Indian Patents. 279393:"AN ENCLOSURE FOR SUSTAINING PERSONNEL IN AN ENVIRONMENT HAVING NUCLEAR, BIOLOGICAL AND CHEMICAL CONTAMINANTS"

Title of Invention	"AN ENCLOSURE FOR SUSTAINING PERSONNEL IN AN ENVIRONMENT HAVING NUCLEAR, BIOLOGICAL AND CHEMICAL CONTAMINANTS"
Abstract	An enclosure for sustaining personnel and equipment in an environment having nuclear, biological and chemical contaminants, over an extended period of time.

Full Text	FIELD OF INVENTION: This invention relates to an environmental control unit. BACKGROUND: Ventilation is defined, as the act of supplying fresh air and getting rid of foul air. Where as air conditioning is a system that alters air to the required temperature and or humidity to suit the conditions as required in an enclosed space. Requirements of systems for different applications vary widely, starting from a simple room air conditioning unit, to a more advanced system that takes care of the requiiciiierus of a laboratory or a sterile room condition of a ' surgical theatre. In room air conditioning it is the normal practice to recycle the air within the enclosed space repeatedly after either cooling or heating. This reduces the thermal load of the system as only very small quantity of fresh, unconditioned air is drawn from outside. Some form of simple filtration is also employed to trap dust particles present in the enclosed space. These filters do not remove and or trap pathogens, pollen, smoke, gas or other pollutants present in the enclosed space. In a laboratory or a surgical theatre, along with the requirements of comfort-conditioning, other needs like sterility of the room, possibility of ingress of pollutants from out side have also to be taken into consideration. In these cases some amount of chemical or biological contaminants are generated within the enclosed space and have to be removed to ensure safety of the occupants. In most of these applications ventilation units handle the removal, replenishment and filtration of incoming air. Air which is pumped out of the system is let out into the environment with out any treatment. Recirculation of air within an enclosed space and or air drawn from outside has to be rigorously filtered to ensure contamination free conditions. Also air inside the enclosure must be maintained at a pressure higher than the outside to prevent ingress of air borne pollutants from the outside. ! A separate air conditioning system, with sufficiently high thermal rating is used to condition the air inside the enclosure. The disadvantage is that if sterile condition is to be maintained then high amount of air change per hour (ACH) is required which in turn will increase the thermal load on the conditioning system. HVAC systems (Heating, ventilating and air conditioning) combine the ventilation and conditioning requirements and provide adequate comfort levels to the occupants along with basic protection against airborne pollutants. The HVAC units do not exhaust the air available within the enclosure fully but combine the fresh air intake with recirculation air and use filters like 1. Fiber glass filters to remove sand and dust particles greater than 10 micron size. HEP A (High efficiency particulate air) filters to remove airborne dispersions of ultra fine solid and liquid particulates such as dust and pollen, radioactive particle contaminants, and aerosols. HEPA filters trap aerosols of size greater than 0.3 microns and particulate matter of size greater than 0.15 microns. However, conventional commercially-available HEPA filters can not intercept gaseous chemical compound or a gaseous particle of extremely small size. Also high airflow resistance, due to dust loads, prevents the use of conventional HEPA filters in critical applications due to limitation of available space. None of the above and other known air handling system, has the ability to function in a effective manner for a sustained period of protection in case of a Nuclear, Biological or Chemical (NBC) attack launched during a war or a terrorist attack, as conventional air handling units are not designed to handle large increase in air flow resistance that are likely to occur due to large amounts of contaminants released intentionally in a war zone. To provide effective coverage, these units will have to necessarily be scaled up in size and would occupy considerable amount space. PRIOR ART: Several attempts have been made in this field for providing environmental protection for the occupants in an enclosed space. US Patent 4409889 discloses a modular clean room for maintaining an environment free of particulate contaminants with prefabricated modules, including an air recirculation and filtration module. US Patent 4526013 discloses a system suitable for crew compartment protection system independent of the vehicles main engine and electrical system, capable of producing three phase alternating current to operate the pressurization, ventilation, and filtration systems. US Patent 4667580 discloses clean room module for maintaining the cleanliness, temperature, humidity, and pressurization required for the work space within the room. The module is also provided with self contained air conditioning unit which has two independent air systems whereby only a portion of the re-circulating air need be conditioned. US Patent 4629482 discloses a portable room purifier incorporating HEPA filter elements with high air flow rates. US Patent 5251457 discloses a pressurized air distribution system providing intermittent cooling for personnel wearing protective garments and working in hot contaminated environment. US Patent 6289974 discloses an integrated