A butterfly valve, comprising: a valve body, including: a valve bore passing through the valve body, with the valve bore including an upstream valve bore portion and a downstream valve bore portion the upstream valve bore portion and the downstream valve bore portion comprise a tapered upstream valve bore portion and a tapered downstream valve bore portion wherein both the tapered upstream valve bore portion and the downstream valve bore portion taper towards a shaft bore; and the shaft bore located between the upstream valve bore portion and the downstream valve bore portion; a valve shaft located in the shaft bore and extending substantially across the valve bore; and a valve flap affixed to the valve shaft and configured to be rotated by the valve shaft, with the valve flap being configured to rotate between a closed orientation blocking the valve bore and an open orientation, with the valve flap being affixed on an upstream valve bore portion side of the valve shaft, wherein incoming fluid presses the valve flap against the valve shaft, characterized in that the valve flap physically and thermally shields the valve shaft from the incoming fluid in the upstream valve bore portion, and in that the valve bore further comprises one or more bore shoulders formed in the valve body and that are non-aligned with flow through the valve bore, and with the valve flap further comprising a face seal configured to substantially lap over the one or more bore shoulders when the valve flap is in the closed orientation. a valve body, including: a valve bore passing through the valve body, with the valve bore including an upstream valve bore portion and a downstream valve bore portion the upstream valve bore portion and the downstream valve bore portion comprise a tapered upstream valve bore portion and a tapered downstream valve bore portion wherein both the tapered upstream valve bore portion and the downstream valve bore portion taper towards a shaft bore; and the shaft bore located between the upstream valve bore portion and the downstream valve bore portion; a valve shaft located in the shaft bore and extending substantially across the valve bore; and a valve flap affixed to the valve shaft and configured to be rotated by the valve shaft, with the valve flap being configured to rotate between a closed orientation blocking the valve bore and an open orientation, with the valve flap being affixed on an upstream valve bore portion side of the valve shaft, wherein incoming fluid presses the valve flap against the valve shaft, a valve bore passing through the valve body, with the valve bore including an upstream valve bore portion and a downstream valve bore portion the upstream valve bore portion and the downstream valve bore portion comprise a tapered upstream valve bore portion and a tapered downstream valve bore portion wherein both the tapered upstream valve bore portion and the downstream valve bore portion taper towards a shaft bore; and the shaft bore located between the upstream valve bore portion and the downstream valve bore portion; a valve shaft located in the shaft bore and extending substantially across the valve bore; and a valve flap affixed to the valve shaft and configured to be rotated by the valve shaft, with the valve flap being configured to rotate between a closed orientation blocking the valve bore and an open orientation, with the valve flap being affixed on an upstream valve bore portion side of the valve shaft, wherein incoming fluid presses the valve flap against the valve shaft, characterized in that the valve flap physically and thermally shields the valve shaft from the incoming fluid in the upstream valve bore portion, and in that the valve bore further comprises one or more bore shoulders formed in the valve body and that are non-aligned with flow through the valve bore, and with the valve flap further comprising a face seal configured to substantially lap over the one or more bore shoulders when the valve flap is in the closed orientation.