Mortar spray gun, device comprising same, and spraying method

A method for spraying a wet mortar configured to harden to form a construction element, the method comprising the following stages:

• e.1. preparation of a wet mortar by mixing water with at least one binder comprising particles, the D50 of which is less than or equal to 150 μm, with aggregates, at least a part of these aggregates having:
• a particle size D50 of between 1 and 15 mm, and
• a form factor F defined as being the ratio of the largest dimension of an aggregate to its smallest dimension, such that F is different from 1;
• e.2. spraying of this wet mortar using a spraying device for a wet mortar comprising:
• at least one pump for circulating the wet mortar, the pump for circulating the wet mortar being selected from eccentric screw pumps comprising a pumping jacket with a number of screw pitches of equal to either 3 or 4,
• at least one source of spray fluid,
• and at least one spray gun comprising:
• a gun body comprising:
• at least one inlet for a flow of wet mortar configured to be connected to a supply line for this flow of wet mortar,
• at least one opening for injection of a jet of spray fluid,
• and at least one chamber for bringing the jet of spray fluid into contact with the flow of wet mortar,
• at least one duct for guiding the flow of wet mortar from the inlet of the gun body up to the contacting chamber, and
• at least one outlet for sprayed wet mortar,
• at least one injector mounted on the injection opening and comprising at least one head emerging in the contacting chamber, this injector being capable of producing a jet of spray fluid in the direction of the outlet of the gun body, the injector being configured to be connected to a pipe for feeding with spray fluid,
• at least one spray nozzle for the mortar, configured to be mounted on the outlet of the gun body, and
• at least one connection end piece mounted on the inlet of the gun body provided for the admission of the flow of wet mortar,
• wherein
• a. the pressure of the jet of wet mortar at the nozzle outlet is between 5 and 30 bars,
• b. the guiding duct is designed so that the flow of wet mortar within this duct is monodirectional or multidirectional, with the condition according to which any change in the direction of the flow corresponds to an angular deviation ED of less than or equal to 30°,
• c. the position of the injection head of the injector in the contacting chamber is adjustable, and
• d. the wet mortar is constituted by a pasty matrix including aggregates,
• (d.1) the matrix being constituted by a mixture comprising at least one liquid, at least one binder comprising particles with a particle size D50 of less than or equal to 150 μm,
• (d.2) at least a part of these aggregates having:
• a particle size D50 of between 1 and 15 mm, and
• (d.3) and a form factor F defined as being the ratio of the largest dimension of an aggregate to its smallest dimension, such that F is different from 1.