CinchSeal | 23b Roland Avenue, Mount Laurel, NJ 08054 | Phone: 1-856-662-5162

CinchSeal / Rotary Shaft Seal Overview

Rotary Shaft Seals – An Overview

Air Purge SealCinchSeals are unique and provide industrial shaft seal solutions for various industries. Our problem solving sealing devices are designed to seal powder, slurries, or bulk materials on processing equipment. They are effective powder or slurry rotary shaft seals used to reduce product loss, eliminate housekeeping issues, and prevent bearing and equipment downtime in today’s demanding industrial processing plants.

Benefits of CinchSeal Rotary Shaft Seals

Cost savings: Our rotary shaft seals eliminate material loss, maintenance costs, prevent bearing failure, shaft damage, and save money by less power consumption.

Durability: Our rotary seal design was created to thrive/work in some of the most rigorous and hostile environments in the food and bulk processing industries.

Environment Safety: Ensure the safety of employees and their work environments, minimizing area contamination with our industrial seals.

Repairs: All shaft seal designs are able to accommodate repair / rebuild kits

How Our Rotary Shaft Seal Works

The ptfe or hard coated aluminum rotor cups are mounted on the silicone boot and turn with the shaft to create the primary seal face with the stator plates. The stator plates are the sacrificial surfaces and are designed to wear.

Because the cups are mounted to the boot, the rotary assembly floats with the shaft accepting ¼” misalignment that is common to bulk handling equipment.

Why We Air Purge Our Seals

The CinchSeals are purged with air, or if air isn’t available they can be purged with silicone grease. If grease is used, the customer must put in enough grease to fill the whole cavity, until you start to see grease leaking out of the Teflon® faces. We prefer the customer use air, but understand it isn’t always an option. When you use air purge seals, there are 3 major things to remember.

First, when the air is piped from existing plant air directly into the seal, it creates pressure to push the rotor against the stator and closes the sliding interface to stop any material from going into or out of the screw conveyor.

Second, we tell people to set their air gauges 5 to 7 psi higher than the vessel pressure, so that we have a higher pressure in the seal than outside of it, which creates an air barrier to keep product out of the seal.

And last, the air keeps the rotating seal faces cooler by reducing temperature caused by friction. This helps prolong the life of the seal as well. From our experience, customers usually get 1 to 2 times longer life out of their seals when they use air.

Why the Competition’s Seals Fail

Air Purge SealThe most popular shaft sealing equipment you see in the field, mechanical packing, is ineffective, requiring high maintenance. Standard gland seals such as packing glands or split gland seals use square packing that is compressed around the shaft to create a seal between the shaft and seal housing. The packing is designed to wear with normal operation, and based on the severity of the product being sealed, will need to be replaced very frequently. Also, with axial runout of the shaft, the packing gets beat up which creates gaps for material to get through and leak out. Our seal can handle up to .25” of shaft runout.

With abrasive bulk materials, the material will migrate into the seal area and become impregnated into the rope packing. The abrasive material will begin to wear down the shaft and the packing. This creates an area for material to escape and leak out of, not to mention damaging the shaft, making the surface uneven and difficult to seal. Packing also has to be maintained, removed, and re-packed, which is costly and labor intensive. The CinchSeal easily bolts up thanks to our self-adjusting design; the customer will have almost zero maintenance for thousands of hours.

Internal Mechanism

Air Purge Seal
The molded elastomer boot seals the shaft statically without damaging or wearing the shaft or the shaft seal material.

The silicone boot will withstand temperatures up to 425 degrees F.

The elastomer boot material is an FDA approved silicone that will handle 95% of industrial applications in the field. This lowers inventory and price, and reduces material selection errors.

Parts of the Seal

The PTFE stators and rotor cups are made out of special mineral filled Teflon® with 15% of a binding agent Wollastonite. The hard coat aluminum rotor cups used for abrasive applications are rated at a rockwell hardness of 62, which is just below diamond.


Temperature Ranges:

  • Poly housing with air purge up to 180°F
  • Aluminum or 316 stainless steel up to the high temperature of 400°F

Can Withstand:

  • Up to 28 inches of vacuum
  • Up to 65 psi operating pressure
  • Purge seal with 5 to 7 psi of air above operating vessel pressure for optimum performance


  • Screw conveyor seal – up to 60 rpm
  • Mixer seal – up to 225 rpm
  • Chopper seal – up to 3600 rpm
  • Notify the factory when application is above 60 rpm for screw conveyor seal or 225 rpm for mixer seal
  • Maximum surface speeds approx. 1200 feet per minute


  • Seal housing is available in Aluminum and 316 Stainless Steel depending on customer’s needs.
  • Hastelloy C 276 and titanium can be used when required.

CinchSeal is a trusted and experienced rotary shaft seal manufacturer. Contact us to learn more about the production of rotary seals or to get industrial seals for your business!