402results about "Pulp beating/refining methods" patented technology

The utility model relates to the technical field of papermaking equipment, and discloses an environment-friendly and energy-saving papermaking pulping machine which comprises a base, a bearing disc is fixedly connected to the top of the base, a pulping barrel is fixedly connected to the middle of the top of the bearing disc, a supporting frame is fixedly connected to the periphery of the top of the bearing disc, and a lifting rotating mechanism is arranged on the inner side of the supporting frame. An adjusting mechanism is arranged in the pulping barrel, a pulping device is arranged at the top of the adjusting mechanism, the lifting and rotating mechanism comprises a lifting assembly and a rotating assembly, the lifting assembly is arranged on the inner side of the supporting frame, the rotating assembly is arranged at the bottom of the lifting assembly, and the lifting assembly comprises a first motor; the first motor is fixedly connected to the top of the supporting frame. The threaded rod can drive the lifting frame to drive the fixing frame to move downwards, the fixing frame can drive the first pulping disc to move downwards, the second motor drives the rotating shaft to rotate along with the first pulping disc, and the first pulping disc can conduct pulping on papermaking raw materials in the pulping barrel.

The invention discloses an chemi-mechanical pulp production method capable of improving the filtration property of chemi-mechanical pulp, and relates to the technical field of papermaking, high-concentration grinding freeness is optimized to 640 + / -30ml, pulp fine fibers can be controlled at 22%-33%, the tensile index middle-lower limit and the bulk middle-upper limit, the high-concentration grinding effect is improved, the effect between fibers is facilitated, the effect between the fibers and a grinding sheet is reduced, and the filtration property of the chemi-mechanical pulp is improved. Fiber cutting is reduced, and the content of pulp fine fibers is reduced; the MSD torque is increased to 250 + / -10 KNM, the tearing effect of wood chips is improved, the preimpregnation reaction of the wood chips is facilitated, the original fine content is controlled to 26%-29% from original 22%-33%, the pulp bulk is increased by about 0.1 cm < 3 > / g, and the tensile index is increased by 1.0 N.m / g; the four low-concentration grinders are changed into parallel connection, so that the residence time of pulp in the low-concentration grinders is prolonged, the cutting effect of the pulp ground by the low-concentration grinders on fibers is reduced, light friction between grinding sheets and the fibers is increased, fibrillation of the fibers is facilitated, the bulk and the tensile strength are improved to a certain extent, and under the content of fine fibers, the size of the fibers is reduced. And the bulkiness and the tensile index of the finished pulp are also improved to a certain extent.

The invention discloses nano cellulose with high lignin content, a preparation method thereof and application of a barrier coating. The preparation method comprises the following steps: mixing a lignocellulose raw material with dilute sulphuric acid for acid pretreatment, and selectively depolymerizing hemicellulose to obtain lignin-rich residues of which the relative content of lignin is higher than that of the raw material; and carrying out mechanical nano fibrillation treatment to obtain the high-lignin-content nano cellulose with the lignin content of 29-60%. The prepared nano cellulose with high lignin content has excellent thermal stability, hydrophobicity and organic compatibility. The surface of paper is coated with the coating material, after hot pressing treatment, the Cobb value of the coated paper is as low as 3.3 g / m < 2 >, the water vapor permeability is only 12.1 g / (m < 2 >. D), grease permeation can be completely blocked, and the coating material has wide application prospects in the field of food packaging.

The invention belongs to the technical field of mineral flotation, and particularly relates to a cellulose-based coal slime collecting agent and a preparation method and application thereof. The method comprises the following steps: performing wet grinding on recycled waste paper to obtain a paper pulp solution, stirring until paper pulp fibers are uniformly dispersed, adding excessive lithium chloride and sodium periodate, performing stirring reaction, cleaning and centrifuging to obtain precursor cellulose, performing amino alkylation modification to obtain amino alkyl cellulose, preparing the amino alkyl cellulose into a 20 g / L solution, and performing vacuum drying to obtain the lithium ion battery cathode material. And then uniformly mixing with non-polar hydrocarbon oil according to the volume ratio of 1: 2 to obtain the coal slime collecting agent. The prepared coal slime collecting agent contains the hydrophobic nanocellulose with the large length-diameter ratio, in the flotation process, adhesion of bubbles and minerals can be promoted, diffusion of the bubbles is promoted, and the flotation efficiency and the recovery rate are improved.

