what is the gpm of a piston pimp with an 8 inch diameter?

Question

a piston pump with a 6 inch stroke makes 50 strokes per minute. What's the gpm if the diameter is 8 inches?

Answer 1

Volume of the cylinder = pi * r^2 * stroke
3.141 * 4^2 * 6 = 301 cubic inches = 1.3 gallons (according to my conversion program)

1.3 gallons * 50 strokes/minute = 65 gallons/minute.

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Answer 2

It depends on the type of pump we are talking about. Single acting or double acting:

In single acting pumps the first stroke is the inlet stroke and the second stroke is the discharge stroke therefore:
25 strokes of delivery / min * 1.31gal per delivery stroke=32.75 gal / min

Now if the pump is double acting; It delivers flow on each stroke. The one side of the piston is the inlet while the other side of the piston is the discharge during the first stroke. The second stroke the opposite. Then the above answeres of 65gpm (US) would be the pump delivery.

Answer 3

Volume of pump cylinder = π x r x r x h
= 3.14 x 4 x 4 x 6 = 301.4 in³
301.4 x 50 = 15,072 in³/min.
1ft³ = 1728in³ = 7.5 US gal. of water.
15,072 ÷ 1728 = 8.72 ft³
8.72 x 7.5 = 65.4 gal/min. (US).

(8.72 x 6.24gal/min UK = 54.4 gal/min UK).

(If it's a liquid other than water, multiply the above gal/min figures by the S.G. of the liquid).
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