GB2512385A - Tank connector, filter and manifold assembly and method - Google Patents

Abstract

A filter and manifold assembly 3, for a fluid supply system comprises: a manifold body defining a manifold volume having a fluid inlet and a fluid outlet to enable fluid flow through the manifold volume. A filter 10, is configured to be receivable within the manifold volume and when so received the filter separates and defines an inlet volume in direct fluid communication with the inlet and an outlet volume in direct fluid communication with the outlet so that fluid flow from the inlet to the outlet must pass through the filter. A removable closure 9, is removably attachable over an access aperture in the manifold body and configured so as to close the access aperture when so attached and allow access to the manifold volume when so removed. The removable closure includes an elongate projecting portion projecting externally of the assembly when the closure is attached, and shaped to be insertable within the manifold volume when the closure is removed. Advantageously the filter and manifold assembly may form part of a gravity-fed header tank irrigation system and the removable closure may provide for in-situ cleaning of the filter.

Description

TANK CONNECTOR, FILTER AND MANIFOLD ASSEMBLY AND METHOD

Field of Invention

The invention relates to a tank connector, filter and manifold assembly' and a method of use, which offers advantages over existing equipment configurations -especially in the manner of its in-situ cleaning. The invention is intended to assist in maintaining a reliable flow of irrigation fluid, outwards from a water filled tank source -containing within it a variety of unwanted matter -to one or more distribution hoses in a gravity fed micro-irrigation system for watering plants.

Where the current discrete items of; a tank connector, valve, inline filter, elbow and one or more Tee fittings (referred to in this text as a tank head assembly') and normally inter-connected by short lengths of hose, may now be integrated together and in a preferred alignment, to form a more useful and more serviceable assembly.

The invention relates to a device and method for improving the operation of a growing environment both when it is operated normally and during periodic cleaning of the filtering means, when source fluids of less than optimum cleanliness need to be filtered and delivered to plants via one or a number of hoses from a low energy source equal to or less than, three metres of irrigation head pressure. The invention and the prior art, are largely discussed in this preferred context, but the more general applicability of the invention will be understood.

Background

Typically a small-scale gravity fed, header tank irrigation system in the region of 200 to 5,000 litres capacity has a tank head assembly' at its fluid outlet port comprising; a tank connector an inline main valve and an inline Y' type filter having a single outlet to which may be connected, a main distribution hose. Beyond this assemblage there is normally connected, via branched connectors, one or a number of sub-main distribution hoses to which are attached lengths of one or more of the following; inline dripper tubing, inline dripper tape, plain lateral tubing fitted with drip emitters, soaker hoses. In the majority of cases the header tanks are refilled manually by a variety of means and with water from whatever source is available.

An action which invariably introduces unwanted matter into the tank and which each time, churns up the contents including accumulating sediments, organic matter, floating matter, etc. All of which can quickly clog up any inline mesh filter connected to the tank outflow. Apart from the difficulty caused by the tank refilling/churning process, in many cases gravity fed irrigation tanks are filled only once a day and once filled they are left to irrigate a crop until they are drained out - perhaps in only a few hours. Towards the end of their daily irrigation cycle semi-buoyant and floating matter will flow through the tank connector into the inline filter giving rise to further clogging.

To reduce the amount of filter clogging, especially caused by the churning issue at the time of refilling, a procedure has been found which works quite well: [1] turn off the main valve from the tank, which is normally situated between the tank outflow connector and the inlet port to the inline Y' type filter: [2] refill the tank (usually from the open top with buckets) and then, when the contents have had time to settle for approximately 30 minutes, [3] remove the filter element for cleaning and refit it, and [4] open the valve again to resume watering.

A drawback to this procedure is that it works for a while on the basis that most of the sinkable material is retained in the tank until such time as the accumulating deposits become too great and overwhelm the filter, at which time the irrigation has to be suspended until the tank is completely cleaned out.

Further, it is very easy to make a mistake about the order and timing of doing things, especially if an operator is working simultaneously with a number of installations on remote communal growing plots.

Examples of current equipment configurations including details of the essential inline Y' type filters can be seen on the following web sites: http://www.jains.com and http://www.azud.com These both offer for sale Gravity Drip Kits' for small scale irrigation systems, for use by families and village communities growing food for themselves across Africa and Asia. More information regarding "1' type mesh filter elements for small scale agricultural applications is available on http://www.amaid.com Irrigation -Manual Filters' the Amaid TAGLINE Filter Series covering Filter Screen Elements. And also from: http://www.naandanjain.com NaanDanJain Plastic Filters -Screen Plastic Filters.

Typically the inline Y' filter housings supplied with these systems contain a tubular woven wire mesh filter element of approximately 155 mesh size (pore size in the region of 100 micron or 0.004" or on the scale of a human hair). The element is totally enclosed within a two part housing the lower half of which can be unscrewed and opened up to remove the tubular filter element for cleaning. The inline filter is needed primarily to protect the emitters (the individual water outflows) which typically have discharge orifices in the region of 1.5 mm to 2.5 mm bore -and which are very easily blocked. A typical small scale gravity fed micro-irrigation system might be less than 1 hectare (10,000 square m, 2.471 acres) in area, and more typically less than 1,000 square metres (approximately 105 ft x 105 ft).

In remote locations even when adhering to the strict operating procedure for tank refilling, conventional mesh filters tend to block up on a daily basis due to the amount of unwanted matter that is introduced each time a tank is refilled from a well, etc. The current procedure for cleaning a tubular mesh filter element is as follows: Turn off the main valve between the tank connector and the inline Y' type mesh filter assembly. Unscrew the lower filter bowl from the filter housing body and pull out the tubular mesh filter element. Wash the filter element in a bucket of water and reinsert it into the filter housing body. Screw on the lower filter bowl to complete the reassembly. Then open the main tank valve to resume watering.

It is worth noting that to reliably clean the inside of the filter housing the whole filter assembly has to be removed from the system and dismantled because it is generally installed upside down and at an angle and cannot be reliably cleaned when installed in a field' environment -by nature devoid of any of the familiar workshop facilities. Cleaning a Y' type filter housing and element is a very simple procedure if carried out in a workshop environment with good lighting and with plenty of clean water on tap. Regrettably the irrigation industry continues to offer its customers a class of filter designed for industrial use and servicing, and has yet to offer a fit for purpose inline filter to its smaller customers in the agricultural sector.

