JP2004357888A

JP2004357888A - Plasma sterilization device and plasma sterilization method

Info

Publication number: JP2004357888A
Application number: JP2003158940A
Authority: JP
Inventors: Hiroshi Karasawa; 寛唐澤; Masaki Takano; 正喜高野; Mamoru Wakabayashi; 守若林; Koji Sawada; 康志澤田
Original assignee: Chiyoda Manufacturing Corp; Matsushita Electric Works Ltd
Current assignee: Panasonic Electric Works Co Ltd; Chiyoda Manufacturing Corp
Priority date: 2003-06-04
Filing date: 2003-06-04
Publication date: 2004-12-24
Anticipated expiration: 2023-06-04
Also published as: JP4160859B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma sterilization device capable of supplying plasma into a sterilization chamber where an object to be sterilized is stored and discharging a gas inside the sterilization chamber, in which the sterilization processing of the object to be sterilized is ended, directly into the atmosphere. <P>SOLUTION: The plasma sterilization device comprises: a pressure resistant container 12 provided with the sterilization chamber 10; a sterilizer supply means 14 for supplying a gaseous sterilizer into the sterilization chamber 10; a non-reactive gas supply means 16 for supplying a non-reactive gas into the sterilization chamber 10; a plasma generator 18 provided on the outside of the pressure resistant container 12 for generating the plasma to be supplied into the sterilization chamber under the atmospheric pressure; and a vacuum pump 20 for discharging the gas inside the sterilization chamber 10. A control part 62 for controlling the sterilizer supply means 14, the non-reactive gas supply means 16, the plasma generator 18 and the vacuum pump 20 is provided so that the plasma is supplied into the sterilization chamber 10 where primary sterilization is performed to the object to be sterilized by the gaseous sterilizer from the sterilizer supply means 14, secondary sterilization is performed to the object to be sterilized and the gaseous sterilizer remaining inside the sterilization chamber 10 is made harmless. Thus, the gas inside the sterilization chamber, in which the sterilization processing of the object is ended, can directly be discharged into the atmosphere to eliminate the need of an exhaust gas decomposer required in a conventional plasma sterilization device, thereby simlifying the structure or the like of the plasma sterilization device and also its maintenance or the like. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明はプラズマ滅菌装置及びプラズマ滅菌方法に関し、更に詳細にはプラズマ発生装置で発生したプラズマを滅菌室内に供給するプラズマ滅菌装置及びプラズマ滅菌方法に関する。
【０００２】
【従来の技術】
医療材や食品等の被滅菌物に対し、非加熱で滅菌を施すことができる滅菌装置として、下記特許文献１にはプラズマ滅菌装置が提案されている。
【０００３】
【特許文献１】
特開平１０−９９４１５号公報（請求項１、図１）
【０００４】
上記特許文献１に提案されているプラズマ滅菌装置の概要を図４に示す。図４に示すプラズマ滅菌装置では、大気圧でプラズマを発生するプラズマ発生装置１００が設けられた第１チャンバ１０２と、被滅菌物１０４，１０４・・が収容された耐圧構造の第２チャンバ１０６とを連結する配管１０８，１０８には、第１チャンバ１０２内のプラズマを含むプラズマ含有気体の第２チャンバ１０６への供給量を制御するバルブ１１０，１１０とコンプレッサー１１２，１１２とが設けられている。
更に、第２チャンバ１０６には、第２チャンバ１０６内の気体を吸排して内部圧力を一定に保持する圧力調整器１１２及び排気ガス分解装置１１４が設けられている。
【０００５】
図４に示すプラズマ滅菌装置の第２チャンバ１０６に収容した被滅菌物１０４，１０４・・に滅菌を施す際には、酸素等の気体と過酸化水素の液体とをプラズマ発生装置１００に供給し、大気圧下でプラズマを発生させて、プラズマ含有気体を第１チャンバ１０２に蓄積する。
第１チャンバ１０２に蓄積されたプラズマ含有気体は、配管１０８，１０８の制御するバルブ１１０，１１０によって流量を制御されつつ、必要に応じてコンプレッサー１１２，１１２を駆動して、真空状態の第２チャンバ１０６に供給される。
プラズマ含有気体が供給された第２チャンバ１０６の圧力を、大気圧よりもやや高い所定圧力に調整した状態を所定時間保持し、被滅菌物１０４，１０４・・に滅菌を施す。
