Shaft Sealing
Compression Packing
Packing Material
New Packing
Static seal is formed at the ends of the packing rings and outside diameter of the
stuffing box.
Dynamic seal is formed between the shaft or shaft sleeve.
After installation
Material should be resilient to compensate for installation variables.
Packing should be adjusted to control leakage.
Stuffing Boxes
Packing Pressure distribution
Stuffing Box Packing
Lantern Rings
Mechanical Shaft Seal
Mechanical Seal
Mechanical seal
Single Seal
Double Mechanical Seal
Double Mechanical Seal
NON-CONTACTING GAS LUBRICATED SEALS A sealing concept has its origin in gas sealing
technology developed for gas compressors in the mid-1970s.
Development of this technology for pumps was accelerated in the early 1990s as a way to control emissions.
Gas, rather than a liquid, must be used as a barrier fluid
one of seal faces must be designed with a lift mechanism.
Spiral groove seal face
LIFT MECHANISM
Can take the shape of a spiral groove, an L-shaped slot, or a controlled wavy surface.
When the shaft turns, pressure builds up in the seal faces. which causes the face separation.
Face separation is very small and could be measured in nanometers, which enables a small amount of gas to flow across the seal face.
Benefits
The only heat that is developed is from the shearing of gas at the seal faces.
The small amount of gas flow helps cool the seal faces.
The preferred seal for heat-sensitive liquids.
Applications
Pumping liquid near its vapor pressure.
The amount of heat generated would require too much cooling to prevent the liquid from flashing.
Allowing the liquid being sealed to flash to a gas and use a non-contacting gas lubricated seal.
For dangerous liquids a tandem seal is utilized.
Bearing