Gas flow pressure driven electrical generator

Abstract

The invention relates to gas flow pressure driven electrical generator 30 Generator 30 has a chamber 31 having an inlet 32 connectable to ambient air in a location, and means 35 to connect a chamber outlet 33 through a shut off valve 34 to a dust or fume extraction pipe 20. An airflow turbine36 is provided to generate electricity in the chamber when gas flows from the chamber inlet 32 to the chamber outlet 33.

Description

[0001] Gas Flow Pressure Driven Electrical Generator

[0002] The present invention relates to a gas flow pressure driven electrical generator, especially for use in powering autonomously electrically operated components in dust and fume extraction or general / building ventilation systems.

[0003] Many dust and fume extraction and general ventilation systems extract ambient air from numerous locations in a building or site using a network of branch pipes leading to a main extraction outlet where unwanted contaminants are expelled or filtered. Each of the branch pipes may contain a number of electrical components, such as electrically powered variable aperture control valves, flow rate measurers, and sensors.

[0004] In order to power these components, these traditionally need to be hard wired to a power source. This can involve the installation of many hundreds of metres of cable and cable ties often routed around hard to reach locations. This can be very expensive part of a dust and fume extraction or ventilation system installation.

[0005] The invention seeks to provide a gas flow pressure driven electrical generator to power such electrical components autonomously so avoiding expensive installation.

[0006] According to an aspect of the present invention there is provided a gas flow pressure driven electrical generator comprising: a) a chamber having an inlet connectable to ambient air in a location, and means to connect a chamber outlet to a dust or fume extraction pipe, and b) an airflow turbine disposed in the chamber to generate electricity when gas flows from the chamber inlet to the chamber outlet.

[0007] Preferably, the chamber outlet is connected to the dust or fume extraction pipe through a valve, optionally wherein the valve is a shut-off valve. However, the valve could instead be a variable valve to permit adjustment of air speed through the chamber to enable the turbine to operate at a desired (optimal) operating speed.

[0008] According to another aspect, there is provided a dust or fume extraction system comprising a dust or fume extraction pipe having a variable aperture control valve to control flow rate through the extraction pipe, and a generator as described above and connected to the dust or fume extraction pipe immediately downstream of the control valve in an area of high turbulence created by and adjacent the control valve. The electrical generator may for example be connected to within 1 to 1.5 pipe diameters, or approximately 100mm, of the control valve.

[0009] According to another aspect, there is provided a dust or fume extraction or ventilation pipe having a control valve to control flow rate through the extraction pipe, and a generator according to the above connected to the dust or fume extraction pipe proximate the control valve, wherein the control valve is powered by the generator or by a battery chargeable by the generator.

[0010] According to another aspect, there is provided a dust or fume extraction or ventilation system comprising a dust or fume extraction or ventilation pipe having a control valve to control flow rate through the extraction pipe, a battery, and a generator according to the above connected to the dust or fume extraction pipe proximate the control valve and configured to charge the battery, wherein the control valve is configured to be controlled in dependence on a state of charge or other characteristic of the battery.

[0011] According to another aspect of the present invention there is provided a gas flow pressure driven electrical generator comprising: a) a chamber having an inlet connectable to ambient air in a location, and means to connect a chamber outlet through a shut off valve to a dust or fume extraction pipe, and b) an airflow turbine to generate electricity in the chamber when gas flows from the chamber inlet to the chamber outlet.

[0012] It will be appreciated that the ambient air location to which the inlet is connected may be separate from the source (inlet) of the dust or fume extraction pipe. That is, the chamber is not disposed within the extraction path of the dust or fume extraction pipe, but within a side chamber. Air is drawn through the side chamber (from the ambient air source) into the dust or fume extraction pipe (at the chamber outlet) due to the passage of gas through the dust or fume extraction pipe (due to the Venturi effect). The shut off valve isolates the chamber from the dust or fume extraction pipe when there is no requirement to generate electricity (since the chamber would cause drag and reduce efficiency).

[0013] Preferably the chamber inlet is tapered to accelerate flow of air into the chamber to power the turbine. Preferably the chamber outlet is connected to one side of the shut off valve, and the other side of the shut off valve is connected to a pipe joint which connects to a dust or fume extraction pipe.

[0014] Preferably the pipe joint connects the chamber substantially at 90 degrees to a dust or fume extraction pipe.

[0015] The invention also relates to a dust or fume extraction or ventilation system with one or more dust or fume extraction pipes using a gas flow pressure driven electrical generator as defined above to power its electrical components.

[0016] Preferably each generator is connected at substantially 90 degrees to the dust or fume extraction pipe.

