Coil Pump Performance Under Variable Operating Conditions - IWTC

Ninth International Water Technology Conference, IWTC9 2005, Sharm El-Sheikh, Egypt 655

COIL PUMP PERFORMANCE UNDER VARIABLE OPERATING CONDITIONS Sadek Z. Kassab, Ahmed A. Abdel Naby, and El Sayed I. Abdel Basier Mechanical Engineering Department Faculty of Engineering, Alexandria University Alexandria, 21544, Egypt E-mail: [email protected], [email protected]

ABSTRACT Coil pump is considered one of non-conventional water pumping devices which use non-conventional energy sources. It is a self supporting system for pumping water. The performance of coil pump under different operating parameters is the main objective concerned of present study. The parameters considered in the present study are submerged ratios, rotational speed and number of coils of the wrapped hose. The experimental results showed significant effects on the pump performance due to the variation in submerged ratio Sr and the pump rotational speed as well. The presence of air with water for submerged ratios 0 Sr 100% gives the coil pump its pumping action. Increasing the submerged ratio increases the pump flow rate until it reaches its maximum depending on the pump rotational speed, then decreases to zero when the pump is fully immersed. Submerged ratio has a minor effect on the pump maximum static head, it is nearly constant but decreases drastically to zero when the pump submerged ratio reaches 100%. Increasing the pump rotational speed increases water flow rate until it reaches its maximum depending on the working submerged ratio, then the discharge decreases by increasing the rotational speed. Meanwhile slight changes are obtained for the pump static head when the pump rotational speed changes. The number of pump coils is also one of most effective parameters on the coil pump performance. Increasing number of coils increases the pump head while pump discharge is nearly constant. Good agreement is obtained between the present experimental results and theoretical results developed by other investigators.

INTRODUCTION Development of suitable pumping devices to meet the growing demand for water pumping has been a great challenge for those involved in research and development work in that discipline. The variables governing the successful operation of a water pump are numerous and they become particularly difficult to be controlled in the third

656 Ninth International Water Technology Conference, IWTC9 2005, Sharm El-Sheikh, Egypt world developing countries. Developing and testing number of non-conventional pumping devices is one of the greatest importance research works. The key factors are taken into consideration when developing these new systems which use the nonconventional energy sources such as flexibility of the system, minimum maintenance, affordability and use of local raw materials. A very old idea for a simple pump was invented by Archimedes (287 BC-212 BC) had a name "Archimedes Snail Pump". It was used for irrigation and usually powered by human, horses, or mules. A tube was wrapped around a pole, which was then rotated and run with axis of rotation inclined. A similar pump which applied the same principles of operation was invented by Belcher (1972), "The hydrostatic pump", as it was known at that time. In 1979 Morgan invented a pump under the title "A New Water Pump: Spiral Tube". In 1980 "The Stream-powered Manometric Pump" indicated by Stukey and Wilson was tested [1]. Investigations for coil pump types and performance are limited in literature. Theoretical and experimental studies for this pump have been done recently Dibwe [2] constructed his pump as two wooden bearings held the steel water pipe shaft on which the coil was mounted. The pump was hand driven by a crank handle with no gearing. The pump was 1-6 coils. The pump had a better performance with about 5 coils. Using the pump with more than 50% immersion reduced maximum head. Maximum lift obtained was about 6 meters at 25% immersion. Mortimer and Annabel [3] tested theoretically and experimentally a stream powered pump. It consists of a 25 mm diameter flexible pipe wrapped around inside a drum forming 26 coils. This pump was tested in a local stream and it lifted water to a height of 9.5 m at a rate of 4 lit/min. when the stream velocity was 0.8 m/s. Sling pump was built by "Rife Hydraulic Engine Mfg. Co." [4]. A helical intake coil was wrapped around the inside surface of a cone. Sling Pumps can raise water over 80 feet high or move it a mile horizontally, from a stream moving at just 1.5 ft/sec. The unit weighs about 44 lbs and uses a 1/2 inch hose. Another model of the coil pump was undertaken by NERD Center [5]. This pump was under the name of "Barrel pump- rotating coil pump". A flexible hose of predetermined diameter was wound around a water tight barrel. The details of the pump were as follows: Hose diameter = 2.25 in., number of coils = 12, drum diameter = 25 in. and number of water inlets = 1. Stream velocity of 2 to 3 ft/sec would be sufficient to operate the pump and the discharge would vary according to the size of the hose, rotational speed of drum and the delivery head. Sustainable Technology for Watering Livestock [6] presented a project of a simple water pumping device under the name "Barrel Pump" to provide a low maintenance, simple, elegant solution which confers a sense of pride of ownership in the farmer. This pump extracted water from a stream and transported it to storage tank near the


