Case Study: Model CPH Proximity Switch Detects Floor Drain Backups

Murfreesboro, TN USA

We are pleased have provided the level sensor solution for this interesting application at a fast-food chicken restaurant.

Problem Summary

Grease traps are required in fast food restaurants and are located between the drain lines and the municipal sewer line, often inside the restaurant. Grease traps operate by slowing down the flow of water from the drains, allowing the water/grease to cool. When the fat/oil/grease cools it coagulates and floats to the top and heavier solids float to the bottom. The water is free to flow into the sewer system. Maintenance staff typically handles the job of cleaning the grease and heavy solids from the trap. If the cleaning and maintenance isn’t adequate the trap can clog and the drain water, with continuous flow from automatic ice makers draining, will backup into the restaurant. If the restaurant is closed for any length of time, like shopping mall restaurants are, this could become a messy problem.

Solution

The Model CPH is a line of capacitive proximity switches including both unshielded and shielded style switches, AC or DC powered. The unit featured in the below pictured application is a part number 47-1111-111 2-wire AC switch with normally open contact. The AC supply can be 20-255VAC and the switch can handle a maximum current load of 300mA. The application also included a relay and timer to sound an audible alarm bell to alert security or store personnel to an alarm condition.

The Model CPH is a compact and low cost sensor for use with clean fluids and dry, free-flowing powder and granular bulk solids. It is a very reliable device surpassing industry standards.