As is evidenced in the current commercial systems cited above, the Y' type filter assemblies are mounted so that the filter element is installed in an angled alignment pointing generally downwards. As a consequence the removal and reinsertion of the tubular filter element is a blind operation, carried out from an awkward angle underneath, resulting in: (A) cross-conta mination, every time a newly cleaned filter element is reinserted upwards -and blindly -into an opened up Y' type filter housing. Where its clean top rim, pushes up through the debris oozing or dribbling from the angled input port inside the upper filter housing, pushing some of the debris into the outflow region inside the filter housing. Once the main valve is turned back on, the cross-over debris is swirled around inside the filter bowl in the outflow chamber and then swept out into the system of hoses. Since, on these small systems being considered, the filter is usually cleaned on a daily basis the unwanted cross-over debris accumulates in the hose system eventually blocking the emitters; (B) and perhaps more importantly the current'?' type filter designs do not allow the main tank valve to be opened whilst the filter housing is opened so as to use the tank water to efficiently flush out the filter element (whilst it is in situ inside the top part of the filter housing) and also in the process to flush out the inside of the filter housing itself.

Given these two significant drawbacks to the current technology a tank-head assembly' having an integral tubular mesh filter element in a new and preferred alignment, and designed to be flushed out without its prior removal, is revealed.

Summary of the Invention

According to the Invention in a first aspect there is provided in the broadest concept of the invention a filter and manifold assembly to form part of a head assembly in a fluid supply system, and for example a tank head assembly in a header tank supplied system, such as a gravity-fed header tank irrigation system.

The filter and manifold assembly comprises: a manifold body defining a manifold volume having a fluid inlet and a fluid outlet to enable fluid flow through the manifold volume; a filter configured to be receivable within the manifold volume such that when so received the filter separates and defines an inlet volume in direct fluid communication with the inlet and an outlet volume in direct fluid communication with the outlet so that fluid flow from the inlet to the outlet must pass through the filter; a removable closure removably attachable over an access aperture in the manifold body and configured so as to close the access aperture when so attached and allow access to the manifold volume when so removed; and is characterised in that the removable closure includes an elongate projecting portion projecting externally of the assembly when the closure is attached, but so shaped as to be insertable within the manifold volume when the closure is removed.

At its most basic level, the filter and manifold assembly therefore comprises three principal components, being a manifold body with a removable closure that together define a manifold volume with the closure in position over its corresponding aperture in the body, and a filter receivable within the manifold volume in such manner that when assembled fluid from an inlet to an outlet has to pass through a flow path that takes it through the filter. The filter is for example a mesh filter as will be familiar.

The invention is distinctly characterised in that the closure includes an elongate projecting portion that is adapted to be inserted through the access aperture and into the filter volume contained within the manifold volume when the closure is unattached from the body. This elongate projecting portion is in particular intended to facilitate cleaning of the filter volume and the manifold volume, for example in that it is adapted to be repeatedly inserted to effect this via a to and fro motion, which is for example assisted by the downward passage of water from the tank or fluid source.

The provision of a removable manifold closure provided with such an elongate projection that is adapted to serve as a cleaning tool confers a number of adva ntages.

In particular, a filter and manifold assembly configured in accordance with the invention is adapted for ready cleaning of the assembly in situ, and in particular cleaning of the filter, without necessitating removal of the filter, and without requiring external tools. Of course, it should be understood that the invention does not preclude such removal for external cleaning, and indeed in the preferred case it is likely that the filter will be removably retained within the volume defined by the manifold body, and will be accessed for removal should the need arise by removal of the manifold closure. However, at least routine cleaning may be effected in situ using the tool constituted by the elongate projection of the closure that is made available for this purpose when the closure is unattached. The manifold closure is thus at least dual purpose in this regard, adapted to serve as a closure over the access aperture in the manifold body when attached and to serve as a cleaning tool insertable into the filter volume within the manifold volume via the access aperture in the manifold body when unattached.

Additionally, the closure may conveniently in a preferred case be provided with a further purpose. In a typical configuration, a manifold closure may be adapted to close a lower end portion of a manifold body, and thus to sit at or towards the bottom of a manifold body when assembled in use. In such a preferred configuration, the closure conveniently defines a manifold sump volume. In particular the sump volume is conveniently defined by the elongate projection, in that the elongate projection comprises a hollow projecting portion defining a sump volume extending downwardly from but in fluid communication with a primary manifold volume defined by the manifold body when the closure is assembled to the body. In this way, the internal volume defined by the elongate projection may serve as a sump volume when the manifold is assembled, with the outer surface of the projection serving as the cleaning tool when the manifold is disassembled.

With the manifold assembled (that is, with the body and closure in the attached configuration) the sump volume is fluidly continuous with the manifold volume defined by the manifold body. In the preferred case, with the manifold assembled, the manifold and filter are so configured that the sump volume is fluidly continuous with the inlet volume defined by the filter. In this way, the sump volume is located and configured to receive debris trapped by the filter and removed from the fluid flow in simple and convenient manner. The elongate projection thus serves a dual purpose of defining a sump volume when the manifold is assembled and of providing a cleaning tool when it is disassembled.

A further particular advantage of the filter and manifold assembly of the present invention is that it lends itself especially conveniently to a vertical configuration in which an inlet is provided towards an upper portion of the manifold body, and for example towards the top, and for example is structured to define an inlet flow that is oriented substantially vertically in use, the sunip extends from a bottom portion of the manifold volume, and for example generally vertically downwards in use, and one or more outlets are provided to a side of the manifold body. Such an arrangement can be contrasted with typical in-line "f" type filters and can confer two notable technical advantages. First, the provision of a vertical inlet feed maximises the effect of any fluid head from the header tank. Second, the provision of a vertical inlet allows for the provision of plural outlets, for example arrayed around the side of the manifold body, in a manner which facilitates consistent flow to each such outlet.

Thus, in the preferred embodiment the manifold and filter assembly of the invention is adapted to sit generally vertically in use such that an inlet is fed from the top of the manifold volume, a closure is provided at the bottom of the manifold volume, and at least one and preferably a plurality of outlets are provided around the side of the manifold body, for example generally evenly spaced therearound.

In accordance with the invention a filter which is preferably a mesh filter when seated in situ separates the manifold volume into an inlet volume in direct fluid communication with the inlet with an outlet volume in direct fluid communication with the outlet(s). In accordance with the preferred vertical in-line arrangement, the manifold body is elongate in a vertical direction with an inlet at the top and outlet(s) at the side as above described, and a filter is shaped and adapted to be received in the volume defined by such an elongate manifold body, and in particular to extend in a longitudinal direction throughout the length of the body, to define and separate therein an inner volume in fluid communication with the inlet and an outer volume in fluid communication with the outlet(s). In particular, the filter comprises an elongate structure having a continuous closed wall and seated in use to be elongate in a longitudinal direction (lying generally vertically in use in the preferred case) so as to define an inner volume along a longitudinal direction and an outer volume annular thereto.

