The HD940 Series is the largest offering of Blackmer reciprocating gas compressors, and features flow rates of 125.2 CFM (212 m³/hr) at max rpm. These single-stage, double acting two-cylinder gas compressors are available in both air-cooled (HD942/943), and liquid-cooled (HDL942/943) models. For precise leakage control and to minimize product contamination, the HD940 Series gas compressors are available in double- (HD942/HDL942), or triple-seal (HD943/HDL943) models. Additionally, the S3R oil control seal, a feature only available on HD600 and HD940 Series Compressors, keeps oil in the crankcase and prevents oil migration within the compressor. Compared to competitive compressors, all HD Series Compressors are equipped with thicker and more robust wear parts – piston rings, needle bearings, and high-efficiency valves that will keep the HD Series compressors operating longer than the competition between maintenance cycles. Equipped with an array of features such as a ductile iron head and cylinders, steel pistons and self-adjusting piston rod seals, HD compressors provide maximum performance, energy efficiency, quiet operation, low maintenance cost and reliability under the most severe service conditions.