滅被滅菌物１０４，１０４・・の滅菌が終了した後には、第２チャンバ１０６の気体を、圧力調整器１１２を介して排出する。その排出ガス中には、人体に有害なオゾン等が含まれているため、排気ガス分解装置１１４を通過させて無害化処理を行っている。
【０００６】
【発明が解決しようとする課題】
図４に示すプラズマ滅菌装置では、被滅菌物１０４，１０４・・に非加熱で滅菌を施すことができ、熱劣化されやすい医療材や食品等の被滅菌物に滅菌処理を施すことができる。
しかし、図４に示すプラズマ滅菌装置では、滅菌終了後にも、第２チャンバ１０６内に人体に有害なオゾン等が存在するため、第２チャンバ１０６内の気体を直接大気中に排出できず、排気ガス分解装置１１４を通過させて無害化処理を施してから大気中に排出することを要する。
したがって、図４に示すプラズマ滅菌装置では、排気ガス分解装置１１４のメンテナンス等を必要とする他に、排気ガス分解装置１１４の処理性能によってプラズマ滅菌装置の処理能力も左右される。
そこで、本発明の課題は、被滅菌物が収容された滅菌室内にプラズマを供給し、被滅菌物の滅菌処理を終了した滅菌室内の気体を、直接大気中に排出できるプラズマ滅菌装置を提供することにある。
【０００７】
【課題を解決するための手段】
本発明者等は、前記課題を解決すべく検討を重ねた結果、滅菌室内にガス状の過酸化水素を供給して、減圧下で被滅菌物に第１次滅菌を施してから滅菌室内をアルゴンガス又は空気により大気圧近傍に復圧した後、プラズマ発生装置からプラズマを滅菌室内に供給することによって、被滅菌物に対するプラズマによる第２次滅菌を施すと共に、滅菌室内に残留している過酸化水素やオゾン等を無害化でき、滅菌室内のガスを直接大気中に排出できることを見出し、本発明に到達した。
すなわち、本発明は、被滅菌物が収納される滅菌室が設けられた耐圧容器と、前記滅菌室内にガス状の殺菌剤を供給する殺菌剤供給手段と、前記滅菌室内に非反応性ガスを供給する非反応性ガス供給手段と、前記耐圧容器の外部に設けられ、前記滅菌室内に供給するプラズマを大気圧下で発生するプラズマ発生装置と、前記滅菌室内を真空状態とする排気手段とを具備するプラズマ滅菌装置であって、該排気手段によって、内圧が供給される前記ガス状の殺菌剤の蒸気圧以下となるように排気された前記滅菌室内に、前記殺菌剤供給手段によってガス状の殺菌剤を供給して、前記被滅菌物に対して第１次滅菌を施し、前記第１次滅菌を施した滅菌室には、前記非反応性ガス供給手段によって非反応性ガスを供給し、前記滅菌室内が大気圧近傍に到達したとき、前記プラズマ発生装置からプラズマを前記滅菌室内に供給して、前記被滅菌物に対して第２次滅菌を施すと共に、前記滅菌室内に残留するガス状の殺菌剤を無害化するように、前記殺菌剤供給手段、非反応性ガス供給手段、プラズマ発生装置及び排気手段を制御する制御部が設けられていることを特徴とするプラズマ滅菌装置にある。
また、本発明は、被滅菌物を収納した滅菌室内に、ガス状の殺菌剤とプラズマ滅菌装置からのプラズマとを供給し、前記被滅菌物に滅菌を施す際に、該ガス状の殺菌剤の蒸気圧以下となるように排気した、前記被滅菌物を収納した滅菌室に、前記ガス状の殺菌剤を供給して被滅菌物に第１次滅菌を施し、次いで、前記滅菌室に非反応性ガスを供給して大気圧近傍に昇圧した後、前記被滅菌物に対して第２次滅菌を施すと共に、前記滅菌室内に残留するガス状の殺菌剤を無害化するように、前記プラズマ滅菌装置から大気圧下で発生したプラズマを前記滅菌室に供給することを特徴とするプラズマ滅菌方法でもある。
【０００８】
かかる本発明において、滅菌室には、供給されたガス状の殺菌剤の露点温度以上に前記滅菌室内を加熱する加熱手段を設けることによって、滅菌室内に供給された殺菌剤をガス状に保持でき、被滅菌物の内部に充分に殺菌剤を浸透させることができる。
更に、殺菌剤供給手段には、液状の殺菌剤をガス化する気化器を設けることによって、取扱が容易な液状の殺菌剤を用いることができる。かかる殺菌剤としては、過酸化水素を好適に用いることができる。
また、プラズマ発生装置としては、少なくとも一対の対向電極が外接して設けられた反応管に導入されたプラズマ発生用ガスに、前記対向電極の間に交流電界を印加し、大気圧下で生成したプラズマを前記反応管から放出するプラズマ発生装置を好適に用いることができ、プラズマ発生用ガスとしては、アルゴン、ヘリウム、水素、酸素及び窒素から成る群から選ばれた一種又は二種以上から成る混合ガス、或いは前記群から選ばれた一種又は二種以上と水蒸気との混合ガスを好適に用いることができる。
この本願発明で用いる排気手段としては、滅菌室内を減圧状態とする真空ポンプと、前記滅菌室内が加圧状態となったとき、前記真空ポンプをバイパスして前記滅菌室内のガスを排気し、前記滅菌室内を大気圧近傍の圧力に保持するバイパス排気路とを具備する排気手段を好適に用いることができる。
尚、耐圧容器の外部に、第２次滅菌の際に、滅菌室内のガスの少なくとも一部をプラズマ発生装置に供給できるように、前記滅菌室内のガスをプラズマ発生装置との間で循環する循環手段を設けることによって、滅菌室内に残留しているガス状の殺菌剤を更に一層無害化できる。
【０００９】
本発明に係るプラズマ滅菌装置では、真空状態とした滅菌室内に、殺菌剤供給手段によってガス状の殺菌剤を供給して、被滅菌物に対して減圧下で第１次滅菌を施した後、非反応性ガスによって滅菌室内を大気圧近傍まで昇圧する。このため、ガス状の殺菌剤は被滅菌物の内部まで充分に浸透し、被滅菌物の内部の滅菌を充分に施すことができる。
更に、滅菌室内が大気圧近傍に到達したとき、プラズマ発生装置からプラズマを滅菌室内に供給することによって、被滅菌物の表面の滅菌を再度行うと共に、滅菌室内に残留するガス状の殺菌剤を無害化できる。
その結果、ガス状の殺菌剤及びプラズマによって被滅菌物の滅菌を充分を行うことができ、且つ滅菌処理が終了した際に、滅菌室内の気体を大気中に直接排出できる。
【００１０】
【発明の実施の形態】
本発明に係るプラズマ滅菌装置の一例を説明する概略図を図１に示す。図１に示すプラズマ滅菌装置では、被滅菌物が収納される滅菌室１０が設けられた耐圧容器１２と、滅菌室１０内にガス状の殺菌剤として過酸化水素を供給する殺菌剤供給手段１４と、滅菌室１０内に非反応性ガスとしてのアルゴンガスを供給する非反応性ガス供給手段１６と、耐圧容器１２の外部に設けられ、滅菌室１０内に供給するプラズマを大気圧下で発生するプラズマ発生装置１８と、滅菌室１０内を真空状態とする排気手段としての真空ポンプ２０とが設けられている。
この排気手段には、真空ポンプ２０をバイパスするバイパス排気路２７が設けられている。このバイパス排気路２７には、滅菌室１０が加圧状態となったとき、滅菌室１０内のガスの一部を大気中に排出し、滅菌室１０が減圧状態となったとき、大気が滅菌室１０内に流入しない様に、逆止弁２５が設けられている。
殺菌剤供給手段１４では、容器２０の過酸化水素水は、ポンプ２２によって制御弁２４を経由して気化器２６でガス化されて滅菌室１０に供給される。この過酸化水素水は、過酸化水素の濃度が６０％以下、好ましくは３０〜３５％の水溶液を用いることができる。
かかる過酸化水素水を気化する気化器２６は、その内部に加熱装置が設けられていると共に、内部が減圧状態とすることができる。この気化器２６に供給された過酸化水素水をガス化する際には、供給された過酸化水素水を５０〜１００℃、好ましくは６５〜８０℃でガス化するように減圧状態とする。大気圧下で過酸化水素水を蒸発すると、過酸化水素が熱分解するおそれがあるためである。
【００１１】
この様に、蒸発された過酸化水素が供給される滅菌室１０は、供給された過酸化水素の露点温度以上（３５〜８０℃、好ましくは５０〜５５℃）に加熱できるように、ヒータ等の加熱手段が設けられていいる。
