RU2121529C1 - Method of feeding aluminum electrolyzer with alumina and correcting additions and device for its embodiment - Google Patents

Abstract

FIELD: methods and devices for feed of aluminum electrolyzers. SUBSTANCE: in feed of aluminum electrolyzer with alumina, hole in crust is maintained nonclosing by cyclic reciprocating of punches with their shortest time staying in extreme lower position. Provision is made for flowing of material into electrolyte melt through slotted discharge hole in side wall of vessel under material gravity. Cutting off the material flow in regulation of dose value is carried out by self-closing of discharge hole after discontinued supply of aerating pulses. The device for embodiment of the claimed method includes bin for loose reagents, metering device with case, chute and means for regulation of conditions of reagent supply, punch with drive connected to unit of supply of pneumatic pulses and control. Means for regulation of conditions of supply of loose reagents are made in the form of aerating box with gas permeable member. Aerating box is connected to unit of supply of pneumatic pulses and control. Gas permeable member serves as bottom of metering device case. Front wall of case is installed in a spaced relation to bottom protruding beyond the case and forms chute together with guide sides fastened to case. Provision is made for means of variation of an angle of inclination of metering device body in vertical plane. EFFECT: rational feed of raw materials, reproducible doses, reduced energy consumption and losses of reagents, easy integration with existing systems of automated control of production processes. 7 cl, 3 dwg

Description

 The invention relates to ferrous metallurgy, and in particular to the production of aluminum by electrolysis from cryolite-alumina melts and can be used in the automated supply of alumina and additives to the electrolyzer.

 There are various ways of automated feeding electrolyzers with raw materials and additives used in the aluminum industry. The process flow diagram is unchanged for various implementations and consists in forming a hole in the electrolyte crust and introducing a predetermined amount of alumina and additives into the melt. Punches and batchers are used for this purpose, controlled independently from the automation system by the electrolysis process, while pneumatic automation tools are widely used. However, specific modes of supply of raw materials and equipment used have features that generally determine the performance, energy consumption and stability of the operation of the automated power system.

 So, there is a known method and device for automatically feeding aluminum electrolysis cells with alumina, in which volume-vacuum dispensers are used, interlocked with a pneumatic cylinder, on the piston of which a punching mechanism is fixed (SU 0461973, VNIIIPI aluminum., C 25 C 3/20, 3/14 , 02.28.75). Alumina feed rate is controlled by changing the frequency of supply of pneumatic pulses, based on the current state of the electrolysis process. However, this method requires the implementation of a large flow of compressed air and is not able to provide sufficient efficiency in the supply of materials: the punch cyclically “pushes” pre-fed alumina to the crust.

 Another way to power the electrolyzer (SU 1611992 A1, Petukhov et al., C 25 C 3/14, 12/07/90) involves loading alumina with a layer of a given thickness onto the surface of the electrolyte crust, followed by forcing the crust into the electrolyte. The device for this purpose is a plate of heat-resistant material with through slots, rigidly connected to the hopper. However, this technique does not allow to quickly control the concentration of alumina in the melt with the help of the process control system and does not guarantee from alumina dips into cracks that appear on the crust when it is forced by the plate. When the temperature of the electrolyte increases, for example, when a prolonged anode effect or a breakdown in technology occurs, the crust will melt, and all the alumina from the hopper falls on the bottom of the cell, which is highly undesirable. The method cannot be applied in the starting period, in which the crust is absent. Moving a bunker with alumina and a stove requires significant energy consumption.

 Another invention (US 3901787, NIIZEKI et al., 204/245, 26.08.75) describes a method and device for feeding raw materials to an electrolytic bath, in which the dispenser has two independent aerial channels, one of which is used to fill the measuring chambers - pipes, and the other for dropping the accumulated doses through the guide tubes of the punches on the electrolyte crust. The invention (SU 1611993 A1, Tajik Aluminum Plant and others, C 25 C 3/14, 12/07/90) describes a power device with separate placement of a punch and a dispenser. Alumina is fed into the dispenser and unloaded by means of a pneumatic chute and aeration system. In these methods, the value of the delivered dose is unchanged (1 - 2.5 kg), it is determined by the volume of the dispenser and the bulk weight of alumina.

