Patent Publication Number: US-2004040581-A1

Title: Method of and apparatus for controlling the operation of a suction-type pool cleaner

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
     [0001] This application is a continuation, under 35 U.S.C. § 120 and 365(c), of International Application No. PCT/ZA02/00022, which was filed on Feb. 27, 2002 and designates the US. 
    
    
     
       BACKGROUND OF THE INVENTION  
       [0002] This invention relates generally to the cleaning of swimming pools and more particularly is concerned with controlling the operation of a suction-type pool cleaner which is not connected to an external power source by means of electrical leads.  
       [0003] As used herein “suction-type pool cleaner” includes a device which moves over a submerged surface in a swimming pool and which is connected to a suction inlet, leading to a filtration unit associated with a swimming pool, through the medium of a flexible suction hose.  
       [0004] Suction-type pool cleaners are known in the art. Ideally this type of cleaner should move in a substantially random manner over a submerged swimming pool surface which is to be cleaned. This ensures that the entire submerged surface is cleaned. This ideal is however rarely met in practice in that the movement of the cleaner is subject to external factors such as the geometry of the pool and of the pool surface, the effect of steps and corners inside the swimming pool, the strength of water flow through the cleaner, the amount of dirt in the water, the capability of the cleaner to “climb” the sides of the swimming pool and draw air into the filtration system, and the like. As a consequence of these factors many pools cannot be adequately cleaned by means of a suction-type cleaner.  
       [0005] Electrically driven pool cleaners on the other hand may provide a more comprehensive cleaning activity but are more expensive to purchase and may require facilities which are not normally available at a swimming pool, for example electrical supply connections suitable and safe for use in such environments.  
       SUMMARY OF THE INVENTION  
       [0006] The invention provides a method of operating a suction-type pool cleaner which is not connected via electrical leads to an external power source which includes the step of electrically controlling at least one operating characteristic of the cleaner.  
       [0007] According to one form of the invention the control step is carried out in response to at least one sensed input.  
       [0008] The suction-type pool cleaner may be caused to move by water flow through the cleaner e.g. as in cleaners of the type sold under the name KREEPY KRAULY or BARACUDA.  
       [0009] As used herein “operating characteristics” and “sensed input” include decision making functions, control parameters and input data of, or associated with, the cleaner. Such characteristics and inputs may for example include one or more of: water flow rate through the cleaner; its direction of movement; its speed of movement; its travel path through the water, the condition of the pool floor (submerged surface); the presence of dirt; leaves or other debris; and, the physical structure of the pool, e.g. the presence of steps, corners and other formations, and the like.  
       [0010] The method may include the steps of sensing at least one operating condition of the cleaner, a pool in which the cleaner operates, and a filter system associated with the pool and, in response thereto, of controlling the operating characteristics.  
       [0011] The operating conditions which are sensed may include any one or more of the factors which influence the movement or cleaning action of the cleaner. Such conditions may include; for example, the speed of movement of the cleaner; its direction of movement; its attitude in the water, e.g. horizontal, vertical or inclined; its height in the water above a submerged surface and, in particular, its presence at an air/water interface, i.e. at the surface of the water in the swimming pool; the water flow rate through the cleaner; whether the cleaner is stationary and in operation, or stationary at start-up; and the like. The invention is not limited in this regard.  
       [0012] It also falls within the scope of the invention to store one or more patterns or modes of operating characteristics and to control the operation of the cleaner in accordance with a stored pattern. Thus, according to one aspect of the invention, one or more control characteristics which relate to one or more sets of predetermined parameters pertaining to the cleaner operation are stored and such characteristics are implemented to control the operation of the cleaner, from time to time or continuously.  
       [0013] The cleaner may thus be controlled in response to actual conditions, i.e. on a real time basis or according to stored characteristics, or a combination of both techniques may be employed.  
       [0014] The method may include the step of generating electrical power for controlling the operating characteristics from water flow through the cleaner.  
       [0015] The invention also extends to apparatus for use with a suction-type pool cleaner which is not connected to an external power source by electrical leads which includes electrical energy supply means and control means which is powered by the electrical energy-supply means for controlling at least one operating characteristic of the cleaner.  
