A bespoke pump maker is using ultrasound to model drive torque and thus
contain development costs to within predictable limits
Charles Austen Pumps manufactures products that are designed to meet
specific customer requirements, requirements that generally cannot be
satisfied by off-the-shelf pumps. Much of its work comes down to
optimising drive dynamics to produce the desired characteristics, be it a
smooth flow in a critical medical situation, ultra low noise for pumps in
home and office installations, or the guaranteed extra long life of pumps
in inaccessible locations.
The cyclic nature typical of many pump operations tends to induce
torsional oscillations in the drive shaft, which can have a significant
adverse effect on performance if unchecked, and this is where much of
Charles Austen Pumps' development effort is focussed, as technical
Manager Brian Glover explains:
We have recently built a new test station based on Torqsense, Sensor
Technology's surface acoustic wave (SAW) sensor, and it is proving it's
worth time and time again. Many years ago we used a simple torque arm and
scales when developing a prototype, then we moved on to slip ring
technologies, which were expensive and difficult to use because they
induced a frictional load all of their own. The state of the SAW art has
now moved to a higher plane, so last year we decided to tap into Sensor
Technology's expertise and develop a new rig. They supplied us with a
Torqsense unit and helped with designing and building the rig.
SAW provides non-contact monitoring of instantaneous rotary torque,
allowing accurate modelling of load changes. In essence, a Torqsense is a
frequency dependent strain gauge operating at ultrasound frequencies. It
consists of a transducer mounted on the shaft, which monitors variations
in the resonant frequency of a drive shaft as the torsional load varies,
transmitting a radio frequency signal to an adjacent pick up.
Torqsense embraces all the advantages of SAW technology, including a
broader signal bandwidth than other analogue based technologies and
absence of electronic interference. As Charles Austen Pumps found, it
often also proves far lower cost, simpler to use, is more reliable and
has a wider operating range compared with contacting types. Mr Glover
sums up:
Our reputation is based entirely on the quality of our engineering, and
our business on the ability to forecast development costs accurately for
each job. Sensor Technology has helped us build a new facility that makes
our drive engineering accurate, predictable and reliable, or put another
way we are moving from a black art to an exact science!
Sensor Technology
Charles Austen Pumps