FORM 2
THE PATENT ACT 1970
(39 of 1970)
&
The Patents Rules  2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION: APPARATUS FOR PROVIDING CLEAN AIR

2. APPLICANT:

1. (a) NAME : Vidya Dairy
(b) NATIONALITY: India
(c) ADDRESS : Anand Agricultural University Campus
Anand-388001
Gujarat  India

3. PREAMBLE TO THE DESCRIPTION
PROVISIONAL

The following specification describes the invention. þ COMPLETE

The following specification particularly describes the invention and the manner in which it is to be performed.

Field of the invention
The present invention relates to an air cleaning apparatus with specific arrangement of mirrors and UV lights for the destruction of microorganisms in the air by photochemical process to create a contaminant free atmosphere in hospitals  laboratories and work areas of dairy  food  agricultural and pharmaceutical industries.

Back ground and prior art of the invention
The increasing level of microbes in the atmosphere is one of the pressing problems in the present age of advanced technology  which may lead to spoilage of the products in dairy  food  agricultural and pharmaceutical industries and may be a risk to patient in hospital sectors. The level of microbial load in the atmosphere depends upon several factors such as meteorological conditions of the locality  sun light  altitude above the ground level  day or night period  air currents  temperature and humidity of the air  seasons of the year etc. Microorganisms present in the atmosphere may be free or adhered on dust particles as bacteria  fungi  lichen  protozoa  viruses and algae cells. So  there is a requirement of contaminant free atmosphere in hospitals  laboratories and work areas of dairy  food  agricultural and pharmaceutical industries.
Laminar air flow systems provide relatively clean air for precise and contaminant free work area. The existing laminar air flow systems comprise High Efficiency Particulate Air (HEPA) filters and similar kind of filters for filtering the microbial airborne contamination in the air. But the microorganisms and other invisible contaminant particles in the air having extremely small sizes can not be filtered by HEPA filters  so the existing systems lack in their effects to provide substantive and efficient clean air to the working area.
Such an apparatus for cleaning air is known from GB1389167 according to which the air cleaning apparatus comprises a laminar flow unit consisting of high efficiency filters for the filtration of contaminant particles in the air and lighting equipment consisting of light source and deviating means (i.e. mirror  prism or light conducting cable) for providing illumination in the work area. The light source in the lighting equipment is kept out side the work zone to avoid the convection currents caused by the heat of the light source which affects the laminar flow of air. The deviating means (i.e. mirror  prism or light conducting cable) in the lighting equipment is kept inside the work zone to deviate the light from the outside light source for providing illumination in the work zone.
US4427427 bearing the title of “Vertical Laminar Flow Filter Module” relates to an improved down flow type filter module for providing clean air to the work area. According to the invention the said filter module comprises permeable filter means having one or more HEPA filters through which a vertical laminar air flow occurs  adjustable nozzle means for varying the direction and velocity of the air curtain passes through HEPA filters which substantially eliminates the turbulence in the floor while contacting the floor  separate blower systems to supply air for the laminar air flow and white fluorescent lights for the illumination of work area.
US4749385 discloses a method for providing clean air to a work piece by laminar air flow created through the conduit having central segment surrounded by the peripheral segment. The central segment and peripheral segment are connected through the opening created at the end position of the central segment. The air flow through the conduit is filtered through an HEPA filter supported within the conduit.
The disadvantages of the above said inventions are that they disclose apparatuses for providing clean and contaminant free work areas in which maximum efficient filtration are done by HEPA filters and similar kinds of filters. But  extremely small size microorganisms  bacterial cells and invisible particles can not be retained by such filters. Therefore  the above said inventions have limitations in their effects.

Object of the invention
The main object of this invention is to provide an apparatus for providing clean air to the working area by photochemical process and effective filters.
Further object of the invention is to provide UV lights for the destruction of microorganisms present in the contaminated air by using UV radiation.
Another object of this invention is to provide mirrors for the multi-reflection of UV radiation.
Still another object of this instant invention is to provide HEPA filters which can retain the destroyed microorganisms and other contaminant particles in the air  after exposing the air to UV radiation.

