Construction and Performance Testing of the Hydraulic Ram Pump

GMSARN International Conference on Sustainable Development: Issues and Prospects for the GMS

12-14 Nov. 2008

Construction and Performance Testing of the Hydraulic Ram Pump

Phyo Min Than

Abstract— The hydraulic ram pump or hydram is an automatic water lifting device that uses the energy in the flowing water such as spring, stream or river to pump part of the water to a high above that of the source. With a continuous flow of water a hydram operates continuously with no external energy source. Hydram have only two moving parts, these are impulse valve and delivery valve. They are very simple to operate and maintain. It can be used for water supply to countryside and remote areas, domestic and irrigation. The main purpose of hydram is to reduce the use of nonrenewable energy. In this paper contains Introduction, History of the hydram, operation of the hudram, Design of the hydram, construction and performance testing of hydram and a complete set of detail drawings for manufacturing o f 9.144m (Delivery head) hydram. Keywords—Drive head, delivery head, driving flow rate, pumping flow rate.

1.

INTRODUCTION

The hydraulic ram pump can be used with great effectiveness in mountain villages which are located at a higher elevation than their source of water. The hydram pump used the power of falling water to pump a small portion of that water uphill. It requires absolutely no fuel or electricity, only water pressure. The pump was developed about 200 years ago, and the beauty of the hydram lies in its simplicity. There are only two moving parts which are lubricated by the water itself. This manual hopes to show that anyone with a minimum amount of mechanical aptitude can survey, design and build a hydraulic ram from locally available parts and do any necessary maintenance. Whether, for irrigation purposes or domestic, a hydram can be used to great advantage in many diverse situations. The source of water could be a stream, a spring an irrigation canal, and artesian well, or even an existing gravity flow water system. Wilde scale usage would benefit many thousands of people. Because this simple pump works 24 hours per day, for many years and requires little attention, It is suitable for areas where people have little technical expertise. Because hydraulic ram installations are inexpensive and quickly installed, they are extreme transportation difficulties, as well as for sparsely populated villages which often make gravity flow water supply system financially unfeasible. The ability to incorporate a hydram in an existing gravity flow water supply system has also proved very useful.

2.

HISTORY OF THE HYDRAM

Hydraulic ram pump technology has been around since the late 1700’s. The first hydraulic ram pump was discovered and applied by a British man John Whitehurst. In 1772, he produced the first set of the hydraulic ram could not operate automatically. Its valve had to be shut off manually to create the force of water hammering for water lifting. The first automatically hydram was invented by a French man Joseph Montgolfies in 1796. Since the mid 1960s, there has been a growing interest in the potential of hydrams for water pumping applications in the less developed countries. As a result, there are now several different hydram designs available that can be built locally. 3.

OPERATION OF THE HYDRAM 1 Supply tank 2 Gate valve 3. Drive Pipe 4. Waste valve 5. Valve Chamber 9

6. Air Vessel

10 7. Snifter valve

1

6

2

11 3

8 4 7 5

Fig.1. Main components of the hydram

Phyo Min Than is with Mechanical Engineering Department (MED), Mandalay Technological University (MTU), Mandalay, Myanmar. Tel.: +95-02-57363, E-mail: [email protected].

Figure 1 shows the main components of the hydraulic ram pump. The working of a hydraulic ram is based on the principle of water hammer or inertia pressure developed in the supply pipe. Initially the waste valve being open, the water flows

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down the supply pipe into the valve chamber, the water flows through it to the waste water channel. As the rate of discharge past the waste valve increase, the flow of water in the supply pipe accelerates.

Impulse valve opening

Impulse valve open

Snifter valve open Fig.4. Recoil

4. Fig.2. Acceleration

Due to the acceleration of the water column in the supply pipe, an increase of pressure in the valve chamber takes place, in order to develop the necessary velocity of flow of water through the waste valve. The pressure in the valve chamber rapidly increase to such a valve at which the static thrust together with the dynamic thrust acting on the lower face of the waste valve is greater than the downward force due to the weight of the valve. And then, waste valve closes. So, waste valve brings the water in the supply pipe suddenly to rest, causing increase of pressure in the valve chamber. So, the delivery valve is forced open.

