US2700188A - Fiber web forming machine - Google Patents

Description

Jan, 25, 1955 F. M. BUREISH ET AL 2,700,188

FIBER WEB FORMING MACHINE Filed May 11, 1948 5 Sheets-Sheet l E? JNVENTQR.

M mmmm M mime-5W H mwm mam Jan, 5, 1955 Filed May 11, @948 F. M. BURESH ET AL FIBER WEB FORMING MACHINE 5 Sheets-Sheet 2 FIBER WEB FORMING MACHINE 5 Sheets-Sheet 3 Filed May 11, 1948 k g M 1 Ha. 5

"""" INVENTOR.

FRfi/VG/S M. BURESH HOWARW H! LAIViQDO/V Jan, 25, 1955 F. M. BURESH ET AL 2,700,188

FIBER WEB FORMING MACHINE Filed May ll, 194.8 5 Sheets-Sheet 4 4/ JNVENTOR.

FfiANG/S M. EURES'H BY HUWARD H; LANGUON Janu 25, 1955 BURESH ET AL 2,700,188

FIBER WEB FORMING MACHINE Filed May 11, 1948 5 Sheets-Sheet 5 F 7 I N V EN TOR.

I FRANCIS M BURE'SH BY HOWARD H. LANGDO/V ATTORNEY United States Patent FIBER WEB FORMING MACHINE Francis M. Buresh, hiandford, Mass, and Howard H. Langdon, Rochester, N. Y., said Langdon assignor, by mcsne assignments, to Curiator Corporation, Rochester, N. Y., a corporation of New York Appiication May 11, 1948, Serial No. 26,256

4 Claims. (@l. l9--66) The present invention relates to a machine for forming random textile fiber webs. In a more specific aspect, the invention constitutes an improvement over the random web forming machine of the Buresh application Serial No. 666,445, filed May 1, 1946, now Patent No. 2,451,915, granted October 19, 1948.

In the machine of the Buresh patent above mentioned the work material is fed into a liclterin, which is rotating at high speed, in such way that single fibers are combed and drawn out of the material by the teeth of the rotating lickerin; the fibers are doffed from the lickerin by suction of a high-velocity air stream and by the centrifugal force resulting from the high speed of rotation of the lickerin; they are then carried by the air stream onto a rotary condenser, which is simply a screen slowly rotating about an axis extending at right angles to the direction of flow of the air stream. The fibers are thus randomly deposited on the condenser; and thus a fiber web is built up on the condenser which has equal strength in all directions in the plane of the web. The fibers are pressed together to compact the web; and the compacted web is delivered onto a conveyer or otherwise discharged from the machine.

One of the great difficulties in manufacturing a random web is to obtain uniform thickness of the web across its whole width. Even in a machine built according to the Buresh patent above mentioned Webs will sometimes be formed that are thin at their edges. Moreover, the webs will sometimes have ropes of fibers formed in them. These defects seem to result from static electricity which causes the fibers to attract one another and to bunch. Static charges are probably generated in the air stream by the friction of turbulence and especially by friction between the air stream and fibers during the pull-out and doffing action at the lickerin or just following the doifing action where there may be acceleration or deceleration of the fibers related to the air stream. These static charges are carried by the fibers, dust particles, etc. downstream to the condenser, and are dissipated there by contact with the metallic condenser screen, but they are not dissipated until the fibers are deposited on the screen and the fibers especially on a dry day, are apt to be deposited on the screen unevenly and in bunches due to these static charges.

Aside from intermittent difiiculties with static, machines constructed according to the Buresh patent are quite satisfactory in operation when employed singly or in small numbers. The number of such machines, which can be installed in a single work-room, is, however, limited. The Buresh machine takes air from the room in which the machine is installed and discharges that air back into the room. If a large number of machines are drawing air from the Work-room and discharging air into the work-room, a great turbulence of air will be created. Of course, all of the discharge ducts of the several machines might be connected together to a single discharge duct. but the problem of disposing of the air still remains. l f the air is discharged outdoors this means a great loss of heated air in winter time with a consequent increase in the consumption of the fuel required for heating the work-room. In any case, the problem of eliminating static is multipled if constantly new air is being used in the machine.

A primary object of the present invention is to provide a machine for forming random fiber webs which will produce a web of uniform thickness from edge to edge.

