Capítulo 4: Resultado creativo de la investigación: que incluye una reseña sobre el libro- libro-arte como una de las alternativas plásticas de construcción de imagen, algunos referentes
1 UNA MIRADA PANORÁMICA . CONFESIONES
1.6 SOBRE LA REPRESENTACIÓN, INTERPRETACIÓN Y APROPIACIÓN SIMBÓLICA
overhaul
6. Piston support:
Remove the piston from the cylinder and place it on the piston support. See Proce-dure 9021.2. For evaluation of the rings, see Volume I, Chapter 707.
Note!
It is recommended to replace all the pis-ton rings whenever a pispis-ton is removed from the engine.
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MAN B&W Diesel Checking
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Before dismantling the piston rings, mea-sure the free ring gap of all the piston rings.
For dismantling the piston rings, see Proce-dure 9021.3.
8. Radial ring width:
Measure the radial width of the rings. Note down the results See Volume I, Operation, Chapter 707.
9. Ring grooves:
Clean the ring grooves and check them for burn marks or other deformation.
Measure the ring grooves with a calliper gauge, see Data D0210 and D0211.
Clearance in piston ring grooves:
The maximum vertical height in a worn ring groove must not exceed the value stated in Data. The groove is also worn out if there is no chromium layer.
If the ring grooves are worn out, the piston crown must be reconditioned, contact MAN B&W Diesel A/S for advice.
MAN B&W Diesel
10. Piston top template:
Check that the piston top template is per-manently marked with the piston top centre diameter D0248.
Check that the centre area C has been marked off, and write the maximum per-missible burnaway rate on the template.
See data D0247.
Mark the outer part of the template R for ring area, and write the maximum permis-sible burnaway rate for the ring shaped area. See data D0249.
11. Piston crown top:
Clean the piston crown and check the burnaway by means of the template.
For maximum permissible burn away on the piston top centre area, see Data D0247.
For the ring shaped area, see Data D0249.
Check the burnaway on the whole circum-ference of the piston crown top.
If the burnaway exceeds the values given in Data, contact MAN B&W for advice.
Note down the results for later reference.
11.
10.
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MAN B&W Diesel Dismantling
M90201280D01
Preparations in the crankcase 1. Access:
Open the crankcase door to the cylinder concerned.
Turn the crosshead down far enough to give access to the piston rod stuffi ng box and the piston rod/crosshead connection.
1.
MAN B&W Diesel Dismantling
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2. Telescopic pipe:
Loosen and remove the screws which tight-en the telescopic pipe to the btight-end. Remove one screw from the telescopic stuffi ng box housing and mount the special tool for suspending the telescopic pipe or use the thread in the telescopic pipe stuffi ng box housing.
Turn the crosshead to TDC. Suspend the telescopic pipe by means of the tool.
Turn the crosshead downward and remove the distance pipe from the bend.
2.
Note!
When a piston is dismantled, never turn the engine without fi rst dismantling the telescopic pipe from the crosshead.
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MAN B&W Diesel Dismantling
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D1302
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3. Stuffi ng box:
Release the stuffi ng box by removing the innermost screws from the stuffi ng box fl ange.
On engine models where the drain pipe is connected directly to the stuffi ng box:
Disconnect the stuffi ng box drain pipe.
4. Loosen the piston rodcrosshead connec-tion:
Loosen and remove the hydraulic nuts, see
Data. See Procedure 9131. 4.
3.
Note!
Do NOT remove the outermost screws from the fl ange.
MAN B&W Diesel Dismantling
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5. Stuffi ng box distance pieces:
Mount the two distance pieces on the pis-ton rod foot to protect the lower scraper ring and to guide the stuffi ng box.
Preparations on the cylinder top 6. Cylinder cover:
Remove the cylinder cover. See Procedure 9011.2.
Make a scratch mark in liner and pis-ton cleaning ring to ensure correct remounting. Remove the piston cleaning ring.
Carefully remove any wear ridges at the top of the cylinder liner. See Procedure 9031.3.
5.
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6.
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MAN B&W Diesel Dismantling
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D0225
7. Piston lifting tool:
Turn the piston to TDC. The top of the pis-ton is now free of the cylinder liner.
Clean the lifting groove of the piston crown and mount the lifting tool.
Limited lifting high:
If the engine is not equipped with long dis-tance pieces, remove one or two cylinder cover studs, using a stud setter.
7.
Note!
Make sure to mount the lifting tool cor-rectly, so that the claws of the lifting tool enter the lifting grooves of the piston crown.
