The purpose of this experiment is to study the constructional details and performance parameters of Reciprocating Pump.
The reciprocating pump is a positive displacement pump, i.e., it operates on the principle of actual displacement or pushing of liquid by a piston or plunger that executes a reciprocating motion in a closely fitted cylinder. The liquid is alternately
- Drawn from the sump and filled into suction side of the cylinder
- Led to the discharge side of the cylinder and emptied to the delivery pipe.
Fig.1 – Principal of Reciprocating Pump
The piston or plunger gets its reciprocating motion (moves backward & Forward) by means of the crank and connecting rod mechanism. In a double acting reciprocating pump suction and delivery strokes occurs simultaneously. A pump gives comparatively a more uniform discharge than the single acting pump, because of the continuity of suction and delivery strokes
PRINCIPLE OF RECIPROCATING PUMP:
Reciprocating Pump Operates on the Principle of pushing of liquid by a Piston that Executes a Reciprocating Motion in close fitting cylinder
COMPONENTSOFTHE RECIPROCATING PUMP:
- PISTON OR PLUNGER: A Piston or Plunger that reciprocate in closely fitted cylinder
- CRANKANDCONNECTING ROD: Crank and Connecting rod mechanism operated by a power source .Power source gives rotary motion to the crank. With the Help of Connecting Rod we translate Reciprocating Motion to Piston in the Cylinder.
- SUCTION PIPE: One end of suction pipe remains deep in the liquid and other end attached to the inlet of the cylinder.
- DELIVERY PIPE: One end of Delivery pipe attached with delivery part and other end at discharge point.
- SUCTION AND DELIVERY VALUE: Suction and Delivery values are provided at the suction end and delivery end respectively.This values are non-return values.
The experimental setup consists of a double acting reciprocating pump on whose discharge side a pressure gauge is fitted for measurement of the delivery head. A digital wattmeter may be connected to the motor of the pump as the motor is directly connected to the pump. A collecting tank is used to find the actual discharge through the pump.
- Note down the area of collecting tank.
- Fill the reciprocating pump with the oil up to the level marked on the pointer.
- Priming the pump before starting. Priming means taking the air present in the suction and pressure pipes.
- Before starting ensure that the pump is free to rotate.
- Flow regulating valve was adjusted to give the maximum possible discharge.
- Conditions were allowed to steady before the rate of discharge Q, discharge head & load on the motor were recorded.
- The flow rate is reduced in stages and the above procedure is repeated.
Let Discharge pressure = P m
Head = H m
Flow rate = Q m3/s
Input power = P watt
Water power (Po) = (ρgHQ) Watt
Efficiency (η) = (P/Po) x 100
Efficiency of Motor =
Area of collecting tank A =
(h ) %
1. Operate all the controls gently
2. Never allow to rise the discharge pressure above 4 kg/cm2
3. Always use clean water for experiment
4.Before starting the pump ensure that discharge valve is opened fully
- What is reciprocating pump? Describe the principal and working of reciprocating pump with neat sketch? Discuss the reason in detail.
- What is an air vessel? Explain with a neat sketch the working of air vessel in reciprocating pump.
- Give expression for discharge, work done power and slip of reciprocating pump.
- Compare the reciprocating pump with centrifugal pump. Draw theoretical indicator diagram of reciprocating pump.
- Difference between single acting and double – acting reciprocating pump?
- The cylinder bore diameter of single acting cylinder pump is 150 mm and its stroke is 300 mm. the pump runs at 50 rpm and lifts water through a height of 25 m. the delivery pipe is 22 m long and 100 mm in diameter. Find the theoretical discharge and theoretical power required to run the pump. If the actual discharge is 4.2 lit/sec. find the % slip and acceleration head at the beginning and middle of delivery stroke.
- The length and diameter of suction pipe of single acting reciprocating pump are 5m and 10m respectively the pump has plunger of diameter a 5 cm and stroke length 35 cm. the center of the pump is 3 m above the water surface in the pump. The atmosphere pressure head is running at 35rpm determine.
- Pressure head due to acceleration at the beginning of the suction stroke.
- Maximum pressure head due to acceleration.
- Pressure head in the cylinder at the beginning and at the end of the stroke.