`
`« UK Patent Application «.». GB «2 176 009 A
`
`(43) Application published 10 Dec 1986
`
`
`(21) Application No 8607762
`(22) Date offiling 27 Mar 1986
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`(30) Priority data
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`(31) 69492
`=(32) 29Mar1985 (33) BG
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`
`
`
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`(51) INT CL*
`G01R 33/02
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`(52) Domestic classification (Edition H):
`G1N 401 402 404 405 422 424 43X 461 463 472
`U1S 1032 2162 G1N
`
`(56) Documentscited
`GB A 2119094
`GB 1416335
`
`US 4489274
`US 3835375
`
`(58) Field of search
`GIN
`Selected US specifications from IPC sub-classes GO1R
`A61B
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`
`
`(71) Applicant
`VMEI“Lenin”(Buigaria),
`Quartal Darvenitza, 1156 Sofia, Bulgaria
`
`(72) Inventors
`Nentcho Georgiev Todorov,
`Dimiter Tzenev Dimitrov,
`Tihomir fliev Manev,
`Georgi Nikolov Dimov,
`Magdatena Davidkova Stefanova
`
`(74) Agent and/or Addressfor Service
`Haseltine Lake & Co, Hazlitt House, 28 Southampton
`Buildings, Chancery Lane, London WC2A 1AT
`
`
`(54) Magnetic field intensity meter
`
`(57) Amagnetic field intensity meter
`comprisesa plurality of local induction
`transducers (14.....14) which can be
`arranged over a patient, a multiplexer
`(2) having its inputs coupled to the local
`induction transducers for coupling their
`outputs in turn to a recording and/or
`detecting device (8), and a safety device
`(9) operable to provide an alarm signal
`if any of the local induction transducers
`provides an indication of a deviation
`from a preset mode of therapy. Each
`transducer may comprise two windings
`of equal number, their common ends
`coupled to neutral and the other ends
`coupled to the inputs of multiplexer (2).
`
`
`
`The drawing(s) originally filed was (were) informal and the print here reproducedis taken fromalaterfiled formal copy.
`
`VY6009/1¢a5
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`GB 2176009 A 1LNrere
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`SPECIFICATION
`
`Magneticfield intensity meter
`
`An exemplary embodimentof the inventionis
`shownin the drawing,Figure 1 being a block-diagram
`of the meter and Figure 2 being a drawing of one of
`the local induction transducers.
`The invention relates to.a magnetic field intensity
`According to Figure 1-the alternating magnetic field
`meter which maybe used in medical applications.
`intensity meter comprises of N local induction
`A magnetic field intensity meter is known
`transducers 14, 12,...1;.....1y, each transducer having
`consisting of an induction transducer whichis
`twowindings with the same number of turns. The
`connecied to a recording block by means of a block
`joint end of the two windingsof eachdifferentiating
`for transforming alternating voltageinto direct
`or differential transducer1;is connected to neutral,
`current. Thus see USSR patent No. 721782.
`the other two ends of the two windingsof each
`The disadvantages of the aforementioned meter
`transducer being connected to the respective
`include the impossibility of obtaining a wide pattern
`N-inputs of a controliable electronic commutator or
`ofthe magneticfield distribution at different points of
`multiplexer 2. The output of a control program block3
`a patient area ora patient body, as well as the absence
`is connected to the control input of the electronic
`commutator 2,
`of an alarm in the caseof a deviation from a preset
`mode of therapy.
`The two outputs of the electronic commutator 2 are
`According to the present invention thereis
`connected respectively to the inputs of two identical
`provided a magnetic field intensity meter comprising
`low-frequencyfilters 4 and 5, whose outputs are
`a plurality of local induction transducers which can be
`connected rerspectively to the noninverting and
`arranged overa patient, a multiplexer having its
`inverting inputs ofa differentiating or differential
`inputs coupied to the local induction transducers for
`amplifier 6. The output of the latter is connected to the
`coupling their outputs in turn to a recording and/or
`input of a block 7 for transformingthe alternating
`detecting device, and a safety device operableto
`voltage into direct current,i.e. an a.c. to d.c.
`25
`90
`provide an alarm signal if any of the local induction
`converter. The block7is connectedto the input ofa
`transducers providesan indication of a deviation
`recording and/or detecting block 8, which is
`from a preset modeof therapy.
`connected to an interlock block 9 whichis itself
`Apreferred embodimentof the invention may
`connected to the interlock or blocking input of
`provide a magnetic field intensity meter providing the
`magnetotherapy apparatus 10. Figure 2 shows
`possibility of getting a full pattern of the magnetic
`winding 11 of alocal induction transducer, the former
`field distribution at different points of the patient area
`being conically wound on a dielectric coil with a
`or the patient body, as well as an alarm for
`square cross-section.
`magnetotherapy apparatus in the case of deviation
`The operation of the alternating magnetic field
`from a preset mode of therapy.
