US2162097A - Cylinder paper machine - Google Patents

Description

June 13, 1939. w w METCAL-F 2,162,097

x I CYLINDER PAPER MACHINE Filed Ilaroh 17, 1936 7 Sheets-Sheet l b ...I ...l '.III."

all

June 13, 1939. y wwi METCALF Y 2,162,097

CYLINDER PAPER MACHINE Fled'March 1'7, 1936 7 Sheets-Sheet 2 Junels, 1939. WWMETCALF 2,162,091

CYLINDER PAPER MACHINE v Filed Maren 17. 193e 7 sheets-sheet si June 13, 1939. w w METCALF 2,162,097

CYLINDER PAPER MACHINE Filed March 1'7, 1936 7 Sheets-Sheet 4 June 13, 1939 w. w. METCALF CYLINDER PAPER MACHINE Filed March 1'7, 1936 'r sheets-sheet s /Nx/NTUR m n Lgf/@WAM A 7' TOR/var June 13, 1939. w w METCALF 2,162,097

CYLINDER PAPER MACHINE Filed March 1'7, 195e 7 sheets-sheet e June 13, 1939.

7 sheets-sheet r Filgd March 17,

Q J w l il m 7 /7 Arrow/Vey 1 muy in section, showing the details of the decine plate adjustment;

Fig. 8 is a fragmentary sectional velevation takenv in a plane normal to the axis of the cylinder mold and showing the methodof sealing the u vat against the entrance of air at the end of the mold; v

Fig. 9 is a fragmentary plan view of the parts shown in Fig. 8;

Eig. 10 is a plan view of l detail of the'air `sealingmeans;

Fig. 11 is a fragmentary diagrammatic elevationfview of a device for indicating the head of stock in the vat and the velocity of the stock at the-entrance to the web forming zone; l A

Fig. 12-isaplanv'iew of a preferredY type of instrument used toindicate the head on the vat and the'lspeed of .the stock entering the zone o f formation L ng. 41a is an elevation n; seccion,

l ofthe instrument 'shown'in' Pig; 12g; n

Fig. 14 is a'fragmmtary front elevation of the Vinstrument shown in Figs. 12 and 13;

Fig. 15 is a diagrammatic, sectional elevation view showing two of my molds arranged in tandem for the'production of`a two ply web; and

Fig. 16 is a section of Fig. 15 in either the plane IS-II or |-1|1 illustrating a section throughthestockduct. j'

' Referring to the drawings, represents a cylto removegthe web from the mold in amanner well understood inthe art. Stock isv supplied to the mold V| from the body of the vatV where the stock is maintained vat a level 5 suflicient to provide the required static and velocity head for web formation. A duct 6 having the sides of the entrance well rounded, as at 1, extends upwardly from the lower portion of the vat under the roll and servesto convey the stock to the mold. The ductl l is inclined upwardly to avoid any possibility of surging flow occurring therein due to the presence of `entrapped air in any low pockets. The cross section'of the duct 5 is gradually decreased in size as it approaches the mold so that the stock flowing therein has a gradual and smooth acceleration `in velocity in its'passage to the mold. These precautions are taken to minimire the losses due to hydraulic friction and to maintain, as far as possible. the random arrange- Vment of fibers that exists inthebodyV of the stock in the vat. At a point somewhat below the mold, the duct i turns upwardly, as at I, and continues'into a nozzle `section designated geny erally by the numeral 3. The inner side of the duct which isv'aaidjacent the mold terminates at a point/'I0 above the level ofthe white water within the mold and vat,v so that the entire web formation takes place abovethis level. The terminating portion of this side of the duct is formed as follows (see Figs. 1 and 2):