       [0016] The apparatus may include means for sensing at least one operating condition of the cleaner and the control means may be responsive to the sensing means, for controlling at least one operating characteristic of the cleaner.  
       [0017] The apparatus may include storage means and the control means may be responsive to data or information stored in the storage means, for controlling at least one operating characteristic of the cleaner.  
       [0018] The electrical energy supply means may include drive means which is responsive to water flow through the cleaner and electrical energy generating means, which is powered by the drive means, for producing a supply voltage which is applied to the electrical energy supply means.  
       [0019] The supply voltage may be regulated or shaped according to requirement to ensure a satisfactory supply voltage for powering the control means.  
       [0020] The apparatus may include a storage device such as a capacitor, battery or any other suitable device, which can be used to supply or build up energy so as to perform, from time to time, tasks requiring high energy usage, e.g. to operate a valve, motor or similar device.  
       [0021] The operating condition or conditions which are sensed by the sensing means may vary according to requirement and for example may include one or more of the following: movement of the cleaner; its direction of movement; its speed of movement; its attitude in the water, e.g. horizontal, vertical or inclined; water flow rate through the cleaner; and the like.  
       [0022] In response to the sensing means, the control means may control one or more operating characteristics of the cleaner selected from the following: water flow rate through the cleaner; its direction or speed of movement, its attitude in the water body; and the strength of a suction type force applied to the cleaner.  
       [0023] To control water flow rate through the cleaner use may be made of a valve, a throttle, a diverter or the like which regulates water flow rate through the cleaner.  
       [0024] To vary the direction of movement of the cleaner, at least one suction inlet may be opened or closed to a required extent, to impart thrust to the cleaner in a desired direction in order to change its direction of movement, or to create friction which causes a change in the cleaner&#39;s direction of movement.  
       [0025] The storage means may include memory means for storing a plurality of parameters relating to pool cleaner movement and such parameters may be employed, in response to the operating conditions of the pool cleaner or on any other predetermined basis, to influence the movement or operating characteristics of the cleaner.  
       [0026] By using one or more valves which are controlled by the control means, or by controlling the movement of wheels which are used to move the pool cleaner over a submerged surface (depending on the type of pool cleaner used), the control means may be used to prevent the pool cleaner from getting stuck in a pool or for increasing the degree of random movement of the pool cleaner.  
       [0027] The control means may be used for causing the pool cleaner to follow a defined route through the pool or to detect dirt in order to move away from surfaces in the pool which are already clean. This may be achieved by fitting sensors of any appropriate type to the cleaner and by causing operation of the control means which is responsive to the sensors. The sensors may be light sensitive, or detect contrasting colors which are indicative of areas to be cleaned or avoided. It is also possible to position one or more markers on the submerged surface which is to be cleaned to cause the pool cleaner to follow such markers, or to be guided by the markers. The markers could be reflective discs, or magnetic strips, which are adhered to the submerged surface at chosen locations. The sensors are designed to detect those markers and, for example, thereupon to cause the cleaner to change direction or proceed in a chosen direction, or take any other appropriate action.  
       [0028] The movement and position of the pool cleaner, relatively to the pool, may be monitored by detecting, wheel movement through the use of suitable indicators such as gears and optical rotation counters.  
       [0029] The invention is preferably based on the following:  
       [0030] (a) generating electrical energy using energy extracted from a flow of water through the cleaner;  
       [0031] (b) using the generated electrical energy to power decision-making electronics which can monitor the movement and action of the pool cleaner and detect data relating to surroundings of the pool cleaner; and  
       [0032] (c) using the data to influence or control at least one of the following: the movement of the pool cleaner, actions of the pool cleaner, and suction through the pool cleaner.  
       [0033] The pool cleaner is then controlled in a way which is dependent on the type of pool cleaner with which the apparatus is used. For example, If the cleaner rides on wheels then a braking pressure may be exerted on one or more wheels to alter the direction of movement of the cleaner. Suction flow to the pool cleaner or from the pool cleaner may also be altered through one or more openings to exert thrust on the cleaner to cause it to move in a desired direction.  
       [0034] The generation of electrical energy may be achieved by making use of any suitable actuator such as a turbine, propeller or water wheel which drives an electrical generator, or use may be made of a paddle, pendulum member or similar device which is moved to and fro, with an oscillatory action, as water flow through the cleaner varies, e.g. of the type used in the KREEPY KRAULY pool cleaner.  
