DESCRIPTION
The height sensor has been developed for use in both
laboratory and industrial applications and is designed
to output average disc height, regardless of any disc
wobble or eccentricity.
The sensors are fully guarded to optimise system
output and are completely immune to both cable vibration
and temperature effects.
Deadweight pressure testers are widely used as primary
and working pressure standards throughout industry
where assurance of the accuracy of a pressure measurement
is a major consideration.
Deadweight testers comprise of a precision piston
and cylinder assembly, plus a set of calibrated masses.
They operate by applying a given force over a known
cross sectional area of a piston with a matched cylinder.
The cylinder is filled with the pressure medium, (Usually
oil or gas), and the seepage of the medium past the
piston provides the lubricant, keeping the piston
free from the cylinder wall and virtually friction
free. With this technology, it is possible to obtain
and measure pressures to a very high level of accuracy.
The height at which the piston floats within the
cylinder can be critical to the accuracy of the measurement,
as can the sink rate of the piston as the pressure
medium on which it is floating gradually seeps past
it.
For many pressure measurement operations, (such
as differential pressure calibrations, or when carrying
out a cross-float calibration of one Deadweight tester
against another), it is necessary to float two weight
sets simultaneously. The Future Technology dual channel
system, (with the right sensor selection), is the
ideal instrument to make the weight float height measurements
throughout the calibration process. Single channel
measurement systems are also available for monitoring
individual weight sets.
The sensors are generally set up to look at the bottom
of the lower weight on the carrier, and analogue outputs
from each channel displayed on a pair of suitably
scaled edge meters or input to a suitable data acquisition
system.
MEASUREMENT RANGE
Measurement range is a function of sensor size and
target geometry, and so dead weight sensors are usually
designed to meet individual customer requirements.
An installed measurement range of between 5mm and
50mm however, is representative of most applications.
The above working range is valid against metallic
surfaces, but may be reduced when applied to non-metallic
materials. Ranges quoted are for standard DW sensors
calibrated with FT1000-DX or FT2000-DX electronics.
