Liquid Metering Pumps

Liquid metering pumps are commonly used to continuously introduce liquids into a reactor or vessel at elevated pressures. A wide variety of pumps are available to meet various pressure, flow, and control requirements.

Many common pressure and flow requirements associated with Parr reactors and pressure vessels can be handled with high pressure positive displacement pumps such as those in the table below. Special pumps can be furnished to meet requirements outside the range of these pumps. Pumps may be operated from their faceplates or configured to be remotely controlled (setpoint/start/stop) or automated with a Parr controller, such as the Model 4871 Process Controller. Liquid feed lines typically include an inlet filter, reverse-flow check valve, and outlet tubing to the reactor.

Optionally a Coriolis mass flow meter can be provided in series with the pump to verify the actual mass flow rate (low viscosity fluids only). Alternatively, a liquid feed supply vessel on a scale or balance can be included to verify the mass of liquid delivered as a function of time.

For higher viscosity liquids or fluids containing some solids, a diaphragm pump or high-pressure syringe pump may be appropriate. Alternatively, gear pumps can be furnished for high viscosity liquids, although independent flow rate measurement or calibration confirmation may be required for gear pumps. Syringe pumps may also be appropriate for applications requiring very low (<0.01 mL/min) pulseless flow rates, or where high precision liquid delivery is required.

A stirred or non-stirred feed vessel can also be provided. Parr feed vessels can optionally include a heater or welded jacket which can be used to decrease the viscosity of the liquid being pumped. Overhead nitrogen at a controlled pressure can also be provided with any Parr-provided liquid feed vessel, useful for increasing the net positive suction head in the pump suction line to above the required value (i.e. for liquids with a high vapor pressure at the pumping temperature.)