MAN B&W introduced new slide fuel valves that require a new testing criterion. To meet this, Obel-P offers two new product solutions: 1) a new test pump unit that prevents damaging the slide valves by making atomization tests impossible, and 2) a lower-cost adapter unit that can be used with existing test rigs to achieve the same result. The document then provides details on the technical specifications and operating procedures for both solutions to allow for safe testing of the new slide fuel valves without risk of damage.

1. Obel-P-Products
News
New test criterion & resulting product solutions from Obel-P
The slide valve introduced by MAN B&W is now standard on all new MAN B&W engine types and
also the valves are available for retrofit purposes. The introduction of the new slide fuel valves
means that we are confronted with the new test criterion, mentioned above.
To meet this new criterion from MAN B&W, we can now offer 2 new product solutions to
shipowners, ship management companies and engine builders etc.
The atomising test has been part of the normal maintenance practice for a long time and,
therefore, a 100% safe solution is called forI
Consequently we have developed a completely new test pump unit, type VPUD 10g.0, for new
engines, where the atomisinq test cannot be eJtecuted at all.
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For vessels already in service, and therefore already equipped with a test rig, we have developed
an alternative and lower-priced solution, which can be used on any type of test rig
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not only an
Obel-P test rig! The result is the same as with a new pump unit, Le. the atomising test cannot be
executed.
MAN B&W recommend that the
new pump unit type is also used
for the conventional valves.
Conventional fuel valve
Slide fuel valve
Source: MAN B&W service letter SL02-403/UM,
June 2002
Ib Obel Pedersen AlS. Marine Division. Lerh(~ 10. Dk-2880 Bagsvard. Denmark
Phon!): +45 4498 3833. Fax:.45 4498 1125. E-mail: obel-p@obel-p.dk. Homepage: www.obel-p.dk
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2. Adapter unit type PPMI1000 for fuel valve test rigs.
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·
·
Prevent damaging your new slide valves from MAN B&W
Can be used together with existing test rigs
A safe solution - it i§..mpossible for vour crew to atomise fuel injectors with !his adaptor unit
i
connected.
The package consists of the adapter unit, a high-pressure hose and a valve. The valve is to be
connected inside the cabinet of the existing pump unit at the air side and the high-pressure hose is
to be connected at the oil out side.
The working pressure Is shown at the top
line on the display. When the opening
pressure test Is performed the result Is
frozen and shown on the bottom line on the
display.
The adapter unit is operated with a switch
button. To perform the opening pressure test
It Is turned to the right. To perform the
venting function test it is turned to the left.
'Can be used
together 't<fltlj,
any test rfg .
Ib Obel Pedersen A/S. Marine Division. LerhQ]10, Dk-2880 Bagsvard. Denmark
Phone: +45 4498 3833. Fax: +45 4498 1125. E-mail: obel-p@obel-p.dk. Homepage: www.obel-p.dk
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3. Obel-P-Products
New pump unit type VPUD 1000
·
·
This type of test rig is now standard maintenance equipment for new MAN B&W
2-stroke engines. Make sure you get one with your new buildings.
The solution for replacement of existing non-repairable test pumps.
The VPUD 1000 differs in several ways from the standard types;
VPU 1100.2 MKI or MKII, but the main feature is that the new
pump is electronically controlled.
The a(omisirrtl
test cari(lolbe
executed.
As can be seen on the picture,
the pump unit is equipped with
a digital display. It shows the
working pressure, opening
pressure and closing pressure
with an accuracy of +/- 1 bar.
Instead of the old hydraulic highpressure valve we have
installed a switch button where
the choice of test is made.
Switch it to the right and
perform the opening pressure
test, switch it to the left and
perform the venting function
test.
It is a new way of thinking and
testing but an easier way.
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Whentl1e opening
pressure .of the valve
Is reached the precise
opefJing pressure will
be s/;lown on the
display.
I
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Ib Obel Pedersen A/S. Marine Division. Lerhqj 10, Dk-2880 Bagsvard. Denmark
Ptl0ne: +45 4498 3833. Fax: ..45 4498 1125. E-mail: obel-p@obel-p.dk.Homepage: www.obel-p.dk
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4. Obel-P-Products
Technical specifications:
Adapter unit type PPMI1 000 for fuel valve test rigs:
!r!i;_;::r-1_:o-_:_-:H:_--:_:_----:_:_----ionnection
high pressure input:
Male coupling CEJN
I
lL<?on_nectio igh pressure output: High pressure hose 1 meter with female coupling CEJN
h
I
Single phase 115/230 V AC
I24 V DC
It;UPPI voltage:
Output
I
I
1!.9E:ra!iOn tperatre:_______
!1lasfit_on:____________________J
I Weight
II
................