また、非反応性ガス供給手段１６には、ガスボンベ（図示せず）のアルゴンガスは、減圧弁２８、逆支弁３０、制御弁３２、フィルタ３４及びニードル弁３６を経由して滅菌室１０に供給される。
更に、真空ポンプ２０は、滅菌室１０内の気体を吸引する際に、制御弁３８を経由して吸引して逆支弁４０を経由して排出する。
尚、滅菌室１０には、空気がフィルタ４２及び制御弁４４を経由して供給される。
【００１２】
図１に示すプラズマ滅菌装置に用いるプラズマ発生装置１８は、プラズマを大気圧下で発生し得るプラズマ発生装置であれば用いることができるが、特開２００１−１４５６８９号公報で提案されたプラズマ発生装置を好適に用いることができる。
かかるプラズマ発生装置１８は、プラズマ発生用ガスに大気圧下での放電によってプラズマを発生するプラズマ発生装置である。このプラズマ発生装置１８を図２に示す。図２に示すプラズマ発生装置１８は、一対の電極５２，５４が反応管５０の外周面に上下に対向して配設されており、電極５２，５４の間に放電空間が形成されている。かかる電極５２，５４を、反応管５０に外接するように設けることによって、滅菌室１０内への金属不純物成分の侵入を防止できる。
この一対の電極５２，５４のうち、電極５２は、高周波を発生する電源５５に接続されて高電圧が印加される高圧電極に形成され、他方の電極５４は、接地されて低電圧となる設置電極に形成されている。
かかる一対の電極５２，５４の内部には、冷媒が流通する流路が形成されており、この流路に冷媒を供給する冷媒供給管５８，５８と、流路から冷媒を排出する冷媒排出管６０，６０とが接続されている。
また、反応管５０の下端部は、先細り形状に形成されたテーパー構造の集束部５６となっており、この集束部５６からはジェット状のプラズマを噴出させることができる。
尚、一対の電極５２，５４間には、周波数が１ｋＨｚ〜２．５ＧＨｚの交流電界を印加することが好ましく、パルス状電界を印加してもよい。
【００１３】
図２に示すプラズマ発生装置１８の反応管５０には、図１に示す様に、プラズマ発生用ガスとして、酸素ボンベ（図示せず）からの酸素ガスとアルゴンボンベ（図示せず）からのアルゴンガスとの混合ガス（以下、単に混合ガスと称することがある）が減圧弁４６及び制御弁４８を経由して供給される。反応管５０に供給された混合ガスは、一対の電極５２，５４の大気圧下での放電によってプラズマ化されて集束部５６から噴出し、滅菌室１０内に供給される。
プラズマ発生装置１８からプラズマが供給される滅菌室１０内の少なくとも一部のガスは、循環手段としてのエジェクタ２９によって滅菌室１０とプラズマ発生装置１８との間で循環できる。このエジェクタ２９は、滅菌室１０に供給される混合ガスによって駆動され、制御弁２３を経由してエジェクタ２９に吸引された滅菌室１０内のガスは、混合ガスと共にプラズマ発生装置１８を経由して滅菌室１０に再供給される。
図１に示すプラズマ滅菌装置には、真空ポンプ２０、ポンプ２２の駆動・停止、制御弁２３，２４、３２，３８，４４，４８の開閉、及びプラズマ発生装置１８の駆動・停止を制御する制御部６２が設けられている。
【００１４】
かかる制御部６２による各部材の制御については、図３に示す滅菌サイクルパターンと共に説明する。図３は、縦軸に滅菌室１０内の圧力を示すと共に、横軸に経時時間を示し、滅菌サイクルパターンを滅菌室１０の圧力の経時変化を示すグラフである。
先ず、制御部６２からは、制御弁３８を開く開信号と真空ポンプ２０を駆動する駆動信号とを発信し、滅菌室１０内の気体を真空ポンプ２０により排気する。
この際に、滅菌室１０内を３５〜８０℃、好ましくは５０〜５５℃に加熱しつつ、滅菌室１０の内圧を、供給されるガス状の殺菌剤の蒸気圧力以下とする。滅菌室１０内の圧力は、圧力計１１によって知ることができる。
ここで、ガス状の殺菌剤として、ガス状の過酸化水素を用いる場合には、滅菌室１０内を過酸化水素の蒸気圧力以下の圧力（真空度）とする。具体的には、滅菌室１０の到達真空度を、０．１３×１０^２〜１．３３×１０^２Ｐａとすることが好ましい（５０℃での過酸化水素の蒸気圧は１３．３×１０^２Ｐａである）。
滅菌室１０内が所定の真空度に到達したとき、制御部６２からは、制御弁３８を閉じる閉信号と真空ポンプ２０を停止する停止信号とを発信すると共に、ポンプ２２を駆動する駆動信号と制御弁３２を開く開信号とを発信し、容器２０内の過酸化水素水を気化器２６でガス状の過酸化水素にして真空状態の滅菌室１０内に供給する。
過酸化水素水の供給量は、滅菌室１０の圧力によって決定され、滅菌室１０の圧力を依然として減圧状態を保持できる量である。この滅菌室１０の圧力は、滅菌室１０の温度と後述する復圧との関係で決定されるが、滅菌室１０が５５℃の場合には、滅菌室１０の圧力が３０×１０^２Ｐａに到達するまで過酸化水素水を供給することが好ましい。
【００１５】
滅菌室１０の圧力が所定圧力に到達したとき、制御部６２からは、制御弁２４を閉じる閉信号とポンプ２２を停止する停止信号とを発信する。
滅菌室１０は、ガス状の過酸化水素で所定圧力に到達した状態を所定時間保持し、滅菌室１０内の被滅菌物に過酸化水素による第１次滅菌を施す。
かかる第１次滅菌を施す所定保持時間が経過したとき、制御部６２からは、制御弁３２を開く開信号を発信し、アルゴンガスを滅菌室１０内に供給して、減圧状態の滅菌室１０を大気圧近傍まで復圧する。かかる復圧によって、ガス状の過酸化水素は、被滅菌物の内部まで充分に浸透して滅菌を施すことができる。
滅菌室１０が所定の圧力まで復圧したとき、制御部６２からは、制御弁３２を閉じる閉信号を発信し、アルゴンガスの滅菌室１０内への供給を停止する。
更に、滅菌室１０の圧力を、大気圧近傍の所定の圧力で所定時間保持し、ガス状の過酸化水素が被滅菌物の内部に更に一層の浸透を図る。
【００１６】
滅菌室１０の圧力を大気圧近傍の所定圧力で所定時間保持した後、制御部６２からは、プラズマ発生装置１８の一対の電極５２，５４に通電を開始する信号と制御弁４８を開く開信号とを発信し、大気圧下で発生したプラズマを滅菌室１０内に送り込む。
この際に、酸素ボンベ（図示せず）からの酸素ガスとアルゴンボンベ（図示せず）からのアルゴンガスとの混合ガスが、プラズマ発生装置１８の反応管５０に供給され、一対の電極５２，５４の大気圧下での放電によってプラズマ化されて集束部５６から噴出し、滅菌室１０内に供給される。
集束部５６からは噴出されたジェット状のプラズマには、短寿命のラジカル等の反応性ガス活性粒子も含まれており、プラズマが被滅菌物に衝突して第２次滅菌を施すと共に、滅菌室１０内に残存する過酸化水素を分解する。
かかる第２次滅菌の際に、プラズマ発生装置１８に供給される混合ガスによってエジェクタ２９が駆動されているため、制御部６２からの開信号で制御弁２３が開いたとき、滅菌室１０内のガスがエジェクタ２９に吸引されてプラズマ発生装置１８に混合ガスと共に供給されて滅菌室１０に戻る。この様に、滅菌室１０内のガスを、滅菌室１０とプラズマ発生装置１８との間を循環することによって、滅菌室１０内に残存する過酸化水素の分解を更に一層完全なものにできる。
かかるプラズマの滅菌室１０内への送り込みを所定時間行い、滅菌室１０内に残存する過酸化水素を充分に分解した後、制御部６２からは、プラズマ発生装置１８の一対の電極５２，５４への通電を停止する信号と制御弁２３，４８を閉じる閉信号とを発信し、第１回目の滅菌サイクルを終了する。
【００１７】
