Simple bearings just don’t sound exciting. But don’t let the word “simple” fool you. There is a lot more to bearing technology than appears on the surface, and a poorly operating bearing can result in less than optimal performance, and even equipment failure. Specifically, we would like to talk about Horizontal Paddle Wheel Flocculator Bearings.
Flocculators utilize split journal bearings. Over the years there has been an evolution in bearing materials used in this application, with the objective of improving performance. The water treatment environment is challenging as these plants are full time operations with high load that can often contain large amounts of abrasive grit. Choosing the wrong bearing or shafting materials can result in:
- Corrosion of the housing which can be both an esthetics and performance issue.
- Premature wear of the liner causing misalignment and eventually resulting in shaft breakage and the need for down-time to replace.
- Abrasive materials in the water treating process can cause scoring of the shafts. Again, the result can be shaft breakage.
So, the bottom line is, selecting components made of the right materials can mean much longer periods in between expensive maintenance excursions.
Flocculator Bearing Components Upgrade Options
Bearings have evolved from cast iron housings with bronze liners, to stainless steel beauties, with high-tech composite liners. Some of the specifics on upgraded bearings and benefits are as follows:
Cast Stainless Steel Housing:
- Excellent corrosion resistance
- Pairs are milled for perfect fit and alignment
- Better esthetics make the plant look “top-notch”
- Superior strength
- No weld induced stresses
High-tech Composite Liners:
- Often contain embedded or bonded Teflon™ which is a self-lubricating component
- Many new bearing materials offered are NSF 61 certified
- These composite materials have excellent compressive strength so they are great for high grit applications
- Hydrodynamic properties attract a water layer between the bearing and the shaft, which carries heat away from the area
Description UHMW-PE HPVT
Liner "Heavy Grit" 1-yrs to 2-yrs 3-yrs to 6-yrs
Liner "Light Grit" 3-yrs to 4-yrs 9-yrs to 12-yrs
Liner "Normal" 5-yrs to 7-yrs 15-yrs to 21-yrs
Recommended life: ≤ 1/8″ liner wear
Upgraded Solid Shafting:
- Often upgraded to 17-4ph which is a precipitated, hardened stainless steel alloy
- 17-4ph offers high hardness and strength
- This material is equal in corrosion resistance to 304 SS
- With high hardness it will resist scoring and breakage
Description 304 & 316 SS 17-4 pH
Solid Shaft "Heavy Grit" 3-yrs to 4-yrs 6-yrs to 9-yrs
Solid Shaft "Light Grit" 6-yrs to 8-yrs 12-yrs to 24-yrs
Solid Shaft "Normal" 12-yrs to 18-yrs 27-yrs to 41-yrs
Recommended life: ≤ 1/16″ grooves in shaft
When planning your next new plant, or upgrade of an existing plant, you might want to look for particular bearing upgrades that will benefit your process. It is important to fully understand the service environment when shopping for Flocculator equipment with bearings that offer the best in technologies as described above. Taking a moment or two to specify the right materials at the onset of the design process will save expensive maintenance and downtime in the end.