SURVEY AND PRELIMINARY DESIGN

The following factors need to be considered in hydraulic ram pump system design. • • • • • • • •

Area suitability (head and flow rate) Flow rate and head requirement Floods consideration Intake design Drive system Pump house location Delivery pipes system Distribution system

A hydraulic ram survey must be done while considering the design. Before a design can be done it is essential to know • • • • • •

Delivery valve open

5.

Vertical fall from source to pump Vertical lift from pump to delivery site Amount of water available to power the pump(Q input or source flow) Minimum daily quantity of water required Drivepipe length from source to pump Delivery pipe length from pump to delivery site. DESIGN OF HYDRAM

The following data processing are used for the hydram design of one dimensional unsteady flow. Fig.3. Delivery

The water flows from the supply tank through the delivery valve into the air vessel and the delivery pipe. Thus some of the water flowing through the delivery valve is directly supplied to the delivery tank and some of it is stored in the air vessel. The water flowing into the air vessel compressed the air inside it, which pushes a part of the water into the delivery pipe even when the delivery valve is closed. An air vessel assists in providing a continuous delivery of water at a more or less uniform rate. The flow of water through the delivery valve continues until the pressure in the valve chamber is reduced, the delivery valve then closes and the waste valve opens, thus again causing the water to flow from the supply tank to the waste water channel. This constitutes one cycle of operation or one beat of the hydraulic ram. The same cycle is then repeated.

Drive head, H

1.524 m

Drive line diameter, D1

0.0762m

Drive line length, L1

7.62 m

Delivery head, h

9.144 m

Delivery pipe diameter, d

0.0381m

Delivery pipe length, L2

10.728 m

Air vessel diameter

0.1524 m

Air vessel length

0.4572 m

Impulse valve diameter

0.0762m

Delivery valve diameter

0.0762 m

Friction factor, f

0.015

2

The maximum waste value weight and fluid velocity can be calculated by the following equation.

Wmax =

2A s HγC d M

(1)

Here, Wmax: denotes the maximum weight of the waste valve, As is the area of the valve seat, H the drive head, γ the unit weight of the water, Cd the drag coefficient in the impulse valve, and M the head loss coefficient for the drive line.

d

g a

V = Vs tanh (gHt/ LVs)

(2)

Where, V describes fluid velocity, Vs the steady – state fluid velocity, g the gravity acceleration, L the length of the drive line, and t the time the valve has been open. The steady state fluid velocity can be calculated by the following equation.

2gH (3) Vs = M Where H is drive head and M the head loss coefficient for the drive line. Then, the one – dimensional unsteady flow during the drive cycle may be expressed by the equation. 2

v L dv = (4) 2g g dt Where f denotes the Darcy friction factor, D the drive line diameter, Ki the impulse valve loss coefficient , Km the coefficient of minor losses in the drive line, A3 the flow area of the impulse valve, and A the flow area of the drive line. Similarly, during the delivery cycle, the unsteady flow equation can be written as H − [(A / A 3 ) 2 + (fL / D) + K m + K i ]

v 2 L dv = (5) 2g g dt Where h denotes the delivery head, A4 the flow area of the delivery valve and Ko the delivery valve loss coefficient. Volume of wasted water during the drive cycle and volume of pumped during the delivery cycle can be calculated by the following equation.

c b

f

Fig.5. The velocity-time relationship in the driveline of a hydram

And then Qd can be calculated by the following equation: Qd =

(Q) p x (Vol) d

Here Qd denotes flow rate wasted during the drive cycle, efficiency can be expressed explicitly as:

h ln(λ 2 H / h + 1) H ln[1 / 1 − λ 2 ]

(12)

λ1 = N/M , λ2 = (Vm/ Vs)2

(13)

