Known designs of tap suffer from various disadvantages. A common design of tap includes a screwable spindle having a washer which is engageable with a seat in the tap body.

The degree of movement of the spindle determines the flow of fluid through the tap. Another type of tap referred to as a swivel ball joint comprises a tap body in the form of a pipe in which there is provided a rotatable ball having a hole therein such that flow is permitted when the ball is rotated by a quarter turn and the hole is aligned with the pipe. Another type of tap comprises a spindle having thereon a ceramic disc on which engages with a seating. A quarter turn of the spindle which has a wide thread causes the disc to seat/unseat thereby closing or opening the tap.

These designs of tap are expensive and complicated to manufacture because of the relatively large number of parts, which furthermore must be accurately machined.

Moreover, because of the relatively complex construction of these designs, there exists a greater chance for faults and correspondingly there is a need for a relatively high degree of maintenance. Known taps may also be over- tightened making them difficult to open again. A further disadvantage of the spindle taps is that the taps may not be quickly changed from their fully closed position (no flow) to their fully open position (fluid flowing) as may be required when a flow is needed in an emergency, e. g. in

a firefighting situation. A further disadvantage of the ball joint taps is that the taps may seize. A further disadvantage of the ceramic disc taps is that if the water system becomes contaminated with particulate matter, e. g. grit or other debris, such matter may become lodged between the ceramic disc and the seating and may cause cracking of the disc.

GB 787754 describes a tap comprising a hollow inner plug having a discharge aperture, about which is telescopically mounted an outer body, the outer body also having a discharge aperture, wherein the inner plug and outer body may be slidably adjusted between a position where the apertures are aligned and hence the tap is open and a position where the aperture of the plug is closed by the wall of the outer body. However, the construction of the tap, including the sealing arrangement, is such that the tap is usable in only one direction without leakage and the tap may be prone to leakage during the opening or closing operation.

It is an aim of the invention to provide an improved tap in which the aforementioned problems are overcome or reduced.

According to the invention there is provided an assembly comprising a first hollow member for carrying a fluid having at least one aperture in a wall thereof for fluid flow thereacross and a second hollow member having at least one aperture in a wall thereof for fluid flow thereacross, the second member being slidably mounted about the first

member, and wherein one of the members is provided with a spaced apart pair of annular seals to seal between the first and second members, the pair of spaced apart annular seals being located on the member to the same side of the at least one aperture in the member, the assembly being adjustable by relative sliding movement of the first and second members in an axial direction between an open position where the at least one apertures of the respective members are in fluid communication with each other thereby to allow flow of fluid between the members and a closed position where the at least one aperture of one member is closed by the wall of the other member and sealed on either side by the pair of annular seals in the other member.

The first and second members are hollow members. In one embodiment, each member preferably comprises a generally tubular form. In principal, the members may comprise any cross sectional shape, e. g. circular.

The members are slidable in an axial direction, i. e. a direction along the length of the members. The second member is slidably mounted about the first member, i. e. the second member is the external member and the first member is the internal member. For example, the second member may be concentrically mounted about the first member. The members are thus telescopically slidable. For this, the external member has an internal diameter slightly larger than the external diameter of the internal member in order to be mounted thereabout. The term diameter herein includes reference to any shape, including other than circular.

Diameter thus means generally the measurement across a member.

The pair of seals may be located on the internal diameter surface of the second member. Alternatively, the pair of seals may be located on the outer surface of the first member.

Preferably, the at least one aperture in the first member comprises at least one hole in the wall of the member, more preferably a plurality of holes. In one preferred embodiment, the first member is provided with a pair of such holes approximately diametrically positioned with respect to each other. In another preferred embodiment, the first member is provided with a plurality of diametrically positioned pairs of holes, e. g. two or three such pairs.

Advantageously, the assembly enables fluid flow in either direction, i. e. from the first member to the second member or from the second member to the first member, without leakage. Furthermore, the assembly does not leak in any position or during movement between positions. The design is very simple, has few parts and requires little or no maintenance.

