PUMPS IN SERIAL CONNECTION

Abstract

The present invention relates to a system (100) for transporting a liquid from a reservoir (600) containing the liquid. The system comprises a first and second conduit (400, 500), each with a lower end (402, 502) and an upper end (404, 504), a first pump (200), with an inlet end (201) and an outlet end (202): wherein one of the lower end (402) of the first conduit (400) or the upper end (504) of the second conduit (500) is connected to a second pump (300): wherein a height difference between the first and second pump (200, 300) is within a maximum pumping height of a lower pump of the first and second pump (200, 300). Further, the present invention relates to a method for operating a plurality of pumps in a system (100).

Claims

1. A system for transporting a liquid from a reservoir containing the liquid, to a level above a liquid surface in the reservoir, the system comprising: an upper coil pump, with an inlet end and an outlet end; a lower coil pump with an inlet end and an outlet end; wherein the inlet end of the upper coil pump is fluidly coupled to the outlet end of the lower coil pump; wherein the inlet end of the lower coil pump is fluidly coupled to an outlet from the reservoir; wherein the upper coil pump is arranged at a higher level than the lower coil pump; and a control system coupled to a sensor, the sensor monitoring the liquid level in the reservoir, the control system being coupled to the coil pumps to control activation and deactivation of the coil pumps depending on the liquid level in the reservoir.

2. The system of claim 1, comprising at least one further coil pump fluidly coupled between an uppermost coil pump and a lowermost coil pump.

3. The system of claim 1, wherein the control system is coupled to a gas inlet valve to operate the gas inlet valve to let gas into a lower coil pump to activate the lower coil pump when the liquid level in the reservoir reaches the level of the inlet end of the coil pump immediately above the lower coil pump.

4. The system of claim 1, wherein a height difference between an upper coil pump is within a maximum pumping height of a coil pump immediately below the upper coil pump.

5. The system of claim 4, wherein the height difference between the upper coil pump and the coil pump immediately below is at least 5 meters.

6. The system of claim 1, wherein the height difference between the upper coil pump and the coil pump immediately below is at least 7 meters.

7. The system of claim 1, wherein the height difference between the upper coil pump and the coil pump immediately below is at least 10 meters.

8. The system according to claim 1, wherein the inlet end or a lower edge of the inlet end of an uppermost pump is arranged at or above the maximum liquid level of the reservoir.

9. The system according to claim 3, wherein the gas inlet valve is arranged at an inlet end of the lower coil pump or in a conduit connected to the inlet of the lower coil pump.

10. The system according to claim 3, wherein the gas is air, oxygen, or oxygen from an oxygen generator together with ozone.

11. The system according to claim 3, wherein an outlet valve is arranged at an outlet end of the coil pump, extracting the gas from the liquid within the coil pump.

12. The system according to claim 11, wherein the outlet valve is operatively connected to the inlet valve for recycling of gas exiting from the outlet end of the coils pump.

13. The system according to claim 12, wherein a return conduit is routed back to the valves at the intake end of another coil pump in the system, recycling the gasses.

14. The system according to claim 1, wherein the control system is coupled to a speed regulator of the coil pumps.

15. The system according to claim 1, wherein the control system is coupled to pressure sensors at the inlet end of the coil pumps.

16. The system according to claim 1, wherein the control system is coupled to pressure sensors at the outlet end of the coil pumps.

17. A method for operating a plurality of coil pumps coupled in series and arranged at different levels, where the total lifting height of the series of coil pumps exceeds the lifting height of each pump, and the series of pumps is coupled to a liquid reservoir, the method comprising: activating an uppermost coil pump of the series of coil pumps when the level of liquid of the reservoir is at or above an inlet to the uppermost coil pump; activating a coil pump of the series of coil pumps immediately below the uppermost coil pump, when the liquid level of the reservoir is below the inlet of the uppermost coil pump; and wherein the activation of the pumps involves supplying gas to the inlet end of the pump and that any pumps below the activated pump(s) are kept full of liquid.

18. The method of claim 17, wherein the supply of gas involves controlling the gas content of the pump with input from pressure sensors at the inlet end and outlet end of the pump.

19. The method of claim 17, wherein the gas is supplied to the coil pump in a sufficient degree to keep the gas/liquid ratio inside the coil pump between 30% and 70%

20. The method of claim 19, wherein the gas/liquid ratio is kept at about 50%.

21. The method of claim 17, wherein pumps that are not activated are turned at an idle speed.

22. The method of claim 17, wherein pumps that are not activated are kept stationary.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0083] Embodiments of the present invention will now be described, by way of example only, with reference to the following figures, wherein:

[0084] FIG. 1 shows schematically a view of the system of serial connected pumps.

[0085] FIG. 2 shows schematically a view of a coil pump used in the system.

