Continuous conveying device and continuous conveying method for magnesium chloride molten salt

Abstract

The invention relates to the technical field of electrolytic magnesium production, in particular to a magnesium chloride molten salt continuous conveying device and method, and the magnesium chloride molten salt continuous conveying device comprises a conveying assembly, an electric heat tracing assembly and a composite heat preservation assembly which are sequentially arranged from inside to outside. The first end of the conveying assembly is connected with the magnesium chloride melting device, the second end of the conveying assembly is connected with the magnesium chloride electrolysis device, and the first end is higher than the second end. The composite heat preservation assembly sequentially comprises a fireproof heat insulation layer, an aerogel layer and a high silica cloth layer from inside to outside. The two ends of the transportation assembly are directly connected with the magnesium chloride melting device and the magnesium chloride electrolysis device, physical carrying of high-temperature magnesium chloride molten salt can be avoided, the safety risk faced by operators is remarkably reduced, continuous operation can be achieved, the cooling and loading waiting time in transportation of an existing two-man ladle vehicle is greatly shortened, and the transportation efficiency of the two-man ladle vehicle is improved. And continuous production of magnesium chloride electrolysis is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of electrolytic magnesium production, and in particular relates to a continuous conveying device and a continuous conveying method for magnesium chloride molten salt. Background Art

[0002] As a lightweight, high-strength metal, magnesium is widely used in aerospace, automobile manufacturing, electronic equipment and other fields. Anhydrous magnesium chloride, as a key raw material for the production of metallic magnesium, plays an important role in the magnesium smelting process. Anhydrous magnesium chloride is produced by electrolysis. This process requires the raw material anhydrous magnesium chloride to be in a molten state, and its typical operating temperature is higher than 700°C, which not only places extremely high demands on the heat resistance and corrosion resistance of the equipment, but also makes the transportation of materials a challenge.

[0003] In the prior art, a ladle truck is generally used to transport magnesium chloride molten salt from a magnesium chloride melting device to a magnesium chloride electrolysis device. However, this transportation method has obvious defects:

[0004] First, the use of pallet trucks to transport magnesium chloride molten salt requires waiting for cooling and reloading after each transportation, which will affect the production efficiency and capacity of magnesium chloride electrolysis and make it impossible to achieve continuous production of magnesium chloride electrolysis.

[0005] Second, the physical handling of high-temperature magnesium chloride molten salt increases the risks faced by operators, including but not limited to thermal radiation injuries, burns caused by molten salt splashing, and potential leakage accidents, etc., and there are many safety hazards.

[0006] Therefore, it is necessary to provide a device that can realize continuous and safe transportation of magnesium chloride molten salt, so as to overcome the limitations of discontinuous transportation of ladle trucks and improve the production efficiency and safety performance of magnesium chloride electrolysis. Summary of the invention

[0007] 1. Technical issues to be resolved

[0008] In order to solve the problems in the prior art that the transportation of magnesium chloride molten salt by ladle trucks is low in safety and cannot achieve continuous production, the present invention provides a continuous transportation device and a continuous transportation method for magnesium chloride molten salt.

[0009] (II) Technical solution

[0010] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0011] A continuous conveying device for magnesium chloride molten salt, comprising a conveying component, an electric heating component and a composite insulation component arranged in sequence from the inside to the outside;

[0012] The first end of the conveying assembly is connected to the magnesium chloride melting device, the second end of the conveying assembly is connected to the magnesium chloride electrolysis device, and the height of the first end is higher than the height of the second end;

[0013] The electric heating component is used to heat the conveying component;

[0014] The composite thermal insulation component comprises, from the inside to the outside, a fire-resistant thermal insulation layer, an aerogel layer and a high-silica cloth layer.

