Patent ID: 6224252
Filing Date: 2001-05-01
Classification: B01F

Abstract:
An apparatus for blending high purity chemicals to produce a high purity chemical mixture with circulation, purification and sensing of said chemical mixture between a blending vessel and a chemical mixture storage vessel, comprising:a) a blending vessel having a first inlet for receiving a first high purity chemical, a second inlet for receiving a second high purity chemical and a first outlet for dispensing a high purity chemical mixture of said first and second high purity chemicals;b) a first source of said first high purity chemical connected to said first inlet of said blending vessel, said first source having a first valve to control the introduction of said first high purity chemical from said first source to said blending vessel;c) a second source of a second high purity chemical connected to said second inlet of said blending vessel, said second source having a second valve to control the introduction of said second high purity chemical from said second source to said blending vessel;d) a chemical mixture storage vessel having a third inlet for receiving said chemical mixture from said blending vessel, a second outlet for dispensing said chemical mixture to a point of use and a third outlet for recycling said chemical mixture;e) a delivery line connected to said first outlet of said blending vessel and said third inlet of said chemical mixture storage vessel, a means to purify said chemical mixture passing from said blending vessel to said chemical mixture storage vessel through said delivery line and means for sensing the composition of said chemical mixture in said delivery line downstream of said means to purity;f) a recycle line connected to said third outlet of said chemical mixture storage vessel and connected to said delivery line between said blending vessel and said means to purify said chemical mixture to recycle said chemical mixture from said chemical mixture storage vessel to said delivery line for further passage through said means to purify and said means for sensing and having pumping means to recycle said chemical mixture through said recycle line; andg) an automatic control means connected to said means for sensing and connected to said first valve and said second valve, containing means capable of receiving a signal from said means for sensing representative of the sensed composition of said high purity chemical mixture, comparing it to a predetermined composition value for said high purity chemical mixture and if said sensed composition does not match said predetermined composition value, initiating a signal to said first valve and/or said second valve to adjust the flow of said first high purity chemical and/or said second high purity chemical through said first valve and/or said second valve to return said sensed composition to said predetermined composition value.