ところで、プラズマ発生装置１８に供給された混合ガスは、プラズマ発生装置１８でプラズマ化されて滅菌室１０に供給されるため、滅菌室１０内の圧力が大気圧以上に加圧状態となることがある。このとき、滅菌室１０内のガスは、真空ポンプ２０をバイパスするバイパス排気路２７の逆止弁２５を経由して大気中に排出される。この様にして排出される滅菌室１０内のガスは、プラズマ発生装置１８からのプラズマが照射されており、且つその排気量は少量であるため、人体等に対する安全性には問題ない。
【００１８】
通常の滅菌処理では、第１回目の滅菌サイクルの終了では滅菌処理は終了せず、滅菌サイクルが複数回繰り返して行われる。このため、制御部６２からは、制御弁３８を開く開信号と真空ポンプ２０を駆動する駆動信号とを再度発信して、滅菌室１０内の気体を真空ポンプ２０により排気し、滅菌室１０の内圧を、再度、供給されるガス状の殺菌剤の蒸気圧力以下とする。
この際に、真空ポンプ２０からの排気は、特別な処理を施すことなく直接大気中に放出できる。滅菌室１０内には、前回の滅菌操作で用いたアルゴン等の気体が充填されているが、殺菌剤として用いたガス状の過酸化水素の残留分は、前回の滅菌操作でのプラズマの供給によって分解されており、滅菌室１０内の気体を直接大気中に放出しても、人体等に何等悪影響を与えないからである。
次いで、同様な操作を繰り返し、所定回数の滅菌サイクルを繰り返した後、制御部６２からは、制御弁４４を開く開信号を発信し、真空状態の滅菌室１０内にフィルタ４２を経由した空気がフィルタ４２及び制御弁４４を経由して供給して大気圧近傍まで復圧する。
更に、制御部６２からは、制御弁３８を開く開信号と真空ポンプ２０を駆動する駆動信号とを発信して、滅菌室１０内の空気を真空ポンプ２０により排気し、滅菌室１０を再度真空状態とする。
かかる空気の供給及び真空とを繰り返して、滅菌室１０及び被滅菌物を空気に置換して、一連の滅菌を終了する。
この様な、図１〜図３に示すプラズマ滅菌装置を用い、Ｔｙｖｅｋ包装のプラスチック製器具での殺菌実験を行ったところ、１０^６個のＢ．ｓｔｅａｒｏｔｈｅｒｍｏｐｈｉｌｕｓ胞子を滅菌できることを確認できた。
【００１９】
図１〜図３のプラズマ滅菌装置では、プラズマ発生用ガスとして、アルゴンガスと酸素ガスとの混合ガスを用いたが、アルゴン、ヘリウム、水素、酸素及び窒素から成る群から選ばれた一種又は二種以上から成る混合ガス、或いはこの群から選ばれた一種又は二種以上と水蒸気との混合ガスを用いることができる。
かかるプラズマ発生用ガスとしては、図１〜図３のプラズマ滅菌装置で用いたアルゴンガスと酸素ガスとの混合ガスの他に、アルゴンガス、ヘリウムガス及び酸素ガスの混合ガスを好適に用いることができる。具体的には、アルゴンガス９７．５ｖｏｌ％及び酸素ガス２．５ｖｏｌ％から成る混合ガス、或いはアルゴンガス８０．６ｖｏｌ％、ヘリウムガス１６．１ｖｏｌ％及び酸素ガス３．３ｖｏｌ％から成る混合ガスを用いることができる。
更に、図１〜図３のプラズマ滅菌装置で用いるガス状の殺菌剤としては、過酸化水素を用いていたが、プラズマ処理によって安全な物質に分解し得る殺菌剤を用いることができる。かかる殺菌剤としては、例えば過酢酸等の過酸化剤、メチルアルコール、エチルアルコール、イソプロピルアルコール等のアルコール、ホルムアルデヒド、エチレンオキサイド、グルタラールアルデヒド等のアルキル化剤を挙げることができる。
【００２０】
また、図１〜図３のプラズマ滅菌装置では、循環手段として滅菌室１０に供給される混合ガスによって駆動されエジェクタ２９を用いているが、エジェクタ２９に代えて電動駆動のポンプを用いることができる。かかるポンプを用いることによって、図３に示すプラズマ導入工程において、プラズマ発生装置１８を経由して滅菌室１０に供給する混合ガス量を低減でき、バイパス排気路２７を経由して滅菌室１０から大気中に排気される排気量の低減を図ることができる。
尚、滅菌室１０内のガスを滅菌室１０とプラズマ発生装置１８との間で循環しなくても、滅菌終了後に排気する排気中のガス状の殺菌剤を実質的に皆無にできる場合には、制御弁２３を閉じた状態で一連の滅菌を行ってもよい。
【００２１】
【発明の効果】
本発明によれば、被滅菌物の滅菌処理を終了した滅菌室内の気体を、直接大気中に排出できる。
このため、従来のプラズマ滅菌装置では必要としていた排気ガス分解装置を不要にでき、プラズマ滅菌装置の構造等を簡略できると共に、そのメンテナンス等も簡易化できる。
更に、従来のプラズマ滅菌装置の如く、排気ガス分解装置の能力でプラズマ滅菌装置の処理能力が左右されることがなく、プラズマ滅菌装置の処理能力の向上を図ることができる。
【図面の簡単な説明】
【図１】本発明に係るプラズマ滅菌装置の概要を説明する概要図である。
【図２】図１に示すプラズマ滅菌装置に用いるプラズマ発生装置を説明するための正面図である。
【図３】図１に示すプラズマ滅菌装置の滅菌サイクルパターンを説明するための説明図である。
【図４】従来のプラズマ滅菌装置の概略図である。
【符号の説明】
１０滅菌室
１４殺菌剤供給手段
１６非反応性ガス供給手段
１８プラズマ発生装置
２０真空ポンプ
２２ポンプ
２４，３２，３８，４４，４８制御弁
２６気化器
５０反応管
５２，５４電極
５５電源
５６集束部
６２制御部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plasma sterilization apparatus and a plasma sterilization method, and more particularly, to a plasma sterilization apparatus and a plasma sterilization method for supplying plasma generated by a plasma generator into a sterilization chamber.
[0002]
[Prior art]
Patent Document 1 listed below proposes a plasma sterilization apparatus as a sterilization apparatus capable of sterilizing an object to be sterilized such as a medical material or food without heating.
[0003]
[Patent Document 1]
JP-A-10-99415 (Claim 1, FIG. 1)
[0004]
FIG. 4 shows an outline of the plasma sterilizer proposed in Patent Document 1. In the plasma sterilizer shown in FIG. 4, a first chamber 102 provided with a plasma generator 100 for generating plasma at atmospheric pressure, and a second chamber 106 having a pressure-resistant structure containing objects 104,... Are provided with valves 110 and 110 and compressors 112 and 112 for controlling the supply amount of the plasma-containing gas including the plasma in the first chamber 102 to the second chamber 106.
