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Patent No. 6263878 Means for protecting living systems from adverse effects of electric, magnetic and electromagnetic fields (Litovitz, Jul 24, 2001)
Assignee: The Catholic University of America (Washington, DC)
Abstract
An arrangement for inhibiting the adverse effect of an ambient time varying field having an electric component of 5 Kv/M or less and/or a magnetic component of 500 .mu.T or less on a living system. To provide protection, at least one of the characteristic parameters of said field to which the living system is exposed is changed within time intervals of less than 10 seconds.
Notes:
BACKGROUND
OF THE INVENTION
1. Field of the Invention
This invention relates to methods and apparatus for protecting living systems
from adverse effects upon them of electric fields, magnetic fields and electromagnetic
fields.
2. Background and Discussion of Related Art
For some years past there has been a growing recognition and concern that humans
are suffering adverse effects, notably cancers, from living and/or working in
ambient electromagnetic fields, particularly those fields which are alternating
or pulsating or being modulated at frequencies below 500 Hz. Ambient frequencies
particularly identified with an enhanced risk of cancer are those "power" frequencies
at 60 Hz (U.S.) and 50 Hz (U.K. and continental countries). Electromagnetic
fields existing near devices using cathode ray tubes also are implicated, due
to fields generated by the magnetic electron beam deflecting devices included
in the tube control apparatus.
Various articles have been published on the electromagnetic field problem. Over
the past 11 years a series of epidemiological studies have found that low level
electromagnetic fields [even as low as 1 .mu.T (1 micro Tesla) for 60 Hz power
line fields] can be correlated with increased incidence of certain diseases.
This correlation is strongest for those who have lived or worked in this environment
for many years. For example, an increased risk of cancer has been found among
children who lived for several years close to power lines (Wertheimer, N. and
Leeper, E. "Electrical Wiring Configurations and Childhood Cancer", AM. J. EPIDEMIOLOGY,
109. 273-284 (1979); also, Savitz, D. A. et al., "Case Control Study of Childhood
Cancer and Exposure to 60-Hertz Magnetic Fields," AM. J. EPIDEMIOLOGY, 128,
10-20 (1988); also, Milham, S. Jr., "Increased Mortality in Amateur Radio Operators
Due to Lymphatic and Hematopoietic Malignancies," AM. J. EPIDEMIOLOGY, 128,
1175-1176 (1988). The research indicates that children from high electromagnetic
field exposure homes have a 50 percent greater risk of developing cancer, particularly
leukemia, lymphomas, and nervous system tumors. Other data also show that men
working in electrical jobs, such as electricians and telephone lineman are at
higher risk for brain tumors and other cancers. In a recent study in the Los
Angeles area, S. Preston-Martin and collaborators at the University of Southern
California found that men who had worked for 10 years or more in a variety of
electrical occupations had a ten times greater chance of getting brain tumors
than men in the control group. [Preston-Martin, S., and Mack, W. and Peters,
Jr. "Astrocytoma Risk Related to Job Exposure to Electric and Magnetic Fields,"
presented at DOE contractors Annual Review, Denver Colo., Nov. 5-8, 1990.] A
study performed by G. Matanoski of Johns Hopkins University found a dose response
relationship for cancers in male New York Telephone employees from 1976 to 1980.
[Matanoski, G., Elliot, E. and Breysse, P. Poster presented at the annual DOE/EPRI
Contractors Review of Biological Effects from Electric and Magnetic Fields,
November 1989, Portland, Oreg.] Matanoski measured the average magnetic field
exposure among different types of employees and then installation and repair
workers. A comparison of the cancer rates among the various types of employees
showed that cable splicers were nearly twice as likely to develop cancer as
those employees who did not work on telephone lines. Among central office workers
those who were exposed to the short intense fields of telephone switching equipment
the rates of occurrence of cancers were unusually high, although not as high
as for cable splicers. The central office workers were more than three times
as likely to get prostate cancer and more than twice as likely to get oral cancer
as co-workers who were less exposed. And there were two cases of male breast
cancer, a disease so rare that no cases at all would be expected.
