US3065788A

US3065788A - Multiple pipe stock distributor

Info

Publication number: US3065788A
Application number: US830238A
Authority: US
Inventors: Edward D Beachler; Louis E Dennis
Original assignee: Beloit Iron Works Inc
Current assignee: Beloit Iron Works Inc
Priority date: 1959-07-29
Filing date: 1959-07-29
Publication date: 1962-11-27
Anticipated expiration: 1979-11-27
Also published as: FI45415C; SE327130B; FI46415B; GB941577A

Description

Nov. 27, 1962 E. D. BEACHLER ET AL 3,065,788

MULTIPLE PIPE STOCK DISTRIBUTOR Filed July 29, 1959 2 Sheets-Sheet 1 u g m 8 8 a; Q) 5 L1. as

l I an a I I O l I l .0 n1 0 I 1 z I I; u H 4 :51 l *q L I #3 Q u m f m 8 9\,Q 6

w a Q I INVENTORS EDWARD D. BEACHLER LOUIS E. DENNIS A ORNEYS Nov. 27, 1962 E. D. BEACHLER ET AL 3,065,788

MULTIPLE PIPE STOCK DISTRIBUTOR Filed July 29, 1959 2 Sheets-Sheet 2 32 0 O O O O 41 b f M A CONT. 8 V V MECH. o o 0 40 o M) O 0 0 39 o QJ A L /37 13b INVENTORS EDWARD D. BEACHLER H64 LOUIS E. DENNIS States t The present invention relates broadly to a stock distributor assembly for use with paper making machines, and is more particularly concerned with a flow spreader or distributor means to transform a narrow fast flowing stream of stock into a broad flat stream moving with uniform velocities into the entire width of the paper machine flow box.

Even distribution of stock fibers across the entire Width of the forming surface of a paper making machine has long received the attention of those skilled in the art, and among the solutions proposed and/ or used are multiple channel systems in which the flow is divided and redivided, or cross flow devices in which the oppositely flowing streams of stock merge in order to cancel the cross velocities. Other structures have been proposed in which the stock is delivered in a continuously moving flow Without substantial change in velocities, and at present such devices are largely deemed impractical. Many of the structural arrangements suggested or in actual use then suffer from one or more of the disadvantages of generally ineffective uniform stock distribution, undue complexity, or inability to cope with the increased speeds of modern paper making machines.

It is accordingly an important aim of the present invention to provide an improved stock distributor assembly avoiding the named and other objection and disadvantages, and wherein velocity and pressure energies are redirected to eliminate substantially all components therein which are transverse to the paper machine direction.

It is a further object of this invention to provide a stock distributor assembly and method of spreading a stock flow wherein a supply stream of papermaking stock being delivered to a paper machine is successively accelerated and decelerated and subject to such friction forces as will substantially diminish upstream pressure pulsations to provide a stock supply entering the full width of the flow box in a condition of flow essentially free from major turbulence and uniformly well dispersed.

Other objects and advantages of the invention will become more apparent during the course of the following description, particularly when taken in connection with the accompanying drawings.

In the drawings, wherein like numerals are employed to designate like parts throughout the same;

FIGURE 1 is a sectional elevational view of a stock distributor constructed in accordance with the principles of this invention and connected to a typical paper machine inlet flow box;

FIGURE 2 is an end elevational view of the feed distribution header, vertical risers and associated structure of the stock distributor assembly;

FIGURE 3 is a vertical sectional view taken substantially along the line IIIIII of FIGURE 2; and

FIGURE 4 is a diagrammatic showing of a stock redistribution system which may be employed in connection with the assembly herein disclosed.

Referring now first to FIGURES 1 and 2 of the drawings, there is shown a stock distribution system generally designated by the numeral and comprising stock supply or first conduit 11 of relatively small cross-sectional area and width receiving a high velocity stream of stock and connecting with a stock inlet box or chamber 12 of relatively larger cross-sectional area and width accommodating a relatively slower flow of stock. The conduit 11 and 3,%5,788 Patented Nov. 27, 1962 inlet box 12 communicate by means of a feed distribution tube or header 13 mounting an array of relatively small diameter, transversely closely spaced and generally upright risers or tubes 14 providing a relatively high velocity stock flow to a blending chamber 15 wherein a velocity reduction is effected prior to direction of the stock through a reacceleration throat 16 communicating through a deceleration conduit 17 with the inlet box 12 and generally transversely coextensive therewith.