[0017] Preferably one or more dust or fume extraction pipes have a variable aperture control valve to control flow rate through the extraction pipe, and a generator is connected to a dust or fume extraction pipe immediately downstream of the control valve in an area of high turbulence created by and adjacent the control valve.

[0018] Preferably the electrical generator is connected to within 100mm of the control valve.

[0019] In another aspect there is provided a dust or fume extraction system comprising a dust or fume extraction pipe having a valve to control the flow of gas through the extraction pipe, and a generator disposed in or connected to the dust or fume extraction pipe immediately downstream of the valve in an area of high turbulence created by and adjacent the valve to generate electricity as gas flows through the dust or fume extraction pipe. In this way, by disposing the entrance to a side chamber containing the generator, or the generator itself, in a high turbulence (and low pressure) region immediately downstream of the valve, airflow through the turbine of the generator is increased and power output correspondingly increased.

[0020] In another aspect there is provided a dust or fume extraction system comprising a dust or fume extraction pipe having a control valve to control the flow of gas through the extraction pipe, and a generator disposed in or connected to the dust or fume extraction pipe proximate the control valve, wherein the control valve is powered by the generator or by a battery chargeable by the generator. In this way, the control valve can be wirelessly controlled and does not require a wireless connection to a mains power supply or other power source. This improves flexibility in which it can be installed.

[0021] In another aspect there is provided a dust or fume extraction system comprising a dust or fume extraction pipe having a control valve to control the flow of gas through the extraction pipe, a battery, and a generator disposed in or connected to the dust or fume extraction pipe proximate the control valve and configured to charge the battery, wherein the control valve is configured to be controlled in dependence on a state of charge or other characteristic of the battery. In this way, the control valve can be opened when the state of charge of the battery is low, to charge the battery, even where the duct itself is not required to be open to extract dust or fumes. Usually the duct would be closed in such circumstances (to save energy and / or increase energy in parallel ducts driven by the same fan which are in use), but in the case of a low battery opening a duct in these circumstances would be acceptable (until the state of charge has recovered to exceed a predetermined fill level, whereupon the valve can be closed (again, subject to other control inputs which might dictate it to be open to extract dust and fumes)).

[0022] An embodiment of the invention will now be described with reference to the accompanying drawings in which:

[0023] Figure 1 shows a schematic dust and fume extraction system, incorporating the gas flow pressure driven electrical generators of the invention,

[0024] Figure 2 shows an enlarged view of each gas flow pressure driven electrical generator, and Figure 3 shows a further alternative construction of generator to that shown in Figure 2.

[0025] Referring to Figure 1 there is shown a dust and fume extraction system 1. System 1 has a main extractor fan 10 which extracts air out of a main pipe 11, and expels the extracted air through a main extraction outlet 12 where unwanted contaminants are expelled, e.g. to ambient air outside a building, or suitably filtered and returned back into the building.

[0026] A number of branch pipes 20A,20B,20C (only three branch pipes are shown but there could be many more) connect into main pipe 11, and the diameter of the main pipe increases as at 11 A,11B,11C as more branch pipes connect into the main pipe. Typically each branch pipe 20A,20B,20C may extract dust and / or fumes from one work area, and the distance between work areas may be several tens or hundreds of metres.

[0027] In order to control the electrical power consumption of the extraction system the speed of the power consuming main fan 10 may be varied to keep the power consumption to a minimum and a flow rate measurer 13 may need powering. Each of the branch pipes may contain a number of electrical components, such as electrically powered variable aperture control valves 22 and flow rate measurers 23. The valves 22 may be used to close or reduce flow rate through branch pipes from time to time, e.g. when extraction can be reduced or stopped from an area.

[0028] In order to prevent the need for hard wiring the electrical components of the branch pipes to a central power point (usually involving the installation of many hundreds of metres of cable and cable ties often routed around hard to reach locations) the electrical units / components in each branch pipe may be powered with gas flow pressure driven electrical generator 30.

[0029] As shown more clearly in Figure 2, gas flow pressure driven electrical generator 30 has a chamber 31 having an inlet 32 connectable to ambient air in a location such as a work area, and a chamber outlet 33 connected to a dust or fume extraction pipe 20.

[0030] Outlet 33 is connected to one side of a shut off valve 34 and the other side of shut off valve 34 is connected to pipe 20 at an acute angle using a pipe joint 35. A high efficiency airflow turbine 36 is provided to generate electricity in the chamber when the shut off valve 34 is “open” and gas flows through the chamber from the inlet to the chamber outlet. Note for general ventilation systems the gas flow driven generator maybe located in the main branch pipe 20.

[0031] In every branch where there is a partially or fully closed control valve (used for airflow adjustment), there is ‘kinetic energy’ available from the branch air stream, with no additional fan power required. This can be utilised for the high efficiency airflow turbine 36 to generate electricity, and also prevent the main fan 10 from going into a ‘stall’ mode, with the increase in fan speed.

