AST Seals Logo

Kerr Pump & Supply is an AST Mechanical Seals distributor for the state of Michigan stocking Mechanical Pump Seals to meet your needs.  We also offer quick delivery, and expert advice on replacing and extending the life of your seals.

Advanced Sealing Technology (AST) is a leading manufacturer of mechanical seals and engineered products. The AST product range includes a complete selection of mechanical seals, components and accessories.

Kerr relies on AST’s expertise accumulated in over 30 years designing reliable mechanical seals for rotating equipment. AST manufactures a complete line of cartridge and component mechanical seals for process pumps. These field-rebuildable AST seals allow pump users control over their budget and schedule.

Mechanical seals are an integral part of a pump used to seal machines between rotating parts (shafts) and stationary parts (pump housing). The seal keeps the pumped product from leaking into the environment. Mechanical seals are subject to less leakage than packaged seals, which saves maintenance time and money in the long run.

Kerr is an AST distributor in Michigan for the following AST solutions:

AST Single Cartridge Seals & Plan 23 Seals

A single cartridge seal is well suited for harsh applications. Because mechanical seals may leak a vapor from the high pressure side to the low pressure side, a single cartridge mechanical seal is generally used if the pumped product poses little risk to the environment.

Single Cartridge Seals AST 70  is a simple-to-install seal because it requires no measuring for installation. This unitized cartridge mounted, balanced, multiple spring seal which requires no measuring for installation. It is the basic mechanical seal of choice for ANSI pumps (including enlarged bore seal chambers), vertical pumps, split case pumps, and many more.

The AST70 is easy to rebuild on site with standard tools.  No measurement is needed – slide the seal onto the shaft, bolt the gland down, then tighten the set screws and remove the centering blocks.    No tear down is required.   The static O-ring eliminates any grooving or fretting of the shaft. The impeller can be adjusted without removing the seal or pump.  Can be used in:

  • Food Processing
  • Corn Processing
  • Chemical Processing
  • Pharmaceuticals
  • Water treatment
  • Mining Services
  • Marine Operations
  • Sugar Refining
  • Petroleum Systems
  • Power and Energy
  • Pulp and Paper
  • Phosphate Production
  • Brewing and Distilling
  • Waste Treatment
AST70 Mechanical Seal

Single Cartridge Seals AST 7023 is the off-the-shelf solution for hot liquid sealing with ANSI Plan 7323 (API Plan 23). Its built-in pumping ring fits in enlarged bore seal chambers on popular ANSI pumps. Liquids pumped near their vapor pressure must be cooled for successful sealing. Hot water, for example, has low lubricity and causes high seal face wear. Flashing can open the seal faces, causing leakage and seal face damage.

API Plan 23 (ANSI Plan 7323) is the most reliable and economical way to cool a seal. The sealed liquid is circulated from the seal chamber (not the pump discharge) through a cooler and back to the seal. Since only the liquid around the seal is cooled, the heat load on the cooler is minimized and process energy is conserved. Cooler fouling is reduced, extending cooler life.

The AST 7023 seal is the off-the-shelf solution for hot liquid sealing. Its built-in pumping ring fits in enlarged bore seal chambers on popular ANSI pumps.

  • No orifice to clog -The low pressure differential (compared to Plan 21) means that no orifice is required to regulate cooling flow.
  • High temperature sealing with standard materials – The AST 7023 seal is cooled and isolated from the hot process. Corrosion rates and elastomer compression set are reduced, and precipitation from dissolved solids is minimized.
  • Field Rebuildable – No more waiting for seal repairs, and no more worries about installing exchange seals that might have previously held hazardous materials, because the AST 7023 is easy to rebuild on site using standard tools.
  • No measurement required – Simply slide the seal onto the shaft, bolt down the gland, tighten the set screws, and remove the centering blocks.
  • Easy Impeller Adjustment – Adjust impeller clearance without removing the seal or dismantling the pump.

Applications include:

  • Boiler feed
  • Boiler circulating
  • Hot hydrocarbons


AST Dual Cartridge Mechanical Seal & Mixer Mechanical Seal



A double cartridge mechanical seal consists of two seals: an inboard seal that keeps the product within the pump housing, and an outboard seal that keeps the flush liquid from leaking into the atmosphere. A double cartridge mechanical seal can be used as a double seal, a tandem seal, or a spare seal, depending on the barrier fluid pressure relative to product pressure.

The AST 80M Seal is a rugged dual mechanical seal built for use in mixers, agitators, double-ended pumps, and other rotating equipment in demanding service. With its large internal clearances, the AST 80M tolerates shaft runout and end play that would make another seal fail.

The AST 80 dual mechanical seal incorporates liquid shear pumping to remove heat from the seal faces, and can be operated with a pressurized barrier or non-pressurized buffer fluid system.

Both the 80 and 80M can be used in three ways:

  1. Double Seal: With barrier fluid pressure higher than product pressure, the AST 80 prevents leakage of toxic or hazardous fluids into the environment. The barrier fluid provides lubrication to seal gases and non-lubricating fluids.
  2. Tandem Seal: By using a buffer fluid with pressure lower than process, the AST 80 can reduce pressure differential across a single set of seal faces.
  3. Spare Seal: With un-pressurized buffer fluid, the outboard seal of the AST 80 runs “at idle” as a standby seal. If the inboard seal fails, the outboard seal provides primary protection, eliminating unscheduled shutdown of batch processes.

AST Outside & Inside Multi Spring Component Seals

AST 50 outside component seal

Mechanical seals are also available as single outside and inside seals.

The AST50 outside component seal is used where an outside seal is required, and can be a low cost replacement for exotic metal seals or for applications with corrosive process fluids that attack inside mechanical seals, because it has no metal parts in contact with the pumped fluid. The outside seal is easily installed and replaced because it has preset spring compression and is not hidden in the stuffing box.

The AST60 inside component seal is a hydraulically balanced inside seal that can’t fret the pump shaft and is an easy upgrade for existing component seal applications. The single inside seal is designed as a reliable, anti-clog seal. The springs are isolated from the pump fluid, allowing flush rates to be reduced.

AST Resources – Brochures & Best Practices


Let the Kerr Sales Engineers design the right solution for your application