#1 Choice for Waterjet Cutting, Pump and Seal Repairs, Custom Die Making, Machining, Gasket Cutting, Gasket Materials, Rubber Extrusions, Pump Packing, Pipe Couplings and Gasket Making Tools.

Environment Determines Seal Type

Guide to Mechanical Seal Types and Component Properties - Page 4

The balanced seal has the same opening area as the unbalanced seal, but the closing area has been reduced in relation to the face area. Because force = pressure x area, reducing the closing area reduces the closing force: less heat is generated, and the seal generally has a longer life.

Seals can be further classified in a number of ways. There are four additional classifications of mechanical seals which can be described by distinct characteristics:

  • Rotary spring, springs or bellows rotate with the shaft.
  • Stationary spring, springs or bellows do not rotate with the shaft.
  • Non-Metallic, no metal parts come in contact with the fluid being pumped.
  • All Metal, metal parts are used exclusively where application temperatures require it.

Temperature Chart

Temperature Inside Outside
Balanced Unbal. Balanced Unbal.
Up to 250 °F
Up to 120 °C
* * * *
250 °F to 400 °C
120 °F to 205 °C
* * *
Up to 400 °F
Up to 205 °C
*

Pressure Chart

Pressure Inside Outside
Balanced Unbal. Balanced Unbal.
Up to 150 psi
Up to 3.5 kg/cm2
* * * *
150 psi to 300 psi
3.5 kg/cm2 to 21.1 kg/cm2
* *
Over 300 psi
Over 21.1 kg/cm2
*

Speed Chart

Speed Inside Outside
Balanced Unbal. Balanced Unbal.
Up to 1500 fpm
Up to 7.6 rpm
* * * *
1500 to 3000 fpm
7.6 to 15.2 rpm
* * *
Over 3000 fpm
Over 15.2 rpm
*
  • fpm = Feet per Minute
  • rpm = Revolutions per Minute
  • psi = Pounds per Square Inch
  • kg/cm2 = Kilograms per Centimeter Squared

View Full Catalog of Products & Services