Quantum gas meter

Cambridge Consultants has developed an inexpensive gas meter called Q-Smart for Siemens Energy Services who run the UK’s Quantum gas pre-payment scheme.

The rental costs of smartcard-based gas meters used to manage the pre-payment process represent over half of the total ‘cost to serve’ the consumer, and any economies that can be made have a big impact on the bottom line.

‘A lot of the original pre-payment meters are due for replacement in the next few years, and we commissioned this new meter design to allow the Quantum scheme to run more efficiently and cost-effectively,’ said Matt Hamblin of Siemens Energy Services.

‘We have eliminated parts, re-worked functions so that they can be performed by lower-cost components or software, and generally optimised the meter for high volume manufacture,’ said Cambridge Consultants’ Martin Cooper, who led the product development. 

Q-Smart reduces meter construction costs by around a third. Much of the cost reduction stems from the design of the meter’s electronic control circuitry, which is simpler than that used in existing Quantum meters. The circuitry has fewer components and requires only one major IC - a standard 16-bit microcontroller that mounts on one low-cost single-sided PCB, replacing two used in other meters.

A lot of thought has also been applied to minimising power consumption. The control software ensures that the control circuitry ‘sleeps’ for the vast majority of time. In conjunction with other power management techniques, this allows the new meter to operate for its entire life from a single cell - rather than two.

This circuitry manages the gas valve and flow meter - which is a conventional and low-cost bellows design - plus a man-machine interface with an LCD, pushbutton, and smartcard reader. The meter design still meets the requirements of the ATEX explosive atmospheres standard, and includes powerful fail-safe features to protect the consumer.

The meter makes further contributions to cost reduction by eliminating common causes of service visits.  Its low power consumption means that the battery life exceeds the target life of the meter itself - in excess of 10 years - eliminating battery changes. Simpler mechanical construction has also eradicated some of the meter ‘tamper’ faults that currently close the valve and necessitate a service visit.

New facilities incorporated in the software eliminate further common causes of visits, such as a change in tenancy or gas supplier. Other new features include extensions in the command set that allow the Quantum processing centre to send messages to individual meters via the consumer’s smartcard.  Among these is a ‘suspended disconnect’ facility that allows the energy supplier to postpone valve closure during holiday periods when it might be difficult to recharge the smartcard, or overnight when a service visit would be more expensive.