[0086] FIG. 3 shows schematically a view of a coil pump used in the system, the coil pump having two parallel coils with a common inlet and outlet end.

PRINCIPLES OF THE INVENTION

[0087] The inventor has realized that by serial connecting suction pumps, wherein the pumps are located at different height levels, that by switching between two operating states the pumps can pump higher than the practical pumping height of a pump.

[0088] The number of pumps in the system is dependent on the total liquid level of the reservoir to be emptied. The number of pumps can be decided upon the liquid level of the reservoir to be emptied divided upon the practical pumping height of the pumps.

[0089] The two operating states are an active state and a passive state.

[0090] In the active state, the pump is operating, and a pump motor is ensuring rotation of the coils of the pump. Air or gas is supplied to the inlet end of the pump and a control system is ensuring a content of approximately 50% air or gas and 50% liquid within each coil of the pump.

[0091] The control system is receiving input from sensors monitoring the amount of air or gas in each pump. The sensors detect e.g. the pressure, flow rate, temperature etc. in the pump.

[0092] In the passive state, the pump is not in operation and no power needs to be supplied to the pump, although it may still be rotating. The coils are completely filled with liquid and a supply of air or gas is not needed. A pumping medium will however be able to pass the coils of the pump, even though the coils are not rotating. If, e.g. fish are part of the pump medium, the fish will not be affected of the coils of the pump, but follow unaffected through the pump, continuously in contact with water.

[0093] When an active upper pump has reached a liquid level at the inlet end of or at the lower edge of the inlet end of a pump below (lower pump), the pump below being in passive mode directly connected to the inlet end of that pump will be activated.

[0094] An uppermost pump will always be operating in active state when the system is operating. When the system is not in operation, all pumps will be in a passive state. When a pump sequence of the system is initiated, the first pump is activated. The inlet end of the uppermost pump being at a height equal to or above the liquid level of the reservoir. When the liquid level is at the inlet end of or at the lower edge of the inlet end of a pump below, the lower pump will be activated and switch from a passive state to an active state.

[0095] When a pump reaches a state where it is no longer able pump because the pressure at its inlet is too low, a pressure sensor at the inlet of that pump, at the outlet of a lower pump or in the conduit connecting the inlet end of the pump to the outlet of the lower pump, triggers a signal to warn about the low pressure and to initiate a start-up/activation of the lower pump being in a passive state. The signal can be a warning signal for an operator, or the signal can be sent to a control unit for automatic action of an appropriate response. The star-up/activation can be manually initiated by the operator or it can be automatically initiated by the control unit. The activation can also be initiated by measuring the water-level in the reservoir. The control unit receives information when the reservoir has reached a given water-level, e.g. at the inlet or at the lower edge of the pump below and initiates a start-up of the lower pump.

[0096] The control system will receive input from monitoring sensors in the system calculating the pressure at the inlet end or outlet end of each pump, the liquid level of the reservoir or the flow rate through the system. The control system will activate a further pump when it receives information that a higher pump of the system has reached a liquid level being at the inlet end of or at the lower edge of the inlet end of the pump below.

[0097] The lower pump is located at a level, preferably at or above the liquid level where the higher pump has reached a liquid level being at the inlet end of or at the lower edge of the inlet end of the pump below. The lower pump will be connected to a motor rotating the lower pump and gas will be supplied to the inlet end of the lower pump.

[0098] A further pump below will be activated and switch from the passive state to the active state when the lower pump reaches a liquid level being at the inlet end of or at the lower edge of the inlet end of the further pump below. If, however, the reservoir is emptied when it reaches this level or before that level, the control system is receiving information from the sensors of the system and will provide a secure shut down of the system.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0099] FIG. 1 shows schematically a view of the system 100. The system 100 shows two pumps 200, 300, but the system is not restricted to only two pumps 200, 300, it may be more, dependent upon the total height of a level of a content, the content being a liquid or a mix of liquid and substances, of a reservoir 600 to be emptied, the reservoir being e.g. a tank, compartment, cage, etc. The system comprises a first pump 200, the first pump 200 comprising an inlet end of the first pump 201 and an outlet end of the first pump 202 and a first conduit 400 with a lower end and an upper end, wherein the upper end of the first conduit 400 is connected to the inlet end of the first pump 200. The system further comprises at least one second pump 300, the second pump 300 comprising an inlet end of the second pump 301 and an outlet end of the second pump 302 and at least one second conduit 400. The outlet end of the second pump 302 is connected to the lower end of the first conduit 400 and the inlet end of the second pump 301 is connected to the upper end of the second conduit 500. The lower end of the second conduit 500 is connected to the bottom of the reservoir 620 or at least constantly in fluid connection with the content of the reservoir 600 to be emptied, at least until it is emptied.

