Aerosol or spray device, spray nozzle unit and method of manufacturing the same
A method for manufacturing an spray device includes assembling at least one spray nozzle plate into a thermoplastic holder, while controlling the temperature of the spray nozzle plate and/or the holder and as a result at least locally plastically deforming the holder permanently. After the thermoplastic deformation of a seat of the holder, a diameter of the seat of the holder upstream of the spray nozzle plate exceeds a diameter of the seat of the holder downstream of the nozzle plate. The thermoplastic holder may have a tapered seat, where the smallest cross section of the tapered seat is smaller than the spray nozzle plate, where a widest side of the tapered seat is pointing towards a supply side of the liquid.
1. A spray device having a spray nozzle unit, said spray nozzle unit comprising holder of thermoplastic material and a spray nozzle plate, wherein said spray nozzle plate comprises at least one spray nozzle orifice, wherein said holder comprises a recess that is open on opposite ends thereof and at least a portion of said recess tapers down towards a downstream end thereof, wherein said spray nozzle plate is fitted within said tapering portion of said recess, wherein said recess has a thermoplastic wall with a seat that holds said spray nozzle plate, wherein said seat comprises a first rim that sealingly engages a downstream surface of said spray nozzle plate and extends all along a circumferential edge of said downstream surface of said spray nozzle plate, wherein said seat comprises a second rim that engages an upstream surface of said spray nozzle plate and extends all along a circumferential edge of said upstream surface of said spray nozzle plate, wherein said spray nozzle plate has a lateral cross section in between a first lateral cross section of said seat at an upstream end and a second lateral cross section of said seat at a downstream end, wherein said first rim comprises a first thermally deformed portion of said thermoplastic wall of said recess, and wherein said second rim comprises a second thermally deformed portion of said thermoplastic wall of said recess.
2. The spray device according to claim 1 , wherein the spray nozzle plate is a ceramic plate or metal plate.
3. The spray device according to claim 2 , wherein the spray nozzle plate is a plate of semiconductor material, particularly of silicon.
4. The spray device according to claim 1 , wherein said recess comprises a further seat that holds a filter plate having a plurality of filter openings, wherein said second rim sealingly engages a downstream surface of said filter plate and extends all along a circumferential edge of said downstream surface of said filter plate, wherein said further seat comprises a third rim that engages an upstream surface of said filter plate and extends all along a circumferential edge of said upstream surface of said filter plate, wherein said filter plate has a lateral cross section in between a first lateral cross section of said further seat at an upstream end and a second lateral cross section of said further seat at a downstream end, and wherein said third rim comprises a third thermally deformed portion of said thermoplastic wall of said recess.
5. The spray device according to claim 4 , wherein the filter plate is a ceramic plate or metal plate.
6. The spray device according to claim 5 , wherein the filter plate is a plate of semiconductor material, particularly of silicon.
7. The spray device according to claim 1 , wherein a width of the first rim in a direction parallel to the downstream surface of the nozzle plate is at least 25% of a thickness of the nozzle plate.
8. The spray device according to claim 1 , wherein, in a direction perpendicular to the downstream surface of the nozzle plate, the first rim has a thickness of minimum 50% and maximum 250% of a thickness of the nozzle plate.
9. The spray device according to claim 4 , wherein in a direction perpendicular to the downstream surface of the spray nozzle plate, the second rim has a thickness of at least 50% and maximum 250% of a thickness of the filter plate, in particular with a thickness of minimum 100 and maximum 500 micrometer.
10. The spray device according to claim 4 , further comprising a pre filter made of a sintered porous plastic material, mounted within said recess further upstream from the spray nozzle plate and the filter plate.
11. The spray device according to claim 1 , further comprising an adapter having an inner surface that fittingly holds an outer surface of the holder, a stiffness of the adapter exceeding a stiffness of the holder.
12. The spray device according to claim 11 , wherein the adapter comprises an adapter rim extending at a downstream side of the holder and substantially parallel to a downstream surface of the holder so as to support the holder during operation.
13. The spray device according to claim 11 , wherein said outer surface of the holder abuts said inner surface of the adapter along a tapering section that tapers positive in a downstream direction at a tapering angle between 5 degrees and 45 degrees.