The 60 Hz electromagnetic fields found in residential settings can vary from
about 0.05 .mu.T to over 1000 .mu.T. In-vitro experiments have definitely shown
that changes in biological cell function can occur in fields as low or lower
than 1 .mu.T and as high as 500 .mu.T. R. Goodman and collaborators [Goodman,
R. and Henderson, A., "Sine Waves Enhance Cellular Transcription,"BIOELECTROMAGNETICS,
7, 23-29, 1986)] have shown that RNA levels can be increased by electromagnetic
fields ranging in frequency from 15 to 4400 Hz with amplitudes of 18 to 1150
.mu.T. They have shown that the RNA levels can be enhanced by factors of ten
or more. Jutilainen and coworkers [Jutilainen, J., Laara, E. and Saali, K.,
INT. J. RADIAT. BIOL.,52, 787-793, (1987)] have shown that 1 .mu.T 50-Hertz
electromagnetic fields can induce abnormalities in chick embryos. Thus, electromagnetic
fields appear not only to be carcinogenic, but also capable of inducing birth
defects. Pollack and collaborators, C. T. Brighton, E. O'Keefe, S. R. Pollack
and C. C. Clark, J. ORTH. RES. (to be published), have shown that electric fields
as low as 0.1 mv/cm at 60 kHz can stimulate growth of bone osteoblasts. McLeod
and collaborators have found that in the region between 1 Hz and 100 Hz, much
lower fields are needed to stimulate fibroblast growth than at frequencies above
and below this range [McLeod, K. J., Lee, R. and Ehrlich, H., "Frequency Dependence
of Electric Field Modulation of Fibroblast Protein Synthesis," SCIENCE, 250,
1465 (1987)].
Reported related research on animals is not as extensive as for humans, but
there is every reason to believe that the same adverse effects occur in them
as in humans. Therefore, protection of living systems including but not limited
to humans and animals are encompassed within the present invention.
SUMMARY OF THE INVENTION
I have concluded that the aforesaid adverse health effects upon living systems
(including but not limited to single cells, tissues, animals and humans) may
be inhibited by changing in time one or more of the characteristic parameters
of the ambient time varying electric, magnetic or electromagnetic field to which
the living system is exposed. This may be done in a number of ways, for example,
by changes in one or more of frequency (period), amplitude, phase, direction
in space and waveform of the field to which the living system is exposed. As
for the time periods between changes, I have concluded that these time periods
should be less than approximately ten (10) seconds, and preferably should not
exceed approximately one (1) second. The changes may occur at regular or irregular
intervals. These changes can be accomplished by superimposing these special
time-dependent fields upon the ambient field, or by changing with time the characteristic
parameters of the original fields.
The change or changes in the ambient field should be about 10 percent or more
of the related characteristic parameters of the field before the change.
My proposal to protect living systems from the adverse effects of electric,
magnetic or electromagnetic fields by creating special ambient fields as aforesaid
is based on my conclusion that something must be done to confuse the biologic
cell so that it can no longer respond to the usual fields found in the home
and work place. I have discovered that the fluctuating fields mentioned above
will prevent the adverse effects of the usual environmental fields. As above
stated, these fluctuations can occur either in the amplitude, frequency (period),
phase, wave form or direction-in-space of the newly created "confusion" field.
To affect cell function some insult (e.g. drug, chemical, virus, electromagnetic
field, etc.) will cause a signal to be sent from receptors (often at the cell
membrane) into the biochemical pathways of the cell. Although the exact receptor
and signaling mechanism utilized by the cell to recognize the fields is not
known, I have discovered that this mechanism can be stopped by confusing the
cell with fields that vary in time in the ways specified herein.
For example, a 60 Hz electromagnetic field having a magnetic component of 10
.mu.T can cause a two fold enhancement of the enzyme ornithine decarboxylase.
