US2084976A - Speed controller for clinker coolers - Google Patents

Description

June 22, 1937. B. H. PUERNER SPEED CONTROLLER FOR CLINKER COOLERS Filed Aug. 30, 1935 mm/L?,

Patented June 2v2, 1937 UNITED STATES PATENT ori-fics SPEED CONTROLLER FOR CLINKR COOLERS Application August 30, 1933, Serial No. 687,456

16 Claims.

This invention relates generally to apparatus for cooling heated material and particularly to control mechanism for regulating the operation of materiel cooling apparatus.`

5 In cooling apparatus of the type employing a grate for supporting a bed of material to be cooled and having a fan to blow air through the material, it is necessary that the bed of material be maintained of substantially uniform thickness to insure uniform distribution of air to cool the material efiiciently. Ordinarily, the thickness of the bed of material is regulated by adjusting the speed at which the material is advanced over the grate. This is usually done by manipulating l5 a manually operated speed controlling device in accordance with the. observed thickness of the material bed, although it has been proposed to eiect automatic regulation of the speed of the material by mechanism 'responsive to the position of a flap or spreader bar arranged to engage the surface of the material.

A general object of the present invention is to provide automatic means for regulating the thickness of a bed of material advancing over a perforated grate;

Another oject of the invention is to provide In ,chanism for automatically regulating the thickness. of a bed of material advancing over a grate by controlling the speed of advance of the material in accordance with the pressure required to force air through the bed of material.

A further object of the invention is to provide apparatus for cooling heated material which will operate continuously and automatically to cool the material eiciently.

A further object of the invention is to provide material cooling equipment, of the type wherein the material is advanced over a grate through which cooling airis forced, and having control mechanism responsive to the pressure necessary to force air through the material on the grate and operative to regulate the speed of advance of the material to maintain the material bed of uniform thickness in order that the cooling air may penetrate all parts of the material bed uniformly.

In accordance with the present'invention the thickness of a bed of material advancing over a grate is regulated by controlling the speed of advance of the material in accordance with the resistance oiered by the bed of material to the air forced through it to cool it.

The foregoing and other objects of the invention may be achieved by apparatus constructed in accordance with the principle of the control mechanism described in this spccication as a practical embodiment of the invention and shown in conjunction with material cooling apparatus in the accompanying drawing, in which:

Fig. 1 is a View, partly in side elevation and partly in longitudinal section, of material cooling 5 apparatus having a control system embodying v the invention;

Fig. 2 is a view in transverse section taken on the plane represented by the line II-II in Fig. 1; and 10 Fig. 3 is a schematic diagram of the apparatus for controlling the operation ol the cooling mechanism in accordance with the invention.

The particular cooling mechanism illustrated is for cooling hot clinker or like material and com- 15 prises, in general, a shaking conveyor l arranged to receive the material to be cooled from. the discharge end of a rotary kiln 2 and having associated therewith a fan 3 for blowing cooling air through the material on the conveyor. The ma- 20 terial to be cooled is supported Within the conveyor upon a grate 4 constructed of round bars arranged longitudinally and spaced from each other to provide narrow openings permitting cooling air to pass upward through the grate and the 2 bed of material supported upon it. The grate 4 constitutes the bottom of a trough-like structure having vertical side walls 5 for confining the material being cooled. In order that air pressure may be established beneath the grate 4 to 30 force cooling air upwardly through the bed of material, the grate and the cooperating side Walls are carried within and supported by a closed housing 6. The housing 6 is, in turn, supported upon a plurality of leaf springs l arranged along 35 each side thereof and disposed'on end in such manner that the entire structure may be reciprocated longitudinally by deecting the springs to advance the material being cooled along the grate 4. The necessary reciprocating motion is given 40 the conveyor I by a connecting rod 8 connected thereto through buier springs 9 and operated by an eccentric I0 on an eccentric shaft Il. The eccentric shaft ll is driven by a motor I2 by means of a suitable driving connection I3. The 45 hot clinker discharged from the kiln 2 on to the grate 4 is distributed over the grate by the reciprocating motion thereof and is advanced along the grate in the direction away from the kiln and discharged from the grate into a conveyor i4. 50

