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84 Cards in this Set
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- Back
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Welded & Flanged Piping by JCW |
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State the formula for calculating C-F for: 3) 45 degree short radius butt weld elbow |
1) NPS x 1 1/2 2) NPS x 5/8 3) NPS x 1 |
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Do all unions require a gasket to ensure a proper seal? If no, which ones don't require it? |
No, those that are butt welded, fusion socket welded |
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What does (5" by 4" by 3" butt weld fitting) describe to you about the fitting? |
Its a tee, with a 5" opening and 4" opening on the horizontal, with a 3" branch. The method of joining is butt welding |
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What would you use a wraparound to do and for which process? |
You would use it to mark around a pipe to be cut by an oxy/fuel torch |
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When butt welding, what is the typical gap? |
1/8" 37.5 degrees After the 2nd tack |
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What's another name for a Lap Joint Flange? |
Van Stone Flange |
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What's the primary disadvantage of a reducing flange? |
Turbulent flow due to pipe size changes |
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What does RFWNF mean? How high is its face raised? |
Raised Face Weld Neck Flange |
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For corrosive, high temperature or high pressure applications, which sealing surface is best? |
Ring-type Joint face (RTJ) |
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What pressure rating are cast iron flanges available in? |
#125 & #250 |
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Where would you refer to find the size and number of studs needed for bolting flanges together? |
Your IPT handbook, pg 227 onwards |
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Regarding gaskets, there are 3 basic flange face types. What are they? |
Full face Flat ring Metalic ring |
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Which gasket flange is normally softer than the flange material itself? Why? |
Metallic ring So it can compress and form a good seal |
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A ring joint can only be seperated by? |
An axial pull
A Flange seperator |
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Which method uses a soft face hammer and ball pein hammer to make your own gaskets? |
Trace & Tap |
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What's the maximum temperate for asbestos compound gasket? |
500C 260C |
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Why are ring cut gaskets preferred over full face flange gaskets? |
Less torque needed for a good seal |
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What should always be applied to a gasket for easier removal when servicing at a later date? |
Non-stick compound |
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How should flange be stored? |
Hung in a cool, dry location |
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Which pattern should flange bolted be tightened? |
In a star pattern. i.e. Tighten the north & south bolt first, then east & west bolts. Continue pattern while moving clockwise around the flange. |
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Each fitting has markings on it. What are the 5 markings? |
Company/Trade name Schedule number Lab. control number |
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There are 8 flange types. List them |
Weld Neck Slip-On Screwed/Threaded Reducing Orifice |
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How does a weld neck flange differ from a slip-on flange? |
Weld neck flange is the same pipe size as the pipe it joins to and is butt welded together Slip on flange is slightly larger than the pipe it joins to, slipping on. It has an inner and outer weld |
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How does a screwed flange differ from a slip-on flange? |
Both are slightly larger than the pipe they join to. Screwed flange has threads and is used to join to the pipe. Slip-on has to be welded on |
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How does a socket weld differ from a slip-on flange? Which type of system is socket weld most common in? |
A socket weld has an extra recessed stopping ring within the flange, which the incoming pipe butts against. Only an outer weld is needed.
For high-pressure systems 4" and smaller |
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How do you order reducing flanges? |
You state the centre size first, then the OD of the master flange i.e. 6" by 16" |
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How are orifice flange different from the rest of the flanges? |
They come in sets and have tappings built in, which allows for installation of metering devices. |
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How are Lap Joint flanges different from the rest? |
It consists of a stub end pipe and a flange slightly larger with a gradual curve where the flange meets the stub end. The stub end is welded to the pipe |
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What is a blind flange used for? |
Its a flange with no hole so its used to shut off or blank off piping? |
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What's the main use of a spectacle blind. |
So you can quickly visually check if the pipe is operational or not |
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What are the 5 flange faces |
Raised face Flat-faced Ring-type joint faced Male & Female sets Tongue & Groove sets |
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For a raised face (RF) flange, what is the range of height that the face is raised inside the bolt circle?
