Wet Milling Runner Drawings with Drawings and Explanations

MINISTRY OF EDUCATION AND SCIENCE OF THE RUSSIAN FEDERATION Federal State Budgetary Educational Institution of Higher Education "Tyumen State Oil and Gas University" Transport Institute Department "Transport and Technological Systems" Coursework Performed by student: gr. MOPb - 13 Ivantsov V.S. Checked: Kostyrchenko V.A. A. General information and classification of runners 2. Design, operation and description of the processes occurring in machine 3. Technical characteristics and calculation of the main parameters Conclusion List of the used literature Introduction The variety of crushed materials according to their properties and the industrial objectives of this process leads to a large number of different structures of crushing machines and plants. All used machines for grinding materials are divided into two groups: crushers and mills. Crushers are machines that are used to crush relatively large pieces of material, the initial size is 100-1200 mm, the size of the pieces of the final product is 250-3 mm. Crushers are used in mining, mining, construction, chemical and other industries to large, average and small crushing of various rocks. Degree of grinding in crushers is within 3-20. Mills are intended to produce finely divided powdered material. They are used in rough, thin and ultra-thin grinding of limestone, chalk, marble, clay, coal, clinker and other materials, while the size of the initial pieces is 2-20 mm, and the particle size of the final product is from 0.1-0.3 mm to a fraction of a micrometer. According to the design and principle of action, the following types of crushers differ: cheek (crushing occurs between movable and fixed cheeks), cone (crushing of material and partial bending of it occurs between two cones), roll (material is crushed between two rolls rotating towards each other), runners (crushing of material occurs between rotating rollers and bowls (movable or fixed) by crushing, crushing and crushing. Compared to other grinding machines such as roller crushers, runners are generally less efficient. Therefore, they should be used only when this is caused by special technological requirements, when, along with grinding, it is necessary to provide compaction, rubbing, de-airing of the mass (for example, when processing clay). 1. The general information and classification of runners Runners are classified according to the following main features. By the method of action: periodic and continuous. By technological purpose: for wet, dry and semi-dry grinding; for crushing and hashing and only hashing; for briquetting the crude mixture; with metal rollers and metal hearth; with stone rollers and stone hearth. According to the design: with a fixed bowl; with rotating; with the upper and lower drive (disassembly is more difficult with the lower drive, repair is longer, but the mass is not contaminated); with rollers resting on the material with their mass or with additional hydraulic, pneumatic or spring pressing on the rollers. According to the unloading method: with manual unloading; forcing through the bottom grill; with centrifugal unloading; with unloading through the peripheral bottom grid and with unloading along the dump descending into the bowl. In runners with rotating rollers around the vertical axis, centrifugal forces tend to tear the rollers, and if they are unbalanced, the vertical shaft can bend, but centrifugal forces do not affect the material in the bowl. Runners with a rotating bowl have a calmer stroke, but centrifugal forces throw material to the periphery, in addition, these runners have a large load on the thrust bearing (the weights of the rollers and bowls).The advantages of runners compared to roller crushers: you can load significantly large pieces of material; it is easier to adjust the fineness of grinding; improved plastic properties of clay materials due to multiple impact of rollers. Disadvantages of runners: bulky; more complex repairs; increased specific energy consumption per unit mass of processed material. 2. The design, principle of operation and description of the processes taking place in the machine Wet milling runners (material with humidity of more than 15%) with rotating rollers (Fig. 1) have a lower drive arrangement. During rotation of vertical shaft 1, rollers 5 installed on bearings on carriers 6 roll over tray 4 and simultaneously rotate around their own axes. Crankshafts hinged in trunnion 7 allow rollers to rise or drop depending on thickness of material layer and to overcome underexplained objects. The rollers are installed at different radii from the center of the tray so that they cover a large area. The pallet is laid with plates having oval holes ranging in size from 6 × 30 to 12 × 40 mm. The ground material is forced through the holes in the tray and enters the rotating tray 8, from which it is discharged by the scraper 3 into the discharge