Sudden pressure relay having seismic protection

A sudden pressure relay system for activating a circuit, comprising:

• a tank containing a fluid dielectric with a gas space located above the level of the fluid dielectric,
• at least a first detecting means for detecting a sudden increase in gas pressure within the tank, said detecting means including means for making the detecting means insensitive to relatively slow increases in gas pressure within the tank, and
• defeating means for preventing activation of a circuit by the detecting means when the sudden increase in gas pressure is caused by abrupt changes in the dielectric level due to physical disturbances outside the tank,
• said defeating means comprising a second detecting means for detecting a sudden increase in gas pressure within the tank,
• said second detecting means including means for making the second detecting means insensitive to relatively slow increases in gas pressure within the tank,
• said second detecting means being positioned on the tank in spaced relationship with the first detecting means, with each detecting means connected together in such a relationship that the circuit will not be activated unless both detecting means detect a sudden increase in gas pressure at substantially the same instant.

A sudden pressure relay system for activating a circuit, comprising:

• a tank containing a fluid dielectric with a gas space located above the level of the fluid dielectric,
• at least a first detecting means for detecting a sudden increase in gas pressure within the tank, said detecting means including means for making the detecting means insensitive to relatively slow increases in gas pressure within the tank, and
• defeating means for preventing activation of a circuit by the detecting means when the sudden increase in gas pressure is caused by abrupt changes in the dielectric level due to physical disturbances outside the tank,
• said defeating means including at least a first hollow longitudinal member with an opening at each end thereof, with the opening through said member being connected in flow communication relationship with the first detecting means.

A sudden pressure relay system for activating a circuit, comprising:

• a tank containing a fluid dielectric with a gas space located above the level of the fluid dielectric,
• at least a first detecting means for detecting a sudden increase in gas pressure within the tank, said detecting means including means for making the detecting means insensitive to relatively slow increases in gas pressure within the tank, and
• defeating means for preventing activation of a circuit by the detecting means when the sudden increase in gas pressure is caused by abrupt changes in the dielectric level due to physical disturbances outside the tank,
• said defeating means including a container disposed between the first detecting means and the gas space,
• said container including a plurality of small openings in the surface of the container which effectively permit rapid passage of gas through the container and prevent rapid passage of the fluid dielectric through the container.