CN103504454A - Food dipping method based on strong electrolyte ion current controlled by function signal - Google Patents

Abstract

The invention relates to a food dipping processing method based on a strong electrolyte ion current controlled by a function signal, which belongs to the technical field of food processing using electromagnetics. The components include (A) drive unit: arbitrary function signal generator, power amplifier; (B) induction unit: annular silicon steel core, silicone tube winding, copper coil winding; (C) impregnation unit: impregnation tank, vacuum pump. A specific periodic function signal is generated by a function signal generator, and after being amplified by a power amplifier, the copper coil winding at one end is excited, and a changing magnetic flux is generated in the annular silicon steel core, which triggers the silicon tube winding filled with a strong electrolyte solution at the other end Induced electromotive force is generated. Driven by the induced electromotive force, the positive and negative ions in the solution circuit system move in a directional manner to complete the impregnation treatment of food. The impregnation solution must be an ionic compound with a strong electrolyte. The invention avoids the electrolysis of the immersion solution and the corrosion and fouling of the polar plate brought about by the electrochemical reaction, and the principle is different from the electrolysis, electrophoresis, electrodialysis and electroplating technologies.

Description

A food dipping and processing method based on strong electrolyte ion current controlled by function signal

technical field

A food dipping processing method based on a strong electrolyte ion current controlled by a function signal. The invention relates to a novel food dipping processing method, which is suitable for strong electrolyte dipping liquids and belongs to the technical field of food processing using electromagnetics. Compared with the vacuum impregnation technique, the invention can complete the impregnation treatment of food raw materials in a shorter time. Wet brining, coloring treatments and enhancement of trace mineral elements can be accomplished. the

Background technique

The traditional Chinese dipping food processing methods include five categories, namely salting, vinegar pickling, bad pickling, sauce pickling and sugar pickling. There are many kinds of dipped foods, among which the well-known products include all kinds of kimchi, pickles, sour pickled ginger slices, seasoned fragrant melon seeds, salted eggs, chicken feet and pig skin with pickled peppers, drunk crabs, etc., which are all favored by people. The purpose of impregnation treatment is to infiltrate various solute ions and molecules in the impregnation solution, such as hydrogen, sodium, potassium, calcium, iron, selenium, chloride ions, sucrose, and small alcohol molecules into the gaps of food tissues and cells. Part of the water in the food is removed by the pressure difference, resulting in a good flavor. During this process, the solute diffusion rate in the soaking solution is affected by the partial pressure difference of various substances inside and outside the tissue cells, soaking temperature, environmental pressure and the porosity of food raw materials. In dipped food, especially aquatic products marinated by wet method, because the solute diffusion rate is slow and long-term dipping will cause deterioration, it is generally pickled in a refrigerated environment at 5°C, which inevitably results in soluble protein and vitamins due to long time. , loss of minerals and pigments. In order to speed up the immersion treatment of food, it is usually only carried out by increasing the immersion temperature, increasing the solute concentration and changing the ambient atmospheric pressure. However, because high temperature can cause fermentation and rancidity of dipped food, the method of accelerating the dipping process by increasing the temperature is rarely used in industry. Increasing the solute concentration of the impregnating solution will result in the formation of "high salt" products, and it is necessary to increase the desalination process operation in the later stage. At present, the only mature and applied technology that can speed up food dipping treatment is vacuum impregnation technology (Vacuum Impregnation referred to as VI). The core principle is to use the hydrodynamic mechanism and deformation relaxation phenomenon caused by pressure difference to improve pickling efficiency. There are pores in the cells of food tissue. Under vacuum, low-pressure air bubbles are formed inside the material, which also causes the intercellular distance to increase and the material to expand. The external liquid is more likely to penetrate under the pressure difference between the inside and outside of the cells and the capillary effect. The impregnation treatment of food is usually completed within tens of minutes, which has greatly shortened the processing time compared with the days or dozens of days required for atmospheric pressure impregnation, so it can be widely used. the

