CN105815445B - Thawing method for frozen concentrated milk - Google Patents

Abstract

The invention provides a method for thawing frozen concentrated milk, which uses a cutting machine to cut large frozen concentrated milk ice cubes to form frozen concentrated milk ice chips, and then sends them to a heat exchanger for preliminary heating to make frozen concentrated milk ice. The chips are melted to form a frozen concentrated milk slurry, and finally the frozen concentrated milk slurry is put into a dissolving barrel with hot water for heating, dissolving, stirring and mixing to form a milk raw material that is convenient for subsequent processing. The frozen concentrated milk thawing method of the present invention can improve the thawing efficiency, retain the flavor of the milk raw materials, and completely melt the frozen concentrated milk ice cubes.

Description

Frozen Concentrated Milk Thawing Method

technical field

The invention relates to a method for thawing frozen and concentrated milk, in particular to a method of cutting frozen and concentrated milk ice cubes by means of a cutting machine, and then using a heat exchanger to initially heat the frozen and concentrated milk ice chips, thereby improving the quality of the frozen and concentrated milk. The thawing efficiency is improved to achieve the purpose of increasing the production capacity of frozen concentrated milk into dairy products.

Background technique

In the prior art thawing method of frozen concentrated milk, the ice cubes of frozen concentrated milk are generally taken out from the freezer, placed in a refrigerated thaw at 4-7°C for 48-72 hours, and then put into a dissolving bucket and mixed with hot water. And the temperature is raised to 60° C. to form semi-finished liquid milk raw material.

However, the heating of the dissolving barrel of the existing method needs the assistance of other heating equipment. If the heating auxiliary equipment of the dissolving barrel is steam heating, it is easy to produce coking substances in the barrel, which affects the taste of frozen concentrated milk; if the heating of the dissolving barrel The auxiliary equipment is water circulation heating, which not only raises the temperature slowly and takes a long time, but also tends to contain frozen hard blocks due to the incomplete melting of the naturally thawed frozen concentrated milk ice cubes continuously put into the dissolving tank, which makes the heating efficiency of the dissolving tank poor, and The frozen hard block is easy to cause damage to the stirrer in the dissolving bucket because it is difficult to stir. Therefore, at this stage, there is a need for a thawing method for frozen condensed milk that can improve the thawing efficiency, does not affect the flavor of the milk raw material, and does not cause damage to the stirrer due to frozen hard lumps.

Contents of the invention

In order to solve the problem that steam heating easily affects the taste of frozen condensed milk in the prior art, while water circulation heating is slow to heat up and easily dissolves frozen condensed milk. A frozen condensed milk thawing method in which ice cubes of frozen condensed milk are completely thawed.

In order to achieve the above-mentioned purpose of the invention, the technical means adopted in the present invention is to provide a method for thawing frozen concentrated milk, which comprises the following steps:

Cutting, using a cutting machine to cut the frozen condensed milk ice cubes to form frozen condensed milk ice chips, and then sending the frozen condensed milk ice chips into a heat exchanger with a heating tube;

Preliminary heating, using the heating tube in the heat exchanger to initially heat the frozen condensed milk ice chips, melting the frozen concentrated milk ice chips to form a frozen concentrated milk puree, and then the frozen concentrated milk puree The solid is dropped into a dissolving bucket; and

Warming up and dissolving, adding hot water into the dissolving barrel to raise the temperature, heating and dissolving the frozen concentrated milk puree in the dissolving barrel again, and completely dissolving the frozen concentrated milk puree in the The semi-finished product of liquid milk raw material is formed in hot water.

