Hydropneumatic water engine

In a stationary weir erected in a surface water at least one inner shaft (1) is provided which by closure members (2, 3) communicates with the upstream and downstream water levels. In the shaft (1) a sufficiently heavy float (4) is mounted for movement which by its up and down movement actuates an operating chamber (8) of a dual functioning piston pump operating in turn on a liquid chamber of a hydropneumatic pressure storage tank (13). Pressurized fluid (10) which is brought to a high pressure in this manner is supplied to a flow machine, preferably a turbine (20) and expanded and returned to chamber (8) in a closed cycle.

FIELD AND BACKGROUND OF THE INVENTION 
The present invention relate to a hydropneumatic water engine, in which a 
dual-acting piston pump operated by a constantly and slowly moving large 
body of water and which has an operating cylinder coupled to a pressure 
storage container from which the pressurized fluid is fed into an 
expansion chamber of a well-known flow machine, such as a turbine. 
Since thousands of years water powered machines have been known, which used 
the energy of a flowing or of a falling surface water for the driving of 
different work machines, such as mills, water lifting machines, etc. There 
have also been apparatus and equipment known, in which the movement of the 
motion, that is the periodic change of the water level caused by the high 
and the low tides have been made use of. 
The known types of contemporary hydroelectric machines embody the different 
types of water driven turbines. For driving the turbines one requires a 
higher pressure, i.e., a correspondingly high water flow velocity. There 
are hydroelectric stations known, in which the height of the waterfall, 
that is, the level difference between the high water and the low water 
marks is more than 200 meters. In order to attain the necessary height for 
the waterfall, that is, in order to have sufficient storage water 
available, dams are constructed at high cost. 
SUMMARY AND OBJECTS OF THE INVENTION 
The object of the present invention is to provide a water powered engine, 
which makes use of the energy of slowly moving large bodies of water and 
which is able to turn it into a work producing form. 
The above object will be solved by a hydropneumatic water powered machine 
of the above-noted type, in which a weir is ankered in a reinforced bottom 
under a body of water and which, according to the invention, comprises at 
least one input opening of sufficiently large cross section and formed 
above the bottom and which can be closed by closing means and including a 
substantially vertical inner shaft which is communicated by the closing 
means with the high as well as with the low water levels. In each shaft, 
if there are more than one, there is a sufficiently heavily weighted 
floating body mounted for movement in the vertical direction within the 
shaft. The floating body is coupled by means of a longitudinal adjustable 
rod with a liquid pump of a dual-acting piston type communicating on its 
pressure side with the liquid chamber of a hydropneumatic pressure storage 
tank. The pressure storage tank contains above the pressurized liquid 
level compressed air which is being constantly pressurized by the liquid. 
The liquid space of the pressure storage tank is connected by a pressure 
conduit with the expansion chamber of a known flow machine, preferably of 
a turbine or a hydromotor, for a work producing expansion of the hydraulic 
pressurized liquid. 
For the operational control of the water powered machine level sensors are 
provided for sensing the high and low water level and which according to 
the changes of the water level on both sides of the weir, control the 
closure members. 
According to the present invention, the hydraulic pressurized fluid is 
contained in a closed cycle. 
The operating cylinder which is in the form of a dual-acting piston pump, 
on its suction side is coupled by means of a suction conduit with the 
expansion chamber of a collector reservoir serving for the collection of 
the expanded pressurized fluid. 
