Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/668—Means for obtaining or monitoring the vacuum

Definitions

• the invention relates to a method for determining the Internal pressure of an evacuated vessel with at least two mutually insulated electrodes, in particular one High-voltage vacuum interrupter with two contacts.
• the invention also relates to a device for through conduct such a procedure.
• the procedure or the Device are particularly in the production or the Operation of vacuum systems, especially for vacuum switches, but also generally in the field of vacuum measurement technology applicable.
• Vacuum systems usually only work reliably and functionally reliable if a predetermined one, usually lower Internal pressure is guaranteed. This also applies preferably to the functional reliability of the switching chamber of vacuum scarf tern.
• a circuit arrangement for determining pressure is also shown in FIG evacuated vessels, especially in vacuum switches, be knows, when the high voltage is applied from the Cathode emitted field emission current of a noise analysis, e.g. Fourier analysis, where the ratio a measure between high and low frequency noise for the internal chamber pressure is (DD-A-257 296).
• a noise analysis e.g. Fourier analysis, where the ratio a measure between high and low frequency noise for the internal chamber pressure is (DD-A-257 296).
• the vacuum switch is the one emitted by the cathode Field emission current tapped on a condensation screen fen.
• the circuit arrangement consists of at least one Analysis network, a comparator module and a display device.
• the emit from the cathode when the operating voltage is applied and appropriately tapped field emission current is sent to the analysis network that is suitable perform a frequency analysis of the current. It can be out two or more frequency filters, e.g. L-C low frequency filter, exist.
• the signals thus obtained, which the Shares of the noise spectrum in two frequency bands rn pro are proportional, are fed to the comparator module.
• the comparator block e.g. a difference amplifier
• a signal is obtained that corresponds to the ratio of the services in high-frequency and low-frequency Be range corresponds to the current signal noise spectrum and one Display device is fed; with appropriate egg chung, this performance ratio is a direct measure of the pressure.
• the invention is based on the object of a method and a device for determining the internal pressure in evacuated vessels, e.g. B. Vacuum interrupters to indicate, which require relatively little technical effort, whereby the measured value mt is provided outside the vacuum vessel seen means should be recorded.
• evacuated vessels e.g. B. Vacuum interrupters to indicate, which require relatively little technical effort, whereby the measured value mt is provided outside the vacuum vessel seen means should be recorded.
• the inventive method for determining the internal pressure of an evacuated vessel with at least two ge mutually insulated electrodes, in particular a vacuum switching chamber with two switching contacts is characterized by - application of an electrical high voltage (U) to the electrodes acting as anode or cathode, - Detecting the temporal course of the intensity of the emitted electromagnetic radiation outside the vessel, - Determination of the frequency of the temporal change in the intensity of the detected electromagnetic radiation and - Determination of the internal pressure of the vessel on the basis of the previously determined dependence of this frequency on the internal pressure and, if necessary, display and / or registration of the internal pressure.
• U electrical high voltage
• the device according to the invention for determining the internal pressure of evacuated vessels which is particularly suitable for carrying out the method explained above, is characterized by - at least two mutually insulated electrodes - A high voltage source that generates a high electrical voltage (U) that can be applied to the two electrodes acting as anode or cathode, - A probe arranged outside the vessel and directed thereon, which detects the intensity of an electromagnetic radiation emitted by the electrodes, - A processing unit connected downstream of the probe, which determines the frequency of the change over time in the intensity of the electromagnetic radiation detected by the probe and determines the internal pressure on the basis of a predetermined relationship between this frequency and the internal pressure in the vessel, as an output unit that displays and / or records and / or stores the internal pressure and / or outputs it as an analog or digital electrical signal.
• a high voltage source that generates a high electrical voltage (U) that can be applied to the two electrodes acting as anode or cathode
• U high electrical voltage
• a probe arranged outside the vessel
• the probe is in particular connected to the anode or active electrode oriented in the evacuated vessel.
• the device according to the invention is a vacuum high chip is voltage switch, is advantageously the on Vacuum switch in the open state applied high-voltage voltage used as a high voltage source.
• the emitted radiation is in particular an X-ray Radiation, the frequency of which depends on the applied voltage is pending.
• the intensity of this radiation changes constantly with a frequency that is in the range of about 2 up to about 20 Hz.
• This frequency is a measure of the The pressure prevailing in the vessel or test object (vacuum).
