Patent Application
20080276629
1. Field of the Invention
The present invention relates to a method and apparatus for producing salt water-mixed sherbet ice, in which ice generated by cooling so-called salt water such as sea water supplied is scraped as small particles of ice by a scraper to thereby produce salt water-mixed sherbet ice having the small particles of ice mixed with the salt water.
2. Description of the Background Art
Sea fishes were heretofore generally cooled with blocks of ice to keep freshness of the sea fishes. However, the sea fishes might be damaged by the blocks of ice because of vibration during marine and land transportation when the blocks of ice were ordinary blocks of ice or the freshness of the sea fishes might be lost by water generated by melting the blocks of ice. Therefore, in recent years, a method in which ice generated by cooling salt water is formed into sherbet-shaped or power snow-shaped ice mixed with salt water (hereinafter referred to as salt water-mixed sherbet ice) by a scraper (also called scraping machine or scraping blade) so that sea fishes are cooled with the salt water-mixed sherbet ice, has been used as disclosed in Patent Document 1.
It has been recently found that the temperature of salt water-mixed sherbet ice for keeping the freshness and taste of sea fishes varies according to the kind of fish when the sea fishes are cooled with the salt water-mixed sherbet ice. For example, when sea fishes are cooled with salt water-mixed sherbet ice at −3° C., there is a possibility that a bad influence such as freezing of fish meat or clouding of fish eyes may occur according to the kind and size of fish.
For example, when salt water-mixed sherbet ice with an ice concentration (percent by weight of small particles of ice to the salt water-mixed sherbet ice, also called ice packing factor (IPF)) of 30% is produced from general sea water (with a salt concentration of about 3.5%), the temperature of the salt water-mixed sherbet ice is −3.1° C. When the salt water-mixed sherbet ice at this temperature is used for cooling fishes, fish meat of almost fishes is however frozen so that the commercial value thereof is lost. It is therefore necessary to adjust the salt concentration in order to provide salt water-mixed sherbet ice at such a temperature that fish meat is not frozen. For example, it is necessary to prepare salt water at a salt concentration of 1.7% in order to produce salt water-mixed sherbet ice with an ice concentration of 30% at −1.5° C. (Refer to Patent Document 1 for the relation between the salt concentration and the temperature of salt water-mixed sherbet ice, though there is no description about the relation between the ice concentration and the temperature of salt water-mixed sherbet ice.)
When salt water with a low salt concentration, for example, a salt concentration of about 1.5% is used, ice produced by an ice-maker becomes so hard that there arises a problem that a scraper of the ice-maker is worn severely and motive power for driving the scraper becomes very large. Therefore, an attempt to use ocean deep water (sea water 200 m or more below sea level) for performing supercooling and canceling of supercooling has been made (see Patent Document 2).
[Patent Document 1] JP-A-2002-115945 (FIG. 1 and paragraph number 0035)
[Patent Document 2] JP-A-2006-10129 (FIGS. 1 to 3 and description thereof)
If sea water with a low salt concentration (e.g. of 1.5%) is used for producing salt water-mixed sherbet ice at a relatively high temperature (e.g. of −1.5° C.) as in Patent Document 1, there arises a problem that the scraper of the ice-maker is worn severely and motive power for driving the scraper becomes very large. It is therefore preferable that salt water-mixed sherbet ice at a relatively high temperature (e.g. of −1.5° C.) can be produced without use of sea water having a low salt concentration.
Although Patent Document 2 has described that ocean deep water (sea water 200 m or more below sea level) is used for performing supercooling and canceling of supercooling, it is difficult to produce salt water-mixed sherbet ice stably by such a method for performing supercooling and canceling of supercooling. It is therefore preferable that salt water-mixed sherbet ice at a relatively high temperature (e.g. of −1.5° C.) can be produced without use of such a method and with use of unexceptional sea water or easily available salt water.
In consideration of the aforementioned circumstances, an object of the present invention is to provide a method and apparatus for producing salt water-mixed sherbet ice at a relatively high temperature (e.g. of −1.5° C.) easily.
