These currents power the actuating devices responsible for the pumping action of a metering pump. This particular type of positive displacement pump is lauded for extreme accuracy and reproducibility throughout continuous precision operation. The cyclical introduction of consistent amounts of fluid into a continuous-flow stream ensures the homogeneity integral to many fluid based industrial and commercial processes.
Chemical, pharmaceutical, food and beverage processing, water treatment, medical commercial vending, irrigation, petroleum, milling, plastic fabrication, metalworking and a number of other industries employ metering systems in daily operations. Although alternative power sources such as pneumatic, hydraulic, manual or fuel powered pumping are widely available, electronic metering pumps more easily incorporate current technology such as digital and computerized metering equipment.
Unlike manually operated pumps, computer automation allows for easy adjustments to be made without interrupting the fluid flow or cycle. AC and DC electrical currents are most often utilized, though electronic metering pumps can also operate under the power of the electricity generated by wind, water and solar power. In applications where continuous flow is essential, such as medical dispensing pumps for example, it is beneficial to have a backup generator or battery regardless of the type of electricity in use in case of electrical failure.
The two predominant electrical currents used in the modern manufacturing and operation of metering pumps are AC and DC, differentiated by the flow or directionality of the electrons. Direct current, DC, voltage is created through the use of a magnetic field surrounding the wiring which causes the electricity to flow in one direction as they are repelled and attracted by the magnetic polls. This flow is in a single, forward direction.
AC, or alternating current electricity uses this same principle but with a rotating magnet that causes the electrons to move back and forth. This allows for farther travel with less energy loss than in DC wiring. Both, however, may still be used for electronic metering pumps. Adapters and transformers convert electricity into the most appropriate type and voltage for a specific pumping machine. This electricity is responsible for instigating the motion of the plunger, bellows or other apparatus used to initiate the continued movement of measured fluids.
Though variable displacement constant speed pumps are commonly electronically operated, it is even more beneficial in fixed displacement variable speed models in which adjustments to the flow rate are controlled solely by the frequency of compression and decompression cycles. Additional considerations for electronic metering pumps are similar to those of all metering pumps and include flow rate, maximum pressure and operating temperature, physical dimensions, material construction, stroke and capacity.