• the applied electrical high voltage can be arbitrary Exhibit signal curve or voltage curve; as part of of the invention are particularly DC voltages as well AC voltages applicable.
• the voltage should be about ⁇ 28 kV, with the upper limit ze through the insulation design of the vessel or a vacuum interrupter to be tested.
• Operating voltages of 12 kV or 24 kV correspond to test voltages of 28 kV or 50 kV.
• the Measured variable is an electromagnetic radiation that be can be detected without contact.
• the Solution the newfound knowledge that the time Liche change in the intensity of this detected electro magnetic radiation with a frequency occurs or is superimposed on that in a defined context with the internal pressure in the evacuated vessel.
• the invention The appropriate method thus uses the identified relationship between the internal pressure to be determined and this Fre sequence from.
• the probe for the determination of the electromagnetic table radiation has in particular an ionization chamber mer or another one responsive to X-rays Establishment on.
• the principle of the invention is based on a Embodiment that focuses on a vacuum switch relates, explained in more detail.
• the drawing there is one he inventive device shown with which the Ver driving according to the invention can be carried out.
• a vacuum interrupter chamber 1 In a vacuum interrupter chamber 1 are a condensation screen 2, a movable switch contact 3 and a fixed one Switching contact 4 arranged, the switching contacts 3, 4 do not touch each other, so the switch is open State. To determine the internal pressure in the Vacuum switching chamber 1 is connected to the switching contacts 3, 4 defined voltage is applied, the switching contacts 3, 4 act as an anode or cathode. Because of known physical processes emerge from the vacuum interrupter 1 emits electromagnetic radiation that is beneficial nal contains. This electromagnetic radiation is from a probe 5 for analyzing the useful material contained therein never caught.
• the probe 5 here consists of an ioni sation chamber, in which when voltage is applied the incoming electromagnetic radiation is a particle current is generated, which is used for measured value analysis.
• These Probe 5 is on the vacuum interrupter chamber 1, e.g. at the level of the open switching contacts 3, 4, directed and in a be Correct distance to the surface of the vacuum interrupter chamber 1 arranged.
• the downstream processing unit 6 becomes a useful signal consisting of a flow of photons proportional measuring signal realized.
• the processing unit 6 determines the frequency of the temporal change of the intensity of the probe 5 detected electromagnetic radiation and determined on due to the given relationship between these Frequency and the internal pressure in the vessel 1 is the internal pressure.
• the processing can processing unit 6 detect the measurement signal of the probe 5, the then with a recording device, for example a y-t recorder or a transient memory with a downstream y-t recorder, registered over time and is used for frequency evaluation.
• a recording device for example a y-t recorder or a transient memory with a downstream y-t recorder, registered over time and is used for frequency evaluation.
• the correlation between The frequency and internal pressure can also be due to such ger registrations.
• the output unit 7 is designed so that they the In pressure and / or the change in intensity over time the electromagnetic radiation due to a corre corresponding signal from the processing unit 6 indicates and / or records and / or stores and / or an ent outputs speaking analog or digital signal.
• the determination of the internal pressure of the vacuum interrupter chamber 1 is based on having found that the frequency between anode and cathode when a voltage is applied flowing charge carrier stream is a function of the inside pressure is and the electromagnetic radiation as a carrier of the useful signal through the as a function of time representing charge carrier current is caused.
• the molecules of the vacuum interrupter chamber 1 remaining and predominantly of hydrogen (H2) be standing residual gas adsorb on the surface of the Metal electrodes (3, 4), i.e. the surfaces the switching contacts, whereby a dynamic equation adjusts the weight between adsorption and desorption.
• the time-dependent behavior of the charge carrier flow and thus the electromagnetic radiation is caused by the dynamic process of adsorption and desorption of the Residual gas molecules in the vacuum interrupter (1). It calls a higher internal pressure in the vacuum interrupter chamber with a higher residual gas content a higher adsorption or de sorption rate, i.e. a faster change between Adsorption and desorption, and therefore a higher frequency the change in the intensity of the electromagnetic beam development.
• the device according to the invention for determining the inside pressure of vessels can also be used with other electrode configurations or pots tial assignment than the one previously described can be applied.

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• Measuring Fluid Pressure (AREA)

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Citations (4)

• 1988
  • 1988-10-21 DD DD32096388A patent/DD276358A1/de not_active IP Right Cessation
• 1989
  • 1989-10-19 EP EP19890119418 patent/EP0365005A3/fr not_active Withdrawn

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