The utility model discloses a refined cotton pulping device, which is characterized in that a central island seat is fixedly arranged at the center of a pulping pool, an annular pulp groove is formed in the pulping pool, a pulp inlet pipe and a water inlet pipe are respectively communicated with the front side of the pulping pool, and paired first motors are respectively and fixedly arranged on the outer wall of one side of the pulping pool; the paired first lead screws are rotationally installed on the outer wall of one side of the pulping pool through rod bases respectively, the lower ends of the paired first lead screws are in transmission connection with the paired first motors respectively, threaded holes corresponding to the paired first lead screws are formed in the base, and the base is in threaded transmission connection with the paired first lead screws through the threaded holes respectively. The beating device has the advantages that pulp floating on the water surface can be quickly beaten by the aid of the beating roller, part of clustered pulp can be effectively loosened, and the beating effect is good.

The invention belongs to the technical field of pulping and papermaking, and particularly discloses a method for preparing chemimechanical pulp by dipping bamboo reed in hot alkali and a method for constructing a model of the chemimechanical pulp, and the method comprises the following steps: putting absolutely dry raw materials of the bamboo reed into a sealing bag, adding water, sealing, and carrying out high-pressure sterilization; the method comprises the following steps: carrying out extrusion defibering and hot alkali dipping on the gold arundo donax subjected to high-pressure sterilization, and then collecting a treatment solution, in the hot alkali dipping process, alkali in hot alkali liquor is NaOH, in terms of Na2O, the use amount of the alkali is 4-8%, the temperature is 90-100 DEG C, and the dipping time is 30-60 minutes; carrying out segmented pulp grinding on the residual solid; and washing the ground pulp, heating for latency elimination, screening to obtain fine pulp, and pulping to obtain the product. After appropriate hot alkali dipping, paper made of the golden reed chemimechanical pulp can be comparable with wheat straw chemimechanical pulp paper in physical performance.

The invention discloses an energy-saving pulping method based on pretreatment strengthening and segmented enzyme activation, and belongs to the technical field of pulping and papermaking. According to the pulping method provided by the invention, p-toluenesulfonic acid is added in pretreatment to adjust pH and strengthen enzyme activity, and enzyme is wrapped by using a temperature or pH response type carrier, so that pectinase, cellulase and laccase can be controlled to be released and activated in a proper treatment stage. By accurately controlling the enzyme action sequence, substrate competition is avoided, enzyme inactivation is reduced, the enzymolysis efficiency and the utilization rate are effectively improved, and the COD content of wastewater is reduced; and two-stage pulping and p-toluenesulfonic acid are combined to soften fibers synergistically, so that the power consumption per ton of pulp is reduced. According to the invention, fiber fibrillation is promoted through enzyme treatment, and the tensile strength and the water retention value are effectively improved; the laccase catalyzes crosslinking of lignin, so that the wet strength is remarkably improved. The paper pulp provided by the invention gives consideration to physical properties and environmental protection requirements of high-strength packaging paper manufacturing, and has a wide application prospect.

The invention discloses high-strength high-air-permeability germinable seed paper and a preparation method thereof, and belongs to the technical field of seed paper preparation. The technical problem that the water absorption and air permeability of traditional seed paper are reduced due to addition of a chemical reinforcing agent, and then the germination rate of seeds is affected is solved. According to the technical scheme, unbleached softwood pulp is used as a raw material, after being pulped by a PFI mill, the unbleached softwood pulp is mixed with cationic lignocellulose nanofibrils and seeds which account for 4-8% of the mass of absolute dry pulp for pulping, forming is conducted through an automatic paper making system of a Kaiser method, and drying and shaping are conducted at the temperature of 40 DEG C; the cationic lignocellulose nanofibrils are prepared by the steps of grinding unbleached softwood pulp, performing alkali treatment, performing etherification reaction and performing ultrahigh-pressure homogenization. The seed paper does not need a chemical reinforcing agent, the air permeability is 17.4-18.8 [mu] m / (Pa.S), the tensile strength is 6.08-6.84 kN / m, and the relative absorptivity is 214-230%.