[0100] In a system 100 with two pumps as shown in FIG. 1, the reservoir 600 has two liquid levels; a first liquid level 210 being the uppermost liquid level and a second liquid level 310 being the lowermost liquid level shown in the figure. The reservoir 600 is initially filled with a pump medium, the pump medium being a liquid or a mix of liquid and substances or flowable or pumpable masses. The reservoir 600 is, before the system 100 starts pumping, filled with the pump medium to or below a maximum height. The maximum height being a first liquid level 210. The first liquid level 210 being at the height of the total practical pumping height of the first pump 200 and the second pump 300. The second liquid level 310 is at a level below the first liquid level 210. The maximum height difference between the first liquid level 210 and the second liquid level 310 is maximum the practical pumping height of the first pump 200. The height of the second liquid level 310, from the bottom of the reservoir 620 is the maximum of the practical pumping height of the second pump 300.

[0101] The inlet end of the first pump 201 being arranged at or below the first liquid level 210. When the system 100 is in operation, the first pump 200 will be actuated and start pumping at the first liquid level 210. The pumping medium will be pumped from the reservoir 600 through the second conduit 500, passing the inlet end of the second pump 301, through the coils or windings of the second pump 301 passing the outlet end of the second pump 302, through the first conduit 400, through the inlet end of the first pump 201, through the coils or windings of the first pump 200 and leaves the first pump 200 through the outlet end of the first pump 202. The first pump 200 further comprises an air or gas supply inlet valve (not shown) to the inlet end of the first pump 201 ensuring air or gas supply to the first pump 200 while pumping. When a second liquid level 310 is reached the second pump 300 starts pumping. The second pump 300 further comprises an air or gas supply inlet valve (not shown) to the inlet end of the second pump 301 ensuring air or gas supply to the second pump 300 while pumping. The pumping process continuous until the reservoir 600 is empty.

[0102] FIG. 1 shows two pumps 200, 300 in the system 100, but the system 100 is not restricted to only two pumps 200, 300, it may comprise more than two pumps. The more than two pumps 200, 300 arranged height wise as the two pumps 200, 300 shown in the FIG. 1. Sensors (not shown) are typically arranged at the inlet end of the pumps 201, 301 and at the outlet end of the pumps 202, 302. The control system thus regulates and monitoring the process in order to ensure a continuous flow and sufficient supply of air or gas through the air or gas supply inlet valves.

[0103] FIG. 2 shows schematically a view of a coil pump 700 used in the system 100. The coil pump 700 comprises a helically or coiled tube/conduit rotor of at least two coils or windings 704, wound around an axial axis. The figure shows four coils or windings 704, but it is not restricted to four coils or winding 704, it may have two or three coils or windings 704 and it may have more coils or windings 704. The coils or winding 704 comprises an axial inlet end (not shown) and an axial outlet end (not shown). Rotating couplings (not shown) are arranged at the axial inlet and outlet ends of the rotor, said rotating couplings are supported in a support frame 705. The rotor comprising the coils or windings 704 and axial inlet and outlet ends are rotatably around the axial axis. The rotor is driven by a motor, wherein a driving being a drive belt, drive chain or a drive shaft with a gear.

[0104] The coil pump 700 further comprises an inlet end of coil pump 701 and an outlet end of coil pump 702, corresponding to the inlet end of the first and/or second pump 201, 301 and outlet end of first and/or second pump 202, 302. The inlet end of coil pump 701 and the outlet end of coil pump 702 are connected to conduits 400, 500.

[0105] FIG. 3 shows schematically a view of a coil pump 700 as described in FIG. 2, the coil pump 700 of FIG. 3 having two parallel coils or windings 704, wound in opposite direction. The coil pump 700 has a common inlet end of coil pump 701 and outlet end of coil pump 702. The parallel coils or winding 704 forming the rotor are rotatable in opposite direction and each coil or winding 704 are driven by two separate motors.

[0106] It is described and shown a system 100 for transporting liquids or liquids in a mix with particles in a vertical direction, but it is not restricted to such use. The system may also be utilized for transporting in horizontal direction or a combination of vertical and horizontal direction. The pumps of the system 100 being arranged in a serial connection between conduits, where one end of one of the conduits is connected to a reservoir 600.

TABLE-US-00001 TABLE 1 Component Description 100 System 200 First pump 201 Inlet end of first pump 202 Outlet end of first pump 210 First liquid level 300 Second pump 301 Inlet end of second pump 302 Outlet end of second pump 310 Second liquid level 400 First conduit 402 Lower end of first conduit 404 Upper end of first conduit 500 Second conduit 502 Lower end of second conduit 504 Upper end of second conduit 600 Reservoir 610 Height of reservoir 620 Bottom of reservoir 700 Coil pump 701 Inlet end of coil pump 702 Outlet end of coil pump 703 Air or gas supply inlet valve 704 Coil or winding 705 Supporting frame