`intensity meter in a magnetotherapy methodis as
`Adetailed embodiment provides a magneticfield
`follows:
`;
`intensity meter including an induction transducer,a
`The local induction transducer1, 13,.....1) are to be
`block for transforming the alternating voltage into
`arranged according to medical requirements in
`direct current, and a recording block connected to an
`specified points ofthe patient area 1,so thatthe
`interlock block input. The interlock block outputis
`bigger base of winding 11 should bein contact with
`connectedto the blocking input of magnetotherapy
`the patient. This guarantees highersensitivity of the
`apparatus. The induction transducer consists of local
`transducers14, 12,.....1yto magnetic signals coming
`induction transducers,the latter being N in number,
`from the patient area, against interfering magnetic
`each one containing two windings with the same
`signals coming from outside during measuring weak
`number of turns, conically wound ona dielectric coil
`magnetic fields. When stronger magnetic signals are
`with a square cross-section. The joint end of the two
`being measuredthe transducers1}, 12,....1y are
`windings of each local induction transducer is
`turned with their small base to the patient. The
`connected to neutral and the other two ends ofthe
`second caseis applied in magnetic signal control of
`two windings are connected correspondingly to the
`some organs of the human body during
`N-inputs of a controllable electronic commutator or
`magnetotherapy.
`multiplexer, to the control input of which the output
`The efficient magnetic signals induce in the two
`of acontro! program block has been connected. The
`windings of each local induction transducer1,,
`two outputs of the controllable electronic
`12,...1y equal and opposite-phased voltages,the latter
`commutator are connected to the inputs of two
`being proportional to the degree of the measured
`low-frequencyfilters whose outputs are connected
`magneticintensity and to the frequencyofthe
`correspondingly to the noninverting and inverting
`magnetic signals. The frequencyof the cut-off points
`inputs of a differentiating or differential amplifier. The
`ofthe low-frequencyfilters 4 and 5is determined by
`amplifier output is connectedto the block for
`the choice of the filter elements in such a waythatitis
`transforming the alternating voltage into direct
`lowerthan the lowest frequencyof the efficient
`current.
`magnetic signal applied in magnetotherapy.
`The advantage of such a magnetic field intensity
`Thus, after passing through filters 4 and 5 the
`meter is the possibility of getting a full pattern ofthe
`information signals sent to both inputs ofthe
`magnetic field distribution at orto various points of
`differentiating amplifier 6 for frequencies higher than
`the patient area or patient body, as well asthe
`the lowest frequencyf,, become
`interlock inthe magnetotherapy apparatus in case of
`frequency-independent. According to the medical
`deviation from the present mode oftherapy.
`requirements a scanning program isset up from the
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`9, Amagneticfield intensity meter substantially
`as hereinbefore described with referenceto the
`accompanying drawing. ©
`10. Ameter according to any preceding claim,
`when coupled to a magnetotherapy apparatus for —
`blockingthe sameby said alarm signal.
`
`Printed inthe UKfor HMSO, pee18035, 10/86, 7102.
`Published byThe Patent Offica, 25 Southampton Buildings, Landon,
`WC2A TAY, fram which copies may be obtained,
`:
`
`2-
`GB 2176009 A’
`2
`icsssnannannnTOSISIEnnerOt
`control program block 3 by means ofthe electronic
`commutator 2. Theinputs ofthelocalinduction
`transducers 1;,12,....1y are thereby applied, in
`“accordance withthe program,in afixedorder and for
`adefinite period of time to the inputs ofthe
`low-frequencyfilters 4 and 5. The intensity ofthe
`magnetic signals Inail N--points ofthe patient areais
`followed for a certainperiod of time which is specified
`for the therapeutical seance or session. The amplified
`voltage from the output of amplifier6 is fedto block7
`10
`_ fortransforming thealternating voltage into direct
`current,whosevalue is proportional to the mean
`valueof the alternating magnetic field intensity at the
`- pointinwhich the corresponding transducer is
`15
`located. Theoutputsignal from block7 isfedto the
`recarding block 8 whichin turn actuates the interlock
`block9.Ifthe value allowedforthe alternating
`“magneticfield is exceededin any ofthe N-points of
`“the patient area, orinthe case of effecting the
`completion ofthe program for the time ofthe >
`therapeutical seance or session, a blockingsignal is
`‘fed from block 9 to the magnetotherapy apparatus 10,
`thus possibly forming or indicating a magneticfield in
`the patient area at which the apparatusis switched
`off.
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`CLAIMS
`1. Amagnetic field intensity meter comprising a
`plurality of local induction transducers which can be
`arranged over apatient, a multiplexerhaving its
`“inputs coupled tothe local induction transducers for
`‘coupling their outputs in turnto a recording and/or
`detecting device, and a safety device operable to
`provide an alarm signalifany of the local induction
`transducers provides an indication of a deviation
`froma preset mode oftherapy.
`:
`2. Ameteraccordingtoclaim 1, whereinthe
`‘safety device is coupled to detect signals from the
`recording and/or detecting device.
`3-° Ameteraccording to-claim1 or2, wherein each
`local induction transducercomprises two windings
`with the same numberofturns, the joint end.ofthe
`- two windings being coupled to neutral and the other
`45 two winding ends being coupledto inputs ofthe
`multiplexer.
`.
`4.
`-Ameter according to claim3, wherein each
`’ focal induction transducerthe windings are wound
`conically on adielectric coil with a substantially ©
`square cross-section.
`5. Ameter according to any preceding claim,
`wherein the multiplexer has a control input coupled
`to.a control program device.
`;. Ameter according to any peceding claim,
`55
`wherein the multiplexer has two outputs connected
`~ to low-frequencyfilters, which are themselves
`‘-. goupledio the inverting and noninverting inputs
`respectively ofa differential amplifier.
`7. _Ameter according to any preceding claim,
`60
`comprising ana.c: to d.c. converter coupled between
`- the transducers andthe recording and/or detecting
`- device.
`8. Ameter according toclaim 7 when appendedto
`claim 6, wherein thea.c. to d.c. converter is connected
`tothe output ofthe differential amplifier.
`65"
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