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D0220
Piston lift
8. Lift the piston out of the cylinder liner and guide the piston rod foot through the stuff-ing box fl ange.
If the engine is equipped with long distance pieces for the stuffi ng box, the piston rod foot can pass between two cylinder cover studs.
Place the two halves of the support around one of the openings in the platform. Low-er the piston rod foot and stuffi ng box through the opening in the platform. Secure the two support halves with screws and lower the piston on the support. Check the piston is resting on the piston rod fl ange.
8.
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9. Protect the crosshead bearing:
Place a cover over the opening for the pis-ton rod stuffi ng box at the bottom of the cylinder unit.
Turn the crosshead down far enough to permit mounting of the protective rubber cover on the crosshead bearing cap. The protective rubber cover is found on tool panel 904.
The covers must remain in place to protect the crosshead bearing journal from impuri-ties until the piston is remounted.
Clean, measure and recondition the cylin-der liner. See Procedure 9031.
9.
MAN B&W Diesel
1. Piston support:
Place the piston in the support and remove the piston lifting tool.
See Procedure 9021.2.
Clean the piston top and the piston rings.
Check the free ring gap and the burnoff on the piston top. See Procedure 9021.1.
Remove the stuffi ng box. See Procedure 9022.3.
2. Piston ring dismantling:
Take off the piston rings by means of the ring expanders. If the engine is equipped with two ring expanders, the short ring ex-pander is for the uppermost ring.
First remove the uppermost ring, then ring No. two, three and four.
Clean and inspect the rings and the ring grooves. See Procedure 9021.1.
3. Piston crown dismantling:
Loosen and remove the hydraulic nuts be-tween the rod and the piston crown. See Data.
For operation of hydraulic tools, see Proce-dure 9131.
Lift the piston crown and skirt clear of the piston rod.
2.
1.
3.
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MAN B&W Diesel Overhaul
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D0206
D0224
D0222
4. Piston rod and cooling pipe:
Remove the screws from the cooling oil pipe fl ange.
Mount the eye bolts and lift out the cooling oil pipe.
Clean and inspect the cooling oil pipe and the piston rod, then remount the cooling oil pipe, see Data.
Check that the surfaces of the Oring groove is clean and smooth.
Mount a new Oring on the piston rod fl ange.
5. Piston crown turning:
Unhook the crane from the piston lifting tool, and connect the lifting tool and the crane hook by means of a wire rope. Lift up the piston crown.
Fit two eyebolts in the piston skirt and a wire rope between the bolts as shown in the sketch.
Install a tackle in a suitable place with suf-fi cient space below for the piston crown.
Attach the tackle to the wire rope on the piston skirt and carefully turn the piston crown upside down.
Use both cranes if the engine room is equipped with two cranes.
Land the piston lifting tool and the piston crown on a suffi cient support of wood pieces. Loosen the piston lifting tool and lift the piston crown clear of the tool.
5.
4.
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MAN B&W Diesel Overhaul
6. Piston crown dismantling and cleaning:
Place the piston crown with skirt on a wooden support as shown.
Remove the locking wire and the screws in the skirt. If necessary, use two disman-tling screws to pull the skirt off the piston crown. Mount two eye bolts in the skirt. Lift the skirt and land it on a couple of planks.
Discard the sealing ring on the piston skirt.
Thoroughly clean and inspect all parts of the crown and skirt. If coke deposits are found in the cooling spaces of the pis-ton crown, the coke deposits should be washed out with Carbon Remover or a sim-ilar cleaning fl uid. When all coke deposits have been dissolved, clean and inspect the piston crown again.
If the piston crown is renewed, remove the piston crown studs using a stud setter.
7. Piston crown assembly:
Mount the piston crown studs in a new or overhauled piston crown, lubricate the threads on the studs with molybdenum di-sulphide (MoS2).
Tighten the studs to the specifi ed torque using a stud setter, see Data D0204.
Mount a new Oring on the piston skirt, check that the surfaces of the Oring groove is clean and smooth, coat the ring with lubricating oil before mounting.
Mount the piston skirt on the piston crown.
Tighten the screws to the specifi ed torque, see Data D0205. Lock the screws with locking wire. See Procedure 9137.
7.
6.
Note!
Coke deposits reduce the heat transfer from the piston crown to the cooling oil. The deposits must be removed as a routine procedure when a piston is over-hauled.
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MAN B&W Diesel Overhaul
4
8. Piston crown and skirt mounting:
Lubricate the Oring on the piston rod fl ange with lubricating oil.
Land the overhauled piston crown and skirt on the piston rod.
Mount and tighten the hydraulic nuts on the piston crown studs.
When tightening the hydraulic nuts follow the tightening sequence. All the nuts must be tightened twice to full tightening pres-sure, see Data.
Sealing ring and pressure test
According to current class rules, the piston must be pressure tested hydraulically. It is possible to carry out a test of the sealing rings with compressed air before fi lling the piston with oil. The sealing ring test can also be carried out when the piston is rest-ing in the support tool.
9. Sealing ring test:
Mount the pressuretesting tool on the piston rod foot. Connect compressed air to the testing tool and fi ll the piston to 45 bar. Close the valve on the testing tool and remove the air connection. The piston must now hold the pressure for minimum 30 minutes.
Spray a little soap water on to the surface joints between piston rod/crown/skirt and around the hydraulic nuts to detect leaks.
Dry off all soap water.
9.
8.
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oil
D0201
10. Pressure test:
For this test, the piston must be turned upside down (see next step to turn a com-plete piston).
Fill the piston and piston rod with lubricat-ing oil. Mount the pressuretestlubricat-ing tool on the piston rod foot. Pressuretest the piston at the pressure stated on the Data Sheet. Check the contact surfaces of the piston and the sealing rings for tightness.
Check that there are no cracks in the pis-ton crown.
Turn the piston upside up and drain out the piston oil.
10.
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MAN B&W Diesel Overhaul
11.
Note!
During the lift, follow with the crane to keep the crane positioned vertically above the lifting point. The stuffi ng box must be removed.
11. Piston turning:
Lift the piston with the normal lifting tool.
Lower the piston rod foot until it is close to the platform. Land the foot on a wooden block.
Lower the piston crown to the platform and land it on a wooden block in such a way that it is possible to remove the lifting tool.
Mount an eyebolt in the side of the lifting tool, hook on the crane and remove the lift-ing tool from the piston crown.
Attach the lifting bracket to the bottom of the piston rod foot. Hook the crane on to the lifting bracket. Lift the piston rod foot clear of the wooden block. Keep lifting until the piston rod is in a vertical position.
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12. Piston completion:
Fit the new piston rings (alternately
righthand and lefthand cuts, with the ring gaps staggered 180° and with the TOP mark upwards), using the ring expander.
When mounting the piston rings, use the ring expanders to prevent unintended de-formation of the rings.
Do not expand the rings more than neces-sary. The uppermost ring (CPRring) must be mounted with the short ring expander.
Mount the piston rod stuffi ng box.
See Procedure 9022.3.
12.
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TOP A
B
C
D
A
B
C
D
902-1.4
MAN B&W Diesel Mounting
Preparation of piston
1. Check the piston rings and piston crown in accordance with Procedure 9021.1, if not already done.
Mount the lifting tool on the piston crown.
See Data D0225.
2. Stuffi ng box position:
Ensure that the stuffi ng box is correctly po-sitioned over the distance pieces mounted on the piston rod foot. Both the holes for the fl ange and the drain hole for the drain pipe must be positioned correctly.
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D0225
2.
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MAN B&W Diesel Mounting
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45°
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Preparation of cylinder liner 3. Mount the guide ring:
Mount the guide ring in the top of the cyl-inder liner. The cut outs for the lifting tool must be turned to foreaft position.
4. Stuffi ng box cover:
Remove the cover from the piston rod stuffi ng box opening in the bottom of the cylinder unit.
Clean the stuffi ng box fl ange.
5. Crosshead position:
Turn the crosshead to a position 45° from TDC (crank web pointing towards exhaust side).
3.
5.
4.
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MAN B&W Diesel Mounting
Mounting of piston
6. Coat the Orings of the stuffi ng box and the piston rod with oil. Coat the piston rings and cylinder liner with cylinder lubri-cating oil.
Lower the piston into the cylinder liner – while guiding the piston rod foot through the cutout in the stuffi ng box fl ange – until the piston rings are inside the liner.
7. Protective cover:
Remove the protective rubber cover from the crosshead.
8. Crosshead alignment:
Turn the crosshead almost to TDC.
If necessary, mount the hydraulic nuts on the studs and screw down until the nuts are fl ush with the top of the studs.
Turn the crosshead upwards until the pis-ton rod foot lands on the nuts, thereby turning the crosshead until the face is par-allel to the piston rod foot.
Lower the crosshead just enough to enable removal of the nuts. Turn the crosshead upwards until the piston rod lands on the crosshead. When mounting the piston on the crosshead, make sure that the piston rod foot does not damage the threads of the studs. Ensure that the guide ring in the crosshead fi ts correctly in the centre hole of the piston rod.
