Lactose-free liquid milk production line

Abstract

The lactose-free liquid milk production line comprises a raw milk system, a membrane filtration system and a blending and sterilizing system, the membrane filtration system comprises an ultrafiltration separator, a nanofiltration separator, a reverse osmosis filter and a dilution pipeline, the ultrafiltration separator is provided with a first feed port, a first reserved liquid outlet and a first penetrating fluid outlet, and the nanofiltration separator is provided with a second feed port and a second penetrating fluid outlet; the reverse osmosis filter is provided with a third feeding hole, a third reserved liquid outlet and a third penetrating liquid outlet; the raw milk outlet is communicated with the first feeding hole; the first penetrating fluid outlet is communicated with the second feeding hole; the second penetrating fluid outlet is communicated with the third feeding hole; the first reserved liquid outlet and the third reserved liquid outlet are both communicated with a fourth feeding hole of the blending and sterilizing system; the third penetrating fluid outlet is communicated with a dilution pipeline, and the dilution pipeline is used for diluting liquid entering the ultrafiltration separator and / or the nanofiltration separator. The scheme is beneficial for preventing the liquid milk from losing a large amount of salt ions and also beneficial for reducing the carbohydrate content.

Description

Technical Field

[0001] This utility model relates to the field of dairy product production, and more specifically, to a lactose-free liquid milk production line. Background Technology

[0002] Lactase deficiency (LD) and lactose malabsorption (LM) occur worldwide. It is genetically determined, with intestinal lactase activity gradually decreasing with age. More than 70% of the global population has some degree of lactase deficiency, but the incidence varies by region. The incidence is lower in Northern Europe (approximately 5%), while in Asia it can be as high as 100%. In 20%–60% of individuals with lactose malabsorption, unabsorbed lactose can undergo osmotic pressure and reach the colon, where it is broken down by bacteria, producing short-chain fatty acids and gases such as hydrogen, leading to abdominal symptoms (diarrhea, bloating, abdominal pain, etc.), a condition known as lactose intolerance.

[0003] The main carbohydrate in milk is lactose, a disaccharide composed of galactose and glucose linked by a β-1,4 glycosidic bond. It accounts for approximately 4.8% of milk's total sugar content, or 99.8%. Currently, lactose-free milk on the market primarily utilizes two processing technologies: membrane filtration and lactase hydrolysis. Membrane filtration removes or reduces lactose (carbohydrates) from dairy products through physical methods, resulting in the loss of significant amounts of salt ions (mainly sodium ions), leading to varying degrees of loss in the taste and flavor of the resulting product. On the other hand, lactase hydrolysis converts lactose into glucose and galactose through biocatalysis. While enzymatically breaking down lactose, it doesn't reduce the carbohydrate content. Furthermore, hydrolyzed lactose increases the sweetness of milk, failing to meet the nutritional needs of middle-aged and elderly individuals, as well as diabetics and other consumers requiring blood sugar control. Utility Model Content

[0004] The technical problem to be solved by this application is to provide a lactose-free liquid milk production line, which is beneficial to avoid the loss of a large number of salt ions in fresh milk and to reduce the carbohydrate content in fresh milk.

[0005] This application provides a lactose-free liquid milk production line, including: a raw milk system, a membrane filtration system, and a blending and sterilization system; the raw milk system has a raw milk outlet; the membrane filtration system includes an ultrafiltration separator, a nanofiltration separator, a reverse osmosis filter, and a dilution pipeline, the ultrafiltration separator has a first inlet, a first retention liquid outlet, and a first permeate outlet, the nanofiltration separator has a second inlet and a second permeate outlet, and the reverse osmosis filter has a third inlet, a third retention liquid outlet, and a third permeate outlet; the blending and sterilization system has a fourth inlet; the raw milk outlet is connected to the first inlet. The system is configured to supply raw milk to the ultrafiltration separator; the first permeate outlet is connected to the second inlet and is configured to supply the first permeate to the nanofiltration separator; the second permeate outlet is connected to the third inlet and is configured to supply the second permeate to the reverse osmosis filter; the first retention liquid outlet and the third retention liquid outlet are both connected to the fourth inlet and are configured to supply the first retention liquid and the third retention liquid to the blending and sterilization system; the third permeate outlet is connected to the dilution pipe, which is configured to dilute the liquid entering the ultrafiltration separator and / or the nanofiltration separator.

[0006] The lactose-free liquid milk production line provided in this application uses membrane filtration technology to remove most of the lactose from raw milk, thereby reducing the carbohydrate content of fresh milk. This results in a low GI (Glycemic Index), which is beneficial for meeting the nutritional needs of middle-aged and elderly people, as well as diabetics and other consumers who require blood sugar control. Furthermore, most of the salt ions in the raw milk are concentrated by reverse osmosis filtration and then transported to the blending and sterilization system, achieving salt ion recovery. This helps avoid the loss of large amounts of salt ions, thus preserving the taste and flavor of the fresh milk and improving its nutritional value. It also eliminates the need for additional salt ion supplements to enhance the taste and flavor of the fresh milk, simplifying the ingredient list and improving the product's market competitiveness.

[0007] In addition, the third permeate output from the reverse osmosis filter is recycled back to the membrane filtration system through a dilution pipeline, which can dilute the liquid entering the ultrafiltration and nanofiltration separators, thereby improving the working efficiency of the ultrafiltration and nanofiltration separators. Furthermore, no additional diluent is required, which also helps to simplify the ingredient list of fresh milk and enhance the product's market competitiveness.

[0008] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objectives and other advantages of this invention can be realized and obtained by means of the structures particularly pointed out in the description and the accompanying drawings. Attached Figure Description

[0009] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0010] Figure 1 This is a schematic diagram illustrating the principle of a lactose-free liquid milk production line provided in some embodiments of this application.

