Pneumatic Capacity Control (PACO) for Metering Pumps
AcuFlow’s Pneumatic Capacity Control permits remote pump capacity adjustment from a manual loading station and/or in response to an instrument air signal from a process controller. The AcuFlow pneumatic capacity control is an assembly consisting of three major components,
The Positioner
This is the main part in the pneumatic control, which continuously compares the location of the piston in the pneumatic cylinder with the instrument signal air pressure and regulates the supply air pressure imposed on one side of the piston to obtain the required piston position.
The Pneumatic Cylinder
This cylinder, with a differential area piston, moves the capacity control spool of the pump in response to the signal supplied by the positioner. The cylinder is made of a clear, impact resistant plastic, making the position of the piston visible at all times for comparison against a “percent capacity scale”.
The Mounting Flange
This holds the assembly on to the pump, forms the end of the pneumatic cylinder, and seals off the ID of the piston to establish a differential area between the two sides of the piston.
| Positioner Model No. | Series of Pump Where Used |
|---|---|
| PACO-1 | 1000 |
| PACO-2 | 2000 |
| PACO-3 | 3000 |
Supply Air Requirements
| Feature | Measurements |
|---|---|
| Supply Air Requirements | Clean, Dry & Oil-Free Regulated at 60 PSIG |
| Pump Capacity Variation Over Instrument Air Range | 0-100% Rated Capacity. |
| Minimum Pressure Change Required to Change Capacity | .20 PSI or .13% of full pressure. |
| Repeatable Accuracy of Positioner | Within 1% of full stroke. |
| Supply Air Consumption | 0.4 SCFM |
| Instrument Signal Air Consumption | 0 SCFM |
Instrument Signal Air Requirements
| Feature | Measurements |
|---|---|
| Instrument Signal Air Requirements | 3-15 PSIG = 0-100% |
| Failure Of Supply Air | Moves to 100% capacity position. |
| Failure of Control Air | Moves to 0% capacity position. |
| Supply Air Connection | 1/4” NPT |
| Instrument Signal Air Connection | 1/4” NPT |
Pneumatic Capacity Control’s Air Control Station
The optional AcuFlow Air Control Station permits manual control of the pneumatic capacity control. The unit includes a 3-way valve for switching from automatic to manual control, a manual adjusting knob, and a 3” dial calibrated 0-100% pump capacity with 3-15 PSI auxiliary markings.
Installation
