Installation Manual

Accu-Wave Chapter 1 Introduction
TN Technologies 1-1
Chapter 1 Introduction
The Accu-Wave Model 1440 Radar Level Gauge uses a microwave signal to
continuously measure the level of the process material. The Accu-Wave provides better
performance than sonic measurement systems, particularly in hostile environments,
because the microwave signal is unaffected by mist, surface agitation, temperature
changes, or pressure changes. The standard menu-driven user interface, with built–in help
screens, the optional Windows-based Setup Software are designed to make the gauge
easy to set up and operate.
The Accu-Wave transmits a microwave signal that is reflected from the surface of the
process material. The reflected signal or echo is received by the Accu-Wave. The Digital
Signal Processing (DSP) software detects the echo and computes the distance to the
liquid or solid material in the tank. The Accu-Wave firmware uses the distance
measurement to calculate level, volume, and other user-selected measurements.
Description
The Accu-Wave Radar Level gauge consists of an integrated sensor and transmitter with
the microwave sensor and transmitter circuitry combined on a single electronics board.
The microwave signal is launched from the bottom of the board via a cup/probe assembly
into the antenna. The antenna serves to focus the transmitted signal as well as to receive
the reflected echo. Currently, the Accu-Wave is available with dielectric rod antennas.
Horn antennas will be available as a future option.
Antennas
The standard antenna configuration for the Accu-Wave gauge consists of a dielectric-
filled, 1 inch O.D. stainless steel waveguide with a dielectric rod antenna. The dielectric
rod antenna is available in either polypropylene or Teflon (PTFE). The stainless steel (SS
316) waveguide material is swaged (crimped) over the dielectric-fill material. The swage
serves both as a process seal as well as a pressure seal. The PTFE antenna design also
uses O-rings to ensure the integrity of the process seal. Viton and Kalrez O-rings are
available.
Horn antennas, with diameters ranging from 2 to 8 in., will be available as a future
option.
Mounting Configurations
The dielectric rod antennas are fitted with either a 1-inch NPT threaded bushing, welded
to the waveguide, or with a welded flange. The available flanges sizes are 150 lb. or 300
lb., with diameters of 2, 3, 4, or 6 inches. Waveguides are provided in lengths of 6, 9, 12,
or 15 inches lengths, where the length refers to the portion of the waveguide that extends
below the bushing or the flange. For optimum performance, the end of the waveguide
should extend to the bottom of the tank nozzle or below.
Level measurements can be made even when the process material level is in contact with
the dielectric antenna to within ~3.5 inches of the bottom of the steel waveguide.