DE1144018B - Method and device for automatic weighing of free-flowing bulk goods - Google Patents

Description

GERMAN

PATENT OFFICE

H32028IXc / £ 42

REGISTRATION DATE: DECEMBER 31, 1957

NOTICE THE REGISTRATION AND ISSUE OF EDITORIAL: FEBRUARY 21, 1963

The invention relates to a method for automatic weighing of flowable bulk material and to a Scales for carrying out the procedure.

In the previously known weighing method, either a predetermined weight is set just below the target weight The lying amount is pre-dosed into the weighing pan and then adjusted to the target weight by supplying a fine bulk material flow controlled by the balance beam is filled, or the weighing pan is filled initially pre-filled by a strong flow of bulk material and this then in the last phase of the filling throttled until it is switched off at the target weight. The control takes place depending on the position of the balance beam either mechanically, electromechanically or pneumatically. With these weighing methods However, it cannot be avoided that after switching off the bulk material supply a certain Quantity of bulk material that is between the discharge of the conveyor at the moment of switch-off and the weighing pan is also falling into the weighing pan.

In order to take this additional amount into account in the weighing process, the Bulk material supply by means of a so-called wake regulator even before the equilibrium position is reached turn off, the setting being made so that the initially resulting incorrect weight practically through the amount of bulk material flowing in is compensated.

Experience has shown, however, that even such methods are not always sufficiently accurate Ensure filling weights, as the afterflow regulator is set to a certain value on the one hand must, but on the other hand the weight of the bulk material flowing in, for example as a result of fluctuations in the specific weight of the product or as a result of irregularities in the Bulk material supply can change continuously. This is especially true for revolving scales where the strength of the product flow is not insignificant due to the increasing speed with the circulation Centrifugal forces is influenced.

The invention aims to eliminate the previous disadvantages and to develop a weighing method, that works without a refill and thus the causes for the sources of error mentioned from the outset avoids.

To this end, the invention relates to a method for the automatic weighing of flowable Bulk material, which is first fed to a weighing pan in an amount exceeding the target weight will.

Method and device

for automatic weighing

of flowable bulk material

Applicant:

Ms. Hesser,

Maschinenfabrik-Aktiengesellschaft,
Stuttgart-Bad Cannstatt

Adolf Stambera, Stuttgart-Bad Cannstatt,
has been named as the inventor

A method of this type is also already known. Here, however, the excess weight becomes off suctioned off the weighing pan again, so that the weighing pan is more or less influenced by this suctioning off will. In addition, the aspirated material is piled up in a more or less uneven cone Experience has shown that the contents are never even. But the latter is an absolute requirement for an exact weighing. Furthermore, the known method requires due to the suction system a considerable amount of machinery. In other known methods of this type, corresponding the size of the overweight put a corresponding number of suckers in action, which each suck off a piece of sugar from the amount on the scales. So they are here too cumbersome suction devices required. After all, it is especially for chemical-analytical Purposes known, automatically small amounts of preferably non-powdery, solid substances weigh in the goods to be weighed with electronically controlled vibration feed. This is the one Use of a weighing scale, which enables an exchange of such particles, which once hit the load pan such scales have fallen against others that are better in weight. With this one Process should not, in principle, initially create an overweight on the scales, but rather - as mentioned - an exchange of particles of the bulk material should be carried out, if the bulk material that was last transported onto the weighing pan is too heavy.

In contrast, the present method for automatic weighing is characterized in that it

309 510/122

according to the invention the amount of bulk material determined as excess when weighing, in per se known Way controlled by the balance beam, in free flow solely by the effect of gravity flows out of the weighing pan. The essential advance of this method according to the invention exists in the fact that any external influence on the weighing pan is avoided and this is the prerequisite for a high weighing accuracy.

To carry out the method according to the invention, in a further development of the invention, the balance be designed so that the weighing pan has a drain opening that can be closed by means of a slide and the slide mechanically or electromechanically when the balance beam is in equilibrium is closed, and that this scale with a screw, a conveyor belt, an elevator Od. The like. Containing return conveyor is connected, which flows out of the drain opening The bulk material is conveyed back to the feed device of the scales.

