As a leading designer and manufacturer of innovative plastic bearing solutions, BNL has led the development of anti-clog ‘free flow’ bearing technology for use in the domestic appliance, food processing, water and leisure industry, where low friction properties and clog resistance are particularly important.
Applications such as dishwasher spray arms, spa jets and suction and pressure side pool cleaners, operate solely on water flow and will only function if the water flow from the pump or through the system is used efficiently. The operational parts of these applications are therefore required to be capable of working with very little applied torque. Using BNL’s more traditional thermoplastic bearing technology, starting inertias as low as 0.12Nmm would be considered the norm. However, using the company’s innovative “free flow” bearing designs, torques as low as 0.041Nmm are achieved (compared with similar sized metal options with torque values of around 0.235Nmm and based on standard sealed metal bearing data).
To address the problem of clogging from debris commonly found in the operating environments of these applications, and food processing systems such as bottling & filling, BNL developed an innovative cage and race design. This ‘anti-clog’ bearing technology allows water and debris to flow freely through the bearing, yielding a greater flow path compared to conventional bearing technology.
With all of the sharp edges removed and the ball clearances increased to reduce potential obstruction points, a free flow of water or a smooth and precise rotating jet is guaranteed – even under low pressure and flow conditions. The successful, free passage of liquids and debris through the system prevents clogging of mechanisms leading to time and cost in maintenance and downtime, or even repair or replacement of components.
‘Open Design’ Bearings
With our many years’ experience of spa and pool applications, we understand that the use of a caged bearing is not always practical, for example with smaller diameter bearings. To address this, BNL has also pioneered the development of a cage-less ‘open design’ bearing. Traditional spa and pool cleaner bearing designs typically utilise shields and seals to prevent potentially clogging debris from entering the workings of the bearing, however this can lead to serious problems. The tight seal necessary to keep out debris raises the torque required to turn the bearing and since zero clearances cannot be permanently maintained, the likelihood of bearing seizure caused by debris becoming trapped between the seals and the races increases over time. Additionally, as the bearing wears, the shield can begin to rub on the inner or outer race causing the bearing to essentially become a high friction bushing or cease rotating altogether. Being shield and seal free, BNL’s ‘open design’ bearings ensure bearing seizure and high torque are removed from the equation.
Increased Flow Path
With both concepts, the anti-clog features result in an average of a 114% increase in the flow path compared with traditional designs, as debris that would ordinarily be trapped by a traditional cage design or seal, is instead allowed to pass straight through the bearing. These free flow designs enable a continuous passage of water or liquid through the bearing, allowing any debris to be washed out. The end result is a bearing that continues to function with minimal increases in inertia. Furthermore, the overall resistance to clogging is higher than sealed products due to the increased clearance afforded by the designs.