# Chapter10-Pneumatic and Hydraulic Drives¶

## Ex1-pg195¶

In [1]:
import math

print('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-10.1 Page No.195\n');

P=100.;                ##[lb/in^2] Hydraulic pressure
F=450.;                ##[lb] Extension force
Fr=400.;               ##[lb] Retraction force

A=F/P;                ##[in^2] Cross section area
D=math.sqrt(4.*A/math.pi);      ##[in] Bore of cylinder

print'%s %.2f %s '%('\n The bore of cylinder is ',D,' in.');

##Use 2.5in bore cylinder

Dm=2.5;               ##[in] Bore of cylinder
Dr=1.;                 ##[in] Diameter of rod
A2=math.pi*Dm**2/4.-math.pi*Dr**2/4.; ##[in^2]
F2=P*A2;              ##[lb] Force

if F2>=Fr:
print'%s %.2f %s '%('\n The diameter of rod is ',Dr,' in.');
else:
print'%s %.2f %s '%('\n This would not meet requirement');

##This would meet requirement

Ab=math.pi*Dm**2/4.;        ##[in^2] Cross section area
##Note-In the book V=180.7 is used instead of V=180.64158
d=20.;                ##[in] stroke
V=Ab*d+A2*d;         ##[in^3] Volume per cycle
t=2.;                 ##[s] Cycle time
FR=V/t;              ##[in^3/s] Flowrate

FR=FR*7.48*60/1728.;  ##[gal/min] Flowrate

print'%s %.2f %s '%('\n Flow rate required is ',FR,' gal/min.');

MACHINE DESIGN
Timothy H. Wentzell, P.E.
EXAMPLE-10.1 Page No.195

The bore of cylinder is  2.39  in.

The diameter of rod is  1.00  in.

Flow rate required is  23.46  gal/min.


## Ex2-pg198¶

In [2]:
import math

print('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-10.2 Page No.198\n');

Pa=100.;              ##[lb/in^2] Air pressure
Da=4.;                ##[in] Diameter
Aa=math.pi*Da**2/4.;       ##[in^2] Cross section area

F1=Pa*Aa;            ##[lb]
Do=1.;                ##[in]
Ao=math.pi*Do**2/4.;       ##[in]
Po=F1/Ao;            ##[lb/in^2]

print'%s %.2f %s '%('\n The oil pressure is ',Po,' lb/in^2.');

D2o=3.;               ##[in]
A2o=math.pi*D2o**2/4.;     ##[in^2]
F2=Po*A2o;

print'%s %.2f %s '%('\n Force F on piston rod is ',F2,' lb.');

D=1.;                 ##[in]
d=4.;                 ##[in]
A=math.pi*D**2/4.;         ##[in^2]

V=A*d;               ##[in^3]

print'%s %.2f %s '%('\n The volume in 1-inch cylinder for the 4-inch travel is ',V,' in^3.');

A3=math.pi*3**2/4.;        ##[in^2]
l3=V/A3;             ##[in]

print'%s %.2f %s '%('\n Travel for 3-inch cylinder is ',l3,' in.');

MACHINE DESIGN
Timothy H. Wentzell, P.E.
EXAMPLE-10.2 Page No.198

The oil pressure is  1600.00  lb/in^2.

Force F on piston rod is  11309.73  lb.

The volume in 1-inch cylinder for the 4-inch travel is  3.14  in^3.

Travel for 3-inch cylinder is  0.44  in.