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1/16" to 1/4" |
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For flat-faced (FF) flanges, it is only used with 1 gasket, which is it? |
Full-face gasket |
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Which is the defining characteristic of a ring-type joint face (RTJ) flange? |
It is like a RF flange with a concentric groove in the flange face, where a metal ring is used as its gasket |
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What is the defining characteristic of a male & female set of flanges? |
It has an unusually high raised face with a corresponding depression in the female flange. The gasket is similar to the RF flange gasket |
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What is the defining characteristic of a tongue & groove set of flanges? |
Basically, this is a RTJ flange with its matching partner. |
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Flat ring gaskets are usually 1/16" to 1/8" thick, 1/2" to 3" wide. Narrow gaskets are preferred over wide gaskets, but not too narrow. Explain why this is |
Narrow gaskets require less bolt torque to be leakproof versus wider gaskets. However, too narrow and the gasket will be crushed |
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What is the main benefit of serrated gaskets? |
With the concentric or V grooves reducing the surface contact to a few narrow lines, less bolt torque is needed for a good leakproof joint. |
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Laminated gaskets used to be filled with asbestos fillers. Now which material is used? |
Teflon Can be used for higher temperates, up to 400C |
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There are 3 types of corrugated gaskets. What are they? |
All metal |
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Ring joint gaskets, specially used for RJT flanges, comes in two styles. What are they? |
Octagonal & Oval |
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Spiral wound gaskets is a varient of laminated gaskets. How is it different and what is the purpose of spiral wound gaskets? |
Rather that a layer of filler shealthed by a metal layer, spiral wound gaskets have alternating plies of V-shaped metal and filler. |
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Synthetic rubber can be used for gaskets. What is the max pressure & temperature allowed? |
150 psi & 120C / 250F |
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Asbestos and Teflon are used as fillers for high temperate applications. What is the maximum temperate for each filler? |
Asbestos - 500C / 750F Teflon - 260C / 400F |
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Metalic ring gaskets are used for RTJ flanges and comes in 3 types. What are they? |
D - soft iron S304/S316/S410 - stainless steel |
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Flexatallic is a tradename for what type of gasket? Describe how this gasket is made up? |
Has a solid outer ring with spiral-wound metal strip (usually steel or stainless steel) with asbestos or teflon filler. |
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What's the formula for finding out the wrench size for finish nuts? |
Finish nuts = bolt diameter x 1.5 Machine bolts / 2H bolts = bolt diameter x 1.5 + 1/8" |
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Graphite or another non-sticking compound is applied to flanges for easy removal later on. What is used to thin graphite? |
Water or water with glycerine |
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Why are ring-cut gaskets preferred over full face gaskets? |
Less bolt torque is needed for a leakproof seal |
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When using full-flange gaskets, what must you do to prevent the gasket from pinching the bolt upon tightening it? |
The gasket holes must be slightly larger than the bolts, to allow for the gasket to bulge slightly and yet not pinch the bolts |
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What tool should you use to ensure you apply even torque to all bolts if you're using hand wrenches? |
A torque wrench |
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For best joint performance on high temperate service, what must you remember to do the next day and the following week? |
Check to see if you need to hot-tighten or re-torque the bolts |
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Which gas is produced during the air liquefaction process? |
Oxygen |
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Name the safety device used on oxygen cylinders and which pressure does it trigger at |
Metal rupture disc that has a bursting pressure of 22,000kPa or 3200psi |
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Explain why fuel gas cylinders have left-hand threads while other non-fuel cylinders have right hand threads? |
This is a safety feature that ensures the equipment is not interchangable (hoses, regulators, etc) |
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Explain why an acetylene cylinder is filled with a porous material |
The porous material prevents a large volume of free acetylene gas from accumulating under high pressure (which would go BOOM), thereby keeping acetylene stable |
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State 2 safety precautions used to prevent acetone loss |
Keep the cylinders vertical Do not exceed the draw limit (or you'll draw up acetone along with the acetylene) |
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In order to protect the regulator gauges, you should..? |
