Neptune™ Chemical Pump Co., a leading manufacturer of chemical metering pumps, designed its Neptune 500-D Series (Duplex) Diaphragm Metering Pumps for frother applications found in coal mine prep plants. In the preparation plant, the Neptune 500-D Series pumps diesel fuel from one pump head to coat the coal and feeds frother (alcohol) from the other pump head, which makes the coal float on top of the slurry so it can be extracted.

The 500-D Series pumps are designed with features that set the standard in the industry. Its EZE-CLEAN™ valve cartridges can be removed from the pump heads without having to disturb the pump’s piping. Neptune’s Variable Oil By-pass™ stroke adjustment provides better valve performance than variable-linkage designs. Other standard features of Neptune pumps include double ball-check valves, internal relief valve, and a hydraulically balanced Teflon® diaphragm for extended life. Optional features available are automatic flow rate adjustment using an electronic stroke controller and variable frequency drives.

The 500-D pump head materials of construction are 316 stainless steel, C-20, PVC, and Kynar. Material options for the ball check valves are 316 stainless body and seat with 316 balls, PVC body and seat with ceramic balls, C-20 body and seat with C20 balls, and Kynar body and seat with ceramic balls. Flow rates at 100 psi (60 Hz) range from 1 to 60 gph (4 to 228 lph) depending on gear ratios of 37, 72, 117 and 144 strokes per minute. Maximum operating pressure is 3,000 psi (207 bar) and maximum temperature of 200ºF (93ºC) for 316 stainless steel and C-20; maximum pressure and temperature of PVC is 400 psi and 125ºF; and the maximum pressure and temperature of Kynar is 150 psi and 200ºF.

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