Industrial Piping Essentials: Valves, Materials, and Testing
Understanding Industrial Piping Components
1) What is a Hamer Blind Valve and its main application? A valve like Fig. 8, drives easier and faster, ensuring total sealing.
2) What is the purpose of silicon (Si) in steel and its benefits? Which specifications mentioned in item 3 have silicon in their composition? To enhance the steel structure, making it more uniform (ASTM A106).
3) What types of tube ends are available, and what ASME standards determine their dimensions? Threaded (ASME B 1.20.1), beveled (ASME B16.25), flanged (ASME 16.5).
4) Why use galvanized pipes for a compressed air system? What type of end should these tubes have, and what should be their schedule? Threaded galvanized pipes are used because they cannot be welded without losing their treatment. Schedule 80 is recommended.
Material Selection and Application
What type of austenitic stainless steel should be used at operating temperatures around 700°C? Justify. Austenitic stainless steel stabilized with niobium titanium.
Can carbon steel be used at -45°C? If yes, what type of material specification should be used and why? Yes, normalized carbon steel (A33 Grade 6) can be used because it has a finer grain structure.
Pipe Bevels, Welding, and Flanges
1) What are the three main types of pipe bevels for welding? Describe and/or draw each. When can they be applied? Smooth, V, and J bevels.
In addition to butt welding, what other type of welding is used to connect pipes and fittings? What are its application limits? Socket welding, for diameters up to 1/2 inch.
2) What are the main types of flanges used in pipes? Briefly describe each and draw a cut of each one. Weld neck, integral, threaded, slip-on, socket weld, lap joint.
Semi-metallic and metallic gaskets are preferably used in flanges with what type of face finish? Why? Semi-metallic gaskets for smooth finish flanges, and metallic ring gaskets to fill the entire space.
Valves and Their Applications
1) What are the main applications of bud curves? What kind of service does not recommend this type of accessory? Used for changes in direction for very large diameters at a lower cost, limited to 400 pounds and diameters greater than 8 inches.
How is the casing that holds the internal fluid pressure divided? Where does the seat reside? Body and bonnet; the seat resides in the body.
2) What are valve trims? What components make up the trim in gate and globe valves? The internal mechanism, including the valve disc, seat, stem, and shutter.
3) How can valves be operated? Provide examples of valve operation. Motorized, automatic, and manual.
What is the main type of metal shutter and valve head currently used for steam services? How should they be applied to seats and plugs for low, medium, and high steam? Stellite. For low steam (up to 150), it is optional on the shutter. For medium steam (300 and 600), it is optional on the seat and mandatory on the shutter. For high steam (900 to 2500), it is mandatory on both the seat and the shutter.
Describe a fire-safe ball valve. What is its application? How many seats does it have, and what are they? What type of test should be mandatory? A valve with two seats, one resilient and one metallic, where the metallic material replaces the burned one after exposure to fire. A fire test is mandatory.
What is the main special feature of cryogenic valves (<-104°C)? Why should they have this characteristic? A long or extended bonnet to avoid freezing of the drive system.
Filters, Gaskets, and Testing
1) Describe the function of line filters, their types, and differences in application. Temporary filters are used before operation to clean lines, while permanent filters are used at equipment inlets.
What kind of service is applied to the active load-preme valve gasket? What other internal valve component can be used for this type of service? How does the active load work? Belleville spring washer to ensure the same grip initially applied.
2) Describe the four types of pressure tests applied to valves to verify their strength and tightness. Which of these tests requires a zero leak rate according to API-598? Body hydrostatic test (high and low pressure), seat hydrostatic test (high pressure), and seat leakage test (low pressure gas). The seat hydrostatic test (high pressure) requires a zero leak rate.
Traps and Valve Acquisition
1) What are traps? Describe three main types of traps. Traps remove condensate from lines. Examples include pot, float, and thermodynamic traps.
What is the minimum information required to describe and acquire a valve? Describe a globe valve with a carbon steel body, AISI-304 internals, DN 4, and class 300#.
Identifying Components and Documents
1) Identify the component/attachment with the following characteristics:
- Couch § Wedge; gate valve
- Change of direction made with cut tubes; bud curve
- Ensures 100% seal; Fig 8
- Automatic retention drive; check valve
- Trunnion type; ball valve
- Double seat against fire; fire-safe valve
- Inner and/or external ring; spiral wound gasket
- Flange end; valve
- Pressure class; flange
- Schedule; pipe
2) What are the main documents of industrial piping design? Indicate which document contains the following information:
- TAG line; flowchart
- Pipe thickness; isometric drawing
- Line size; plant layout
- Specification and description of valves and accessories; line list
- Database design (Pressure and Temperature Project); pipe inspection
- Quotas and elevations; isometric drawing