heat recovery ventilator using pleated HEP A filters with regenerative heat recovery capability. US Patent 6711470 discloses a system, method and apparatus for monitoring and adjusting quality of indoor air using an array of sensors to sample and obtain signatures representative of contaminants present in the air. Corrective actions taken are intended to prevent personnel from being overexposed to hazardous contaminants and minimize the cost of operating HVAC system. US Patent 6857956 discloses an air lock system and method for protecting a toxic-free area from penetration of contaminants from a NBC attack. US Patent 6919809 discloses a method of optimization of building f ventilation by system and zone level action and selecting suitable ventilation control strategy on determination of presence of carbon dioxide in air sample. US Patent 6840986 discloses an air purifying filter for building air supply and respirators useful against NBC (nuclear, biological and chemical) attacks. This invention envisages use of a series of pleated composite layer filter, impregnated with carbon particles that can withstand NBC attacks. US Patent 6997976 discloses a low resistance gas absorption filter media suitable for gas filtration with substantially improved flow rate to pressure drop ratio and capable of protection against agents used in chemical warfare. None of the above air handling system, has the ability to function in a effective manner for a sustained period of protection in case of a Nuclear, Biological or Chemical (NBC) attack launched during a war or a terrorist attack. To overcome the limitations of the known prior arts this invention envisages a unitary packaged thermally conditioned air handling system to protect occupants and equipment in an enclosed space against airborne nuclear, biological and chemical agents. OBJECTS OF THE INVENTION: One object of this invention is to provide an air handling system that .is a compact and composite unit, consisting of an air conditioning unit with built in ventilation system capable of providing required quantity of conditioned and filtered toxic free air inside a shelter to protect occupants and equipment against airborne nuclear, biological and chemical agents. Another object of the invention is to provide a unitary packaged thermally conditioned air handling system to protect occupants and equipment in an enclosed space against airborne nuclear, biological and chemical agents, capable of efficient and trouble free operation in extreme environmental temperature condition of- 30 to + 55 degrees centigrade and provide 96 Hrs protection for 6 to 10 occupants. Another object of the invention is to provide a unitary packaged thermally conditioned air handling system that occupies lesser floor space, and has lower weight to capacity ratio and lower power consumption to capacity ratio. Another object of the invention is to provide a unitary packaged thermally conditioned air handling system that has the lower capital and maintenance cost to capacity ratio. DESCRIPTION OF THE INVENTION; According to this invention there is provided an enclosure for sustaining personnel and equipment in an environment having nuclear, biological and chemical contaminants, over an extended period of time, said enclosure comprising an air tight compartment for housing personnel and equipment; air handling means for handling air inside the compartment; an ingress opening for leading the air from said compartment to said air handling means; egress opening for leading handled air from the air handling means to the compartment; said air handling means comprising a filteration unit having for filtering air; said nuclear, biological and chemical contaminants; a thermal conditioning unit for receiving air either from the compartment or filtering unit and maintaining the temperature of the air between 20 to 30 degree Celsius; said thermal conditioning unit having a filter element and means to transmit filtered and temperature conditioned air to said compartment via the egress opening; a suction means for controllably drawing ambient air through the air handling means; exhaust means for controllably exhausting a portion of the air from the compartment; and a controlling means for selectively controlling the movement of air through the filtering unit or the temperature conditioning unit. The environmental control unit of the invention is a unitary packaged unit capable of providing air conditioning, heating and NBC filtering needs for an enclosure. It consists of an enclosure for sustaining personnel and equipment in an environment having nuclear, biological and chemical contaminants, over an extended period of time. The enclosure comprising an air tight compartment for housing personnel and equipment; an air handling means for handling air inside the compartment; an ingress opening for leading the air from said compartment to said air handling means; egress opening for leading handled air from the air handling means to the compartment. The air handling unit consists of a filtration unit having a series of filter elements for filtering air, including a carbon filter for filtering out nuclear, biological and chemical contaminants. A thermal conditioning unit for receiving air either from the compartment or filtering unit and maintaining the temperature of the air between 20 and 30 degree Celsius; said thermal conditioning unit having a filter element and means to transmit filtered and temperature conditioned air to the said compartment via the egress opening; a suction means for controllably drawing ambient air through the air handling means; exhaust means