CN202404046U - Device for measuring undercooling point and freezing point of fruit and vegetable living tissue - Google Patents

Abstract

The utility model discloses a device for measuring an undercooling point and a freezing point of a fruit and vegetable living tissue. The device comprises a constant temperature water bath tank and a constant temperature water bath kettle. A copper plate base, a semiconductor refrigeration chip, a fruit and vegetable sample tank and an upper cover are arranged in the constant temperature water bath kettle, the semiconductor refrigeration chip is powered by a regulated power supply, a T-shaped thermocouple is arranged in the fruit and vegetable sample tank, the T-shaped thermocouple is connected with a data acquisition instrument, and temperature data collected by the data acquisition instrument are transmitted to a computer to be processed. A measuring method includes firstly opening the constant temperature water bath tank and the constant temperature water bath kettle, setting the temperature to be 15 DEG C, adjusting the output power of the regulated power supply according to power requirements of different semiconductor refrigeration chips, cutting a fruit and vegetable sample to be a fixed size according to requirements, placing the cut fruit and vegetable sample in the fruit and vegetable sample tank, and transmitting the temperature data real-timely collected by the data acquisition instrument to the computer to be monitored. The device for measuring the undercooling point and the freezing point of the fruit and vegetable living tissue is wide in application range, simple in structure, easy to implement and convenient to operate, and the measuring time is shortened.

Description

The measurement mechanism of a kind of fruits and vegetables living tissue undercooling point, freezing point

Technical field

The utility model relates to the fresh-keeping field of fruits and vegetables Icetemperature Storage, is specifically related to the measurement mechanism of a kind of fruits and vegetables living tissue undercooling point, freezing point.

Background technology

Existing postharvest technology of fruits and vegetables mainly adopts chemical agent and freezing two kinds of methods.Adopt the fresh-keeping meeting of chemical agent to pollute, bring harm, and freshness date is short to human health.Freeze preservation is fruits and vegetables to be placed adopt certain equipment to freeze, can artificially control and keep stablizing in the environment of low temperature, to keep fruits and vegetables fresh.The critical ice temperature storage can suppress the vital movement of fruits and vegetables to greatest extent, and the senescence process of control fruits and vegetables is considered to a kind of method of storage fruit and vegetable preferably, and the freezing point temperature of fruits and vegetables is one of main reference conditions of confirming its suitable reserve temperature.So, when adopting the critical ice temperature storage, need know the undercooling point and the freezing point of fruits and vegetables in advance, yet its undercooling point of different fruit and vegetables, freezing point are all inequality, so before fruits and vegetables are adopted freeze preservation, need measure undercooling point, the freezing point of fruits and vegetables.

The fruits and vegetables living tissue is different with the freezing point of dead tissue, when living tissue is frozen, at first forms ice crystal in the space between cells; The expansion of ice crystal will rely on the moisture of cell interior to exosmosis; And because cellular plasm is met cold contraction, can hinder moisture passes through, so the relatively difficulty of freezing; Living tissue is breathed and will be emitted part heat simultaneously, and this also makes freezing point descend to some extent; Protoplasm sex change in the dead tissue of fruits and vegetables, moisture can freely pass through at iuntercellular, and therefore, freezing is simple physical process, and the freezing point of the dead tissue of fruits and vegetables only is decided by the concentration of solution.

In the prior art,, there is the people directly to insert the fruits and vegetables organization internal with thermopair in order to obtain the freezing point of fruits and vegetables tissue; Put into-40 ℃ of cryogenic freezing casees and lower the temperature, still, because the fruits and vegetables individual difference; The fruits and vegetables rate of temperature fall that volume is bigger is very slow, and its experimental period is also very long, is not easy to measure freezing point.

The utility model content

The utility model purpose is to provide the measurement mechanism of a kind of fruits and vegetables living tissue undercooling point, freezing point; It is simple and compact for structure, with low cost, can measure various fruits and vegetables living tissue undercooling points, freezing point easily, and the measuring method of fruits and vegetables living tissue undercooling point, freezing point also is provided simultaneously.

The utility model is realized through following technical scheme:

The measurement mechanism of a kind of fruits and vegetables living tissue undercooling point, freezing point comprises constant water bath box, thermostat water bath, and said constant water bath box, thermostat water bath all provide the circulation of isoperibol; The unify circulation of thermostat water bath of the circulating water of said constant water bath box links, and the bottom of thermostat water bath is equipped with the copper coin base, and this is equipped with semiconductor chilling plate above copper coin base; Said semiconductor chilling plate is supplied power by a stabilized voltage supply; Said semiconductor chilling plate upper surface after energising becomes huyashi-chuuka (cold chinese-style noodles), and lower surface becomes hot side, and the temperature difference of said huyashi-chuuka (cold chinese-style noodles) and hot side is fixed; Be equipped with the fruits and vegetables sample cell processed by thermal insulation material above this semiconductor chilling plate; Hold the fruits and vegetables sample in the said fruits and vegetables sample cell, be equipped with the loam cake processed by thermal insulation material above the said fruits and vegetables sample cell, said fruits and vegetables sample cell is built-in with T type thermopair; This T type thermopair connects a data collecting instrument; The upper surface of this T type thermocouple measurement fruits and vegetables sample, the variation of underlaying surface temperature, and by said data collecting instrument collection, this data collecting instrument is transferred to a computing machine with the temperature data of gathering and handles.

