US2946574A - Installation for making briquettes - Google Patents

Description

July 26, 1960 P. MUNDERICH INSTALLATION FOR MAKING BRIQUETTES Filed Aug. 28, 1958 United States Patent Office INSTALLATION FOR MAKING BRIQUETTES Paul Munderich, Ro'thenberg'eu, near Gelnhausen, Germany, assiguor to Wibau Westdeutsche Indus'trieuml 'Strassenbau-Maschinen-Gesellschaft m.b.H., Rothenberg, near Gelnliausen, Germany, a German company Filed Aug. 28, 1958, Ser. Nb. 757,882 Claimspriority, application Germany Aug. 30, 1957- necessarily leads to a demand for the reduction of binder requirement, since in view of the generally .good organisation of briquette factories, this offers the only chance of effectively reducing the costs.

Most briquette factories operate on the so-called ground pitch kneading process. in this process, the moisture content of the fine coal from the washery is reduced from about to just 1% in suitable special dn'ers with a drier outlet temperature of 90-100 C. The coal thus prepared is now passed by means of a conveyor to the dry coal bunker, whence it is taken by means of a proportioning conveyor to the feed worm conveyor. The hard pitch is broken manually in the pitch storage bunkers, is crushed to the required size (about 1 mm.) in an edge runner mill and carried by a conveyor to the ground pitch bunker. It is thence removed by means of a primitive proportioning device and passed to the feed screw, where it is broughttogether with-the dried fine coal. Dried coal and ground pitch are now passed via a mixing conveyor worm to the feed conveyor and thence via a central distributor to the individual steam kneading machines. I

In the steam kneading machine, due to the kneading process and the steam supplied, which assists the liquefaction of the ground pitch and facilitates the increase in the moisture content to the degree required for subsequent pressing, i.e. 24%, the actual conversion and preparation of the mixture of fine coal and ground pitch to form a pressable briquetting material now takes place. After passing through the kneading machine, the finished briquetting material generally passes directly to the feed 'head of the briquetting press.

Apart from the advantage of perfect continuity, a

'critical analysis of this process clearly shows serious disof the ground-pitch grains and their subsequent envelop- .ing by very fine coal dust necessarily takes place (formation of pockets oversaturated with binder).

Patented July 26, 1960 The impossibility of producing a really intimate mixture of coal and ground pitch thus also results-in a nonis rather reinforced, due to the so-called blotting paper effect, in which binder is removed from the coarser grain fraction by the very finest grains. This fact is responsible for considerable scatter in the strength values of the pressed briquettes, resulting in'necessary additional overproportioning of the required binder amount.

(0) Unequal moisture distribution within the briquette material. The'stream of materialtravelling through the kneading machine is in itself loosened'only slightly-er not at all, so that only a small part of thesurface of the briquetting material is exposed to "the action of steam (steam is introduced by means of nozzles above the stream of material). This inequality is also responsible for scatter in the strength values of the briquettes and leads to overproportioning of binder.

(d) The necessary grinding process involves the use of relatively hard sorts of binder, which subsequently obstructs the required spreading of thin films of binder on'the individual grain surfaces.

(e) Labour requirement for the preparationof the hard pitch, associated with the health hazards :for the pitch workers (pitch cancer).

(1) Machine requirement for the preparation of the hard pitch (grinding by edge runner mill).

' (g) Unacceptable outlay from the machinery :point of view makes it difiicult to meet the requirement for simultaneous production of different qualities of briquettes. If some-of the briquettes have to be of a panticularly highgrade quality, for example for export and overseas despatch, the entire installation has to be operated "with this adjustment.

The object of the present invention is to provide a fully automatic charge-mixing installation for'the manufacture of a briquet-ting material which is pressable immediately after'leaving the mixer and which obviates the aforesaid disadvantages.

The installation according to the invention has a device for weighing out the loose briquettin'g material in predetermined charge quantities and for feeding 'saidmaterial, devices for the simultaneous spraying of predetermined quantities of liquid binder and steam to the briquetting'material in the mixer, a device for discharging the pressable briquetting material from the mixer, and control means for automatically controlling said clevices according to a predetermined programme and for regulating the time sequence of the charges.

The drawing shows diagrammatically a constructional example of a charge-mixing installation according to the invention.

At a is shown a conveyor belt, for example a so cal-le'd Redler belt for the loose or bulk material (fine coal), which is driven by a motor a. In the discharge region a of the conveyor belt is a collecting shaft b, the outlet of which is provided with a flap 0. For opening-the outlet of the collecting shaft b, the flap c'can be swung from the closure position shown in the clockwise direction into the position shown in dotted lines under the action of a control cylinder y; operated by compressed air. The cylinder y is controlled by an electromagnetically operated valve x in a manner to be described more fully hereinafter.

