T2ASCO LLC
technical traini
servrces
&
@2009-2016 TJ Young / T2ASCO LLC
com
913-634-4967
Routine Baghouse lnspection ltems
Operational lssues
o
o
o
o
o
o
o
o
o
o
o
o
o
o
-
"Best Operatino Practices"
Preheating Baghouse on Startup?
Automatic Damper Control Equipped / Used?
Small TPH Rate Changes Being Made? (NR if dust silo)
Leaving Dust in Hopper on Shutdown? (NR if dust silo)
Dust Free-Flowing in Hopper? (inspect visual dirty side)
Seal on Primary Working Properly?
Differential Pressure Acceptable? (2" to 6"and stable)
All Bags Cleaning Properly? (inspect visual dirty & clean side)
Pressure in header 90-110 psi? (pulse jet only)
Header recharges 2 seconds or less? (pulse jet only)
Water being drained from header I receiver? (pulse jet only)
Temperature lnto Baghouse Acceptable? (220"F or more)
Temperature lnto Fan Acceptable? (185"F or more)
Temperature Drop Across Baghouse Acceptable? (50'or less)
Mechanical lssues
-
"Maintenance ltems"
o
o
o
o
o
Top Doors Well Sealed? (check audible during operation)
o
o
o
o
o
o
o
o
Blow-pipe holes orig. dia. / not elongated? (pulse jet only)
Top Door Corrosion? (visualcheck)
Tube Sheet Corrosion / Wear? (visual check +/or sonic thickness test)
Clean Air Plenum Corrosion lWear? (visual check +/or sonic thickness test)
Pulse valves all operating efficiently? (pulse jet only)
lNote: consider preventive rebuild every 5 years this item)
Turrets rotating / parking properly ? (reverse atmosphere only) (visual check)
Collection and take-away hanger bearings & llange bearings OK? (visualcheck)
Fan Drive Alignment / Vibration Acceptable? (visual check)
Fan Bearing Temperatures Acceptable? (200'F or less)
Fan Lubrication Levels Acceptable? (visual check)
Airlock / Tip Valve Condition / Wear (if equipped)? (check rotor clearances)
Dust Blower Condition / Wear (if equipped)? (check pressure relieve valve / oil)
Licensed for use by AEM
-
World of Asphalt 2016
T2ASCO LLC
technical trainin & adviso
@2009-2016 TJ Young / T2ASCO LLC
www.hotmixproduction.com 913-634-4967
servrces com
Baghouse lnspection & Bag Change-Out Guidelines
There are difference of opinions in the sequence of performing baghouse inspection for the purpose of
identifying "bad bags" and changing bags. I find it most effective to start with the dirty side of the unit and
then perform clean air inspection and fluorescent powder tests after finding bad bags via the dirty side.
1.
Do internal baghouse inspection periodically and whenever there is dust in the stack.
2. Note that failure to change bags will also eventually
damage the fan wheel, causing outof-balance condition to the fan and damage the fan bearings.
3. lnspect bags from dirty side first. (Replace bags with holes or bags with dust in bottom.)
4. Always clean off the tubesheet after changing bags. (Helps you locate bad bags later.)
5. After changing bags, run one week, then look for "dust trailers" in the clean air plenum.
(A bag with a hole will be at end of the "dust trail".)
6.
7.
8.
lf "dust trail" is not clearly visible, use testing powder and black light to find bad bag.
lf stack is emitting dust ONLY when the baghouse pulses, and if powder test does not
clearly point to bad bags, consider that bags have dust migrated into the felt. Send
bags off for a permeability test and microscopic analysis to help verify this.
When changing large quantities of bags, realize the new bags will see most of the air
flow, and the bag life of the new bags will be reduced.
(Bag life is best when all the bags are changed in the baghouse.)
(Changing all the bags needing to be done quickly, not stretched out for weeks.)
9.
Always verify pulse pressure in the header is at least 80 psi, and the header re-charges
in 2 seconds or less. (lf reverse-air baghouse, make sure turrets are properly operating)
(90-1 10 psi typically works best based on my experience, but the lower the pulse
pressure that can be used to maintain an acceptable pressure drop, the longer
the bag life and the less "dust migration" into the bags.)
(lt is best to install a gauge directly on the header to verify header pressure.)
10. Drain water from the header periodically.
(Water reduces header volume and may be blown into bag with pulse valve.)
1
1. Adjust pulse duration so that valves have sharp noise
/ "crack" to them when they pulse.
(Pulse valves must not stay open too long. Blow-pipe should jump. You should
not hear air rushing down through the blow pipe into the bags. You will hear air
recharging the header from the compressor, however.)
12.Yerify all the dust is leaving the hopper periodically.
(There should not be any "mounds" of dust in the hopper and dust should be half
full in the screws during plant operation. This can be checked on a "hot stop".)
Licensed for use by AEM
-
World of Asphalt 2016