US2743874A

US2743874A - Disk type grinding apparatus for fibrous materials

Info

Publication number: US2743874A
Application number: US299878A
Authority: US
Inventors: Asplund Arne Johan Arthur
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-07-19
Filing date: 1952-07-19
Publication date: 1956-05-01
Anticipated expiration: 1973-05-01

Description

May 1, 1956 A. J. A. ASPLUND 2,743,874

DISK TYPE GRINDING APPARATUS FOR FIBROUS MATERIALS Filed July 19, 1952 3 Sheets-Sheet l BY rit Y )1 mo HH'orneY May 1, 1956 A. J. A. ASPLUND 2,743,874

DISK TYPE GRINDING APPARATUS FOR FIBROUS MATERIALS Filed July 19, 1952 a Sheets-Sheet 2 firm juhan Arthur fisplund INVENTOR.

BY {Nb 'Y- M Ht -nq y 1, 1956 A. J. A. ASPLUND 2,743,874

DISK TYPE GRINDING APPARATUS FOR FIBROUS MATERIALS Filed July 19, 1952 3 Sheets-Sheet 5 firm Echo Hrflur H s almnd.

INVENTOR.

BY mu Y' "we United States Patent DISK TYPE GRINDING APPARATUSFOR FIBROUS MATERIALS- Arne Johan Arthur Asplund, Hoglandet, Bromma, Sweden Application July 19, 1952, Serial No. 299,878- 7 Claims. (Cl. 241-42) The present invention relates to a grinding apparatus particularly adapted for operationupon fibrous materials, such as paper pulp, and the apparatus to which the invention has reference is one which includes a rotatable disk-like grinding member and a cooperating stationary grinding member, also of disk-like formation. In a machine of this character, the rotatable grinding member is carried on a shaft that is axially displaceable or movable to permit of the desired spacing of the grinding members relative to one another andalso to regulate the compressive pressure exerted upon the material that is introduced. between said members; The apparatus is primarily intended for operation upon a fibrous material in more or less separated form, for the purpose of sep.-- arating fibre bundles and elfectinga certain disintegration of the fibresthemselves. The fibrous material so treated is subsequently utilized for the manufacture of paper, pasteboard, fibre board and similar products. The ap paratus to be described, however, is: not. limited to suchspecific use since it can also be used for the Working. of many grainy and pulverulent materials.

In order to enable favorable results to be obtained in the disintegration of fibrous materials, and particularly those which have been previously partly separated by steam treatment, it is important that the workingv surfaces of the grinding disks be adjusted relatively toone another with such accuracy that. the deviation from their parallelism, measured around the circumference, only amounts to one or afew'hundredths of a millimeter. As the disks have a diameter frequently amounting to onemeter and the compressive pressure is applied to the free end of the shaft on which the rotative disk is: mounted, which free end of the shaft is located at a distance from the disks far greater than the diameter of the disks, it will be readily apparent that this accuracy with respect to the relative positions of the grinding disks places extraordinary demands upon the precision of adjustment of the machine. In practical prior devices the: frame construction of the machine had to be such as to necessitatethe mounting of the hood enclosing the grinding disks into its position before any fine adjustment of the grinding disks could be effected and this made the adjusting. task exceedingly difiicult.

It is therefore a primary object of the present invention to provide an improved construction for an apparatus. of this character by means of which a more uniformly ground product will be produced.

It is an object of the invention to provide, in an apparatus of this character, means by which the compressive pressure imposed by the grinding disks shall be produced by operation of a plunger that is: caused to be urged inv either of two directions by a compressive fluid system, said plunger being mounted in a stationary housing. A further feature of the invention contemplates the provision of a rotatable shaft mounted in bearings which are axially adjustable to thereby enable the rotative grinding disk on said shaft to be adjustedv to or from the Sta-- tionary grinding disk in a manner to be explained.

ice

It. is another object of the invention to provide means by whichthe stationary grinding disk is adjustablymount.- ed; to provide an. improved adjustable means for said stationary grinding disk and to provide housing. structure, shaftesupporting means, and other constructional: elements resulting in an improved: apparatus. andadvantageous grinding results.

