US1750088A - Grinding mill - Google Patents

Description

T. BRAGARD March l1, 1930.

GRINDING MILL Filed July 3, 192g Patented Mar. 11, 1930,

UNITED STATES THEODOR BRAGARD, OF HAMBURG, GERMANY, ASSIGNOR WALZENMUKLEN-GESELLSCHAFT MIT BESCHBANKTER GERMANY TO FIRM OF MzCAO- HAFTUNG, OF HAMBURG,

GRINDING MILL Application led July 3, 1928, Serial No. 290,115, and in Germany June 9, 1927.

This invention relates in the first place to a grinding device in which the end faces of several planetarily driven grinding discs cooperate with an annular grinding disc located within a casing, and in the second place to a mill in which the planetarily rotatable grinding discs are rigidly connected with rolls performing planetary rotation around a central shaft, said rolls belonging to a roller mill, known per se, tted in the same casing. The combined mill in which the goods are preferably first fed to the set of rolls and are eX- pelled by the pressure of the latterdirectly to the set of grinding discs is particularly adapted for the treatment of plastic masses, such as paints, which can ,be ground to the finest sizes. Preferably all the grinding bodies are formed of hard porcelain and all the metallic parts which contact with the goods are enamelled. l v

In the accompanying drawing is illustrated by way ofeXample a construction according to the invention. f-

Fig. 1 is a vertical longitudinal section through the combined mill. Fig. 2 shows a modified form of feeding device. Fig. 3 is a section of the line A-A of Fig. 1 viewed from the left and shows the rotatable grind'- ing discs in one position. Fig. 4 is a section on the line AA of Fig.v 1 showing the grinding discs in a position of 180 displaced from the position of Fig. 3. Fig. 5 is a section on the line A-#A of Fig. 1 viewed from the right. Fig. 6 is a section on the line B-B of Fig. 1 viewed from the left. Fig. 7 is a section on the line B-B of Fig. 1 viewed from the right.

As shown in the drawing, the invention is incorporated in a mill including a central roll 1 and rolls` 2 performing planetary rotation around the roll 1, it being understood, that the rolls 1 and 2 are preferably conical as shown. The central roll is driven by means of the shaft 3 and the belt-pulley l mounted on said shaft. The central roll 1 is provided at its ends with spur gears 5 meshing with spur gears 6 on the ends of the rolls 2. The gears 6 mesh With circular racks 7 in the casing. The rolls 1 and 2 preferably consist of hard porcelain and the casing 8 is provided with a lining 9 which if the rolls 1 and 2 are conical is also conical and also consists of vhard porcelain.

The goods are fed to the rolls 1 and 2 by way of a hopper 1() and a Worm 11, the axis of which may be disposed vertically as shown in Fig. 1 or may, as shown in Fig. 2, be coincident with the shaft'3. A conical valve 12 which is vertically adjustable by actuation of a hand wheel 14 controlling the lever 13 regulates the delivery of the goods from the hopper 10 to the worm 11.

On the outer faces of the left-hand gears 6 are eccentrically mounted grinding discs 15 the end faces of which co-operate with a stationary annular grinding disc 16 having a close fit within the casing. The discs 15 depart from circular form, being in the present case of elliptical form,

The eccentricity and dimensions of the discs 15 which rotate with the gears 6 are such that the said discs 15 in their rotary motion alternately sweep past the point of engagement of the gears 6 with the gear 5 and the points of engagement of the gears 6 with the circular rack 7. The faces of the discs 15 adjacent to the gears 6 are formed with grooves 17 at the points of maximum eccentricity, the mearr distance of which grooves from the axes of rotation of the discs 15 corresponds about to the radius of the pitch circle of the spur gears 6 and which grooves communicate with holes 18 leading to the outer faces of the discs 15. It is thus ensured that the. goods pressed by the rolls 1, 2 through the points of engagement of the gears 6 with the gear 5 and the circular rack 7 will not exercise a binding or choking action at the points where the grinding discs 15 sweep past said points of engagement, but can pass through the holes 18 to the outer grinding and rubbing .faces of the discs 15. The stationary annulus 16 is provided as shown in Figs. 5 and 6 with tangential grooves 30 on each side, and its end face which is to the left in Fig. 1 contacts with an additional movable grinding annulus 19 which is fixed to the shaft 3 by means of a boss 2O so as to be longitudinally movable along the shaft 3 but rotatable with the vided on the face which is at the left in Fig..1 with a pocket-like cavity 21 which is found advantageous for effecting good distribution of the goods on the grinding faces between 16 and 19. This pocket 21 is somewhat displaced from the vertical in the direction of rotation of the disc 19.