Further, the second chamber 106 is provided with a pressure regulator 112 and an exhaust gas decomposition device 114 for sucking and discharging the gas in the second chamber 106 to keep the internal pressure constant.
[0005]
When sterilizing the objects 104 to be sterilized contained in the second chamber 106 of the plasma sterilization apparatus shown in FIG. 4, a gas such as oxygen and a liquid of hydrogen peroxide are supplied to the plasma generation apparatus 100. A plasma is generated under the atmospheric pressure, and the gas containing the plasma is accumulated in the first chamber 102.
While the flow rate of the plasma-containing gas stored in the first chamber 102 is controlled by the valves 110, 110 controlled by the pipes 108, 108, the compressors 112, 112 are driven as necessary, and the second chamber in a vacuum state is driven. 106.
The state in which the pressure of the second chamber 106 supplied with the plasma-containing gas is adjusted to a predetermined pressure slightly higher than the atmospheric pressure is maintained for a predetermined time, and the objects to be sterilized 104 are sterilized.
After the sterilization of the sterilized objects 104, 104,... Is completed, the gas in the second chamber 106 is discharged via the pressure regulator 112. Since the exhaust gas contains ozone and the like harmful to the human body, the exhaust gas is passed through the exhaust gas decomposition device 114 to perform detoxification processing.
[0006]
[Problems to be solved by the invention]
In the plasma sterilization apparatus shown in FIG. 4, the objects to be sterilized 104, 104,... Can be sterilized without heating, and the objects to be sterilized, such as medical materials and foods, which are easily thermally degraded, can be sterilized.
However, in the plasma sterilization apparatus shown in FIG. 4, even after the sterilization is completed, ozone and the like harmful to the human body are present in the second chamber 106, so that the gas in the second chamber 106 cannot be directly discharged to the atmosphere. After passing through the gas decomposer 114 to perform detoxification treatment, it is necessary to discharge the gas into the atmosphere.
Therefore, in the plasma sterilizer shown in FIG. 4, in addition to requiring maintenance of the exhaust gas decomposition device 114, the processing performance of the plasma sterilizer also depends on the processing performance of the exhaust gas decomposition device 114.
Accordingly, an object of the present invention is to provide a plasma sterilization apparatus capable of supplying plasma to a sterilization chamber containing an object to be sterilized and discharging gas in the sterilization chamber after sterilization of the object to be sterilized directly to the atmosphere. It is in.
[0007]
[Means for Solving the Problems]
As a result of repeated studies to solve the above-described problems, the present inventors supply gaseous hydrogen peroxide into the sterilization chamber, perform primary sterilization on the object to be sterilized under reduced pressure, and then perform the inside of the sterilization chamber. After the pressure is restored to near the atmospheric pressure with argon gas or air, the plasma is supplied from the plasma generator into the sterilization chamber, whereby the object to be sterilized is subjected to the secondary sterilization by the plasma, and the excess remaining in the sterilization chamber. The present inventors have found that hydrogen oxide, ozone, and the like can be rendered harmless, and that gas in a sterilization chamber can be directly discharged to the atmosphere.
That is, the present invention provides a pressure-resistant container provided with a sterilization chamber for accommodating an object to be sterilized, a germicide supply means for supplying a gaseous germicide into the sterilization chamber, and a non-reactive gas in the sterilization chamber. A non-reactive gas supply unit for supplying, a plasma generator provided outside the pressure-resistant container and generating plasma supplied to the sterilization chamber at atmospheric pressure, and an exhaust unit for evacuating the sterilization chamber to a vacuum state. A plasma sterilizing apparatus comprising: a gaseous disinfectant supplied by the disinfectant supply means into the sterilization chamber that is exhausted by the exhaust means so that the internal pressure is reduced to a vapor pressure of the gaseous disinfectant to be supplied. A sterilizing agent is supplied, the object to be sterilized is subjected to primary sterilization, and a non-reactive gas is supplied to the sterilization chamber subjected to the primary sterilization by the non-reactive gas supply means, The sterilization chamber is near atmospheric pressure When it arrives, plasma is supplied from the plasma generator into the sterilization chamber to perform secondary sterilization on the object to be sterilized, and to render gaseous germicides remaining in the sterilization chamber harmless. And a control unit for controlling the bactericide supply unit, the non-reactive gas supply unit, the plasma generator and the exhaust unit.
Further, the present invention also provides a gas sterilizing agent and a plasma from a plasma sterilization apparatus which supply a gaseous sterilizing agent and a plasma from a plasma sterilizer into a sterilizing chamber accommodating the object to be sterilized. The gaseous germicide is supplied to a sterilization chamber containing the object to be sterilized, which has been evacuated to have a vapor pressure of not more than, and the object to be sterilized is subjected to primary sterilization. After supplying a reactive gas and increasing the pressure to around the atmospheric pressure, the object to be sterilized is subjected to a second sterilization, and the plasma is formed so as to render the gaseous germicide remaining in the sterilization chamber harmless. A plasma sterilization method is also characterized in that plasma generated from a sterilizer under atmospheric pressure is supplied to the sterilization chamber.
[0008]
In the present invention, the sterilizing chamber is provided with a heating means for heating the sterilizing chamber above the dew point of the supplied gaseous sterilizing agent, whereby the sterilizing agent supplied into the sterilizing chamber can be maintained in a gaseous state. In addition, the germicide can be sufficiently penetrated into the object to be sterilized.
Further, by providing a vaporizer for gasifying the liquid sterilant in the sterilizing agent supply means, it is possible to use a liquid sterilizer which is easy to handle. Hydrogen peroxide can be suitably used as such a disinfectant.
Further, as a plasma generator, an AC electric field was applied between the opposed electrodes to a plasma generating gas introduced into a reaction tube provided with at least a pair of opposed electrodes circumscribing, and generated under atmospheric pressure. A plasma generator that emits plasma from the reaction tube can be preferably used, and the plasma generating gas is a mixture of one or more selected from the group consisting of argon, helium, hydrogen, oxygen, and nitrogen. A gas or a mixed gas of one or more selected from the above group and water vapor can be suitably used.
As the exhaust means used in the present invention, a vacuum pump for reducing the pressure in the sterilization chamber and, when the sterilization chamber is in a pressurized state, the gas in the sterilization chamber is exhausted by bypassing the vacuum pump. Exhaust means having a bypass exhaust passage for maintaining the pressure in the sterilization chamber at a pressure near the atmospheric pressure can be suitably used.
In addition, the circulation in which the gas in the sterilization chamber is circulated with the plasma generator so that at least a part of the gas in the sterilization chamber can be supplied to the plasma generator during the second sterilization outside the pressure vessel. By providing the means, the gaseous germicide remaining in the sterilization chamber can be made even more harmless.
