Patent ID: 8387656

Claim:
A pressure monitoring device for a paint spray gun, the pressure monitoring device comprising; a housing having an air inlet, an air outlet and an air passage connecting the inlet and the outlet; means for coupling the air inlet with an outlet of a compressed air supply and means for coupling the air outlet with an air inlet of the paint spray gun; a digital pressure gauge housed in the housing and positioned to monitor pressure at a pressure take off point in the air passage; a valve housed in the housing and operable to adjust air flow in the air passage; and valve adjustment means for adjusting an opening of the valve and accessible externally of the housing; wherein the air inlet, air outlet and air passage are shaped and the valve is positioned so as to provide minimal turbulence of air flow and minimal pressure drop through the device; the air inlet and outlet comprise inlet and outlet cavities, respectively, each said cavity having a substantially circular cross-sectioned portion adjacent an entry of the air inlet or an exit of the air outlet, respectively, a substantially segmental cross-sectioned portion passing through a first plane which includes a valve seat of the valve, and a tapered section separating the substantially circular and segmental cross-sectioned portions, said tapered section tapering from the circumference of the circular cross-sectioned portion to the chord of the segmental cross-sectioned portion; the pressure take off point is positioned in the outlet cavity, downstream of the valve seat, in a region where there is minimal turbulence of air flowing through the air passage, and outside a second plane that is perpendicular to a longitudinal axis of the housing and contains an axis of the valve; the segmental cross-sectioned portion of the inlet cavity terminates in a taper extending from the chord to the arc of the segmental cross-sectioned portion; and the pressure take off point is situated either (i) facing the exit of the air outlet across said second plane, or (ii) separated, in a direction parallel to the longitudinal axis of the housing, from the entry of the air inlet by said taper of the segmental cross-sectioned portion of the inlet cavity.