VNG/VLP SERIES PRESSURE WASHER
OPERATOR’S MANUAL
43
BASIC FACTS
PRESSURE EQUIVALENTS
BASED ON 60° f
PROPANE
BUTANE
Formula
C3H8
C4H10
Vaporization Point (°F)
-43.7
31.1
Specific Gravity (Vapor)
1.522
2.006
Specific Gravity (Liquid)
0.508
0.584
Lbs. Per Gallon (Liquid)
4.23
4.87
B.T.U. Per Cubic Foot (Vapor)
2.563
3.39
B.T.U. Per Lb. (Vapor)
21.663
21/3-9
B.T.U. Per Gallon (Liquid)
91.74
1-3/93-
Cubic Feet Per Lb. (Liquid)
8.607
7/53
Cubic Feet Per Gallon (Liquid)
3.45
31/9
Octane Number
125
1
Molecular Weight
44.09
58.12
To calculate running cost:
1 cubic ft./1,000 BTU
100 cubic ft./Therm
Therm/hour
50¢/Therm
Example:
Using natural gas
400,000 BTU Machine
400 cubic feet
4 Therms/hour
4 x .50 = $2.00/hour to run
Simply stated, pressure is the force exerted by a gas or liquid attempted to escape from a container. It is useful to know how strong this
“attempt to escape” is. Pressure can be measured with a manometer or with a pressure gauge. At the lower levels, it is expresse d in
“inches of water column,” i.e. 11" w.c. Higher pressures are expressed in terms ofthe force exerted against a ssuare inch of area. For
example, 125 lbs. per square inch (125 PSI).
1" Water Column
=
50 oz./sq. in.
11" Water Column
=
6.35 oz./sq. in.
11" Water Column
=
4 lb./sq. in.
1 lb./sq. in.
=
27.71" Water Column
1 lb./sq. in.
=
2.04" Mercury
1" Mercury
=
.39 lb./sq. in.
1 Std. Atmosphere
=
14.73 lbs./sq. in.
F