GB2286975A

GB2286975A - In-line meter assembly

Info

Publication number: GB2286975A
Application number: GB9503710A
Authority: GB
Inventors: Gerald John Evans
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-03-03
Filing date: 1995-02-24
Publication date: 1995-09-06
Anticipated expiration: 2015-02-24
Also published as: GB2286975B; GB9503710D0

Abstract

An in-line meter assembly has a first casing part 10 which contains metering components 16, 18, the metering components 16, 18 being held in the first casing part 10 by a locking ring 22. A second casing part 12 is secured to the first casing part 10 and has an inlet flow-way 32. There is an outlet flow-way in the first casing part 10 on the opposite side of the metering components from the inlet flow-way 32. A filter 26 is mounted between the inlet flow-way 32 and the locking ring. Hence, when it is necessary to inspect and/or clean the filter 26, the two casing parts 10, 12 can be separated, and the filter 26 removed, without disturbing the integrity of the unit defined by the first casing part 10, the metering components 16, 18 and the locking ring. Therefore, the metering components 16, 18 do not need to be recalibrated when the filter is removed. <IMAGE>

Description

IN-LINE METER ASSEMBLY The present invention relates a meter assembly in which fluid enters a casing of the assembly of one side of the metering components, passes through those metering components, leave the casing through an outlet on the opposite side of the metering components. Such an assembly is known as a "inline" arrangement. The present invention relates particularly, but not exclusively, to the case where such an assembly -incorporates a water meter.

Such in-line meter assemblies are to be contrasted with the meter assemblies show in e.g. my UK patent application number 9420431.0, in which fluid enters the casing of the assembly on one side of the meter components, passes through those meter components, and leaves the casing through an outlet on the same side of the metering components.

Standard in-line meter assemblies have an outer casing formed by two parts threadably secured together. One part of the casing has an inlet flowway which opens into the interior of the casing and is secured to an inlet pipe, and the other part of the casing has an outlet flow-way and is secured to an outlet pipe. In general, the inlet and outlet flow-ways are coaxial. Within the casing are the metering components which measure the fluid flow through the casing from the inlet pipe to the outlet pipe. The casing is shaped to hold the metering components in place, and to prevent fluid flow around, rather than through, the metering components.

It is also known to provide a filter within the casing which lies in the flow-path of fluid between the inlet flow-way and the metering components.

Such an arrangement can reduce or prevent debris entrained in the fluid flow in the inlet pipe contaminating the metering components. As debris collects on the filter, it will act as a restriction to fluid flow to the meter assembly, and this can reach levels which will prevent the meter from operating correctly. Therefore, it is necessary periodically to inspect, and if necessary clean, the filter. To do this, the two parts of the casing are separated, giving access to the filter and the metering components. The filter can then be cleaned easily. However, such removal of the filter also releases the meter components, which must therefore be re-calibrated when the meter assembly is reassembled for subsequent use. This is inconvenient and costly since it prevents rapid return of the meter assembly to its position between the inlet and outlet flow pipe when the filter needs to be inspected or cleaned.

Therefore, at its most general, the present invention proposes that there is a locking means, such as a locking ring, which is directly or indirectly securable to a part of the casing and which then holds the meter components within that part of the casing. The filter may then be positioned on the opposite side of the locking ring from the metering components, possibly being held in place by a further part of the casing or alternatively by another component.

With such an arrangement separation of the two parts of the casing permits access to the filter for inspection for and/or cleaning. However, because the locking ring prevents any access to the metering components, it is not necessary to re-calibrate the meter after the filter has been replaced. In principle, the filter may be at any position between the inlet flow-way and the locking ring. It could, for example, be mounted in a part of the casing which does not contain the metering components.

However, it will normally be possible for the filter to be mounted immediately adjacent the locking ring since it is not then necessary to shape the casing to support the filter, merely to hold it in place.

Preferably, means are provided to prevent tampering with the locking ring when it is in place.

The locking ring may be fitted to the casing by threaded or bayonet arrangements or other suitable means, but it is important that it cannot be accidentally released from the casing, since that would then need re-calibration of the metering components. Any anti-tampering arrangement is suitable, such as those already known for securing together the parts of the casing in existing in-line meter assemblies.

An embodiment of the present invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which the sole figure shows a crosE sectional view through a meter assembly according to the present invention.

Referring to the figure, a meter assembly has first casing part 10 which is threadably secured to a second casing part 12. The first casing part 10 has an outlet flow-way 14 at one end thereof, and the other end opens into the interior of the second casing 12. Within the first casing part 10 is a meter piston arrangement 16 which is driven by fluid flow passing therethrough and drives a counter 18.

The piston arrangement 16 and the counter 18 form the metering components of the meter assembly, and may be conventional.

