Abstract: 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.

Abstract: A dual orifice venturi vacuum drawback assembly includes a fluid supply passage that supplies fluid to the device, a fluid return passage that returns fluid from the device, a shutoff valve position on the fluid supply passage, a bypass passage, a bypass valve positioned on the bypass passage, and a dual orifice venturi valve. The bypass passage includes an inlet connected to the fluid supply passage upstream of the shutoff valve, and an outlet connected to the fluid return passage. The dual orifice venturi valve is positioned on the bypass passage upstream of the bypass valve. The dual orifice venturi valve includes a venturi inlet, a venturi outlet, a primary orifice, and a secondary orifice. The primary orifice is connected to a primary drawback opening on the fluid return passage. The secondary orifice is connected to a secondary drawback opening on the fluid return passage.

Abstract: 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.

Abstract: A flow meter having a housing with an inlet, an outlet and a cylindrical housing chamber fluidly connected in series between the inlet and the outlet. A cylindrical rotor is rotatably mounted within the housing chamber about an axis which is eccentric with respect to the axis of the housing chamber. In addition, a plurality of circumferentially spaced vanes are radially slidably mounted within the rotor. These vanes are urged radially outwardly into sealing contact with a housing wall which defines the housing chamber. A fluid working chamber is formed between each pair of vanes, the outer periphery of the rotor and the housing wall and this working chamber increases in size from the housing inlet and to the housing outlet. In operation, fluid flow into the housing inlet rotatably drives the rotor until the fluid is exhausted through the housing outlet. A detector detects the speed of rotation of the rotor thereby providing an indication of the fluid flow rate through the flow meter.

Abstract: A flow meter includes a transparent tubular housing in which an indicator in the form of a piston having a radially expanded edge cooperates with a tapered inner peripheral wall portion of the housing. The housing can include scale indicia of flow rates coinciding with positions of the indicator edge. In addition, a temperature sensitive label providing a visible indication of fluid temperature can be orthogonally aligned with respect to the flow rate scale to permit accurate placement of a graphic overlay exhibiting representations of a different fluid characteristic which varies with changes in the flow rate and temperature of the fluid within the ranges indicated by the meter. Projection of the temperature indication to the indicator edge identifies a particular value for the fluid characteristic shown on the graphic representation by mere observation.

Abstract: The present invention provides a device for generating an electrical output signal representative of the flow rate through a fluid flow meter of the type having a mechanical output member movable in an amount proportional to the fluid flow rate. The device comprises the U-shaped magnet having a north and south pole and a Hall effect transducer positioned between the poles of the magnet. The transducer produces an electrical signal representative of the distance between the transducer and one of the magnetic poles. The magnet in turn is connected to the mechanical output member from the flow meter so that the magnet moves in unison with the output member from the flow meter thus varying the transducer electrical output. The output from the transducer is electrically connected to a conventional electrical indicator to produce an indication of the fluid flow rate through the flow meter.

Abstract: A fluid flow meter comprising a housing having a fluid inlet, a fluid outlet and defining an internal fluid chamber. A fluid passageway is formed in the housing for connecting the inlet with one end of the chamber while the outlet is open to the other end of the fluid chamber. The ends of the chamber are closed at the outlet end by an end cap and the other inlet end by a cartridge assembly which includes an end cap. Central to the housing fluid passageway and to the inlet end cap is attached to a rod having a conical metering portion. Attached to the metering rod is a freely centering piston assembly sealed nearest the outlet end by a flexible seal. An axial bore is formed through the piston and an orifice plate is detachably secured to the piston at near midpoint in the axial bore. One side of the plate is open to the inlet end while the other side of the plate is open to the outlet end of the chamber.