US20080178614A1

US20080178614A1 - Ice-making machine with control system

Info

Publication number: US20080178614A1
Application number: US12/012,263
Authority: US
Inventors: John Allen Broadbent
Original assignee: Mile High Equipment LLC
Current assignee: Mile High Equipment LLC
Priority date: 2007-01-31
Filing date: 2008-01-31
Publication date: 2008-07-31

Abstract

An ice-making machine that includes an evaporator and a simple control system, with a single switch, that initiates a harvest cycle by determining a flow rate of water out of the evaporator. The evaporator is a coiled in a flat, space-saving spiral.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The following application is a continuation-in-part of U.S. patent application Ser. No. 12/002155, filed on Dec. 13, 2007, and also claims priority to U.S. Provisional Application Nos. 60/898641, filed on Jan. 31, 2007, 60/918842, filed on Mar. 19, 2007, and 61/007864, filed on Dec. 17, 2007.

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure
The present disclosure relates to ice-making machines. More particularly, the present disclosure relates to ice-making machines having a control system to detect when ice has been formed within the machine, and to initiate the harvest of the ice.
2. Discussion of the Related Art
In the field of ice-making machines, it is desirable to have automated machines that produce continuous supplies of ice, while still maintaining mechanical simplicity and efficient use of resources such as power and water during the ice-making process. The machines of the prior art can require the use of costly and/or complicated control mechanisms that tell the machine when the ice-making cycle is complete, and the ice can be harvested.
Accordingly, there is a need for an ice-making machine that overcomes the aforementioned disadvantages of the machines of the prior art.

SUMMARY OF THE DISCLOSURE

The present disclosure provides an ice-making machine that can comprise a spiral-shaped, flat evaporator tube. In this type of evaporator, ice is formed inside the evaporator tube. The evaporator has one or more water passages and one or more refrigerant passages disposed therein. Water and refrigerant are supplied to the evaporator, and the water is frozen inside the water passages by the conductive effects of the refrigerant while disposed within the evaporator. The ice-making machine of the present disclosure also comprises a water reservoir, a sump and an ice storing bin. Water that passes through the evaporator before it is frozen empties into the reservoir. The machine further comprises a sensor, such as an air pressure sensor, disposed within the reservoir. When the flow rate of water into the reservoir drops below a certain level, the water in the reservoir will drop below a certain level, indicating that the water has frozen within the evaporator. The sensor detects that the water level has dropped below a desired level and closes a switch, which powers a hot gas solenoid valve, which then sends warm refrigerant through the refrigerant passages. This loosens the ice within the evaporator, which is then pushed by water flow through the evaporator into the ice holding bin, where it can be collected by a user.
When the ice in the evaporator has been completely ejected, the water flow through the evaporator and into the reservoir resumes. This reestablished flow raises the level of water in the reservoir. This higher water level is detected by the air pressure sensor which then opens a switch, de-energizing the hot gas solenoid valve and causing the evaporator to cool off and resume freezing water,
The present disclosure thus provides an ice-making machine that comprises an evaporator, wherein the evaporator is wound in a spiral, so that it does not grow substantially in height with each revolution of the evaporator, and a control system comprising a single switch that senses water level in a reservoir located at an outlet of the evaporator.
The present disclosure also provides a method of harvesting ice from an ice-making machine, wherein the ice-making machine comprises an evaporator and a reservoir. The method comprises the steps of: detecting the level of water in the reservoir, wherein water exiting the evaporator is directed into the reservoir, directing a flow of hot gas through the evaporator when the level of water in the first reservoir drops below a first point, ejecting ice from the evaporator, and shutting off the flow of hot gas to the evaporator when the level of water in the reservoir is above a second point.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of an ice-making machine of the present disclosure;

FIG. 2 is a top, perspective view of the ice-making machine of FIG. 1;