watering trough. It was recommended that the pump only be implemented in situations where it had to move water to 80% of its theoretical capacity. The pump should be capable of functioning water in streams as slow as 0.25 m/s with a depth as shallow as 15 cm. However the typical stream for this pump would be 1.5 m/s current velocity and depths greater than 1 meter. The pump provided a sustained output of 6.8 lit/min. Design of a coil pump and determining its performance under various parameters is the major target of present study. The following parameters will be considered to obtain a clear picture for coil pump performance: • Effects of the pump rotational speed. • Effects of the submerged ratio. • Effects of changing the number of coils. In addition a comparative study will be conducted between the obtained experimental results and theoretical results obtained by other investigators.

EXPERIMENTAL SETUP AND PROCEDURE The experimental setup used in the present study is schematically shown in Figure 1. It is designed and constructed to study the performance of the coil pump at different operating conditions. It consists of a flexible hose (1), of inner diameter 19 mm (3/4 inch) wrapped around a P.V.C cylindrical drum (2), of 1 m total length and outer diameter 20.4 cm (8 inch). The drum is partially submerged into a water tank (3), of dimensions 2 m length, 1.25 m width and 1.25 m height. The submerged ratio of the drum into the water is varied from 15% to 100% of the outer diameter of the flexible hose coil which is wrapped around the drum. The submerged ratio is controlled to be constant by the float control valve (4). One end of the wound flexible hose is open and come in contact with water when rotating forming the pump inlet. The other end of the hose is connected to a steel hollow pipe (5), of 2.5 m total length, 2 inches diameter. This pipe is the axis of the rotating drum and the delivery pipe as well. The outlet of the coil (water and air) passes through non return valve (6), and 2 inch Tee connector (7) to the rotating central hollow pipe. The hollow pipe is divided into four sections, the first section is connected to the pump drive of a geared A.C. motor (8), of 0.37 kW, 1360 rpm and the reduction ratio of the gearbox which is flanged with the motor is 33. The rotational speed of the motor is regulated through a variable frequency inverter (9) in order to study the effect of varying the rotational speed on the pump performance. The power is transmitted from the geared motor to the pump through the V-belt (10) using two pulleys; one of them on the pump shaft (11) and the other is on the geared motor shaft (12). The second section of the hollow pipe is joined with the first section by quick coupling (13), of 2 inches diameter.