for controllably exhausting a portion of the air from the compartment ; a controlling means for selectively controlling the movement of air through the filtering unit or the temperature conditioning unit. The filter unit includes following elements: a coarse filter element for filtering particulates of size greater than 40 microns ; a fine filter element for filtering particulates of size greater than 10 microns ; a HEPA filter element for filtering particulates of size greater than 0,3 microns ; and a r carbon filter element adapted to filter nuclear, biological and chemical contaminants by adsorption The thermal conditioning unit includes a heating element and a cooling element. The environment control unit has a selector valve for diverting a stream of ambient air selectively through the filter unit. The enclosure includes an array of sensors for sensing chemical and biological contaminants qualitatively and quantitatively, in the external and internal environment of the enclosure. The signal received form the array of sensors is used to control the selector valve to suitably process the air through the filtration unit. Chemical sensors are particularly set for identification of chemical, biological contaminants and on detection of any harmful substance will switch on one or more of the modular filtration units. The enclosure includes auxiliary oxygen storage cylinders or tanks, carbon dioxide absorbers, and oxygen generators along with gas analysers for verification of qualitative and quantitative presence of oxygen and carbon dioxide in the recirculation system. Signal received from the gas analysers is utilized to selectively to maintain preset value of oxygen and carbon dioxide within. the enclosure. The enclosure includes air lock chamber with controlled air flow and over pressure valve and quarantine enclosure to prevent ingress of contaminants in to the enclosure. Gas analysers installed in the system detect and control the levels of oxygen and carbon dioxide by selectively operating oxygen generators, carbon dioxide absorbers, external air scrubber and or oxygen storage tanks to maintain preset levels. The structures of the enclosure are so designed to with stand man made or natural quakes up to 7.5 on Richter scale by suitable tie beams, floating and damped footing, to protect the functionality of the installed instruments and system. Walls of the enclosure are lined or coated with such materials to prevent electromagnetic interference and to sustain the working of sensitive equipment installed inside the enclosure. Remote external radiation shield with sensors are also deployed to protect the enclosure from electro magnetic interference (EMI) and counter act the effect of radiation. An activated carbon filter functions by removing molecules from an air stream by adsorption in which molecules are trapped in pores of the carbon granules. Activated carbon is an effective absorbent for removal of a wide range of chemical vapors due to its extensive micro-porosity and broad range of pore sizes. In order to filter high vapor pressure chemicals, certain reactants are added to the activated carbon. The reactants react with the gas passing through the filter to form products that are captured by the filter or rendered innocuous. Due to the usage of high performance NBC filtering components, ;t is possible to integrate HVAC components into the same unitary packaged unit to meet the air handling requirements without undue increase in weight or bulk. Modular construction and integration of filtration and conditioning units has resulted in (a) 50% space saving; (b) 40% mass saving; and (c) 40% energy saving as compared to conventional HVAC ( Heating, Ventilating, Air Conditioning) units. Modular design of filtration unit with selectable configuration of flow rate has resulted in saving in installation and inventory costs. Modular design of filtration unit with uniform dimension allows easier and faster configuration of the unit to provide protection against a known specific threat and or increased duration of protection. Independent modular design of filter elements permit quicker replacement of damaged module as against composite filters wherein the entire component will have to be replaced due to failure of a part. The environment control unit of the present invention includes heaters and coolers for thermally conditioning the air stream, after the NBC filtering, as well as blower for circulating, air stream back to the enclosed space under positive air pressure. The unit can either be used in a normal mode, when there is no threat of NBC attack. In this mode a honey comb filter, for return air, is online along with thermal conditioning system and all other filters are kept off the line by operating a directional control valve. In NBC mode all the filtering media like coarse filter, fine filter, HEPA filter and carbon filters are included in the system to provide comfortable breathable atmosphere against external and/or internal release of nuclear, biological, and chemical contaminants. BRIEF DESCRIPTION OF DRAWING: The invention will now be described with respect to the accompanying drawings in which Figure 1 is a schematic diagram of an air handling system with an environment control unit according to an embodiment of the present invention used to protect occupants and equipment in an enclosed space against airborne nuclear, biological and chemical agents, Detailed description of the embodiment: Figure 1 is a representative non limiting embodiment of the present invention, wherein the environment control unit is a single packaged unit that incorporates