With the above objects and other objects to be hereinafter set forth, in view, I have devised the arrangement of parts to be described and more particularly pointed out in the claims appended hereto,

In the accompanying drawings, wherein apreferred embodiment of the invention is disclosed,

Fig. 1 is a vertical longitudinal sectional view through an apparatus constructed according to the invention. and adapted for the working of paper pulp;

Fig. 2 is a sectional view taken on the line II--II of Fig. 1, looking in the direction of the arrows; and

Fig. 3 is a vertical sectional view through that portion of the apparatus shown at the left end of Fig. 1.

Referring to the drawings, 10 indicates a fixed but ad.- justable grinding disk, and 12 designates the rotatable grinding disk of the apparatus. These disks may be: of any known construction and may be provided with parallel channeled grinding surfaces 14. The stationary grind ing disk 10- is'rigidly connected to a support 16 at one end of the machine frame, by means of a plurality of circumferentially-spaced bolts 18. The grinding. surface of the stationary disk 10 may be adjusted relatively to. the plane of rotation of. the rotatable disk 12 by means of the bolts 20 threadable through the support. 16; In addition to the support. 16,. the frame also includes a second support 22 located adjacent to the opposite: end of the frame, the two supports 16 and 22 being secured to a bottom plate 28 by means of bolts 24, and being. also connected at the top by a longitudinal tie-bar 30 secured to the two supports 16 and 22 by means of bolts 26. The rotatable grinding disk 12 is detachably securedto a rotor 32, which is in turn secured to a flange 34 provided on a shaft 36. The shaft 36 is mounted in two ball bearings 38, 40 respectively supported by the bearing, standards 42 and 44 secured to and rising from the bottomplate 28. Between the standards 42 and 44,. a transmission member such as a pulley 46, is splined on the shaft'36. A bearing housing. 48, enclosing the ball bearing 40,. is axially displaceable in the standard located remotely from the rotatable grinding disk 12. In addition to containing the ball bearing 40, the bearing housing 48 contains an axial thrust bearing 50, said thrust bearing. having for its object the transference of the compressivepressure acting. upon the grinding; disks, from the bearing. housing 48"to the shaft 36.

The fibrous material to be operated upon is-fed into the apparatus through a central passage 52 in the support 16, by any suitable means and preferably by means of the screw conveyor shown at 54. After passing through the passage 52,. the material is then moved outwardly between the

disks

10 and 12 to the grinding surfaces 14,. to be then collected after the grinding operation in a housing 56 out of which. the materialv passes by way of the outlet 58 shown in Fig. 2. The housing 56 is divided into twosections in a vertical plane parallel to the axis of the shaft 36. The housing 56 is clearly shown in Fig. 2,- wherein it will be seen that its two sections arev provided at the top with lugs 60 secured to the tie-bar 39 by means of the transverse bolts 62. The support 16 has a projection or foot 63 extending between lugs 65- projecting downwardly from the two sections of the housing 56,. and bolts 64 extend through said lugs and through the pro-- jection or foot 63, as clearly seen in the lower portion of Fig.2. The housing. 56 extends from thesupport 16 against which it is sealed, and which cooperates with the casing 56 in constituting a wall of the housing and thus forming an enclosure about the

grinding disks

10 and 12. The housing 56 is also formed with a boss 56a fitting around the shaft 36. A packing ring 66 may be disposed between the shaft 36 and the boss 56a. The tie-bar 30 which, during operation of the machine, is subjected to tensile strains, has a cross section relatively large in comparison to its breadth and at the same time is so shaped as to enable the two parts of the housing 56 to be brought into position only after the grinding

disks

10 and 12 have been mounted and adjusted.