       [0035] The energy which is produced in this way may be transferred to a generator using a mechanical device such as an axle, or by making use of a magnetic coupling.  
       [0036] The apparatus may include one or more input devices for controlling its operation. For example a keypad or similar device may be employed whereby a user may input control information which determines the operation of the apparatus.  
       [0037] It is known that the operation of a suction-type pool cleaner can be influenced by the rate of water flow through the pool cleaner. Conventionally, the water flow rate is throttled to a desired level by making use of a pressure relief valve. In accordance with one aspect of the invention, however, the water flow rate is monitored and use is made of an electrically controlled valve or throttle to adjust the water flow rate to a desired level. In this way the suction strength which is applied to the pool cleaner can be adjusted continuously or automatically to 15 achieve optimal or good results.  
       [0038] A similar technique can be used to relieve the workload on a motor which is driving a pool pump which is used to draw water through the suction-type pool cleaner. For example if the pool cleaner should not move freely, i.e. is stuck at a problem location in a swimming pool, then the lack of movement can be sensed and the pool cleaner can be bypassed so that water flows through one or more alternative openings into a filter system of the pool and not via the pool cleaner into the filter system, until the pool cleaner is freed, either through its own actions or due to external factors. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0039] The invention is further described by way of examples with reference to the accompanying drawings in which:  
     [0040]FIG. 1 illustrates apparatus according to the invention used with a conventional suction type pool cleaner;  
     [0041]FIG. 2 is similar to FIG. 1 but illustrating a different suction-type pool cleaner;  
     [0042]FIGS. 3 and 4 correspond essentially to FIGS. 1 and 2 respectively but illustrate more compact arrangements;  
     [0043]FIG. 5 is a schematic representation of apparatus according to the invention;  
     [0044]FIG. 6 illustrates a variation of the apparatus of the invention;  
     [0045]FIG. 7 schematically illustrates a water wheel for powering the apparatus of the invention;  
     [0046]FIG. 8 is a block diagram of an electrical circuit incorporated in the apparatus of the invention; and  
     [0047]FIG. 9 depicts a sensing switch for use with the apparatus of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0048]FIG. 1 of the accompanying drawings illustrates a conventional pool cleaner  10  of the suction type which is connected by means of a flexible suction hose  12  to a suction inlet in a weir or similar point in a pool filtration system, not shown, and apparatus  14  according to the invention which is connected in-line with water flow through the cleaner  10 .  
     [0049] The cleaner  10  is known in the art and its construction is therefore not described herein save to the extent that a knowledge of the pool cleaner construction may be required for an understanding of the operation of the apparatus  14 . For example, the cleaner may be of the kind sold under the name KREEPY KRAULY or BARACUDA. It is to be noted that the invention applies to cleaners which are not connected to an external power source by means of electrical leads or conductors.  
     [0050] The cleaner  10  includes a body  16  to which is attached a submerged surface engaging flexible disk or foot  18 . A pipe  20  leads from the body and the apparatus  14  is attached to the pipe. Water flow through the body is channeled by the pipe  20  to the flexible suction pipe  12 . The pipe  20  is normally fixed to the body  16  and is rigid but may vary materially in length depending on the type of cleaner.  
     [0051] In use of the cleaner  10 , water flow through the body to the flexible pipe  12  causes movement of an actuator or valve mechanism in the body, in a known way, with the result that the water flow through the flexible pipe  12  is altered or varied in a manner which causes movement of the pool cleaner  10  over a submerged surface. Dirt on the surface is entrained in water which is drawn through the body and is directed to a filter system. As has been indicated these aspects are known in the art.  
     [0052] The apparatus  14  may take on various forms and FIG. 5 illustrates one embodiment of the apparatus, designated  14 A. The apparatus  14 A includes a housing  30  to which are connected an inlet and an outlet spigot  32  and  34  respectively. The pipe  20  is connected to the spigot  32  and the spigot  34  is connected directly or indirectly to the flexible suction hose  12 .  
