초록 ▼

A liquid dispensing method and apparatus in which liquid is dispensed from chambers, that can be pressure vessels, to a flow circuit. A valve network is designed such that when one chamber functions in a dispense mode of operation another chamber functions in a return mode of operation in which unus

A liquid dispensing method and apparatus in which liquid is dispensed from chambers, that can be pressure vessels, to a flow circuit. A valve network is designed such that when one chamber functions in a dispense mode of operation another chamber functions in a return mode of operation in which unused liquid is sent back to such chamber so that liquid is continually circulated. The chamber or vessel undergoing the return mode of operation is vented through a valve that is either a pressure regulation valve having a set point of pressure or a remotely activated control valve response to liquid pressure at the point of use. In such manner internal pressure within the chamber or pressure vessel undergoing the return mode of operation is regulated to in turn regulate liquid pressure at the point of use. In case of pressure vessel operation, gas pressure within each pressure vessel can also be regulated in conjunction with internal pressure during the return mode to in turn regulate liquid pressure at the point of use. As a result of such pressure regulation, constant flow rate of liquid through the flow circuit and at the point or points of use can be assured.

대표청구항 ▼

[ We claim:] [1.] An apparatus for dispensing a liquid to at least one point of use, said apparatus comprising:a plurality of chambers, each having dispense, return and fill modes of operation in which liquid is driven therefrom, unused liquid is returned, and new liquid is introduced, respectively;

[ We claim:] [1.] An apparatus for dispensing a liquid to at least one point of use, said apparatus comprising:a plurality of chambers, each having dispense, return and fill modes of operation in which liquid is driven therefrom, unused liquid is returned, and new liquid is introduced, respectively;a liquid distribution system having a flow circuit connected to said at least one point of use to feed said liquid from said chambers and to return said unused liquid from said at least one point of use, said liquid distribution system also having a valve network communicating between said chambers and said flow circuit;said valve network configured such that two of said chambers can be brought into communication with one another, thereby to allow one of the two of said chambers to function in the dispense mode of operation and the other of the two chambers to function in the return mode of operation, receiving said unused liquid from said at least one point of use; andmeans for driving said liquid from each of said chambers into said liquid distribution system during said dispense mode of operation. [11.] A method of dispensing liquid to at least one point of use comprising:subjecting each of a plurality of chambers to dispense, return and fill modes of operation in a cycle so that when a one of chambers is in the dispense mode of operation, a further of said chambers is in the return modes of operation;driving said liquid from each of said chambers during said dispense mode of operation to said at least one point of use;returning unused liquid back to said further of said chambers undergoing said return mode of operation; andfilling each of said pressure vessels with new liquid to be dispensed during the fill mode of operation. The method of claim 11, wherein each of said chambers are pressure vessels and said pressure vessels are pressurized with gas pressure during the dispense mode to drive the liquid from each of the pressure vessels. The method of claim 12, comprising regulating said gas pressure and internal pressure within each of said pressure vessels during said return mode of operation so that liquid pressure at said at least one point of use remains substantially constant. The method of claim 13, further comprising:sensing the liquid pressure within said flow circuit; andregulating said gas and internal pressures in response to the sensing of the liquid pressure. The method of claim 11, wherein:high, first and second lower levels of said liquid are sensed within each of said chambers, the second lower level being located below the first lower level;when said first lower level of said liquid is sensed within said one chamber, a yet further chamber that has completed said fill mode of operation is also subjected to the dispense mode of operation so that said one and said yet further chamber are simultaneously subjected to said dispense mode of operation;when said second lower level of said liquid is sensed within said one chamber, said one and said further chambers are simultaneously subjected to said return mode of operation;when said first lower level of said liquid is again sensed within said one chamber, due to said one pressure vessel being subjected to the return mode of operation and unused liquid being returned thereto, said further chamber is subjected to said fill mode of operation and is filled with liquid until said high level of said liquid is sensed therein. The method of claim 15, wherein each of said chambers are pressure vessels and said pressure vessels are pressurized with gas pressure during the dispense mode to drive the liquid from each of the pressure vessels. The method of claim 16, comprising regulating said gas pressure and internal pressure within each of said pressure vessels during said return mode of operation so that liquid pressure at said at least one point of use remains substantially constant. The method of claim 17, further comprising:sensing the liquid pressure within said flow circuit; andregulating said gas and internal pressures in response to the sensing of the liquid pressure. The method of claim 18, wherein each of said pressure vessels is pressurized with nitrogen.