The present invention provides a method of producing salt water-mixed sherbet ice, including the steps of: generating salt water-mixed sherbet ice by cooling salt water fed to an ice-maker to generate ice, scraping the ice by scrapers to form small particles of ice to thereby mix the small particles of ice with the salt water; feeding the salt water-mixed sherbet ice from the ice-maker into an ice storage tank to thereby store the salt water-mixed sherbet ice in the ice storage tank; and storing a predetermined amount of the salt water-mixed sherbet ice with a predetermined sherbet concentration at a predetermined low temperature in the ice storage tank while the salt water-mixed sherbet ice stored in the ice storage tank is refluxed from the ice storage tank to the ice-maker repeatedly a plurality of times; wherein water is injected into the salt water-mixed sherbet ice in the process of producing salt water-mixed sherbet ice. Accordingly, there is an effect that salt water-mixed sherbet ice at a relatively high temperature can be produced easily.
This invention also provides an apparatus of producing salt water-mixed sherbet ice, including: an ice-maker which generates salt water-mixed sherbet ice under control based on a controller in such a manner that ice generated by cooling salt water fed to the ice-maker is scraped by scrapers to form small particles of ice to thereby mix the small particles of ice with the salt water; an ice storage tank which stores the salt water-mixed sherbet ice fed from the ice-maker under control based on the controller; and a water injecting unit which injects water into the salt water-mixed sherbet ice; wherein control is performed by the controller so that the salt water-mixed sherbet ice stored in the ice storage tank is refluxed from the ice storage tank to the ice-maker and the injection of water is performed by the water injecting unit in steps of feeding the salt water-mixed sherbet ice from the ice-maker to the ice storage tank and refluxing the salt water-mixed sherbet ice from the ice storage tank to the ice-maker. Accordingly, there can be achieved a salt water-mixed sherbet ice producing apparatus which can produce salt water-mixed sherbet ice at a relatively high temperature easily.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
Embodiment 1 of this invention will be described below with reference to
In
The ice-maker 1 has: a cooling medium side passage 1a provided with an evaporator function; a salt water side passage 1b; scrapers (also called scraping machines or scraping blades) 1c; an outer cylinder 1d; an inner cylinder 1e; and the rotary cylinder 1f. The cooling medium side passage 1a is formed between the outer cylinder 1d and the inner cylinder 1e so that the cooling medium side passage 1a is shaped like a cylinder. The salt water side passage 1b is formed between the rotary cylinder 1f and the inner cylinder 1e so that the salt water side passage 1b is shaped like a cylinder. The scrapers 1c are attached to an outer circumference of the rotary cylinder 1f at regular intervals both in a circumferential direction and in a direction of extension of a center line so that the scrapers 1c are disposed in the salt water side passage 1b.
The salt water-mixed sherbet ice discharging path switching valve 14a for opening and closing the salt water-mixed sherbet ice discharging path 141 is provided in the salt water-mixed sherbet ice discharging path 141 provided in a side wall of the ice storage tank 14 near the bottom of the ice storage tank 14.
The drain path switching valve 14b for opening and closing the drain path 142 is provided in the drain path 142 provided in the bottom of the ice storage tank 14.
The salt water-mixed sherbet ice storage level sensor 14cLs for detecting the storage level of salt water-mixed sherbet ice 143 in the ice storage tank 14 is provided in the ice storage tank 14.
The controller 100 receives detection outputs of the respective sensors 3, 9, 10Ts, 12Tw, 14cLs and 26cl and controls the respective drive sources 2 and 15, the refrigerator 4, the respective valves 8, 14a, 14b, 19, 21 and 28 and the pump controller 11a to execute the salt water-mixed sherbet ice producing sequence in the salt water-mixed sherbet ice producing method and the salt water-mixed sherbet ice producing apparatus shown in
The setting portion 110 in the controller 100 sets a target point, etc. which will be described later.
A salt water feed unit is formed from the salt water source (not shown), the salt water injection pipe 231 and the cold salt water feed control valve 28. A fresh water feed unit is formed from the fresh water source (not shown), the fresh water injection pipe 241 and the fresh water amount adjusting valve 25.
An overall schematic operation of the salt water-mixed sherbet ice producing method and apparatus will be described below with reference to
When the producing apparatus is powered on so that the controller 100 starts, salt water in the salt water source, for example, with a salt concentration of 2.5%, 3%, 3.5%, etc. selected by a user is injected into the ice storage tank 14 through the cold salt water feed control valve 28 so as to be stored in the ice storage tank 14.