[0011] The attached diagram lists the components represented by each number as follows:

[0012] 100 Raw milk system, 102 Raw milk storage tank, 104 Milk purifier, 106 Purified milk temporary storage tank, 108 Second sterilizer, 110 Pasteurized milk temporary storage tank;

[0013] 200 Membrane filtration system, 202 Ultrafiltration separator, 204 First retention solution temporary storage tank, 206 First permeate temporary storage tank, 208 Nanofiltration separator, 210 Second retention solution temporary storage tank, 212 Second permeate temporary storage tank, 214 Reverse osmosis filter, 216 Third retention solution temporary storage tank, 218 Third permeate temporary storage tank, 220 First dilution branch, 222 Second dilution branch, 224 Third dilution branch;

[0014] 300 Sterilization and preparation system, 302 Standard solution preparation tank, 304 Lactose hydrolysis tank, 306 Nutrient addition tank, 308 First sterilizer, 310 Homogenizer, 312 Aseptic storage tank.

[0015] 400 Nitrogen protection system, 402 Air compressor, 404 Nitrogen generator, 406 Nitrogen storage tank, 408 Nitrogen purging device, 410 First nitrogen pipeline, 412 Second nitrogen pipeline, 414 Third nitrogen pipeline;

[0016] 500 filling machine. Detailed Implementation

[0017] The principles and features of this application are described below with reference to the accompanying drawings. The examples given are only for explaining this application and are not intended to limit the scope of this application.

[0018] like Figure 1 As shown in the figure, this application provides a lactose-free liquid milk production line, including: a raw milk system 100, a membrane filtration system 200, and a blending and sterilization system 300.

[0019] The raw milk system 100 is equipped with a raw milk outlet. The raw milk outlet is configured to output pre-treated raw milk (e.g., raw milk that has undergone one or more pre-treatment processes such as milk purification, pasteurization, and defatting). The pre-treatment process can take place within the raw milk system 100, in which case the raw milk system 100 includes corresponding pre-treatment equipment (e.g., milk purifier, pasteurizer, defatting machine, etc.). Alternatively, the pre-treatment process can also take place on the upstream manufacturer's production line, in which case the raw milk system 100 may not include corresponding pre-treatment equipment.

[0020] The membrane filtration system 200 includes an ultrafiltration separator 202, a nanofiltration separator 208, a reverse osmosis filter 214, and a dilution pipeline.

[0021] An ultrafiltration (UF) separator has a first feed inlet, a first retention liquid outlet, and a first permeate outlet. The ultrafiltration separator 202 can separate most of the protein from the raw milk, obtaining a concentrated protein solution, which is output through the first retention liquid outlet. Therefore, the first retention liquid (also called UF retention liquid) output from the first retention liquid outlet is the ultrafiltration concentrated protein solution. The first permeate outlet outputs the first permeate (also called UF permeate).

[0022] The nanofiltration (NF) separator has a second feed inlet and a second permeate outlet. The nanofiltration separator 208 can separate most of the lactose from the first permeate to obtain a concentrated lactose solution, and the second permeate (also called NF permeate) is output through the second permeate outlet.

[0023] The reverse osmosis (RO) filter has a third feed inlet, a third retainer outlet, and a third permeate outlet. The blending and sterilization system 300 has a fourth feed inlet. The reverse osmosis filter 214 can separate most of the salt ions from the second permeate, obtaining a concentrated salt ion solution, which is output through the third retainer outlet. Therefore, the third retainer outlet output the third retainer (also called RO retainer or RO concentrate), which is a concentrated salt ion solution. The third permeate outlet outputs the third permeate (also called RO permeate), which is pure water.

[0024] The raw milk outlet is connected to the first inlet (via pipeline) and is configured to supply raw milk (e.g., pre-pasteurized milk) to the ultrafiltration separator 202. The first permeate outlet is connected to the second inlet (via pipeline) and is configured to supply the first permeate to the nanofiltration separator 208. The second permeate outlet is connected to the third inlet (via pipeline) and is configured to supply the second permeate to the reverse osmosis filter 214. Both the first and third retainer outlets are connected to the fourth inlet (via pipeline) and are configured to supply the first and third retainers to the blending and sterilization system 300.

[0025] The third permeate outlet is connected to a dilution pipeline, which is configured to dilute the liquid entering the ultrafiltration separator 202 and / or nanofiltration separator 208.

[0026] The lactose-free liquid milk production line provided in this application uses membrane filtration technology to remove most of the lactose from the raw milk, thereby reducing the carbohydrate content of the fresh milk. This results in a low GI (Glycemic Index), which is beneficial for meeting the nutritional needs of a wider range of consumers who require sugar control. Furthermore, most of the salt ions in the raw milk are concentrated by the reverse osmosis filter 214 and then transported to the blending and sterilization system 300, achieving salt ion recovery. This helps avoid the loss of large amounts of salt ions, thus preserving the taste and flavor of the fresh milk and improving its nutritional value. It also eliminates the need for additional salt ion supplements to enhance the taste and flavor of the fresh milk, simplifying the ingredient list and improving the product's market competitiveness.

[0027] In addition, the third permeate output from the reverse osmosis filter 214 is recycled back to the membrane filtration system 200 through a dilution pipe. This can dilute the liquid entering the ultrafiltration separator 202 and the nanofiltration separator 208, which helps to improve the working efficiency of the ultrafiltration separator 202 and the nanofiltration separator 208. Moreover, no additional diluent needs to be added, which also helps to simplify the ingredient list of fresh milk and improve the market competitiveness of the product.

[0028] In some exemplary embodiments, such as Figure 1 As shown, the membrane filtration system 200 also includes a first permeate storage tank 206. The inlet of the first permeate storage tank 206 is connected to the outlet of the first permeate, which can be achieved through a pipeline. The outlet of the first permeate storage tank 206 is connected to a second inlet, which can also be achieved through a pipeline. The dilution pipeline includes a first dilution branch 220, which is connected to the first permeate storage tank 206 to dilute the first permeate within the first permeate storage tank 206.

[0029] In this way, the first permeate can be effectively diluted before entering the nanofiltration separator 208, which is beneficial to improving the working efficiency of the nanofiltration separator 208, increasing the recovery rate of salt ion components, and reducing the carbohydrate content in fresh milk. In addition, the first permeate can be temporarily stored in the first permeate storage tank 206, which makes it easier to reasonably control the amount of liquid entering the nanofiltration separator 208 as needed.