An angle I l is bolted to the duct and its legY 2 is recessed into the side of the duct so that the outer surface V|3 is flush with the inside of the duct below.- Bolted to the angle is a second inder mold rotatably mounted invat 2. 3 is the Y usual couch roll and 4 is the felt which functionsbuckles 43, and 49 with angle i4 having a standing leg i5 whose extremity closely approaches the surface of the mold and is beveled as shown at ii. `I1 is a rubber apron, the free end il of which runs in contact with the surface of the mold '111e bottom portion i9 of this apron is secured between the back of the leg l5 of angle i4 and a micarta n plate 2d, the outer surface ofV which lies in the same plane as the outer side of the angle H.

v The upper end of thernicarta plate 2|) is beveled articulated 'sections so that it maybe moved relative to the mold in order to vary the cross sectional` area of the nozzle section, and also swing back to provide clearance for the removal of the mold. The fixed portion ofl the outer wall of the'duct Aadjacent the nozzle Section terminates in a micarta plate'26 secured to the end of the duct by means of screws 21. Secured by bolts or otherwise to the inside end of Y thei vat are bearings 23 in which is mounted a shaft 23 extending across the yat.

Links 3l are also pivotally mounted at one end on the shaft 29 and pivotally connectedV at the other end, by means of a shaft 3|, to ele-` ments 32 to which is secured a curved face plate 33 forming the rear portion of the nozzle section. A plate 34 extending across the vat is secured to the links 33 ,and has its` lower portion bent to Va cylindrical surface having the center of shaft 29 as an axis. Thegmicarta plate 26 is tangent to this curved portion of plate 34. Like,-

wise, the lower end of plate 33 is bent to-formY a cylindrical surface having the center of the shaft 3| as an'axis, and a second micarta plate,

35, secured to the plate 34 by means of screws 36,

has its free end 31 beveled and contacting the curved portion of the plate 33. It is to be understood that plates 26, 35 and 33 have smooth polished surfaces and together form the back Wall of the nozzle section of the duct which is free of any abrupt changes in curvature.

Extending across the vat to the rear of the nozzle are horizontal shafts 38 and 39 (see Fig. D

on which are mounted eccentrics 40 and 4| respectively. Rotatably mounted upon the eccen-` trics are bushings 42 and 43 provided with pro jecting pins 44 and 45. Hook elements and 41 having openings therein adapted to receive respectively the vpins 44 and 45V are simply supported on the bushings 42 Aand43. .The hook elements 46 and 41 are connected byv means oftum respectivelyrotatably mounted on shafts`52 and 3| respectively; it being understooda that the shaft 52 extends across the vat and is rotatably mounted in the bearings 53 on elements 32.

Referring particularly to Figs. 4 and 5, the shafts 35 and 39 are mounted in suitable bearings secured to the sides of the vat and have worm Wheels 54 and 55 secured thereto. Worms 55 and 51 cooperate with the worm wheels 54 and 55 respectively and may be turned by means of the hand wheels 58 and 5S, respectively, to effect a ables.

i or adjusted to secure the best operating conditions. By simply lifting the hooks 46 and 4l off the bushings 42 and 43, the entire back wall of the nozzle section may be swung back away from the mold.

The members 30 and 32 are so assembled that they constitute a rigid, non-flexible outside wall confronting the mold in the zone of primary web formation. The face 60 of the element 33 is so shaped that the velocity of stock fiow in the forming zone is at all times under the control of the operator, and proper shaping of this face is very important because it has a great deal to do with the success of my device.

In designing the nozzle section of my duct and particularly the face 60 of element 33 I proceed as follows:

First: I determine, experimentally, the variations in the rate of water flow through wire cloth of the character used on the face vof the cylinder mold and through a newly formed sheet thereon when the amount of fiber in the sheet, expressed ln bone dry weight, and the head or pressure causing the flow, are known and controlled vari- 'Ihese data will vary with different stock and stock treatments and hence it is advisable to make rather extended experiments to arrive at a true understanding of the values concerned for a particular design problem.