η=

Then defining efficiency as:

η(Rankine ) =

L 1A 1 (1) Ln M 1− α

(6)

( Vol ) p =

L2A2 Ln (1 + β ) N

(7)

α = MV2m / 2Gh

(8)

β

(9)

= NV2m/ 2gh

Where (Vol)d the volume of wasted water during the drive cycle and (Vol)p the volume pumped during the delivery cycle. The rate of pumping (Qp) during the delivery cycle can be expressed as

Qp =

(Vol) p (t f − t b )

(10)

Where (tf – tb) represents the time interval between point f and b in figure 5.

hxQ p

(14)

HxQ d

η(D' Aubuission ) =

Q p x (H + h )

(15)

HxQ d

Table 1. Result data

h − [(A / A 4 ) 2 + (fL / D) + K m + K o ]

( Vol ) d =

(11)

(Vol) p

Waste valve weight, W

2.4 kg

Supply flow rate, Qd

1.24 x 10-3 m3/s

Pumping flow rate, Qp

1.05 x 10-5 m3/s

Number of beat per minute, N

70

Fluid velocity, V

1.17 m/s

Steady state fluid velocity, Vs

1.4 m/s

Total time for one beat, t

0.86 s

time for which the waste valve remains open during each beat, t1

0.7 s

time during each beat for which the waste valve remains closed or the delivery valve remains open, t2

0.16 s

Efficiency, η

60 %

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6. CONSTRUCTION AND PERFORMANCE TESTING OF THE HYDRAM The hydraulic ram is constructed as shown in figure 6. In this hydram, the diameter of supply (drive) pipe and delivery pipe are 0.0762 m and 0.0381 m respectively. The waste valve diameter is 0.0762 m and that of the delivery valve is 0.0762 m. The drive pipe and delivery pipe are PVC pipes. The drive pipe is 10.9728 m. Here the variation of the drive pipe length affects the flow rate of the delivery.

Figure 8 is the impulse valve which is an essential component of the ram pump, consists of a steel plate and a rubber seal which are bolted together against each other. It also consists of spring for adjusting the stroke length and tuning the number of beat. There the stroke of the waste valve can be adjusted from 0.0254 m and 0.0381 m. The use of flexible material is to provide the required sealing. The rubber seal is to be fixed in the valve seat.

Fig.9. Air Vessel

Fig.6. Hydraulic ram pump

The pump body or valve chamber is in cylindrical shape and made up of cast-iron. The delivery valve is hinged type as shown in Figure 7.

Fig.7. Delivery valve

It consists of a rubber hollow disc on which a thin steel plate is bolted. It is put in the passage of water to the air vessel to prevent from the back flow of water to the valve chamber. It’s design is to withstand the impact load of pressure changes. But it needs to be flexible not to disturb the flow.

Fig.8. Impulse Valve

Figure 9 is the air vessel which is in cylindrical shaped The volume of air vessel lies between the ranges of 20 to 50 times of delivery volume in one cycle. The air vessel assists in providing a continuous delivery of water at a more or less uniform rate. It is noted that the water level in an air vessel operating normally will be at the top of the delivery outlet. This air volume is the volume of the vessel about this. There is a pressure gauge at the exist or delivery port of the air vessel. It reads in pound per square inch. Especially, the drive head is done to be constand all the time of running. All components of hydram are made at fabrication workshop in Mandalay Technological University. The performance testing is made behind the main building in the Mandalay Technological University and their results are described in the Appendix. Data on hydram were collected for drive heads of 4.5 feet and 5 feet, with 30 feet delivery heads tested for each drive head. Table 1, 2 and 3 indicate the test results obtained with constant head and variable of number of beat per minute which are shown in Appendix. 7.