Summary of the Invention
The present invention discloses an apparatus that provides clean  contaminant free and laminar air flow in the desired working area by cleaning contaminated air formed of microbes  dust or dirt particles and suspended particles by photochemical process and effective filters. Said apparatus comprises a metallic duct of inverted “L” shape having an upright leg region open from the lower part and a lateral arm region extends downwardly to form a substantially rectangular shaped chamber open from the basement. The apparatus further comprises a prefilter secured at the opened lower part of the leg region; UV and blower section including blowers  UV lights and mirrors located at the upper part of the inside region of the rectangular shaped chamber; and HEPA section including HEPA filters located at the lower part of the inside region of the rectangular shaped chamber. Further  an air curtain is placed at the entrance of the working area to primarily reduce the entry of microbial load from the outer atmosphere. The whole system or apparatus is functioned with the help of automatic control mechanism  for the purpose of cleaning contaminated air.
Detail description of the drawings
Fig. 1 illustrates a perspective side view of the apparatus.
Fig. 2 illustrates a front view of the apparatus.
Fig. 3 illustrates a top view of the apparatus.
Fig. 4 illustrates the graph plotted against Contamination Factor (P) v/s Treatment Factor (Q) calculated without enclosure.
Fig. 5 illustrates the graph plotted against Contamination Factor (P) v/s Treatment Factor (Q) calculated with and without enclosure.

Detail description of the invention
Before explaining the present invention in detail  it is to be understood that the invention is not limited in its application to the details of the construction and arrangement of parts illustrated in the accompanying drawings. The invention is capable of other embodiments  as depicted in different figures as described above and of being practiced or carried out in a variety of ways. It is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation.
Referred to the drawings  an apparatus (10) for providing clean air in the desired working area comprises a metallic duct (2) of inverted “L” shape having an upright leg region (11) open from the lower part and a lateral arm region (12) extends downwardly to form a substantially rectangular shaped chamber open from the basement. Said apparatus further comprises a prefilter (1) secured at the opened lower part of the leg region (11) for pre filtering dust or dirt particles in the contaminated air; UV and blower section (3) located at the upper part of the inside region of the rectangular shaped chamber; and HEPA section (4) located at the lower part of the inside region of the rectangular shaped chamber. Said prefilter (1) includes number and combination of cotton filter  wool filter and nylon filter. Further  an air curtain is placed at the entrance of the working area to primarily reduce the entry of microbial load from the outer atmosphere.
Said UV and blower section (3) includes blowers (6)  UV lights (5) and mirrors (9). Said blowers (6) are mounted at the bottom surface of the UV and blower section (3) for sucking the air being passed from the prefilter (1) to the UV and blower section (3) through the metallic duct (2); said UV lights (5) installed in the inside walls of the UV  blower section (3) to produce sterilization effect of UV radiation for destructing the microorganisms; and said mirrors (9)arranged in the inside walls of the UV and blower section (3) for attaining the multi reflection of UV radiation from all sides. The HEPA section (4) includes HEPA filters (7) secured at the bottom surface of the HEPA section (4) for filtering the destroyed microorganisms  bacterial cells and other invisible contaminant particles in the air.
During the working of the apparatus  the air containing contaminated particles enters into the working area from the outer atmosphere through the air curtain that primarily reduces the infiltration of the microbial load in the entered air. Such partially treated contaminated air enters into the prefilter (1) which filters the dust or dirt particles and other suspended particles present in the contaminated air; and the filtered air passes through the UV and blower section (3) by means of sucking of the blowers (6) through the metallic duct (2). The microorganisms that have been left in the filtered air are destroyed in the UV and blower section (3) by means of photochemical process. The photochemical process includes destruction of microorganisms by allowing the multiple reflections of UV lights (5) to collide on the entire filtered air through the arrangement of mirrors (9) provided in the UV and blower section (3).
The air treated in the UV and blower section (3) then enters into the HEPA section (4) in which the HEPA filters (7) filter the microorganisms  bacterial cells and other invisible contaminant particles present in the air entered thereby and provide substantially clean  contaminant free and laminar air flow to the desired working area.

