3.2.5 Machine tool coolant pumps

Machine tool coolant pumps

Machine tool coolant pumps are used for pumping coolant and cutting liquid for machine tools e.g. lathes, grinding machines etc. Pumps for machine tool applications are divided into low, medium and high pressure pumps depending on application requirement. For a machine tool pump intended to serve a single traditional machine tool unit, volume flow usually varies between approx. 0.3 and 20 m³/h with delivery heads varying between approx. 2 and 20 m. For large scale machine tools application, one pump can supply coolant to many different units and the performance can be specified to flows of 300 m³/h and pressures of up to 200 bar. Machine tool pumps are standardized in accordance with ISO standards for centrifugal pumps or positive displacement pumps depending on pump type.

Coolant pumps for machine tools are designed for the pumping of cooling lubricants for industrial machine tools, condensate transfer, as well as a number of other purposes. They are of various type but multistage, centrifugal pumps that are designed to be placed and fully submersed in the coolant liquid are most common. When higher pressures are required positive displacement pumps like gear pumps (medium pressure), screw and membrane pumps (high pressure) are normally used.

Traditional machine tool pump

The pump unit is constructed so that the pump section is submerged in the liquid, sucking it freely and with the motor placed above the liquid container, figure 3.251. The immersed depth is up to approx. 500 mm. Due to this construction, no shaft seal is required. BS 3766 specifies ten sizes in the form of dimensions and minimum performance characteristics. Normally coolant pumps are manufactured in cast iron or aluminium but there are special types available in plastic or acid resistant steel for pumping different chemicals and acids.