e2v gridded tubes are available in power ranges up to 540 kW and operating through the RF spectrum up to 120 MHz. They are used in a variety of applications including induction and dielectric heating.
The outstanding performance and long service life of our industrial tubes combine to provide lower cost of ownership. With direct equivalents for many competitor devices, low-cost conversions available where no direct equivalent exists and over 50 years experience in this field, we are able to provide exceptional levels of customer service and support. In addition, our technical teams develop new products in partnership with our clients to ensure a perfect fit with evolving OEM product ranges and we strive to offer continuous improvement in manufacturing lead times.
Induction heating is a method of heating conductive material by subjecting it to an alternating electromagnetic field, usually at frequencies between 100 and 500 kHz.
An inductor (the work coil), acting as a primary winding of a transformer, surrounds the material which is to be heated (the work piece), which acts as the secondary winding. Alternating (RF) current flowing in the primary coil induces eddy currents in the work piece and heats it up. The frequency of the primary alternating current, along with the permeability and resistivity of the material, decide the depth that the eddy currents penetrate and therefore the distribution of heat within the work piece. The particular design of the coils, along with temperature sensors and feedback controls, allows either the entire work piece or a specific area to be heated. The repeatability of the process is excellent.
Oscillator circuits containing triodes are commonly used to generate the RF currents.
Typically induction heating is used in pipe welding and induction hardening/heat treatment.
Dielectric heating (also known as Capacitance heating) is the method of heating non-conductive materials. The material to be heated is placed between two electrodes, to which a high-frequency energy source is connected. The oscillating field passes through the material and as the field direction changes, the polarisation of individual molecules reverses rapidly, causing friction and hence heat. The higher the frequency, the greater the movement. Typically, frequencies in the range 5 MHz to 80 MHz are used. This technology is used in Wood Gluing, RF Drying and Plastic Welding
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