Dispensing – With discharge assistant – Fluid pressure
Patent
1991-06-25
1992-10-27
Kashnikow, Andres
Dispensing
With discharge assistant
Fluid pressure
222399, G05D 1606
Patent
active
051582155
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to an automatic lift valve for a container containing a pressurized creamy or liquid product, comprising a valve body comprising a cylindrical chamber provided at one of its ends with an outlet aperture, a valve seal closing, in the position of rest, said outlet aperture and being solidly fixed to a piston rod which itself is solidly fixed to a piston fitted with a ring and capable of moving in a bore, a spring working in compression between said piston and the other end of said chamber and so maintaining the valve seal against the outlet aperture, the space of the chamber containing the spring communicating with the exterior.
PRIOR ART
Lift valves of this type are described in international patent application WO 86/04,163. In these prior lift valves, the fluid passes through a longitudinal groove made in the wall of the bore, under the O-ring gasket forming the ring of the piston. According to one embodiment, the lift valve comprises two pistons fitted with piston rings, which requires a relatively long precision bore which is difficult to produce, particularly when the lift valve is made from injection-molded synthetic material. According to another embodiment comprising only one piston provided with a piston ring, and consequently able to operate with a short bore, the chamber is formed by a plurality of parts. Moreover, the groove, situated at the bottom of the bore, requires special means in order to obtain it.
SUMMARY OF THE INVENTION
The object of the present invention is to produce an automatic lift valve of simpler design which is consequently easier to manufacture and less expensive.
The automatic lift valve according to the invention comprises a cross-section reducer ring which is solidly fixed to the piston rod, between the piston and the valve seal, and a lateral inlet aperture situated between the piston and the cross-section reducer ring, close to the cross-section reducer ring, in a manner such that said ring can at least partially cover the inlet aperture during the movement of the piston toward the spring under the action of the pressurized product.
The cross-section reducer ring may be formed by a cylindrical bearing surface pierced by holes parallel to the axis. The cross-section reducer ring must be able to move freely in the chamber and does not require to be adjusted in the manner of a piston. Only the part of the cylindrical chamber in which the piston, provided with the piston ring, moves has to be produced in a perfectly smooth precision manner.
The cross-section reducer ring may be formed, for example, by a cylindrical bearing surface of the piston rod pierced by holes parallel to the axis. When the pressurized creamy or liquid product arrives in the chamber, between the piston and the cross-section reducer ring, it exercises an equal pressure on the piston and on the reducer ring but, since part of the product can pass through the cross-section reducer ring, the pressure on the reducer ring immediately drops and the piston retracts, thus opening the lift valve.
Operating without a resilient seal for the passage of the product, the lift valve according to the invention is particularly well suited to the distribution of liquid products of a certain viscosity, and creamy products.
BRIEF DESCRIPTION OF THE DRAWINGS
The attached drawing shows, by way of example, an embodiment of the invention and several variations thereof.
FIG. 1 is a view in axial section, in the position of rest, of an automatic lift valve according to the invention fitted to a container containing a pressurized product.
FIG. 2 is an analogous section showing the lift valve in the opening position
FIG. 3 is a sectional view along III--III in FIG. 1.
FIG. 4 is a first variation of this section.
FIG. 5 is a second variation of this section.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The automatic lift valve shown in FIG. 1 comprises a body 1 of generally conical exterior shape, containing a cylindrical chamber 2 having an outlet aperture 3 at its upper
REFERENCES:
patent: 4519528 (1985-05-01), Comment
DeRosa Kenneth
Kashnikow Andres
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