The invention discloses a preparation method of degradable napkin based on natural plant fibers, and relates to the field of hygienic products. According to the preparation method of the degradable napkin based on the natural plant fibers, natural cellulose raw materials such as the sisal hemp waste residues and the banana stalks are adopted, the source is wide, and the cost is low. Raw materials are cleaned, crushed and degummed to prepare crude fiber bundles, and the crude fiber bundles are converted into soft microfibrillated cellulose colloid through enzyme treatment. Defibering part of the colloid into long-fiber matrix pulp, homogenizing the other part of the colloid at high pressure to prepare short-fiber reinforced pulp, mixing the long-fiber matrix pulp and the short-fiber reinforced pulp to obtain reinforced pulp, and performing papermaking, drying and calendering to prepare the raw paper. According to the process, through fiber softening treatment, the softness and hand feeling of the paper are remarkably improved while the toughness is kept, and the process is suitable for napkin production. A green biotechnology is adopted in the whole process, the pollution load is low, chemicals are biodegradable, and the requirements for low cost and environmental protection are met.

The invention discloses a carbon fiber paper-based material and a continuous calendering enhancement method thereof. The preparation method specifically comprises the following steps: repulping, grinding, defibering and sieving meta-aramid pulp, and then mixing with defibered and dispersed short carbon fibers to prepare paper pulp; sequentially carrying out forming, dewatering, squeezing and drying treatment on the slurry to obtain a carbon fiber base paper coiled material; and carrying out continuous calendaring enhancement treatment on the carbon fiber raw paper coiled material to obtain the carbon fiber paper. According to the method, the purpose that the temperature is higher than the glass transition temperature (larger than or equal to 273 DEG C) of the meta-aramid pulp can be achieved, the purpose of conducting hot pressing on the carbon fiber base paper can be achieved, the large-batch and continuous production requirements of the carbon fiber paper can be met, and the production efficiency is greatly improved.

A defibering and deflaking pulper has a defibering rotor-stator pair and a deflaking rotor-stator pair for processing a fiber-based material into smaller pieces. The defibering and deflaking pulper creates an impeller-produced vortical circulation that pulls the material through a defibering rotor-stator interface, where the material is broken down into smaller pieces, and then through a deflaking rotor-stator interface, where the smaller pieces are broken down into even smaller pieces. The defibering and deflaking pulper accumulates the defibered and deflaked material that passes through the defibering rotor-stator interface and the deflaking rotor-stator interface for further processing. This combination of defibering and deflaking in the defibering and deflaking pulper reduces plugging from larger pieces of the material and reduces downstream processing of the material, thus increasing productivity and reducing costs.

The application discloses a kind of aerodynamic feed dual-disc refiner, including machine body, casing, machine cover, rotating disc, fixed disc, casing is connected with machine body, machine cover, inlet two, discharge port are equipped on casing, fixed disc includes fixed disc one, fixed disc two, spring return device includes spring return device one, spring return device two, fixed disc one is connected with spring return device one, fixed disc two is connected with spring return device two, spring return device one is connected with machine cover, spring return device two is connected with casing, casing and machine cover form airtight refiner chamber, rotating disc is connected with main shaft, machine cover is equipped with air inlet one, drain one, casing is equipped with air inlet two, drain two, fixed disc one and machine cover form air chamber one, fixed disc two and casing form air chamber two, air chamber one, air chamber two are connected with gas source, the present application pressure and pulp pressure self-balancing ensure that the gap of two sides of grinding piece is consistent, force is same, output pulp beating degree is consistent, pulp quality is good, prolongs the service life of grinding piece, reduces use cost.

A method of refining dense pulp comprising the steps of prearranging a stator (10) having a perforated side wall (11), prearranging a rotor (20) rotatable in the stator (10), said rotor (20) comprising a plurality of blades (21) having respective cutting profiles (22) arranged at a distance d from the perforated side wall (11), said rotor arranged to be rotated at a peripheral speed v of the cutting profiles (22) with respect to the stator (10). The method then comprises the steps of prearranging in the stator (10) an inlet duct (15) and prearranging externally to the stator (10) a collection chamber (30) having an outlet duct (31). The method also comprises a step of feeding into the stator (10), through the inlet duct (15), selected pulp previously subjected to separation from solid parts, so that the blades (21) cause the forced passage of the selected pulp between the cutting profiles (22) of the blades (21) and the perforated side wall (11), causing a refining action of the selected pulp, and so that refined fibers pass through the perforated side wall (11) and reach the collection chamber (30) and the outlet duct (31).

