JP4960049B2 - Ice concentration meter - Google Patents

Description

  The present invention relates to an ice concentration meter capable of directly measuring the ice concentration of sherbet ice in real time.

In sherbet ice (ice slurry) used to maintain the freshness of seafood or as a heat source for cooling in a district heating and cooling system, the viscosity increases as the ice concentration in the sherbet ice increases, and the sherbet ice passes through the transport pipe. The conveyance efficiency of the conveyance pump during conveyance deteriorates or the conveyance becomes impossible. Therefore, it is necessary to measure the ice concentration in order to keep the ice concentration in the sherbet ice at a predetermined value.
Moreover, since the characteristics of the cooling sherbet ice depend on the ice concentration, it is necessary to accurately grasp the ice concentration. Currently, the ice concentration is calculated by converting the sherbet ice temperature, but it is not accurate.

  As a conventional method for measuring the ice concentration, a predetermined amount of sherbet ice (ice slurry) and a predetermined amount of freezing point depressing liquid are mixed to form a mixed liquid, and the temperature of this mixed liquid having a reduced freezing point is detected and an arithmetic unit And the ice concentration of the sherbet ice is calculated by a calculation device. (See Patent Document 1)

Although the ice concentration is not directly measured, a microcapsule slurry in which a latent heat storage material is enclosed in a microcapsule as a core material and mixed with water to form a slurry, and a known capsule A medium having physical properties (warm water) is placed in a mixer at a predetermined flow rate at a predetermined temperature, and the calorific value of the core material is measured by measuring the slurry temperature after mixing. There is one that measures the specific gravity of the core material by providing a flow meter and simultaneously measuring the mass flow rate. (See Patent Document 2)
JP-A-5-340903 Japanese Patent No. 3327866 ([0064] to [0065], FIG. 6)

  The conventional method shown in Patent Document 1 (a method of calculating the ice concentration of sherbet ice from the temperature of the mixed solution of sherbet ice and freezing point depressant) requires the use of the freezing point depressant as the test solution. To measure the ice concentration by measuring the temperature at which the freezing point is lowered, and after measuring the ice concentration, drain the mixture in the mixing tank and repeat the same measurement again to measure the ice concentration. The ice concentration could not be measured in real time. Furthermore, there is a case where the relationship between the sherbet ice temperature and the ice concentration collapses and the ice concentration becomes abnormally high when ice making and stopping are repeated for a long time with the sherbet ice in the ice storage tank. was there.

  Moreover, the conventional method shown in Patent Document 2 (a method in which slurry and hot water whose mass and temperature are respectively known is put into a mixer, the temperature after mixing is measured, and the calorie and specific gravity of the slurry are calculated from the calorie balance) It is necessary to prepare a medium (warm water) with known physical properties with known mass and temperature separately from the slurry, and after measuring the amount of heat and specific gravity of the slurry, drain the mixed liquid in the mixer and again It was necessary to repeat the same measurement, and it was difficult to measure in real time.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an ice concentration meter that can directly measure the ice concentration of sherbet ice and can measure it in real time. Yes.

The ice concentration meter of the present invention is a heating container for a cylindrical container into which sherbet ice is introduced, a coil-shaped electric heater provided in the heating container for heating and melting the sherbet ice, and supplying electric power to the electric heater. From a power source, a first thermometer for measuring the temperature of the sherbet ice before being introduced into the heating container, a second thermometer for measuring the temperature of the water after melting the sherbet ice derived from the heating container, from the heating container A flowmeter that measures the flow rate of the water after melting the derived sherbet ice. If the temperature measured by the second thermometer is lower than the set temperature, the output value of the power source is increased and measured by the second thermometer. If the temperature is higher than the set temperature by varying the output value of the power supply to lower the output value of the power supply, the output controller to maintain the temperature of the water is derived from heating vessel to a predetermined value, and the first temperature Calculation to measure the ice concentration of sherbet ice by inputting the temperature measured by the second thermometer, the flow rate measured by the flow meter, and the current value flowing from the power source to the electric heater, and calculating them It is equipped with a vessel.

  This invention can measure the ice concentration in real time just by introducing the sherbet ice into the heating container and continuously discharging the melted sherbet ice from the heating container, and nothing is mixed with the sherbet ice. Therefore, the ice concentration can be measured directly, and an accurate ice concentration meter can be obtained.

