Boosting Process Air Flow

Eldridge has a reputable history in helping our customers with tough ventilation problems, however our team also the expertise to solve difficult process air flow problems.  We recently helped a customer improve their dry air system with a little boost from an Eldridge design enhancement and our equipment.

Identifying the Problem

This particular customer utilizes a dry air distribution system to guarantee product quality in its facility. The customer had recently installed a new desiccant dehumidifier to provide the required amount of dry air for the system utilizing 100% outside air.

The two key customer requirements of the system were:

• Air must have a low relative humidity (RH) level
• System must provide positive pressure in the areas where the product is processed and packaged

After installing the new desiccant dehumidifier a significant problem transpired.  The required RH level was being maintained, but the required level of positive pressure to prevent outside air infiltration in the processing and packaging areas was not being met.  Our initial assessment of the problem was that the dehumidifier blower was not providing enough pressure.  This was confirmed when we calculated the pressure drop of the duct system used to distribute the dry air to the processing and packaging areas.

A Little Boost Was Needed

Our initial solution to this problem was replacing the dehumidifier blower.  However, we quickly realized this was not the most economical approach.  With a little resourceful thinking we determined a more cost effective solution was to add a single tubeaxial booster fan to each of the two main branches of the duct work.  We recommended using our Eldridge Fan model EDT Direct Drive Tubeaxial fan.  Each model EDT tubeaxial fans were sized to deliver half of the air flow of the dehumidifier blower while still providing the static pressure required for the ductwork downstream from each of the fans.  We also recommended each of the tubeaxial fans be controlled by VFDs, which would allow the customer to maintain the required positive pressure and save money by turning down the dehumidifier output when outside ambient conditions would allow it.   

Conclusion

The customer recently expressed how pleased they were with the economical solution Eldridge designed and equipped.  They now have a dry air system that will maintain both RH level and positive pressure at lower operating costs.  Our customer has been so pleased with our solution, they have requested we design the same retro fit solution for the dry air system at their facility in another state.  We are very happy to have made them an Eldridge customer for life!