Air handling systems new

1. Mallareddy college of Pharmacy AIR HANDLING SYSTEMS guided by : Presented By Dr. Satyabrata Bhanja Aslesha.E M.Pharmacy 1 st yr

2. AIR HANDLING SYSTEMS CONTENTS HVAC systems Air handling units Air filteration systems Dust collectors Humidity and temperature control

3. HVAC systems Heating Ventilation and Air Conditioning systems are the integral part of environmental control system design. Basic components of HVAC: Air Handling Unit Air distribution Dust network Insulator Dampers/valves Return lower & grills. Air filters

4. Air Handling Unit AHU is a device used to condition and circulate air as part of a heating ventilating and air-conditioning ( HVAC ) system . It is a large metal box containing a blower, heating or cooling elements, filter racks or chambers, humidity & temperature control loops .  

5. Air Handling Unit

6. Temperature and humidity control Temperatures in the 68-74 F (19-23 C) range is comfortable for working environment. Temperature control is important in the areas where autoclaves, ovens, dry heat strerilization tunnels are present. Humidity comfort levels are in the 45-55% RH range. Air dryers can be used to maintain lower than normal humidity levels.

7. AIR FILTERATION SYSTEMS CONTENTS Introduction Types of filteration Mechanisms of filteration Types of air filters

8. I ntroduction Filteration is an important aspect of environmental control in Pharmaceutical industry. The main aim of filteration is to produce dust free atmosphere. It is required in areas like spray drying, coating, granulating, milling, packaging etc. Filters are selected based on the required environment.

9. Mechanisms of air filteration Air filteration involves the removal of unwanted particles due to collision of particles with the filter. Such removal of particles due to collisions are governed by forces called as Impingement Diffusion I nterception

10. Mechanisms of air filteration Impingement It is also called as Inertial impaction. Particle inertia causes it to leave the flow streamlines and impact on the fiber. This is called as spraining effect. This is not suitable for particles of size <5 microns.

11. Mechanisms of air filteration Diffusion This is also known as Brownian Movement resulting in the movement of particles from molecular collisions. Efficient method for particles of size <1 microns.

12. Mechanisms of air filteration Interception The particle/droplet collides to the one of the filter’s fibre after coming close enough to it. Oil metal plates/mesh are used. Affects the particles above 4 microns.

13. Air filter efficiency Air filter efficiency is Maximum – impingement in low velocity diffusion at high velocities Minimum – impingement in high velocity diffusion at low velocities

14. Air filters Air filters are made up of fibre glass, sinter glass, charcoal, glass wool, dry fabric, oil wetting fabric. Arrangement : sandwich flat disk pleated box Purpose : final filter post filter fine filter intermediate filter

15. Types of air filters Ultra low penetration and high efficiency particulate air filters (ULPA & HEPA) Packed towers Membrane filter catridges Hydrophobic filters

16. HEPA FILTER HEPA is an acronym for “High Efficiency Particulate Air” This type of air filter can remove at least 99.97% of dust, pollen, mold, bacteria and any airborne particles with a size of 0.3 micrometres ( μm )

17. HEPA FILTER Media   is the filtering material.  Eg : glass fiber , synthetic fiber , non-woven fiber Sealant   is the adhesive material that creates a leak-proof seal between the filter media and the frame. Frame   is where the filter media is inserted. Eg : aluminum , stainless steel, plastic or wood. Faceguard   is a screen attached to the filter to protect the filter media during handling and installation. Gasket  is a rubber or sponge like material used to prevent air leaks between the filter and its housing by compressing the two together.

18. HEPA FILTER Construction : HEPA filter is constructed of borosilicate microfibres in the form of pleated sheet Sheet is pleated to increase the overall filtration surface area. The pleats are separated by serrated aluminum baffles or stitched fabric ribbons, which direct airflow through the filter This combination of pleated sheets and baffles acts as filtration medium.

19. HEPA FILTER It is installed into an outer frame made of fire-rated particle board, aluminum, or stainless steel The frame-media junctions are permanently glued or ‘‘pot-sealed’’ to ensure a leak proof

20. HEPA FILTER HEPA filter performance is dependent upon th following characteristics: Air flow Temperature Pollutant loading Dust holding capacity Filter media Contruction of HEPA Operating conditions etc.

21. Testing of HEPA filters There are 2 separate tests for HEPA and ULPA filter collection efficies . HEPA efficeincy is rated using a thermal di octyl phthalate (DOP) test. The test dust for HEPA filters is mono-sized, DOP particles, generated by vapourization and condensation. Photometer measures particle penetration by sensing the scattered light. ULPA efficiency is tested using a particle counter upstream & downstream of filter. Automizer injects DOP,alcohol & mineral oil in hexane to generate particles.

22. Mono disperse particles Poly disperse particles

23. Types of air filters 2.Packed towers Packed towers are custom designed to provide removal efficiencies in the range of 95% to 99% for acid and toxic gases with a low pressure drop

24. Types of air filters 3. Membrane filter catridges These are compact, easily handled and can be manufactured as fully disposal form. These are available as either pre filter (particulate and liquid aerosal ) or sterilizing filter (bacterial contaminents ).

25. Types of air filters 4. Hydrophobic filters These are generally used as vent filters. They protect the contents of the containers against contamination in the air which enters or leaves them.

26. Dust collectors Dust collectors are used for equipment maintanance . Air pollution is controlled. Main features Low cost & maintainance Most commonly used for all type of medium from coarse to fine except <5 microns particles. Collection efficiency of 10 to 100 microns with multiclones .

27. Dust collectors Types of dust collectors Dry mechanical collectors Wet collectors & scrubbers Fabric collectors ESP

28. Types of dust collectors 1.Electrostatic precipitators(ESP) M echanism : Ionizing the gas Charging the dust particles Transporting the particles to the collecting tube Neutralizing the dust particles Removing the dust from the collecting surface

29. ESP TYPES Cottrell or single stage – combines ionization and collection in a single stage Penny or Two stage – ionization and collection in different stages Advantages: Large gas volumes & high collection efficiency for small particles. Disadvantages: This is a costly method

30. ESP

31. Dust collectors 2.Fabric collectors Collection mechanism: Impaction Interception Diffusion Advantages: can handle varying exhaust gas flow rates & particle loading

32. Fabric collectors The amount of filter area depends on: Release characteristics of dust Porosity of dust cake Conc. Of dust in carrier gas stream Type of fabric & surface Airflow patternn within the collector Temperature & humidity within the gas stream

33. Fabric collectors

34. Dust collectors 3. Wet collectors Collection mechanism: Collect the droplets Contact particles with water or another liquid Advantages: Can handle high temperature & moisture Dust which represent explosion or fire hazards in the dry form can be wetted and collected

35. Wet collectors Types: Spray dryer Packed towers Wet centrifugal collectors Wet dynamic precipitator Venturi type Orifice type

36. Dust collectors 4. Dry centrifugal collectors Collection efficiency is influenced by size, shape, weight of the particles Conc. Of dust & inlet velocity Types Gravity seperators Inertial seperators Cyclone collectors High efficiency centrifugals

37. Cyclone filter

38. Inspecting the air handling plant Verification of design documentation, including description of installation and functions specification of the requirements Operating procedures Maintenance instructions Maintenance records Training logs Environmental records Walking around the plant

39. Conclusion Air handling systems: Play a major role in the quality of pharmaceuticals Must be designed properly, by professionals Must be treated as a critical system

40. References L.Lachman , The theory and practice of industrial pharmacy Bentleys textbook of pharmaceutics Dust collectors – learning guide for dust collectors [Internet] Handbook of heating, ventilation & air-conditioning.