Internal fault indicator for power electrical devices
First Claim
1. A fault indicator for indicating the occurrence of a rapid pressure surge within a housing of an electrical device, the fault indicator comprising:
- a) a barrel capable of being mounted in an opening in a housing of an electrical device;
b) an actuating mechanism comprising;
i) a chamber within the housing, the chamber having at least one orifice communicating between interior and exterior surfaces of the chamber; and
, ii) an actuating member movable in responses to a pressure differential between the interior and exterior surfaces of the chamber; and
, c) a plunger within a bore of the barrel, the plunger biased outwardly in the barrel and normally retained in an armed position by the actuating member;
wherein, when the pressure differential exceeds a positive threshold value, the actuating member is moved and thereby permits the plunger to move outwardly in the bore to a triggered position.
1 Assignment
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Accused Products
Abstract
An internal fault indicator for an electrical device is triggered by a sudden increase in pressure as occurs when an insulation failure creates an electric arc. The heat released in the arc is transferred onto the surrounding volume causing localized overheating, vaporization and decomposition of the insulating material. The resulting pressure surge moves a diaphragm. The movement of the diaphragm releases a spring driven plunger from a barrel which extends through the housing of the electrical device. Prior to activation the plunger is held in an “armed” position by a retaining pin. Upon triggering, the plunger is pushed by the spring until it protrudes from the housing to provide a visual signal of the internal fault. A pressure relief valve may be integrated with the internal fault indicator.
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Citations
30 Claims
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1. A fault indicator for indicating the occurrence of a rapid pressure surge within a housing of an electrical device, the fault indicator comprising:
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a) a barrel capable of being mounted in an opening in a housing of an electrical device;
b) an actuating mechanism comprising;
i) a chamber within the housing, the chamber having at least one orifice communicating between interior and exterior surfaces of the chamber; and
,ii) an actuating member movable in responses to a pressure differential between the interior and exterior surfaces of the chamber; and
,c) a plunger within a bore of the barrel, the plunger biased outwardly in the barrel and normally retained in an armed position by the actuating member;
wherein, when the pressure differential exceeds a positive threshold value, the actuating member is moved and thereby permits the plunger to move outwardly in the bore to a triggered position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A fault indicator for indicating the occurrence of a rapid pressure surge within a housing of an electrical device, the fault indicator comprising:
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a) pressure surge detecting means for moving an actuating member in response to a rapid rise in pressure within a housing of an electrical device;
b) indicator means actuated by the pressure surge detecting means, the indicator means comprising a plunger movably disposed within a bore, the plunger movable outwardly in the bore from an armed position to a triggered position upon movement of the actuating member; and
,c) retaining means for preventing the plunger from becoming separated from the fault indicator.
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29. A method for indicating the occurrence of a rapid pressure surge within a housing of an electrical device, the method comprising:
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a) providing a chamber within a housing of an electrical device, the chamber comprising an enclosed volume and an orifice communicating between the enclosed volume and an air space within the housing and providing a plunger having a hidden portion which is hidden from view;
b) allowing a rapid pressure surge within the housing to displace a wall portion of the chamber inwardly;
c) in response to motion of the wall portion releasing a plunger; and
,d) moving the plunger so that the portion of the plunger which was hidden from view is exposed. - View Dependent Claims (30)
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Specification