In a preferred case the manifold body comprises at least in major part an elongate housing which in cross-section defines a closed perimeter that is for example a closed polygon such as a regular polygon, or a closed curve such as a circle or an elipse. The housing, or at least a major part of the body thereof, is thus an elongate generally cylindrical or prismatic housing, for example in the preferred case designed to sit vertically in use. In the preferred case a filter such as a mesh filter is provided having a perimeter shape adapted to sit within the volume defined by the perimeter of the housing. In a particularly preferred case the shape of the perimeter of the filter is similar to that of the housing, but with a reduced cross-sectional extent, so that the filter sits within the housing to define an inner central volume in fluid communication with the inlet and an outer annular volume in fluid communication with the outlet(s).

The filter is preferably sealingly received within the manifold volume to effect a fluid seal with an inner wall defining the manifold volume and thus fluidly isolate an inlet volume and an outlet volume within the manifold volume. In the preferred case where a filter is an elongate filter such as an elongate mesh filter this may be effected for example in that each end of the elongate filter is provided with sealing surfaces to be received in and effect sealing engagement with portions of an inner wall defining the manifold volume, and for example portions of an upper and lower wall respectively of the manifold body or of the manifold cover as the case may be.

Sealing means such as 0 rings may be provided.

The manifold cover is removable from the manifold body, for example in that it is provided with a releasable sealing connection, which conveniently comprises mutually engageable threaded portions. This facilitates simple removal for cleaning! emptying of the sump.

In the preferred case, the filter is a mesh filter and for example a tubular woven mesh filter. A typical mesh pore size might be 80 to 300 microns. This is dependent on the degree of particulate filtering that is required.

In accordance with the invention, a manifold body comprises at least one and preferably a plurality of outlets, for example arrayed around the side of the body.

In a preferred case the manifold body comprises at least one and preferably a plurality of outlet arms, each outlet arm defining a flow channel for flow of fluid from one or a number of outlets in the side of the manifold body. It is a particular advantage in the invention that plural symmetrically arrayed outlet arms can be provided around the side of the body, for example in conjunction with a single inlet at the top of the body.

Each outlet arm is preferably adapted for connection to a distribution hose or the like, for example as part of an irrigation system. An outlet arm may be provided with an end connector to facilitate this. An outlet arm may extend generally horizontally from a side wall of the manifold body. An outlet arm may be provided with a connector for connection to a distribution hose or the like, which connectors may include horizontally extending connectors, or elbow connectors extending at an angle to the horizontal, and for example downwardly vertical. Connectors may be integral with the outlet arms, or may be adapted for removal and interchange, for example by threaded engagement. A distal end of a connector is adapted for fluid engagement with a distribution hose, and for example adapted to be inserted sealingly into a hose in familiar manner.

In accordance with the invention in a more complete embodiment, a manifold and filter assembly as above described is provided in combination with an inlet assembly, for example including a connector to connect to an inlet supply source such as an aperture in the sidewall of a tank or an inlet hose for receiving fluid from a fluid source, and a closable valve means, such as a rotational valve, to selectively open and close flow from the supply source in use.

In such a preferred embodiment, and in particular with reference to the preferred vertical configuration, the manifold and filter assembly as above described thus comprises a lower sub-assembly, and the inlet and valve assembly thus comprises an upper sub-assembly, which together constitute a tank head assembly suitable for use for example in a header tank fed fluid supply system in familiar manner.

In a convenient embodiment, the inlet and valve assembly conveniently comprises a hollow housing adapted to connect with or receive a supply hose from a header tank at a first end and adapted to connect with the inlet of the manifold assembly at a second end, with a through bore extending from the first end to the second end, and a valve volume in which is seated a rotatable plug valve having a similar through bore, and being rotatable between a first position in which the respective through bores are aligned to allow flow from a source to the inlet of the manifold volume in use, and a second position where the through bores are not aligned and the flow path is occluded. Such an arrangement will be familiar.

In this more complete embodiment of the invention, there is therefore provided a tank head assembly for a header tank such as a gravity-fed header tank irrigation system as above described.

In a yet more complete embodiment of the invention there is provided a header tank irrigation system comprising a tank head assembly as above described in fluid communication downstream of a header tank, and optionally further in onward fluid communication with a plurality of distribution hoses constituting an irrigation distribution system.

A suitable header tank might be for example one with a capacity in the region of to 5000 litres. A suitable fluid might for example be irrigation water.

The invention is distinctly characterised by the provision of a novel tank head assembly, and in particular with a novel manifold and filter assembly, as above described. Subject to that, other features both upstream and downstream of the tank head assembly, for example relating to header tank or other supply and irrigation distribution, may be as will be familiar from the prior art.

Brief Description of the Figures

The invention will now be described by way of example only, with reference to figures ito 14 of the accompanying drawings, which are drawn to scale, in which: Figure 1 is a general perspective view of a tank head assembly' showing an upper major sub-assembly and a lower major sub-assembly, connected in a normal operational state and preferred orientation, in accordance with the present invention; Figure 2 is an exploded view of the assembly shown in figure 1 and revealing two distinct sub-assemblies; Figure 3 is a sectional perspective view of the upper major sub-assembly comprising a combined tank connector and plug valve; Figure 4 is a rotated perspective view of a plug valve core as revealed in figure 3 exposing the fluid passageways; Figure 5 is a front perspective view of a combined tank connector and plug valve housing, capable of accommodating a mating plug valve core shown in figure 4; Figure 6 is an underside view of figure 5 showing the related fluid passageways; Figure 7 is a sectional perspective view of the lower major sub-assembly comprising a filter housing, tubular filter element, manifold, hose connectors and a multi-purpose sump of the same invention; Figure 8 is an enlarged cross-sectional view of a multi-purpose sump feature revealed in figure 7; Figure 9 is a front sectional view, showing in more detail the assembled relationships between the filter housing, multi-purpose sump and tubular filter element; Figure 10 is a front perspective view of a tubular filter element; Figure 11 is a bottommost perspective view of a tubular filter element showing engaging keyways or slots, with filter mesh omitted for clarity; Figure 12 is a similar view to figure 7 but with a multi-purpose sump component unscrewed and inverted in preparation for in-situ filter cleaning; Figure 13 is a similar view to figure 12 but with an inverted multi-purpose sump component raised to an uppermost position inside an installed tubular filter element; Figure 14 is a perspective view of a thin section radially-bristled brush designed, when required, to be attached to the outside bottom end of the multi-purpose sump component to augment the cleaning action of the flushing water in combination with the up and down movement of the multi-purpose sump component.

Like numerals are used where applicable.

Detailed Description of the Figures

Referring to figures 1 and 2 the tank head assembly' (1) comprises two major sub-assemblies, the first being an upper combined tank connector and 900 rotary plug valve (2). And the second being a lower combined filter, manifold and sump (3) having four outlets for connection to irrigation hoses (not shown). The two major sub-assemblies are connected together (4) to provide a watertight path for irrigation fluid to flow without reduction in the fluid path cross-sectional area from a tank connector, through a valve, mesh filter and manifold, to four hose connections.