The salt water stored in the ice storage tank 14 is thrown into the salt water side passage 1b of the ice-maker (ice generator) 1 by the circulating pump 11. A cooling medium liquid at about −12° C. fed from the refrigerator 4 flows in the cooling medium side passage 1a of the ice-maker 1.
The salt water having the predetermined salt concentration and the predetermined temperature flows in the salt water side passage 1b of the ice-maker 1 and comes into contact with an inner circumferential surface (heat transmission surface) of the inner cylinder 1e of the ice-maker 1, so that the salt water in contact with the inner circumferential surface of the inner cylinder 1e is cooled with the cooling medium in the cooling medium side passage 1a. In this manner, ice is generated on the inner circumferential surface of the inner cylinder 1e.
The ice generated on the inner circumferential surface of the inner cylinder 1e is scraped by the scrapers (scraping blades) 1c on the outer circumference of the rotary cylinder 1f which are driven to rotate by the ice-maker drive source (rotary cylinder drive motor) 2.
The ice scraped by the scrapers 1c is provided as particles with a size of about 0.1 mm. The ice particles float in the salt water in the salt water side passage 1b of the ice-maker 1 so as to be shaped like sherbet containing salt water. That is, salt water-mixed sherbet ice is generated.
The salt water-mixed sherbet ice generated in the salt water side passage 1b of the ice-maker 1 is extruded from the salt water side passage 1b by the circulating pump 11 so as to be fed into the ice storage tank 14 via the flux path piping 13. Thus, the salt water-mixed sherbet ice is stored in the ice storage tank 14.
The salt water-mixed sherbet ice 143 stored in the ice storage tank 14 is refluxed into the salt water side passage 1b of the ice-maker 1 via the reflux path piping 12 by the circulating pump 11. Thus, ice is generated on the inner circumferential surface of the inner cylinder 1e in the same manner as described above. The ice is scraped by the scrapers 1c, so that salt water-mixed sherbet ice containing a large amount of ice particles is generated in the salt water side passage 1b.
The salt water-mixed sherbet ice containing such an increasing amount of ice particles is further extruded from the salt water side passage 1b by the circulating pump 11 in the same manner as described above. Thus, the salt water-mixed sherbet ice is fed into the ice storage tank 14 via the flux path piping 13, so that the salt water-mixed sherbet ice is stored in the ice storage tank 14.
The flux and reflex cycle including reflux of salt water-mixed sherbet ice from the ice storage tank 14 into the salt water side passage 1b, generation of salt water-mixed sherbet ice containing a large amount of ice particles in the salt water side passage 1b and flux of the salt water-mixed sherbet ice containing a large amount of ice particles from the salt water side passage 1b into the ice storage tank 14 is repeated many times so that a predetermined amount of salt water-mixed sherbet ice 143 with a predetermined sherbet concentration IPF is stored in the ice storage tank 14.
In this manner, since it is impossible to obtain salt water-mixed sherbet ice 143 with a predetermined sherbet concentration when salt water is passed through the ice-maker 1 once, the flux and reflux cycle is repeated many times to thereby gradually generate salt water-mixed sherbet ice 143 with a predetermined sherbet concentration.
For example, to generate 10 tons of salt water-mixed sherbet ice 143 with a predetermined sherbet concentration of 30%, the flux and reflux cycle is repeated for about 10 hours to thereby gradually generate the salt water-mixed sherbet ice 143. Accordingly, since a large amount of ice cannot be generated in the salt water side passage 1b of the ice-maker 1 in a short time, the locked state in which the ice-maker cannot operate (the rotary cylinder 1f cannot rotate) is almost prevented from being caused by aggregation due to solidification of sherbet ice, compared with the method and apparatus according to the background art.
Incidentally, as the flux and reflux cycle is repeated, the sherbet concentration of salt water-mixed sherbet ice increases gradually and the viscosity thereof increases gradually. The gradual increase in the sherbet concentration of salt water-mixed sherbet ice and in the viscosity thereof means that the ice-maker 1 gets close to a state in which the ice-maker 1 is overloaded and to a state in which the ice-maker 1 is locked. Accordingly, although the locked state can be almost prevented in Embodiment 1 of the invention as described above, it is necessary to take measures to prevent the locked state, for example, even when sudden drop in the ambient temperature due to sudden change in the weather, repetition of momentary power failure, etc. occurred, so that a more reliable salt water-mixed sherbet ice producing method and apparatus can be achieved.
