Flow Measurement With Refracted Spread Spectrum Analysis (RSSA)
Pulsar have introduced two major innovations with the launch of Flow Pulse - firstly, of course, that the system is
non-invasive, and secondly the new way that the mass of flow data is analysed. Pulsar call it Refracted Spread
Spectrum Analysis (RSSA).
RSSA builds on Pulsar’s track record of excellence in acoustic digital signal processing. Pulsar’s non-contacting
ultrasonic level and open channel flow measurement equipment has revolutionised the way that process and
utility engineers view that technology, in large part down to the DATEM echo processing software on board.
Similarly, Sludge Finder brought Pulsar’s technical expertise to bear on the challenge of accurately and reliably
measuring sludge blanket interface levels
Flow Pulse is a major leap forward in flow
measurement - no need to break into a pipe, or to get
any civils involved, just clamp a small sensor to the
outside of a pipe and get reliable, repeatable flow
monitoring straight away.
Virtually no installation costs, no interruption to
service, clean and simple. Flow Pulse is simply fixed
in place by a band (tools required = one screwdriver).
A silicone coupling pad makes sure that the Flow
Pulse makes a good acoustic contact to the pipe.
Flow Pulse uses a novel spread spectrum analysis
technique never before used in flow monitoring. It
incorporates a radical new Digital Signal Processing
(DSP) approach that gives exceptional repeatability.
Flow Pulse produces a wide ultrasonic beam that is
refracted by the pipe wall, as well as reflected by
suspended particles in the flowing media.
Ultrasound is fired through the pipe wall at 90
degrees to the flow via a tangentially mounted high output
ceramic, then refracted at angles across the
axis of the flow and subsequently reflected from
bubbles, particles and vortices in all directions and at
a wide range of frequencies. The wide, refracted,
ultrasonic beam maximises the ultrasound energy
captured from flowing particles. These multiple
reflections are received back into the unit via a
second high performance ceramic.
The returned signal is analysed using Flow Pulse’s
Refracted Spread Spectrum Analysis (RSSA) digital
signal processing platform to derive flow information.
RSSA analyses and integrates the received signals
over a wide frequency range, then slices them for
real-time analysis and flow rate calculation.
The digital platform also offers robust performance in
the repeatability of measurement, as well as the
flexibility to adapt to application requirement. For
example, features such as damping and response
time can be easily customised to suit.
Flow Pulse operates in a flow range from as little as
0.3m/s through to 4m/s (1 - 13 ft/sec), with a
minimum particle size of 100µ and concentration of
200ppm or above (the equivalent of hard water).
Pipe material can be rigid plastic, stainless steel, mild
steel or cast iron. Corrugated pipe is not an issue,
and, as long as the silicone pad can fill in the
irregularities, light corrosion will also give a good
Flow Pulse provides repeatability of
around ±5% (up to 350mm/14 inch pipe dia).