FIELD OF THE INVENTION This invention relates to a hydraulic motor, and more particularly to a hydraulic motor arrangement suitable for installation within a pipeline network, such as a water supply network or any other network which provides hydraulic pressure.

BACKGROUND TO THE INVENTION

A hydraulic motor comprises a mechanical actuator that converts hydraulic pressure and flow into torque and linear or rotary displacement. Various hydraulic motors or hydromotor types are known, including gear and vane motors, gerotor motors, axial plunger motors, and radial piston motors.

As is widely known, an input to provide a constant and sufficient supply of hydraulic pressure is required to actuate and operate the hydraulic motor.

Free-flowing rivers, waterfalls and the like provide suitable means for providing such pressure required to actuate and operate the hydraulic motor. In these instances, very little additional energy input, if any, is required to provide the hydraulic pressure. Water supply networks also provide a source of hydraulic pressure. In particular, the gravitational water pressure of water supply networks in mountainous areas provides a useful source of hydraulic pressure. This has lead to the development of hydroelectricity, wherein water supply networks can be utilized for purposes of electricity generation.

A common disadvantage of known hydraulic motors is that when flow of a pressurized liquid, typically water, is interrupted, it causes a drop in pressure, in particular to downstream users.

As a consequence in many instances, water supply networks are not being utilised as a viable option for the generation of hydroelectricity.

OBJECT OF THE INVENTION

It is accordingly an object of the invention to provide a hydraulic motor arrangement, with which the above disadvantage could at least partially be overcome or alleviated.

SUMMARY OF THE INVENTION

In accordance with the invention there is provided a hydraulic motor arrangement operable within a pipeline network, the hydraulic motor arrangement comprising:

- a housing having an inlet and outlet providing a flowpath for liquid therethrough;

- a rotor assembly disposed between the inlet and outlet, the rotor being drivable by the flow of liquid along the flowpath; and - means for reducing pressure proximate one side of the rotor assembly to operatively facilitate rotation of the rotor assembly.

The invention further provides for the means for reducing pressure to include one or more bypass lines extending from proximate the rotor assembly to proximate the outlet of the housing.

Yet further there is provided for the one or more bypass lines to be provided downstream in the flowpath of the rotor assembly.

The invention provides for the inlet to be located at a first side of the housing and the one or more bypass lines to be located at a second opposing side of the housing. The invention further provides for the one or more bypass lines to include a bypass inlet extending from the second side of the housing to a bypass outlet provided at the first side of the housing proximate the outlet.

There is further provided for the bypass inlets of the one or more bypass lines to be spaced radially along the second side of the housing.

The one or more bypass lines may be provided with a control valve.

Another aspect of the invention provides for the rotor assembly to include a rotor shaft having a plurality of vanes shaped to locate substantially flush within the housing to provide minimal clearance between a periphery of the vanes and the housing. The vanes may have a concave operative surface.

Yet further features of the invention provide for the inlet to include a nozzle, and for the nozzle to operatively direct the flow of water to the rotor assembly.

The invention further provides for the hydraulic motor arrangement to include a mount for supporting the housing. A further aspect of the invention provides for the rotor assembly to provide a drive for the generation of electricity or mechanical work for an irrigation system.

The invention further provides for the inlet and outlet to include couplings for installing the arrangement in-line within a closed pipeline of a water supply network, alternatively as a bypass line in the pipeline.

These and other features of the invention are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of an example with reference to the accompanying drawings in which:

Figure 1 is a front perspective view of a hydraulic motor arrangement according to the invention; Figure 2 is a back perspective view of the hydraulic motor arrangement of Figure 1 ; Figure 3 illustrates a top view of the hydraulic motor arrangement shown in

Figure 1 ;

Figure 4 is a sectional front view of the hydraulic motor arrangement as seen along line A-A ¹ in Figure 3;

Figure 5 shows a sectional detail view of B shown in Figure 4; and

Figure 6 is an exploded perspective view of the hydraulic motor arrangement according to the invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

Referring to the drawings, a hydraulic motor arrangement in accordance with the invention is generally indicated by reference numeral 10.

The hydraulic motor arrangement 10 includes a housing 12. The housing 12 is of a cylindrical shape and includes an inlet 14 and an outlet 16 to define a flowpath for liquid, such as water, therethrough. The inlet 14 and outlet 16 are joined to the housing 12 by complementary flanges 18 and includes suitable sealing (not shown) where required.

Suitable couplings 20 as shown are provided for installation in a water supply network (not shown). The hydraulic motor arrangement 10 may be installed inline within a closed water pipeline or alternatively as a bypass line in such pipeline. In the case of the arrangement being installed as a bypass line, suitable valves may be installed in the pipeline to enable the user to selectively direct the water flow through the hydraulic motor arrangement or, when not required, to close off the arrangement to provide the flow through the pipeline only. The installation of the hydraulic motor arrangement 10 within the water supply network will be within the competence of a worker skilled in the art and in accordance with the requirements of a particular installation. As shown in Figure 4, the inlet 14 includes a nozzle 22 for operatively directing the flow of water towards a rotor assembly 24. The reduced diameter size of the nozzle 22 also ensures an increased water pressure directed to the rotor assembly 24. The rotor assembly 24 includes a rotor shaft 26 arranged in the housing 12 with suitable bearings (not shown) to enable rotation of the rotor shaft 26 inside the housing 12. The rotor shaft 26 includes a plurality of vanes 28 which is operatively driven by the flow of water along the flowpath from the inlet 14 to the outlet 16. The direction of rotation of the vanes 28 is indicated by the arrows shown in Figure 4. The location of the nozzle 22 at a first side 30 of the housing 12 directs the water flow to the operatively lower vanes 28 to facilitate the correct direction of rotation of the vanes 28 and rotor shaft 26. The location of the nozzle 22 also contributes to increased pressure at the lower vanes 28.