[0009]
In the plasma sterilization apparatus according to the present invention, a gaseous bactericide is supplied by a bactericide supply unit into a sterilization chamber in a vacuum state, and the object to be sterilized is subjected to primary sterilization under reduced pressure, The pressure inside the sterilization chamber is increased to near atmospheric pressure by a non-reactive gas. For this reason, the gaseous germicide sufficiently penetrates into the object to be sterilized, and the inside of the object to be sterilized can be sufficiently sterilized.
Further, when the inside of the sterilization chamber reaches the vicinity of the atmospheric pressure, the surface of the object to be sterilized is again sterilized by supplying plasma from the plasma generator into the sterilization chamber, and the gaseous germicide remaining in the sterilization chamber is removed. Can be harmless.
As a result, the object to be sterilized can be sufficiently sterilized with the gaseous germicide and plasma, and when the sterilization process is completed, the gas in the sterilization chamber can be directly discharged to the atmosphere.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a schematic diagram illustrating an example of the plasma sterilizer according to the present invention. In the plasma sterilization apparatus shown in FIG. 1, a pressure-resistant container 12 provided with a sterilization chamber 10 for accommodating an object to be sterilized, and a sterilizing agent supply means 14 for supplying hydrogen peroxide as a gaseous sterilizing agent into the sterilizing chamber 10. A non-reactive gas supply means 16 for supplying argon gas as a non-reactive gas into the sterilization chamber 10; and a plasma provided outside the pressure-resistant container 12 and supplied to the sterilization chamber 10 under atmospheric pressure. And a vacuum pump 20 as an exhaust means for evacuating the inside of the sterilization chamber 10.
This exhaust means is provided with a bypass exhaust path 27 that bypasses the vacuum pump 20. When the sterilization chamber 10 is in a pressurized state, a part of the gas in the sterilization chamber 10 is exhausted to the atmosphere when the sterilization chamber 10 is in a pressurized state. A check valve 25 is provided so as not to flow into the chamber 10.
In the disinfectant supply means 14, the hydrogen peroxide solution in the container 20 is gasified by the vaporizer 26 via the control valve 24 by the pump 22 and supplied to the sterilization chamber 10. As this hydrogen peroxide solution, an aqueous solution having a concentration of hydrogen peroxide of 60% or less, preferably 30 to 35% can be used.
The vaporizer 26 for vaporizing the hydrogen peroxide solution has a heating device provided therein, and the inside thereof can be reduced in pressure. When the hydrogen peroxide solution supplied to the vaporizer 26 is gasified, the hydrogen peroxide solution is reduced in pressure so as to gasify the supplied hydrogen peroxide at 50 to 100 ° C., preferably 65 to 80 ° C. This is because, if the hydrogen peroxide solution is evaporated under the atmospheric pressure, the hydrogen peroxide may be thermally decomposed.
[0011]
As described above, the sterilization chamber 10 to which the evaporated hydrogen peroxide is supplied is provided with a heater or the like so that it can be heated to a temperature higher than the dew point temperature of the supplied hydrogen peroxide (35 to 80 ° C., preferably 50 to 55 ° C.). Heating means are provided.
In addition, the non-reactive gas supply means 16 supplies the argon gas from the gas cylinder (not shown) to the sterilization chamber 10 via the pressure reducing valve 28, the check valve 30, the control valve 32, the filter 34 and the needle valve 36. Is done.
Further, when sucking the gas in the sterilization chamber 10, the vacuum pump 20 sucks the gas through the control valve 38 and discharges the gas through the check valve 40.
In addition, air is supplied to the sterilization chamber 10 via the filter 42 and the control valve 44.
[0012]
The plasma generator 18 used in the plasma sterilizer shown in FIG. 1 can be used as long as it can generate plasma at atmospheric pressure, but the plasma generator proposed in JP-A-2001-145689 can be used. Can be suitably used.
The plasma generator 18 is a plasma generator that generates plasma by discharging a plasma generating gas under atmospheric pressure. This plasma generator 18 is shown in FIG. In the plasma generator 18 shown in FIG. 2, a pair of electrodes 52 and 54 are vertically arranged on the outer peripheral surface of the reaction tube 50, and a discharge space is formed between the electrodes 52 and 54. By providing the electrodes 52 and 54 so as to circumscribe the reaction tube 50, entry of metal impurity components into the sterilization chamber 10 can be prevented.
Of the pair of electrodes 52, 54, the electrode 52 is connected to a power supply 55 that generates a high frequency and is formed as a high voltage electrode to which a high voltage is applied, and the other electrode 54 is grounded and has a low voltage. It is formed on the electrode.
A flow path through which the refrigerant flows is formed inside the pair of electrodes 52, 54. A refrigerant supply pipe 58, 58 that supplies the refrigerant to the flow path, and a refrigerant discharge pipe that discharges the refrigerant from the flow path. 60 and 60 are connected.
The lower end of the reaction tube 50 is a converging portion 56 having a tapered structure formed in a tapered shape, and jet plasma can be ejected from the converging portion 56.
Note that an AC electric field having a frequency of 1 kHz to 2.5 GHz is preferably applied between the pair of electrodes 52 and 54, and a pulsed electric field may be applied.
[0013]
As shown in FIG. 1, oxygen gas from an oxygen cylinder (not shown) and argon gas from an argon cylinder (not shown) are provided in the reaction tube 50 of the plasma generator 18 shown in FIG. A mixed gas with the gas (hereinafter, sometimes simply referred to as a mixed gas) is supplied via a pressure reducing valve 46 and a control valve 48. The mixed gas supplied to the reaction tube 50 is turned into plasma by the discharge of the pair of electrodes 52 and 54 under atmospheric pressure, is ejected from the focusing unit 56, and is supplied into the sterilization chamber 10.
At least a part of the gas in the sterilization chamber 10 to which the plasma is supplied from the plasma generator 18 can be circulated between the sterilization chamber 10 and the plasma generator 18 by an ejector 29 as a circulating means. The ejector 29 is driven by the mixed gas supplied to the sterilization chamber 10, and the gas in the sterilization chamber 10 sucked into the ejector 29 via the control valve 23 passes through the plasma generator 18 together with the mixed gas. It is resupplied to the sterilization chamber 10.
The plasma sterilizer shown in FIG. 1 includes a control for controlling the driving and stopping of the vacuum pump 20 and the pump 22, the opening and closing of the control valves 23, 24, 32, 38, 44 and 48, and the driving and stopping of the plasma generator 18. A part 62 is provided.
[0014]
The control of each member by the control unit 62 will be described together with the sterilization cycle pattern shown in FIG. FIG. 3 is a graph showing the pressure in the sterilization chamber 10 on the vertical axis and the aging time on the horizontal axis, and showing the sterilization cycle pattern and the temporal change of the pressure in the sterilization chamber 10.
First, from the control unit 62, an open signal for opening the control valve 38 and a drive signal for driving the vacuum pump 20 are transmitted, and the gas in the sterilization chamber 10 is exhausted by the vacuum pump 20.
