200 Level

202 - Chapter 1

Direct Drives

The first pumps used for water gardens in this country, Direct Drives, were originally developed for sump and sewage duty back when operating costs were less of a factor, and are still a favorite of contractors for their strength and durability. These pumps are called Direct Drives because the impeller is directly connected to the electric motor via a shaft. The impeller has to be in the water, and the motor has to stay dry, so the shaft needs to have seals, usually two or three, that keep the water out of the motor. The seals have to work whether the motor is running or stopped, hot or cold, and the impellers are typically heavy, so the motor has to be strong enough to overcome the resistance of the seals and impeller, and that takes power, which costs money. Still, if you need a pump that can chop through algae, or can pump to very high heads, Direct Drives are the way to go.