US 4,275,836 A · Method and apparatus for spraying concrete

Abstract

To reduce the impact velocity of the concrete mass upon a surface, such as a wall, a branch line is arranged at the concrete conveying hose and at a point removed from the spraying nozzle. The branch line is intended to carry compressed air and opens into the surroundings. This branch line has a valve for regulating the quantity of compressed air which is to be withdrawn. By means of the branch or withdrawal line there is appreciably reduced the rebound of the concrete mass at the wall. The concrete mixture is initially pre-moistened to a constant moisture content before it arrives along the spraying or injection path and at the spraying or injection nozzle there is added thereto a constant residual water quantity. This method affords a continuously constant water content and renders possible reduced pressure of the conveying air since the concrete mixture is only pre-moistened at the conveying path.

Claims9

Dependent claims

A method of spraying concrete by means of compressed air, comprising the steps of:

pre-moistening a mixture composed of cement and additives with an at least approximately constant moisture content;
feeding the mixture in a continuous stream by means of compressed air along a conveying path to a spray nozzle for spraying thereof;
adding to the pre-moistened mixture, directly at the region of the spray nozzle, an essentially constant quantity of water;
and
exhausting at least part of the compressed air serving as the conveying medium, continuously and concurrently with the continuous spraying of the mixture, out of the conveying path forwardly of part of the conveying path serving as a braking path for the continuously fed mixture stream along the path to the spray nozzle.

2 more elements

Dependencies are inferred from the claim text.

Method and apparatus for spraying concrete

Life of this patent

Method and apparatus for spraying concrete

Life of this patent

Abstract

Claims9