# Chapter No 7 : Pumps

### Example 7.1, Page No 135

In [1]:
import math

#Variable initialization
P=2500.0            #pressure lbf/in^3
Q=3.0               #gpm flow rate
p=5.0               #Bhp  power
N=1725.0            #rpm speed

#CALCULATIONS
eo=P*Q*100.0/(1714.0*p)   # pump efficiency
To=p*5250.0/ N            # torque Input

#RESULTS
print('\n Input torque = %.3f lb-ft ' %To)

 Input torque = 15.217 lb-ft

### Example 7.2 Page No 137

In [2]:
import math

#Variable initialization
Q=52.0          #gpm flow rate
v=3.75          #in^3 positive displacement
N=3300.0        #rpm speed

#CALCULATIONS
ev=231.0*Q*100.0/(v*N)   #Volumetric efficiency

#RESULT
print('\n Volumetric efficiency = %.3f percent ' %ev)

 Volumetric efficiency = 97.067 percent

### Example 7.3, Page No 137

In [12]:
import math

#Variable initialization
eo=87.0         #percent overall efficiency
ev=94.0         #percent volumetric efficiency
p=10.0          #bhpi

#CALCULATIONS
em=eo/ev        # Mechanical efficiency
em1=em*100.0
Fhp=p*(1.0-em)

#RESULTS
print(' \n Frictional horsepower = %.3f hp ' %Fhp)
print('\n Mechanical efficiency = %.2f percent ' %em1 )


Frictional horsepower = 0.745 hp

Mechanical efficiency = 92.55 percent


### Example 7.4 Page No 150

In [4]:
import math

#Variable initialization
n=9.0           #no of cycles
N=3000.0        #rpm speed
s=0.75          #inch stroke
d=0.5           #inch diameter

#CALCULATIONS
Q=n*N*s*math.pi*d**2/(4.0*231.0)

#RESULTS
print(' Volume flow rate = %.3f gpm ' %Q)

 Volume flow rate = 17.212 gpm

### Example 7.5 Page No 162

In [2]:
import math

#Variable initialization
d=6.0           #in diameter
S=120.0         #in stroke
Q=5.0           #gpm flow rate

#CALCULATIONS
Vc=math.pi*d**2*S/(4.0*231.0)

#RESULTS
print('Minimum size of the reservoir = %.3f gpm ' %Vc)

Minimum size of the reservoir = 14.688 gpm