At this time, the inside pressure of the sterilization chamber 10 is set to be equal to or lower than the vapor pressure of the supplied gaseous sterilant while the inside of the sterilization chamber 10 is heated to 35 to 80 ° C., preferably 50 to 55 ° C. The pressure in the sterilization chamber 10 can be known by a pressure gauge 11.
Here, when using gaseous hydrogen peroxide as the gaseous germicide, the inside of the sterilization chamber 10 is set to a pressure (vacuum degree) equal to or lower than the vapor pressure of hydrogen peroxide. Specifically, it is preferable that the ultimate vacuum of the sterilization chamber 10 is 0.13 × 10 ^{2 to} 1.33 × 10 ² Pa (the vapor pressure of hydrogen peroxide at 50 ° C. is 13.3 × 10 2 ² Pa).
When the inside of the sterilization chamber 10 reaches a predetermined degree of vacuum, the control unit 62 sends a close signal for closing the control valve 38 and a stop signal for stopping the vacuum pump 20, and a drive signal for driving the pump 22. An open signal to open the control valve 32 is transmitted, and the hydrogen peroxide solution in the container 20 is converted into gaseous hydrogen peroxide by the vaporizer 26 and supplied into the sterilization chamber 10 in a vacuum state.
The supply amount of the hydrogen peroxide solution is determined by the pressure in the sterilization chamber 10, and is an amount that can keep the pressure in the sterilization chamber 10 reduced. The pressure in the sterilization chamber 10 is determined based on the relationship between the temperature of the sterilization chamber 10 and the return pressure described later. When the temperature of the sterilization chamber 10 is 55 ° C., the pressure in the sterilization chamber 10 becomes 30 × 10 ² Pa. It is preferable to supply the hydrogen peroxide solution until it reaches.
[0015]
When the pressure in the sterilization chamber 10 reaches a predetermined pressure, the control unit 62 transmits a close signal for closing the control valve 24 and a stop signal for stopping the pump 22.
The sterilization chamber 10 keeps a state of reaching a predetermined pressure with gaseous hydrogen peroxide for a predetermined time, and performs a first sterilization of the object to be sterilized in the sterilization chamber 10 with hydrogen peroxide.
When the predetermined holding time for performing the primary sterilization has elapsed, the control unit 62 sends an open signal to open the control valve 32, supplies argon gas into the sterilization chamber 10, and controls the sterilization chamber 10 in a reduced pressure state. To near atmospheric pressure. By such a decompression, the gaseous hydrogen peroxide can sufficiently permeate the inside of the object to be sterilized and can be sterilized.
When the pressure in the sterilization chamber 10 is restored to a predetermined pressure, the control unit 62 sends a close signal to close the control valve 32, and stops the supply of the argon gas into the sterilization chamber 10.
Further, the pressure in the sterilization chamber 10 is maintained at a predetermined pressure near the atmospheric pressure for a predetermined time, so that the gaseous hydrogen peroxide permeates further into the object to be sterilized.
[0016]
After maintaining the pressure in the sterilization chamber 10 at a predetermined pressure near the atmospheric pressure for a predetermined time, the control unit 62 outputs a signal to start energizing the pair of electrodes 52 and 54 of the plasma generator 18 and an open signal to open the control valve 48. And the plasma generated under the atmospheric pressure is sent into the sterilization chamber 10.
At this time, a mixed gas of oxygen gas from an oxygen cylinder (not shown) and argon gas from an argon cylinder (not shown) is supplied to the reaction tube 50 of the plasma generator 18, and a pair of electrodes 52, Plasma is generated by the discharge under the atmospheric pressure of 54 and ejected from the focusing section 56, and supplied into the sterilization chamber 10.
The jet-like plasma ejected from the focusing unit 56 also contains reactive gas active particles such as short-lived radicals, and the plasma collides with the object to be sterilized to perform secondary sterilization and sterilization. The hydrogen peroxide remaining in the chamber 10 is decomposed.
During the secondary sterilization, since the ejector 29 is driven by the mixed gas supplied to the plasma generator 18, when the control valve 23 is opened by an open signal from the control unit 62, the inside of the sterilization chamber 10 The gas is sucked by the ejector 29 and supplied to the plasma generator 18 together with the mixed gas, and returns to the sterilization chamber 10. As described above, by circulating the gas in the sterilization chamber 10 between the sterilization chamber 10 and the plasma generator 18, the decomposition of the hydrogen peroxide remaining in the sterilization chamber 10 can be further completed.
After feeding the plasma into the sterilization chamber 10 for a predetermined time and sufficiently decomposing the hydrogen peroxide remaining in the sterilization chamber 10, the control unit 62 sends the plasma to the pair of electrodes 52 and 54 of the plasma generator 18. Then, a signal for stopping the current supply and a close signal for closing the control valves 23 and 48 are transmitted to end the first sterilization cycle.
[0017]
By the way, since the mixed gas supplied to the plasma generator 18 is converted into plasma by the plasma generator 18 and supplied to the sterilization chamber 10, the pressure in the sterilization chamber 10 may be pressurized to the atmospheric pressure or higher. is there. At this time, the gas in the sterilization chamber 10 is discharged into the atmosphere via the check valve 25 of the bypass exhaust path 27 that bypasses the vacuum pump 20. Since the gas in the sterilization chamber 10 discharged in this manner is irradiated with the plasma from the plasma generator 18 and the amount of exhaust gas is small, there is no problem in the safety for the human body or the like.
[0018]
In a normal sterilization process, the sterilization process does not end at the end of the first sterilization cycle, and the sterilization cycle is repeated a plurality of times. For this reason, the control unit 62 transmits an open signal for opening the control valve 38 and a drive signal for driving the vacuum pump 20 again, and exhausts the gas in the sterilization chamber 10 by the vacuum pump 20. The internal pressure is again reduced to the vapor pressure of the supplied gaseous germicide.
At this time, the exhaust from the vacuum pump 20 can be directly discharged to the atmosphere without performing any special treatment. The sterilization chamber 10 is filled with a gas such as argon used in the previous sterilization operation, and the residual gaseous hydrogen peroxide used as a sterilizing agent is supplied by the plasma in the previous sterilization operation. This is because, even if the gas in the sterilization chamber 10 is directly released into the atmosphere, it has no adverse effect on the human body or the like.
Next, the same operation is repeated, and after repeating a predetermined number of sterilization cycles, an open signal for opening the control valve 44 is transmitted from the control unit 62, and the air that has passed through the filter 42 into the sterilization chamber 10 in a vacuum state is sent. The pressure is supplied through the filter 42 and the control valve 44 and the pressure is restored to near the atmospheric pressure.
Further, from the control unit 62, an open signal for opening the control valve 38 and a drive signal for driving the vacuum pump 20 are transmitted, the air in the sterilization chamber 10 is exhausted by the vacuum pump 20, and the sterilization chamber 10 is evacuated again. State.
The supply of air and the vacuum are repeated to replace the sterilization chamber 10 and the object to be sterilized with air, thereby completing a series of sterilization.
