GB2259775A - A water metering unit - Google Patents

Abstract

A water metering unit comprises a base member which includes a connecting portion 1 adapted for connection into a water supply pipe and a housing portion 3 capable of housing a water metering means. The connection portion has an inlet 9 and outlet 11 through which water from the supply pipe can be directed into and away from the housing portion. The unit further includes an insert member 17 capable of removable insertion into the housing portion of the base member, the insert member containing water flow metering means 29 for measuring a volume of water passing through the meter means and an inlet and outlet 19, 21. <IMAGE>

Description

WATER METERING UNIT Field of the Invention This invention relates to a water metering unit, of the type suitable for connection into a water supply to measure the volume of water consumed at a particular outlet. The invention also relates to an insert member for insertion into the unit.

Background to the Invention Water metering units are well known, of the type which are connected into a mains water supply at a point where water is consumed from that supply, to monitor the volume consumed.

They are commonly used, for instance, to monitor water consumption by a domestic user at his place of residence, or by a factory or office or similar commercial user. The user can then be charged for his water supply according to the volume which he is known to have consumed over a particular period.

Known water metering units typically comprise a base, which is connected into the mains supply pipe and which has an inlet pipe for receiving water from, and an outlet pipe for discharging water to, the mains pipe. In addition to this base, the unit comprises the water flow meter itself, mounted in a housing which is connected into the base so as to allow the flow of water from the mains supply, through the inlet pipe in the base, the water meter, the outlet pipe and finally back into the mains supply.

The base typically includes stop valves, to enable the water meter to be isolated from the mains supply. As an alternative, these valves may be provided in the mains supply itself, where not included in the base of the metering unit.

The meter housing is connected to the base of the unit in such a way as to be removable and replaceable, to allow the meter to be checked and serviced at regular intervals. A water filter will also typically be included in the housing, and this too needs regular servicing. The meter housing is thus conventionally connected to the base of the unit either by screwing the two parts together or by a "bayonet"-type fitting at the base of the meter housing. Both forms of connection are typically adapted to allow "concentric" water flow, i.e.

water enters the meter through one of, and exits to the base outlet pipe through another of, two concentric flow pipes, one positioned inside the other.

Removal and replacement of the water meter in its housing can be a time-consuming, and sometimes costly, operation. The whole of the housing needs to be disconnected from the base and either replaced after servicing or a fresh meter, in a new housing, installed. Since the meter housing is frequently made from brass or a similarly heavy metal alloy, its removal and replacement can be difficult and expensive.

In conventional water metering units, the connection between the meter housing and the base is typically sealed using one or more O-ring seals around the water inlet and outlet pipes.

A problem frequently encountered is that an O-ring seal can be dislocated by the rotating movement to which it is subjected when the housing is connected to the base, particularly in the case of a screw fitting. If an O-ring seal works loose from its correct position, water leakage can occur. This means that water may be consumed by the end user without passing through the meter itself, leading to inaccuracy in water meter readings. It is also relatively easy for an O-ring seal, positioned on the underside of the water meter housing, to fall out of its correct location when the housing is positioned vertically above the base prior to connecting the two. It is not always possible to tell that this has occurred when installing the meter housing.

Moreover, on screwing the meter housing into the base, mismatching of the screw threads can sometimes occur, causing thread interference and again increasing the chance of the seal between the two components being broken. This is particularly the case where a plastics material is used for the water meter housing and brass for the base of the unit.

The difficulties in fitting, removing and replacing the meter in its housing, on the base of a water metering unit, are exacerbated by the fact that the unit is frequently installed quite deep under the ground. For instance, some mains supply pipes and their associated metering units may be positioned up to 1 metre below the ground, so as to prevent freezing of the pipes in cold weather.

There is dissatisfaction with the current situation, in particular with regard to the problems encountered in sealing the meter housing-base interface. It would therefore be useful to provide a water metering unit in which these problems were overcome or at least mitigated, and which was also relatively cheap to manufacture. Ideally, the serviceable parts of the unit, such as the water meter itself and any filter incorporated in the unit, would be relatively easy to remove, check, service or clean and replace in the unit.