The invention is based on an exemplary embodiment Explained in the drawings. It shows

1 shows a weighing unit of a rotating multiple scale,

FIG. 2 shows the weighing pan according to FIG. 1 on a larger scale,

FIG. 3 is a front view of the weighing pan according to FIG. 2.

The weighing unit shown in Fig. 1 consists essentially of an inlet pipe 1, which is connected to a distributor pipe 2 and can be closed over the weighing pan 9 by two electromagnetically operated gate valves 3, a scale 4 of a known type, which is attached to a carrier 5 is suspended, and from a drain pipe 6 which is in connection with a return conveyor 8 formed for example by a screw conveyor 7 or the like.

In the present example, a running weight scale is used, which consists of the weighing pan 9, the Balance beam 10 and a running weight 11 consists. The weighing pan 9 has two bottom flaps 12, which in can be opened in a manner known per se via a linkage 13 by means of an electromagnet 14. The weighing pan 9 also has a bulge 15, on the underside of which there is a drain opening 16 is attached, which can be closed by means of a gate valve 17. The operation of the gate valve 17 takes place by means of an electromagnet 18 attached to the weighing pan 9, which is dependent on is controlled by the position of the balance beam 10.

Below the drain opening 16 is the inlet of the drain pipe 6, which is the one from the drain opening 16 Exiting excess bulk material brings it to the return conveyor 8, which then carries it on promotes into the manifold 2. The return conveyor 8 is in the present example in a rotatable Column 19 built in, the central support for a larger number of the described circumferential Forms weighing units.

The operation of a weighing unit is as follows. First, the weighing pan 9 is via the inlet pipe 1 filled with a quantity of bulk goods that is greater than the weight of the bulk material. For example, this can be either by volumetric or time-dependent dosing using electrical or mechanical Dosing devices take place. This dosage can also be done by controlling the gate valve 3 take place from the balance beam 10, which is provided for this purpose with control contacts that are in the circuit of the gate valve 3 actuating electromagnet 20.

Simultaneously with the completion of the filling of the weighing pan, the gate valve 17 becomes the drain opening 16 opened so that the product can flow out of this in a fine stream. As soon as the scales Has reached equilibrium, the control contacts, not shown and influenced by the balance beam, open of the electromagnet 18, whereby the drain opening 16 is closed again. The emptying the weighed amount from the weighing pan is now done in the usual way.

The operation of the gate valve 17 at the drain opening 16 does not necessarily have to be done by one of the Weighing pan itself attached electromagnets, but can just as well from the outside through a mechanical one permanently attached to the weighing device or electromechanical device happening at the moment of equilibrium of the The balance becomes effective and the drain opening closes.

Claims (4)

PATENT CLAIMS: 1. A method for automatic weighing of flowable bulk material, which is first fed to a scale pan in an amount exceeding the target weight, characterized in that the amount of bulk material determined as excess when weighing, controlled in a known manner by the balance beam, in the open Flow out of the weighing pan solely through the action of gravity. 2. Scales for performing the method according to claim 1, characterized in that the weighing pan (9) by means of a mechanically or electromagnetically operated slide (17) on reaching the equilibrium position of the balance beam (10) closable drain opening (16). 3. A balance according to claim 2, characterized by one, for example a screw (7) Conveyor belt or an elevator containing return conveyor (8) through which the the discharge opening (16) flowing out of the bulk material of the feed device feeding the weighing pan (2, 1) can be fed back. 4. Scales according to claims 2 and 3, characterized in that several weighing units (4) around a common feed and distribution device (2) and the entire return device (8) for all weighing units having stand (19) circumferentially arranged are. Documents considered: German Patent No. 948 644; French Patent Nos. 843 613, 878 293, 777;
U.S. Patent No. 1646,817. 1 sheet of drawings © 309 510/122 2.