Below the outlet of the collecting shaft b is a weighing container e, which is coupled to a weighing mechanism, not shown, and the outlet of which is controlled by a shutter e. Said shutter e can be moved underthe action of a control cylinder y operating on compressed air, from the closed position shown to an open position operated valve x indicated by dotted lines. The control cylinder y; is controlled by an electromagnetically operated valve x The weighing container or its weighing mechanism is operatively connected to a weight indicator g having a circular scale. The indicator g has at the origin of the circular scale a zero mark g, a moving pointer g and a preset pointer g", which pointers are formed as electrical contacts. When the two pointers cover one another, an electrical circuit is closed, the purpose of which will be described later.

Below the outlet of the weighing container e is a mixer 1 which, as shown, is preferably constructed as a high capacity double shaft mixer. In the region of the inlet from the weighing container, spraying nozzles are provided in the mixer f for the liquid hinder, the spraying range of which is indicated and which are connected by 'a pipeline p to a feed pump hr The feed pump it is driven by a motor i by means of an electromagnetic clutch k and draws binder from a tank 1 via a pipeline in and a flowrneter n, which is connected to a flow quantity indicator 0. The indicator has a circular scale, co-operating with a moving pointer 0' and a preset pointer 0". The two pointers are formed as electrical contacts and close an electrical circuit when they cover one another.

In the upper part of the mixer f steam injection nozzles s are provided, which are supplied with steam from a pipeline s, controlled by means of an electromagnetically operated shut-01f valve r. Preceding the valve r is a pressure regulating device q. The range of action of the jets from the nozzles s is indicated in the drawing.

The outlet of the mixer f situated in the container bottom is closable by a rotary slide f adapted to be operatedby a compressed air control cylinder y The cylinder y is controlled by means of an electromagnetically Underneath the rotary slide 1" is an intermediate container u, from which the mixed material is fed by a worm conveyor v directly to the briquetting press w.

For operating the described members of the installation, according to the embodiment shown, purely electrical control means are provided by way of example.

' A hand switch, not shown, serves for the initial control of the electromagnetic valve x the coil of which is also electrically connected to the moving pointer g or the preset pointer g". This arrangement is such that the magnet valve can be opened when the pointers g and g" do not cover one another, but is closed by the electrical pulse imparted when the pointers cover one another.

In the end regions of the opening and closing movements, respectively, of the flap c of the collecting shaft b are end switches 21 and Z2, the switch z being operated by'the opened flap and the switch Z2 by the closed flap. The switches Z1 and Z are connected to the circuit of the driving motor d of the conveyor belt a in such a manner that the switch 2 operated on opening of the 'fiap 0, starts the motor d, while the switch Z operated on closing of the flap 0, stops said motor.

A hand switch, not shown, is provided for the initial control of the electromagnetic valve x electrically to the indicator g in such a manner that the valve closes when the moving pointer g covers the zero .p'ointer g In the end region of the closing movement of the shutter e of the weighing container 2 is a switch 2 which is operated by the movement of the shutter and which is operatively connected to the electromagnetic valve x in such a manner that the pulse imparted by the is also operatively connected to the indicator 0 in such In addition, the electromagnetic valve x is operatively connected a manner that when the moving pointer 0' covers the preset pointer a", the power transmission through the clutch k is interrupted.

A hand switch, not shown, is provided for the initial control of the clutch k and at the same time serves for the initial control of the steam' clectromagnetic valve r. The electromagnetic valve r in its turn is operatively connected to the indicator 0 in such a manner that when the moving pointer 0 covers the preset pointer 0", the valve r is closed.

The indicator 0 is also electrically operatively connected to the electromagnetic valve 2: in such a manner that when the moving pointer 0 covers the preset pointer 0", a pulse is imparted for the opening of the electromagnet valve x The operation of the indicator 0 is furthermore subjected to a time-adjustable time switch I, which is started by the pulse on coincidence of the pointers 0" and 0'. The time switch t has a preset pointer t and a moving pointer t, which are formed as electrical contacts and to which electrical leads are connected. These leads, which when the preset pointer t is covered by the moving pointer t, are connected together, provide an electrical operative connection between the electromagnetic valve x and the time switch 1, such that the valve is closed when the moving pointer 2' covers the preset pointer t".