The general structure of the inlet box 12 is shown in FIGURE 1, and it may be seen therefrom that the headbox is defined by a generally horizontal floor 18 suitably mounted on a rear supporting frame 19a and a front supporting frame 1%, both of which are supported by the operating floor G in the usual manner. The inlet box or chamber 12 is further defined by an upright rear wall 20a, side walls 2% on the back side and a front side wall (not shown), and a forward wall structure 200 carrying a slicedefining element 20d cooperating with an apron 1811 carried by the floor 18 to define the outlet slice gate, from which stock flows unto a traveling forming wire W turning over a breast roll B in the usual manner.

The inlet or flow box 12 is further provided with a plurality of rectifier rolls 21 of known construction, the roll 21a being positioned in close running relationship with the floor 18 and wall portion 20a of the forward wall structure 200 to be in the path of stock flow passing into the slice S. A second rectifier roll 21b is located generally in the middle of the inlet box 12 between the forward and rear walls thereof in close running relation with the floor 18.

The fiowbox 12, as will be appreciated by those having knowledge of the art, is adapted to a limited range of papermaking conditions. The length, depth and other dimensions of a paper machine flow box are determined, among other things, by the intended speed of operation and by the characteristics of the grades of paper to be produced. The distributor 11 of this invention may be 7 applied to any flow box or inlet used in the Fourdrinier type of paper machine in the vatcylinder mold type of paper machine, or other known types.

The inlet box 12 is also provided with a bottom opening 22 extending the full width of the box and opening downwardly therefrom along the rear wall 20a. A rectifier roll 210 is mounted in close running relation to the wall portions defining the bottom opening 22.

The flow distribution tube of header 13, which mounts the delivery tubes or risers 14 and which provides a stock flow path thereto from the conduit 11 fed by a suitable pumping device, is shown in FIGURE 2 as of tapering cross section from one end to the opposite end thereof. This has the advantage that, when an end delivery system is used, the stock flow velocity in all risers will be approximately the same, and of course in this event the header 13 is suitably sized to compensate in part for the reduced volume of stock moving therethrough in accordance with the quantity of stock removed by the successive multiple tubes 14.

In the structural arrangement illustrated, the conduit 11 and delivery end 1% of the header 13 have an inner diameter of approximately 20 inches, whereas opposite end 131) of the header has an inner diameter of about 12 inches. This has been found to provide the desired essentially equal stock flow velocity and velocity head loss in all delivery tubes 14. The number, inner diameter and length of the delivery tubes 14', as well as their spacing along the header 13, will vary depending upon a number of factors, including machine speeds, pumping power required, construction economy, and the like. In work performed to date, however, particularly satisfactory results by way of uniform stock distribution and consequent reduction in the variation of the basis weight across the machine have been obtained when the following relationships are maintained. First, the sum of the diameters of the tubes 14 should be slightly less than one-half of the distance between the pond sides or inlet box side walls 205, A minimum sum of the tube diameters is about one-fourth this distance, and the maximum is limited by the economies of construction to avoid a close sidewise stacking of the tubes. Second, the present optimum length to diameter ratio of the tubes is 13 to l, and this is fulfilled in actual practice by employing tubes 30 inches in length having a two and a half inch diameter. In this relationship, the minimum ratio is not substantially less than 7 to l, and the maximum ratio is about 25 to l, or as dictated by the pumping power required. In this connection, thirty-six delivery tubes 14- equally spaced along a 20 foot header 13 is a desirable practical arrangement.

The header 13 is positioned just above the delivery conduit 11, so that there will be upward fiow of stock from the conduit into the header, and said header extends the full width of the inlet box 12. The header 13 is conveniently positioned above the paper machine operating fioor and receives stock through the delivery conduit 11 from pump means (not shown) located on the floor below. In any case, there should be a generally upward flow of stock from the pump means to the header 13. By the use of a long radius type elbow 11, stock is delivered to the tapered header along the length thereof so as to provide substantially similar velocity and pressure conditions at each entry to the several tubes 14. The stock is then forced generally vertically or upwardly into a pattern of essentially parallel streams provided by the multitude of relatively small diameter and substantial length laterally spaced risers or delivery tubes 14. The tubes 14 guide the stock flow perpendicularly from the header 13 andconvert the energy to substantially velocity energy directed in plane parallel to the transverse axes of the paper machine, effectively reducing the velocity components transverse to the machine direction. By substantially increasing the stock flow velocity by a factor of about two, through provision of a reduced cross sectional area path, the risers or tubes 14 substantially accelerate the flow of stock, thereby promoting a desirable fine scale turbulence. In addition, the tubes provide a throttling effect due to the fluid friction sufiicient substantially to eliminate undesirable pressure pulsations such as may be set up, for example, by the pump means used. The stock exiting from the multiple tubes 14, having undergone both the acceleration and the pressure drop described, enters the blending chamber 15 uniformly distributed in quantity and in a condition of fine scale turbulence and uniform dispersion entirely across the width of the paper machine inlet.