The beneficial effect of the present invention is that the original large block of frozen concentrated milk ice is cut into a plurality of frozen concentrated milk ice chips by simply using the cutting step, and then the multiple frozen concentrated milk ice chips are sent to the heat exchanger by the preliminary heating step Heating in the medium first, so that the frozen condensed milk ice chips are melted before being put into the dissolving bucket to form a frozen condensed milk slurry, and finally, the hot water is used to dissolve and stir again, and the frozen condensed milk slurry is completely dissolved in the hot water. In the water, the liquid milk raw material semi-finished product is formed. The above cutting and preliminary heating steps enable the ice cubes of frozen concentrated milk to be melted quickly and mixed with hot water for stirring, so that the frozen concentrated milk put into the melting bucket for stirring will not have large frozen lumps, effectively avoiding the damage of the agitator , and reduce the production time, and increase the production capacity of frozen concentrated milk into dairy products.

Preferably, a pump is arranged between the cutting machine and the heat exchanger. This technical method simply uses the pump to pump the frozen concentrated milk ice chips cut by the cutting machine into the heat exchanger for preliminary heating. It is transported at a stable speed in the heat exchanger to avoid excessive heating, so that there will be less coke in the heat exchanger, which can effectively preserve the flavor of milk raw materials and avoid the burnt smell of coke from affecting the quality of dairy products.

More preferably, the heat exchanger is a jacketed tube heat exchanger, a shell and tube heat exchanger or a plate heat exchanger, and the jacketed tube heat exchanger is preferred. This technical means utilizes the above-mentioned heat exchanger as the heating tool for preliminary heating of the present invention, so that the frozen condensed milk ice crumbs are further melted to form a frozen condensed milk slurry by heat exchange reaction with the medium in the heat exchanger, and then put into Mix and stir with hot water in a dissolving bucket. Among them, after consideration and evaluation of many factors such as heat exchange capacity, production pressure, fouling degree, cleaning difficulty and equipment investment cost, the jacketed tube heat exchanger is the best choice, but users can also use the jacket Any replacement of the tube heat exchanger with a shell-and-tube heat exchanger or a plate heat exchanger, or even other types of heat exchangers not mentioned in this case, will not affect the thawing method of frozen concentrated milk provided in this case. effect.

Description of drawings

The method for thawing frozen concentrated milk of the present invention will be described in further detail below in conjunction with the accompanying drawings and examples.

Fig. 1 is a schematic perspective view of a jacketed tube heat exchanger of the present invention.

Fig. 2 is a schematic cross-sectional view of the diameter of the heating tube of the jacketed tube heat exchanger of the present invention.

Fig. 3 is a schematic perspective view of the shell-and-tube heat exchanger of the present invention.

Fig. 4 is a schematic cross-sectional view of the diameter of the heating tube of the shell-and-tube heat exchanger of the present invention.

Fig. 5 is a schematic perspective view of the plate heat exchanger of the present invention.

Fig. 6 is a schematic cross-sectional view of the plate structure of the plate heat exchanger of the present invention.

Explanation of reference signs: 10. Jacketed tube heat exchanger, 11. Heating tube, 111. Inner tube, 112. Outer tube, 20. Shell and tube heat exchanger, 21. Heating tube, 211. Inner tube , 211A. Microtube, 212. Outer tube, 30. Plate heat exchanger, 31. Heating plate, 311. Heating tube.

Detailed ways

In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation manners of the present invention will now be described with reference to the accompanying drawings.

Example 1

The method for thawing frozen concentrated milk in this embodiment is as follows: take 1 ton of -18°C frozen concentrated milk ice cubes out of the freezer, and directly use a cutting machine to cut the frozen concentrated milk ice cubes into frozen concentrated milk ice chips, and then The frozen condensed milk chips are pumped out, and then sent to a jacketed tube heat exchanger for preliminary heating. The jacketed tube heat exchanger uses hot water at 70°C to 80°C as a heat source to heat the frozen condensed milk. Milk ice chips melt and continue to heat up to 30°C to 40°C, and the cutting and preliminary heating work efficiency is 1 ton/hour to 1.5 tons/hour, that is, it can cut and heat 1 ton to 1.5 tons per hour Freeze condensed milk ice cubes and ice chips.