According to an exemplary embodiment of the present invention, a method is provided that includes providing a pulp composition, screening the pulp composition to obtain an accept fraction and a reject fraction, and dewatering the accept fraction output from the screening by a screw press.

The invention relates to a milling element (2) for a refiner. Milling strips (21) are arranged on a base plate (18) of the milling element (2). Adjacent milling strips (21) form grooves (22) extending between the milling strips (21). A hydraulic capacity is provided by the open area of the grooves in the peripheral direction. The height of the milling strips above the base plate (18) decreases from radially inwards to radially outwards, wherein, at a predetermined partial height, the open area of the grooves at the partial height at the inner radius approximately corresponds to the open area of the grooves at the partial height at the outer radius. The partial height is obtained by shortening all milling strips (21) by a predetermined amount (27).

Textile fibers of different lengths are fractionated in a liquid medium at a predetermined consistency into at least two fractions on the grounds of the fiber length, the two fractions being a first accept and a second accept. The second accept, which has longer fibers than the first accept, is led to a refining step in the liquid medium, and the refined fibers are fractionated in the liquid medium into at least two fractions on the grounds of the fiber length.

There is provided a bleached high temperature chemithermomechanical pulp and a method for producing said HT-CTMP comprising the steps: a) providing wood chips comprising softwood, hardwood or mixtures thereof; b) impregnating the wood chips with an impregnation liquid comprising NaOH and / or Na2SO3 to obtain impregnated chips; c) transferring the impregnated chips to a heating zone without compressing the impregnated chips; d) heating the impregnated chips in the heating zone with steam having a temperature of above 140 °C, such as at least 150 °C, such as at least 160 °C, to obtain pre-treated chips; e) defibrating the pre-treated chips to obtain a pulp; f) bleaching the pulp to obtain a bleached pulp; and g) refining the bleached pulp at a consistency of 3-8 wt. % to obtain bleached HT-CTMP.

The utility model provides bamboo pulp unbleached paper pulping equipment which comprises a processing box with one side in an opening shape, a rotating shaft driven by a motor is movably arranged in the processing box, a supporting seat is fixed to the bottom of the rotating shaft, two connecting frames are fixed to the bottom of the supporting seat at intervals, and mounting frames are fixed to the bottoms of the connecting frames. A first mounting shaft is movably arranged on the mounting frame, two pulping discs are mounted on the first mounting shaft at an interval, second mounting shafts are movably arranged on the two connecting frames, chain wheels are mounted on the first mounting shaft and the second mounting shafts, and a supporting shaft is fixed in the treatment box; according to the bamboo grinding machine, the problem that in the pulping process, due to the fact that bamboo fibers are long, a traditional grinding machine needs to spend much time to complete pulping is solved.

The embodiment of the invention provides a preparation method of cotton-feeling household paper, which comprises the following steps: providing long fibers and short fibers in a specific ratio, and controlling the dry weight ratio of bamboo pulp in mixed pulp to be 20-40%; the pulp is subjected to tandem type two-stage pulp grinding treatment, the specific energy consumption of the first stage is 30-50 kWh / adt, and the specific energy consumption of the second stage is 150-170 kWh / adt; sequentially adding a wet strength agent and a softening agent; and finally, forming, squeezing, drying and carrying out wrinkling treatment with the wrinkling rate of 22-26% to obtain the raw paper, through cooperation of the processes, the problem that high wet strength and high softness of the bamboo-based household paper are difficult to consider at the same time is solved, the wet-to-dry ratio of the prepared product is larger than or equal to 32%, the softness is smaller than or equal to 110 mN, and the product has the wet durability of cotton-like soft towels and the softness of high-end household paper.

A refiner disc of a refiner (100) for refining of lignocellulosic material, said refiner disc (30) having an active surface (1; 1') comprising a pattern of bars (10) and grooves (20) disposed in a number of pattern areas (41; 41'), wherein said pattern areas (41; 41') are positioned side by side with each other to cover at least a part of the active surface (1; 1'). Each of said pattern areas (41; 41') has a length, l, extending between a first end (43a) and a second end (43b) of the pattern area (41; 41') and a width, w, extending between two side edges (45a, 45b) of the pattern area, wherein a distance between the two side edges (45a, 45b) is smallest in the first end (43a) of the pattern area (41; 41') and is increasing towards the second end (43b) of the pattern area. Each of said pattern areas (41; 41') is positioned on the active surface (1; 1') such that a centre line, c, of the pattern area (41; 41') is provided at an angle, p, to a radius, R, of the refiner disc (30), said angle, p, being between 10-60°.

