Will the 7500 bolt to my existing CEMA stuffing box?

Yes for CEMA 200, 300, 400, and 500. Larger conveyors (CEMA 600 and 700) usually use a custom bolt circle — we'll match it on the order, no extra cost.

What about a long screw with an intermediate hanger?

Intermediate hangers are typically welded and the shaft can't be pulled. The Split Seal in carbon steel or stainless is the standard answer for that location.

Can I run a conveyor seal under positive pressure?

Positive-pressure conveyors (typically inert-purged for explosion-safety) require a slightly different seal configuration — the 7500-AB with a higher purge rate handles up to 5 psig differential.

Sealing Screw Conveyors.

Screw conveyors are the most common installed equipment we seal, period. Roughly 70 % of CinchSeal field installations are CEMA screw conveyors — from grain handling at 6 inches to cement-plant kiln feed at 24 inches. The sealing problem is consistent: dry abrasive solids, occasional moisture, intermittent thermal cycling.

01The equipment

What an screw conveyors actually is.

A screw conveyor in CEMA convention is a horizontal or inclined trough containing a rotating screw (auger) that conveys bulk solids. Standard sizes run from CEMA 100 (4-inch screw) to CEMA 700 (24-inch screw). The shaft penetration through the trough end seal is the dominant sealing challenge.

02Failure modes

Why sealing this equipment is hard.

01
Bolt-pattern compatibility with CEMA stuffing boxes
A retrofit seal must bolt to the existing trough end pattern without machining. Our 7500 and 7800 ship in CEMA 200 / 300 / 400 / 500 patterns out of the box.
02
Dry powder migration to bearings
Inboard powder migration scores shafts and grinds bearings. An air-purged contact seal stops it; lip seals don't.
03
Intermittent operation and thermal cycling
Conveyors that run intermittently see ambient cycling. Unlike the kiln feed, ambient cycling is rarely a seal-killer — but condensation in cold-start service can cause flash rust on hardened faces. The 7500-SS variant in 304 SS solves it.
04
Long shafts and intermediate hangers
Long screws (over 20 ft) use intermediate hanger bearings. Sealing the intermediate is harder than sealing the trough end — split designs are often required because the shaft can't be removed.

03Recommended series

What we ship for screw conveyors.

All product series

Series7500

Workhorse seal for screw conveyors, mixers, and dry bulk handling.

Specs Series7800

All-stainless, washdown-rated seal for food, dairy, and pharma equipment.

Specs SeriesSPLIT

Install without pulling bearings — for the shaft you can't dismantle.

Specs Series9700

When the process is mean — strong acids, hot brine, abrasive slurries.

Specs

04Industries that use this equipment

Where you'll find screw conveyors in production.

05Engineering FAQ

What plant engineers ask before specifying.

Screw Conveyors · sized in 24 hours

Get a sized seal recommendation for your screw conveyors.

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.

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