By axial shift of the shaft 3 it is possible to adjust the intervals between the central roll 1 and the rolls 2. The shaft 3 is provided at the right-hand end with a throughslot a and abuts through the intermediary of a collar c against a powerful helical spring 22, the compression of which is adjustable by operation of a set screw 23. A cotter b penetrating the yslot limits the shift of the shaft 3 towards the right, it being under-V stood that Fig. 1 shows the rolls spaced at their furthest distanceapart, that is, the eX- treme right-hand position of the central roll. Engaging the left-hand end of the shaft 3 is a set-screw 24. Toreduce the spacing of the rolls, the shaft 3 can be shifted to the left by operation of the set-'screws 23 and 24. With this displacement the baseof `the slot a is spaced from the cotter b, and the shaft 3 is then subject only to the actionof the spring 22. The central roll'l is thus resiliently movable in axial direction which is desirable for compensating for unforeseen resistance. Also the pressure of the rotatable dlsc 19 against the stationary disc 16 is adjustable. To effect such adjustment there is rovided a screw-threaded bush which ars, preferably through the intermediary of a ball-bear-ing 26, against the boss 20, and by adjustment of which bush the boss together with the disc 12 can be shifted axially. If the disc 16 is so uided in the casing that it can shift in the ongitudinal direction of the latter but cannot rotate, then by adjustment of the screw-threaded bush 25 also the pressure between the disc 16 and the discs 15 can be varied. The discharge of the ground goods is effected at 27. In front of the rolls 1 and 2 is a distributing` chamber 28 to which the goods are fed by the worm 11. Due to the eculiar movement of the planetarily rotata. le elliptical grinding discs 15 there is effected a pumping action which continuously pumps forward the mass which has attained in the roll mill a sufficient fineness to pass between thediscs and which presses the goods through the'grinding discs located at the end of the mill. The entire grinding operation is effected positively from the feed worm up to the point of discharge. The elliptical discs 15 are provided on their end faces with crossing grooves 31 f Figs. 3 and 4) so that the sucking effect of these discs varies continuously and their surfaces wear and act uniformly.

In the position shown in Fig. 3 the sucking action is effected with regard to the upper discs on their right-hand side, while in the' position shown in Fig. 4, in which the limit of the throw is towards the centre, the suckin action is effected on the other side.

he set of grinding discs may be added to if desired by incorporating additional grinding discs as shown in Figs. 6 and 7.

I claim 1.- A grinding mill incorporatinga casing, an annular grinding disc located in said casing, a plurality of planetarily driven grinding discs the end faces of' which co-operate with said annular disc, grinding rolls connected with said planetarily driven grinding discs .and a central roll about which the first named rolls rotate and which is externally driven, intermeshing spur gears on the rolls to planetarily drive the outer rolls from' the central roll, the end faces of the spur gears at the exit ends of the planetary rolls carrying the movable discs.

2. A grinding mill incorporating a casing, an annular grinding disc located in said casing, a plurality of planetarily driven grinding discs the end faces of which co-operate with said annular disc, grinding rolls connected with said planetarily driven grinding discs and a central roll about which the first named rolls rotate, and which is externally driven, intermeshing spur gears on the rolls to planetarily drive the outer rolls from the central roll, the end faces of the spur gears at the exit ends of the planetary rolls carrying the movable discs, the movable discs being elliptical and of such dimensions or of such eccentricity that they alternately sweep past the points of engagement of the spur gears on the planetary rolls with the spur gear on the central roll, and the points of engagement of the first mentioned gears with a circular rack within the casing.

3. A mill such as claimed in claim 1, further characterized in that the faces of the movable'discs adjacent to the spur gears are provided at the points of maximum eccentricity with grooves the mean distance of which from the axes of rotation of the said discs is equal to about the radius of the pitch circle of the spur gears and which communicate with holes` leading to the outer faces of the discs.'

4. In a grinding mill, a' casing, a stationary grinding disk in said casing, other grinding disks mounted in said casing and of elliptical form and being facially presented to the adjacent face of the stationary grinding disk to coact therewith to grind material delivered between the faces of the disks, and means for imparting planetary motion to the elliptical grinding disks.

5. In a grinding mill, a casing, a conical grinding roll rotatably mounted therein, an annular grinding disk within the casing concentric to the axis of rotation of said roll, a lplurality of grinding disks mounted in the casing adjacent the ends of conical grinding rolls, andof elliptical form and presented facially tothe adjacent face of the first mentioned disc,l andadapted to cooperate with said first-mentioned disc, conical grindin rolls rotatable within the second mentione grinding disks and about the first mentioned roll( and means for imparting rotary motion to the first and second mentloned grinding rolls and ,to the sa'd elliptical grinding disks.

6. In a grinding mill, a casing; a conical grindingroll rotatably mounted therein, an annular grinding disk within the casing concentric to the axis of rotation of said roll,

' a plurality of grinding disks mounted in the from the casing as delivered from said disks.

casing .and of elliptical form and presented facially-to the adjacent face of the irst mentioned disks and cooperating therewith, conical grinding rolls rotatable with the second mentioned disks and about the irstmen tioned roll, and cooperable therewith, 'and on the ends of which said plurality of grinding ,disks are-mounted means, for imparting motion to the first and second mentioned grinding rolls and to the said elliptical grinding disks, means within the casing for feeding the material to be ground, to the rolls, at the ends thereof remote from thesaid grinding disks, and means for delivering the ground material 7. In a grinding mill, a casing, a conical grinding roll rotatably mounted therein, an

annular grinding ydisk within the casing concentric to the axis of rotation of said roll, a plurality of grinding disks mounted in the casing and of elliptical form and resented facially to the adjacent face of the rst mentioned disk and cooperating therewith, conical grinding rolls rotatable with the second mentioned grinding disks and about the first mentioned roll and cooperable therewith, the

' said plurality of disks being mounted adja- "cent the ends of said conical grinding-rolls, a

grinding disk rotatable with the first mentioned grinding roll and coacting, facially, with the other face of the annular grinding disk, and means for imparting rotary motion to the first and second mentioned grinding rolls and to the said elliptical grinding disks.

Intestimony whereof I have signed my name to this specification.

THEODOR BRAGARD.

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