Venturi vacuum drawback assemblies and dual orifice venturi valve assemblies

摘要

A venturi vacuum drawback assembly includes a fluid supply passage that supplies the fluid to the device, a fluid return passage that returns the fluid to the device, a shutoff valve positioned on the fluid supply passage, a bypass passage, a bypass valve positioned on the bypass passage, and a venturi valve positioned on the bypass passage downstream of the bypass valve. The bypass passage includes an inlet and an outlet. The inlet is connected to the fluid supply passage upstream of the shutoff valve, and the outlet connected to the fluid return passage. The venturi valve includes a venturi inlet, a venturi outlet, and a primary orifice positioned between the venturi inlet and the venturi outlet. The primary orifice is connected to a drawback opening on the fluid supply passage by a conduit. The drawback opening of the fluid supply passage is positioned downstream of the shutoff valve.