Source: {"pile_set_name": "USPTO Backgrounds"}

1. Field of the Invention
This invention relates to improvements in sealing rings and more particularly, but not by way of limitation, to an improved self-sealing ring adapted for utilization with the closure members of valves.
2. Description of the Prior Art
O-rings are in widespread use today for sealing between the closure member of a valve and the valve seat. These sealing members are efficient in that the generally circular cross sectional configuration of the O-rings lend themselves readily for distortion to fill the seal ring groove to provide a sealing for the valve in the closed position thereof. In actual usage, however, it has been found that these O-ring seals are frequently dislodged from the annular recess or groove, particularly in the event that the closure member is a rotatable gate member. When a rotatable gate member is utilized within a valve body, the sealing member is exposed to the full pressure existing within the valve, and during rotation of the gate member an O-ring may be swept from the groove, and any loss of the sealing ring results in a leakage of fluid around the gate member, causing an inefficient valve.
In order to overcome this disadvantage, a flanged sealing was developed as shown in my prior U.S. Pat. No. 2,886,284, issued May 12, 1959, and entitled "Flanged Sealing Ring". Whereas this sealing ring greatly improved the efficiency of the O-ring type sealing in combination with a rotatable gate member in a valve, it has been found that the flexibility of the sealing ring during compression may not be sufficiently great as to afford the maximum sealing efficiency. In addition, it has been found that the outwardly extending flange may require additional reinforcement in some installations.