The present invention relates to a method for mixing granular and/or pulverulent materials with each other and/or a liquid.

When mixing e.g. concrete in small batches, as in small repair jobs or the like, the components are usually placed on a board or in a receptacle and manually mixed with each other by means of a shovel or other tool. This is a heavy and time-consuming toil. The necessary cleaning of the board or the receptacle after completed use also is a laborious task. Although there are mechanical mixers with mixing means rotating relative to a mixing receptacle, these mixers do not always provide a satisfactory mixing effect and also are relatively expensive.

A first object of the invention therefore is to provide a method of the type stated by way of introduction, which ensures efficient mixing with small efforts and at a low cost.

When mixing pulverulent materials, there usually is a substantial formation of dust which may be environmentally unacceptable. The problems of dust formation may be encountered in both manual and mechanical mixing. Another object of the invention is to entirely eliminate the emission of dust to the environment.

These two objects of the invention are achieved by a method of the type stated in the introduction to this specification, which has the features disclosed by appended claim 1.

To make it easier to perform the lifting movements, each end of the tube preferably is provided with a handle. These handles may consist of holes through the tube at the ends thereof.

In order to introduce the batch in the tube, this is suitably open or openable at least at one end thereof. If the other end of the tube is closed, the tube may also serve as a package for the granular and/or pulverulent materials.

To ensure a dust-free supply of the granular and/or pulverulent materials from a standard package, e.g. a bag, the circumference of the tube is made larger than the circumference of the package. In this manner, the open end of the tube can be passed over the package which can thus be emptied of its entire contents or part thereof in a dust-free manner.

Preferrably, the tube is made of a transparent material, such that the progress of the mixing operation can be directly observed.

It is evident that the invention ensures efficient mixing with only small manual efforts. Further, the dusting and cleaning problems are reduced to an acceptable level.

The tube also offers the advantage of allowing convenient transport of the mixed material to the place of use. Cleaning of the tube normally consists only in washing the inside of the tube. If some of the mixed material is left in the tube so as to dry and get stuck to the inner side thereof, it can easily be removed by lightly shaking the tube thanks to the pliability thereof.

It should be emphasised that the invention is not restricted to the mixing of concrete but is also well suited for mixing any granular and/or pulverulent materials with or without the addition of liquid.

The invention will now be described in more detail hereinbelow with reference to the accompanying drawings. Fig. 1 is a top plan view of an embodiment of the device used according to the invention. Fig. 2 shows an alternative embodiment of the device according to Fig. 1. Fig. 3 is a side view of the device according to Fig. 1 containing a batch ready for mixing. Fig. 4 is an example showing how the device can be filled with materials to be mixed. Fig. 5 shows the device in Fig. 3 with a cross for further reducing the mixing efforts.

The device used according to the invention and shown in Figs. 1-3 consists of a tube 1 of a pliable web having ends 2 and 3 reinforced by doubling over the web. Holes 4, 5 are formed in the doubled portions at the ends 2 and 3 and have such a shape that the user's hands can be passed therethrough to obtain a steady grip at each end of the tube.

The doubled end portions of the tube 1 and the holes 4 and 5 thus provide a handle at each end of the tube 1. The ends 2 and 3 can be further reinforced e.g. by means of a strip 6 shown in Fig. 2, which has a hole corresponding to the hole 4.

The use of the device according to the invention is illustrated in Fig. 3, where a batch 7 of granular and/or pulverulent materials and a liquid, e.g. a batch of sand, cement and water, has been placed in the central part of the tube 1. This central part of the tube 1 rests on a stationary supporting surface 8, and the ends 2 and 3 of the tube are held in an upwardly stretched state by the hands of a user (not shown). By alternately lifting and lowering the ends 2 and 3 while maintaining a portion of the central part of the tube in contact with the surface 8, it is possible to achieve a highly efficient mixing of the components in the batch 7. More specifically, the lifting movements are performed to such an extent that the materials in the batch 7 are thoroughly blended. Such blending can be achieved in that the outer portions of the batch 7 as shown in Fig. 3 are alternately lifted and shifted sideways in over the central portion of the batch 7. Thus, the central portion of the batch 7 will successively be superposed by new layers consisting of the material raised from the outer portions of the batch 7. Concurrently with such successive superposition of new layers on the central portion of the batch 7, there is also a motion of material out from the central portion of the batch 7 towards the outer portions thereof, which motion of material occurs alternately as a result of the alternate lifting of the ends 2 and 3 of the tube.

Practical tests have shown that the device now described provides highly efficient mixing in a very short time and with small efforts.

In order to fill the tube 1 with the materials to be mixed, the tube suitably is open at least at one end thereof. Further, the tube 1 has such a circumference that it can be passed over a package 9 with the material to be mixed, as shown in Fig. 4. Before the tube 1 is passed over the bag-like package 9, its upper end has been cut open so that after passing the tube over the package, the entire contents or part of the contents thereof can be emptied into the tube 1 by lifting the lower end of the package 9. In this way, there will be practically no dust formation from the material in the package 9.

The manual efforts required for mixing the batch can be further reduced by using a rocker consisting of a cross 10 as shown in Fig. 5. The cross 10 more specifically has arms on the ends of which the handles of the tube 1 are supported. The vertical part of the cross serves as a supporting leg the lower end of which engages the stationary supporting surface. By rocking the cross back and forth, as indicated by the double arrow, alternate lifting of the ends 2 and 3 of the tube 1 is achieved.

It goes without saying that the lifting movements described above may just as well be executed by mechacal means. They can also be performed with one end of the tube fixed, e.g. hung from a hook, while the other end of the tube is alternately lifted and lowered to a level respectively above and below the fixed end of the tube which, in this case, should however not rest on a supporting surface.

Modifications of the tubular device described above are of course possible within the scope of the invention. Thus, the tube need not be open or openable at any of its ends but may have a suitable opening provided between the ends. The tube may also serve as a package for the granular and/or pulverulent materials.