Another object of the invention is to provide a machine for forming random fiber webs according to the method of the Buresh patent above mentioned in which the problem of air disposition is eliminated.

Another object of the invention is to provide a practical control for static in a machine of the class described.

Another object of the invention is to provide a machine of the character described in which the static charges are more or less neutralized as they are formed, thereby obviating possible static interference with formation of a uniform web.

A further object of the invention is to provide a machine of the character described in which control of static is combined with a closed air-circulating system so as to minimize both the problem of static control and of air circulation.

Stilt another object of the invention is to provide a machine of the character described which will be selfcontained and compact, and which may operate as a unit or be combined with other machines in any number in a work-room of any size.

A further object of the invention is to provide a ma chine of the character described which will be substantially automatic in operation, and which will require a minimum of attention during operation. To this end, it is a further purpose of the invention to provide a machine having a hopper feed mechanism for automatically feeding the work material into the lickerin roll, so that the operator may dump a batch of the work material into the hopper and the machine will then take care of itself for a relatively long period.

Still another object of the invention is to provide a hopper feed mechanism for a machine of the character described which will feed the work material to the lickerin in a lap of uniform thickness, thereby further aiding in formation of a random web of uniform thickness.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims.

In the drawings:

Fig. 1 is a vertical sectional View taken longitudinally through a machine built according to one embodiment of this invention;

Fig. 2 is a part-plan, part horizontal sectional view of the machine;

Fig. 3 is a vertical sectional view on a considerably enlarged scale, showing the condenser and its mounting, the view being taken on the line 3-3 of Pig. 1;

Fig. 4 is a view from the right hand end of the machine as viewed in Fig. 1, partly in elevation and with parts broken away;

Fig. 5 is an enlarged vertical sectional per and hopper feed mechanism;

Fig. 6 is an end elevation of the hopper with parts broken away;

Fig. 7 is a diagrammatic view illustrating the operation of the humidifying apparatus for controlling static;

Fig. 8 is a fragmentary view illustrating a difierent embodiment of the invention in which steam is employed to humidify the air stream and control the static;

Fig. 9 is a similar fragmentary view showing use of an eleftrical neutralizer as an alternate form of static contro Fig. 10 is a similar fragmentary view showing use of a radio-active type of static eliminator; and

Fig. 11 is a fragmentary view showing how stock material in the form of a roll or picker lap may be fed into the machine.

Referring now to the drawings by numerals of reference, 20 indicates the base or frame of the machine. This may be made of fabricated steel with suitable reinforcements and is generally rectangular in shape. Secured to the upper face of the frame 26 is a lap bed or feed plate 21 which is a flat horizontally disposed plate having a smooth upper surface. Mounted on the frame 20 to lie above this plate is a hopper denoted generally at 22. This may be supported from the frame by brackets or uprights 34. The hopper has an opening 23 in its upper side into which stock material, such as reclaimed tire cord, napper flocks, etc., may be dumped loose or in chunks from bags or be taken in directly from the plant conveyer system.

view of the hop- The hopper has a floor comprising a downwardly in clined plate 24 and a plurality of freely rotatable rollers 25 which are journaled in the side walls of the hopper parallel to one another and which extend in the same generally downwardly inclined direction as the plate 24 and constitute in effect an extension of that plate. The rollers are slightly spaced from one another to allow passage of air therebetween so that they in effect constitute a perforated flooring.

Mounted within a chamber 27 formed in the hopper by a partition wall 28 and the right hand side wall 29 of .the hopper are a pair of rolls 30 and 30' over which runs an endless flexible screen or foraminous belt 31. The rolls are so positioned that the underside of the belt is inclined to the plane of the rolls 25 and converges toward the rolls toward the right. The upper end of the chamber 27 is closed and it has a blower 32 mounted therein which sucks air up through the spaces between the rolls and through the perforations in the belt 31.

The rolls 30 and 30' are journaled at their ends in the side walls of the hopper. One of the rolls 30 or 30' may be the driver and the other an idler. The driver may be driven from the same motor (not shown) as drives the blower or in any other suitable manner. As the screen 31 revolves, the work material in the hopper 23 is caught between the screen and the rollers 25 and fed down onto the bed plate 21. The rollers 25 freely rotate and revolve simply by the friction of the material caught between them and the screen 31. The left hand side of the hopper below floor plate 24 may be open or have air vents therein. Hence the blower 32 will suck air up through the spaces between the rollers 25, and the interstices of the conveyor screen 31. As the screen 31 moves forwardly, then, urging the material downwardly over the feed rolls 25, the air passing between the conveyor rolls and through the conveyor screen seeks the path of least resistance. Whenever there is more or less compacted material between the rolls and screen, air flow is restricted. If there is a void or a thin space any place in the material, however, there is a pressure drop at that spot; and the air tends to rush in from the surrounding area, and in doing so it moves the incoming material into the empty or thin space. This helps make the material being fed down onto the bed plate 21 of uniform thickness across the whole width of the feed area and supplies to the bed plate a continuous lap of material of uniform thickness for the desired width.

Mounted above the bed plate and very close thereto is a feed roller 40. 'This is suitably journaled at its opposite ends in bearings, of which one is shown at 42 in Fig. 2, which are adjustable to regulate the feed pressure. The mounting may be similar to that of the feed roll of the machine of the Buresh patent referred to above.

The bed plate 21 is formed at its right hand end with a nose or riser portion 41. The upper side of the nose portion is curved in close conformity to the curvature of the adjacent part of the periphery of the feed roll 30, for the purpose of disposing the stock material to the action of the lickerin in such way that the teeth of the ggkerin will comb and draw out of the stock individual ers.

The lickerin 45 may be constructed like the lickerin of the Buresh machine. It is provided with a plurality of peripheral lickerin teeth 46 which may be similar to saw teeth, being reversely beveled with an outward pointed taper and a slight pitch inwardly at their lowermost edges. The lickerin may be journaled on the frame of the machine in a manner similar to the lickerin of the Buresh machine and may be driven from a motor 47 (Fig. 4) through a pulley 48, belt 49 and pulley 50, the last-named pulley being secured to the shaft of the lickerin.

The feed roll 40 is also positively driven and may be driven from the lickerin shaft or direct from motor 47.

As the lickerin revolves, its teeth pick fibers from the stock being fed to it by the feed roller and the teeth carry these fibers around into an air duct into which the lickerin extends at its bottom. A high velocity air stream circulates in this air duct through operation of a blower, as will be described hereinafter. Hence, the fibers are dotfed from the lickerin by the suction of this air stream and by the centrifugal force created by the high speed rotation of the lickerin itself. The air stream travels in a direction substantially tangential to the lickerin at a point approximately 90 from the point at which the fibers are picked up by the lickerin teeth.

The fibers carried in the air stream are delivered to a rotary condenser 57 which is made of wire mesh or of any suitable reticulated material. The wire mesh or reticulated material is cylindrical in shape and is secured by clamping plates 58 (Fig. 3) and screws 59 in lugs 60 of end plates 61 and 61, respectively. These end plates are welded to or integral with hubs 62 and 62, respectively, that are journaled by means of anti-friction bearings 63 on stub shafts 64 and 64, respectively. The stub shafts 64 and 64 are clamped by pillow blocks 65 and 65', respectively to the frame 20 so that they are held against rotation. The condenser is adapted to be driven from a motor (Fig. 4) through a suitable variable speed reducer, a sprocket 72, chain 73, and sprocket 74. Sprocket 74 is secured to a hub 75 by screws 76, and this hub is integral with or keyed to the hub 62.

Within the condenser 57 is a stationary continuation of air duct 55. This portion of air duct 55 is formed by upper and lower plates and 80', respectively, which are secured in side plates 81 and 81 (Fig. 3) that are mounted upon the stationary stub shafts 64 and 64, respectively. Reinforcing arcuate plates 82 and 82' (Figs. 1 and 3) are provided above and below the upper and lower plates 80 and 80 and may be welded thereto. These arcuate plates are mounted in arcuate grooves in the side plates 81 and 81.

The fibers deposited in random fashion on the condenser 57 by the high velocity air stream flowing through the condenser are pressed thereagainst by a pressure roller 85 which is journaled in spring members 86 that are fastened to the upper surface of the frame of the machine. The pressure roller is driven by frictional engagement with the web.

