WO2005043091A1

WO2005043091A1 - Fluid consumption meter using a rotating impeller

Info

Publication number: WO2005043091A1
Application number: PCT/IL2004/000970
Authority: WO
Inventors: Ilan Paz
Original assignee: S.F.M. Sophisticated Flow Meters Ltd.
Priority date: 2003-11-02
Filing date: 2004-10-25
Publication date: 2005-05-12
Also published as: IL158710A0

Abstract

The invention provides a flow-through fluid consumption meter (10) of the type having a chamber (12) in which a rotatable part (14) is revolved by fluid flowing through the chamber (12), the rotatable part (14) being rigidly attached proximate to a first end of a shaft (16), whereby proximate to an opposite second end of the shaft (16) there is rigidly attached an opaque rotor (20) having a partially cut-away surface (22), which rotor (20) revolves via the shaft (16) with the fluid-driven rotatable part (14), the rotor (20) being positioned between an optical transmitter (28) -receiver (30) pair which detects the blocking presence of the surface and the non-blocking cut-away area (32) of the rotor surface, and the optical transmitter-receiver pair (28), (30) is electronically connected to an information processing unit (38) arranged to receive and record data regarding the revolution of the rotor (20).

Description

FLUID CONSUMPTION METER USING A ROTATING IMPELLER

The present .invention relates to the metering of fluids. More particularly, the invention provides an electronic meter for water, fuel and other fluids, the meter recording consumption with improved accuracy and being compatible with remote reading systems. Due to population increases not being balanced by increased supply, drinking-quality water is becoming an increasingly scarce and expensive resource. Accordingly local water supply authorities are making efforts to receive all payments due to them for this service. 'Water suppliers always suffer a gap between the total quantity of water supplied and the quantity being paid for by consumers according to the sum of all readings- of water meters installed in a defined network. A part of this unaccounted water is lost by leakage, and some even by outright theft; solutions to such problems lie in the fields of maintenance and law enforcement. However local authorities are beginning to recognize that inaccurate meters, particularly meters failing to record very low flows, are also part of the problem. Meter accuracy is important because a fast meter can be the cause of legal action by consumers while a slow meter causes direct monetary loss to the supplier. The demand for water meters has risen as one consequence of the higher water prices. While in the past landlords have charged tenants a fixed sum for water use, modern practice - in some areas mandated by law - is that each individual apartment in a housing block be supplied with its own water meter, thus providing an incentive to consumers to prevent wastage. The standard water meter, still in extensive use today, comprises a gear- driven numerical display, the gears being driven by some type of turbine or impeller installed in the fluid flow passing through the meter housing., The gear driven numerical registry is kept separate from the wetted part of the meter, and the interconnecting drive therebetween is typically based on a magnetic link. Meters of this type provide a simple and low-cost solution yet have a number of shortcomings. One of these is failure to monitor very slow flows due to static friction in the gear train and related mechanisms. A further problem is an inability of such meters to communicate with AMR (Automatic Meter Reading) systems, unless a magnetically operated reed switch is added to the meter together with the appropriate electronic circuits. Lastly there is the problem of water-borne particulate matter damaging the immersed gears. Regarding the AMR systems, these may be based on telephone or wireless, each having its drawbacks. In practice most utilities use a hybrid communication system. While manual meter reading is still unavoidable in some areas, much such work will have to be rescheduled to the evening hours. Due to changes in lifestyles, the meters in many homes are inaccessible during the day when all adults work outside the home, the meter reader often being greeted by a guard dog. Data collection by AMR overcomes the problem and is cheaper and thus can be carried out more frequently to monitor consumption patterns and allow the supplying utility to plan responses thereto. Frequent meter reading also enables the supplier to offer differential pricing and "smart house" features. The state of the art can be assessed by review of the following recent US patents. In US Patent no. 4,798,092, Lagergren et al. disclose a flow meter where the housing includes a turbine having one or more magnetic blades. An adjacent conductor coil and oscillator generate a RF signal in the coil as the turbine revolves. The signal is filtered and processed to generate flow rate estimates, which after temperature adjustment appear on a display. Bultrau in US Patent no. 5,187,989 discloses a device having a series of proximity sensor for detecting the direction of rotation of an immersed spinner. A mark is fixed to the rotary element, and a selector controls which proximity sensor is active. Silverman et al. in US Patent no. 5,540,107 propose a magnet encapsulated in an impeller blade to produce a flow-meter similar in principle to the '092 patent. Castillo proposes an electronic correction system in US Patent no. 5,574,229 to improve proportionality between flow and registered flow, using a factor extracted from a database. The system then effects corrections and supplies the new reading of water consumption. However it can be foreseen that such manipulations are likely to be legally challenged by consumers, who are likely to suspect that readings have been raised more than justified as a "correction". US Patent 5,659,300 to Dresselhuys et al discloses a meter arranged to transmit readings even when disposed in a pit. In one embodiment the meter is inductively connected to a transceiver external to the meter to communicate with an AMR system. In another embodiment the meter is operated by rechargeable batteries, while the batteries are recharged by a generator driven by the commodity flowing through the meter. The flow meter described by Keech in US Patent no. 6,256,590 B1 is claimed to improve accuracy by factoring in the non-linear dependence of field strength produced by coil current, which can be adjusted. Adjustment of coil current