DE1046205B - Device for monitoring electron tubes during operation - Google Patents

Description

The operational safety of a device that contains electron tubes is crucially dependent on the behavior of these tubes. It is therefore necessary to monitor the properties of the tubes as continuously as possible in order to determine changes quickly and to avert the risk to the operational safety of the device by replacing faulty tubes. It is known, for this purpose, for each tube to be monitored to measure a variable which is characteristic of the properties of the tube, for example the anode current, at certain time intervals. If the time intervals are not too long, this usually makes it possible to identify and replace aging tubes in good time. To facilitate and accelerate such measurements, known devices contain resistors in the lines that carry the currents to be monitored, at which these currents generate voltage drops. The resistors are expediently dimensioned so that all voltage drops are normally approximately the same. A measuring device placed over each of these resistors in turn reveals the condition of the individual tubes. So that a change in their properties can be seen in good time, it is almost inevitable to graphically display the measured values obtained at certain time intervals for each tube. This is all the more necessary as in many cases tubes of a certain type can carry noticeably different currents in normal operation without this having to be based on a difference in quality. The characteristic of the condition of a tube is therefore not primarily the absolute value of the current to be monitored, but its possible change over time, which must be determined individually for each tube by comparing the latest measurement with previous measurements.

If such measurements are to be carried out at such small time intervals that there is a high probability of avoiding tube failures, then they require a disproportionately large amount of work and time. It is now also known to eliminate this disadvantage and, moreover, to reduce the time intervals to practically any small amount, ie to monitor each tube practically continuously without a complete monitoring device being required for each of them. For this purpose, a relay is used to which the currents to be monitored are fed one after the other by a rotating switch, and which triggers switching processes when certain current values are exceeded or not reached. In practice, the case now often occurs that for the various tubes of a device, depending on the device for monitoring
Electron tubes during operation

Applicant:

"Patelhold" Patentverwertungs- & Elektro-Holding AG _f Glarus (Switzerland)

Representative: Dr.-Ing. E. Sommerfeld, patent attorney,
Munich 23, Dunantstr. 6th

Claimed priority:
Switzerland from April 9, 1956

Mario Delia Spina, Baden (Switzerland),
has been named as the inventor

their task, deviations of the current of very different sizes from the setpoint can be allowed or have to. The present device for monitoring electron tubes allows such Conditions to be taken into account, therefore it has a relay, which the actually to the individual Voltages occurring with the resistors are associated with the voltage divider or in some other way produced and compares target voltages carried out at comparison terminals, a changeover switch connects in cyclical order the relay on the one hand with the individual measuring terminals, on the other hand with the assigned ones Comparison terminals, according to the invention in each position of the switch a resistor in Series connected to the relay, which is dimensioned so that the relay * is at the limits of the tolerance range of the responds to the monitored size.

The drawing shows an embodiment for the device according to the invention. The anode current i _{a of} the electron tube V, which is located in the device G , generates the voltage drop U, which characterizes the anode current, at the resistor R _{1 connected to the cathode circuit.} This voltage drop occurs between the measuring terminal K _L and ground. Further voltages, which are characteristic of further variables in the case of electron tubes (not shown), lie between each of the remaining measuring terminals shown and the ground as a common reference point. The monitoring device W is connected to the device G via the lines L. These lines are via the first switch B ₁ in a cyclical sequence with the one

809 698/394

End of the coil of the relay JT connected. The second changeover switch B ₂ , which runs synchronously with the first changeover switch, connects the other end of the relay coil in a cyclical sequence to the comparison terminals K ₂ . Between each of these comparison terminals and ground there is an adjustable voltage, which is generated by a voltage divider, which consists of the fixed resistor R _z and the variable resistor i? ₄ exists. All voltage dividers are fed from the voltage source U ". Each voltage divider is set so that the comparison voltage U 'is the same as the setpoint value of the associated voltage U. The relay S will therefore remain in the rest position as long as the voltage U is changed; it will respond as soon as this voltage deviates from its nominal value by a certain amount, be it up or down. A resistor R ₂ is now provided for each position of the changeover switch, which is connected in series with the relay and which allows If, for example, an alarm is to be triggered when the current has decreased by a relatively small amount in a certain tube, then it is sufficient to select the resistance R _{2 to be relatively small} small difference between the voltages U and XJ ' a relatively large current in the relay coil, so that the relay 6 "responds to a current change of, for example, a few percent.

The two changeover switches B ₁ and B ₂ are continuously moved on by any device M known per se. The changeover switches can consist, for example, of step switches known in telephony technology, the device M then being such that it periodically supplies current pulses for switching the step switches. Any alarm direction can be connected to the terminals K _{3 of} the relay 5 ″, which then indicates those changes in the properties of the monitored tubes which exceed the permissible tolerance S the continuation of the changeover switches B ₁ , B _{2 is} prevented, and the position of this changeover switch can be used to infer the defective tube immediately.
A so-called contact micro-ammeter, which has a rotating system similar to that of an electrical measuring instrument, is advantageously used as the relay. The pointer, whose rest position is in the center of the scale, touches depending on the

ίο Direction of current one of two contacts. Such Relays are characterized by their high sensitivity and therefore make it possible without disturbing the tube functions also monitor small currents (e.g. in detector circuits).

Oie. Design of the present device enables an effective monitoring of devices that contain electron tubes, because the device always responds when the changes in the tube data reach a tolerance limit,

ao how different the tolerances in the individual Tubes may be.

Claims (1)

PATENT CLAIM: Device for monitoring electron tubes, in which means are available for each variable to be monitored at a measuring terminal is compared to a voltage that characterizes this variable generate a common reference point, and which contains a relay that is triggered by a Changeover switch in cyclical sequence on the one hand to the individual measuring terminals and on the other hand to assigned Comparison terminals are placed at which the individual Target voltages are maintained, characterized in that in each position of the Changeover switch a resistor is connected in series to the relay, which is dimensioned so that the relay responds to the limits of the tolerance range of the respective monitored variable. Considered publications:
German patent specification No. 873 431. 1 sheet of drawings