The vanes 28 are sized to fit substantially flush within the housing to provide a minimal clearance with the walls of the housing 12. This ensures optimal contact of the vanes 28 with the water flow, but still allowing rotation of the rotor assembly 24 within the housing 12 to utilise the water pressure as best as possible. In addition, concave indentations 32 in the vanes 28 are provided to increase the contact surface of the vanes 28 with the water.

The rotor shaft 26 of the rotor assembly 24 is connected to a pulley 34 which is operatively driven by the rotor shaft 26, which drive can be used for any useful purpose, including electricity generation.

At a second side 36 of the housing 12 there is provided a means for reducing pressure proximate side 36. This means is provided in the form of a bypass line 38. The bypass line 38 forms a secondary passage of water through a bypass inlet 40 to a bypass outlet 42. As shown the bypass outlet 42 is located at the outlet 16 of the housing 12 at the first side 30 (opposite the second side 36). In this embodiment, three bypass lines 38 are provided and arranged radially at various positions along the second side 36 of the housing. This arrangement increases the operative area in which the pressure is reduced. The hydraulic motor arrangement 10 also includes a mount 44 to support the arrangement 10 or for mounting the arrangement 10 within the water supply network as the case may be.

The operation of the hydraulic motor arrangement will now be described in detail. It will however be understood that the orientation of the hydraulic motor arrangement may be varied, but for purposes of this description, a horizontal orientation will be described.

In use, pressurised water flows via the inlet 14 though the nozzle 22 into the housing 12. The water contacts the vanes 28 and drives the rotor shaft 26 which in turn drives the pulley 34.

If the water pressure in the upper level (i.e. at the first side 30) of the housing 12 is equal to water pressure in the lower level (i.e. at the second side 36) of the housing 12, the rotor assembly 24 will not turn.

Therefore to remedy this problem the bypass lines 38 have been introduced to reduce the water pressure in the upper level of the housing 12, thus enabling the rotor assembly 24 to turn in the direction of the arrow illustrated in Figure 4. The location of the nozzle 22 as described above also facilitates turning of the rotor assembly 24.

A pressure gradient between the upper level and lower level is operatively formed which facilitates the operation of the rotor assembly 24. A decrease in pressure in the upper level of the housing 12 will result in an increase of pressure in the lower level. Therefore, the more the pressure in the upper level of the housing 12 is reduced, the faster the rotor assembly 24 will turn. In this respect a plurality of bypass lines 38 are provided. These bypass lines 38 are arranged radially as mentioned above, to ensure that the pressure is reduced along a larger area of the second side 36.

The bypass lines 38 are also disposed downstream of the rotor assembly 24. This ensures a reduction of pressure in the area above and downstream of the rotor assembly 24 i.e. directly below the bypass lines 36 as shown in the drawings. This area has been identified as the preferred area in which the water pressure should be reduced to ensure optimal functioning of the system.

The water which flows through the bypass lines 38 is reintroduced into the closed line system at the outlet 16 of the housing 12 through the bypass outlet 42. This increases the pressure at the outlet 16.

The bypass lines 38 will be provided with control valves 46 which regulate the pressure in the bypass lines 38 according to specific requirements of a particular installation. These control valves 46 may be furthermore controlled by an electronic system (not shown) if required.

The arrangement of the components above described facilitates the function of the rotor assembly.

The arrangement will also enable the pressure of the closed pipeline system to remain substantially constant. In other words, the pressure calculated upstream of the hydraulic motor arrangement will be substantially similar to the downstream pressure. This arrangement therefore utilizes pressure provided in a closed line system without a substantial reduction of the overall pressure in the system.

The drive on the pulley may be utilized in any convenient manner which includes the generation of electricity or for use in an irrigation system, or any other useful mechanical work which can be derived from the drive from the pulley.

The invention will be particularly useful in mountainous areas where the water pressure of the closed pipeline system is increased by gravity.

It is envisaged that in future, households may be able to generate their own power from municipal water supply using the hydraulic motor arrangement 10 according to the invention. It is accordingly asserted that the abovementioned disadvantage is at least partially alleviated or overcome by the hydraulic motor arrangement in accordance with the invention. In particular, the disadvantage of a resulting decrease in downstream pressure when a hydraulic motor is inserted into a pressurised liquid supply, such as a water network supply is at least partially overcome by the hydraulic motor assembly according to the invention being able to be installed in the pressurized water supply without causing a significant decrease in downstream water pressure.

It will be appreciated that further variations in details are possible without departing from the scope of the appended claims. It will also be understood that the application of this invention can go beyond that of a water supply network and may include various closed conduit/s or pipeline system which provides hydraulic pressure. In addition, the particular means of installation of the hydraulic motor arrangement in such system may be varied without departing from the scope of the invention. It will also be understood that the length of pipeline in which the invention is operable may be varied.