GB2231098A - Air compressor - Google Patents

Abstract

An air compressor comprises one or more water catchments (6) the or each having an associated variable volume air container which is contracted when water is supplied thereto. As the or each catchment fills with water, the buoyant lower part of its container moves upwardly, compressing the volume of air in the container. When the catchment is full of water, the compressed air is taken to storage through an outlet valve (4) and the catchment emptied, allowing the container to expand and refill with air from atmosphere, via an inlet valve (3). The or each variable volume chamber may be defined by a bellows or by a piston slidable in a cylinder. <IMAGE>

Description

COMPRESSOR SYSTEM The present invention relates to a compressor and to a compressor system. More particularly, but not exclusively, it relates to a compressor system operated by a gravity fed fluid, such as water. The downf lowing water compresses air in discrete containers and the collected compressed air may be used to power a turbine or the like.

It is known to dam rivers and streams to provide a head of water intended to power turbines, but this, whilst being acknowledged to be more efficient than many other forms of energy conversion, is capable of further improvement. This is especially true since a water turbine requires a large quantity of water at a large force (i.e.

head) At times of heavy rainfall, dams generally have a large overspill, which is in effect, wasted energy. It is one object of the present invention to provide a system capable of utilising such wasted potential energy.

Furthermore, it is possible to utilise the present system to extract potential energy from smaller heads of water, thus avoiding the need of constructing large dams.

According to one aspect of the present invention, there is provided a compressor operable by gravity fed fluid, comprising a catchment means into which said fluid may flow and from which said fluid may empty at determinable intervals, such that said catchment means alternately fills with and empties of said fluid, a compressible container located in said catchment means and having at least one lower surface adapted to be buoyant in said fluid and an upper surface fixed whereby said container is compressible between a minimum volume when said catchment means is filled with said fluid and a maximum volume when said catchment means is emptied of said fluid, non-return inlet valve means to allow air into said container as it expands towards its maximum volume, and a non-return outlet valve means to allow escape of compressed air when the container is compressed towards its minimum volume.

According to another aspect of the present invention, there is provided a compressor system comprising a plurality of interconnected compressors each as described above.

An embodiment of the present invention will now be described by way of example and with reference to the accompanying drawings, in which: FIGURE 1 is a perspective view of a pair of parallelly arranged catchment series; FIGURE 2 is a view of a compressor container unit with bellows compressed; FIGURE 3 is a view of a compressor container unit with bellows expanded; FIGURE 4 is a side view, partially cut away, of a series of compressors arranged in a sequence of terraces; FIGURE 5 is a view from above of a series of compressors; and FIGURE 6 is a side view of a series of compressors.

Referring now to the drawings, there is shown in -Figure 1 a top pair of a double series of compressors. A single series could be provided br indeed such a series could be multiplied as desired to make most efficient use of the amount of water.

Each compressor comprises a container unit 1 with, at its upper part, a container having bellows sides 2. The container unit stands in a catchment 6 forming part of a gravity water flow system. In an alternative embodiment, which is not illustrated, the container may have rigid sides, but form a "cylinder" tof whatever desired crosssectional shape) into and out of which a piston may move to vary the volume.

Each container has a non-return inlet valve 3 to allow air to enter the container as it expands in volume.

Each container also has a non-return outlet valve 4 to permit egress of compressed air when the container is contracted, the outlet valves 4 of the containers being connected together to direct the flow of compressed air to a storage container or directly to a turbine (not shown).

The containers expand and contract, within guides in a frame 5 of each container unit 1, under the influence of water leaving or entering the catchment 6 in which they are situated. At least a lower part of each container is buoyant in the water and accordingly rises and falls with the water level.

To operate a series of such compressors, an upper sluice gate 8, at the head 7 of a dam, is opened allowing water to fill the uppermost catchment. This compresses the respective container and the air in it. When the container reaches a minimum volume a trip or level switch opens a lower sluice gate 8 and closes the upper gate 8. The water level in that catchment thus falls and the container expands. When the container reaches a maximum volume a second trip or level switch reopens the upper sluice gate 8 .and closes the lower sluice gate, thus repeating the cycle.

The lower sluice gate of the first catchment may be the upper sluice gate of a second catchment, which fills as the first is emptying. The first and second catchments may be connected indirectly or by means of a pipe, depending on the relative disposition of catchments.

If each catchment in a series is of similar volume, the system should operate with alternate containers being compressed and those between being allowed to expand.

As can be seen, the potential energy of the water is extracted, or converted, in a series of comparatively small steps, which allows great variation in applicability of the system.

The amount of water passing through the system may be controlled by varying the degree of opening of each of the sluice gates 8 in the system.

The system has the advantages over conventional water turbine energy conversion in that there is no need for a large head of water. Thus it is not necessary to build expensive dams and flood large areas of potentially fertile land. The compressors may be installed singly or in a series wherever there is a natural fall in a waterway. This may be particularly important in less developed countries.

Claims (13)

1. A compressor operable by gravity fed fluid, comprising a catchment means into which said fluid may flow and from which said fluid may empty at determinable intervals, such that said catchment means alternately fills with and empties of said fluid, a compressible container located in said catchment means and having at least one lower surface adapted to be buoyant in said fluid and an upper surface fixed whereby said container is compressible between a minimum volume when said catchment means is filled with said fluid and a maximum volume when said catchment means is emptied of said fluid, non-return inlet valve means to allow air into said container as it expands towards its maximum volume, and a non-return outlet valve means to allow escape of compressed air when the container is compressed towards its minimum volume.

2. A compressor as claimed in claim 1, wherein the container comprises bellows means.

3. A compressor as claimed in claim 1, wherein the container comprises a cylinder closed at its lower end by a movable piston.

4. A compressor as claimed in any one of the preceding claims, wherein there are provided means to allow ingress of fluid to said catchment means, said means being actuatable when said container attains substantially its maximum volume.

5. A compressor as claimed in any one of the preceding claims, wherein there are provided means to allow egress of said fluid from said catchment means, said means being actuatable when said container attains substantially its minimum volume.

6. A compressor system comprising a plurality of compressors as claimed in any one of the preceding claims, the catchment means of each compressor apart from an uppermost one being filled with fluid exiting from a catchment means of an adjacent compressor.

7. A compressor systems comprising a plurality of compressors as claimed in any one of claims 1 to 5, the catchment means of each compressor apart from a lowermost one being emptied into a catchment means of an adjacent compressor.

8. A compressor system as claimed in either claim 6 or claim 7, wherein the non-return outlet valve of each compressor is connected to a common compressed air storage means.

9. A compressor system as claimed in any one cf claims 6 to 8, further comprising turbine means powered by said stored compressed air.

10. A compressor system as claimed in any one of claims 6 to 9, comprising a series of catchment means arranged in a descending series of terraces.

11. A compressor system as claimed in claim 10, wherein said terraces are located adjacent a face of a dam.

12. A compressor substantially as described herein with reference to the accompanying drawings.

13. A compressor system substantially as described herewith with reference to the accompanying drawings.