Adjacent the uppermost portion of the condenser 57 is an endless conveyor belt 90. This conveyor belt is trained about supporting rollers 91 and 91 that are suitably journaled in brackets 93 which are secured to the upper face of frame 20. The roller 91 is adapted to be driven at the same surface speed as the condenser. It may be driven direct from motor 70 or from the condenser. The random web formed on the condenser 57 is delivered onto the conveyor belt which serves to convey it to the discharge point of the machine. At the beginning of the operation, the operator of the machine may lift the leading edge of the web manually onto the conveyor belt 90 so that thereafter the web will feed onto the belt, or, if desired, a plate (not shown) may be mounted between the condenser 57 and the conveyor belt 90 to guide the web being formed. onto the belt.

The air system of the machine is a closed, recirculating system. Circulation is produced by a blower or fan (Fig. 4) which is driven by the motor 101 (Figs. 1 and 4-) through a pulley 102, belt 103, and pulley 104. The last-named pulley is secured to the shaft on which the fan is mounted. The fan is mounted within the housing 105. The inlet side of the fan connects with a vertical duct 106 that extends across the full width of the frame at one end thereof. This duct is formed between the right hand end wall of the frame and duct plate 107 (Fig. 1). The vertical duct 106 is rounded at its upper end and connects with a duct or passageway 108 which is aligned with the passageway through the condenser and constitutes a continuation thereof. Suitable seals are provided at the junctures of passageways 55 and 108 with condenser 57 to prevent leakage of air at these points. 'Likewise, suitable seals are provided internally of the condenser at the junctures of plates 80 and 80 therewith to prevent air-leakage.

The blower housing is connected at its pressure side with a duct 110 (Figs. 1 and 2) which is suitably supported within frame 20. The duct 110 connects at its left hand end with a vertical duct 112 which extends across the full width of the frame of the machine and which is formed between the left hand end wall of the machine and a duct plate 113. The duct 112 is curved at its upper end and joins the duct 55. The duct 55 extends across substantially the full internal width of frame 20 and at one side of the lickerin is formed between the upper wall of the frame and the plate 116. At the op posite side of the lickerin it is formed between plate .116 and an upper plate 117. The wall or floor 116 converges toward the lickerin 45 on the approach or pressure side of the lickerin and diverges from the wall or cover 117 on the suction side of the duct. The wall 117 itself is inclined upwardly from the lickerin to the condenser so that the upper and lower walls of the duct 55 recede from one another between the lickerin and the condenser to expose a Wide area of the condenser for laying of the web.

The duct 55 including the stationary part thereof that extends through the condenser, ducts 108 and 106, fan housing 105, and ducts 110 and 112 constitute a fully enclosed recirculatory air system. Such a system in itself provides for better distribution of the fibers across the condenser screen 57 and thus helps insure uniformity of thickness of the random web across its whole width. Moreover, the closed return-duct system makes the machine self-contained and compact; and its obviates any difi'iculty of air disposal.

The lickerin extends into the duct 55 for the major part of the depth of the duct so that the duct at the lickerin has the general shape of a Venturi tube with the result that the velocity of the air is accelerated considerably as it passes the lickerin and is that much more efiective in dofling the fibers from the lickerin. A hood 118 is provided over the lickerin; and a seal roll 119 is provided between the hood and feed roller 40 for air tightness. The hood 118 may be integral with or otherwise secured to plate 117. The seal roll 119 is held in position by gravity and the rotation of feed roller 49 anlcll revolves by its frictional engagement with the feed ro er.

Static may be controlled in a machine having a recirculating air system such as described in various ways. One method is by humidifying the air in the system. It is known that when textile fibers are handled in a humidified atmosphere static is reduced. Of course, machines might be installed in a humidified room and the fibers preconditioned in that way. But in such case, the air in the room would have to be as Wet as required for the worst condition to be encountered by the machines operating in that room. Thus, if there were some machines in the room operating on cotton fibers and other machines operating on wool fibers, the air in the room would have to be wetter than necessary for the cotton in order that the wool might be handled. However, if each machine is internally humidified, room humidity ceases to be a vital factor.

One way in which the air in a machine may be humidified is illustrated in Figs. 1, 2 and 7. In this arrangement, a small stream of air is by-passed from the pressure side of the blower or fan back to the inlet side. This auxiliary stream is taken from the duct 110 by means 7 of a sampling tube 120 which is mounted to project into the duct and which is provided with a plurality of holes 121 through which air may enter from the duct. This sample tube 120 is connected by a right anglular tube 122 with a U-shaped tube 123. The air by-passed is returned into the system through a duct 146 which connects U-shaped duct 123 with vertical duct 106.

