Displacer Operated

Displacer Operated Level Switches

TC Fluid Control offer a range of either ‘in-tank’ or chamber mounted displacer operated switches. The operating principle of this design ensures a positive latching action via a variety of mechanical switch mechanisms to suit the customer needs.

The operation of the displacer type level control is based upon the immersion of a displacer weight. When not submerged, its weight compresses a compensating spring but when the weight becomes submerged, a vertical force is exerted on it allowing the spring to decompress. As the spring moves, a connecting rod moves a magnetic attraction sleeve within an enclosed tube. The switch mechanism (containing a permanent magnet) is mounted outside of the tube and the magnet is attracted to the attraction sleeve as it enters the magnetic field, thereby actuating the switch mechanism. When the displacer level falls, the attraction sleeve moves out of the magnetic field and the switch mechanism return to their original position under gravity.

Once the switch is actuated, a reverse action needs to take place to deactivate the switch. The reverse travel distance required to reset the switch is approximately 10mm at the switch mechanism, this translates to approximately 50mm at the liquid level (assumes a Specific Gravity of 1.0). The ‘differential’ increases or decreases depending on the density of the fluid.

Features and benefits:

• High Pressure and temperature capability – up to ANSI 2500 (PN420) and up to 450 Deg C.
• Reliable, latching ‘positive’ mechanism with high switch current versions
  E Ex approved options ATEX compliant,br>
• Multiple switch points are possible
• Very wide SG range
• Wide range of resistant materials available
• Can be used for ‘floating roof’ tanks