THIS invention relates to cleaners for submerged surfaces. More particularly it relates to suction operable automatic swimming pool cleaners.
Suction operable automatic swimming pool cleaners are known in the art. These machines comprise a body having a planar peripheral region defining an inlet and which region is releasably engageable with a surface to be cleaned. In use, the body is connected via an outlet to an inlet of a pump and filtration system of a swimming pool. In the body there is mounted means for intermittently varying the flow of water through the body, thereby to impart kinetic energy to the body causing the body to move automatically over the surface to be cleaned. As the body moves over the surface, debris is sucked up from the surface through said inlet. One such a cleaner, from which the present invention proceeds, in which the means for intermittently varying the flow of water through the body comprises a pivotal hammer valve is disclosed in US Patent 4,023,227. Another cleaner of the kind described is disclosed in US Patent 4,642,833. In this case the means for intermittently varying the flow of water through the body comprises a pinch valve arrangement. The patent DE-A-1.684.604 shows a suction part, connected by means of a hose to a suction device, comprising liquid guide means.
It is an object of the present invention to provide alternate apparatus for cleaning a surface submerged in a liquid which the applicant believe will have improved operation.
According to the invention, there is provided apparatus for cleaning a surface submerged in a liquid as claimed in claim 1. This apparatus comprising a body defining a flow passage therethrough, the flow passage extending between a main inlet to the body defined in a peripheral region of the body and an outlet from the body, the peripheral region, in use, being releasably engageable with a surface to be cleaned and the outlet being connectable to a suction source; means located in the body for intermittently varying the flow of liquid through the body thereby to impart motion to the body; and liquid guide means for imparting whirling motion to liquid flowing through at least part of the body. This apparatus further comprising at least two inlets defined in asymmetric regions in opposed sidewalls of the body and located between said main inlet and said means to vary the flow of liquid through the body.
The means for intermittently varying the flow of liquid through the body is preferably located downstream of the liquid guide means for imparting whirling motion to liquid flowing through at least part of the body.
The liquid guide means for imparting whirling motion to liquid flowing through at least part of the body may comprise a plurality of curvilinear projections provided in said peripheral region of the body and defining a plurality of curvilinear channels between them.
The plurality of curvilinear projections are preferably provided on a face of a footpad, which is removably mountable on the body in the peripheral region thereof.
The means for imparting whirling motion to liquid flowing through at least part of the body may alternatively or in addition comprise two further inlets defined in asymmetric regions in opposed sidewalls of the body between said main inlet and said outlet. The two further inlets may be offset relative to one another on a line which is substantially parallel to a general plane of the peripheral region. The two further inlets may have different sizes.
In one embodiment of the apparatus according to the invention the body comprises a head defining a chamber communicating with said main inlet and first and second exits from the head; first and second elongate drive tubes communicating with the first and second exits; and a coupling arrangement connected to said first and second tubes and which coupling arrangement defines said outlet from the body; and the means for intermittently varying the flow of liquid through the body comprises a pivotal valve located in the chamber and which valve, in use, pivots between a first position wherein it obstructs said first exit and a second position wherein it obstructs said second exit.
It has been found that it is advantageous to straighten the flow through the drive tubes and therefore at least one of said first and second elongate drive tubes may comprise at least one axially extending internal strake.
Also included within the scope of the present invention is a footpad for a cleaner for a surface submerged in a liquid comprising a disc-like body defining an opening for communicating with a main inlet of the cleaner; a plurality of curvilinear projections provided on one face of the disc-like body defining a plurality of curvilinear channels between them, the channels extending from a peripheral outer region of the body to the opening. At least one of the projections may be made of a resilient porous material.
The invention will now further be described, by way of example only, with reference to the accompanying diagrams wherein:
A suction operable automatic swimming pool cleaner according to the invention is generally designated by the reference numeral 10 in figure 1.
The cleaner comprises a body 12 comprising a head 14, first and second elongate drive tubes 16,18 extending from the head 14 and a coupling arrangement 20. The body defines a flow passage for water therethrough extending between a main inlet 26 to the body and an outlet 41 from the body.
