If you have a duplex double acting...

Question 1 of 270705eccef9bbacbc34ba4d4552b

If you have a duplex double acting reciprocating pump making 190 strokes/minute, with a 4" diameter cylinder, a 8" stroke and operating with 75% volumetric efficiency, what is the capacity of this pump?

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Question 1 of 27070

🔍 Key Concepts

• Formula for capacity of a reciprocating pump in gallons per minute (gpm) based on cylinder area, stroke length, and strokes per minute • Meaning of duplex and double-acting in terms of how many displacements per stroke you actually get • How volumetric efficiency changes the theoretical capacity

💭 Think About

• First, compute the volume displaced by ONE side of ONE cylinder in one stroke, using the diameter and stroke length. Then convert cubic inches to gallons. • Figure out how many such displacements happen per minute for a duplex double-acting pump. Does each stroke move water on one side or both sides of each piston? On one or two cylinders? • After getting the theoretical gpm, apply the 75% volumetric efficiency to find the actual capacity, then compare with the choices.

✅ Before You Answer

• Confirm the correct area of the cylinder using the 4" diameter: remember to use radius, not diameter, in the area formula. • Confirm what duplex (two cylinders) and double-acting (both sides of piston pumping) do to the total number of pumping actions per stroke and per minute. • Be sure to apply the 75% volumetric efficiency AFTER calculating the theoretical capacity, not before.