Liquid treatment method and liquid treatment apparatus for treating a liquid with plasma

Patent metadata

Field	Value
Publication number	US-9855356-B2
Application number	US-201615141590-A
Country	US
Kind code	B2
Filing date	Apr 28, 2016
Priority date	May 18, 2015
Publication date	Jan 2, 2018
Grant date	Jan 2, 2018

Abstract

A liquid treatment method according to an aspect of the present disclosure comprises: starting application of a power between a pair of electrodes to generate plasma, which causes active species to be produced in a liquid; measuring the hydrogen ion concentration in the liquid while the plasma is generated; measuring a time elapsed after the starting the application of the power; and stopping the application of the power when a value calculated by (a) multiplying the hydrogen ion concentration by the elapsed time or (b) integrating the hydrogen ion concentration with respect to the elapsed time is larger than a first threshold.

First claim

What is claimed is:

1. A liquid treatment method comprising:
starting application of a power between a pair of electrodes positioned in a liquid to generate plasma, which causes active species to be produced in the liquid;
measuring a hydrogen ion concentration in the liquid while the plasma is generated;
measuring a time elapsed after the starting the application of the power; and
stopping the application of the power when a value, calculated by (a) multiplying the hydrogen ion concentration by the elapsed time or (b) integrating the hydrogen ion concentration with respect to the elapsed time, is larger than a first threshold.

2. The liquid treatment method according to claim 1 , further comprising:
adding an acidic substance to the liquid when the value is smaller than a second threshold at a predetermined time, the second threshold being equal to or smaller than the first threshold.

3. A liquid treatment method comprising:
starting application of a power between a pair of electrodes positioned in a liquid to generate plasma, which causes active species to be produced in the liquid;
mixing the first liquid with a liquid to be sterilized to produce a second liquid while the plasma is generated;
measuring a hydrogen ion concentration in the second liquid;
measuring a time elapsed after the mixing the first liquid with the liquid to be sterilized; and
stopping the application of the power when a value, calculated by (a) multiplying the hydrogen ion concentration by the elapsed time or (b) integrating the hydrogen ion concentration with respect to the elapsed time, is larger than a first threshold.

4. A liquid treatment method comprising:
starting application of a power between a pair of electrodes positioned in a liquid to generate plasma, which causes active species to be produced in the liquid;
adding an acidic substance to the liquid while the plasma is generated;
measuring a hydrogen ion concentration in the liquid while the plasma is generated;
measuring a time elapsed after the adding the acidic substance to the liquid; and
stopping the application of the power when a value, calculated by (a) multiplying the hydrogen ion concentration by the elapsed time or (b) integrating the hydrogen ion concentration with respect to the elapsed time, is larger than a first threshold.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Fujikane Masaki
• Onodera Mari
• Okada Yuka

Classifications

• C02F2209/06

  pH · CPC title

• C02F2303/04

  Disinfection · CPC title

• A61L2/14 Primary

  Plasma, i.e. ionised gases · CPC title

• A61L2/24

  Apparatus using programmed or automatic operation · CPC title

• G01N33/28

  Oils {, i.e. hydrocarbon liquids} (edible oils or edible fats G01N33/03) · CPC title