[0030] In some exemplary embodiments (not shown in the figures), the dilution conduit includes a first dilution branch connected to a first feed inlet for diluting raw milk (such as prepasteurized milk) entering the ultrafiltration separator 202.

[0031] In this way, the raw milk can be diluted before passing through the ultrafiltration membrane, which helps to improve the working efficiency of the ultrafiltration separator 202 and improve the protein concentration rate.

[0032] In some exemplary embodiments, the nanofiltration separator 208 is provided with a second retention liquid outlet, and the second retention liquid (also called NF retention liquid) output from the second retention liquid outlet is lactose concentrate. The membrane filtration system 200 also includes a second retention liquid storage tank 210 connected to the second retention liquid outlet. For example... Figure 1 As shown, the dilution pipeline includes a second dilution branch 222 and a third dilution branch 224.

[0033] The third permeate outlet is connected to the second retention liquid storage tank 210 via the second dilution branch 222, configured to dilute the second retention liquid in the second retention liquid storage tank 210. The second retention liquid storage tank 210 is connected to the second feed inlet via the third dilution branch 224, configured to supply the diluted second retention liquid to the nanofiltration separator 208.

[0034] The second retention solution is diluted by the third permeate, which helps to improve the recovery rate of salt ions during membrane filtration. In addition, the second retention solution can be temporarily stored in the second retention solution storage tank 210, which facilitates reasonable control of the amount of liquid entering the nanofiltration separator 208.

[0035] Therefore, the lactose-free liquid milk production line provided in this application embodiment can use a dilution pipeline to dilute the raw milk (such as pasteurized milk) entering the ultrafiltration separator 202, and can also use a dilution pipeline to dilute the liquid (first permeate / second retention solution) entering the nanofiltration separator 208. These dilution methods can be set individually or together.

[0036] In some exemplary embodiments, such as Figure 1As shown, the membrane filtration system 200 also includes a third permeate storage tank 218 connected to the third permeate outlet, and the inlet end of the dilution pipe is connected to the third permeate storage tank 218. In this way, the third permeate can be temporarily stored in the third permeate storage tank 218, and the amount of liquid entering the dilution pipe can be reasonably controlled according to actual needs.

[0037] In some exemplary embodiments, the membrane filtration system 200 also includes a control valve (not shown) located in the dilution pipeline. The control valve is configured to control the on / off state and / or flow rate of the dilution pipeline to control the dilution ratio. This facilitates reasonable control of the dilution ratio to optimize the production efficiency of membrane filtration and monitor data on nutrient content at different stages.

[0038] In some exemplary embodiments, such as Figure 1 As shown, the membrane filtration system 200 also includes a second permeate storage tank 212. The inlet of the second permeate storage tank 212 is connected to the second permeate outlet via a pipeline. The outlet of the second permeate storage tank 212 is connected to a third inlet via a pipeline. The second permeate outlet is indirectly connected to the third inlet via the second permeate storage tank 212. In this way, the second permeate can be temporarily stored in the second permeate storage tank 212, facilitating the appropriate control of the liquid volume entering the reverse osmosis filter 214 as needed.

[0039] In some exemplary embodiments, such as Figure 1 As shown, the membrane filtration system 200 also includes a first retention liquid storage tank 204. The inlet of the first retention liquid storage tank 204 is connected to the first retention liquid outlet, which can be connected via a pipeline. The outlet of the first retention liquid storage tank 204 is connected to a fourth inlet, which can be connected via a pipeline. The first retention liquid outlet is indirectly connected to the fourth inlet through the first retention liquid storage tank 204.

[0040] In this way, the first retention solution can be temporarily stored in the first retention solution storage tank 204, which makes it convenient to reasonably control the amount of the first retention solution entering the preparation and sterilization system 300 as needed.

[0041] In some exemplary embodiments, such as Figure 1 As shown, the membrane filtration system 200 also includes a third retention liquid storage tank 216. The inlet of the third retention liquid storage tank 216 is connected to the third retention liquid outlet via a pipeline. The outlet of the third retention liquid storage tank 216 is connected to a fourth inlet via a pipeline. The third retention liquid outlet is indirectly connected to the fourth inlet via the third retention liquid storage tank 216.

[0042] In this way, the third retention solution can be temporarily stored in the third retention solution temporary storage tank 216, which makes it convenient to reasonably control the amount of the third retention solution entering the preparation and sterilization system 300 as needed.

[0043] In some exemplary embodiments, such as Figure 1 As shown, the preparation and sterilization system 300 includes a standard solution preparation tank 302, a lactose hydrolysis tank 304, a first sterilizer 308, and an aseptic storage tank 312. The first sterilizer 308 can be, but is not limited to, a steam immersion sterilizer. The standard solution preparation tank 302 is provided with a fourth inlet. The outlet of the first sterilizer 308 is connected to the aseptic storage tank 312 via a pipeline. The outlet of the aseptic storage tank 312 is configured to be connected to the filling machine 500 via a pipeline.

[0044] The outlet of the standard solution preparation tank 302 is connected to the inlet of the lactose hydrolysis tank 304 via a pipeline. The outlet of the lactose hydrolysis tank 304 is connected to the inlet of the first sterilizer 308 via a pipeline.

[0045] The first and third retention solutions are mixed according to the formula in the standard solution mixing tank 302 to form a standard solution, which then enters the lactose hydrolysis tank 304. Under the action of a trace amount of lactase, the remaining small amount of lactose is broken down, restoring the natural sweetness of the raw milk without making it overly sweet. The lactose-free fresh milk prepared in this way retains most of the nutrients of the raw milk, avoids the problem of large loss of salt ions caused by membrane filtration technology, and avoids the problem of excessive carbohydrate content caused by lactose hydrolysis technology, while also preserving the flavor and taste of the raw milk. Therefore, the liquid milk production line provided in this application embodiment can realize the mass industrial production of high-quality lactose-free fresh milk.

