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(11) | EP 0 374 117 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Spray apparatus |
(57) Spray apparatus fo carrier-less high pressure spraying of materials, for example
mortar, comprising a pump housing (31) having an inlet (9) for the material with an
associated non-return valve (13), and having an outlet (11) for the material with
an associated counter-placed non-return valve (23), and pressure means (41) generating
alternately pressure and suction for pressurizing and feeding the material. The spray
apparatus further comprises a mobile piston (43), which is placed under a determined
but adjustable counter-pressure, so that when a pre-selected pressure has been generated
in the pump housing (3) this pressure will be maintained at a constant level by displacing
the mobile piston (45) outwardly so as to increase the dead volume (51) of the pump
housing. |