A fluid control valve comprising: a cover portion with a first inner surface and a first channel , the first channel including a first radial outer wall and a first radial inner wall shorter in length than the first radial outer wall ; a body portion secured to the cover portion , the body portion having a second inner surface and a second channel , the second channel including a second radial outer wall and a second radial inner wall shorter in length than the second radial outer wall , the first and second inner surfaces defining a chamber , the first channel and the second channel circumscribing the chamber , a gap formed to provide a passage from a cavity , which is defined by the first radial outer wall , the first radial inner wall , the second radial outer wall , and the second radial inner wall , to the chamber ; and a diaphragm disposed between the cover portion and the body portion , the diaphragm including a flexible member disposed in the chamber , a lip member circumscribing the flexible member and a tab , an upper surface of the flexible member including a substantially smooth wall portion having a constant radius of curvature which extends part way and circumscribes a central portion , wherein a thickness of the central portion increases in a radial direction from the substantially smooth wall portion to the centre of flexible member such that the upper surface is substantially flat along the central portion , wherein the first channel and the second channel define the cavity that circumscribes the chamber and each channel receives a portion of the lip member and pinches the lip member to seal the fluid control valve and hold the diaphragm . a cover portion with a first inner surface and a first channel , the first channel including a first radial outer wall and a first radial inner wall shorter in length than the first radial outer wall ; a body portion secured to the cover portion , the body portion having a second inner surface and a second channel , the second channel including a second radial outer wall and a second radial inner wall shorter in length than the second radial outer wall , the first and second inner surfaces defining a chamber , the first channel and the second channel circumscribing the chamber , a gap formed to provide a passage from a cavity , which is defined by the first radial outer wall , the first radial inner wall , the second radial outer wall , and the second radial inner wall , to the chamber ; and a diaphragm disposed between the cover portion and the body portion , the diaphragm including a flexible member disposed in the chamber , a lip member circumscribing the flexible member and a tab , an upper surface of the flexible member including a substantially smooth wall portion having a constant radius of curvature which extends part way and circumscribes a central portion , wherein a thickness of the central portion increases in a radial direction from the substantially smooth wall portion to the centre of flexible member such that the upper surface is substantially flat along the central portion , wherein the first channel and the second channel define the cavity that circumscribes the chamber and each channel receives a portion of the lip member and pinches the lip member to seal the fluid control valve and hold the diaphragm . <EOS>