Patent Application
20220293366
The invention relates to a separating wall for dividing a heating volume of a power circuit, in particular of a self-compressing power circuit, and to a method for producing a separating wall of this type.
A power circuit serves for opening and closing a current path, in particular so as to protect against overload currents and short circuit currents. A power circuit typically has two arcing contact elements which when opening and closing the current path are moved relative to one another and between which an arc is ignited in an arc space when the current path is opened.
A self-compressing power circuit, also referred to as a sulfur hexafluoride circuit breaker, is filled with an extinguisher gas, for example with sulfur hexafluoride, and utilizes part of the energy released in the arc for building up an extinguishing pressure for extinguishing the arc, as a result of which said self-compressing power circuit requires less operating energy in comparison to dual-nozzle power circuits, for example. When the current path is opened, an arc is ignited between the arc contacts, said arc when exceeding a geometry-specific minimum amperage completely closing an isolating nozzle constriction. The arc space by way of a heating duct is connected to a separate heating volume in which the extinguishing pressure is generated as a result of hot gas flowing in from the arc space and said hot gas mixing with the cold gas in the heating volume.
With a view to a more effective buildup of extinguishing pressure, the heating volume in a suitable manner is often separated into two sub-volumes. In the case of low currents (operating currents, partial loads), the smaller of the sub-volumes is predominantly utilized for building up the extinguishing pressure, and in the case of high currents, the entire heating volume is utilized for building up of the extinguishing pressure.
In the prior art, the separation of the heating volume today takes place by way of a so-called separating cylinder which connects the two sub-volumes by way of permanent openings (for example, simple bores).
The invention is based on the object of enabling a heating volume of a power circuit to be divided into two sub-volumes in an improved manner.
This object is achieved according to the invention by a separating wall having the features of claim 1, by a method for producing a separating wall of this type having the features of claim 10, and by a power circuit having the features of claim 12.
Advantageous design embodiments of the invention are the subject matter of the dependent claims.
A separating wall according to the invention for dividing a heating volume of a power circuit into a first sub-volume and a second sub-volume comprises at least one wall opening which enables a gas flow between the sub-volumes, and has an aerodynamically effective opening area which is a function of a pressure differential between a pressure in the first sub-volume and a pressure in the second sub-volume.
The aerodynamically effective opening area of a wall opening here is understood to be an effective cross-sectional area of the wall opening which is defined, for example, as a product of a geometric (actual) opening area of the wall opening and an opening-specific outflow factor. The outflow factor of a wall opening takes into account the flow resistances such as the shaping of the wall opening, installations in the wall opening or the type and/or frequency of the change of direction of a flow through the wall opening.
A separating wall according to the invention enables the heating gas flowing from the arc space into the heating volume to be divided into two sub-volumes of the heating volume as a function of a pressure of the heating gas through special wall openings in the separating wall, the aerodynamically effective opening area of said wall openings being a function of the pressure differential between the sub-volumes. As a result thereof, dividing the heating gas between the two sub-volumes is enabled so as to take into account the pressure of the heating gas and the intensity of the arc. For example, it can be achieved that the heating gas at relatively small pressure differentials makes its way substantially only into a first of the two sub-volumes, such that no losses or only minor losses in terms of heating gas arise in the first sub-volume, as a result of which the build-up of extinguishing pressure in the first sub-volume, and thus the extinguishing capability is improved. As the pressure differential increases, more and more heating gas makes its way from the first sub-volume into the second sub-volume, wherein the flow from the first sub-volume into the second sub-volume is a function of the pressure differential as well as of the aerodynamically effective opening area of the at least one wall opening. As opposed to wall openings which have aerodynamically effective opening areas that are not a function of pressure, a flow of the extinguishing gas can thus be effected from the first sub-volume into the second sub-volume, said flow being a function of the pressure differential directly as well as indirectly by way of the aerodynamically effective opening areas of the wall openings. This enables the extinguishing gas pressure in the heating volume to be built up in a manner readily adaptable to the intensity of the arc.
In one embodiment, the separating wall comprises at least one opening closure by way of which a wall opening is able to be at least partially closed, the opening state of said opening closure being a function of the pressure differential.
In one further embodiment, at least one opening closure, by way of a spring element, by which a restoring force as a function of the pressure differential is able to be exerted on the opening closure, is coupled to a separating wall region of the separating wall which is adjacent to the wall opening that is able to be at least partially closed by the opening closure.
In one further embodiment, the spring element comprises a spring or a valve flap made of metal, or at least one correspondingly resilient plastics material part.
In one further embodiment, at least one opening closure by way of an elastic connection region is connected to a separating wall region of the separating wall which is adjacent to the wall opening that is able to be at least partially closed by the opening closure.
In one further embodiment, at least one wall opening is configured as a meandering flow duct between the sub-volumes.
