초록 ▼

Poorly conducting substances, such as chips of cellulose material containing a heat hardenable binder, are heated by passing them between the plates of an operational capacitor supplied with energy from a high frequency generator. An adjustable auxiliary capacitor is connected in parallel with the o

Poorly conducting substances, such as chips of cellulose material containing a heat hardenable binder, are heated by passing them between the plates of an operational capacitor supplied with energy from a high frequency generator. An adjustable auxiliary capacitor is connected in parallel with the operational capacitor and is adjusted to match the capacity of the output circuit to the generator with changing conditions of the poorly conducting substances. Coarse initial control is effected by adjusting the separation of the plates of the operational capacitor. The apparatus is especially useful for making chip boards and the like in which a precompressed mass of chips is passed between the plates of the operational capacitor sandwiched between two endless belts.

대표청구항 ▼

A method of heating a continuously moving mass of relatively poorly electrically conducting material of variable electrical characteristics and height by dissipating relatively high frequency electrical energy from a generator in a load circuit including an operational capacitor and an auxiliary cap

A method of heating a continuously moving mass of relatively poorly electrically conducting material of variable electrical characteristics and height by dissipating relatively high frequency electrical energy from a generator in a load circuit including an operational capacitor and an auxiliary capacitor connected together to the high frequency generator the method comprising, the steps of: (a) continuously moving the mass of material through a space between the electrodes of the operational capacitor; (b) continuously monitoring a parameter of the high frequency generator related to the power output from the generator to the load circuit; adjusting the capacity of the load circuit to adjust the value of said parameter to a value corresponding to a predetermined power dissipation in the moving mass of material; (c1) said adjusting step (c) including: adjusting the auxiliary capacitor in response to deviations of the monitored parameter from its desired value to change the capacity of the load circuit whereby to effect a fine compensation for changes in the load circuit brought about by variations in the electrical characteristics and height of said moving mass of material and to restore said parameter to its predetermined value; (c2) sensing when the auxiliary capacitor has reached the limits of its range of adjustment; and (c3) as necessary making a relatively coarse adjustment of the capacitance of the operational capacitor to restore the parameter to its desired value and to reset the auxiliary capacitor to within its range of adjustment.