In a preferred embodiment, the second member may have an, e. g. tubular, outwardly extending portion extending from the at least one aperture therein, e. g. at right angles to the remainder of the member.

The pair of seals provide a fluid seal between the first and second members. Preferably, the seals permit relative sliding movement of the members. The seals are spaced apart in an axial direction. Preferably, the seals comprise 0- rings. Preferably, the seals are held in recesses provided in the surface of the second member to positively retain the seals. The seals enable the assembly to withstand high fluid pressure without leakage. The seals are both located on the same side of the at least one aperture of the member. The seals define between them a portion or region of the member wall which can close the at least one aperture of the other member.

Preferably, in one type of embodiment the second member is closed or closable at one end to contain the fluid in a path between the apertures of the first and second members in the open position. For example, the end may be closed by a removable cap, e. g. a screwable cap, which compresses a, e. g. o-ring, seal therebetween. The closable end may be opened to permit insertion of the first member and be closed to prevent removal in use. The closed end may also restrict relative travel of the first member in the direction of that end.

Alternatively, or additionally, to the closed or closable end, in another type of preferred embodiment, there may be a further seal on the other side of the aperture to the pair of seals to seal between the second member and first member. The further seal spaced apart from the pair of seals may define therebetween a second portion or region

for constraining the fluid to flow between apertures of first and second members when the assembly is in the open position.

Preferably, the assembly includes means to restrict the relative travel of the members. Such means may include one or more projections on the surface of the first member, preferably at or near the end thereof. Such means may take the form of an enlarged diameter end portion on the first member such that a step is thereby provided on the outside of the first member between the enlarged diameter portion and the smaller diameter remainder of the member which step can engage a part of the second member to prevent the further movement of the second member in the direction of the enlarged end. The means may take the form of a suitable circumferential flange at or near the end of the first member.

The assembly in accordance with the invention comprises relatively few and simple components which makes the assembly cheap and easy to manufacture. The components do not have to be machined to high tolerances as sealing is effected between them. Furthermore, because of the relatively simple construction of the assembly, the tap is reliable and requires little maintenance. Furthermore, because the assembly operates by simple sliding movement of the components, the tap may be switched from the open to closed position and vice versa quickly and easily.

In one embodiment, one of the members, e. g. the first member, may have one end engageable with an item of equipment supplying fluid, eg a hose, another pipe or a hydrant, for fluid communication therewith. The other member, e. g. the second member, thereby provides the outlet of the tap. The outlet of the other member may also be engageable with a further item, e. g. to supply another pipe.

The tap may be constructed of any suitable material, for instance plastics or brass.

The assembly may be provided in different sizes, e. g. for use in connection with different standard sizes of hose or pipe such as 3 or 5 inch.

An example of the invention will now be described in detail with reference to: Figure 1 which shows, in longitudinal section, an embodiment of an assembly in accordance with the invention in the closed position; Figure 2 which shows, in longitudinal section, the embodiment of assembly of Figure 1 in the open position ; Figure 3 which shows, in longitudinal section, a further embodiment of an assembly in accordance with the invention; Figure 4 which shows, in longitudinal section, another embodiment of an assembly in accordance with the invention in the closed position;

Figure 5 which shows, in longitudinal section, the embodiment of assembly of Figure 4 in the open position; and Figure 6 which shows, in perspective view, an embodiment of first member for use with an assembly in accordance with the invention.

Referring to Figure 1, there is shown an assembly 1 in accordance with the invention in closed off position. The assembly comprises a first member 2 which is of generally tubular form. The first member 2 has a closed end 6 and an open end 8. The external surface of the first member at the open end 8 is provided with a screw thread 10 for engagement with a corresponding screw thread on an item of water supplying equipment, e. g. back plate or a stand pipe.

The first member 2 has an end portion 12 of slightly larger external diameter. The first member 2 is provided with two holes 14 positioned diametrically to each other. The holes 14 are provided conveniently by drilling through both sides of the first member.

