Case study: water meter technology
Background
Solid-state electronic registers for residential mechanical water meters are beginning to appear in territories where AMR systems are being deployed. These registers allow easier integration with AMR infrastructure, and more complex billing and leak detection functions. However, they are still reliant on the underlying technology of the traditional mechanical meter, with its associated limitations:
- Poor tolerance of particulates
- Easily damaged when air gets into the pipe
- Under-registration at low flow rates
- Increasing inaccuracy as the meter wears out
- Limited self diagnosis of metrology faults
These limitations translate into increased cost of ownership and lost revenue for the utility, which can be equivalent to many times the original cost of the meter over a 20-year period.
The opportunity
By integrating an appropriate solid-state flow sensor with the register electronics, Sentec believes it is possible to overcome the limitations of a mechanical sensor. The aim is to retain the benefits of an electronic register, and to meet a cost point that is comparable with the hybrid mechanical/electronic design.
An additional benefit of an entirely solid-state meter is the ability to deliver future value added services over a long lifetime.
Our approach
The utility industry has traditionally been a conservative one. For new products to be accepted, they must generally offer a better performance/price ratio, in a similar mechanical envelope. Sentec has created a radical new approach to an electromagnetic flow (magflow) sensor that breaks through the barriers of conventional magflow design - cost and power consumption.
Our innovation has allowed us to create a sensor that can bring the proven performance of industrial magflow meters to a mass-market residential battery powered product.
Magflow sensors are inherently insensitive to flow disturbances, pressure, temperature and vibration effects. These characteristics are ideally suited to the poorly-controlled environment where water meters are typically installed. The sensors require no complex correction curves or multi-point calibration processes, because they are intrinsically linear.
Sentec's innovation allows an order of magnitude improvement in performance (turndown vs. battery life) over existing designs. This is achieved by using novel electrodes in combination with a low-cost low-power magnetic field generation system that produces a continuous interrogation field.
Sentec's technology can deliver a number of attractive features for water meter manufacturers and their customers:
- Comparable cost to AMR-equipped mechanical meter
- Continuous measurement - doesn't "turn off" to save power
- Inherently reliable - no mechanism to jam
- Maintains accuracy over lifetime - no moving parts to wear
- Better accuracy at low flow rates - no friction or losses
- Highly tolerant to particulates - clear, straight-through path
- Accurate measurement of reverse flow - unlike fluidic oscillator
In addtion, combined electronics and sensor gives opportunity for:
- providing water quality information
- self diagnosis and condition monitoring
- providing anti-tamper information
- adding advanced billing tariffs such as time of use.
Sentec is now in detailed discussions about licensing opportunities with a number of leading water meter manufacturers.
