GB2342781A

GB2342781A - Encapsulated device

Info

Publication number: GB2342781A
Application number: GB9922592A
Authority: GB
Inventors: Wolfgang Heinz; Dieter Maisch
Original assignee: IMI Norgren Herion Fluidtronic GmbH and Co KG
Current assignee: Norgren GmbH
Priority date: 1998-09-23
Filing date: 1999-09-23
Publication date: 2000-04-19
Anticipated expiration: 2019-09-23
Also published as: GB2342781B; GB9922592D0; DE19843522A1; CH694391A5; DE19843522B4

Abstract

An encapsulated device comprises a coil (20) incorporated in a casing (10). The coil (20) is embedded in a sealing compound (50), which serves to hold the coil (20) in position, isolate the coil (20) electrically and protect the coil (20) from environmental influences. The casing (10) is a pipe of substantially rectangular section cut to a predeterminable length. The casing is closed at both ends. For the sake of completeness the axis (20<SP>1</SP>) of the coil (20) is perpendicular to the longitudinal axis of the pipe. The device may be an explosion-proof electromagnet.

Description

2342781 I Encapsulated device The present invention relates to an

encapsulated device, and in particular to an explosion-proof electromagnet, comprising a casing containing a coil embedded in a sealing compound. The sealing compound holds the coil in position, as well as isolating the coil electrically and protecting the coil from environmental influences. The casing is a pipe of substantially rectangular section cut to a pre-determined length. The pipe is closed at both ends.

A device of this type is disclosed, for example, in German utility model 90 03 343 or in US 5,138,292.

Devices of this type usually use metal casings, which are usually manufactured using a casting, drawing or welding technique. In this application, stainless-steel casings in particular have proved to be problematic, as they necessitate expensive processing.

An object of the invention is to provide an encapsulated device of the type mentioned above which is simple and inexpensive to manufacture.

The invention provides an encapsulated device as claimed in Claim 1.

2 The use of a pipe of substantially rectangular section for the casing has the advantage of being manufactured by the running metre and of being matchable to the size of the casing by simply cutting to length.

Costly manufacture of the casing can therefore be dispensed with.

In a preferred embodiment the pipe is closed at at least one end by the sealing compound. In this case a cover element can be dispensed with at this end. In this arrangement the sealing compound, preferably a cast resin, e.g. EP, forms a seal which also satisfies the high requirements of an explosion-protected magnet of protection types EExm, EExe or EExi in accordance with EN 50 014 ff.

In a further embodiment the pipe is closed by a plate mounted in the pipe by welding, soldering or compression. The pipe may also be closed at at least one end by a cover held by means of a threaded bolt embedded in the sealing compound.

An iron circuit is preferably embedded in the sealing compound.

The pipe itself may be made of a wide range of materials. In a preferred embodiment the pipe is made of stainless steel.

In a ffirther embodiment the pipe is made of a ferromagnetic steel. In this case the pipe casing may simultaneously be used as a magnetic circuit.

3 Insofar as the alignment of the coil and the iron circuit are concerned, a wide range of embodiments are conceivable. The arrangement of the axis of the coil perpendicular to the longitudinal axis of the pipe results in a compact construction.

Other advantages and features of the invention are described below.

An embodiment of the invention is shown in the accompanying drawings, in which Fig. I is a schematic perspective view of an encapsulated device according to the invention,and Fig. 2 is a sectional view of the encapsulated device of Fig. 1.

Figures I and 2 show an encapsulated device in the form of an explosionproof electromagnet comprising a pipe-shaped casing 10 of substantially rectangular section which, for example, may be made of steel, in particular a ferromagnetic alloy.

A bore 12 is disposed within the pipe-shaped casing 10, as is known per se, essentially perpendicularly to the axis of the casing. The bore 12 is surrounded by a ring-shaped coil 20, and by a saddle-shaped iron circuit 30. An axis 201 of the coil 20 is perpendicular to the longitudinal axis of the casing. The coil 20, iron circuit 30 and other structural elements 40 are enclosed in a sealing compound 50 which closes the casing at an end I I so as to be flush with the casing. As a result of this a cover element, 4 normally mounted in the casing, can be dispensed with, thus simplifying assembly and reducing the manufacturing costs (cf. Fig. 2).

In Fig. 2, the sealing compound 50 ends in the interior of the casing. Connecting elements 22 for the coil 20 protrude from the sealing compound 50 into a hollow space 14 of the casing. Leads (not shown) are attached to the connecting elements 22. The leads are guided via a pipe-shaped connecting piece 15 into the interior of the hollow space 14. The casing is closed at its hollow space-closing end face 13 by, for example, a deepdrawn cover element 60, which is mounted by means- of a screw 61 on a threaded bolt 70 embedded in the sealing compound 50. A sealing element 80 is disposed between the cover element 60 and the casing 10. It is selfevident that a cover element 60 such as this can be dispensed with if the whole interior space of the pipeshaped casing 10 is filled with the sealing compound 50. In this case the electrical connections, that is the connecting wires which are mounted on the connecting elements 22, are then also embedded in the sealing compound 50.

If the casing is made of a ferromagnetic steel it can simultaneously be used as a magnetic circuit. The iron circuit 30 can be dispensed with in this case.

It is also self-evident that, on its face turned towards the coil, the casing may also be closed by a cover element similar to the cover element 60, with which it is closed on its face turned away from the coil 20. This cover element can be permanently mounted in the pipe-shaped casing 10 by compression or welding.

Claims

Claims:

1. An encapsulated device comprising a casing containing a coil embedded in a sealing compound, the sealing compound holding the coil in position, isolating the coil electrically and protecting the coil from environmental influences, the casing being a pipe of substantially rectangular section cut to a pre-deten-nined length and closed at both ends, wherein the axis of the coil is perpendicular to the longitudinal axis of the pipe.

2. An encapsulated device, as claimed in Claim 1, wherein the device is an explosionproof electromagnet.

3. An encapsulated device as claimed in Claim I or 2, wherein the pipe is closed at at least one end by the sealing compound.

4. An encapsulated device as claimed in Claim 1, 2 or 3, wherein the pipe is closed by a plate mounted in the pipe by welding, soldering or compression.

5. An encapsulated device as claimed in any one of Claims I to 4, wherein the pipe is closed at at least one end by a cover held by means of a threaded bolt embedded in the sealing compound.

6 6. An encapsulated device as claimed in any one of Claims I to 5, wherein the coil is associated with an iron circuit embedded in the sealing compound.

7. An encapsulated device as claimed in any one of Claims I to 6, wherein the pipe is made of stainless steel.

8. An encapsulated device as claimed in any one of Claims I to 5, wherein the pipe is made of a ferromagnetic steel.

9. An encapsulated device substantially as herein described with reference to the accompanying drawings.