US2573321A - Defibering apparatus - Google Patents

Description

O ct. 30, 1951 A. F. ERNST DEFIBERING APPARATUS Filed Jan. 19, 1946 Patented Oct. 30, 1951 DEFIBERING APPARATUS Alfred F. Ernst, Larchmont, N. Y., asslgnor to Certain-teed Products Corporation, Chicago, lll., a corporation oi Maryland Application January 19, 1946, Serial No. 642,267

1 claim. l

This invention relates to deflbering apparatus of a type in which wood chips or other fibrous growth material are fed into a pressure chamber containing steam at or above a temperature of 212 F. so as to soften the lignins or other incrustsubstances by which the bres are held together in the fibrous growth material, the`iibrous materials being subjected to a mechanical fibreloosening operation within the pressure chamber in the absence of water or other liquid in an amount sutlicient for suspending the bres, and being then discharged from the pressure chamber. Such mechanical debering in a gaseous atmosphere is disclosed by Asplund Patent No. 2,008,892, dated July 23, 1935.

It is one of the objects of this invention to provide improved apparatus for deflbering fibrous growth materials by the use of structure comprising an improved arrangement of means for withdrawing the fibres from the pressure chamber, and comprising preferably an elongated outlet conduit provided with pressure reducing means constructed and arranged so as to control to great advantage the escape of steam and iibres from the pressure chamber while at the same time limiting the ow of the steam and thus maintaining` the desired steam pressure in the pressure chamber. For carrying out this object, I have employed a construction comprising -an elongated outlet conduit serving to provide an increased period for the benecial action of the steam for modifying to the desired extent the condition of the incrusting Substances carried by the fibres, and an increased period for the action of sodium hydroxide or other chemical agent introduced into the outlet conduit of such improved y construction for enabling such chemical agent to act to advantage on the fibres and the encrusting substances carried by the fibres for making such bres softer and more flexible.

The preferred form of means for controlling the withdrawal of the steam and bres from the pressure chamber as disclosed by this application4 comprises means in the form of a Venturi tube in the outlet conduit having a restricted opening of small size as comparedwith that of the major portion of the outlet conduit, adapted to permit' tween the Venturi tube and the pressure chamber .so as to be adapted to cooperate with such Venturi tube for the complete control of the discharge of the steam and fibres.

It is another object of this invention to improve devices of this type in sundry details hereinafter set forth. 'I'his application is being filed as a continuation-in-part of my prior application Serial No. 364,039, filed November 2, 1940, now abandoned. The preferred means by which I have accomplished my several objects are illustrated in the accompanying drawing in which:

Fig. 1 is a diagrammatic view of a preferred form of my improved apparatus; and

Fig. 2 is a diagrammatic view of a modified form of apparatus.

In Fig. 1, I have shown one type of debering apparatus suitable for carrying out my improved process, the major portion of such machine corresponding with the machine shown by said Asplund Patent No. 2,008,892. Ihis apparatus comprises a steam chamber I having 'an opening at 3 through which the brous material which may be in the form of chips of wood is introduced by means not shown, against the pressure of steam delivered to the chamber I through a pipe 5 controlled by a valve 6. The steam is supplied at such pressure and the valve is to be controlled so that a pressure is maintained within the chamber I above atmospheric pressure and so as to maintain a temperature above 212 F.

At the lower end of the chamber I, the feed screw I is provided for carrying chips from the chamber into and along a conduit 8 toward the left in said Fig. 1, such screw being supported by a shaft 9 rotatably mounted in the wall of the chamber and arranged to be driven by means of a chain I0 and sprocket II. With the screw 1 rotating in the predetermined direction, chips falling into engagement with the screw are carried along the conduit 8 with the lignins or other incrusting and bondingsubstances of the wood holding the bres in their original bundled form but with such incrusting substances substantially softened by the action of the steam.

