Induction heater tubes

Recently, my ZVS (the Royer converter) testing jobs  broken when I had used them as induction heater. (Recorded maybe too much power, until she has catapulted is even on the other side.

So we now need replacement.

Since I have now even vacuum tubes there, I wanted to ask if anyone knows a simple wiring diagram (with easy to beschaffbaren components) with which you can build an induction heater, or even better, a multimedia talent, like a zvs.
Because the most tubes use more power than normal FETs, you could pump it so perhaps with more power full.

Oh, Yes: As tubes, I the EF89 and two more of which unfortunately the inscription went off. Hope that it will be enough.

Best would be easy voltage. You're messed up something on that one! These tubes are RF or if amplifier tube, as far as I know from radio receivers. You have a maximum anode current of 9mA what scarce 2,25W'd be at 250V voltage. One fueling anything ;-)
Tubes have generally high anode voltage, but of flows limited on a few types.
With line amplifier tubes (à la PL519) or smaller stock (Pollin transmitting Triodes, GL-15 B (?) or GU50) something could perhaps make, but with such a small tube you come there not far.
Of course there are still overkill variants, E.g. a GU-81M (and that is just the beginning, there is still viiiieeeel more, who want to be paid but also accordingly). When using tubes - then with those that can be 1.5kV.
Thus, you could realize my opinion a normal network ZVS (ugs. Royer converter) on 500 kHz.
Starts from 170kHz, a decent Setup and approximately 1 kW input power provided a glowing 3 mm copper tube in a work coil with almost 3 cm diameter.

With the higher frequency of just the 500 kHz, even items with minimum dimensions can be heated in efficiently.
For massive steel rods and studs, but rather about 50 kHz and IGBTs were attached as the switching element.

Conclusion: The construction of an induction heater tubes is guaranteed possible - with so 25W-Dingern I would forget but very quickly and cleverly inserted the tubes, high frequencies are advisable. At best, the EF89 is good for radio. Performance can not – this is an HF tube for small services. So what in direction PL519 or GU50 would work.
A Royerkonverter should be no problem there, you should realize the circuit without problems with tubes. If there are high voltage cables  still such a page, which is called gidf.de. There are tubes, wiring diagrams for Royerkonverter