Conductors of electric current are divided into two categories, the first category is metal conductors, and the current form is electronic current, and the second category is electrolytic solution or molten electrolyte. Electrolytes can be divided into strong electrolytes and weak electrolytes. Strong electrolytes can be completely ionized in solution, mostly ionic compounds and most salts, while weak electrolytes are incompletely ionized, mostly covalent compounds. The conductivity of the electrolyte solution is related to the degree of ionization, concentration, and temperature, and the current form is ionic current. Since the electrolyte solution contains a large number of positive and negative ions, directional migration will occur in an environment with a potential difference. The technical applications based on this principle include electrolysis, electroplating, electrophoresis and electrodialysis. They all cause directional movement of ions by generating a potential difference between electrodes. Among them, electrolysis, electroplating, and electrodialysis are mostly treated with positive and negative ions in the electrolyte, and their molecular weight is small; while electrophoresis targets some surfaces in the solution with a large number of positive and negative ions. Electronic macromolecules of proteins are processed. the

The induced ionic current is to introduce a changing magnetic flux into the solenoid filled with electrolyte to generate an induced electromotive force as a "source power" to drive the movement of ions in the solution loop system. In the solution circuit system, according to the change rate of the magnetic flux of the coil, the induced electromotive force has different rules, and then has different driving effects. This is because according to the movement of charged ions in the electric field, the force (F) that drives the charged ions is equal to the product of the net charge (Q) carried by the ions and the electric field strength (X), that is, F=QX. Due to the different rates of change of the magnetic flux, the peak values of the generated alternating induced electromotive force in the positive and negative directions are different, that is, the magnitude and duration of the electric field force received by the ions in different directions are different. The forward movement of ions is also affected by resistance ( f ). For a similar spherical ion, it obeys Stokes' law, that is: f = 6π r η ν (r is the radius of the ion particle, η is the viscosity of the solution medium Coefficient, ν is the moving speed of ions), when the balance is reached, the charged ions move at a uniform speed, that is, F = f .

Contents of the invention

The purpose of the present invention is to provide a food dipping processing method based on a strong electrolyte ion current controlled by a function signal, which relates to a new type of food dipping processing method. The current amplifies and excites the coil winding at one end of the mutual inductance silicon steel core, and the changing magnetic flux generates a correspondingly changing induced electromotive force in the spiral silicone tube winding pipeline filled with strong electrolyte solution as the "source power" to drive the conduction loop. ions and form directional migration. Due to the different changes in the induced electromotive force, the magnitude and duration of the "positive" and "negative" electric field forces on the ions are different, so that the ions have different stepping effects. According to the ionic characteristics of the solution system, select the appropriate function waveform to achieve the best impregnation effect. The technical principle is shown in Figure 1, and the waveform example is shown in Figure 2. the

The technical solution of the present invention: a food dipping and processing method based on a strong electrolyte ion current controlled by a function signal. The components of the device of the present invention include (A) a drive unit: including an arbitrary function signal generator (1), a power amplifier (2 ); the arbitrary function signal generator (1) is connected with the power amplifier (2); (B) induction unit: including annular silicon steel core (3), silicone tube winding (4), copper coil winding (5); annular silicon steel One end of the iron core (3) is wound with a copper coil winding (5), and the other end of the annular silicon steel core (3) is wound with a silicone tube winding (4); the copper coil winding (5) is connected to the power amplifier (2); the silicone tube The two ends of the winding (4) are respectively connected to the conduction ports at both ends of the dipping tank (6), so that the strong electrolyte solution forms a closed loop; (C) Impregnation unit: including dipping tank (6), vacuum pump (7), vacuum pump (7 ) is connected with the dipping tank (6);

A specific regular periodic signal is generated by a function generator, and the signal voltage is amplified by a power amplifier to excite the copper coil winding at one end of the annular silicon steel core. The distortion rate of the amplified voltage signal is ≦0.1%. The corresponding regularly changing induced electromotive force in the winding of the spiral silicone tube filled with strong electrolyte solution at the other end of the core is used as the "source power" to drive the directional migration of ions in the immersion liquid system; according to the ionic characteristics of the solution system, select a suitable periodic function waveform To achieve the best impregnation effect; when the periodic function waveform is issued, the conductivity of the strong electrolyte impregnation solution must be in the range of 20-60mS/cm, and the changing magnetic flux can generate 500mV-1.8V alternating current at both ends of the impregnation tank. Variable induction electromotive force, when the thickness of the food material is within 3cm, the impregnation can be completed within 5 minutes, that is, the volume concentration of the solute in the impregnation solution in the internal and external environment of the food material is basically the same.

