Introduction to Boiler Designs

Vocabulary flashcards covering the history, principles, codes, categories, assembly types, and structural components of boilers.

Steam

Water in the gas phase that expands $1600$ times its volume relative to liquid water at atmospheric pressure.

Sensible Heat

Heat energy added to liquid water to raise its temperature up to its boiling point of $100\,^\circ\text{C}$ at atmospheric pressure.

Specific Heat Capacity of Fresh Water

The specific heat value for fresh water, recorded as $4.19$, making water an efficient transporter of heat energy.

Thomas Savery

The English inventor who in $1698$/$1702$ created a steam engine to pump groundwater out of deep coal mines using steam condensation to form a vacuum.

Thomas Newcomen

The engineer who in $1712$ developed the atmospheric steam engine based on Savery's principles, expanding steam power applications beyond mine pumping.

James Watt

The inventor who enhanced Newcomen's engine with a separate condenser, reducing coal usage by $75\%$ and enabling rotary motion to power factory machinery.

Haycock Boiler

An early copper shell boiler design from around $1720$ that was set inside a brick structure over an open furnace fire.

Richard Trevithick

The engineer who designed early high-pressure boilers in the early $1800\text{s}$, integrating internal furnaces, stacks, dished heads, and firetubes.

Firetube

A tube in a boiler through which hot combustion gases pass while surrounded by water, increasing heating surface area and stiffening the pressure vessel.

Stephen Wilcox

The inventor who patented the first watertube boiler in $1856$, termed the Safety boiler due to its small internal water volume and small-diameter pressure parts.

Babcock & Wilcox

The boiler company formed in $1867$ by Stephen Wilcox and George Babcock that introduced inclined straight-tube watertube boilers.

Bent Tube Watertube Boiler

A watertube boiler design using bent tubes connected to drums, maximizing heat transfer surface area and permitting placement closer to the furnace.

ASME BPVC Section I

The ASME code governing Power Boilers operating at steam pressures above $100\,\text{kPa}$ or hot water parameters above $1100\,\text{kPa}$ and/or $120\,^\circ\text{C}$.

ASME BPVC Section IV

The ASME code governing Heating Boilers operating at steam pressures up to $100\,\text{kPa}$ or hot water parameters up to $1100\,\text{kPa}$ and/or $120\,^\circ\text{C}$.

Packaged Boiler

A factory-built boiler mounted on a skid that is fully outfitted, wired, and tested prior to shipment to the installation site.

Shop-Assembled Boiler

A boiler whose major components are shop-fabricated and shop-tested before being brought together for final assembly at the facility site.

Field-Erected Boiler

A massive boiler constructed on site piece-by-piece from shop-fabricated parts using cranes and structural steel framing.

Shell

The outer cylindrical pressure vessel container of a firetube boiler.

Drum

The main cylindrical pressure vessel reservoir of a watertube boiler.

Course

An individual cylindrical ring section fabricated by rolling flat steel plate.

Longitudinal Joint

A butt-welded longitudinal seam running along the length of a rolled course.

Circumferential Joint

A perimeter weld seam connecting two adjacent courses or attaching a head to a course.

Tubesheet

A flat end plate perforated with drilled holes to hold and secure the ends of firetubes or watertubes.

Stay

A structural metal fastener installed to support unsupported flat tubesheet surfaces against internal pressure.

Flexible Staybolt

A staybolt with a threaded connection to only the inner sheet and a ball head sitting unthreaded in the outer sheet hole, permitting movement for thermal expansion.

Nozzle

A pipe connection piece welded onto a shell, drum, or header for attaching valves, piping, instrumentation, or blowdown lines.

Lagging

A protective metal outer casing sheet installed over boiler thermal insulation.

Refractory

A high-temperature ceramic material (such as bricks, boards, or castable cement) used to shield boiler structural metal from direct furnace flames.

Expanded and Flared Watertube

A watertube connection method where the tube end is expanded into a drum hole and flared outward to retain the tube under pressure without beading.

Header with Welded Tube Stubs

A boiler header equipped with short factory-welded stub tubes to allow direct field butt-welding of boiler tubes.

Curved Heads (ASME Boiler Vessels)

Formed end closures for pressure vessels—including Hemispherical, Elliptical, and Torispherical (F&D) shapes—designed to withstand high pressure better than flat heads.