----------------------------------
j
-100 C to 500 C
_...__ _... on...._ _...n.",
Display:
............... ..._. ..
.
............ .__........
.
__n....__.......
class 0,2
..m.__._........._.__..._....._._....._.........__.m...................._.... .......---.......
_I
3,5 kgs
........................-.............................................-.................................--.......
.
190 x 190 x 150 mm
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.................
I
Dimensions:
!I
.......-.......
_
...............
m....___......_.......
...._....._...
...
......'
...............-.-.......-....-.......
......n......
.m....,........_.......
......._..................
............................
New pump unit type VPUD 1000:
._.__.
r-~.
i
E
!
utput pressure:
Max. 1100 bar at 10 bar air input
Max. 800 bar at 7 bar air input
!
II
J ._..___......____...__..._........._....._......_.____._._..__
Airconsumption:
50 Litres per cycle at 10 bar air input
36 Litres per cycle at 7 bar and no output pressure
II
ILM~~~~l1.Z:-Li~';'j;;:(~;
ilDisPlace~ent procycle:
II
-..J~
~~;;;;;;;~t;;t~- -=--
cc (1,22 CU.IN~
Cycle fre~uency/pumping speed: JI60 cycles per min. at 7 bar air input and no output pressure
1~~~'
~~===Jf~;~~1.~Ei~~i~y~~~~.i=-
~eight
JL100 kg empty
II
ilDimensions:
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~1560 x 950 x 1525 mm
II~~;~;~I;:
--=.
~I Single Phase 115/230 V AC
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Ib Obel Pedersen AlS. Marine Division. Lerhqj 10, Dk-2880 Bagsvard. Denmark
Fax: +4544981125. [-mail: obel-p@'obel-p.dk. Homepage: wVllw.obel-p.dk
Phone: +4544983833.
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5. "PRELIMINARY"
..
Pressure testin
rocedure for slide fuel valves
This test should first be carried out after "8000 hOlJrs of service.
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Only in case of exhaust gas temperature deviation, the valves on the
unit in question should be removed between scheduled overhaul.
After 8000 hours, the atomizer should be replaced.
After 16000 hours, the complete spindle guide with atomizer should be
replaced.
Preparations
In case slide fuel valves in service has to be tested, it is of utmost
importance to clean nozzle and slid
nsure free
efore
testing.
IS is not one, ere is a risk that the valve is not considered
~operating
well. With the low capacity of the test pump, the opening
pressure can in some cases be judged to be lower than it really is!
Tighten the slide fuel valve in the test stand according to normal
procedure with the disc on the spring housing in line with the housing.
Procedure
The valve is filled up with .!1ydraulic oil by pumping with a pressure
below the closing pressure tor me non-return valve.
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When oil is leaking from the return oil pipe, the hydraulic pressure can
be increased.
It is then observed that the non-return valve is closing and the drain
from the return pipe is reduced. A small leak from the return pipe can be
observed during building up of the pressure because of the internal
leakages in the valve.
It is observed that oil not is leaking from the nozzle before rea~.
openina pressure.
.
"The opening pressure is monitored and should be Withi~O e mgher
and 380
bar. It is recommended to adjust the opening pressure to t
values within the tolerances.
The opening pressure test ~ould not be repeated many times
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6. Because of the limited capacity of the test pump. atomization test must
not be carried out as this can cause scorina between the slide and the
nozzle with conseauential stickina.
With this limited capacityof the test pump which normally is less than 5
% of the capacity of the fuel pump. the needle will not lift complete and
can cause scorina because of micro movements between nozzle and
slide.
Special conditions durina slide valve testina
a)
Based on reported strange function during testing from some vessels,
we have the following comments:
During testing, the fuel valve was brought up to the specified opening
pressure at 330
- 380 bars.
After one opening at for instance 360 bars,
the valve has continued to open at 230 bar many times.
The reason for this way of operation is that the fuel valve when it
continuously is pressurised can open at the valves closing pressure. It
will appear, as ifthe opening pressure is unstable and indicate an
opening pressure at a much lower level. However when the valve is in
service in the engine the fuel pressure is reduced to the booster
pressure after each injection, which will cause that the fuel pressure in
the valve not will find a level where the closing pressure is controlling
the opening of the valve.
This phenomenon is often seen on fuel valves, which have been taken
out directly from the engine and tested without being cleaned, but not
so often experienced when testing new valves. However it might
happen!
b)
The valve can..QPen wl!hJl high noise and a kind of atomization when
J
slowly reaching the opening pressure or in a more quiet way where the
oil is just sprayed out without noise. Both ways of opening is
considered as acceptable.
,.
c)
Because of the limited needle lift, it will in Some casp-s hp- observed thcU
oil is not spraying from all nozzle holes. T!1J~ considered to be ok.
is
.
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