A Kates Flow Rate Controller controls flow by maintaining a constant pressure differential across a metered orifice. The simplicity of its design begins with the Internal Differential Regulating Valve (IDRV).

When fully extended the IDRV will cover the exit port. When the inlet pressure is applied, the top of the impeller sees the upstream pressure, P1, and is forced down. Subsequently, fluid flows through the metered orifice resulting in an internal pressure, P2. Further pressure is dropped across the exit orifice resulting in the discharge pressure, P3.

The IDRV is in an equilibrium when the upstream pressure is reacted by the internal pressure plus the force of the spring. If the internal pressure is too low, then the IDRV will move down decreasing the area of the exit port. This will in turn increase the internal pressure. Thus the pressure across the impeller, as well as the metered orifice, is maintained to be constant. When the upstream pressure fluctuates, the internal pressure will adjust accordingly. When the downstream pressure fluctuates, the IDRV will adjust the size of the exit port to maintain the internal pressure.

The flow rate can be adjusted by changing the area of metered orifice. This is done through the control knob on the top of the flow rate controller.

With a Kates Flow Rate Controller, the user maintains flow to within 1-1/2% of the setpoint, regardless of pressure variations. Just set it and forget it!