Paragraphe 2. Le rapprochement des systèmes juridiques
A. Rapprochement et évolution des systèmes juridiques
1. Le transfert de compétence
The mid-point of the chain from 750to 1000 mm of the driver and 750 to 1000 mm of the idler must ride on the lower rail.
6.11 Spares
In the enclosed drawings spares that are recommended for stock by the user, are marked by
’S’. While ordering spares the item number and drawing number as found in the Bill of material and details furnished in the soot blower name plate must be indicated for quick supply of these items. Section 10 gives the recommended list of standard spares.
8. OPERATIONAL PROBLEMS AND MAINTENANCE
Problem Probable Cause Suggested Remedy
1.Overheating No steam flow/less steam
of the flow
lance tube
(a) Insufficient blowing Increase the blowing
pressure pressure
(b) Valve stem doesn’t move Dismantle and clean the valve stem
(c) Increase in flue gas Check the boiler temp. than the designed parameters value
(d) Absence of valve Assemble the valve
opening screw openingscrew
(e) Slipping of ‘valve open- Adjust the pull rod to ing lever‘ from ‘Tripping have proper engagement Lever’
(f) Selection of nozzle size Refer with BHEL (T) and change the nozzle head (g) Keeping the lance without Retract the lance
immedi-the blowing medium ately as soon as noticed. If lance is bent, straighten
(a) Poor quality of packing Use packing 2 Steam recommended
Leakage used for use
through
travelling (b) Further compression Use new packings carriage impossible as the packings
become solid
(c) Inadequate tightening Tighten the packings:
(Caution : Do not over-tighten the packings)
(d) Excessive wear of glands Replace the packing with new glands
(e) Scratch marks, dents or If excessive scratch marks other surface defect on are noticed, change the feed
the feed pipe pipe
3 Steam (a) Poor quality of packing Use the quality packing
leakage used recommended
through
valve stem (b) Further compression Use new packings impossible as the
pack-ings become solid
(c) Inadequate tightening Tighten the packings (Caution : Do not
over-4. Chain failure (a) Rusting of the chain and Install new chain loss of articulation
(b) Assambly of commercial Commercial chains are chains and links having low breaking load.
These chains will fail fre-quently. Install spl. quality chains only
(c) Mounting of wrong motor Check the installation of on the traverse power correct motor. Check pack and wrong setting and set the O/L relay as per of thermal overload relay recommendation
(d) Improper assembly of Assemble connector links
connector links properly
(e) Wearing of chain links Protect chains from ash
and rivets build up or change the
worn out links
5 Motor (a) Bent lance due to over- Remove and straighten the
overload heating lance tube
(b) Wrong setting of O/L Set the O/L relay as per
relay recommendation
(c) Accumulation of ash build Clean the angle tracks up over angle tracks periodically
(d) Overtightened gland Do not tighten the packing packings in the travelling too much Profuse leakage
carriage will not harm any parts
(e) Slag build up in wall sleeve Clean the sleeve or adjust or physical obstruction the SB alignment
(f) Shifting of super heater During shut-down or align reheater tubes boiler tubes so that a min.
100-150 mm. of gap is ensured
(g) Housing Damage during Rectify the housing so that
Erection the travelling carriage moves
freely
(h) Valve opening cam in Reposition the cam so that wrong direction or valve smooth engagement with opening cam placed at blowing adjustment bar is wrong position ensured
(i) Earthing of cable at any Find out the cable and
point replace the damaged cable
with a new one
(j) Rusting of terminals Replace the terminals with
which will be indicated new ones
by chattering of contacts
Problem Probable Cause Suggested Remedy
(k) Supply voltage low Ensure the availability of correct voltage
(l) Gear box jammed or no Service the gear box or fill
lubricant in the recommend lubricant
6 Limit Switch (a) Sticking of contacts due Replace the limit switch Failure to damage, or due to poor with new ones
quality contact material or due to underrating of contacts
(b) Failure of internal parts, Replace the limit switch springs, locking notches With new ones
etc.
(c) Build up of foreign Replace the broken switch particles on limit switch arm with a new one which may result in
breakage of operating arm
(d) Wrong assembly of limit Reassemble the limit switch
switch so that the overtravel is
restricted to within 50°
(e) Wrong direction of L.S. Correct the directions of
actuation the actuation
7 Valve seat (a) Gland packings over- Loose the gland packings
leakage tightened so that the valve stem
closes properly
(b) Insufficient lapping or Dismantle the valve and damage to the valve disc lap the valve stem disc with
the use of seat with the hand lapping tool(as suggested in 7501)
(c) Valve opening setscrew Adjust the valve opening pressing the valve stem setscrew so that a min.
while the travelling car- gap of 1 mm is maintained
riage is in the home position
(d) Valve stem corrosion. If the corrosion is excessive, replace the valve stem
(e) Likely small particles This can be avoided by trapped between seat and tapping the valve through
disc. a lever
Problem Probable Cause Suggested Remedy
S. COMBINATION LONG RETRACT AND WALL BLOWER
Please refer to. the T 30 MK II-E Installation Instructions for general installation and maintenance information. The specific assembly drawings for this combination retract-wall blower follow this description of the blower operation. The Assembly drawing and description of the ‘ DA ‘head furnished on this blower are also included.
Description of Operation (Refer Drg. 0-00-073-60025 and 2-00-073-70083)
Blower operation is initiated by depressing the “ Panel start - or the “ Local start push button. This creates the circuit to energize the “ CRO - relay and thus starts the rotary motor, causing the lance to rotate. This “ EXT - relay will be energized through closed centrifugal contacts on the rotary motor or through ‘ CRO ‘ contact and the limit switch LS1 thus causing the traverse motor starts, causing the lance to extend from initial position. The circuit will be locked by limit switch LS2 is tripped.
After a pre-determined travel, limit switch LS3 will be tripped energizing the latching solenoid valve SV that -controls the DA head, permitting the blowing medium to be admitted to the lance.
The blower will continue to rotate and. extend until the limit switch LS1 is momentarily tripped, breaking the circuit to “ EXT” and bringing in “ RET “ to cause the lance to retract. The circuit will be locked by 101 R contacts.
The lance will retract until limit switch LS3 is tripped energizing the timer T and R2 through closed R1 contacts. This causes the blower to stop, rotate and blow in position until timer ‘T’times out.
When timer ‘T’ times out, 101 R2 will be do-energized. The circuit will be created through closed R1 and R2 contacts to permit the blower to continue toretract. When timer T times out. energizing releasing solenoid valve SV to close the DA head and blowing will Stop. Limit switch LS2 will be stroked causing the blower to atop at its “.REST “ position.
diaphragm Operated ‘ DA’ Head
Assembly Drawing 1-00-073-60100. The ‘DA’ Head is a diaphragm operated valve which controls the flow of blowing medium to the blower. This head has a poppet type valve, which is stroked by the interaction of the diaphragm plate, spindle and a lever. The 40 square inch operator requires air loading pressure in the range of 40 to 80 psi.
When air is supplied to diaphragm it moves up racking lever No. 21 causing adjusting screw No.*
26 to stroke the head poppet valve.
There must be a back lash of at least 1- 16" between adjusting screw No. 26 and poppet valve stem. Increasing. this backlash reduces blowing pressure.
A number 60 drill blood hole is required in the tubing fitting in stalled in the diaphragm chamber while the vent port is open to atmosphere.
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10. RECOMMENDED SPARES FOR LONG RETRACTABLE SOOT BLOWER