The plurality of generally parallel upwardly directed stock streams from the risers 14 enter a blending chamber 15, which illustratively is defined by wall portions 23a and 23]] forming an outwardly flared mouth portion and a roof portion 230 providing an impingement surface. In this chamber the stock undergoes a change of direction of at least 90. This insures that the velocities established in the tubes 14 will not persist in localized streams into the inlet, but that both velocity energies and papermaking stock will be further blended and distributed to a desirably uniform equality across the width of the flow box. The blending chamber 15 has essentially the same width as the flow box 12, and has a cross sectional area and volume such that the average velocities are therein reduced by a factor of approximately or more.

The reacceleration throat 16 is defined by a continuation or extension of the wall portion 23c of the blending chamber 15 and the upper end of the wall portion 23b of this same chamber. The throat 16 receives the reduced velocity stock flow from the blending chamber 15, and by providing a restriction in the flow path, increases the stock flow velocity markedly, and preferably to about one-half the velocity imparted to the stock flow by the risers 14, In this connection, the wall portion 23c is formed at one end with an upwardly turned flange 23d connecting with wall of the distributor assembly 10, and formed in the wall 24 is one or more vertically extending slots 24a receiving bolt means 25 providing a vertical adjustment for the wall portion 230 to thereby vary the cross-sectional area of the re-acceleration throat 16, whereby the stock flow velocity therethrough may be changed for particular conditions.

The reacceleration throat 16, like the blending chamber 1.5, has generaily the same width as the fiow box 12, and from the throat or restriction 16 the increased velocity stock flows in an upwardly inclined direction to the generally vertical conduit 17, which provides a plenum entry to the head box 12 and effects a deceleration of the stock flow prior to its movement through the bottom opening 22 in said head box. The rate of deceleration may advantageously be controlled by slightly increasing the wall to wall dimension as shown in FIGURE 1. Here also a change in the direction of how is preferably not less than The deceleration conduit 17 also has a width essentially the same as that of the flow box 12 and is disposed generally upright to provide a substantially right angle turn to the stock flow from the reacceleration throat 16. The vertical conduit 17 may be seen to have a relatively large cross-sectional area, and the velocity reduction in this conduit is preferably of the same order effected by the blending chamber 15, although of course this can be varied to suit the practical conditions encountered. Generally speaking, the stock flow velocity in the blending chamber 15 and deceleration conduit 17 is about the same, and the stock flow velocities in the risers 14 and reacceleration throat 16 are related by a ratio of approximately two to one.

As an illustration of the velocity changes effected throughout the system to obtain uniformity and homogeneity in the stock composition and distribution thereof, the following figures are given. Assuming an operating speed for the paper machine of about 1000 ft./min. or 16 ft./sec. and an effective slice opening S of 1", and neglecting effects of the stock characteristics such as consistency and freeness and the like, papermaking considerations require that the flow velocity through the slice opening be approximately equal to the paper machine or Fourdrinier wire speed. With a stock level in the headbox L of approximately 16 (approximately equal to the diameter of roll 21b) the average flow velocity in the headbox Will be about 1 ft./sec. The cross sectional area of the inlet plenum and decelerating conduit 17 is so sized as to yield an average velocity of from 1 to 3 ft./sec. The plenum 17 is supplied through the acceleration throat 16 which is so sized as to employ a flow velocity of approximately 9 ft./sec. This acceleration throat is in turn fed from the blending chamber 15 in which an average velocity will again be on the order of l to 4 ft./sec. The stock is introduced into the blending chamber 15 from the multiple tube risers 14 in Which the velocity under the conditions of the example would be approximately 18 ft./sec. As hereinbefore explained, it is desirable that the stock undergo a change in direction of at least 90. In the header 13, depending upon the maximum design speed of the particular machine, the velocities would be between 9 and 18 ft./sec. It may now be seen that the present device provides for successive acceleration and deceleration, and a desirable degree of friction losses thereby damping undesirable pulsations in the stock flow delivery and for uniformly dispersed and directed distribution over the width of the papermaking machine flow box. With this distributor the stock enters the flow box 12 in the live condition considered desirable by papermakers, but With a complete absence of the boiling and rolling irregularities which etfect undesirable irregularities in the paper being produced. The numeric values given in the example will be understood as applying only to a particular r set of conditions. The distributor apparatus has been found to be of value throughout speed ranges of at least 3 to 1 and velocities in the multiple tube risers may be as high as 27 or 30 ft./sec.

