Presentation on theme: "POWER EQUIPMENT INSTRUCTOR: ROBERT A. MCLAUGHLIN ZAILI THEO ZHAO"— Presentation transcript:
1 POWER EQUIPMENT INSTRUCTOR: ROBERT A. MCLAUGHLIN ZAILI THEO ZHAO 12:36POWER EQUIPMENT INSTRUCTOR: ROBERT A. MCLAUGHLIN ZAILI THEO ZHAOHIGH PRESSURE FITTINGSWEEK 13
2 Learning Objectives A boiler and pressure vessel. 12:36A 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.
3 Boiler12:36A 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 combustion is also a boiler.
4 Boiler - classification 12:36Boilers can be divided into two pressure related categories:Low pressure – boilers operating at 15 psi and below.High pressure – boilers operating above 15 psi.
5 Boilers can also be categorized into Level ratings. 12:36Boilers can also be categorized into Level ratings.A Level 1 boiler isWhen 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.
6 WHAT IS THE FACTOR OF SAFETY? 12:36Ultimate 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
7 Critical pressure Many boilers operate at pressures 1000 to 3000 psi. 12:36Many boilers operate at pressures 1000 to psi.Some operate at critical pressure – 3206 psi and oFCritical 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.
8 External fittings and connections 12:36DrainsAll steam and water sections must have these.The superheater will have drains.The drums and headers will have drains.
9 External fittings and connections 12:36Venthigh pressure globe valve at high point in the boilerused when filling and emptying the boiler.
10 External fittings and connections 12:36Sample connectionsused for taking boiler water samples.Drains, vents, and sampling connections will all have high pressure rated globe valves attached to the connection.
11 External fittings and connections 12:36Feed stop and check valvesto manually regulate the flow of water to the drum.
12 External fittings and connections 12:36Steam stop valveslocated at the superheater and desuperheater outlets.Used to cut the boiler in or out of the main steam line.
13 External fittings and connections 12:36Safety valvetwo types (huddling chamber and nozzle reaction type).They are not relief valves.QuestionWhat is the difference between the safety and relief valves?
14 External fittings and connections 12:36Soot blowerFixed and retractable
17 External fittings and connections 12:36Water 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.
18 External fittings and connections 12:36Temperature and pressure gaugesSuperheated steam flow indicators
19 the operator control the safe operation of the boilers. 12:36
20 Gauge Glass Two independent means of indication 12:36Two independent means of indicationThese 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 levelthe upper most visible part of the glass is located 2” below the upper most
21 Gauge Glass12:36Boilers operating at pressures below 250 psi can be fitted with tubular type gauge glassesAbove 250psi, flat type gauge glasses are required.Isolation valves are required on each leg of the gauge glass
22 Gauge Glass12:36There 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
23 Gauge Glass12:36Every 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 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.
24 Gauge Glass12:36Each 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 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.
25 Gauge Glass12:36Leaks above the actual water level will indicate higher than normal levels.Leaks below the actual level will indicate lower than normal levels.
26 Gauge Glass To blow a glass down for normal maintenance: 12:36To blow a glass down for normal maintenance:Disconnect the pull chainsClose 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.
27 Flat type of Gauge glass construction 12:36BODYFLAT GUAGE GLASSMICA SHEETASBESTOS GASKETSASBESTOS CUSHIONSCOVERPLATESSTUDSNUTS
28 Gauge Glasses and Try Cocks 12:36Both the water column and gauge glass must blowdown dailyPrevent sludge accumulations from blocking linesObserve 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 slowlyThis is an indication of clogging up.The situation must be corrected as quickly as possible, even if the coiler has to be shut down.
29 There is one adjustment on the muddling chamber type safety valve 12:36There is one adjustment on the muddling chamber type safety valveAdjusting ringQuestionWho can adjust the boiler safety setting pressure?
30 There are two adjustments 12:36There are two adjustmentsAdjusting ringNozzle ringQuestionHow to increase the blowdown pressure?
31 The wires for remote releasing safety valve 12:36