If this field is abruptly changed in frequency, amplitude, wave form, direction
or phase at intervals of more than 10 seconds, the two fold enhancement persists.
If, however, the frequency, amplitude or waveform parameters are changed at
approximately 1 second intervals, the electromagnetic field has no effect. The
cell does not respond because it has become confused. Similar electric fields
in tissue with amplitudes ranging from 0.1 to 50 .mu.v/cm. can be useful in
protecting the living system from adverse effects. To create these fields at
60 Hz. the field strength outside the living systems must be about one million
times larger (i.e. 0.1 to 50 v/cm.)
I consider that my invention functions with ambient fields having an electric
component of 5 Kv/M or less and/or a magnetic component of 500 .mu.T or less.
As for lesser field strengths, electric components of 0.5 Kv/M and/or magnetic
components of 50 .mu.T are exemplary.
For best results the confusion field should contain frequency components similar
to that contained in the ambient fields. The vector component of the "confusion"
field along the direction of the ambient field should be approximately the same
as the value of the ambient field. The time between changes in properties such
as frequency, phase, direction, waveform or amplitude should be less than 5
seconds for partial prevention of adverse effects but preferably less than 1
second for much more complete protection.
It is preferred to have the field to which the living system is exposed be my
confusion field for the duration of the exposure. However, benefit will be achieved
if my confusion field is in existence for only a major portion of the total
exposure time.
I have referred above to electric, magnetic and electromagnetic fields because,
insofar as they are distinct, ambient fields of each type are capable of causing
harm to living systems, but if changed according to my invention will inhibit
the on-set of adverse effects. For convenience in the remainder of this specification
and in the claims, I use the term electromagnetic field as a generic description
embracing the three types of fields.
DISCUSSION OF BACKGROUND OF THE INVENTION
To the best of my knowledge, to date no one has heretofore proposed my invention,
although over ten years have elapsed since the first recognition of the dangers
of chronic electromagnetic field exposures to humans.
There have been many teachings about the use of electromagnetic fields to treat
humans for pre-existing diseases or conditions. For example, U.S. Pat. No. 4,066,065
(Kraus 1978) describes a coil structure to create a magnetic field for treatment
of a hip joint. U.S. Pat. No. 4,105,017 (Ryaby 1978) describes a surgically
non-invasive method of and apparatus for altering the growth, repair or maintenance
behavior of living tissues by inducing voltages and concomitant current pulses.
U.K. Patent GB 2 188 238 A (Nenov et al. 1986) describes an apparatus alleged
to provide analgesic, trophic and anti-inflammatory effects. Costa (1987) U.S.
Pat. 4,665,898 describes a magnetic coil apparatus for treatment of malignant
cells with little damage to normal tissue. An apparatus for treatment of diseases
of the peripheral and autonomic nervous system as well as other diseases has
been described by Solovleva et al. ("Polyus-1' Apparatus for Low-Frequency Magnetotherapy,"
G. Soloreva, V. Eremin and R. Gorzon, BIOMEDICAL ENGINEERING (Trans. of: Med.
Tekh, (USSR)), Vol. 7, No. 5, pp. 291-4 (1973).
The above procedures are usually referred to as "magnetotherapeutic" procedures.
My invention focuses instead on the prevention of disease caused by long term
exposure to ambient time varying electromagnetic fields. To date, no other proposals
have been presented which utilize modifications of the time dependence of the
ambient fields to prevent adverse health effects of ambient electromagnetic
fields. Basic to all the patents and articles which describe the treatment of
pre-existing diseases by electromagnetic fields (magnetic therapy) is the assumption
that electric or magnetic fields (often of large magnitude, e.g. 1 to 100 T
Ryaby 1978), if applied for some limited period of time, can beneficially alter
the functioning of the cells and tissues within living systems. Now that it
is known that chronic, long term exposure to even very low level, time varying
electromagnetic fields (e.g., magnetic fields as low as 0.5 .mu.T) can cause
some of the very diseases which short term therapeutic doses of these fields
are used to treat. Methods of protection from the biological effects of magnetic
fields have been sorely needed. To find this protection it was necessary for
me to recognize that magnetic therapy is carried out by affecting biologic cell
function. It had to be realized that if magnetic therapy does not affect the
physiological functioning of the living system then no therapeutic effect could
result. What was needed, which the present invention provides, is a method of
modifying the ambient fields in which living systems exist in such a way that
they have no effect on cell function. This modified field has no utility in
the treatment of any disease or biologic malfunction. This modified field is
not of any use in magnetic therapy. However, this modified field (because it
does not affect the function of the cells and tissues of the living system)
has no adverse health effects. Thus, long term exposure to these modified fields
will be safe. These modified fields would not, for example, increase the risk
of developing cancer.