is intended to lower electricity consumption of the meter. A disadvantage of ' prior-art electronic fluid consumption meters is dependence on a magnet to generate a pulse and/or for transmitting rotational power. It is known that attempts have been made to steal water by manipulation of the water meter. Water meters dependent on magnetic devices can be stopped, or even reversed, by creation and manipulation of a strong magnetic field external to the meter. Many prior-art meters are thus targets for those wishing to deceive a supplier by underpayment for water, fuel or other metered fluids. Consideration must also be given to the drag produced by a magnet passing proximate to and generating a current in a stationary coil. Such drag will inevitably lead to reduced registry of actual fluid flows. The loss to the fluid supplier will be small but cumulative over the life of the meter. It is therefore one of the objects of the present invention to obviate the disadvantages of prior art fluid consumption meters and to provide a mechanism which does not impose external drag on revolution of the rotated impeller or turbine. It is a further object of the present invention to provide an optically readable meter, which can be interrogated by an AMR system. Yet a further object of the invention is to provide a long-life meter independent of external power supplies. The present invention achieves the above objects by providing a flow- through fluid consumption meter of the type having a chamber in which a rotatable part is revolved by fluid flowing through said chamber, said rotatable part being rigidly attached proximate to a first end of a shaft, characterized in that proximate to an opposite second end of said shaft there is rigidly attached an opaque rotor having a partially cut-away surface, which rotor revolves via said shaft with said fluid-driven rotatable part, said rotor being positioned between an optical transmitter-receiver pair which detects the blocking presence of said surface and the non-blocking cut-away area of said rotor surface, and said optical transmitter- receiver pair is electronically connected to an information processing unit arranged to receive and record data regarding the revolution of said rotor. In a preferred embodiment of the present invention there is provided a flow- through fluid consumption meter wherein at least two sets of said . transmitter- receiver pair are arranged in combination to detect both forward and reverse revolution of said rotor. In a further preferred embodiment of the present invention there is provided a flow-through fluid consumption meter type having a wet chamber in which a rotatable part is revolved by fluid flowing through said chamber, wherein said rotor and said opposite end of said shaft are surrounded by a transparent housing separating a dry chamber from said rotor, said dry chamber containing said at least one optical transmitter-receiver pair, said inner volume of said wet chamber being filled with fluid during use. In a further embodiment of the invention a flow-through fluid consumption meter has at least one optical transmitter-receiver pair and supporting electronic circuits operating on a current of less than 5 microamps. Further embodiments include a flow-through fluid consumption meter wherein said optical transmitter-receiver pair utilizes optical pulsing, and wherein said optical transmitter-receiver pair operates at infrared frequency. Yet further embodiments of the invention will be described hereinafter. It will thus be realized that the novel device of the present invention serves to prevent magnetic tampering with the meter either by the use of a long-term magnetic field to slow or stop registration or by short-term manipulation to reverse the direction of rotation. The long service-free life of the meter resulting from the elimination of gearing may be even more significant economically. In one of the invention embodiments the fluid filling the transparent cover of the rotor is retained without changeover to prevent flow-entrained debris from entering therein so as to ensure that an optically clear path is maintained between the light beam(s) and the rotor. The ability of the meter to respond to an AMR system could be the deciding factor in consideration of replacement of prior-art meters, and as with other electronic meters this is readily achieved by adding the appropriate prior-art components to the printed circuit board. The same board also carries a visually readable digital display allowing manual meter reading where necessary. Some of the diagrams provided show, for completeness, the whole or parts of the meter assembly, including features such as the body, end connections, glass cover, entry filter and the like. These items are of course well known and will not be described as no novelty is claimed therefore. The invention will now be described in connection with certain preferred embodiments with reference to the following illustrative figures so that it may be more fully understood. With specific reference now to the figures in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. In the drawings: FIG. 1 is a sectional elevational view of a preferred embodiment of the meter according to the invention; FIG. 2 is a perspective view of a preferred embodiment of the rotor; FIG. 3 is an upside down perspective view of a printed circuit board carrying two pairs of optical transmitter-receivers for reverse rotation deteqtion; FIG. 4 is a detail view of part of a meter driven by an impeller; FIG. 5 is a detail view of part of a meter where fluid is retained in the rotor chamber; FIG. 6 is a sectioned elevational view of an embodiment using a reflected light beam; and FIG. 7 is a perspective view of a preferred rotor suitable for the embodiment seen in FIG. 6. There is seen in FIG. 1 a flow-through fluid consumption meter 10. The meter is suitable for use with most transparent fluids, including fuels. The meter 10 shown is optimized for use as a water meter. The meter 10 is of the type having a chamber 12 in which a rotatable part 14 is revolved by fluid flowing through the chamber 12. The rotatable part 14 seen is arranged to drive a first, lower end of an upper shaft 16. An upper bearing 18 revolvably supports the upper shaft 16. Above the bearing 18 and proximate to an opposite upper second end of the upper shaft 16 there is rigidly attached an opaque rotor 20 having a partially cut-away surface 22. A preferred embodiment of the rotor will be seen in FIG. 2. The rotor 20 is free to revolve without contacting