US3343800A

US3343800A - Crushing and drying apparatus

Info

Publication number: US3343800A
Application number: US445014A
Authority: US
Inventors: Rasmussen Frits
Original assignee: FLSmidth and Co AS
Current assignee: FLSmidth and Co AS
Priority date: 1964-04-29
Filing date: 1965-04-02
Publication date: 1967-09-26
Anticipated expiration: 1984-09-26
Also published as: NO118641B; FI41334B; SE313484B; ES312297A1; DE1276424B; AT268023B; GB992483A; DE1276424C2

Description

Se t. 26, 1967 F. RASMUSSEN 3,343,800 CRUSHING AND DRYING APPARATUS Filed April 2, 1965 1771 FIG 2 l'" I up.

INVENTOR.

ATTORNEYS l fs f rms? United States Patent 3,343,800 CRUSHHNG AND DRYING APPARATUS Frits Rasmussen, Copenhagen-Valby, Denmark, assignor to F. L. Smidth & Co., New York, N.Y., a corporation of Delaware Filed Apr. 2, 1965, Ser. No. 445,014 Claims priority, application Great Britain, Apr. 29, 1964, 17,813/64 Claims. (Cl. 241-47) ABSTRACT OF THE DISCLOSURE Apparatus for simultaneously crushing and drying moist material which includes means for introducing hot gas into a casing and crushing means inside the casing in the path of the hot gas. The crushing means is comprised of impactors for crushing the material against impact members and has a gas by-pass defined between a casing and the impact members which places the gas in heat exchange relationship with the impact members to dry any moist material which may accumulate on these members.

This invention relates to apparatus for crushing mineral material containing moisture as delivered, for example, from a quarry, and is concerned more particularly with a novel apparatus for both crushing and drying moist material. In the apparatus of the invention, the crushing operation is performed by impact action and the material is dried by hot gas passed through the zone where the crushing is being carried on. The construction of the apparatus is such that the efiiciency of the crushing means does not decrease as the rate of supply of the material to the apparatus increases and the apparatus is, accordingly, effective for the production of dried crushed material at a high output rate.

Impact crushers, in which the material is crushed by being struck by one or more rotary impactors and thrown against impact surfaces, are well known and hot gas has been introduced through the bottom of the casing of such a crusher to flow upwardly through the impact zone to dry the material. In a crusher of this type, the hot gas passes out through the top opening of the casing, through which the material is introduced, and carries with it entrained crushed material.

In such impact crushers with hot gas flow, as heretofore constructed, it has been found that the efiiciency of the apparatus is impaired, if the moist material is fed into the crusher casing at too rapid a rate. The reasons for this action are that, first, the hot gas is unable to penetrate a large mass of moist material undergoing crushing, so that the material in the interior of the mass is not properly dried, and, second, the moist material clings to the impact surfaces and forms coatings thereon which decrease the effectiveness of the impact action.

The present invention is, accordingly, directed to an apparatus for crushing and drying moist material, which overcomes the objections to the prior crushers above described and can be operated at a higher output rate without loss of elficiency. In the new apparatus, the impact members are so disposed within the crusher casing as to cooperate with the casing walls to form one or more by-passes, through which hot gas may travel from the bottom opening of the casing to the opening at the top. Part of the gas entering the casing flows up through the crushing zone to take part in the drying of the material therein, while the remainder of the gas flowing through the by-passes continually gives up heat to the impact members, so that they dry material in contact therewith and the formation of coatings on the members is avoided. At the top of the casing, the gas, which has passed through the crushing zone and has carried upwardly sufliciently fine crushed material is combined with the by-pass gas and the latter is effective to dry the entrained crushed material leaving the casing.

For a better understanding of the invention, reference may be made to the accompany drawing, in which:

FIG. 1 is a vertical sectional view on the line 11 of FIG. 2 of one form of the new crushing apparatus;

FIG. 2 is a vertical sectional view on the line 22 of FIG. 1; and

FIG. 3 is a view similar to FIG. 1 showing a different form of the apparatus.

The crushing apparatus shown in FIGS. 1 and 2 includes a metallic casing 10 which is reinforced by plates 11. The casing has a top opening 12, from which leads a duct 13, and an opening 14 at its bottom to which leads a duct 15.

A pair of impactors 16a, 16b are mounted in the lower part of the casing and each impactor comprises a shaft 17 having radial flanges 18 on which hammers 19 are pivotally mounted on rods 20. The impactors are rotated in the direction of the arrows (FIG. 1) and material struck by the hammers is thrown against impact members within the casing.

