GB2246158A

GB2246158A - Boundary box

Info

Publication number: GB2246158A
Application number: GB9015907A
Authority: GB
Inventors: Trevor Reginald Smith; Andrew Welfare
Original assignee: Wask RMF Ltd
Current assignee: Glynwed Pipe Systems Ltd
Priority date: 1990-07-19
Filing date: 1990-07-19
Publication date: 1992-01-22
Also published as: GB9015907D0

Abstract

An inspection housing for a device such as a water meter, comprising an elongate chamber within which the device is to be housed. An entry passageway penetrates into the chamber, the entry passageway opening at one end into the chamber. The passageway extends at that one end parallel to or at a small angle of inclination to an axis parallel to the length of the chamber. The passageway at the other end extends in a direction perpendicular to or at a large angle of inclination to the said axis. The passageway is curved such that a flexible conduit can be passed therethrough for connection to a device mounted within the chamber. Thus the position of a device such as a water meter along the length of the chamber can be selected to suit the prevailing circumstances. The device is suitably mounted in a piston structure which sealingly engages the interior of the chamber to prevent any leakage into the portion of the chamber within which the device is located. <IMAGE>

Description

INSPECTION HOUSING The present invention relates to an inspection housing for a device such as a water meter which is connected in a water supply service pipe. In the water industry such inspection housings are generally referred to as "boundary boxes".

Water meters are used to record the amount of water which passes through service pipes in which they are connected. Access to the meters is an important factor as readings have to be taken periodically to ascertain the volume of water a subscriber has used and to charge him accordingly.

One particular problem in this field is that the depth of the service pipe below the ground is variable, yet the water meter itself has to be at a depth to facilitate reading and maintenance. If the meter is simply connected in line with the service pipe, the depth of the meter below the surface depends on the depth of the pipe. Thus if a water meter is simply connected in line with a service pipe that is buried at a relatively great depth, it will be difficult or impossible to read and service the meter.

One known solution to this problem is to use a meter inspection housing in which the meter is connected to two tightly coiled lengths of connection pipe. The meter is connected in series with the service pipe by making appropriate connections between the connection pipes and the service pipes. The coils of connection pipe are housed in a cylindrical casing such that each pipe defines a helix the axis of which corresponds to the axis of the cylindrical casing. The minimum diameter of the casing is a function of the diameter of the coils formed by the connection pipes. Unfortunately the coil diameter is inevitably relatively large even if special components of relatively high flexibility are used.

It is an object of the present invention to obviate or mitigate the problems outlined above.

According to the present invention, there is provided an inspection housing for a device, comprising an elongate chamber within which the device is to be housed, and at least one entry passageway penetrating into the chamber, the or each entry passageway opening at one end into the chamber and extending at that one end parallel to or at a small angle of inclination to an axis parallel to the length of the chamber, the or each entry passageway at the other end extending in a direction perpendicular to or at a large angle of inclination to the said axis, and the entry passageway being curved such that a flexible conduit can be passed therethrough for connection to a device mounted within the chamber.

Thus the position of a device such as a water meter along the length of the chamber can be selected to suit the prevailing circumstances. If the meter is connected to two connecting pipes extending through respective entry passageways, displacement of the meter along the length of the chamber is accommodated by sliding movement of the connecting pipes within the entry passageways. Once the vertical position has been adjusted the connecting pipes can then be connected to a service pipe.

The device may be mounted in a piston arrangement which sealingly engages the interior of the chamber to prevent any leakage into the portion of the chamber within which the device is located.

Preferably means are provided for locking the piston structure in position relative to the chamber. The locking means may comprise at least one cam mounted on the piston structure and rotatable to engage the wall of the chamber.

Preferably a manually actuable valve is provided in the piston structure to enable fluid gathered around the device to be drained out into lower portions of the chamber.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal part-sectional view of a water meter mounted in an embodiment of the present invention; Figure 2 is a top-flange view of a piston structure incorporated in the embodiment of Figure 1; Figure 3 is a sectional view on line 3-3 of Figure 2; Figure 4 is a sectional view of a locking device mounted in the piston structure of Figure 2; and Figure 5 is a sectional view of a dewatering valve mounted in the piston structure of Figure 2.

Referring to Figure 1, the illustrated embodiment of the invention comprises an inspection housing in the form of a cylindrical casing 1 closed at its upper end by a cap 2 having a removable cover 3 and closed at its lower end by a base 4. The cap 2 is provided with a seal 5 to prevent water leaking into the casing 1 therearound. The base 4 supports a pair of ducts 6 each of which defines a curved entry passageway receiving a respective connection pipe 7.

A water meter 8 is mounted on a piston structure 9 that is slidable along the length of the casing 1 and is provided with a Oring seal 10. The position of the meter along the length of the casing 1 can thus be adjusted by pulling it and the piston to which it is connected along the length of the casing. The connecting pipes 7 which are connected to the meter through the piston 9 are sufficiently flexible so as to move along the lengths of the ducts 6 to permit axial movement of the meter relative to the casing. As described in more detail below, the piston structure 9 supports locking devices to enable the position of the piston relative to the casing to be fixed.

In use, the described assembly is dropped into a hole in the bottom of which the service pipe to which the meter is to be connected is exposed. In Figure 1, the vertical level of the service pipe is assumed to correspond to the line 11. Thus the pipe is exposed and the base 4 is positioned in the bottom of the excavation.

