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POWEREQUIPMENT
INSTRUCTOR:
ROBERT A. MCLAUGHLIN
ZAILI THEO ZHAO
HIGH PRESSURE FITTINGS
WEEK 13
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LEARNING
OBJECTIVES
A boiler and pressure vessel.
A level 1 boilerand a critical pressure boiler.
The various pressure fittings used on boilers.
The types of safety valves on boilers.
The components of a boilergauge glass.
The proper procedures for removing a boilersgauge glass from service, disassembly of thegauge, inspection and replacement and rebuild of atypical gauge glass.
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BOILER
A steam boiler is a closed
pressure vessel in which
water is heated to generate
saturated steam.
The water is heated by the
gasses of combustion.
A pressure vessel that
produces hot water heated
by the gasses of combustionis also a boiler.
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BOILER - CLASSIFICATION
Boilers can be divided into two
pressure related categories:
Low pressure boilers operating
at 15 psi and below.
High pressure boilers operating
above 15 psi.
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Boilers can also be categorized into Level ratings. A Level 1 boileris
When the temperature and pressure of a boiler equals 1500 ormore.
All of the components of a level one boiler designed with a safetyfactor of 5 and are tested and given serial numbers.
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SAFETY?
Ultimate strength divided by
allowable working stress or
bursting pressure divided
by safe working pressure.
It can vary between four
and seven depending on
age, type of construction,
and condition.
Use five for mostcalculations
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(R)(FS)
EtTSp
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CRITICALPRESSURE
Many boilers operate atpressures 1000 to 3000 psi.
Some operate at criticalpressure 3206 psi and
705.08oFCritical pressure is the
pressure at which steamand water at the samedensity.
All critical pressure boilersmust have separate apump to create circulation.
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Drains
All steam and
water sections
must havethese.
The
superheater will
have drains.
The drums and
headers will
have drains.
EXTERNALFITTINGSAND
CONNECTIONS08:38
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Vent
high pressure
globe valve at
high point in
the boiler
used when
filling and
emptying the
boiler.
EXTERNALFITTINGSAND
CONNECTIONS08:38
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EXTERNALFITTINGSAND
CONNECTIONS
Sampleconnections used for taking
boiler water
samples. Drains, vents,
and samplingconnections willall have highpressure ratedglobe valvesattached to theconnection.
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EXTERNALFITTINGSAND
CONNECTIONS
Feed stop
and check
valves
to manuallyregulate the
flow of water
to the drum.
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EXTERNALFITTINGSAND
CONNECTIONS
Steam stop
valves
located at the
superheater
and
desuperheater
outlets.
Used to cut the
boiler in or out
of the main
steam line.
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EXTERNALFITTINGSAND
CONNECTIONS
Safety valve two types
(huddlingchamber andnozzle reactiontype).
They are notrelief valves.
Question What is the
differencebetween thesafety andrelief valves?
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EXTERNALFITTINGSAND
CONNECTIONS
Soot blower
Fixed and retractable
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INTERNALFITTINGS08:38
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EXTERNALFITTINGSAND
CONNECTIONS
Water gage glass attached
directly to the drum, they
allow the operator to see the
water level in the drum.
All boilers operating over 400
psi are required to have two
independent means of
determining water level.
One will be a gauge glass
attached directly to the steam
drum; one will be a remote
water level indicator.
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EXTERNALFITTINGSAND
CONNECTIONS
Temperature and pressure
gauges
Superheated steam flow
indicators
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THEOPERATORCONTROLTHESAFE
OPERATIONOFTHEBOILERS.08:38
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GAUGE GLASS
Two independent means
of indication
These can consist of two
gauge glasses attached to
the drum, or a single gaugeglass, and a remote water
level indicator.
A gauge is located so that:
the lowest visible part of the
glass is 2 above the lowestpermissible drum water level
the upper most visible part of
the glass is located 2 below the
upper most
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GAUGE GLASS
Boilers operating at
pressures below 250 psi
can be fitted with tubular
type gauge glasses
Above 250psi, flat type
gauge glasses are
required.
Isolation valves are
required on each leg ofthe gauge glass
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GAUGE
GLASS
There are high pressure glass type
indicators that can be used instead
of flat gauge glasses,
for example, bicolor gauge glasses.
Figure gauge glasses work on the
principle of light refraction
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GAUGE GLASS
Every gauge glass will have valves to
isolate the gauge from the drum pressure
for maintenance and emergency situations.
The isolation valves are usually of the quick
closing type, capable of being closed with
turn of the handles. The handles will be connected by chain
pulls so that an operator can pull on the
chain and close both valves at the same
time from a remote location.
The bottom isolation valve will always befitted with a ball check device to prevent hot
water from flowing through a broken gauge
glass.
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GAUGE GLASS
Each gauge glass assemble will be
fitted with a blowdown connection to:
Insure that the connections between the
drum and gauge do not become clogged.
To help the operator tell the level in theglass.
If you are in doubt of the level in the
glass, blow the glass down (open the
gauge drain valve).
If you blow a glass down, and you see the
water level go up through the glass, then
the drum level is high.
If no level appears, then the level is high.
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GAUGE GLASS
Leaks above the actual
water level will indicate
higher than normal
levels.
Leaks below the actual
level will indicate lower
than normal levels.
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GAUGE GLASS
To blow a glass down for normal
maintenance:
Disconnect the pull chains
Close the top valve and open the drain
valve (blowdown valve). Let it drain for a
few seconds.
Open the top isolation valve and close
the bottom isolation valve. Leave the
drain open for a few more seconds.
Close the drain valve.
Open the bottom isolation valve andreattach the chains.
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FLATTYPEOF GAUGEGLASS
CONSTRUCTION
1. BODY
2. FLAT GUAGE GLASS
3. MICA SHEET
4. ASBESTOS GASKETS
5. ASBESTOS CUSHIONS
6. COVERPLATES
7. STUDS
8. NUTS
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GAUGE GLASSESAND
TRY COCKS
Both the water column and gauge
glass must blowdown daily
Prevent sludge accumulations from
blocking lines
Observe the level when it is blown. When the valve is opened, the water
should drop out of the glass rapidly.
When the valve is closed, it should
return rapidly to its previous level.
If the glass water drains slowly This is an indication of clogging up.
The situation must be corrected as
quickly as possible, even if the coiler
has to be shut down.
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There is one
adjustment on
the muddling
chamber type
safety valve
Adjusting ring
Question
Who can adjustthe boiler
safety setting
pressure?
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There are two
adjustments
Adjusting ring
Nozzle ring
Question
How to
increase the
blowdown
pressure?
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GATEVALVE RISESTEM08:38
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GLOBEVALVE08:38
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SWINGCHECKVALVE08:38
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BALLVALVE08:38
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BUTTERFLYVALVE08:38
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MARINEBOILEREXAMPLE
WHATARETHESEFITTINGS?
1 - Gauge Glass or Water Column
2 - Main Steam, Safety, Auxilary Steam
Valves
3 - Pressure Gauge
4 - Surface Blow
5 - Skin Valve (through ship's side)
6 - Bottom Blow
7 - Hydrokineter (to increase water
circulation)
8 Furnaces
9 - Fire-Tube bundles
10 - Main Feed Valve
11 - Auxiliary Feed Valve
12 - Deep Blue sea
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THANK YOU
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