Note s4

Milling ⬇️💕.

💠لشنو أصنف Milling equipment؟
coarse, intermediate and fine حسب حجم البرودكت النهائي

💠شلون اعبر عن Size ؟ ب مصطلح mesh

💠Hammer mill used for = granulation (16-mesh) + crystalline API to a 120- mesh powder).

💠خلو بالكم كلما اقلل الحجم حتزداد المساحة السطحية وهالشي يفيدني ب Dissolution ، Extraction، Drying

💠compressed tablet by = wet granulation = sieving of the wet mass is done to ensure more rapid and uniform drying

💠بشنو تتأثر Flowability ؟
particle size and size distribution.

💠freely flowing powders and granules = high-speed filling = produce a uniform product.

💠شلون اوحد اللون لل Solid واضمن ميصير mottled ؟
اسوي milled

💠Lubricants = essential for fine particle size

💠شلون اقلل sedimentation rate ب suspensions and emulsions ؟
اسوي milling علمود اقلل حجم البارتكل

💠milling of solid incorporated in ointments, creams, and pastes = mooth texture and better appearance

💠Term irregular particle = quivalent sphere in mathematical

💠Hooke‟s law = initial linear = stress directly o strain

💠Young‟s modulus = slope of the linear = expresses the stiffness or softness of a solid in dynes per square centimeter

💠yield poin= nonlinear= measure of the resistance to permanent deformation

💠irreversible= plastic deformation

💠area under the curv= represents the energy and impact strength

💠milling is = random matter

💠size of the finer particle = related to the internal structure

💠size of the larger particles= closely related to the process

💠اذا الطحن ماعبر elastic حيصير كسر ؟
لا وأول مااشيل السترس حترجع بارتكل لنفس شكلة والطاقة الي سلطتها حتطلع ع شكل حرارة

💠واذا عبر elastic؟
راح يصير كسر والطاقة الي سلطتها ع الاسطح الجديدة حتطلع ع شكل stress energy

💠خلو بالكم milling يتناسب طردي وي length of new cracks
وال strain يتناسب طردي وي length of the crack علمود يسوي كسر

💠شلون احول الفطر لكسر ؟
surrounding residual strain energy to the crack

💠Cutting(shearing) = application of force over a very narrow area = for fibrous materials

💠Compression= pressure between the two surfaces

💠Impact= fast moving part = causes creation of internal stresses in particles

💠Attrition= by pressure as in compression and surfaces are moving

💠شنو اهم ثلاث شغلات لازم تتوفر منو اسوي طحن ؟
feed chute ، grinding mechanism ، discharge chute

💠open-circuit milling. = passing it once through the mill,

💠closed circuit mill = passed through a size-separation device or classifier, and the oversize particles are returned to
the grinding chamber for further reduction of size.

💠إذا أريد fine and ultrafine ياطريقة استخدم ؟ Closed-circuit

هسه الاجهزه

💠Cutter Mill = mechanisms cutting or shearing = used for tough, fibrous materials

💠شنو الميكانزم مال ROLLER MILL ؟ compression and shearing

💠شلون تشتغل rolls الثانية ؟ by friction

💠لشنو تستخدم Roll ؟ احفظوها بكلمة sop يعني ointments, pastes and suspension

💠ياميكانيزم آستخدم إذا أريد اقلل حجم البارتكل ب roll ؟ attrition

💠Hammer Mill = mechanisms impact

💠منو يشتغل closed circuit ؟ Hammer اكثر شي و cutter

💠علشنو يعتمد تقليل حجم البارتكل بالهمر؟
milling tool selected , rotor speed , solid feed rate

💠شنو اهم processing بالهمر ؟
hammer tip speed and hammer mill screen size.

💠منو يولد narrow size distribution ؟ hammer mill

💠شلون احصل ع ultrafine particles بالهمر ؟
استخدم internal (build in) or external classification (added screen)

💠منو يكون closed system واستخدمة يقلل dust و explosion hazards ؟
hammer mill

Disadvantages مال همر مهمة شوفوها 💠

💠منو يشتغل گ grinding medium ب Ball Mill ؟
balls of steel or pebble

💠شلون احمي balls ؟ covered with a coarse screen

💠شنو ميكانيزم الي يشتغل بيها ball اذا جان low speed ؟ attrition
واذا جان high speed ؟ impact وهو المسؤول عن تقليل الحجم مال بارتكل

💠شنو factor المهمة ب ball mill ؟ speed of rotation اذا جان عندي:

At low angular velocities = size reduction is minimal

At high angular velocities = by centrifugal force and no size reduction occurs

about two-thirds of the critical angula = combined effect and get good milling

💠منو اكدر استخدمة لل explosive materials و ophthalmic susp. and parenter الي يكون ستريل ؟ ball mill

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