Constant flow rate control valve with low pressure drop start

The valve of claim I wherein said second orifice has a generally triangular configuration with a flat downstream side and two sides extending parabolically from said downstream side toward said end wall.

A control valve comprising:

• a valve body having a flow passage;
• a cup member within said flow passage, said cup member having a side wall and an end wall defining an interior of said cup member, said side wall having at least one first orifice extending therethrough, said end wall having at least one second orifice extending therethrough such that fluid flows through said first orifice and said second orifice into said flow passage, said cup member movably disposed in said valve body to vary the area of said first orifice such that the total flow of fluid through said first orifice and said second orifice into said flow passage is substantially constant over a range of pressure differentials across the valve, said end wall having a configured edge defining said second orifice to limit the fluid flow through said second orifice at higher pressure differentials by producing more turbulence around said second orifice, said configured edge having an upstream rounded portion and a downstream flange portion protruding from said rounded portion into said second orifice.

A control valve comprising:

• a valve body having a flow passage;
• a cup member within said flow passage, said cup member having a side wall and an end wall defining an interior of said cup member, said side wall having at least one first orifice extending therethrough, said end wall having at least one second orifice extending therethrough such that fluid flows through said first orifice and said second orifice into said flow passage, said cup member movably disposed in said valve body to vary the area of said first orifice such that the total flow of fluid through said first orifice and said second orifice into said flow passage is substantially constant over a range of pressure differentials across the valve, said end wall having a configured edge defining said second orifice to limit the fluid flow through said second orifice at higher pressure differentials by producing more turbulence around said second orifice, said configured edge having a flange protruding from said end wall into said second orifice.