However, none of the above authors, or anyone else before me, had discovered
that periodically changing these very low ambient fields as described elsewhere
herein can prevent harmful effects of electromagnetic fields.
OBSERVATIONS IN SUPPORT OF THE INVENTION
I have been able to support the operability of my invention by several observations
and procedures. One observation has been the effect of coherence time (defined
herein as the time interval between changes of the characteristic parameters
of the fields) of the applied field on bioelectromagnetic enhancement of ornithine
decarboxylase (ODC) specific activity.
Specific activities of this highly inducible enzyme were examined following
mammalian cell culture exposure to electromagnetic fields. Monolayer cultures
of logarithmically growing L929 cells were exposed to fields alternating between
55 and 65 Hz. The magnetic field strength was 1 .mu.T peak. The cells were exposed
to the fields for four hours. The time intervals between frequency shifts varied
from 1 to 50 seconds. See Table 1.
TABLE 1 Role of Time Intervals Between Frequency Changes on the Effectiveness
of Electromagnetic Exposure in Modifying ODC Activity Ratio of ODC Activity
in Exposed Compared to Unexposed Cells Time interval between frequency changes
(seconds) 0.1 1 5 10 50 (1) ELF (55 -- 1 1.4 1.9 2.3 to 65 Hz) (2) Microwaves
1 1 1.5 2.1 2.1 (modulated alternately by 65 and 55 Hz)
It can be seen from Table 1, (1), that when the time intervals between frequency
shifts in the electromagnetic fields were 10 seconds or greater, the electromagnetic
field exposure resulted in a two-fold increase in ODC activity. When the time
intervals between frequency shifts (i.e. between 55 Hz and 65 Hz) were shortened
to less than 10 seconds, the effectiveness of these ELF (extremely low frequency)
fields in increasing ODC activity diminished. At 1 second and below the fields
had no effect at all (i.e., the activity of the exposed mammalian cells was
the same as for unexposed cells). Thus we see that introducing changes in parameters
of the electromagnetic field at short enough time intervals prevents any action
of the field on cell function.
This finding applies to electromagnetic frequencies as high as the microwave
region. Similar data were obtained using 0.9 GHz microwaves modulated at frequencies
changing between 55 and 65 Hz at intervals of time ranging from 0.1 to 50 seconds.
A 60 percent amplitude modulation was used and the specific absorption rate
was 3 mW/g. As can be seen in Table 1, (2), when the time interval was 10 seconds
or greater, this microwave field also caused a two-fold increase in ODC activity.
At shorter time intervals the effect of the field on ODC activity diminished.
When the time intervals between changes were one second or less, the field had
no effect on ODC activity.
To further demonstrate the protective effect of my confusion fields, I studied
the effects of modulation on the ability of exogenous electromagnetic fields
to act as a teratogen and cause abnormalities in chick embryos. In experimental
methods now described, I modulated the amplitude of a 60 Hz electromagnetic
field. Fertilized White Leghorn eggs were obtained from Truslow Farms of Chestertown,
Md. These were placed between a set of Helmholtz coils inside an incubator kept
at 37.5.degree. C. During the first 48 hours of incubation one group of eggs
was exposed to a 60 Hz continuous wave (cw) sinusoidal electromagnetic field
whose amplitude was 1 .mu.T. Another group was exposed to a 60 Hz cw sinusoidal
electromagnetic field whose amplitude was 4 .mu.T. Another group of eggs was
exposed to a 60 Hz sinusoidal electromagnetic field whose amplitude was varied
from 1.5 to 2.5 .mu.T at 1 second intervals. Control eggs were simply placed
in the incubator and not exposed to an electromagnetic field. After 48 hours
of incubation the embryos were removed from their shells and examined histologically.
