Decompression Equalization Relief Valve

Aircraft are pressurized to maintain an atmosphere suitable for the comfort and safety of occupants at all levels of flight. When a pressurized airplane is flying at a high altitude, the pressure outside the airplane is considerably lower than inside. Should a cargo compartment experience a sudden decompression while at a high altitude it would set up a sudden pressure differential between the passenger and cargo compartments. The floor of the passenger compartment could be designed to withstand the sudden pressure differential or means could be provided to suddenly equalize the pressure in the two compartments. It is known to use a series of lower sidewall blow out panels held in place with an off-center hinge that pivots to move the panel aside in response to a sudden pressure differential. In U.S. Pat. No. 3,012,572 to Bargetzi et al, a relief valve is mounted to a wall of an equipment housing located in an airplane to allow decompression of the housing if the cabin of the airplane is breached. It was found that a series of sidewall decompression units will allow communication between a passenger and cargo compartment under normal operating conditions while quickly opening to allow decompression in response to a sudden pressure differential.

A pressure relief device extends between body frames of an airplane. The device has a perforated permeable member or section to replace a section of an inner sidewall of a passenger cabin. A duct is formed behind the perforated section with ductwork or a panel extending from the top of the perforated section to an outside wall. The duct which leads from the passenger cabin or compartment into the cargo compartment is blocked off with a pivotally mounted valve. The valve is perforated in a manner to permit flow of air to equalize pressure between the two compartments in response to a low pressure differential, but to open the spring-held closed valve in response to a sudden pressure differential.

FIG. 1 shows a fragmented perspective view of the device of this invention.

FIG. 2 shows a fragmented side elevational sectional view taken along line 2--2 of FIG. 1.

A pressure relief device 10 is mounted in an airplane having a cargo compartment 12, passenger compartment 14, an interior or inside wall 16, an outside wall or shell 18 and a floor panel 20. A section of the inside wall is replaced with a grill member 22 which in this embodiment has a series of perforations or holes 24. A series of fins 26 make up a louver which extends upward from the back side of the grill or perforated member. A panel 28 extends from a T-member 30 located at the top of the grill or perforated member 22 to a T-member 32 located on the outer wall 18. This forms a channel or duct 34 behind the perforated member which communicates between the two compartments. A valve 36 is mounted to a hinge 38 which in turn is mounted to the panel 28 to give a pivotally mounted valve which extends across to close off the channel. A torsion spring 40 is mounted to keep the valve closed under all normal operating conditions. In this embodiment the spring urges the valve to seat on the underside 42 of the lowest of the fins. A series of perforations 44 through the valve permit movement of air through the closed valve to equalize a low pressure differential between the two compartments. The holes are sized so as not to pass sufficient air when the pressure differential is large as would be the case if the cargo compartment should suddenly become depressurized. With a large pressure differential the valve would open to permit free flow of air through the duct.

Under normal operating conditions, the passenger compartment 14 and the cargo compartment 12 would be operating at essentially the same pressure and any minor variations in pressure would be equalized through the holes 44 in the closed valve 36. Should the cargo compartment experience a sudden decompression the pressure in the passenger compartment would act against the valve to quickly open the valve to permit free flow of air into the cargo compartment.