Experiment
Experiments were carried out on an air cleaning apparatus with and without mirror effect.

Testing Procedure
For testing of an air cleaning apparatus  “Exposure of Agar plate Method” was used. This method is very simple and gives direct count. Petri dishes containing agar medium were exposed for 15 minutes and replicated thrice for each experiment. The agar media used were Potato Dextrose Agar (PDA) medium and/or Standard Plate Count Agar (SPCA) medium  as the case may be. Exposed petri dishes were incubated for colony counts. The petri dishes having PDA medium were incubated at 22?C for 5 days  while the petri dishes having SPCA medium were incubated at 37?C for 2 days. Petri dishes of 9 cm diameter and 1.4 cm height were exposed.

Velocity of air flow
The velocity of air nearby petri dishes was 0.48 m/s and 0.55 m/s.

Testing of Air Cleaning Apparatus
An enclosure provided for surrounding an air cleaning apparatus in the form of a cabin having UV tube is termed as the enclosure effect.
a. Air cleaning apparatus without the enclosure was tested with and without mirror effect
(i) Testing of air cleaning apparatus without the mirror effect
Initially  the air cleaning apparatus was tested without mirror and without enclosure effect. Therefore  no mirror was provided in the inside walls of the UV and blower section. The air cleaning apparatus was installed without cabin enclosure. All four UV tubes were kept ON for 30 minutes to provide pretreatment to the air associated with the air cleaning apparatus before exposure of petri dishes. The blower was kept ON during the pretreatment for the air circulation.
(ii) Testing of air cleaning apparatus with the mirror effect
After completing the trials on the air cleaning apparatus without mirror effect  mirrors were placed in the inside walls of the UV and blower section to study the mirror effect. The pretreatment of the air associated with the air cleaning apparatus was done as said above.
b. Testing of air cleaning apparatus with mirror effect having the enclosure in the form of a cabin
In this  the air cleaning apparatus was installed in an enclosure of 2.4 m x 2.4 m x 2.4 m volume. The enclosure was provided with one 15 W UV tube on one of its side walls. It was in front of the air cleaning apparatus. For pretreatment of the air cleaning apparatus  all four UV tubes were kept ON for 10 minutes. During this pretreatment period  the blower was also kept ON for air circulation. The enclosure air was sanitized for 60 minutes using a 15 W UV tube.

Result
For quantification of the mirror effect  the air cleaning apparatus was tested (i) without mounting mirrors in the inside walls of the UV and blower section and (ii) with mirrors mounted in the inside walls of the UV and blower section. Calculated values of Contamination Factor (P) and Treatment Factor (Q) for without and with mirror effect were plotted in the graph as in Fig. 4 and 5  respectively.
The experimental result of the air cleaning apparatus with mirror but without enclosure is indicated by line B as shown in Fig. 4. For the same apparatus the result without enclosure and without mirror are covering the region between lines B and C as shown in Fig. 4. This shows that for the identical condition of the treatment time in one case with mirror and in the other case without mirror  the comparative values are indicated by the slopes of lines as 22 x 106 and 300 x 106 respectively. It is further observed that all the experimental results of the above case with mirror are falling on line B or below. The result of above said apparatus with mirror and with enclosure is indicated by line A as shown in Fig. 5 and the comparative value is indicated by the slope of line as 3 x 106. The following observations emerge from Fig. 4 and 5
(1) For the same value of Q  it is possible to reduce P value about 14 times (22 x 106 /300 x 106) in the air cleaning apparatus having mirror effect as compared to the apparatus without mirror effect.
(2) Under enclosed condition also it is possible to reduce P value about 14 times (3 x 106 /40 x 106) in the air cleaning apparatus having mirror effect as compared to the apparatus without mirror effect for the same value of Q.