When the sherbet concentration of salt water-mixed sherbet ice becomes too high, for example, when the sherbet concentration exceeds 50% and becomes a considerably high value of 60%, 70% or 80%, the viscosity of the salt water-mixed sherbet ice 143 becomes so high that not only does forced circulation of the salt water-mixed sherbet ice into the salt water side passage 1b of the ice-maker 1 by the circulating pump 11 become difficult but also the drive source (rotary cylinder drive motor) 2 of the ice-maker becomes high-loaded and overloaded successively and stops finally. Therefore, when salt water-mixed sherbet ice with a proper sherbet concentration, for example, with a sherbet concentration of 30% has been generated, the controller 100 stops the refrigerator 4 to stop ice-making so that sherbet ice cannot be produced any more. On this occasion, the judgment in the controller 100 as to whether the proper sherbet concentration is obtained is, for example, based on the temperature of salt water-mixed sherbet ice measured by the temperature sensor 10Ts. That is, when the temperature of salt water-mixed sherbet ice reaches a specified temperature, the refrigerator 4 is stopped. In other words, the proper ice concentration IPF is detected based on the temperature of salt water-mixed sherbet ice corresponding to the salt concentration, so that the operation of the refrigerator 4 is stopped in accordance with detection of the proper ice concentration IPF of salt water-mixed sherbet ice.
In this manner, the temperature of salt water-mixed sherbet ice is monitored to control the operation of the refrigerator 4 so that overloading and stopping of the ice-maker 1 can be prevented from being caused by excess of the sherbet concentration.
Incidentally, the specified temperature depends on the salt concentration of sea water. For example, the specified temperature is −3.1° C. for a salt concentration of 3.5%, and −2.1° C. for a salt concentration of 2.5%. −3.1° C. is lower than −2.1° C. The salt concentration of sea water varies according to environment. For example, the salt concentration becomes low just after a heavy rain or near a river estuary. Accordingly, when the salt concentration is lowered, it is necessary to increase the specified temperature in accordance with a value detected by the salt concentration sensor 26cl and stop the refrigerator 4 quickly after the sherbet concentration reaches a proper concentration. However, the theory and practice are not always consistent with each other even when the specified temperature is increased because the salt concentration is lowered. That is, salt water-mixed sherbet ice with a higher sherbet concentration than the theoretically estimated value thereof is generated so that the viscosity of the salt water-mixed sherbet ice becomes high. Accordingly, not only does forced circulation of the salt water-mixed sherbet ice into the salt water side passage 1b of the ice-maker 1 by the circulating pump 11 become difficult, but also the ice-maker drive source (rotary cylinder drive motor) 2 may be stopped because of high load. Moreover, when the sherbet concentration becomes further higher, there is fear that ice in the salt water-mixed sherbet ice in the salt water side passage 1b of the ice-maker 1 may grow up so that the volume of ice increases to thereby break the body of the ice-maker 1.
Therefore, when the load on the drive source 2 increases, the controller 100 controls the pump controller (inverter) 11a automatically, in accordance with the output of the ice-maker load detection sensor (current sensor) 3 detecting the load state of the drive source 2 driving the rotary cylinder 1f of the ice-maker 1, to increase the output of the circulating pump 11, increase the discharging pressure of the circulating pump 11 and forcedly extrude salt water-mixed sherbet ice from the salt water side passage 1b to the flux path piping 13 at the initial stage of solidification of sherbet ice to thereby present the ice-maker 1 from lapsing into the overload state or the locked state. Incidentally, when the load on the ice-maker 1 reaches a predetermined value or higher, the user may be informed of the overload state through a buzzer, voice, etc. so that the output of the circulating pump 11 can be increased manually when the user is informed of the overload state. Although the cost of the apparatus becomes slightly low when such a manual operation is used, there is fear that the timing to increase the output of the circulating pump 11 may be delayed or the increasing amount of the output of the circulating pump 11 may be small. To prevent such a disadvantage, it is preferable that the circulating pump 11 is controlled automatically by the controller 100.
Under the state in which the flux and reflux cycle is repeated many times by the controller 100, the salt water feed control valve 28 is closed by the controller 100. On the other hand, under the state in which the flux and reflux cycle is repeated many times, when the target ice concentration IPF of the salt water-mixed sherbet ice is, for example, 25%, the temperature of a mixture of sherbet ice and salt water in the salt water side passage 1b is normally −1.9° C., for example, for a salt concentration of 2.5%. The temperature reaches about −2.7° C. for a salt concentration of 3.5%.