FIG. 3 is a partial top view of the ice-making machine of FIG. 1; and

FIG. 4 is a schematic diagram of the control system of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-3, an ice-making machine (“machine”) 10 of the present disclosure is shown. Machine 10 further comprises evaporator 20, which can be covered with an insulating material 21, one or more refrigerant inlet pipes 25, one or more refrigerant outlet pipes 26, water tube 30, reservoir 40 and bin 50. In the embodiment shown in FIGS. 1-3, there are two refrigerant inlet tubes 25 and two refrigerant outlet tubes 26.
The present disclosure provides a control system that can detect when ice forms within evaporator 20, and thus needs to be harvested. As will be discussed in greater detail below, the control system comprises a few very simple and inexpensive components, and thus provides a highly advantageous way of managing the ice-making cycle of the ice-making machine.
During operation of machine 10, water is supplied to evaporator 20 through water tube 30, which is connected to a first end of evaporator 20. For example, water can be supplied through water tube 30 with a pump, as will be discussed in greater detail below. Refrigerant is also supplied to evaporator 20 by refrigerant inlet pipes 25. Refrigerant flows through one or more refrigerant passages, which are disposed within evaporator 20, and water flows through one or more water passages 70, also disposed within evaporator 20. Water flowing through water passage 70 is thus frozen by the refrigerant passing through refrigerant passages 60. The water within water passage 70 freezes at the outer edges of water passage 70 first, and grows toward the middle of water passage 70, until the water is frozen solid. This stops the flow of water through the water passage 70.
While the water within water passage 70 is freezing, the water that passes through water passage 70 exits at an end 22 of evaporator 20, and is collected in reservoir 40. The present disclosure has advantageously developed a control system that can detect when the water within evaporator 20 has frozen, and can send hot gas to evaporator 20, allowing for the ejection of the ice.
Referring to FIG. 4, reservoir 40 has one or more holes disposed therein, that allow the collected water to drain, providing a “leak rate” of the water collected in reservoir 40. While the water is freezing in water passage 70 as described above, water flows constantly into reservoir 40 at a rate that exceeds the “leak rate” of reservoir 40. This causes the level of water to always be at the top of reservoir 40. As the ice grows inside the evaporator 20, the water flow rate coming out of end 22 decreases and eventually stops. When the water flow rate has slowed greatly (or stopped), the “leak rate” of reservoir 40 exceeds the incoming water flow rate, and the water level in reservoir 40 drops.
Water level sensor 45 can be disposed within reservoir 40, to sense the level of the water within reservoir 40. Water level sensor 45 can have a tube 47, which is disposed within reservoir 40. The rising or falling water level in reservoir 40 creates a change in air pressure within tube 47. This change in pressure is communicated through tube 47 to switch 48. Switch 48 senses the air pressure change and opens or closes appropriately to actuate a hot gas valve (not shown). When the water level reaches a desired minimum point, for example, switch 48 actuates to open the hot gas valve, allowing hot gas to flow through refrigerant inlet pipes 25 and into refrigerant passages 60. The hot gas enters the refrigerant passages 60, and loosens the ice formed within water passage 70. The ice will then automatically eject due to the pressure of the water being pumped into evaporator 20 through water tube 30. The ice can be diverted away from falling into reservoir 40 by a grate 43 that directs the ice into bin 50, where it can be collected by a user.
In some cases, it may be advantageous to start the flow of the hot gas before the flow of water into reservoir 40 completely stops, and the point at which switch 48 actuates can be set accordingly. Water level sensor 45 can also be a float switch, which would also send a signal to switch 48 when the water level within first bin 40 drops below a desired level.
Once the ice has been ejected from evaporator 20, water will again begin to flow through end 22 of evaporator 20, and into reservoir 40. The water level within reservoir 40 will rise to the point where it resets water level sensing switch 45, which then turns off the supply of warm refrigerant to refrigerant passages 60. Cold refrigerant then flows again through refrigerant inlet pipe 25 and into refrigerant passages 60. Water level sensing switch 45 is thus a significantly less expensive and simpler way of controlling the making of the ice within machine 10 than is available in the machines of the prior art, which often involve complicated and costly electro-mechanical or electronic controls.
The size and number of the holes within reservoir 40 should be adjusted so that, before water is frozen within water passages 70, the flow rate of water entering reservoir 40 exceeds the leak rate of water exiting reservoir 40. This will ensure that water level sensor 45 closes the hot gas valve as described above. In addition, the holes should be sized so that only a full flow of water out of evaporator 20 will keep reservoir 40 full. At times, the water will start to flow again out of evaporator 20 even when the ice within has not been fully harvested. The holes within reservoir 40 should provide a sufficient leak rate out of reservoir 40 to prevent the reactivation of the freezing cycle when this partial harvest condition occurs.
As also seen in FIG. 4, the present disclosure provides a sump 90, pump 32, and float valve 92. Water draining from reservoir 40 is directed into sump 90. Pump 32 runs continuously, circulating water through evaporator 20. If the water level in sump 90 drops below the desired level, for example after the ice is harvested from evaporator 20, float valve 92 opens to refill sump 90 to the predetermined level. The water used to refill sump 90 can come from an external water source.
Sump 90 also has overflow drain 94 disposed therein. During the ice making cycle when the water flow slows, water empties out of reservoir 40 and into sump 90. This water raises the level of water in the sump 90 and causes water to overflow down drain 94. This regular overflow of water each cycle is needed to prevent excessive concentration of impurities in the ice making water. Excess impurities in the ice making water can lead to cloudy ice and formation and precipitation of lime scale into sump 90.
As is shown in FIGS. 1-3, evaporator 20 is a flat, spiral tube. Evaporator 20 is preferably made of an inexpensive, thermally conductive material that is suitable for contact with water. For example, this material can be thermally conductive plastic, or a metal alloy such as brass. In one embodiment, evaporator 20 is made of an aluminum alloy. Evaporator 20 can also be coated with a corrosion-resistant material, and/or anodized. In addition, evaporator 20 can comprise a variety of orientations of water passages 70 and refrigerant passages 60. For example, evaporator 20 can have one water passage 70, and two refrigerant passages 60, or two water passages 70 and one refrigerant passage 60.
While the instant disclosure has been described with reference to one or more exemplary or preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope thereof. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiment(s) disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope as described herein.

