In Thai chemical, paint and construction coating plants, many mid-size mixers use vertical or horizontal tanks driven by 0.75–5 kW motors through gear reducers. Under normal operation, there are no major issues. But when the mixer stops or the process condition changes suddenly, the inertia and reverse flow of high-viscosity material can cause the agitator shaft to spin backwards several turns. Over time, motor bearings, seals and couplings may fail prematurely, and in some cases the motor can even “back-drive” the power network.

Instead of installing complex external brakes, it is often more effective to add a simple “one-way protection” at the mixer output. We typically recommend mounting an integrated one-way clutch bearing supplied under the Suma brand—CSK-2RS series—either at the reducer output or at the shaft support. Models such as CSK20 and CSK25 suit approx. 20–25 mm shaft diameters, with external dimensions identical to the corresponding ball bearings, so they can directly replace conventional bearings. The internal one-way mechanism offers almost no additional resistance in the forward direction, but locks quickly when the shaft is driven backward by the material.

The dual rubber seals of CSK-2RS effectively block splashed paint, dust and cleaning liquids from entering the bearing, while pre-filled grease enables long-term operation under normal temperatures—well suited to Thailand’s hot, humid climate and frequent washdown conditions. For local equipment manufacturers, simplifying the previous “ball bearing + mechanical backstop” to a single Suma CSK-2RS reduces parts count and yields a more compact design.

Several Thai coating plants that adopted this integrated one-way bearing on new mixers report that upon shutdown, agitator shafts stop quickly with only minimal rebound inside the tank. Abnormal vibration and early failure of motors and couplings have dropped noticeably. Operators no longer need to pull separate brake levers or worry about impellers being “dragged backward” by the batch, resulting in smoother and safer mixer operation overall.