The piston arrangement 16 is held in place by a spacer ring 20 which is sealed (e.g. by O-rings) to the piston 16 and the first casing part 10. The spacer 20, and hence the metering component 16 are held in place within the first casing part 10 by a locking ring 22 which is threadably secured to the first casing part 20. Hence, the first casing part 10, the metering components 16, 18, the spacer 20 and the locking ring 22 form a unit which can be detached from the second casing part 12 without affecting the metering components 16, 18. Hence, that unit can be removed from, and replaced on, the second casing part 12 without the metering components 16, 18 needing re-calibrating. Indeed, the spacer ring 20 and the locking ring 22 could be made integral.

Preferably, means are provided to prevent the locking ring 22 being removed from the first casing part 10. For example, a wire loop (not shown) may pass between a ring on the interior of the first casing part 10 and a ring on the locking ring 22, so that there will be an immediate visual indication (by breakage of the wire) if there has been tampering with the locking ring 22. The locking ring 20 may alternatively be connected by e.g. a wire loop to the spacer ring 20, provided the latter is firmly sealed to the first casing part 10.

As shown in the figure, the locking ring 22 has openings 24 therein which permit fluid to pass therethrough to reach the metering components.

Those openings 24 are covered by a filter 26, which is held in place by a step 28 in the first casing part 10 and a shoulder 30 of the second casing part 12.

In operation, the second casing part 12 is connected to an inlet pipe (not shown), via an inlet flow-way 32, and the outlet flow-way 14 is connected to an outlet pipe (not shown). The fluid then flows into the interior of the casing through the inlet flow-way 32, through the filter 26, through the openings 24 in the locking ring 22, through the piston 16, and out of the casing through the outlet 14. When it is necessary to inspect and/or clean the filter, the meter assembly is detached from the inlet and outlet pipes, and the second casing part 12 unscrewed from the first casing part 10. The filter 26 can then be lifted off the locking ring 24. It is then straightforward to re-position a replacement filter, screw the second casing part 12 onto the first casing part 10, and re-position the meter assembly between the inlet and outlet pipes.

The filter that has been removed can then be cleaned later. In this way, the time for which no flow can pass through the inlet and outlet pipes is minimised.

In the embodiment shown in the figure, the inlet and outlet flow-ways 14,32 are coaxial. The present invention is not limited to this, but they must be on opposite sides of the metering components 16,18 since the present invention is concerned with an in-line meter assembly.

The figure also shows that the interior of the second casing part 12 has an upstanding wall 34 through which passes the inlet flow-way 32. That upstanding wall 32 defines, together with the adjacent parts of the second casing part 12, a recess 36 which surrounds the inlet flow-way 32. As fluid passes from the inlet flow-way 32 to the interior of the second casing part 12, the increase in diameter of the flow slows that flow and therefore particles entrained in that flow will tend to be deposited in the recesses 36, before those particles reach the filter 26. This then slows the clogging of the filter 26. Furthermore, when there is no flow through the meter assembly, particles adhering to the filter 26 will tend to fall therefrom, into the recess 36. Once in those recesses, they are less likely to be entrained in fluid flow when flow through the meter assembly recommences. Note that there may be a single recess 36 extending circumferentially around the inlet flow-way 32, or a plurality of recesses separated by internal walls within the second casing part 12.

This arrangement is similar to recesses for collecting particles described in my UK patent application number 9420431.0.

Claims

1. An in-line meter assembly detachably connected between an inlet pipe and an outlet pipe, the meter assembly having a first casing part having an outlet flow-way releasably connected to the outlet pipe, metering components in the first casing part, a locking means to secure the metering components in the first casing part, a second casing part releasably secured to the first casing part and having an inlet flow-way releasably connected to the inlet pipe, and a filter between the inlet flow-way and the locking means, the outlet flow-way being on the opposite side of the metering components to the locking means.

2. An in-line meter assembly according to claim 1, wherein the locking means is a locking ring which engages an internal wall of the first casing part.

3. An in-line meter according to claim 2, wherein there is a spacer between the locking ring and the metering components, the spacer sealing the metering components to the internal wall of the first casing part.

4. An in-line meter according to claim 2 or claim 3, wherein the filter is mounted immediately adjacent the locking ring.

5. An in-line meter according to any one of claims 1 to 3, wherein the filter is supported in the second casing part.

6. An in-line meter assembly according to any one of the preceding claims, wherein the second casing part has at least one upwardly facing recess for entrapping particles.

7. An in-line meter assembly according to claim 6, wherein the recess(es) extend around the inlet flowway.

8. An in-line meter assembly substantially as herein described with reference to and as illustrated in the accompanying drawing.

9. An in-line meter assembly connectable between an inlet pipe and an outlet pipe, the meter assembly having a first casing part having an outlet flowway, metering components in the first casing part, a locking means to secure the metering components in the first casing part, a second casing part releasably secured to the first casing part and having an inlet flow-way, and a filter between the inlet flow-way and the locking means, the outlet flow-way being on the opposite side of the metering components to the locking means.