Model 718

Displacer Switch, Top Inserted, Four Point

The Delta Controls Model 718 Displacer Switch has two alarm points, four switching stations, and two displacers. A precise On/Off action occurs in the appropriate switch station when the liquid level surface passes the elevation of the related displacer element. The 718 is commonly used to provide a ‘High’ warning alarm, a ‘High-High’ shutdown action, a ‘Low’ warning alarm, and a ‘Low-Low’ shutdown action. The type service is found in processes where a heater must not be uncovered and the tank must not overflow. Another application is emptying a sump using three pumps. Each of the three top displacers starts a pump, the bottom displacer simultaneously stops all three pumps.

Options: The Model 718 Option D utilizes a fourpoint alarm, three switch stations, and an adjustable differential device. The lower switch station activates when the liquid level covers the L2 displacer and stays activated until the liquid level drops below the L1 displacer. The middle switch station activates when the liquid level covers the L3 displacer and stays activated until the liquid level drops below the L2 displacer. The upper switch station activates when the liquid level covers the L4 displacer and stays activated until the liquid level drops below the L3 displace.