Vetus DEMPMP Wet Exhaust Muffler Instruction Manual
- June 10, 2024
- vetus
Table of Contents
Installation manual
Silencer
DEMPMP
Copyright © 2021 Vetus b.v. Schiedam Holland
Introduction
The Vetus exhaust system components are especially suitable for use in water-
injected exhaust systems.
The maximum continuous operating temperature of the plastic components of the
exhaust systems is 70 degrees C (158 degrees F).
– Fit a temperature alarm to warn of excessively hot exhaust system
temperature.
– If the quantity of injected coolant water is reduced to in order to lower
back-pressure in the exhaust system, check that there is still sufficient
water injected when the engine is ticking-over. This will prevent excess
temperatures in the exhaust system.
– Excess temperature can also be the consequence of insufficient mixing of
coolant water with the exhaust gasses.
In general, good mixing is obtained by a virtually vertically installed
exhaust injection bend. Poor mixing can also occur with an engine on tick-
over; especially when the coolant water injection bend is installed virtually
horizontally. If necessary, take action. For example; by fitting a water
vortex or a water splitter in the exhaust pipe, to improve the mixing of
coolant water with the exhaust gasses.
With water-injected exhaust systems, fit a hose of suitable quality.
This hose must be reinforced, resistant to exhaust gasses, high temperatures
(100 degrees C, 212 degrees F) and oil. Easy flexibility is essential for
installation, while the hose must not collapse when heated.
Vetus exhaust hose fulfils all the above requirements.
| Engine power to * : | Hose dia.: |
|---|---|
| 18 kW (24,5 hp) | ø 40 mm (1 9/16”) |
| 22 kW (30 hp) | ø 45 mm (1 3/4”) |
| 28 kW (38 hp) | ø 51 mm (2”) |
| 39 kW (53 hp) | ø 60 mm (2 3/8”) |
| 63 kW (86 hp) | ø 76 mm (3”) |
| 89 kW (121 hp) | ø 90 mm (3 1/2”) |
| 114 kW (155 hp) | ø 102 mm (4”) |
- Based on an allowed back pressure of 0.1 bar.
**Warning
** If water enters the engine from the exhaust silencer into the exhaust system (for example: under sail when the ship rolls or pitches heavily) this will lead to irreparable damage
to the engine.
Too much water in the silencer can effect engine starting; drain off this water first. Too much water in the silencer can be also caused by repeated starting attempts while the engine refuses to start.
Installation
2.1 Installing silencer DEMPMP
The silencer can be fitted in front of, or after the goose neck. Fitting after
the goose neck gives less of a gurgling exhaust sound.
During operation, the silencer contains water. This means that the weight
increases considerably and the silencer requires additional support.
– The silencers with a hose connector diameter between ø 40 and ø 90 mm are
fitted with two handles to secure them.
– The silencers with a hose connector diameter of ø 100 mm can be secured
using the two Ty-rap®’s supplied.
2.2 Exhaust pipe
In order to ensure the proper drainage of the coolant water injected into the
exhaust pipe, the pipe must be installed with a slope downward over its whole
length from the water injection point to the exhaust silencer.
During operation, the exhaust pipe will contain water. This will increase its
weight considerably, so support the exhaust pipe properly. The exhaust pipe
from silencer to transom connection must be installed in such a way that:
– The highest point in the exhaust pipe should not be more than 150 cm (60”)
above the underside of the exhaust silencer.
– The length of the section between the exhaust silencer and the highest
point, should not exceed 300 cm (120”).
2.3 Hose connections
– To ease the fitting of the hose to the hose connector, use only water and/or
soap,
NOT grease or products containing oil.
– Fit each hose connection with 2 stainless steel 12 mm (0.5”) wide hose
clamps.
Installation examples
Exhaust systems with an exhaust silencer type LP/LSS/LSG, and silencer type
DEMPMP, goose neck type LT and a transom connection are shown on page 16 and
17.
Entry of water from the aft is almost completely prevented by the extra height
difference in the goose neck. When the engine is stopped, any water which is
still in the exhaust pipe (between the highest point in the exhaust system
and the exhaust silencer) will run back to the exhaust silencer.
To reduce the amount of this water as much as possible, the swan’s neck should
be fitted directly above the exhaust silencer, if possible (see drawings 1 and
3).
When the swan’s neck is fitted directly to the transom (drawings 2 and 4), the
maximum length of the exhaust pipe, between exhaust silencer and tee highest
point, should be taken into account.
3.1 Prevention of syphoning (drawings 3 & 4)
If the water injection point ‘C’ is below, or less than 15 cm (0.6”) above the
waterline (also when the ship heels under sail), there is a risk that when the
engine is stopped, the coolant water will enter the engine due to syphoning.
This syphoning can be prevented in two ways:
- By creating an air vent system in the coolant water hose between engine block and water injection point ‘C’, by fitting an air vent with air vent pipe, for example.
- By fitting an air vent (with valve) in the coolant water hose between the engine block and water injection point ‘C’.
Maintenance
– Check all hose connections for gas and water leaks regularly.
– Before the winter lay-up, drain the exhaust silencer.
Installation example
1 & 2: Exhaust systems with water-injection point ‘C’ 15 cm or more above the waterline
| ‘A’ | ‘B’ | ‘C’ |
|---|---|---|
| Exhaust manifold | Cooling water | Water-injection point |
3 & 4: Exhaust systems with water-injection point ‘C’ below or less than 15 cm above the waterline
Principal dimensions
Rubber exhaust hose
| I.D. | O.D. | R min. |
|---|---|---|
| ø 40 mm (1 9/16”) | ø 48 mm (1 7/8”) | 60 mm (2 3/8”) |
| ø 45 mm (1 3/4”) | ø 53 mm (2 3/32”) | 68 mm (2 11/16”) |
| ø 51 mm (2”) | ø 59 mm (2 5/16”) | 77 mm (3 1/32”) |
| ø 57 mm (2 1/4”) | ø 65 mm (2 9/16”) | 86 mm (3 3/8”) |
| ø 60 mm (2 3/8”) | ø 68 mm (2 11/16”) | 90 mm (3 9/16”) |
| ø 65 mm (2 17/32”) | ø 73 mm (2 7/8”) | 98 mm (3 7/8”) |
| ø 76 mm (3”) | ø 84 mm (3 5/16”) | 114 mm (4 1/2”) |
| ø 90 mm (3 1/2”) | ø 98 mm (3 7/8”) | 135 mm (5 5/16”) |
| ø 102 mm (4”) | ø 110 mm (4 5/16”) | 153 mm (6”) |
Warning
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