Pumps Problems

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1. A whole milk homogenizer operating at a pressure of 2500 sq in. delivers 6 gal per min. If the pump efficiency is 82 percent, what size motor is required? What size motor is required if the pressure is 1500 lb per sq in.? Pipe friction may be neglected. Estimate the velocity through the homogenizing valve.

2. A 1750-rpm centrifugal pump with a 4.75-in. impeller delivers 140 gal per min against a 20-ft water head and uses 1 horsepower. What is the pump efficiency? What is the head at complete shut-off?

3. The pump of problem 2 is to operate against a 25-ft head without changing efficiency. Specify the speed, discharge rate, and power required.

4. The pump of Fig. 4.9 is connected to 40 ft of 2-in. galvanized-iron pipe. The lift is 25 ft. The system contains 2 elbows, pumps from a tank, and discharges from the pipe. What is the water pumping rate?

5. Specify a pump geometrically similar to that of Fig. 4.9 to operate at maximum efficiency at a head of 40 ft and capacity of 180 gal per min. Impeller diameter, speed, and horsepower are required.

6. Determine the efficiency of the pump of Fig. 4.14 when operating at 1150 rpm.

7. A pump delivering q1 on the system shown below must be speeded up from N1 toN2 to deliver q2. Why must N2/N1 = q2/q3?

Buy the solutions: PM @ Engineering Daily

Buy the solutions: PM @ Engineering Daily

Buy the solutions: PM @ Engineering Daily