The function signal generator in the drive unit generates any custom waveform signal with a frequency of 1Hz~100Hz. The signal has one rising edge and two falling edges in one cycle. The slope of the rising edge is greater than that of the falling edge. The width range is 10Vpp Within (±5V), the output impedance is 50Ω, the power amplifier used is compatible with the amplification of arbitrary function waveforms, the full power frequency range is 1Hz~100Hz, the output voltage width is 300Vpp (±150V), the output current is 0~40mA, and the input impedance is 50Ω. Excite the coil windings on one side of the rectangular silicon steel core. the

The annular silicon steel core in the induction unit is a silicon steel rectangular core, and the copper coil winding is a single-layer winding. The diameter of the copper wire ranges from 0.6 to 0.8mm, and the number of turns is 120 to 150 turns, which are connected to the power amplifier. the

Silicone tube winding filled with strong electrolyte impregnation solution is made of food-grade platinum silicone tube with good insulation, good flexibility, non-toxic and tasteless, the inner diameter ranges from 1 to 5mm, the tube wall thickness is 3mm, and the winding is a single-layer winding. The range is 10~20 circles. The two ends of the silicone tube are connected to and communicated with the conduction ports on both sides of the dipping tank respectively, so that the dipping liquid is in a circulating loop system. At 20-60mS/cm, an induced electromotive force of 500mV-1.8V can be generated at both ends of the dipping tank, which can produce directional driving effects on different ions in the dipping liquid, thereby completing the dipping treatment of food. The induced electromotive force can be detected by inserting platinum electrodes at both ends of the dipping tank and using an AC voltmeter. The size of the platinum electrodes is 5mm×5mm×0.15mm. the

The glass dipping tank in the dipping unit has a cylindrical structure with an inner diameter of 80mm, a length of 300mm, and a wall thickness of 3mm. There are valves for vacuuming and sealing covers for sample injection or sampling on the top. There are conduction ports in the middle of both sides of the dipping tank. It can be connected with a silicone tube so that the entire immersion liquid system forms a circulation loop, and the circulation of the immersion liquid system is controlled by a vacuum pump. the

Then the function signal generator generates a specific waveform periodic function signal with a frequency of 1Hz~100Hz. The signal has one rising edge and two falling edges in one cycle. The slope of the rising edge is greater than that of the falling edge. 10Vpp (±5V), output impedance 50Ω, the signal passes through a power amplifier with a full power frequency range of 1Hz~100Hz, an output voltage width of 300Vpp (±150V), an output current of 0~40mA, and an input impedance of 50Ω to amplify the voltage signal , to excite the coil winding on one side of the rectangular silicon steel core, the coil winding is a single-layer winding, the diameter of the copper wire is 0.6~0.8mm, and the number of turns is 120~150 turns. Therefore, there will be regularly changing magnetic flux in the silicone tube winding filled with strong electrolyte impregnation solution. The material of the silicone tube is a food-grade platinum silicone tube with good insulation, good flexibility, non-toxic and tasteless, and the inner diameter ranges from 1 to 5mm. The thickness of the tube wall is 3mm, and the winding is a single-layer winding, and the number of turns ranges from 10 to 20 turns. When the magnetic flux with specific regular changes is generated, when the conductivity of the immersion liquid is 20~60mS/cm, an induced electromotive force of 500mV~1.8V with specific regular changes can be generated at both ends of the immersion tank, which can generate orientation for different ions in the immersion liquid. Driving effect, so as to complete the impregnation treatment of food. The induced electromotive force can be detected by inserting a platinum electrode at the 2 ends of the dipping tank and detected by an AC voltmeter. The size of the platinum electrode is 5mm×5mm×0.15mm. the

Beneficial effects of the present invention: the impregnation process of food materials can be quickly completed, and the impregnation solution must belong to the ionic compound of strong electrolyte. For food materials that need to be treated by wet salting, coloring and mineral nutrient enhancement, when the thickness is less than 3cm, the impregnation can be completed within 5 minutes, that is, the volume concentration of solutes in the internal and external environment of the food material is basically the same after stabilization. When dipping, the solution concentration is 0.01%~6% and the conductivity is in the range of 20~60mS/cm. If the ion concentration is high, the induced ion current density is too high, which will cause convection or turbulence in the solution circuit system, which is not conducive to ion impregnation. Since the directional migration driving force of the electrolyte ions comes from the induced electromotive force rather than the direct insertion of the electrode plate, the present invention avoids the electrolysis of the impregnation solution and the corrosion and scaling of the plate due to the electrochemical reaction, and the principle is completely different from the current one. Electrolysis, electrophoresis, electrodialysis and electroplating techniques. the