The utility model relates to a paper pulp production system capable of recycling white water, which comprises a white water tank, an air floatation device, a short fiber defibering pipeline, a long fiber grinding pipeline and a sizing pipeline, and the tail ends of the short fiber defibering pipeline and the long fiber grinding pipeline are respectively converged to the sizing pipeline; an outlet of the white water tank is respectively connected with the first centrifugal pump and the second centrifugal pump; the first centrifugal pump is respectively connected with the short fiber defibering pipeline and the long fiber grinding pipeline and is used for respectively conveying white water in the white water tank into the short fiber defibering pipeline and the long fiber grinding pipeline; an outlet of the second centrifugal pump is respectively connected with the air floatation device and the sizing pipeline and is used for respectively conveying the white water in the white water tank into the air floatation device and the sizing pipeline. Compared with the prior art, the white water in the white water tank can be conveyed into the short fiber defibering pipeline, the long fiber pulping pipeline and the sizing pipeline, so that the white water can be recycled in the whole paper production system.

The invention discloses high-smoothness paper for daily use and a preparation method thereof. The method comprises the following steps: applying a cationic softening agent (the addition amount is 0.8%-1.2%) to paper pulp fibers, and carrying out physical swelling treatment (0.15-0.20 MPa, 20-30 minutes); then grinding under the power of 280-310 kW, and controlling the concentration to be 3.5%-4.0%; and finally, forming on a 120-140-mesh forming net under the calendering pressure of 0.25-0.30 MPa, drying at the temperature of 110-120 DEG C for 15-20 seconds, and wrinkling. An on-line detection and feedback system can be integrated, and key parameters can be dynamically adjusted. The softness of the prepared household paper is 6.0-8.0 mN, the smoothness is 45-55 s, the wrinkle depth deviation is less than or equal to 0.02 mm, and the raw materials are hardwood pulp and softwood pulp in a ratio of 8.5: 1.5. According to the scheme, unification of softness, smoothness and high strength is achieved, the problems of performance contradiction and unstable production in a traditional process are solved, and the method is suitable for continuous intelligent manufacturing of high-end household paper.

This invention discloses a method for preparing zero-VOCs degradable seedling paper, comprising the following steps: S1, raw material selection: the fiber raw material includes 75-85% cattail and 15-25% reed by mass fraction; S2, the fiber raw material described in S1 is sequentially processed through the following steps: cattail + reed → vertical cooking → closed screening → pulp washing → oxygen delignification → pulp concentration → unbleached chemical straw pulp → storage tower → extruder → high-consistency mill → anti-fouling tank → conical refiner → pulp mixing tank → pulp forming tank → sand removal → screening → wire forming → pressing → pre-drying → surface sizing → post-drying → calendering, to obtain seedling paper that meets the requirements for ecological agricultural paper. The seedling paper obtained by this invention has good air permeability and high dry and wet strength, weather resistance to wind and rain erosion and trampling, can achieve natural microbial degradation in soil, and all raw materials are zero-VOCs degradable and sustainable, making it green, environmentally friendly and harmless to the soil.

The utility model relates to a series pulping machine, and relates to the technical field of papermaking equipment, the series pulping machine comprises a rack, the rack is provided with a feeding barrel, a first pulping machine, a second pulping machine and a third pulping machine, and the rack is also provided with a conveying device and a bearing device. According to the pulping device, the first pulping machine, the second pulping machine and the third pulping machine are installed on the rack, the feeding barrel sequentially feeds pulp into the first pulping machine, the second pulping machine and the third pulping machine through the conveying device, and the receiving device receives pulp water produced by the first pulping machine, the second pulping machine and the third pulping machine; therefore, the continuous production of the slurry from coarse grinding to fine grinding is realized in a manner that the slurry is sequentially treated by the first pulping machine, the second pulping machine and the third pulping machine, and the production efficiency and the product quality are improved.

