Apparatus and Method for Electrically Killing Plants

Abstract

Apparatus to electrically kill a plant or at least attenuate plant growth comprising an electrical energy processing unit and an electrical continuity system, the electrical energy processing unit to transmit processed electrical energy between an applicator electrode of an applicator unit and an earth electrode of an earth unit, the electrical continuity system comprising: a signal generator configured to generate a continuity signal and to transmit said signal around a continuity circuit including, or in operational proximity to, one or both of the said electrode(s); a signal processing arrangement configured to at least partially isolate the transmitted continuity signal from the processed electrical energy; a control circuit operable to: determine, using said isolated continuity signal or a property related thereto, an electrical continuity between the ground and one or both of the said electrodes; control, using said determined electrical continuity, the processed electrical energy.

1 . Apparatus to electrically kill a plant or at least attenuate plant growth comprising:
 an electrical energy processing unit to transmit electrical energy between an applicator electrode of an applicator unit and an earth electrode of an earth unit; and   an electrical continuity system comprising:
 a signal generator configured to generate a continuity signal and to transmit said signal around a continuity circuit including, or in operational proximity to, one or both of the said electrode(s); 
 a signal processing arrangement configured to at least partially isolate the transmitted continuity signal from the electrical energy; and 
 a control circuit operable to: determine, using said isolated continuity signal or a property related thereto, an electrical continuity between the ground and one or both of the said electrodes; control, using said determined electrical continuity, the processed electrical energy. 
   
     
     
         2 . The apparatus according to  claim 1 , wherein the electrical energy processing unit comprises:
 a converter configured to receive unprocessed electrical energy from an electrical energy source, to convert the unprocessed electrical energy to processed electrical energy and to output said processed electrical energy to the said electrodes; and   a control circuit operable to control the converter to convert the unprocessed electrical energy to the processed electrical energy.   
     
     
         3 . The apparatus according to  claim 1 , wherein the apparatus comprises an applicator unit and an earth unit comprising the respective applicator and earth electrodes. 
     
     
         4 . The apparatus according to  claim 1 , wherein the continuity circuit comprises first and second continuity electrodes with the continuity signal transmitted therebetween. 
     
     
         5 . The apparatus according to  claim 4 , wherein
 the first and second continuity electrodes have an arrangement selected from one of the following:   the first continuity electrode is incorporated with the applicator electrode and the second continuity electrode is incorporated with the earth electrode;   the first continuity electrode is incorporated with the applicator electrode and the second continuity electrode is arranged in operational proximity to, without being incorporated with, one of the applicator electrode or earth electrode;   the second continuity electrode is incorporated with the earth electrode and the first continuity electrode is arranged in operational proximity to, without being incorporated with, one of the applicator electrode or earth electrode; and   the first continuity electrode is arranged in operational proximity to, without being incorporated with, one of the applicator electrode or earth electrode and the second continuity electrode is arranged in operational proximity to, without being incorporated with, one of the applicator electrode or earth electrode.   
     
     
         6 . The apparatus according to  claim 1 , wherein the electrical energy processing unit and electrical continuity system are configured to generate respective processed electrical energy and continuity signals that can be at least partially filtered from each other by one or more filters of the signal processing arrangement, the filters selected from the group comprising: high-pass; low-pass; band-pass; and band stop. 
     
     
         7 . The apparatus according to  claim 1 , wherein the electrical energy processing unit is configured to generate processed electrical energy:
 that is non-steady and comprises a waveform with a frequency; or   processed electrical energy that is steady.   
     
     
         8 . The apparatus according to  claim 1 , wherein the signal generator is configured to generate:
 a continuity signal that is non-steady and comprises a waveform with a frequency; or   a continuity signal that is steady.   
     
     
         9 . The apparatus according to  claim 7 , wherein the continuity signal comprises a frequency that is different to the frequency of the processed electrical energy or the continuity signal is steady, to enable it to be at least partially filtered from the processed electrical energy by the signal processing arrangement. 
     
     
         10 . The apparatus according to  claim 9 , wherein the difference in frequency is at least 50% or an octave or decade greater or lower. 
     
     
         11 . The apparatus according to  claim 1 , wherein the control circuit is operable to:
 compare the determined electrical continuity to a predetermined condition;   enable the transmission of the processed electrical energy between the applicator electrode and earth electrode if the predetermined condition is satisfied; and/or   prevent the transmission of the processed electrical energy between the applicator electrode and earth electrode if the predetermined condition is not satisfied.   
     
     
         12 . The apparatus according to  claim 1 , wherein said determining of the electrical continuity using the continuity signal comprises the control circuit configured to measure an aspect of the transmitted continuity signal, wherein the aspect is selected from the group consisting of voltage; phase; current; power; and shape of waveform. 
     
     
         13 . The apparatus according to  claim 1 , wherein said determining of the electrical continuity using a property related to the continuity signal comprises the control circuit configured to measure an electrical potential to maintain the continuity signal with a constant current through the electrical continuity circuit. 
     
     
         14 . The apparatus according to  claim 1 , wherein said determining of the electrical continuity using the continuity signal comprises the: signal generator configured to generate a continuity signal that encodes information; the control circuit operable to determine electrical continuity by, for a transmitted continuity signal, decoding and authenticating said information. 
     
     
         15 . The apparatus according to  claim 1 , wherein the signal processing arrangement is configured to prevent the processed electrical energy from interfering with the determination of the electrical continuity. 
     
     
         16 . The apparatus according to  claim 15 , wherein the signal processing arrangement comprises one or more first filters arranged in series with the signal generator of the electrical continuity system, the first filters being configured to allow passing of at least part of the continuity signal and to prevent the passing of at least part of the processed electrical energy. 
     
     
         17 . The apparatus according to  claim 1 , wherein the signal processing arrangement is configured to prevent at least part of the continuity signal being transmitted around a circuit other than the continuity circuit. 
     
     
         18 . The apparatus according to  claim 17 , wherein the signal processing arrangement comprises one or more second filters arranged in series with a converter unit of the converter, the second filters being configured to prevent the passing of at least part of the continuity signal. 
     
     
         19 . A method of electrically killing a plant or at least attenuating plant growth using the apparatus according to  claim 1 , the method comprising:
 transmitting processed electrical energy between an applicator electrode of an applicator unit and an earth electrode of an earth unit;   transmitting a continuity signal to or in operational proximity to one or both of the said electrode(s);   isolating using a signal processing arrangement at least part of the continuity signal from the processed electrical energy;   determining, using said isolated continuity signal or a property related thereto, an electrical continuity between the ground and one or both of the said electrodes; and   controlling, using said determined electrical continuity, the transmission of the processed electrical energy.   
     
     
         20 . The method according to  claim 19 , further comprising:
 encoding information with the continuity signal; and   determining said electrical continuity by decoding and authenticating the encoded information.