726 



THE. BELL SYSTEM TECHNICAL JOURNAL, MAY 1957 



Q 



Z 



o 

 u 



LU 



in 



LU 



a 

 ui 



UJ 



I 

 u 



z 



o 



(D 



D 

 U 



5 



o 



16 

 14 



12 



10 



8 



6 



-I -6 



-8 



-10 



-12 



■14 

 -16 



-10 -8-6-4-2 2 4 6 



VALVE POSITION IN LINEAR MILS 



8 10 



Fig. 12 — Flow characteristics of J-7 valve. 



between one-third and one-half the supply pressure. The exact point is 

 dependent on the magnitude of the supply pressure as well as the co- 

 efficients in the equation. 



The valve will be wide open, an opening of 0.009 inch, when maximum 

 power is produced. In this situation, (1) becomes: 



p = IO9 + 7.6g2 (2) 



Useful output power at the load is the product of the flow rate and the 

 pressure exerted on the piston. 



where 



W = {P - p)q 



W = Output power 



P = Suppl}^ pressure, psi 



(3) 



