GB1562513A

GB1562513A - X-ray generator

Info

Publication number: GB1562513A
Application number: GB34212/76A
Authority: GB
Original assignee: ASS IND Ltd; Philips Electronic and Associated Industries Ltd
Current assignee: ASS IND Ltd; Philips Electronics UK Ltd
Priority date: 1975-08-20
Filing date: 1976-08-17
Publication date: 1980-03-12
Also published as: DE2537019B2; FR2321816A1; DE2537019A1; BE845299A; FR2321816B1; JPS5225587A

Description

(54) X-RAY GENERATOR (71) We, PHILIPS ELEcTRoNIc AND ASSOCIATED INDUSTRIES lIMITED of Abacus House, 33 Gutter Lane, London, EC2V 8AH, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to a device comprising an X-ray source and a high-voltage generator, in which the X-ray source and the high-voltage generator are accommodated in respective housings, and such a device will be referred to herein as a device of the kind referred to.

In known devices of this kind, the housing of the high-voltage generator and the housing of the X-ray source are usually earthed, and the high voltage is applied from the high-voltage generator to the X-ray source via one or two high-voltage cables. High-voltage cables of this kind are comparatively thick, notably in the case ofhigh tube voltages, and hence they are not very flexible, so that the freedom of movement of the X-ray source is impeded.

Also known are the so-termed singleenclosure generators. Therein, the X-ray tube and the high-voltage generator are accommodated in a common housing. The freedom of movement of such a singleenclosure generator is substantially unaffected by the voltage supply cable, because use can then be made of a low-voltage cable which may be flexible.

This construction has a drawback, however, in that the replacement of an X-ray tube can be expensive, because all parts contained in the enclosure must be reimpregnated and dried again (in the case where oil is used as the insulation medium) or must be evacuated again (in the case where gas is used as the insulation medium).

It is an object of the invention to provide a device of the kind referred to in which the freedom of movement is substantially unimpeded by the voltage supply cable and in which the X-ray tube can be readily replaced.

According to the invention there is provided a device of the kind referred to, wherein the respective housings of the X-ray source and of the high-voltage generator each include an insulator portion which supports high-voltage conductors, and which together constitute a high-voltage plug connection. When the term "X-ray tube" is used as an alternative for "X-ray source", an X-ray tube is meant which comprises a metal envelope which forms part of the housing of the source, and at least one high-voltage insulator portion which is connected thereto and also forms part of the source housing as that - after combination with the high-voltage generator housing - further source housing means are not required.

A high-voltage plug connection between the respective housings of the X-ray source and the high-voltage generator, can be constructed in various ways. The X-ray source or the Xray tube housing can comprise a tapered insulator portion for which the high-voltage generator housing is provided with a dimensionally corresponding recess. However, the plug connection can alternatively be constructed in the reverse manner, the X-ray source housing or tube then including a tapered recess in the insulator portion thereof, and the insulator portion of the high-voltage generator is tapered in the direction of the end thereof which is remote from the generator. The latter embodiment can be advantageously used when the Xray tube comprises a metal envelope in which the high-voltage carrying electrode is connected to a conductor supported by a conical insulator which is provided with a conical recess at the end thereof remote from the tube interior.

An embodiment of a device in accordance with the invention will now be described by way of example, with reference to the accompanying drawing, the single figure of which shows diagrammatically an embodiment in the form of an X-ray source for dental examination which includes a conical insulator plug as high-voltage plug.

Referring to the drawing, the device shown comprises an X-ray tube I, a protective housing 2 for the X-ray tube which constitutes the X-ray source housing in conjunction with the exposed envelope of the X-ray tube, a highvoltage generator 3 which includes a voltage multiplier cascade ciruit 9, and a transformer 4.

The X-ray tube is of a one-pole type commonly used for dental examination, i.e. the anode operates at earth potential and the cathode operates at a (negative) high-voltage.

The X-ray tube 1 can be secured, by means of a nut 5, to the protective tube housing 2 which is provided with a threaded metal collar 6 for this purpose. The metal collar 6 forms, in conjunction with an insulating container 7, formed of a suitable housing grade of epoxy resin and manufactured, for example, under the name of ARALDITE (Registered Trade Mark), a protective tube housing and is connected thereto in an oiltight manner.

