GB2110375A - Remotely readable compasses - Google Patents

Abstract

A compass whose reading can be sensed at a remote position by telemetry equipment comprises a magnet 1 embedded in a spherical block 2 located within a spherical housing and floating in appropriate fluid 3. Sensing coils, or light sensing devices, are provided within the housing 4 to provide variable signals as the magnet hunts about magnetic north and these signals are processed by a microprocessor, to ascertain the position about which the magnet is hunting. <IMAGE>

Description

SPECIFICATION Remote compass This invention relates to compasses which may be used with telemetry equipment to enable the deviation from magnetic north to be determined from a remote point.

The remote compass is particularly designed to be used in a drilling rig in accordance with my copending application No. 8134337, filed simultaneously herewith and entitled "Drilling Equipment and method". However, its use is not to be regarded as restricted to such an application.

According to the invention, there is provided a remotely usable compass comprising a magnet suspended in a housing with freedom to seek magnetic north, a series of sensing devices in the housing to generate signals dependent on the position or movement of the magnet, and means for processing the signals to ascertain the position of the magnet relative to the housing.

The shape of the magnet will provide differentiation between north and south.

The sensing devices are preferably sensing coils but light sensing devices, associated with fibre optics, may alternatively be used.

The signals from the sensing device may be processed in a microprocessor to ascertain the position of the magnet in relation to the housing.

In the case of sensing coils, the magnet will hunt to magnetic north and the movement involved in hunting will generate the signals conductively.

The microprocessor can be used to calculate the point about which hunting is taking place.

The invention will be further described with reference to the accompanying drawing, of which the single figure is a diagrammatic sectional view showing a preferred form of compass according to the invention.

The drawing shows magnet 1, with its ends shaped differently so that different signals are sensed at the north and south ends of it. The magnet 1 is embedded in a spherical block 2 of non-magnetic material and this block 2 is suspended in appropriate fluid 3 within a housing 4, also of spherical shape. The housing 4 has embedded therein a set of sensing coils 5 spaced over its whoie surface. Only a few such sensing coils are shown. It will be understood that the housing 4 will be located where it can be used to allow the magnet 1 to seek magnetic north and as the magnet 1 hunts for magnetic north, signals will be electromagnetically induced in the coils 5.

The magnitude of these signals will depend on the proximity to the magnet and also on the speed of movement of the magnet and by transmitting these signals derived from them, to a suitably programmed microprocessor, the position of magnetic north about which the magnet is hunting, can be accurately ascertained.

It will also be understood that instead of sensing coils, some sort of light sensing device may be used in conjunction with fibre optic light sources associated with the magnet. Also, although the spherical shape has been described as preferred for the block 2 and the housing 4, other rounded shapes such as extended spheres or ellipsoidal forms can be used.

It will be understood that if the compass is used in connection with a drill stack, it can be mounted in a drill tube so that the direction of the drill tube in relation to magnetic north can easily be ascertained. With suitable telemetry, such as that described in may above-mentioned copending application, the time required to ascertain magnetic north is only a few seconds. It will thus be economic to check for any deviation from a predetermined course at short time intervals, thus avoiding the need for excessive corrective action.

Various modifications may be made within the scope of the invention.

Claims

1. A remotely usable compass comprising a magnet suspended in a housing with freedom to seek magnetic north, a series of sensing device in the housing to generate signals dependent on the position or movement of the magnet, and means for processing the signals to ascertain the position of the magnet relative to the housing.

2. A compass as claimed in claim 1, in which the sensing devices are sensing coils.

3. A compass as claimed in claim 1 or 2, in which the magnet is embedded in a block or mass of non-magnetic material and the block or mass is suspended by suitable liquid in the housing, which is of similar shape to the block or mass.

4. A compass as claimed in claim 3, in which the block or mass and the housing are each in the form of an extended sphere.

5. A remotely usable compass substantially as hereinbefore described with reference to the accompanying drawing.

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

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Remote compass This invention relates to compasses which may be used with telemetry equipment to enable the deviation from magnetic north to be determined from a remote point. The remote compass is particularly designed to be used in a drilling rig in accordance with my copending application No. 8134337, filed simultaneously herewith and entitled "Drilling Equipment and method". However, its use is not to be regarded as restricted to such an application. According to the invention, there is provided a remotely usable compass comprising a magnet suspended in a housing with freedom to seek magnetic north, a series of sensing devices in the housing to generate signals dependent on the position or movement of the magnet, and means for processing the signals to ascertain the position of the magnet relative to the housing. The shape of the magnet will provide differentiation between north and south. The sensing devices are preferably sensing coils but light sensing devices, associated with fibre optics, may alternatively be used. The signals from the sensing device may be processed in a microprocessor to ascertain the position of the magnet in relation to the housing. In the case of sensing coils, the magnet will hunt to magnetic north and the movement involved in hunting will generate the signals conductively. The microprocessor can be used to calculate the point about which hunting is taking place. The invention will be further described with reference to the accompanying drawing, of which the single figure is a diagrammatic sectional view showing a preferred form of compass according to the invention. The drawing shows magnet 1, with its ends shaped differently so that different signals are sensed at the north and south ends of it. The magnet 1 is embedded in a spherical block 2 of non-magnetic material and this block 2 is suspended in appropriate fluid 3 within a housing 4, also of spherical shape. The housing 4 has embedded therein a set of sensing coils 5 spaced over its whoie surface. Only a few such sensing coils are shown. It will be understood that the housing 4 will be located where it can be used to allow the magnet 1 to seek magnetic north and as the magnet 1 hunts for magnetic north, signals will be electromagnetically induced in the coils 5. The magnitude of these signals will depend on the proximity to the magnet and also on the speed of movement of the magnet and by transmitting these signals derived from them, to a suitably programmed microprocessor, the position of magnetic north about which the magnet is hunting, can be accurately ascertained. It will also be understood that instead of sensing coils, some sort of light sensing device may be used in conjunction with fibre optic light sources associated with the magnet. Also, although the spherical shape has been described as preferred for the block 2 and the housing 4, other rounded shapes such as extended spheres or ellipsoidal forms can be used. It will be understood that if the compass is used in connection with a drill stack, it can be mounted in a drill tube so that the direction of the drill tube in relation to magnetic north can easily be ascertained. With suitable telemetry, such as that described in may above-mentioned copending application, the time required to ascertain magnetic north is only a few seconds. It will thus be economic to check for any deviation from a predetermined course at short time intervals, thus avoiding the need for excessive corrective action. Various modifications may be made within the scope of the invention. Claims

1. A remotely usable compass comprising a magnet suspended in a housing with freedom to seek magnetic north, a series of sensing device in the housing to generate signals dependent on the position or movement of the magnet, and means for processing the signals to ascertain the position of the magnet relative to the housing.

2. A compass as claimed in claim 1, in which the sensing devices are sensing coils.

3. A compass as claimed in claim 1 or 2, in which the magnet is embedded in a block or mass of non-magnetic material and the block or mass is suspended by suitable liquid in the housing, which is of similar shape to the block or mass.

4. A compass as claimed in claim 3, in which the block or mass and the housing are each in the form of an extended sphere.

5. A remotely usable compass substantially as hereinbefore described with reference to the accompanying drawing.