Figures 3, 4, 5 and 6 show in sectional and perspective views more of the detail in the upper major sub-assembly (2), whilst figures 7, 8, 9, 10, 11, 12 and 13 show in sectional and perspective view, more of the detail in the lower major sub-assembly (3) in a number of operative positions. And figure 14 shows a thin section radially-bristled brush attachment used as a more thorough cleaning aid.

In more detail the upper major sub-assembly (2) (referring here to figures 3, 4, 5 and 6) comprises a hollow tank connector housing (5) having a flange (11) and an externally threaded (1" BSP) portion on its furthest away and open horizontal end (ha), for the purpose of making a connection through an aperture (33.5 mm diameter) in a tank wall (not shown) upon which end a thick resilient washer (13) and a rigid shim washer (14) are threaded, to be retained by a hand tightened plain nut (15) (1" BSP), to effect a watertight seal in the tank wall.

The housing, having a through-bore internally stepped barrel, with integral internal stubby alignment collar (llb), is open at the front horizontal end (17) to receive an open ended hollow plug valve core (6) having three side apertures in its long cylindrical or plug portion (18) which terminates in a thin walled plain end (lic).

When assembled, the two parts are made watertight by the inclusion of an 0 ring (19a) seated in a groove (19) on the outside of the plug valve cylindrical core which provides a forward positioned seal close to the outermost front face of the hollow tank connector housing. Also the plain end (lic) registers as a sliding fit on the outside of the alignment collar (hib) and this inhibits the migration of gritty particles into the rotatable main bearing surfaces (lid) and (lie).

The open ended hollow plug valve core has at its other, closed outermost front end, a skewed long leg turn knob (20) for gripping and turning, inboard and adjacent to which is attached a short stubby lug (21) which projects into a radial track (22) just longer than a quadrant, in the front of the hollow tank connector housing, limiting the assembled valve plug rotation to 900 in a clockwise direction, from a fully open position (vertically aligned) to a fully closed position (horizontally aligned).

The assembly of the plug valve core into the hollow tank connector housing is effected by aligning the two parts so that the two opposing pawls (23) extending from the outside diameter of the plug valve core, immediately behind the long leg turn knob, are readily sprung over two reduced diameter opposing rim portions (24) in the front face of the hollow tank connector housing (these are at an angle of 45° clockwise from the vertical). After which the hollow plug valve core is rotated clockwise a further 45° to pre-set the valve to the closed position ready for use. In this state the skewed long leg (25) of the turn knob is horizontal and pointing to the left when viewed from the front and the hollow tank connector is orientated so that the flat planar base (26) with the large circular aperture (27) and overhanging side keyway slots (28) is facing vertically downwards.

For the purposes of calculation in the chosen example, the tank connector thread is 1" BSP having a plain hollow bore of 24 mm (24 millimetres) to provide a fluid flow cross-sectional area of 4.5 cm2 ( 4.5 square centimetres) exiting the tank. To keep the hollow plug valve core diameter relatively small the aperture (29) for the fluid to exit from it in a downward direction is not circular but narrowed and elongated, to a round ended aperture' comprising two opposing half circles separated by a 16 mm square, totalling 32 mm long x 16 mm wide which maintains a consistent aperture of 4.5 cm2 through the thin wall of the cylindrical plug core.

The aperture (30) exiting from the underside of the tank connector housing is initially the same shape as the matching elongate round ended plug core aperture (29). However the flow path expands quickly over the short distance to the base of the hollow tank housing, doubling the area of the flow path cross-section to 9 cm2 whilst at the same time changing from an elongate aperture (30) to a circular aperture (27) of 34 mm bore.

This is in readiness for the fluid passageway to continue downwards in this generous dimension into the lower sub-assembly (when fully assembled) and ultimately into the core of the tubular mesh filter element. By this approach, when comparing like for like fluid flow capacity, a plug valve can be made significantly smaller than is currently manufactured.

Extending from the topmost surface of the hollow tank connector housing there is an 8 mm through-bore ring barbed spigot (32), onto which may be pushed a resilient clear-walled sight tube (not shown) extending upwards to be secured, and to act as a fluid level indicator external to a tank (not shown) to indicate the fluid level within the tank.

Diametrically opposite the elongate round ended aperture' portion of the open ended hollow plug valve core, there is a circular aperture (33) approximately 12 mm bore and a further identical aperture (34) 9Q0 around the circumference in an anti-clockwise direction on the same perpendicular planar axis. The purpose of the two smaller and circular apertures is to provide conduits for the tank fluid to communicate with the sight tube, when the plug valve core is set vertically in an open state and also when it is rotated 900 clockwise to a closed state. There being no requirement for an intermediate position.

The underside of the tank connector housing (26) is planar and square (in underside view) in the centre of which there is a fluid passageway aperture (27) of 34 mm bore. The housing extends downwards a short distance on either side of the square planar base surface, into which extensions are set, two opposing keyway slots (28).

The keyway slots, inclined gently upwards from front to back, are designed to mate with slide fit matching inclined keys, projecting from the sides of the uppermost planer portion of the major lower sub-assembly.

The major lower sub-assembly (3), generally referring here to figures 1 and 2 comprises a hollow, vertically aligned, cylindrical filter housing (7) having a tubular manifold arm extending from either side, high up on the filter housing, to provide for, four independent hose connections (8). A multi-purpose sump (9) is screwed onto the base of the filter housing, which sump bears a passing resemblance to an ice cream cone with a cylindrical stem. Figures 7, 8, 9, 10, 11, 12 and 13 are specific to these features.

In more detail the topmost region of the hollow cylindrical filter housing is formed into a square planar surface or platform (40), having a large circular aperture (41) in its centre (34 mm bore) around which is an 0 ring groove (42), to later contain an 0 ring (43). To either side of the platform there is a side mounted key or rib (44) projecting outwards and gently inclined from front to back. Below the platform region the filter housing cross-section changes to a circular one having a general outside diameter of 60 mm and a bore of 56 mm (45) save for its uppermost region, within which there is a short length of a concentric internal thread (46) of 1 1/4" BSP), to later accommodate a threaded top portion of a new design of tubular mesh filter (10). The bottom portion of the filter housing has a short length of a concentric external thread (47) of 63 mm outside diameter, above which there is a concentric groove (48) to accommodate an externally fitted 0 ring (49), which abuts on its uppermost surface against a concentric raised lip (50) integral with and extending around the outside diameter of the filter housing.

Further, the lowermost rim of the main body of the filter housing (7) having a 56 mm plain bore, is designed to press against the resilient outboard sloped surface of the inverted V' shaped seal (67) on the multi-purpose sump (9), creating a radial liquid seal from the resulting interference fit, when this sump is screwed onto the assembly of the filter housing and the tubular filter element', for example in readiness for normal irrigation use.