 The closest analogue to the claimed group of inventions is a method of dosed supply of alumina and a device for its implementation (CH 651074 A5, SCHWEIZERISHE ALUMINIUM AG ..., C 25 C 3/14, 30.08.85). According to the invention, the feed is supplied to the feed point by pulses with adjustable duration and frequency, changing the dose if necessary. The minimum value of the delivered dose is limited by the lower inertia limit of the control electro-pneumatic valve. However, the known technical solution is characterized by disadvantages. The actuation of the pneumatic cylinder of the punch synchronized with the opening of the valve when feeding low doses will lead to a significant consumption of compressed air, and its high pressure of 0.4 - 0.6 MPa leads to significant dusting and entrainment of alumina into the exhaust gas system. Dispensers are sensitive to changes in alumina properties and require high precision manufacturing.

 The objective of the group of inventions is to create a method and device for the automated power supply of electrolyzers with increased efficiency and quality of the process by ensuring a rational supply of raw materials, reproducibility of doses, reducing energy costs and losses of dosed reagents, integration with existing automated process control systems.

 The technical result of the method is ensured by the fact that the process of feeding the aluminum electrolyzer with alumina and corrective additives includes a dosed supply of granular material from the tank into the electrolyte melt through holes in the crust formed by punches performing reciprocating movement and adjusting the dose of the material by means of pneumatic pulses with controlled parameters . The holes in the crust are maintained non-fouling by means of the cyclic operation of the punches while minimizing their time in the lowest position, while creating conditions for the free flow of material through the slit-like outlet in the side wall of the tank under the action of aerated pneumatic pulses introduced into the layer moving under the action of gravity of the material and the material is cut off when adjusting the dose by self-locking the said outlet after stopping under chi pneumatic aerating pulses.

 The method can be characterized by the fact that the time spent by the punch in its lowest position is 1-2 seconds, and also by the fact that the dose of bulk reagents is set in the range from 0.05 to 0.35 kg per hole, and ceteris paribus feed the cell increased doses at food points where the electrolyte circulation rate is higher.

 The method can be characterized in that the pressure difference created by pneumatic pulses under the gas-permeable bottom and above it is 0.05-2 kPa.

 The technical result of the device is ensured by the fact that it includes a hopper for bulk reagents, a dispenser with a casing, estrus and means for regulating the reagent supply mode, a puncturer with a drive connected to the pneumatic impulse supply and control unit. Means for regulating the flow of bulk reagents are made in the form of an aeration box with a gas-permeable element connected to a pneumatic pulse supply unit with a regulator. The gas-permeable element is the bottom of the dispenser casing, the front wall of the casing is installed with a gap relative to the bottom protruding outside the casing, and together with the guide sides fastened to the casing, forms a estrus.

 The device can be characterized in that the aeration box with a gas-permeable element is made of heat-conducting, thermo-, wear-resistant material, and also that the dispenser is equipped with means for changing the angle of inclination of the dispenser body in a vertical plane.

The invention is illustrated in the drawings, where:
in FIG. 1 shows a block diagram of a device,
in FIG. 2 shows the design of the dispenser, side view,
in FIG. 3 is the same as in FIG. 2, a sectional view along AA.

 The patented group of inventions is based on the conditions established by the inventors and based on experimental data for the rational construction of a technological scheme for supplying electrolysis cells with alumina and corrective additives. In doing so, the following points are taken into account.

Theoretically, the maximum concentrated dose of alumina (according to Gibbs energy), capable of dissolving at 960 ^o C in an electrolyte with a layer of 19-21 cm, does not exceed (700 ± 30) g. In practice, this value is 2-5 times less and depends on the type of alumina, its solubility, specific surface area, α-phase content, cryolite ratio, temperature and melt circulation rate of the concentration of previously dissolved alumina in it. Doses of alumina 1 - 2.5 kg given into estrus cause a sharp hypothermia of the local volume of the electrolyte, its supersaturation and only partially dissolve. Therefore, under the punches on the bottom of the cell there is always a precipitate, the accumulation of which worsens the operation of the cell, up to the breakdown of technology. At the same time, the modern control system exacerbates the state of the electrolyzer: by analyzing its state, it makes an erroneous conclusion that the concentration of alumina in the electrolyte is insufficient and reduces the intervals between flows.