Mounted slidably in the axial direction indicated by arrow B on the outside of the first member 2 is a second member 4. The second member 4 comprises a generally tubular form body 16 which slidably fits about the first member 2. The tubular body 16 has open ends to permit the second member 4 to be slipped over the first member 2. The second member 4 also has a tubular outlet portion 18 extending at right angles to the tubular body 16. An aperture 20 is provided

in the second member 4 where the outlet 18 joins the tubular body 16. As can be seen in the Figure, the tubular body 16 has an enlarged diameter portion 29 to which the outlet 18 is joined and which in the closed position of Figure 1 seals against the enlarged diameter part 12 of the first member 2 and a smaller diameter portion 28 which seals against the remainder of the first member 2.

The second member 4 has a screw thread 22 on the end of the outlet 18 to enable the outlet to be connected to an item of equipment if desired, eg a hose.

The second member 4 is provided with annular recesses 24a, b, c. The recesses 24a, b, c accommodate O'rings 26a, b, c. The O'rings 26a, b, c provide seals between the second member 4 and the first member 2. The rings 26a and 26b, positioned on either side of the aperture 20 of the second member 4 define a first portion of the second member therebetween. The ring 26b and the 0'ring 26c spaced longitudinally therefrom at the end of the tubular body 16 define a second portion of the second member 4 therebetween.

It can be seen from Figure 1, with the first and second members arranged as shown, that a flow of fluid as indicated by arrow A cannot pass through the two apertures 14 since the apertures 14 are closed by the second portion of the second member 4. The rings 26b and 26c on either side of the apertures 14 prevent fluid leakage.

Referring to Figure 2 there is shown the assembly 1 in its open position. The second member 4 has been slid axially along the first member 2 from the position shown in Figure 1 to the position shown in Figure 2. The sealing means 26a, b, c permit sliding movement between the second member 4 and the first member 2.

The second member 4 is positioned in Figure 2 such that the first portion of the second member 4, defined between 0' rings 26a and 26b, is now aligned with the apertures 14 in the first member 2, with the rings 26a and 26b on either side of the apertures 14 to seal on either side thereof. It can be seen that a flow of fluid in the direction of arrow A may pass through the apertures 14 in the first member 2 and thereby through the aperture 20 in the second member 4 and thereafter through the outlet 18.

By virtue of the larger diameter portion 29 of the tubular body 16, an annular space 30 is provided, in the tap's open position, about the first member 2 adjacent the apertures 14 which provides a further path for the fluid flow around the member 2 from apertures 14 to the aperture 20.

It can be seen from Figures 1 and 2 that the movement of the second member 4 further in the direction of the closed end 6 of the first member 2 is prevented by virtue of the enlarged external diameter portion 12 on the first member 2. In particular, the inner radial surface 34 of the second member 4 at the transition between the tubular portions 28 and 29 thereof abuts the shoulder 32 of the enlarged diameter portion 12. Thereby, the second member 4 is held

on the first member 2. In addition the travel of the second member 4 further in the direction of the threaded end 8 of the first ember beyond that shown in Figure 2 is prevented by the presence of the back plate etc. to which the threaded end 8 is connected in use.

Referring to Figure 3, there is shown a further embodiment of assembly according to the invention. The assembly is substantially similar to the embodiment shown in Figures 1 and 2 with the following difference. In this case, the first member 2 does not have an enlarged diameter end portion as in Figures 1 and 2 which in the closed position resides inside the second member 4. Instead the first member 2 is substantially the same diameter along its length except for a circumferential outwardly extending flange 3 at its end remote from its threaded end.

Similarly, the tubular body 16 of the second member 4 is substantially the same diameter along its length. The internal diameter of the tubular body 16 is less than the outer diameter of the flange 3. Thereby, in use, the second member 4 is prevented from being removed from the end of the first member 3 by virtue of the end of the tubular body 16 abutting the flange 3 as shown.