the walls of a transparent enclosure 23, and is driven, .being rigidly attached to the upper shaft 16, by the fluid- driven rotatable part 14. In the shown embodiment the rotatable part 14 is flexibly supported between the upper shaft 16 free to revolve in the upper bearing 18 and a lower shaft 24 free to revolve in a lower bearing 26. The rotor 20 is positioned between an optical transmitter 28 -receiver 30 pair, which detects the blocking presence of the rotor 20, and the non-blocking cut-away area 32 of the rotor surface. The optical transmitter-receiver pair 28, 30 is supported on a printed circuit board 33 disposed in a dry chamber 34 electronically connected by a flexible cable 36 to an information processing unit 38 arranged to receive and record data regarding the revolution of the rotor 20. The optical transmitter-receiver pair 28, 30 and supporting electronic circuits operate on a current of less than 5 microamperes. Power is supplied by a lithium cell 40 configured for low current/long life, application. Voltage is about 2 - 5, and expected life of the cell is 15 years, which exceeds the expected life of the meter. In the present embodiment pulsed current is applied to further reduce power consumption. A preferred operational mode is to arrange the optical transmitter-receiver pair 28, 30 to operate at infrared frequency. The information-processing unit 38 appears as a printed circuit board housed in the fluid consumption meter 10. The board includes a digital display 42 which can be manually read through the glass 44, and communication means, which is part of the information-processing unit 38, compatible with an AMR system. The meter does 10 not contain any magnet, and so it cannot be manipulated to give false low readings. With regard to the rest of the figures, similar reference numerals have been used to identify similar parts. Referring now to FIG, 2, there is seen a preferred embodiment of a rotor 46 for use in a flow-through fluid consumption meter of the type seen in FIG. 1. The rotor 46 has a cup-like shape, with about one half of its wall 48 cut away at 50. The rotor is attached to the upper shaft 16. The rotor 46 is balanced by thickening of the lower portion 52 at a location opposite the wall 48. When in operation the rotor 46 is disposed on the inside of the transparent cover 23, as seen in FIG.1 , The light transmitter (emitter) 28 sends a horizontal beam to the receiver (detector) 30 which is disposed in a central cavity of the transparent cover 23. The wall 48 forms an opaque section, which prevents light from the transmitter 28 reaching the detector 30, while the cut-away portion 50 allows the free passage of light. Determination of the number of revolutions made by the rotor 46 is easily handled by the information-processing unit 38 seen in FIG. 1 on the basis of the current pulse transmitted by the detector 30. FIG. 3 illustrates a detail of a flow-through fluid consumption meter, the detail being shown upside down for illustrative purposes. Two sets of the transmitter-receiver pairs 28, 30 are arranged, at about 90° to each other, and are positioned on a printed circuit board 54 so that when in operation the wall 48 of the cup-like rotor 46 seen in FIG. 2 passes between the detectors 30 and the light emitters 28. The arrangement detects whether the rotor 46 is revolving in the forward direction, or in the reverse direction, as could result by a consumer tampering with the meter. The information-processing unit 38 seen in FIG. 1 simply compares the time between a pulse received from detector 30A and the pulse received from detector 30B to determine direction of motion. Reverse direction rotation can be arranged to signal an alarm to an AMR system, or to trigger a release mechanism (not shown) for a red dye fluid held in a frangible container to stain components in the dry section of the meter. Seen in FIG. 4 is a detail of a flow-through fluid consumption meter 56 wherein the rotatable part is an impeller 58. The internal structure of the meter 56 directs water to one_. edge of the impeller 58. Referring now to FIG. 5, there is depicted a detail of a flow-through fluid consumption meter 60 of the type having a wet chamber 62 and a dry chamber 64. A rotatable part 66 is revolved by fluid flowing through the wet chamber 62. A rotor 68 and the upper opposite end of the shaft 70 are surrounded by a transparent housing 72 separating the dry chamber 64 from the rotor 68. The dry chamber 64 contains an optical transmitter-receiver pair 28, 30. The inner volume of the wet chamber 62 is filled with fluid during use. The fluid disposed in the transparent housing 72 containing the rotor 68 is maintained therein by the structure of the housing 72 preventing ingress of air thereto. Retaining the same fluid for long periods prevents the accumulation of sediment in the housing 72, which could cloud the walls thereof and make the meter 60 inoperative. A further embodiment of a flow-through fluid consumption meter 74 is seen in FIG. 6. The rotor comprises a disk 76, a sector 78 of which is opaque and non- reflective, or has an irregular surface to scatter an impinging light beam. The remaining sector 80 is transparent, and rotationally balances rotor. A sapphire bearing 81 stabilizes the top of the shaft 16. A stationary reflective surface 82 is disposed underneath the disk 76. A slanted optical transmitter 84 generates a light beam 86, which passes through a transparent cover 88 separating a wet and a dry section 90, 92 of the meter 74. The light beam 86 is dispersed if impinging on the opaque and non-reflective sector 78 and no signal is generated. When the beam impinges the transparent sector 80 of the rotor disk 76, the beam is bounced back from a reflective surface 94 and again passes through the transparent sector 80 to reach the receiver 96 and to generate a signal. This arrangement has the advantage that there is no need to position the receiver 96 in a cramped cavity over the center of the rotor. Turning now to FIG.7, there is seen a further embodiment of a rotor 98 useful for a meter of the type seen in FIG. 6. Instead of the transparent sector 80 about a half of the rotor disk is simply cut away, thus obviating the need for the light beam to pass twice through the rotor. The remaining portion 100 of the rotor disk is made of a thin lightweight material to prevent unbalancing forces from stressing the bearings 18, 81 seen in FIG. 6. It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes . thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

