Formation of Gas Bubbles

Leakage from the piping (such as from fittings) and the transformation of dissolved gases within liquids into gas bubbles may form gas bubbles inside the metering pump and the piping.

The formation of gas bubbles leads to decreased pumped volume and repeatability. It is recommended to degas liquids before pumping.

Operation after Leaving the Metering Pump Inactive for a Long Period

When the metering pump is left filled with fluids for an extended period, a pre-set pumped volume may be altered, or the repeatability may decrease.

The reasons for these phenomena are as follows:

• The elastomer of the wetted parts becomes rigid.
• Anchoring the opening of check valves can occur depending on the fluids used.
• Gas bubbles have been formed within the liquid inside the pump or the piping.

It is possible that some no-load operations can clear these phenomena and recover the initial condition of the metering pump. It is recommended to drain all the fluids from the metering pump when not in operation.

Piping using Soft Tubes

If a soft tubing material such as silicone is used for the piping, there is a possibility that the elasticity of the soft tubing absorbs the suction pressure and the discharge pressure. In this case, it may negatively affect pumped volume and repeatability. It is recommended to use rigid tubing for the piping.

The above list is not exhaustive; other factors can influence pumped volume and repeatability.

Note: Details such as specifications, etc., may be changed without notice.

• List of Metering Pumps

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