Mechanical Seals

Styles 73P and 75P

Dual Cartridge Seals
Environmental protection

Flex-A-Seal is a respected leader in the design and manufacture of dual cartridge seals for critical toxic and fugitive emission applications where single seals are not acceptable. The simple idea of a second layer of protection provides the level of assurance that the world has come to expect.
The Style 73P / 75P is the latest new and improved version of the proven style 73 / 75 designs. These new seal designs incorporate many high performance features to help extend seal life.
First a unique integral bidirectional pumping system feature was incorporated.

This feature significantly improves the flow of the barrier fluid providing better heat dissipation which allows the seal faces to run cooler.

The second major improvement was changing the inboard rotary assembly to the Patent pending Plunger-Lock drive.

The torque transmission strength is increased five-fold over traditional cup point set screws. Most importantly, it allows for quick/easy assembly and seal-kit replacement.
The entire drive mechanism is out of the product.
This system eliminates any possibility of sleeve distortion from over-tightened set screws.
There are no set screws to “back out”. The spring-loaded mechanism keeps the lug “trapped” in position.

The Style 73P offers all the advantages of a Stationary Welded Metal Bellows design on the inboard side.

Eliminates all dynamic elastomer problems caused by product and temperature incompatibility.

The Style 75P offers all the advantages of a Stationary Multi Spring Design.

All of the springs are isolated from the product.

The Style 73P / 75P is fully interchangeable. If the product or operating conditions change this dual cartridge seal can be easily converted from a pusher multi spring design to a welded metal bellows design or vice-versa.
Both dual seal designs are hydraulically balanced and can be operated in a pressurized or non-pressurized state.
Simple Cartridge Seal design for easy installation.
Shrouded face designs provides added protection and eliminates troublesome drive pins.
These designs fit pumps with standard and enlarged bores without modification.
Metric sizes are available.
A high performance dual mechanical seal like the Styles 73P / 75P may require a barrier fluid support system that maximizes the seal performance. Flex-A-Seal has a wide range of support system options to handle the simple to the most demanding service conditions.
A more economical SMD is also available for lighter duty services.

Operating Conditions

Max Temp - 400ºF (204ºC)
Consult Flex-A-Seal for higher temperatures

Max Pressure - 300 PSI (20 bar)

Differential Pressure

Style 73P: 15-25 PSIG
*Higher pressure is available consult Flex-A-Seal.
Style 75P: 300 PSIG

Max Speed - 4500 FPM (22 m/sec)

Note: Maximum Temperature / pressure/ speed indicate operating extremes independently and does not imply the seal will function at these extremes at the same time. Contact Flex-A-Seal if you have any more questions.