Chemical mix and delivery systems and methods thereof

Abstract

Chemical delivery systems and methods for delivery of liquid chemicals are disclosed. In on embodiment, systems having multi-reservoir load cell assemblies (Figs. 2, 4, 5, 7, 9, 11) for delivering chemicals used in the semiconductor industry are disclosed. In another embodiment (Fig. 12), the present invention provides a multi reservoir load cell assembly (69, 92, 71), including a controller (PLC), a buffer reservoir (92, 71), a main reservoir (69), one or more load cells (12, 13, 67, 68, 91, 96) coupled to the assembly and to the controller, operable to weigh the liquid in the reservoirs, a plurality of supply lines (A-D), each supply reservoir, and a gas and vacuum sources for withdrawing the liquid from the assembly when demanded by the controller and for refilling the assembly from the supply containers. A proportional valve block including a buffer control Intel (80) and outlet (81) valves adjust the pressure to the buffer reservoirs.

Description

[0001] This application is a continuation-in-part of U.S. Application No. 09 / 968,566, filed September 29, 2001, which is now U.S. Patent No. 6,340,098, filed May 30, 2001 Continuation of Application No. 09 / 870,227, U.S. Application No. 09 / 870,227 is a continuation of U.S. Application No. 09 / 568,926, filed February 13, 2001, now U.S. Patent No. 6,269,975, U.S. Application No. 09 / 568,926 is a continuation of now-abandoned U.S. Application No. 09 / 568,926, filed May 10, 2000, which is now a U.S. Patent filed on December 31, 1998 No. 6,098,843 is a divisional application of U.S. Application No. 09 / 224,607, which is a continuation of now-abandoned U.S. Application No. 09 / 222,003 filed December 30, 1998. This application includes by reference each of the above-listed applications and patents. technical field [0002] The present invention generally relates to systems and methods for mixing and / or delivering liquid chemicals, and more particularly to systems and methods for mixing an...

AI Technical Summary

Problems solved by technology

Flow meters are usually only accurate to within 2-3% of the desired flow rate, and are also prone to variation due to input pressure

Second, some chemicals can clog the flowmeter and impede flow through, such as slurry

This method does not yield accurate flow rates due to the potential variability in push gas pressure and the change in flow rate with height in the tank

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