected to receive stock from said screen, a first pump connected to supply stock to said screen, a conduit connected to supply white water draining from said forming member to said pump, a second conduit connected to supply new stock to said pump, means including a valve for regulating the output of said pump, a second pump connected to deliver stock from said header to said forming member, a control including electrical contacts for sensing changes in the level of stock in said header, and. an electrical connection from said level control to said second pump for regulating the output of said second pump to determine the pressure on said stock as delivered tosaid forming member.

3. In a paper machine having a forming member and means for collecting the white water aag ma drainin rqm' sairlmrming mamhs g mels $2 39.- .ply system comn fiingffi"gfi n gt to delivgr 51m 12o 5m f gmi z m ant??? a in- Gludin oppcmitsaly ayyanz g tapersd ,f'a

adapted to contain amc f9: e y y t9. $514712;- let, m s c di a p p 9! .mimulafiia said white Water 129 .said header and fer supp y- 111;; new stock t9. 4.191 h a gr 3 115135911; Whifis water, means includin a valve. 9! u at ns till? 7 output (If said pump imluin ,s s nd pu p and a nonduit cgnnectgcl bstwgm id header and said inlet; @9 wppl $9.01: txom said header to said in ei and .sa-id m ipg me gi g a volumetric rate.

'8 EEFEKENQES BREED The follqwing rgference are 9i rec rd 11; the 9 P W Number Nam Bate Warrick Mar. 8; 193B Baxter May 2', 193

Dammann V May 23, 49.4.0

' Lang May 12, 1842 Alling Qct. .6, 19,42 Staege M y 2, 194A Wagner r. Feb. 5', 1,945 Bidwell Dec. 14:, 194

Ens n 2mm $391 1 y 1m gz i mam 99?.- e%, 93