In the end region of the closing movement of the rotary slide f is an end switch Z which is operated by the rotary slide 1" and is operatively connected to the electromagnetic valve x in such a manner that the pulse imparted by the switch 2 on closing of the rotary slide opens the electromagnetic valve x After the described electrically controlled installation has been set manually in operation, it continues to function automatically. For starting, the circuit of the electromagnetic valve x is first closed by means of the hand switch, so that said valve allows compressed air to enter the control cylinder y The control member in the cylinder swings the flap c in the clockwise direction until the latter operates the switch z after the outlet of the collecting shaft b has been opened. The driving motor d is thereby switched on and the conveyor belt a is thus started and loose material, i.e. fine coal, is charged through the collecting shaft into the weighing container. When the weight of the loose material in the weighing container has reached a predetermined value, the rotary moving pointer g of the indicator g covers the preset pointer g", set to this predetermined value, thereby providing the disconnecting pulse for the electromagnetic valve 2: The latter shuts otf the supply of compressed air and at the same time discharges the control cylinder y so that the flap c closes the outlet of the collecting shaft and actuates the end switch Z2, imparting the stopping pulse for the motor d and thereby preventing further supply of loose material.

The electromagnetic'valve x is now opened by the second hand switch, likewise previously mentioned and not shown, whereupon the control cylinder y opens the shutter e of the weighing container e. The weighing container e discharges into the mixer f, the moving pointer g returning, and on covering the zero pointer g" giving the disconnection pulse for the electromagnetic valve x The latter interrupts the supply of compressed air to y and at the same time discharges the cylinder y so that its control member returns to the starting position and closes the weighing container e. The weighing container shutter e, at the end of its closing movement, operates the end switch Z which imparts an opening pulse for the electromagnetic valve x and hence initiates the automatic repetition of the weighing process.

By means of the third hand switch, not shown, the electromagnetic clutch k is now engaged, starting the pump 11 by the motor i. The binder is drawn by the pump I1 from the container l via the pipeline m and flowmeter n and fed to the spray nozzles p" ii1 the mixer 1; via the pressure pipeline p;

The samehand switch also imparts an opening pulse for the electromagnetic valve r, so that dueto the pressure regulatingideviceg.whicliris. connecte'dzinifront of said valve and by. means of which the amount of steam:sup plied per unit time can be regulated,.steam passes through thezpipelinesand the nozzle s to themixer. Binder: and steam thus enter the mixer at the same time. As the binder passes through the fiowmeter. n, the moving pointer of the quantity presetting instrument 0 moves until after. a predetermined quantity of'binder has passed, it

covers the preset pointer 0', thereby imparting a pulse 1 for the disengagement of the clutch k, for closing the steam electromagnetic valve r and for opening the electromagnetic valve x In accordance with this last pulse,

the control cylinder y under the action of the compressed air entering through the electromagnetic valve x opens the rotary slide f, whereupon the prcssable briquetting material, mixed with binder with the addition of steam, falls from the mixer f into the intermediate container u, which efiects equalization between the periodical arrival of briquetting material from the mixer and its continuous removal by the worm conveyor y.

When the moving pointer 0 of the binder quantity presetting instrument 0 covers the preset pointer 0" a further pulse is given for starting the adjustable time switch t.

This time switch t acts as a time-delay relay and serves to determine the charge time sequence. After the expiration of the adjusted time, the moving pointer t of the time switch I covers the preset pointer t, giving a pulse for the closing of the electromagnetic valve x The latter shuts off the supply of compressed air to the control cylinder 3' and discharges the latter, so that the rotary slide f closes and at the same time operates the end switch Z3. This end switch-after the aforesaid, re-initiated weighing process has been concluded--opens the electromagnetic valve x whereupon the weighed loose material is supplied to the mixer f. At the end of this operation, the closing shutter e operates the end switch z whereupon the supply of binder and steam to the mixer is re-initiated. A blocking member, not shown, blocks the pulse of the end switch Z before the weighing of the weighing container is concluded.

It will be seen from the mode of operation described in the foregoing, that the installation continues to function automatically after the weighing operation and the binder and steam supply have been switched on in succession by means of the aforesaid hand switches. The motor i of the binder pump and the drive of the mixer are here regarded as running continuously.

The quantity pre-adjustments by means of the indicators g and 0 ensure a high degree of accuracy of the corresponding deliveries. The pressure-regulating installation q, connected in front of the steam electromagnetic valve r--the opening time of which is determined by the binder delivery time-ensures high accuracy of the necessary steam quantity supply per charge with regard to the rate of flow per unit time in connection with the dependent duration of steam injection. The desired relationships of the function of the driving motor d of the conveyor a and the closure flap c can be readily satisfied by means of the automatic control. Due to the aforesaid time switch 1, the charge sequence can be regulated as desired and hence the mixing installation output can be matched exactly to the particular briquette press output.

