This type of air motor is commonly used for machines and appliances operating in hot and humid environments, for example in the blast furnaces and foundries of the steel industry or in the injection molding industry.
The primary aim when using air motors in high temperature environments is to ensure they keep working when rising from a cold temperature to a very hot temperature. If certain parts in the motor expand, for example if the rotor dilates and touches the end plates, then the motor will stall bringing your machine to a grinding halt.
So the key is to focus on the expansion coefficient of all the motor’s parts to make sure they keep their dimensions and don’t expand. For this, the choice of materials is paramount, notably for the blades and other rotating parts causing friction. Our technical team at Modec tested the performance of various materials in extremely high temperatures for hundreds of hours before making the final selection. The materials must also be sufficiently robust to withstand wear and tear so as to avoid costly regular maintenance and repair.
Equally important is the design of the mechanics. The parts should be assembled in such a way as to allow for a small margin of expansion without affecting the way the motor runs.
Other critical factors include the choice of lubricating product for the gear box and the type of roller bearings used. We use a form of grease that will not liquefy under high temperatures – if the lubricating grease liquefies there is a danger it will leak out of the gear box, and if insufficient grease remains in the gear box it will overheat. As for the roller bearings, they need to be the right fit and well protected in order to avoid undue exposure to different elements in the environment, such as tiny dust and sand particles often prevalent in steel workshops and foundries, which can lead to rapid deterioration.
In general, air motors are better suited to hot, humid environments than electric motors because they have an integrated cooling system thanks to the cooling effect of expanding air. Electric motors need to be significantly oversized in terms of power, size and weight to withstand high temperatures. Also, electric motors are operated via large panels of expensive switches and wiring that can be prone to rusting or malfunctioning in this type of atmosphere. The initial cost of a pneumatic motor may be greater, but once you factor in the maintenance and replacement costs required for electric motors, then you find air motors give a better return on investment in the long run.
Air motors are also ideal for industries, like the steel industry, which use air in the processing action and therefore have a ready supply of air on site.
At Modec, we pride ourselves on our flexibility and reactivity as we understand that a fast response and quality service can make all the difference to our clients. If you would like to find out more about our high temperature resistant air motors, feel free to call for a chat with one of our experts, or download our case studies !