HVAC equipment and nuclear, biological and chemical filtering means into a single integrated assembly. Enclosure, 200 is connected to Environment control unit, 220 by air inlet 240 and air outlet 230 connections. Air outlet connection is connected to the controller valve 260, which selectively connects the air outlet to normal mode filtration 260 (a),or NBC mode filtration, 260(b). Thermal conditioning unit 280 which is an integral part of environment control unit, 220 consist of heaters and coolers to condition the air .and lets in the air through air inlet, 240 in to the enclosure, 200. Ambient air controller, 245 selectively admits air to the system through environment control unit. Enclosure 200, is connected to air lock chambers 205 and 206. Quarantine enclosure 210 is connected to the enclosure through air lock 206. External chemical sensor 235, internal chemical sensor 236, gas analysers 237,238 for oxygen and carbon dioxide are connected to control unit 241, to selectively process the air stream through the filtration unit. While considerable emphasis has been placed herein on the particular features of an environment control unit, the improvisation with regards to it, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiment without departing from the principles of the invention. These and other modifications in the nature of the invention or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. We Claim; 1. An enclosure for sustaining personnel and equipment in an environment having nuclear, biological and- chemical contaminants, over an extended period of time, said enclosure comprising: a) an air tight compartment for housing personnel and equipment; b) air handling means for handling air inside the compartment; c) an ingress opening for leading the air from said compartment to said air handling means; d) egress opening for leading handled air from the air handling means to the compartment. said air handling means comprising: a) a filteration unit having for filtering air; said nuclear, biological and chemical contaminants; b) a thermal conditioning unit for receiving air either from the compartment or filtering unit and maintaining the temperature of the air between 20 to 30 degree Celsius; c) said thermal conditioning unit having a filter element and means to transmit filtered and temperature conditioned air to said compartment via the egress opening; d) a suction means for controllably drawing ambient air through the air handling means; e) exhaust means for controllably exhausting a portion of the air from the compartment; and f) a controlling means for selectively controlling the movement of air through the filtering unit or the temperature conditioning unit. 2. An enclosure as claimed in claim 1, wherein the filter unit includes the following elements: a) a coarse filter element for filtering particulates of size greater than 40 microns; b) a fine filter element for filtering particulates of size greater than 10 microns; c) a HEPA filter element for filtering particulates of size greater than 0.3 microns; and d) a carbon filter element adapted to filter nuclear, biological and chemical contaminants by adsorption. 3. An enclosure as claimed in claim 1, wherein the thermal conditioning unit includes a heating element. 4. An enclosure as claimed in claim 1, wherein thermal conditioning unit includes a cooling element. 5. An enclosure as claimed in claim 1, wherein the environment control unit has a selector value for diverting a stream of ambient air selectively through the filter unit. 6. An enclosure as claimed in claim 1, wherein the enclosure includes at least one sensor for sensing one or more chemicals qualitatively and qualitatively, present in the environment external to the enclosure; said sensor co-operating with the filtration unit. 7. An enclosure as claimed in claim 1, wherein the enclosure includes at least one sensor for sensing one or more gases qualitatively and qualitatively, present in the internal environment of the enclosure; said sensor co-operating with the filtration unit. 8. An enclosure as claimed in claim 1, wherein the enclosure includes at least one auxiliary oxygen storage cylinder in communication with air inlet means. 9. An enclosure as claimed in claim 1, wherein the enclosure includes a carbon dioxide absorber in communication with recirculation air controller. 10. An enclosure as claimed in claim 1, wherein the enclosure includes an oxygen generator in communication with air inlet means. 11. An enclosure as claimed in claim 1, in which a gas analyzer is fitted for analyzing qualitatively and qualitatively the amount of oxygen, carbon dioxide present in the enclosure; said analyzer co operating with the ventilation control unit. 12. An enclosure as claimed in claim 1, in which an air scrubbing means is fitted to clean the in take air. 13. An enclosure as claimed in claim 1, to which a1 quarantine enclosure is attached for accepting, permitting personnel and equipment to be introduced to the enclosure at an intermediate stage and clearing their hazards level. 14. An enclosure as claimed in claim 1, to which at least one air lock chamber is fitted, permitting ingress and egress of personnel and equipment. 15. An enclosure as claimed in claim 1, wherein the enclosure includes automatic ventilation shut off means; said automatic ventilation shut off means cooperating with the sensors. 16. An enclosure as claimed in claim 1, to which an automatic ingress, egress locking means is fitted; said automatic ingress, egress locking means cooperating with the sensors; said automatic locking means includes a manual over-hide.