Conclusion
The air cleaning apparatus having UV tube and mirror in the inside walls of the UV and blower section is capable of providing more effective UV treatment. It is significantly improving the sterilization effect of UV tube. It is observed that provision of mirror surrounding UV tube in the inside walls of the UV and blower section gives an effect of about 15 times equivalent to a single 30 W UV tube.
The air cleaning apparatus without enclosure but with mirror is giving the Contamination Factor P = 22 x 106 for unity value of Treatment Factor Q. Working with the same apparatus without mirror effect has shown the possible contamination level ranging from P=22 x 106 Q to P=300 x 106 Q. The reason for the Contamination Factor values arrested by line having slope of 22 x 106 in case of the air cleaning apparatus with mirror is due to the availability of sterilization effect enhanced by the mirror during operation time.
The air cleaning apparatus having UV tube and mirrors in the inside walls of the UV and blower section  when housed in sanitized enclosure  is showing further reduction in contamination level. This level is denoted by the operating line having the slope of 3 x 106 in the graph of Contamination Factor (P) v/s Treatment Factor (Q) as shown in Fig. 5.

We Claim 
1. An apparatus (10) for providing clean air in a desired working area comprising a metallic duct (2) of inverted “L” shape  a prefilter (1)  UV and blower section (3) and HEPA section (4);
wherein said metallic duct (2) having an upright leg region (11) open from the lower part and a lateral arm region (12) extends downwardly to form a substantially rectangular shaped chamber open from the basement;
wherein said prefilter (1) is secured at the opened lower part of the leg region (11) for filtering dust or dirt particles in the contaminated air;
wherein said UV and blower section (3) is located at the upper part of the inside region of the rectangular shaped chamber;
wherein said HEPA section (4) is located at the lower part of the inside region of the rectangular shaped chamber.

2. The apparatus (10) for providing clean air in a desired working area as claimed in claim 1  wherein the prefilter (1) includes number and combination of cotton filter  wool filter and nylon filter.

3. The apparatus (10) for providing clean air in a desired working area as claimed in claim 1  wherein the UV and blower section (3) includes blowers (6)  UV lights (5) and mirrors (9);
wherein the blowers (6) are mounted at the bottom surface of the UV and blower section (3) for sucking the air being passed from the prefilter (1) to the UV and blower section (3) through the metallic duct (2);
wherein the UV lights (5) are installed in the inside walls of the UV and blower section (3) to provide UV radiation for destructing the microorganisms;
wherein the mirrors (9) are arranged in the inside walls of the UV and blower section (3) for attaining the multi reflection of UV radiation from all sides.

4. The apparatus (10) for providing clean air in a desired working area as claimed in claim 1  wherein the HEPA section (4) includes HEPA filters (7); wherein the HEPA filters (7) are secured at the bottom surface of the HEPA section (4) for filtering the microorganisms  bacterial cells and other invisible contaminant particles in the air.

5. The method of cleaning by an apparatus (10) comprising following steps:
(a) entering the contaminated air to be cleaned from the outer atmosphere to the working area through an air curtain to primarily reduce the entry of microbial load from the outer atmosphere;
(b) passing air through the air curtain into a prefilter (1) for filtering dust or dirt particles and suspended particles;
(c) sucking up the air being filtered through the prefilter (1) to UV and blower section (3) by means of blowers (6);
(d) destroying the microorganisms of the filtered air in the UV and blower section (3) by means of photochemical process;
wherein said photochemical process includes destruction of microorganisms by allowing the multiple reflections of UV lights (5) to impinge on the entire filtered air through the arrangement of mirrors (9) provided in the UV and blower section (3);
(e) filtering the microorganisms  bacterial cells and other invisible contaminant particles being destroyed in the photochemical process by means of HEPA filters (7) secured in HEPA section (4).

Dated this 14th day of April 2012