     [0053] The housing has, in this example, two inlets  36  and  38  on one side of the housing and inlets  40 A and  40 B, respectively, on opposed sides of the housing which lead through respective conduits to a flow passage  42  extending between the spigots  32  and  34 . Valve mechanisms  44 ,  46  and  48 A and  48 B respectively, which are shown somewhat symbolically, are mounted in the respective conduits.  
     [0054] A turbine or water wheel  50  is mounted in the flow passage  42  downstream of conduits  52  and  54  respectively which lead from the inlets  36  and  38 . The turbine drives an electrical generator  56  which produces an electrical voltage which is fed to a power supply unit  58 . Ideally the turbine should be exposed to the full water flow through the suction pipe, i.e. it should be downstream of any inlets to the suction pipe or the flow passage  42  so that its capacity to generate electrical energy is increased.  
     [0055] The unit  58  powers an electronic control unit  66 , which is described in detail hereinafter. Wires  68  from the power supply and one or more sensors, not shown, lead to the control unit and provide information on operating parameters of the pool cleaner or the environment in which it operates. Control leads  70  extend from the control unit to the valves  44 ,  46 ,  48 A and  48 B.  
     [0056] Referring again to FIG. 1, it is evident that when water flows through the body  16  of the pool cleaner  10 , it also flows through the passage  42  in the housing  30  and then to the filtration section of the swimming pool installation. The water flow drives the turbine  50  and the mechanical energy which is thereby produced drives the generator  56 . The electrical energy, as indicated, powers the control unit  66 . This enables the control unit  66 , using information input via the wires  68  from respective sensors, to take decisions regarding the operation of the cleaner according to predetermined requirements.  
     [0057] The sensors may vary according to operating conditions, practical conditions and installation parameters, but typically include one or more of the following: devices which can determine the movement of the cleaner, its speed of movement, its direction of movement, its attitude or orientation in the water, the period for which the cleaner has been in motion and the like. Depending on the input information, the control unit can partially or totally close one or more of the inlets  36 ,  38 ,  40 A and  40 B by operating the respective valves  44 ,  46 ,  48 A and  48 B.  
     [0058] When the valves  44  and  46  are opened, wholly or partially, water flow through the body of the cleaner is diminished. This technique can be used for optimizing the flow rate through the cleaner and allows the normal pressure relief valve, which is mechanically or hydraulically actuated and which is usually associated with a cleaner, to be dispensed with. It is to be noted that the rate at which the turbine  50  moves is, itself, a reflection or measurement of the water flow rate and this can be used to provide information to the control unit to allow the water flow rate to be controlled.  
     [0059] The inlets  40 A and  40 B are on opposing sides of the housing  30 . If water is allowed to flow through one of these inlets, then a reaction force is generated on the housing which tends to displace the rigid pipe  20  to one side and in this way, the direction of movement of the cleaner is gradually altered. The valves  48 A and  48 B can be controlled in response to operating conditions, or on a time or other basis, to ensure  10  that the degree of random movement of the cleaner is varied. The arrangement can be such that the cleaner can be caused to move using the same fundamental principle which drives the cleaner with its normal motion.  
     [0060]FIG. 1 also illustrates flexible conduits  70 A to  70 D respectively which extend from the disk  18  to the body  16  of the cleaner. These conduits are provided in addition to conventional suction holes  72  in the disk. Water flow through these conduits can be controlled in a manner similar to what has been previously described in that each conduit can have a respective valve (similar for example to the valve  44 ) connected to it. Control wires  74  extend from the apparatus  14  to the valves and allow the valves to be opened or closed individually, according to requirement. This allows a further steering action to be exerted on the pool cleaner for uneven suction forces, exerted through the medium of the disk  18 , cause the path of movement of the cleaner to be varied.  
     [0061]FIG. 2 illustrates a cleaner  10 A which is driven in a known manner by making use of an internal turbine or water wheel which imparts direct mechanical movement to wheels  80  which protrude from an underside of a body  82  of the cleaner. The wheels  80  engage a submerged surface and, when rotated, cause the body to move over the submerged surface. Apparatus  14 B, which is essentially the same as the apparatus  14 A described in connection with FIGS. 1 and 5, is connected to a rigid pipe  84  which extends from the body  82 . The water flow rate through the apparatus  14 B is controlled, and directional water jets into the housing of the apparatus  14 B are used, in a manner similar to what has been described hereinbefore, to optimize the operation of the cleaner  10 A and to change its direction of movement. A control wire  86  from the apparatus, instead of controlling valves in suction conduits  70 , as is the case in FIG. 1, is used to control water flow through respective inlets  87  mounted at strategic positions on the body  82 . It is also possible, using electrically actuated brakes  88 , associated with the respective wheels  80 , to inhibit or stop rotation of a chosen wheel in order to change the direction of movement of the pool cleaner.  
