US2159239A

US2159239A - Feeder for pulverulent materials

Info

Publication number: US2159239A
Application number: US214969A
Authority: US
Inventors: Vogel-Jorgensen Mikael
Original assignee: FLSmidth and Co AS
Current assignee: FLSmidth and Co AS
Priority date: 1937-06-22
Filing date: 1938-06-21
Publication date: 1939-05-23
Anticipated expiration: 1956-05-23

Description

y 3 M. VOGEL-JORGENSEN 2,159,239

FEEDER FOR PULVERULENT MATERIALS Filed June 21, 1958 2 Sheets-Sheet l ATTORNEYS y 1939- M. VOGEL-JORGENSEN 2,159,239

FEEDER FOR PULVERULENT MATERIALS Filed June 21, 1938' 2 sheets sheet 2 l N VE N TOR fll/kaei l ayel-firyensew ATTORNEYS Patented May 23, 1939 UNITED STATES PATENT OFFICE 2,159,239 FEEDER FOR PULVERULENT MATERIALS New Jersey Application June 21, 1938, Serial No. 214,969 In France June 22, 1937 9 Claims.

This invention relates to feeders for pulverulent material, such for example as cement raw material which must be fed in predetermined quantities to rotary kilns.

Pulverulent material tends to form lumps and cavities and thus is difiicult to feed in predetermined quantities. It can be brought into a fluidlike state by being mixed with compressed air and at the same time mechanically stirred, so that What may be called an emulsion of the material in air is formed.

One object of the present invention is to provide an apparatus which will feed desired quantities of such emulsified material. Another object is to measure out fixed quantities of such material at rates dependent upon those at which the material is to be used or consumed in, for example, a rotary kiln. Further objects will appear hereinafter.

The invention will best be understood by reference to the following description taken in conjunction with the drawings annexed hereto, which show the preferred form of apparatus according to the invention and in which:

Figure 1 is a diagrammatic elevation of a feeder, for supplying cement raw material to a rotary kiln through a nodulising device,

Figure 2 shows diagrammatically the feeder, the nodulising device and the rotary kiln,

a Figure 1 and Figures 4 and 5 show details to an enlarged scale.

, The apparatus is designed to feed cement raw materials in pulverulent form from a silo l to a rotary kiln 2 through a nodulising device 3. In such a kiln it is customary to regulate the output in accordance with the speed of rotation of the kiln and therefore it is desirable to feed the raw materials to the kiln at a rate depending upon that speed. The apparatus according to the invention enables this to be done.

The apparatus includes a reservoir 4 for pulverulent material and means -5 for extracting the .material from the, reservoir and feeding it through a hopper 6 to the nodulising device 3. The reservoir rests on an angle iron support 39. The material. drops from the silo i into a cylindricalv hopper l and is there brought into a fluidlike state by means of compressed air supplied through a pipe line 8 and nozzles 9. The material and air in the hopper l are mechanically stirred by a stirrer In similar to the one arranged in the bottom of the reservoir 4 and as hereinafter described. The stirrer ID is carried on a Figure 3 is a section on the line III-III of shaft II, mounted in bearings l2 carried by brackets l3 fixed to the hopper l. The material, having thus been mixed with air, flows down through a pipe 14 to the reservoir 4. In the reservoir 4 it is further mixed with compressed air supplied through a pipe line l5 branching ofi, like the line 8, from a common supply pipe line IS. The compressed air is supplied to the reservoir 4 through nozzles l1, and the material is there also mechanically stirred by a stirrer l8 carried by a shaft l9 mounted in bearings 20. The bearings are carried by brackets 2| fixed to the reservoir 4. The stirrer l8 consists, like the stirrer Ill, of four rods 35 parallel to the shaft I9 and kept in correct position in relation to each other by means of a number of rings 36. The rings have spokes 31 radiating from the boss 38 clamped together round the shaft Hi. The shafts II and H] are both driven by a motor not shown and are interconnected by a chain 22 which engages

chain wheels

23 and 24 mounted respectively on the shafts II and l9. 7

The extracting means 5 takes the form of scoops fixed to'a shaftvand adapted to penetrate into the reservoir below the level of the material therein and to extract therefrom at each penetration a volume of material which will be fixed so long as the level of the material in the reservoir is constant. Instead of such scoop means an endless chain of paddle buckets or any other device which, assuming a constant level of material, will charge itself with a volume of material dependent only on the speed at which it works may be used. In general such extracting means should move in a closed path and be adapted during each complete movement through the path, to extract a predetermined volume of material from the reservoir and to deliver that volume outside the reservoir.

