DE1598373B1 - Process for the continuous monitoring of the density of foam concrete raw mass in compulsory mixers - Google Patents

Description

The invention relates to a method for continuous monitoring the density of foam concrete raw mass in compulsory mixers during the addition of the solids, Water and foam.

It is well known that the production of high-quality components is interrupted z. B. lightweight aggregate foam concrete that a very precise dosage of the Additive and binding agents are adhered to and the specified mixing times are precisely adhered to. Above all, however, is the density of the raw foam concrete mass to be adhered to with the greatest possible accuracy.

This requirement is crucial because exceeding the target density results in higher material consumption, which in turn means a considerable reduction in the thermal insulation properties to be striven for the concrete elements is connected.

Falling below the target density, however, causes an unjustifiable Reduction in strength, which above all also increases the breakage rate, which is undesirable when transporting the finished parts.

It is known to use foam concrete to maintain constant target densities either add foamed constant amounts of foam concentrate or by measuring the Filling heights in the compulsory mixer, the densities of the foam concrete raw masses in a simple manner to be determined by dipping a dipstick.

Because of the different foaming and foamability of the Foam concentrates occur scattering of the density of the foamed concrete raw mass by an average plus / minus 10 0 / o; The cause is on the one hand technically imperfect foam generators and on the other hand the unavoidable inaccuracies when reading the values from immersed dipstick.

It also proves to be a hindrance or impairment that the inherent moisture the ashes used to produce foam concrete can vary within wide limits.

The present invention has the purpose of both To prevent exceeding as well as falling below the target gross density in order to thereby To achieve constant strengths and material savings and optimum thermal insulation properties to guarantee for the prefabricated parts.

The task is therefore seen in developing a process with which it is possible to reduce the spread of the bulk density so far that a Accuracy of plus / minus 2 0 / o is maintained.

According to the invention the object is achieved in that by means of a attached in the center under the mixer base or outside on the wall of the compulsory mixer Surface neutron probe the hydrogen concentration in the introduced raw mass is continuously measured and registered and the measurement in the subsequent The addition of water and foam is continued and followed until the established one The target density of the finished mixture has been reached.

Then the foam is added to the raw sludge, which causes them to be pushed apart The festival- fabric parts - e.g. B. the ash and the cement - and the water parts will. This has a reduction in the hydrogen concentration in the raw foam concrete mass result, which in turn is a direct measure of the decrease in density of the same is.

When the target density of the foam concrete raw mass is reached, the foam addition is completed; this is done by tracking the pointer deflection of a display device, e.g. B. a pulse density meter or automatically by using z. B. Threshold transducers enables.

By using the method according to the invention, both Falling below the gross density - and thus also falling below the demanded Concrete strength - and, on the other hand, also prevents the gross density from being exceeded, resulting in a material saving of at least 5% compared to the previously known Procedure leads.

The invention is explained in more detail below using an exemplary embodiment explained and described: A compulsory mixer is placed in the center under the floor or a surface neutron probe at a favorable point on the mixer wall known design attached.

When the mixer is empty, it shows a pulse density of N0; after this Filling the axle and the cement increases - depending on the respective water content the ash - the momentum density on Nt.

Now water is added until the target density of the Raw sludge is reached, the z. B. corresponds to a pulse density of N2.

The foam is then fed in immediately, until the Target density of the mass of foam concrete is reached and z. B. a pulse density of N3. After that, there is only a constant amount of lightweight aggregate mixed in, with the formation of additional air pores causing a further drop the momentum density can be observed.

After emptying the mixer, the device shows the original again Pulse density No.

Claims (2)

Claims: 1. A method for continuous monitoring of the Density of foam concrete raw mass in compulsory mixers during the addition of solids, Water and foam, d a d u r c h, that means one in the center under the mixer base or the surface neutron probe attached to the outside of the wall of the compulsory mixer the hydrogen concentration of the raw material introduced is continuously measured and is registered and the measurement during the subsequent addition of water and foam continued and tracked until the specified target bulk density of the finished mixture is reached. 2. The method according to claim 1, characterized in that the measurements indicated by means of a pulse density meter or using threshold sensors and evaluated.