摘要 |
The present invention provides improved method and apparatus for the transfer and delivery of very high purity chemicals for use in semiconductor production and similar processes. By employing a series of vessels arranged in parallel, a vacuum system to draw chemical from one or more bulk sources into the vessels, and a pressure system to deliver chemical under pressure from the vessels, chemicals can be easily delivered from any bulk source to one or more end-users. The use of a vacuum system to draw chemicals through sealed conduits eliminates the need for pumps which are a source of both maintenance problems and contamination in the system. Multiple vessels provide for a variety of flow options, which include continuous and uniform chemical delivery to the end-users, recirculation and regular filtration during periods of low use, and built-in redundancy to avoid system shut down if there is a component failure. Computer controlled process systems provides system flexibility and full automation.
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