Clearance Sale: NOS (New Old Stock) Brand New Never Used. 

Compare to new models with a price of $60.68 each. This is a good deal. 

Free Shipping!!

Dwyer Instruments: OLS-11 Optical Level Switch Polysulfone

Compact and Rugged this optical level switch provides rapid response while employing no moving parts for stable process control. The bright red and green LED's indicate the presence or absence of liquid for true, local indication. Compact Switch can be easily mounted horizontally or vertically. The model OLS Optical Level Switch maintains predetermined levels in liquid holding tanks, sumps, air conditioning systems, hydraulic reservoirs, pharmaceutical and beverage systems.

Principle of Operation

The Optical Level Switch employs an infrared LED which transmits infrared light. This light is sent through a prism and reflected back to a photo-transistor utilizing two 90 degree light reflections. with the prism surrounded by gas, the light source is cast back to the photo-transistor. When a translucent liquid is introduced to the prism at or above the point where the light source makes contact with the prism, the light is reflected into the liquid, not allowing the photo-transistor to energize.