It is found from consideration of such expen'mental data that: y

(a) The rate of vflow through a forming sheet under constant head varies with the weight of the sheet according to a definite exponential relation which is described in mathematical parlance as the law of organic decay or logarithmic decrement.

This may be expressed in a mathematical formula as follows:

'I'he rate of flow is a decreasing function ofthe sheet weight, the independent variable.

(b) The rate of flow through a sheet of con- Ystant weight is proportional to some power, be-

tween 1/2 and l, of the head acting to cause the flow.

This may be written as a formula:

F=CH

Where F denotes rate of flow per unit of area, H denotes head,

:c denotes the power of the head, and C denotes a constant.

The experimental data also show in a quantitative way the variations in value of :c for variations in weight.

(c) The limitation of the rate of flow may be due to the wire cloth or to the sheet itself: whichever of these is the smaller establishing the limit.

Thus for very light sheets, or in the early stages of formation of any sheet, it is necessary to consider the rate of flow that will occur through a bare wire. Experimental determinations of these values for various heads are essential to predict conditions of zero on light sheet weight in anycase.

Consideration ofthe experimental data indicates that the ow through la forming sheet is of a mixed turbulent and capillary nature, inasmuch as for calculationsfo'fflow, the exponent of the head used for turbulent'flow is 0.5, and for capillary flow 1.0. The exponent is near the low value for a thin sheet and approaches the high' value for a thick sheet. With a definite sheet weight the actual value of the exponent is an indication of the part of the ow which ls of a turbulent nature and the part' which i's"capillary. An assumption of the existence of some' capillary flow during formation agrees with commomknowledge that the freeness of stock is chang'dd by change of temperature'o'f the water in the stock suspension.

Second: Adesirable and practical zone of formation on a defined mold surface is assumed and the rate of flow and Weight of sheet that will exist at all points 'through the zone of formation are calculated. To make this possible as a definite problem certain knowledge and assumptions are necessary, as follows:

(a) The quantitative experimental data above described. l

(b) The pressure conditions at all points in the zone of formation, which necessitates an assumption of head, or the elevation of the stock in the vat, as shown at 5 in Fig. 1, and the internal mold suction.

(c) A definite and desirable uniform consist-- ency of stock.

(d) When a definite amount of ber is removed from a definite amount of water and spread uniformly over a known area the resulting sheet weight can be calculated. Y

(e) From the experimental data, the rate of flow at any point is known when the weight of sheet and head are established.

(f) The velocity which is desired throughout the formation zone is assumed as uniform and constant in value. It is necessary to know and establish this because of the interrelationship of velocity and static pressure.

To facilitate calculation, a method of approximate integration and trial and error is adopted. The zone of formation is first divided into a suitable number of smaller zones, and, for calculation', the sheet weight and hence the rate of flow assumed constant for each of the Y smaller zones. As considered at firstthe ysmall zone does not have a known length and defined position in the entire formation zone but is rather that zone where the sheet gains a known increment of weight. By assumption, the rate of flow while in the zone and the increment of weight is known, the length of time in, and hencethe length of travel in the zone, can be calculated; The mold speed is uniform and known. The length-of each zone and the weight in each zone being thus progressively determined, sufficient information results to determine the sheet weight at all points of travel through the zone as a whole.

With the results of the first calculations, the work is repeated with the approximately correct values for head and rate of flow substituted for thoseassumed in the first calculations. The re suits of several series of such calculations will be progressivelyclor to the true valuesand a finalv result is obtained and within. the -limits of vnece:sary accuracy. It maybe n to repeat the first vcalculations several times by making necessary changes in the assumptions to obtain `a resulting formation, lengthjof travel or sheet weight that is more desirable for design. These resulting values are changed by changing the assumed values for consistency, or head and suction. l Finally, a result is attainable which show a denite and desirable final sheet weight :a definite length of formation surface used; the weight of the sheet at any point of its travel in formation (in the embodiment sho'wn,-vthe last mentioned result is presented in graphical form, in Fig. 3f as the relationship of percentage formation with percentage of mold travel); and a consistency and rate of stock flow to form the sheet.

