GB1518566A - Rotary end face seal - Google Patents

Abstract

1518566 Seals CRANE PACKING CO 9 Nov 1976 [2 Jan 1976] 46680/76 Heading F2B A rotary end face seal comprises relatively rotatable seal rings 14, 17 having radially contacting sealing surfaces 16, 29 respectively, the ring 17 being located and held against rotation relative to a gland plate 19 and being axially supported in the gland plate 19 with limited contact via a land 33 located at the radially outer region of the ring 17, the design of the seal rings 14, 17 being such that the centroid 31 of an axial section through the ring 17 is located radially inward of the land 33 so that sealing pressures on the contacting surfaces 16, 21 provide a clockwise turning moment about centroid 31 as shown, whilst the centroid 30 of an axial section through the ring 14 is located such that fluid pressures on selected portions of the ring will develop counterclockwise turning moments of force about the centroid of the ring 14. The arrangement is such that the combined effect of each ring 14, 17 tending to twist about its centroid 31, 30 will pinch off face leakage at the outer diameter of the sealing faces 16, 29 and also counteract distortion of the faces 16, 29 caused by pressure and temperature gradients across the surfaces thereof whereby the necessary sealing flatness of the faces 16, 29 is preserved. To achieve the above results, two further conditions are also required. (1) The ratio of the radial sealing faces width to the inner radius of the faces must be in the range of 0À085 to 0À30, and (2) hydro-pads, in the form of lubricant recesses 28, must be provided, and as shown are arranged around the periphery of the seal face 16. The ring 14 is of carbon.