It's not impossible to adapt an electric or hydraulic motor for complete submersion in water, but it is a costly, complicated and time-consuming exercise. Nevertheless, some industries have a real need for such drives and Huco Dynatork believes it has the answer in a new, fully submersible version of its basic air motor product. These acetal bodied models with stainless steel shafts and bearings are suitable for any motion control application underwater such as opening a valve or for propelling a stirring mechanism.
In common with the standard range, these new submersible motors are just the job for constant start/stop applications under load and can even be applied to give similar characteristics to those of a stepper motor. Reverse operation is achieved by using 5-port control valves, giving near instant response, even under load.
The Huco Dynatork air motor requires around 80% less compressed air than vane motors, providing significant cost savings even at maximum torque. Free-floating pistons transmit maximum torque on start-up, which can be adjusted via a pressure regulator. If a compressed air line is not available, the motor will run continually for more than 15 minutes from a standard diving cylinder.
Another development that is already generating considerable interest in the nuclear industry is a non-magnetic air motor combining stainless steel shafts and ceramic bearings. Particle accelerators and systems such as MRI scanners are typical areas where these non-magnetic motors can be used with confidence.