Third: 'Ihe next step is to calculate the dimensions or and establish the shapev of face so of member 22. This can be determined because the spacing oi' theface 0I from the mold at various points can be calculated as follows:

(a) Determine the width of section at the .point of inlet intothe nozzle where formation starts which m necessary to pass the determinedamount of water at, the assumed and predetery mined uniform velocity. 'I'his dimensionis hereinafter referred to as inlet width and in mostcases t will vary from 5i" tcl8/4".

(b) At the point where of the sheet weight has been formed 90% of the stock admitted is still left in the space between the mold and the face 60, andr hence. to maintain the uniform stock velocity decided upon, it is necessary that the distance from the wire to the face 6l at this point be 90% of the inlet width. In the sam'e way, with of the sheet formed, 50% of the initially admitted stock is left in the nozzle, and the width of the nozzle at this point should be 50% of the inlet width. With a sufllcient number of points so determined a smooth curve drawn therethrough will fix the shape of the face 60.

' VI have found from actual experience in the development of my device that although the calculations for determining thev curvature of the face Il are all based on one stock condition, one weight of sheet, one consistency of stock, one rate of flow, and one speed, the same curvature may be used for stocks of 'different freeness, for different sheet weights and for different speeds by moving the face 00 either towards vor away from the mold, and the resulting sheet formed will be of acceptable character when the face is properly positioned and the rate of flow adjusted thereto.

In operation, since it is not necessary or always desirable that the stock velocity be uniform or equal to the moldspeed throughout the formation zone, the necessary adjustments of velocity', and hence of sheet characteristics can be made by moving element 22 as a unit. The actual shape of the `face ll will probably be slightly in errorfor conditions other than those considered in its design, but in operation the error is so slight that it may be neglected.

Instead of maintaining a partial vacuum within the mold only, as has heretofore been common, I maintain a partial vacuum not only within the mold but also within a portion of the vat adjacent thereto. In other words, the vat is practically sealed against the entrance of air at all Il, and the usual rubber strap i3 overlies these rings to prevent the entrance of air therebetween. It is not necessary that this strap be carried down below the normal water level in the vat, represented by the line 6I in Fig. i, in order to seal the mold atthe'ends because the lower part of the vat itself is substantially sealed against the entrance of air as will be hereinafter described.

When in operation, that portion of' the cylinder mold between the nozzle section and the pinch 64 of the couch roll is covered with the forming paper web. Behind the couch roll is a shower pipe l5, the water from which substantially seals the mold against the entrance of air from about the point 65' to the point 60 where the rubber apron 81 runs in contact therewith. At the sides, the mold and vat are sealed against the entrance of air by means of the rubber straps 6J which extend, as shown in Figs. 8, 9 and 10, from the point 66 to the point Il below the noz- `zie section. Thus, air enters the vat only through that portionY of the mold peripheryy extending between the pinchof the couch roll and the shower from pipe, and sufficient space must beleft here to prevent the entering air from attaining such a high velocity as would injure the wet web on felt l. It may be noted here that the admission of air at this point has the advantage of relieving to some degreethe suction holding the web against the surface of the mold at the point of couching, thus allowing the web to be more easily removed bythe felt.

Referring to Fig. 1, 68 is a slice board located in the conventional manner of the art, and a shower pipe 10, above the slice, supplies additional water' to the nip when necessary.

White Water leaves the inside of the mold through the both ends thereof and exit ports in the sides of the vat 2 and also outwardly through the wire cloth into the chamber 1|. The water is drained from chamber 1I through ports 12 in the sides of the vat. 'I'hese ports are located below the water level 14 in the chamber 1| which thus provides a suction seal and prevents the passage of air through these ports. It has been found desirable that the external suction connection be made within the end area of the mold rather than in the chamber 1I, and air passes to the exhaust fan (not shown) through port 15 at the rear of the vat.