[0032] Because the ambient air pressure at the chamber inlet 32 is higher than the pressure in the extraction pipe 20 when fan 10 is operating, ambient air always flows through the chamber 31 from the inlet to the outlet. This occurs even if the control valves 22 are themselves closed as the generator 30 is downstream of the control valve 22.

[0033] The chamber inlet is tapered to accelerate flow of air into the chamber to power the turbine.

[0034] As shown in Figure 3 the air flowing through the control valve 22 creates an area of low pressure (illustrated by the three wiggly lines) immediately downstream adjacent of the valve 22. If the chamber outlet 33 is connected (via the shut off valve 34 and pipe joint 35) to the extraction pipe 20 at the area of low pressure so air flow through the chamber is increased so increasing the electrical output of turbine 36. It is preferred that outlet 33 is connected to the extraction pipe (via pipe joint 35) within 100mm of the control valve.

[0035] It has been found that the airflow across the turbine can be further increased if the chamber and / or outlet 35 pipe is connected to the extraction pipe 20 at substantially 90 degrees as shown in Figure 3.

[0036] The generator 30 may be used to power any electrical components such as such as electrically powered variable aperture control valves 22 and flow rate measurers 23. The generator 30 may charge a battery which battery can be used to power any electrical components regardless of whether the generator 30 is operating or not at a given time. The generator 30 maybe designed to work in potentially dangerous (flammable / explosive) atmospheres.

[0037] Because the electrical components in each branch pipe are autonomously powered and not hard wired, the components themselves may be wirelessly controlled from a master control centre e.g. using wireless technology.

[0038] The PCB (controller) 50 in Figures 2 and 3 may be used to control the valve 22, as well as the generator and associated components. The controller 50 is able to monitor the state of charge of the battery (which may also power the controller 50), and in the case of the state of charge (or other battery characteristic) satisfying a condition such as being below a threshold level, may cause the valve 22 to be opened, even when it would otherwise be closed (for example because the duct is currently not in use), thereby causing gas to be dragged through the turbine chamber to drive the turbine to generate electricity and charge the battery.

[0039] The invention may take a form different to that specifically described above.

[0040] Further modifications will be apparent to those skilled in the art without departing from the scope of the present invention.

Claims

CLAIMS1. A gas flow pressure driven electrical generator comprising: a) a chamber having an inlet connectable to ambient air in a location , and means to connect a chamber outlet to a dust or fume extraction pipe, and b) an airflow turbine disposed in the chamber to generate electricity when gas flows from the chamber inlet to the chamber outlet.

2. A generator according to claim 1, wherein the chamber outlet is connected to the dust or fume extraction pipe through a valve, optionally wherein the valve is a shut-off valve.

3. A generator according to claim 1 or claim 2, wherein the chamber inlet is tapered to accelerate flow of air into the chamber to power the turbine.

4. A generator according to any preceding claim, wherein the chamber outlet is connected to one side of the shut off valve, and the other side of the shut off valve is connected to a pipe joint which connects to a dust or fume extraction pipe.

5. A generator according to claim 4 wherein the pipe joint connects the chamber substantially at 90 degrees to a dust or fume extraction pipe.

6. A dust or fume extraction or ventilation system with one or more dust or fume extraction pipes using a gas flow pressure driven electrical generator according to any preceding claim to power its electrical components.

7. A dust or fume extraction system according to claim 6 comprising a dust or fume extraction pipe, and a generator according to any of claims 1 to 5 connected thereto at substantially 90 degrees to the dust or fume extraction pipe.

8. A dust or fume extraction system comprising a dust or fume extraction pipe having a variable aperture control valve to control flow rate through the extraction pipe, and a generator according to any of claims 1 to 5 connected to the dust or fume extraction pipe immediately downstream of the control valve in an area of high turbulence created by and adjacent the control valve.

9. The system of claim 8 wherein the electrical generator is connected to within 1 to 1.5 pipe diameters, or approximately 100mm, of the control valve.

10. A dust or fume extraction or ventilation system comprising a dust or fume extraction pipe having a control valve to control flow rate through the extraction pipe, and a generator according to any of claims 1 to 5 connected to the dust or fume extraction pipe proximate the control valve, wherein the control valve is powered by the generator or by a battery chargeable by the generator.

11. A dust or fume extraction or ventilation system comprising a dust or fume extraction or ventilation pipe having a control valve to control flow rate through the extraction pipe, a battery, and a generator according to any of claims 1 to 5 connected to the dust or fume extraction pipe proximate the control valve and configured to charge the battery, wherein the control valve is configured to be controlled in dependence on a state of charge or other characteristic of the battery.

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