Therefore, in Embodiment 1 of the invention, in addition to the automatic control of the output of the circulating pump 11 based on the output of the ice-maker load detection sensor 3, the output of the temperature sensor 10Ts is used so that automatic control is performed by the controller in such a manner that ice-making is continued until the ice concentration IPF of the salt water-mixed sherbet ice reaches the target value, for example, until the ice concentration IPF reaches 35% when the target ice concentration IPF is 25%; the fresh water amount adjusting valve 25 is opened to feed fresh water 24 from the fresh water injection pipe 241 into the ice storage tank 14 when the temperature detected by the temperature sensor 10Ts reaches −2.3° C. corresponding to the ice concentration IPF of 35%, for example, when the salt concentration C is 2.5%; and the fresh water amount adjusting valve 25 is closed to stop the feed of fresh water 24 into the ice storage tank 14 when the temperature detected by the temperature sensor 10Ts reaches the target value, for example, −1.5° C. In this manner, salt water-mixed sherbet ice at a relatively high temperature (e.g. of −1.5° C.) can be easily produced from salt water having a high salt concentration.
In the method in which ice generated by cooling salt water is scraped by the scrapers 1c as in the ice-maker 1 in this Embodiment 1, when the salt concentration of the salt water is low, the generated ice cannot be scraped because the generated ice is hard. That is, since it is impossible to scrape ice when salt water having a salt concentration lower than 2.5% is used, it is necessary to use salt water having a salt concentration of 2.5% or higher.
However, when salt water having a salt concentration of 2.5% or higher is used, the temperature at which ice generation starts is −1.5° C., ice is generated as it is, and the temperature at which the ice concentration IPF reaches 30% is −2.1° C. The salt water-mixed sherbet ice at −2.1° C. cannot be applied to cooling of some kind of fish because fish meat may be frozen when the salt water-mixed sherbet ice is applied to cooling of fish.
Therefore, in this Embodiment 1, the output of the temperature sensor 10Ts is used so that automatic control is performed by the controller in such a manner that ice-making is continued until the temperature of the salt water-mixed sherbet ice becomes the target value or higher; the fresh water amount adjusting valve 25 is opened to feed fresh water 24 from the fresh water injection pipe 241 into the ice storage tank 14 when the temperature of the salt water-mixed sherbet ice reaches, for example, −2.3° C.; and the fresh water amount adjusting valve 25 is closed to stop the feed of fresh water 24 into the ice storage tank 14 when the detected temperature of the temperature sensor 10Ts reaches the target value, for example, −1.5° C. In this manner, salt water-mixed sherbet ice at a relatively high temperature (e.g. of −1.5° C.) can be easily produced from salt water having a high salt concentration.
The operation sequence in the controller 100 which is a process of producing salt water-mixed sherbet ice based on ice-making and injection of fresh water will be described below with reference to
In
Then, salt water is injected from the salt water injection pipe 231 into the ice storage tank 14. Further, the salt concentration C of salt water in the ice storage tank 14 is measured by the salt concentration sensor 26cl and the level (water level) of salt water in the ice storage tank 14 is measured by the salt water-mixed sherbet ice storage level sensor 14cLs (step ST202).
Then, the ice-making completion temperature Ts1 is set in the setting portion 110 of the controller 100 (step ST203).
Then, the first and second valves 19 and 21 are opened, the main circulating pump 11 is operated and the ice-maker 1 and the refrigerator 4 are operated to perform ice-making (step ST204).
Then, whether or not the temperature Ts of salt water-mixed sherbet ice which is the output of the temperature sensor 10Ts has reached the ice-making completion temperature Ts1 (the set value of which is, for example, about −2.2° C. when the salt concentration C is 2.5%) is judged based on measurement information of the temperature Ts (step ST205).
When a result of the judgment in the step ST205 shows NO (the temperature Ts has not reached the ice-making completion temperature Ts1), ice-making is continued.
On the other hand, when a result of the judgment in the step ST205 shows YES (the temperature Ts has reached the ice-making completion temperature Ts1), ice-making is stopped (step ST206).
