Steam Engine Specifications/Work Diagram Construction

=Construction of a Work Diagram=



Refer to fig. 7 in "Steam Engines'

Procedure
 * 1) Determine the initial pressure, ratio of expansion, and percent of clearance.
 * 2) Draw lines OX and OY at right angles.
 * 3) Make OR the clearance displacement percent.
 * 4) Make RX the length of the stroke
 * 5) Draw RA perp. at the clearance displacement length to represent 3-8% (med. speed engine) of the total displacement.
 * 6) Draw AK at 0.98 of the boiler pressure
 * 7) Draw KX at the stroke length.
 * 8) Draw LH at 14.7 psi for atmospheric pressure.
 * 9) Locate cutoff point B for expansion ratio (1/8, 1/4, etc. of stroke len)
 * 10) Divide BK into equal distances (a,b,c, etc)..
 * 11) Connect them to point O
 * 12) Extend horizontals from the points where diagonals meet with line BP.
 * 13) Extend verticals down from (a,b,c, etc)
 * 14) Connect these points to form the expansion curve.
 * 15) Back pressue curve at FD about 2psi above atmospheric
 * 16) Compression curve at DE, rounded up to start of cycle.

Area of actual diagram is slightly smaller than the theoretical: