GB857617A - Improvements in pressure cookers - Google Patents

Abstract

857,617. Lids for resisting fluid pressure. KELLER, M. April 17, 1958 [April 26, 1957], No. 12188/58. Class 123(1) A pressure cooker has a pot 1 with an outturned rim formed with spaced lugs 3 and a lid 7 having a depending cylindrical edge portion 8 with inturned lugs 9, the lugs 9 passing between the lugs 3 when the lid is placed on the pot and engaging thereunder as the lid is rotated to lock it in position, when the lid handle 10 lies above the pot handle 4. The pot is sealed by a resilient packing ring 22 housed within the lid portion 8 and having arms 23, 24 which in use are respectively forced against the lid and the pot rim as the pressure in the pot increases above atmospheric. If the pressure becomes excessive a part of the ring 22 is forced outwardly through a slot 25 in the edge portion 8 and the seal is temporarily broken. To prevent pressure build-up in the pot unless the lid is in the fully-locked position and to prevent the lugs 3, 9 from being disengaged whilst the pot is under pressure a spring- loaded pin 17 is housed in a bore 14 in the handle 10 and has a portion 21 which projects through the edge 8. When the lid is placed on the pot the portion 21 bears on the edge of the pot rim between the flanges 3 and also presses on and distorts the ring 22 to destroy the seal. When the lid is turned to its locked position the pin 17 is forced back into the bore 14 as the portion 21 rides up the oblique edge of one of the lugs 3 allowing the ring 22 to recover its shape and to seal the pot. When the lid is unlocked the pin 17 advances to vent the pot before the lugs 3, 9 disengage.