The desirability of providing such a unit is highlighted by the fact that approximately ten million water metering units are expected to be installed in the UK mains water supply over the next decade or so.

Statement of the Invention According to a first aspect of the present invention there is provided a water metering unit comprising a base member, the base member comprising a connecting portion adapted for connection into a water supply pipe and a housing portion capable of housing a water metering means, the connecting portion also having inlet and outlet means through which water from the supply pipe can be directed into and away from the housing portion; the unit additionally comprising an insert member capable of removable insertion into the housing portion of the base member, which insert member contains water flow metering means for measuring a volume of water passing through the metering means, and meter inlet and outlet means through which water entering the housing portion from the supply pipe can be directed to flow through the metering means and thence out of the housing portion.

The water metering means, and preferably other serviceable parts of the water metering unit, are thus carried in an insert member which is separate from the main housing. The housing portion can remain permanently in position wherever the unit is installed, and the water metering means can be removed and replaced relatively easily as and when required.

The metering means is kept separate from the high strength, somewhat bulky, housing which is needed to protect it when installed underground. The insert member itself, in which the water metering means is located, may be made of a relatively lightweight and low strength material, making removal and replacement of the metering means a relatively simple and inexpensive operation.

The housing portion of the base member is preferably integral with the connecting portion, so that the base member is of a single piece construction which can be connected into a water supply pipe and thereafter left in position even when other parts of the unit need to be serviced.

The base unit will conveniently be made from brass or some other high strength, durable material. The insert member, in contrast, is preferably made from a Water Research Councilapproved engineering plastics material such as polyoxymethacrylate, nylon or ABS.

The insert member preferably contains, in addition to the water metering means, a water filter, upstream of the water metering means in the direction of water flow through the unit when in use, to filter water entering the metering means. The insert member conveniently also contains one or more one-way check valves, downstream of the metering means, to prevent back-flow of water into the metering means.

The end of the insert member distant from the meter inlet and outlet means is preferably sealed by means of a sealing plate which, in use, prevents the escape of water which has entered the metering means.

The insert member is preferably adapted to be slid into place inside the housing portion of the base member, ideally such that its walls then sit flush with the inside walls of the housing portion. In order to ensure that the insert member is correctly located inside the housing portion, the insert member is preferably provided with a locating projection, such as a longitudinally extending flange, on its outer surface, which engages with a correspondingly shaped groove provided on the inner surface of the walls of the housing portion.

Both the insert member and the housing portion will typically be cylindrical in shape.

The advantage to be gained from sliding the insert member into position in the housing portion is that this reduces wear on any O-ring seals used to seal the join between the meter inlet and outlet means and the connecting portion of the base member. Such seals are then less likely to be dislocated from their correct positions, and the seal between the meter inlet and outlet means and the base member is more likely to remain intact.

The meter inlet and outlet means preferably comprise separate but adjacent conduits, leading into and out of the metering means inside the insert member. This is in contrast to the concentric inlet and outlet means of more conventional metering units. Naturally, when the insert member has been inserted into the housing portion, the inlet and outlet means in the connecting portion of the base member must correspond in position to the meter inlet and outlet means, so as to allow a through-flow of water from the water supply pipe and through the water metering means. At the interface between the meter inlet and outlet means and corresponding parts of the connecting portion, O-ring seals will preferably be provided in the insert member, and these will conveniently be located in grooves provided in the walls of the insert member, so as to further protect them from dislocation.

Any suitable water metering means may be contained in the insert member, although in the present invention a "piston"type or "multijet"-type of water meter (commonly available) is preferred.

If a water filter is contained in the insert member, this may also be of any conventional type. However, more preferably, the filter will comprise a main filtering surface for fitting inside a water conduit, and a secondary filter member of approximately frusto-conical cross-section, positioned upstream of the main filtering surface, such that sediment deposited on the main filtering surface is encouraged to fall back into the recesses between the secondary filter member and the internal walls of the conduit, when the main filter member is removed for cleaning. This type of filter is already known and commercially available.