The setting of the grinding

disks

10 and 12 of the machine is effected hydraulically by means of a plunger or piston 70 moved by fluid under pressure, said plunger or piston 70 being mounted in a housing 72 extending through an opening in the support 22 and having a flange 75 secured to said support 22 by means of bolts '74. he plunger 70 is slidable within a piston-chamber '76 which is internally cylindrical to conform to the plunger 70 and is closed at one end by a cover 78 while being sealed at the other end by the cylindrical extension 80 provided on the plunger, and which has a diameter smaller than the diameter of the plunger, and which is slidable through a bore 82 in the housing 72. The plunger 70 is also provided with an axially extended shaft portion 84 projecting outside of the housing 72 and being rigidly connected to the axially displaceable bearing housing 43 by means of a flange 86 and bolts 87. The movement of the plunger 70 in a direction toward the stationary grinding disk 10 is limited by the extension 80 bearing against a nut 88 through which shaft 84 is slidable, said nut being threaded into the housing 72. The nut 38 is adjustable to a desired position and when the desired adjustmeut has been obtained, it is locked in such position by means of a lock nut 90.

A suction conduit 94 extends from a fluid supply tank 92 for fluid, such as oil, under pressure. The conduit 94 extends from the tank 92 to a pump 96 driven by means of a motor 98. The pressure conduit 10% of the pump 96 opens into a valve housing 1 .12 having a slide valve movable therein and generally designated at 164. Two conduits designated respectively at -6 and 103 extend from the valve housing 102 to the plunger chamber 76 where they respectively open on each side of the plunger 70. The valve housing 102 also has two return conduits 110, 112 connected to it and joined together into a common conduit 114 extending to the tank 92.

The slide valve 104 has three

piston portions

116, 118 and 120 having a tight sliding fit with the interior surface of the valve housing 102, said piston portions being separated by sections of a smaller-diameter shaft while being so arranged relatively to the several conduits that oil under pressure from the pump 96 will, in re sponse to the position of the valve, be supplied to the chamber 76 on one or the other side of the plunger 70, while oil on the opposite side of the plunger is at the same time permitted to escape and flow into the tank 92. The valve 104 is adjustable from the outside of the housing 102 by means of the button 122.

In the position shown in Fig. 3. the pressure conduit 100 is shown in communication by way of the conduit 106 with the space 76 in housing 72 to the left of the plunger 70. At this time there is communication between the space in the housing at the opposite side of the plunger 70 and the tank 92 by way of the conduit 108, the valve housing 102 and the conduits 112 and 114. At the same time, the piston portion 116 is shutting off entrance to the conduit 110. Arranged in a conduit 124 that connects the pressure conduit 10% with the tank. 92 is a return valve 126, which is preferably spring-loaded and adjustable in a known manner so as to open at a certain maximum pressure. The pressure in'the conduit. 100 may beascertained from a pressure gauge indicated at 128.

When the two

disks

10 and 12 are set up against one another, the oil pressure acts on the whole end surface of the plunger 70, whereas when the grinding disks are separated from one another, the oil pressure acts only on the ring surface defined by the difference between the diameters of the plunger 70 and its extension 80. The plunger 70 and its extension do not rquire any special packing in their cylindrical contacting surfaces, but are shaped to secure an accurate sliding fit in their respective bores in the housing 72. It is desirable to so arrange this fit that play will be smaller between the plunger 70 and its chamber 76, than the play between the extension 30 and its bore 82. In spite of the greater loss through leakage resulting from the looser fit between the extension 80 and its bore 82, it has been found that the plunger 70 may be moved more rapidly when separating the grinding disks than is the case when setting them against one another, due to the fact that the quantity of oil under compression required per unit of the length of plunger movement will be considerably less in the former case. Oil leaking out along the extension 80 is collected in a chamber in the housing 72 and is returned to the tank 92 by means of the conduit 1.32.