Release the adjusting screw before you open the cylinder valve (otherwise, all that high pressure from the cylinder would have no where to go and burst the gauges) |
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Why are the cylinder valves "cracked" before the regulators are attached? |
To remove dust/dirt from the cylinder valve |
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How should you check for leaks on oxyfuel equipment? |
Apply a suitable leak detection fluid |
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What does the term "creep" mean as it relates to welding equipment regulators? |
Creep occurs when the valuve on the high-pressure or working side of the regulator does not seat properly and gas is allowed to eak past, raising its pressure above normal |
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What is the colour of an acetylene hose? Oxygen hose? |
Acetylene - Red Oxygen - Green |
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What two tools would you use to preperly clean a dirty tip? |
Tip cleaner or Tip drill |
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What is the difference between backfire and flashback? What causes both of them? |
Backfire occurs in the tip, due to too little gas, dirt or other obstructions of gas and "pops" as gas ignites itside the tip. |
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What do you have to do when changing welding tip size? |
You have to rebalance gas pressures due to a different orifice size on the tips |
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Why should the acetylene torch valve always be set to work above the smoke range? |
This ensures that adequate gas flow is maintained and reduces the possibility of backfires and burnbacks |
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In the event of a fire while using acetylene, what is the process taken for fire fighting |
Stop the flow of oxygen first, then acetylene, then put the fire out |
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What is the chemical symbol for acetylene? What is its explosive range in air? |
C2H2 |
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Acetylene is consider "unstable" and its "critical point" is to be avoid when storing it. What is its critical point at 21C? |
193kPa (28psi) |
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Oxygen cylinders must be stored in seamless hot drawn vessels but acetylene can be stored in welded vessels. Why? |
Oxygen cylinders operate at far higher pressures than acetylene and need to be hot-drawn to be stronger |
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What used to be the filler in older acetylene cylinders? What was its main drawback? |
A mixture of charcoal, shredded asbestos, portland cement and balsa wood. It was very heavy and would crush, leaving a void in the vessel. |
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Acetone makes up what % of volume in an acetylene cylinder? How does this relate to "stamped weight?" |
40%
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What is a flashback arrestor and how does it work? |
Flashback arrestors prevent flames from travelling from the torch handle backwards to the regulator. |
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What are the two value types on an acetylene cylinder? How far can the valves be opened? |
Wheel-type & Key-type |
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What is the main safety feature built into acetylene cylinder and what is its trigger point? |
Fusible metal plugs, set to melt at 100C / 212F, allowing for controlled release of gas |
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What is the main purpose of a regulator and what are its 3 main working parts? |
To reduce source pressure and maintain a constant delivery pressure, regardless of changes in source pressure |
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Oxyacetylene hoses comes in 3 sizes, what are they? |
3/16" / 5mm 1/4" / 6.4mm 3/8" / 10mm |
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List the process for setting up an oxyacetylene outfit |
1. Hand/gloves clean, cylinder secured 2. Remove cylinder caps, valves not pointing at each other, crack to clear dirt 3. Attach pressure regulators (fittings must be compartible), then attach flashback arrestors & hose 4. Release regulator adjusting screws, then open oxygen valve fully, acetylene no more than 1.5 turns |
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List the process for lighting and balancing an oxyacetylene outfit |
1. Turn in pressure adjusting screw on acetylene regulator to get fuel flowing. 4. Adjust oxygen regulator till neutral flame at tip |
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What is a carbonizing flame, with respect to acetylene torches? |
A flame rich in acetylene, and is a lower temperature than a neutral flame.
3X flame (feather is twice as long as cone) |
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Uses of a carbonizing flame? |
Fusion welding of alloy steels / mild steel using low alloy, high strength filler rods Hard surfacing applications |
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What temperate does a neutral acetylene flame operate at? |
30900C / 5600F Fusion welding mild steel, cast iron Braze welding of steels |
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Max temperature of an oxidising acetylene flame? |
3470C / 6300F Fusion welding of brass & bronze Brazing of copper & galvanized iron Braze welding of cast iron & malleable iron |
