Dispensing – With discharge assistant – With movable nozzle interconnected therewith
Patent
1996-10-28
1998-09-08
Derakshanj, Philippe
Dispensing
With discharge assistant
With movable nozzle interconnected therewith
2223219, G01F 1100
Patent
active
058033181
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to an improved precompression pump, and more particularly to a miniaturized pump generally actuated by means of a finger and intended for spraying fluids, generally liquids or semi-liquids such as perfumes, pharmaceuticals, or cosmetics.
An example of a manual precompression pump is described in FR 2,403,465. That type of pump comprises a hollow cylindrical pump body in which there slides an annular piston, said piston being controlled by a push rod which slides in the pump body via a lateral opening. The pump body and the piston together define a pump chamber, and the piston is displaceable relative to the push rod so as to close the lateral opening of the outlet channel or, on the contrary, so as to put it into communication with the pump chamber. The piston is connected to the push rod by a precompression spring which urges the piston towards a position in which said piston closes the lateral opening of the outlet channel.
When pressure is applied to the rod, it urges the piston towards the pump chamber via the precompression spring, thereby establishing suction in the pump chamber. As thrust on the push rod is increased, the pressure in the pump chamber increases and the precompression spring is compressed. When a predetermined pressure obtains in the pump chamber, the precompression spring is sufficiently compressed for the piston to release the lateral opening of the outlet channel and the substance contained in the pump chamber begins to be expelled.
If the user presses hard enough on the push rod, that type of pump functions well and produces a good spray. The predetermined pressure that obtains in the pump chamber during expulsion of the fluid normally gives said fluid a high flow speed giving rise to good spraying, generally via a spray nozzle in a pushbutton mounted on the push rod.
However, if the user presses lightly on the push rod, but just enough to create said predetermined pressure in the pump chamber, then the lateral opening of the outlet channel is not cleanly disengaged by the piston: as a result the fluid can flow therethrough only at a low rate. Since the outlet channel of the rod, and possibly also the spray nozzle, are dimensioned for a higher flow rate, the fluid flows through the outlet channel, and possibly also through the spray nozzle, at a speed that is too low to create a good spray.
SUMMARY OF THE INVENTION
An object of the present invention is to solve that technical problem.
The present invention thus provides a precompression pump comprising at least: pump body together defining a pump chamber; from the pump body, said push rod sliding axially in the center of the piston, said push rod including an outlet channel which opens out to the inside of the pump body via a lateral opening, the piston being displaceable relative to the push rod so as to close the lateral opening or so as to put into communication with the pump chamber; and and towards a rest position where it closes the lateral opening of the outlet channel; member displaceable with the push rod and situated axially between the piston and the pump chamber, and said central sealing member is in sealing contact with the piston when said piston is in its rest position, isolating the pump chamber from a central section of the piston.
In one embodiment, the piston includes an axial inside cylindrical surface open towards the pump chamber, said central sealing member sliding in sealed manner in said inside cylindrical surface while isolating the pump chamber from said central section of the piston, and said inside cylindrical surface extends axially towards the pump chamber over a length such that the central sealing member leaves said cylindrical surface when the piston has moved through a certain distance D2 relative to the push rod, starting from the rest position and going towards the outside end of the push rod.
Advantageously, the push rod includes at least one sealing zone situated axially at a location lying between the lateral opening of the outlet
REFERENCES:
patent: 5190192 (1993-03-01), Lina et al.
patent: 5482188 (1996-01-01), Lina
patent: 5562234 (1996-10-01), Su
Derakshanj Philippe
Valois S.A.
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