It was found that the control group (not exposed to the 60 Hz magnetic field)
exhibited about 8 percent abnormalities. The embryo groups exposed to 1 .mu.T
and 4 .mu.T fields had a higher abnormality rate (14 percent) than the controls
indicating that these fields had indeed induced abnormalities. Those embryos
exposed to the fields modulated at 1 second intervals had an abnormality rate
the same as the unexposed eggs. Thus the 1 second modulation (or coherence time)
effectively eliminated the teratogenic effect of the magnetic field.
BRIEF DESCRIPTION OF THE DRAWINGS
I will next describe various techniques and apparatus for carrying out my invention.
These descriptions will be aided by reference to the accompanying drawings,
in which:
FIG. 1 is a plot of amplitude vs. time of a sinusoidal function modulated as
to amplitude.
FIG. 2 is a plot of amplitude vs. time of a sinusoidal function modulated as
to frequency.
FIG. 3 is a diagram of a circuit for modulating electric current through a plumbing
pipe.
FIG. 4 is a diagram of a protective circuit for an electric blanket.
FIG. 5 is a diagram of a protective apparatus for use with a video display terminal.
FIG. 6 is a diagram of another form of protective circuit for use with a video
display terminal.
FIG. 7 is a diagram of a protective system for use in a space occupied by humans.
FIG. 8 is a diagram of a mat for placement on or under a mattress used for sleeping
purposes.
DETAILED DESCRIPTION OF PRESENTLY PREFERRED
EMBODIMENTS
There are many different methods and related apparatus of converting a harmful
field into a "confusion" field. Some of these are as follows:
1. Place several time dependent grounding devices on the metal plumbing pipes.
These devices cause fluctuating paths for electric current in the plumbing pipe
and therefore fluctuating fields in any room in the house or other human or
animal-occupied structure.
2. Insert fluctuating resistance paths in series with heating devices such as
electric blankets.
3. Place devices near appliances and computers which create fluctuating electromagnetic
fields near the computers or appliances. These fields are superimposed on the
uncontrolled source of the original harmful field.
4. Eliminate hazards created by the electromagnetic fields in the region around
electric devices, by modulating the electric current flowing in the device.
The modulation can be caused by means which are external or internal to the
device.
5. Eliminate hazards created by the electromagnetic fields in the region around
electric devices, by modulating the voltage in the device. This modulation can
be caused by means which are external or internal to the device.
6. Eliminate hazards created by the electromagnetic fields in the region around
electric devices, by modulating the electromagnetic field around the device.
This modulation can be caused by means which are external or internal to the
device.
7. Eliminate hazards created by the electromagnetic fields in the region around
electric heaters, such as electric blankets, heating pads, and electrically
heated water beds, by modulating the current and/or voltage in the device. This
modulation can be caused by means which are external or internal to the device.
8. Eliminate hazards created by the electromagnetic fields in the region around
electric power distribution systems by superimposing a modulated electromagnetic
field in the region of space to be protected.
9. Eliminate hazards created by the electromagnetic fields in the region around
the metallic plumbing used to ground electrical lines by superimposing a modulated
electromagnetic field in the region of space to be protected. This can be done
by passing modulated currents through the plumbing itself or by passing modulated
currents through external circuits.
10. Eliminate hazards created by the electromagnetic fields around cathode ray
tube devices such as video display terminals and television sets by superimposing
a modulated electromagnetic field. The source of this electromagnetic field
can be placed either inside or external to the device.
