Neptune Hydraulic Metering Pumps: The Gold Standard for Chemical Metering Applications
In the world of industrial chemical processing, water treatment, and precision dosing applications, the reliability and accuracy of your metering pump can make or break your entire operation. Whether you're injecting corrosion inhibitors into an oil production system, feeding polymers into a wastewater treatment facility, or dosing precise quantities of chemicals in a manufacturing process, you need equipment that delivers consistent performance day after day, year after year. Neptune hydraulic metering pumps have earned their reputation as industry leaders precisely because they excel in virtually every chemical metering application imaginable.
The Foundation: Superior Hydraulic Design
At the heart of every Neptune metering pump lies an ingenious hydraulic design that sets it apart from mechanical diaphragm alternatives. The Variable Oil By-Pass™ stroke adjustment mechanism represents a fundamental advantage over traditional variable linkage designs. This innovative system allows the piston to power through the complete stroke length at all capacity adjustments, eliminating the stress, wear, and shock associated with lost motion designs that plague competitor products.
What makes this particularly brilliant is how it affects valve performance. During the by-pass portion of both suction and discharge strokes, the valve checks remain idle. This means they have extra time to seat properly, even when handling heavy or viscous liquids. For operators dealing with challenging chemical slurries, high-viscosity polymers, or neat boiler chemicals, this translates to dramatically improved reliability and longer service intervals between maintenance.
The hydraulically balanced PTFE diaphragm eliminates the mechanical stress inherent in mechanically flexed units. Instead of repeatedly bending a diaphragm back and forth—which inevitably leads to fatigue and failure—Neptune's hydraulic design uses fluid pressure to push and pull the diaphragm. This gentle action dramatically extends diaphragm life and reduces the risk of unexpected failures that can shut down critical processes.
Unmatched Versatility Across Applications
One of Neptune's most compelling advantages is the extraordinary range of applications these pumps can handle. From ultra-low volume applications measuring in quarts per day to high-capacity systems delivering over 640 gallons per hour, Neptune offers a solution tailored to your specific needs.
For low-volume, high-pressure applications—such as injecting antifoam agents or corrosion inhibitors in oil and gas production—the 5003-S and 5005-S models deliver flows down to 0.35 gallons per hour while maintaining discharge pressures up to 3,000 psi. This combination of precision at extremely low flow rates with exceptional pressure capabilities is simply unattainable with most competing pump designs.
The 500 Series offers the perfect middle ground for general industrial applications, with simplex capacities ranging from 0.8 to 94 gallons per hour and pressures up to 3,000 psi on select models. The ability to configure these pumps in either simplex or duplex arrangements provides remarkable flexibility. Need redundancy for a critical application? A duplex configuration gives you two independently controlled pumps on a single drive, ensuring continuous operation even during maintenance or in the event of a component failure.
For high-capacity applications such as municipal water treatment or large-scale industrial processing, the 600 and 6000 Series pumps deliver up to 641 gallons per hour while maintaining impressive pressure capabilities up to 4,000 psi. This high-capacity, high-pressure combination makes them ideal for polymer feed systems, large-scale pH adjustment, and other demanding applications where both volume and pressure matter.
Precision and Accuracy You Can Count On
Chemical metering isn't just about moving fluid from point A to point B—it's about delivering exactly the right amount at exactly the right time. Neptune pumps excel in this critical area with accuracy of ±1% of full scale over the range of 10% to 100% of capacity. This level of precision ensures optimal chemical utilization, reduces waste, prevents over-treatment, and maintains process control within tight specifications.
The ten-turn micrometer dial, calibrated in 1% increments, provides operators with precise, repeatable control over flow rates. The bright, color-contrasted dial is protected from corrosion by a clear PVC covering, ensuring readability even in harsh industrial environments. What's particularly clever about Neptune's stroke adjustment mechanism is that it only moves when adjustments are made, eliminating unnecessary wear and extending service life.
For applications requiring automated control, Neptune offers electric stroke length control options. The Advanced Stroke Controller responds to standard 4-20 mA process signals, enabling seamless integration with modern control systems. This automated capacity control allows the pump to adjust chemical feed rates in real-time based on process conditions, pH levels, flow rates, or other critical parameters—all without operator intervention.
Built for Real-World Chemical Compatibility
Chemical compatibility isn't a one-size-fits-all proposition. Different applications demand different materials of construction, and Neptune delivers an impressive array of options to match your specific chemical challenge. The comprehensive material selection includes 316 stainless steel for general chemical resistance and strength, C-20 alloy for superior corrosion resistance in aggressive chemical environments, PVC for cost-effective handling of many acids and alkalis (up to 125°F), and PVDF for exceptional chemical resistance across a broad pH range.
The EZE-CLEAN™ valve system represents another practical innovation that operators genuinely appreciate. These valve cartridges can be removed for cleaning without disturbing the piping connections to the pump. Anyone who has worked with metering pumps knows the frustration of dealing with clogged check valves—breaking connections, draining lines, cleaning valves, and then reassembling everything while hoping you don't introduce leaks. Neptune's design eliminates this headache, dramatically reducing maintenance time and minimizing process disruption.
The internal relief valve automatically protects both the pump and motor from overpressure conditions, providing an essential safety margin that protects your investment. While external relief valves should still be used to protect system piping, this built-in protection ensures that unexpected blockages or valve closures won't damage the pump itself.
Designed for Harsh Environments
Industrial chemical metering often occurs in challenging environments—refineries, wastewater treatment plants, mining operations, offshore platforms. Neptune pumps are engineered to thrive in these demanding conditions. Standard motors feature totally enclosed, fan-cooled (TEFC) construction with built-in automatic thermal overload protection. For hazardous locations, explosion-proof motors are available that meet Class I, Groups C & D and Class II, Groups E, F & G requirements.
The power train operates submerged in oil, providing continuous lubrication and cooling for extended service life. This design choice reflects Neptune's commitment to long-term reliability rather than simply meeting minimum specifications. Components that run cooler and better lubricated last longer—it's that simple.
For critical applications where even momentary pump failure is unacceptable, Neptune offers double-diaphragm leak detection options. This system uses two dry-coupled diaphragms with an evacuated space between them. A pressure switch continuously monitors this space and can immediately shut down the pump and sound an alarm if a diaphragm failure occurs. This prevents contamination of the process fluid by hydraulic oil and allows operators to address issues before they become catastrophic.
The Bottom Line: Reliability, Performance, Peace of Mind
When you specify a Neptune hydraulic metering pump, you're not just buying equipment—you're investing in proven technology backed by decades of real-world application experience. Since 1961, Neptune has focused exclusively on perfecting metering pump design, and that specialization shows in every aspect of their products.
The combination of superior hydraulic design, exceptional material compatibility, precise control, and robust construction makes Neptune pumps the logical choice for virtually any chemical metering application. Whether you're dosing a few ounces per day at 3,000 psi or delivering hundreds of gallons per hour into a municipal treatment system, Neptune has engineered a solution specifically for your needs.
Perhaps most importantly, Neptune pumps deliver the reliability that allows operators to focus on their processes rather than their equipment. When maintenance is straightforward, when adjustments are precise and repeatable, when components are built to last—that's when you achieve true operational excellence. That's what Neptune hydraulic metering pumps deliver, application after application, day after day.
For engineers and operators serious about chemical metering performance, Neptune pumps aren't just a good option—they're the benchmark against which all others are measured.
