Two pump technologies make the cut for machine tool application

16 February, 2018

The application was for coolant handling on a large, bespoke matching centre. These machine tools are expensive and run at very high speeds generating enormous heat at their cutting surfaces. This particular design included a deep boring function and required a reliable supply of high pressure fluid to cool and lubricate its cutting tools while also flushing away swarf particles away from the immediate cutting area.

The coolant was a viscous synthetic oil and the machine used a complete system complete with several high-volume sumps and a custom-built filtration system. Applied pump selected two pumps for the system.

Return pump

Coolant, once supplied under pressure to the immediate cutting area, hot gushed away and ran back to a collection sump under gravity. From here, it then had to be re-fed back through a cooling and filtration system to a main holding tank ready to be used again. Applied Pumps supplied a Victor ‘S’ series, cast-iron, self-priming centrifugal pump for this purpose.

Victor self-priming pumps have an open, non-clogging impeller that can handle heavily aerated fluids. The pump also has a special abrasion-resistant type shaft seal with an auto-lubrication cartridge. Also, and very importantly, all of the pump’s internal wearing parts are replaceable.

• Duty: 400 Litre/min at 12m differential head.

• Supply: Victor S50 G31T fitted with a 3ph 2.2kW 2-pole motor.

Coolant feed pump

After cooling and filtering, the returned oil was held in a holding sump ready for use again. The requirement then was for a pump to deliver a high volume of pressurised coolant to the cutting area, which had to be completely reliable and constant.

Applied pumps selected a Settima triple screw pump for this part of the system. The pump chosen was cast-iron with hardened screws and a special hard-faced shaft seal. The fluid at this point had been filtered but nevertheless it was decided to play safe with a robust pump design. Triple screw pumps are excellent for supplying a smooth, high volume flow of high pressure fluid, and being positive displacement pumps their volumetric output is proportional to their shaft speed. This was important as the machine tool had several operating points; meaning any pump had to be of variable speed.

• Duty-1: 225 Litre/min at 25 barG.

• Duty-2: 1,125 Litre/min at 7 barG.

• Supply: Settima GR110 SMT16B-2300L G HA TMK 22U31 fitted with 3ph 22kW 4-pole motor fitted with PTCs for use with a VFD.

Supplier integrity and equipment quality was essential for the customer. The cutting forces generated by large modern machine tools are high and failure of the coolant supply, even for a short period, would be catastrophic.

www.appliedpumps.co.uk