It was developed to meet customer demand for a cost-effective, easy to operate instrument with a probe designed to cope with the high temperatures in the flue. Effective combustion control has growing importance for operators as it not only helps increase fuel efficiency but also ensures compliance with legislation on allowable emissions.
The XZR250 uses a zirconium-oxide sensor with a life span of up to seven years (depending on the fuel used) to maintenance to a minimum. A key benefit of the sensor is its fast response of less than fifteen seconds to changes in oxygen concentrations of 90% of the range. It is also accurate to <0.25% O2, allowing optimum combustion control.
The XZR250 is easy to install as it requires no specialised tools, it is also very light to handle and has a fast start-up routine. The probe can be inserted directly into boilers up to 700°C and uses the Pitot effect to ensure the sample gas is sufficiently cooled to protect the sensor from damage without the need for complex sample conditioning. As with any process instrument, regular calibration is necessary to ensure the accuracy of the measurements. The XZR250 can use air as a calibration gas, making calibration highly cost effective and simple to perform.
The robust sensor ensures maintenance is minimal, but when it does need replacing, this can be done with minimal process downtime. Michell has extended its popular sensor exchange programme for dew-point transmitters to customers of the XZR250. Under this scheme, operators order a new sensor block from Michell, which arrives ready to fit. Once fitted, the old sensor block can be returned to Michell in the same box and the customer receives a credit.
Typical applications for the XZR250 include oil, gas and biomass boilers.