Embodiment 1 FIG.
A real-time ice concentration meter for sherbet ice according to Embodiment 1 of the present invention will be described below with reference to FIG.
In FIG. 1, an ice storage tank 1 stores sherbet ice 2 manufactured by a seawater sherbet ice manufacturing apparatus or the like, and one end of a sherbet ice pipe 4 is connected to the ice storage tank 1 through a manual valve 3. The other end of 4 is connected to the inlet of the heating vessel 5. A stirring blade 6 and an electric heater 7 are installed in the heating container 5. A discharge pipe 8 is connected to the outlet of the heating container 5, a metering pump 9 and a flow meter 10 are provided in the discharge pipe 8, and the sherbet ice 2 melted by the heating container 5 into water is the discharge pipe 8. Discharged from. A first thermometer 11 is attached to the sherbet ice pipe 4, and a second thermometer 12 is attached to the discharge pipe 8 at the rear stage of the heating container 5. Electric power is supplied from a power source 13 to the electric heater 7 in the heating container 5, and an ammeter 14 is attached between the power source 13 and the electric heater 7. The computing unit 15 inputs each detected value measured by the flow meter 10, the first thermometer 11, the second thermometer 12, and the ammeter 14, calculates the ice concentration, and outputs an ice concentration output value 16. To do.

The operation in the first embodiment will be described.
In FIG. 1, the sherbet ice 2 stored in the ice storage tank 1 is led from the sherbet ice pipe 4 to the heating container 5 through the manual valve 3 by driving the metering pump 9. The electric heater 7 in the heating container 5 is supplied with electric power from the power source 13 to heat the sherbet ice 2 in the heating container 5 and melt the ice content of the sherbet ice 2. Further, the convection of the sherbet ice in the heating container 5 is improved by the stirring blade 6 in the heating container 5 so that the ice melts reliably. The melted sherbet ice 2 is continuously discharged from the discharge pipe 8 through the metering pump 9 and further through the flow meter 10. When the amount of heating is appropriate and the ice melts completely, the sherbet ice temperature observed by the first thermometer 11, the salt water temperature observed by the second thermometer 12, the flow rate and current observed by the flow meter 10 Based on the current value observed by the total 14, the ice concentration of the sherbet ice is calculated by the calculator 15.

Here, the sherbet ice temperature observed by the first thermometer 11 is T1, the salt water temperature observed by the second thermometer 12 is T2, the flow rate observed by the flow meter 10 is V, and the ammeter 14 is observed. Assuming that the current value is I, the ice concentration can be calculated as follows.
Here are the definitions:
Mwo: Mass flow rate of sherbet ice (water + ice) kg / sec
(Determined from the flow rate V observed with the flow meter 10. Mwo = ρw * V)
Cw: Specific heat of water kJ / kg ・ K
Ci: Specific heat of ice kJ / kg · K
ρw: Density of water after melting kg / m ³
Two: Temperature after melting ° C. or K (amount T2 observed with the thermometer 12)
Ts: temperature of sherbet ice ° C. or K (amount T1 observed by the thermometer 11)
L: Ice latent heat kJ / kg
r: Ice concentration (ratio of ice mass in sherbet ice mass) The water concentration is 1-r.

Hereinafter, the energy relationship is expressed with respect to the mass of the sherbet ice passing through the channel cross section in 1 second. First, arrange the energy before melting the sherbet ice.
(1) In sherbet ice, the energy of ice (sensible heat) (that is, the energy held before melting by the amount that contributed to the increase in ice temperature) is the energy of ice (sensible heat) = the mass of ice * the ice Specific heat * temperature of sherbet ice (ie ice temperature)
The mass of ice is r * Mwo, the specific heat of ice is Ci, the temperature of sherbet ice is Ts
However, Mwo = ρw * V
So ice energy (sensible heat) = rMwoCiTs (1)
(2) The energy of water in sorbet ice (energy held before melting as seen from the temperature rise) is water energy = mass of water * specific heat of water * temperature of sorbet ice (ie water temperature)
The mass of water is (1-r) * Mwo, the specific heat of water is Cw, and the temperature of sherbet ice is Ts, so the energy of water = (1-r) MwoCwTs (2)
(3) Input energy (heating amount) P from the outside by the heater is heating amount P = I ² R (3)
Where R is the resistance value of the electric heater 7 and I is the current value.

