Sudden pressure rise detector

Apparatus which activates explosion suppression or isolation equipment and which detects a sudden incipient rise in pressure which could result in a destructive overpressure in a containment system subject to pressure fluctuations during normal operation, said containment system including wall structure defining a region to be protected, said apparatus attached to said containment system and comprising:

• a housing having a first passage provided with means defining a fluid inlet adapted to be connected to the pressurized system at one area thereof;
• a first movable closure means in said first passage which is shiftable in response to application of a predetermined pressure against the one side of the closure means exposed through said first passage inlet to fluid pressure within the system at said area,
• said housing being provided with a second passage provided with means defining a fluid inlet;
• a second movable closure means in said second passage which is shiftable in response to application of a predetermined pressure against the one side of the second closure means which is opposed to said one side of the first closure means exposed to fluid pressure within the system at said area;
• a single pressure equalization conduit operably connected between said first passage and the inlet of said second passage and defining a fluid communication path therebetween to equalize the pressure on said one side of each of the closure means during said on said one side of each of the closure means during said normal pressure fluctuations of the system at said area, said single conduit being defined by wall structure different from said region-defining wall structure;
• means defining a restriction orifice in said conduit between the first passage and said inlet of the second passage of an effective cross-sectional area to limit the rate at which said equalization occurs and thereby produce a difference in the fluid pressure against said one side of each of the closure means when the fluid pressure at said area of the system rises at a rate which could result in a destructive overpressure in the system;
• and
• switch means in the housing for activating said equipment responsive to a predetermined difference in pressure on said one side of each of the closure means which results in movement of at least one of the closure means to a preselected extent.