Such, a plasma sterilization apparatus shown in FIGS. 1 to 3 was subjected to sterilization experiments in plastic instrument Tyvek packaging, 10 ⁶ B. It was confirmed that stearothermophilus spores could be sterilized.
[0019]
In the plasma sterilization apparatus shown in FIGS. 1 to 3, a mixed gas of argon gas and oxygen gas was used as the plasma generating gas, but one or two selected from the group consisting of argon, helium, hydrogen, oxygen and nitrogen were used. It is possible to use a mixed gas composed of more than one kind, or a mixed gas of one or more kinds selected from this group and water vapor.
As such a plasma generating gas, in addition to the mixed gas of argon gas and oxygen gas used in the plasma sterilizer of FIGS. 1 to 3, a mixed gas of argon gas, helium gas and oxygen gas is preferably used. it can. Specifically, a mixed gas composed of 97.5 vol% of argon gas and 2.5 vol% of oxygen gas, or a mixed gas composed of 80.6 vol% of argon gas, 16.1 vol% of helium gas, and 3.3 vol% of oxygen gas is used. be able to.
Further, as the gaseous germicide used in the plasma sterilizer shown in FIGS. 1 to 3, hydrogen peroxide is used, but a germicide which can be decomposed into a safe substance by plasma treatment can be used. Examples of such disinfectants include peroxidants such as peracetic acid, alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, and alkylating agents such as formaldehyde, ethylene oxide and glutaraldehyde.
[0020]
In addition, in the plasma sterilization apparatus shown in FIGS. 1 to 3, the ejector 29 driven by the mixed gas supplied to the sterilization chamber 10 is used as a circulating means, but an electrically driven pump can be used instead of the ejector 29. . By using such a pump, in the plasma introduction step shown in FIG. 3, the amount of the mixed gas supplied to the sterilization chamber 10 via the plasma generator 18 can be reduced. The amount of exhaust gas exhausted inside can be reduced.
In addition, when the gas in the sterilization chamber 10 can be substantially eliminated from the gaseous germicide in the exhaust air that is exhausted after the sterilization without circulating the gas in the sterilization chamber 10 between the sterilization chamber 10 and the plasma generator 18. A series of sterilization may be performed with the control valve 23 closed.
[0021]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the gas in the sterilization chamber which completed the sterilization process of the to-be-steriled object can be discharged | emitted directly to air | atmosphere.
For this reason, the exhaust gas decomposer required in the conventional plasma sterilizer can be omitted, and the structure and the like of the plasma sterilizer can be simplified, and the maintenance and the like can be simplified.
Further, unlike the conventional plasma sterilization apparatus, the processing capacity of the plasma sterilization apparatus is not affected by the capacity of the exhaust gas decomposition apparatus, and the processing capacity of the plasma sterilization apparatus can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating an outline of a plasma sterilizer according to the present invention.
FIG. 2 is a front view for explaining a plasma generator used in the plasma sterilizer shown in FIG.
FIG. 3 is an explanatory diagram for explaining a sterilization cycle pattern of the plasma sterilization apparatus shown in FIG.
FIG. 4 is a schematic view of a conventional plasma sterilizer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Sterilization room 14 Sterilizer supply means 16 Non-reactive gas supply means 18 Plasma generator 20 Vacuum pump 22 Pumps 24, 32, 38, 44, 48 Control valve 26 Vaporizer 50 Reaction tube 52, 54 Electrode 55 Power supply 56 Focusing unit 62 control unit

Claims

A pressure-resistant container provided with a sterilization chamber for accommodating an object to be sterilized, a disinfectant supply means for supplying a gaseous disinfectant into the sterilization chamber, and a non-reactive gas for supplying a non-reactive gas into the sterilization chamber A plasma generator provided outside of the pressure-resistant container and configured to generate plasma supplied to the sterilization chamber under atmospheric pressure, and an exhaust unit configured to exhaust gas in the sterilization chamber. So,
A gaseous germicide is supplied by the germicide supply means into the sterilization chamber evacuated by the evacuating means to a vapor pressure of the gaseous germicide to which the internal pressure is supplied, and the gaseous germicide is supplied. Perform the first sterilization on the sterilized material,
A non-reactive gas is supplied to the sterilization chamber subjected to the primary sterilization by the non-reactive gas supply means, and when the sterilization chamber reaches near atmospheric pressure, the plasma is sterilized from the plasma generator. The germicide supply means, the non-reactive gas supply, so as to perform secondary sterilization on the object to be sterilized by supplying the germicide to the room and detoxifying the gaseous germicide remaining in the sterilization chamber; A plasma sterilizing apparatus, comprising: a control unit for controlling a unit, a plasma generator, and an exhaust unit.

The plasma sterilization apparatus according to claim 1, wherein the sterilization chamber is provided with heating means for heating the sterilization chamber to a temperature equal to or higher than the dew point temperature of the supplied gaseous germicide.

The plasma sterilizer according to claim 1 or 2, wherein the disinfectant supply means is provided with a vaporizer for gasifying a liquid disinfectant.

The plasma sterilizer according to any one of claims 1 to 3, wherein the germicide is hydrogen peroxide.

A plasma generator applies an AC electric field between the opposed electrodes to a plasma generating gas introduced into a reaction tube provided with at least a pair of opposed electrodes circumscribing, and generates plasma generated under atmospheric pressure. The plasma sterilizer according to any one of claims 1 to 4, which is a plasma generator that emits from a reaction tube.

The gas for plasma generation is a mixed gas of one or more selected from the group consisting of argon, helium, hydrogen, oxygen and nitrogen, or a mixed gas of one or two or more selected from the group and water vapor The plasma sterilizer according to claim 5, wherein

The evacuation means includes a vacuum pump for reducing the pressure in the sterilization chamber, and, when the sterilization chamber is in a pressurized state, evacuating the gas in the sterilization chamber by bypassing the vacuum pump and controlling the pressure in the sterilization chamber to atmospheric pressure. The plasma sterilization apparatus according to any one of claims 1 to 6, further comprising a bypass exhaust passage for maintaining a pressure in the vicinity.

Circulating means for circulating the gas in the sterilization chamber with the plasma generator so that at least part of the gas in the sterilization chamber can be supplied to the plasma generator during the second sterilization, outside the pressure-resistant container; The plasma sterilizer according to any one of claims 1 to 7, further comprising:

When supplying a gaseous germicide and plasma from a plasma sterilizer to the sterilization chamber containing the object to be sterilized, and sterilizing the object to be sterilized,
The gaseous disinfectant is evacuated to a vapor pressure of the gaseous disinfectant or less, and the gaseous disinfectant is supplied to a sterilization chamber accommodating the object to be sterilized to perform primary sterilization on the object to be sterilized,
Then, after supplying a non-reactive gas to the sterilization chamber and increasing the pressure to near the atmospheric pressure, the object to be sterilized is subjected to a second sterilization, and the gaseous germicide remaining in the sterilization chamber is made harmless. A plasma sterilization method comprising: supplying plasma generated under atmospheric pressure from the plasma sterilization apparatus to the sterilization chamber so that the plasma is sterilized.