Abstract of patents.
A
method for control of vegetation at places where said vegetation is
undesirable, said method comprising intense irradiation of the vegetation
for one or several periods by light, of which at least 10% of the effect
is ultra-violet light, the total irradiation dosage (joule/m2)
exceeding a minimal value necessary for the intended vegetation control.
An
apparatus for performing the method comprises at least one light source
directed towards the undesired vegetation and emitting at least 10% of its
light discharge in the ultra-violet range, said apparatus comprising means
which after discharge of an irradiation dosage surpassing the minimal
value necessary for the intended vegetation control discontinue the
treatment of the areas in question.
Claims:
1. A
method for control of vegetation at sites where said vegetation is
undesirable which comprises intensely irradiating said sites with light of
which at least 10% is ultra-violet light, wherein the total irradiation
(joule/m2) is sufficient to realize the intended vegetation
control.
2. The method according to
claim 1
including the step of experimentally determining said sufficient amount of
total irradiation in the form of a coherent value set for a given light
source, the time of irradiation, the number of repetitions of irradiation
and the time between subsequent irradiations.
3. The method according to
claim 1
in which at least 5% of the light is within the UVC-range.
4. The method according to
claim 1,
wherein the irradiation is effected from a high light intensity source and
is applied for a short exposure period.
5. The method of
claim 4,
wherein the period of exposure is less than 10 seconds.
6. The method of
claim 5,
wherein the period of exposure is less than 3 seconds.
7. A method of
claim 1,
wherein the site at which said vegetation is undesirable is a railway
track, the irradiation is effected with at least one gas discharge lamp
directed toward said site and mounted on a movable railway carriage and
wherein the railway carriage is moved at a speed which permits application
of said sufficient amount of total irradiation.
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8. The
method of claim 7,
wherein the output of the gas discharge lamp is controllable and said
output is controlled as a function of the travel speed of the movable
railway carriage.
9. A method according to
claim 1,
wherein a source of the light irradiation is connected to an ozone sensor
and a UV light sensor through a control, and the control is set to lower
the level of irradiation when at least one of said sensors exceeds a
predetermined threshold.
10. An apparatus for retarding vegetation in a site and which it is not
desired comprising at least one irradiation light source disposed to
irradiate said site and which emits at least 10% of its light discharge in
the ultra-violet range in combination with means to discontinue
irradiation of said site when the total irradiation (joule/m2)
surpasses a predetermined value.
11. The apparatus of
claim 10,
wherein said irradiation light source is mounted on a movable carriage
which includes drive means for moving the carriage at a speed such that
said predetermined total irradiation is achieved at a given site.
12. The apparatus according to
claim 10,
wherein the irradiation light source is a plurality of substantially
downwardly directed gas discharge lamps mounted on a movable railway
carriage such that light is directed approximately vertically downward.
13. The apparatus according to
claim 12,
wherein at least one lamp is disposed so as to irradiate an area outside
the width of the carriage.
14. An apparatus according to
claim 12,
further comprising an electronic, high-frequency ballast for momentary
control of discharge light intensity coupled to at least one gas discharge
lamp.
15. An apparatus according to
claim 12,
wherein at least one lamp has a filter which reduces light discharge at
wavelength smaller than 250 nm.
16. An apparatus according to
claim 10,
further comprising a registration means to register the light dosages
discharged by the source of irradiation and provided with a computer.
Ref:
US PATENT 05929455 and
EU PATENT EP 0 763 973 B1
Proprietor: Electro Light ApS
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