US2960162A - Machine for forming continuous strips of fibrous materials - Google Patents

Description

Nov. 15, 1960 A. D. SIMPSON MACHINE FOR FORMING CONTINUOUS STRIPS OF FIBROUS MATERIALS Filed Aug. 8, 1957 3 Sheets-Sheet 1 IIEL. d n f 1 INVENTOR. All/an B 52;

ATTORNEY Nov. 15, 1960 A. D. SIMPSON 2,950,152

MACHINE FOR FORMING commuous STRIPS OF FIBROUS MATERIALS 3 Sheets-Sheet 2 Filed Aug. 8, 1957 INVENTOR.

n w w@ .m .w flu A M M Nov. 15, 1960 A. D. SIMPSON 2,950,162

MACHINE FOR FORMING CONTINUOUS STRIPS OF FIBROUS MATERIALS Filed Aug. 8, 1957 3 Sheets-Sheet 3 ATTORNEY United States Patent C) MACHINE FOR FORMING CONTINUOUS STRIPS OF FIBROUS MATERIALS Alvan Doswell Simpson, Plainfield, N.J., assignor to The Forming Machine Company of America, Inc., a corporation of Delaware Filed Aug. 8, 1957, Ser. No. 677,103

Claims. (Cl. 162-301) This invention relates in general to machines for forming continuous strips of compositions of matter from wet mixes comprising solids including fibers and liquid, wherein solids from the mix in a tank are deposited on a screen while the liquid from the mix passes through the screen into a suitable drain, and the screen and the deposited layer thereon are continuously moved out of the tank. More particularly, the invention contemplates a machine of the general type described and claimed in my Patent No. 2,737,858 dated March 13, 1956, which includes a tank having an opening at its lower end, a screen or other foraminous wall extending approximately horizontally across said opening with the upper side thereof in contact with and supporting the mix in the tank, the mix being forced against the foraminous wall under pressure to cause liquid to flow from the mix through said wall and deposit solid particles in a layer on the first mentioned side of said wall, means for moving said foraminous wall across said opening from one side to the opposite side thereof and sealing means between the edges of said opening and said foraminous wall to prevent passage of liquid from the tank except through said opening, said sealing means including a roll outside the tank in rollable contact with the deposited layer on said foraminous wall.

, During the operation of a machine of this general type, the foraminous wall or screen must move rapidly across the opening and the turbulence or local currents caused by the relative movement of the deposited layer and the wet mix in contact with the layer adjacent the exit sealing roll, that is, the roll at the end of the opening from which the deposited layer emerges will cause variations in the thickness and uniformity of the deposited layer; and a prime object of the invention is to provide novel and improved means to overcome such erosion and to ensure uniformity in thickness and composition of the deposited layer as it emerges from the tank.

Another object is to provide such a machine which shall include a secondary foraminous wall or screen movable at the same linear speed as the main foraminous wall or screen upon which the layer is deposited so that said deposited layer shall be protected between said main and auxiliary screens in the tank prior to the passage of the layer beneath said sealing roll, whereby said secondary or auxiliary protective screen shall prevent or reduce the friction currents between the deposited layer and the mix just before the layer reaches the exit sealing roll, and reduce or prevent friction currents between the deposited layer and the mix above the layer and thus eliminate any turbulence in the wet mix that might interfere with the uniformity of thickness and composition of the deposited layer.

- Other objects, advantages and results of the invention will be'brought out by the following description in conjunction with the accompanying drawings in Which- Figure l is a fragmentary side elevational view of a machine similar to Figure 1 of my said Patent No.

p we

2,737,858, embodying the invention, with portions broken away and shown in section;

Figure 2. is an enlarged transverse vertical sectional view approximately on the plane of the line 2-2 of Figure 1 with portions omitted;

Figure 3 is a vertical longitudinal sectional .view approximately on the plane of the line 3-.3 of Figure 2;

Figure 4 is a fragmentary transverse vertical sectional view approximately on the plane of the line 4-4 of Figure 3; Figure 5 is a similar view approximately on the plane of the line 5-5 of Figure 3;

Figure 6 is a fragmentary enlarged sectional view showing the exit sealing roll and the main and auxiliary screens as illustrated in Figure 3;

Figure 7 is a fragmentary sectional view of the exit side of a wet mix tank showing a modification of the invention;

Figure 8 is a fragmentary transverse vertical sectional view approximately on the plane of the line 88 of Figure 7;

Figure 9 is a view similar to Figure 7 showing another modification of the invention; and

Figure 10 is a fragmentary transverse vertical sectional view approximately on the plane of the line 10-10 of Figure 9.

