Steam Boilers and Engines Questions

• Babcock and Wilcox (water-tube) boiler — orientation of water tubes: In a standard Babcock and Wilcox boiler, how are the water tubes arranged relative to the horizontal?
• Compound steam engine — effect on temperature range and cylinder condensation: State whether it is correct that compounding reduces the temperature range per cylinder and thereby reduces condensation losses.
• Definition check — simple steam engine: Is the statement correct? “If steam expands in a single cylinder and then exhausts to atmosphere or to a condenser, the engine is called a simple steam engine.”
• Boiler auxiliaries — identify the function: Does a superheater heat the feedwater using exhaust flue gases before the gases leave through the chimney?
• Boiler safety devices — high steam and low water safety valve: For the combined “high steam and low water” safety valve, under which condition(s) will it blow off steam?
• Willans’ law applicability — throttle- vs cut-off-governed engines: State whether the empirical Willans’ law holds for throttle-governed engines but not for cut-off governed engines.
• Willian's line follows the law (where b = A constant representing the shape of the Willian's line, a = Another constant i.e. no load consumption per hour, I.P. = Indicated power, and m = Steam consumption per hour)
• The water tube boilers produce steam at a __________ pressure than that of fire tube boilers.
• Boiler Surfaces — Water-Tube vs Fire-Tube (Same Tube Size) For the same outside diameter and thickness of a tube, compare the available heating surface area in a water-tube boiler with that in a fire-tube boiler. Choose the most appropriate relation.
• Steam Engine Testing — Interpreting the “Missing Quantity” Consider a steam engine heat and mass balance. The “missing quantity” (unaccounted steam/heat between admission and exhaust) is mainly attributable to which causes?
• Scotch Marine Boiler — Furnaces in a Single-Ended Unit A single-ended Scotch marine fire-tube boiler may be fitted with one to four furnaces entering from the front (uptake) end of the boiler shell. Evaluate the statement.
• Valve Gear Basics — Function of the D-Slide Valve “The function of a D-slide valve is to exhaust steam from the cylinder at the proper moment.” Decide whether this statement fully and correctly describes the valve’s purpose.
• Receiver-Type Compound Engine — Relative Crank Positions In a receiver-type compound steam engine (separate HP and LP cylinders with an intermediate receiver), the effective crank positions of HP and LP are generally considered to be:
• Condensing Steam Engines — Exhaust Pressure Relative to Atmosphere In a condensing steam engine connected to a surface or jet condenser, the cylinder pressure during the exhaust stroke is typically __________ the atmospheric pressure.
• Boiler Draught Systems — Mechanical vs Natural Draught State whether the following is true: “Mechanical draught systems (fans or blowers) can produce a higher draught than natural (chimney) draught.”
• Locomotive Boiler — Practical Upper Limit of Steam Pressure Select the nearest practical limit of maximum working steam pressure for a classic locomotive fire-tube boiler.
• Valve Motion — Is a D-Slide Valve's Displacement Simple Harmonic? In a classical eccentric-driven steam engine, the displacement of a D-slide valve with respect to crank angle is often treated as simple harmonic motion. Evaluate this statement.
• Steam Engine Terminology — Definition of Expansion Ratio In a reciprocating steam engine, the expansion ratio is defined as the ratio of which two volumes (neglecting clearance for a basic definition)?
• In boiler selection for small process plants and industrial services, the traditional Lancashire fire-tube boiler is preferred where the required working pressure and power (steam generation rate) are not extreme. For which duty level is a Lancashire boiler typically used?
• In steam boiler practice, which fitting directly controls the flow of steam from the boiler shell to the main steam line and can shut off steam completely when required?