Q46D Dissolved Oxygen Monitor

Improve Performance & Reduce Maintenance Costs!

ATI’s Model Q46D Dissolved Oxygen Monitor is designed to provide reliable oxygen measurement and help reduce operating costs. Two types of sensing technologies are available for use with the Q46D system: Membraned Electrochemical and Optical (fluorescence). Both sensors will provide reliable long-term performance with minimal maintenance. No hardware modifications are required to change from one sensor type to the other. The monitor can be configured for AC or DC power supplies, and a portable battery-powered unit is available to meet a variety of monitoring needs. When process conditions require frequent sensor cleaning, our unique Q-Blast Auto-Cleaner can be used to keep the system operating nearly maintenance free. This time-proven system has been instrumental in providing years of worry free operation. ATI’s Q-Blast option provides the ideal answer for automatic Dissolved Oxygen sensor cleaning.  Employing a unique “air-blast” cleaning method, sensors can be cleaned as often as necessary without operator attention.  Pulses of pressurized air delivered through a nozzle at the tip of the sensor remove accumulated solids from critical sensing surfaces, resulting in accurate and reliable measurements. The Q-Blast Auto-Clean assembly is housed in a NEMA 4X enclosure suitable for indoor or outdoor use.  The system includes an integral compressor and air-pulse control components, with a power supply for the entire air supply system incorporated into the design.  A simple connection to the Q46D monitor provides the sequencing for the system and allows the operator to select cleaning frequencies as often as once every hour to as little as once every 999 hours.  To ensure performance in extreme cold conditions, a thermostatically controlled heater is included in the assembly, allowing operation down to -40°C.

Optical Sensor Reduces Maintenance!

ATI DISSOLVED OXYGEN SENSOR TYPES

OPTICAL SENSOR

The optical DO sensor operates on a light-based principle called “fluorescence” which is a type of luminescence. Certain chemical compounds will absorb one type of light energy, and then emit a different type of light energy. This light emission is called luminescence. The active portion of the sensor has a metal-based compound embedded in a structural matrix. A light source inside the sensor illuminates this compound which absorbs light at a specific wavelength. The compound then emits light at a different wavelength which is picked up by a photo detector within the sensor. As oxygen diffuses into the active sensor material it interacts with the light absorbing compound and interferes with the emission reaction. This interaction, called quenching, causes the light absorbing material to release energy in a form other than light. The degree of quenching is proportional to the concentration of dissolved oxygen. The quenching reaction is reversible, which allows this sensor to measure increasing and decreasing concentrations of oxygen.

 

Optical sensors do not have internal electrolyte, so maintenance of this type of sensor is limited to changing the optical element. Over time, the element will lose the ability to absorb light due to a process called “bleaching”. With some sensors, this process is greatly accelerated when it is exposed to direct sunlight, and will cause irreversible damage to the sensor element.