tray 2. Links with scrapers 9 are attached to shaft 1, which clean sides and surface of cup from adhered material and guide it uniformly under rollers. Figure 1 Upper drive of rollers, runners with rotating bowl, runners with spring, hydraulic or pneumatic pressing of rollers are also used. The use of the latter allows to reduce the metal consumption of the machine. In runners, massive rollers, rolling over a layer of material located on a pallet, are crushed by crushing and abrasion. This is due to the fact that the wide rollers, moving around a circle of a small radius, continuously unfold relative to the tray and their outer side slides with a yuse, and the inner buckle. In runners, both dry and wet grinding of materials can be carried out. The main parameter of runners is the diameter D and the width b of the rollers. For wet milling, runners with dimensions D x b from 1200 x 300 to 1800 x 800 mm with rollers weighing, respectively 2... 9 t. For dry milling, runners with D x b from 600 x 200 to 1800 x 450 mm are made. Wet milling runners SM - 365 are designed for fine grinding, mixing, rubbing and moistening ceramic mixtures. The cast iron ring of the bed consists of six sections bolted together. The steel cast bowl of runners, fortified on the bed, has the shape of a truncated cone expanding to the top. The bowl casting is made without a bottom, the bottom is segmented hole plates that form a path along which the rollers roll. The material to be processed is loaded into the loading funnel, and then through the stream it falls under the roller, is crushed and abraded. Further, the material is pushed through the holes of lattice plates and wakes up under the bowl onto the plate, from which it is discharged to the stream for crushed material. The holes in the hole plates are conical, increasing to the bottom to ensure the free spill of pieces of material pushed into the holes. On the vertical shaft of runners there is a cross with horizontal semi-axes on which the rollers rotate. Rollers for more efficient grinding are equipped with special spring clamps. Adjustment nuts are provided for adjustment of roller pressing force. Runners' rollers consist of two parts: a cast-iron hull and a steel band firmly fitted on it. Runners receive motion from electric motor through friction clutch, reduction gear, horizontal drive shaft with bevel gear. Bevel wheel engaged with gear is fitted on vertical shaft. For uniformity of loading runners are equipped with rotating loading funnel. 3.Technical Characteristics and Calculation of Main Parameters Roller Sizes, Roller Pressure Force (in operation), Vertical Shaft Rotation Speed, Recycled Material Humidity, Raw Material Capacity, Electric Motor Power, Grid Hole Sizes, Runner Weight without Electric Motor, Overall Dimensions: 1800x800 mm 90 kV 22.7 rpm Clay 16-20% 43 t/h 80 kW 16x50 mm 32700 kg height 4250 mm length 6700 mm width 3350 mm 1) Determination of grip angle. The angle of capture is called the angle formed by the plane of the bowl and tangents drawn through the points of contact of a piece of material with the surface of the roller. Figure 2 At the moment of material piece gripping at point A, the force of normal pressure P and force F = P· f occur, where f is friction coefficient (Fig.2, diagram a). Resistance force P1 and friction force P1· f also occur. At balance of a piece we have: ∑x=0, P · sinα are P · f · cosα - P1 · f=0, P · sinα = P1 · f + P · f · cosα ∑y=0, P1 is P · f · sinα is P · cosα P1 = P · f · sinα + Is received by P · cosα: P · sinα=f · P · cosα + f · P · (cosα + fsinα). (1) tgα = 2· f/( 1 - f2) We substitute the value of the friction coefficient f = tg2 The friction angle: tgα = 2tg a/( 1 - tg2 a) = tg2 a (2) α < 2 a (3) Therefore, the capture angle must be less than the double friction angle. The coefficient of friction can range from 0.3 to 0.5, which corresponds to a grip angle of 30 to 50 ˚. 2) Determination of the relations between the diameter of the runner's rink and the diameter of the material to be crushed (Fig.2, diagram b). D2-d2 = D2 + d2· cosα, (4) where D is the diameter of the roller, d is the diameter of a piece of crushed material. D = d· 1 + cosα1-cosα (5) At an angle α = 50˚ we obtain: D=d·1+cos50˚1-cos50˚=4,6d At an angle α = 30˚: D=d·1+cos30˚1-cos30˚=14d D = (4.6... 14) d. (6) At D = 1800 mm, the possible size of the material to be crushed is dmax = 18004.6... 14 = 391... 128 mm. When processing wet clays, the ratio D/d is 5... 6, therefore for runners SM - 365 the maximum size of the starting material is: dmax = 18005... 6 = 360... 300 mm. To ensure reliable capture of the material, the maximum size of the pieces is taken 20% less. d = 0, 8· dmax = 0, 8· (360... 300) = 288... 240 mm. 3) The force of normal pressure acting on the material (crushing force), H: Psr = αsg· F· Knr (7) where οsg is the ultimate compressive strength of the material, N/m2, for soft rocks αsg = 80MPa, for strong αsg ≥ 150MPa (1 N/m2 = 10-6 MPa); F - crushing area, m2; Ketais the loosening factor of the material (for strong rocks Ksound= 0.2... 