Domestic gas meter test system for series testing and calibration

Series testing at the meter manufacturer with the domestic gas meter test system

At the end of an assembly line for diaphragm gas meters, the domestic gas meter test system determines how many finished meters go to dispatch per shift. Because testing sets the pace of the line, we design these systems as production machines for multi-shift operation. Meter manufacturers based in Europe test their domestic gas meters almost without exception on inotech systems.

An automatically clamped in-line test bench holds up to 24 meters and saves clamping each meter under test by hand. We derive the number of positions on a domestic gas meter test system from your annual volume and from how often the line changes over between meter variants. The standard test medium is ambient air. The measuring range starts below 10 l/h and extends to 10 m³/h. A test system for domestic gas meters thus covers the lower partial-load range as well as the maximum flow of a domestic meter.

We develop the mechanical design, PLC program and test software ourselves. Assembly and final testing of every domestic gas meter test system take place in our own production. We guarantee the supply of spare parts for ten years. For water and heat meters coming off the line in the same plant, we also build the right meter test system.

Nozzles or reference meters as the standard for domestic gas meters?

Both principles have their place, just not in the same part of the measuring range. Reference meters such as rotary piston or turbine gas meters play to their strengths at larger flow rates, for which we build a dedicated commercial gas meter test system. For domestic meters, two reasons speak for critically operated nozzles.

First, a nozzle has no moving parts. Neither rotor nor bearings can wear out over the years. Second, the desired test point is reached as soon as the matching nozzle is switched in, without a valve having to readjust. That is why a nozzle test bench tests gas meters at very low flow just as reproducibly as at maximum load.

What does this mean in operation? Your domestic gas meter test system loses no time between test points. This is noticeable in the cycle time, especially with many test points per meter. Nozzles, pressure and temperature sensors can themselves be calibrated, so traceability remains verifiable over the entire service life. On request, we have a new domestic gas meter test system additionally certified by a recognised laboratory before delivery.

Encrypted smart meter communication in the domestic gas meter test system

A smart meter is not judged by its measuring element alone. Before delivery, data exchange via the interface and, if present, the integrated shut-off valve are also part of the test. For this, the domestic gas meter test system addresses the meter under test via its own interface modules and reads out the meter reading and measured values during the test run.

Many new gas meters only release their data in encrypted form. Our domestic gas meter test system handles this secured communication, so such meters are also tested in the regular series process. The encoder function of a register can likewise be included in the test sequence, i.e. the electronic transfer of the mechanical meter reading to the evaluation.

The protocols of common smart meters are already stored in the test software. If your next meter type comes with its own protocol, we write the interface for it.

Calibration and communication test thus run at one test position, without the meter changing stations. For temperature-compensated meters and pulse outputs, we extend the domestic gas meter calibration system with suitable additional equipment. If you operate older systems, we retrofit the communication modules there.

Re-verification and sampling tests for utilities and testing bodies

For a utility, the focus is not on the new meter but on the installed base in the network. With a sampling inspection you demonstrate that a meter lot still measures within the permissible error limits. If the result is positive, the verification period is extended and replacement of the entire lot is postponed by several years.

Legal verification itself remains the task of the state-recognised bodies. We supply the domestic gas meter test system approved for legal metrology on which your re-verifications take place, designed in accordance with OIML, the Measuring Instruments Directive MID and the requirements of the PTB. The network contains meters from different manufacturers and years of manufacture. A fast type change at the test position counts for more here than the last second of cycle time. Before testing, used meters can be purged of residual gas in our purging system. It holds up to eight meters of sizes G1 to G65 at the same time.

Any domestic gas meter calibration is only reliable if the system’s own standards are traceable. Our calibration laboratory for gas meters is available for periodic recalibration. Its DAkkS accreditation applies to the published scope and follows DIN EN ISO/IEC 17025:2018.

Camera-based register recognition on the diaphragm gas meter test system

Conventionally, an optical sensor only scans the reflective spot on the last drum of the register. Our CAMINO camera system instead reads every single digit on this drum. The check measurement therefore starts earlier. When you switch to a different meter type, the camera finds the relevant features itself, instead of someone realigning sensors. On a diaphragm gas meter test system with many test positions, this time saving adds up shift after shift to significantly more tested meters. You do not have to do without the mechanical check via the pulse disc.

Would you like to integrate CAMINO into a new domestic gas meter test system or retrofit an existing line? Tell us the meter types, annual volume and number of test positions. You will receive a free quotation that lists the clamping system, communication modules and camera system separately, so that you can weigh the components against each other. Coordination through to commissioning at your plant is then handled by a project manager who is responsible for your domestic gas meter test system from the order onwards.