GB2342699A

GB2342699A - Pumping by heating gas in a pipe

Info

Publication number: GB2342699A
Application number: GB9822493A
Authority: GB
Inventors: Dennis James Carey
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-10-15
Filing date: 1998-10-15
Publication date: 2000-04-19
Anticipated expiration: 2018-10-15
Also published as: GB9822493D0; GB2342699B

Abstract

A pump 10 comprises a loop of ducting 14 having at least two legs 14A,14B submerged to a depth D in water and containing a quantity of gas and liquid. The ducting loop 14 is connected by ducting 20 to an inlet 16 and an outlet 18, the inlet ducting 16 having a greater hydraulic resistance and/or hydraulic impedance than the outlet ducting 18. A solar heat collector 12, which can be orientated relative to the sun, heats the gas in the ducting loop 14 which expands, acing on the liquid in the legs 14A,14B and forcing liquid through the outlet 18. The inlet ducting 16 may alternatively be replaced by a one-way inlet valve.

Description

IMPROVEMENTS IN OR RELATING TO PUMPS The present invention relates to pumps and in particular though not exclusively it relates to pumps which can be solar powered and which contain either no or a minimum number of moving parts.

A pump according to the present invention is based upon an engine known as a Fluidyne Stirling engine.

In a Stirling cycle machine, gas is displaced from a cold space to a hot space and the resulting increase in gas pressure provides power by acting upon a liquid piston. The gas is then displaced back to the cold space so that there is a fall in pressure and the engine is ready to go through the cycle again.

In an adaptation of this principle, known as the Fluidyne engine, two U-tubes which are almost full with water and with three of their four ends joined together through a third tube, a first one of the U-tubes which has one end heated and the other end cold functions as the displacer and the second U-tube functions as a liquid piston. One end of the second U-tube is open to atmosphere.

If the water in the first U-tube is set to oscillate in that U-tube then at one time almost all of the air trapped above the water in the displacer has been forced into one of the limbs of the first U-tube and most of the air is therefore hot and its pressure will rise which tends to force the water in the second U-tube to move. Later the liquid piston will have swung back in the opposite direction forcing the air above it to move into the space above the water at the cold end of the displacer. Most of the air is now in the cold side of the machine and therefore its pressure will fall creating a partial vacuum which tends to pull the water in the output column back in the opposite direction.

Therefore, as long as the liquid piston can be kept oscillating back and forth in its U-tube the water in the second tube will also move back and forth taking the energy which it needs in order to do this from the changing air pressure in the machine.

The air in turn takes this energy from the heat source which keeps the first U-tube of the machine at its operating temperature.

The present invention seeks to provide a modification of the Fluidyne Stirling cycle principle so that only a single closed loop U-tube is required.

A pump according to the present invention need have no moving parts or in one arrangement only a single one-way valve.

Accordingly, the present invention provides a pump providing a continuously closed loop of ducting having at least two legs containing an oscillatable liquid piston and a gaseous medium, means for heating the gaseous medium, the ducting loop being connected to inlet ducting and outlet ducting for a medium to be pumped, the inlet ducting having a greater hydraulic resistance and/or hydraulic impedance than the outlet ducting.

The inlet ducting can be equal to, longer, or shorter than the outlet ducting.

The inlet ducting can include a one-way valve.

A valve can be provided in that part of the ducting loop containing the gaseous medium.

The heating means can comprise a solar heat collector.

The solar heat collector can be oriented continuously relative to the sun in order to maximise the heat input.

The present invention will now be more particularly described with reference to the accompanying drawing which shows diagrammatically one form of pump according to the present invention.

Referring to the drawing, there is shown a pump (10) comprising a solar heat collector (12), and a closed loop of ducting (14) including legs (14A, 14B).

The closed loop of ducting (14) is connected to inflow ducting (16) which has alternative positions, as shown, and outflow ducting (18) by means of ducting (20).

The ducting is submerged to a depth (D) in water and a valve (22) in the ducting loop (14) is open to permit water to enter the ducting and some air to escape within the solar collector. The valve (22) is then closed.

The inlet ducting (16) can be longer, equal to, or shorter than the outlet ducting (18) and has a greater hydraulic resistance, and/or hydraulic impedance and thus acts as a one-way valve.

In operation solar heat causes the air in the ducting loop (14) to expand which pushes the water level down in the legs (14A, 14B). At a certain temperature the water levels in the legs (14A, 14B) starts to oscillate at its natural frequency. An intermittent inflow is created in the inlet tube (16) which results in an intermittent outflow of water from outlet ducting (18).

It will be appreciated that the pump as described above does not include any moving parts and only requires the equivalent of a single U-tube to function. However, in a further arrangement in the inlet ducting (16) can be removed and replaced by a one-way inlet valve at the end of the ducting (20).

The solar collector can be orientated at any appropriate angle in order to maximise the heat input from the sun.

Claims

CLAIMS 1. A pump comprising a continuous closed loop of ducting having at least two legs containing an oscillatable liquid piston and a gaseous medium, means for heating the gaseous medium, the ducting loop being connected to inlet ducting and outlet ducting for a medium to be pumped, the inlet ducting having a greater hydraulic resistance and/or hydraulic impedance than the outlet ducting.
2. A pump as claimed in claim 1 in which the inlet ducting is longer or shorter than the outlet ducting.
3. A pump as claimed in claim 1 in which the inlet ducting includes a one-way valve.
4. A pump as claimed in any one of the preceding claims including a valve in that part of the ducting loop containing the gaseous medium.
5. A pump constructed and arranged for use and operation substantially as herein described and with reference to the accompanying drawing.

5. A pump as claimed in any one of the preceding claims in which the heating means comprises a solar heat collector.

6. A pump as claimed in claim 5 in which the solar collector can be oriented continuously relative to the sun in order to maximise the heat input.

7. A pump constructed and arranged for use and operation substantially as herein described and with reference to the accompanying drawing.

Amendments to the claims have been filed as follows 1. A pump comprising a continuous closed loop of ducting having two legs containing an oscillatable liquid piston and a gaseous medium, means for heating the gaseous medium, and inlet ducting and'outlet ducting for a medium to be pumped connected to that part of the ducting loop containing the liquid piston, the inlet ducting having a greater hydraulic resistance and/or hydraulic impedance than the outlet ducting, but neither the inlet ducting nor the outlet ducting being provided with any valve means.

2. A pump as claimed in claim 1 including a valve in that part of the ducting loop containing the gaseous medium.

3. A pump as claimed in claim 1 or 2 in which the heating means comprises a solar heat collector.

4. A pump as claimed in claim 3 in which the solar collector can be oriented continuously relative to the sun in order to maximise the heat input.