Patent ID: 12220070

DETAILED DESCRIPTION

Described herein is an exemplary preservation system to preserve perishable products in a display case. The display case is typically refrigerated. However, the preservation system may also be used in non-refrigerated applications. Such perishable products may include, for example, produce, meat, seafood, or cheese. The preservation system emits a fine fog that is non-wetting, i.e., a dry fog. The dry fog advantageously holds approximately 75% relative humidity (RH) to 99.9% RH level throughout the display produce case. These levels are excellent for minimizing produce shrink rates. The invention is illustrated and described in connection with an exemplary produce display case. As will be apparent, the configuration of the display case does not form part of the invention.

The dry fog is generated using a set of piezoelectric transducer or ultrasonic atomizer nozzles, such as nebulizers, mounted within the produce case. This piezoelectrical transducer set can emit the dry fog without any water bath reservoir.

Dry fog can be a subjective term as it is dependent on the ambient conditions. To humidify spaces, filtered water is fractionated into various water particles sizes. Conventional misting systems typically have particle sizes of approximately 10 to 90 microns. This is a light mist that results in condensation/water droplets forming on items it contacts. A dry fog is a particle small enough to evaporate in the environment before it hits any surface. These systems operate in very humid conditions, so a dry fog is considered to be particles in the 0.1 to 10 micron range. Particles sizes in this range feel very dry to the hand.

The preservation system may be equipped with an ozone sanitization system to clean throughout the produce case, dry fog equipment, and produce. It does so by providing significant log reductions in bacteria, virus, fungus and mold counts.

Referring initially toFIGS.1-4, a display case, such as a conventional refrigerated produce case10includes a base12connected to a relatively short upstanding front wall14and a taller upstanding rear wall16. A bottom shelf18is disposed between the front wall14and the rear wall16to define a lower produce space20. A shelf22extends forwardly from the rear wall16above the bottom wall18to define an upper storage space24. A top26extends forwardly atop the rear wall16above the shelf22.

The lower storage space20and the upper storage space24are used to store produce or the like, such as fruits and vegetables. The invention comprehends providing for use with a product zone of such a produce case10a preservation system generally designated28adapted to selectively emit a fine, non-wetting dry fog downwardly into the storage spaces20and24.

The preservation system28may be connected to a pressurized water supply via a tube30. The supply may be a conventional municipal water supply. The tube30is connected through a control device such as a control valve32to a pressure regulator34via a tube36, see alsoFIG.2.

A nozzle housing38, see alsoFIG.5, is located on an underside of the case top wall26. A plurality of piezoelectric transducer nebulizers40are mounted in spaced apart relationship in the housing38and emit the dry fog F through openings42. In the illustrated embodiment, the spacing is about one foot. The nebulizers40are fluidically connected in series, using tubes44, to an output of the pressure regulator34. Each of the nebulizers40is electrically connected to a connector board46via cables48. An ozone mist bar50having openings52may also be housed in the nozzle housing.

A control box54is mounted to the top wall26. An ozone generator55may also be mounted on the top wall26. The control box54houses a control system56, seeFIG.6, for controlling the preservation system28. The control system56has a 12Vdc power supply58that is connected to a convention 120Vac source60. The power supply58supplies its output via a block connector62to a timer64, the control valve32, and a nebulizer controller66. The timer64is connected to the control valve32and to the controller66. The controller66is connected to the connector board46.

The pressurized water supply to the tube36is from a water in source68. Typical water pressure tends to range between 45 and 80 psi. The pressure regulator34is set to reduce water pressure to a relatively low range of 0.5-2 psi, and advantageously to about 1-1.5 psi. The tube44from the last of the nebulizers40terminates in a drain70.

The timer64is configured to alternately generate an on signal and an off signal to the control valve32and to the controller66. Particularly, the timer64periodically controls the valve32to supply water to the pressure regulator34and to enable the controller66whereby the nebulizers40emit the dry fog F to maintain desired relative humidity level throughout the display case.

In an exemplary embodiment of the invention, the nebulizers40comprise M05 or M08 spray heads from Tekceleo. The controller66comprises an Electronic Control Unit (ECU) of Tekceleo. The controller66develops a pulse width modulated (PWM) control signal to drive the nebulizers40. Duty cycle of the PWM signal can be user selected. In an exemplary embodiment of the invention, the duty cycle is set to 100%. A lower duty cycle may also be used, as desired. The controller66feeds the correct voltage, current and on-off pulses to cause the piezoelectric transducer in the atomizer nozzles of the nebulizers40to vibrate at the correct frequencies.

The controller66is configured to control the nebulizers40to emit particles in the 0.1 to 10 micron range to maintain desired relative humidity level of about 75% to 99.9% RH throughout the display case10.

The exemplary preservation system can include up to eight nebulizers40. As is apparent, a different quantity may be used, as necessary or desired.

For a produce case application, eight nebulizers40are placed in series in a row in a preservation system28. With this maximum eight nebulizers, the system will operate properly. A nebulizer40will be mounted every lineal foot of case. If there is a need to cover more than eight lineal feet, then additional systems28may be used.

For meat/seafood service case applications, as many nebulizers as required to fill the case with dry fog will be used. If the case requires more than eight nebulizers to fill with fog, then multiple systems28will be used.

For cheese display cases, the number of nozzles may be a function of desired appearance with a rolling fog over the cheese to attract shoppers. The preservation system28will keep cheese fresh if unwrapped. Here again, up to eight nebulizers40maximum will be driven by the water pressure.

The preservation system28may also be used in display cases such as humidors and deli cases. These cases are for perishable products that do not use cold temperature refrigeration equipment.

Thus, there is disclosed herein the preservation system28for emitting a dry fog F to preserve perishable products in a display case10comprising a control device, such as a control valve32, selectively actuated to provide a pressurized water supply68. A pressure regulator34is connected to the control device32for reducing water pressure to a range of 0.5-2 psi. A plurality of piezoelectric transducer atomizer nozzles40are operatively mounted in spaced apart relationship in the display case10and are fluidically connected in series with an output of the pressure regulator34to emit the dry fog in the display case10. The control system56comprises a controller66for controlling a duty cycle of a pulse signal to vibrate the piezoelectric transducers in the plurality of atomizer nozzles40, and a timer64for alternately generating an on signal and an off signal to periodically control the control device32to supply water to the pressure regulator34and to enable the controller66whereby the atomizer nozzles40emit the dry fog to maintain desired relative humidity level throughout the display case10.

It will be appreciated by those skilled in the art that there are many possible modifications to be made to the specific forms of the features and components of the disclosed embodiments while keeping within the spirit of the concepts disclosed herein. Accordingly, no limitations to the specific forms of the embodiments disclosed herein should be read into the claims unless expressly recited in the claims. Although a few embodiments have been described in detail above, other modifications are possible. Other embodiments may be within the scope of the following claims.

The foregoing disclosure of specific embodiments is intended to be illustrative of the broad concepts comprehended by the invention.