Claims

1. An ice-making machine comprising:

an evaporator, having a spiral wound shape; and

a control system comprising a sensor to sense a water level in a reservoir, wherein said reservoir is disposed to receive passes through said evaporator.

2. The machine of claim 1, wherein said reservoir comprises holes therethrough for drainage.

3. The machine of claim 1, wherein during a freezing cycle, water flows into said reservoir at a rate that exceeds a drainage rate of the reservoir.

4. The machine of claim 3, wherein when said water level of said reservoir reaches a predetermined minimum, said sensor initiates a harvest cycle of ice disposed within said evaporator.

5. The machine of claim 1, further comprising a sump in fluid communication with said reservoir, such that water flows from said reservoir to said sump, and wherein at least a portion of said water in said sump is recirculated to evaporator.

6. A method of harvesting ice from an ice-making machine, wherein said ice-making machine comprises an evaporator and a reservoir, the method comprising the steps of:

detecting the level of water in said reservoir;

directing a flow of hot gas through said evaporator when said level of water in said first reservoir is equal to or less than a predetermined value; and

terminating said flow of hot gas to said evaporator when said level of water in said reservoir is equal to or greater than a second predetermined value.

7. The method of claim 6, wherein said detecting step comprises a sensor, said sensor comprising a tube disposed within said reservoir, wherein said tube is in communication with an air pressure sensing switch.

8. The method of claim 7, wherein said directing step is performed by opening a refrigerant valve in response to said switch.