A possible requirement for a proportioned delivery of different particle sizes can be met without difiiculties by the incorporation of a circular pointer balance with a plurality of circuit components, by the provision of a corresponding number of conveyors opening into the weighing container and by appropriate extension of the associated switching processes.

The degreeof perfection of the mixing effect depends toa considerable t degree; upon; the fineness; of 'thej-bind e'n dispersion, 'tlie=viscosity of? the sprayed binder and tlie i luality ofthemixer; a a With regard to-theduration of hidden injection, it is preferable to adjust the: capacity of the spraying members so that spraying time isequal to mixing time, since ex perience' has shown that only'in'this wayis it possibleto obtain= optimunr mixing' efiect;

The direction of the steam sprayingmembers will pref ei'ably be such that the inflowing' steam assists the. lbosening work of the mixer; Since uniform moi'sturedispersion in the briquetting material is of equal importance-'as th'e uniform dispersion of hinder, the principle steam injection time=mixing time also applies to the supply of steam.

Comparison of such a charge mixing installation with the aforesaid known installation operating on the ground pitch kneading process is clearly in favour of the charge mixing installation according to the invention, since with the latter practically all of the disadvantageous factors can be eliminated. In particular, the disadvantages a-d referred to in the critical analysis of the ground pitch kneading process are obviated, since the proportiom'ng of coal, binder and steam and the dispersion of binder and steam within the mixed material can be effected in an optimum manner, with simple control of the individual operations. The labour and machinery requirements mentioned under points e and f are likewise practically eliminated. It is no longer necessary for the binder to be broken up by socalled pitch breakers and crushed in an edge runner mill, but it can be supplied to the individual removal tanks by simple pumps direct from tank wagons via ordinary pipe lines. Health hazards are entirely absent, since the system is closed in itself and the formation of free pitch dust is no longer possible.

A further economic advantage of this mixing installation, is the possibility of separate regulation of the binder proportions to be added for each individual installation, so that a factory having a plurality of presses can produce different qualities of briquettes simultaneously (point g). This possibility is not available to factories with pitch supply common to all the kneading machines.

In the constructional example described, an electropneuma-tic system has been chosen for the control of the automatic operation of the installation. tem may, however, be likewise employed.

I claim:

1. Apparatus for combining the elements of a briquetting material comprising a mixing vat, an input hopper having a discharge orifice opening into said vat, a displaceable shutter covering said orifice, weighing means coupled to said input hopper for weighing the content thereof, a conveyor for conveying selected of said elements toward said hopper, a collector operatively disposed with respect to said conveyor for receiving the selected elements therefrom and having a discharge aperture opening into said hopper, a flap closing said discharge aperture, first con trol means for opening said shutter and thereby said discharge orifice, second control means for opening said flap and thereby said discharge aperture, said weighing means including a first device settable to respond to a determinable Weight in said hopper to actuate said second control means to close said flap and a second device responsive to zero weight in said hopper to actuate said first control means to close said shutter, a control responsive to the position of said flap to control movement of said conveyor, a switch correlating the position of said flap to the position of said shutter so that when said shutter is open the flap is closed, supply means for supplying a binder controllably into said vat, feed means for feeding steam controllably into said vat, and discharge means operatively associated with said vat for the discharge of briquetting material therefrom, said discharge means being coupled to said first control means to control the opening of said shutter.

2. Apparatus as claimed in claim 1 wherein the supply means for said binder comprises a binder source, a

Any other syspump coupling said source to said vat, and a flowmeter responsive to a predetermined flow of binder to control said pump, said apparatus comprising means operatively coupling said shutter to said pump to control operation of the latter in accordance With the position of said shutter.

3. Apparatus as claimed in claim 1 wherein said shutter is operatively coupled to the feed means for said steam to control the supply of steam in accordance with the position of said shutter.

4. Apparatus as claimed in claim 1 comprising a timer operatively coupled to and controlling said discharge means.

5. Apparatus as claimed in claim 1 comprising manual controls coupled to and operating said control means.

References Cited in the file of this patent UNITED STATES PATENTS 1,967,073 Zwoyer July 17, 1934 2,547,403 Madsen Apr. 3, 1951 2,727,733 Carswell Dec. 20, 1955 2,858,594 Eirich et a1. Nov. 4, 1958 FOREIGN PATENTS 230,790 Great Britain Aug. 6, 1925

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