A pressure gauge reads 500 psi. If it was pumping oil with a specific gravity (S.G.) of 0.75, what would the feet of head be?

To determine the feet of head from a gauge pressure reading and the specific gravity of the fluid, you can use the following formula:

[ \text{Feet of Head} = \frac{\text{Pressure (psi)} \times 2.31}{\text{Specific Gravity (S.G.)}} ]

In this case, the pressure gauge reads 500 psi, and the specific gravity of the oil is 0.75. Plugging these values into the formula gives:

[ \text{Feet of Head} = \frac{500 \times 2.31}{0.75} ]

Calculating this step by step:

1. Multiply 500 psi by 2.31:

[ 500 \times 2.31 = 1155 ]

2. Divide this result by the specific gravity of 0.75:

[ \frac{1155}{0.75} = 1540 ]

This calculation leads to a result of 1540 feet of head. Therefore, the choice corresponding to this calculation is indeed the correct answer. Understanding this relationship is important for millwrights, as it allows them to convert pressure readings into a head measurement, which is crucial for system design