658 Ninth International Water Technology Conference, IWTC9 2005, Sharm El-Sheikh, Egypt


The coil on the drum is bounded by two screens; one of them is a steel fixed screen (14), of outer diameter 80 cm and the other is a movable PVC screen (15), of the same diameter and it is easy to slide on the drum to allow studying the effect of increasing and decreasing the number of coils of the flexible hose on the drum and the drum length of winding. The third section is joined with the second section by a non return valve (16), of 2 inches diameter and with the fourth section by the 2 inches Tee connector. The fourth section of the hollow pipe is got through a designed rotary joint (17). In order to obtain the pump performance under different operating conditions. The stationary part of the rotary joint is connected to a vertical flexible delivery pipe (28), of 19 mm (3/4 inch) inner diameter and its length is varied according to the test condition. The pump discharge is collected in tank (29) then in the measuring and calibrated glass collecting tank (30). The central hollow pipe is supported by two symmetrical designed bearing and packing housing supports (19) and (20). The maximum static head of the pump is measured at the pump steady state directly from the scale (32) which has the same reading of the calibrated pressure gauge (21). Detailed explanation of other parts of the coil pump system (see Figure 1) including their construction, purpose and function is given by Abdel Basier [8]. Through out the experimental work the followings are performed: 1. At first, the tank (3) is filled with water up to a certain level depends on the required submerged ratio; this water level is controlled by the float control valve (4). 2. Adjusting the rotating speed required using the frequency inverter (9) to study the effect of rotational speed on the coil pump performance. 3. The vertical delivery pipe (28) has different heights from the pump centerline to allow calculating the pump flow rate at different heads. 4. The pump discharge is collected in tank (29) then in the measuring and calibrated glass collecting tank (30). 5. Collecting a certain volume in the measuring tank (30) in a certain time gives the pump flow rate at a certain rotational speed. 6. Change number of coils for one layer for certain pipe hose diameter and certain drum diameter to obtain the effect of number of coils.

RESULTS AND DISCUSSION 1. Effect of Variation of Submerged Ratio, (Sr) The range of submerged ratios is divided into two groups in the present study. The first group is ranging from 15% to 100%. More details are required to obtain a clear performance, so the second group is from 85% to 100% is performed to identify the submerged ratio effects on the pump performance.

660 Ninth International Water Technology Conference, IWTC9 2005, Sharm El-Sheikh, Egypt 1.1. Effect of Submerged Ratio, (Sr), in the Range from 15% to 100%:

The effect of variation of the pump speed on the performance of the coil pump at various submerged ratio, Sr, is presented in Figure 2. These results are for one layer, for drum diameter, Dd = 8 in, tube diameter, dp = 3/4 in and number of coils, n = 29.5 coils. For a certain submerged ratio, as the rotational speed, N, increases the flow rate, Q, nearly linearly increases, except the case of Sr = 100% there is no flow (Q = 0) for all values of N. Further, for certain rotational speed, N, Figures 2, 3 show that as the submerged ratio, Sr, increases from 15% up to 85%, the water discharge increases. Meanwhile, for Sr = 100% there is no flow Q = 0. This behavior can be explained as follows: For this type of pump the pumping action is obtained due to the presence of air with water within the coiled tube. This explains why there is no pumping action when the submerged ratio is zero, Sr = 0, (not shown in Figures) as well as when Sr = 100%. In the first case, Sr = 0, there is no water, and the coil tube is completely filled with air. While in the second case Sr = 100% the coil tube is completely filled with water. The presence of air with water for submerged ratio 0 Sr 100% gives the coil pump its pumping action while it operates. As the pump is partially immersed, air inters and is blocked between two successive water amounts in the pump coils. When coil pump rotates air pressure increases due to water column, the air act like compression spring creating the pumping action. The compressibility effect as well as the low specific gravity of air with respect to water play dominant effects on the coil pump operation. Figure 4 shows the variation of the maximum water static head for different rotational speed due to changing the submerged ratio at steady state operation of the pump. When pump is running at a certain rotational speed until the static head reaches to its maximum value and that occurs when a fully developed water column is formed in the transparent vertical flexible delivery pipe after air escaping from the delivery pipe and a reverse flow occurs through the pump inlet bore. Significantly, static head changes slightly by changing rotational speed. Figure 5 shows that, the static head increases as increasing the submerged ratio up to 15%, while from 15% to 75% it is nearly constant then decreases drastically to zero when submerged ratio reaches 100%. After presenting the variation of the pump flow rate and head with the pump speed, the performance curves for the pump can be constructed. Figure 6 shows the performance curves (Head, H verses Flow rate, Q) of the coil pump at different submerged ratios and different rotational speeds. It is clear from this figure that, for certain submerged ratio, Sr , as the rotational speed increases the flow rate increases before it starts to fall down to zero as the static head increases reaching a maximum (see Fig. 4). The results presented in Figure 6 are supporting the results shown in Figures 4 and 5. 1.2. Effect of Submerged Ratio, (Sr), in the Range from 85% to 100% To obtain a clear investigations for the pump performance in the range of submerged ratio Sr, from 85% to 100%. It is clearly configured that, in the case of Sr = 100%, the


pump flow rate and static head are zero due to the absence of air which causes the pumping action. Consequently experiments were carried out to study the pump behavior due to increasing the submerged ratio, step by step, from 85% to 100% in the same range of the rotational speeds.

