Bearing and Seals Flashcards
With friction bearings, the area of contact is relatively large and the pressure on the material is usually low compared to anti friction bearings.
True or false
True
Friction bearings have 3 types of radial loads, which one shifts thru an arc less than 180 degrees?
Oscillating
The choice of friction bearing and housing depends on load, rotational speed, support design and _______
Direction of pull
A split joint design that can give up to 270 degrees of bearing load (pull from sides and above split) is the ________
Gib joint
Journal bearings can either be split or one piece and have metallic liners made of?
Babbit and brass
Plastic bearings such as nylon will have?
A thermal expansion rate of 10 times that of metal
A fully saturated water expansion rate of .0256 per inch of material
The ability to run without lubrication
All of the above
All of the above
2 of the common babbit bearing alloys are?
Tin and lead
A thick walled split bearing with a spherical seat will?
Self align its bore with the sag in the shaft decreasing edge loading of the bearing.
Babbit completely melts at _______ degrees C, pours at _______ degrees C, and completely solidifies at _______ degrees C
280
370
250
When dealing with Babbit you should NOT?
Have water on the ground or around the pour site
Over heat the Babbit
Use lead unless are is properly ventilated and wearing proper PPE
All of the above
All of the above
When fitting a poured Babbitt bearing, you will relieve the corners of the bottom half of the bearing and add an oil groove to the__________?
Unloaded area of the bearing
To adjust clearance in the split bearing you would?
Take out shims to decrease the clearance
For clearance in a friction bearing the general rule of thumb is .001” clearance per inch of shaft.
True or false
True
When using plastic age you must choose the diameter about equal to the bearing clearance, lay it down on the shaft, add cap and once it has been torqued down and then the cap removed, you will measure the___________?
The width with a plastigage chart
Crush and spread are built into the liner to help with lubrication? True or false
False crush is to set the clearance
Small bushings will have to be ________ to bring the bore to proper diameter?
Reamed
When removing plain bearings from a housing, the housing halves should be match marked. True or false
True
Use a stone to remove any burrs from the journal and polish it with?
Crocus cloth
Always check journal out of round and taper with ________ around the journal and 3 other measurements
6 measurements at 60 degrees
A housing fit check is done by adding .005” shims under the bearing cap and using a .006” lead wire on top of the bearing insert. You then replace cap and torque. Then remove cap and measure the lead wire. Wire should measure _________?
Same as the shim thickness
Using a hole or telescoping gauge to measure the bore diameter, use a ________ to transfer the measurements to a readable number?
Vernier micrometer
When driving a bushing, you should first slightly chamfer the inside and outside edges and then use an adapter with driver, the adapter helps prevent __________ of the bushing?
Improper alignment
Collapsing
Distortion
All of the above
All of the above
An ideal area of contact of a plain bearing after scraping would be spots about _______ over an area of _________ the surface?
1/8”
85%
End float is controlled by the use of a ________?
Thrust bearing
Hydrodynamic bearings need a designated __________ for a given ________ for full film support?
Minimum speed
Load
A plain bearing with an unsteady load at high speeds will develop oil whirl.
True or false
True
Hydrostatic bearings are found on equipment that operates ___________
At a slow speed to form an oil wedge
And with shock loads
Thrust bearings can use direct lubrication and tilting pads to help form the oil wedge.
True or false
True
Embedablilty of a bearing material is it’s?
Ability to hand contaminants
Lift check is used to check _________ clearance?
Radial
Internal and self aligning bearings are used when?
Alignment is impractical
To accommodate angular misalignment when mounting
There are small amounts of shaft wobble
All of the above
All of the above
Anti friction bearing cages
Prevent rolling elements from rubbing
Push the rolling elements thru the loaded area
Guide the rolling elements
All of the above
All of the above
To load the balls into a Conrad bearing you need to squash the outer ring diameter slightly.
True or false
True
When using angular contact bearings in pairs, use the ________ configuration for axial loads in one direction?
Tandem
Cylindrical bearings can handle radial loads only.
True or false
True
Tapered bearing will need to be _______ to help the rolling elements turn?
Preloaded
Carb bearings are used in situations that have some misalignment and axial float.
True or false
True
If you had a series 6 bearing it would be a ________?
Deep groove ball bearing
If you had a 22208 bearing it would be a __________ and have a bore of__________
Double spherical roller bearing
40 mm bore (8x5)
If you had a 6208 K RS bearing the clearance would be _______ ?
6 = single row deep groove (bearing style)
2 = light (toughness)
08 = 40mm (bore size. X5 after 03)
K = taper
RS = single rubber seal (seal code)
No bearing clearance designation means normal
A bearing ring subject to a stationary load will have a ______ to allow for creep?
Push fit
When inspecting a bearing you find discolouration, that is a sign of?