Referring now to Figs. 4 and 5, white water from openings 12 and 15 (see Fig. 1) flows into two compartments or boxes one at the front and one at the rear of the vat. These compartments are connected by an equalizing passage 16 formed between the bottom of the duct 6 and the bottom and ends of the vat 2. This passage 1l is provided with a vent or breather pipe 11 to allow the escape of trapped air whenstarting. The' end white water compartments 1I and 19 are provided with sealing covers I0, and the spaces therein above the water line as well as the inside of the mold and the chamber 1i are under suction. White Water is allowed to leave the compartments mentioned above only by flowing under partitions 8| which provide an eective and simple seal for the suction. After passing 75 vhead 5 (see Fig. 1) in vat 2.

amaca? partitions 8|, the white water is exposed to atmospheric pressure.

White water is allowed to pass away from the vat through pipe 82 communicating with the white water box on the front side of the machine. The height of pipe 82 is such that the water level 14 in the vat is satisfactory and below the zone where stock is initially delivered to the mold. In

operation no adjustment of this white water level is necessary. Thus the necessity of having float valves, adjustable weirs, etc., which have been Vin commonuse in the art for many years, is eliminated.

White water from the rear compartment may enter either of two kpipes 83 or 84. Pipe 84 communicates with a pump 85 and with a screen (not shown) so that the white water is thus recirculated to mix with the incoming thick stock before straining. The location and type of screen is conventional.

Pipe 83 leads to the circulating pump 86 which delivers the stock into the vat through the regulating valve 81. A pipe 88 joins the pipe 83 before passing into the suction opening of the pump 86, and screened stock is admitted to the circulation at this point through pipe 88. y

Valve 81 serves to control the amount of stock circulated in gallons `per minute and hence the lIfhis is true since an increase or decrease of head 5 will cause a corresponding increase or decrease of drainage 'through the forming web. Hence, at any one setting of valve 81 a condition of equilibrium will be established where the head 5 becomes substantially stationary. l

Members 89, 90, 9| and 92 are conventional bailies arranged to guide and quiet the ow of stock as it passes through the body of the vat from inlet valve 81 to the entrance of duct 5.

40 The nozzle section is sealed at the ends by deckle plates 83, preferably of micarta. These plates are pivoted at the bottom on shaft 29 and are yieldingly held against the sides of the nozzle section by helical springs 94 surrounding the ends of shaft 29 and compressed between the plates and washers v95 secured on shaft .29 by means of pins 96. The shafts 3| and 52 terminate adjacent the deckle plates 93, as shown atv 91 and 98 in Fig. 7. The ends of these shafts are drilled and threaded to receive the threaded portions 9 8 and |00 of the clamp screws |0| and |02 which serve to clamp the deckle plates 93 against the ends of the nozzle section of the duct 6. The threaded portions of the clamp screws pass through large openings |03 and- |04 in the deckle plates 93 and the bases of the clamp screws are enlarged as shown at |05 and |05 where they bear against the outside of the deckle plates. By loosening the screwsand |02 the deckle plates 93 have a limited swinging movement about shaft 29 because of the clearance between the threaded portions of the screws and the openings in the deckle plates. Thus the deckle plates may be adjusted to run very closely to the surface of the cylinder mold independently of the position of the outer wall of the duct.