400

one layer dp = 3/4 in

n = 29.5 coils

Dd = 8 in

400

H = 3m

360 Sr=15%

dp = 3/4 in

n = 29.5 coils

Dd = 8 in

H=3m

N1=5.2 rpm N2=11.6 rpm

Sr=25%

320

280

Sr=35% Sr=50%

240

Sr=65% Sr=75%

200

Sr=85% Sr=100%

N3=17.8 rpm N4=23.9 rpm N5=29.8 rpm

280

N6=36.7 rpm N7=42.5 rpm

Q (lit./hr.)

Q (lit./hr.)

320

one layer

360

160 120

N8=48.6 rpm

240

N9=53.7 rpm N10=59.6 rpm

200 160

80

120

40

80 40

0 0

10

20

30

40

50

60

70

0

N (rpm)

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% submerged ratio, Sr (%)

Fig. 3 Variation of the flow rate with submerged ratio (from 15% to 100%) for different rotational speeds

Fig. 2 Variation of the pump flow rate with rotational speed at different submerged ratios (from 15% to 100%)

8 9

one layer

dp = 3/4 in

n = 29.5 coils

Dd = 8 in

dp = 3/4 in

n = 29.5 coils

Dd = 8 in

7

8

6

7

Hst.max. (m)

6 Hst.max. (m)

one layer

5 4 Sr = 15%

3

Sr = 25%

5 N1=5.2 rpm N2=11.6 rpm

4

N3=17.8 rpm N4=23.9 rpm

3

N5=29.8 rpm

Sr = 35%

2

Sr = 50%

1

Sr = 75%

N6=36.7 rpm N7=42.5 rpm

2

Sr = 65%

N8=48.6 rpm N9=53.7 rpm

1

Sr = 85% Sr = 100%

0 0

10

N10=59.6 rpm

20

30

40

50

60

70

N (rpm)

0 0%

10% 20% 30% 40% 50% 60% 70% 80% 90% 100% submerged ratio, Sr (%)

Fig. 4 Variation of max. static head at steady state conditions with rotational speed at different submerged ratios (from 15% to 100%)

Fig. 5 Variation of the max. static head with submerged ratio for each rotational speed



Figure 7 represents the variation of the flow rate with the rotational speeds at different values of submerged ratio, Sr, from 85% to 100%. It can be seen that, for certain value of rotational speed, N, as submerged ratio increases the water flow rate increases for all the submerged ratio, Sr, in the range from 85% to 94.25%. When the submerged ratio increases above 94.25% the flow rate continues to increase to a maximum value for speeds lower than 59.6 rpm, the maximum operating speed presented, before the flow rate decreases to zero. As submerged ratio, Sr, increases in range from 96.9 % to 100% the maximum speed at which the maximum flow rate occurs decreases as the submerged ratio increases. Finally the flow rate reaches zero value for all speeds at Sr s= 100% due to the absence of air with water inside the coil tube pump. From this figure it can be concluded that, increasing the submerged ratios to value close to 100 % increases or decreases the pump flow rate depends on the rotational speed of the pump. Increasing the pump speed increases the flow rate until it reaches its maximum at certain rotational speed and then decreases to zero value due to decreasing of air entering the pump coil during high rotational speeds and higher submerged ratios. In the present study this trend is not obtained for values of submerged ratios less than 85%, see Figures 2 and 3, because of the limitations of rotational speed to 60 rpm. Meanwhile it is expected to obtain the same trend, shown in Figure 7, at higher values of rotational speeds for all submerged ratios. The reason that the rotational speed, N, is limited to 60 rpm. in the present study is the consideration of practical operation of coil tube pump. This type of pump mainly derived by non-conventional drivers, such as water stream which add a limitation to the pump rotating speed. The effect of varying the rotational speed, N, on the pump head, H, at different values of submerged ratio, Sr, in the range from 85% to 100% is shown in Figure 8. For certain submerged ratio, as the speed, N, increases the static head, nearly linearly, decreases. Also for certain speed, N, as the submerged ratio, Sr,, increases the pump static head decreases. For Sr = 100 %, the static head becomes zero. Figure 9 presents an individual (H-Q curves) at different rotational speeds for each submerged ratio. This figure illustrates with magnified details the effect of varying Sr, in the range 88.5 % to 98.5 % on the head, H, versus discharge, Q. A quick view to Figure 9a for Sr = 88.5% and Figure 9g for Sr = 98.5% gives support to the explanations related to Figures 7 and 8.