Full Text

FIELD OF INVENTION:
This invention relates to an environmental control unit. BACKGROUND:
Ventilation is defined, as the act of supplying fresh air and getting rid of foul air. Where as air conditioning is a system that alters air to the required temperature and or humidity to suit the conditions as required in an enclosed space.
Requirements of systems for different applications vary widely, starting from a simple room air conditioning unit, to a more advanced system that takes care of the requiiciiierus of a laboratory or a sterile room condition of a ' surgical theatre.
In room air conditioning it is the normal practice to recycle the air within the enclosed space repeatedly after either cooling or heating. This reduces the thermal load of the system as only very small quantity of fresh, unconditioned air is drawn from outside. Some form of simple filtration is also employed to trap dust particles present in the enclosed space. These filters do not remove and or trap pathogens, pollen, smoke, gas or other pollutants present in the enclosed space.
In a laboratory or a surgical theatre, along with the requirements of comfort-conditioning, other needs like sterility of the room, possibility of ingress of
pollutants from out side have also to be taken into consideration. In these cases some amount of chemical or biological contaminants are generated within the enclosed space and have to be removed to ensure safety of the occupants.
In most of these applications ventilation units handle the removal, replenishment and filtration of incoming air. Air which is pumped out of the system is let out into the environment with out any treatment.
Recirculation of air within an enclosed space and or air drawn from outside has to be rigorously filtered to ensure contamination free conditions. Also air inside the enclosure must be maintained at a pressure higher than the outside to prevent ingress of air borne pollutants from the outside.
!
A separate air conditioning system, with sufficiently high thermal rating is used to condition the air inside the enclosure. The disadvantage is that if sterile condition is to be maintained then high amount of air change per hour (ACH) is required which in turn will increase the thermal load on the conditioning system.
HVAC systems (Heating, ventilating and air conditioning) combine the ventilation and conditioning requirements and provide adequate comfort levels to the occupants along with basic protection against airborne pollutants.
The HVAC units do not exhaust the air available within the enclosure fully but combine the fresh air intake with recirculation air and use filters like
1. Fiber glass filters to remove sand and dust particles greater than 10
micron size.
HEP A (High efficiency particulate air) filters to remove airborne
dispersions of ultra fine solid and liquid particulates such as dust and pollen,
radioactive particle contaminants, and aerosols. HEPA filters trap aerosols of
size greater than 0.3 microns and particulate matter of size greater than 0.15
microns.
However, conventional commercially-available HEPA filters can not intercept gaseous chemical compound or a gaseous particle of extremely small size. Also high airflow resistance, due to dust loads, prevents the use of conventional HEPA filters in critical applications due to limitation of available space.
None of the above and other known air handling system, has the ability to function in a effective manner for a sustained period of protection in case of a Nuclear, Biological or Chemical (NBC) attack launched during a war or a terrorist attack, as conventional air handling units are not designed to handle large increase in air flow resistance that are likely to occur due to large amounts of contaminants released intentionally in a war zone. To provide effective coverage, these units will have to necessarily be scaled up in size and would occupy considerable amount space.
PRIOR ART:
Several attempts have been made in this field for providing environmental protection for the occupants in an enclosed space.
US Patent 4409889 discloses a modular clean room for maintaining an environment free of particulate contaminants with prefabricated modules, including an air recirculation and filtration module.
US Patent 4526013 discloses a system suitable for crew compartment protection system independent of the vehicles main engine and electrical system, capable of producing three phase alternating current to operate the pressurization, ventilation, and filtration systems.
US Patent 4667580 discloses clean room module for maintaining the cleanliness, temperature, humidity, and pressurization required for the work space within the room. The module is also provided with self contained air conditioning unit which has two independent air systems whereby only a portion of the re-circulating air need be conditioned.
US Patent 4629482 discloses a portable room purifier incorporating HEPA filter elements with high air flow rates.
US Patent 5251457 discloses a pressurized air distribution system providing intermittent cooling for personnel wearing protective garments and working in hot contaminated environment.
US Patent 6289974 discloses an integrated heat recovery ventilator using pleated HEP A filters with regenerative heat recovery capability.
US Patent 6711470 discloses a system, method and apparatus for monitoring and adjusting quality of indoor air using an array of sensors to sample and obtain signatures representative of contaminants present in the air. Corrective actions taken are intended to prevent personnel from being overexposed to hazardous contaminants and minimize the cost of operating HVAC system.
US Patent 6857956 discloses an air lock system and method for protecting a toxic-free area from penetration of contaminants from a NBC attack.
US Patent 6919809 discloses a method of optimization of building
f
