MEANS FOR MIXING A POWDER WITH A LIQUID TO FORM A SLURRY

Abstract: A jet mixer comprising a cistern (1) to which material is supplied through two channels (3, 4) and in which the material supplied is mixed to a slurry. A pressure is generated with the aid of a pump (6) in a part of the mixture which is returned to the cistern through a nozzle, thereby causing rotation of the mixture.

Description: MEANS FOR MIXING A POWDER WITH A LIQUID TO FORM A SLURRY A great need exists for producing slurry with as high a dry solids content as possible. Various apparatuses are available which endeavour to increase the dry solids content as much as possible but so far a dry solids content of around 50% has been the most achieved. This is too low a content and also has the drawback that the slurry particles fall more quickly to the bottom of the container holding the slurry. The object of the present invention is to produce a slurry with a dry solids content of up to 85% and, according to the invention, this is achieved by supplying both powder and liquid to a container to be mixed therein. The container has an outlet at its bottom and said outlet is connected to a pump that, in one way or another, transports liquid from the outlet to the container in such a way that liquid under pressure from the outlet is sprayed into the slurry inside the container in such a way that the jet introduced into the container effects rotation of the slurry already in the container. It is recommended that the jet is directed approximately so that it is substantially at a tangent to the actual liquid quantity. The jet may thus be perpendicular to a radius of the liquid quantity. The jet may be directed obliquely upwards, obliquely downwards or exactly tangentially and several jets may be arranged around the periphery of the container. The jets may also be arranged along the height of the container. Slurry produced in this manner has great permanence thanks to its high dry solids content which results in the individual particles in the slurry taking a long time to reach the bottom of the container. The powder to be mixed with liquid may be of various types. Lime has proved to be a suitable product and lime in slurry form is extremely suitable for liming ground areas. The advantage here is that the lime tor reducing; aridity in ground areas is not blown awav since it is in the form of a sturrv. Supplying slurry, in accordance with the present invention, from the outlet to the slurrv in the container substantially perpendicularly to the radius of the liquid quantity, produces marked homogenisation of existing slurry in the liquid. The present invention will be described further with reference to the accompanying drawings in which Figure 1 shows a mixer according to the invention seen from the side and Figure 2 shows the mixer in Figure 1 seen from above. The drawings show a cistern 1 with a lid 2 and two channels 3 and 4 for the supply of liquid and powder. The lower end of the cistern 1 is provided with an outlet which is connected to an outlet pipe 5, in turn connected to a pump 6 which may be a centrifugal pump, for instance. The outlet end of the pump is provided with a connection 7 to the cistern, the connection 7 having an orifice opening into the cistern, below the surface of the slurry in the cistern. The inner surface of the connection 7 is provided with a nozzle directed so that slurry in the cistern is set in rotation about the axis of the cistern. It is therefore suitable for the nozzle to be directed substantially perpendicularly to the radius of the cistern, in which case it may be situated between the centre and the periphery of the cistern. Several nozzles may also be arranged in parallel beside each other. Said nozzle may also be directed slightly upwardly, slightly downwardly or purely horizontally in relation to the cistern. The nozzles may also be arranged around the periphery of the cistern and they may also be placed between the upper and lower ends of the cistern. However, the nozzles must always be located below the surface of the slurry in the cistern. The cistern may of course be provided with a mechanical stirrer if necessary. The device according to the invention functions by liquid first being supplied to the container and then tapped at the bottom of the container and returned to the container via the pump 6, whereupon the liquid is immediately set in rotation about the axis of the cistern. When sufficient liquid has been supplied, powder is added. Thanks to said rotation, the present invention allows a slurry to be produced having a dry solids content of up to 85%. Slurry with this dry solids content can be withdrawn by suitable means from the cistern 1 for any purpose desired. It has been found that, when the powder used is lime, the slurry obtained is particularly suitable for liming ground areas. Liming was previously carried out using only dry substance but supplying it in the form of a slurry gives the advantage that the wind cannot influence it to the same extent as a dry substance.

Claims: CLAIM 1. Equipment for mixing a powder with a liquid to form a slurry in a container with an outlet allowing the slurry to be tapped, characterized in that a pump (6) is connected to the outlet, said pump (6) supplying slurry under pressure, the slurry being returned to the container (1) in the form of a jet in such a manner that it encounters the slurry in the container (1) thereby causing rotation of the mixture.

Inventors: ALLERT STEFAN, ALLERT, STEFAN
Applicants: ALLERT STEFAN, ALLERT, STEFAN
Application year: 1995
Main classification: B01F3
IPC codes: B01F5, B28C5