The storage and processing times of sprayed concrete can be significantly extended by the addition of a retarder which is a chemical compound which is capable of chelating with calcium ions. Preferred retarders are phosphonic acid derivatives which have at least one amino and/or hydroxyl group. The retarder can be used for both wet- and dry-sprayed concrete, the usual accelerators can be used for ...

The storage and processing times of sprayed concrete can be significantly extended by the addition of a retarder which is a chemical compound which is capable of chelating with calcium ions. Preferred retarders are phosphonic acid derivatives which have at least one amino and/or hydroxyl group. The retarder can be used for both wet- and dry-sprayed concrete, the usual accelerators can be used for ...

The storage and processing times of sprayed concrete can be signifi- cantly extended by the addition of a retarder, a chemical compound which is capable of chelating with calcium ions. Preferred retarders are phos- phonic acid derivatives which have at least one amino and/or hydroxyl group. The retarder can be used for both wet- and dry-sprayed concrete, the usual accelerators can be used for acti...

The present invention provides a method and apparatus for manufacturing span bond nonwoven fabrics formed from continuous fibers which are small in fineness and high in strength. That is, according to the present invention, non-oven fabrics are manufactured by the steps of spinning for obtaining a continuously drawn fiber by blowing a molten resin extruded out of a spinning nozzle by heated gases ...

The filler (3) mounted on a bearing (2) in line with the axis of a support (1) is propped up by a framework (3) on which a rotary bearing (6) carries the transfer station (7) on the cylinder cover (20). A pneumatic feed tube (8) ends in a drum (9) from which the filling slides (10) into a chute (11) while air is released through a filter (12). Electric power is supplied via a commutator (17) and s...

The storage and processing times of sprayed concrete can be significantly extended by the addition of a retarder which is a chemical compound which is capable of chelating with calcium ions. Preferred retarders are phosphonic acid derivatives which have at least one amino and/or hydroxyl group. The retarder can be used for both wet- and dry-sprayed concrete, the usual accelerators can be used for ...

A method and an apparatus for the denitrification and desulfurization of hot waste gases, particularly from furnaces. A crude gas flow is initially conducted through a denitrification plant and through the endothermic part of a heat-utilizing plant. Subsequently, the flow is conducted into a desulfurization plant. The purified gas flow discharged from the desulfurization plant is conducted through...

The cloth advance mechanism on a sewing machine utilises a double sided coupling, each section having a step mechanism connected through control plates to the drive shaft of the cloth advance wheel. - The mechanism is situated beneath the sewing table, with the advance wheel protruding to contact the base of a revolving pressure foot, alongside the needle, and against the stitch formation gripper....