Description of drawings

Fig. 1 Schematic diagram of a food dipping technology based on a strong electrolyte ion current controlled by a function signal. 1. Arbitrary function signal generator, 2. Power amplifier, 3. Annular silicon steel core, 4. Silicone tube winding, 5. Copper coil winding, 6. Dip tank, 7. Vacuum pump. the

Figure 2 Example diagram of magnetic flux change and induced electromotive force. the

Fig. 3 Function signal waveform diagram of salted greengage. the

Fig. 4 Observation of the microscopic salinity in the internal tissue of greengage after induced ion current treatment for 5 minutes. the

Fig. 5 Functional signal waveform diagram of calcium salt soaked apples. the

Figure 6 Microscopic calcium salt cloth observation of apple internal tissue after induced ion current treatment for 5 minutes. the

Fig. 7 Functional signal waveform diagram of melon seeds coloring and dipping. the

Detailed ways

Embodiment 1 Salted Greengage

Weigh 300 grams of greengage, wash and place in the dipping tank, the cavity size of the tank is 80mm in inner diameter, 300mm in length, and 3mm in wall thickness. Inject sodium chloride pickling solution with a mass fraction of 5% until the sample is submerged. At this time, the conductivity of the pickling solution measured by a Mettler-Toledo FE30 conductivity meter is 55mS/cm. After the immersion tank is sealed, turn on the vacuum pump to evacuate until the solution fills the silicone pipeline, and the immersion solution in the system is in a loop state. Among them, the material of the silicone tube is a food-grade platinum silicone tube with good insulation, good flexibility, non-toxic and tasteless, the inner diameter is 2mm, and the thickness of the tube wall is 3mm. The silicone tube is wound on one end of the rectangular silicon steel core, and the winding of the silicone tube is a single-layer winding. , the range of turns is 20 turns. Afterwards, the Puyuan DG1022 function signal generator generates a periodic function signal of a specific waveform. The signal has one rising edge and two falling edges within one cycle, and the slope of the rising edge is greater than that of the falling edge. The waveform diagram is shown in Figure 3 Shown, cycle 750ms, t ₀ =0s, t ₁ =100ms, t ₂ =250ms, t ₃ =400ms, t ₄ =500ms, t ₅ =650ms, t ₆ =750ms, V ₁ =2.5V, V ₂ =5V , the waveform width V _pp =5V, and the voltage signal is amplified 10 times by the American TEGAM brand power amplifier model 2350, so as to excite the coil winding at the other end of the rectangular silicon steel core. The coil winding is a single-layer winding, copper The diameter of the wire is 0.8mm, and the number of turns is 140. At this time, the induced electromotive force of the system is 1.2V. Take out the greengage after starting 5min, namely meet dipping requirement, at this moment the salt content of greengage is 4.6%, and the salt content of untreated greengage is 0.2%.

For the microscopic inspection of the salting effect, a scanning electron microscope was used to observe the salt distribution in the tissue near the core of the greengage. As shown in Figure 4, it can be seen that the internal tissue of the greengage contains obvious salt after 5 minutes of treatment. Detection method: Take greengage flesh close to the core, cut into rectangular blocks of 4mm × 1.5mm × 5mm, put it directly in liquid nitrogen and freeze (-210°C) for 5 minutes, take it out and break it brittle, and put it in a freeze dryer Rapid dehydration for 30 minutes in a -45°C cold trap and a vacuum of 12Pa. The surface of the dried sample was sprayed with gold and observed under a Quanta 200 scanning electron microscope in the Netherlands, as shown in Figure 4. the