The width of the duct 6 may be varied to some extent by means of movable blocks |01 at either side thereof. These blocks fit closely Within the duct and may be moved by the hand wheels |08 which turn stems ||0 passing through the sides with plates H3 secured to the blocks |01, as shown. Y

Referring particularly to Fig. 11 in connection with Fig. 1, I have here shown a simple device for indicating the head of stock in the vat and the velocity of stock now in the nozzle section of the duct. |40 is a glass tube, open at the top and communicating at the bottom by means of a tube |41, with the body of the stock in the vat so that the water level in the tube |40 indicates the level 5 of the stock in the vat.

|42 is also a glass tube, open at the top, and somewhat longer than tube |40, which communicates at the bottom through a pipe |43, a flexible tube or hose |33 (see Fig. 1), and a short tube |34, with the stock flowing in the nozzle section of the duct. The inside end of the tube |34 is ush with the surface 60 forming the outer or back surface of the nozzle, and the tube itself is disposed normal to this surface. AThe level of the water in tube |42 therefore indicates the static However, the difference in the water levels intubes and, |42 may be and is used to indicate the velocity of stock now in the nozzle at this point provided proper allowance is made' for losses due ,to hydraulic friction whichmay be determined by the use of Pitot tubes.` Such losses usually do not exceed a'small fraction of an inch of water.

The tubes |40 and |42 are mounted closely together and used in connection with two scales |44 and |45. The scale |44 is fixed and graduated in inches from a zero level, arbitrarily positioned, to indicate the level 5 of the stock in the vat. The scale |45 is mounted between the tubes |40 and |42 so as to be vertically slidable and is calibrated and graduated to indicate, in feet per minute, the velocity of stock ow in the nozzle. In use, the scale |45"is vertically adjusted until the zero index corresponds with the -water level in tube |40 whereupon the stock velocity may be read opposite the water level in tube |42.

In Figs. 12, 13 and 14 I have illustrated a more desirable type of instrument than that shown in Fig. l1 whereby the velocity of stock flow in the nozzle may be read at any timewithout the necessity of manually moving and adjusting a sliding scale to compensate for variations in the head 5 of the stock. In this instrument, variations in static head are automatically compensated.

the end of the reduced portion an indicating hand or needle |22. Secured to the rear end of the shaft |20 -is a sprocket wheel |23 over which rides a chain |24. The sprocket wheel is so clisposed with relation to the tubes ||8 and ||9 that it is substantially tangent to the axis of each tube. The chain |24 thus depends substantially in the axes of the tubes and weights |25 and |25 are suspended from the ends thereof and within the tubes ||8 and H9, respectively.

Surrounding, and out of contact with the reduced portion of the shaft ||5, is a sleeve |21 Les which is rotatably mounted in bearings |28 and |29. Secured to the outer portion of this sleeve and just behind the needle |22 is a movable dial |30. Also secured to the sleeve |21 is a second sprocket |3| by which it is turned independently of shaft ||5. The sprocket |3| is so mounted with relation to tubes lli-and that it is substantially tangent to the axis of each tube. A second chain (not shown but in all respects similar tochain |24) rides over this sprocket and there are weights at the extremities thereof and within the tubes ||6 and similar to the weights |25 and |26 in tubes ||8 and H3.`

Tubes and ||3 are open at the bottom and serve merely to protect the movement of the weights therein. On the other hand, tubes ||5 and H3 -contain liquid and may be considered 'analogous to the tubes |40 and |42, respectively. I'he tube lli communicates at the bottom through a pipe |32 with the stock in the vat and the level of the liquid in the tube I6 indicates the liquid level 5 in the vat. The small .pipe extending from the bottom of tube Hl com'-,v @mi fmunicates through the hose |33 (see Fig. 1) *withA f the small tube |34 opening into the nozzle portion ofY the stock duct in the same manner as n described abovein connection with tube |42 (see Flg..11) The level of the liquid therefore in tube III will indicate the static pressure in the nozzle portion of the duct at the'point where the y tube |34 communicates therewith. 'I'he weights in tubes ||5 and ||3 are somewhat larger than their companion weights in tubes ||1 and H9 so thatthey will move downwardly with a fall yin the water level in these tubes. On the other hand, they are not as large that they will not be y. ybuoyed and carried up by a rise in the water level.

a The fixed dial |35 (see Figs. 12 and 14) is graduated to indicate in inches, above an arbitrary zero datum, the water level 5 in the vat. Pointer |22 which is rotated by sprocket |23 through shaft ||5 indicates the depth of the water in tube. Il and hence the static head in the nozzle.

