US1559786A - Feed control for pulverizing mills - Google Patents

Description

Nov. 3,1925. 1,559,786

O. A. SAUER FEED CONTROL FOR PULVERIZING MILLS Filed Aug. 16. 1923 2 'Sheets-Shut L Nov. 3, 1925. 1,559,786

O` A. SAUER FEED CONTROL FOR PULVERIZING MILLS Filed Aug. 16, 1923 2 Sheets-Shut 2 Y ,YZ/nde fab/Oft Patented Nov. 3, 1925.

UNITED STATES PATENT oFElcE.

OTTO A. SAUER, OF SAN ANTONIO, TEXS, ASSIGNOR THREE-FOURTHS TO EUGENE D. NIMS, OF ST. LOUIS, MISSOURI.

FEED OONTROL FOR .PUL'VERIZING MILLS. l

Application filed 'August 16, 1923. Serial No. 657,796.

To all lwhom t may concern.'

Be it known that I, OTTO A. SAUER, a citizen of the United States of America, and a resident of San Antonio, county of Bexar, and State of Texas, have invented a new and useful Improvement in Feed Control for Pulverizing Mills, of which the following is a specification. i

This invention relates to feed control means for roller-mills wherein the pulverized product is removed'from the mill by an air current.

The main objects of this inventionJ are to provide improved mechanism for controlling the feeding of raw material to the mill; to provide improved mea-ns actuated by the condition of the air current for regulating said feeding mechanism; and to provide improved related means and mechanism of this kind whereby the feeding of raw material is automatically proportioned to the -capacity of the mill to elfect a satisfactory pulverization and removal ,of the material.

An illustrative embodiment of this in- I vention is shown in the accompanying drawings, in which:

Figure v1 is a vertical, sectional elevation of a special typeof pulverizing roller-mill showing an improved v feed control, constructed in accordance with this invention, applied thereto, the feed control being illustrated somewhat diagrammatically.

Figure 2 is a plan of the same.

Figure 3 is a detail view Afurther illustra-ting the manner in whiclrthe feed control functions. f t

One common form of pulverizing mill heretofore in use requires the constant services of an attendant to control the feedof material intothe mill so as to prevent choking at the crushing rollers. The present invention provides a roller mill which is entirely automatic in its operation so as lnot to require thev services of an attendant after the material has been placed in the hopper to be fed to the rolls. The device includes improved automatic mechanism for controlling the feed of material from the hopper to the rolls. This improved mechanism is actuated by an air motor controlled by changes in the static pressure of the air current within the mill, depending upon the amount of material located at the rolls. In construction, the mill is somewhat similar to a Ven- `turi tube in which thev grindingv chamber forms the reducing cone and the separating chamber forms the expanding cone, with the rollers located at the throat of the Venturi tube. The material in process tends to obstruct the passage of the air through the throat, thereby controlling the static pressure in the grinding chamber. static pressure in the grinding chamber is proportional lto the amount of material obstructing the throat.` If the mill is choked by an excess amount of material, the air pressure in the grinding chamber increases and the air motor is thereby actuated to close the inlet valvel of the feed chute until a sufficient amount of material passes through the rolls to materially reduce the air pressure within the grinding chamber.

In Athe specific4 embodiment herein illustrated,the improved feed control is shown asappliedto avertical pulverizing mill of The.v

the Raymond type, but it is also applicable to other types and makes of mills.

The mill comprises a housing 1 which pro-4 l vides-a grinding chamber 2 andan air'separating chamber 3 arranged' one above the other and communicating with each other.

The raw material enters through the openl ing 4 where'itis delivered to the grinder 5 and the pulverized linished product isv carried-by an air current up intothe separator able collector c. An air inlet pipe 7 connects with an annular conduit v7A surrounding the grinding chamber 2 and communicating with said conduit through ports 7b for distributing the incoming air in the grinding 3 and out through an outlet port6 to a suitsusl This pendulous mounting of the rollers 8 causes them to swing outwardly during the rotation of the member 11 sol as to bear` against a bull-ring 14 arranged on the adjacent inner wall of the housing 1. Rigidly mounted on the carriage 11 is a plurality of blades or plows 15 located in advance of each roller 8 and arranged to revolve with the carriage 11 and to lift the raw material in the grinding chamber to a lplane .where it is caught between the rollers 8 and bullring 14. l

Suitable air 'pumping mea-ns such as a blower B connects with the air inlet pipe 7 pulley 35 is arranged on shaft 32 for conso as to set up an air current through the nection with a source of power.

grinding and separating chambers for the The mill, and the feed .control therefor, purpose of forcing the pulverized product' as herein shown and described operate Subjl through the grinder 5 and discharging it stantiallyv in the following mannen' .e

into the collector C from which collector As the carriage 11 is rotated-the rollers the finished product is delivered to suitable swing out against and revolve around t e containers. It -is desirable Ato connect. the bull-ring 14. The vplows 15 throw the ma\ airoutlet of the collector to the blower B terial up between-the rollers 8 andthe bullil so that any of the dust escaping from the' ring 14 where 1t is pulverized by the grind- 75" collector is carried back to the mill and ing action of the rollers and bull-ring. The

again delivered to the collector. air current produced by the blower B forces rlv`he specific embodiment of the feed con# such of the fine material as is not too heavy trol herein shown comprises a chute 16\plp into the separating chamber 3 and out through which a iow of material is conough the port 6 and delivers it to the trolled by a pair of gates 17 and 18 opercollector C. The materialthat is too heavy ated respectively by an eccentric and crank to be removed by the air current falls back mechanism 19 and a motor device 20. in the grinding chamber 2 and is re-ground.

