blower p.point
TRANSCRIPT
-
8/9/2019 Blower P.point
1/20
COMPRESSOR CLASSIFICATION BASED ONFLOW
R e c i p r o
R o o t s - B
v a n e T
R o t a r
P o s i t i v e d i s p
( i n t e r m i t t e n
C e n t r i f
M i x e dA x i a l
D y n a m
C o n t i n o u s
-
8/9/2019 Blower P.point
2/20
Classification of compressor.
C O M P R E S S O R
S i n g l e a
D o u b l e
S i n g l e s t a g e ,
R e c i p r o c a t i n g( p o s i t i v e d i s p l
R o o t s bV a n e T
S c r e w T
P o s i t i v e d i s p l
C e n t r i f ur a d i a l f A x i a l F
N o n - p o s i t i v e d( s t e a d y f l o
R o t a r y c o m p
-
8/9/2019 Blower P.point
3/20
ROOTS BLOWER
Rotary positive displacement blower
invented by Roots Brothers.
Pressure ratio rp=(discharge pr./suctionpr.)
Fan rp= 1 to 1.1
Blower rp= 1.1 to 3
Compressor rp>3
-
8/9/2019 Blower P.point
4/20
Principle of operation.Casing of the blower contains two lobes
mounted on parallel shafts.
Lobes are shaped as 8 or star and are gear
driven to rotate in opposite directionwithout touching the casing walls or one
another.
Due to rotation of the lobe,air dischargesthrough outlet.2/3 discharge strokes for
each revolution of each shaft.4/6 discharge
stroke per revolution of driving shaft.
-
8/9/2019 Blower P.point
5/20
Principle of operation
No internal compression or reduction of gasvolume inside the blower.
Compression will take place by back flow into the casing from the discharge line.
Pressure is not developed inside the blowerbut by the demand of the system
Water cooling is provided for the pressureabove 5000 mm wg.
-
8/9/2019 Blower P.point
6/20
Application of blower
Develop pressure
Takes air from atmosphere and transports
it the system of highpressure(e.g)Pneumatic pumping
Create vacuum
Sucks air from the system and dischargesto atmosphere. (e.g) Vacuum pump
-
8/9/2019 Blower P.point
7/20
Construction details
-
8/9/2019 Blower P.point
8/20
Accessories
Inlet air filter-to remove the dust.
Silencers- to absorb the sound
generated.
Non-return valve- to permit the flow in
one direction only.
Safety valve-to protect the machine
from excessive increase in pressure.
-
8/9/2019 Blower P.point
9/20
Safety valve
-
8/9/2019 Blower P.point
10/20
Operating instruction
Check the blower & pipe line and
ensure no foreign material.
Check the oil level.
Rotate the blower by hand to ensure
free movement.
Check the direction of motor.
Fix v-belt and check tightness.
-
8/9/2019 Blower P.point
11/20
Operating instruction
Start the blower on No-load and check
for abnormal sound.
Run the blower for 15-20 minutes onNo-load condition.
Gradually load the blower.
-
8/9/2019 Blower P.point
12/20
Operation of Blower
1.Air just entered into the right side
2.Some more air entered to the right side
3.Part of the air trapped by lower rotor and
it is ready for being swept to outlet side
4.Trapped air is being swept towards
outlet
-
8/9/2019 Blower P.point
13/20
Operation
-
8/9/2019 Blower P.point
14/20
Dismantling the blower
Remove the pulley / coupling.
Drain the oil.
Remove the end covers.Remove the gears.
Remove the bearings.
Remove the side covers / plates.Remove the rotors.
Clean all the parts.
-
8/9/2019 Blower P.point
15/20
Assembling the blower
Fix the rotor, side plate and bearings.
Set the clearance -end clearance,lobe to
lobe clearance and lobe to casingclearance.
Fix the gear wheel.
Fix the covers and fill the oil.Fix the pulley / coupling.
-
8/9/2019 Blower P.point
16/20
Clearance
1.End clearance-between casing androtor. By adjusting the thickness of
injection ring or by providing shims inbetween rotor and casing.
2. Lobe clearance-between rotors. Byadjusting the gear wheel
3. Tip clearance- inlet, outlet and centerclearance. By adjusting the side plates.
-
8/9/2019 Blower P.point
17/20
-
8/9/2019 Blower P.point
18/20
Clearance
-
8/9/2019 Blower P.point
19/20
Trouble Shooting
No air flow.
Low capacity.
Vibration.
Check the speed.
Check the direction of
rotation.
Obstruction in piping.
Check the speed.
Check the flow path.
Check alignment.
Check lobe clearance.Check bearings/gears.
-
8/9/2019 Blower P.point
20/20
Trouble Shooting.
Excessive power
consumption.
Overheating of
bearing andgears.
Check the speed.
Check the flow path for
high pressure.
Check the clearance.
Check the oil level.
Check the flow path.
Check the alignment.
Check the belt tension,
slip.