Next, arrange the energy after melting the sherbet ice.
(4) Energy of water after melting (energy held after melting as seen from the temperature rise) is energy of water after melting = mass of water * specific heat of water * temperature after melting mass of water after melting is Mwo, the specific heat of water is Cw, the temperature of water after dissolution is Two
Therefore, the energy of water after melting = MwoCwTwo (4)
(5) Latent heat, that is, the energy consumed for ice to become water without contributing to temperature rise is latent heat = mass of ice * latent heat of ice (per unit mass)
Ice mass is r * Mwo, ice latent heat (per unit mass) is L
Therefore, latent heat = rMwoL (5)

式（７）の分母、分子に−１を掛け、分数の表現を／で書き直すと
氷濃度ｒは、
ｒ＝｛Ｐ＋（Ｔｓ−Ｔｗｏ）ＣｗＭｗｏ｝／Ｍｗｏ（Ｌ＋（Ｃｗ−Ｃｉ）Ｔｓ）（８）
となる。
但し、Ｐ＝Ｉ^２Ｒ Ｍｗｏ＝ρw＊Ｖ When the energy balance is expressed by the fact that the energy before melting and the energy after melting are equal, (1) + (2) + (3) = (4) + (5).
Therefore, rMwoCiTs + (1-r) MwoCwTs + P = MwoCwTwo + rMwoL (6)
However, Mwo = ρw * V
From equation (6), r (MwoCiTs-MwoCwTs-MwoL) = MwoCwTwo-MwoCwTs-P
Therefore, rMwo (CiTs−CwTs−L) = CwMwo (Two−Ts) −P
From the above, equation (7) is obtained.

Multiplying the denominator and numerator of equation (7) by -1 and rewriting the fractional expression with / gives the ice concentration r as
r = {P + (Ts−Two) CwMwo} / Mwo (L + (Cw−Ci) Ts) (8)
It becomes.
However, P = I ² R Mwo = ρw * V

  From the above, the calculator 15 is observed with the sherbet ice temperature Ts (T1) observed with the first thermometer 11, the salt water temperature Two (T2) observed with the second thermometer 12, and the flow meter 10. The flow rate V, the current value I observed by the ammeter 14 are input, and the specific heat Cw of water, the specific heat Ci of ice, and the density ice concentration of the water after melting are already stored in the memory of the calculator 15. The ice concentration r can be measured by calculating from ρw and the latent heat L of the ice based on Equation 8, and is output as an ice concentration output value 16.

Embodiment 2. FIG.
A second embodiment of the present invention will be described with reference to FIG. In the first embodiment, since the output value of the power supply 13 is fixed, the temperature T2 measured by the second thermometer 12 is high when the ice concentration is low, and is measured by the second thermometer 12 when the ice concentration is high. The temperature T2 is low and the ice may not melt. In the second embodiment, the ice concentration can be accurately calculated by adding a control function capable of keeping the water temperature after melting the ice at a constant value regardless of the ice concentration. Is.

In FIG. 2, the output controller 17 can change the output value of the power source 13 based on the temperature T <b> 2 measured by the second thermometer 12. Other configurations are the same as those described in the first embodiment, and a description thereof will be omitted. FIG. 3 shows a detailed circuit of the output controller 17, and as shown in FIG. 3, the memory 17a set to a predetermined temperature, the temperature set in the memory 17a and the second thermometer 12 were measured. The comparator 17b compares the measured temperature T2 and controls the voltage of the power source 13 based on the temperature difference.
The temperature T2 measured by the second thermometer 12 is preferably as low as possible on the premise that the ice is completely melted. Therefore, the temperature set value set in the memory 17a is in the range of 10 to 20 ° C.

When the measured temperature T2 measured by the second thermometer 12 is lower than the set temperature set in the memory 17a, the comparator 17b raises the output value of the power source 13, and the ice in the heating container 5 is completely removed. Try to melt. On the other hand, when the measured temperature T2 measured by the second thermometer 12 is higher than the set temperature set in the memory 17a, the comparator 17b decreases the output value of the power supply 13. Thus, by maintaining the temperature T2 measured by the second thermometer 12 at an appropriate constant value, the ice concentration can be accurately calculated regardless of the ice concentration introduced into the heating container 5.
In short, the power supply 13 according to the second embodiment has a control function capable of keeping the water temperature derived from the heating container 5 at a predetermined value.

Embodiment 3 FIG.
Embodiment 3 of the present invention will be described with reference to FIGS. In the first and second embodiments, the stirring blade 6 is provided in order to completely melt the ice in the heating container 5. However, by attaching the stirring blade 6, the mechanism becomes complicated and the reliability decreases, There was a problem of deterioration of measurement accuracy due to temperature rise due to change of power to heat due to stirring.
In Embodiment 3, these problems are eliminated. FIG. 4 is a front view of the heating container 5 used in Embodiment 3 of the present invention, and FIG. FIG. 5B is an enlarged view showing a state of the sherbet ice 2 in the heating container 5.

