Neptune Model 481-S and 501-S hydraulic diaphragm metering pumps are built to deliver very low flows, repeatable and accurate ranging down to quarts per day. Discharge pressures are higher than are possible with mechanical diaphragm pumps. Explosion-proof models are available for use in hazardous atmospheres. These pumps are especially popular in oil/gas production, oil recovery and refineries. Typical applications include the injection of antifoam agents, corrosion inhibitors and other additives injected at very low volumes but high pressures. (Refer to curves on reverse side.) These pumps are also used for neat feeding of boiler chemicals.