Further, scribble heat-conducting silicone grease between the hot side of said semiconductor chilling plate and the copper coin base.

Further, the huyashi-chuuka (cold chinese-style noodles) of said semiconductor chilling plate has an aluminium foil,

Further, scribble heat-conducting silicone grease between the huyashi-chuuka (cold chinese-style noodles) of said semiconductor chilling plate and the aluminium foil.

Further, size, the shape of the size of said fruits and vegetables sample, shape and fruits and vegetables sample cell are complementary, and tight between said fruits and vegetables sample and the fruits and vegetables sample cell.

Further, said copper coin base, semiconductor chilling plate, fruits and vegetables sample cell and loam cake all place in the said thermostat water bath.

Further, said data collecting instrument adopts the FLUKE data collecting instrument.

Further, the said semiconductor chilling plate switch of connecting.

The measurement mechanism of a kind of fruits and vegetables living tissue undercooling point, freezing point, its measuring method comprises the steps:

(1) at first, constant water bath box, thermostat water bath are opened, and temperature is set to 15 ℃, remain on 15 ℃ constant temperature to guarantee the inner environment of copper coin base and thermostat water bath;

(2) open switch, regulate the output power of stabilized voltage supply according to the power requirement of different semiconductor chilling plates;

(3) the fruits and vegetables sample is cut into fixed measure as requested and puts into the fruits and vegetables sample cell, the fruits and vegetables sample is identical with size, the thickness of fruits and vegetables sample cell, and tight between fruits and vegetables sample and the fruits and vegetables sample cell;

(4) data collecting instrument is set at TS and gathers a temperature data (T＞0S); And the temperature data that data collecting instrument is gathered in real time is transferred on the computing machine monitors; After the temperature of setting in fruits and vegetables sample temperature and the thermostat water bath is consistent, open switch, the cooling rapidly of semiconductor chilling plate energising back; The temperature variation of T type thermopair real time record fruits and vegetables sample; The real-time image data of data collecting instrument also is transferred to computing machine, just can see the temperature lowering curve of fruits and vegetables sample through Computer Processing, and then obtain the data of undercooling point, freezing point.

Further, can adjust the size of fruits and vegetables sample voluntarily according to the difference of fruits and vegetables kind in the said step (3), the size of fruits and vegetables sample cell also should change thereupon simultaneously.

Beneficial effect: the measurement mechanism and the measuring method thereof of fruits and vegetables living tissue undercooling point, freezing point in the utility model, can test living tissue undercooling point of various fruits and vegetables and freezing point, the scope of application is very wide; Have simple in structurely, realize easily easy to operate advantage; When measuring, the external environment influence is little, and rate of temperature fall is fast, shortens greatly and measures the used time.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is further specified.

Fig. 1 is the structural representation of an embodiment of measurement mechanism in the utility model.

Fig. 2 is the temperature lowering curve figure of an embodiment in the utility model.

Among the figure: 1. constant water bath box; 2. thermostat water bath; 3. semiconductor chilling plate; 4. copper coin base; 5. stabilized voltage supply; 6.T type thermopair; 7. data collecting instrument; 8. computing machine; 9. aluminium foil; 10. fruits and vegetables sample cell; 11. loam cake; 12. heat-conducting silicone grease; 13. switch.

Embodiment

Embodiment to the utility model elaborates below in conjunction with accompanying drawing: present embodiment is being to implement under the prerequisite with the utility model technical scheme; Provided detailed embodiment and concrete operating process, but the protection domain of the utility model is not limited to following embodiment.

As shown in Figure 1, comprise constant water bath box 1, thermostat water bath 2 among the figure, constant water bath box 1, thermostat water bath 2 all provide the circulation of isoperibol, and the unify circulation of thermostat water bath 2 of the circulating water of constant water bath box 1 links.Thermostat water bath 2 is built-in with copper coin base 4, semiconductor chilling plate 3, fruits and vegetables sample cell 10 and loam cake 11, makes the temperature constant of fruits and vegetables sample surrounding environment.