Cooling air from the fan 3 is forced into the housing E througha suitable ilexible connection l5, which permits movement of the housing relative to the fan, and the air passes upward through the grate 4 and the material thereon being cooled. 55

The air, after passing through the material, is collected in a stationary air chamber I6 arranged abovethe conveyor I and slidably connected with it by air sealing means I'I. From the chamber I6 a portion of the heated air passes upwardly through the kiln hood 48 into the kiln 2 to serve as combustion air for fuel inthe kiln. Other portions of the heated air may be utilized for other purposes orwasted through a stack I8 as more .fully described in the copending application of Ray C. Newhouse, Serial No. 629,769, led August 22, 1932; which vmatured into Patent 2,055,940 0n September 29, 1936.

As the discharge of material from the kiln 2 is not entirely uniform in quantity, the bed of material on the grate 4 may vary in thickness from time to time in accordance with variations in the rate of discharge. If the rate of discharge from the kiln becomes greater than normal, a portion of the bed of material will be formed thicker than normal. Consequently the cooling air 'passing through it will meet `with greater resistance and the amount of air passing through the material will not be sufficient to cool it properly. Should the discharge from the kiln become advance of the material on the grate 4. .Ordinarily, according to the practice prior to the present invention, the controller I9 is manipulated b-y an operator in accordancewith his observation of the bed of material on the grate.

. However, such observations are usually not `sui?- ciently accurate nor consistently made to insure satisfactory regulation of the speed o-f the conveyor to maintain uniformi thickness of the bed of material and ecient cooling thereof.

In the operation of the cooling mechanism in accordance with the present invention, the bed of material being cooled is maintained of uniform thickness automatically, This is' accomplished by regulating the speed of therconveyor automatically by a control system which functions in respense to changes in the air pressure necessary to force the cooling air through the bed of material, the pressure being dependent upon the thickness of th'e bed of material.

When an excessive amount ofmaterial is Vdischarged from the kiln on to the grate, the resistanc/e to the i-loW of air upward through the material will bevincreased and consequently the pressure of the air within the housing 6 will rise.

The pressure Within the housing 6 is communi cated through a tube 20, having a exible connection 2l, to a pressure responsive device 22 which is connected to actuate the controller I9, causing it to increase the speed of the motor I2. When the speed of the motor i2 and of the conveyor i is thus increased, the material on the grate 4 will be advanced awa,r from the kiln 2 at an increased rate of speed and consequently the excess material deposited from the kiln will be spread over a larger area of the grate and will be distributed to form a hed'of uniform thickness. When the excess material has been so distributed, the air pressure within the housing 6 will return K position. This will result in a drop in pressure within the housing 6 which will cause the pressure responsive device 22 to reduce the speed of the motor and the speed of advance of the material. The motor will continue to operate at low speed until suilicient additional material has' been discharged from the kiln to increase the thickness of the bed on the end ofthe grate to normal, whereupon the motor will resume its normal speed. I

Themotor control system for regulating the rate of ladvance of the material on the grate 4 in accordance with the pressure necessary to force air through the material is shown diagrammatically in Fig. 3. Electric energy for operating the motor I2 is drawn from one line conductor LI through a conductor 23, one side of a disconnect switch 24 and a conductor 25 to the armature of the motor, thence through a conductor 26, the other side of the switch 24 and a conductor 21 to another line conductor L2. Current for energizing a field winding 28 ,of the motor I2 is taken from the line conductor LI through the conductor 25 by a conductor 29 to a manually operated arm 30 and a resistance winding 3I of the control rheostat I9, thence by a conductor 32 to the field winding 28 and a conductor 33 to the conductor 26 through which it passes to switch 24 and conductor21 to line conductor The pressure responsive control device 22 for automatically regulating the speed of the motor 2| comprises a plurality of mercury tube switches 34 arranged upon a common rocking shaft 35, Each of the mercury switches 34 is connected by suitable conductors 36 in shunt relation to a portion of the resistance element 3| of the field rheostat I9. The switches 34 are so arranged in angular relation on the shaft 35 that they will be closed successively to progressively shunt out sections of the resistance element 3l when the shaft is turned in the clockwise direction. The control apparatus is so adjusted that when the pressure within the housingv 6 is normal, half of the switches 34 are closed and the other half are open.

