Compression Packing Flashcards
What are the 3 motions that could be on a pump/compressor?
Rotary
Reciprocating
Helical (spiral combination)
What are the 3 automatic packings?
Cup packing
U-cup packing
V-cup packing
Compression packing principle?
Key factor in jam type packing relies on its impermeability to the fluid it is sealing.
When fibres and yarns are used this is voids in the medium being used. When mechanical Pressure is applied, the packing rings are compressed in the confinement of a stuffing box. Any voids are virtually eliminated, some voids may remain, therefore packing should contain some sort of Saturant to prevent uncontrolled leakage of the fluid.
Note: Roughly 70% of the wear on shafts is from the outermost ring closest to the gland
.
Automatic packing principle?
Moulded packing consists of precisely formed shapes of various materials that seal automatically and are pressure actuated.
What is radial wound packing made of? What is it?
Graphite ribbon that comes in rolls and is radially wrapped around the shaft to form rings.
What is spiral wound and crimped Mettalic packing typically used for?
What’s it made of?
Intended for close tolerances
Babbit, aluminum, copper and other softer metals.
What is a lantern ring?
What are its characteristics?
It is used when the pumps shaft speeds are high and the pumping medium is at a high temp or corrosive/abrasive nature.
It aids the stuffing box in lubricating, sealing, flushing and cooling.
It has radial holes with the cross section of an H.
- The lantern ring does not contact the shaft.
Does compression packing allow leakage?
Yes it is used to throttle the fluid and therefore some leakage occurs.
What are the common materials used for compression packing?
Carbon yarn
Graphite yarn
PTFE fibre
Duck and rubber
Plastic
Metal
Vegetable fibre
Asbestos
What special condition must be taken into consideration when installing spiral wound packing?
Ensure that the spiral is orientated for shaft rotation
What types of packing seal in only one direction?
Cup packing
U-cup packing
V-cup packing
Why is more then one ring of jam packing uses?
Each additional ring filling the stuffing box throttles some of the fluid pressure, also if one ring fails another does the sealing
What are the 2 places in which a lantern ring can be located in the stuffing box?
Under the seal water connection
And
At the bottom of the stuffing box
