This double inflator unit is designed for building larger Ecoshells. Its has blow back valves that allow you to use just one of the motors, or both. Among some of the advantages of the double Ecoshell inflators, the greatest would be the safety. This unit is designed to run both fans at the same time, mostly at about half speed. If one of the motors were to quit, it would be easy to just turn up the other motor, and replace the broken one. You can imagine having the dome half way built and an inflator going out, not to mention having men on the building when it went off.
The way to use this inflator, is to utilize the double speed control unit which can also be purchased from Grainger (stock #4X797). The total unit should be put on a 30 amp breaker. The maximum amperage of the motor is 12.7 and the maximum amperage of the controller is 10 (we are slightly overloading the speed controller). The motor controller is actually not rated to carry as much current as the motor but as we only use the motor at slower speeds the controller is fine. Warranty for this unit is handled by the manufacturer and we will assemble it for you.
The Ecoshell I is inflated using an industrial line vacuum blowers that is an AMETEK and purchased through Grainger (part # 2M178). It weighs only 9.5 pounds, but is capable of pushing over 100 inches of water column. Great care must be taken not to over inflate because if a sealed Airform is pushed to 100 inches, it would either totally destroy the floor, rip up the Airform or do other serious damage.
The double inflator has a one way valve in the air lines to prevent deflation if one of the blowers shuts off.
The Challenges of Dome Building