Prior to the fitting of the X-ray tube, the protective housing must be filled with oil. A lower end 12 of the insulating container 7 is tapered. The insulating container 7 accommodates high-voltage conductors in the form of spring contacts 8.

The high-voltage generator comprises a cascade unit 9 cast in epoxy resin. A housing block 15 formed by the casting material includes a recess 10 in which a rubber sleeve 11 is fitted in this embodiment. The inner dimensions of the rubber sleeve 11 and the outer dimensions of the lower portion 12 of the insulating container 7 match, so that no air will be trapped in the recess presented by the rubber seeve 11 when the lower portion 12 is pressed in. The lower portion 12 of the container 7, being made of ARALDITE (Registered Trade Mark) for insulation purposes, thus acts as a high-voltage plug. The spring contacts 8 contact the contact plates 14 after introduction into the recess 13, the contact plates 14 being provided on the head face of the conical recess, with the result that the high-voltage is applied from the cascade unit 9 to the X-ray tube 1 via the contact plates 14 and the spring contacts 8.

The insulated container 7 and the epoxy resin block 15 each include a shoulder 16, 17, respectively, in order to retain clamping rings 18 and 19 which are to be fitted after the plug 12 has been introduced into the recess 13.

The drawing shows only part of these rings.

The plug 12 can be pressed into the recess 13 with the required force by means of tension bolts 20, only one of which is shown in the drawing.

The cascade unit 9 is powered by the transformer 4, the secondary coil of which is also encapsulated in an epoxy-resin block 21. This transformer can be mounted 23 on a face of the block 15 by means of a bracket 22.

After assembly, during which a further tubular external housing which envelops the container 7 and the block 15, can also be fitted if desired, the device is comparatively readily movable, because voltage supply is effected via a low-voltage cable connected to the transformer 4. In the case of a defective X-ray tube, this tube can be replaced by the removal of the protective tube housing 2 and the mounting of a new protective tube housing with a new X-ray tube. This replacement can be effected at the site of use, because repair of the defect - unlike a corresponding repair to a singleenclosure generators -- does not involve interference with the high-voltage generator. Consequently, reimpregnation etc is not required.

The description of the embodiment is based on a single-pole X-ray tube. In the case of a two-pole X-ray tube, in which both the anode and the cathode carry high-voltage potentials relative to earth, the invention can be realized by constructing the protective tube housing or the X-ray tube to form a plug on opposite ends and by using a second high-voltage generator which includes a recess for receiving the plug and which serves for generating a voltage of opposite polarity. If the X-ray tube comprises a metal envelope in which the highvoltage electrodes are mounted on conical insulators the outer ends of which are provided with conical recesses, the two high-voltage generators should each be constructed to form a high-voltage plug at one end.

WHAT WE CLAIM 1S: 1. A device comprising an X-ray source and a high-voltage generator in which the X-ray source and the high-voltage generator are accommodated in respective housings, wherein the respective housings of the X-ray source and the high-voltage generator each include an insulator portion which supports high-voltage conductors and which together constitute a high-voltage plug connection.

2. A device as claimed in Claim 1, wherein said insulator portion of the housing of the X-ray source is tapered towards an end which is remote from the X-ray source, the insulator portion of the housing of the high-voltage generator including a matching recess.

3. A device as claimed in Claim 1, wherein the housing of the X-ray source includes a tapered recess, said insulator portion of the housing of the high-voltage generator being constructed to form a plug.