In one further embodiment, at least one meandering flow duct has a flow resistance element which by way of a gas flow flowing in the flow duct is able to be elastically deflected.
In one further embodiment, the separating wall furthermore has at least one wall reinforcement which is made from a reinforcement material which is of a greater strength than the surrounding material in which the wall reinforcement is embedded.
Such a wall reinforcement or insert stabilizes the construction and enables savings in terms of material, optimization in terms of space, more space for the extinguishing gas, and an effective enlargement of the heating volume.
In one further embodiment, the separating wall has a substantially hollow-cylindrical shape, thus is formed as separating cylinder.
In one further embodiment, at least external surfaces of the separating wall are made from polytetrafluoroethylene.
According to one aspect of the present invention, the separating wall is produced by means of 3-D printing.
In this way, shapes can be implemented which cannot be produced by conventional technology.
In one embodiment, the separating wall is printed onto a carrier component. In this way, the number of individual parts is reduced and the assembly is facilitated.
The invention furthermore relates to a power circuit having a separating wall as described above, wherein the separating wall divides a heating volume into two sub-volumes.
The properties, features and advantages of this invention described above, and the manner in which said properties, features and advantages are achieved, will become clearer and more evident in the context of the description hereunder of exemplary embodiments which are explained in more detail in conjunction with the drawings, in which:
Equivalent parts are provided with the same reference signs in the figures.
The power circuit 1 can be configured as a self-compressing power circuit which converts the energy released in the arc for the purpose of building up extinguishing pressure, as a result of which said self-compressing power circuit requires less operating energy in comparison to a dual-nozzle power circuit. During a switching-off procedure, that is to say when opening the current path, an arc is ignited between the arc contact elements, said arc when exceeding a geometry-specific minimum amperage completely closing an isolating nozzle constriction. The arc space 2 by way of a heating duct 4 is connected to a separate heating volume 3 in which an extinguishing pressure is generated by hot gas flowing in from the arc space 2 and said hot gas mixing with the cold gas in the heating volume 3. The arrows indicate directions of a gas flow H of the gas. The arc space 2 and the heating volume 3 are configured so as to be substantially rotationally symmetrical in relation to a rotation axis A, the arc contact elements being moved relative to one another along said rotation axis A. The rotation axis A here runs through the arc space 2, and the heating volume 3 is a volume which is disposed about the rotation axis A so as to be spaced apart from said rotation axis A in a radial direction r.
With a view to a more effective build-up of extinguishing pressure, the heating volume 3 in a suitable manner is separated into two sub-volumes 3.1, 3.2. In the case of low currents (operating currents, partial loads) a first sub-volume 3.1 can be primarily used for building up extinguishing pressure, and in the case of high currents the entire heating volume 3 can be utilized for building up extinguishing pressure.
The separation of the heating volume 3 in the prior art takes place by a separating wall 5, in particular a so-called separating cylinder, which has permanent wall openings 6 (for example, simple bores) which connect the two sub-volumes 3.1, 3.2.
Embodiments of the separating wall 5 according to the invention in the region of wall openings 6 are shown in
A separating wall 5 according to the invention can furthermore have at least one wall reinforcement 12 which is made from a reinforcement material which is of a greater strength than the surrounding material in which the wall reinforcement is embedded. The surrounding material is, for example, polytetrafluoroethylene and forms in particular the external surfaces of the separating wall. The surrounding material and the reinforcement material are electrically non-conducting materials.
The separating wall 5 has a substantially hollow-cylindrical shape, the cylinder axis thereof coinciding with the rotation axis A.
The opening closure 7, by way of a spring element 8, by which a restoring force which is a function of the pressure differential is able to be exerted on the opening closure 7, is coupled to a separating wall region of the separating wall 5 which is adjacent to the wall opening 6 that is able to be at least partially closed by the opening closure 7.
The spring element 8 can comprise a spring or a valve flap of metal, or at least one correspondingly resilient plastics material part. In the embodiment shown, the opening closure 7 comprises a wedge-shaped element which has a face lying obliquely in the gas flow H such that the wedge-shaped element as a result of the gas flow H, counter to the force of the spring element 8, is displaced transversely to the gas flow H. The higher the pressure differential, the more the opening closure 7 is opened, and the larger thus the aerodynamically effective opening area of the wall opening 6.
The separating wall 5 is produced by 3D printing. The separating wall 5 here is printed onto a carrier component 13, for example. In this way, the number of individual parts is reduced and the assembly is facilitated.
Features of the exemplary embodiments illustrated in
While the invention has been explained and described in more detail by preferred exemplary embodiments, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by the person skilled in the art without departing from the scope of protection of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2019 213 344.4 | Sep 2019 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/072589 | 8/12/2020 | WO |
