Gear pumps are positive displacement Pumps, a popular pumping principle. These are often used for pumping lubricating Liquids, Oils, and other Viscous Liquids. Gear pumps come in either single or double (two sets of gears) pump configurations with spur (shown), helical, and herringbone gears. It is well known that, Helical and herringbone gears typically offer a smoother flow than spur gears, though all gear types are relatively smooth. For this reason, our large-capacity gear pumps use helical or herringbone gears. The small external gear pumps typically operate at 1750 or 3450 rpm whereas the larger models operate at lower speeds. Both sides of the gears have close tolerances and shaft support of the gears. This enables them to operate to pressures beyond 3,000 PSI / 200 BAR, making them well suited for use in hydraulics. Closer & tighter internal clearances ensure a more reliable measure of liquid passing through a pump and allow for greater flow control. Owing to this, gear pumps are always preferred for precise transfer and metering applications involving Polymers, Fuels and Chemical Additives.