The housing portion of the base member preferably comprises a removable end portion, into which can be fitted a display means for displaying a volume of water measured by the water metering means. This end portion can preferably be screwed into position at the end of the housing portion distant from the connecting portion of the base member, such that a suitable connection exists between the display means housed in the end portion and the water metering means housed in the main housing portion of the unit. Suitable display means, often known as counters, totalizers or registers, are also known and available, and are already adapted for connection to appropriate water metering means. The invention naturally provides within its scope a water metering unit as described above, in combination with display means located in an end portion removably fitted to the end of the housing portion.

The display means may comprise rotating dials, an LCD or LED display of numbers, or any other suitable read-out.

An openable cover is preferably fitted over the open end of the base member, typically over the above described end portion, to protect the display means or other components contained inside the metering unit. This cover is preferably transparent, to allow the display means to be read without removing the cover. It is preferably hinged to the base member to allow it to be opened and closed if necessary.

The connecting portion of the base member may be connected into a water supply pipe using any suitable fastening means, such as nuts, to connect the inlet and outlet means of the base member to appropriate parts of the supply pipe. Ideally, a quick-release fastening mechanism is used, to facilitate installation and removal of the water metering unit even below the ground. Suitable quick-release fastening means are well known.

The connecting portion preferably comprises a valve, upstream of the insert member in the direction of flow of water through the metering unit in use, which can be used to restrict or cut off the passage of water from the supply pipe into the water metering means. This valve is preferably a ball valve, and is ideally located in that part of the connecting portion which sits directly adjacent the insert member in use. This is in contrast to many conventional metering units, where, if the unit is thought of as an inverted T-shaped element, the crossbar of which runs parallel to the water supply pipe, such a valve would typically be positioned in the arms of the Tshape.

The connecting portion preferably also comprises a one-way check valve in its outlet means, to prevent back-flow of water from the supply pipe into the water metering means. Ideally, this acts in concert with a one-way check valve provided in the insert member itself, to provide added security against back-flow. However, alternatively, two check valves may be provided in the outlet means of the connecting portion, again for extra security.

The connecting portion of the base member preferably comprises means by which the base member can be secured into place in an outer housing, which might typically be inserted into the ground to house and protect the entire water metering unit.

These means may comprise, for instance, one or more lugs on the underside of the base member, adapted to receive bolts or similar fastening means.

According to a second aspect of the present invention, there is provided an insert member for removable insertion into a water metering unit as described above as being in accordance with the invention, the insert member containing water flow metering means for measuring a volume of water passing through the metering means, and meter inlet and outlet means through which water can be directed to flow, in use, through the metering means.

According to a third aspect of the invention, there is provided a base member for use in the water metering unit of the invention, the base member comprising a connecting portion adapted for connection into a water supply pipe and a housing portion capable of housing water metering means, the connecting portion having inlet and outlet means through which water from the supply pipe can be directed into and away from the housing portion. The connecting portion is preferably integral with the housing portion of the base member.

In the metering unit of the present invention, insertion and removal of the insert member can usually be performed manually with relative ease. However, the operation may be facilitated using a specially adapted pair of tongs which comprises two arms, at least one of which is movable relative to the other and which are biased in a direction away from one another, and means such as a lever by which the two arms may be brought together so as to be capable of gripping the insert member of the unit. Recesses may be provided at appropriate positions on the outside of the insert member, to accommodate cooperating projections on the arms of the tongs. The tongs can thus be used to take hold of the insert member, either to place it inside or to remove it from the housing portion of the unit.

The present invention will now be described, by way of example only and with reference to the accompanying drawings, of which: - - Fig 1 is a cross-sectional view of a water metering unit in accordance with the invention; - Fig 2 is an end view of the unit shown in Fig 1; - Fig 3 is a plan view of the unit shown in Figs 1 and 2; and - Fig 4 is an underplan view of the unit shown in Figs 1-3.

