Liquid inert gas dispenser and control
AssigneeContinental Can Company, Inc.
InventorGary G. Hayward
Life of this patent
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Abstract
A control system for providing a closed loop control circuit between a liquid nitrogen dispenser and apparatus for determining internal pressure within a closed can having liquid nitrogen applied thereto whereby the automatic controlling of the volume of liquid nitrogen dispensed into each can is effected. Control data from a pressure test unit is averaged and the average is compared to a preselected set point and converted into a pulse of a width varying in accordance with the average detected pressure of previously filled cans to control the time of dispensing and thus the volume of dispensed liquid nitrogen.
Claims17
A control system for use between a container internal pressure detector and pressure indicator and a liquid inert gas dispenser and for controlling the amount of liquid inert gas dispensed upon each actuation of said dispenser, said pressure detector and pressure indicator being of the type which provides distinct signals in accordance with the existence in a container internal pressures of preselected magnitude and said inert gas dispenser including valve means for varying the quantity of inert gas dispensed in accordance with the time duration of valve opening;
- said control system comprising means for coupling to said pressure detector and pressure indicator for serially receiving each distinct signal resulting from a testing of a container to determine the magnitude of pressure internally of containers, averaging means for averaging data indicated by said signals, comparator means for comparing said averaged data with a preset norm, and converter means connected to said comparator means for controlling the timing of said valve means opening to vary the time of actuation of said valve means in accordance with said averaged data.
A method of controlling the delivery of an inert gas under pressure into a container which is thereafter sealed and has an internal pressure, said method comprising the steps of providing a tank having therein an inert gas in liquid state with there being a discharge opening in a bottom wall of the tank controlled by valve means having an electromechanical actuator, utilizing the valve means to controllably dispense the liquid inert gas into open filled containers passing beneath the tank, closing the containers in sealed relation, testing the closed containers in sequence to determine the internal pressure of each container, taking pressure indicating results and averaging them, comparing the averaged presssure with a preselected standard, and utilizing the results of the comparison to control the length of time of opening of the valve means to thereby control the volume of the liquid inert gas dispensed into each container.
A liquid inert gas dispenser comprising a tank for receiving an inert gas in liquid form, said tank having a flat bottom wall of uniform thickness, a dispensing opening formed entirely in and passing through said bottom wall, said dispensing opening including a passage defined by a valve seat formed by part of said bottom wall, a vertical plunger having at a lower end thereof a valve element normally seated on said valve seat in sealed relation, and an electromechanical actuator for said valve element, said tank having filler means for introducing an inert gas in liquid form thereinto and for maintaining said liquid inert gas at a preselected level with there being a head space above the liquid level for gases, and gas distributing means connected to said head space for receiving and distributing gaseous vapors to open areas outside said tank to prevent icing, said open areas including a space below said tank bottom wall defined by a depending skirt, said gas distributing means distributing gas from an inside wall of said skirt.
Dependencies are inferred from the claim text.