Patent GB-728480-A (GB)
Title: Improvements in or relating to pressure control mechanism for enclosures such as aircraft cabins
IPC: B64D13/04
Filed: 1953-04-10
Abstract: 728,480. Fluid-pressure servomotor-control systems. GARRETT CORPORATION. April 10, 1953 [May 2, 1952], No. 9759/53. Class 135. Mechanism for controlling the pressure within an enclosure such as an aircraft cabin includes an outflow valve unit 10 having an operating pressure chamber 65, a pressure regulator unit 11 having a control pressure chamber 70, a flexible part such as the diaphragm 85 providing a fluid connection between the two chambers 65, 70 and shock-absorbing mounting means 100 arranged between the two units and connecting them together. This arrangement prevents undamped vibrations being transmitted to the metering pins &c. in the regulator unit 11. The outflow valve comprises a valve member 14 with an inwardly tapered part 15 adapted to co-operate with a seat 17 on a base member 12 secured to the wall of the cabin. The top of the valve member 14 is closed by a cap 34 supporting at its centre a guide sleeve 41. A diaphragm 21 is clamped between the valve member 14 and a flange 33 on the cap 34. This diaphragm 21 is also clamped between a plate 22 and a fixed baffle 18 supported on the hub of a spider 19 and secured thereto by a nut 26 on a reduced part 25 of a guide shaft 24. The space 37 between the cap 34 and the diaphragm 21 is open to the cabin pressure through ports 38. An annular diaphragm 51 is clamped to the top of the cap 34 and also between an annular part 47 and a flanged ring 56 supporting a cover 60 for the valve unit. The part 47 is connected to the base 12 by circumferentially spaced members 48. The valve member is urged to the closed position by a light spring 66 the upper end of which abuts the upper end of an axial extension 61 of the cover 60. The regulator unit 11 comprises a head 75 and a body 76 within which are mounted various pressure control devices adapted to control the pressure in the chambers 65 and 70. These may comprise for instance an isobaric control unit, a low differential pressure control, a high differential pressure control, and a rate of pressure change control as described in Specification 718,674. The body 76 has an aperture 83 in its lower wall 82 larger than the end of the extension 61 and a flexible diaphragm 85 is clamped to the periphery of the aperture 83 and also to the top of the extension, aligned apertures in the diaphragm 85, the top wall 67 of the extension 61, and in a clamping ring 90 being larger than the outside diameter of the sleeve 41 which may thus pass through them as the valve opens. The shock-absorbing units 100 are spaced equiangularly and in the embodiment shown there are four. Each unit 100 comprises a resilient washer 105 with a control boss 106 arranged between a lug or tab 102 on the outflow valve unit and a tab 104 on the regulator unit 11. The tabs 102 are in the form of eyes bent up from a ring 101 brazed.or otherwise secured to the ring 56 and the tabs 104 are similarly formed on a ring 103 fixed to the body 76. Each set of tabs 102, 104 are connected in spaced relation by bolts 107 passing through washers 109 and the resilient bosses 106 and carrying nuts 108.