The main body of the filter housing (7) has integral hollow manifold arms (51) extending out from each side of its upper half, with top (52) and bottom (53) webbed reinforcements. Each manifold arm has one endwise (54) and one sideways (55) branch terminating in an externally threaded socket end (1" BSP) (56) & (57). To facilitate connection with up to four hose connectors (8). The Straight (58) and Elbow (59) shaped ring barbed hose connectors shown have large central flanges (29 mm diameter), which are used to retain the connectors inside four front-constricted (24 mm bore) tightening nuts (60) of 1" BSP thread, along with resilient washers (61) which are employed to achieve watertight joints.

The front-constricted nut is threaded from one open end and has a thin section reduced bore diameter at the other end (16). The reduced bore diameter (24 mm) serves to retain a centre-flanged hose connector having a flange outer diameter of 29 mm.

The four ring barbed fluid outlets are 12 mm bore, which together provide for a cross-sectional area of 4.5 cm2 which is consistent with the upstream minimum cross-sections employed in the hollow tank connector housing, the plug valve open end and elongate side aperture, and the tank connector bore into the tank. The four ring barbed connectors are provided so that four resilient hoses (not shown) can be pushed onto the connectors to connect a supply tank to a system of irrigation hoses and emitters (not shown). For a lesser number of hose outlets, blanking disks (not shown) or threaded end caps (not shown) could be used to close off the surplus threaded sockets.

The lower portion of figure 7 shows a multi-purpose sump (9) attached to the bottom of the filter housing (7). The sump is shown in cross-section, in isolation and in more detail, in figure 8. The sump is a thin walled hollow body of generally cylindrical section (62) -approximately 30 mm outside diameter along its long parallel stem length -in the vertical axis which projects downwards and which is closed-off at its bottom end (63). There is provision at the closed end, in the form of a raised ring (64) about the central axis, for future attachment of a thin section radial-bristled brush (82) shown in Figure 14 or a thin section disc shaped scraper (not shown). At the other (top) end of the thin walled cylindrical sump portion the diameter expands in the form of an inverted thin-walled truncated cone shape (65), above which the diameter increases in a horizontal direction to form a narrow annular ring (66) which then increases in diameterfurther, whilst taking on the form of an inverted V' shaped annular seal (67). Beyond which the diameter increases further in a horizontal direction to form a larger annular ring (68) before turning abruptly upwards to form a threaded outer annular rim or cap (69), having a 63 mm internal thread and a series of external ribs (70) spaced around the ultimate periphery (71) for gripping by hand during assembly and disassembly.

Concentrating briefly on the importance of the V7 shaped annular seal in the multi-purpose sump, the geometry, dimensions and material properties come into play when it is screwed onto the bottom of the filter housing, containing within it a tubular filter element. This because of the desired resilient interference relationships created: (A) between the inside bottom rim of the filter housing and the outboard side of the inverted V' shaped seal in the multi-purpose sump; AND (B) the inboard side of the said V' seal and the outer bottom rim of the tubular filter element and this relationship is more clearly illustrated in figure 9. Figure 9 is a front sectioned view of the three assembled components -the view has been truncated both above and below the area of interest for clarity.

More generally the multi-purpose sump the 63 mm internal thread stops short of the top of the annular rim or cap (69) to provide part of a nesting-housing (72) for an 0 ring (49) upon assembly -which nesting provides for a watertight seal between the bottom region of the filter housing and the top region of the sump across the horizontal section of the 0 ring, i.e., between the inner wall of the cap and the bottom of the 0 ring groove in the filter housing. By this approach the seal is not affected by how tight the multi-purpose sump is screwed onto the base of the filter housing. And unlike the current filter assembly designs the proposed 0 ring and mating surfaces are raised up from their common bottommost position, keeping them away from tumbled and dribbled debris. Further the sealing surfaces are exposed and very easily cleaned prior to assembly.

The multi-purpose sump has four downward facing, squared stubby key projections (73) equi-spaced around the invert truncated cone portion (64). These may be used later (when the sump is inverted) as a tightening and un-tightening aid during assembly and cleaning of the tubular filter element. The multi-purpose sump also has an extended circular collar (74) projecting vertically downwards inboard of the ultimate outer cap diameter. The collar (74) acts as a splash guard during the in situ tubular filter element cleaning process, i.e., when the sump is employed in an inverted state.

Referring again, generally to figure 7 and more specifically to figures 9, 10 and 11, the filter housing (7) contains an installed generally-cylindrical tubular filter element (10) having a short externally threaded top portion (75) (1 1/4" BSP) and a long vertical tubular filter mesh portion (76) with over-moulded reinforcement bars (77) and rims, and a bottom rim portion (78) of 44 millimetres plain outside diameter, having inside its periphery four short and vertical stubby equi-spaced keyways (79) which are opened to the hollow core on their inboard faces (illustrated more clearly in figure 11 and where the mesh screen (76) has been omitted for clarity). The nominal bore of the in-moulded tubular filter element mesh screen throughout its extent is 32 mm.

When the tubular filter element (10) is screwed fully into the mating thread inside the filter housing (7), when viewed from the bottom, there is an uninterrupted 6 mm radial clearance between the inside plain 56 mm bore of the filter housing and the plain 44 mm outside diameter of the tubular filter element. So that, when the multipurpose sump (9) is unscrewed from the assembly the 6 mm annular clearance, facing downwards, is exposed to the atmosphere and allows for effective flushing out of the assembly during in-situ cleaning.

Further, the plain lowermost rim of the tubular filter element having a 44 mm outside diameter, is designed to press against the resilient inboard sloped surface of the inverted V shaped seal (67) on the multi-purpose sump (9), creating a radial liquid seal from the resulting interference fit, when this sump is screwed onto the assembly of the filter housing and the tubular filter element', for example in readiness for normal irrigation use.

Currently a popular mesh size for the tubular woven mesh filter portion (76) is 155 mesh (100 micron pore size). Other mesh sizes may also be used typically ranging from 50 to 200 mesh size, equivalent to 300 to 80 micron. This is dependent on the degree of particulate filtering that is required to minimise the most common form of gravity-fed irrigation system blocking -which is Emitter' blocking.

The two major sub-assemblies are joined together by aligning the side keys (44) in sub-assembly (3) with the side keyway slots (28) in sub-assembly (2) and pushing the sliding arrangement from front to back until the back stop (80) prevents any further movement of sub-assembly (3). The reason for the gently inclined sliding assembly is to reduce the dragging effect across the uppermost surface of the 0 ring (43) and thereby ensure a more durable seal for repeated use, by untrained operators in the field in uncontrolled and often extreme conditions.

In normal use the Tank Head Assembly' will only experience a maximum of a couple of metres of head pressure (c 0.2 bar gauge or 3 psi) -and this only when a tank is full. Therefore the components could be largely manufactured as thin walled polypropylene injection mouldings of the order of 1.5 mm wall thickness.