[0046] Alternatively, the inlet of the lactose hydrolysis tank 304 can be connected to the outlet of the first retention solution via a pipeline. The outlet of the lactose hydrolysis tank 304 can be connected to the fourth inlet via a pipeline. The outlet of the first retention solution is indirectly connected to the fourth inlet through the lactose hydrolysis tank 304.

[0047] Since the residual lactose is mainly present in the first retention solution, the lactose hydrolysis tank 304 can also be placed between the first retention solution storage tank 204 and the standard solution preparation tank 302. That is, the first retention solution is first hydrolyzed with lactose before entering the standard solution preparation tank 302 for preparation. This scheme does not depart from the design concept and purpose of this application and is also within the scope of protection of this application.

[0048] Furthermore, the first retention liquid outlet can be indirectly connected to the inlet of the lactose hydrolysis tank 304 via the first retention liquid storage tank 204. The third retention liquid outlet can be indirectly connected to the fourth inlet via the third retention liquid storage tank 216.

[0049] In some exemplary embodiments, such as Figure 1As shown, the blending and sterilization system 300 also includes a homogenizer 310. The inlet of the homogenizer 310 is connected to the outlet of the first sterilizer 308, and the outlet of the homogenizer 310 is connected to the inlet of the aseptic storage tank 312. The outlet of the first sterilizer 308 is indirectly connected to the aseptic storage tank 312 through the homogenizer 310. The homogenizer 310 can prevent fat aggregation and floating, thereby ensuring the uniformity and smoothness of the lactose-free liquid milk.

[0050] In some exemplary embodiments, such as Figure 1 As shown, the preparation and sterilization system 300 also includes a nutrient addition tank 306. The inlet of the nutrient addition tank 306 is connected to the outlet of the standard solution preparation tank 302, and can be connected via a pipeline or a lactose hydrolysis tank 304. The outlet of the nutrient addition tank 306 is connected to the inlet of the first sterilizer 308, and can be connected via a pipeline. The outlet of the lactose hydrolysis tank 304 or the outlet of the standard solution preparation tank 302 is indirectly connected to the inlet of the first sterilizer 308 via the nutrient addition tank 306. The nutrient addition tank 306 can be a high-speed shear mixing tank.

[0051] Nutrient addition tank 306 allows the addition of other nutritional supplements to fresh milk, creating different types of formula milk. For example, by adding calcium sources and stabilizers to nutrient addition tank 306, high-calcium milk with the desired content can be formulated.

[0052] Among them, such as Figure 1 As shown, when the lactose hydrolysis tank 304 is located downstream of the standard solution preparation tank 302, the inlet of the nutrient addition tank 306 is connected to the outlet of the lactose hydrolysis tank 304 via a pipeline. The outlet of the nutrient addition tank 306 is connected to the first sterilizer 308 via a pipeline. The outlet of the lactose hydrolysis tank 304 is indirectly connected to the inlet of the first sterilizer 308 via the nutrient addition tank 306.

[0053] When the lactose hydrolysis tank 304 is located upstream of the standard solution preparation tank 302, the inlet of the nutrient addition tank 306 is connected to the outlet of the standard solution preparation tank 302 via a pipeline. The outlet of the nutrient addition tank 306 is connected to the first sterilizer 308 via a pipeline. The outlet of the standard solution preparation tank 302 is indirectly connected to the inlet of the first sterilizer 308 via the nutrient addition tank 306.

[0054] In some exemplary embodiments, such as Figure 1As shown, the raw milk system 100 includes a raw milk storage tank 102. The raw milk storage tank 102 can store pre-treated raw milk, such as pasteurized milk, skim milk / low-fat milk, etc. The outlet of the raw milk storage tank 102 is the raw milk outlet, which can be directly transported to the ultrafiltration separator 202 through the pipeline.

[0055] Alternatively, the raw milk storage tank 102 may store raw milk that has not undergone pretreatment and requires one or more pretreatment processes such as milk purification, pasteurization, and defatting. In this case, the raw milk system 100 may also be called a raw milk pretreatment system, which includes the corresponding pretreatment equipment.

[0056] In some exemplary embodiments, such as Figure 1 As shown, the raw milk system 100 also includes a second sterilizer 108. The outlet of the raw milk storage tank 102 is connected to the inlet of the second sterilizer 108 via a pipeline. The second sterilizer 108 can be, but is not limited to, a pasteurizer. In this solution, the raw milk in the storage tank has not yet undergone sterilization. After being sterilized by the second sterilizer 108, it is then transported to the ultrafiltration separator 202 via a pipeline to prevent the raw milk from spoiling in the membrane filtration system 200.

[0057] The discharge port of the pasteurizer can form a pasteurized milk outlet. Alternatively, the discharge port of the pasteurizer can also be connected to the pasteurized milk storage tank 110, and the discharge port of the pasteurized milk storage tank 110 can form a pasteurized milk outlet. This makes it easier to reasonably control the amount of pasteurized milk entering the ultrafiltration separator 202 as needed.

[0058] In some exemplary embodiments, such as Figure 1 As shown, the raw milk system 100 also includes a milk purifier 104. The outlet of the raw milk storage tank 102 is connected to the inlet of the milk purifier 104 via a pipe. The outlet of the milk purifier 104 is connected to the inlet of the second sterilizer 108 via a pipe. The outlet of the raw milk storage tank 102 is indirectly connected to the inlet of the second sterilizer 108 via the milk purifier 104. The milk purifier 104 removes impurities from the raw milk and reduces the number of microorganisms.

[0059] A milk purifier 104 and a second sterilizer 108 can be connected to a milk purifier storage tank 106, where the milk purifier can be temporarily stored to facilitate reasonable control of the amount of liquid entering the second sterilizer 108.

[0060] In some exemplary embodiments, the raw milk system 100 also includes a defatting separator (not shown) connected to the outlet of the raw milk storage tank 102. The defatting separator (or simply defatting machine) is connected to the second sterilizer 108 and is located upstream or downstream of the second sterilizer 108.