The feeding device shown in the figures consists of two circular discs 25 arranged beside each other, between which two metallic bands 26 bent on a logarithmic spiral serve as Scoops; their arrangement will be seen from Figs. 1 and 3. To one of the discs is fixed a boss 29 through which the carrying shaft 30 is stuck. The shaft rests in the bearings 32, and the whole feeding device is kept in rotation by means 'of a geared motor 34 transmitting the motion through couplings 33. The shaft 30 is led in through the wall of the reservoir 4through a bushing 3| preventing the raw meal from getting out as dust at this point. From Fig. 1 appears that the feeding device for each half revolution takes up a certain quantity revolution carries up into the central hollow 1 11,

whence it is led out through the spout-shaped feeding device as long as it is desired it is necessary to provide means for maintaining the same surface level in the reservoir 4. For this purpose is placed in the reservoir 4 a float 49 consisting of a hollow metal box the shape of which is adapted to the-shape of the reservoir. The float 4|! is carried by an arm 4| pivotally mounted in a bracket 42 fixed on the outside of the reservoir 4. A counterweight 43 is adjustably secured to the arm 4 I -so that the depth to which the float 40 immerses itself in the fluid-like material can be adjusted as desired.

' On the top face ofthe float is fixed a fork 13 which grips and, by means of a bolt I4, is pivotally attached to a cylindrical member I5 serving as a nut for the threaded rod 44 so that said rod can be screwed more or less deep into the cylin drical member as desired. The rod 44 merges at the top in a slide valve 45 which can be moved up and down in the casing 46. This slide valve 45 controls the compressed air supply from the pipe line 41 so that either

pipe line

48 or 49 is under pressure.

Fig. 4 shows details of the slide valve, and it will be seen that the slide valvein the position shown allows the compressed air to pass from pipe line 41 to 49, whereas pipe line 49, through the bore 5|, communicates with the atmosphere. Inv case the level of material in the reservoir 4 had been higher, the buoyancy on the float would have caused the rod 44, which at thetop is fitted with a plate 52, to rise and overcome the pressure from the spring 53 which presses on the said plate 52 and is placed under a protecting cap 54, which further affords the requisite reaction against the spring pressure. In that case there would have been open passage from the line .41-49, whereas the line 48 through bores 59 would have been in communication with the atmosphere. The slide valve is, by means of the flange 55, fixed to the overside of the reservoir 4. Y

The counterweight .43 and the spring 53; which counteract each other, damp the movement of the float 40 adequately.

The

lines

48 and 49 lead to a compressed air motor 56 the details of which are shown. in Fig. 5. This motor comprises a piston 51 which can move in the cylinder I1 and the piston rod of which carries a gate 59. This can be moved in and out of the slit 60 in the pipe l4 and thus I open for or cut off the supply of materials through this pipe. In order to provide tightness for the dusting raw meal the pipe is at this place surrounded by a ring I6 which is likewise fitted with a slit allowing passage for the gate 59 but which is fitted with a felt seal or the like.

The compressed air motor 564s fixed to the underside of the cylindrical hopper I by means of a pin 62 with flange 54. The pin has a threaded journal stuck through a bore in a boss 6| on the end of one cylinder cover of the compressed air motor. YA nut is tightens boss 6| and pin 62 together.

As the float 49 moves up and down the slide valve '45 serves to put one or other of the

pipe lines

48 and 49 under pressure and thus to move the piston '51 towards the right or left respectively as shown in Fig. 1. terial in the reservoir becomes too high, air flows through the pipe line 49, and the gate 59 throttles the feed through the pipe I4 until the desired level is again attained in the reservoir. Alterations in the desired level may be effected not only by adjusting the counterweight 43 but also byalter-v ing the position of the slide valve 45 in relationto the float 40.

This can be done by removing temporarily the cap 54 and the spring 53 and then by means of a suitable tool turn round the plate 52 and thereby the slide valve 45 and the rod 44 a suitable number of revolutions, whereby the rod 44 will-get deeper into or be lifted higher up in the threaded bore of the cylindrical member I5 so that the float 40 will be raised or lowered respectively in relation to the level of material.- If any alteration according-to the indicated methods is made the individual quantities of material removed from the reservoir by each revolution of the feeding device 5 will also be altered.

g From physics is known that when two vessels with confined air under pressure are put into communication with each other the air from the vessel with the highest pressure, which is assumed to be kept confiant, will flow over into ;the other vessel until the pressure in the latter' vessel is equalto the pressure in the former. So long as the pressure in vessel No. l is considerably higher than the pressure in vessel No. 2 the air vention that the same air quantity is constantly supplied to vessels 4 and I per unit of time it must be seen that the difference between the pressures in pipes 8 and I5 (and thereby I5) and the pressure inside said vessels is above the critical pressure. As there is now inside the vessels 9. pressure which is slightly higher than 1 atm. it will, in pursuance of the foregoing, be understood that it is necessary that the pressure in the compressed air lines is a good 2 atms. By this arrangement is attained that the fluctuations in the quantities of air supplied are avoided. This is an important factor, because it thereby ensured that the specific weight of .the mixture of air and pulverulent material remains constant, which is favourable to the measuring accuracy.