4 and 5, the heating container 5 is an elongated cylindrical container, and an electric heater 7 is placed therein, and the shape of the electric heater 7 is coiled so that turbulence is generated around it to easily melt ice. And At this time, the coil diameter of the coiled electric heater 7 is set to about 60% of the inner diameter of the heating container 5. That is, the coil of the electric heater 7 is arranged so as to be removed from the central portion and the outer edge portion of the heating container 5.
Thus, when the coil diameter of the electric heater 7 is set to about 60% of the inner diameter of the heating container 5, the sherbet ice 2 between the inner side (about 40% area) and the outer side (about 60% area) of the coil of the electric heater 7 is used. Accelerates the flow of water and promotes heat transfer by creating intense turbulence. Further, the sherbet ice 2 is blocked by the heater wire of the electric heater 7 and becomes a turbulent state, and the fine ice 18 receives heat from the heater wire and melts quickly by promoting heat transfer. Therefore, rapid melting is possible without using a stirring blade.
Furthermore, since the coil of the electric heater 7 does not exist at the center and outer edge of the heating container 5 of the elongated cylindrical container, the heating container 5 has an inlet side (left side in FIG. 4) to an outlet side (right side in FIG. 4). The flow of the sherbet ice 2 is performed smoothly.

Embodiment 4 FIG.
Embodiment 4 of the present invention will be described with reference to FIG. In the third embodiment, the coiled electric heater 7 is placed in the heating container 5 to eliminate the need for the stirring blade. However, due to the influence of gravity, ice accumulates on the upper part of the heating container 5 and flows out to the outside as it is. There was a possibility.
In the fourth embodiment, the heating vessel 5 is placed vertically, and the sherbet ice 2 is introduced from the upper part and discharged from the lower part, whereby the light fine ice 18 floats upward, and the sherbet ice 2 flows out without melting as it is. Can be prevented. Therefore, the measurement accuracy of the ice concentration can be increased.

  In each of the above embodiments, sherbet ice was manufactured from seawater and the ice concentration was measured. However, the present invention is not limited to seawater but manufactured from fresh water or other components. This can also be applied to measuring the ice concentration of sherbet ice.

It is a block diagram which shows Embodiment 1 of this invention. It is a block diagram which shows Embodiment 2 of this invention. It is a block diagram of the output controller used for Embodiment 2 of this invention. It is a front view of the heating container used for Embodiment 3 of this invention. It is sectional drawing of the heating container used for Embodiment 3 of this invention. It is a front view of the heating container used for Embodiment 4 of this invention.

Explanation of symbols

1: Ice storage tank 2: Sherbet ice 3: Manual valve 4: Sherbet ice piping 5: Heating vessel 6: Stirring blade 7: Electric heater 8: Discharge pipe 9: Metering pump 10: Flow meter 11: First thermometer 12: Second thermometer 13: Power supply 14: Ammeter 15: Calculator 16: Ice concentration output value 17: Output controller 18: Fine ice

Claims (3)

A cylindrical container heating container into which sherbet ice is introduced, a coil-shaped electric heater provided in the heating container for heating and melting the sherbet ice, a power supply for supplying electric power to the electric heater, introduced into the heating container A first thermometer for measuring the temperature of the sherbet ice before the second thermometer, a second thermometer for measuring the temperature of the water after melting the sherbet ice derived from the heating container, and the first temperature meter derived from the heating container. A flow meter that measures the flow rate of water after melting sherbet ice, and when the temperature measured by the second thermometer is lower than a set temperature, the output value of the power supply is increased and measured by the second thermometer. If the temperature is higher than the set temperature by varying the output value of the power source so as to lower the output value of the power supply, the output system to maintain the temperature of the water is derived from the heating container to a predetermined value Input the temperature measured by the first thermometer and the second thermometer, the flow rate measured by the flow meter, and the current value flowing from the power source to the electric heater, and calculate them An ice concentration meter provided with a calculator for measuring the ice concentration of the sherbet ice.   2. The ice concentration meter according to claim 1, wherein the heating container is placed vertically, the sherbet ice is introduced from an upper portion thereof, and water after the sherbet ice is melted is derived from the lower portion thereof. According to claim 1 or 2 ice densitometer, ice densitometer, characterized in that the diameter of the coil before Symbol electric heater was 60% of the inner diameter of the heating vessel.

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