Hammer mill and Ball mill

This is presentation of Pharmaceutical engineering.

1. PHARMACEUTICAL ENGINEERING (PHS-CC-3104)

2. SUBMITTED TO- DR. SANJAY KUMAR JAIN SIR DR. ASHISH JAIN SIR SUBMITTED BY- ARYA OJHA B.PHARM 3 RD SEMESTER DEPARTMENT OF PHARMACEUTICAL SCIENCES ROLL NO - Y19150014 SESSION - 2020:2021 DEPARTMENT OF PHARMACEUTICAL SCIENCES DR. HARISINGH GOUR VISHWAVIDHYALYA SAGAR, M.P. 470003

3. ACKNOWLEGEMENT I would like to thanks Pharmaceutical engineering teachers Dr.S.K JAIN SIR, DR. ASHISH JAIN SIR who gave me this opportunity to do this assignment. I pay my heartiest gratitude to my guide and other faculties who helped and supported me throughout my work.

4. TOPIC:

5. CONTENT:

6. SIZE REDUCTION Size reduction is a process of reducing large solid unit masses (chemical substances or vegetables) into small unit masses, coarse particles or fine particles. S ize reduction process is also termed as Comminution , Diminution or Pulverization .

7. SIZE REDUCTION is done by: Precipitation Method : Substance + Solvent. Then it is precipitated by addition of another solvent , which is miscible with the first , but in t he second solvent it is insoluble . Mechanical Method : In this, substance is subjected to mechanical forces using grinding equipments like (ball mill, roller mill, colloid mill, hammer mill etc.)

8. Mechanical FORCES

9. IMPACT

10. attrition

11. Mechanical Method EQUIPEMENTS USED:

12. Hammer mill: A hammer mill is essentially a steel drum containing a vertical or horizontal rotating shaft or drum on which hammers are mounted.

13. Principle- The hammer mill operates on the principle of impact between rapidly moving hammers mounted on a rotor and the powder material.

14. Constructio n -

15. The hammer mill can be either the horizontal or vertical shaft type. Hammers are usually made of hardened steels, stainless steel, with impact surface made of extremely abrasive resistant material such as haystellite and carbaloy. Stainless steel hammers are sufficient for pharmaceutical purposes.

16. The two basic shape of hammers are: STIRRUP BAR The unit is closed with a chamber containing a grid or removable screen through which material passes. Screens are prepared using metal sheets of varying thickness with perforated holes. The hammer swings on the ends or fixed to centre rotor. The material is put inside through rotor.

17. working-

18. The hammer mill are mainly operated at 8000 to 15000 rpm in continuous motion for reduction of particles. The screen in hammer mill are interchangeable so that any grade of fineness can be achieved.

19. The hammer act as a centrifugal fan so that large amount of air is drawn through the mill to counteract the heat generated during milling.

20. The finenes of the product can be regulated by altering

21. uses- Fine to moderate grinding of powders may be obtained. Non abrasive to moderately abrasive materials can be used. Used to mill : Dry materials Wet filter press cakes Ointments S lurries

22. advantages-

23. disadvantages-

24. ball mill: A  ball mill  is a type of grinder used to grind or blend materials for use in mineral dressing processes, paints, pyrotechnics, ceramics.

25. Principle- The ball mill operates on the principle of impact and attrition . Impact is between rapidly moving balls and the powder material. mounted on a rotor and the powder material. The balls roll over each other and show rubbing action, hence attrition force is also responsible for size reduction.

26. Constructio n -

27. The ball mill consists of hollow cylinder , mounted on a metallic frame so that it can be rotated on its horizontal axis. The cylinder is made of metal and usually lined with chrome (type of steel), rubber or porcelain (in pharmaceutical industry).

28. The cylinder contains grinding materials or medium called balls. They occupy 30-50% of mil volume. The ball size depends on Size of feed Diameter of mill B alls are made of steel, iron, stoneware.

29. Construction OF INDUSTRIAL BALL MILL-

30. working-

31. The mill is allowed to rotate on its longitudinal axis.

32. The correct speed of ball mill where impact and attrition acts.

33. ROLE OF SPEED IN BALL MILL . At low speed of rotation , the balls roll over each other and attrition will be a predominant mode of action. It can be used for wet grinding.

34. At high speeds , the balls are thrown out to the wall by centrifugal force. This is known as centrifuging. Hence grinding would not occur because the compression by balls against wall is not sufficient to reduce size.

35. At correct speed impact + attrition causes the size reduction. Ball mills successfully runs at speed between 60 and 90 percent of critical speed.

36. The operating speed i.e. the correct speed of ball mill must be less than critical speed. The minimum speed at which centrifuging occurs is known as critical speed. N c  is the  critical speed, in revolutions per minute, D  is the  mill  effective inside diameter, in feet. Critical Speed is: N c  =76.6(D 0.5 )

37. The finenes of the product can be regulated by altering

38. uses- Fine grinding with particle size 100 to 5 mm. Hard and abrasive materials can be used . Stainless steels balls are preferred in production of ophthalmic and parenteral products At low speed used for milling: Dyes Pigments Insecticides

39. advantages-

40. disadvantages-

41. REFERENCES: SUBRAHMANYAM C.V.S, SETTY J, SURESH S, DEVI V, “PHARMACEUTICAL ENGINEERING ( PRINCIPLES AND PRACTICES), VALLABH PRAKASHAN, 2001 , PG.NO. 153-158 . SCHLESINGER M, DAVENPORT W,” EXTRACTIVE METALLURGY OF COPPER , 5 TH EDITION, 2011 . WWW.SCIENCEDIRECT.COM