Vent port for a refrigerated cabinet

The vent port employs a pair of mated housing parts that define a space for two flap valves. Each flap valve is formed of an aluminum bracket with an aperture for the passage of air and a silicone flap that closes over the aperture. The flap valves are oriented so that gravity enhances the closing of the flaps. Resistors are mounted on the brackets to heat the brackets at a low wattage. In one embodiment, the flap valves are vertically arranged over each other. In another embodiment, the flap valves are horizontally disposed in criss-crossing relation.

This invention relates to a vent port for a refrigerated cabinet, such as refrigerated coolers and freezers.

As is known, vent ports have been used on large coolers and freezers in order to equalize the atmospheric pressure inside the units. As the air inside a cooler or freezer drops in temperature, the air contracts causing a slight vacuum relative to the air pressure outside of the unit. The vent port permits a controlled amount of outside air to enter the unit as the air contracts; typically, by means of an elastomeric “flap” valve or a spring loaded or weight loaded rigid valve in order to equalize the pressure. This type of valve also permits air to enter as the door to the unit is pulled open making the door easier to open.

Additionally, if two oppositely directed valves are used, the vent port will also permit air to be let out as the door of the cooler or freezer is closed in addition to allowing air in as the door is opened, thus decreasing the operator effort to use the door.

Since these valves are at an interface of the cold inside air and the warmer outside air, moisture condensate often develops at the valve, particularly, if the valve is not tightly closed. This condensate can freeze and the resulting ice prevents operation of the valves. In order to prevent this, a heating means is located on or adjacent to the valves. The type of heater most commonly used is a silicone rubber pad with a very small diameter resistance wire imbedded in the pad.

However, the silicone rubber pads that have been used for heating the valves have a high reject rate and often fail prematurely. Additionally, these pads are usually custom made for the application which makes the pads relatively expensive. Further, the limited shape possibilities of this type of pad prevents the optimal placement where the heat is needed resulting in heat being wasted and higher wattage being used to compensate for this, thus wasting electricity.

Accordingly, it is an object of the invention to provide a vent port for a refrigerated cabinet of economical construction.

It is another object of the invention to provide a vent port for a refrigerated cabinet that is of small compact construction.

It is another object of the invention to provide a vent port that may be efficiently operated.

It is another object of the invention to provide a vent port for a refrigerated cabinet that employs a low wattage heater.

Briefly, the invention provides a vent port for a refrigerated cabinet that utilizes a flap of resilient material for opening and closing of the valve through which the passage, or not, of air may be controlled.

In accordance with the invention, a means is provided in the vent port for heating of the vent port and flap so as to preclude the formation of ice. This means is in the form of a metal bracket that has an aperture for the passage of air from one side of the vent port to the opposite side and a resistor mounted on the bracket for generating and delivering heat into the bracket sufficient to melt ice thereon.

The flap of resilient material is mounted on the bracket over the aperture to close the aperture and to lift from the bracket to open the aperture.

The bracket is mounted in a housing of the vent port and the flap is secured at one end to the bracket for movement between a first position in abutment with the bracket in order to close the aperture and a second position spaced from the aperture in order to allow the passage of air therethrough. The flap is disposed on the bracket for movement under gravity from the open position to the closed position.

The resistor is mounted in a channel that is formed by a lower end of the bracket for generating and delivering heat into the bracket. The resistor is of a type that uses a low wattage, for example, 4 watts at 120 volts, that is sufficient to heat the bracket so that moisture that forms on the bracket about the aperture during use does not freeze and interfere with the operation of the flap.

In one embodiment, the vent port is constructed for placement vertically within a door of a refrigerated cabinet. In this embodiment, the housing is sized to fit within a door jamb of the refrigerated cabinet and is formed of a pair of plastic parts that are secured together in mating relation to define a space therebetween. In addition, a pair of the brackets is mounted in the housing with each bracket having an aperture for the flow of air, one aperture for the flow of air into a cabinet and the other for a flow of air in an opposite direction out of a cabinet. The brackets are disposed in vertical alignment relative to each other with each bracket disposed at an acute angle relative to a vertical plane. Flaps are disposed on the respective brackets for movement under gravity from the open position to the closed position.

In addition, a pair of louvered end covers are secured across the plastic parts of the housing in order to close the space within which the brackets are located. Each end cover is also provided with a peripheral lip to engage against a side of the door jamb to seal the housing of the vent port. Each lip has holes for the passage of screws or the like to allow the end cover to be secured to the door jamb so as to locate the housing within the door jamb.