11. Eliminate hazards created by the electromagnetic fields in the region around
microwave ovens by superimposing a modulated electromagnetic field in the region
of space to be protected.
12. Clearly many of the above procedures may be adapted to protect laboratories,
industrial plants, etc., wherein cells not in humans or in multi-cell living
systems may exist.
SPECIFIC PROTECTIVE ARRANGEMENTS
Any voltage, current, electric field, magnetic field, or electromagnetic field
which varies repetitively in time can be described by its waveform, peak amplitude
(A), frequency (period), direction and phase. Modulation of the wave refers
to the time dependent variation of any of these parameters. For example, pulse
modulation of the amplitude of any of the parameters refers to a change in amplitude.
Two examples of this modulation are shown in FIGS. 1 and 2. In FIG. 1 the amplitude
is modulated by a pulse. Thus, for a period of time, T.sub.1 the amplitude of
the sinusoidally varying voltage is A,. For a second time period, T.sub.2, the
amplitude is A.sub.2. The values of T.sub.1 T.sub.2 need not be equal but they
must each be about second or less for best results. Many variations in the modulation
of a time varying voltage can be used, such as a sinusoidal modulation of the
original sine wave. Thus, a 60 Hz sine voltage could be amplitude modulated
by a 1 Hz sinusoidal variation. Another possibility is a saw tooth variation
in the amplitude of a 60 Hz sine voltage. In all of the possible modulated fields,
at least one of the parameters, such as amplitude, waveform, phase, direction
or frequency must not be constant for a time duration of more than about 1 second.
Thus, for example, in FIGS. 1 and 2 the values of T.sub.1 and T.sub.2 must not
be longer than about 1 second. For best results, A.sub.1 should be greater than
1.2A.sub.2, and preferably greater than 2A.sub.2. Similarly w.sub.1 (omega.sub.1)
should be at least 20 percent larger than w.sub.2 and preferably 50 percent
larger than w.sub.2.
Whenever a microwave field is being modulated at a frequency of 100,000 Hz or
less, steps should be taken to achieve protection under my present invention
by periodic parameter changing as described herein.
Protection from copper plumbing may readily be achieved. With reference to FIG.
3, devices 10 are switches either electronically or mechanically controlled
which switch on and off at intervals of one second (e.g. one second on and one
second off). During the "on" intervals this will cause some of the current flowing
past point A and B in the copper pipe 12 to alternately flow through ground
rather than entirely through the pipe. Thus, the current flow from A to B (which
creates an electromagnetic field in the working and living spaces of the structure)
will be modulated (by reduction in current) at intervals of no greater than
one second. The number of devices needed will depend on the complexity of the
piping.
Protection from electric blankets is readily achieved. In FIG. 4 device 14 (the
protective circuit) is a switch which turns the electric current through the
blanket 16 on and off at intervals of one second. The device 14 need not switch
the current completely off. It could, for example, reduce the current by 50
percent, and then within one second return the current to its full value. The
device 18 is the usual thermostat supplied with electric blankets. Neither the
"on" nor the "off" interval should be greater than 3 seconds, and preferably
one second.
Harmful effects of video display terminals may be avoided. In FIG. 5 the video
display terminal 20 is protected by a source 22 of electromagnetic field. B.sub.VDT
and B.sub.PD are, respectively, the magnetic fields of the video display terminal
(VDT) and the protective device (PD). The average amplitude of B.sub.PD at any
point in the region to be protected should be greater than 50 percent of the
amplitude of the field due to the VDT. Preferably, the average amplitude B.sub.PD
should be at least twice the amplitude of B.sub.VDT. If the protective field
of PD is in the same direction as the VDT field it will be most effective. If
the PD field is perpendicular to the VDT field, it must be five times larger
than the VDT field.
FIG. 6 is a system like that in FIG. 5 except here the PD 24 is a coil mounted
around the VTD 20.
The protective device can be any device which generates a time varying modulated
electromagnetic field.