The three 0 rings could be made from EPDM, similarly the four resilient washers (for the hose connections) and the thick resilient tank connector washer could also be made from EPDM. It is recommended that a durable rust resistant material such as stainless steel is used to make the tubular woven mesh filter, although a punched or chemi-etched foil could be used as an alternative in an in-moulding process to mould the filter element as a single component. Nylon woven mesh could be used but it is not as durable as stainless steel.

Figure 14 shows a thin section radially-bristled brush (82) having a central plastic injection moulded region with an aperture (83) and in-moulded stubby bristles (84) arranged around its periphery, for example made from nylon, and having an outside bristle diameter equal to or marginally less than the central bore of the tubular filter element. The radially-bristled brush can be fastened to the bottom outside end of the multi-purpose sump (9) (refer to figure 9) by a self-tapping screw (not shown) passing through the aperture and the base of the sump, and positioned centrally by the raised ring (64) on the sump end. The use of this attachment to the sump, when used in the manner described for the normal cleaning of the interior of the tubular filter element (10), would be helpful if the shearing action of the water flow and the up and down movement of the inverted sump rubbing intermittently against the filter mesh, had insufficient cleaning action to scour out an accumulation of deposits. By this method, even when the tubular filter element is heavily soiled with stubborn deposits it is not necessary to remove the tubular filter element (10) from its housing.

ASSEMBLY OFTHETANK HEAD ASSEMBLY

There is no right order in which to assemble the components however the following is recommended, with reference especially to figures land 2: 1. Pick up a hollow plug valve core (6) and assemble the 0 ring (19a) onto the cylindrical plug core.

2. Pick up the hollow tank connector (5) and align the plug valve core, off-set by 45° clockwise, i.e., with the skewed long leg on the front of the knob pointing downwards and to the left, and then push the plug valve core fully into the housing so that the two pawls latch over the locally reduced rim diameter, and turn the knob a further 45° clockwise to set the valve assembly in the closed position.

3. Put the sub-assembly down and pick up the filter housing (7) and then the tubular filter element (10) and by hand, push the threaded top of the tubular filter element into the open bottom of the filter housing and inwards until it engages with the internal thread. Using fingers gently screw in the tubular filter element until it stops rotating.

4. Install the largest of the 0 rings in its groove on the outside of the lower portion of the filter housing.

5. Pick up the multi-purpose sump (9) and screw it onto the bottom threaded portion of the filter housing until it is hand tight.

6. Take four front-constricted nuts (60) and insert the centre flanged hose connectors (2 x straight (58) and 2 x elbow (59)) into the nuts, push on a resilient washer (61) onto the inboard end of each connector, pushing the washer down into the threaded end of each nut, and hand screw the four nut assemblies onto the threaded sockets on the manifolds -as shown in figure 1. whilst swivelling the elbow connectors to their approximate position for use.

7. Insert the remaining 0 ring into the circular groove on the flat top of the filter housing.

8. Slide the two major sub-assemblies together until the backstop (80) prevents further movement -at this juncture a more permanent fixing can be made if necessary by screwing the sub-assemblies together using the screw/dowel holes (81).

9. Leave the tank connector thick resilient washer, rigid shim washer and plain nut, loose at this time.

ASSEMBLY ONTO ATANKAND TURN ON WATER

Prepare a tank (not shown) for use by standing it on a supporting platform one to two metres above the ground to be irrigated, and drill a 34mm diameter hole in the side wall approximately 50 mm above the bottom (measured from inside the tank). Then:

1. With a fully assembled tank head assembly' and the multi-purpose sump hanging bottommost, outside of the tank, slide the thick resilient washer fully on to the threaded tank connector end and push the threaded end of the tank connector housing through the 34 mm diameter hole in the side wall of the tank. Then from inside the tank slide the shim washer onto the exposed thread, then screw on the plain nut and hand tighten.

2. Push on a length of clear sight level hose onto the vertical ring barbed spigot on the top of the tank connector housing (sufficient to reach to the top of the tank) and secure the top end of the clear hose to the top region of the tank -leaving the hose top end, open to the atmosphere.

3. Push on four resilient distribution hoses onto the ring barbed manifold fittings from a prepared ground laid irrigation system.

4. Fill the tank with water and open the valve to release tank water through the assembly, into the hoses and out through the Emitters on to the ground.

CLEANING THE TUBULAR FILTER ELEMENT AND HOUSING

Referring again to figure 1 it will be seen that externally, in normal operation, the multi-purpose sump is screwed hand tight onto the bottom of the filter housing.

Figure 9 shows that this assembly creates a resilient seal between the bottom outer rim of the tubular filter element and the inboard face of the inverted V' seal, present in the multi-purpose sump. This separates the out-flowing region of the filter housing -outside of the tubular filter element -from the inflowing region which is inside the confines of the tubular filter element.

Figure 9 further shows that the same action of assembly creates a resilient seal also between the outboard face of the inverted V seal present in the multi-purpose sump and the bottom inner rim of the filter housing -because the two mating components are so dimensioned as to create a resilient interference fit.

The purpose of the large 0 ring employed at the topmost portion of the multi-purpose sump threaded cap is to provide a reliable gas tight' seal to the passage of air and or water in either direction. The aforementioned inverted V' type seal in the first instance providing an effective barrier to the passage of sediments, particulates, agglomerated biological matter, etc. The pressure differential across either of the seals at no time exceeding 0.2 bar gauge, equivalent to 3 psi and most often in the region of a 1 metre depth of water in a tank when full, i.e., 0.1 bar gauge or 1.5 psi.

In the case of installing (screwing in) a new or a cleaned tubular filter element into the filter housing, it will be noted that the hand assembly operation (featured earlier in the text) may be omitted if the multi-purpose sump is inverted as in figure 12 and the sump stem is inserted fully into the hollow core of the tubular filter element (figure 13), so that the four external keys now projecting upwards from the sump conical wall engage fully into the four stubby square keyways in the base of the tubular filter element. The two components having clearance fits for this. With the two components interlocked together the sump may be held and turned, to screw the tubular filter element fully into the receiving internal thread inside the top region of the filter housing. Rather like using a socket set. In like manner removal of a tubular filter element is the reverse of this procedure.

The fixed vertical alignment -by mechanical attachment to the tank -of the filter housing, tubular filter element and multi-purpose sump assembly (figure 1), ensures that the tank water and all manner of debris is flushed vertically downwards (by the force of gravity) in a continuous stream of water when the hollow plug valve is opened fully -especially when the tank is full. This phenomenon is useful in normal operation as the denser of the accumulating entrapped solids inside the tubular filter element tend to drop down to the lowest level inside the sump, below the filter mesh -so reducing the frequency of filter cleaning, over the technology currently on offer for small scale systems. Further, during operation the assembly may be tapped gently with a stick to dislodge debris obstructing the inside of the filter mesh, so that it gravitates harmlessly into the multi-purpose sump.