The members, against which material is thrown by the hammers of the impactor 16a, include

plates

21, 22 carried by a frame 23 pivotally mounted at 24 on opposite casing Walls. The frame 23 is held in proper position by a rod 25 which extends through an opening in the casing wall and is encircled by a spring 26 hearing at one end against a nut 27 on the end of the rod and at the other against the casing wall. Below the frame 23 carrying the

impact members

21, 22, there is mounted a third impact plate 28 carried by a frame 29 pivotally mounted on the casing wall. A bar 30 is attached to the frame 29 and extends through an opening in the casing wall, outside which it is attached to the outer end of a safety pin 31, the inner end of which is attached to the casing wall. The pin is so made that it will break and release the frame, when the pin is subjected to an excessive stress as a result of a heavy impact against the plate 28.

The

plates

21, 22, and 28 cooperate with the wall of the casing to define a by-pass 32 between the casing wall and the impactor 16a and the plates are so disposed in relation to the casing wall that the by-pass decreases in cross-sectional area in an upward direction. The crosssectional area of the by-pass may be further controlled by means of a throttle plate 33 mounted on the frame 23 between plate 21 and the casing wall.

The impactor 16b and the impact members associated therewith are of the same construction as the impactor 16:1 and its impactor members and the corresponding parts are designated by the same reference characters with the prime mark added. The impact plates 21', 22', and 2S cooperate with the casing wall to form a by-pass 32' between the wall and the impactor 16b and the bypass decreases in cross-sectional area in an upward direction. Flow through the by-pass 32' may be controlled by a throttle plate 33 mounted on the frame 23.

Grids 34 are disposed below the respective impactors 16a, 16b and the grids lie close to the path of travel of the outer ends of the

hammers

19, 19 of the impactors, so that material lodging upon a grid will be thrown by the hammers of the associated impactor toward the other.

In the operation of the crushing and drying apparatus shown in FIG. 1, the moist material to be crushed is introduced through the duct 14 and falls upon the impactors by which it is thrown against the impact members. The members lie outside the downward projection of the opening 13 at the top of the casing so that material to be crushed may drop between the plates 22, 22' without being intercepted thereby and the horizontal offsetting of

plates

21 and 22 and of

plates

21 and 22 allows material, which may have accidentally entered the by-passes, to fall to the impactors 16a, 16b. During the crushing action, hot gas is introduced into the casing through the duct and flows upward through the casing and out through the opening 12 and duct 13. Part of the hot gas passes up between the impact plates 28, 28' and thus through the crushing zone, while the remainder flows through the bypasses 32, 32' defined by the casing walls and the adjacent impact plates. The gas, which flows through the crushing zone, entrains crushed material and is joined at the top of the casing by the gas which has traveled through the by-passes. The by-pass gas heats the impact plates so that moist material tending to adhere thereto will be dried and will either not adhere or will be knocked free by material thrown against the plates by the impactors. Material not struck by the hammers but passing through the grids falls into the path of the gases flowing into the casing and is ordinarily entrained and carried through the casing either between the impactors or through the by-passes.

The gas with entrained material which travels through the duct 13 is passed to a separator in which the crushed dried material is separated from the gas. Material which passes between the impactors or through the grids and is not entrained by the hot gas, is collected and combined with the separated dried material discharged through the duct 14 or added to the material to be crushed.

The crushing apparatus shown in FIG. 3 includes a casing 35 having a top opening 36, from which leads a duct 37, and a bottom opening 38, to which leads a duct 39. A rotary impactor 16 of the same construction as the impactors 16a, 16b is mounted within the casing and it acts to throw material against impact members comprising horizontally spaced impact plates 4%, 41 mounted on a frame 42 pivotally mounted on the casing wall. The frame is held in position by a rod 43 attached to the frame and extending through the casing wall and the exposed part of the rod is encircled by a spring 44 bearing at one end against the casing wall and, at the other, against a nut 45 on the rod. The impact members also comprise a plate 46 mounted on a frame 47 pivotally mounted on the casing and held in place by a bar 48 attached to the frame and extending through an opening in the casing wall. The exposed part of the bar is attached to the outer end of a safety pin 49, the inner end of which is secured to the casing. The pin will break and release the frame if the latter is subjected to an excessive stress.

The

plates

40, 41, and 46 cooperate with the wall of the casing to form a by-pass 50 which decreases in crosssectional area in an upward direction. Gas flow through the by-pass may be controlled by a throttle plate 51 mounted on the frame 42.

Fixed impact members 52 are mounted on the opposite side of the impactor 16' from the

frames

42, 47 and the

plates

40, 41 and 46 carried thereby. The members 52 cooperate with the casing walls to form a bypass 53 which decreases in cross-sectional area in an upward direction. As in the construction shown in FIG. 1, the impact members above the impactor lie outside the downward projection of the opening 36 and thus do not interfere with the free fall of material introduced into the casing through the opening 36.