Upon the pressure within the housing 6 becoming greater than normal, the increased pressure is communicated through the pipe 20 to the pressure responsive device 22 where it acts upon a diaphragm 37 to force a piston rod 38 upwardly. The rod 38 is pivotally connected to one end of a pivotally supported scale beam 36 which is restrained in movement by a balancing spring 40 attached to its other end. The scale beam 33 is connected by a rod 4I to an arm 42 onthe rocking shaft 35 in such manner that when the rod 38 is moved upwardly by excessive pressure in the housing 6, the shaft 35 is turned counterclockwise, opening one or more of the normally closed switches 3i and thus increasing the amount of resistance in the circuit through the control rheostat I 9. This' results in increasing the speed of the motor i2 to thereby increase the rate of advance of the material on the grate, thus reducing the thickness of the material bed.

When the bed ofmaterial on the grate becomes too thin and the pressure Within the housing 6 falls below normal, the diaphragm 3l and rod 38 are moved downwardly by the balancing spring 5 40 and the shaft 35 is turned clockwise to close one or more of the switches 34 to shunt out additional sections of the resistance 3| thus reducing the speed of the motor I2 and retarding the maf terial until the bed on the grate has been built up to the desired thickness.

The pressure at which the motor I2 will oper ate at normal speed may be regulated by adjusting the tension of the balancing spring 40 by' means of an adjusting screw 43 and by'adjustlng the position of a slidable counterweight 44 on the scale beam 39. The pressure at which each suecessive change of speed of the motor I2 takes place may be regulated by adjusting the position of each mercury tube switch 34 angularly upon the shaft 35. The amount of speed change effected by the closing or opening of each switch 34 may be regulated by adjusting the positions at which the conductors 36 are connected to the resistance element 3l to change the amount of the resistance element shunted by each switch.

The particular material cooling mechanism and the control apparatus associated therewith that have been described in this specification as an illustrative example of a practical embodiment of the invention may be modied as to the particular structure utilized without departing from the spirit and scope of the invention as defined in the subjoined claims.

It is claimedpand desired to secure by Letters 35.Patent:

1. A clinker cooler comprising a grate arranged to progressively advance a bed of hot clinker, means arranged to force cooling air through the bed of clinker on the grate, and means responsive to the resistance of the bed of clinker to the flow of cooling air and arranged to regulate the rate of advance of the clinker bed in accordance therewith to maintain it of substantially uniform depth.

2. The combination with a conveyor arranged to advance a porous bed of material and means arranged to force air through said advancing bed of material, of means responsive to change in pressure of the air being forced through the material and connected to regulate the rate of advance of the materialin response thereto to maintain a substantially constant depth of material on said conveyor.

3. A control system for a conveyor arranged to advance a bed of porous material over an air draft, comprising means responsive to the back pressure of the air passing through the material and connected to regulate the speed of the conveyor in accordance therewith to maintain the advancing bed of material of substantially uniform depth.

4. A clinker cooler comprising a shaking conveyor for supporting a bed of clinker being cooled, means for driving the shaking conveyor to advance the bed of clinker, means for forcing air under pressure through the bed of clinker to cool it, and means responsive to the pressure required to force the air through theA clinker bed forregulatirg the speed of the conveyor driving means in accordance therewith to maintain the clinker bed of substantially constant thickness.