4. A device as claimed in any one of the

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. which is provided with a conical recess at the end thereof remote from the tube interior. An embodiment of a device in accordance with the invention will now be described by way of example, with reference to the accompanying drawing, the single figure of which shows diagrammatically an embodiment in the form of an X-ray source for dental examination which includes a conical insulator plug as high-voltage plug. Referring to the drawing, the device shown comprises an X-ray tube I, a protective housing 2 for the X-ray tube which constitutes the X-ray source housing in conjunction with the exposed envelope of the X-ray tube, a highvoltage generator 3 which includes a voltage multiplier cascade ciruit 9, and a transformer 4. The X-ray tube is of a one-pole type commonly used for dental examination, i.e. the anode operates at earth potential and the cathode operates at a (negative) high-voltage. The X-ray tube 1 can be secured, by means of a nut 5, to the protective tube housing 2 which is provided with a threaded metal collar 6 for this purpose. The metal collar 6 forms, in conjunction with an insulating container 7, formed of a suitable housing grade of epoxy resin and manufactured, for example, under the name of ARALDITE (Registered Trade Mark), a protective tube housing and is connected thereto in an oiltight manner. Prior to the fitting of the X-ray tube, the protective housing must be filled with oil. A lower end 12 of the insulating container 7 is tapered. The insulating container 7 accommodates high-voltage conductors in the form of spring contacts 8. The high-voltage generator comprises a cascade unit 9 cast in epoxy resin. A housing block 15 formed by the casting material includes a recess 10 in which a rubber sleeve 11 is fitted in this embodiment. The inner dimensions of the rubber sleeve 11 and the outer dimensions of the lower portion 12 of the insulating container 7 match, so that no air will be trapped in the recess presented by the rubber seeve 11 when the lower portion 12 is pressed in. The lower portion 12 of the container 7, being made of ARALDITE (Registered Trade Mark) for insulation purposes, thus acts as a high-voltage plug. The spring contacts 8 contact the contact plates 14 after introduction into the recess 13, the contact plates 14 being provided on the head face of the conical recess, with the result that the high-voltage is applied from the cascade unit 9 to the X-ray tube 1 via the contact plates 14 and the spring contacts 8. The insulated container 7 and the epoxy resin block 15 each include a shoulder 16, 17, respectively, in order to retain clamping rings 18 and 19 which are to be fitted after the plug 12 has been introduced into the recess 13. The drawing shows only part of these rings. The plug 12 can be pressed into the recess 13 with the required force by means of tension bolts 20, only one of which is shown in the drawing. The cascade unit 9 is powered by the transformer 4, the secondary coil of which is also encapsulated in an epoxy-resin block 21. This transformer can be mounted 23 on a face of the block 15 by means of a bracket 22. After assembly, during which a further tubular external housing which envelops the container 7 and the block 15, can also be fitted if desired, the device is comparatively readily movable, because voltage supply is effected via a low-voltage cable connected to the transformer 4. In the case of a defective X-ray tube, this tube can be replaced by the removal of the protective tube housing 2 and the mounting of a new protective tube housing with a new X-ray tube. This replacement can be effected at the site of use, because repair of the defect - unlike a corresponding repair to a singleenclosure generators -- does not involve interference with the high-voltage generator. Consequently, reimpregnation etc is not required. The description of the embodiment is based on a single-pole X-ray tube. In the case of a two-pole X-ray tube, in which both the anode and the cathode carry high-voltage potentials relative to earth, the invention can be realized by constructing the protective tube housing or the X-ray tube to form a plug on opposite ends and by using a second high-voltage generator which includes a recess for receiving the plug and which serves for generating a voltage of opposite polarity. If the X-ray tube comprises a metal envelope in which the highvoltage electrodes are mounted on conical insulators the outer ends of which are provided with conical recesses, the two high-voltage generators should each be constructed to form a high-voltage plug at one end. WHAT WE CLAIM 1S:

1. A device comprising an X-ray source and a high-voltage generator in which the X-ray source and the high-voltage generator are accommodated in respective housings, wherein the respective housings of the X-ray source and the high-voltage generator each include an insulator portion which supports high-voltage conductors and which together constitute a high-voltage plug connection.

4. A device as claimed in any one of the

preceding claims, in which the X-ray source comprises an X-ray tube having two electrodes which carry a high-voltage potential with respect to earth during operation, wherein there is provided a second high-voltage generator accommodated in a turther housing including an insulator portion which supports a highvoltage conductor, and arranged to form a plug connection in conjunction with a correspondingly shaped further insulator portion of the housing of the X-ray source.

5. A device as claimed in any one of the preceding claims, wherein a suitably shaped rubber sleeve is provided between the cooperating insulator portions of the X-ray source housing and of the high-voltage generator housing.

6. A device of the kind referred to, substantially as herein described with reference to the accompanying drawing.