HBP Series dryers improve air system efficiency by the use of a dedicated axial blower, instead of a percentage of dehydrated purge air, to regenerate the off-line desiccant tower. ISO 8573.1 Class 2 (-40°F/-40°C) dew point performance is guaranteed. HBP Series compressed air dryers will produce the design dew point while operating continuously at maximum rated flow (100% duty cycle) at CAGI ADF 200 inlet standards of 100°F inlet temperature and 100% relative humidity at 100 psig.Blower purge type regenerative compressed air dryers are an economical and reliable way to dry compressed air to dew points below the freezing point of water. Desiccant dryers lower the dew point of compressed air by adsorbing the water vapor present in the compressed air onto the surface of the desiccant. Adsorption continues until equilibrium is reached between the partial pressure of the water vapor in the air and that on the surface of the desiccant. These dryers continuously process compressed air by using two identical towers, each containing a desiccant bed. While one tower is on-stream drying, the other tower is off-stream being regenerated (reactivated, i.e. dried out). The towers are alternated on and off-stream so that dry desiccant is always in contact with the wet compressed air. In this way a continuous supply of dry air down stream of the dryer is possible. The switching from one tower to the other is controlled by a solid-state controller on either a fixed time basis (standard) or a demand basis (optional).