Reciprocating Pumps

Estimate the percentage of work saved by fitting air vessels in a single acting reciprocating pump and also in a double acting reciprocating pump.

A single acting reciprocating pump has a plunger diameter of $250 \text{ mm}$ and stroke of $450 \text{ mm}$ and it is driven with SHM at $60 \text{ rpm}$. The length and diameter of delivery pipe are $60 \text{ m}$ and $100 \text{ mm}$ respectively. Determine the power saved in overcoming friction in the delivery pipe by fitting an air vessel on the delivery side of the pump. Assume friction factor $= 0.01$.

Describe the functions and working principle of air vessels in a reciprocating pump.

The piston of a double acting reciprocating pump has a diameter of 120 cm and a stroke of 60 cm. the pump runs at 20 rpm and discharges through a 15 cm main 76 m long (friction factor, $f = 0.03$), the vertical lift being 46 m. If no air vessel is used, determine the heads in the cylinder at the ends and middle of the stroke.

What is cavitation in pump? What are its consequences? How can cavitation be avoided?

Show that the maximum acceleration head in a reciprocating pump, without air vessel is given by the relation $H_a = \left( \frac{l}{g} \right) \times \left( \frac{A}{a} \right) \times w^2 r$, where, $l = \text{length of pipe, } A/a = \text{ratio of cylinder area to pipe area and } w = \text{angular velocity of crankshaft}$.

A double acting reciprocating pump has a bore of $175\text{ mm}$ and a stroke of $350\text{ mm}$. The suction pipe has a diameter of $150\text{ mm}$ and is fitted with an air vessel. Determine the crank angle, at which there is no flow of water to or from the vessel. Assume crank speed at $150\text{ rpm}$ and plunger has simple harmonic motion.

Show from first principle that worked saved against friction in the delivery pipe of a double-acting reciprocating pump, by fitting air vessel is $39.2$.

A single acting reciprocating pump, running at $50\text{ rpm}$ delivers $0.01\text{ m}^3\text{/s}$ of water. The diameter of the piston is $200\text{ mm}$ and stroke length $400\text{ mm}$. Determine:

The theoretical discharge of the pump.

Co-efficient of discharge.

Slip and percentage slip of the pump.

What is the difference between a hydraulic coupling and a hydraulic torque converter?

What is the specific speed of a centrifugal pump? Prove that the specific speed is $N_s = \frac{N \sqrt{Q}}{H^{3/4}}$.

A double acting reciprocating pump has a stroke of 300 mm and a piston of diameter 150 mm. The delivery and suction heads are 26m and 4m respectively including friction heads. If the pump is working at 60 rpm, find the actual power required to drive the pump with 80% efficiency.

How air vessel in reciprocating pump works to maintain a uniform discharge from the pump. Discuss with neat sketch.

A double acting reciprocating pump has a stroke of $300 \text{ mm}$ and a piston of diameter $150 \text{ mm}$. The delivery and suction heads are $26 \text{ m}$ and $4 \text{ m}$ respectively including friction heads. If the pump is working at $60 \text{ rpm}$, find power required to drive the pump with $80$ efficiency.