DISCUSSIONS AND CONCLUSION

This hydram is made by welding method. It can be built simplicity and less cost. Compare with the other water lifting device, the hydraulic ram pump is relatively easy to build and can be made in a simple rural setting workshop. And then, automatic continuous operation requires no supervision or human input. Maintenance was extremely simple, and there as almost no cost to keep the hydram working. So, hydram should be used for water supply to irrigation purposes, village on the hillside, countryside, remote areas and domestic. To obtain the good delivery flow, the efficiency of the pump should be high. There should be a large drive flow and the delivery head should not be too many times the drive head. If the delivery head was taken twenty times the drive head, when working at 100% efficiency, the one

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twentieth of the drive flow can be delivered by the pump. The ratio of the delivery head (H/h) is typically the range of 5 to 25. It is the adequate range for recommendation. It is also the length of the drive pipe be kept to between two and six times the drive head, but should never be less than 6 meter. ACKNOWLEDGMENT The author is gratefully acknowledge to the Ministry of science and Technology, The author would like to express the heart felt gratitude to Dr. Khin Maung Aye, Rector, West Yangon Technological University for the distribution of his invaluable knowledge and experience during the construction of the hydraulic ram pump.

[4] Slack, D.C.,Predicting the performance of a waterpumping hydraulic Ram, International journal for development technology, vol.2,261-271pg.(1984). [5] Dr. Abiy Awoke Tessema, 2000, Hydraulic Ram Pump System Design and Application, ESME 5th Annual Conference on Manufacturing and Process Industry. [6] Modi, P.N., Hydraulics and Fluid Mechanics,. Standard book house, Dehli-110006,1980. [7] Streeter, V.L.,Fluid Mechanics,7th ed., Mc. GrowHill Kogakusha Ltd.,1979. ISBN-0-07-062232-9.

NOMENCLATURE A

area of the drive line

As

area of the valve seat

A3

flow area of the impulse valve

A4

flow area of the delivery valve

Cd

drag coefficient in the impulse valve

g

gravity acceleration

H

drive head

h

delivery head

L

drive line length

M

head loss coefficient for the drive line

N

head loss coefficient for the delivery line

f

Darcy friction factor

Km

coefficient of minor losses in the driveline

Ki

impulse valve loss coefficient

Ko

delivery valve loss coefficient

Qp

pumping flowrate

Qd

supply flow rate

η

efficiency

t

time for one beat in second

t1

time for which the waste valve remains open during each beat

t2

time during each beat for which the waste valve remains closed or the delivery valve remains open. REFERENCES

[1] Prof. Ma Chi of zhejiang University of Technology and Dipl. Eng. Peter Diemer of Bremen Overseas Research and Development Association, 2002, Hydraulic Ram Handbook. [2] Mitchell Silver, 1977, A Guide To Manufacturing And Installation. [3] J.H.P.M. Tack and C . Verspuy, 1989, Hydraulic Rams, Published by: CICAT/Facult of Civil Engineering, by: TU Delft University of Technology, The Netherlands.

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APPENDIX Table A1. Hydram performance with constant head and variable of number of beat per minute ( Stroke Length = 0.0381m) No.

H

h

Qd

Qp (m3/sec)

3

Efficiency

(meter)

(meter)

(m /sec)

(percent)

1

1.524

9.144

1.89×10-3

5.37×10-5

20

2

1.524

9.144

1.33×10-3

7.64×10-5

41

3

1.524

9.144

1.30×10-3

9.62×10-5

52

4

1.524

9.144

1.24× 10-3

1.05×10-5

60

Fig. A1. Characteristics curve of efficiency and pumping flow rate

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Table A2. Hydram performance with constant head and variable of number of beat per minute ( Stroke Length = 0.0254m) No.

H

h

Qd

Qp (m3/sec)

3

Efficiency

(meter)

(meter)

(m /sec)

1

1.524

9.144

1.89×10-3

5.37×10-5

20

2

1.524

9.144

1.33×10-3

7.64×10-5

41

3

1.524

9.144

1.30×10-3

9.62×10-5

52

4

1.524

9.144

1.24× 10-3

1.05×10-5

60

(percent)

Fig.A2. Characteristics curve of efficiency and pumping flow rate

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