Portable icemaker and method for making ice

A method including the steps of:

• (a) applying heat to a driving vessel charged with liquid ammonia and driving gas at atmospheric temperature and at an operating pressure;
• (b) enabling the liquid ammonia and driving gas to expand into an elongated evaporator tube to enable at least a portion of the liquid ammonia to go to a gaseous state;
• (c) transferring heat to a cylindrical outer surface of the evaporator tube and a heat transfer feature on the evaporator tube from a target material within a target material reservoir, the target material reservoir having a cavity therein with a first portion having a size and shape closely corresponding to the cylindrical outer surface of the evaporator tube and having a second portion comprising an elongated slot having a shape closely corresponding to an outer surface of the heat transfer feature, and the target material reservoir being positioned in an operating position in which the evaporator tube extends through the target material reservoir cavity and the heat transfer feature extends into the slot;
• and
• (d) condensing the ammonia gas to a liquid state and returning the resulting liquid ammonia and driving gas to the driving vessel.

An apparatus including:

• (a) an elongated evaporator tube having a generally cylindrical outer surface with a helical ridge formed thereon;
• (b) a driving vessel charged with liquid ammonia and a driving gas at an operating pressure and temperature;
• (c) a heat source adapted to apply sufficient heat to the driving vessel to force liquid ammonia through an evaporator supply line to an expansion chamber inlet associated with the evaporator tube;
• (d) a return system facilitating the return of ammonia from an expansion chamber outlet of the evaporator tube to the driving vessel;
• and
• (e) a target material reservoir having a central opening extending there through, the central opening having a size and shape closely corresponding to the cylindrical outer surface and heat transfer feature of the evaporator, and also having a helical portion corresponding to the helical ridge so as to be threadable over the helical ridge.

An apparatus including:

• (a) an elongated evaporator tube having a generally cylindrical outer surface with a heat transfer feature formed thereon, the heat transfer feature comprising a projection extending from the cylindrical outer surface of the evaporator tube;
• (b) a driving vessel charged with liquid ammonia and a driving gas at an operating pressure and temperature;
• (c) a heat source adapted to apply sufficient heat to the driving vessel to force liquid ammonia through an evaporator supply line to an expansion chamber inlet associated with the evaporator tube;
• (d) a return system facilitating the return of ammonia from an expansion chamber outlet of the evaporator tube to the driving vessel;
• and
• (e) a target material reservoir having a central opening extending there through, the central opening having a size and shape closely corresponding to the cylindrical outer surface of the evaporator tube and having a J-shaped or L-shaped slot formed therein to closely receive the projection extending from the cylindrical outer surface of the evaporator tube.

A method including the steps of:

• (a) applying heat to a driving vessel charged with liquid ammonia and driving gas at atmospheric temperature and at an operating pressure;
• (b) enabling the liquid ammonia and driving gas to expand into an elongated evaporator tube to enable at least a portion of the liquid ammonia to go to a gaseous state;
• (c) transferring heat to the outer surface of the evaporator tube and a heat transfer feature from a target material in a target material reservoir when the target material reservoir is in an operating position with respect to the evaporator tube and heat transfer feature, the heat transfer feature comprising a helical ridge on the evaporator tube;
• (d) condensing the ammonia gas to a liquid state and returning the resulting liquid ammonia and driving gas to the driving vessel;
• and
• (e) threading the evaporator tube and helical ridge into a corresponding helical grooved passage through the target material reservoir to place the target material reservoir in the operating position.

A method including the steps of:

• (a) applying heat to a driving vessel charged with liquid ammonia and driving gas at atmospheric temperature and at an operating pressure;
• (b) enabling the liquid ammonia and driving gas to expand into an elongated evaporator tube to enable at least a portion of the liquid ammonia to go to a gaseous state;
• (c) transferring heat to the outer surface of the evaporator tube and a heat transfer feature on the evaporator tube from a target material within a target material reservoir, the reservoir being in an operating position closely surrounding the evaporator tube and heat transfer feature;
• (d) condensing the ammonia gas to a liquid state and returning the resulting liquid ammonia and driving gas to the driving vessel;
• and
• (e) securing the target material reservoir over the evaporator tube by cooperation between a projection from the evaporator tube and a projection receiving slot in the target material reservoir and wherein the heat transfer feature comprises the projection from the evaporator tube.