In another embodiment, the vent port is constructed for placement horizontally within a door of a refrigerated cabinet. In this embodiment, the vent port has a box-shaped housing that defines a chamber and a pair of metal brackets mounted in the housing in side-by-side criss-crossing relation to separate one side of the chamber from an opposite side of the chamber. As above, each bracket has an aperture for a flow of air from one of the sides of the chamber to the other side of the chamber. In addition, the vent port has a pair of flaps, each of which is mounted on a respective bracket in overlying relation to an aperture for movement between a first position in abutment with the bracket to close the aperture to the passage of air from one side of the chamber to the other side of the chamber and a second position spaced from the aperture to allow passage of air therethrough.

Also, this vent port has a pair of resistors, each of which is mounted on a respective bracket for generating and delivering heat into the bracket sufficient to melt ice thereon.

In all embodiments, the vent port is of relatively narrow construction and by mounting on the door jamb, can be conveniently visible for inspection and to facilitate wiring of the vent port resistors.

Referring toFIG. 1, the vent port10is mounted in a door jamb11of a door of a refrigerated cabinet, such as a refrigerated cooler or freezer (not shown).

The vent port10has a housing12that is sized to fit within the door jamb11.

As shown inFIGS. 3 and 8, the housing12is formed of a pair of plastic parts13that are secured together in mating relation to define a space therebetween.

Referring toFIGS. 2 and 3, each housing part13is sized to fit into the door jamb11(seeFIG. 1) and each has a flat wall14of rectangular shape and a pair of oppositely disposed flanges15on the wall to define a channel-shaped cross-section. One flange15carries a pin16for sliding into a bore17in the other flange15in order to mate the parts together.

As illustrated inFIG. 8, the wall14of each housing part13is provided with an enlarged boss18that projects toward the other housing part13and has an aperture19through which a securing means, such as a screw, may be passed for securing the two housing parts13together. In addition, the wall14of each housing part13is provided with two pairs of integral walls20,21(seeFIG. 2) that define a slot therebetween and that project from the wall14approximately 0.188 inch.

Each flange15of the housing part13is provided with a semi-circular recess22for the passage of an electrical line.

Referring toFIG. 1, the vent port10is also provided with a pair of brackets23that are made of a heat conducting metal, such as, aluminum, and that are mounted in the slots between the walls20,21of the housing12in vertical alignment relative to each other, as viewed. Each bracket23is disposed at an acute angle relative to a vertical plane.

Each bracket23is of rectangular construction and is of a width to fit between the respective walls20,21of each housing part13. In addition, each bracket23has an aperture24, for example, of rectangular shape for the passage of air, and a bottom edge that is turned upwardly in order to define a channel25.

The vent port10also has a pair of flaps26, each of which is mounted on a respective bracket23in overlying relation to the aperture24therein for movement between a first position, as shown, in abutment with the bracket23in order to close the aperture24and a second position (not shown) spaced from the aperture24to allow passage of air therethrough.

Each flap26is of a shape compatible with the shape of the aperture24in order to close the aperture24to the flow of air when the flap26is in the closed position. For example, each flap26is of rectangular shape and is secured by a pair of rivets27to an upper section of the respective bracket23. Each flap26is made of silicone rubber and acts as a closure valve over the venting aperture24.

The vent port10also has a pair of resistors28, each of which is mounted in a channel25of a respective bracket23for generating and delivering heat into the bracket23sufficient to melt ice thereon. Each resistor28is of a metallic element type that uses a low wattage, for example 4 watts at 120 volts. This type of resistor is called “flame proof” and/or “sand block” or “cement” in the electronics field. The resistors28are off the shelf items and are widely used in the electronics industry. Each resistor28consists of a rectangular ceramic body into which is placed a wound wire or a metal film resistor element and then sealed shut with a ceramic potting mixture.

The resistors28are mounted in the channels25of the brackets23and heat the brackets23because of the power they dissipate. Thus, the heat is applied more precisely to where the heat is needed and less wattage is required and less heat is wasted.

The lower flap26is mounted on the lower bracket23on the same side as the resistor28and opens to relieve higher pressure inside the cooler as the door is closed. The upper flap26on the upper bracket23is mounted on the side opposite to the resistor28and opens in the opposite direction to relieve a lower pressure as the cooler door is opened and also as the air in the cooler contracts. The arrangement of the flaps is such that gravity assists in keeping the flap valves closed.

In order to assemble the vent port10, the brackets23are first positioned in the slots between the walls20,21of one housing part13. Thereafter, the second housing part13is fitted into place on the first housing part13via the pins16and recesses17while positioning the brackets23in the slots defined by the walls20,21thereon. Next, a screw (not shown) is passed through the aperture19in one of the bosses18into a nut (not shown) received in the boss18of the other housing part to secure the two parts together. Alternatively, a single screw may be threaded into the second part12(not shown).

