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Sanitary Mechanical Seals

Top entry mixers and bottom entry agitators on sealed tanks will have a mechanical seal of some sort. For many sanitary process vessels, the mixer must have some type of sealing barrier to provide either a dust tight vapor seal, a pressure tight seal to allow pressure and or vacuum in the mixtank, or an aseptic sealing device to provide a hygienic seal between the tank id and the outside of the vessel. There are a variety for mixer use, including single dry running double assemblies with a liquid or gas flush, and a variety of other lip seals and packing materials which can be used. Starting with the least expensive sealing mechanism for a rotating mixer or reactor, we have a simple dust cover assembly, and elastomer lips sealed, a spring-loaded CIP mixer seal, a packing seal, a USP class VI lip seal, a single dry running mixer seal, a single with an aseptic debris well, and then we have higher pressure double, custom steam sterilizable and split options.

Biomixer Seal Replacement/Upgrade

biomixer replacement seal 1

We replace, repair, retrofit and upgrade any Lightnin Biomixer seals (along with other seals). Direct drop in replacement seal, with certs. It is single dry running, 316ss, FDA carbon face vs FDA Silicon carbide face with FDA EPDM elastomers. USP VI elastomers and seal faces are available as well as non-squealing design for upgrades.

Dry Running Mechanical Seals

  • cGMP
  • Available in Single and Dual Cartridge Designs
  • No Seal support needed for most applications… consult factory
  • Nitrogen can be used in both single and dual cartridges in certain applications
  • Special face material for dry running certified FDA, USP Class VI, Bovine Free
  • Upgrade to whisper seal technology, available for low pressure/slow speed applications providing a much quieter environment for operators
  • Available with Aseptic Debris Well

Sanitary Mechanical Seals

  • Assume mixer/agitator design of 350rpm max speed, 50psig at 250f
  • Sizes for 3/8” dia shaft to 6” + available
  • Bottom entry seals and double liquid or gas seals available on request, please call us
  • Private label and volume discounts for large volume OEMs
  • DETAILS OF SEAL: Single or dual dry running mixer seal
  • CARTRIDGE STYLE SEAL- much easier to install than traditional component seal
  • FACES = GRAS Carbon vs Silicon Carbide seal faces (USP VI silicon carbide seal face)
  • DEBRIS WELL = with 1/4” NPT ports and elbow fitting and plugs (TC optional)
  • BASE METAL = 316L SS for bolt up gland and debris well and seal housing
  • SPRINGS = Hast C
  • ELASTOMERS = USP VI EPDM (other elastomers available see options)
  • Cartridge seal is static pressure tested prior to packaging
  • Seal detailed drawing provided
  • Delivery time = 4 weeks or less
  • Helpful Links
  • Mixer Mechanical Seal With Debris Well Drawing
  • Photo Gallery
  • Brochure
  • Squealless


  • Other elastomers available include Silicone, Viton, Buna – upcharge for Kalrez or Chemraz perfluoroelastomer
  • Aseptic cleaning and vacuum packing of seals
  • TC connections on debris well port
  • TC connection caps, gaskets, clamps for inlet/outlet
  • Hast C wetted parts available
  • call for higher speed, pressures over 45psig, high temp, or for us to review any specific sealing application
  • double liquid flush and gas seals
  • CIP/SIP sanitary valves for TC debris well inlet/outlet
  • Private label seals for large volume OEMs
  • We offer repair, retrofit, and reconditioning/pressure testing

Mechanical Seal Repair Services

We supply new, repair and can provide service assistance for any type of problem. Our offering includes:

  • New agitator and mixer seals
  • Sanitary and hygienic options
  • Repair, troubleshooting, and optimization
  • Mixer lip seals, packing, separately mounted seals
  • Mixer seal debris well retrofit and electropolishing
  • FDA mixer lip seals and USP VI agitator elastomers

Cartridge Style Mechanical Seals

  • Much easier and quicker to install than component seals
  • Installation is quicker, easier and no measuring or setting of heights is required
  • Available for mixers, agitators, reactors, pumps and other rotating equipment
  • White Mountain Process repairs and service any manufacturers mixer seal, either single or dual arrangement
  • White Mountain Process offers dry running single and dual cartridge seals – also available with Whisper Quiet Seal Technology

Support Systems

  • Seal support systems are available to support single and dual assemblies in all rotating equipment
  • Seal Support systems available as pressurized or non-pressurized vessels with or without cooling coils
  • Both Single and Dual Seals are pressure tested before being shipped from the factory
  • All instrumentation available as needed to support the seal environment

Mixer Basics

Seals come in all shapes and sizes. Always speak to a professional to ensure that the right seal is chosen for the job. User manuals for equipment may also list the correct replacement seal type. However, there are many to choose from so if unsure, do not guess.

From single to dual, there are six major types to consider. For single seals, there are rotary external seals, mixer split seals or mixer seals. For dual seals there are high viscosity cartridge seals, mixer cartridge seals or slow speed gas cartridge seals. Since a perfect fit is necessary, be sure to have the right seal in mind before making a choice.

Mixer seals are one of the strongest. Rough conditions that are typical for mixers can seriously damage the average seal. However, motion tolerance seals with the ability to shift automatically under pressure can withstand these harsh conditions. This is the only choice for a fully operational mixer. Cartridge, on the other hand, are not built specifically for mixers but rather for interchangeable use.

Sanitary seals are typically used for extra-large, heavy or hard to reach equipment. Most of these seals feature a split design so the equipment does not have to be dismantled to change out a seal. They are also self-lubricating since it is difficult to access the installed seals for maintenance. This keeps them from drying out and cracking. Single or double sanitary mixer seals are often available to meet a variety of needs. Some can be used interchangeably while some equipment requires only a specific seal and will not operate properly with a substitute.

Always make sure the correct replacement seal is chosen to avoid damaging the mixer or agitator and spending excess money to replace a seal an extra time. Most equipment will come with spare parts and seals are often on that list. Be sure to check the spare parts from the manufacturer before purchasing a new one. Also be sure to have a properly trained individual replace the old seal by installing a new one. Someone who is not familiar with the equipment and the installation process could damage both the seal and the mixer. The manufacturer is often able to send an expert to the site to install replacements for a fee if needed.

Serving Mixing Professionals For Over 20 Years Our Clients