rIhe chute 16 is suitably arranged withlv vAs the mill operates the eccentric 21, actrespect to the mill and has its lower end coning through the rod 23 and arm 24, shaft -25 'nected to the material inlet 4 and its upper and arm 26, reciprocates the gate 17 causend connected to a bin or other suitable ing it to be intermittently opened and closed Above that the chute may be partially open arranged for that purpose. The gate 18 is terial to pass to the material opening 4. If.

source of supply. Inasmuch as there is an for releasing and checking the flow ofraw air current throughthe mill thechute is material through vthe chute 16 toward the substantially air tight up to the gate 18. gate 18. y

j -The gate 18 is normally arranged so as to on the top side if desir d. be raised from the bottom of the chute a The gate 17 is slidably mounted trans-v predetermined distance such as will allow versely of the chute insuitable guideways for a predetermined quantity of raw masimilarlyv mounted in the chute between for an reason an excessive amount of the the gate 17 and the material inlet 4 of the pulverized material in the grinder 5 and in mill. the Separating chamber -3 tends to retard The eccentric and crank mechanism 19 the free movement of the air current and dust for operating the gate 17 includes an eccentherethrough, there is a building up of tric 21 journaled on a shaft-22 and having Y pressure in the grin'dingchamber 2 and inl a rod 23 connecting it with an arm 24l which the annular conduit 7A. This increased bellows of diaphragm construction arranged mill.

is attached to a shaft 25 journaled on chute pressure reacts on the diaphragm motor de- 16 and connected to the gate 17 by an arm vice 20 so a's to cause it to shift the gate 18 26. The connection of the rod 23 and arm to reduce the size of the opening between 24 is made adjustable so. as to vary the aeit and the chute, thus decreasing the supply tion of the eccentric-crank mechanism 19 0f raw material fed t0 the mill. AS 4S0011 on the gate. During the operation of the as the accumulation of pulverized material mill, the gate 17 is reciprocated continuously in the mill is eliminated and a normal flow so as to serve as an agitator thereby faeiliof air current is re-'established the diatating the flow of material through the phragm motor 20 reacts so as to produce a chute. j further opening of the gate 18 and an in- The motor device 2O is a suitable form of crease of the supply l0f MW material t0 the on the side of the housing 1 adjacent to the It will thus be seen that through the me- 'grinding chamber 2 se as t0 communicate dium of the motor device 20 and its ine- I with the annular air conduit 7^. A `rod 27 Challlcal Connections t0* the gate-18 the sul" and a rod 28, connected together by a bellply 0f IaW .material iS automatically PrO- crank lever 29, communicate the movements portoned t0 the capacity of the mill to ul- 0f the diaphragm motor device 20 te the verize the same and have the pulverized gate 18 through the medium 0f a, lever 30 product removed by the air current. Such mounted on the chute 16. A turnbuekle 31 a feed control .results in a more steady and maybe arranged on rod 28 for the purpose uniform operation of a mill and a more a suitable belt and pulley connection 34. 'A altered o1, omitted without'dep-arting from of properl adjusting .the gate 18 to the -uniform andabundant yield of the finished action of t e motor device 20. product.

The driving mechanism for themill and Although but one specific embodiment of -the feed control comprises a driving shaft this invention has been herein shown and 32 which.4 is connected to; the shaft 12 by described, it will be understood that certain gear and pinion 33 and to the sha-ft 22 by details of the .construction shown may be the spirit 'of this invention as Idefined by the following claims.

I claim: p

l. In a pulverizing machine, grinding means, a feed control, comprising a chute, a pair of gates arranged to control the flow of material along said chute, mechanism connected to be actuated by the means for constantly reciprocating one of said gates 4for intermittently checking and releasing the flow of material along said chute, a motor Vdevice connected with the machine and adapted to be actuated by changes created therein by variations in the vo-lume of the finished product, and a mechanical connection between said motor `device and the other gate, whereby said other gate is shifted by said motor device for regulating the quantity of material delivered to the of material along said chute, vand a diaphragm motor device connected with said machine and adapted to be actuated by changes in the air current created by variations in the volume of finished product, said motor device being connected to the other gate, whereby said other gate is shifted by said motor device for regulating the quantity of material delivered to the machine.

3. A pulverizing mill comprising a grinding chamber, an air separating chamber above said grinding chamber and communieating therewith through a restricted throat, grinding means located in said throat, air circulating means for normally forcing a current of air upwardly through said chambers, means controlling the feed of material to said chambers, and an air motor communicating with said Grinding chamber below said throat and a apted to be actua-ted by an increase of air pressure in said grinding chamber through the choking of said throat by an excess amount of material, said air motor being arranged to actuate said feed control means for reducing the feed of material when said throat is choked.

Signed at San Anto-n10 this 9th day of August, 1923.

. OTTO A. SAUER.

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