GB2121111A

GB2121111A - Oscillatory pumps

Info

Publication number: GB2121111A
Application number: GB08314364A
Authority: GB
Inventors: Graham Frederick Cox
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-05-26
Filing date: 1983-05-24
Publication date: 1983-12-14
Also published as: GB8314364D0

Abstract

The pump comprises a duct 14 containing a magnet 17 rotatable about an axis 18 transverse to the duct, the magnet being attached to a flexible fin member 19 extending downstream in the duct, and at least one electromagnet 20, 21 arranged to cause oscillation of the magnet and fin. The pump is quiet and may be used for supplying water or air to a fish tank. The pump may be constructed entirely of plastics with the magnetic materials suitably encapsulated. The electromagnets are supplied from an a.c. or intermittent d.c. source 22 via a rheostat 23 to control the pumping rate. <IMAGE>

Description

SPECIFICATION Pumps This invention relates to a pump which is especially but not exclusively useful for supplying water to fish tanks and within fluid systems not necessarily associated with livestock.

Tanks for accommodating fish or other aquatic life commonly require a pumped supply of water to maintain an adequate concentration of oxygen in the water. In known systems air is bubbled through the water from a pipe immersed in the tank and the air is pumped to the pipe by a small electric pump having a vibrating action. Such a pump gives an appreciable amount of noise which can be troublesome in the home.

The present invention is intended to provide a pump suitable for this purpose which produces little or no noise while providing an efficient pumping action.

According to an aspect of the invention, there is provided a pumping device for liquids or gases comprising a duct containing a magnet pivoted for rotation about an axis transverse to the direction of flow of liquid or gas through the duct, the magnet being attached to at least one fin member of flexible material extending downstream of the axis and at least one electromagnet arranged to cause oscillation of the magnet and fin when the electromagnet is fed with fluctuating electric current.

In this aspect the oscillation of the magnet causes a dynamic wave motion in the fin to impel the fluid through the duct. A pair of electromagnets fed from a common source may be mounted outside the duct on either side of the magnet.

The electromagnet may be connected to the source of current through means, such as a rheostat, for varying the current and hence the rate of pumping.

An embodiment of the invention will be described by way of example with reference to the accompanying drawing, which is a diagram showing the essential working parts of a pump arranged to feed water to a fish tank or circulate fluids within any other system.

A duct 14 is arranged to feed gas or liquid from its inlet end 1 5 to its outlet end 16, which may communicate with a pipe to lead the fluid below the surface of water in a fish tank. Within a widened part of the duct is mounted a permanent magnet 1 7 to rotate about an axis 1 8 and the magnet is attached to a fin member 19 of flexible material such as rubber or a resilient plastics material. Electromagnets 20 are positioned outside the duct, as shown, so that one pole of each is close to the respective pole of the permanent magnet. Both electromagnets are wound with coils 21 in series with a source of alternating, or intermittent direct, current 22 and with a rheostat 23.

When alternating current is fed from source 22 the electromagnets 20 are energised in an alternating manner and their action on magnet 1 7 causes the magnet to oscillate in rotation about axis 1 8. This oscillation is transferred to the flexible fin 1 9 and a dynamic wave is thus set up in the fin the effect of which is to impel fluid in the duct towards the outlet 1 6. The same effect is produced if an intermittent direct current is passed through the coils 21. The magnitude of the current and thus the rate of pumping may be varied by means of the rheostat or similar electrical device such as a diode.

When air is pumped at a relatively low pressure the arrangement shown in the drawing will not require any valves and the only moving parts will be the magnet 1 7 and the fin 1 9. However in other applications it is possible to incorporate valves in the duct 1 4 to prevent reverse flow of the fluid being pumped.

In the arrangement described the working parts of the pump in contact with the fluid, including the pivot, are made of plastics material which is resilient to corrosion by aggressive fluids which may be pumped. The pivot may be formed of selflubricating plastics material and the magnet is encapsulated within the armature so that it is protected from the fluid.

It will be understood that many modifications to the arrangement described above may be made. In the arrangement shown in the drawing motion is transmitted to the fin essentially by a first-order lever action but in other arrangements a second-order or third-order lever action may be used.

The pump may be arranged to pass water into a fish tank, in particular the pump may be arranged to pump aerated water into the tank. The water may be withdrawn from the tank itself and recycled to the tank using the pump after aeration.

The device shown in the drawings has a pair of electromagnets mounted on respective sides of the fin but efficient pumping can be obtained with only one electromagnet mounted on one side of the moving magnet.

The devices described are suitable for providing a water supply for fish tanks but they may also be used in other situations where a liquid or gas is to be pumped with a minimum of noise and vibration including systems in which water or other liquid is filtered.