Mounted in one leg of the U-shaped tube 123: is an electrical bayonet-type heater 125 which is connected with a main line L1 by a line 1% and which is connected with a main line L2 by a line 127, and a rheostat, the resistance of which is indicated at 128 and the movable element of which is denoted at 129. Adjustment of the rheostat controls the temperature of the electric heater 125.

in the other leg of the lJ-tube 123 is mounted a drybulb thermometer 13%. This thermometer is electrically connected with a thermostat 131 that operates a solenoid which controls an air valve. The solenoid and valve may be housed in the casing 133. Thermostat and solenoid are connected to one another electrically by the line 134, and the thermostat is connected electrically to the line L1 by the line 135 While the solenoid is connected electrically to the line L2 by the line 135.

The construction is such that when the temperature in the duct 123 is above a predetermined level, the air valve opens and causes air under pressure to be supplied iron. a pressure line Mil through a duct 141 to an atomizing nozzle 242 that is mounted in the right hand end of the frame 20 of the machine to extend into the vertical duct 1%. This is preferably just opposite the inlet to the fan. The atomizer sucks up water from a pan 44 through the tube 14-5 and sprays this in the form of fine droplets into the air entering the fan. Thus, water in the form of fine droplets will be supplied in the air system of the machine to humidity the air and offset the ert'ect of static or eliminate static entirely.

Both the heater element 125 and the thermostat solenoid should be connected in on the same push button control that turns on the feed motor 47.

The heater is adjusted to add suificient additional heat to the by-passed air so that all of the water added even in the super-saturated state will be evaporated as the air passes by the bayonet-heater. In operation of the machine, the lickerin motor 4'7 is first started, then the fan motor 101 (Fig. 4). The turning on of both these units causes the air stream to rise in temperature. Turning on the reed motor also energizes the heater thermostat solenoid valve circuit. The heater causes a further rise in temperature in the by-passed air stream. As this temperature rises, the temperature of the thermostat will pass the preset value and cause the solenoid to open the air valve to supply water to the main circulating air system.

A more or less continuous supply of water is required to condition the circulating air system since water particles collect on the fibers as they build up on the condenser screen, and this water is discharged from the machine with the product, namely, the random fiber web. The continuous discharge of water particles, which may also be increased by leakage of air from the circulating system past the seals into the atmosphere of the room, requires supply of water more or less continuously into the circulating air system to maintain the desired relative humidity or super-saturated condition.

The evaporative cooling obtained by the interaction of adding heat, which tends to raise the temperature, and at the same time adding water in an atomized spray actually results in a lowering of the temperature of the circulating air system. In fact, the temperatures in the air system have been observed to drop as much as 20 F. upon the addition or an atomized spray of Water to the circulating air stream.

it the thermostat temperature is set low enough relative humidity may be reached in the main circulating air stream. Beyond 100% relative humidity, that is, in the super-saturated condition, the bayonet heater causes further evaporation in the auxiliary or by-passed air stream which will cause further lowering of thetemperature in this stream. When this lowered temperature drops below the preset thermostat temperature, the solenoid valve closes and remains closed until the temperature has risen again above the thermostat temperature. In this way, supply of water into the air stream is stopped until the temperature has risen again above the thermostat setting. With the apparatus shown the efiective range of temperature drop due to adding moisture to an air stream is extended, thus permitting, if desired, a supersaturated condition in the main circulating system.

In a machine constructed according to the present invention, then, where the motors tend to heat up the recirculating air stream, the addition of water, which evaporates, tends to balance such added heat and consequently lowers the temperature of the air stream. Further additions of water, when evaporating, may fully absorb the work heat before the relative humidity has reached 100%. Therefore further additions of Water to bring about 100% relative humidity must draw heat through the frame and duct Walls, thus lowering the inter nal temperature of the air stream below room temperature.

in our machine, the fog of condensed moisture particles introduced into the air stream becomes carriers of static charges thus diminishing the intensity of the fiber charging. There is thus a double advantage with our construction; static electricity is not readily formed in high humidity atmospheres in the first place, and secondly, those charges that are formed are in part dissipated by the traveling liquid particles providing a lower static potential in the system as a whole.