480

one layer

440

n = 29.5 coils

Dd = 8 in

H=3m

400

Q (lit./hr.)

dp = 3/4 in

360

Sr = 85%

320

Sr = 88.5%

280

Sr = 94.25%

Sr = 93.75% Sr = 96.875%

240

Sr = 97.5%

200

Sr = 98% Sr = 98.5%

160

Sr = 100%

120 80 40 0 0

10

20

30

40

50

60

N (rpm)

Fig. 7 Variation of the flow rate with submerged ratio (from 85% to 100%) at different rotational speeds

6 one layer

dp = 3/4 in

n = 29.5 coils

Dd = 8 in

5

Hst.max. (m)

4

Sr = 85% Sr = 88.5% Sr = 93.75%

3

Sr = 94.25% Sr = 96.875% Sr = 97.5% Sr = 98%

2

Sr = 98.5% Sr = 100%

1

0 0

10

20

30

40

50

60

70

N (rpm)

Fig. 8 Variation of the max. static head with submerged ratio (from 85% to 100%) at different rotational speeds


Fig. 9 Performance (H-Q) curve at different submerged ratios in the range from 88.5% to 98.5%


2. Effect of the Number of Coils The coil pump performance, when changing the number of coils of one layer is obtained for hose diameter (3/4 inch) wrapped around a drum of outer diameter (8 inch) at submerged ratio of 50%. Series of experiments were carried out by using a different number of coils for each experiment at the same other conditions. Figure 10 represents the effect of number of coils on the pump discharge at different speeds. The results can be divided into two groups according to the rotational speed. The first group for pump that rotates at a lower speed less than 30 rpm, the effect of number of coils is nearly constant. This means that, the lower number of coils gives nearly the same discharge as the pump has a higher number of coils. This may be due to lower speed which gives the air chance to be discharged into the pump causes the pumping action. On the other hand, for the second group for pump that rotates at a higher speed over 30 rpm, increasing number of coils increases the pump discharge up to its maximum mainly between 12 and 24 coils then increasing the number of coils decreases the discharge for any rotational speed. Figure 11 shows the relation between the static head and the number of coils for different rotational speed. It is shown that, for all speeds, as the number of coils increases, the pump static head increases. This behavior is due to higher air pumping action as a result of more coils. Due to the relation between the pump flow rate and the number of coils is varied according to the rotational speed; two performance curves (H - Q) are plotted in Figures 12 and 13, one for a rotational speed less than 30 rpm (23.9 rpm) and the other for N more than 30 rpm (53.7 rpm). It can notice that, for low speeds less than 30 rpm the flow rate decreases due to increasing the number of coils and it increases at speeds higher than 30 rpm. Also, it can notice that the static head is reduced due to the reduction in the number of coils for each rotational speed for all cases of the different number of coils. In order to shed more lights on the previously explained effects of the number of coils (or tube length) on the coil pump performance, Figure 14 is drawn for Q versus H at different values of rotational speed N. Comparing Figure 14-a for n = 29.5 coil with Figure 14-e for n = 5 coil one can arrive to a conclusion that as the number of coils decreases (consequently the coil tube length) but the discharge, Q, and the head, H, decreases.