 To ensure acceptable dissolution of doses of alumina, a special “sand” alumina is used, which, dissolving 20 to 40% faster, reduces the amount of sediment on the bottom, stabilizes the process, increases the current efficiency by 1-3%. However, the cost of “sand” alumina is about one third higher and poorly transported by high-pressure pneumatic conveying (M.P. Petukhov et al. “Necessity and peculiarity of using sand alumina at KrAZ OJSC” .// Collection of reports of a scientific and technical seminar on the problem of “Sand alumina” : production and application ", JSC VAMI, CJSC" Aluminum ", September 11-12, 1997, St. Petersburg, 1997).

Each dose of alumina (regardless of its type) weighing 1-2.5 kg is accompanied by the movement of the punch due to the fact that alumina causes freezing of the hole. The punch performs a cycle: downward movement for 2 - 3 seconds, has a delay below - 8 - 16 seconds, upward movement 2 - 3 seconds. In this case, the working body of the punch is heated to 700-900 ^o C, oxidized, and sometimes dissolves in contact with the electrolyte. This reduces the grade of aluminum and the overhaul life of punches.

To increase the solubility of alumina can be a significant (3-20 times) reduction in the dose per hole. However, with the usual feeding methods and the use of known devices, this will cause a corresponding decrease in the life of the dispensers, punches and their drives, because they act in an abrasive medium, in an atmosphere of aggressive gases, at temperatures of 100-400 ^o C and in conditions of strong magnetic fields of 50 - 150 G. Existing systems are the main consumers of compressed air: a housing of 80 electrolyzers for a current of 255 kA, with six punches and six batchers each, with a bucket batcher volume (1.5 ± 0.4) kg, consumes (107 ± 10) nm ³ compressed air per minute. So, for example, with a decrease in the volume of the bucket dispenser to 0.25 kg and an increase in the feed frequency by 6 times, the flow rate of compressed air and lubricants for pneumatic cylinders increases proportionally.

Thus, for an efficient process when feeding electrolysis cells with alumina and corrective additives, the following conditions must be satisfied:
- alumina must be introduced under a cryolite-alumina crust into a layer of molten electrolyte with a height of 10-30 cm with a cryolite ratio of 1.8-3.0 and its complete dissolution, regardless of type (“powdery”, “intermediate”, under-calcined, coarse-grained) - “sandy”), α-phase content, solubility, fractional composition and other physicochemical properties;
- the concentration of dissolved alumina should be maintained in a predetermined range, excluding local supercooling and supersaturation of the melt in the places where the alumina is introduced, the formation of precipitation on the bottom of the cell, and the occurrence of random anode effects when the concentration is reduced;
- the process must be compatible with the process control systems (ACS), make maximum use of their capabilities with the exception of unnecessary technological operations for the processing of electrolyzers;
- the process should ensure minimal loss of reagents and their release into the atmosphere, as well as the cost of introducing reagents into the electrolyte.

 Accordingly, the means for the automated supply of aluminum electrolytic cells should ensure accurate reproducibility of doses over a wide range of changes in their magnitude. With the anode effect, the device should saturate the electrolyte with alumina in no more than 2-3 minutes, and for this the filling time of the dispenser and its discharge should be minimal. During operation, dusting and loss of dosing material should be minimized. The device should consume a minimum of electricity, be economical in the consumption of compressed air, lubricants. The characteristics of the device during operation should be unchanged or changed to a minimum extent when using various alumina.

In addition, the following requirements must be met when implementing the device:
- the design must reliably lock reagents in the absence of supply, to exclude spontaneous unloading, including when loading into the hopper under excessive pressure;
- when dispensing abrasive material at elevated temperatures of 150-400 ^o C, high dust, exposure to aggressive gases, the device must have an overhaul period of not less than the life of the cell;
- the control elements of the device must be compatible with modern automation;
- for electrolyzers with self-baking anodes, the bell-shaped space should be sealed, and for electrolyzers of all types - do not allow the emission of exhaust gases into the atmosphere.

 The proposed device is devoid of the above disadvantages of the prototype and more fully meets modern requirements.