Copper coin base 4 places the bottom of thermostat water bath 2, is equipped with semiconductor chilling plate 3 above the copper coin base 4.Semiconductor chilling plate 3 is by a stabilized voltage supply 5 power supply, and by the switching of switch 13 control circuits.Open switch 13, become huyashi-chuuka (cold chinese-style noodles) at semiconductor chilling plate 3 upper surface after energising, lower surface becomes hot side, and the temperature difference of huyashi-chuuka (cold chinese-style noodles) and hot side is fixed.Huyashi-chuuka (cold chinese-style noodles) is in order to drop to lower temperature, and hot side also will be lowered the temperature thereupon, and the hot side of semiconductor chilling plate 3 is close on the copper coin base 4, utilizes the recirculated water in the constant water bath box 1 to give the copper coin base 4 coolings.Simultaneously, in order between the hot side that guarantees semiconductor chilling plate 3 and the copper coin base 4 good heat interchange to be arranged, between the hot side of semiconductor chilling plate 3 and copper coin base 4, scribble heat-conducting silicone grease 12.The huyashi-chuuka (cold chinese-style noodles) of semiconductor chilling plate 3 also scribbles heat-conducting silicone grease 12 with aluminium foil 9 between the huyashi-chuuka (cold chinese-style noodles) of semiconductor chilling plate 3 and the aluminium foil 9, and is even with the temperature that guarantees semiconductor chilling plate 3 huyashi-chuuka (cold chinese-style noodles).

Fruits and vegetables sample cell 10, loam cake 11 all are to be processed by thermal insulation material; Hold the fruits and vegetables sample in the fruits and vegetables sample cell 10; Size, shape, the thickness of the size of fruits and vegetables sample, shape, thickness and fruits and vegetables sample cell are complementary; And the fruits and vegetables sample fills up fruits and vegetables sample cell 10, tight between fruits and vegetables sample and the fruits and vegetables sample cell 10.The fruits and vegetables sample is put into fruits and vegetables sample cell 10 after cutting according to fixed measure, is positioned on the huyashi-chuuka (cold chinese-style noodles) of semiconductor chilling plate 3 again, covers loam cake 11 again.

The fruits and vegetables sample cell is built-in with T type thermopair, and T type thermopair 6 is used for measuring the upper surface of fruits and vegetables sample, the temperature variation of lower surface, and T type thermopair 6 connects data collecting instrument 7, and data collecting instrument 7 adopts the FLUKE data collecting instrument.T type thermopair 6 is measured the upper surface of fruits and vegetables sample, the variation of underlaying surface temperature; And by data collecting instrument 7 collecting temperature data; Data collecting instrument 7 is transferred to computing machine 8 with the temperature data of gathering and carries out data processing; And on the display screen of computing machine 8 the video data process result, supply the experimenter to check.

Under the guidance of thermal conduction study basic theories; The fruits and vegetables sample cell of placing the fruits and vegetables sample is to be processed by thermal insulation material; So can regard the fruits and vegetables sample as the semiinfinite massive plate under certain condition, consistent with the surface temperature of semiconductor chilling plate contact, semiconductor chilling plate gives constant cold; Cold extends along the radial direction of fruits and vegetables sample, carries out heat interchange.

Boundary condition is second type of boundary condition, in the time interval [0, τ] interior semiinfinite massive plate surface and extraneous heat (that is the heat conduction amount in the semiinfinite massive plate)

Heat flow density through arbitrary section x place:

$q_x=-\mathrm{\λ}\frac{\∂t}{\∂x}=-\mathrm{\λ}(t_0-t_w)\frac{\∂\mathrm{erf\η}}{\∂x}$

$=\mathrm{\&lambda;}\frac{t_w-{\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="HDA0000124736310000011.png"\; state="\{\{state\}\}">t</figure-callout>}}_0}{\sqrt{\mathrm{\&pi;a\&tau;}}}\exp [-x^2/\left(4\mathrm{a\&tau;}\right)]$

Heat conduction amount from the teeth outwards is:

$Q=A{\&Integral;}_0^{\mathrm{\&tau;}}{q}_w\mathrm{d\&tau;}=A{\&Integral;}_0^{\mathrm{\&tau;}}\frac{\mathrm{\&lambda;}(t_w-t_0)}{\sqrt{\mathrm{\&pi;a\&tau;}}}\mathrm{d\&tau;}=2A\sqrt{\frac{\mathrm{\&tau;}}{\mathrm{\&pi;}}}\sqrt{\mathrm{\&rho;c\&lambda;}}(t_w-t_0)$

Can find out that from following formula total heat conduction amount is directly proportional with the square root of time, also be directly proportional with

of object.For different fruits and vegetables tissues different density and specific heat are arranged, coefficient of heat conductivity is also different, and its undercooling point is different with freezing point, and the time of arrival freezing point also is different.