[0061] A defatting machine can remove or reduce the fat in raw milk, resulting in lactose-free skim milk / lactose-free low-fat milk. The defatting process can proceed either before or after sterilization, meaning the defatting machine can be located upstream or downstream of the second sterilizer 108.

[0062] In some exemplary embodiments, the sterilization system 300 includes an aseptic storage tank 312, the outlet of which is configured to communicate with the filling machine 500.

[0063] like Figure 1 As shown, the lactose-free liquid milk production line also includes a nitrogen protection system 400. The nitrogen protection system 400 includes an air compressor 402, a nitrogen generator 404, a nitrogen storage tank 406, and a first nitrogen pipeline 410. The nitrogen storage tank 406 is provided with a first air outlet, and the aseptic storage tank 312 is provided with an air inlet. The air outlet of the air compressor 402 is connected to the air inlet of the nitrogen generator 404, and the air outlet of the nitrogen generator 404 is connected to the air inlet of the nitrogen storage tank 406. The first air outlet and the air inlet are connected through the first nitrogen pipeline 410.

[0064] In some embodiments, such as Figure 1 As shown, the nitrogen protection system 400 also includes a second nitrogen pipeline 412, and the nitrogen storage tank 406 is also provided with a second outlet. The second outlet is connected to the inlet of the second nitrogen pipeline 412, and the outlet of the second nitrogen pipeline 412 is aligned with the feed inlet of the filling machine 500.

[0065] In some embodiments, such as Figure 1 As shown, the nitrogen protection system 400 also includes a third nitrogen pipeline 414, and the nitrogen storage tank 406 is also provided with a third outlet. The third outlet of the nitrogen storage tank 406 is connected to the inlet of the third nitrogen pipeline 414, and the outlet of the third nitrogen pipeline 414 is aligned with the feed inlet of the filling machine 500.

[0066] In some embodiments, such as Figure 1 As shown, the nitrogen protection system 400 also includes a nitrogen purging device 408, which is located in the third nitrogen pipeline 414.

[0067] In some embodiments, the nitrogen purging device 408 has an air inlet at the bottom and an air jet outlet at the top; the air inlet faces the nitrogen storage tank 406, and the air jet outlet faces the filling machine 500.

[0068] The lactose-free liquid milk production line provided in this application embodiment adopts a nitrogen protection system 400. Through a first nitrogen pipeline 410 connected to the air inlet of the aseptic storage tank 312, through a second nitrogen pipeline 412 aligned with the feed inlet of the filling machine 500, and by using a nitrogen purging device 408, residual oxygen in the headspace of the liquid milk can be discharged, reducing product oxidation during the liquid milk processing and effectively extending the shelf life of the lactose-free liquid milk.

[0069] The following describes some examples and comparative examples of lactose-free milk preparations, and provides a comparison.

[0070] Example 1

[0071] In this embodiment, the protein content of the raw milk is 3.22%, the ash content is 0.67%, and during the production of the finished milk, the amount of lactase added is 0.03% of the weight of the standard solution, the enzyme activity is ≥4000 NLU, the hydrolysis time is 90 min, and the hydrolysis temperature is 40±5℃.

[0072] Raw milk is pasteurized and then passed through a UF membrane (molecular weight cutoff 20,000 Daltons). The RO permeate and UF permeate are mixed and diluted at a 1:1 ratio. The diluted solution is then passed through an NF membrane (2 nm pore size), and the NF permeate is passed through an RO membrane (0.2 nm pore size) to obtain RO concentrate. The RO concentrate, UF retention solution, and lactase are mixed and hydrolyzed to obtain raw milk with a protein content of 3.4% and a lactose content of less than 0.5 g / 100 g. The raw milk is then pasteurized with INF to obtain lactose-free milk.

[0073] Comparative Example 1

[0074] This comparative example provides a lactose-free process (method for producing lactose-free milk, H.H. Horst and K. Lawrence, WO2009 / 043356).

[0075] Step 1: Full-fat raw milk (protein content 3.31%, ash content 0.66%) is passed through an ultrafiltration (UF) membrane (molecular weight cutoff 20,000 Daltons) to obtain UF permeate and UF retention solution; the UF retention solution is stored for later use.

[0076] Step 2: Pass the UF permeate from Step 1 through a nanofiltration (NF) membrane (pore size 2nm) to obtain NF permeate and NF retention solution; the NF permeate is stored for later use.

[0077] Step 3: Mix the UF retention solution from Step 1 and the NF permeate solution from Step 2 to obtain a standard solution with some lactose removed. At this point, the lactose content of the standard solution is 3.00 g / 100 g.

[0078] Step 4: Add 0.03% by weight of standard solution lactase with an enzyme activity of ≥4000 NLU to hydrolyze residual lactose to a lactose concentration of ≤0.5 g / 100 mL, and obtain lactose-free raw milk.

[0079] Step 5: Standardize the lactose-free raw milk to a protein content of 3.40%.

[0080] Step 6: The lactose-free raw milk is sterilized with INF to obtain lactose-free milk.

[0081] Comparative Example 2

[0082] Milk fraction production and separation using forward osmosis, Shakeno Ulayman, Timothy P. Delman, Michael J. McCloskey, WO2020 / 009804.

[0083] Step 1: The raw milk (protein content of 3.31% and ash content of 0.67%) is defatted to obtain skim milk and light cream. The light cream is reserved for later use.

[0084] Step 2: The skim milk from Step 1 is passed through an ultrafiltration (UF) membrane (with a molecular weight cutoff of 20,000 Daltons) to obtain UF permeate and UF retention solution; the UF retention solution is stored for later use.

[0085] Step 3: The UF permeate from Step 2 is processed through a nanofiltration (NF) membrane (pore size of 2 nm) to separate the permeate and the retention solution; the NF permeate is retained for later use.

[0086] Step 4: Mix the light cream from Step 1, the NF permeate from Step 3, and the UF retention solution from Step 2 to obtain a standard solution with some lactose removed. The lactose content of the standard solution is 3.22g / 100ml.

