A new design of trace dissolved oxygen sensor has applications in power plant boiler feed-water pipework, offshore water injection, and semiconductor manufacture
A new design of trace dissolved oxygen sensor, the model 499A TrDO from Rosemount Analytical, is offered for the measurement of parts per billion levels of oxygen in high purity water.
Major applications will be where oxygen levels are deliberately scavenged from cooling or process water to prevent corrosion - for example - in power plant boiler feed-water pipework, in offshore oil drilling water injection applications, or in high purity semiconductor manufacture.
The Rosemount model 499A has an accuracy of +/-1ppb in the range 0-20ppb and a performance equivalent to the best sensors available, but with a much more competitive price.
The design specification has been significantly improved to provide a shorter sensor stabilisation period after installation at the parts per billion level. Typically, this is less than one hour following a membrane change or sensor recalibration and is a result of the Rosemount Analytical patented construction techniques and the use of a self-scavenging electrode.
Once in service, the operational response time for the 0-200ppb sensitivity range is less than 20 seconds.
As a result, end users experience quicker process turn-round times and overall plant performance improvements.
With the Rosemount 1055 liquid analyser electronics, the recalibration routine for the 499A sensor is simpler than ever, using a pcb-mounted barometric pressure sensor to feed readings automatically into the calibration routine.
Membrane replacement is fast and easy, requiring no special tools or fixtures, and electrolyte replenishment is carried out via a simple fill plug. A Variopol plug and socket connector is offered as an alternative to having an integral sensor cable connection.
The sensor itself has automatic temperature and salinity compensation for the dissolved oxygen measurement, and a flexible bladder to maintain equal pressure between sensor and sample stream.
Different versions of the 499 sensor are available from Rosemount Analytical for measurements of dissolved oxygen at the ppm level, and for steam sterilisable installations.