At the outer end of the conduit 8, the chips are delivered to toothed defbering discs I2 and I3 within a suitable casing I4, the disc I2 being mounted rigidly in position and the disc I3 be-l ing rotatably mounted by means of a heavy shaft I5 driven by a belt I6 and pulley I1. In the arrangement shown, the rotatably mounted disc I3 ls supported in position by means of a rotor body I8, which is provided on its periphery with a series of outwardly lextending vanes, I9. At its 3 upper edge, the casing I4 communicates with an outlet conduit 20 through which the bres escape from the casing I4. Stufling boxes of any approved type are preferably provided in connection with the lshafts 9 and I5.

In the normal use of the machine as above described, chips or other fibrous growth material are fed into the chamber I through the opening 3 against the pressure of steam in the chamber, such fibrous material dropping into engagement with the screw 1 by which it is carried at the desired speed of movement toward the deflbering discs I2 and I3, with the incrusting substances of the chips being softened by the effects of the steam as the material moves along the conduit 8. At the end of the conduit 8, the chips are fed by the screw between the discs I2 and I3, by which the bundles of fibres making up the chips are quickly and easily torn apart so as to leave the fibres largely in individualized form while still carrying the softened incrusting substances thereon. As the fibres move outwardly from the discs I2 and I3, such fibres are engaged by the vanes I9 and forced into the outlet conduit 20, together with the-steam which passes outwardly between the discs with the fibres. For insuring that the required amount of steam shall be present in the casing I4 and in the conduit 20, I have provided a steam pipe connection 2| leading from the upper end of the chamber I and opening into ther/Tower part of the casing n. /f

In the arrangement shown in Fig. l, intermittently operating valve mechanism 22 is provided at the outlet conduit 2D, such valve mechanism corresponding with that disclosed by said Asplund Patent No. 2,008,892, by which a limited amount of steam and fibres is admitted first to the space 23 between the valves and is then discharged beyond the valve mechanism into the portion of the Aconduit leading in the arrangement shown to a cyclone or condenser device 24. In the construction illustrated, the portion 25 of the outlet conduit next adjacent to the cyclone device 24 is of smaller size than that of the portion of the conduit adjacent to the casing I4, a Venturi tube 26 being interposed in the conduit between the sections of different size, such Venturi tube comprising a throat portion of substantially smaller size than that of the portion 25 of the conduit.

With the pressure of steam being maintained in the casing I4 above atmospheric pressure, the individualized bres are carried by the pressure along the outlet conduit past the valve mechanism 22 and the Venturi tube, there being a reduction in the pressure of the steam within the outlet conduit portion beyond the valve mechanism and the throat of the Venturi tube as compared with the pressure in the conduit adjacent to the casing I4. The advance portion 25 of the conduit may be of any desired length, but it is not to Abe so prolonged as to prevent the steam from carrying the fibres along the conduit for delivery into the cyclone device 24. The conduit may be insulated, if desired, so as to insure .that the heat content of the steam and fibres shall not be dissipated before the delivery of the fibres to the cylone device.

In the arrangement shown in Fig. l, I have provided for the delivery of sodium hydroxide or other suitable chemical intothe reduced size portion of the conduit beyond the Venturi tube, by means of a pipe 21 opening into the Venturi tube adjacent to the throat. In this arrange- 4 ment. the chemicals are preferably forced in solution form through the pipe 21 under the control of a valve 28 and a pump 29 by which the solution is drawn from a suitable tank 30.

In the movement of the fibres through the full length of the outlet conduit 20, including the reduced size portion 25, the bres are subjected to the effects of the steam by which the incrusting substances on the bres are substantially softened. In the movement of the fibres through the reduced size portion 25 of the conduit, the incrusting substances are acted upon by the chemicals injected through the pipe 21, by which at least a portion of the incrusting substances are chemically affected so as to secure the desired degree of softness and flexibility of the fibres.

