Pressurized valve seal

Valve (10, 110, 210) comprising a body (12, 112, 212) said body including: a fluid passage (14, 114, 214); a valve seat (16, 116, 216), defining an orifice (35, 135, 235), and including a gland seal (20, 120, 220) including a support surface (26, 126); and a resilient valve seat member (22, 122, 222) disposed within the sealing gland; and having - a sealing valve (32, 132, 232) disposed within the fluid passage and configured to abut against the member valve seat to seal the sealing member valve with the valve seat and thereby close the orifice; characterized in that - the support surface includes a notch (28, 128) and the notch is configured to facilitate application of a fluid pressure on the member valve seat to prevent leakage through the orifice when the sealing member valve it is supported against the valve seat member.