Transcript Document
Tomislav Skračić, MA Undergraduate English Course for MARINE ENGINEERS 5th Semester
Essential reading:
SPINČIĆ, A., PRITCHARD, B.,
An English Textbook For Marine Engineers 2
., Pomorski fakultet, Rijeka 2009.
LUZER, J., SPINČIĆ, A.,
Gramatička vježbenica engleskog jezika za pomorce
, Pomorski fakultet, Rijeka 2003.
Lesson 14
WATER COOLING SYSTEM
Lesson 14 –
Water cooling system
KEY WORDS
turbo-blower contamination (n.) piston cooling gland circulating pump - turbopuhalo, turbopunjač - zagađivanje, miješanje vode s uljem - brtva, brtvilo - protočna / cirkulaciona pumpa header tank expansion tank venting (n.) water make-up engine discharge pump suction line cylinder cover exhaust valve cage - kolektor, sabirnik - ekspanzioni spremnik - odzračivanje, odušivanje, otplinjavanje - dodavanje vode - odvod, ispust iz motora - usisni vod pumpe - poklopac cilindra - skidljivo kućište ispušnog ventila supply tank drain tank - dobavni tank - ispusni tank piston distribution manifold - sabirni kolektor vode za hlađenje klipa
Lesson 14 –
Water cooling system
KEY WORDS
return (n.) inspection tank steam coil raw water inhibit (v.) scale deposit water treatment extract pump - povratak, vraćanje - kontrolni tank - parni zagrijač sa spiralnim cijevima - sekundarna rashladna voda - spriječiti, kočiti - talog kamenca, naslaga - obrada vode, pripremanje vode - pumpa kondenzata feed pump soot (n.) contrivance (n.) accessory (n.) - napojna pumpa - čađa - naprava, aparat impurity (n.) - pomoćni uređaj, pribor sleeve for soft material - košuljica, čahura, cijevasti element - nečistoća
Water cooling system
The water cooling system for a slow speed diesel engine consists of
two separate circuits
: one for cooling the cylinder jackets, cylinder heads and turboblowers; the other for piston cooling. A separate piston cooling system is used to prevent any possibility of
contamination
from piston cooling glands.
Water cooling system
The
jacket cooling system
is a closed circuit. Water passing from the engine returns through a
cooler
to the
circulating pump expansion tank
and then to the engine. A header or is placed at a sufficient height to allow the venting and connection from the engine discharge and to the pump suction line. A
water make-up heater
in the system. This has is included with by-pass to warm the engine prior to starting by circulating hot water.
Water enters at the lower end of the jackets, passing up to the cylinder covers and then to the exhaust valve cages, if these are fitted. Some water is taken from the discharge and passed through the turbo-charger turbine cooling spaces, before returning to the main discharge.
The
piston cooling system supply (or drain) tank
pump draws from the passing water to the piston
cooler
and then to the engine piston
distribution manifold
. The return from these flows by gravity to the
supply tank
. Arrangements may also be included for the return of any leakage from the glands. This must first pass through an
oil separator
for preparing the engine for sea.
and
inspection tank
. A steam coil is fitted in the piston cooling water supply tank
All
fresh water coolers
are circulated with the salt (or raw) water and have by-pass valve fitted.
Thermostatic valves
are provided to regulate the flow of either the fresh water or sea water and so control the temperature of water passing through the engine.
Fresh water pressure
should always be
greater
water to prevent any possibility of salt water entering the engine system. To reduce the corrosive action and inhibit the formation of scale deposit in the system it is usual to provide some form of than that of the salt
water treatment
.
Both jacket and piston cooling systems must have
alarms
fitted to give warning of loss in
pressure
, high or low tank
level temperature
.
or, in some cases, excess of On most engines the fresh water and sea water
pumps
are both of the centrifugal type. They may be
engine driven
motors.
or they may be
separately driven
by electric
Exercise 1 – Answer the following questions:
1.
2.
3.
4.
5.
6.
Which parts of the diesel engine require cooling?
Why is cooling necessary?
How is cooling for a slow speed diesel engine carried out?
When is a cooling system said to be of a closed type?
Why is the water cooling system fitted with a header tank?
What is the purpose of the heater?
Exercise 1 – Answer the following questions:
7.
8.
9.
10.
11.
12.
Is the water for piston cooling also drawn from the header tank?
Is the sea water the primary cooling medium in the system?
What are the thermostatic valves provided for?
Why must cooling water be adequately treated?
What alarms should the cooling system be supplied with?
What are the fresh and sea water pumps driven by?
Exercise 2 – Comprehension
I.
1.
2.
3.
Complete the sentences by choosing the correct ending: In a closed cooling system the water leaving the engine jacket is: not returned to the engine at all .
recirculated without exposure to air.
Exposed to air before being recirculated.
4.
In the cooler salt water pressure should always be lower than fresh water pressure.
equal to fresh water pressure.
greater than fresh water pressure.
6.
The secondary cooling medium used to extract heat from the primary coolant by passing through the heat exchanger is air.
fresh water.
raw water.
A centrifugal or axial flow type pump that supplies cooling water to mwchinery is known as the: extract pump.
circulating pump.
feed pump.
5.
The hard deposit that forms on inside of boilers, water pipes or on exposed ferrous metals is named: rust.
scale.
soot. The contririvance that diverts the circulation of a fluid (water, oil, or gas) as in the water cooling system where part of the hot water off the engine is returned to the inlet piping to supply the engine with water at a controlled temperature is the: regulating valve.
by-pass system.
feed piping.
Exercise 3 – Match the statements in Column A the right terms listed in Column B : with
a.
b.
c.
d.
e.
f.
A Acessory that adjust the engine cooling water to a constant operating temperature.
Sleeve of soft material used to secure a tight packing on a piston.
A unit that transfers heat from one fluid to another, as from water or oil to water or air.
A container connected to an engine cooling system, generally at the highest point, partly filled with water for venting and make up.
A device used to remove water and other impurities from lubricating and fuel oils.
A turbine driven air compressor powered by the exhaust gas.
B 1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
DRAIN TANK HEADER HEATER HEAT EXCHANGER GLAND THERMOMETER THERMOSTAT TURBO-BLOWER DISTRIBUTION MANIFOLD OIL SEPARATOR