For the purpose of illustrating the principles of the invention, I have shown it in connection with the wet mix tank and the conveyor for the foraminous wall or screen that are illustrated my Patent No. 2,737,858, but it should be understood that the invention may be utilized in connection with other types of machines within the spirit and scope of the invention. The machine is shownas comprising a main frame A at each end of which is journaled a shaft B, only one end of the frame and one shaft being here shown. On each shaft is a sprocket 1 having radial arms 2 that have notches in their outer ends to engage combined pivot and tie rods 3 each of which pivotally connects together two sections 4 of an endless conveyor which carries the foraminous, perforate or reticulate wall or screen 5 as will be hereinafter described. The sections 4 are of such width that the longitudinal edges of adjacent sections which extend transversely of the conveyor abut each other so as to form a substantially continuous horizontal upper surface in the upper reach of the conveyor. The sections 4 extend transversely horizontally of the frame and have shoes 6 at their ends to slidab-ly'engage horizontal rails or tracks 7 for supporting the upper reach of the conveyor in a horizontal plane. The sections in the lower reach of the conveyor are similarly supported by guide rails 8. The conveyor may be driven from any suitable source of power, for example from a belt and pulley connection 9.

Mounted on the frame above the upper horizontal reach of the conveyor as by bracket arms 10 is a tank C for a mixture 11 of solids, such as Wood pulp, asbestos fiber, cement or granulated synthetic resin suspended in a liquid, the lower end of the tank opening onto the top surface of the upper reach of the conveyor and being sealed against escape of liquid except through the conveyor sections 4 that have perforate or foraminous portions intermediate their ends and extending to the longitudinal edges of the sections as best shown in Figures 1 and 2 to form the foraminous wall 5 on the upper reach of the conveyor. As shown, the foraminous portions rest on the-edges of supporting slats 14 that are in turn supported by bars 15 which are carried by the main beams 16 that extend transversely of the sections and have their ends-connected to side bars 17 that are provided with perforate ears 18 through which the pivotand, tie rods 3 extend, all as clearly shown and described in my y 3 said patent. A suitable agitator 19 for the liquid like that of said patent, may be provided if desired.

Also, any suitable means such as described in said patent may be utilized for preventing leakage of the liquid between the walls of the tank and the upper reach of the conveyor, but as shown, such means comprises an upstanding projection on and extending along each longitudinal margin of the foraminous wall. Said upstanding projection includes blocks 24 on the conveyor sections, which when the sections are in the upper reach of the conveyor, abut each other and form a smooth upper bearing surface for a resilient sealing element which may be of the same general construction as the sealing strip of my Patent No. 2,723,599. The blocks also form vertical shoulders 26 facing into the tank and abutted with a fluid tight contact by the ends of rollers 27 and 27a which may be mounted on the frame and tank in any suitable manner, which for the purpose of illustration is shown as comprising guide frames 28 that are mounted in brackets 29 and are forced toward the upper reach of the conveyor by the fluid pressure motors 30. The lower edges of the end walls of the tank are spaced from the foraminous wall to provide passages 31 for the mix; and while these passages may be sealed in any suitable manner, there is shown a resilient strip 25 mounted in a channel shaped holder D that is secured to the walls of the tank with one part of the strip engaging the blocks 24 and other portions engaging the peripheries of the rolls 27 and 27a. The spaces between the holder D and the tank may be closed by plates 35. Obviously the joints between the abutting ends of the blocks 24 will be preferably sealed, for example as shown in my patent.

, The mixture 11 may be forced into the tank through a supply pipe 36, and in accordance with the invention either gas at high pressure, substantially above atmospheric pressure, for example ten to one hundred pounds per square inch, is admitted into the space or chamber of the tank above the surface of the mix through a pipe 37, or the tank may be left open to the atmosphere and constructed of sufiicient height to provide a substantial static head on the mix.

With this construction the gas pressure forces the liquid through the foraminous wall and causes a deposit of the solid particles from the mix in the form of a layer B on the conveyor, the liquid being forced from the mix through said foraminous wall the undersides of which are exposed to the atmosphere. The liquid that flows through the foraminous wall may be disposed of in any suitable manner, for example as by a catchpan from which the liquid may be conducted by a trough or pipe to any suitable point.

In operation of the machine it will be observed that deposition of the layer will start adjacent the inlet sealing roll 27, that is, the roll at the side of the tank at which the foraminous wall enters the opening at the bottom of the tank, and the layer will gradually increase in thickness as it approaches the exit sealing roll 27a.

