Metering valve for dispensing an aerosol
A metering valve for dispensing an aerosol, includes a metering chamber and a valve stem. The valve stem is equipped with one end disposed on the side of a container and a dispensing end mounted in the metering chamber such that it can slide under the force of a spring between a first high position, known as the rest position, and a second position, known as the intermediate position for filing the metering chamber. The metering chamber includes an upper cylindrical compartment and a lower cylindrical compartment, the diameter of the upper compartment being greater than that of the lower compartment.
1. A metering valve for dispensing an aerosol, comprising
a metering chamber, and
a valve stem provided with an end positioned on the side of a tank and a dispensing end and mounted to slide in the metering chamber under the effect of a spring, between a first top position, being a rest position, a second position, being an intermediate metering chamber filling position, and a third position, being a final bottom position, in which the spring is compressed, wherein, in the rest position, the metering chamber is isolated both from an outside of the valve and from an inside of the tank onto which the valve is fixed,
the valve stem comprising an expulsion orifice linking the metering chamber to the dispensing end when the stem is in the final bottom position, and a filling passage linking the tank to the metering chamber when the valve stem is in the intermediate filling position,
wherein the metering chamber comprises a top cylindrical compartment and a bottom cylindrical compartment, the diameter of the top compartment being greater than the diameter of the bottom compartment.
2. The metering valve for dispensing an aerosol according to claim 1 , in which the bottom cylindrical compartment and/or the top cylindrical compartment has a height in the axial dimension of the device lying between ¼ and ¾ of the total height of the metering chamber.
3. The metering valve for dispensing an aerosol according to claim 1 , in which the valve comprises a continuous annular aperture for the inlet of the aerosol into the metering chamber, the aperture being defined by the space between an inlet seal and the valve stem when the stem is in the intermediate filing position.
4. The metering valve for dispensing an aerosol according to claim 1 , in which, in the final bottom position of the stem, the spring is not completely compressed.
5. The metering valve for dispensing an aerosol according to claim 1 , in which a shoulder is formed at the interface between the two compartments, the final bottom position of the valve stem being defined by an abutment of a shoulder formed on the valve stem with the shoulder formed inside the metering chamber at the interface between the two compartments.
6. The metering valve for dispensing an aerosol according to claim 5 , in which the shoulder formed on the valve stem is borne by a protuberance also providing a function of abutment of the valve stem with a top wall of the metering chamber when the valve stem is in the rest position.
7. The metering valve for dispensing an aerosol according to claim 1 , in which the end of the valve stem comprises a first bearing surface against an inlet seal of the metering chamber ensuring a first sealing of the metering chamber with respect to the tank when the stem is in the rest position.
8. The metering valve for dispensing an aerosol according to claim 7 , in which the first sealing between the end of the stem and the seal is produced in the axial direction of the device.
9. The metering valve for dispensing an aerosol according to claim 1 , in which the valve stem comprises a second bearing surface against an inlet seal of the metering chamber providing a second sealing of the metering chamber with respect to the tank when the stem is in the final bottom position.
10. The metering valve for dispensing an aerosol according to claim 9 , in which the second sealing between the stem and the seal is produced in the radial direction of the device.