Calcium nutrition fortification of embodiment 2 apples

Wash and peel the apples, cut them into 3×3×3cm blocks, weigh 400g, place them in a dipping tank, the cavity of the dipping tank has an inner diameter of 80mm, a length of 300mm, and a wall thickness of 3mm, and inject food with a mass fraction of 1000mg/kg Grade calcium lactate solution submerges the sample. At this time, the conductivity of the pickling solution measured by Mettler-Toledo FE30 conductivity meter is 22mS/cm. After sealing, turn on the vacuum pump to evacuate until the solution is filled with silica gel pipeline, and the solution in the system forms a loop. The silicone tube material is a food-grade platinum silicone tube with good insulation, good flexibility, non-toxic and tasteless, the inner diameter range is 4mm, the tube wall thickness is 3mm, the silicone tube is wound on one end of the rectangular silicon steel mutual induction core, and the silicone tube winding is a single Layer winding, the number of turns is 15 turns. A periodic function signal of a specific waveform is generated by the Puyuan DG1022 function signal generator. The signal has one rising edge and two falling edges within one cycle. The slope of the rising edge is greater than the slope of the falling edge. The waveform diagram is shown in Figure 5 , period 540ms, t ₀ =0s, t ₁ =50ms, t ₂ =100ms, t ₃ =220ms, t ₄ =300ms, t ₅ =420ms, t ₆ =540ms, V ₁ =4V, V ₂ =8V, its The waveform width Vpp=8V, the voltage signal is amplified 10 times by the American TEGAM brand power amplifier model 2350, and the coil winding at the other end of the rectangular iron core is excited. The coil winding is a single-layer winding, and the diameter of the copper wire is 0.8mm. , the number of turns is 150 circles, and the induced electromotive force of the solution system is 800mV at this time. Keep it for 5 minutes and take it out, and the apple pieces meet the requirements for dipping. At this time, the calcium content in the apple pulp is 0.1mg/g, while the calcium content before the treatment is 0.003mg/g.

For the microscopic examination of the effect of calcium element impregnation, a scanning electron microscope was used to observe the distribution of calcium salts in the internal tissues of the apple flesh. As shown in Figure 6, it can be seen that the internal tissues of the apples already contain obvious calcium salts after 5 minutes of treatment. Detection method: Take the inner pulp tissue of the apple, cut it into rectangular blocks of 4mm × 1.5mm × 5mm, directly place it in liquid nitrogen and freeze it (-210°C) for 5min, take it out and break it brittlely, and put it in a freeze dryer at -45 ℃ cold trap, vacuum 12Pa environment rapid dehydration 30min. The surface of the dried sample was sprayed with gold, and observed under the Quanta 200 scanning electron microscope in the Netherlands, as shown in Figure 6. the

Embodiment 3: melon seeds coloring

The synthetic pigment amaranth, molecular formula C ₂₀ H ₁₁ O ₁₀ N ₂ S ₃ Na ₃ , is a water-soluble pigment. This example is for the stable coloring of the plant fiber surface. Weigh 500 grams of sunflower seeds and put them in the dipping tank. The cavity of the dipping tank has an inner diameter of 80mm, a length of 300mm, and a wall thickness of 3mm. The amaranth dipping solution with a concentration of 40mg/kg is injected until the sample is immersed. At this time, a Mettler- The conductivity of the pickling solution measured by Toledo FE30 conductivity meter is 20mS/cm. After sealing, turn on the vacuum pump to evacuate until the solution is filled with the silicone tube, and the solution in the system forms a loop state. The silicone tube material is a food-grade platinum silicone tube with good insulation, good flexibility, non-toxic and tasteless, and the inner diameter range is 5mm. The thickness is 3mm, the silicone tube is wound on one end of the rectangular silicon steel core, and the winding of the silicone tube is a single-layer winding with 20 turns. A periodic function signal of a specific waveform is generated by the Puyuan DG1022 function signal generator. The signal has 1 rising edge and 2 falling edges in one cycle. The slope of the rising edge is greater than that of the falling edge. The waveform diagram is shown in Figure 7 , period 440ms, t ₀ =0s, t ₁ =80ms, t ₂ =120ms, t _{3 =240ms, t 4 =} 280ms, t ₅ =400ms, t ₆ =440ms, V ₁ =5V, V ₂ =10V, its The waveform width Vpp=10V, the voltage signal is amplified 10 times by the power amplifier of American TEGAM brand 2350, and then the coil winding at the other end of the rectangular silicon steel core is excited. The copper winding is a single-layer winding, and the diameter of the copper wire is 0.8mm, the number of turns is 140 turns, and the induced electromotive force of the solution system is 900mV at this time. Take it out after keeping it for 5 minutes. Through the sensory evaluation and comparison with the melon seeds soaked in normal pressure for the same time, the color of the melon seeds treated by this method is stable, and the color does not fade after washing. According to the OT-15 analysis method for the determination of the total content of pigment substances edited by Ling Guanting in the "Handbook of Food Additives (Third Edition)", the content of amaranth in the treated melon seed shells is 18 mg/kg, while the content of amaranth in the melon seed shells soaked at normal pressure for 5 minutes Red content is 5mg/kg.

