Page 597 - Air and Gas Drilling Manual

flow rate of compressed air through the motor of approximately 400 gal/min. Using
a nozzle inside diameter of 10/32 inches (for all three nozzles) yields a drill bit speed
of approximately 200 rpm. The inside diameter of the nozzles, D n, is
d n 0 3125 inches Chapter 11: Specialized Drilling Equipment 11-35
.
d n
D n
12
.
D 0 0260 ft
n

Figure 11-12: Horsepower and torque rotor shaft output versus pressure drop across a
Baker Oil Tools Model Mach 1, 6 3/4 inch outside diameter positive displacement motor.
For a volumetric flow rate of 400 gal/min (courtesy of Baker Oil Tools).
The total cross-sectional area of flow through the drill bit nozzles, A n, is

0 0260)
A 3 (. 2
n
4
.
A n 0 00160 ft 2