Page 40 - Pipeline Rules of Thumb Handbook

General Information 27

How to read descriptions that show of degrees, the direction north-west would read, north 45
directions in terms of degrees degrees west.
Notice the small tract of land in Figure 6. The following
In Figure 6, the north-south line and the east-west line metes and bounds description will locate this tract: “Begin at
divide the circle into 4 equal parts with each part containing the beginning point, thence N 20 degrees west—200 feet,
90 degrees. Several different directions are shown in this thence N 75 degrees east—1,320 feet, thence S 30 degrees
diagram with the number of degrees each varies east or west east—240 feet, thence S 45 degrees west—420 feet, thence
from the north and south starting points (remember that all west—900 feet back to the point of beginning, containing so
descriptions read from the north or south). North-west is a many acres, etc.”
direction that is half-way between north and west. In terms

Figure 6. Land description in terms of degrees.

Size an air receiver for engine starting

.
.
Assume that the engine starter requires 16 standard cubic 53 5 ¥ 520 ¥ 36 624
V =
feet per second, that 10 seconds is required for starting and 144 ¥ (215 115 )
-
that you want to store enough air in the receiver for three
starts. Assume the initial pressure in the receiver is 215psia
V = 70.76cu.ft.
and the final pressure is 115psia.
Where: Assume receiver is 30≤ or 2.5 feet inside diameter. Find the
height of the receiver.
V = Receiver volume, cu. ft.
R = 53.5 for air 2
T = Temperature (assumed constant at 520°R) P ¥ ID
V = ¥ H
M = Weight of air required to start the engine based on 4
density of air = 0.0763 pounds per cu. ft.
P = Pressure, pounds/sq. ft. Where:
V = Volume to be contained in receiver, cu.ft.
Example: ID = Inside diameter of the receiver, feet
H = Height of receiver, feet
M = 16cu.ft./sec. ¥ 10sec./start ¥ 3 starts ¥ 0.0763 pounds H = 14.4 feet
per cu.ft.
= 36.624 pounds Use two receivers, each 7.5 feet high.