Unscrew the lifting tool and remove the lift-ing tool and the guide rlift-ing for piston rlift-ings.
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D0220
6.
7.
8.
MAN B&W Diesel
Tighten the piston rod stuffi ng box by means of the screws through the inner holes in the stuffi ng box fl ange. For Data, see Procedure 9022.
On engine models where the drain pipe is connected directly to the stuffi ng box:
• Mount the stuffi ng box drain pipe.
Remove the distance pieces from the piston rod foot.
10. Tightening of the piston rodcrosshead connection:
Mount and tighten the piston rod nuts with the hydraulic jacks. See Data.
See Procedure 9131.
11. Telescopic pipe:
Place the distance pipe on the bend for the telescopic pipe.
Turn up towards TDC until the telescopic pipe is landed on the distance pipe.
Remove the suspending tool and mount the screws and tighten the telescopic pipe to the bend.
For Data, see Procedure 9042.
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D0105
12.
13.
14.
12. Piston cleaning ring:
Mount the piston cleaning ring in accor-dance with the scratch mark. If the PCring is damaged (broken or cracked), it must be replaced by another ring.
See Procedure 9031.
13. Cylinder cover studs:
If the cylinder cover studs have been re-moved, remount them. Carefully clean the surfaces around the base of the studs and check the Orings on the studs.
Mount the cylinder cover studs with the stud setter. Screw the stud down to con-tact and half a revolution back.
14. Cylinder cover:
Land the cylinder cover on the liner and check the distance that the stud is protrud-ing from the cylinder cover. If necessary, adjust the distance D0105 by turning the stud.
Tighten the cylinder cover nuts and mount the necessary pipes.
See Procedure 9011.4.
15. Runningin:
Smear the piston rod with molybdenum di-sulphide, and turn the crankshaft a couple of revolutions.
At the fi rst opportunity, start the engine and keep it running for about 15 minutes at a speed corresponding to “Dead Slow”
Ahead.
Then stop the engine and inspect the pis-ton rod and stuffi ng box.
MAN B&W Diesel
SAFETY PRECAUTIONS
Data
D02-26 Stuffing box flange, outer screws tightening torque 180 Nm
D02-27 Stuffing box flange, inner screws tightening torque 200 Nm
D02-28 Stuffing box halves, tightening torque 80 Nm
D02-29 Uppermost rings, ring-end clearance 4x6 mm
D02-30 Lowermost rings, ring-end clearance 3x3 mm
D02-34 Sealing ring springs new, free length 831 mm
D02-38 Scraper ring springs new, free length 782 mm
D02-44 Stuffing box complete 190 kg
D02-45 Stuffing box half 65 kg
D02-50 Stuffing box halves fitted bolts, tightening torque 80 Nm
Data
102-2
X
For detailed sketch, see 900-2
Stopped engine
Shut off starting air supply – At starting air receiver Block the main starting valve
Shut off starting air distributor/distributing system supply Shut off safety air supply – Not ME engines
Shut off control air supply
Shut off air supply to exhaust valve – Only with stopped lubricating oil pumps Engage turning gear
Shut off cooling water Shut off fuel oil
Stop lubricating oil supply Lock the turbocharger rotors
Ref. Description Value Unit
X
MAN B&W Diesel
The task-specific tools used in this procedure are shown on the plates at the end of this chapter or in the chapters indicated by the first three digits in the plate number, e.g. P90951 refers to chapter 909.
Data
P90251 109 Mounting tool for stuffing box spring P90251 122 Worktable for stuffing box
P90451 120 Rubber cover for crosshead
Plate Item No. Description
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1. After the piston rod stuffing box has been 1.
dismantled, check the following clearances:
See Procedure 902-2.2.
Uppermost scraper ring and sealing rings Clearance at ring ends (scraper ring).
Total clearance (scraper ring). (D02-29) Clearance at ring ends (sealing rings).
Total clearance (sealing rings). (D02-29) Lowermost scraper rings
Clearance at ring ends.
Total clearance. (D02-30)
The ring clearances stated in Data apply to new rings.
As a general guide, it is recommended – depending on the overhauling intervals and one’s own experience – to replace sealing rings and scraper rings when the specified clearance values D02-29 and D02-30 have been halved.
2. Garter springs:
Generally, it is recommended to renew the springs when the sealing rings and scraper rings are renewed.
The springs can be checked as follows:
Place the springs on the table, measure Lo (free length), and compare with Data. If a spring is extended more than 8% from the
Place the springs on the table, measure Lo (free length), and compare with Data. If a spring is extended more than 8% from the