[0087] Step 5: Add 0.03% by weight of standard solution lactase with an enzyme activity of ≥4000 NLU to hydrolyze residual lactose.

[0088] Step 6: Standardize the lactose-free raw milk to a protein content of 3.4%.

[0089] Step 7: The lactose-free raw milk is sterilized with INF to obtain lactose-free milk.

[0090] Comparative Example 3

[0091] Preparation of lactose-free dairy products, O. Tossian, J. Sachstan, WO2003 / 094623.

[0092] Step 1: Raw milk (protein content 3.28%, ash content 0.64%) is passed through an ultrafiltration (UF) membrane to obtain UF permeate and UF retention solution; the UF retention solution is stored for later use.

[0093] Step 2: Pass the UF permeate from Step 1 through a nanofiltration (NF) membrane to obtain NF permeate and NF retention solution.

[0094] Step 3: Pass the NF permeate from Step 2 through a reverse osmosis (RO) membrane to obtain RO permeate and RO concentrate.

[0095] Step 4: Mix the RO concentrate with the UF retention solution to obtain a standard solution with some lactose removed.

[0096] Step 5: Add 0.03% by weight of standard solution lactase with an enzyme activity of ≥4000 NLU to hydrolyze residual lactose.

[0097] Step 6: Add 18% water by weight of the standard solution to the lactose-free raw milk to standardize it to a protein content of 3.4%.

[0098] Step 7: The lactose-free raw milk is sterilized with INF to obtain lactose-free milk.

[0099] Table 1: Ash recovery rate of lactose-free milk

[0100]

[0101] Table 1 shows the ash recovery results for each comparative example and Example 1. The results show that the ash recovery rate of the embodiment of this application is the highest, approaching 90%. This application represents a significant breakthrough in this field.

[0102] Table 2: Sensory Comparison of Lactose-Free Milk in Comparative Examples

[0103]

[0104] The results in Table 2 show that the embodiment of this application scored the highest in overall preference, and also scored the highest in milk aroma, milk sweetness and thickness. After improving the ash recovery rate, the taste of lactose-free milk in the embodiment of this application was also improved.

[0105] Example 2

[0106] In this embodiment, the protein content of the raw milk is 3.27%, the ash content is 0.65%, and during the production of the finished milk, the amount of lactase added is 0.03% of the weight of the standard solution, the hydrolysis time is 90 min, and the hydrolysis temperature is 40±5℃.

[0107] Raw milk is passed through a UF membrane (molecular weight cutoff of 20,000 Daltons). The RO permeate is mixed and diluted with the UF permeate at a ratio of 0.25:1. The diluted solution is then passed through an NF membrane (pore size of 2 nm), and the NF permeate is passed through an RO membrane (pore size of 0.2 nm) to obtain RO concentrate. The RO concentrate, UF retention solution, and lactase are mixed and hydrolyzed to obtain raw milk with a protein content of 3.4% and a lactose content of less than 0.5 g / 100 g. The raw milk is then sterilized with INF to obtain lactose-free milk.

[0108] This embodiment changes the dilution ratio of RO permeate to UF permeate in Example 1.

[0109] Example 3

[0110] In this embodiment, the protein content of the raw milk is 3.21%, the ash content is 0.63%, and during the production of the finished milk, the amount of lactase added is 0.03% of the weight of the standard solution, the hydrolysis time is 90 min, and the hydrolysis temperature is 40±5℃.

[0111] Raw milk is passed through a UF membrane (molecular weight cutoff of 20,000 Daltons). The RO permeate is mixed and diluted with the UF permeate at a ratio of 0.5:1. The diluted solution is then passed through an NF membrane (pore size of 2 nm), and the NF permeate is passed through an RO membrane (pore size of 0.2 nm) to obtain RO concentrate. The RO concentrate, UF retention solution, and lactase are mixed and hydrolyzed to obtain raw milk with a protein content of 3.4% and a lactose content below 0.05%. The raw milk is then sterilized with INF to obtain lactose-free milk.

[0112] This embodiment changes the dilution ratio of RO permeate to UF permeate in Example 1.

[0113] Example 4

[0114] In this embodiment, the protein content of the raw milk is 3.27%, the ash content is 0.65%, and during the production of the finished milk, the amount of lactase added is 0.03% of the weight of the standard solution, the hydrolysis time is 90 min, and the hydrolysis temperature is 40±5℃.

[0115] Raw milk is passed through a UF membrane (molecular weight cutoff of 20,000 Daltons). The RO permeate is mixed and diluted with the UF permeate at a ratio of 0.75:1. The diluted solution is then passed through an NF membrane (pore size of 2 nm), and the NF permeate is passed through an RO membrane (pore size of 0.2 nm) to obtain RO concentrate. The RO concentrate, UF retention solution, and lactase are mixed and hydrolyzed to obtain raw milk with a protein content of 3.4% and a lactose content below 0.05%. The raw milk is then sterilized with INF to obtain lactose-free milk.

[0116] This embodiment changes the dilution ratio of RO permeate to UF permeate in Example 1.

[0117] Example 5

[0118] In this embodiment, the protein content of the raw milk is 3.28%, the ash content is 0.59%, and during the production of the finished milk, the amount of lactase added is 0.03% of the weight of the standard solution, the hydrolysis time is 90 min, and the hydrolysis temperature is 40±5℃.

[0119] Raw milk is passed through a UF membrane (molecular weight cutoff of 20,000 Daltons). The RO permeate is diluted with the UF permeate at a ratio of 2:1. The diluted solution is then passed through an NF membrane (pore size of 2 nm), and the NF permeate is passed through an RO membrane (pore size of 0.2 nm) to obtain RO concentrate. The RO concentrate, UF retention solution, and lactase are mixed and hydrolyzed to obtain raw milk with a protein content of 3.4% and a lactose content below 0.05%. The raw milk is then sterilized with INF to obtain lactose-free milk.

[0120] This embodiment changes the dilution ratio of RO permeate to UF permeate in Example 1.

