US Patent # 2,308,204
Means for Affecting Plant
This invention relates to a method of and apparatus for activation
or suppression of biological processes, especialy those processes
substantially affected by high frequency electric fields.
This method provides for practical treatment of substantial
quantitites of stock by industrial concerns so efficiently that
the benefits of such treatment are available to effect substantial
industrial economy. For example, it is advantageous to treat seed bean stock having an untreated
germination factor of from 2 to 4 % and render that stock 40%
. In like manner the method is effective in
the activation or deactivation of fruits to accelerate or retard
their life processes, and to delay the advance of their
maturation, as well as to otherwise control plant life through
promotion of plant health as by devitalization of parasitic,
fungus, and insect pests.
Industrial application of high frequency treatment requires the
expensiture of large amounts of energy and equipment capacity not
In accordance with the principles of my invention the materials to
be treated are subjected to variable high voltage and high
frequency electric fields, being passed therethrough for a period
of time dependent upon empirical determination of effectiveness.
The requisite energy capacity for industrial application is made
available between two electrodes, or electrically conductive
plates, the dimensions of which are so calculated with respect to
the frequency of the electric field required that these two
electrodes have resonant characteristics, that is to say, a
maximum proportion of available energy is available for activation
of the material between the plates.
The frequency of the energy pulses supplied to the plates is
preferably maintained by an electric oscillating circuit, an
oscillator being so related to the electrodes that the voltage of
the energy passing to the electrodes is varied in accordance with
the oscillator energy wave, in such fashion that it is impractical
to permit its flow in ordinary oscillating circuits such as
heretofore been employed.
In the drawing:
is a circuit
diagram, partially fragmentarily elevational, of the apparatus;
is a fragmentary
is a voltage
The materials m
treated are carried by an endless belt 2, one each of which passes
through an electric field produced by an oscillating voltage
difference existing between a pair of conducting plates 4 and 6 to
the adjacent ends 8 and 10 of each of which are attached a figh
frequency electric energy supply, here comprising the plates P of
power vacuum tubes 12 and 14. The filaments of these tubes are
attached to the negative terminals of a power supply 16, the
positive bus 13 of which supply is electrically conected to the
remote ends 20 and 22 of plates 4 and 6 as by a slide contractor
The distance between the points A and B in meters is calculated as
300,000,000 divided by 4 times the frequency in cycles per second,
or one-quarter wave length of the frequency to be used.
Accordingly, if the frequency required for a particular processing
is 15 MHz, the distance AB is 5 meters. As the frequency
increases, AB becomes shorter and the slider 24 may be adjusted
for this requirement, or plates of different lengths may be
provided, integrated therewith at 20 and 22, for each frequency
The energy passing to the plates 4 and 6 is controlled by the
oscillator circuit grids G which form the termini of the variable
oscillator circuit O, and which receives its energy from the
direct current source 16-18.
A variable capacitor VC adjusts the oscillator frequency and
voltage thereof is applied on the grids G, which, in turn,
influence the flow of current from the filaments F to the plates 4
and 6 so that the natural or resonant frequency of the oscillator
circuit is exactly equal to the resonant frequency of the lines 4
If a larger capacity is desired the widths of the plates 4 and 6
may be increased and the speed of travel of the belt 2 may be
enlarged in accordance with the demand for additional capacity.
As illustrated, the field is created by a resonant line, short
circuited at its remote end. Other resonant lines and oscillating
circuits may be employed, with a generally like effect, but that
described is preferable.
As illustrated, employing the paltes 4 and 6 alone, and moving the
the length AB, it is evident that the voltage stress varies from A
to B, being at all times a maximum at A and zero at B, and
distributed according to the nature of the imposed sine wave from
A to B. Accordingly, diverse portions of the material along the
belt from A to B are subjected to different voltage gradients and
this fact must be taken into account. If voltages between the
limits are satisfactory, the position of the material on the belt
may be specified for this exigency.
If uniform treatment is desired, the material may be moved in the
direction AB or BA, so that all of it passes through the same
section across the line AB.
Treatment between certain voltage limits is often satisfactory and
in such instances the arrangement employing an additional set of
plates 4'-6' which are shorted at B' and have input terminals at
A', in opposed relation to AB, is useful. The material at the
midpoint is subjected to the least stress, which would be the
maximum available for any constant condition, while the maximum
voltage would be available between the ends of the plate pairs
Instead of using the belt 2, the plates 4 and 6 may be juxtaposed
in vertical planes, as imaginable in connection with Figure 2, and
so proportioned with respect to velocity of free fall, or
restrained fall, of material in process therebetween, that the
required length of treatment is obtained.
It has been pointed out that large quantities of energy may be
usefully expended incident to the resonant condition between
plates 4 and 6 without, however, dissipating excessive quantities
of waste energy due to resistance and electromagnetic losses. This
is made possible by the resonant characteristics of the plates,
their large size in respect of the material to be treated, and
their size in comparison with the wavelength...