A rod 134 is mounted for axial slidable movement through parts of the housing 72. Said rod is provided with a projecting arm 136 which is held against the rear end of the extension 80 by means of a coil spring 133 in a manner to cause the rod 134 to follow the plunger 70 in its sliding movements in both directions. A rod 140 is adjustably attached to the rod 134 by means of a screw 142. The free end of the rod 140 bears against the movable measuring pointer 143 of a measuring instrument 144. The casing of the measuring instrument 144 has a cylindrical extension 145 adapted to be adjusted relatively to the housing 72 by means of a screw 146 or similar means, in such a manner that the pointer of the instrument will assume zero position when the working surfaces 14 of the grinding

disks

10 and 12 are in contact with one another. The instrument 144 is preferably of such a construction as to permit reading of the movements of the plunger 70 with an accuracy of 0.01 millimeter. The measuring range of the instrument 144 comprises approximately the portion of the path of movement of the plunger 70 corresponding to the distances between the grinding

disks

10 and 12 which are typical for carrying the grinding operations into effect, and during which the arm 136 abuts against the extension 80.

It frequently happens that foreign bodies, such as small pieces of scrap iron, stones and the like, find their way into the apparatus and produce a rapid increase of the grinding pressure by pressing and holding the grinding disks apart. To prevent detrimental eifects through too great strains caused by such an occurrence, the device includes a safety device 147 inserted into a conduit 148 connecting the portion 76 of the plunger chamber on the left of the plunger 70 as shown in Fig. 3, with the supply tank 92. The safety device 147 may consist of a diaphragm which normally completely closes the conduit 148, but which on the rapid creation of a powerful pressure surge in the chamber 76 of such force that the control valve 126 will not have time to equalize it, bursts and rapidly reduces the oil quantity in the chamber 76. The conduit 148 may be connected to the valve housing 102 by means of a branch conduit 150 in such a manner that the liquid pressure produced in the conduit 148 slides the valve 104 to the left so as to establish communication between the conduit 106 and the return conduit 112. In order to then insure the oil escaping past the diaphragm 147 having time to immediately act upon the valve 104, the portion of the conduit 148 between the piston chamber 76 and the conduit 150 is always filled with oil, at least for its greater part. This oil may be supplied from the pressure conduit 100 through a conduit 152 having a cut-off valve 154 and a non-return valve 156 arranged therein. The conduit 148 may have an upwardly extending loop 158 preventing the oil located in conduit 148 from escaping. Provided on the conduit 148 is an electric release 160, which, upon creation of a pressure surge in the conduit 148 interrupts the feeding operation into the machine.

Having described one embodiment of the invention, it is obvious that the same is not to be restricted thereto, but is broad enough to cover all structures coming within the scope of the annexed claims.

What I claim is:

l. A grinding apparatus for fibrous materials, including a stationary grinding disk, a rotatable grinding disk for cooperation therewith, the rotatable grinding disk being carried by an axially movable shaft to thereby control the spacing of the rotatable disk relative to the stationary disk and to control the compressive pressure exerted by the disks on material introduced between them, a housing in which a piston is slidable, a piston in said housing, the piston having an extended end portion located externally of the housing and coupled to the axially movable shaft, stop means for limiting the movements of the piston in a direction toward the grinding disks, a fluid pressuse system for introducing fluid under pressure into the housing at both ends of the piston, and means for indicating movements of the piston comprising a slidable member mounted on the housing and having a projecting element in engagement with the piston, spring means for maintaining said element in engagement with the piston, and an indicating instrument coupled to said slidable member.

2. A grinding apparatus for fibrous materials including a rotatable grinding disk and a stationary disk, a shaft on which the rotatable disk is carried, said shaft being axially movable for the adjustment of the rotatable disk relative to the stationary disk and for the regulation of the compressive pressure exerted on material introduced between them, a frame having a supporting member at one end, the stationary disk being adjustable in said supporting member, a support at the opposite end of the frame, means at the top and bottom of the supports for connecting the same, a driving pulley on the shaft, and bearings on the shaft on one side only of the disks, the bearings and pulley being located between the top and bottom supports of the frame.

