compression packing Flashcards
Compression packing must control what a long moving parts?
leakage
Motion on pumps and compressors can be?
rotary, reciprocating or helical (spiral)
True or false, as well as ceiling compression packing can act as a bearing?
true
true or false Automatic packing seals, in one direction only (uses system pressure to help seal) while the squeeze type seals, seal in both directions .
true
Overtightening the packing, increases the what between moving parts
Increases the friction and acts as a brake
Spiral wound packing is installed with the spiral oriented for shaft?
shaft rotation
Radial wound packing is radial wound around the shaft to form ?
rings
What is another word for lantern rings?
seal cages (h shaped with radial holes to allow fluid thru
Compression packing is used to throttle the fluid, and therefore some leakage occurs what is the approximate leakage rate
40-60 drops per minute
What is normally the pump pressure
10-15 psi
Packing material can be carbon yarn-temps up to__F and shaft speeds of ___ ft per minute. Graphite yarn – good all around packing used in strong acids, caustics and chemicals.
600 F
speeds up to 2500 ft per min
Where is graphite yarn used?
Environments were strong, acids caustics, and chemicals are present. It is excellent heat conduct, Tivitt, he and chemical resistance.
Metal packing –foils and coils and can be what material
soft copper, lead Babbitt and aluminium.
Vegetable fibre- cotton and flax and used for?
cold water, brine or cold oil.
packing is staggered how many deg apart?
90 deg
To determine the correct size of packing – measure the shaft diameter and the bore of the stuffing box. Subtract the shaft dia from the bore dia and divide by 2 = cross-section of the packing.
Name for possible causes of premature packing failure
incorect installation
wrong type
wrong size
excessive heat
Name two places in which the lantern ring can’t be located in the stuffing box
under the seal water connnection
at the bottom of the stuffing box
Name three metals commonly used in metallic compression packing
babit
annealed soft copper
aluminum
Which types of packing seal in only One Direction
cup packing
v packing u cup packing
Why must compression packing throttle the fluid?
inorder to seal and control leakage
Lantern ring(steel cage) is it necessary component in all stuff in boxes
false
Not all compression packing situations require lubrication, such as Teflon
What are the purposes of sad trips and compression packing
fills the voids in the yarn and acts as a lubricant
Radial wound packing can come in braid over braid and interlock braid construction
false
Ribbons are wrapped around the shaft several times to produce a thicker ring-shaped to fill the stuffing box. Ribbons cannot be braided to become thicker cross-sectional shape
jam packing can have long run in time true or false?
true - you as the millwright must inspect and make adjustments
true or false ?
roughly 70% of wear on shafts is on the outtermost rings closest to the gland?
true - this is because the mechanical pressure applied by the gland flower is the greatest
