Oil-on-Water Monitor, Model ODL- 12, Brand : TOA
This instrument detects oil films formed on a water surface using laser technology. It is installed between 0.3- 2m above the water surface and detects oil presence using a reflected laser beam. This monitor provides a low maintenance, non-contact solution to oil on water detection and can detect oil at below visible traces. The Model SODL-12 is a certified explosion-protected version, suitable for hazardous locations. The Model ODL-12 is suitable for non-hazardous locations.
Non-contact monitor using laser technology.
Can detect all types of film-forming oil with excellent sensitivity and fast response.
Small floor area requirement. Installation in manholes is possible.
Does not suffer from interference caused by substances floating on or suspended in the water. controller/ transmitter.
Field-proven — more than 500 units installed worldwide.
Service life of light source is 2 years.
Low maintenance requirements provide excellent cost of ownership advantages.
Principle of Operation
The reflectance of an oil film is greater than that of water. From this property the presence of oil can be detected by applying a light beam of constant intensity to the water surface and then measuring the intensity of the reflected light.
A laser tube emits light at a perpendicular angle to the water surface. The laser beam passes through a hole in the centre of a concave mirror and strikes the water surface. Since the water/ oil surface normally has ripples, the light is reflected in various directions from the incident point and strikes a large diameter ( 180mm) precision concave mirror which focuses the light onto a photodiode sensor located at the focal point. The focused light is then converted to an electrical signal. To remove the effect of interferences such as sunlight, the laser beam is pulsed using a chopper motor. The inner wall of this instrument is protected from irregular reflections and a solid, recessed glass plate at the bottom protects the concave mirror and sensor.
The pulsed photodiode output is sent to the peak detector via an AC amplifier and then to a peak hold circuit. When high peaks are continuously detected for a fixed period an alarm contact is activated. A 4-20mA output signal is coupled to model ZO-12 transmitter to drive a recorder ( optional) and alarm device ( optional) after further signal processing.