This invention relates to a fibre wound vessel comprising a plastics container for holding liquid and/or gaseous substances, if desired under pressure, and a collar associated with the plastics container to which a release mechanism can be attached for dispensing the liquid and gaseous substances.

Background to the invention

Certain substances need to be kept within a sealed environment prior to use and vessels comprising a fibre wrapped plastics container are of particular benefit in retaining such substances as the plastics material is not subject to corrosion and the fibre wrap strengthens the plastics container. The vessel is associated with a discharge or release mechanism which seals the container and provides a controlled release of the vessel contents which can be in the form of liquid, powder and/or gas. Controlled release is particularly important where the substances are kept under pressure or are pressurised as they are discharged. However, it is difficult to secure the release mechanism to the fibre wrapped plastics container.

Summary of Invention

In accordance with the present invention, there is provided a vessel comprising a plastics container with an upstanding neck around which is located a collar, to which is typically attached a release mechanism for dispensing substances such as liquids, powders and/or gases from the container, wherein the collar comprises at least one uni-directional engagement member, such as a barbed element, which engages with the container to prevent removal of the collar. This ensures that the collar is permanently fixed and locked in place preventing release of the collar and inadvertent uncontrolled release of substances within the container.

Preferably the at least one one uni-directional engagement member is located on an internal face of the collar so as to engage with the neck of the container. A plurality of uni-directional engagement members may be provided, preferably circumferentially spaced around the internal face of the collar. Thus if removal of the collar is attempted, the collar resists removal through the uni-directional engagement members engaging the upstanding neck at a number of positions.

Typically the neck of the plastics container will have an external thread and where this is so, preferably the collar further comprises a co-operating internal thread. In such embodiments, the co-operating screw threads of the container and the collar allow the collar to be screwed in one direction onto the neck, with the at least one unidirectional engagement member or plurality of unidirectional engagement members resisting removal and preventing the collar being screwed off in the opposite sense, the uni-directional engagement member(s) digging into the neck to prevent the collar being unscrewed.

Preferably the uni-directional engagement member is a barbed element.

The collar may have a flange extending from its base with a shoulder of the container having a complementary shaped seat into which the flange locates. During positioning of the collar on the container, it is easy to tell once the collar is properly secured as at that point the flange will sit securely in the seat.

Desirably the collar is made from metal and is of preference made from brass or other easily machinable metal. This ensures that release mechanisms can be connected securely to the internal surface of the container neck and to the external surface of the collar.

Typically the collar will have an external thread for receiving at least part of a release mechanism with a complementary internal thread. The neck of the container may have an internal thread for similarly receiving at least part of a release mechanism. The neck may incorporate a grooved annulus for receiving a seal such as an o-ring, this ensures that a pressure-tight seal is provided.

Such vessels may be pressure vessels capable of containing pressurised substances at greater or less than ambient pressure, examples of which include fire-extinguishers, gas containers, hot water cylinders and air brake accumulators. The invention will now be described, by way of example and with reference to the accompanying drawings in which:

Figure 1 is a sectional view of a vessel in accordance with the present invention, the vessel comprising a plastics container and a collar;

Figure 2 is a perspective view of the collar positioned on the container;

Figure 3 is a side view of the collar positioned on the container;

Figure 4 is a section on line IV-IV shows a locking mechanism associated with the collar;

Figure 5 is an underside view of the collar; and

Figure 6 is a sectional view of the container.

Description

A vessel in accordance with the present invention is shown in Figure 1. The vessel 10 comprises an inner container 12 made from blow-moulded or rotation-moulded plastics material within which are substances such as liquids, powders and/or gases. A metal collar 14 is screwed onto a neck 13 of the container 12 and attached to both the container 12 and collar 14 is a release mechanism 16 for dispensing the pressurised contents of the container, and which, if desired, has a pressure gauge 17. A fibre wrap 18 surrounds the container 12 and if required is in turn encompassed by a protective sleeve or coating 20. As will be understood by those in the art, the release mechanism 16 is shown by way of example, there being a number of different types of release mechanism available depending on the substance held in the vessel.

