Sealing Ribbon Blenders.
Ribbon blenders are the workhorse of dry-solids and paste mixing. The main agitator shaft runs slow (15 to 60 RPM) and benefits from a standard rotary seal; the chopper, when fitted, runs at 3,600 RPM and needs a dedicated chopper seal. Most plants run both seals from the same supplier for parts commonality.
01The equipment
What an ribbon blenders actually is.
A ribbon blender is a horizontal trough with two helical ribbons attached to a horizontal shaft. The ribbons turn slowly and convey product axially across the trough, achieving uniform mixing. Many ribbon blenders include a high-speed chopper or intensifier shaft for breaking agglomerates.
02Failure modes
Why sealing this equipment is hard.
- 01
Reversing rotation on batch service
Many ribbon blenders reverse direction at the end of a batch to reverse the ribbon's conveying. Lip seals fail in days under reversing service; the 7500 and 7800 are direction-agnostic.
- 02
Daily caustic CIP on sanitary blenders
Food and pharma ribbon blenders are CIP-cleaned daily. EPDM secondaries spec'd for caustic and Ra ≤ 32 µin polished surfaces are mandatory.
- 03
High-speed chopper shaft sealing
Chopper shafts at 3,600 RPM are outside the design envelope of standard rotary seals. The dedicated Chopper Seal is the right answer for this location.
- 04
Crystalline product migration
Sugar, lactose, and salt are crystalline solids that migrate through any pocket in the seal cavity. Crevice-free housings prevent the migration; cast or pocketed housings retain product across changeovers.
03Recommended series
What we ship for ribbon blenders.
All-stainless, washdown-rated seal for food, dairy, and pharma equipment.
Specs Series7500Workhorse seal for screw conveyors, mixers, and dry bulk handling.
Specs SeriesCHOPEngineered for the 3,600 RPM chopper, not adapted from a slow-speed seal.
Specs Series9700When the process is mean — strong acids, hot brine, abrasive slurries.
Specs04Industries that use this equipment
Where you'll find ribbon blenders in production.
05Engineering FAQ
What plant engineers ask before specifying.
Ribbon Blenders · sized in 24 hours
Get a sized seal recommendation for your ribbon blenders.
Send shaft size, OEM make and model, and the operating envelope. We respond with a sized series, materials, and pricing — typically within one business day.