Prevent MIC in tanks and sumps *before* it happens
• New Technology
• Install at the top of 4" riser pipe from diesel USTs.
• Also installs inside gasoline & diesel dispensers and sumps.
• ASTs and on top of floating roof tanks.
• Advanced warning against aggressive MIC caused by acidic conditions.
• Does not detect common non-aggressive light corrosion caused by moisture.
• Compatible with all Adsistor based UST monitoring systems.
• Can be checked with a hand-held ohm meter.
• Detects corrosive conditions before corrosion appears on mild steel coupons in side-by-side testing.
• Detects corrosive conditions both in condensing atmospheres and dry atmospheres (RH < 50%).
• Not affected by continuous exposure to neutral (pH 7) condensing humidity.
• Not affected by continuous exposure to saturated diesel vapor or intermittent exposure to gasoline vapor.
How it Works
A substantial improvement in resistive corrosion probe technology is achieved by breaking up a single corrosion probe into thousands of individual micro-probes which are electrically connected end to end. By this arrangement corrosion on any single micro-probe acts in accordance with the series law of resistance instead of the parallel law of resistance. A dramatic amplification of response to corrosion is thereby achieved which gives an early warning to corrosive conditions long before significant corrosion occurs.
The Adsistor MIC sensor utilizes micro-particles of electrically conductive ferrous material which have been fixed in place by means of flexible anchors. These particles are shaped and spaced such that they are not normally in contact with each other. When a magnetic field is applied across all the particles the flexible anchors allow the particles to align with the applied field so that the particles are now in contact with their neighbor particles. An electrical path is thereby established through the sensor. Should corrosion occur at any particle junction, the electrical path is broken.
Microbial Influenced Corrosion vs. Common Corrosion
The Adsistor MIC Sensor only detects the conditions that cause microbial influenced corrosion (MIC). It does not detect common surface area corrosion or the conditions that cause common corrosion.
Microbial influenced corrosion is caused by the activity of bacteria and their byproducts. Formic and acetic acid are byproducts of bacterial metabolism and are responsible for the aggressive type of corrosion found in USTs and ASTs storing low sulfur fuel. Water is usually present also. MIC continues to attack mild steel until it is completely consumed.
Common surface area corrosion is caused by more or less neutral pH water coming into contact with mild steel in the presence of air. Common surface area corrosion forms a relatively thin surface layer of oxidation which usually protects the underlying steel from further corrosion.
Mild Steel under MIC attack in wet conditions (condensing humidity) 100x. Detected by MIC Sensor.
Mild Steel under MIC attack in dry conditions (RH<50%) 100x. Detected by MIC Sensor.
Mild Steel wetted by neutral water (pH near 7) in air, 100x. Not detected by MIC Sensor.
MIC Sensor Electrical Characteristics:
• Operational temperature range 0°C to 60°C
• Base resistance range 5 ohms to 100 ohms
• Maximum resistance 20 Meg-ohms
• Set alarm point at 10K-ohms when MIC sensor is placed in saturated diesel vapor. The alarm point may be set at a lower resistance value if greater sensitivity to corrosion is desired. Summer diesel deliveries may cause the MIC sensor resistance to temporarily exceed lower trip point values until the warm diesel cools--if the sensor remains in alarm for more than 72 hours then corrosion is indicated. A corrosion alarm can be verified by visually inspecting the sensor surface which will appear rusty.
• Response time. Like corrosion itself, many factors affect the rate at which the sensor resistance increases: temperature, concentration of acid in the fuel, relative humidity & amount of condensation in the ullage space. Sensors typically exceeded 10K-ohms within a week in our 25 L test chamber containing 400 ml vinegar (20 ml of acetic acid) in 4 L of diesel fuel, 100% RH @ 10C. See product video.
• If the sensor's resistance has exceeded 10K-ohms due to corrosion then it should be replaced. Replacement is not necessary if the resistance increase is due to temporary exposure to gasoline vapor or warm diesel vapor.
• Maximum DC/AC current 2mA
• Sensor leads are not polarized, just like a typical passive resistor