Particular applications may render it preferable to recirculate the stock, and a system suitable for this purpose is illustrated in FIGURE 4. As shown therein stock draining from the forming wire into the wire pit 30 may be directed through a conduit 31 wherein it is combined with fresh stock from a supply source '32 and forced under action of a fan pump or the like 33 to a centrifugal cleaner 34 of known construction controllable by a maual valve 35. The stock may proceed through a manual valve 36 to the delivery end 13a of the header 13, and a portion of the stock removed from the discharge end 1312 and recirculated through the line 37 back to the pump 33. The volume of stock to be recirculated may be controlled in accordance with the pressure drop from the delivery to the discharge ends of the header 18,

and pressure information from these ends may be obtained by

manometers

38 and 39 feeding this information to a suitable control device 40 operating an automatic valve 41 the flow range of which is controlled by a manual valve 42.

It is desirable that the static pressure difference between the delivery end 13a and discharge end 13b of the header 13 be close to zero, and the automatic recirculating valve 41 may be set to accomplish this condition. The Valve '35 maintains a constant flow rate through the centrifugal cleaner 34, and the adjustment of the valve 35 is correlated with the adjustment of the flow stream valve 36 to accomplish the desired result. As is apparent from FIGURE 4, closing the flow stream valve 36 will result in the stock supply being continuously recirculated through the centrifugal cleaner 34. While a recirculation system is shown and has been described,

\ efficient operation of the stock distribution apparatus of this invention does not depend upon a recirculation system, and in many installations the described system would not be employed.

It is to be appreciated that many variations may be effected in the method and apparatus of this invention, and as an example, is not required that the risers or tubes 14 be essentially straight as shown, since these tubes can well be curved as long as the plane of curvature of each tube lies in a plane parallel to the center line of the paper machine. This and other variations and modifications can be effected without departing from the novel concepts of the present invention.

We claim as our invention:

1. In a paper machine having a stock inlet box and a stock delivery conduit, a stock distributor assembly connecting at one end with the conduit and at the oppo site end with the box to eliminate velocity profile irregularities in the stock pond in said box, the stock distributor assembly comprising a header connecting with the conduit and extending the full width of the box, a plurality of tubes extending upwardly from the header in planes parallel With the machine centerline, the diameters of the tubes being related to the width of the stock pond and to the tube lengths to eliminate essentially all velocity components in the stock flow transverse to the machine direction, means defining a blending chamber connecting with the tubes and extending the full width of the inlet box to reduce the stock flow velocity, means providing a reacceleration throat having a width essentially the same as the box and increasing the velocity of the stock received from the belnding chamber, and a deceleration conduit connecting with the reacceleration throat and with the inlet box to reduce the stock flow velocity to that desired for delivery ino said inlet box, means feeding stock from said stock delivery conduit into one end of said header, recirculating means Withdrawing a portion of stock from the opposite end of said header and returning stock to said one end of said header, said header having a cross sectional area diminishing in the direction of stock flow therethrough to provide, in combination with the recirculating means, a substantially uniform output to each of said tubes, the improvement of having the tubes relatively slender with the length-to-diameter ratio of said tubes being substantially from 7 to 1 to 25 to 1.

