7 семестр (Бормотов А) / 1man_bw_l23_30_chn_23_30_instruktsiya_po_ekspluatatsii_1 / MAN-BW L23-30h project-guide

Pipe description

Flange connections are as standard according to DIN 2501

General

The compressed air system on the engine contains a starting system, starting control system and safety system. Further, the system supplies air to the jet system.

The compressed air is supplied from the starting air receivers (30 bar) through a reduction station, where from compressed air at 7-9 bar is supplied to the engine.

To avoid dirt particles in the internal system, a strainer is mounted in the inlet line to the engine.

Starting System

The engine is started by means of a built-on air starter, which is a turbine motor with gear box, safety clutch and drive shaft with pinion. Further, there is a main starting valve.

Control System

The air starter is activated electrically with a pneumatic 3/2 way solenoid valve. The valve can be activated manually from the starting box on the engine, and it can be arranged for remote control, manual or automatic.

For remote activation, the starting spool is connected so that every starting signal to the starting spool goes through the safe start function, which is connected to the converter for engine RPM.

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Further, the system is equipped with an emergency starting valve which makes it possible to activate the air starter manually in case of a power failure.

Safety System

As standard the engine is equipped with a pneumatically/mechanically overspeed device, which starts to operate if the maximum permissible RPM is exceeded. This device is fitted to the end cover of the engine driven lubricating pump and is driven from the pump through a resilient coupling.

When the maximum permissible RPM is exceeded, the overspeed device will activate a pneumatically controlled stop cylinder, which will bring the fuel index to zero and stop the engine.

Pneumatic Start Sequence

When the starting valve is opened, air will be supplied to the drive shaft housing of the air starter.

The air supply will - by activating a piston - bring the drive pinion into engagement with the gear rim on the engine fly wheel.

When the pinion is fully engaged, the pilot air will flow to, and open the main starting valve, whereby air will be led to the air starter, which will start to turn the engine.

When the RPM exceeds approx. 140, at which firing has taken place, the starting valve is closed whereby the air starter is disengaged.

Optionals

Besides the standard components, the following standard optionals can be built-on:

–Main stop valve, inlet engine

Pressure transmitting

–PT 70 Compressed air inlet

Position switching, stop

–ZS75 Microswitch on flywheel

Data

For air consumption pr. start, see D 10 05 0 "List of Capacities".

Operating levels and set points, see B 19 00 0, "Operating Data and Set Points.

Design of External System

The external compressed air system should be common for both propulsion engines and GenSet engine.

Separate tanks shall only be installed in case of turbine vessels, or if the GenSets in engined vessels are installed far away from the propulsion plant.

The design of the air system for the actual plant must be according to the rules of the relevant classification society.

For the engines' internal compressed air system, please see B 14 00 0 "Internal Compressed Air System".

An oil and water separator should be mounted in the line between the compressor and the air receivers, and the separator should be equipped with automatic drain facilities.

Each engine needs only one connection for compressed air, see the internal diagram.

Installation

In order to protect the engine's starting and control equipment against condensation water the following should be observed:

-The air receiver(s) should always be installed with good drainage facilities. Receiver(s) arranged in horizontal position must be installed with a slope downwards of min. 3 - 5 deg.

-Pipes and components should always be treated with rust inhibitors.

-The starting air pipes should be mounted with a slope towards the receivers, preventing possible condensed water from running into the compressors.

-Drain valves should be mounted at lowest position of the starting air pipes.

Pipe description

*Flange connections are as standard according to DIN 2501 **See B 16 01 0 "Exhaust Gas System" and B 16 02 0

"Position of Gas outlet on Turbocharger".

General

The air intake to the turbochargers takes place direct from the engine room through the intake silencer on the turbocharger.

From the turbocharger the air is led via the charge air cooler and charge air receiver to the inlet valves of each cylinder.

The charge air cooler is a compact tube-type cooler with a large cooling surface.

The charge air receiver is integrated in the engine frame on the exhaust side.

It is recommended to blow ventilation air in the level of the top of the engine(s) close to the air inlet of the turbocharger, but not so close that sea water or vapour may be drawn-in. It is further recommended that there always should be a positive air pressure in the engine room.

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L23/30H

Water Mist Catcher

At outlet charge air cooler the charge air is led through the water mist catcher. The water mist catcher prevents condensed water (one of the major causes of cylinder wear) from entering the combustion chamber.

Turbocharger

The engine is as standard equipped with a higheffeciency MAN B&W, NR/R turbocharger of the radial type, which is located on the front end of the engine, mounted on the top plate of the charging air cooler housing.

Cleaning of Turbocharger

The turbocharger is fitted with an arrangement for water washing of the turbine side, see B 16 01 1, and water washing of the compressor side, see B 15 05 1. Soft blast cleaning on the turbine side can be fitted as optional, see B 16 01 2.

Lambda Controller

The purpose with the lambda controller is to prevent injection of more fuel in the combustion chamber than can be burned during a momentary load increase. This is carried out by controlling the relation between the fuel index and the charge air pressure.

The lambda controller has the following advantages:

–Reduction of visible smoke in case of sudden momentary load increases.

–Improved load ability.

–Less fouling of the engines exhaust gas ways.

–Limitating of fuel oil index during starting procedure.

The above states that the working conditions are improved under difficult circumstances and that the maintenance expenses for an engine, working with many and major load changes, will be reduced.

Optionals

Besides the standard components, the following standard optionals can be built-on:

Pressure alarm low

–PAL 35 Charge air, surplus air inlet

Pressure differential alarm low

–PDAL 31-62, charge air and exhaust gas

Pressure transmitting

–PT 31 Charge air, outlet from cooler

Temperature alarm high

–TAH 31 Charge air, outlet from cooler

Temperature element

–TE 31 Charge air, outlet from cooler

–TE 60 Exhaust gas, outlet cylinder

–TE 61 Exhaust gas, outlet turbocharger

–TE 62 Exhaust gas, inlet turbocharger

Temperature indicating

–TI 60 Exhaust gas, outlet cylinder

–TI 61 Exhaust gas, outlet turbocharger

–TI 62 Exhaust gas, inlet turbocharger

Data

For charge air heat dissipation and exhaust gas data, see D 10 05 0 "List of Capacities".

Set points and operating levels for temperature and pressure are stated in B 19 00 0 "Operating Data and Set Points".