RECIPROCATING PUMP TEST RIG



RECIPROCATING PUMP TEST RIG

OBJECTIVE:

To study the characteristics of reciprocating pump at constant speed

INTRODUCTION:

In general, a pump may be defined, as a mechanical device which when interposed in a pipe line, converts mechanical energy supplied to it from some external source into hydraulic energy thus resulting in the flow of liquid from the lower to the higher potential/head.

Reciprocating pump has a plunger (piston) which moves to and fro in a closed cylinder. The cylinder is connected to suction and delivery pipes and fitted with non-return valves to admit the liquid in one direction only. The suction non-return valve allows the liquid only to enter the cylinder and the delivery non-return valve allows the liquid only to escape from the cylinder to the delivery line.

The piston is connected to a crank by means of connecting rod. As the crank is rotated at uniform speed by a primemover, the plunger moves to and fro thus creating continuous flow of liquid.

APPARATUS:

Reciprocating pump, collecting tank, suction gauge, delivery gauge, stop watch

SPECIFICATIONS:

PUMP : (1) Double acting, double cylinder.

(2) Dia of piston =40, stroke =45

(3) Maximum speed = 1200 RPM (max)

(4) Connected to the AC motor through

V-Belt drive and step cone pulley.

(5) Maximum horse power of the primover

Capacity required =2.0 HP

(6) Maximum head: 32 mts (3.2 kg/ cm2)

MOTOR : (1) AC Motor – 2.0 HP, 1440 RPM

Operating procedure:

All the necessary instrumentation along with its accessories are readily connected, it is just enough to follow the instructions below:

1. Fill in the sump tank with clean water.

2. Keep the delivery valve closed and suction valve open, after initially priming the pump.

3. Connect the power cable to 1 phase 220V with earth connection.

4. Switch ON the mains

5. Select the required speed using step cone pulley arrangement.

6. Close the delivery valve slightly, so that the delivery pressure is readable.

7. Operate the P.V.C valve to note down the collecting tank reading against the known time keep it open when the readings are not taken.

8. Note down the pressure gauge, vacuum gauges, and time taken for number of impulse of Energy meter.

9. Calculate the results using formulae.

PRECAUTIONS AND THINGS TO REMEMBER:

1. Do not start the pump if the voltage is less than 200v.

2. Frequently (at least once in three months) apply grease/oil to the rotating parts.

3. Initially, put clean water free from foreign materials, and change it once in three months.

4. At least every week, operate the unit for 5 min to prevent clogging of the moving parts.

5. Don’t exceed 3.2 kg/ cm2 on pressure gauge reading and never fully close the delivery valve.

CALCULATIONS:

1. Basic data/constants:

1 HP = 1/736 Watts

1 kg/ cm2 = 760mm of Hg (10 m of water)

Density of water = 1000kg/m3

Area of collecting tank = 0.3 x 0.3 m2

Energy meter constant = 1600imps/kwhr

2. Electrical power as indicated by energy meter:

Pelec = 10 x 3600 HP

EMC x t x 0.736

3. Shaft power:

Pshaft = ŋmoto X Pelec = Pelec X 0.75 =

4. Discharge rate “Q”

Q = A * R m3 / sec

1000*T

Where A = area of collecting tank 0.3 X 0.3 = 0.09 SQ-MT

R = the height of water collected in meter

T = the time taken in sec for collecting water

5. Total head ‘H’

H = 10(P)+0.001362(Pv)

or

H = 10(P) + (Pv/760)

Where P = Delivery pressure in kg/ cm2

Pv = vacuum in mm of Hg.

6. Hydraulic horse power (delivered by the pump):

HPpump = W Q H ….. KW

60X0.746

Where W = 1000kg/ m3

7. Overall efficiency:

Ŋoverall = HPpump X 100

HPshaft

TABLE OF READINGS

Speed of pump ‘N’ in RPM |Delivery Pressure

‘P’ kg/ cm2 |Vacuum ‘ Pv’ in

mm OF Hg |Total head in meter |Energy meter reading for 10 imp ‘t’ sec |Discharge height of water collected in mm of ‘h’ |Discharge taken in sec ‘t’ | | | | | | | | | |

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