Protective device for liquid- or gas-filled electrical appliances

Description

The conditions need to be checked, which, in addition to causing operational disruptions, also leads to assembly difficulties. In principle, it is of course possible to circumvent these difficulties if the protective device is mounted on the outside of the container being monitored. The device is arranged in this way, since the device responds to pressure changes. Such an arrangement is particularly useful if already Devices already in operation can be retrofitted with protective devices. One could therefore consider connecting the protective device, for example, via the... The standardized oil drain plug of the device or any other connection fitting should be used. However, this would not be possible without oil loss and would have led to... The condition is that the converter, transformer, or similar device would have to be taken out of service beforehand. These difficulties can be avoided according to the invention by such an encapsulation, the protective device, which protects the external connection. The connection can be made to a nozzle without oil loss and in any position on the container of the apparatus to be protected. Since the interior The encapsulation is filled with the cooling or insulating fluid of the apparatus to be protected, resulting in certain response times. The same conditions apply as if the protective device were located directly inside the container. That is, if an event occurs If damage occurs inside the boiler and a rapid pressure increase takes place, the protective device responds immediately because of the sudden pressure change in the inside the apparatus vessel, it continues on all sides and immediately causes the membrane of the protective device to oscillate. On the other hand, it can The protective device can be connected without switching off the devices to be monitored, and in any position regardless of the Location of the equipment. Since the capsule also provides protection against mechanical damage to the actual protective device, there is no need for further measures. special protective caps, such as those used in the protective devices known to date that are arranged directly in the insulating fluid of the apparatus vessel were required. Regarding the arrangement on the apparatus container, the connection directly to the one on the apparatus housing proves to be necessary anyway. Existing and standardized oil drain or filler necks are particularly advantageous. An embodiment of the invention is described below. The application is explained in more detail for use with a measuring transducer. As can be seen from Fig. 1 of the schematic drawing, which is limited to what is essential within the scope of the invention, The housing 10, which contains the active part of the converter (not shown) and is made, for example, of welded sheet steel, has its lower area has a standardized oil drain fitting 11, which is fitted in a known manner with an internal thread 12 and an external thread 13. and is provided with oil outlet openings 14, 15. Reference numeral 16 designates a threaded plug, adjustable in the connecting nozzle, serving as a control element. which is screwed into the nozzle 11 in case the protective device 17 is not yet connected and closes the oil outlet openings. The oil outlet openings 14, 15 do not necessarily have to be located in the connection fitting; corresponding channels can just as well be used. The threaded plug 16 itself is designed to accommodate a wrench, for example a square one, with a corresponding recess! 18. The end cap, labeled 19 in the illustrated example, must be attached before connecting the protective device. The fitting 11 is screwed on, thus completing the arrangement of oil drain fitting — threaded plug to the outside. When connecting the capsule 20, the actual protective device 21 and the key 23 containing a square 22 are The protective device is now installed as follows: After unscrewing the sealing cap 19 from the oil drain fitting II, a flange 24 is placed on the fitting. A hexagonal nut 25 with a flange was attached and screwed on, which is made possible by the external thread 13. Since the threaded plug Now that it is accessible, the entire protective device can be placed on the aforementioned plug using the key 23, which also serves as a guide. The square 22 then enters the corresponding recess 18 of the plug. The plug has bores for receiving... The connection area of ​​the capsule 20, equipped with fastening screws, comes into contact with the flat surfaces of the nut 25, thereby achieving a good A seal 26 is provided between the flat side of the nut and the corresponding end face of the capsule 20. This seal acts as an abutment. The screws 27 (see Fig. 2) required for fastening the housing 20 are now inserted into the flange 24, and the screwing can be carried out. The flange can be equipped with slot-shaped recesses 28 for inserting the fastening screws. After the screw connection has been made, the threaded plug 16 is unscrewed from the oil drain fitting 11 using the wrench 23, which is guided gas- and liquid-tight within the capsule assembly, until the openings 14 and 15 are exposed and the capsule chamber 29 can fill with oil. Since the openings 14 and 15 are of different sizes and the threaded plug can also be completely unscrewed from the connection fitting, the oil supply to the capsule attached to the connection fitting can be regulated externally. This means that, depending on the position of the threaded plug, one or more channels to the inside of the capsule are opened or closed. The air displaced by the oil during filling can escape through a recess 30 in the appropriately loosened sealing screw 31. The recess 32 in the housing wall 20, which serves to receive the cylindrical bolt, is f

Claims

A stuffing box 33 is sealed liquid-tight. Stops 34 on the cylindrical bolt prevent the bolt from falling out. After After the protective device has been connected and filled, the closure cap 19 is placed onto the threaded reinforcement 35 of the The capsule wall is screwed on. The capsule is fastened in such a way that it allows the capsule to rotate around the axis of the connecting nozzle. The above-described embodiment of the protective device and its connection to the oil drain plug thus requires practically no additional effort and allows for easy disassembly or replacement without oil loss, i.e., without damaging the part to be protected. The device must be switched off. Another advantage is that there are no installation requirements to observe regarding whether the connection is horizontal, vertical, or in a... otherwise appropriate location. The mode of operation of the actual protective device, of which only the metallic aneroid body 36 is shown, is based in a known manner. that, in the event of rapidly increasing pressure in the interior of container 10 of the converter to be protected, a [missing information] arranged to the right of the aneroid body, The undrawn air-filled chamber of the protective device, with its essentially constant volume, initially retains its pressure, so that both A pressure difference arises on the sides of a membrane (also not shown), causing the membrane to oscillate, which in turn... The operating circuit for the warning or shutdown process is closed. If the pressure in the converter vessel increases slowly, the aneroid body 36 is compressed, thus reducing its volume. The interior However, this body is connected to the chamber containing the membrane (not shown) via a compensating bore, so that also In this chamber, a corresponding pressure increase occurs, and practically the same pressure prevails on both sides of the membrane, so that no This triggers the warning or shutdown process. Fig. 2 shows the view of the protective device shown in cross-section in Fig. 1 along the section line AB. Patent claims:

1. Protective device for liquid- or gas-filled, in particular oil-insulated, electrical appliances, in which the control of the warning or The shutdown process is carried out with the aid of a body of variable volume, and according to patent 853 924, two air- or gas-filled and by a The narrow compensating bore contains interconnected chambers, one of which has a substantially constant volume and the other a characterized by having a variable volume, and in which the warning or shutdown process is controlled by a freely movable membrane. through such encapsulation, which allows external connection to a connection nozzle without oil loss and in any position.

2. Protective device according to claim 1, characterized in that the oil supply to the capsule attached to the connection nozzle is provided from the outside. It is adjustable.

3. Protective device according to claims 1 and 2, characterized in that the controlling element is an adjustable connecting piece accessible from the outside. Threaded plugs are used.

4. Protective device according to claims 1 to 3, characterized in that one or more channels are provided depending on the position of the threaded plug. to be released or closed to the capsule interior.

5. Protective device according to claims 1 to 4, characterized in that the capsule is provided with a vent screw.

6. Protective device according to claims 1 to 5, characterized in that the fastening of the capsule involves a rotation about the axis of the connection. allows for trimming. This includes 1 sheet of drawings. © 609 658 / 171 10.56 ' (609 863 4. 57)