7.5

270

11.6 rpm

240

6.5

23.9 rpm 29.8 rpm

210

11.6 rpm

42.5 rpm

5.5

23.9 rpm

53.7 rpm 59.6 rpm

150 120

Dd = 8in

Sr = 50%

15

20

7.2 rpm

36.7 rpm

Hst.max. (m)

Q (lit./hr.)

dp = 3/4 in

6

48.6 rpm

180

one layer

7

17.8 rpm

17.8 rpm

5

29.8 rpm

4.5

42.5 rpm

4

53.7 rpm

36.7 rpm 48.6 rpm

3.5

59.6 rpm

3 2.5

90

2

60

1.5 1

30 one layer

0 0

3

6

9

dp = 3/4 in

12

15

Dd = 8 in

18

21

Sr = 50%

24

0.5

H = 0.5 m

27

30

0

33

0

5

10

No. of Coils (coils)

Fig. 10 Effect of the number of coils on the pump flow rate at different rotational speeds

120

a) N = 23.9 rpm

one layer

25

30

35

No. of Coils (coil)

dp = 3/4 in

Dd = 8 in

Fig. 11 Effect of the number of coils on the max. static head at different rotational speeds

250

Sr = 50% 29.5 coils

100

b) N = 53.7 rpm

one layer

dp = 3/4 in

Dd = 8 in

Sr = 50%

225

24.5 coils

200

19.5 coils 11 coils 5 coils

175 Q (lit./hr.)

Q (lit./hr.)

80

60

40

150 29.5 coils 24.5 coils

125

19.5 coils 11 coils

100

5 coils

75 50

20

25 0

0 0

1

2

3

4

5

6

7

Hst. (m)

Fig. 12 Variation of the pump performance curve with the number of coils at low rotational speed

0

1

2

3

4

5

Hst. (m)

Fig. 13 Variation of the pump performance curve with the number of coils at high rotational speed


Fig. 14 Performance (H-Q) curve for single layer pump at different numbers of coils

COMPARATIVE STUDY A comparative study is performed between the present results and theoretical results obtained by Mortimer and Annable [6]. They developed a simple coil pump and formed laboratory investigations. A theory had been also produced which satisfactory predicted the behavior of the pump. The motion of the water and air plugs was analyzed through the wrapped pipe from the pump inlet to the outlet and it was found that the pressure head difference across the pump was developed by means of a cascading manometer which was equivalent to an unwound helical coil. The rotation of the pump drum caused the plugs to move along the helical pipe towards the outlet


and each water plug was acting as a manometer and sustained a pressure difference across the plug. The sum of all these pressure differences was equaled the pumping head resulted in the final delivery pipe. So, an investigation into the behavior of the air and water plugs in the delivery pipe was carried out by analyzing the position of the plugs at regular time intervals for one revolution of the pump. Figure 15 shows the position of the air and water plugs in a vertical delivery pipe at a particular time.

Fig. 15 Plug positions in delivery pipe

Figure 16 shows a comparison between the experimental (present study) and theoretical (Mortimer and Annable, 1984) flow rate, at various values of the rotational speed, N, in the range from 5.2 – 59.6 rpm for one layer pump at submerged ratio, Sr = 15%, the hose diameter, dp = 3/4 inches, number of coils, n = 29.5 coils, cylindrical drum diameter, Dd = 8 inches. Good agreement was obtained between the experimental results obtained for pump discharge and theoretical results obtained by Mortimer and Annable especially for lower rotational speeds. While for higher values of rotational speed, higher values of discharge were obtained experimentally not exceeds 20% of the corresponding theoretical values. Figure 17 shows a comparative study for the pump maximum static head obtained experimentally and the theoretical head obtained using Mortimer and Annable theoretical equations. Good agreement for pump maximum static head was obtained at

670 Ninth International Water Technology Conference, IWTC9 2005, Sharm El-Sheikh, Egypt different rotational speeds. It is shown that, the values of the max. Static head, Hst.max., obtained using the theoretical results are comparable with the values obtained experimentally especially for high values of the rotational speeds higher than 25 rpm.

