Eutech Instruments Dissolved Oxygen Probe USER MANUAL 1
1 1.1 DESCRIPTION The Eutech Probe The probe is a galvanic measuring element, which produces a millivolt output proportional to the oxygen present in the medium it is placed in. It consists of an upper part with cathode, anode and cable, and a cap with membrane and electrolyte. Oxygen diffuses through the membrane onto the cathode, where it reacts chemically and then combines with the anode. This chemical process develops an electrical current, which flows through a built in resistor.
2 INSTALLATION The Eutech probe is easy to install. It should be placed where there is some movement in the water-1 cm/sec is enough at 7 mg/1 and 13 C. Ensure that the probe does not strike against the tank wall, and do not mount it directly above diffusers etc. Each probe is connected using ordinary 2-core cable, and it is fitted with 3 meters of PU cable unless otherwise specified. The brown wire is positive, the blue negative. 3 3.
3.2 Maintenance The probe’s membrane must be kept free from deposits. All surfaces in a biologically active system will be covered by a film composed mostly of bacteria. This bacteria film acts as a diffusion barrier for the oxygen that must diffuse through the membrane. The membrane must, therefore, be cleaned at regular intervals, the frequency depending on the actual condition. Cleaning can be performed with a cloth or soft paper.
4 4.1 SERVICE PROCEDURE DO Probe membrane replacement and probe renovation All probe types need membrane replacement if the membrane is damaged. Probes used in aquaculture (type 1) may need renovation if, after some years use, it is not possible to calibrate up to the correct value. Other probes should NOT need renovation unless subject to extreme conditions. Eutech probes do NOT need regular renovation. 1) Start by cleaning the outer of the probe, then unscrew the cap.
A new membrane can easily be fitted to the cap – see the drawing overleaf. The membrane must be flat – if it wrinkles remove it and try again with a new one. It is important that all parts are clean and dry. Neither O-ring nor membrane can be used more than once. 4.2 Spare Parts The Eutech probe is manufactured from tried and tested parts of the highest quality, so the need for spare parts is minimal.
4.3 Probe Maintenance - Drawing 5. SPECIFICATIONS Dimensions: 58 mm dia x 59mm. 3 m cable standard. Weight: 350 g with standard cable. Measurement Principle: Self polarizing, self temperature compensating galvanic cell. Output: approximately 25 mV in normal air Operating Conditions: 0 to 40° C, pressure to 10 bar or more.
Connection of Eutech DO probe with built-in Pt 100 BROWN - DO probe + BLUE - DO probe - YELLOW BLACK BEIGE 7 Pt 100 sensor
