Evaporators and evaporation under reduce pressure.


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Evaporators and evaporation under reduce pressure.

  1. 1. Presentation<br />INDUSTRIAL PHARMACY<br />
  2. 2. Topic:-<br />
  3. 3. EVAPORATORS<br />
  4. 4. A Apparatus used to vaporize some part or all of the liquid from a solution is called as evaporator, and the phenomenon is known as Evaporation.<br />
  5. 5. Evaporation<br />
  6. 6. Importance of Evaporators<br />
  7. 7. <ul><li>Temperature</li></ul>  The rate of evaporation is directly proportional to the rate of temperature.<br /><ul><li> Surface area</li></ul>The rate of evaporation is directly proportional to the surface area of the vessel exposed to evaporation. <br /><ul><li> Agitation</li></li></ul><li>Selection of Evaporator<br />
  8. 8. Types of Evaporators<br />
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  11. 11. Small quantities of liquids may be evaporated in a porcelain or glass dish. Generally there are 2 different methods used in small scale evaporation.<br />Direct Heating Methods: <br />These methods are applied by Bunsen burner or electric hot plates, but it should not be employed commonly, as direct heating leads to decomposition of the substances’ towards the end of evaporation. <br />
  12. 12. 2) Indirect Heating Methods<br /> Water bath, Sand Bath and Oil bath Mainly used.<br /> A fixed maximum temperature can easily be attained by employing these apparatus.<br /> A water bath is most suitable when the liquids are to be heated up to 100°C.<br /> Sand bath or oil bath containing liquid paraffin or soft paraffin may be used when higher temperatures up to 300 °C are required. <br />
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  15. 15. 1) Evaporating pan<br />On a manufacturing scale, solutions containing water in large quantity are evaporated through open pans Called evaporating pans. They consist of hemispherical or shallow pans made of copper, stainless steel, aluminum or other metal surrounded by a steam jacket.<br />
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  18. 18. 2) Evaporating Stills:<br />Evaporating stills are quite similar to evaporating pans. It consists of a vessel made up of copper or stainless steel, with a cover which is fitted with a water condenser so that the solvent is condensed and collected in a receiver. At the lowest point of the pan, a tube fitted with a tap is connected for the removal of product from the pan. The pan is surrounded by a steam jacket. For cleaning the pan or easy removal of the product the cover of the vessel may be fitted with quick-release system of clamps.<br />
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  22. 22. 3) Calandria type Evaporator:<br />Commonly it is known as short tube or single effect evaporator.<br />Features:-<br /> Vertical type of evaporator.<br />Tubes sheets extending across the body and central down take.<br />Material which has to be evaporated is introduced in tubes.<br />The tube may be about 1.2m long and 5 cm in diameter, but the size varies with the nature of the substances.<br />There is space below containing a steam coil to give extra heating capacity and large enough to afford circulation of liquid.<br />
  23. 23. Diagram:<br />
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  27. 27. 4) Climbing film Evaporator:<br />It is also known as long tube or rising film evaporator.<br />
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  30. 30. Horizontal Film Evaporator<br />
  31. 31. 5) Horizontal Film Evaporator<br />Also known as falling film evaporator.<br />
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  35. 35. 6)Rising-falling film Evaporator:-<br />Rising and falling film evaporators are some time combined in to a same unit. When a high ratio of evaporation to feed is required and concentrated liquid is viscous, a tube bundle can be divided in to two sections with the first section functions as a rising film evaporator and the second section serves as falling film evaporator. <br />
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  38. 38. Evaporation Under Reduce Pressure<br />
  39. 39. *It is also known as Vacuum Evaporation.<br />Description:<br />Vacuum evaporation is the process of causing the pressure in a liquid-filled container to be reduced below the vapor pressure of the liquid, causing the liquid to evaporate at a lower temperature than normal. <br />When the process is applied to food and other products and the water is evaporated and removed, the food can be stored for long periods of time without spoiling. It is also used when boiling or heating a substance at normal temperatures would chemically change the consistency of the product.<br />Vacuum evaporation is used whenever possible because there is a saving of time, heat and labour.<br />
  40. 40. 1) Single-Effect Vacuum Evaporator<br />
  41. 41. Single-effect Vacuum Evaporator<br />A single effect evaporator is utilized using water as feed and condensed water and liquid water as product. This evaporator may be run with and without a vacuum at different steam pressures. Running the evaporator under a vacuum proved to be more efficient with respect to steam usage for evaporation.<br />Single-effect evaporator is discussing briefly in above heading of Calandria-type evaporator.<br />In this type of evaporator the vapor from boiling liquid is condensed and discarded.<br />
  42. 42. Diagram:<br />
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  45. 45. Triple-effect Vacuum Evaporator<br />
  46. 46. Features:<br /> This equipment adopts the principle of multitubular circulation out-heating working principle to keep the short heating time of materials, rapid evaporation speed, large concentration ratio, so that to keep the raw-effect of materials effectively.<br />Energy will be well saved 70% than single-effect evaporator. Materials are evaporated & concentrated under sealed state which is clean and comfortable. Besides, it is equipped with special foam-removing device to prevent the material running phenomenon.<br /> All the parts touched with materials are made of stainless steel and be polished. The equipment has the properties of good corrosion-proof, easy of cleaning in accordance with requirements of Pharmacy, Food Hygiene. It can be matched with PC control system and be easy of operation and stable effects.<br />
  47. 47. Diagram:<br />