ventilation by system and zone level action and selecting suitable ventilation control strategy on determination of presence of carbon dioxide in air sample.
US Patent 6840986 discloses an air purifying filter for building air supply and respirators useful against NBC (nuclear, biological and chemical) attacks. This invention envisages use of a series of pleated composite layer filter, impregnated with carbon particles that can withstand NBC attacks.
US Patent 6997976 discloses a low resistance gas absorption filter media suitable for gas filtration with substantially improved flow rate to pressure drop ratio and capable of protection against agents used in chemical warfare.
None of the above air handling system, has the ability to function in a effective manner for a sustained period of protection in case of a Nuclear, Biological or Chemical (NBC) attack launched during a war or a terrorist attack.
To overcome the limitations of the known prior arts this invention envisages a unitary packaged thermally conditioned air handling system to protect occupants and equipment in an enclosed space against airborne nuclear, biological and chemical agents.
OBJECTS OF THE INVENTION:
One object of this invention is to provide an air handling system that .is a compact and composite unit, consisting of an air conditioning unit with built in ventilation system capable of providing required quantity of conditioned and filtered toxic free air inside a shelter to protect occupants and equipment against airborne nuclear, biological and chemical agents.
Another object of the invention is to provide a unitary packaged thermally conditioned air handling system to protect occupants and equipment in an enclosed space against airborne nuclear, biological and chemical agents, capable of efficient and trouble free operation in extreme environmental temperature condition of- 30 to + 55 degrees centigrade and provide 96 Hrs protection for 6 to 10 occupants.
Another object of the invention is to provide a unitary packaged thermally conditioned air handling system that occupies lesser floor space, and has lower weight to capacity ratio and lower power consumption to capacity ratio.
Another object of the invention is to provide a unitary packaged thermally conditioned air handling system that has the lower capital and maintenance cost to capacity ratio.
DESCRIPTION OF THE INVENTION;
According to this invention there is provided an enclosure for sustaining personnel and equipment in an environment having nuclear, biological and chemical contaminants, over an extended period of time, said enclosure comprising an air tight compartment for housing personnel and equipment; air handling means for handling air inside the compartment; an ingress opening for leading the air from said compartment to said air handling means; egress opening for leading handled air from the air handling means to the compartment; said air handling means comprising a filteration unit having for filtering air; said nuclear, biological and chemical contaminants; a thermal conditioning unit for receiving air either from the compartment or filtering unit and maintaining the temperature of the air between 20 to 30 degree Celsius; said thermal conditioning unit having a filter element and means to transmit filtered and temperature conditioned air to said compartment via the egress opening; a suction means for controllably drawing ambient air through the air handling means; exhaust means for controllably
exhausting a portion of the air from the compartment; and a controlling means for selectively controlling the movement of air through the filtering unit or the temperature conditioning unit.
The environmental control unit of the invention is a unitary packaged unit capable of providing air conditioning, heating and NBC filtering needs for an enclosure.
It consists of an enclosure for sustaining personnel and equipment in an environment having nuclear, biological and chemical contaminants, over an extended period of time.
The enclosure comprising an air tight compartment for housing personnel and equipment; an air handling means for handling air inside the compartment; an ingress opening for leading the air from said compartment to said air handling means; egress opening for leading handled air from the air handling means to the compartment.
The air handling unit consists of a filtration unit having a series of filter elements for filtering air, including a carbon filter for filtering out nuclear, biological and chemical contaminants.
A thermal conditioning unit for receiving air either from the compartment or filtering unit and maintaining the temperature of the air between 20 and 30 degree Celsius; said thermal conditioning unit having a filter element and means to transmit filtered and temperature conditioned air to the said compartment via the egress opening; a suction means for controllably drawing ambient air through the air handling means; exhaust means for controllably exhausting a portion of the air from the compartment ; a controlling means for selectively controlling the movement of air through the filtering unit or the temperature conditioning unit.
The filter unit includes following elements: a coarse filter element for filtering particulates of size greater than 40 microns ; a fine filter element for filtering particulates of size greater than 10 microns ; a HEPA filter
element for filtering particulates of size greater than 0,3 microns ; and a
r
carbon filter element adapted to filter nuclear, biological and chemical contaminants by adsorption
The thermal conditioning unit includes a heating element and a cooling
element.
The environment control unit has a selector valve for diverting a stream of
ambient air selectively through the filter unit.
