A recent trend in level measurement for lift station wet wells is radar technology. In the past, radar transmitters were considered too
expensive for use in wet wells but recent developments
in electronics have allowed for new offerings in the sub-
Radar transmitters offer a number of advantages over
traditional wet well level technologies. First, like the ultrasonic instrument, radar is a non-contact technology using the time-of-fight measurement principle. With radar,
an electromagnetic pulse is directed to the surface of the
material being measured. The energy is refected by the
dielectric property of the water. Similar to ultrasonic, the
time taken to reach the water surface and the refection to
return are measured, providing a distance to the surface of
the water, which is then used to calculate the level.
Along with the advantages of non-contact measurement, the transmission of electromagnetic energy is not
affected by vapors or steam in the air space above the
water, which is a decided advantage over ultrasonic level
New radar antenna designs provide wetted parts of
all Tefon with a concave surface. These concave antennas are designed to shed condensation buildup on
the antenna face, preventing attenuation of the electromagnetic signal. In sewage wet well applications,
the Tefon helps to prevent coatings from adhering to
the antenna when water splashes solids.
MAPPING IT OUT
One of the great advances in new radar units is the simplicity of commissioning and mapping. Accessing the setup program can be done via
Bluetooth® and executed on a smart phone or tablet.
This is a great advantage over older units that required
commissioning through a push-button HMI interface or
opening the housing and connecting a cable to a laptop
with a modem.
In many cases the radar transmitter may be located in
an installation that is diffcult to access. This is particularly
true of water and sewage wet wells where the radar may
be inside a concrete vault. Trying to reach these units for
access to the HMI or to connect a cable to a modem may
require a confned-space permit. With Bluetooth, in most
cases it is a simple matter of opening the manway.
New radar technology offers sophisticated mapping
programs that allow the transmitter to ignore internal
obstructions such as ladders, pump columns, cables and
baffes. While these mapping programs are sophisticated, they are much easier to implement than previous
mapping programs from even a few years ago.
There are a number of ways to measure the water
level in lift station wet wells. Selecting the technology
able to provide the most reliable level measurement
with the least maintenance should be the goal. While
traditional technologies such as submersible hydrostatic and ultrasonic instruments can provide a reliable
measurement, the new lower-cost radar transmitters
now available in the market should be considered for
these applications. The advantages gained in performance and reliability along with the ease of commissioning are signifcant. WW
Bill Sholette is the level product business manager for Endress+Hauser. Learn
more at www.yourlevelexperts.com/bluetooth-boundless.
New Trends in Low-Cost Radar Provide
Increased Performance, Reliability
BY BILL SHOLETTE
Presented by Endress+Hauser Advertisement
With radar units, access to the setup program can be made
via Bluetooth® and executed on a smart phone or tablet.
In the past, radar transmitters were considered
too expensive for use in wet wells but recent
developments in electronics have allowed for
new offerings in the sub-$1,000 range.