[0121] Example 6

[0122] In this embodiment, the protein content of the raw milk is 3.25%, the ash content is 0.60%, and during the production of the finished milk, the amount of lactase added is 0.03% of the weight of the standard solution (RO concentrate and UF retention solution), the hydrolysis time is 90 min, and the hydrolysis temperature is 40±5℃.

[0123] Raw milk is passed through a UF membrane, and the UF permeate is passed through an NF membrane (molecular weight cutoff of 20,000 Daltons). The RO permeate and NF retention solution are mixed and diluted at a ratio of 1:1. The diluted solution is then passed through an NF membrane (pore size of 2 nm), and the NF permeate is passed through an RO membrane (pore size of 0.2 nm) to obtain RO concentrate. The RO concentrate, UF retention solution, and lactase are mixed and hydrolyzed to obtain raw milk with a protein content of 3.4% and a lactose content of less than 0.5 g / 100 g. The raw milk is then sterilized with INF to obtain lactose-free milk.

[0124] This embodiment modifies the dilution process of the RO permeate in Example 1.

[0125] Example 7

[0126] In this embodiment, the protein content of the raw milk is 3.28%, the ash content is 0.65%, and during the production of the finished milk, the amount of lactase added is 0.03% of the weight of the standard solution (RO concentrate and UF retention solution), the hydrolysis time is 90 min, and the hydrolysis temperature is 40±5℃.

[0127] Raw milk is diluted with RO permeate at a ratio of 1:1 before passing through a UF membrane (molecular weight cutoff of 20,000 Daltons). The UF permeate is then passed through an NF membrane (pore size of 2 nm), and the NF permeate is passed through an RO membrane (pore size of 0.2 nm) to obtain RO concentrate. The RO concentrate, UF retention solution, and lactase are mixed and hydrolyzed to obtain raw milk with a protein content of 3.4% and a lactose content of less than 0.5 g / 100 g. The raw milk is then sterilized with INF to obtain lactose-free milk.

[0128] This embodiment modifies the dilution process of the RO permeate in Example 1.

[0129] Example 8

[0130] In this embodiment, the protein content of the raw milk is 3.22%, the ash content is 0.67%, and during the production of the finished milk, the amount of lactase added is 0.06% of the weight of the UF retention solution, the enzyme activity is ≥4000 NLU, the hydrolysis time is 90 min, and the hydrolysis temperature is 40±5℃.

[0131] Raw milk is pasteurized and then passed through a UF membrane (molecular weight cutoff 20,000 Daltons). The UF retention solution is mixed with lactase for hydrolysis, yielding concentrated milk with a lactose content below 0.05%. The RO permeate is diluted with the UF permeate at a 1:1 ratio. The diluted solution is then passed through an NF membrane (2 nm pore size), and the NF permeate is passed through an RO membrane (0.2 nm pore size) to obtain RO concentrate. The RO concentrate is mixed with the concentrated milk to obtain raw milk with a protein content of 3.4% and a lactose content below 0.05%. This raw milk is then pasteurized with INF to obtain lactose-free milk.

[0132] This embodiment modifies the lactase addition process in Example 1.

[0133] Table 3: Ash recovery rate and salt ion concentration of lactose-free milk

[0134]

[0135] Table 3 shows the ash recovery and salt ion concentration of each embodiment. The results show that the ash recovery rates of Examples 1, 5, and 8 all reached over 90%, higher than the other five examples. In Example 5, the RO permeate was diluted twice as much as in Example 1, but the ash recovery rates were essentially the same, indicating that the dilution ratio in Example 1 was the optimal one.

[0136] Table 4: Sensory Comparison of Lactose-Free Milk from Various Examples

[0137]

[0138] Table 4 shows the sensory scores of lactose-free milk in each embodiment. The results show that when the ash recovery rate of Examples 1, 5, 6, and 7 reached over 85%, the overall preference score was above 7.00. Therefore, in this embodiment, when the ash recovery rate reaches over 85%, the taste of lactose-free milk is significantly improved. It can be seen that the lactose-free liquid milk production line provided in this embodiment has achieved a significant breakthrough in salt ion recovery, and no lactose was detected (lactose content ≤0.5g / 100g can be considered lactose-free), with a glycemic index (GI) value ≤55, meeting the national standards for zero lactose and low GI. It can be promoted and applied in the current market to achieve the mass industrial production of low-GI, lactose-free fresh milk.

[0139] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0140] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0141] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0142] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0143] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0144] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A lactose-free liquid milk production line, characterized in that, include: Raw milk system, membrane filtration system, blending and sterilization system; The raw milk system has a raw milk outlet; the membrane filtration system includes an ultrafiltration separator, a nanofiltration separator, a reverse osmosis filter, and a dilution pipeline; the ultrafiltration separator has a first feed inlet, a first retention liquid outlet, and a first permeate outlet; the nanofiltration separator has a second feed inlet and a second permeate outlet; the reverse osmosis filter has a third feed inlet, a third retention liquid outlet, and a third permeate outlet; the blending and sterilization system has a fourth feed inlet. The raw milk outlet is connected to the first inlet and is configured to supply raw milk to the ultrafiltration separator; the first permeate outlet is connected to the second inlet and is configured to supply the first permeate to the nanofiltration separator; the second permeate outlet is connected to the third inlet and is configured to supply the second permeate to the reverse osmosis filter; the first retention liquid outlet and the third retention liquid outlet are both connected to the fourth inlet and are configured to supply the first retention liquid and the third retention liquid to the blending and sterilization system; the third permeate outlet is connected to the dilution pipe, which is configured to dilute the liquid entering the ultrafiltration separator and / or the nanofiltration separator.

2. The lactose-free liquid milk production line according to claim 1, characterized in that, The membrane filtration system further includes a first permeate storage tank, the inlet of which is connected to the first permeate outlet, and the outlet of which is connected to the second inlet. The dilution pipeline includes a first dilution branch, which is connected to the first permeate storage tank to dilute the first permeate in the first permeate storage tank.

3. The lactose-free liquid milk production line according to claim 1, characterized in that, The dilution pipeline includes a first dilution branch connected to the first feed inlet to dilute the raw milk entering the ultrafiltration separator.

