Patent Application
20060045733
The present invention relates to water-powered turbine motors and, in particular, it concerns a domestic water turbine motor with an outlet buffer reservoir.
It is known to employ an impeller or turbine type motor for generating mechanical power from a fluid flow. These motors are driven by kinetic energy transferred from the flow of water hitting surfaces of impeller or turbine blades and causing them to turn. The power available from the water flow is a function of its momentum, and therefore proportional both to the flow rate of the water (mass or volume per unit time) and its velocity as it impinges on the blades.
Of particular relevance to the present invention are small water-driven motors of this type which are connected to a domestic water source to power various devices such as, but not limited to, hose reels. Examples of such motors may be found in U.S. Pat. No. 2,518,990 to Keener and U.S. Pat. No. 3,471,885 to McLoughlin et al. Both of these examples relate to applications where the water used to drive the motor is immediately employed for another purpose, either for irrigation or for cleaning a hose. In such cases, a high water flow rate can be used, thereby providing sufficient momentum for driving the motor even at relatively low velocities.
In other applications where the water used by the motor is not required for another purpose, it is desirable to achieve higher volumetric efficiency so as to reduce the quantity of water required by the system. This is done by increasing the velocity of the water impinging on the turbine blades so that the same output power can be derived from a lower flow rate. An example of a motor of this type, designated 10, is illustrated here in
For household or garden applications, the water downstream of the motor must typically be drained to the nearest domestic drain, generally requiring a length of outlet hose 16 downstream of motor 10. This causes an outlet flow impedance which typically slows the initial water drainage rate significantly below the inlet flow rate of the motor. As a result, as illustrated in
There is therefore a need for a water turbine motor employing a jet of water directed through air at blades of the turbine wherein effective drainage from the motor casing is ensured despite significant flow impedance in a drainage line from the motor.
The present invention is a water turbine motor with an outlet buffer reservoir.
According to the teachings of the present invention there is provided, a water-powered turbine motor comprising: (a) a casing having a bottom drainage opening; (b) a rotor having a plurality of blades, the rotor being rotatably mounted within the casing; (c) an output shaft mechanically linked so as to rotate with the rotor; (d) an inlet nozzle associated with the casing for connection to an external source of water, the inlet nozzle configured for generating a stream of water directed towards the blades so as to rotate the rotor, (e) a reservoir deployed beneath the bottom drainage opening for receiving water draining from the casing; and (f) a drainage outlet formed in the reservoir for allowing drainage of water from the reservoir to a remote drain.
According to a further feature of the present invention, a cross-section taken through a volume swept by the rotor passing through an axis of rotation of the rotor has a first area, and wherein the bottom drainage opening has an area greater than half the first area.
According to a further feature of the present invention, the reservoir has an internal volume in excess of one liter, and preferably between about 5 and about 15 liters.
According to a further feature of the present invention, the reservoir is vented to the atmosphere.
According to a further feature of the present invention, the casing and the reservoir together form a unit sealed other than at the inlet nozzle and the drainage outlet.
The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:
The present invention is a domestic water-powered turbine motor with an outlet buffer reservoir.
The principles and operation of turbine motors according to the present invention may be better understood with reference to the drawings and the accompanying description.
Referring now to the drawings,
It is a particular feature of the present invention that motor 100 and 200 further include a reservoir 32 deployed beneath drainage opening 28 for receiving water draining from casing 24. Reservoir 32 has a drainage outlet 34 for allowing drainage of water, typically via a drainage hose (not shown) from reservoir 32 to a remote drain.
It will immediately be appreciated that the present invention provides a highly effective solution to the aforementioned problem of water accumulation within the motor due to drainage impedance. Specifically, by providing a buffer reservoir between the motor casing and the drainage outlet, the present invention ensures that water drains freely from the motor casing so as to avoid water accumulation within the casing. As a result, the casing remains essentially air-filled, thus ensuring minimum drag to oppose rotation of the rotor. This and other advantages of the present invention will be better understood from the following description.
Before addressing the features of the present invention in more detail, it will be helpful to define certain terminology as used herein in the description and claims. Firstly, the present invention is referred to as a “turbine motor”. This terminology is used herein to refer generically to any motor in which a rotating element (referred to as the “rotor”) is caused to rotate by transfer of momentum from a flow of liquid directed asymmetrically relative to the axis of rotation. Examples of motors falling within this definition include all devices working on the principles of water wheels, impeller motors and turbines of all sorts. In particular, the present invention relates to turbine motors suitable for being powered by connection to a domestic water supply. This typically means that the turbine motors of the present invention satisfy one or more of the following conditions: all parts exposed to the working fluid are resistant to corrosion under exposure to water; the nozzle is designed for operating under supply pressures of 2-7 atmospheres; the motor preferably operates with inlet flow rates of at least about 3 liters per minute, more preferably between about 5 and about 15 liters per minute, and most preferably around 10 liters per minute.
Reference is also made to “blades” of the turbine rotor. It should be appreciated that the term “blade” is used herein to refer generically to surfaces of the rotor against which the water flow impinges independent of the shape or configuration of these surfaces. Thus, the “blades” may be flat, curved or angled blades or cups, or any other configuration which provides surfaces deployed so as to be effective for deriving momentum from the water flow.
Turning now to the features of the present invention in more detail, it is a particularly preferred feature of the present invention that the bottom drainage opening 28 of casing 24 provides low hydraulic resistance to flow from the casing into reservoir 32. This is most easily achieved by forming casing 24 as an open-bottomed casing in which there is no bottom wall. In more precise terms, referring to the cross-sectional view of
Turning now to reservoir 32, this is provided by a housing which defines a volume in fluid connection with the internal volume of motor casing 24 but which is not required for rotation of the rotor. In most cases, the reservoir has a horizontal cross-section of area greater than that of the casing around the rotor as seen in
In the embodiment of
V=(Q1−Q2)×t
In other respects, motor 200 is similar to motor 100 and will be fully understood by analogy thereto.
It will be appreciated that the above descriptions are intended only to serve as examples, and that many other embodiments are possible within the scope of the present invention as defined in the appended claims.