The casing 1 is arranged substantially vertically. The pipes 7 extend substantially parallel to the casing axis at the ends of the entry passageways within the casing and substantially perpendicular to the casing axis at the ends of the entry passageways remote from the interior of the casing. Thus the ends of the pipes 7 projecting outside the base extend substantially parallel to the service pipe to which they are to be connected. The connecting pipe 7 can thus be easily connected to the ends of the service pipe using conventional couplings of any desired type. Before connection however the casing 1 is cut to an appropriate length so that when the cap 2 is positioned on the casing the cover 3 is at ground level, that is the level indicated in Figure 1 by line 12.It will be appreciated that the length of the casing 1 is designed to be sufficient for all possible depths of a service pipe below ground level. When installed, the length of the casing 1 is simply reduced to suit local conditions by cutting off its open end. The meter is then positioned so that its depth relative to ground level is as desired. The service pipe and/or connection pipes 7 are then cut to length to facilitate easy interconnection.

Because of the simple base structure incorporating the gradually curved ducts 6 pipes of for example polyethylene can be used for the connecting pipes 7. It is not necessary to coil the connection pipes and therefore the diameter of the casing 1 can be as small as is appropriate given that it has to accommodate the meter 8.

Referring now to Figures 2 and 3, this illustrates the piston structure 9 in greater detail. The O-ring 10 extends in a perpheral groove around the circular piston 9. Two spigots 13 are provided to which the connection pipes 7 are connected. In the illustrated case the spigots 13 are provided with grooves 14 into which the material of the connection pipes is compressed by collars 15 (Figure 1). The water meter 8 is then secured to the piston 9 so as to communicate with the spigots 13. The water meter is not illustrated in detail as its structure is not directly relevant to the present invention.

The piston 9 supports three cam locking devices each comprising a toothed cam 16 mounted on a stub 17 that extends through the piston 9 as shown in Figure 4. An O-ring 18 prevents fluid leaking around the stub 17. Rotation of the square end of the stub from one side of the piston 9 causes the cam 16 to rotate into contact with the wall of the casing 1, the teeth of the cam then resisting any movement of the piston 9 relative to the casing. Thus once the meter has been positioned at a appropriate depth it and the piston 9 on which it is supported is locked in position by rotation of the three cam locking devices.

Referring now to Figure 5, this illustrates the structure of a blow-off valve 19. This comprises a valve member supporting an- Oring 20 and bias to a closed position by compression spring 21. If therefore fluid builds up above the piston 9 it can be drained out beneath the piston simply by pushing the valve member downwards.

Equally if pressure builds up beneath the piston 9 it can be released by depressing the valve member.

Figure 2 illustrates the main component of the piston structure from which have been stripped the O-ring 10, the cam locking device and the blow-off/dewatering valve. In Figure 2 numeral 22 identifies three apertures each intended to receive a respective cam locking device and numeral 23 identifies an aperture intended to receive a blow-off/dewatering valve. Numeral 24 identifies one of an array of six bolt holes which enable the piston structure to be secured to a water meter and numeral 25 identifies one of an array of strengthening ribs that are also shown in Figure 3.

In the illustrated embodiment the ducts 6 deflect the connection pipes 7 through 900 so that whereas the ends of the connection pipes within the chamber defined by the casing 1 extend parallel to the axis of that chamber the ends of the connection pipe 7 outside the casing extend perpendicular to the casing axis. It will be appreciated that the inclination of the ducts 6 within the casing may deviate somewhat from parallel to the casing axis providing connection pipes passed therethrough can be conveniently connected to the water meter or other device. Equally it will be appreciated that the ends of the ducts 6 from which the pipe 7 project outside the casing need not be perpendicular to the casing axis. Indeed all that is required that the connection pipes 7 are directed in the general direction of the service pipe to which they are to be connected given that there is some flexibility in the pipes 7 and generally in the service pipe to which they are to be connected.

Claims

1. An inspection housing for a device, comprising an elongate chamber within which the device is to be housed, and at least one entry passageway penetrating into the chamber, the or each entry passageway opening at one end into the chamber and extending at that one end parallel to or at a small angle of inclination to an axis parallel to the length of the chamber, the or each entry passageway at the other end extending in a direction perpendicular to or at a large angle of inclination to the said axis, and the entry passageway being curved such that a flexible conduit can be passed therethrough for connection to a device mounted within the chamber.

2. An inspection housing incorporating a said device in the form of a water meter connected to two connecting pipes extending through respective entry passageways.

3. An inspection housing according to claim 1 or 2, wherein the device is mounted in a piston structure which sealingly engages the interior of the chamber to prevent any leakage into the portion of the chamber within which the device is located.

4. An inspection housing according to claim 3, wherein means are provided for locking the piston structure in position relative to the chamber.

5. An inspection housing according to claim 4, wherein the locking means comprises at least one cam mounted on the piston structure and rotatable to engage the wall of the chamber.

6. An inspection housing according to claim 3, 4 or 5, wherein a manually actuable valve is provided in the piston structure to enable fluid gathered around the device to be drained out into lower portions of the chamber.

7. An inspection housing substantially as hereinbefore described with reference to the accompanying drawings.