When the two housing parts13are mated, the recesses22define an aperture, for example of ⅞ inch diameter, at the top and bottom of the vent port10. Either aperture may accept a standard one-half inch electrical conduit or a grommet (not shown). The unused aperture is then plugged with a suitable plug closure29.

The electrical line that is fit into the aperture22passes through the door jamb11in a suitable manner from a power source (not shown) and is connected in the suitable manner to the resistors28in order to deliver electrical energy thereto.

Referring toFIG. 1, a pair of louvered end covers30are fitted into the housing parts13and secured to opposite sides of the door jamb11.

Referring toFIG. 4, each louvered end cover30is of generally rectangular shape and has a plurality of louvers31, for example four, which are vertically disposed relative to each other.

Each end cover30has a peripheral flange34, for example, of a height of 0.329 inches, that projects into and between the housing parts13and a peripheral lip35that abuts against the door jamb11. The lip35is provided with holes36in the four corners to facilitate securement of the end covers30to the door jamb11via screws (not shown).

Referring toFIGS. 5 and 6, wherein like reference characters indicate like parts as above, the vent port10′ is mounted in a door jamb11in a horizontal manner.

The vent port10′ includes a box-shaped housing37, for example, made of molded plastic, that defines a chamber38. As indicated, the housing37extends throughout the thickness of the door jamb11.

Referring toFIG. 6, the housing37has a pair of integral partition walls39disposed in side-by-side criss-crossing relation within the chamber38. As indicated inFIG. 5, each partition wall39, only one of which is shown, has an aperture40for the passage of air from one side of the chamber38to the opposite side.

A metal bracket41is mounted on each partition wall39and has an aperture42aligned with the aperture40in the partition wall39. In order to hold the bracket41firmly in place on the partition wall39, the upper edge of the bracket41is inserted within a notch43in the housing37and a lower end of the bracket41has a bent over tang44that extends through the aperture42and fits against the underside of the partition wall39.

Referring toFIG. 5, a resilient flap45, for example made of rubber, is mounted on each bracket41in overlying relation to the aperture40for movement between a first position in abutment with the bracket41in order to close the aperture42to passage of air from one side of the chamber38to the opposite side of the chamber38and a second position (not shown) spaced from the aperture42to allow the passage of air from one side of the chamber38to the other side of the chamber38. The upper end of each flap45is secured by a pair of rivets46to the bracket41via a respective bushing47so that the lower end of the flap45may lift from the bracket41when there is a differential air pressure across the openings40,42and flap45.

In addition, a resistor48is mounted on the bracket41for generating and delivering heat into the bracket41sufficient to melt ice thereon. As illustrated, the bracket41is bent over at the lower end in order to mount the resistor48on the lower end of the bracket41.

Each flap45is disposed for movement under gravity from the open position to the closed position. With the flaps45disposed in criss-crossing relation as indicated inFIG. 6, air may pass through the vent port10′ from opposite sides of the door jamb11.

Referring toFIG. 6, a printed circuit board49is mounted within the housing37within a space between the partition walls39. This circuit board49carries separate circuits for the two resistors48and is electrically connected to the respective resistors48by suitable electrical lines50in order to energize each resistor from a common power cord51(seeFIG. 5). Both circuits are connected to the power cord51via suitable lines52(seeFIG. 6).

A ground wire53is also connected via one of the rivets46to each bracket41. As shown inFIG. 5, each rivet46passes through a terminal end of the ground wire53, a bushing47, a flap45and a bracket41.

Referring toFIGS. 5 and 7, the vent port10′ includes a pair of louvered end covers55, which are mounted on opposite ends of the housing37and secured to opposite sides of the door jamb11, as above described.

Referring toFIGS. 5 and 6, the power cord51passes through the door jamb11and into the housing37to connect with the printed circuit board49.

The power cord51may include a swivel assembly (not shown) that allows the power cord51to be let out through one or the other sides of the housing37.

When in use, should the air within a refrigerated cabinet, for example, to the right hand side ofFIG. 5, become cold thereby creating a partial vacuum, ambient air at a higher pressure on the outside of the cabinet lifts the upper flap45, as viewed inFIG. 6, so that the ambient air may flow into the refrigerated cabinet. Upon closing of the door, pressurized air within the refrigerated cabinet lifts the lower flap45, as viewed inFIG. 6, so that air may escape from the refrigerated cabinet.

The invention thus provides a vent port10of relatively narrow construction that can be mounted on the door jamb11.

The invention also provides a vent port that is able to use resistors of low wattage thereby rendering the vent port efficient and economical in the use of electrical energy.

The invention further provides a vent port that can be easily fabricated, installed in the door of a refrigerated cabinet and maintained in use.