Hydraulic Diaphragm Pumps

Neptune Hydraulic Metering Pump

• How does a Neptune hydraulic chemical metering pump operate?

  Neptune hydraulic pumps work by having a plunger reciprocate at a fixed stroke, displacing hydraulic fluid, which actuates a flexible, chemically inert diaphragm to create pumping action. The capacity of the pump is regulated by controlling the volume of hydraulic fluid, which bypasses the diaphragm cavity. Metering accuracy is maintained by a control rod, which allows hydraulic fluid replacement and air venting automatically with each stroke, while also accounting for temperature changes of the hydraulic fluid. Metering accuracy is also ensured by the use of double ball check valves on the suction and discharge of the pump.

• What are the benefits of a Neptune hydraulic chemical metering pump?

  Hydraulic metering pumps offer superior accuracy, reliability and durability for precise fluid dosing in demanding applications, primarily due to their hydraulically balanced diaphragm, which reduces component stress, handles high pressures and ensure precise control for low-volume, critical chemical injections. This leads to less waste and lower maintenance over time compared to other pump designs.

• What are common problems with hydraulic chemical metering pumps?

  As with most chemical metering pumps, issues typically involve valve clogging or diaphragm imbalance due to fluid inconsistencies. Clogging or debris will cause issues with the metering of the pump. Strainers in the suction line are always required. Regarding the diaphragm, these pumps rely on a constant supply of fluid and oil when operating. These fluids surround the diaphragm, keeping it balanced. If one or both fluids are insufficient, the diaphragm will fail and will need to be replaced.

• What is the maintenance process for hydraulic metering pumps?

  Under normal conditions, metering pumps do not require significant maintenance. On a weekly basis, check oil levels, check for leaks, check the ground connection for corrosion, and clean pump surfaces and the surrounding area of dust and debris. After the first 250 hours of operation, you should change the initial oil. Every 4,000 hours or every six months, whichever comes first, you should change the oil, clean the inlet piping strainer and check the external pressure relief valve. You should also replace worn shaft oil seals and tighten all fasteners. If there is a coupling insert, check it for damage and replace it if necessary. On an annual basis, you should clean the check valves, replace O-rings, diaphragms, coupling insert, rolling element bearings and check valves. For low-profile flange styles, you should also apply anti-seize to the motor shaft and gear shaft adapter.