Flowmeter meets landing gear test rig needs

A high performance flowmeter was found capable of meeting the demands of a landing gear test rig whilst being easily installed on pipework next to existing instrumentation.

A high performance flowmeter was found capable of meeting the demands of a landing gear test rig whilst being easily installed on pipework next to existing instrumentation.

When one of the world's foremost aircraft manufacturers required a specialised flow measurement solution for one of its landing gear test rigs, they chose Katronic Technologies to provide it for them.

The problem faced by Airbus UK at Filton, Bristol, was to find a high performance flowmeter capable of meeting the demands of their application whilst being easily installed on pipework in close proximity to existing instrumentation.

In order to be suitable, the flowmeter had to be capable of measuring flow in pipework ranging from 3/8in (9.5mm) to 1.1/2in (38mm), in pipe materials including steel, aluminium and titanium.

It was essential for the flowmeter to perform well even with greatly varying process conditions such as a pressure range of 5-350 bar g.

Furthermore, all readings had to be taken in a very short period of time as the maximum measurement window was only two minutes.

The solution was supplied in the form of the new KATflow 140 ultrasonic flowmeter from Katronic Technologies.

The flowmeter takes measurements completely non-invasively and is thus independent of the varying process conditions.

The Airbus hydraulic rigs at Filton support the design verification testing of all the Landing Gear systems employed across their Single Aisle and Long Range Aircraft.

The A380 Landing Gear Test building houses the complete landing gear system, and all associated sub-systems, aircraft hardware and avionics.

Prior to this current application the KATflow units had already been successfully deployed on the Airbus A340-600 Landing Gear Test Rig.

The clamp-on flowmeters were originally installed as a replacement for traditional inline turbine positive displacement flowmeters.

Testing done with these instruments on previous rigs had shown the turbine meters to be costly to maintain and unable to cope with the dynamic flow condition of the liquid.

As Dave McDonald, Airbus Test Controller for A380 Landing Gear Systems explains: "Experience has taught us that over time, turbines suffer in extreme, dynamic, high-pressure environments." By using a non-invasive clamp-on flowmeter, long-term system integrity is maintained without compromising the desired level of flow monitoring accuracy.

As well as improving on the performance of the turbine flowmeters, McDonald also highlights other practical advantages of the non-invasive flowmeter.

"The use of the KATflow 140 also led to greater measurement flexibility, zero down-time on the test rig and no requirement for regular recalibration." As the clamp-on sensors are not subjected to the same internal flow conditions as the turbine meters there is no risk of deteriorating performance.

Furthermore, in order to make commissioning of the transmitter more straightforward for the Airbus engineers, the flowmeter was supplied in a practical 19in housing suitable for insertion in to existing instrumentation panels.

Initial testing of the KATflow sensors at the Filton test facility allowed Katronic's Development Team to refine the measurement technique to meet the customer's challenging operating environment.

As McDonald further explains: "We have been very impressed with the portability, versatility and durability of the sensing equipment".

"When you add these qualities to the very fast signal process time of 70ms, Katronic supplies an impressive flow measurement package." By delivering a very fast measurement rate it made it possible for the engineers to gather a large amount of measured data in the small available timeframe.

The ultrasonic flowmeters are now part of the Airbus test routine and Katronic hopes to continue to play a part in the development of new aircraft systems in the future.

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