1. A pumping device for liquids or gases comprising a duct containing a magnet pivoted for rotation about an axis transverse to the direction of flow of liquid or gas through the duct, the magnet being attached to at least one fin member of flexible material extending downstream of the axis and at least one electromagnet arranged to cause oscillation of the magnet and fin when the electromagnet is fed with fluctuating electric current.

2. A device according to claim 1 , in which one pair of electromagnets are arranged one on each side of the magnet and the electromagnets are connected to a common source of fluctuating electric current.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Pumps This invention relates to a pump which is especially but not exclusively useful for supplying water to fish tanks and within fluid systems not necessarily associated with livestock. Tanks for accommodating fish or other aquatic life commonly require a pumped supply of water to maintain an adequate concentration of oxygen in the water. In known systems air is bubbled through the water from a pipe immersed in the tank and the air is pumped to the pipe by a small electric pump having a vibrating action. Such a pump gives an appreciable amount of noise which can be troublesome in the home. The present invention is intended to provide a pump suitable for this purpose which produces little or no noise while providing an efficient pumping action. According to an aspect of the invention, there is provided a pumping device for liquids or gases comprising a duct containing a magnet pivoted for rotation about an axis transverse to the direction of flow of liquid or gas through the duct, the magnet being attached to at least one fin member of flexible material extending downstream of the axis and at least one electromagnet arranged to cause oscillation of the magnet and fin when the electromagnet is fed with fluctuating electric current. In this aspect the oscillation of the magnet causes a dynamic wave motion in the fin to impel the fluid through the duct. A pair of electromagnets fed from a common source may be mounted outside the duct on either side of the magnet. The electromagnet may be connected to the source of current through means, such as a rheostat, for varying the current and hence the rate of pumping. An embodiment of the invention will be described by way of example with reference to the accompanying drawing, which is a diagram showing the essential working parts of a pump arranged to feed water to a fish tank or circulate fluids within any other system. A duct 14 is arranged to feed gas or liquid from its inlet end 1 5 to its outlet end 16, which may communicate with a pipe to lead the fluid below the surface of water in a fish tank. Within a widened part of the duct is mounted a permanent magnet 1 7 to rotate about an axis 1 8 and the magnet is attached to a fin member 19 of flexible material such as rubber or a resilient plastics material. Electromagnets 20 are positioned outside the duct, as shown, so that one pole of each is close to the respective pole of the permanent magnet. Both electromagnets are wound with coils 21 in series with a source of alternating, or intermittent direct, current 22 and with a rheostat 23. When alternating current is fed from source 22 the electromagnets 20 are energised in an alternating manner and their action on magnet 1 7 causes the magnet to oscillate in rotation about axis 1 8. This oscillation is transferred to the flexible fin 1 9 and a dynamic wave is thus set up in the fin the effect of which is to impel fluid in the duct towards the outlet 1 6. The same effect is produced if an intermittent direct current is passed through the coils 21. The magnitude of the current and thus the rate of pumping may be varied by means of the rheostat or similar electrical device such as a diode. When air is pumped at a relatively low pressure the arrangement shown in the drawing will not require any valves and the only moving parts will be the magnet 1 7 and the fin 1 9. However in other applications it is possible to incorporate valves in the duct 1 4 to prevent reverse flow of the fluid being pumped. In the arrangement described the working parts of the pump in contact with the fluid, including the pivot, are made of plastics material which is resilient to corrosion by aggressive fluids which may be pumped. The pivot may be formed of selflubricating plastics material and the magnet is encapsulated within the armature so that it is protected from the fluid. It will be understood that many modifications to the arrangement described above may be made. In the arrangement shown in the drawing motion is transmitted to the fin essentially by a first-order lever action but in other arrangements a second-order or third-order lever action may be used. The pump may be arranged to pass water into a fish tank, in particular the pump may be arranged to pump aerated water into the tank. The water may be withdrawn from the tank itself and recycled to the tank using the pump after aeration. The device shown in the drawings has a pair of electromagnets mounted on respective sides of the fin but efficient pumping can be obtained with only one electromagnet mounted on one side of the moving magnet. The devices described are suitable for providing a water supply for fish tanks but they may also be used in other situations where a liquid or gas is to be pumped with a minimum of noise and vibration including systems in which water or other liquid is filtered. CLAIMS

3. A device according to claim 1 or 2, in which the electromagnets are mounted outside the duct.

4. A device according to any preceding claim, in which the fin member is formed of rubber or a resilient plastics material

5. A device according to any preceding claim, in which the magnet is embedded in the material of the fin.

6. A pumping device, substantially as hereinbefore described with reference to the drawing.

7. A method of aerating, filtering or circulating water within a fish tank, which comprises pumping air or aerated water into the tank by means of a pump according to any preceding claim.