Patent ID: 7766034

Claim:
A method of making a valve assembly having a valve body that has a valve seat and a bore downstream of the seat through which fluid under pressure flows when a ball head is displaced from the seat, comprising: for designing the valve assembly selecting a desired static pressure upstream and downstream of the valve assembly; for designing the valve assembly calculating a velocity of fluid flow through the valve assembly as a function of the density of the fluid and the difference between the desired upstream pressure and the downstream pressure; for designing the valve assembly selecting a desired maximum volumetric flow rate for the fluid to flow through the valve assembly; for designing the valve assembly calculating a flow area between a bore downstream of a valve seat and a valve head ball disposed in the bore as a function of the selected maximum volumetric flow rate and the calculated velocity; for designing the valve assembly calculating a valve head ball diameter as a function of the calculated flow area; making a valve head ball with a diameter substantially equal to the calculated valve head ball diameter; making a valve body having a valve seat, a fluid inlet bore to the valve seat with a diameter of at least 70% of the diameter of the valve head ball, and a bore with a concave arcuate section immediately downstream of the valve seat which is non-uniformly tapered with a diameter increasing downstream of the valve seat with a minimum radial gap between the concave arcuate section and the valve head ball when received therein and axially displaced from the valve seat a distance equal to 25% of its diameter of less than 5% of the diameter of the valve head ball; and disposing the valve head ball in the bore downstream of the valve seat.