Pulse-Bac HD Motor Assembly - The Pulse-Bac HD is a continuous-duty unit offering 270 CFM at 80" wg. The HD unit is normally offered with a 20-gallon tank but it is also available with an extension assembly for applications calling for the collection of large amounts of dense dust like concrete floor surfacing. This assembly allows the motor head to fit onto standard 40 and 55-gallon drums and it is secured with clamps. The motor assembly will feature the same internal filter arrangement of 3, 10" long, spun bond polyester cartridges that are 95% efficient to 0.1 micron. The unit's patented filtration system pulses one of the three filters every five seconds in rotation to ensure continuous operation in demanding environments like concrete dust collection. The unit pictured here shows the Pulse-Bac vacuum head fitted to a 55-gallon drum with a 4-caster base. This configuration of the Heavy Duty Pulse-Bac is ideal for any vacuum application that generates large amounts dense, fine dust and it can is also work in limited source capture applications for grinding stations as a stand-alone dust collector.