As a hydraulic pressurized liquid, one may consider the known hydraulic 
oils, or water which should be given an additive of an appropriate nature 
to improve its viscosity and to prevent its sudsing.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
With reference to FIG. 1 it is seen that the water powered machine 
according to the present invention in a sufficiently reinforced bottom 33 
of a river a weir is ankered and in which at least one substantially 
vertical inner shaft 1 is constructed. The weir itself may be 
prefabricated and assembled in the area of construction and formed into a 
serially connected shaft assembly which will span the entire width of the 
river. In the shaft 1 a sufficiently heavy float 4 is guided by means of 
rollers 29 in the vertical direction and freely movable therein. In the 
vicinity of the bottom of the river an inner chamber of the shaft 1 can be 
communicated by means of closure elements 2, 3 which are controllably 
closing and opening the flow passages upstream as well as downstream and 
communicating with the surrounding water. The float 4 is coupled by means 
of a longitudinally movable piston rod 7 of a piston 9. The rod 7 is 
adjustable by a cylinder 6 and gear pump 27, 28. The piston 9 is of a dual 
acting piston pump which on its pressure side is connected to a liquid 
chamber of hydropneumatic pressure storage container 13 and which contains 
an operating cylinder 8 for the hydraulic pressurized liquid. The rod 7 is 
connected with the piston 9 for force and motion transmission, in both 
direction. The rod between the float 4 and the piston 9 includes two ball 
joints 5/a and 5/b for a smooth motion transmission. The liquid chamber of 
the pressure container set on supporting legs 32 and is coupled with both 
chambers of the operating cylinder 9 through an input valve 12 and, it is 
communicating through an output valve 14 and a pressure conduit 18 with an 
expansion chamber 19 of a flow machine, which here is illustrated as the 
wheel of a turbine 20. The pressure container 13 is a pressurized vessel, 
known per se, which above its liquid level has a pressurized air present 
in it and the pressure of its depends from the instantaneous liquid level 
and, at the lower portion, has an output valve 30 for the removal and 
filling of the fluid if necessary as well as for cleaning. The container 
13 on its upper part has a pressure indicator 15, a level indicator 16 as 
well as a built-in level sensor 17 for remote control purposes. In order 
to create a closed cycle for the hydraulic pressurized fluid 10, in the 
expansion chamber 19 of the turbine 20 a collecting reservoir 21 is 
provided, in which the expanded pressurized liquid 10 is collected. The 
reservoir 21 is connected by a valve 22 and a suction conduit 23 with the 
suction side (by means of a built-in flap valve of known construction) of 
the operating cylinder 8 of the dual-acting piston pump 9. 
For an automatic controlling of the machine (which is not illustrated in 
detail) on both sides of the weir, that is, on the high water and also on 
the low water side, level sensors 24 and 25 are provided. The high water 
level is indicated at 26. 
The water powered machine which is illustrated in FIG. 1 in its rest 
position and as described above, will operate in the following manner: 
By opening the closure member 3, the water will flow from the high water 
side in to the shaft 1 and the float 4 will rise. Under the force of the 
rod the piston 9 of the operating cylinder 8 will move upward and the 
pressurized liquid 10 will enter through conduit 11 from the upper 
cylinder chamber into the pressurized storage tank 13. The pressurized air 
in the storage tank becomes further compressed, and an increased pressure 
will be created. 
A constant desired value of the pressure in the storage tank 13 is 
regulated and limited by the pressure regulating valve as far as its upper 
limit is concerned. If now the outlet valve 14 is opened, then the 
pressurized liquid 10 will flow through the pressure conduit 18 into the 
expansion chamber 19 of the turbine 20 and applied in a work producing 
fashion to the wheel of the turbine. It becomes expanded by setting the 
wheel into rotation. From the collector reservoir 21, by opening the valve 
22, the expanded pressurized liquid will be sucked back through the 
suction conduit 23 into the operating cylinder 8 (either into the upper or 
lower cylinder chamber depending on the direction of the stroke). 
After the float 4 has reached its upper limiting position, through a 
signal, the device which automatically controls the entire machine, will 
close the closure member 3 and the closure member 2 will open. The water 
will flow from the shaft 1 out and the float will under the effect of the 
gravity sink downward, whereupon the operating cylinder 8 which will 
function as a pump in the opposite direction, but will still operate on 
the pressurized storage tank 13. When the lower end position of the float 
4 has been reached, then the closure member 2 will be closed and the 
closure member 3 will open, and the above-described process will 
cyclically repeat itself. As a result a stationary steady state operation 
is accomplished. 
The changes in the water level due to supply variation, such as high water 
or during periods of drought, are constantly sensed by the two level 
sensors 24, 25. Their signals serve to regulate the length of the force 
and motion transmitting rod by the operation of the adjusting cylinder 6 
by means of the gear pump 27, 28. Such operation affects the rod setting 
with respect to the water levels on the high water and on the low water 
sides. The gear pumps 27, 28 may be high pressure pumps having a small 
delivery capacity. For the guiding of the float 4 rollers 29 are provided 
which are in the form of rollers journalled in a free running fashion or 
rollers which are provided with an elastic, preferably rubber cover. From 
time to time it may be necessary to put pressurized air into the pressure 
storage tank 13 by means of a fill-up valve 31 in order to compensate for 
possible pressure losses. 
In order to provide a possibly pulsation-free operation, it turned out to 
be an advantage to provide for a single hydropneumatic pressure storage 
tank 13 simultaneously more floats 4 which would be associated with 
several operating cylinders 8 functioning as dual-acting piston pumps and 
which are arranged in a phase-shifted fashion. The water powered machine 
of the invention if made up from such components can serve for the 
structuring of an entire power station. 
Within the scope of the following claims defining the scope of the 
invention are obviously other embodiments and variations are possible 
which may somewhat differ from the above-described embodiments but should 
fall within the scope of the present invention.