In the operation of the form of the crushing apparatus shown in FIG. 3, the moist material to be crushed is introduced into the casing through the opening 36 and falls between the fixed impact members 52 and the

plates

40 and 41 to the impactor 16. Hot gas enters the casing from the duct 39 through the opening 38 and part of the gas travels through the by-passes 5t 53, while the remainder passes upward through the crushing zone. Material reduced to the proper size is entrained in the gas passing between the

plates

40, 41, and 46 and the plates 52 and carried out of the casing through the opening 36. The hot gas traveling through the by-passes heats the impact members so that the moist material will not adhere to the surfaces of the members and thus reduce the efiiciency of the crushing operation.

I claim:

1. An apparatus for simultaneously crushing and drying moist material, comprising a casing having openings at its top and bottom, means for introducing hot gas into the casing through the bottom opening, means for introducing material to be crushed into the casing and for conducting gas and entrained crushed material from the casing through the top opening, and crushing means inside the casing in the path of gas flowing upwardly through the casing, the crushing means including impactors for crushing material against impact members and the impact members adjacent to but spaced from the casing side walls and co-operating therewith to define at least one by-pass open at its bottom to receive part of the hot gas introduced through the bottom opening of the apparatus with the gas flowing upwardly through the by-pass in heat exchange relationship with the impact members to dry material in contact therewith and the top of the by-pass opening adjacent the top opening of the apparatus so that gas from the bypass combines with the gas and entrained material to dry the entrained material.

2. The apparatus of claim 1, in which the impact members partly defining the bypass are spaced successively closer to the casing wall to decrease the cross-sectional area of the bypass toward the top opening of the casing.

3. The apparatus of claim 1, in which the impact members are disposed outside the downward projection of the boundary of the top opening of the casing.

4. The apparatus of claim 1, in which two of the impact members partly defining the bypass and disposed adjacent to the top opening are spaced horizontally for escape from the bypass of material entering the upper end of the bypass.

5. The apparatus of claim 1, in which means for regulating the flow of gas through the by-pass are mounted inside the casing.

6. The apparatus of claim 5, in which the regulating means comprise a throttle plate mounted on an impact member and reducing the cross-sectional area of the bypass.

7. The apparatus of claim 1, in which the impact members cooperate with opposite side walls of the casing to define a pair of by-passes with the crushing means between them.

8. The apparatus of claim 1, in which the crushing means include at least one impactor mounted for rotation inside the casing adjacent to the bottom opening and impact members on opposite sides of the impactor cooperating with opposite side walls of the casing to define by-passes for gas around the crushing means.

9. The apparatus of claim 7, in which a grid is disposed within the casing below the crushing means.

10. The apparatus of claim 8 in which the crushing means includes two impactors mounted for rotation on substantially parallel horizontal axes.

References Cited 5 1,027,964

UNITED STATES PATENTS 348,977

9/1896 'Bailly 24147 992483 4/1907 Du Pont 24165 X 385,600 6/1916 Coleman 241-47 X 1/1929 Wood 241-80X 6/1930 Lykken 241189 X 11/1949 Kessler 241-189 X FOREIGN PATENTS 10 WILLIAM W. DYER, JR., Primary Examiner.

R. I. ZLOTNIK, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,343,800 September 26, 1967 Frits Rasmussen It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, after line 12, insert 3,058,676 10/1962 Hermann -241-186 Signed and sealed this 24th day of September 1968.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer

Claims

1. AN APPARATUS FOR SIMULTANEOUSLY CRUSHING AND DRYING MOIST MATERIAL, COMPRISING A CASING HAVING OPENINGS AT ITS TOP AND BOTTOM, MEANS FOR INTRODUCING HOT GAS INTO THE CASING THROUGH THE BOTTOM OPENING, MEANS FOR INTRODUCING MATERIAL TO BE CRUSHED INTO THE CASING AND FOR CONDUCTING GAS AND ENTRAINED CRUSHED MATERIAL FROM THE CASING THROUGH THE TOP OPENING, AND CRUSHING MEANS INSIDE THE CASING IN THE PATH OF GAS FLOWING UPWARDLY THROUGH THE CASING, THE CRUSHING MEANS INCLUDING IMPACTORS FOR CRUSHING MATERIAL AGAINST IMPACT MEMBERS AND THE IMPACT MEMBERS ADJACENT TO BUT SPACED FROM THE CASING SIDE WALLS AND CO-OPERATING THEREWITH TO DEFINE AT LEAST ONE BY-PASS OPEN AT ITS BOTTOM TO RECEIVE PART OF THE HOT GAS INTRODUCED THROUGH THE BOTTOM OPENING OF THE APPARATUS WITH THE GAS FLOWING UPWARDLY THROUGH THE BY-PASS IN HEAT EXCHANGE RELATIONSHIP WITH THE IMPACT MEMBERS TO DRY MATERIAL IN CONTACT THEREWITH AND THE TOP OF THE BY-PASS OPENING ADJACENT THE TOP OPENING OF THE APPARATUS SO THAT GAS FROM THE BY-PASS COMBINES WITH THE GAS AND ENTRAINED MATERIAL TO DRY THE ENTRAINED MATERIAL.