DISPENSING VALVE FOR VISCOUS PRODUCTS

Abstract: A valve member (1c) is movable with a hollow stem (1) to an opening position (not shown) in which the product flows under pressure past the valve member (1c), through a valve seat (2c) and through the stem (1). A spring (3) with resiliently bendable legs (3a), urges the stem (1) to the closing position (shown).

Description: Dispensing Valve for Viscous Products This invention relates to a valve for dispensing a flowable product under pressure, in particular a viscous product. Conventional dispensing valves used on pressurised containers (e.g. so-called aerosol cans) provide narrow passageways for the product and are unsuited to viscous products. They also have internal moving parts which do not operate effectively in viscous media. Furthermore, the conventional valves use seals which may be adversely affected by the product, which may contaminate the product, and which may be degraded by extremes of temperature during storage, e.g. in a freezer. What is desired is a dispensing valve which is easy to manufacture and which can effectively dispense viscous products under pressure. The invention provides a valve with a hollow stem carrying a valve member cooperating with a valve seat, the valve being opened and closed simply by longitudinal movement of the stem. In particular, the invention provides a valve for dispensing a flowable product from a container under pressure, comprising: a hollow stem extending through a container closure member and being axially movable; a valve seat provided inside the container closure member, the seat defining an aperture aligned with the stem; a valve member connected to the stem, the valve member being movable with the stem from a closing position, in which the valve member cooperates with the seat to close the aperture, to an opening position, in which the valve member is spaced axially inwards from the seat so that the product can flow past the valve member, through the aperture and through the hollow stem; and spring means for urging the valve member and the stem from the opening position to the closing position. The invention will be described further, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is an axial section through a dispensing valve, in a first embodiment; Figure 2 is an axial section through a dispensing valve, in a second embodiment; Figure 3 is an axial section through a dispensing valve, in a third embodiment; Figure 4 is similar to Figure 3, but with the valve open; and Figure 5 is an axial section through a mounting cap of the third embodiment, on a reduced scale; and Figure 6 is an axial section through a dispensing valve, in a fourth embodiment. The dispensing valve shown in Figure 1 comprises a container closure member in the form of a sheet-metal cap 4 which is to close one end of a can for containing a viscous product which is pressurised, e.g. by a compressed gas (mixed with or isolated from the product). The cap 4 has a peripheral sidewall 4a with a bent-over flange 4b which fits over the rim of the can. (In this example, crimping jaws are lowered inside the peripheral sidewall 4a and expanded to connect the sidewall 4a to the wall of the can.) The cap 4 has a central neck 4c and a base 4d, which in this example slopes down from the neck 4c to the sidewall 4a. A moulded plastics guide member 2 is inserted into the neck 4c from the inside (underside) of the cap 4 and is retained there by a protruding peripheral ring 2a engaging the upper end of the neck 4c outside the cap 4. The radially outer surface of the guide member 2 is in intimate contact with the radially inner surface of the neck 4c, to seal against leakage. Sealing is enhanced by an integral lip 2b adjacent the vmderside of the base 4d. Furthermore, the inside (underside) of the cap 4 may be lined with plastics material (e.g. polypropylene or polyethylene), to enhance sealing and to isolate the sheet metal from the product. The guide member 2, inside (under) the cap 4, has an integral valve seat 2c defining an aperture 2d, which in this example is an axially inward (downward) continuation of the radially inner surface 2e of the guide member 2 and which widens in the axially inward (downward) direction, in a smoothly curved manner in this example. A hollow stem 1, in the form of a cylindrical tube, is fitted closely in the guide member 2 so as to be freely axially slidable. The stem 1 defines an unobstructed passageway la for the product, extending from an axially inner (lower) end inside the cap 4. A suitable dispensing nozzle may be fitted on the outer end of the stem 1. To enhance resistance to leakage, the stem 1 has an integral peripheral lip lb (or lips) providing a type of labyrinth seal. At the inner (lower) end of the stem 1 there is an integral base constituting a valve member lc which fits in the aperture 2d of the valve seat 2c and which has a peripheral lip Id extending radially outwards and axially inwards (downwards), for making good sealing contact with the inside (underside) of the guide member 2. Adjacent the valve member lc the hollow stem 1 has lateral ports If whose total flow cross-section is equal to or, preferably, greater than the flow cross-section of the passageway la. When the stem 1 is pushed axially inwards (downwards) from the closing position shown, the valve member lc leaves the aperture 2d and becomes spaced axially inwards (downwards) from the seat 2c, until the ports If are no longer covered by the radially inner surface 2e of the guide member 2. In this opening position the product, under pressure in the can, flows out past the valve member lc, through the aperture 2d, the ports If, and the passageway la. The stem 1 is urged from the opening position to the closing position by a spring 3 which interacts with a reaction member 5. The spring 3 comprises a ring of resilient plastics material (e.g. acetal or POM) which is an interference fit on the stem 1 and which has integral resiliently bendable legs 3a extending towards the reaction member 5 (e.g. 8 legs wider than the spaces between them). The spring 3 is positioned such that when it abuts against the outer (upper) end of the guide member 2 (when the stem 1 is depressed) the ports If are fully open. The reaction member 5 is in the form of a fhistoconical collar with inner stiffening ribs 5a and an outer surface 5b sloping downwards and outwards (at about 30° to the axial direction in this example). As the stem 1 is depressed, the rounded free ends 3b of the legs 3a slide down the sloping surface 5b so that the legs 3a are splayed outwards. The second embodiment shown in Figure 2 omits the collar 5, and the legs 3 a are extended so as to interact with a sloping reaction surface constituted by the outer surface of the base 4d of the cap 4. Figures 3 to 5 show a third embodiment, which is similar to the second embodiment (Fig. 2) and which has a modified cap 4, the reaction surface having a steeper slope (40° to the axial direction). In Figures 3 and 5 dimensions in millimetres are given by way of example. Figure 5 shows a fourth embodiment which is similar to the first embodiment except that the spring 3 and the reaction member are provided inside (under) the cap 4. The spring 3 is integral with the valve member lc and has four equally spaced legs 3a projecting axially downwards away from the valve member lc. When the stem 1 is depressed, the free ends of the legs 3a slide down the sloping outer surface 5b of a generally fhistoconical plug 5c which is formed on a spider 5d made of plastics material and fixed to the lower end of the guide member 2. An advantage of this arrangement is that it increases the space available for inserting crimping jaws inside the peripheral sidewall 4a of the cap 4. Furthermore, since the valve member lc extends radially outwards beyond the radially inner surface 2e of the guide member 2, the stem 1 cannot be forced out of the guide member 2 by the pressure of the product. The above-described valves allow a wide range of viscous products to be dispensed, including greases, cosmetic products such as creams and gels, and food products such as cream, cream cheese, and other milk products. The product may be mixed with a pressurised propellant or may be contained in a bag compressed by a propellant. Alternatively, the product may be put under pressure by a piston driven by any suitable means, e.g. by compressed gas or even manually. The valves described above consist of only 3 or 4 separate parts. They are easy to manufacture. Rubber seals are not required. The only moving parts in contact with the product are made of plastics material (and the connection between them). There is minimal obstruction to the flow of product. The internal diameter of the hollow stem is preferably at least 8 mm and may be as much as 12 mm. All the parts of the valve which come into contact with the product can be made of materials which do not degrade the product, are not themselves degraded by the product, and withstand extremes of temperature. It will be appreciated that various modifications may be made in the above- described valves within the scope of the invention. For example, the valve member may be arranged entirely below the valve seat. The valve member may be connected to the stem other than by the sidewall portions between the lateral parts, e.g. by a spider and a central post. The preferred number of legs is 3, 4, 6, or 8. the legs being equally spaced circumferentially; however, the spring could be made to work with two legs or even only one leg. The legs could be replaced by an apron or skirt (which may be slit or slotted) or by a bellows. The spring may be made of metallic material instead of plastics material, in order to permit the maximum range of storage conditions. A compression spring (e.g. a helical spring) could act between the cap and a collar fixed or formed on the stem. Although the valves are primarily intended for use with viscous products, they may of course be used with other liquid products.

