Method and apparatus for supplying mixed gas

Patent metadata

Field	Value
Publication number	US-9533268-B2
Application number	US-201414511214-A
Country	US
Kind code	B2
Filing date	Oct 10, 2014
Priority date	Apr 13, 2012
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

A method and apparatus, for supplying high-pressure mixed gas of a low-vapor-pressure first gas as an active gas and a high-vapor-pressure second gas, are arranged to reduce an amount of the first gas discarded. The mixed gas in a high-pressure state is supplied from a mixing container to a use point. Upon reduction of pressure in the mixing container to a setpoint as a result of supply to the use point, a predetermined amount of the first gas is charged into a replenishment container connected to the mixing container by a replenishment line having a replenishment valve, and which is evacuated. As the second gas is charged into the replenishment container charged with the first gas, the replenishment valve is opened such that the first gas in the replenishment container is forced out by the second gas, thereby charging the mixing container with the mixed gas in the high-pressure condition.

First claim

The invention claimed is:

1. A method of supplying a mixed gas, in which the mixed gas is prepared by mixing a first gas having a boiling point equal to or higher than 0° C. and equal to or lower than 100° C. and a second gas having a boiling point equal to or lower than −30° C., and in which the mixed gas is supplied to a use point from a mixing container charged with the mixed gas, the method comprising
replenishing the mixing container with the mixed gas when pressure in the mixing container is reduced to a setpoint via supply to the use point,
wherein the replenishing of the mixing container includes
evacuating a replenishment container which is connected to the mixing container,
charging a predetermined amount of the first gas into the replenishment container which is connected to the mixing container by a replenishment line having a replenishment valve, and
charging the second gas into the replenishment container charged with the first gas and simultaneously opening the replenishment valve to cause the first gas in the replenishment container to be forced out by the second gas, whereby the mixing container is replenished with the mixed gas.

2. The method of supplying a mixed gas according to claim 1 , wherein the internal capacity of the replenishment container is equal to or larger than 1/100 of the internal capacity of the mixing container and equal to or smaller than ⅕ of the internal capacity of the mixing container.

3. The method of supplying a mixed gas according to claim 1 , wherein an equivalent circle diameter of a cross-section of an internal space of the replenishment container defined by equation (1):
S=πD 2 /4  (1)

where D is the equivalent circle diameter (mm), S is a sectional area of the internal space of the replenishment container (mm 2 ), and π is a ratio of a circumference of a circle to its diameter, is equal to or larger than 1/100 of a height of the internal space of the replenishment container and equal to or smaller than ½ of the height of the internal space of the replenishment container.

4. The method of supplying a mixed gas according to claim 1 , wherein the charging of the first gas comprises charging a predetermined amount of the first gas into a plurality of replenishment containers which are connected in parallel with each other to the mixing container by replenishment lines having replenishment valves, and which are evacuated,
wherein in the charging of the second gas into the replenishment container, the replenishment container is a first one of the replenishment containers and the replenishment valve is a first one of the replenishment valves, and the second gas is charged into the first one of the replenishment containers charged with the first gas and the first one of the replenishment valves is simultaneously opened to cause the first gas in the first one of the replenishment containers to be forced out by the second gas so that the mixing container is replenished with the mixed gas while the mixed gas is being supplied from the mixing container to the use point,
and the charging of the second gas further comprises successively charging the second gas into a second one of the replenishment containers charged with the first gas and simultaneously opening a second one of the replenishment valves to cause the first gas in the second one of the replenishment containers to be forced out by the second gas, whereby the mixing container can be repeatedly replenished with the mixed gas.

5. The method of supplying a mixed gas according to claim 1 , wherein a pressure at which the mixed gas is supplied to the use point is equal to or higher than 0.5 MPa and equal to or lower than 15 MPa in terms of absolute pressure.

6. An apparatus for supplying a mixed gas, comprising:
a mixing container which is charged with a mixed gas prepared by mixing a first gas having a boiling point equal to or higher than 0° C. and equal to or lower than 100° C. and a second gas having a boiling point equal to or lower than −30° C., and from which the mixed gas is supplied to a use point at a pressure equal to or higher than 0.5 MPa and equal to or lower than 15 MPa in terms of absolute pressure; and
means for replenishing the mixing container with the mixed gas when pressure in the mixing container is reduced to a setpoint as a result of supply of the mixed gas from the mixing container to the use point, wherein the means for replenishing the mixing container includes
a replenishment container having an internal capacity equal to or larger than 1/100 of an internal capacity of the mixing container and equal to or smaller than ⅕ of the internal capacity of the mixing container, and an equivalent circle diameter of a cross-section of an internal space of the replenishment container being defined by equation (1):
S=πD 2 /4  (1)

where D is the equivalent circle diameter (mm), S is a sectional area of the internal space of the replenishment container (mm 2 ), and π is a ratio of a circumference of a circle to its diameter, is equal to or larger than 1/100 of a height of the internal space of the replenishment container and equal to or smaller than ½ of the height of the internal space of the replenishment container,
a replenishment line which connects the replenishment container and the mixing container to each other, the replenishment line having a replenishment valve,
a first container containing the first gas, the first container being connected to the replenishment container by a first gas line having a first gas valve and being charged with a predetermined amount of the first gas when the replenishment container is evacuated and the first gas valve is opened,
a second container containing the second gas, the second container being connected to the replenishment container by a second gas line having a second gas valve, and
a vacuum pump connected to the replenishment container by a discharge line having a discharge valve,
and detection means for detecting the pressure in the mixing container and for opening the second gas valve to charge the second gas into the replenishment container charged with the first gas when the pressure detected by the detection means is reduced to the setpoint as a result of supply of the mixed gas to the use point, and for simultaneously opening the replenishment valve to cause the first gas in the replenishment container to be forced out by the second gas, whereby the mixing container is replenished with the mixed gas.

7. The apparatus for supplying a mixed gas according to claim 6 , wherein an apparatus which performs a surface processing process or a cleaning process is arranged at the use point.

8. The method of supplying a mixed gas according to claim 1 , further comprising performing a surface processing process or a cleaning process at the use point.

Assignees

• Iwatani Corp
• Central Glass Co Ltd

Inventors

• Koike Kunihiko
• Yoshino Yu
• Makihira Naohisa
• Senoo Takehiko
• Aida Toshihiro
• BIRO Tomoya
• Ichimaru Hiroshi
• Tainaka Masahiro

Classifications

• B01F15/00162

  Operations & Transport · mapped topic

• B01F5/10 Primary

  Operations & Transport · mapped topic

• G05D11/001 Primary

  with discontinuous action · CPC title

• B01F15/005

  Operations & Transport · mapped topic

• Y10T137/8766

  With selectively operated flow control means · CPC title