140 130

one layer

120

H=3m

dp = 3/4 in

n = 29.5 coils

Dd = 8 in

Sr = 15%

110 100

Q (lit./hr.)

90 80 70 60 50 40 30 20 Theoretical (Mortimer and Annable (1984)) Experimental (present study)

10 0 0

10

20

30

40

50

60

70

N (rpm)

Fig. 16 Comparison between the theoretical and experimental pump flow rate at different rotational speeds

8 one layer

dp = 3/4 in

n = 29.5 coils

Dd = 8 in

Sr = 15%

7

Hst.max. (m)

6 5 4 3 2 1

Theoretical (Mortimer and Annable (1984)) Experimental (present study)

0 0

10

20

30

40

50

60

70

N (rpm)

Fig. 17 Comparison between the theoretical and experimental maximum static head at different rotational speeds


CONCLUSIONS From the presented results and related discussions the following conclusions can be obtained: 1. Increasing the pump rotational speed increases water flow rate until it reaches its maximum depending on the working submerged ratio and design parameters, and then the discharge decreases by increasing the rotational speed. 2. Increasing the pump rotational speed has a minor effect on the pump maximum static head. 3. Increasing the submerged ratio increases the pump flow rate until it reaches its maximum depending on the pump rotational speed, then decreases to zero when the pump is fully immersed whatever the value of the pump speed. 4. Submerged ratio has a minor effect on the maximum static head, it is nearly constant but decreases drastically to zero when the pump submerged ratio reaches to 100%. 5. Increase number of coils increases the pump head, while pump discharge is nearly constant. 6. Good agreement is obtained between the present experimental results and theoretical results obtained by other investigators. NOMENCLATURE Symbol dp Dd Dc (= dp +Dd) Hst. Hst.max. Lp N n Q S Sr (= S/Dc ) Subscripts P D st. st.max. r

Flexible hose diameter Drum outer diameter Pitch circle diameter Pump Static head Maximum Static head Flexible hose length Rotational speed Number of coils Pump Flow rate Submerged depth Submerged ratio Pipe or hose Drum Static Maximum static Ratio

inch (mm) inch (mm) inch (mm) m m m rpm coil liter/hour mm %


REFERENCES [1] Hoffman, R.D., The Internet Glossary of Pumps created by: The Animated Software Company, http:www.animationsoftware.com/elearning/index.html, USA, 2002. [2] Dibwe, "Hydrostatic Coil Pump – a possible pump design for 3rd world use", a report was written by Alex Weir, Sokoine University, Morogoro, Tanzania 2001. [3] Mortimer, R., "A new water pump: Spiral tube", Department of Civil Engineering, Loughborough University, England, Journal of Hydraulic Research, Vol. 22, No. 1, 1984. [4] Rife Products, water pumps, "Helical intake coil pump: Sling pump", Rife Hydraulic Engine Mfg. Co. www.riferam.com/pump, Image web publishing, 1987, Sweden. [5] Kulasinghe, A.W.S., "Barrel pump-rotating coil pump", Water Pumping Technologies – NERD experience, 20th WEDC Conference: Colombo, Sri Lanka, 1994. [6] Timothy Griffin Report, Sustainable Technology for Water Livestock Project, "Barrel Pump", Holland, 1997. [7] Elsayed, M.M. and Chakroun, W., "An Experimental Course in Thermal Engineering", Kuwait University, 1999. [8] Abdel Basier, E.I. "Coil Pump Design and Performance" M. Sc. Thesis, Faculty of Engineering, Alexandria University, Egypt, 2005.