The steps ST201 to ST206 are an operation sequence for settings in a standard ice-making function portion 101 of the controller 100. This operation sequence is the same as the operation sequence in steps of the salt water-mixed sherbet ice producing method according to the background art, except the setting of the finished temperature (target temperature) Ts2 of salt water-mixed sherbet ice. In the steps ST201 to ST206, salt water-mixed sherbet ice at a low temperature is generated.
Then, the fresh water amount adjusting valve 25 is opened so that fresh water 24 is injected from the fresh water injection pipe 241 into the ice storage tank 14 (step ST207).
Then, whether or not the temperature Ts of salt water-mixed sherbet ice which is the output of the temperature sensor 10Ts has reached the finished temperature Ts2 (the set value of which is, for example, −1.5° C. when the salt concentration C is. 2.5%) is judged based on measurement information of the temperature Ts (step S208).
When a result of the judgment in the step ST208 shows NO (the temperature Ts has not reached the finished temperature Ts2), injection of fresh water 24 is continued.
On the other hand, when a result of the judgment in the step ST208 shows YES (the temperature Ts has reached the finished temperature Ts2), the fresh water amount adjusting valve 25 is closed to stop injection of fresh water 24 (step S209).
In the step ST209, salt water-mixed sherbet ice at a relatively high temperature, for example, of −1.5° C. as the target value and with an IPF of 25% is finished. The finished salt water-mixed sherbet ice at a relatively high temperature in the ice storage tank 14 is then discharged from the salt water-mixed sherbet ice discharging path 141 automatically or optionally (step ST210).
The steps ST207 to ST209 are an operation sequence in a fresh water injecting function portion 102 of the controller 100. By the steps ST207 to ST209, salt water-mixed sherbet ice at a required relatively high temperature can be produced easily.
Incidentally, the injection of fresh water is performed while the salt water-mixed sherbet ice in the ice storage tank 14 is stirred by the stirrer 16 so that the temperature and IPF of the salt water-mixed sherbet ice are uniformized in the whole region in the ice storage tank 14.
Thermophysical properties of the salt water-mixed sherbet ice will be described below.
The matter that salt water-mixed sherbet ice at a high temperature can be produced when water is mixed with salt water such as sea water as described above will be described below.
First, the freezing temperature of salt water will be described. A salt water NaCl solution is not frozen at 0° C. which is the freezing point of fresh water, but frozen at a point lower than 0° C. because of the action of freezing point depression.
The cold heat quantity of salt water-mixed sherbet ice is defined as follows.
The cold heat quantity can be expressed in specific enthalpy [kcal/kg] of salt water-mixed sherbet ice as follows:
h=cw×(1−Ipf)×T+ci×Ipf×T−L×Ipf
in which h [kcal/kg] is the specific enthalpy of salt water-mixed sherbet ice, c is specific heat, T is the temperature of salt water-mixed sherbet ice, Ipf is the temperature of ice, and L is latent heat of solidification of water.
In this expression, the subscript w is designated as water and the subscript i is designated as ice.
When salt water is cooled, ice begins to be generated at the freezing point and the temperature decreases little by little while the amount of ice increases. The locus thereof varies according to the initial salt concentration and the state thereof is shown in
For example, when salt water with a salt concentration of 3.5% is cooled from 0° C., it is cooled linearly. When the temperature reaches −2.1° C., salt water begins to be frozen and the temperature thereof decreases while the amount of ice increases. For example, when the ice concentration IPF of salt water-mixed sherbet ice is 30%, the temperature reaches −3.1° C. and the specific enthalpy reaches about −26 kcal/kg.
Next, a state in the case where fresh water is added to the salt water-mixed sherbet ice will be considered. When fresh water at a temperature of 0° C. or higher is added, the temperature of the salt water-mixed sherbet ice increases and the salt concentration of the salt water-mixed sherbet ice decreases because the temperature of the salt water-mixed sherbet ice is 0° C. or lower. Incidentally, a solution of ice mixed with salt water, such as salt water-mixed ice water or sherbet ice, has the property that the salt concentration thereof balances with the freezing point. Accordingly, when fresh water is added to salt water-mixed sherbet ice, part of ice in the salt water-mixed sherbet ice is melted so that the salt concentration of the salt water-mixed sherbet ice further decreases but the temperature of the salt water-mixed sherbet ice decreases. Consequently, the salt concentration of the salt water-mixed sherbet ice balances with the freezing point.