4. The lactose-free liquid milk production line according to any one of claims 1 to 3, characterized in that, The nanofiltration separator is provided with a second retention liquid outlet, and the membrane filtration system further includes a second retention liquid storage tank connected to the second retention liquid outlet; the dilution pipeline includes a second dilution branch and a third dilution branch. The third permeate outlet is connected to the second retention liquid storage tank through the second dilution branch, and is configured to dilute the second retention liquid in the second retention liquid storage tank; The second retention liquid temporary storage tank is connected to the second feed port through the third dilution branch, and is configured to deliver the diluted second retention liquid to the nanofiltration separator.

5. The lactose-free liquid milk production line according to any one of claims 1 to 3, characterized in that, The membrane filtration system further includes a third permeate storage tank connected to the third permeate outlet, and the inlet end of the dilution pipe is connected to the third permeate storage tank; and / or The membrane filtration system further includes a control valve located in the dilution pipeline, the control valve being configured to control the on / off state and / or flow rate of the dilution pipeline to control the dilution ratio.

6. The lactose-free liquid milk production line according to any one of claims 1 to 3, characterized in that, The membrane filtration system further includes a second permeate storage tank; the inlet of the second permeate storage tank is connected to the second permeate outlet, the outlet of the second permeate storage tank is connected to the third inlet, and the second permeate outlet is indirectly connected to the third inlet through the second permeate storage tank; The membrane filtration system further includes a first retention liquid storage tank; the inlet of the first retention liquid storage tank is connected to the first retention liquid outlet, and the outlet of the first retention liquid storage tank is connected to the fourth inlet; the first retention liquid outlet is indirectly connected to the fourth inlet through the first retention liquid storage tank. The membrane filtration system further includes a third retention liquid storage tank; the inlet of the third retention liquid storage tank is connected to the outlet of the third retention liquid, and the outlet of the third retention liquid storage tank is connected to the fourth inlet; the outlet of the third retention liquid is indirectly connected to the fourth inlet through the third retention liquid storage tank.

7. The lactose-free liquid milk production line according to any one of claims 1 to 3, characterized in that, The preparation and sterilization system includes a standard solution preparation tank, a lactose hydrolysis tank, a first sterilizer, and a sterile storage tank. The outlet of the sterile storage tank is configured to be connected to the filling machine. The standard solution preparation tank is provided with the fourth inlet, and the outlet of the first sterilizer is connected to the sterile storage tank. Wherein, the outlet of the standard solution preparation tank is connected to the inlet of the lactose hydrolysis tank, and the outlet of the lactose hydrolysis tank is connected to the inlet of the first sterilizer; or The inlet of the lactose hydrolysis tank is connected to the outlet of the first retention liquid, and the outlet of the lactose hydrolysis tank is connected to the fourth inlet. The outlet of the first retention liquid is indirectly connected to the fourth inlet through the lactose hydrolysis tank. The outlet of the standard solution preparation tank is connected to the inlet of the first sterilizer.

8. The lactose-free liquid milk production line according to claim 7, characterized in that, The preparation and sterilization system further includes a nutrient addition tank, the inlet of which is connected to the outlet of the standard solution preparation tank, and the outlet of which is connected to the inlet of the first sterilizer. The outlet of the lactose hydrolysis tank or the outlet of the standard solution preparation tank is indirectly connected to the inlet of the first sterilizer via the nutrient addition tank; and / or The blending and sterilization system also includes a homogenizer, the inlet of which is connected to the outlet of the first sterilizer, the outlet of which is connected to the inlet of the aseptic storage tank, and the outlet of the first sterilizer is indirectly connected to the aseptic storage tank through the homogenizer.

9. The lactose-free liquid milk production line according to any one of claims 1 to 3, characterized in that, The raw milk system includes raw milk storage tanks; The raw milk system also includes a second sterilizer, and the outlet of the raw milk storage tank is connected to the inlet of the second sterilizer.

10. The liquid milk production line according to claim 9, characterized in that, The raw milk system also includes a milk purifier, wherein the outlet of the raw milk storage tank is connected to the inlet of the milk purifier, the outlet of the milk purifier is connected to the inlet of the second sterilizer, and the outlet of the raw milk storage tank is indirectly connected to the inlet of the milk purifier and the second sterilizer; and / or The raw milk system also includes a defatting machine connected to the outlet of the raw milk storage tank; the defatting machine is connected to the second sterilizer and is located upstream or downstream of the second sterilizer.

11. The lactose-free liquid milk production line according to any one of claims 1 to 3, characterized in that, The blending and sterilization system includes a sterile storage tank, and the outlet of the sterile storage tank is configured to be connected to the filling machine. The lactose-free liquid milk production line also includes a nitrogen protection system, which includes an air compressor, a nitrogen generator, a nitrogen storage tank, and a first nitrogen pipeline. The nitrogen storage tank is provided with a first air outlet, and the aseptic storage tank is provided with an air inlet. The air outlet of the air compressor is connected to the air inlet of the nitrogen generator, and the air outlet of the nitrogen generator is connected to the air inlet of the nitrogen storage tank. The first air outlet and the air inlet are connected through the first nitrogen pipeline.

12. The lactose-free liquid milk production line according to claim 11, characterized in that, The nitrogen protection system also includes a second nitrogen pipeline, and the nitrogen storage tank is also provided with a second outlet. The second outlet is connected to the inlet of the second nitrogen pipeline, and the outlet of the second nitrogen pipeline is aligned with the feed inlet of the filling machine. The nitrogen protection system also includes a third nitrogen pipeline, and the nitrogen storage tank is also provided with a third outlet. The third outlet of the nitrogen storage tank is connected to the inlet of the third nitrogen pipeline, and the outlet of the third nitrogen pipeline is aligned with the feed inlet of the filling machine. The nitrogen protection system also includes a nitrogen purging device, which is located in the third nitrogen pipeline; The nitrogen purging device has an inflation port at the bottom and an air jet port at the top; the inflation port faces the nitrogen storage tank and the air jet port faces the filling machine.

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