Claims (5)

1. A food dipping and processing method based on a strong electrolyte ion current controlled by a function signal, characterized in that the device consists of (A) a drive unit: including an arbitrary function signal generator (1), a power amplifier (2); any The function signal generator (1) is connected with the power amplifier (2); (B) induction unit: including annular silicon steel core (3), silicon tube winding (4), copper coil winding (5); annular silicon steel core ( One end of 3) is wound with a copper coil winding (5), and the other end of the annular silicon steel core (3) is wound with a silicone tube winding (4); the copper coil winding (5) is connected to the power amplifier (2); the silicone tube winding (4 ) and the two ends of the impregnation tank (6) are respectively connected to the conduction ports at both ends, so that the strong electrolyte solution forms a closed loop; (C) impregnation unit: including the impregnation tank (6), vacuum pump (7), vacuum pump (7) and impregnation The slots (6) are connected; A specific regular periodic signal is generated by a function generator, and the signal voltage is amplified by a power amplifier to excite the copper coil winding at one end of the annular silicon steel core. The distortion rate of the amplified voltage signal is ≦0.1%. The corresponding regularly changing induced electromotive force in the winding of the spiral silicone tube filled with strong electrolyte solution at the other end of the core is used as the "source power" to drive the directional migration of ions in the immersion liquid system; according to the ionic characteristics of the solution system, select a suitable periodic function waveform To achieve the best impregnation effect; when the periodic function waveform is issued, the conductivity of the strong electrolyte impregnation solution must be in the range of 20-60mS/cm, and the changing magnetic flux can generate 500mV-1.8V alternating current at both ends of the impregnation tank. Variable induction electromotive force, when the thickness of the food material is within 3cm, the impregnation can be completed within 5 minutes, that is, the volume concentration of the solute in the impregnation solution in the internal and external environment of the food material is basically the same. 2. The food dipping and processing method based on the strong electrolyte ion current controlled by the function signal according to claim 1, characterized in that the function signal generator in the drive unit can generate any custom waveform with a frequency of 1 Hz to 100 Hz, one The signal in the cycle has 1 rising edge and 2 falling edges, the slope of the rising edge is greater than the slope of the falling edge, the width range is within 10Vpp, +5V～-5V, the output impedance is 50Ω, and the power amplifier used is compatible with any function waveform Amplification, full power frequency range 1Hz~100Hz, output voltage width 300Vpp, +150V~-150V, output current 0~40mA, input impedance 50Ω. 3. the food dipping processing method based on the strong electrolyte ionic current of function signal control according to claim 1, is characterized in that, the annular silicon steel core in the induction unit is a silicon steel rectangular iron core, and the copper coil winding is a single-layer winding , the copper wire diameter ranges from 0.6 to 0.8 mm, and the number of turns is 120 to 150 turns, which is connected to the power amplifier. 4. The food dipping processing method based on the strong electrolyte ionic current controlled by the function signal according to claim 1, characterized in that, the material of the silicone tube winding full of strong electrolyte dipping solution is good insulation, good flexibility, non-toxic Odorless food-grade platinum silicone tube, the inner diameter ranges from 1 to 5mm, the tube wall thickness is 3mm, the winding is a single-layer winding, and the number of turns ranges from 10 to 20 turns. They are connected and communicated so that the immersion liquid is a loop system that circulates. 5. the food dipping processing method based on the strong electrolyte ionic current of function signal control according to claim 1, it is characterized in that, in the dipping unit, the glass dipping tank is a cylindrical structure inner diameter 80mm, length 300mm, wall thickness 3mm, and the top leaves There are valves that can be vacuumed and sealing covers that can be used for sample injection or sampling. There are conduction ports in the middle of both sides of the dipping tank, which can be connected with silicone tubes, so that the entire dipping liquid system forms a circulation loop, and the dipping liquid system is controlled by a vacuum pump. cycle.

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