Dispensing – Processes of dispensing
Patent
1992-07-02
1994-02-15
Kashnikow, Andres
Dispensing
Processes of dispensing
222 56, 222161, 177 59, 177121, 177122, 177DIG11, B67D 508
Patent
active
052859304
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention concerns a method of dosing fibres, such as steel fibres to be mixed in concrete, and where a supply of fibres is stored in a first vibration feeder and is fed from this by means of a second vibration feeder.
BACKGROUND OF THE INVENTION
Fibres of various types are used today to an increasing degree for i.a. reinforcement of cast materials. Thus, reinforced concrete can be produced by adding steel fibres directly during the actual mixing process, which must then be distributed very carefully and uniformly if the finished concrete is to have the required homogenous and isotropic properties. However, this has not been possible to a satisfactory degree by means of the conventional dosing methods which tend to feed the steel fibres in the form of more or less tangled lumps.
The Danish published publication 153 450 B discloses a method and an apparatus for improving steel fibres which are present in bundles or packed lumps, and which, directionally oriented, are to be dosed to an airborne stream of material, such as a sprayed concrete mass. This takes place by tearing the bundles or the lumps apart in preferably a rotating drum with inwardly facing pegs, and gradually discharging the loosened steel fibres during the rotation through variable opening in the drum on an inclined chute, where the fibres are replaced by sliding down the chute under the action of gravity, said chute being constricted in a direction toward the lower end. The fibres now unidirectional are then sucked by a strongly sucking air stream into a pipe stub and further into a transport conduit, in which the unidirectional fibres are fed in an even flow to the mouthpiece in a spray assembly and are sprayed together with the concrete mass mentioned by way of example onto a surface. Tangled fibres can hereby effectively be loosened from each other and be conveyed in an evenly dosed stream with unidirectionally oriented fibres to and be used in e.g. a spray assembly for successive application of fibre-filled concrete on a surface. However, this known method is unsuitable when the fibres are to be used as reinforcement in cast concrete. The reason is that in this case the fibres are to be fed to the concrete mixer evenly and uniformly within a relatively short period of time in a predetermined portion in a loosened, but precisely not unidirectional state.
SUMMARY OF THE INVENTION
The object of the invention is therefore to provide a method of the type stated in the opening paragraph by which it is possible to add a predetermined quantity of fibres to a process more accurately and uniformly than known before.
This is achieved in that the method of the invention is characterized in that a quantity of fibres proportioned for a dosing operation is transferred at a stepless rate or a stepwise declining rate from the first to the second vibration feeder while said feeder stands still, and that the second vibration feeder transports the transferred fibre quantity further on while the first vibration feeder stands still. The tangled fibres are hereby loosened from each other during the vibrations already in the first vibration feeder, which can therefore add to the second vibration feeder an evenly distributed layer of loose fibres which can then rapidly and uniformly be introduced into the mixing process at the desired time.
With a view to accurately proportioning the quantity of fibres to be used in each individual case, the fibres can be transferred according to the invention at an initially relatively great rate and in the end phase at a considerably lower rate.
When the vibrations are generated by electromagnetic vibrators and the second vibration feeder is positioned on electronic weighing cells, dosing may be automatized in an advantageous embodiment of the method of the invention in that the instantaneous amplitude of the vibrations of the first vibration feeder is determined by signals which the weighing cells currently apply to a preprogrammed control unit to which the respective vibrator is connected, a
REFERENCES:
patent: 448853 (1891-03-01), Corey
patent: 2311373 (1943-02-01), Durning
patent: 2333338 (1943-11-01), Rapp
patent: 2701703 (1955-02-01), Evers
patent: 2738944 (1956-03-01), Lindstaedt et al.
patent: 2863651 (1958-12-01), McBride
patent: 3001672 (1961-09-01), Wahl
patent: 3117639 (1964-01-01), Dreeben
patent: 3578094 (1971-05-01), Henry
patent: 3638922 (1972-02-01), Guglietti
patent: 3696584 (1972-10-01), Rickard
patent: 3944004 (1974-07-01), Lafitte et al.
patent: 3957126 (1976-05-01), Hobart
Bomberg Kenneth
Kashnikow Andres
Skako A/S
LandOfFree
Method of dosing fibres does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of dosing fibres, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of dosing fibres will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1201371