INSTRUCTOR:
ROBERT A. MCLAUGHLIN
ZAILI THEO ZHAO
1
HIGH PRESSURE FITTINGS
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POWER
EQUIPMENT
LEARNING
OBJECTIVES
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A boiler and pressure vessel.
 A level 1 boiler and a critical pressure boiler.
 The various pressure fittings used on boilers.
 The types of safety valves on boilers.
 The components of a boiler gauge glass.
 The proper procedures for removing a boilers
gauge glass from service, disassembly of the
gauge, inspection and replacement and rebuild of
a typical gauge glass.

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BOILER
A steam boiler is a closed
pressure vessel in which
water is heated to
generate saturated steam.
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
The water is heated by the
gasses of combustion.
 A pressure vessel that
produces hot water heated
by the gasses of combustion
is also a boiler.

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BOILER - CLASSIFICATION
Boilers can be divided into two
pressure related categories:
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
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 boiler is


When the temperature and pressure of a boiler equals 1500 or
more.
All of the components of a level one boiler designed with a
safety factor of 5 and are tested and given serial numbers.
5
WHAT IS THE FACTOR OF
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 most
calculations
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

T St E 
p
(R)(FS)
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CRITICAL PRESSURE
Many boilers operate at
pressures 1000 to 3000
psi.
 Some operate at critical
pressure – 3206 psi and
705.08oF
Critical pressure is the
pressure at which steam
and water at the same
density.
 All critical pressure
boilers must have
separate a pump to create
circulation.
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

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EXTERNAL FITTINGS AND
CONNECTIONS



All steam and
water sections
must have
these.
The
superheater
will have
drains.
The drums and
headers will
have drains.
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 Drains
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EXTERNAL FITTINGS AND
CONNECTIONS


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 Vent
high pressure
globe valve at
high point in
the boiler
used when
filling and
emptying the
boiler.
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EXTERNAL FITTINGS AND
CONNECTIONS
connections
used for taking
boiler water
samples.
 Drains, vents,
and sampling
connections
will all have
high pressure
rated globe
valves
attached to the
connection.
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 Sample

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EXTERNAL FITTINGS AND
CONNECTIONS
stop
and check
valves

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 Feed
to manually
regulate the
flow of water
to the drum.
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EXTERNAL FITTINGS AND
CONNECTIONS
stop
valves
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 Steam
located at the
superheater
and
desuperheater
outlets.
 Used to cut
the boiler in or
out of the
main steam
line.

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EXTERNAL FITTINGS AND
CONNECTIONS
valve
two types
(huddling
chamber and
nozzle
reaction type).
 They are not
relief valves.


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 Safety
Question

What is the
difference
between the
safety and
relief valves?
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EXTERNAL FITTINGS AND
CONNECTIONS

blower
Fixed and retractable
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 Soot
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INTERNAL FITTINGS
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15
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EXTERNAL FITTINGS AND
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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
17
EXTERNAL FITTINGS AND
CONNECTIONS
and pressure
gauges
 Superheated steam flow
indicators
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 Temperature
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THE OPERATOR CONTROL THE SAFE
OPERATION OF THE BOILERS.
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GAUGE GLASS
Two independent means
of indication
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
These can consist of two
gauge glasses attached to
the drum, or a single
gauge glass, and a remote
water level indicator.
 A gauge is located so that:



the lowest visible part of the
glass is 2” above the lowest
permissible 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 of
the gauge glass
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
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GAUGE
GLASS
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
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.
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
The isolation valves are usually of the
quick closing type, capable of being closed
with ¼ 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 be
fitted 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:
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
Insure that the connections between
the drum and gauge do not become
clogged.
 To help the operator tell the level in
the glass.
 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
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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:
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
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 and
reattach the chains.

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FLAT TYPE OF GAUGE GLASS
CONSTRUCTION
2.
3.
4.
5.
6.
7.
8.
BODY
FLAT GUAGE GLASS
MICA SHEET
ASBESTOS GASKETS
ASBESTOS
CUSHIONS
COVERPLATES
STUDS
NUTS
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1.
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GAUGE GLASSES AND
TRY COCKS
Both the water column and gauge
glass must blowdown daily


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
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


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
Adjusting ring
Question

Who can
adjust the
boiler safety
setting
pressure?
29

There are two
adjustments

Adjusting ring

Nozzle ring
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
Question

How to
increase the
blowdown
pressure?
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THE WIRES FOR REMOTE
RELEASING SAFETY VALVE
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GATE VALVE RISE STEM
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GLOBE VALVE
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SWING CHECK VALVE
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BALL VALVE
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BUTTERFLY VALVE
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MARINE BOILER EXAMPLE
WHAT ARE THESE FITTINGS?

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

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
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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