Detailed Description of the Drawings Referring firstly to Fig 1, the water metering unit shown in cross-section comprises a single piece brass base member having a connecting portion 1 and an integral upstanding housing portion 3. This base member is connected into a mains water supply pipe 5, to which it is fastened at each side by means of nuts 7. The metering unit is typically fitted into the mains supply upstream of an outlet for which water consumption is to be metered.

The connecting portion 1 comprises an inlet water conduit 9 and an outlet conduit 11. On-off ball valve 13 is positioned in the inlet conduit 9 and is operable to either allow or prevent flow of water from the mains pipe 5 into the housing portion of the unit. A one-way check valve 15 is located in the outlet conduit 11, downstream of the housing portion 3, and serves to prevent back-flow of water from the mains pipe 5 into the housing portion. This is important not only to ensure an accurate meter reading, but also to isolate water in the metering unit or in the rest of the mains supply from possibly contaminated water at the outlet point.

Located inside the housing portion 3 of the base member of the unit is an insert member 17, made from an approved engineering plastics material such as polyoxymethacrylate, nylon or ABS.

The insert member is cylindrical in shape, as is the housing portion 3, and has been inserted so that its walls sit flush with the internal surfaces of the walls of the housing portion. To assist in its accurate location inside the housing portion, the insert member 17 carries on its outer surface a longitudinally extending flange (not seen), which locates in an appropriately positioned groove cut into the internal walls of the housing portion 3.

As seen from Fig 1, the insert member 17 is positioned inside housing portion 3 such that its inlet conduit 19 connects with conduit 9 in the connecting portion and its outlet conduit 21 connects with conduit 11 in the connecting portion. The two conduits 19 and 21 are separate and adjacent one another. The interfaces between conduits 19 and 21 in the insert member and conduits 9 and 11 respectively in the connecting portion are sealed by means of O-ring seals 23 and 25 respectively. These O-rings are positioned in grooves in the walls of insert member 17, such that when 17 is slid downwardly to fit inside the housing portion 3, O-rings 23 and 25 are not displaced from their correct positions. Moreover, since the insert member is slid into position and no rotation is needed to fit it into the base member of the unit, the O-rings 23 and 25 are protected from undue wear and tear.

The inside walls of the housing portion are very precisely machined to accept the O-rings 23 and 25.

The insert member 17 contains a water filter 27, a piston-type water meter 29 and a one-way check valve 31. At its upper end it is sealed by means of sealing plate 33, which snap fits onto the main body of 17 and separates wet regions of the metering unit from the "dry" regions above.

The water filter 27 comprises a main filter, generally hemispherical in shape, which sits inside the inlet conduit 19 of the insert member 17. Additionally, the filter comprises a frusto-conical insert 35, which extends upwardly, tapering towards the top of the main part of the filter, in use. When the main part of the filter is removed for cleaning or replacement, sediments deposited on its undersurface will fall down into the annular recess between the base of the conical insert 35 and the internal walls of conduit 19. This allows the filter to be serviced and cleaned relatively easily, without undue spillage of sediment.

Water flows through the metering unit illustrated in Fig 1 in the direction shown by the arrows. It passes from the mains supply pipe 5, through inlet conduit 9, ball valve 13 (if open), inlet conduit 19 of the insert member 17, through the water filter 27 and into chamber 37 of the water meter 29.

A rotating element labelled 39 rotates in chamber 37 about pin 41, thus executing an eccentric movement. When element 39 is in the position shown in Fig 1, a volume of water enters chamber 37 from the conduit 19. When element 39 has rotated through a further 180q this volume of water has been pushed from one side of chamber 37 to the other, and is then able to discharge into outlet conduit 21. This rotation of the element 39, which represents the flow of a fixed volume of water through the water meter, causes, by means of a magnetic coupling (not shown), corresponding rotation of a spindle in the counter or totalizer 43.Counter 43 is not illustrated in detail in Fig 1, but is of conventional construction and provides a visible display of the quantity of water passing through the metering unit, which display is visible through the transparent cover 44 of the counter when 45, fitted across the upper end of the unit is raised.

