Method and apparatus for spraying an inorganic hydraulic material composition containing reinforcing short fibers

An apparatus for spraying a wet composition containing an inorganic hydraulic material and a reinforcing material by means of a blast of compressed air, said apparatus comprising:

• a single source of a supply of a blast of compressed air;
• a fluidizing device having a fluidizing space formed therein, said fluidizing device connected to the source of supply of the blast of compressed air and connected to a source of supply of reinforcing short fibers, wherein a flow of reinforcing short fibers fluidized in the blast of compressed air is provided;
• a dry blender having a dry blending space formed therein and connected to the fluidizing device, said dry blender located below and connected to a source of supply of a dry mixture of an inorganic hydraulic material with an aggregate, wherein the dry mixture is allowed to fall down into the dry blending space and a flow of dry blend, containing the inorganic hydraulic material the aggregate and the reinforcing short fibers fluidized in the compressed air blast, is provided;
• a water-mixing device having a water-mixing space formed therein, said water-mixing device connected to the dry blender and connected to a water-spouting device for spouting water into the water-mixing space, connected to a source of supply of water, wherein a flow of a wet composition consisting of the dry blend and water evenly mixed and fluidized together in the compressed air blast is provided;
• and
• a spray nozzle connected to the water-mixing device.