Process for precise volumetrio diluting/mixing of chemicals

• US 5,490,611 A
• Filed: 12/05/1994
• Issued: 02/13/1996
• Est. Priority Date: 09/17/1990
• Status: Expired due to Term

• Current Assignee: Air Liquide Electronics US LP (Air Liquide SA)
• Original Assignee: Applied Chemical Solutions, Inc. (Tokyo Electron Limited)
• Inventors: Bernosky, Eugene W., Ferrie, Edward T. Jr., Roberson, Glenn A. Jr., Geatz, J. Tobin
• Primary Examiner(s): Oberleitner, Robert J.
• Assistant Examiner(s): Bomberg, Kenneth
• Application Number:
  US08/349,429
• Time in Patent Office: 435 Days
• Field of Search: 222/1, 222/43, 222/56, 222/59, 222/61, 222/64, 222/66, 222/71, 222/135, 222/136, 222/145.5, 222/145.6, 222/152, 222/309, 222/318, 222/399, 137/205, 137/208, 137/209, 137/545
• US Class Current: 222/1
• CPC Class Codes: B01F 2101/2204 Mixing chemical components in generals in order to improve chemical treatment or reactions, independently from the specific application
• CPC Class Codes: B01F 35/2217 Volume of at least one component to be mixed
• CPC Class Codes: B01F 35/882 using measuring chambers, e.g. volumetric pumps, for feeding the substances
• CPC Class Codes: B24B 37/04 designed for working plane surfaces
• CPC Class Codes: B67D 7/0272 specially adapted for transferring liquids of high purity
• CPC Class Codes: B67D 7/0277 using negative pressure
• CPC Class Codes: B67D 7/0283 specially adapted for transferring liquids of high purity
• CPC Class Codes: G01F 11/28 with stationary measuring chambers having constant volume during measurement
• CPC Class Codes: G01F 23/00 Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
• CPC Class Codes: G01F 23/02 by gauge glasses or other apparatus involving a window or transparent tube for directly observing the level to be measured or the level of a liquid column in free communication with the main body of the liquid
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring
• CPC Class Codes: H01L 21/67276 Production flow monitoring, e.g. for increasing throughput program-control systems per se G05B19/00, e.g. total factory control G05B19/418

Abstract

Apparatus and method for accurate measuring and mixing of chemicals is disclosed. The apparatus includes one or more metered vessels having a container of predetermined volume and at least one constricted vent tube therein. By mounting a sensor on the constricted vent tube, a greatly amplified measurement of the precise chemical volume in the metered vessel is provided. The apparatus and method of the present invention readily lends itself to a variety of applications and can be adapted to handle virtually any form of chemical mixing, diluting, or generating process.

Claims

1. A process for precision mixing of chemicals from multiple bulk sources which comprises:

providing a metered vessel, such vessel comprising a container of predetermined volume;

providing a first intake conduit for the flow of chemical between a first bulk source and the metered vessel;

providing a first constricted fill tube in the container, the first fill tube extending to a first height;

providing a second intake conduit for the flow of chemical between a second bulk source and the metered vessel;

providing a second constricted fill tube in the container, the second fill tube extending to a second height which is higher than the first height;

providing at least first and second sensors associated with each fill tube, the first sensor detecting when the chemical level is approaching a desired volume and the second sensor positioned to detect the presence of chemical in the associated fill tube when chemical has reached the desired volume in the metered vessel;

providing a first valve on the first intake conduit responsive to the second sensor associated with the first fill tube, for ceasing fluid flow to the metered vessel through the first intake conduit;

providing a second valve on the second intake conduit responsive to the second sensor associated with the second fill tube, for ceasing fluid flow to the metered vessel through the second intake conduit;

providing a conduit from the metered vessel to at least one down-stream facility;

providing means to transfer chemical from the bulk sources to the metered vessel;

providing means to motivate chemical from the metered vessel to the down-stream facility; and

wherein precision mixing is accomplished by the following steps;

motivating chemical from the first bulk source into the metered vessel until chemical reaches the second sensor associated with the first fill tube, at which point the first valve on the first intake conduit is regulated to cease chemical flow to the metered vessel;

motivating chemical from the second bulk source into the metered vessel until chemical reaches the second sensor associated with the second fill tube, at which point the second valve on the second intake conduit is regulated to cease chemical flow into the metered vessel;

mixing together the chemicals from the first bulk source and the second bulk source in measured proportions provided from the metered vessel; and

transferring mixed chemical to the down-stream facility.