Water leaving the meter 29 passes through the check valve 31, which again prevents back-flow of water into the meter. Valve 31 acts in concert with valve 15 in the conduit 11 in the connecting portion of the unit.

At the upper end of the housing portion 3, above the insert member 17, a brass headring 47 is screwed into position over the housing portion. The counter 43 is fitted to the inside of the headring. 49 is the point at which cover 45 is hingedly connected to the headring 47, so as to allow its opening and closure.

The reference numeral 51 refers to a reinforcing web on the outside of the base member of the unit, which generally strengthens the unit. 34 is a retaining ring to hold sealing plate 33 in position in the housing portion. 53 is a lead seal, optionally fitted to the unit as a tamper-proof mechanism. The seal would typically be fitted once the unit had been tested and approved by the appropriate authority, and its subsequent removal would indicate that the unit had been tampered with in some way. The seal 53 is secured to headring 47 and to one of the strengthening webs 51.

A number of lugs 55 on the underside of the connecting portion 1 are used to receive bolts if the metering unit is to be secured in position in an outer housing.

In use, the water metering unit shown in Fig 1 is connected into the mains supply pipe 5, upstream of an outlet, such as a house or factory, at which water from the mains supply is consumed. The base member of the unit is secured into position by means of nuts 7, and possibly also secured into the base of an outer housing in which the unit is located so as to protect it from ingress of water and debris. Typically, the supply pipe 5 will be up to one metre below the ground, and hence it is to this depth that the metering unit must be installed.

Having installed the base member of the unit, insert member 17 (carrying water filter 27, meter 29 and check valve 31) is slid into position inside the housing portion 3 of the base member, using the locating flange on the insert member and the corresponding groove on the inside of the housing portion to effect accurate location. Once the insert member has been slid firmly into position, a sealed (by means of O-rings 23 and 25) connection has been effected between the inlet and outlet conduits 19 and 21 of the insert member 17, and the corresponding conduits 9 and 11 of the base member. During installation of the insert portion 17, ball valve 13 is retained in its closed position so as to isolate the water meter 29 from the mains supply.Back-flow of water from the supply pipe into the housing portion 3 is prevented by check valve 15 and, later, by check valve 31 provided in the insert member 17.

Once the insert member has been inserted into the housing portion 3, headring 47 (containing the counter 43) is screwed into position at the top of the housing portion 3, with lid 45 closed. Sealing plate 33 ensures that the counter and all regions above the insert member 17 remain dry, even when water is allowed to flow through the meter 29.

Water flow is reinstated by opening the ball valve 13, and allowing water from the mains supply pipe 5 to flow through water filter 27, meter 29, valves 31 and 15, and thence back into the supply pipe and on to the outlet at which water is being consumed.

It is necessary at regular intervals to clean or replace the water filter 27, and to service the water meter 29 to ensure its continuing accurate operation. The piston forming part of the meter 29 can become damaged with use, and may need to be replaced. Also, the check valve 31 may need to be checked and serviced at regular intervals.

In order to carry out any of the above operations, headring 47 is unscrewed from housing portion 3 and removed, and the insert member 17 is then slid out of the housing portion 3 and taken away for appropriate servicing, replacement or cleaning of parts. The base member of the unit, including the housing portion 3 and connecting portion 1, remains in position in the supply pipe 5; only the insert member 17 need be removed.

Ball valve 13 is closed prior to removal of the insert member 17.

Following servicing, the restored insert member 17, or a ready-tested replacement, is positioned inside housing portion 3, headring 47 replaced and ball valve 13 opened to reinstate the flow of water through the metering unit. The whole operation is relatively simple to perform, and because there is no need to replace a complete housing each time constituent components of the unit are serviced or replaced, also relatively inexpensive.

Insertion and removal of the member 17 may be carried out using a specially adapted pair of tongs, the arms of which grip the outside of member 17 by locating in recesses 57 provided at the top of the insert member. The two arms of the tongs are biased apart (for instance by means of a spring) and the tongs will typically be provided with a lever or similar means by which the arms can be brought together to grip the insert member 17 and hence to push it into or pull it out of its housing portion 3.

