| 摘要 |
<p>663,780. Pressure relieving devices for fluids ; valves. EKCO PRODUCTS CO. Dec. 1, 1948 [June 15, 1948], No. 31128/48. Class 135. A pressure relief plug for a pressure cooker or the like comprises a resilient disc member 18 adapted to be mounted in an opening 20 in the cover 12 of the cooker and a closure member 29 axially movable under fluid pressure in the cooker into sealing engagement with an aperture in the disc member through which it extends, the disc member 18 being distortable under a predetermined excess pressure whereby a valve portion 34 of the closure member is forced through the aperture to release the excess pressure. The aperture comprises a circular upper portion 27 and a substantially elliptical lower portion 28 separated by a shoulder 25. The closure member 29 also has a head portion 31 with a transverse slot 33 and a flange 32 which engages the disc member when the pressure in the cooker is at atmospheric pressure or less. In this position air may pass out of the cooker during an initial heating period or into the cooker to prevent the formation of a vacuum when the cooker is cooling off. Below the valve portion 34 is a stem portion 36 bearing a retaining disc 37 which engages the underside of the disc 18 to prevent the closure member 29 being expelled from the disc member when the predetermined excess pressure is exceeded. The disc member, which is of rubber or a synthetic rubber such as neoprene, has upper and lower flanges 22, 23 whereby it is normally held in the opening 20, the upper flange 22 lying in a recess 21 and having its lower face substantially in the same plane as the shoulder 25. If the aperture 27 becomes clogged with particles of food or other matter, or if for any other reason, the pressure relief means constituted by the valve portion 34 and the deformable flange 26 of the disc member fails to act, the complete disc member 18 with the closure member 29 attached thereto is blown out of the opening 20 at a predetermined higher pressure.</p> |