Then put the frozen condensed milk slurry formed after the initial heating and melting of the frozen condensed milk ice chips into the dissolving bucket, and at the same time add hot water from 60°C to 75°C to the dissolving bucket to heat up and dissolve and stir, so that the liquid in the dissolving bucket The frozen condensed milk puree was once again heated and dissolved for 5 to 15 minutes, and completely dissolved in hot water to finally form a semi-finished liquid milk raw material. Example 1 It takes about 1.1 hours to 1.5 hours from the ice cubes of frozen concentrated milk at -18°C taken out of the freezer until the frozen concentrated milk puree is completely dissolved in hot water to form a semi-finished liquid milk raw material.

Example 2

The method for thawing frozen concentrated milk in this embodiment is as follows: take out 1 ton of -18°C frozen concentrated milk ice cubes from the freezer, and directly use a cutting machine to cut the frozen concentrated milk ice cubes into frozen concentrated milk ice chips, Then pump the frozen concentrated milk ice chips, and then send them into the shell-and-tube heat exchanger for preliminary heating. Chips melt and continue to heat up to 30°C to 40°C, while the cutting and preliminary heating work efficiency is 1 ton/hour to 1.5 tons/hour, that is, 1 ton to 1.5 tons of frozen concentrated milk ice can be cut and heated per hour Blocks and icicles.

Then put the frozen condensed milk slurry formed after the initial heating and melting of the frozen condensed milk ice chips into the dissolving bucket, and at the same time add hot water from 60°C to 75°C to the dissolving bucket to heat up and dissolve and stir, so that the liquid in the dissolving bucket The frozen condensed milk puree was once again heated and dissolved for 5 to 15 minutes, and completely dissolved in hot water to finally form a semi-finished liquid milk raw material. Example 2 It takes about 1.1 hours to 1.5 hours from the ice cubes of frozen concentrated milk at -18°C taken out of the freezer until the frozen concentrated milk puree is completely dissolved in hot water to form a semi-finished liquid milk raw material.

Example 3

The method for thawing frozen concentrated milk in this embodiment is as follows: take 1 ton of -18°C frozen concentrated milk ice cubes out of the freezer, and directly use a cutting machine to cut the frozen concentrated milk ice cubes into frozen concentrated milk ice chips, and then The frozen condensed milk ice chips are pumped, and then sent to the plate heat exchanger for preliminary heating. The plate heat exchanger uses 70°C to 80°C hot water as the heat source to melt the frozen condensed milk ice chips and continue to heat up to 30°C to 40°C, and the cutting and preliminary heating work efficiency is 1 ton/hour to 1.5 tons/hour, that is, 1 ton to 1.5 tons of frozen condensed milk ice cubes and ice chips can be cut and heated per hour.

Then put the frozen condensed milk slurry formed after the initial heating and melting of the frozen condensed milk ice chips into the dissolving bucket, and at the same time add hot water from 60°C to 75°C to the dissolving bucket to heat up and dissolve and stir, so that the liquid in the dissolving bucket The frozen condensed milk puree was once again heated and dissolved for 5 to 15 minutes, and completely dissolved in hot water to finally form a semi-finished liquid milk raw material. Example 3 It takes about 1.1 hours to 1.5 hours from the ice cubes of frozen concentrated milk at -18°C taken out of the freezer until the frozen concentrated milk puree is completely dissolved in hot water to form a semi-finished liquid milk raw material.

comparative example

The method for thawing frozen concentrated milk in this comparative example is a general process of the prior art: after taking out 1 ton of frozen concentrated milk ice cubes at -18°C from the freezer, place them at 4°C to 7°C for about 48 hours to refrigerate and thaw. 72 hours (it takes about 72 hours to thaw at 4°C, and about 48 hours to thaw at 7°C), then put the incompletely thawed frozen concentrated milk solid and liquid mixture into the dissolving bucket, mix it with hot water at 75°C, and heat Equipment (steam heating or water circulation heating) assists in raising the temperature to 60°C to 75°C, while stirring with a stirrer for 20 minutes to 30 minutes, so that the solid and liquid mixture of frozen concentrated milk is completely dissolved in hot water to form semi-finished liquid milk raw materials . COMPARATIVE EXAMPLE It takes at least 48.5 hours from the ice cube of frozen concentrated milk at -18°C taken out of the freezer until the solid and liquid mixture of the frozen concentrated milk is completely dissolved in hot water to form a semi-finished liquid milk raw material.