3. In a grinding apparatus of the character described, a frame including a vertical support at each of its ends, a stationary grinding disk, a rotatable grinding disk for cooperation therewith, an axially movable shaft on which the rotatable grinding disk is mounted, a two-section housing extending around the disks, one section of said housing having a material outlet, one of the vertical supports constituting a wall for said housing, said support having an extension, lugs on the sections of the housing embracing said extension between them and bolted thereto, the frame including a top bar extending between and connected to the vertical supports, and lugs at 'the top of the sections of the housing embracing said top bar and being bolted thereto.

4. In a grinding apparatus of the character described, including a stationary grinding disk, a rotatable shaft carrying a grinding disk rotatable with said shaft, bearings in which said shaft is rotatively supported, a housing in which one of the bearings is contained, said housing being movable in a direction axially of the shaft, said housing containing a thrust bearing connected to the shaft, a hydraulically-movable piston having one end attached to the bearing, and afluid pressure system for supplying fluid at either of both ends of the piston.

5. In a grinding apparatus, a stationary grinding disk, a rotatable grinding disk for cooperation therewith, a frame including a vertical support to which the stationary disk is adjustably secured, a housing enclosing the disks,

the support constituting a wall of said housing, the support having an extended foot to which the housing is attached, the frame including a longitudinally extending tie bar extending between and secured by opposite ends of the frame, and lugs at the top of the housing between which the tie bar is positioned and to which the tie bar is bolted.

6. A grinding apparatus for fiubrous materials, including a stationary grinding disk, a rotatable grinding disk for cooperation therewith, the rotatable grinding disk being carried by an axially movable shaft'to thereby control the spacing of the rotatable disk relative to the stationary disk and to control the compressive pressure exerted by the disks on material introduced between them, a housing in which a piston is slidable, said housing having large and small diameter'parts, the piston having a part movable in the large-diameter part and havinga smaller-diameter portion slidable through the smaller-diameter part of the housing, an extension projecting from the end of the smaller-diameter part of the piston and protruding out of the housing and connected to the axially movable shaft to thereby transmit thereto the movements of the piston, a fluid pressure system for providing fluid under pressure within the largerdiameter part of the housing on either of the opposite ends of the larger-diameter part of the piston, and means in contact with the end of the smaller-diameter part of the piston and within the housing for reproducing on an indicator the movements of the piston.

7. A grinding apparaus for fibrous materials, including a stationary grinding disk, a rotatable grinding disk for cooperation therewith, the rotatable grinding disk being carried by an axially movable shaft to thereby control the spacing of the rotatable disk relative to the stationary disk and to control the compressive pressure exerted by the disks on material introduced between them, a housing in which a piston is slidable, the piston having an extension projecting through a part of the housing, said extension being connected to the axially movable shaft to thereby transmit thereto the movements of the plunger, a fluid pressure system for providing fluid under pressure within the housing on either of the opposite ends of the piston, said fluid pressure system including a normally inoperative safety device which becomes operative upon the creation of extremely high pressure between the grinding disks to thereby open and relieve the liquid pressure in the housing at one end of the piston, said fluid system also including an emergency valve directing in response to its position the fluid to one side or to the other side of thepiston, and a conduit extending from the safety device to the said emergency valve and operative upon the operation of the safety device to cause operation of the emergency valve in a manner to relieve fluid pressure on the plunger.

References Cited in the file of this patent UNITED STATES PATENTS 332,234 Case Dec. 15, 1885 614,316 Baker et a1. Nov. 15, 1898 1,146,030 Snyder July 13, 1915 1,146,033 Sorensen July 13, 1915 1,570,456 Bryant Ian. 19, 1926 2,079,882 Traylor May 11, 1937 2,101,442 Martinez Dec. 7, 1937 2,156,320 Sutherland May 2, 1939 2,182,900 McIlvried et al Dec. 12, 1939 2,338,198 Pall Jan. 4, 1944 2,377,307 Brown June 5, 1945 FOREIGN PATENTS France Mar. 19, 1952