GB855117A - Extreme temperature sealing device - Google Patents

Abstract

855,117. Joint-making packing. PARKER: HANNIFIN CORPORATION. June 18, 1959, No. 21013/59. Class 122 (3). [Also in Groups XXV and XXVIII] A sealing-device for use under extreme temperature conditions, such as from - 300‹ to 1200‹ F., comprises a semi-rigid ring 11, an outer flat rigid retaining-member 10 of less thickness than the ring and adapted to engage the outer periphery of the ring, and an inner separate member 12 adapted to engage the inner periphery of the ring, the inner and outer members being formed of materials having different coefficients of expansion and selectively positioned so that, under extreme variations of temperature, they move relatively together and squeeze the ring. As shown in Fig. 3 applied to a square-flanged pipe-joint 20, 21 of a high temperature installation, the ring 11, which may be of austenitic stainless steel, is of hollow form and is located between the inner and outer members 10, 12, which may be of martensitic and austenitic stainless steels, respectively, the ring being initially compressed at normal room temperature between the pipe flange 20, 21 by bolts 24 so as to make sealing contact as shown. In operation under high-temperature conditions, the outer member 11 expands a certain degree as shown in Fig. 4, but the inner member expands considerably more thereby reducing the distance between the two members and causing the ring to be squeezed into greater sealing contact with the flanges 20, 21 in order to compensate for the movement apart of the latter due to the expansion of the bolts 24. In an extremely cold installation (Fig. 5, not shown), a similar effect may be obtained by reversing the materials for the inner and outer members 10, 12. In the construction shown in Fig. 6 applied to sealing the head of a bolt 30, a hollow ring 35 is located in an outer retaining- member 36, the materials of the bolt and latter member being so chosen as to produce the effect previously described.