Atomiser having a plunger tube

In an atomiser comprising a plunger tube, a pump chamber connected to the plunger tube by means of a check valve, a piston having a lip slidably mounted in that chamber, a tube slidably mounted in that piston and operatively connected to the latter so that, when the tube is moved axially, it drives the piston, a control button carrying a nozzle connecting with the tube and capable of moving the latter when the button is pressed, a valve carried on the end of the tube opposite the button and capable of being applied on a seat at the lip end of the piston, the tube containing in proximity to said lip end at least one hole opening inside the piston, and a spring which is inserted between the valve and the bottom of the chamber and tends to apply the valve on its seat and, to bring the piston into a rest position in which it blocks a free air opening of the container holding the liquid to be sprayed, the improvement comprising:

• the pump chamber being of the shape of a truncated cone the surface of which is plane, the lip of the piston being of decreasing crosssection as it extends from the valve seat to the free end of the piston, the free end being situated at the larger base of the pump chamber in its rest position said free end having an outside diameter no less than the inside diameter of the larger base of the pump chamber and the free end being radially compressed by the pump chamber as it is moved axially into the pump chamber.