Burn rate control valve for gas fired heaters

摘要

A burn rate control valve for gas fired heaters in the form of a +E,fra 1/4+EE turn ball valve having two flow passages through the valve member in which one flow passage is for full gas flow and the other flow passage is smaller in diameter for low gas flow in order to provide a full burn rate or a low burn rate. The two passages are dimensioned and angularly related such that the larger or full burn rate passage essentially provides unrestricted flow when aligned with related ports or piping with the smaller or low burn rate passage being angularly related to the larger passage at an angle less than 90 DEG in order to maintain a flow passageway when the ball valve member is moved to a position with the larger passage perpendicular to the associated ports. This angular relation assures that the smaller flow passage will be opened before the larger flow passage closes too much in order that the burner will not cease to operate and not provide a lower burn rate than intended.