For example, when fresh water is injected into salt water-mixed sherbet ice having an ice concentration of 30% after the salt water-mixed sherbet ice is cooled to the ice concentration of 30% while produced with use of salt water having an initial salt concentration of 3.5%, the temperature of the salt water-mixed sherbet ice increases through the locus as shown in
Incidentally,
Because the ice-maker 1 in Embodiment 1 can generate ice only when the initial salt concentration is 2.5% or higher as described above, a 2.5% line as a reference is shown in
Although Embodiment 1 has been described upon the case where fresh water is injected so as to be mixed with salt water having a high salt concentration such as sea water, the aforementioned properties hold even when the fresh water is replaced with salt water. Even when thin salt water (salt water having a low salt concentration) is injected so as to be mixed with salt water having a high salt concentration such as sea water, it is possible to increase the temperature of salt water-mixed sherbet ice. However, the highest effect for increasing the temperature of salt water-mixed sherbet ice can be obtained when salt water having a salt concentration of 0, that is, fresh water is used.
In Embodiment 1, the drive source (rotary cylinder drive motor) 2 of the ice-maker 1 and the main circulating pump 11 can use a low-speed operating system or a variable-speed operating system in accordance with necessity.
Embodiment 2 of this invention will be described below with reference to
Embodiment 2 is configured so that a dewatering process is added to the aforementioned Embodiment 1. Salt water-mixed sherbet ice having an ice concentration IPF higher than that in Embodiment 1 can be produced in Embodiment 2.
That is, as shown in
Incidentally, the steps ST701 to ST705 are executed by a dewatering function portion 103 of the controller 100.
According to Embodiment 2, it is found that salt water-mixed sherbet ice at a relatively high temperature of −1.5° C. with an ice concentration IPF of 30% which is higher than the ice concentration IPF of 25% in Embodiment 1 can be produced as follows. As represented by the arrow in
Embodiment 3 of this invention will be described below with reference to
Embodiment 3 is configured so that the ice-making and the injection of fresh water in Embodiment 1 are performed alternately and repeatedly. Salt water-mixed sherbet ice having an ice concentration IPF higher than that in Embodiment 1 can be produced in Embodiment 3 similarly to Embodiment 2.
In Embodiment 3, as shown in
According to Embodiment 3, it is found that salt water-mixed sherbet ice having an ice concentration IPF higher than that in Embodiment 1 can be produced like Embodiment 2 in the following manner. As represented by the arrow in FIG. 10, ice-making and injection of fresh water are performed alternately and repeatedly several times.
Incidentally, in the case where salt water having a salt concentration of 3.0% is used by way of example, as shown in
By one fresh water injecting cycle, the temperature and IPF of salt water-mixed sherbet ice can be adjusted in a region surrounded by E-C-F. By two fresh water injecting cycles and one ice-remaking cycle, the temperature and IPF of salt water-mixed sherbet ice can be adjusted in a region surrounded by G-C-D-H. By a plurality of fresh water injecting cycles and ice-remaking cycles, the temperature and IPF of salt water-mixed sherbet ice can be adjusted in a region surrounded by K-B-C-D-M.
The region surrounded by A-K-M is a region in which dewatering is essential. Unless the dewatering process in Embodiment 2 is provided, the temperature and IPF of salt water-mixed sherbet ice cannot be adjusted in the region surrounded by A-K-M.
As shown in
By one fresh water injecting cycle, the temperature and IPF of salt water-mixed sherbet ice can be adjusted in a region surrounded by E-C-F. By one dewatering and fresh water injecting cycle, the temperature and IPF of salt water-mixed sherbet ice can be adjusted in a region surrounded by A-B-C-D.
Incidentally, the term “salt water” used in Embodiments 1 to 3 means so-called salt water such as salt water obtained by mixing salt and water or sea water.
Although Embodiments 1 to 3 have been described upon the case where the injection of fresh water and dewatering are controlled by the controller 100 used commonly, the injection of fresh water and dewatering may be controlled by another controller provided separately from the controller 100. In this case, the controller can be easily added to the existing salt water-mixed sherbet ice producing apparatus.
In
Various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention, and it should be understood that this is not limited to the illustrative embodiments set forth herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2007-126908 | May 2007 | JP | national |