5. Apparatus for the manufacture and treatment of cement clinker, comprising a kiln wherein cement clinker is formed, a conveyor disposed to receive the clinker discharged from said kiln and to advance it in the form of a thin bed, means arranged to force air through the bed cf clinker to cool it, and means responsive to the pressure required to force the air through said bed for regulating the speed of said conveyor in accordance therewith to maintain said bed of yuniform thickness.

6. In a cement mill, a rotary kiln arranged to discharge hot clinker, a perforated conveyor disposed to receive said clinker and to advance it in a relatively thin bed, a fan arranged to force air through said bed of clinker to cool it, and means responsive to the pressure necessary to force air through the clinker bed for controlling the speed of the conveyor in accordance therewith to maintain a substantially constant thickness of clinker on said conveyor.

'7. The combination with apparatus arranged to deliver loose material, of a perforated conveyorI disposed to receive said material and to advance it in the form of a relatively thin bed, means for blowing air through said bed of material, and control apparatus responsive to the pressure of said air and connected to so regulate the speed of said conveyor in accordance therewith as to maintain the bed of material of substantially constant depth. p

8. A control system for a conveyor adapted to convey material, comprising means for forcing air through the material on said conveyor and means responsive to the pressure of said air for regulatingthe speed of the conveyor.

9. Material conveying apparatus comprising a grate conveyor arranged to advance material in a loosely packed bed, means for forcing air through said grate and said bed of material, and means responsive to the pressure of said air arranged to control the speed of said conveyor in accordance therewith for the purpose of regulating the depth of said bed of material.

10. Control apparatus for a conveyor arranged to advance a bed of porous material over a blast of air, comprising means responsive to the resistance of said bed of material to the ow of air therethrough and connected to regulate the speed of advance of said material on said conveyor to maintain said bed of substantially uniform thickness.

11. The combination with a conveyor arranged to advance a bed of porous material, means to drive said conveyor and means to force air through the bed of material, of control apparatus including means responsive to the air pressure required to forceair through said bed of material and means controlled by said pressure responsive means for regulating the speed of said conveyor driving means.

12.. In a control system for material treating apparatus, the combination with means disposed to support a bed of material being treated and means arranged to force fluid through said bed of material, of means responsive to the resistance of said bed ofy material to the passage of said :duid therethrough, and means controlled by said resistance responsive means for regulating the thickness of said bed of material.

13. In a system for applying fluid to loose material, means adapted to form said material into a pervious bed and to increase and decrease the perviousness of said bed, a uid chamber at one side of said bed, means adapted to pass a current of said fluid through said chamber and bed, and pressure responsive control apparatus for said bed forming means, in communication with said chamber and operable to increase the pervioussov ness of said bed in response to a decrease of ow, of said uid through said bed, and to decrease the perviousness of said bed in response to an increase of flow of said fluid through said bed.

14. In a system for applying fluid to loose material, means adapted to form said material into a pervious bed and to increase and decrease the perviousness of said bed, a iluid chamberat one side of said bed, means adapted to pass a current of said fluid through said chamber and bed,

control apparatus for said bed forming means, operable to increase and decrease the perviousness of said bed, and 'uid operated actuating means for said control apparatus, in communication with said fluid chamber and operable to increase the perviousness of said bed in response to a decrease of ow of said uid through said bed and to decrease theperviousness of said bed in response to an increase of ow of said uid therethrough.

15. Apparatus for the manufacture and treatment of cement clinker, comprising a rotary kiln wherein cement clinker is formed, a conveyor arranged to receive and advance the clinker discharged from said kiln, control apparatus for said conveyor; operable to increase and decrease the; speed of advance of the bed of clinker on said conveyor, means includingv a fan for passing an air draft through said bed of clinker, and pneumatic actuating means for said control apparatus, in communication with said fan and operableto increase the speed of advance of said bed in response to a decrease of ow of air through said bed, and to decrease the speed of advance .of said bed in response to any increase of i'low of air through said bed.

16. In a system for applying fluid to loose material, means adapted to form said material into- BERTRAM H. PUERNER.

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