More particularly this arrangement may be exploited to clean a tubular filter element without its removal from the filter housing eliminating the current assembly problem of solids crossing-over, as a cleaned tubular filter element is being re-inserted into the open and angled blind underside of the filter housing.

The procedure for this is illustrated in figures 12 and 13. Where figure 12 shows the sump unscrewed from the filter housing and inverted, in readiness for the sump stem to be inserted fully up through the bottom of the vertically aligned hollow tubular filter element. And figure 13 shows the sump stem inserted up into the hollow tubular filter element, in readiness for the cleaning operation to commence.

In both the figures the hollow plug valve would be closed to the flow of irrigation fluid. Also it will be evident that when the multi-purpose sump is initially unscrewed from the filter housing (with the water turned off) the sump can then be very easily cleaned out for example by shaking, wiping, rinsing, etc. before the commencement of the tubular filter element cleaning.

THE TUBULAR FILTER ELEMENT CLEANING OPERATION

The following is very effective when a full tank of water is available and the contents have been given time to settle -with the outgoing plug valve in a closed state: Holding the inverted multi-purpose sump firmly up into the tubular filter element with one hand, an operator can use his or her other hand, to fully open the hollow plug valve (located 200 mm above) by turning it 900 anticlockwise, to then allow a full bore stream of tank water to drop onto the blind horizontal end of the loose fitting sump stem. The operator now allows the inverted sump to be pushed slowly downwards by the force of the water (about S seconds), which floods out and down the annular gap between the outside diameter of the sump stem and the inside diameter of the tubular filter element. And also through the apertures in the tubular filter mesh, initially in a thin forceful ring, into the filter housing, to then be flushed rapidly out through both the opened bottom of the filter housing and the opened bottom of the tubular filter element. The process is made more effective if the sump stem is jiggled up and down as the water gushes out -for convenience into a bucket placed on the ground immediately below the opened assembly.

The inward facing surface of the tubular filter element mesh is cleaned by the forceful sheering or scouring action of the water, downwards along the mesh surface in a thin ring-like manner as the downward water stream impacts on the inverted blind end of the sump stem, and turns sharply 90° to radiate all around into the facing filter mesh. After which a portion of the radiating stream suddenly turns 900 again, forming a thin-walled tubular formation, to race down the inside of the tubular filter mesh and drain out, carrying sheered-off debris with it. The remainder of the fluid stream is projected through the mesh, cleaning the small apertures in the process, before being flushed out of the bottom of the filter housing-flushing out the inside cylindrical wall of the filter housing in the process.

Very occasionally the tubular filter element might require a more thorough cleaning, i.e., to remove lime scale deposits, etc, in which case it can either be unscrewed from the filter housing using the inverted multi-purpose sump to unscrew it. Or it can be left in situ and cleaned with a radial-bristled brush (82) (illustrated in figure 14) or a resilient scraper disc (not shown) fastened to the blind end of the sump stem, using for example a centrally positioned self-tapping screw (not shown). In which case, before screwing the sump back on to the filter housing the bottom end of the sump would need to be in a watertight condition -for example, if need be the screw and or the radial brush could be left in situ.

In the event that the effectiveness of the resilient inverted V' seal between the filter housing and the tubular filter element appears to be diminishing -after a very prolonged period of use -the sealing effect can be restored by caulking the radial V' channel with a resilient material such as string, twine, etc. or filling the channel with, for example a resilient polyurethane compound. Given the low operational pressures envisaged (under 0.2 bar gauge or 3 psi across the seal), the design of the inverted V' seal lends itself to a number of restorative procedures to maintain its effectiveness.

The design of the filter housing, its left and right manifold arms and the configuration of the out flowing hose connections, provide further trap areas within the filter housing for very fine sediments to accumulate harmlessly. For example in the annular recesses formed by the bottom mounted hose connectors, up through which pass the inward projecting ring barbed spigots. In which case the hose connectors could be unscrewed, cleaned and refitted. Fine sediments will also tend to precipitate out along the inside bottom of the manifold arms rather than be propelled out through the straight end connectors, which again have inward projecting ring barbed spigots. If the four front-constricted nuts and hose fittings (straight and elbow) are removed temporarily, the short filter housing manifold arms are easily cleaned in situ.

Further, entrapped air and any gas generated by reactions occurring inside the manifold arms, is able to trickle out upwards from the manifold arms, through the mesh at the top of the tubular filter element to be released harmlessly to atmosphere though the sight glass tube. Likewise any small quantity of floating matter present inside the manifold arms -for example which has agglomerated or grown since passing through the filter element -will remain buoyant and captive in the uppermost regions inside the manifold arms, when the irrigation fluid is flowing normally. And will tend to remain buoyant atop the fluid to become beached inside the manifold arms as the last of the fluid drains out from the manifold arms through the hose connections.

In the example given the single fluid passage (24 millimetres bore) through a tank connector fitting of 1" BSP external thread size was determined so as to be equal in cross-section to the sum of the cross-sections of the four hose connector outflows.

The benefit of this may be applied in scaled manner upwards for larger tank distribution systems or downwards to a tank head assembly to supply irrigation water from a water butt used in a garden setting.

For example many existing water butt plug valves have a 3/4" BSP external thread for the tank connection (requiring a 25 mm diameter hole in the side of the tank).

Typically these have a nominal 20 mm fluid bore through the tank connection portion which reduces to a nominal 10 mm bore through the plug valve portion -reducing the actual tank outflow to only a quarter (25%) of its potential.

It will be evident that the plug valve aperture features and the scaled geometry of the upper major sub-assembly of the present invention may be applied in similar fashion to the common water butt plug valve used extensively in gardens, etc. with or without the attachment of a filtering and/or manifold means.

The above examples serve to illustrate the design and scope for material and performance variations, the assembly, method of use and servicing in situ of the present invention and it will be understood that, referring here to an assembled Tank Head Assembly', it will be evident to those skilled in the art that further modifications and variations are possible without departing from the underlying principles of the invention, and that all such modifications and variations should be considered within the scope of the present invention.