     [0062] In the embodiments shown in FIGS. 1 and 2, the apparatus  14  or  14 B is mounted on a pipe which extends from a body of the pool cleaner and is positioned some distance from the body. FIGS. 3 and 4 correspond respectively to FIGS. 1 and 2 but show that the apparatus may be mounted more or less directly on the body  16  or  82  to provide a more compact arrangement. The functions of the apparatus and of the resulting combinations are essentially the same as what has been described herein before.  
     [0063]FIG. 6 illustrates a variation of the apparatus of the invention, designated  14 C. The apparatus includes a housing  90  with an inlet  92  and an outlet spigot  94 . A flow passage  96  extends between the inlet and the outlet and a turbine or water wheel  98  is mounted in the passage. The turbine drives a generator  100  which generates an electrical voltage which is applied to a power supply and control unit  102 . Sensors  104  which are responsive to any desired operating parameters of the cleaner or the environment in which it functions provide information to the unit  102 .  
     [0064] The control unit  102  produces control information taking into account various factors and this information is output via wires  106  to motors  108  or control valves  110 , depending on the type of control function which must be exerted. The valves  110  are shown schematically as units  110 A and  110 B in flow passages  112 A and  112 B, respectively, which extend from inlets  114 A and  114 B in a side wall of the housing  90 . By judicious operation of the valves  110 A and  110 B, directional forces can be imparted to the housing  90  to control its direction of movement and hence alter the direction of movement of a cleaner with which the apparatus  14 C is associated. Similarly, these valves can be used to regulate the suction force.  
     [0065] The apparatus  14 C includes a keyboard  120  or any equivalent input device by means of which control signals can be input to the control unit  102 . A display  122  is provided for a user to ascertain information which is being input, the control function or mode of the unit  102 , or any other appropriate information. An additional control function or interface with the unit  102  can be provided by means of an electronic assembly  124  which may include a memory of stored routines. For example, it is possible to store in the memory a plurality of sequences of operations which can be carried out by the unit  102 , according to requirement, as selected by a user inputting information via the keyboard  120 . It is also possible for a user to build up a library of routines, chosen by the user, as being optimal for controlling the function of a cleaner in a particular swimming pool.  
     [0066] As can be seen, by way, of example only, in FIGS. 2 and 4, the body of the pool cleaner can carry the keyboard  120  and the display  122 .  
     [0067] In a more simple application, the unit  14  may sit directly on a fixed inlet to the pool filtration system on an opposing side of the flexible pipe. In this embodiment, it may control the suction to the pool cleaner and may visually indicate low suction or suction status.  
     [0068]FIG. 7 schematically depicts a turbine or water wheel  98  mounted in a flow passage or path  96 , as described hereinbefore. As has been noted, the speed of rotation of the water wheel, particularly if it is not connected to an electrical generator, is an indication of the water flow rate through the passage  96  and this can be used as a control parameter to the control unit  102  or the assembly  124 , as required.  
     [0069]FIG. 8 is a block diagram representation of the apparatus of the invention. Mechanical energy  130 , produced by water flow through the pool cleaner, drives a water wheel or turbine, ( 98 , see FIG. 6) and this in turn drives an electrical generator  132 . The water wheel may also be in the shape of a sphere or have any other appropriate shape according to requirement. In one embodiment, the generator and water wheel are combined and constitute an armature which is exposed to a magnetic field so that the supply voltage is directly produced. A flywheel or clutch mechanism may be required to convert uneven flow of the turbine into a more even mechanical movement.  