Over heating
Of a bearing being mounted has seals, you would hear it up to _______ degrees c if not sealed you heat it up to _______ degrees C
80
120
Mounting separable cylindrical bore bearings and needle bearings with no no inner ring, you will need to use _______ to aid in installation?
Guide Mandrels
Guide sleeves
Slight chamfers on shafts
To find the clearance on spherical roller bearings you can use feeler gauges.
True or false
True
Residual clearance is measured when
After it is mounted
When using the turning angle for axial drive up of tapered bore bearings with adapter sleeves, the large the shaft the larger __________
Turning angle
When using oil injection to dismount a tapered bot bearing, you should back off the retaining nut but not remove it.
True or false
True
Welding is done on bearings outer ring (when in a housing) to _________ to help in the removal of the ring.
Shrink the ring
If a bearing runs at a temperature above 55 degrees C, ___________ will occur
Rapid oxidation
If shaft runout is more than .001” or bearing seat wear exceeds .005” they need to be straightened fixed or replaced.
True or false
True
Brinelling is?
Impact denting
Imbalance and misalignment are the two main causes of vibration in bearings.
True or false
True
Fatigue in bearings will result in?
Micro cracks in or under surfaces
Pitting of surfaces
Flaking of surfaces
Improper selection of a bearing will include wrong clearances, material or type.
True or false
True
Hydrostatic lubrication uses pressure instead of speed to force the oil or film into the loaded area of the bearing.
True or false
True
One advantage of grease over oil is?
Better sealing capabilities
If you have excess grease or oil in a bearing you will get an increase in temperature of the bearing when running.
True or false
True
When removing a withdrawal sleeve, you will tighten a withdrawal nut that fastens to the sleeve and pushes against the?
Bearing inner ring
How many fixed bearings are on a line shaft? Where are they located?
1
At the drive unit
If you mounted tandem angular contact bearings backward, the load would __________ supported in the direction intended?
Not be
When replacing bearings on a reduction unit, it is important to make sure the bearing cover is properly orientated to allow proper oil drainage.
True or false
True
When installing a seal on a bearing housing, this would be called a ?
External seal
A static seal seals between?
2 stationary parts
A seal that controls leakage is call a non positive seal.
True or false
True
A lip seal uses _______ and ________ to help seal before start up and ________ after startup.
Garter spring and resilience of lip material
Lubricant and gas pressure
A V-ring seal is?
Attached to the shaft
Seals against contamination with a Flinger action
Seals agains a smooth surface on the housing
All of the above
All of the above
An external non rubbing seal that uses a tongue and groove design and a torturous path to help keep contaminants out is the _________ seal?
Labyrinth
To help pillow block bearings maintain there position, you would use key stock welded to the ends and/or slides of the pillow block, depending on the action of the load.
True or false
True
Compression packing is squeezed in a confined space by the ______?
Gland follower
Automatic packing?
Is cup packing
Has an interference fit on the cylinder walls
Has system pressure to help aid in sealing
All of the above?
All of the above
Most of the wear on shafts from compression packing is located?
At the outer two rings of packing
Radial wound packing is wrapped around the shaft until it’s OD just fits into the stuffing box?
True or false
True
Spiral wound packing is installed to shaft rotation.
True or false
True
When the lantern ring is used for cooling and sealing out harmful chemicals from the pumping medium, the lantern ring would be located under the seal water (at 10-15 psi above the pump) connection and at the?
Bottom of the stuffing box
Once the packing is installed in the stuffing box and has been seated and allowed to expand, you will _________ nuts, start pump and allow packing to leak freely, than gradually tighten gland nuts until you get a controlled leakage of________ per minute?
Finger tighten nuts
And 60 drops per minute
Mechanical seals are located there the leakage of the dangerous product cannot be tolerated.
True or false
True
Mechanical seals are made up of 4 basic components. Which of the following is not one of them?
Primary seals
Secondary seals
Shaft packing or insert mounts
Saturated
Saturat
The primary seal of a mechanical seal is aided by product pressure and?
Springs
Bellows
Lubrication between mating faces
All of the above
All of the above
If you saw spiral grooves on one of its faces it would be?
Gas lubricated seal
The primary sealing point of a mechanical seal is between the?
Rotating and the stationary seal mating faces
o-rings are used in both static and dynamic applications in mechanical seals are?
Secondary seals
A pusher seal uses _______ to help aid sealing?
Single spring
Multiple string
Bellows
Both A and B are correct
Both A and B are correct
There are two ways to drive the rotating ring on mechanical seals. They are Are?
Mechanical
And
Friction
Gland jackets come with connections for internally or externally supplied fluid for _______
Flushing
Quenching
Lubricating
Alll off above
All of the above
Bypass flushing is when________,
The pumping medium is used to remove heat
Barrier systems uses a barrier fluid admitted between the 2 seals of a double seal, the pressure is?
Higher then the pumping medium
The main difference between balanced and unbalanced seals?