The fibre wrap 18 is flexibly adhered to the container 12 in a complex interlocking weave pattern so as to flexibly encase the container 12 and strengthen the container such that it can resist deformation from internal pressures if present. The container can hold non-pressurised substances, pressurised substances in the range greater than 0 to 900 bar or substances that are pressurised before or upon discharge. Thus, by way of example, the container can be used for fire extinguishers with pressures around 6 bar, gas containers, hot water tanks and air brake accumulators. The fibre wrap 18 also strengthens the plastics container against externally applied forces. Thus the container 12 has the ability to be crushed and maintain its structural integrity without breaking or rupturing, the plastics container restoring its original shape over time once the crushing force is removed. The container is thus able to comply, where required, with regulations relating to crush resistance.

The brass collar 14 is shown positioned on the container 12 in Figures 2, 3, and 4 and an underside view of the collar 14 on its own is shown in Figure 5. The collar 14 comprises an upstanding neck portion 26 and a flange 28, the flange angled so as to conform to the angle of a lipped seat 24 formed in the shoulder of container 12, see Figure 6. The neck portion 26 is internally and externally threaded, with a locking mechanism 30 provided at the lowermost part of the internal face of the neck portion 26, the locking mechanism 30, see Figures 4 and 5, comprising a plurality of circumferentially equispaced barbs 32 being substantially triangular in shape. An internal thread 34 of the collar or locking ring 14 is dimensioned to engage with an externally threaded neck 13 of the plastics container 12. The mating threads of locking ring 14 and container 12 engage as the locking ring 14 is turned in one direction, typically clockwise, with the ring 14 screwed down until the flange 28 sits firmly within its seat 24, this indicating to a party assembling the vessel that the locking ring 14 is correctly positioned.

As the locking ring 14 is turned in one direction to screw down onto the container neck 13, the barbs 32 are angled such that they ride over the neck 13 of the bottle and do not engage, so not interfering with the screwing motion. However the barbs 32 are uni-directional such that if one attempts to turn the locking ring 14 in the opposite direction, typically counter-clockwise, the upstanding edge of the barb 32 bites into the plastics neck 13 and prevents the collar 14 being twisted in an upwards direction. In this way one can screw the collar 14 onto the neck 13, the collar 14 twisting downwardly freely until it is engaged with the seat 24, but if attempting to reverse the direction of travel, the barbs 32 engage with the neck portion 13 and prevent upwards movement. The locking ring 14 thus secures to the plastics container 12 in a manner which is permanently locked in place due to the engagement of the barbs. After the brass collar 14 is screwed onto the container 12, flexible waterproof solvent- free adhesive is applied to the container 12 and the fibre wrap 18 formed from Aramid fibres or similar wound round and flexibly adhered to the container 12 in a complex interlocking weave pattern where the orientation and layering of the fibres is selected. The adhesive permeates the wrap fibres layered above it and creates a permanently flexible bond that ensures the fibres are kept in the correct orientation as required by the weave pattern whilst still being able to flex with any deformation of the container. The fibre wrap 18 is wound over the flange 28 of the locking ring 14, leaving the outer threaded portion 26 of the collar 14 free for a release mechanism 16 to thread onto. The fibre wrap 18 reinforces the plastics container so that it can resist internal pressures and can resist compression or crushing forces applied externally.

The fibre wrap 18 is, if required, protected with a rigid sleeve or protective coating.

The neck 13 of the plastics container is typically provided with an inner groove in which an o-ring 36 will seat to ensure that the discharge mechanism 16 and container 12 are in completely sealed engagement.

If necessary the discharge mechanism 16 can be removed by skilled personnel using appropriate tools, with safety features within the mechanism 16 ensuring that a controlled safe discharge of the contents occurs as removal takes place. However the mechanism 16 cannot be removed in a manner which bypasses such safety features as the collar to which it attaches is permanently fixed to the container 12 and cannot be removed unless the plastics container is melted down at high temperature. This ensures that substances cannot be released by bypassing the safety features within the discharge mechanism which is particularly important where the vessel contains pressurised substances in the form of gases and/or liquids such as those used in fighting fires or will contain toxic substances.