     [0070] The electrical energy produced by the generator  132  is transferred to a power supply unit  134  via wires  136 . In the power supply unit  134 , the voltage from the generator  132  is converted from AC to DC (if required) and is also regulated to an appropriate operating voltage, for example, of the order of 5V. The power supply  134  must also provide an energy storage facility  138  to enable the electronics to continue functioning if the water flow is interrupted. This facility can also be used to provide high power outputs, when required, e.g. to drive a valve or motor with a greater than normal power consumption. This may conveniently be done by means of a backup capacitor or a small onboard rechargeable battery. It is also necessary to smooth out peaks in energy requirements, for example, when the motors  108  or valves  110  are operated.  
     [0071] A reset unit  140  provides for smooth power backup and power down situations when the water flow starts, gets interrupted or stops. A clock/oscillator  142  provides timing to a microprocessor or microcontroller  144 . The control apparatus has a memory unit  146  which may be external and in which are stored predetermined routines or operating parameters, and RAM and read/write non volatile memory (EEPROM or flash).  
     [0072] The non-volatile memory is used, for example, to store parameters selected by a user, or pool data. The memory may also be used for storing reference values relating to suction strength. For example, if the water flow rate through the pool cleaner drops below a desired value, then a warning may be given to the user on the display unit  122  (see FIG. 6).  
     [0073] An interface unit  148  converts analogue signals to and from sensors  150 , which may vary according to requirement. As has been noted, it is possible for example to cause the cleaner to follow markers, e.g. light reflective discs or magnetic strips which are fixed to the submerged surface of the swimming pool. These markers are detected by the sensors  150  to cause the cleaner to follow a predetermined path. The sensors  150  may also detect the presence of dirt on the submerged surface and then divert the cleaner to the dirty area so that it functions more effectively. The sensors may be, light sensitive devices which respond to different or contrasting colors in the pool which indicate, for example, the presence or absence of dirt, or magnetic sensors, as the case may be.  
     [0074] A power electronic unit  152  drives motors  154  which are associated with valves  110  (see FIG. 6) or wheels  80  on a cleaner (see FIG. 2).  
     [0075] An inductive coil  156  is provided as a contactless communication interface between the processor  144  and the outside world. Since this may happen when the pool cleaner is out, the water power should be supplied via this interface.  
     [0076]FIG. 9 illustrates a switch  200  to assist with determining the attitude of the pool cleaner body during use. The switch  200  includes a sealed tube  202  with two pairs of contacts  204  and  206 , respectively, which protrude into the tube. A mercury blob  208 , inside the tube  202 , is freely movable according to the orientation of the tube. When the tube  202  is turned so that the contacts  204  are uppermost, the mercury blob  204  bridges the contacts  206 , and vice versa. The contacts are monitored by means of wires  210  and  212 , respectively, and the information produced by the movement of the mercury blob is input via the interface unit  148  and used by the processor  144  to control movement of the cleaner.  
     [0077] An interface unit  148  converts analogue signals to and from sensors  150 , which may vary according to requirement. As has been noted, it is possible for example to cause the cleaner to follow markers, e.g. light reflective discs or magnetic strips which are fixed to the submerged surface of the swimming pool. These markers are detected by the sensors  150  to cause the cleaner to follow a predetermined path. The sensors  150  may also detect the presence of dirt on the submerged surface and then divert the cleaner to the dirty area so that it functions more effectively. The sensors may be, light sensitive devices which respond to different or contrasting colors in the pool which indicate, for example, the presence or absence of dirt, or magnetic sensors, as the case may be.  
     [0078] A power electronic unit  152  drives motors  154  which are associated with valves  110  (see FIG. 6) or wheels  80  on a cleaner (see FIG. 2).  
     [0079] An inductive coil  156  is provided as a contactless communication interface between the processor  144  and the outside world. Since this may happen when the pool cleaner is out, the water power should be supplied via this interface.  
     [0080]FIG. 9 illustrates a switch  200  to assist with determining the attitude of the pool cleaner body during use. The switch  200  includes a sealed tube  202  with two pairs of contacts  204  and  206 , respectively, which protrude into the tube. A mercury blob  208 , inside the tube  202 , is freely movable according to the orientation of the tube. When the tube  202  is turned so that the contacts  204  are uppermost, the mercury blob  204  bridges the contacts  206 , and vice versa. The contacts are monitored by means of wires  210  and  212 , respectively, and the information produced by the movement of the mercury blob is input via the interface unit  148  and used by the processor  144  to control movement of the cleaner.