WHAT IS CLAIMED IS: 1. A flow-through fluid consumption meter of the type having a chamber in which a rotatable part is revolved by fluid flowing through said chamber, said rotatable part being rigidly attached proximate to a first end of a shaft, characterized in that proximate to an opposite second end of said shaft there is rigidly attached an opaque rotor having a partially cut-away surface, which rotor revolves via said shaft with said fluid-driven rotatable part, said rotor being positioned between an optical transmitter-receiver pair which detects the blocking presence of said surface and the non-blocking cut-away area of said rotor surface, and said optical transmitter- receiver pair is electronically connected to an information processing unit arranged to receive and record data regarding the revolution of said rotor.

2. A flow-through fluid consumption meter according to claim 1 , wherein said shaft is attached to an opaque cup-like rotor having a partially cut-away sidewall.

3. A flow-through fluid consumption meter according to claim 1 , wherein at least two sets of said transmitter-receiver pair are arranged in combination to detect both forward and reverse revolution of said rotor.

4. A flow-through fluid consumption meter according to claim 1 , wherein said rotatable part is an impeller.

5. A flow-through fluid consumption meter according to claim 1 , of the type having a wet chamber in which a rotatable part is revolved by fluid flowing through said chamber, wherein said rotor and said opposite end of said shaft are surrounded by a transparent housing separating a dry chamber from said rotor, said dry chamber containing said at least one optical transmitter-receiver pair, said inner volume of said wet chamber being filled with fluid during use.

6. A flow-through fluid consumption meter according to claim 1 , wherein said fluid is water.

7. A flow-through fluid-consumption meter according to claim 5, wherein fluid disposed in said transparent housing containing said rotor is maintained therein by the structure of said chamber preventing ingress of air thereto.

8. A flow-through fluid consumption meter according to claim 1 , wherein said at least one optical transmitter-receiver pair and supporting electronic circuits operate on a current of less than 5 microamperes.

9. A flow-through fluid consumption meter according to claim 1 , wherein said meter is magnet free.

10. A flow-through fluid consumption meter according to claim 1 , wherein said optical transmitter-receiver pair utilizes optical pulsing.

11. A flow-through fluid consumption meter according to claim 1 , wherein said optical transmitter-receiver pair operates at infrared frequency.

12. A flow-through fluid consumption meter according to claim 1 , wherein said information processing unit is housed in said fluid consumption meter.

13. A flow-through fluid consumption meter according to claim 1 , wherein said rotor comprises a disk, a sector of which is opaque and non-reflective, the remaining sector being transparent, a stationary reflective surface being disposed underneath said disk, the optical transmitter-receiver pair generating a light beam which passes through a transparent cover separating a wet and a dry section of said meter, said light beam being dispersed if impinging on said opaque and non- reflective sector, and impinging on and being reflected from said reflective surface if passing through said transparent sector before reaching said receiver.

14. A flow-through fluid consumption meter according to claim 13, wherein said transparent sector is cut away.