The foraminous wall 5 and the deposited layer must move rapidly and turbulence or local currents are caused by the relative movement of the layer and the wet mix which, in the absence of some means to prevent it, will have a tendency to erode or wash away portions of the layer and vary the uniformity of the mix and thereby cause variations in thickness and composition of the layer.

'The invention provides means to prevent such action. This means isshown as comprising a secondary or auxiliary screen in the tank having a portion adjacent the exit roll between which and the main foraminous wall or screen 5 is protected the deposited layer before the layer emerges from the tank.

Referring particularly to Figures 1 to 6 inclusive, the reference character 40 designates a flexible foraminous perforate or reticulate endless belt or wire mesh screen which. passes around the sealing rolls 27 and 27a and around idler rollers 41, 42, 43, 44, 45 and 46. The roller 41 is mounted inside the tank in suitable hearings on the side walls of the tank and a portion of the belt screen extends from beneath the entrance sealing roller 27 to the idler roller 41 and thence vertically upwardly to a point 5 above the level of the wet mix 11 and around the idler roller 42 from where the belt extends horizontally in the tank and around the idler roller 43, thence vertically downwardly and around the idler roller 44. A portion of the belt extends from the roller 44 beneath the exit roll 27a, thence upwardly around the idler 45, then horizontally above the top of the tank and around the idler roller 46 back to the entrance roll 27. The portion 40a of the belt between the idler 44 and the exit roll 27a is inclined tangentially from the underside of said roll upwardly and inwardly of the tank in spaced opposite relation to the main foraminous wall or screen 5, as best shown in Figure 6. The distance between the inner end of said portion 40a of the secondary or auxiliary screen and the main screen 5 is of the order of probably twice or more the thickness of the deposited layer depending on the type of layer and the mix being used. While the machine is operating, the portion 40a of the auxiliary or protective screen gradually approaches the top surface of the deposited layer and touches it just before the newly deposited layer E reaches the exit roll 27a, as best shown in Figures 3 and 6. The mix in contact with the layer as it approaches the portion 40a of the auxiliary or protective screen will pass into the wedge-shaped space between the screen and the layer because both the screen and the layer are travelling at the same speed, and then the mix will move upwardly from said space through the screen portion 40a with practically no resistance to its movement through the belt screen, while some of the water in said mix will pass through the deposited layer. As the deposited layer emerges from the tank beneath the exit roll, the secondary or auxiliary screen moves upwardly away from the layer. Preferably the secondary or auxiliary screen 40 will be moved lengthwise at the same linear speed as the main screen 5 and deposited layer, and if desired, the exit roll 27a may have a belt and pulley connection 47 with a suitable source of power, for

example the shaft B.

From the foregoing it will be seen that the portion 40a of the secondary or auxiliary secreen will protect the deposited layer from any disturbance incident to the relative movement of the deposited layer and the wet mix as the layer approaches the exit of the tank, so that uniformity of thickness and composition of the layer as it emerges from beneath the exit roll, is ensured.

It is essential that the portion 40a of the auxiliary screen between the idler 44 and the exit roll, be clean with its perforations open so that the liquid in the mix between the two screens can pass through the auxiliary screen and thereby permit the auxiliary screen to approach and then contact the deposited layer. Accordfrom the exit roll to the entrance roll. As shown, a spray pipe 48 may be mounted above the screen for directing jets of cleaning liquid such as water through the screen and thereby force any solid particles out of the openings or interstices of the screen. The waste water and solid matter may be collected in a catchpan 49 or other suitable means and conducted to a waste or drain pipe.

A modification of the invention is shown in Figures 7 and 8 which is especially suitable where only small pressures on the mix are required for depositing the layer of solids so that only a liquid gravity seal is necessary at the point of entrance of the screen to the tank. In this form of the machine, the mix tank F has a vertical elongate standpipe 49 extending from a point inside the tank and inwardly of the exit roll 27!) to a point substantially above the tank. The standpipe has water therein at a height to provide a static head pressure sufficient to overcome the pressure in the tank above the ingly, it may be desirable to wash the screen as it passes wet mix. The auxiliary or secondary screen 50 is in the form or" an endless belt having one reach extending through said standpipe and passing around an idler roller 44a, spaced inwardly from the exit roll 27b, and around an idler roller 46a disposed above the upper end of the standpipe, from which the secondary screen passes around another idler roller 45a and to the exit roll. The portion 50a of the secondary or auxiliary screen corresponds to the portion 40a of the secondary screen 40 and cooperates with the main screen a and the exit roll 27b in the same manner. A spray pipe 48a and catchpan 49a may be provided for washing the secondary screen.