The dial |33, which is turned by sprocket |3I, carries; a zero index and an arrow at this index which always indicates on the xed dial |35 the head of stock in the vat. From this zero indexthe dial is calibrated and graduated, in a counter-clockwise direction, to indicate the velocity of the stock flow in the nozzlein feet per'minute, by the position of the hand or pointer |22 thereover.

From the foregoing it will be apparent that the ilxed scale |35is analogous to the fixed scale |34 shown in Fig. 11 and that the movable dial |33 is analogous to the slidably movable scale |45-of Fig. 11. In this latter type oi' instrument, however, instead of manually moving the sliding scale in order to bring the zero index coincident with the head of water in the vat, the dial |30 is automatically moved in accordance with variations in the head 5 and the arrow at the zero index always indicates the head 5, and thus the stockfvelocity of feet per minute may alwaysv be read'directly from the movable dial.

In operation, I find that very satisfactory results are attained if the side of the duct adjacent the mold, as represented by the micarta plate 22, is inclined to the mold at an angle of about 15 degrees to the tangent at the point of initial delivery of stock. Furthermore, the outer wall 60 of the duct should extend around a subin order that the jet parabola may conform sub stantially to the curvature of the periphery of the mold. The angle of release depends to some extent upon the diameter of the mold and where the jet is released at too great an angle tothe horizontal, the radius of curvature of the jet parabola becomes too small to approximate the curvature of a mold of practical size.

In a machine of this type it is desirable that as much as possible of the web formation takes place within the nozzle section. Ordinarily, about 90% of the formation Will take place within the nozzle and the balance, or 10%. just beyond the end of the nozzle.

Within the nozzle where the major portion of the sheet is formed, it is under the control of the operator through the medium of a variable head and adjustment of the face 60 of the nozzle. In order to secure perfect sheet formation beyond the nozzle section, the velocity at 'which the stock is released from the'nozzle must be selected and controlledy so that the jet, moving as a free body without restraint or deflection describes a paraboloid closely approximating orcoinciding with the circular surface of the mold.

Vlocated very close to the wire cloth on the cylinder mold and this requires accuracy of manufacture and initial adjustment of the surface. 60 in order to attain, with precision, an opening or gap across the mold face which will be substantially equal at all points. The distance between the surface 60 and the Wire cloth surface of the mold at the tip of the nozzle will ordinarily run between 0.06 and 0.2 inch, and to maintain this gap constant while the mold is rotating, it is essential that the mold vbe precisely cylindrical and rotate on its axis without eccentricity. In operation, there are only three controls which render the adjustment extremely simple. With the speed in feet per minute of the moldv being known, it is possible by means of the instrument shown in Fig. 11 or that shown in Figs. 12, 13

and 14 to adjust the stock flow in the nozzle in the desired relation to the mold velocity by means of valve 81 which controls the head of stock in the vat and by means of hand wheel 59 which will move the inlet of the nozzle toward or away from the face cf the mold. Having properly positioned the lower portion of the face 60 of the nozzle the discharge end is adjusted by means of the hand wheel 58 by observing the water line at the end of the web formation beyond the nozzle. Since the face 60 is designed, in accordance with the principles aforesaid, so that the cross section of the nozzle diminishes in size substantially inversely proportional to the web formation, it automatically takes care of conditions intermediate the two points of adjustment.

The embodiment of my invention described above is for use on a single cylinder machine, but with certain minor modiications the device may be applied tomulti-cylinder machines. The principal modification necessary being to locate the vat in a position other than beneath the felt and to eiect the necessary changes in the shape and location of the fixed conduit section which conveys the stock from the vat to the nozzle section. This permits the pick-up felt to pass directly from one formation to the next in the usual manner known in the art.