The application relates to the papermaking technical field, and discloses a reusable ultrahigh-purity paper and a preparation method thereof.A preparation method of a reusable ultrahigh-purity paper comprises the following steps: taking high-purity cellulose pulp plates, dispersing the high-purity cellulose pulp plates in deionized water, and then performing a deconstruction treatment to prepare paper pulp; performing ultrasonic treatment on the paper pulp in an acid medium, and then performing ultrasonic treatment on the paper pulp in ethanol to prepare purified paper pulp; washing the purified paper pulp with deionized water; obtaining original paper through self-assembly forming and drying treatment of the washed paper pulp; coating resin on the surface of the original paper; performing hot-pressing treatment and corona treatment on the original paper coated with the resin, and then performing high-temperature treatment and packaging to obtain the reusable ultrahigh-purity paper.The preparation method is simple in operation, high in production efficiency, and meets the environmental protection requirements; the prepared ultrahigh-purity paper is high in purity, low in impurity content, and can meet the demand of sampling paper.

The invention belongs to the technical field of papermaking, and particularly relates to a process for improving blister fastness of a blister card. Comprising the following steps: treating needle and hardwood pulp with compound enzyme, adding light magnesium oxide, grinding to obtain compound modified pulp, preparing three layers of pulp, diluting and purifying, adding auxiliaries into a three-layer slushing pump before purifying, and adding core layer auxiliaries containing hydroxymethyl urea modified cationic polysaccharide and the like into a core layer pump; the three layers of pulp are compounded into a wet paper web layer by layer through an upper net of a headbox, gradient pre-drying is performed after multiple times of squeezing dehydration, and then surface sizing, post-drying, hard calendaring, front and back coating and soft calendaring are performed in sequence to obtain a finished blister card product. The process effectively solves the problems of infirm blister and shelling in narrow-edge blister processing, realizes standardized control of slurry quality, greatly reduces batch-to-batch difference of blister effects, remarkably improves the binding force of a narrow-edge blister area, optimizes the surface performance of paper, reduces the phenomena of linting and powdering during printing, and improves the printing quality of the narrow-edge blister blister. And the printing adaptability is improved.

There is provided a method of producing a highly refined pulp, comprising the steps of: - providing a pulp; - subjecting the pulp to a first conical refining step in at least one conical refiner comprising refining plates having a bar width of 0.5-1.5 mm, such as about 1.0 mm, and a groove width of 1.0-2.0 mm, such as 1.4-2.0 mm, such as about 1.6 mm; and - subjecting the pulp from the first conical refining step to a second conical refining step in at least one conical refiner comprising refining plates having a bar width of 0.5-1.5 mm, such as about 1.0 mm, and a groove width of 0.8-1.6 mm, such as 1.0-1.5 mm, to obtain the highly refined pulp.

The invention discloses a method for improving evenness of two-side offset paper, and relates to the technical field of papermaking, the freeness of each sizing agent is accurately controlled, and a mixed sizing agent ratio is adopted; a ternary retention system is adopted, and cationic polyacrylamide, anionic polyacrylamide and silica sol are added; a forming net is adopted, uniform fiber distribution is promoted by delaying the dehydration speed, and meanwhile the speed of a paper machine is stably controlled to avoid speed fluctuation; squeezing, pre-baking, sizing, post-baking and calendaring; and a coiling process. The method is suitable for the production and manufacturing process of the two-side offset paper, the produced two-side offset paper can be widely applied to multiple scenes such as printing and writing, and the problems that in existing two-side offset paper production, the uniformity index is low, the product quality consistency is poor, fibers are prone to flocculation to form pulp balls in the production process, the paper structure uniformity is affected, the unit consumption of chemicals is too high, and the production cost is low are solved. Therefore, the problems of high production cost, insufficient operation stability of a paper machine, large fluctuation of technological parameters and the like are solved.

The invention relates to a cyclone separator for separating fiber material from a fiber material-steam mixture, to a system for processing fiber material, and to a method for operating a cyclone separator, wherein the cyclone separator is designed such that a discharge of fiber material via a fiber material outlet and a co-discharge of steam via the fiber material outlet can be controlled in an improved manner. By means of a conical element which fits in the outlet space which correspondingly widens conically toward the fiber material outlet, the gap width of the annular gap between the conical element and the outlet space inner wall, which circumferentially delimits the outlet space, can be adjusted very simply via a relative movement between the conical element and the outlet end portion.