The enclosure includes an array of sensors for sensing chemical and biological contaminants qualitatively and quantitatively, in the external and internal environment of the enclosure. The signal received form the array of sensors is used to control the selector valve to suitably process the air through the filtration unit. Chemical sensors are particularly set for
identification of chemical, biological contaminants and on detection of any harmful substance will switch on one or more of the modular filtration units.
The enclosure includes auxiliary oxygen storage cylinders or tanks, carbon
dioxide absorbers, and oxygen generators along with gas analysers for
verification of qualitative and quantitative presence of oxygen and carbon
dioxide
in the recirculation system. Signal received from the gas analysers is utilized
to selectively to maintain preset value of oxygen and carbon dioxide within.
the enclosure.
The enclosure includes air lock chamber with controlled air flow and over pressure valve and quarantine enclosure to prevent ingress of contaminants in to the enclosure.
Gas analysers installed in the system detect and control the levels of oxygen and carbon dioxide by selectively operating oxygen generators, carbon dioxide absorbers, external air scrubber and or oxygen storage tanks to maintain preset levels.
The structures of the enclosure are so designed to with stand man made or natural quakes up to 7.5 on Richter scale by suitable tie beams, floating and damped footing, to protect the functionality of the installed instruments and system. Walls of the enclosure are lined or coated with such materials to prevent electromagnetic interference and to sustain the working of sensitive equipment installed inside the enclosure.
Remote external radiation shield with sensors are also deployed to protect the enclosure from electro magnetic interference (EMI) and counter act the effect of radiation.
An activated carbon filter functions by removing molecules from an air stream by adsorption in which molecules are trapped in pores of the carbon granules. Activated carbon is an effective absorbent for removal of a wide range of chemical vapors due to its extensive micro-porosity and broad range of pore sizes. In order to filter high vapor pressure chemicals, certain reactants are added to the activated carbon. The reactants react with the gas passing through the filter to form products that are captured by the filter or rendered innocuous.
Due to the usage of high performance NBC filtering components, ;t is possible to integrate HVAC components into the same unitary packaged unit to meet the air handling requirements without undue increase in weight or bulk.
Modular construction and integration of filtration and conditioning units has resulted in
(a) 50% space saving;
(b) 40% mass saving; and
(c) 40% energy saving
as compared to conventional HVAC ( Heating, Ventilating, Air Conditioning) units.
Modular design of filtration unit with selectable configuration of flow rate has resulted in saving in installation and inventory costs.
Modular design of filtration unit with uniform dimension allows easier and faster configuration of the unit to provide protection against a known specific threat and or increased duration of protection. Independent modular design of filter elements permit quicker replacement of damaged module as against composite filters wherein the entire component will have to be replaced due to failure of a part.
The environment control unit of the present invention includes heaters and coolers for thermally conditioning the air stream, after the NBC filtering, as well as blower for circulating, air stream back to the enclosed space under positive air pressure.
The unit can either be used in a normal mode, when there is no threat of NBC attack. In this mode a honey comb filter, for return air, is online along with thermal conditioning system and all other filters are kept off the line by operating a directional control valve. In NBC mode all the filtering media like coarse filter, fine filter, HEPA filter and carbon filters are included in the system to provide comfortable breathable atmosphere against external and/or internal release of nuclear, biological, and chemical contaminants.
BRIEF DESCRIPTION OF DRAWING:
The invention will now be described with respect to the accompanying drawings in which
Figure 1 is a schematic diagram of an air handling system with an environment control unit according to an embodiment of the present
invention used to protect occupants and equipment in an enclosed space against airborne nuclear, biological and chemical agents,
Detailed description of the embodiment:
Figure 1 is a representative non limiting embodiment of the present invention, wherein the environment control unit is a single packaged unit that incorporates HVAC equipment and nuclear, biological and chemical filtering means into a single integrated assembly.
Enclosure, 200 is connected to Environment control unit, 220 by air inlet 240 and air outlet 230 connections. Air outlet connection is connected to the controller valve 260, which selectively connects the air outlet to normal mode filtration
260 (a),or NBC mode filtration, 260(b). Thermal conditioning unit 280 which is an integral part of environment control unit, 220 consist of heaters and coolers to condition the air .and lets in the air through air inlet, 240 in to the enclosure, 200. Ambient air controller, 245 selectively admits air to the system through environment control unit. Enclosure 200, is connected to air lock chambers 205 and 206. Quarantine enclosure 210 is connected to the enclosure through air lock 206. External chemical sensor 235, internal chemical sensor 236, gas analysers 237,238 for oxygen and carbon dioxide are connected to control unit 241, to selectively process the air stream through the filtration unit.
While considerable emphasis has been placed herein on the particular features of an environment control unit, the improvisation with regards to it,