In the arrangement shown in Fig. 2, a debrator 3l is shown diagrammatically, being of the same type as that shown in Fig. l, with an outlet conduit 32 leading therefrom corresponding to the outlet conduit 20 of the arrangement of Fig. 1. In this modified form of apparatus, valve mechanism 33 is employed corresponding to the valve mechanism 22 of Fig. l, such valve mechanism 33 being intermittently operated for permitting limited quantities of steam and fibres to move along the outlet conduit beyond the valves. At the outer end portion of the outlet conduit 32, a Venturi tube 34 is provided, connected by a short tube 35 with a cyclone device 36. The principal difference between this arrangement of Fig. 2 and the arrangement of Fig. 1 resides in the fact that in Fig. l the Venturi tube is positioned adjacent to the valve mechanism, with a substantial length of outlet conduit between the valve mechanism and the cyclone device, while in the Fig. 2 construction the Venturi tube is positioned adjacent to the cyclone device with substantially the whole length of the outlet conduit between the Venturi tube and the valve mechanism.

In the arrangement shown in Fig. 2, chemicals are to be injected into the outlet conduit by means of a pipe 31 controlled by a valve 38 and a pump 39 adapted to draw the chemicals from a.` suitable tank 40. In the use of this Fig. 2 construction, with the means by which the escape of the steam is controlled located at the outer end portion of the outlet conduit, the pressure of the steam acting on the fibres in their movement along the outlet conduit is higher than the pressure in the conduit portion .thereof between the Venturi tube and the cyclone device, and the effect of the steam is accordingly increased. In this arrangement, the effect of the chemicals on the fibres may be cut down more or less, in view of the comparatively shorter length of the conduit portion 35 through which the fibres move in contact with the chemicals, but the invention is not to be limited to the arrangement shown except so far as the claims are so limited in terms, it being understood that changes might well be made in the form and arrangement of the parts without departing from the spirit of the invention.

I claim:

A debering apparatus comprising in combination, a pressure chamber; fibre-feeding means operatively connected with said pressure chamber for supplying brous growth material to said chamber; a steam feeding conduit in communication with said chamber for introducing steam into said chamber; mechanically operating debering apparatus disposed in said chamber for separating from each other the fibres fed into 'said chamber; a discharge outlet in communication with said chamber, -said discharge outlet conduit comprising two portions of substantially different diameters and having a venturi disposed between said portions at the juncture thereof, the conduit portion of larger diameter being disposed between said venturi and said chamber, the venturi being in full communication with both portions of said conduit and having a diameter which is substantially smaller than the diameter of either of said portions of said conduit but of sufcient diameter the separated fibres discharged from said chamber under the pressure of the steam introduced therein pass through said venturi; an intermittently operable valve disposed in said discharge outlet means between said chamber and said venturi; and an injector for forcing a chemical treating medium into said conduit in a direction counter to the direction of flow of steam and fibre therethrough, said injector being disposed substantially adjacent the most constricted portion of said venturi and opening into the portion of said conduit having the smaller diameter.

ALFRED F. ERNST.

. REFERENCES CITED UNITED STATES PATENTS Number Name Date Re. 19,288 Bacchus Aug. 28, 1934 1,367,895 Schouten Feb. 8, 1921 1,824,221 Mason Sept. 22, 1931 1,922,313 Mason Aug. 15, 1933 2,007,348 Scharmann July 9, 1935 2,008,892 Asplund July 23, 1935 2,045,818 Adams June 30, 1936 2,145,851 Asplund Feb. 7, 1939 2,265,622 Basler Dec. 9, 1941 2,300,184 Turner Oct. 27, 1942 2,323,194 Beveridge June 29, 1943 2,405,213 Heritage Aug. 6, 1946 FOREIGN PATENTS Number Country Date 473,708 Great Britain Oct. 19, 1937 99,120 Sweden Apr. 11, 1940 OTHER REFERENCES Der Papier Fabrikant Wochenblatt fur Papierfabrikation Heft 2, May 1943, Pages 57-60.

Images