2. In a paper machine having a stock inlet box and a stock delivery conduit, a stock distributor assembly connecting at one end with the conduit and at the opposite end with the box to eliminate velocity profile irregularities in the stock pond in said box, the stock distributor assembly comprising a header connecting with the conduit and extending the full width of the box, a plurality of tubes extending upwardly from the header parallel with the machine centerline, the diameters of the tubes being related to the Width of the stock pond and to the tube lengths to eliminate essentially all velocity components in the stock flow transverse to the machine direction, a blending chamber formed with a generally V-shaped base portion connecting with the tubes and an essentially flat roof portion disposed substantially normal to the centerline of the tubes and providing an impingement surface for the stock flow from the tubes to turn the same through at least a right angle and reduce the velocity thereof, means providing a reacceleration throat having a width essentially the same as the box and increasing the velocity of the stock received from the blending chamber, and a deceleration conduit connecting with the reacceleratiou throat and with the inlet box to reduce the stock flow velocity to that desired for delivery into the box, means feeding stock from said stock delivery conduit into one end of said header, recirculating means withdrawing a portion of stock from the opposite end of said header and returning stock to said one end of said header, said header having a cross sectional area diminishing in the direction of stock flow therethrough to provide, in combination with the recirculating means, a substantially uniform output to each of said tubes, the improvement of having the tubes relatively slender with the length-todiameter ratio of said tubes being substantially from 7 to 1 to 25 to 1.

3. In a paper machine having a stock inlet box and a stock delivery conduit, a stock distributor assembly connecting at one end with the conduit and at the opposite end with the box to eliminate velocity profile irregularities in the stock pond in said box, the stock distributor assembly comprising a header connecting with the conduit and extending the full width of the box, a plurality of tubes extending upwardly from the header in planes generally parallel with the machine centerline, the diameters of the tubes being related to the width of the stock pond and to the tube lengths to eliminate essentially all velocity components in the stock flow not lying in planes parallel with the machine direction, means defining a blending chamber connecting with the tubes and extending the full width of the inlet box to reduce the stock flow velocity, means providing a reacceleration throat having a width essentially the same as the box and increasing the velocity of the stock received from the blending chamber, and a deceleration conduit connecting with the reacceleration throat and with the inlet box to reduce the stock flow velocity to that desired in the box, the tubes, blending chamber, reacceleration throat and deceleration conduit being sized to provide a stock flow rate in the tubes and throat which is substantially the same, and a stock flow rate in the blending chamber and deceleration conduit which is about the same, means feeding stock from said stock delivery conduit into one end of said header, recirculating means withdrawing a portion of stock from the opposite end of said header and returning stock to said one end of said header, said header having a cross sectional area diminishing in the direction of stock flow therethrough to provide, in combination with the recirculating means, a substantially uniform output to each of said tubes, the improvement of having the tubes relatively slender with the length-to-diameter ratio of said tubes being substantially from 7 to 1 to 25 to 1, and means in control of said recirculation means for maintaining a substantially uniform static pressure across said header.

4. In a paper machine having a stock inlet box and a stock delivery conduit, a stock distributor assembly connecting at one end with the conduit and at the opposite end with the box to eliminate velocity profile irregularities in the stock pond in said box, the stock distributor assembly comprising a header extending the full width of the box and being of tapering cross section sized to provide a substantially uniform output entirely therealong, a plurality of closely laterally spaced tubes extending upwardly and rearwardly from the header and receiving substantially parallel stock streams and accelerating the velocity thereof to that required in the inlet box while eliminating from said streams any velocity components transverse to the machine direction, a conduit extending along the width of the inlet box and shaped to first define a blending chamber receiving the high velocity stock streams and to provide a reacceleration throat downstream from said said blending chamber, the conduit having a relatively flat wall portion providing a roof disposed normal to the centerline of the tubes and against which said stock streams impinge to be turned toward the reacceleration throat, means for adjusting said wall portion to vary the opening of said throat to adjust the stock flow velocity to the flow rate required in the inlet box, and a deceleration conduit connecting with the reacceleration throat and with the inlet box to reduce the stock flow velocity to that desired for delivery into the box, means feeding stock from said stock delivery conduit into one end of said header, recirculating means withdrawing a portion of stock from the opposite end of said header and returning stock to said one end of said header to provide, in combination with the tapering cross section of the header, a substantially uniform output to each of said tubes, the improvement of having the tubes relatively slender with the length-to-diameter ratio of said tubes being substantially from 7 to 1 to 25 to 1.

References Cited in the file of this patent UNITED STATES PATENTS 2,869,436 Stewart Jan. 20, 1959 2,894,581 Goumeniouk July 14, 1959 2,911,041 Beachler Nov. 3, 1959 2,970,938 Erbach Feb. 7, 1961