Claims: CLAIMS: 1. A valve for dispensing a flowable product from a container under pressure, comprising: a hollow stem (1) extending through a container closure member (4) and being axially movable; a valve seat (2c) provided inside the container closure member (4), the seat (2c) defining an aperture (2d) aligned with the stem (1); a valve member (lc) connected to the stem (1), the valve member (lc) being movable with the stem (1) from a closing position, in which the valve member (lc) cooperates with the seat (2c) to close the aperture (2d), to an opening position, in which the valve member (lc) is spaced axially inwards from the seat (2c) so that the product can flow past the valve member (lc), through the aperture (2d) and through the hollow stem (1); and spring means (3) for urging the valve member (lc) and the stem (1) from the opening position to the closing position. 2. A valve as claimed in claim 1, in which the valve member (lc) fits in the aperture (2d) defined by the seat (2c). 3. A valve as claimed in claim 1 or 2, in which the hollow stem (1) has lateral ports (If) adjacent the valve member (lc), the total flow cross-section of the ports (If) preferably being at least equal to the flow cross-section of the hollow stem (1). 4. A valve as claimed in any of claims 1 to 3, in which the hollow stem (1) is axially slidably mounted in a guide (2) which is mounted in and extends through the closure member (4). 5. A valve as claimed in claim 4, in which the valve seat (2c) is integral with the guide (2). 6. A valve as claimed in claim 4 or 5, in which the stem (1) makes direct sealing contact with the guide (2). 7. A valve as claimed in any of claims 1 to 6, in which the spring means (3) comprises at least one resiliently bendable element (3a) carried by the stem (1). 8. A valve as claimed in claim 7, in which the bendable element (3a) has a free end slidably restmg on a reaction surface (5b) extending obliquely radially outwards and axially. 9. A valve as claimed in claim 7 or 8, in which at least three said bendable elements (3a) are equally circumferentially spaced around the axis of the stem (1). 10. A container provided with a valve according to any preceding claim, in particular containing a viscous product.

Inventors: BELAU RUEDIGER, BELAU, RUEDIGER
Applicants: BELAU RUEDIGER, LINDAL VALVE CO LTD, BELAU, RUEDIGER, LINDAL VALVE COMPANY LIMITED
Application year: 1998
Main classification: B65D83
IPC codes: B65D83