A further modification is shown in Figures 9 and where the endless secondary or auxiliary screen 51 passes around an idler roller 44b disposed inside the tank G and inwardly of the exit roll 27c, and around two idler rollers 45b and 46b that are disposed outside of the tank. The exit roll 27c is journaled in a guide frame 28a and an auxiliary sealing roll is also journaled in said 'frame with its trunnions 53 slidable in slots 54 in the frame so that the roll may be yieldingly pressed by springs 55 toward the roll 270 to provide a sealing contact between the two rolls and the auxiliary screen 51. The sealing means D that is in general similar to the sealing means D has a portion D" engaging the periphery of the auxiliary sealing roll 52 instead of engaging the periphery of the exit roll 27c and the seal ing means D will have portion engaging the end surfaces of both the rolls 27c and 52. The portion 51a of the screen between the idler roller 44!) and thevexit roll 270 is related to the main screen 512 and to the deposited layer to ensure uniformity of thickness and composition of the deposited layer in the same manner as the portions 40a and 50a of the screens 40 and 50.

A spray pipe 48b and catchpan 491) may be provided for washing the auxiliary screen 51 outside the tank.

It will be understood that the sealing means D as shown in Figures l-6 inclusive may also be used in the form of the invention shown in Figures 7 and 8. It will be further apparent that the auxiliary screens 50 and 51 may be driven in the same manner as the screen 40.

Other arrangements of the foraminous auxiliary, secondary or protective wall or screen and use of the invention with other types of machines, will occur to those skilled in the art as Within the spirit and scope of the invention.

What I claim is:

1. A machine for forming a continuous strip of material from a wet mix of solids suspended in liquid, comprising a tank having an opening in its lower end with its edges in a common approximately flat plane, an approximately flat elongate foraminous main wall extending across said opening with the upper side thereof to contact with and support said mix in the tank with a pressure on the mix and with the other side of said foraminous wall exposed to atmospheric pressure, means for moving said main wall across said opening from one side edge to the opposite side edge thereof to cause deposit of a layer of solids on said foraminous main wall, means preventing leakage of liquid between the walls of the tank and said foraminous main wall including a roll extending across said opening along the secondmentioned edge thereof and having a smooth peripheral surface for fluid-tight rolling contact with said layer of solids, a flexible endless auxiliary foraminous wall runing around said roll through said mix from the inside to the outside of the tank with a straight portion extending from and tangentially to said roll a short distance inwardly of the tank in spaced opposed relation to said main wall with its perforations open and unobstructed and providing for positioning of a zone of said deposited layer between said main wall and said straight portion of the auxiliary wall and for free movement of the mix from the space between said zone of said layer and said straight portion of the auxiliary wall through the perforations of said straight portion, and means mounting said auxiliary wall for movement with and in the same direction as said main wall as said main wall with the deposited layer approaches and passes said roll outwardly of the tank, thereby to protect said zone of said layer from erosion, alteration or disturbance due to turbulence in the mix adjacent said roll.

2. A machine as defined in claim 1 with the addition of a vertical standpipe extending upwardly in said tank adjacent the second-mentioned edge of said opening and through which runs a portion of said endless auxiliary foraminous wall.

3. A machine as defined in claim 1 with the addition of an auxiliary roll in parallel juxtaposed relation to the first roll mounted along said second-mentioned edge of said opening and means for normally yieldingly urging said auxiliary roll toward the first-mentioned 'roll, and wherein said endless foraminous wall runs outwardly from the tank between said rolls.

4. A machine as defined in claim 1 wherein said straight portion of the auxiliary wall is inclined at a small angle to said main wall upwardly from the line of contact of said straight portion with said roll.

5. A machine as defined in claim 1 wherein said straight portion of the auxiliary wall is inclined at a small angle to said main wall upwardly from the line of contact of said straight portion with said roll, and with the addition of means for moving said auxiliary wall synchronously with said main wall.

References Cited in the file of this patent UNITED STATES PATENTS 682,544 Graham Sept. 10, 1901 1,335,909 Munroe Apr. 6, 1920 1,500,208 Shaw July 8, 1924 1,650,100 Stephansen Nov. 22, 1927 2,161,653 Ellis June 6, 1939 2,173,391 Ellis Sept. 19, 1939 2,208,511 Ellis July 16, 1940 2,666,369 Niks Jan. 19, 1954 2,717,538 Alexander Sept. 13, 1955 2,737,858 Simpson Mar. 13, 1956 2,761,365 Bridgewater Sept. 4, 1956 FOREIGN PATENTS 6,948 Great Britain Mar. 19, 1914

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