 The device (Fig. 1) consists of a hopper 10 for alumina 12, in the lower part of which a dispenser 14 is placed, the open part of which forms a estrus 16. On the estrus side 16, a punch 18 with a drive 20. A pneumatic pulse supply unit 22 is connected to a compressed air source (in Fig. nepokan) by the highway 24. The output lines 26, 28 are connected respectively to the dispenser 14 and to the drive 20 (instead of a pneumatic drive, it is possible to use an electric drive, which, however, does not apply to the essence of the invention). Block 22 is connected to a control unit 30, which generates control signals for pneumatic valves 32, 34. In the lower part of FIG. 1, a hole 36 formed in the electrolyte crust 38 covering the cell bath 40 is conventionally shown.

 The dispenser 14 (figure 2) is attached to the lower part of the hopper 10, which contains elements 42 (for example, plates, shutters) to ensure the constancy of the height of the column, which determines the speed of the reagent. The casing 44 is rigidly bonded to the aeration box 46, which is a solid material duct 48 having a gas permeable member 50. The gas permeable member 50 functions as the bottom 52 of the dispenser housing 44. Element 50 may form the entire bottom, or part of the bottom. The front wall 54 of the casing is installed with a gap relative to the bottom 52, which forms the outlet in the side wall - the metering slit 56. The bottom protrudes (pos. 58) beyond the casing 44 and together with the guide sides 60 fastened to the casing, forms a estrus 16. Highway 26 it is connected to the aeration box 46 through the nozzle 62. To adjust the tilt of the dispenser vertically there is a hinge suspension 64 between the hopper 10 and the casing 44, as well as a rod 66, through the hinge suspension 68 connected to the sides 60. The direction of movement of the rod 66 is schematically rendered by arrow 70. The axis of the punch 18 is shown at 72.

The aeration box 46 with the gas permeable member 50 is made of a heat-conducting, thermally wear-resistant material, for example, porous ceramics, porous stainless steels, brass. The bottom may have a flat, convex or concave shape. The specific hydraulic resistance of the material of the bottom should not exceed 0.1 MPa, since at high pressures it is necessary to take measures to additionally strengthen the bottom from the outside. The material of the bottom 52 must withstand temperatures up to 600 ^o C without deformation and destruction, the load from the column of alumina or additives, and the pores of the material should not allow particles of the dosed substance into the aeration box.

 The method of nutrition is as follows.

 The punch 18 punches, and then supports a non-growing hole 36 in the electrolyte crust 38 with periodic movements with an interval of 120-1400 sec. In the absence of pneumatic pulses in line 26, alumina (or loose corrective additives), the filling hopper and the dispenser cavity, is stationary due to the pneumatic layer shutter formed at the outlet of the metering slot 56, the dimensions of which depend on the angle of repose of this alumina, the height of the slit, and the angle of inclination dispenser (bottom) to the horizon.

 To move the material into the aeration box 46 serves compressed air with a pressure greater than the hydraulic resistance of the bottom. In this case, the angle of repose will change, the pneumatic layer shutter is destroyed, the dosed material expires along the estrus towards the hole in the electrolyte. The air pressure is regulated so that its flow rate is minimal, but sufficient for accurate dosing with a maximum dose deviation of ± 5-6%. Pressure exceeding the hydraulic resistance of the bottom by less than 0.05 kPa is small for dosing individual alumina with an α-phase content of more than 32%. Pressure exceeding the hydraulic resistance of the bottom by more than 2 kPa creates a "fluidized bed" of material, its segregation by size, increased dusting when supplied and increases the flow rate of compressed air. The parameters of air (pneumatic pulses) are selected so that the dosed alumina expires evenly and smoothly, with a minimum productivity of 6 - 10 kg per dispenser per minute.

Implementation example. The batchers installed on the alumina bunker an operating electrolyzer with automated control, on which a conventional bucket-type metering device, with an appropriate control algorithm, had previously been used. The control algorithm of the electrolyzer was changed in order to ensure the implementation modes of the patented method. Dosers are designed for an electrolyzer of 190 kiloamperes, the need for which is alumina with an anode effect of 70-72 kg, and the time to eliminate the anode effect is limited to 120 seconds. Each dispenser had a horizontally mounted bottom made of porous stainless steel with a hydraulic resistance of 0.5 kPa (50 mm water column) with dimensions (182 • 44) mm. The vertical front wall forms a metering slit with a bottom 18 mm high and 53 mm wide. All dispensers were connected with a single air hose to a P-EPRZ type air distributor with a nominal diameter of 1.6 mm, a rated power of an electromagnet of 9 W, and a maximum response frequency of 1600 min ^-1 . The pressure in the compressed air line was 0.55-0.6 MPa. Alumina dosing result: at an air flow rate of about 0.3 normal liters per second, for 2.08 seconds each dispenser delivers stably (243 ± 11) g, and for 121.21 sec - (14020 ± 106) g alumina, (total 70.2 kg). Alumina outflow is smooth, uniform, without dusting, with an almost instantaneous start and end at the moment of switching on and off by the control pneumatic signals block 22. A similar linear dependence of the dose value with the duration of the supplied pneumatic pulses was obtained for the corrective additive: doses from 96 g to (345 ± 21) g are set respectively by the dosing time from 0.549 sec to 1.648 sec. The duration of the start was controlled by an electronic stopwatch with an accuracy of 0.001 sec.

