The pressure-compensating feature of a hydraulic pump is available only on those pump designs that are also capable of -flow delivery.

The pump shown is powered by a $20$-$\mathrm{kW}$ motor. If the pump is $82 \%$ efficient, determine the pressure rise.

Some water is placed in a sealed glass container connected to a vacuum pump (a device used to pump gases from a container), and the pump is turned on. The water appears to boil and then freezes. Explain these changes by using the phase diagram for water. What would happen to the ice if the vacuum pump was left on indefinitely?

Give the formulas and charges of the following ions:

(a) Sulfite ion

(b) Phosphate ion

( c) Zirconium(IV) ion

(d) Chromate ion

(e) Acetate ion

(f) Thiosulfate ion

A typical pump has a head that, for a given shaft rotation rate, varies with the flow rate, resulting in a pump performance curve as in Fig. P3.181. Suppose that this pump is $75$ percent efficient and is used for the system in Prob. 3.180. Compute $(a)$ the flow rate, in $\mathrm{gal} / \mathrm{min}$, and $(b)$ the horsepower needed to drive the pump.

The pump of a water distribution system is powered by a 15-kW electric motor whose efficiency is 90 percent. The water flow rate through the pump is 50 L/s. The diameters of the inlet and outlet pipes are the same, and the elevation difference across the pump is negligible. If the pressures at the inlet and outlet of the pump are measured to be 100 kPa and 300 kPa (absolute), respectively, determine the mechanical efficiency of the pump. Answer: 74.1 percent

You may have noticed that when you compress the air in a bicycle pump, the body of the pump gets warmer. Assuming the pump and the air in it comprise the system, what is the sign of w when you compress the air?

With reference to the pump data in earlier problem, if the pump is run at $1200 \mathrm{~rpm}$, Determine the discharge, head, and required power. Is the operating efficiency under these conditions the same as the pump running at $1350 \mathrm{~rpm}$ ?

What is the pressure in the hydraulic fluid?

Storage One pump can fill a tank with oil in 4 hours. A second pump can fill the same tank in 3 hours. If both pumps are used at the same time, how long will they take to fill the tank? Planning the Solution If V is the volume of the tank, what expressions represent the portion of the tank that each pump can fill in one hour? First pump: _____ Second pump: _____

A glycerin pump is powered by a 5-kW electric motor. The pressure differential between the outlet and inlet of the pump at full load is measured to be 211 kPa. If the flow rate through the pump is 18 L/s and the changes in elevation and the flow velocity across the pump are negligible, the overall efficiency of the pump is (a) 69 percent (b) 72 percent (c) 76 percent (d) 79 percent (e) 82 percent

In the figure is shown a plot of the pump net head as a function of pump volume flow rate or capacity. On the figure, label the shutoff head, the free delivery, the pump performance curve, the system curve, and the operating point.

Give the symbol, including the correct charge, for each of the following ions.

(a) barium ion

(b) titanium(IV) ion

(c) phosphate ion

(d) hydrogen carbonate ion

(e) sulfide ion

(f) perchlorate ion

(g) cobalt (II) ion

(h) sulfate ion

Water is pumped with a centrifugal pump, and measurements made on the pump indicate that for a flowrate of 240 gpm the required input power is 6 hp. For a pump efficiency of 62%, what is the actual head rise of the water being pumped?