Moisture may be added to the air stream in other ways also. For instance, a steam humidifier may be used. In this case, steam is admitted into the air stream, preferably ahead of the liclcerin, by means of a supply pipe 15% (Fig. 8) which is provided with a great number of small holes 151 spaced uniform distances apart across the width of the air stream. The admission of the steam may be controlled by a needle valve.

The high humidity produced by injecting steam into the air stream dissipates the static charges as rapidly as they are formed so that in effect they do not form in the first place. The steam condenses due to the steam entering the air at a relatively low temperature. Therefore, moisture is formed and carried to the critical points where the fibers are doffed from the lickerin. It takestirne and additional heat for these moisture particles to re-evaporate. They may again form into vapor, however, as long as the relative humidity is less than 100%.

In both cases, whether the water be admitted as liquid highly atomized or as steam, the static charges are more or less neutralized as they are formed. Moreover, the total static charge is materially reduced between the lickerin and the condenser by virtue of the millions of molecules or particles of liquid in the form of a mist or fog in the air stream. Each particle carries or accounts for a share of the charge previously generated and as compared to the relatively small number of fibers passing in the same zone is effective in reducing the eifects of static formation in the machine.

Another way of controlling static is by electrical neutralization of the static charge. This involves use of an alternating current of high voltage. In this case one end 156 of a high voltage transformer secondary winding, whose primary winding is indicated at 155, might be grounded to the frame 2'!) of the machine and the other end 160 of the winding attached to an inductor bar 161 (Fig. 9) that is insulated from the frame and mounted to project into the air stream. This in ductor bar may have a plurality of discharge points 162, located say an inch apart, attached to it inside of the air duct between the lickerin and the condenser. The high voltage at these points will alternate between positive and negative at so many times per second depending upon the cycle, for instance, 60 times a second if 60 cycle current is used. This alternating high voltage discharge will neutralize the fibers traveling in the air stream between the lickerin and the condenser in much the same Way as a watch is de-rnagnetized when passed in and out of a solenoid coil energized with alternating current.

If desired, a second inductor bar may be mounted in the air stream ahead of the lickerin as denoted at 165 in the drawings. This second bar will also be insulated from the frame and may have discharge points 166 on it that project into the air stream. This second inductor bar may be connected to the secondary coil of the transformer by a line 167. With this construction, it is possible to effectively ionize the air stream ahead of the lickerin.

Another way in which static may be eliminated is through installation in the air stream ahead of the lickerin of a radioactive type of static eliminator as denoted at 170 in Fig. 10. Other desirable positions for such a static eliminator may, however, be chosen. These static eliminators are a commercial product. They will release energy constantly of a particular wave length. This will radiate into the air stream and ionize the air molecules.

The operation of the machine will be understood from the preceding description. The work material is dumped into the hopper and fed forward by foraminous belt 31 over rolls 25, the suction of air produced by blower 32 acting all the while to draw in the loose stock into any voids with the result that a fiber sheet of uniform thickness throughout its entire width is fed onto feed plate 21 and fed over this plate by feed roller 40 to lickerin 45. The lickerin rotating at high speed combs the fibers out of this stock material and carries them around into the air tunnel. air stream, which has a velocity equal to or slightly greater than the surface speed of the lickerin, and the centrifugal force of the lickerin cause the fibers to be doifed into the air stream. The air stream carries them to the condenser which is rotating at relatively slow speed and they are randomly deposited on the condenser under the suction action of the fan 100. The recirculating air stream and static-neutralizing means insure uniformity of thickness of the random web over its whole width, while the speed of rotation of the condenser determines this thickness.

While the floor of the hopper is preferably perforated as by use of rolls 25, it might be made solid and air be sucked instead only through the stock and foraminous belt 31.

The suction of the stock which is in chunks or loose, but the machine may be used also in the making of random webs from material in other forms, for instance, from a roll of ma terial such as comes from a cotton picking machine. In this case, the brackets 34 and hopper 22 will be taken off the machine and brackets substituted in place thereof. These brackets are slotted to receive the mandrel of the roll on which the work material is wound. This roll may rest upon a roller 176 which is suitably journaled in the brackets 175. The picker-lap from the roll is fed over the feed plate 21 by the feed roll 40 into the lickerin. Otherwise the machine may be of the same construction as already described and operate in the same way.

While a number of different embodiments of the invention have been described, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth and as fall within the scope of the invention or the limits of the appended claims.

