Adjust flow rate with an electronic metering pump
Most metering pumps use a pump head and a motorized mechanism to pump standing water and other liquids at adjustable flow rates. These liquid pumps employ a flow meter that can be set to the speed you desire and are uniquely capable of achieving very high rates of discharge pressure.
In a typical metering pump, liquid is forced through the pump's head, at which point it flows into an inlet that drains to an outlet for final disposal. These pumps are primarily powered by electric motors, though there are petroleum-powered models available on the market as well. The advantage of gas-powered metering pumps is that they're portable and don't require electrical generators to work in remote areas.
Piston Metering Pumps
The majority of metering pumps achieve their suction power with the help of pistons that create positive displacement, forcing pools of standing water through an inlet and into an outlet. Pump heads use check valves, which are opened by low pressure and closed by high pressure. This back-and-forth low-pressure-high-pressure action creates the energy that is needed to get the still water moving.
Non-Piston Metering Pumps
Piston metering pumps sometimes leak, and this is dangerous when you're dealing with chemicals and hazardous waste. In such cases, it is recommended that you use either a metered diaphragm pump or what's known as a peristaltic pump. Peristaltic metering pumps use rollers in place of pistons and are usually powered by electric motors; while they are safe and leak-proof, these pumps are best used at lower pressures because they cannot stand up to high or extreme levels of pressure. Most chemical metering pumps use either a diaphragm or a peristaltic design.
Electronic metering pumps give you more control over the drainage of the standing liquid than most other types of industrial pumps. This control extends both to the flow rate of the liquid being pumped and to the discharge pressure at the outlet point. If you require a machine that gives you precision control over both the flow rate and the outlet discharge rate, a metering pump may well prove to be the best solution.