As previously stated, the feeding device is driven by a gearedmotor 94. By means of any synchronizing device of known design this motor 34 can advantageously be coupled electrically to the shaft for the motor driving the rptar" kiln. Thereby is obtained that any alteration in the speed of the kiln will cause the speed of the feeding device to change correspondingly. From the foregoing it will be understood that the feedquantity of material from the reservoir for each If the level of ma- I revolution, and as it rotates at a speed which is in a given proportion to the kiln speed, material is supplied to the kiln in the desired quantities.

From the hopper 8 on the feeding device the measured raw meal drops through the pipe 65 down into the hopper 66 taking the raw meal into the nodulising device 3, which on the drawings is shown in the form of a nodulising drum fitted with live rings 61 supported on rollers 68 in bearings not shown. In the drum, which is kept in rotation by means not shown, the raw meal is transformed into nodules and it leaves the drum as such through the outlet 69, to pass down into the kiln smoke chamber I0, whence it by known devices is fed to the rotary kiln 2.

Only the upper end of the rotary kiln is shown with a single live ring and the corresponding supporting rollers 12.

In the plant shown on the drawings the materials pass, as mentioned, from the feeding device to the rotary kiln through a nodulising device. Such a device is required for certain raw materials, but is not necessary in all cases, and it is therefore not wanted to have the invention limited to arrangements comprising such nodulising device.

I claim:

1. In an apparatus for feeding pulverulent material at desired rates, in combination, a reservoir for pulverulent material, means for emulsifying with air material in said reservoir, means moving in a closed path for extracting material from said reservoir, said extracting means being adapted during each complete movement through said path to extract a predetermined volume of material from said reservoir and to deliver said volume outside said reservoir, and means for operating said extracting means at a rate proportional to the desired rate of feed.

2. In an apparatus for feeding pulverulent material at desired rates, in combination, a reservoir for pulverulent material, means for emulsifying with air material in said reservoir, means for maintaining at a desired level the emulsified material in said reservoir, means adapted to penetrate into said reservoir below the level of material therein and to extract therefrom. at each penetration a volume of material dependent upon the level of material therein and to deliver said volume outside said reservoir, and means for operating said extracting means at a rate proportional to the desired rate of feed.

3. In combination, a rotary kiln, a reservoir for pulverulent material, means for emulsifying with air material, in said reservoir, means moving in a closed path for extracting material from said reservoir, said extracting means being adapted during each complete movement through said path-to extract a predetermined volume of 4. In an apparatus for feeding pulverulent ma- Y terial at desired rates, in combination, a reservoir for pulverulent material, 'means for supplying material to said reservoir, means for emulsifying with air material in said reservoir, float means in said reservoir actuatedin accordance with the level of material therein, means operated by said float means for controlling the supply of material to said a reservoir to maintain constant the level therein, means for extracting material from said reservoir in individual quantities dependent upon the level of material therein and for delivering said quantities outside said reservoir, and means for operating said extracting means at a rate proportional to the desired rate of feed.

5. In combination with the elements claimed in claim 4, a pneumatic relay operatively arranged between said float means and said supplycontrolling means.

6. In combination with the elements claimed in claim 4, a counterweight connected to said float means, and means for adjusting said counterweight.

'7. In an apparatus for feeding pulverulent material at desired rates, in combination, a reservoir for pulverulent material, means for supplying material to said reservoir, means for emulsitying with air said material before delivery to 'said reservoir, means for maintaining said material in an air-emulsified state in said reservoir, means moving in a closed path for extracting material from said reservoir, said extracting means being adapted during each complete movement through said path to extract a predetermined volume of material from said reservoir and to deliver said volume outside said reservoir, and means for operating said extracting means at a rate proportional to the desired rate of feed.

8. In an apparatus for feeding pulverulent material at desired rates, in combination, a reservoir for pulverulent material, means for emulsifying with air material in said reservoir, means for maintaining at a desired level the emulsified material in said reservoir, rotary scoop means adapted to dip into the material in said reservoir and to extract material from said reservoir and to deliver said material outside said reservoir, and means for rotating said scoop means at a rate proportional to the desired rate of feed.

9. In an apparatus for feeding pulverulent material at desired rates, in combination, a reservoir for pulverulent material, means for supplying pulverulent material to said reservoir, means for controlling the rate at which material is supplied by said supply means, means for emulsifying with air material in said reservoir, float means in said reservoir actuated in accordance with the level of-material therein, relavmeans connecting said float means and said controlling means, scoop means adapted to dip into the material in said reservoir and to extract material therefrom and to deliver said material outside said reservoir, and means for operating said scoop means at a rate proportional to the desired rate of feed.

MIKAEL 'VOGEL-JORGENBEN.