Patent GB-1344969-A (GB)
Title: Catalytic converters for internal combustion engine exhaust  gases
IPC: F01N3/28
Filed: 1972-08-24
Abstract: 1344969 Treating exhaust gas GENERAL MOTORS CORP 24 Aug 1972 [7 Sept 1971 23 Dec 1971 14 June 1972] 39395/72 Heading F1B I. C. engine exhaust gas catalytic convertor comprises an elongated housing formed by two oppositely dished top and bottom plates and encloses and is spaced from a catalyst retainer formed by a pair of oppositely dished plates having substantially co-terminous peripheral flanges which abut each other and are sandwiched between similarly co-terminous flanges of the housing plates, the four plates being sealed together at their peripheral edges and being formed at opposite end portions thereof so as to provide at one end of the housing an exhaust gas inlet in communication with a plenum chamber formed by one housing plate and the opposed retainer plate and, at the other end of said housing, an exhaust gas outlet in communication with a plenum chamber formed by the other housing and retainer plates, said retainer plates being perforated so as to retain catalyst material therein, but permit passage of exhaust gases therethrough from one side to the other of said retainer. The catalyst retainer consists of a top plate 26 and a bottom plate 28 each having regularly spaced perforations 32' formed by shearing the metal along parallel discontinuous lines and pressing out portions of the plate to semi-circular form. The side walls are imperforate and have laterally extending flanges 42 and 44. At the left hand end, as seen in the Figs, both retainer plates are shaped to form semi-cylindrical upwardly concave portions 68, 70 which fit one within the other. Similarly at the right hand end the plates are shaped to form semi-cylindrical downwardly concave portions 72 and 74. The retainer plates are enclosed by a top housing plate 12 and a bottom housing plate 14 which have laterally extending peripheral flanges 42 and 44 and at their ends are formed into semi-cylindrical portions. At the left-hand end the bottom plate semi-cylindrical portion 66 receives the portions 68 and 70 of the retainer plates and with the semi-cylindrical portion 64 of the top plate forms a cylindrical gas inlet 56. Similarly the top plate is formed with a semicylindrical portion 64 at its right hand end which receives the retainer plate portions 72 and 74 and with the bottom plate portion 66 forms a gas outlet. The inlet communicates with a plenum chamber 76, from which the gas passes through the catalyst retainer to a plenum chamber 78 and hence to the outlet 58. The construction is strengthened by the provision of four studs 84 which extend across the catalyst retainer and pass through aligned holes in the retainer and housing plates. Dished washers 90 are fitted over turned-down portions at each end of the studs and are received in depressions formed in the plates. The assembly is completed by welding the flanges together and welding the washers to the studs and plates. A layer of heat insulating material 100 and 101 is applied to the top and bottom surfaces of the housing and held in position by a top cover plate 98 and a bottom cover plate 99. Catalyst is filled into the container through a hole 108, in which a bush 109 is fixed to receive a screw plug 110. Aligned holes 104, 105 and 107 are provided for the insertion of a temperature probe.