For example, if a coil with ten turns of wire is to be used, it can be mounted
either as in FIG. 1, or in
FIG. 2. In FIG. 1 the coil is placed on a surface near the VDT and oriented
so that its field intersects the field of the VDT. In FIG. 2 the coil is placed
around the outer edge of the front of the VDT. In a typical VDT the coil could
be a square about 40 cm on each side. The average current in the coil should
be adjusted so that the average field at the front and center of the monitor
due to the coil is preferably about equal to that field at the same point due
to the VDT. For example, if the average field at the very front of the monitor
is 10 .mu.T a 10 turn coil of wire 40 cm on edge could have a 60 Hz cw current
of approximately 0.35 amps flowing through it. The current could be alternatively
0.5 amps for 1 second and then 0.2 amps for 1 second.
It will be understood that a standard TV set (one case of VDT) can be protected
in the same manner as VDTs or "computers". Oscilloscopes may similarly be protected.
Large areas may also be protected. Referring to FIG. 7, 26 and 28 are large
coils of wire (e.g. 7 ft high by 7 ft wide) mounted on or near opposite walls
of a room, or on the floor and ceiling. The latter configuration is more effective
than the former when the ambient fields are in a vertical direction. It is assumed
that the room is exposed to a cw electromagnetic field that is dangerous to
living systems. Modulated current (e.g., "on" and "off" at one second intervals)
flows through the coils. The current and the modulation in coil 26 is kept in
phase with the current and modulation in coil 28. The pair of coils act as Helmoholtz
coils and tend to keep the field in the protected region more uniform than if
a single coil were used. The average amplitude of the current in the coils should
be such that the electromagnetic field produced by the coils at every point
in the region to be protected is at least 50 percent of the erstwhile ambient
field and preferably 5 to 10 times the ambient value.
A single coil can be used instead of the a pair of coils. The larger the coil
the better; a larger coil will provide a more uniform protected region than
a small one.
Special mats containing coils can be used in the home, laboratory, or other
living system inhabited place to provide general protection. For example, a
large percentage of the time spent at home is by a human sleeping on a bed.
Thus, it would be useful for those who live near power distribution lines to
use a device which puts the human in a protective "confusion" field during the
time during which he is lying on the bed. As shown in FIG. 8, this can be done
by imbedding a many turn coil of wire 30 in a mat 32 and placing this mat either
on or under the mattress 34, but near the head of the bed for maximum protection
of the vital organs. The wire should be of low resistance, since it would be
used year round and should not have significant heating of the bed or its occupants.
This coil of wire would have the modulated current flowing through it during
all seasons. The modulated electromagnetic field would protect the occupants
of the bed from the ambient electromagnetic fields in the room. For example
for a queen size bed a square coil of wire with 10 turns approximately 60 inches
by 60 inches square and with 0.14 amperes of current flowing will yield at the
center of the coil a magnetic field in the vertical direction of about 1 micro
Tesla. If the bed is over 100 feet away from a power line 20 feet in the air,
the ambient magnetic field due to the power line is also in the vertical direction.
Thus, we have an optimum alignment of the field of the coil and that of the
power line. To create a confusion field the current in the coil should vary
from about 0.03 amperes to 0.07 amperes and back at least once every second
yielding a coil field at the center which fluctuates between 0.5 and 0.2 .mu.T.
Assuming that the power line is 1 .mu.T, the total field near the center will
(if the coil field is in phase with the power line field) change from 1.2 .mu.T
to 1.5 .mu.T and back every second. If the fields are out of phase the net field
will vary from 0.5 to 0.75 .mu.T every second. Either of these conditions would
protect the occupants from exposure to the power line field. The above coil
could be combined within an electric blanket so that the blanket would serve
a dual purpose of heating and protecting.
Such mats also may be adapted for use with chairs, or placed on tables or kitchen
counters, or wherever humans or animals spend considerable time.
Conclusion
Upon reading this application many variations and modifications of my method
and apparatus inventions will become apparent to the reader. Therefore, the
scope of my inventions is to be determined from the appended claims.