Claims (33)

1. CLAIMS1. A filter and manifold assembly for a fluid supply system comprising: a manifold body defining a manifold volume having a fluid inlet and a fluid outlet to enable fluid flow through the manifold volume; a filter configured to be receivable within the manifold volume such that when so received the filter separates and defines an inlet volume in direct fluid communication with the inlet and an outlet volume in direct fluid communication with the outlet so that fluid flow from the inlet to the outlet must pass through the filter; a removable closure removably attachable over an access aperture in the manifold body and configured so as to close the access aperture when so attached and allow access to the manifold volume when so removed; characterised in that the removable closure includes an elongate projecting portion projecting externally of the assembly when the closure is attached, but so shaped as to be insertable within the filter volume contained within the manifold volume when the closure is removed.
2. 2. A filter and manifold assembly in accordance with claim 1 wherein the elongate projecting portion is so shaped as to facilitate cleaning of the filter volume and the manifold volume when the closure is removed by repeated insertion through the access aperture assisted by the downward passage of fluid flow from a fluid supply system.
3. 3. A filter and manifold assembly in accordance with claim 1 or claim 2 wherein the elongate projecting portion is hollow to define a sump volume extending from but in fluid communication with a primary manifold volume defined by the manifold body when the closure is assembled to the body.
4. 4. A filter and manifold assembly in accordance with claim 3 wherein the manifold and filter are so configured that the sump volume is fluidly continuous with the inlet volume defined by the filter when assembled in situ.
5. 5. A filter and manifold assembly in accordance with any preceding claim comprising an inlet provided towards an upper portion of the manifold body.
6. 6. A filter and manifold assembly in accordance with claim 5 comprising an inlet provided at the top of a manifold body and structured to define an inlet flow that is oriented substantially vertically in use.
7. 7. A filter and manifold assembly in accordance with claim 5 or 6 wherein the elongate projecting portion is hollow to define a sump volume extending from a bottom portion of the manifold volume.
8. 8. A filter and manifold assembly in accordance with claim 7 wherein the sump volume extends generally vertically downwards in use.
9. 9. A filter and manifold assembly in accordance with any preceding claim comprising one or more outlets to a side of the manifold body.
10. 10. A filter and manifold assembly in accordance with any preceding claim adapted to sit generally vertically in use such that an inlet is fed from the top of the manifold volume, a closure is provided at the bottom of the manifold volume, and at least one outlet is provided in the side of the manifold body.
11. 11. A filter and manifold assembly in accordance with claim 10 having a plurality of outlets provided in the side of the manifold body.
12. 12. A filter and manifold assembly in accordance with claim 11 having a plurality of outlets generally evenly spaced therearound.
13. 13. A filter and manifold assembly in accordance with any preceding claim wherein the manifold body is elongate and a filter is shaped and adapted to be received in the volume defined by such an elongate manifold body to extend in a longitudinal direction throughout the length of the body, to define and separate therein an inner volume in fluid communication with the inlet and an outer volume in fluid communication with the outlet(s).
14. 14. A filter and manifold assembly in accordance with claim 13 wherein the filter comprises an elongate structure having a continuous closed wall and seated in use to be elongate in a longitudinal direction of the manifold body so as to define an inner volume along the longitudinal direction and an outer volume annular thereto.
15. 15. A filter and manifold assembly in accordance with claim 13 or 14 wherein the manifold body comprises an elongate housing which in cross-section defines a closed perimeter and a filter is provided having a perimeter shape adapted to sit within the volume defined by the perimeter of the housing.
16. 16. A filter and manifold assembly in accordance with claim 15 wherein the shape of the perimeter of the filter is similar to that of the housing, but with a reduced cross-sectional extent, so that the filter sits within the housing to define an inner central volume in fluid communication with the inlet and an outer annular volume in fluid communication with the outlet(s).
17. 17. A filter and manifold assembly in accordance with any preceding claim wherein the filter is sealingly received within the manifold volume to effect a fluid seal with an inner wall defining the manifold volume and thus fluidly isolate an inlet volume and an outlet volume within the manifold volume.
18. 18. A filter and manifold assembly in accordance with any preceding claim wherein the manifold cover is removable from the manifold body in that there is provided a releasable sealing connection between them.
19. 19. A filter and manifold assembly in accordance with claim 18 wherein the releasable sealing connection comprises mutually engageable threaded portions.
20. 20. A filter and manifold assembly in accordance with any preceding claim wherein the filter is a mesh filter.
21. 21. A filter and manifold assembly in accordance with claim 20 wherein the filter is a tubular woven mesh filter.
22. 22. A filter and manifold assembly in accordance with claim 20 or 21 wherein the filter mesh pore size is 80 to 300 microns.
23. 23. A filter and manifold assembly in accordance with any preceding claim wherein the manifold body comprises at least one and preferably a plurality of outlet arms, each outlet arm defining a flow channel for flow of fluid from an outlet in the side of the manifold body.
24. 24. A filter and manifold assembly in accordance with claim 23 comprising plural symmetrically arrayed outlet arms around the side of the body.
25. 25. A filter and manifold assembly in accordance with claim 23 or 24 wherein each outlet arm is adapted for connection to a distribution hose.
26. 26. A filter and manifold assembly in accordance with claim 25 wherein each outlet arm is provided with an end connector to facilitate connection to a distribution hose.
27. 27. A filter and manifold assembly in accordance with one of claims 23 to 26 wherein an outlet arm extends generally horizontally from a side wall of the manifold body.
28. 28. A manifold and filter assembly in accordance with any preceding claim in combination with an inlet and valve assembly including a connector to connect to inlet supply source such as an aperture in the sidewall of a tank for receiving fluid from a fluid source, and a closable valve means to selectively open and close flow from the supply source in use.
29. 29. A manifold and filter assembly in accordance with preceding claims 1 to 27 in combination with an inlet and valve assembly including a connector to connect to an inlet supply source such as an inlet hose for receiving fluid from a fluid source, and a closable valve means to selectively open and close flow from the supply source in use.
30. 30. An assembly in accordance with claim 28 wherein the inlet and valve assembly comprises a hollow housing adapted to connect with an aperture in the sidewall of a tank for receiving fluid at a first end and adapted to connect with the inlet of the manifold assembly at a second end, with a through bore extending from the first end to the second end, and a valve volume in which is seated a rotatable plug valve having a similar through bore, and being rotatable between a first position in which the respective through bores are aligned to allow flow from a source to the inlet of the manifold volume in use, and a second position where the through bores are not aligned and the flow path is occluded.
31. 31. An assembly in accordance with claim 29 wherein the inlet and valve assembly comprises a hollow housing adapted to receive a supply hose from a source at a first end and adapted to connect with the inlet of the manifold assembly at a second end, with a through bore extending from the first end to the second end, and a valve volume in which is seated a rotatable plug valve having a similar through bore, and being rotatable between a first position in which the respective through bores are aligned to allow flow from a source to the inlet of the manifold volume in use, and a second position where the through bores are not aligned and the flow path is occluded.
32. 32. A tank head assembly for connection to a fluid source such as a gravity-fed header tank irrigation system comprising an assembly in accordance with any preceding claim.
33. 33. A header tank irrigation system comprising a header tank, a tank head assembly in accordance with claim 32 in fluid communication downstream of the header tank, and further in onward fluid communication with a plurality of distribution hoses, connection fittings and fluid emitters constituting an irrigation distribution system.