Model 718A

SKU: 718A

Displacer Switch, Top Inserted, Four Point

Operation: The weight of a displacer is supported by a spring. Variations in liquid level cause the displacer to move up and down. Switching action occurs as the level passes each displacer.

Uses: High and/or low alarm; single and multiple pump control

Insertion and Switching band: up to 50 feet maximum

Switch action: From 1 to 4 points of alarm and/or on-off pump control

Specific Gravity: form 0.25 to 2.4 SGU

Temperature: from –20 to 500°F

Pressure: from –15 to 2200 PSIG

Process Connection: 3″ to 4″ NPT threaded; 3″ to 12″ flanged up to 1500# rating; ASA, DIN, or JIS style


The Delta Controls Model 718A uses the same mechanism and body as the Model 717A. The difference is that it is equipped with an additional displacer and switch station. 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 Model 718A 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.

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