[0015] As described above, the continuous conveying device of magnesium chloride molten salt, preferably, the distance between the magnesium chloride melting device and the magnesium chloride electrolysis device is 10-20m; the magnesium chloride melting device is also connected to a gas compression device;

[0016] The conveying assembly includes at least one conveying pipeline; one end of the conveying pipeline is connected to the outlet of the magnesium chloride melting device, and the other end is connected to the inlet of the magnesium chloride electrolysis device;

[0017] When the delivery assembly includes a plurality of delivery pipelines, the plurality of delivery pipelines are connected in sequence;

[0018] The inclination angle of the conveying pipeline is 5-90°.

[0019] In the above-mentioned continuous conveying device for magnesium chloride molten salt, preferably, the conveying pipeline is a high-nickel alloy pipeline.

[0020] In the continuous conveying device for magnesium chloride molten salt as described above, preferably, the conveying pipeline is a π-bend pipeline.

[0021] In the continuous conveying device for magnesium chloride molten salt as described above, preferably, the refractory heat-insulating layer is an aluminum silicate refractory layer.

[0022] The continuous conveying device of magnesium chloride molten salt as described above preferably further comprises a thermal insulation skin layer arranged outside the composite thermal insulation component;

[0023] A salt discharge groove is arranged at the bottom of the thermal insulation skin layer, and a leakage detection component is arranged in the salt discharge groove.

[0024] In the continuous conveying device of magnesium chloride molten salt as described above, preferably, the leakage detection component is a temperature measuring component, and the temperature measuring component includes a plurality of temperature measuring components, and the plurality of temperature measuring components are evenly arranged in the salt discharge tank along the length direction of the conveying pipeline.

[0025] In the continuous conveying device for magnesium chloride molten salt as described above, preferably, the electric heating component includes a plurality of continuous S-shaped bending sections or a plurality of continuous U-shaped bending sections.

[0026] The present invention also provides a method for continuously conveying magnesium chloride molten salt using the above-mentioned continuous conveying device, comprising the following steps:

[0027] S1: Preheat the conveying component to 730-780℃ through the electric heating component;

[0028] S2: The magnesium chloride molten salt in the magnesium chloride melting device enters the interior of the conveying component, and then under the action of gravity, the magnesium chloride molten salt passes through the conveying component and enters the magnesium chloride electrolysis device.

[0029] In the continuous conveying method of magnesium chloride molten salt as described above, preferably, in step S2, when the flow rate of the magnesium chloride molten salt in the conveying component is less than a preset value, the compressed gas in the gas compression device enters the magnesium chloride melting device to increase the flow rate of the magnesium chloride molten salt, thereby making the flow rate of the magnesium chloride molten salt in the conveying component greater than or equal to the preset value.

[0030] (III) Beneficial effects

[0031] The beneficial effects of the present invention are:

[0032] First, in the continuous conveying device of magnesium chloride molten salt of the present invention, both ends of the transport component are directly connected to the magnesium chloride melting device and the magnesium chloride electrolysis device, which can operate continuously, greatly reducing the cooling and loading waiting time in the existing ladle truck transportation, improving the production efficiency and capacity of magnesium chloride electrolysis, and realizing the continuous production of magnesium chloride electrolysis.

[0033] Second, the magnesium chloride molten salt continuous conveying device of the present invention can also avoid the physical transportation of high-temperature magnesium chloride molten salt, significantly reduce the safety risks faced by operators, and improve the safety performance of the working environment.

[0034] Third, the composite thermal insulation assembly of the present invention includes a refractory insulation layer, an aerogel layer and a high-silica cloth layer from the inside to the outside, which can effectively reduce the heat loss during the transportation of the magnesium chloride molten salt, maintain the temperature of the magnesium chloride molten salt, reduce energy consumption, and also reduce the impact of thermal radiation on the external environment.

