The analyser consists of a probe mounted in a measurement chamber and a transmitter unit with alarm and analogue output signals. The unit is mains powered.
The analyser consists of a probe mounted in a measurement chamber and a transmitter unit with alarm and analogue output signals. The unit is mains powered.
The analyser consists of a probe mounted in a measurement chamber and a transmitter unit with alarm and analogue output signals. The unit is mains powered.
The instrument is extremely easy to use and maintain – no special training being needed. The probe, a galvanic cell that generates a voltage in the presence of oxygen, never needs replacing, and is insensitive to wide changes in sample flow and temperature. The system exhibits excellent accuracy, long-term stability and response time.
Probe
This is manufactured almost entirely in stainless steel to give it the greatest stability and maximum protection from electrical interference. The sensor itself uses technology developed by OxyGuard. The result is a probe with short response time and excellent calibration stability. The very robust membrane can, if necessary, be changed in a few minutes.
Measurement Chamber
This is manufactured from clear acrylic plastic with stainless steel fittings. The clear plastic permits observation of the probe, an advantage when removing air bubbles after calibration. All the probe and measurement chamber materials can withstand high radiation levels, and can be used in nuclear power stations.
Transmitter
This consists of a high-quality industrial type instrument amplifier in an IP65 cabinet, with digital display, 4-20 mA analogue output (0-20 mA on request) that is galvanically isolated from the input, and a high level alarm with potential-free change-over contacts. A special circuit disenables the alarm during calibration. This is controlled by a timer, but can be reset manually.
Service and Maintenance
The probe is constructed to operate for many years without needing maintenance. The choice of anode, cathode and electrolyte is such that only the anode is consumed, and this has a nearly infinite calculated lifetime at 10 ppb! The electrolyte remains unaltered, and does not need changing as in conventional systems. Practical tests indicate that the probe, used at 10 ppb, will only need service if the membrane should be damaged, and this is very seldom since the membrane is very robust – it is 0.05 mm thick. If membrane replacement should be necessary the procedure is easy and can be performed by anyone, without prior training.
Type: Self polarising (galvanic) membrane covered amperometric cell
Sample temperature: 5°C to 60°C.
Sample flow: Depends on oxygen content and temperature – min. 50 ml/min,
max 2000 ml/min.
Sample pressure: From atmospheric to max. 6 bar.
Connections: 6 mm compression ring fittings.
Response Time: 90% in less than 25 sec.
From 1 minute in air (calibration) to 100 ppb in approximately 40 sec,
and to 10 ppb in less than 3 minutes (at constant temperature).
Transmitter
Measuring range: 0-100 ppb (or on request) (2-range version, 0-100 + 0-1000 ppb, available).
Output: 4-20 mA, isolated from input. 0-20 mA on request.
Indicator: LCD display, digit height 12 mm.
Alarm: 1 high alarm. Potential free change over switch, max. 200 VA.
Encapsulation: IP 65.
Operating temperature: -20°C to +60°C.
Practical System Performance
Accuracy: Error max. 0.5 ppb (or 3%).
Repeatability: Better than 0.5 ppb (or 2%).
Conformity: Linear.
Limit of Detection: 0.8 ppb.
Long term stability: 0.5 ppb (1 month).
Commissioning: Straightforward.
Probe renovation: Easy. (N.B. only necessary if the membrane is damaged)
N.B. The system has EMC (CE) approval