 Electrolyzers with 190 kiloamperes have a high electrolyte circulation rate under the third punch. The draft angle changed the angle of inclination of the third dispenser, increasing the dose to 370 g, until an alumina precipitate appeared. The angle of inclination was reduced and a dose of 300 g of alumina was left appropriate. In the same electrolytic cells, the melt circulation pattern is the same, therefore, on the remaining electrolyzers, the same dose was set under the third batcher. Some electrolyzers, for example, at the end of the casing, have noticeably different melt circulation, therefore, dispensers can be individually configured on them.

For practical alumina of the “intermediate” type with an α-phase content of 22–40%, an angle of repose of 30–40 ^o , a bulk density of 0.85–1.15 g / cm ³ , and a content of dust fractions (-45 μm) 10 -30%, the dose of 230-250 g with a pulse duration of 2.08 seconds was sufficient. Tests of sand-type alumina did not require changes and did not show any features. For alumina that are more difficult to dissolve, the dose can be easily reduced. It is possible to make dispensers with a variable height of the dispensing slit and adjusting to achieve the required dosages of the material. The device requires the supply of dust-free inclusions and lubricating oils free of air. Only a pneumatic distributor, for example, type P-EPRZ, with a movable valve, can limit its service life. For the mentioned pneumatic distributor, the mean time between failures according to the passport is 8 • 10 ⁶ cycles. At a maximum frequency of 1 cycle in 30 seconds (1051200 cycles per year), the service life is about 7.6 years, which corresponds to the life of the best electrolytic cells. Approximately the same service life is also observed for punching devices, which, according to the invention, operate 3-15 times less than in known solutions. The proposed method involves minimizing the delay (up to 1-2 seconds) of the punch in the lowest position. The punch, even after touching the melt, does not have time to heat up, while their service life is increased.

 The minimum dose of 0.05 kg per hole is determined from the conditions of alumina getting on the surface of the melt. At a lower dosage, the convective flows of hot gas leaving the hole in the crust pick up alumina, and a significant part of it flies into the gas duct of the gas purification. As a result, the dust load of the gas treatment increases, which leads to an increase in the power of smoke exhausters and unnecessary energy consumption. The maximum dose for metallurgical alumina grades "GO" and "G-OO" - 0.35 kg. It does not produce precipitation only at those supply points where there is always a high electrolyte circulation rate. At points where the speed is minimal, this dosage causes the appearance of a precipitate 2-4 cm thick on the bottom of the cell. The optimal dose is chosen within these limits, based on the temperature of the electrolysis, the rate of circulation of the electrolyte, its cryolite ratio, with the obligatory achievement of the complete dissolution of doses of alumina under the punch.

 The dosage frequency is set based on the conditions of maintaining the optimal concentration of alumina in the electrolyte and maximizing either the current efficiency (at minimum concentrations) or the energy efficiency (at concentrations corresponding to the minimum voltage drop in the electrolyte at a given anode-cathode interpolar distance).