it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiment without departing from the principles of the invention. These and other modifications in the nature of the invention or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We Claim;
1. An enclosure for sustaining personnel and equipment in an environment having nuclear, biological and- chemical contaminants, over an extended period of time, said enclosure comprising:
a) an air tight compartment for housing personnel and
equipment;
b) air handling means for handling air inside the compartment;
c) an ingress opening for leading the air from said
compartment to said air handling means;
d) egress opening for leading handled air from the air handling
means to the compartment.
said air handling means comprising:
a) a filteration unit having for filtering air; said nuclear, biological
and chemical contaminants;
b) a thermal conditioning unit for receiving air either from the
compartment or filtering unit and maintaining the temperature of
the air between 20 to 30 degree Celsius;
c) said thermal conditioning unit having a filter element and means
to transmit filtered and temperature conditioned air to said
compartment via the egress opening;
d) a suction means for controllably drawing ambient air through the
air handling means;
e) exhaust means for controllably exhausting a portion of the air
from the compartment; and
f) a controlling means for selectively controlling the movement of air
through the filtering unit or the temperature conditioning unit.
2. An enclosure as claimed in claim 1, wherein the filter unit
includes the following elements:
a) a coarse filter element for filtering particulates of size greater
than 40 microns;
b) a fine filter element for filtering particulates of size greater
than 10 microns;
c) a HEPA filter element for filtering particulates of size greater
than 0.3 microns; and
d) a carbon filter element adapted to filter nuclear, biological
and chemical contaminants by adsorption.
3. An enclosure as claimed in claim 1, wherein the thermal
conditioning unit includes a heating element.
4. An enclosure as claimed in claim 1, wherein thermal conditioning
unit includes a cooling element.
5. An enclosure as claimed in claim 1, wherein the environment
control unit has a selector value for diverting a stream of ambient
air selectively through the filter unit.
6. An enclosure as claimed in claim 1, wherein the enclosure
includes at least one sensor for sensing one or more chemicals
qualitatively and qualitatively, present in the environment
external to the enclosure; said sensor co-operating with the
filtration unit.
7. An enclosure as claimed in claim 1, wherein the enclosure
includes at least one sensor for sensing one or more gases
qualitatively and qualitatively, present in the internal environment
of the enclosure; said sensor co-operating with the filtration unit.
8. An enclosure as claimed in claim 1, wherein the enclosure
includes at least one auxiliary oxygen storage cylinder in
communication with air inlet means.
9. An enclosure as claimed in claim 1, wherein the enclosure
includes a carbon dioxide absorber in communication with
recirculation air controller.
10. An enclosure as claimed in claim 1, wherein the enclosure
includes an oxygen generator in communication with air inlet
means.
11. An enclosure as claimed in claim 1, in which a gas analyzer is
fitted for analyzing qualitatively and qualitatively the amount of
oxygen, carbon dioxide present in the enclosure; said analyzer co
operating with the ventilation control unit.
12. An enclosure as claimed in claim 1, in which an air scrubbing
means is fitted to clean the in take air.
13. An enclosure as claimed in claim 1, to which a1 quarantine
enclosure is attached for accepting, permitting personnel and
equipment to be introduced to the enclosure at an intermediate
stage and clearing their hazards level.
14. An enclosure as claimed in claim 1, to which at least one air lock
chamber is fitted, permitting ingress and egress of personnel and
equipment.
15. An enclosure as claimed in claim 1, wherein the enclosure
includes automatic ventilation shut off means; said automatic
ventilation shut off means cooperating with the sensors.
16. An enclosure as claimed in claim 1, to which an automatic
ingress, egress locking means is fitted; said automatic ingress,
egress locking means cooperating with the sensors; said
automatic locking means includes a manual over-hide.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=EjJl85vBrvgeSkmY1zsJ2g==&loc=+mN2fYxnTC4l0fUd8W4CAA==

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Patent Number

279393

Indian Patent Application Number

1736/DEL/2007

PG Journal Number

03/2017

Publication Date

20-Jan-2017

Grant Date

19-Jan-2017

Date of Filing

14-Aug-2007

Name of Patentee

THE DIRECTOR GENERAL, DEFENCE RESEARCH & DEVELOPMENT ORGANIZATION

Applicant Address

DEFENCE RESEARCH & DEVELOPMENT ORGANIZATION, MINISTRY OF DEFENCE, GOVT.OF INDIA, DRDO BHAWAN, RAJAJI MARG, NEW DELHI-110011.

Inventors:

#	Inventor's Name	Inventor's Address
1	RAVINDRA KUMAR CHOUHAN	MINISTRY OF DEFENCE,DEFENCE RESEARCH & DEVELOPMENT ORGANIZATION, RESEARCH & DEV.ESTT. (ENGRS), DIGHI, PUNE-411 015.

PCT International Classification Number

F25D21/14

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA