Model 770

SKU: 770A

Displacer Switch, External Cage, Vertical, Multipoint, Optional Wide Differential

  • Operation: A float with a long stroke action moves up and down as the liquid level varies. Switching occurs at up to four separate points.
  • Switching Stations: 1 to 4; alarm and/or differential
  • Differential: up to 72″
  • Specific Gravity: 0.4 to 2.4
  • Temperature: -20 to 750°F
  • Pressure: -15 to 2200 PSIG
  • Process Connection: Same as type 760
 

Model 770 Product Diagram - Delta Controls Corporation

The Delta Controls Model 770 provides switching alarm contacts at up to four elevations of a varying liquid level. The unit has its float mounted outside the process vessel in a cage. The external cage design is utilized to minimize process turbulence effects and in order that the level control may be valved off from the process vessel and depressurized for maintenance without disturbing the operation of the process. The output of the control consists of switching action as the liquid level varies. Up to four switch stations are operated. Action occurs as the attractor arrives at each switching station.

The switch stations are on the outside of the barrier tube which isolates them from the process liquid. Each is equipped with a magnet whose lines of force pass through the nonmagnetic barrier tube. The magnet is pulled in against the outside of the tube when the attractor is lifted into the magnetic field inside the tube.

The liquid level rises and the float lifts the attractor in front of each switch station magnet. The magnet pulls in and its output switch is actuated. Each magnet pulls in sequentially as the liquid level continues to rise, and stays in as long as the liquid level is above that point. Decreasing liquid level moves the float/rod/collars/attractor downward. Each output switch remains actuated until the attractor is pulled out of its magnetic field; it then deactuates.

The Delta Controls Model 770 should be mounted vertically near the process vessel containing the liquid level to be monitored. It should be positioned so that the desired switching points are located between the upper and lower process connections on the element body. Long lines connecting the process vessel to the element chamber should be avoided; but when necessary, they should be sloped 1″ per foot towards the process vessel to limit sedimentation buildup.

The Delta Controls Model 770A provides switching alarm contacts at four elevations of a varying liquid level. The switching alarm points are separated from each other by approximately 1.5 inches.

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