Patent Application
20060175570
A valve assembly, a pump for a viscous fluid, and an apparatus for dispensing fluids.
Valve assemblies for viscous fluid dispensers are known e.g. from international patent application WO 03/083334. This document discloses a valve assembly for a fluid dispenser including a housing having at least a first opening (19) and a second opening (20), and a valve member fitted in the housing, the valve member (15) being rotatable about an axis and comprising a first channel (22), extending along said axis and communicating with the first opening in the housing, and at least two outlet channels (23, 24) radially extending from the first channel to the circumference of the valve member, wherein each of the radially extending outlet channels can be brought in register with the second opening by rotating the valve member.
U.S. Pat. No. 6,595,240 relates to a three-way plastic diaphragm valve provided with a rather complicated creep compensation system, which compensates for compression of internal valve components as well as extension of the valve body. In a manually operated three-way valve embodiment of U.S. Pat. No. 6,595,240, a trapped spring mechanism inserted between an actuator portion and an upper valve member provides the closure force for the upper valve member on the upper valve seat. An example of the spring mechanism is shown in
An improved valve assembly is disclosed which comprises:
a housing and
a valve member mounted within the housing rotatable about an axis and between at least a dispensing position and a further position, for instance a volume selection position during which a material can be withdrawn from a container,
It is preferred that the housing comprises an opening, preferably an outlet opening or an opening communicating with an outlet, surrounded by a first seat and the valve member comprises at least one radially extending (outlet) channel, which can be brought in register with the opening by rotating the valve member, wherein the said spring urges the valve member against this seat.
It is further preferred that the housing comprises at least a second opening, preferably communicating with an inlet connected or connectable to a pump or a container, surrounded by a second seat, and wherein the valve member is clamped between the first and second seats by the said spring.
The disclosed valve assembly can be manufactured in part or entirely from one or more synthetic materials and hence is relatively inexpensive when compared to similar valve assemblies made of metal. Creep resulting from the use of synthetic material(s) is compensated for in an effective manner, which preferably allows a relatively straightforward and robust design of the valve assembly.
The disclosed valve a pump for a viscous fluids comprising the valve assembly described above and a pump mechanism associated with the said assembly.
Finally, the disclosed valve can be used in an apparatus for dispensing fluids, the comprises:
a turntable rotatable around an axis of rotation;
a plurality of pumps attached to and distributed around the axis of the turntable;
at least one of the pumps comprising a valve assembly described above.
The disclosed valve assembly, pump and apparatus will be further explained with reference to the accompanying drawings in which a presently preferred embodiment is shown schematically.
It is noted that the drawings are not necessarily to scale and that details, which are not necessary for an understanding of the disclosed valves, may have been omitted. As a matter of course, the disclosure is not limited to the particular embodiments illustrated herein.
This particular dispensing apparatus 1 includes a turntable 2, which is rotatable about a vertical axis by means of a drive (not shown) in order to rotate the turntable 2 between discrete positions. On the turntable 2, there are mounted a plurality of pumps 3, e.g., sixteen pumps. Each pump 3 is associated with a fluid container 4 comprising a replaceable flexible package (not shown) contained in a rigid, removable holder. When a flexible package is empty, the package and the holder containing it can be removed. Subsequently, the holder can be opened to take out the empty package and to insert a new, filled package, upon which the holder and the filled package can be placed back in the original position. Further details of the said apparatus are disclosed in U.S. Pat. No. 6,273,298, the contents of which are incorporated herein by reference.
FIGS. 2 to 4 show an embodiment of a pump 3 suitable for use in the apparatus of
The pump mechanism 5 is of the piston-type and includes a piston rod 7 provided with a piston 8 (see
The valve assembly comprises an upper housing 11, onto which the cylinder 9 is mounted, and a lower housing 12. The upper housing 11 defines a first cavity 13 that communicates with the cylinder 9 and an inlet channel 14 that is separated from the cavity 13 and adapted to be in fluid communication with a fluid container 4 as shown in
The lower housing 12 is snap-fitted to the upper housing 11 by means of a plurality of resilient fingers 15 (
At least the valve member 17 and the housings 11, 12 are made from a synthetic material, such as poly(oxymethylene) (POM), polyamide (PA or Nylon®) or polyethylene (PE), e.g. by means of injection molding. However, it is preferred that all parts described above are made from a synthetic material.
Further, it is generally preferred that at least one of the seats, preferably both, are curved and that the radius of curvature of the seat(s) is larger than the radius of the valve member, thus obtaining a tighter seal between the seat(s) and the valve member.
A helical spring 23, preferably made from a metal such as stainless steel (304 or 316) is located on top of the second seat 21, such that the valve member 17 is clamped between the two seats 19, 21, thus compensating for compression of internal valve components, in this example the seats 19, 21 and the valve member 17, as well as extension of the lower housing 12. The helical spring 23 is preferably positioned between guide members 23A. In an alternative embodiment, the membrane serves both as a seal and as a spring, obviating the need for a separate spring.
The valve member 17 includes first channels 24, extending along, i.e. co-axial with or parallel to, the axis A and discharging into the second cavity 16. It further includes an inlet channel 25 and an outlet channel 26, both radially extending from one of the first channels 24 to the circumference of the valve member 17. The valve member 17 can be operated by means a lever 27 (
As soon as an appropriate amount of fluid has been taken in, the valve member 17 is rotated to the dispensing position, i.e. until the outlet channel 26 is in registry with the outlet opening 18, which in this particular embodiment amounts to a rotation of respectively 50°, and the piston 8 is moved downwards to dispense the a desired amount of the fluid from the said opening 18.
The valve disclosed assembly is preferably made from one or more synthetic materials and hence relatively inexpensive when compared to valve similar valve assemblies made of metal. Creep resulting from the use of synthetic material is compensated for in an effective manner, allowing a relatively straightforward and robust design of the valve assembly.
The valve assembly is not restricted to the embodiment shown in the drawing and described herein before. For example, the valve member can be provided with two or more outlet channels having different diameters, so as to facilitate dispensing different (larger and smaller) volumes. Also, the valve assembly can be mounted directly onto or into (the bottom part of) a container, i.e., without the presence of a pump mechanism.
As a matter of course, this disclosure is not restricted to the above-disclosed embodiment and can be varied in numerous ways still falling within the scope of the appended claims. For instance, the spring can be located inside the valve member urging it to expand or could take the shape of a resilient bracket mounted about at least the valve member and the housing thus urging the same together.