Having thus described our invention, what we claim is:

l. A machine for forming a random fiber web comprising a rotary lickerin, means for feeding stock material to the lickerin so that in its rotation the lickerin doffs fibers from the material, an air duct into which the lickerin projects, means for effecting high speed air flow in the duct, a movable foraminous member intersecting said duct at a point spaced from the lickerin in the direction of air flow, said air duct being wholly closed so that the air in the duct is continuously recirculated, means for heating air of the duct, and means operable when the air reaches a predetermined temperature to add water to the air stream.

2. A machine for forming a random fiber web comprising a rotary lickerin, means for feeding stock material to the lickerin so that in its rotation the lickerin doifs fibers from the material, an air duct into which the lickerin projects, a fan for effecting high speed flow of air in the duct, a movable foraminous member intersecting said duct at a point spaced from the lickerin. in the direction of air flow, said air duct being wholly closed, a closed auxiliary duct communicating with said first-named air duct at opposite sides of said fan, means for heating air flowing through said auxiliary duct, and thermostatically operated means for supplying water to said first-named duct when the temperature in the auxiliary duct exceeds a predetermined amount.

3. A machine for forming a random fiber web of uniform thickness across its whole width comprising a frame, a lickerin rotatably mounted in said frame, means mounted on the frame for feeding stock material to the lickerin so that in its rotation the lickerin dotfs fibers from the stock material, an air duct into which the lickerin projects, a fan mounted in said duct for effecting high speed flow of air in said duct to provide an air stream for aiding in dofiing fibres from the rotating lickerin and for carrying the doffed fibres, a movable forarninous condenser mounted in said frame to intersect and pass through said duct at a point spaced from the lickerin and between the lickerin and said fan, said lickerin and said condenser being of. approximately the same width and of at least the same width as the duct at the points where they enter the duct, and the depth of said duct being narrowed, Where the lickerin projects into it, by the projection of the lickerin, said duct extending from said lickerin to said condenser and in a straight line through said condenser, thence to said fan, and from said fan back to and past said lickerin to its start, said duct being closed to form a closed conduit for the air stream so that air in the duct is continuously recirculated therein by the fan, means projecting into said duct and operative to add water to the air stream in excess of that which would be carried at the average working temperature of the air stream, and control means communicating with said duct and responsive to the humidity of the air in said duct for actuating the last-named means to maintain automatically a predetermined humidity in the air stream.

4. A machine for forming a random fiber web of uniform thickness across its whole width comprising a frame, a lickerin rotatably mounted in said frame, means the lickerin so that in its rotation the lickerin dofis fibers from the stock material, an air duct into which the lickerin projects, a fan mounted in said duct for eifecting high speed flow of air in said duct to provide an air stream for aiding in doffing fibres from the rotating lickerin and for carrying the dotted fibres, a movable foraminous condenser mounted in said frame to intersect and pass through said duct at a point spaced from the lickerin and between the lickerin and said fan, said lickerin and said condenser being of approximately the same width and of at least the same width as the duct at the points where they enter the duct, and the depth of said duct being narrowed, where the lickerin projects into it, by the projection of the lickerin, said duct extending from said lickerin'to said condenser and in a straight line through said condenser, thence to said fan, and from said fan back to and past said lickerin to its start, said duct being closed to form a closed conduit for the air stream so that air in the duct is continuously recirculated therein by the fan, temperaturecontrolled means communicating with said duct so as to be affected by the temperature of the air in said duct, means for variably adding moisture to said stream, said 10 moisture-adding means projecting into said duct between the condenser and the lickerin in the direction of air flow, and said moisture-adding means being automatically controlled by said temperature-controlled means.

References Cited in the file of this patent UNITED STATES PATENTS 187,538 Kitson Feb. 20, 1877 588,812 Bessonette Aug. 24, 1897 1,190,697 Windell July 11, 1916 1,761,493 Rogers June 3, 1930 1,767,957 Bachman June 24, 1930 1,785,823 Thoma Dec. 23, 1930 1,941,104 Moss Dec. 26, 1933 2,057,369 Curley Oct. 13, 1 936 2,068,587 Aldrich Jan. 19, 1937 2,206,297 Curley et a1 July 2, 1940 2,420,035 Fairbairn May 6, 1947 2,451,915 Buresh Oct. 19, 1948 FOREIGN PATENTS 374,686 Great Britain June 16, 1932 744,890 France Jan. 31, 1933

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