high pressur fittings - week 13

7/28/2019 High Pressur Fittings - Week 13

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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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high pressur fittings - week 13

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