The head 14 has a planar peripheral region 22 provided by a flange 24. The main inlet 26 is defined in the peripheral region. Main inlet 26 communicates with a lower chamber 28 which is bounded by a baffle plate 29 defining a port 30 communicating with chamber 32, for pivotal hammer valve 34. Chamber 32 has first and second exits 36 and 38 communicating with the elongate drive tubes 16 and 18 respectively.
Coupling arrangement 20 comprises a swivel coupling 40 defining outlet 41 and which coupling, in use, is connectable via a flexible hose (not shown), to an inlet of a pump and filtration system (also not shown) of a swimming pool.
As best shown in figure 7, in chamber 32 and about each of exits 36 and 38 there is provided a valve seat 36.1 and 38.1 respectively. Valve 34 having opposed sealing faces 34.1 is mounted off-centre in chamber 32 and, in use, pivots under the influence of water flow through chamber 32, between a first position wherein it obstructs exit 35 and a second position wherein it obstructs exit 38.
As shown in figure 1, a footpad 42 is removably mountable on flange 24. As best shown in figure 2, the footpad 42 comprises a circular body 43 defining a central hole 44, which, in use, communicates with main inlet 26. On the bottom surface of footpad 42 which, in use, bears on the surface being cleaned, there are provided a plurality of curvilinear projections 46 defining a plurality of curvilinear channels 48 extending inwardly towards the hole 44 from the outer periphery of the footpad. At least some of the projections are made of a porous resilient material.
As shown in figures 1 and 3, in opposed sidewalls 14.1 of head 14 and in the region of lower chamber 28, there are defined two further inlets 50 and 52 which are offset relative to one another on a line which is parallel with the plane of the peripheral region 22.
In use, the apparatus assumes the attitude illustrated in figure 1 on a submerged horizontal surface to be cleaned. When suction is applied to the apparatus 10 by the said pump, water entraining debris enters the body via curvilinear channels 48, hole 44 and main inlet 26. The curvilinear channels impart a whirling motion to the water entering the body. Water is also admitted through offset further inlets 50 and 52, which also impart whirling motion to the water admitted.
The water flows through chamber 28, port 30 and chamber 32 towards outlet 41. As more fully described in US patent 4,023,227, water flowing past the valve 34 causes the valve to pivot between the said first and second positions, thereby alternately and repeatedly to obstruct flow through exits 36 and 38. This alternate and repeated obstruction of exits 36 and 38 causes kinetic energy in a body of water stopped as a result of such obstruction, to be transferred to the cleaner body, thereby to cause the cleaner automatically to move over the surface in the direction indicated by arrow B, shown in figure 1.
The projections 46 made of a resilient foam material act like suction pads and serve to improve traction of the footpad 42 on the surface being cleaned.
As illustrated in figure 4, each drive tube 16, 18 comprises a plurality of axially and radially inwardly extending internal strakes 53. These strakes serve to straighten the flow of water as it passes through the drive tubes 16, 18.
As is clear in figure 6, there is defined a clearance 53 between swivel coupling 40 and a bearing 54 which is a friction fit in the body of coupling arrangement 20. A washer 56 is supported on an inwardly directed flange 58 on the body below the lower end of the coupling 40 and is so shaped that water drawn into the coupling arrangement through the clearance 53 is directed along the inside wall of the coupling 40 in the same direction as the main water flow. This arrangement not only reduces vortices in flow in the region of the coupling arrangement 20, but also increases the flow towards the pump by as much as 5%.
The bumper arrangement 60 shown in figure 1 is made of a material having a specific gravity greater than that of water. This increased weight together with the leverage effect of being applied at a distance from the body 12, improves the ability of the cleaner 10 to turn off a sidewall (not shown) of a swimming pool (also not shown).
As shown in figure 1, the external fins 62 on the head 14 are slightly inclined relative to the plane of the peripheral region 22. These fins act like airfoils to press the cleaner 10 into closer contact with the surface being cleaned.
By adopting one or more of the features discussed above, it has been found that there is an increase in the flow of water through the cleaner.
It will be appreciated that there are many variations in detail on the apparatus according to the invention without departing from the scope of the appended claims.