Here, the structural characteristics and various advantages and disadvantages of the jacketed tube heat exchangers, shell and tube heat exchangers and plate heat exchangers in Examples 1 to 3 are compared first.

As shown in Figures 1 and 2, the jacketed tube heat exchanger 10 includes curved and stacked heating tubes 11. The heating tubes 11 have a double-layer tube structure, and the inner tube 111 is used to accommodate and transport frozen concentrated milk. , the outer tube 112 is used to accommodate the cold (hot) medium, and by changing the cold (hot) medium in the outer tube 112, the temperature of the frozen condensed milk in the inner tube 111 is raised or lowered.

As shown in Figures 3 and 4, the shell-and-tube heat exchanger 20 includes a straight heating tube 21, which is also a double-layer tube structure, and the inner tube 211 is composed of a plurality of parallel and spaced apart micro-tubes. 211A, used as accommodating and transporting frozen condensed milk, the outer tube 212 is used to accommodate cold (hot) medium, and by changing the cold (hot) medium in the outer tube to raise or lower the temperature of the frozen condensed milk in the inner tube .

As shown in Figures 5 and 6, the plate heat exchanger 30 includes a plurality of stacked heating plates 31, and is composed of multiple sets of heating plates arranged at intervals. Slotted heating pipe 311 is used for accommodating and transporting frozen condensed milk. One side of heating plate 31 is used to accommodate cold (hot) medium, and by changing the cold (hot) medium on one side of heating plate 31 to the heating tube The frozen concentrated milk in 311 is heated or cooled.

Table 1: Advantages and disadvantages of jacketed tube heat exchangers, shell and tube heat exchangers and plate heat exchangers of Embodiments 1 to 3 of the present invention

Jacketed tube heat exchanger shell and tube heat exchanger plate heat exchanger Heating pipe diameter Big middle Small heat exchange capacity Low middle high production pressure Low middle high Scale degree (coke) Low middle high cleaning difficulty Low middle high cost of investment Low high middle

Because of the large diameter of the heating tube 11 of the jacketed tube heat exchanger 10, the total contact area between the frozen condensed milk contained in the heating tube 11 and the tube wall of the heating tube 11 is relatively small, resulting in a jacketed tube heat exchanger. The heat exchange capacity of the heat exchanger 10 is relatively poor; but the pressure (production pressure) of the frozen concentrated milk passing through the heating pipe 11, the degree of fouling in the heating pipe 11, the difficulty of cleaning the heating pipe 11 and the investment cost of the equipment are all relatively low. Therefore, in this case, the jacketed tube heat exchanger 10 is the first preferred choice.

The inner tube 211 of the heating tube 21 of the shell-and-tube heat exchanger 20 is assembled with a plurality of parallel and spaced apart microtubes 211A, and the diameter of the microtubes 211A is smaller than that of the heating tube 11 of the jacketed tube heat exchanger 10. Therefore, the total area of contact between the frozen condensed milk contained in the microtube 211A and the wall of the microtube 211A is relatively large, so that the heat exchange capacity of the shell-and-tube heat exchanger 20 is higher than that of the jacketed tube heat exchanger. 10 is preferred; but the pressure of the heating tube 21 of the frozen concentrated milk passing through the shell-and-tube heat exchanger 20, the degree of fouling in the heating tube 21, the difficulty of cleaning the heating tube 21 and the investment cost of the equipment are all high, so in the cost And considering the convenience of the process, the jacketed tube heat exchanger 10 is still the first priority in this case.