Referring to Figure 4, there is shown an assembly, similar to that shown in Figures 1 to 3, in accordance with the invention in closed off position. The assembly comprises a circular cylindrical first member 2 which is of generally the same form as first member 2 shown in Figure 3,

including having outwardly extending flange 3 at its closed end.

Mounted slidably in the axial direction on the outside of the first member 2 is second member 4. The second member 4 comprises a generally tubular form body 16 into the bore of which slidably fits the first member 2. The bore of second member 4 has an enlarged diameter chamber 60 which accommodates flange 3 of the first member. A smaller diameter section accommodates the remainder of the body of the first member. The tubular body 16 has a closable end 42. The mouth of closable end 42 is internally threaded with thread 46 and is closed by end cap 44 which has an externally threaded portion 48 for threaded engagement with thread 46 of the second member. Cap 44 has a radially extending hexagonal nut portion 54 for tightening the cap.

The cap 44 carries an o-ring 52 which is compressed between the end of the second member and the nut portion 54 of the cap 44. The end 42 of the second member is thus provided with a fluid-tight seal.

The first member 2 is inserted into the second member 4 when its end 42 is open (i. e. with cap 44 removed). First member 2 can be inserted until its flange 3 abuts radial shoulder 62 in the bore of the second member 4.

The second member 4 has an aperture 20 forming an outlet channel 18 extending at right angles to the tubular body 16. The channel 18 has internally threaded section 22 into

which may be screwed a pipe, hose pipe fitting or other item (not shown).

The second member 4 is provided on the side of aperture 20 opposite to the side with closable end 42 with spaced apart annular recesses 24a, b. The recesses 24a, b accommodate 0' rings 26a, b. The O'rings 26a, b provide seals between the second member 4 and the first member 2. The spaced apart 0'rings 26a and 26b, positioned on the same side of the aperture 20 of the second member 4 define a portion 58 of the internal wall of the second member 4 which, in the position shown, closes the apertures 14 of the first member 2.

It can be seen from Figure 4, with the first and second members arranged as shown, that a flow of fluid as indicated by arrow A cannot pass through the two apertures 14 since the apertures 14 are closed by the portion 58 of the second member 4 as sealed by the rings 26a and 26b on either side of the apertures 14 prevent fluid leakage.

Referring to Figure 5 there is shown the assembly of Figure 4 in its open position. The second member 4 has been slid axially along the first member 2 from the position shown in Figure 4 to the position shown in Figure 5. The sealing means 26a, b permit the sliding movement between the second member 4 and the first member 2.

The second member 4 is positioned in Figure 5 such that the aperture 20 of the second member 4 is aligned with the

apertures 14 in the first member 2. O'ring 26a seals on one side of the apertures 20 and 14 and the other side is sealed by means of the closed end 42. It can be seen that a flow of fluid in the direction of arrow A may pass through the apertures 14 in the first member 2 and thereby through the aperture 20 in the second member 4 and thereafter through the outlet 18. Equally, it is possible for the flow of fluid to be arranged to flow from section 18, through aperture 20 in the second member 4 and then through apertures 14 in the first member 2, i. e. in the reverse direction to arrow A in Figure 5.

Movement of the first member 2 further in the direction of the closed end 42 of the second member 2 is prevented by abutment with the end cap 44. In the other direction, the inner radial surface 62 of the second member 4 at the transition between the enlarged chamber 60 and the smaller diameter bore section abuts the flange 3 of the first member to restrict further movement of the first member.

It will be appreciated that the seals may, alternatively, be provided in the first member Referring to Figure 6, there is shown a preferred embodiment of first or internal member 2 which may be employed in any of the embodiments shown in Figures 1 to 5.

The first member 2 has a total of six circumferentially spaced apertures 14I-14VI (the positions of holes 14v and 14VI are shown in dotted outline). The holes are arranged in three diametrically opposed pairs, i. e. 14I and 14VI ; 14II and 14V ; 14ici and 14VI. The holes may be easily formed by drilling diametrically through the tubular member 2 from one side to the other thereby to form a pair of diametrically opposed holes.