Apparatus and method for the transfer and delivery of high purity chemicals

An apparatus for providing chemical transfer and delivery of chemical from a bulk source to an end-use station which comprises

• a lifting vessel;
• a source conduit between the bulk source and the lifting vessel, including a valve to control fluid flow through the source conduit;
• a vacuum system in communication with the lifting vessel and including means to evacuate gas selectively from the lifting vessel;
• a pressure system, operated independently of said vacuum system, in communication with the lifting vessel pressurize selectively the lifting vessel;
• a delivery vessel in communication with the lifting vessel, including a transfer conduit permitting the transfer of chemical from the lifting vessel to the delivery vessel;
• a delivery conduit from the delivery vessel to the end-use station, including a valve to control fluid flow through the delivery conduit;
• a connecting conduits between the lifting vessel, the delivery vessel, and the end use station including valving to regulate flow through such conduits so to allow any vessel to be bypassed in the system without affecting the operation of the wherein said connecting means may include said transfer conduit and said delivery conduit system.

An apparatus for transfer and delivery of chemical from a bulk source to an end-use stationw hich comprises:

• at least one vessel;
• means to produce and control alternating pressures in the vessel between a negative pressure and a positive pressure;
• a source conduit between the bulk source and the vessel;
• a delivery conduit between the vessel and the end-use station;
• a recirculation conduit from the vessel back to the bulk source;
• wherein chemical is transferred between the bulk source and the vessel by producing a substantial negative pressure in the vessel by means of a vacuum pump and drawing the chemical into the vessel through the source conduit;
• chemical is transferred between the vessel and the end-use station by producing a positive pressure in the vessel and forcing the chemical to the end-use station through the delivery conduit;
• and
• chemical is recirculated back to the bulk source during periods of low deamdn at the end use stations by producing a positive pressure in the vessel and forcing chemical to the bulk source through the recirculation conduit.

Apparatus for the transfer and delivery of high purity chemical from a bulk source to an end use station which comprises:

• a source conduit which attaches to the bulk source and communicates chemical to a first vessel;
• a vacuum system in communication with the first vessel which is capable of evacuating gas from the first vessel and producing a negative pressure therein so to cause the chemical to be drawn from the bulk source into the first vessel;
• a pressure system in communication with the first vessel which is capable of producing a positive pressure in the first vessel so to force chemical from the first vessel to a second vessel in communication with the first vessel;
• a pressure system in communication with the second vessel which is capable of producign a positive pressure in the second vessel so to force chemical from the second vessel through a delivery conduit, chemical being supplied to the end use station by way of the delivery conduit;
• and
• wherein means are provided to sense the demand for chemical at the end use station, and means are provided responsive to said sensing means to recirculate chemical from the apparatus back to the bulk source during periods of low demand for chemical.

A process for providing chemical transfer and delivery of chemical from a bulk source to an end-use station which comprises

• providing a lifting vessel;
• providing a source conduit between the bulk source and the lifting vessel, including a valve to control fluid flow through the source conduit;
• providing a vacuum system in communication with the lifting vessel and including means to evacuate gas selectively from the lifting vessel;
• providing a pressure system, operated and controlled independently of said vacuum system, in communication with the lifting vessel and including means to pressurize selectively the lifting vessel;
• providing a delivery vessel in communication with the lifting vessel;
• providing a delivery conduit from the delivery vessel to the end-use station, including a valve to control fluid flow through the delivery conduit;
• providing connecting conduits between the lifting vessel, the delivery vessel, and the end use station including valving to regulate flow through such conduits so to allow any vessel to be bypassed in the system without effecting the operation of the system;
• wherein chemical is transferred from the bulk source to the end-use station by the process comprising
• employing the vacuum system to evacuate the lifting vessel of gas so to create a negative pressure therein;
• opening the valve on the source conduit between the bulk source and the lifting vessel so to cause the chemical to be drawn from the bulk source to the lifting vessel;
• closing the valve on the source conduit and pressurizing the lifting vessel;
• causing the chemical under pressure in the lifting vessel to transfer to the delivery vessel;
• and
• dispensing chemical under pressure from the delivery vessel to the end-use station as needed by controlling a valve on the delivery conduit;
• allowing continuous flow to the end-use station as needed with a constant rate discharge;
• wherein means are provided to recirculate the chemical from the delivery vessel to the bulk source;
• and
• the chemical is recirculated to the bulk source during periods of low demand at the end use stations.