Diesel After-Sales Service
Service Bulletin
RL 5
25.01.89
Technical Information to all the Owners
of Sulzer RL Type Diesel Engines
Reprinted 08.04.97
Water Drain from Charge
Air Receiver and Charge
Air Temperature
Contents:
Page
INTRODUCTION
1. CHARGE AIR TEMPERATURE
2. CHARGE AIR RECEIVER
3. WATER DRAIN PIPING SYSTEM 3
28.07.07.40 Printed in Switzerland
4. STORAGE / HANDLING OF
CONDENSATE
New Sulzer Diesel Ltd
Phone: (052) 262 80 10 (24hours)
Diesel After-Sales Service
Telex: 896 659 NSDL CH
PO Box 414
Telefax: (052) 213 94 83
CH-8401 Winterthur, Switzerland
INTRODUCTION
The amount of condensate from the water separator after air cooler depends mainly on the
charge air pressure, the charge air temperature and the relative humidity and temperature of
the inlet air.
When operating in humid tropical areas the condense water quantities may be up to 0.05 0.08 kg/kWh.
Accumulation of condensate in the charge air receiver has to be avoided since water in liquid
or evaporated state, swept along by the air flow can have a negative influence on the piston
running behaviour and can increase corrosive wear to piston rings and cylinder liners.
Experience gained so far, particularly on vessels running under extreme tropical conditions,
has shown that the current condensate system does not always ensure sufficient drainage.
This Service Bulletin should be kept in a separate file in the control room. The respective pages or
tables of the Service Bulletin with modifications to the Operating Manual, Maintenance Manual or
Code Book should be copied and filed in the respective Manual or Book.
1.
CHARGE AIR TEMPERATURE
The often found practice to raise the charge air temperature after air cooler(s) in order to
avoid condensation is no longer advisable as condensation can not always be avoided with
todays highly supercharged engines.
We still recommend to operate the air coolers as follows:
- full specified cooling water flow (sea or fresh water), i.e. no throttling at part load
- sea water inlet temperature 25 - 32_C; resulting scavenge air temperature about 5 l5_C higher than cooling water inlet temperature depending on engine load
- cooling water inlet temperature for central cooling systems 25 - 36_C; resulting
scavenge air temperature about 5 - 10_C higher than cooling water inlet temperature
depending on engine load
(see also Service Instructions section 025).
As already mentioned, water contained in the scavenge air does not only have a detrimental
effect in liquid condensed form but also the vaporized or gaseous state can increase corrosive
wear to piston rings and cylinder liners. Such conditions are mainly observed when operating
in humid tropical areas and can be explained by the effect of water content in the combustion
air on the dew point temperature, as indicated in the following diagram.
1/3
Service Bulletin RL-5
_C
1
2
4
2
Typical liner wall temp.
Dew point in cylinder
during expansion stroke
with normal cooler
operation and water
separation at ISO cond.
Same at tropical cond.
3
4
load%
Same at tropical cond. but
with elevated scavenge
temp. and thus high water
content in combustion air
From the diagram it can be seen that the operating range with liner wall temperatures above
dew point can be extended when the scavenge air temperature is lowered and the absolute
water content of the scavenge air is reduced to a minimum.
2.
CHARGE AIR RECEIVER
The following improvements may be beneficial to engines in service suffering from corrosive
wear of piston rings and cylinder liners.
It is recommended to consult the engine builder case by case.
2.1 RL 56 and 66 (enclosures RL-5/1 and /2)
At the bottom fixation for the water separators, steel plates S have to be welded-in on both
sides to prevent water from by-passing the separators by the air flow.
On RL 66 type engines only, the openings D (R = 50 mm) of the plates X have to be carefully
burnt-out to enable the condensate, which may accumulate in the respective spaces, to flow
out.
2.2 RL 76 and 90 (enclosures RL-5/3 and /4)
On both sides of the bottom fixation for the water separators, steel plates E and F have to be
welded-in to prevent water from by-passing the separators by the air flow.
Additionally steel plates G have to be welded-in.
By means of the latter, in- and outlet of the water separator reach the same level.
Same as for RL 66, openings D (R = 60 mm) of the plates X have to be carefully burnt-out.
2/3
Service Bulletin RL-5
3.
WATER DRAIN PIPING SYSTEM (enclosure RL-5/5)
On mentioned enclosure the previous and the actually modified drainage system are
compared.
We recommend to install the automatic condense water drainage system which will ensure
sufficient cross-sectional area for proper drainage under all operating conditions (see as
well encl. RL-5/6).
Some automatic drain valves may have been supplied with a rather fine mesh filter.
This filter must be removed.
A small by-pass line permits a continuous limited flow of charge air and condense water.
4.
STORAGE / HANDLING OF CONDENSATE
As mentioned in the introduction considerable condense water quantities may have to be
dealt with.
In case of drainage to the bilge such quantities may exceed the capacity of the (dry) bilge
concept and frequently cause high level alarms. However, on no account should the drain
cocks be closed to prevent alarms.
Drainage to a tank for pumping over board via the oily water separator should be considered.
ENCLOSURES: as mentioned
New Sulzer Diesel Switzerland Ltd has issued this Service Bulletin with their best knowledge and
ability. However, New Sulzer Diesel Switzerland Ltd can not take any liability for any or all
information contained in this or any other Service Bulletin.
Changes of any nature to the form and or to the content of this or any other Service Bulletin as
published by New Sulzer Diesel Switzerland Ltd, are not permitted.
3/3
Service Bulletin RL-5
RL 56
A-A
88.7251
B-B
A
88.7253
88.7252
Service Bulletin Enclosure RL-5/ 1
RL 66
A-A
88.7254
725
C
B-B
88.7256
88.7252
VTR 454
VTR 564
88.7255
Service Bulletin Enclosure RL-5/ 2
RL 76
A-A
C
D
88.7261
850
C
B-B
E
F
88.7259
88.7260
VTR 564
VTR 714
88.7258
Service Bulletin Enclosure RL-5/ 3
RL 90
A-A
C
D
88.7267
845
B-B
E
F
88.7268
88.7263
VTR 564
VTR 714
88 7262
Service Bulletin Enclosure RL-5/ 4
RL 56, RL 66, RL 76 AND RL 90 ENGINES
WATER DRAIN FROM CHARGE AIR RECEIVER
PREVIOUS DESIGN
Drain cock only to be shut when
washing cooler in port
Drain cock for charge air cooler
cleaning system
Drain cock
Sight glass
Throttling disc
To portable cleaning unit,
cleaning tank or bilge
To bilge or oily-water drain tank
NEW DESIGN
Level switch for receiver drainage
(high level alarm) on special request
Automatic drain valve
1 and 2 Cocks;
only shut cock 1 when washing
cooler in port
By-pass (permanently open)
Water drain from charge air receiver
1
To bilge or oily-water drain tank
To portable cleaning unit, cleaning
tank or bilge
Wash water from charge air cooler
Service Bulletin Enclosure RL-5/ 5
AUTOMATIC DRAIN VALVE
4
1
9
7
6
8
3
5
Mesh filter to be removed if fitted
Housing upper part
Float control
Joint ring (copper or soft iron)
Float control body with rotary valve
Housing lower part
Float with lever
Control valve
Fixation screw
By-pass (connection)
Service Bulletin Enclosure RL-5/ 6