At small (less than 0.35 kg) doses of alumina, they dissolve quickly enough without supersaturated and without cooling the melt, so there is no need to accompany each dose with the movement of the punch, it is enough to get into the hole. Punches do reciprocating movements at intervals of 120-1400 seconds to keep the opening in the crust non-fouling. This frequency is 3 to 10 times less than with ordinary food, but it is sufficient and provides a corresponding reduction in energy costs for the work of punch. It is impractical to carry out movement with punches with a longer than 1400 sec interval, since a change in the external temperature can lead to the appearance of a crust in the hole, the delay of alumina on it and the appearance of random anode effects. In practice, a hole with a diameter of 96 mm in the spacing of the anodes with a cryolite ratio of 2.65 freezes at a temperature in the electrolysis body of minus 27 ^o C for 1080-1140 seconds, if large doses of alumina are not supplied to the hole. In the proposed method, the saturation of the electrolyte with alumina with the anode effect can be achieved by switching on the dispensers for 90-180 seconds while reducing the interval between the work cycles of the punch. For 90-180 seconds, the dispensers supply 10-22 kg of alumina per hole, and the punches, dropping down with an interval of 10-15 seconds and lingering at the bottom for no more than 1 - 2 seconds, cover the holes in the crust only for 16 - 36 seconds per 8 to 18 cycles. This ensures that more alumina enters the solution.

Чтобы эта реакция проходила в минимальной степени, фтористые соли вводят в отверстие дозами 0,05-0,35 кг с постоянной частотой, совпадающей с частотой пробойника, опережая начало движения пробойника "вниз" на 3-4 секунды. Такой способ снижает потери фтора на 0,2-0,5 кг/т алюминия, а также обеспечивает плавный переход на требуемое криолитовое отношение и точное его поддержание.The dose of fluoride salts should be heated as quickly as possible and enter the melt, because moisture entering the electrolyzer with raw materials and from the air reacts with fluoride salts, decomposing them at temperatures of 200-250 ^o C to gaseous hydrofluoric acid and alumina by reaction

In order to minimize this reaction, fluoride salts are introduced into the hole in doses of 0.05-0.35 kg with a constant frequency coinciding with the frequency of the punch, 3-4 seconds ahead of the punch. This method reduces the loss of fluorine by 0.2-0.5 kg / t of aluminum, and also provides a smooth transition to the desired cryolite ratio and its exact maintenance.

 Industrial applicability. The method and device can be reproduced according to the description of the invention with the achievement of a technical result on industrial electrolyzers for aluminum production using both existing automated process control systems and newly created ones, for example, the TROLL system (ToxSoft JSC, Moscow). The invention allows to provide equally high rates as when using conventional metallurgical alumina, and more expensive alumina "sand" type. In addition, the invention allows to increase the overhaul life of equipment and reduce energy costs.

Claims (7)

 1. The method of supplying aluminum electrolyzer with alumina and corrective additives, including dosed supply of granular material from the tank into the electrolyte melt through holes in the crust formed by punches, reciprocating, and adjusting the dose of the material by means of pneumatic pulses with controlled parameters, characterized in that the holes in the crust are supported by non-fouling through the cyclic work of the punches while minimizing their time in the lower position, while creating conditions for the outflow of material into the molten electrolyte through the slit-like outlet in the side wall of the tank under the action of aerating pneumatic pulses introduced into the layer moving under the action of gravity of the material, and the material is cut off when adjusting the dose by self-locking of the said outlet holes after stopping the supply of aerating pneumatic pulses.  2. The method according to claim 1, characterized in that the time spent by the punch in its lowest position is 1 to 2 seconds.  3. The method according to claim 1 or 2, characterized in that the dose of bulk reagents is set in the range of 0.05-0.35 kg per hole, and ceteris paribus feed the electrolyzer with increased doses at those supply points where the electrolyte speed is higher .  4. The method according to any one of claims 1 to 3, characterized in that the pressure difference generated by pneumatic pulses under the gas-permeable bottom and above it is 0.05 - 2.0 kPa.  5. A device for supplying aluminum electrolyzer with alumina and corrective additives, including a hopper for bulk reagents, a dispenser with a casing, a point and means for regulating the mode of supply of reagents, a punch with a drive connected to the pneumatic impulse supply and control unit, characterized in that the means for regulation of the flow regime of bulk reagents made in the form of an aeration box with a gas-permeable element connected to a block of pneumatic pulses and control, while gas the element to be used is the bottom of the dispenser casing, the front wall of the casing is installed with a gap relative to the bottom protruding outside the casing, and together with the guide sides fastened to the casing, forms a estrus.  6. The device according to claim 5, characterized in that the aeration box with a gas-permeable element is made of heat-conducting, heat- and wear-resistant material.  7. The device according to claim 5 or 6, characterized in that the dispenser is equipped with means for measuring the angle of inclination of the dispenser body in a vertical plane.

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