Embodiment:

Be example below with the cucumber, measure living tissue undercooling point and the freezing point of cucumber, its measuring method comprises the steps:

(a) at first, constant water bath box 1, thermostat water bath 2 are opened, and temperature is set to 15 ℃, remain on 15 ℃ constant temperature to guarantee copper coin base 4 and thermostat water bath 3 inner environment;

(b) open switch 13, regulate the output power of stabilized voltage supply 5 according to the power requirement of different semiconductor chilling plate 3;

(c) the cucumber sample is cut into fixed measure as requested and puts into fruits and vegetables sample cell 10, the cucumber sample is identical with size, the thickness of fruits and vegetables sample cell 10, and tight between cucumber sample and the fruits and vegetables sample cell 10;

(d) adopt the FLUKE data collecting instrument, the FLUKE data collecting instrument is set at 1S gathers a temperature data, and the temperature data that the FLUKE data collecting instrument is gathered in real time is transferred on the computing machine 8 monitors; After the temperature of setting in cucumber sample temperature and the thermostat water bath 2 is consistent; Open switch 13, semiconductor chilling plate 3 energising back coolings rapidly, the temperature variation of T type thermopair 6 real time record cucumber samples; The real-time image data of FLUKE data collecting instrument also is transferred to computing machine 8; Just the temperature lowering curve of cucumber sample be can see through Computer Processing, and then the living tissue undercooling point of cucumber, freezing point obtained, as shown in Figure 2.

More than show and described ultimate principle of the utility model and the advantage of principal character and the utility model.The technician of the industry should understand; The utility model is not restricted to the described embodiments; The principle of describing in the foregoing description and the instructions that the utility model just is described; Under the prerequisite that does not break away from the utility model spirit and scope, the utility model also has various changes and modifications, and these variations and improvement all fall in the utility model scope that requires protection.The utility model requires protection domain to be defined by appending claims and equivalent thereof.

Claims (8)

1. the measurement mechanism of a fruits and vegetables living tissue undercooling point, freezing point is characterized in that, comprises constant water bath box, thermostat water bath; Said constant water bath box, thermostat water bath all provide the circulation of isoperibol, and the unify circulation of thermostat water bath of the circulating water of said constant water bath box links, and the bottom of thermostat water bath is equipped with the copper coin base; This is equipped with semiconductor chilling plate above copper coin base, and said semiconductor chilling plate is supplied power by a stabilized voltage supply, and said semiconductor chilling plate upper surface after energising becomes huyashi-chuuka (cold chinese-style noodles); Lower surface becomes hot side; And the temperature difference of said huyashi-chuuka (cold chinese-style noodles) and hot side is fixed, and is equipped with the fruits and vegetables sample cell processed by thermal insulation material above this semiconductor chilling plate, holds the fruits and vegetables sample in the said fruits and vegetables sample cell; Be equipped with the loam cake processed by thermal insulation material above the said fruits and vegetables sample cell; Said fruits and vegetables sample cell is built-in with T type thermopair, and this T type thermopair connects a data collecting instrument, the upper surface of this T type thermocouple measurement fruits and vegetables sample, the variation of underlaying surface temperature; And by said data collecting instrument collection, this data collecting instrument is transferred to a computing machine with the temperature data of gathering and handles.

2. the measurement mechanism of a kind of fruits and vegetables living tissue undercooling point according to claim 1, freezing point is characterized in that, scribbles heat-conducting silicone grease between the hot side of said semiconductor chilling plate and the copper coin base.

3. the measurement mechanism of a kind of fruits and vegetables living tissue undercooling point according to claim 1, freezing point is characterized in that, the huyashi-chuuka (cold chinese-style noodles) of said semiconductor chilling plate has an aluminium foil,

4. the measurement mechanism of a kind of fruits and vegetables living tissue undercooling point according to claim 3, freezing point is characterized in that, scribbles heat-conducting silicone grease between the huyashi-chuuka (cold chinese-style noodles) of said semiconductor chilling plate and the aluminium foil.

5. the measurement mechanism of a kind of fruits and vegetables living tissue undercooling point according to claim 1, freezing point; It is characterized in that; Size, the shape of the size of said fruits and vegetables sample, shape and fruits and vegetables sample cell are complementary, and tight between said fruits and vegetables sample and the fruits and vegetables sample cell.

6. the measurement mechanism of a kind of fruits and vegetables living tissue undercooling point according to claim 1, freezing point is characterized in that said copper coin base, semiconductor chilling plate, fruits and vegetables sample cell and loam cake all place in the said thermostat water bath.

7. the measurement mechanism of a kind of fruits and vegetables living tissue undercooling point according to claim 1, freezing point is characterized in that, said data collecting instrument adopts the FLUKE data collecting instrument.

8. the measurement mechanism of a kind of fruits and vegetables living tissue undercooling point according to claim 1, freezing point is characterized in that, the said semiconductor chilling plate switch of connecting.

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