Willet PARRY
ElectroCulture
US Patent # 2,308,204
Means for Affecting Plant
Life Processes
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%
germinative. 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
heretofore available.
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:
Figure 1 is a circuit
diagram, partially fragmentarily elevational, of the apparatus;
Figure 2 is a fragmentary
plan;
Figure 3 is a voltage stress
diagram.
The materials m to be
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 24.
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 required.
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 and 6.
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
stock m transversely to
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 respectively.
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...