Although the other plate heat exchanger 30 has the best heat exchange capacity, and the investment cost is between the jacketed tube heat exchanger 10 and the shell and tube heat exchanger 20, but the plurality of honeycombs in the heating plate 31 The diameter of the heating pipe 311 is very small, which is not conducive to the transportation of the frozen concentrated milk, and it is easy to cause the coking and fouling of the frozen concentrated milk, and once the fouling is difficult to clean, so even if the equipment investment cost of the plate heat exchanger 30 is low Between the jacketed tube heat exchanger 10 and the shell and tube heat exchanger 20, but subsequent maintenance is very troublesome and tricky, so the jacketed tube heat exchanger 10 is still the first priority in this case.

Then compare the process differences between Examples 1 to 3 and Comparative Example. In Examples 1 to 3, after the frozen concentrated milk ice cubes are taken out from the freezer, the frozen concentrated milk ice cubes are first cut into frozen concentrated milk ice chips by a cutting machine, and then sent to a heat exchanger for preliminary processing. Heating, and finally put the frozen condensed milk slurry formed after the initial heating and melting into the dissolving bucket, mix with hot water and heat up and stir at the same time. Compared with the comparative example, the process of this case is to thaw the frozen condensed milk ice cubes in a natural way , and then put the incompletely melted frozen condensed milk solid and liquid mixture into the dissolving bucket and mix it with hot water, and at the same time use heating equipment to heat up and stir. Embodiments 1 to 3 can more effectively freeze the frozen condensed milk ice cubes. Melting, and there will be no incompletely thawed frozen solids, so that the stirrer will not be damaged due to the existence of frozen solids, and even nearly 97% of the process time of the comparative example can be saved.

In summary, compared with the general process of the prior art, the thawing method of frozen concentrated milk provided in this case has the effect of significantly increasing the thawing rate of frozen concentrated milk and increasing the production capacity of frozen concentrated milk into dairy products; in addition, the frozen concentrated milk in this case The initial heating step after cutting of the milk thawing method makes the frozen concentrated milk put into the dissolving tank for stirring will not have large frozen lumps, effectively avoids the possibility of damage to the agitator, and reduces the cost of the frozen concentrated milk thawing process Equipment maintenance and maintenance costs are also equivalent to reducing the production cost of frozen concentrated milk.

The above descriptions are only illustrative specific implementations of the present invention, and are not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principle of the present invention shall fall within the protection scope of the present invention. And it should be noted that each component of the present invention is not limited to the above-mentioned overall application, and each technical feature described in the description of the present invention can be selected to be used alone or in combination according to actual needs. Therefore, the present invention It should naturally cover other combinations and specific applications related to the innovation of this case.

Claims (3)

1. a kind of freeze concentration cream defreezing method, which is characterized in that the freeze concentration cream defreezing method the following steps are included:

Cutting cuts freeze concentration cream ice cube to form freeze concentration cream ice bits with a cutter, then the freeze concentration is newborn Ice bits are sent into a heat exchanger with heating tube；

Preliminary heating tentatively heats freeze concentration cream ice bits with the heating tube in the heat exchanger, described first The heat source temperature of step heating is 70 DEG C -80 DEG C, and freeze concentration cream ice bits are melted to form freeze concentration cream purees, work Make freeze concentration cream ice cube and the ice bits/hour that efficiency is 1 ton -1.5 tons, then freeze concentration cream purees investment one is molten It solves in bucket；And

Rising temperature for dissolving hot water heating is added in Yu Suoshu dissolving bucket, by the freeze concentration cream purees in the dissolving bucket Rising temperature for dissolving again, and make to be dissolved completely in after the freeze concentration cream purees is agitated and form fluid milk original in hot water Expect semi-finished product.

2. freeze concentration cream defreezing method as described in claim 1, which is characterized in that the cutter and the heat exchanger Between be provided with a pump.

3. freeze concentration cream defreezing method as claimed in claim 1 or 2, which is characterized in that the heat exchanger is jacketed pipe Formula heat exchanger, shell and tube heat exchanger or heat-exchangers of the plate type.