Fluid sensing in a drip tray

Abstract

A vacuum packaging appliance that detects the amount of liquid present while evacuating and sealing a container is disclosed. The appliance comprises a lid adapted to define a vacuum chamber when it is moved to a closed position relative to a trough in the base of the device. The trough in the lower portion of the device contains a heat-sealing element used to seal the contents of the bag once the vacuum packaging is complete. Disclosed are several embodiments relating to a liquid sensor molded into the walls of the trough. The liquid sensor comprises two electrodes that may be located on opposite sides of the trough or on the same side of the trough. When liquid is present in the trough, the capacitance and resistance between the electrodes changes, thereby sending a signal to a controller indicative of the amount of liquid within the trough while the container is being evacuated. The exact amount of liquid present is compared to a predetermined level of liquid. A vacuum pump controller may suspend operations if the amount of detected liquid exceeds a predetermined amount. The heat-sealing element is also controlled in accordance with the amount of liquid sensed in the trough. The amount of liquid sensed is also indicated to the operator.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application claims priority to Albritton et al.'s U.S. provisional application No. 60 / 492,046, filed Jul. 31, 2003, and entitled FLUID SENSING IN A DRIP TRAY, the contents of which are incorporated herein by reference. The present application is also related to Albritton et al's U.S. provisional application No. 60 / 491,876, filed Jul. 31, 2003, and entitled HEAT SEALING ELEMENT AND CONTROL OF SAME, the contents of which are incorporated herein by reference.TECHNICAL FIELD [0002] The invention relates to a vacuum packaging appliance for packaging products and more particularly to sensing liquid in a trough of the vacuum packaging appliance while evacuating a container and controlling a vacuum pump and heat sealing elements in accordance with the detected amount of liquid. BACKGROUND OF THE INVENTION [0003] Presently, various appliances and methods are used for the purpose of vacuum sealing plastic bags and containers to protec...

AI Technical Summary

Benefits of technology

[0010] Other embodiments of the present invention include positioning the liquid sensing electrodes on opposite sides of the trough, on the same side of the trough, and on the top of the trough. The liquid sensors are also capable of providing a binary signal indicating the amount of liquid is above a predetermined level or an analog signal indicating the exact amount of liquid detected. The liquid sensing electrodes are molded into the trough walls to avoid direct contact with any liquid in order to avoid corrosion.

[0012] The present invention therefore protects the vacuum packaging appliance and also greatly enhances the heat sealing operations of vacuum packaging appliances based on the detected amount of liquid which minimizes the amount of wasted bag material due to faulty sealing.

Problems solved by technology

Conventional commercial appliances and some consumer appliances are generally expensive to manufacture, complex in construction and / or cumbersome to operate.

Although adaptable for low-volume home use, this type of appliance is cumbersome to use and normally requires a liquid separator or filter to prevent liquids or powders, retained within the bag, from being drawn into a vacuum pump connected to the nozzle.

A substantial problem with these and other prior art vacuum packaging appliances is that liquids evacuated from the bag contents collect in the vacuum chamber and may damage the vacuum pump itself.

The presence of these unwanted liquids also causes failures in the heat sealing operations.

Energy supplied to the heat sealing elements is wasted on burning off these unwanted liquids, therefore the temperature of the inside layer of the bag does not reach the required level for heat sealing to occur.

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