Referring particularly to Fig. I have here shown in a more or less diagrammatic way, two cylinder molds arranged in tandem for the production of a two ply sheet. All of the parts here shown are substantially identical with the correspondingly numbered parts in the other figures of the drawings. Here, however, the ducts which convey the stock to the nozzle section are shown at |50, the same number being used for each duct because they are identical. These ducts extend transversely across the machine and are fed from vats i5| at the sides. In order that the stock may have a uniform velocity of movement toward the nozzle sections within the ducts, the cross sectional area of the ducts is smallest at the end |52 remote from the vat, as shown in Fig. 16. In other words, the bottom |53 of the duct slopes downwardly from the end |52' toward the vats. The tops of the ducts are closed, except at the nozzle section, by mic'arta plates |54 which are beveled at their ends |55 where they 'form a substantially sealed joint with the element |56 on the nozzle.

lWhile I have described my invention in its preferred embodiment, it is to be understood that the drawings are merely illustrative and that the words which Iv have used are words of description rather than of limitation. Hence, changes within the purview of the appended claims may be made without departing from the true scope and spirit of my invention in its broader aspects.

What I claim is:

l. In a paper making machine, the combination with a vat, of a cylinder mold rotatably mounted therein on a horizontal axis, means cooperating with said mold for removing the paper web therefrom, means comprising an inner wall adjacent said mold and an outer wall spaced from said inner wall to form an upwardly extending duct for delivering stock to said mold, said inner wali terminating in close proximity to the surface of said mold on the ascending side in a zone substantially above the bottom thereof in whichsad zone stock is initially delivered to said mold, said outer wall extending upwardly beyond said inner wall around a substantial portion of the upper ascending quadrant of said mold and comprising a rst rigid wall section pivotally mounted at its lower end to swing toward and away from said mold and a second wall section having its side facing said mold preformed to a definite, fixed contour merging smoothly with the mold-facing surface of said first` seot'ionfand piv otally connected to the upper end. of said first' section whereby it may swing with said iirst section or independently thereof, means cooperating with said wall sections for swinging -them towards or away from said mold, and means for rrizaiintaiining` the white water level inV said mold entirely below the level of the zone within which stock is delivered to said mold. from said duct; the topmost and terminating edge of said second section being spaced from the zone of web removal from said mold and the path of the moving stock and partially formed web being free andunobstructed between said edge and said removal zone.

2. The structure set forth in claim 1 in which. the preformed contour of the second wall; section' and the means cooperating with said wall sections ior swinging them towards or away from said mold are so correlated and arranged? as: toA permit said second section to be positioned. rela, tive to the surface of said mold to dene therewith a duct having a cross sectional area decreasing. in the direction of stock ilow at substantiallyvthef same rate as the web formation increases throughout said duct.

3. The structureset forth in claim l in which the upper and terminating edge of said second wall section is. located at an angular distance from the top center of the mold of from to 40.

4. The combination with the structure set forth in claim 1, of deckle plates cooperating with said mold and with said wall sections for substantially sealing the sides of said duct, and means for movingl said plates independently of said wall sections.

5. In a paper making machine of the character described, the combination with a vat, oi a cylinder mold rotatably mounted therein on a horizontal axis, means forming a duct for delivering stock to said mold, means for indicating the ilow velocity of the stock in said duct in a zone near the zone of initial delivery of said stock to said mold, and means for varying said velocity.

6. In a paper making machine of the character described, the combination with a vat, of a cylinder mold rotatably mounted therein on a horizontal axis, means forming a duct for delivering stock to said mold, means controlled by the static head of stock in said vat, means controlled by the static head of stock in said duct in the zone of stock delivery therefrom to said mold, and means for indicating the differential in said static heads whereby the ow velocity of the stock in said zone may be ascertained.

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