Fig 2 shows a view from one end of the outside of the metering unit shown in Fig 1. Reference numerals used are the same as those for Fig 1, with the addition of 59, which represents a handle by which ball valve 13 is operated to open or close.

Fig 3 is a plan view of the metering unit shown in Figs 1 and 2, and Fig 4 a part underplan of the unit. In Fig 3, details of the counter 43, the readout of which would normally be visible through transparent counter cover 44 when lid 45 is lifted, has been omitted. In Fig 4, lugs 55 can be seen on the undersurface of the base member of the unit, which would be used to connect the base member to an outer housing for the unit.

A metering unit in accordance with the invention, and of the type of which Figs 1-4 show an example, is relatively easy and inexpensive both to construct and to install. The insert member, containing functional components such as the water meter itself, a water filter, etc can be made relatively compact, thus reducing the overall size of the unit compared to that of conventional units. For instance, the housing portion 3 of the unit illustrated in Figs 1-4 is much shorter than meter housings in most conventional units.

The invention provides a base member (1 and 3 together in Figs 1-4), for connection into a mains water supply. The invention also provides an insert member such as 17 in Figs 1-4, containing all necessary working components, which can be inserted into an already installed base member. Further, the invention provides a ready assembled water metering unit, which comprises a base member into which has been inserted an insert member containing a water meter. Worn out or damaged insert members can be removed, destroyed and replaced with spares such as are provided by the present invention.

Claims (17)

1. A water metering unit comprising a base member, the base member comprising a connecting portion adapted for connection into a water supply pipe and a housing portion capable of housing a water metering means, the connecting portion also having inlet and outlet means through which water from the supply pipe can be directed into and away from the housing portion; the unit additionally comprising an insert member capable of removable insertion into the housing portion of the base member, which insert member contains water flow metering means for measuring a volume of water passing through the metering means, and meter inlet and outlet means through which water entering the housing portion from the supply pipe can be directed to flow through the metering means and thence out of the housing portion.

2. A water metering unit according to claim 1 in which the housing portion is integral with the connecting portion.

3. A water metering unit according to claim 1 or claim 2 in which the insert member contains, in addition to the water metering means, a water filter, upstream of the water metering means in the direction of water flow through the unit when in use, to filter water entering the metering means.

4. A water metering unit according to claim 3 in which the insert member contains one or more one-way check valves, downstream of the metering means, to prevent back-flow of water into the metering means.

5. A water metering unit according to any of the preceding claims in which the end of the insert member distant from the water inlet and outlet means is sealed by means of a sealing plate which, in use, prevents the escape of water which has entered the metering means.

6. A water metering unit in which the insert member is adapted to be slid into place inside the housing portion of the base member.

7. A water metering unit according to claim 6 in which the insert member is provided with a locating projection on its outer surface which engages with a correspondingly shaped groove provided on the inner surface of the walls of the housing portion.

8. A water metering unit according to any of the preceding claims in which the meter inlet and outlet means comprise separate but adjacent conduits, leading into and out of the metering means inside the insert member.

9. A water metering unit according to claim 8 in which at the interface between the meter inlet and outlet means and corresponding parts of the connecting portion, 0 ring seals are provided in the insert member.

10. An insert member for removable insertion into a water metering unit as claimed in any of the preceding claims.

11. A base member for use in a water metering unit as claimed in any of claims 1 to 9, the base member comprising a connecting portion adapted for connection into a water supply pipe and a housing portion capable of housing water metering means, the connecting portion having inlet and outlet means through which water from the supply pipe can be directed into and away from the housing portion.

12. A water metering unit according to claim 1 and substantially as herein described.

13. A water metering unit substantially as described with reference to the accompanying drawings.

14. An insert member as claimed in claim 10 and substantially as herein described.

15. An insert member for removable installation into a water metering unit, the insert member being substantially as described with reference to the accompanying drawings.

16. A base member according to claim 11 and substantially as herein described.

17. A base member for use in a water metering unit and substantially as described with reference to the accompanying drawings.