Face loading is minimized on balanced
When rotational speeds exceed 4500/min, you will need a rotating seal with a?
Stationary seal
If the pumpuge comes in contact with the springs and collars and the O.D of single seals is exposed to the pumpage?
Inside mounted seal
On double mechanical seals, if you used a buffer fluid instead of a barrier fluid, it would be called a?
Tandem seal
On back to back dual seals, the 2 rotating seals face away from each other to keep out the pumping medium, also the barrier fluid:
Should be 10% higher than the stuffing box
Should be compatible with the pumping fluid
Needs to lubricate the seals
All of the above
All of the above
To help simplify mechanical seal installation, cartridge seals are used.
True or false
True
Do not lubricant the seal faces and avoid touching them.
True or false
True
When installing a mechanical seal you will first scribe a line on the shaft to indicate the seal housing face, than from the seal housing face line, measure and scribe the seal setting point, which is where the seal locking devices will be locked to the shaft to give the seal faces their required loading.
True or false
True
When inspecting and troubleshooting mechanical seals, if the wear pattern on the stationary seal is wider than the diameter and width of the rotation seal face, it is an indication that there is?
Pump misalignment
If the seal faces have chips, it is a sign of?
The liquid flashing of vapours
On a lip seal, if the lip is sealing out contamination the lip faces in or out?
Out
When dealing with gaskets and piping, it is a must to make sure that all pumps and piping are:
Locked out
Purged
Blinded
Gaskets are used to seal between 2 surfaces and need to __________ to positively seal?
Fill voids and irregularities
Be under more pressure than the sealed fluid
Handle internal and hydrostatic end force
Solid metal ring gaskets of the delta, oval and octagonal design do NOT need high bolt loading to seal.
True or false
True
Gasket thickness is critical because internal alignment and clearances can be changed.
True or false
True
The advantage of a flat ring gasket over full face gasket?
Easier removal from the flange
Spiral wound gaskets are used for high pressure and temperature applications.
True or false
True
When making gaskets, you need to know the:
O.D
I.D
Bolt hole spacing
Bolt circle diameter
When using the angle method of finding the bolt hole spacing, you divide 360 degrees by the number of spaces needed to match the bolt holes in the ________?
Flange
When making the bolt holes in the gasket, they should be?
Slightly larger than the bolt diameter
When cutting gaskets, you should use a softer material such as wood under the gasket when punching holes.
True or false
True
If you find a gasket that is breaking into pieces, it would be a sign of?
Gasket was the wrong type
Or
Installation procedure was wrong
To help transfer the flange shape to the gasket material you can use Persian blue.
True or false
True
When scraping a gasket, make sure to scrape away from you and do NOT damage the sealing surfaces.
True or false
True
When making a gasket with a hammer and housing l, avoid damaging the flange edges and bolt hole edges.
True or false
True
When torquing the bolts down on the flange, it is more efficient to take 2 or 3 passes around the bolt sequence to get the full clamping pressure required.
True or false
True
O-rings require 10% of crush for static applications.
True or false
True
Hardening sealants are:
Flexible
Ridged
All of the above
All of the above
If you see a stuffing box code that reads 4-L2-G, this means what?
4 rings of packing
Lantern ring
2 rings of packing
Gland
When cutting packing use a wooden mandrel of the same diameter as the shaft. Wrap packing around it then cut it off with a butt or diagonal cut.
True or false
When installing packing it is the utmost importance to use a s-twist to put on a rigid packing. Stagger the joints 90degrees and if stuffing is bulged use a roller gently to flatten out the packing
True or false
True
V ring packing in on a double acting cylinder should oppose each other.
True or false
True
Cup packing is considered an unbalanced packing and should have a rigid separator between the two cups when used on double acting pistons.
True or false
True
Back up Rings for O-rings help stop extrusion of the O-ring into the gap when exposed to high pressure.
True or false
True
When installing o-rings onto a shaft, protect the o-ring by adding a shaft sleeve and rolling the o-ring into place.
True or false
True
Floating packing is allowed to move in a groove and seal by the means of spring tension.
True or false
True
Lip seals are used in low pressure 2-10psi and need lubrication on the lip to seal.
True or false
True
In an emergency (for lip seals), you can _________ to accommodate to shaft wear under the lip of the seal?
Change the seal to a wider one
Reverse the seal
Install a spacer behind the seal
Install a thin sleeve over the worn part
Wipers are used to?
Clean the shaft of foreign materials
Expel foreign materials away from the seals
Allow lubricants from the equipment to remain on the rod
If the wear pattern on the mechanical seal is limited to .005” in depth you can use a course diamond impregnated plate to remove the patter using a back and forth motion.
True or false
True
When doing a final step of polishing, use a 6 micron diamond impregnated plate and figure 8 pattern when moving seals on the surface.
True or false
True
If the light band patterns on the seal surfaces have straight lines this means the surfaces are flat.
True or false
True