[0035] Fourth, in the continuous conveying device of magnesium chloride molten salt of the present invention, the two ends of the transport component have different heights, and gravity can be used to assist the flow of magnesium chloride molten salt, thereby reducing the power demand for transportation, optimizing the structural design, and enhancing the overall durability and reliability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the overall structure of the continuous conveying device of magnesium chloride molten salt in the present invention;

[0037] Figure 2 It is a cross-sectional view of a continuous conveying device for magnesium chloride molten salt in the present invention;

[0038] Figure 3 It is a cross-sectional view of the composite thermal insulation component of the present invention (the electric heating component is not shown in the figure);

[0039] Figure 4 It is a structural schematic diagram of the delivery pipeline in the present invention;

[0040] Figure 5 It is a schematic diagram of the structure of the electric heating component in the present invention.

[0041] [Description of Reference Numerals]

[0042] 1: Conveying component; 11: Conveying pipeline; 2: Electric heating component; 3: Composite insulation component; 31: Refractory insulation layer; 32: Aerogel layer; 33: High silica cloth layer; 4: Insulating skin layer; 5: Salt discharge tank; 6: Leakage detection component; 7: Magnesium chloride melting device; 8: Magnesium chloride electrolysis device; 9: Gas compression device. DETAILED DESCRIPTION

[0043] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0044] like Figure 1-Figure 5 As shown, the present invention provides a continuous conveying device for magnesium chloride molten salt, comprising a conveying component 1, an electric heating component 2 and a composite insulation component 3 arranged in sequence from the inside to the outside. The first end of the conveying component 1 is connected to the magnesium chloride melting device 7, and the second end of the conveying component 1 is connected to the magnesium chloride electrolysis device 8, and the height of the first end is higher than the height of the second end. The electric heating component 2 is used to heat the conveying component 1. The composite insulation component 3 includes a refractory insulation layer 31, an aerogel layer 32 and a high silica cloth layer 33 in sequence from the inside to the outside.

[0045] In the continuous conveying device of magnesium chloride molten salt of the present invention, the two ends of the transport component 1 are directly connected to the magnesium chloride melting device and the magnesium chloride electrolysis device, which can realize continuous operation, greatly reduce the cooling and loading waiting time in the existing bag-lifting vehicle transportation, improve the production efficiency and production capacity of magnesium chloride electrolysis, and realize the continuous production of magnesium chloride electrolysis. The continuous conveying device of magnesium chloride molten salt of the present invention can also avoid the physical handling of high-temperature magnesium chloride molten salt, significantly reduce the safety risks faced by operators, and improve the safety performance of the working environment.

[0046] In the continuous conveying device of magnesium chloride molten salt of the present invention, there is a height difference between the two ends of the transport component 1, so that gravity can be used to assist the flow of magnesium chloride molten salt, reduce the power requirement for conveying magnesium chloride molten salt, and enhance the overall durability and reliability of the continuous conveying device.

[0047] The composite thermal insulation component of the present invention includes a refractory insulation layer, an aerogel layer and a high-silica cloth layer from the inside to the outside. This structural design from the inside to the outside can effectively reduce the heat energy loss during the transportation of the magnesium chloride molten salt, maintain the temperature of the magnesium chloride molten salt, reduce energy consumption, and also reduce the impact of thermal radiation on the external environment.

[0048] Preferably, the fire-resistant heat-insulating layer 31 in the present invention is an aluminum silicate fire-resistant layer, specifically made of high-temperature resistant aluminum silicate material, the aerogel layer 32 is made of aerogel material, and the high-silica cloth layer 33 is made of high-silica cloth material.

[0049] The thickness of the aluminum silicate refractory layer in the present invention can be 250-500 mm, the thickness of the aerogel layer 32 can be 80-170 mm, and the thickness of the high-silica cloth layer 33 can be 0.6-1.3 mm.

[0050] As the layer closest to the high-temperature transmission pipeline, the aluminum silicate refractory layer has excellent high-temperature resistance and a certain degree of thermal insulation. Aerogel has an extremely low thermal conductivity. It is set on the outer layer of the aluminum silicate refractory layer to minimize heat conduction, provide efficient thermal insulation, and prevent heat from diffusing outward. High-silica cloth mainly plays a role in protection and auxiliary insulation, which can be affected by the external environment. At the same time, due to its good thermal insulation performance, it can further reduce heat loss and improve the overall thermal insulation effect.

[0051] In addition, after actual verification, for the present invention, if the arrangement order of the refractory insulation layer 31, the aerogel layer 32 and the high silica cloth layer 33 is changed, for example, it is arranged as an aerogel layer + a silicate cloth layer + an aluminum silicate layer from the inside to the outside, or it is arranged as an aluminum silicate layer + a high silica cloth layer + an aerogel layer from the inside to the outside, the insulation effect of the composite insulation component 3 on the conveying pipeline 11 will be affected, making it impossible to realize pipeline transportation of magnesium chloride molten salt, and the continuous conveying device of the magnesium chloride molten salt of the present invention cannot be used.

[0052] Preferably, the first end of the conveying assembly 1 is connected to the outlet of the magnesium chloride melting device 7 , and the second end of the conveying assembly 1 is connected to the inlet of the magnesium chloride electrolysis device 8 .

[0053] Further preferably, the conveying assembly 1 includes at least one conveying pipeline 11, one end of the conveying pipeline 11 is connected to the outlet of the magnesium chloride melting device 7, and the other end is connected to the inlet of the magnesium chloride electrolysis device 8. When the conveying assembly 1 of the present invention adopts two or more conveying pipelines, the pipeline overpressure caused by the blockage of the magnesium chloride molten salt can be avoided. Specifically, when the conveying assembly 1 includes two or more conveying pipelines 11, the multiple conveying pipelines 11 can be connected in sequence through short pipes to achieve the effect of connecting each conveying pipeline 11 in parallel, so that when one of the conveying pipelines is blocked, the magnesium chloride molten salt can still enter the adjacent conveying pipeline through the short pipe for transportation.

[0054] In the present invention, the inclination angle of the conveying pipeline 11 can be 5-90 degrees, so as to utilize gravity to assist the flow of the magnesium chloride molten salt.

[0055] The continuous conveying device of the present invention can realize a conveying distance of 10-20 m for magnesium chloride molten salt. Therefore, the distance between the magnesium chloride melting device 7 and the magnesium chloride electrolysis device 8 can be between 10-20 m.

[0056] In addition, when the conveying pipeline 11 is inclined at a certain angle but the flow rate of the magnesium chloride molten salt is still slow, a gas compression device 9 can also be provided at the other end of the magnesium chloride melting device 7. The compressed gas in the gas compression device 9 can increase the flow rate of the magnesium chloride molten salt in the magnesium chloride melting device 7, so as to further increase the flow rate of the magnesium chloride molten salt in the conveying assembly 1.

[0057] Preferably, the delivery pipeline 11 is a high-nickel alloy pipeline, and the above-mentioned short pipe is also a high-nickel alloy pipeline. High-nickel alloy is an alloy composed of nickel as a matrix and other elements added, wherein the main alloy elements include but are not limited to chromium, tungsten, molybdenum, cobalt, aluminum, titanium, boron, zirconium, etc. High-nickel alloy has high strength and high temperature resistance, and has excellent corrosion resistance. It can still form a stable passivation layer at high temperature to protect the internal metal from further erosion, so it can withstand the corrosion of high-temperature magnesium chloride molten salt.

[0058] When the magnesium chloride molten salt is transported in the transport pipeline 11, when the temperature of the transport pipeline 11 increases significantly, the transport pipeline itself absorbs heat, the thermal motion of the molecules increases, and the average distance between the molecules increases, causing the volume of the transport pipeline 11 to expand, which is manifested as an increase in the length of the pipeline and thermal expansion. The transport pipeline 11 will generate thermal stress due to thermal expansion, and long-term thermal stress may cause material fatigue or even structural damage to the transport pipeline.

[0059] In order to solve the disadvantages caused by thermal expansion, preferably, in the continuous conveying device of magnesium chloride molten salt of the present invention, the conveying pipeline 11 is a π-bend pipeline.

[0060] Pi-bend pipes provide extra length and flexibility, allowing the pipeline to stretch along a curved path when thermal expansion occurs without placing excessive stress on the straight section. Specifically, when the pipeline expands due to rising temperature, the radius of the π-bend portion remains unchanged, but its arc length increases, which is equivalent to increasing the total length of the pipeline, thereby relieving the stress on the straight section. Similarly, when the temperature of the pipeline decreases, the pipeline contracts and the arc length of the π-bend portion decreases, but it does not cause a pulling effect on the straight section of the pipeline. In addition, π-bend pipes are simple in structure and relatively low in cost, while reducing the need for expensive mechanical expansion joints and reducing the complexity of maintenance.

[0061] Further preferably, the continuous conveying device of magnesium chloride molten salt of the present invention further comprises an insulation skin layer 4 arranged outside the composite insulation component 3, and the thickness of the insulation skin layer 4 is 0.3-0.7 mm. The insulation skin used in the insulation skin layer 4 can be stainless steel material or aluminum alloy material.

[0062] Preferably, in order to detect in real time whether the magnesium chloride molten salt in the conveying pipeline 11 is leaking, the present invention further provides a salt discharge tank 5 at the bottom of the thermal insulation skin layer 4 , and a leakage detection component 6 is provided in the salt discharge tank 5 .

[0063] The leakage detection component 6 is preferably a temperature measuring component, and the temperature measuring components include multiple temperature measuring components, which are evenly arranged in the salt discharge tank 5 along the length direction of the conveying pipeline 11. The above-mentioned temperature measuring component can be a thermocouple, etc. When the conveying pipeline 11 and the composite insulation component 3 are in a normal state, the temperature in the salt discharge tank 5 is generally 40-50°C. However, if the magnesium chloride molten salt in the conveying pipeline 11 leaks, the temperature in the salt discharge tank 5 will rise sharply. Therefore, the temperature data obtained by the temperature measuring component can be used to determine in real time whether the magnesium chloride molten salt in the conveying pipeline 11 has leaked, and the leakage point can be quickly determined according to the location of the temperature measuring component.

[0064] Preferably, in the continuous conveying device of magnesium chloride molten salt of the present invention, the electric heating component 2 is wound around the outside of the conveying pipeline 11 in a serpentine arrangement, and the electric heating component 2 specifically includes a plurality of continuous S-shaped bending sections or a plurality of continuous U-shaped bending sections.

[0065] The electric heating assembly 2 of the present invention is arranged in a serpentine manner on the surface of the conveying pipe 11, rather than being directly wound, mainly because the conveying pipe 11 will experience thermal expansion during the magnesium chloride molten salt process. The conveying pipe 11 will undergo dimensional changes during thermal expansion. If the electric heating assembly 2 is directly wound on the conveying pipe 11, then as the conveying pipe 11 expands, the electric heating assembly 2 will also be forced to follow the expansion, which may cause the wires or conductive materials inside the electric heating assembly 2 to be subjected to tensile stress and then damaged.

[0066] In addition, the present invention can also be provided with a control component to regulate the opening and closing of the electric heating component. For example, when the temperature of the conveying component and the magnesium chloride is lower than 720°C, the control component turns on the electric heating component to heat the conveying component and the magnesium chloride. When the temperature of the conveying component and the magnesium chloride exceeds the set value, the control component turns off the electric heating component to avoid overheating.

[0067] On the other hand, the present invention also provides a method for continuously conveying magnesium chloride molten salt using the above-mentioned continuous conveying device, comprising the following steps:

[0068] S1: preheating the conveying component 1 to 730-780° C. by the electric heating component 2, matching the melting temperature of magnesium chloride.

[0069] S2: The magnesium chloride molten salt in the magnesium chloride melting device 7 enters the interior of the conveying component 1, and then under the action of gravity, the magnesium chloride molten salt passes through the conveying component 1 and enters the magnesium chloride electrolysis device 8.

[0070] Preferably, in step S2, when the flow rate of the magnesium chloride molten salt in the conveying component 1 is less than a preset value, the compressed gas in the gas compression device 9 enters the magnesium chloride melting device 7 to increase the flow rate of the magnesium chloride molten salt, thereby making the flow rate of the magnesium chloride molten salt in the conveying component 1 greater than or equal to the preset value.

[0071] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0072] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0074] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A continuous conveying device for magnesium chloride molten salt, characterized in that, It comprises a conveying component (1), an electric heating component (2) and a composite thermal insulation component (3) which are arranged in sequence from the inside to the outside; The first end of the conveying component (1) is connected to the magnesium chloride melting device (7), the second end of the conveying component (1) is connected to the magnesium chloride electrolysis device (8), and the height of the first end is higher than the height of the second end; The electric heating component (2) is used to heat the conveying component (1); The composite thermal insulation component (3) comprises, from the inside to the outside, a fire-resistant thermal insulation layer (31), an aerogel layer (32) and a high-silica cloth layer (33).

2. The continuous conveying device of magnesium chloride molten salt according to claim 1, characterized in that: The distance between the magnesium chloride melting device (7) and the magnesium chloride electrolysis device (8) is 10-20 m; the magnesium chloride melting device (7) is also connected to a gas compression device (9); The conveying assembly (1) comprises at least one conveying pipeline (11); one end of the conveying pipeline (11) is connected to the outlet of the magnesium chloride melting device (7), and the other end is connected to the inlet of the magnesium chloride electrolysis device (8); When the conveying assembly (1) comprises a plurality of conveying pipes (11), the plurality of conveying pipes (11) are connected in sequence; The inclination angle of the conveying pipeline (11) is 5-90°.

3. The continuous conveying device of magnesium chloride molten salt according to claim 2, characterized in that: The delivery pipeline (11) is a high-nickel alloy pipeline.

4. The continuous conveying device for magnesium chloride molten salt according to claim 2, characterized in that: The delivery pipeline (11) is a π-bend pipeline.

5. The continuous conveying device of magnesium chloride molten salt according to claim 1, characterized in that: The fire-resistant heat-insulating layer (31) is an aluminum silicate fire-resistant layer.

6. The continuous conveying device of magnesium chloride molten salt according to claim 2, characterized in that: It also includes a thermal insulation skin layer (4) arranged outside the composite thermal insulation component (3); A salt discharge groove (5) is arranged at the bottom of the thermal insulation skin layer (4), and a leakage detection component (6) is arranged in the salt discharge groove (5).

7. The continuous conveying device of magnesium chloride molten salt according to claim 6, characterized in that: The leakage detection component (6) is a temperature measuring component, and the temperature measuring component includes a plurality of temperature measuring components, and the plurality of temperature measuring components are evenly arranged in the salt discharge tank (5) along the length direction of the conveying pipeline (11).

8. The continuous conveying device of magnesium chloride molten salt according to claim 1, characterized in that: The electric heating component (2) comprises a plurality of continuous S-shaped bending sections or a plurality of continuous U-shaped bending sections.

9. A method for continuously conveying magnesium chloride molten salt using the continuous conveying device according to any one of claims 1 to 8, characterized in that: The steps include: S1: preheating the conveying component (1) to 730-780° C. by means of an electric heating component (2); S2: The magnesium chloride molten salt in the magnesium chloride melting device (7) enters the interior of the conveying component (1), and then under the action of gravity, the magnesium chloride molten salt passes through the conveying component (1) and enters the magnesium chloride electrolysis device (8).

10. The method for continuously conveying magnesium chloride molten salt according to claim 9, characterized in that: In step S2, when the flow rate of the magnesium chloride molten salt in the conveying component (1) is less than a preset value, the compressed gas in the gas compression device (9) enters the magnesium chloride melting device (7) to increase the flow rate of the magnesium chloride molten salt, thereby making the flow rate of the magnesium chloride molten salt in the conveying component (1) greater than or equal to the preset value.

Images