2. The process of claim 1 wherein mixing of the chemicals occurs in the metered vessel.

3. The process of claim 1 further comprising

providing a mixing vessel downstream of the metered vessel;

and

wherein mixing of the chemicals occurs in the mixing vessel.

4. The process of claim 3 further comprising

proving multiple metered vessels, each corresponding to one of the bulk sources;

and

transferring chemical from each of the metered vessels into the mixing vessel where mixing occurs.

5. The process of claim 3 which further comprises

providing means to regulate temperature in the mixing vessel;

and

wherein the temperature of the chemical is maintained at a pre-determined level during the mixing step in the mixing vessel.

6. The process of claim 1 further comprising

providing adjustable valve means on each of the first and second intake conduits to permit constriction of the rate of fluid flow;

and

regulating the adjustable valve means to reduce chemical flow rate once the first sensor associated with the first and second fill tubes detests the fluid level approaching the desired volume, and regulating the valve means to cease chemical flow once chemical has reached the desired volume.

7. The process of claim 1 which further comprises

providing a vacuum system in communication with the metered vessel;

providing a pressure system in communication with the metered vessel;

wherein chemical is drawn into the metered vessel by establishing a negative pressure in the vessel through use of the vacuum system, and chemical is dispensed from the metered vessel by applying pressure to the vessel through use of the pressure system.

8. Apparatus for accurately mixing chemicals from at least two bulk sources which comprises:

a metered vessel comprising a container of predetermined volume.

at 1easer first and second constricted fill tubes in the container, the first fill tube extending to a first height, and the second fill tube extending to a second height which is higher than the first height;

a first intake line providing fluid communication between a first bulk source and the metered vessel;

a second bulk intake line providing fluid communication between a second bulk source and the metered vessel;

a dispense line providing fluid communication between the metered vessel and at least one down-stream facility;

at least first and second sensors associated with each fill tube, the first sensor detecting when chemical level is approaching a desired volume and the second sensor positioned to detect the presence of chemical in the associated fill tube when chemical has reached the desired volume in the metered vessel so as to assure precise cessation of chemical flow at the desired volume;

a first value on the first intake line responsive to the second sensor associated with the first fill tube, for ceasing fluid flow to the metered vessel through the first intake line;

a second valve on the second intake line responsive to the second sensor associated with the second fill tube, for ceasing fluid flow to the metered vessel through the second intake line;

wherein the metered vessel is first filled with chemical from the first bulk source until the second sensor associated with the first fill tube detects the presence of chemical in the first fill tube and the valve on the first intake line is closed to cease fluid flow from the first bulk source; and

the metered vessel is next filled with chemical from the second bulk source until the second sensor associated with the second fill tube detects the presence of chemical in the second fill tube and the valve on the second intake line is closed to cease fluid flow from the second bulk source.

9. The apparatus of claim 8 wherein each of the intake lines includes an adjustable valve means responsive to the first sensor associated with the first and second fill tubes, to constrict flow into the metered vessel, and assuring precise cessation of chemical flow into the metered vessel at the desired volume.

10. The apparatus of claim 8 wherein precision volume adjustment apparatus is provided on the metered vessel to assist in calibrating the exact volume of the vessel.

11. The apparatus of claim 10 wherein the precision volume adjustment apparatus comprises means for mounting the first and second fill tubes in sliding relationship with the container to control the level at which chemical begins to enter the fill tube so as to provide precision volume adjustment of the vessel.

12. The apparatus of claim 8 wherein the first and second fill tubes include a valve thereon to control the flow of fluid from the container.

13. The apparatus of claim 12 wherein the valves on the first and second fill tubes are opened only at an appropriate stage to permit chemical to fill each of the fill tubes in order of height.