Patent Application
20080104991
Not Applicable.
Not Applicable.
Not Applicable.
This invention relates to evaporators that are utilized in making ice cubes.
Ice machines for ice cube producing are known to utilize ice cube forming trays wherein a grid of ice cube forming compartments is cooled by a back plate having an evaporator coil either attached to the back plate or formed as an integral part of the back plate. In some typical applications, a copper tube evaporator is brazed to a copper back plate and then the entire tray is nickel-plated. The tray is installed in a vertical orientation so that water flows down the front in a waterfall effect with the water freezing in the compartments as it flows through them. A defrost cycle releases the frozen ice cubes from the compartments, which may have a slight angle, such as 15° from perpendicular to vertical, so that the ice cubes slide out of the compartments under the force of gravity. While such constructions may be suitable for their intended purpose, there is always room for improvement.
In accordance with one feature of the invention, an ice cube tray evaporator includes a grid of ice cube forming compartments, with each compartment defined by a back wall and four side walls, and two of the side walls defined by microchannel tube legs spaced opposite from each other.
As one feature, the back wall of each compartment is defined by a microchannel tube.
In accordance with one feature of the invention, an ice cube tray evaporator includes a back plate; and a grid of ice cube forming compartments on the back plate. Each compartment is defined by the back plate and four side walls, with two of the side walls being defined by microchannel tube legs spaced opposite from each other.
In one feature, the ice cube tray evaporator further includes a pair of parallel, spaced headers and a plurality of parallel, spaced microchannel tubes extending between the headers with ends of the tubes received in the headers for the transfer of refrigerant between the tubes and the headers. Each of the tubes defines one of the microchannel tube legs. According to a further feature, each of the headers extends along a longitudinal axis and includes a plurality of spaced, elongate tube receiving slots, with each slot receiving an end of the microchannel tubes. The slots are formed at a non-perpendicular angle with the longitudinal axis of the header, and the side walls share the non-perpendicular angle to allow for gravity assisted ejection of the cubes from the compartments with the longitudinal axis extending in a vertical direction.
According to one feature, the ice cube tray evaporator further includes a microchannel tube extending in a serpentine shape to define the microchannel tube legs of the grid. As a further feature, the ice cube tray evaporator further includes an inlet manifold connected to one end of the microchannel tube to deliver refrigerant thereto, and an outlet manifold connected to the other end of the microchannel tube to receive refrigerant therefrom.
In accordance with one feature, the other two side walls of each compartment are defined by elongate strips of heat conductive material.
As one feature, the microchannel tube legs and the back wall are made of aluminum material. As a further feature, the microchannel tube legs and the back wall are plated with nickel.
In one feature, the microchannel tube legs are brazed to the back wall.
According to one feature, the grid is a first grid of ice cube forming compartments, and the ice cube tray evaporator further includes a second grid of ice cube forming compartments, with the first and second grids facing in opposite directions in a back-to-back configuration.
In accordance with one feature, the back plate is a microchannel tube.
As one feature, the microchannel tube legs are brazed to the back wall.
In accordance with one feature of the invention, a method is provided for making an ice cube tray evaporator. The method includes the step of brazing a plurality of spaced, microchannel tube legs to a back plate to form a grid of ice cube forming compartments having the tube legs as side wall.
In one feature, the brazing step is an aluminum brazing step.
According to one feature, the brazing step includes brazing a pair of elongate, parallel spaced headers to ends of each of the tube legs.
As one feature, the method further includes the step of forming an elongate microchannel tube into a serpentine configuration to define the tube legs of the grid prior to the step of brazing.
In accordance with one feature, the method further includes the step of nickel plating the tube legs and back plate after the step of brazing.
Additional objects and/or features of the invention can best be understood by a detailed reading of the entire specification, including the appended claims and drawings.
With reference to
In the embodiment of
It should be understood that in each of the embodiments of
As another option for the embodiments of
While any suitable materials can be used for the components of the above-described ice cube tray evaporators 10, aluminum is a preferred material, with all of the joints being braze joints that are formed in a single oven braze operation. In this regard, it may be desirable for some or all of the components, such as the headers, tube legs, or strips, to be formed of an aluminum braze clad material to assist in the brazing. It is preferred that the microchannel tube legs 28 be brazed to the back plate 12, and the same holds true for the strips 30. After brazing, the ice cube tray evaporator 10 can be nickel-plated to meet FDA regulations for pottable water and ice making.
It should be appreciated that the disclosed ice cube tray evaporators 10 can provide a construction that is relatively easy to manufacture, and when made from aluminum, a construction that can easily have a lower cost than current technology ice cube tray evaporators made from copper. Additionally, it should also be appreciated that the use of microchannel tubes can allow for the ice cube tray evaporator 10 to be used with higher pressure systems such as CO2 systems, as well as with more conventional lower pressure systems, thereby allowing the ice cube tray evaporators 10 to be used with a larger variety of refrigerants in comparison to conventional constructions. It should also be appreciated that the use of microchannel tubes can also reduce the internal volume of the ice cube tray evaporators 10 in comparison to current technology ice cube tray evaporators, thereby reducing the cost of refrigerant to fill the system and some potential risk associated with flammable refrigerants. Also, the use of microchannel tubes can provide quicker cycle times, which include freezing of water in a shortened defrost cycle to remove the ice cubes, in comparison to conventional ice cube tray evaporators.