0.3, for clay Ka = 0.4... 0,6). Assuming that F = b· l = b· R· β, where l is the arc length in the material grinding area, m; R = D/2 - roller radius, m; b - width of rinks, m; β-arc angle, rad, β = α/2. Formula (7) takes the following form When crushing hard rocks (β = 16 ° 40 "): Psr = 0.04· αcg· b· D, (8) when crushing clays (β = 24 ° 20"): Psr = 0.1· οcg· b· D (9) For runners SM - 365: οcg = 80 MPa = 800000 N. B = 0.8 D = 1.8 m Psr = 0, 1· 8000000· 0, 8· 1.8 = 152000 N. 4) Determination of angular speed and number of revolutions of runners vertical shaft. On a rotating bowl, the material is under the influence of two forces: the friction force G· f holding the material on the bowl, and the centrifugal force mdonbass 2· mv2r striving to discard the material (where r is the outer rolling radius of the roller; [omega] is the rotational angular velocity of the vertical shaft; v - linear velocity.). So that the material is not discarded to the side of the bowl, the condition must be met: Gf≥ m· ¼ 2· r; Gf ≥ m · v2/r, where ω - the angular speed of rotation of a vertical shaft; m=G/g; v=π· r· n/30. Then: Gf≥Gg· ¼ 2· r; Gf≥π2·r2·n2g·302·r, where n is the shaft speed. ω≤f·gr (rad/s); (10) n≤30f/r (rpm). (11) Taking for humidified clays f = 0.5, we get: Angular speed of rotation of the vertical shaft: ω≤0,5· 9.81.3 = 2.4 rad/s Shaft speed: n≤300,51,3 = 23.3 rpm. 5) Determination of runners performance.For approximate calculation of productivity of runners with trellised then use the following formula: Q = S · l · a · ω\· λ2 · π (m3/s); (12) Q = S· l· a· n· 60· a (m3/h); (13) where S is the area of the hole in the lattice plate, m2; l is the length of the clay bar, m, pushed at each run of the roller (l = 25-35 mm for clays with a humidity of 20-22%); a is the number of holes covered by the roller per one revolution of the vertical shaft; [omega] is the angular velocity of the vertical shaft, rad/s; n - vertical shaft speed, rpm; ? - correction factor,? = 0.8 - 0.9. Initial data for wet runners SM - 365: S = 34· 2· 8 + 2eta· 822 = 745 mm2 = 0.000745 m2; a = 920; l = 30mm = 0.03m; λ = 0,8; n = 22.7 rpm Q = 0.000745· 0.03· 920· 22.7· 60· 0.8 = 22.4 m3/h. With clay density (humidity 20%) γ = 1450 kg/m3, we obtain: Q = 22.4· 1450 = 38480 kg/h = 38.4 t/h. 6) Determination of engine power. The engine power can be defined as the sum of the power required mainly to overcome the rolling friction and sliding friction forces of the rollers. N = (N1 + N2 )/?, (14) where N1 is the power required to overcome the rolling friction forces; N2 is the power required to overcome the sliding friction forces of the rollers. η - installation efficiency, η = 0.5 - 0.8. Power required to overcome rolling friction forces N1 = G· fk· VcpR· 1000 (kW), (15) where G is the weight (gravity of the roller), H; fk - rolling friction coefficient; vcp is the average circumferential rolling speed of the roller, m/s: R is the radius of the roller, m. Substituting in the formula the value of the average circumferential speed of vcp = pi· r· n/30, we obtain N1 = G· fk· ω· r· iR· 1000; (16) N1 = G· fk· sound· rcp· n· iR 1000· 30 = G· fk· r· n· i9554· R (kW), (17) where i is the number of rollers. Initial data: G = 90,000 N; fk = 0,03; r = 0.9 m; n = 22.7 rpm; i = 2; R = 0.9 m. N1 = 90000· 0.03· 22.7· 0.9· 29554· 0.9 = 12.8 kW. Power required to overcome the sliding friction forces of rollers: N2 = ω· b· G· fsk· i4000 (kW); (18) N2 = i· n· G· b· fsk· i30· 4000 = n· G· b· fsk· i38216 (kW), (19) where fsk is the coefficient of sliding friction; b is the width of the roller. For runners SM - 365: fsk = 0.3; b = 0.8 m. N2 = 90000· 0.3· 0.8· 22.7· 238216 = 25.7 kW. Required motor power: N = kN·G·n·iη· r· fk9554 R + b· fk38216, (20) where kN is the engine power factor to overcome the starting moment, kN = 1.1 - 1.5. N = 1, 190,000· 22, 7· 20, 7· 0, 9· 0, 039554· 0.9 + 0, 8· 0,338216 = 60.48 kW. Conclusion As a result of the calculations, the following dependencies were revealed: 1) With an increase in the rotational speed of the vertical shaft, the productivity of runners increases; 2) With an increase in the shaft speed, the engine power increases; 3) With an increase in the number of holes in lattice plates, productivity increases; 4) With the increase of the roller pressure force per ground material, the engine power increases. List of literature 1. Shoemakers V.A. and others. "Mechanical equipment of construction materials, products and structures." M., "Higher School." 1971. – 382 pages 2. Ilyevich A.P. "Machines and equipment for ceramics and refractory plants." M., "Higher School," 1979. – 343 pages 3. Shoemakers N. Ya. "Atlas of mechanical equipment" 4. Uvarov V.A., Semikopenko I.A., Chemerichko G.I., "Processes in the production of building materials and products." BelGTASM, 2002. – 121 pages.