after reading this description it will become apparent to one skilled in the art how to implement the invention in various alternative embodiments and alternative applications . however , all the various embodiments of the present invention will not be described herein . it is understood that the embodiments presented here are presented by way of an example only , and not limitation . as such , this detailed description of various alternative embodiments should not be construed to limit the scope or breadth of the present invention as set forth below . embodiments herein describe a helmet cooling device which may be attached with or molded into a helmet to provide significant cooling of air inside the helmet through the manipulation of the volume , speed and density of the air passing through the device . in order to obtain a maximum change in temperature of air being drawn into to a helmet cooling system , it is necessary to control not only the volume of air but also the speed and density of the air going to the helmet . to achieve a substantial cooling of the air brought into a cooling system of the helmet , the volume of air moving across a cooling system evaporator should be maximized , and the rate , or velocity , of air moving across the cooling fins of the evaporator should be minimized . in one embodiment of the invention illustrated in fig1 - 5 , a cooling apparatus 100 is provided with an air duct system which controls the flow of air both before and after the evaporator . air is drawn into an inlet air duct 4 through an air intake opening 2 via suction from a blower 20 positioned within the cooling apparatus 100 . the air is first cooled by direct contact of an external surface of an evaporator 16 with a wall ( not shown ) of the intake air duct 4 as initial airflow passes along this wall . in one embodiment , the air temperature at this level is reduced by approximately five ( 5 ) degrees fahrenheit ( f ) from the incoming ambient air temperature . the slightly cooled air then passes through a first opening 6 into a helmet air duct 7 . in one embodiment , the helmet air duct is configured with a wall disposed from the external surface of the evaporator in order to slightly cool the air . in one embodiment , the air then flows into a carbon dioxide ( co 2 ) filter housing 8 and is drawn through a co 2 filter ( not shown ) and into a first chamber 10 . the co 2 filter is not a required component of the cooling system , but if included , it has only minimal effect on the velocity of the air flow . other types of filtration devices may also be used . at the first chamber 10 , the velocity of the air is reduced and the air pressure increases as the air approaches a narrow opening 12 ( also known as the expansion port ) connecting the first chamber with a second chamber 14 at a distal end 11 of the first chamber . the opening 12 has a diameter which is substantially smaller than the diameter of the first chamber 10 in order to sufficiently slow the air flow and increase the pressure in the first chamber 10 . the air then travels through this narrow , reduced - sized opening 12 ( i . e . a valve ) and into the large second chamber 14 , also known as the expansion chamber , which houses the evaporator 16 . the second chamber 14 has a diameter which is substantially larger than the diameter of the opening 12 and an overall volume which is also substantially larger than that of the first chamber 10 . as the high pressure air enters the large second chamber 14 through the narrow opening 12 , it rapidly expands , decreasing the velocity and pressure and thereby cooling the air even before the air interacts with the evaporator 16 . the cooled air also has a higher density . the passage of air across the evaporator fins is then maximized due to its lower velocity . the evaporator 16 is also configured to span a large surface area of the second chamber 14 in order to further maximize the amount of time the air spends passing over the evaporator fins and being further cooled . in one embodiment , the highly cooled air exiting the second chamber 14 is approximately 30 degrees fahrenheit lower than the incoming ambient air temperature . the changes in pressure , density , velocity and temperature prior to the ambient air interacting with the evaporator are all used to improve the efficiency of the evaporator to cool the helmet air exiting into the helmet by maximizing the amount of time the air is in contact with the evaporator cooling fins in the second chamber . once the air has passed over the cooling fins of the evaporator 16 , the air is drawn into a third chamber 18 — also known as a collection chamber — via the connected helmet blower 20 . in this third chamber 18 , the dense , highly cooled air experiences increased velocity as it passes through the helmet blower 20 and through a narrow adapter 22 to an air outtake opening 24 , or helmet air port , before entering the interior space of the helmet ( not shown ). it should be noted that the helmet blower 20 also operates to pull air into the cooling apparatus 100 in addition to pushing it out of the cooling apparatus 100 and into an interior space of the helmet . although similar in principle to refrigeration systems which liquefy the refrigerant gas as part of a cooling loop , the cooling system described herein does not change the physical state of the gas back to a liquid . without this control , the physical size of the evaporator would be much larger in order to achieve similar levels of temperature change . instead , this system rapidly cools the air , a gas , by reducing the velocity and pressure at a step in the cooling process before the cooled air is then sped back up by the blower and directed to the interior of the helmet . fig1 illustrates a perspective view of the cooling apparatus 100 when enclosed by a housing 26 , in accordance with one embodiment of the invention . the air inlet opening 2 and inlet air duct 4 are provided on a side portion of the cooling apparatus 100 for air to enter the unit from the ambient , or outside , environment . the filter cover 8 may also protrude from the housing 26 . on an upper right portion of the cooling apparatus 100 is the air outtake opening 24 where cooled air exits to the helmet . the housing 26 may provide a ventilated portion 28 to ventilate heat from the evaporator 16 fig2 illustrates a cross - sectional side view of the cooling apparatus 100 in accordance with one embodiment of the invention . the inlet air duct 4 is provided on the side portion of the cooling apparatus , and is in connection with the air inlet opening 2 . the incoming air passes through the air inlet opening 2 and into the inlet air duct 4 . the cross - sectional view in fig3 also illustrates a helmet air duct 7 situated in a central portion of the apparatus , as well as the air filter cover 8 disposed above the helmet air duct 7 , which serves as an inlet to the helmet air duct . fig2 also illustrates the location of a helmet blower 20 which drives air into the helmet through an adapter 22 connecting the collection chamber 18 and the helmet air port ( outlet opening ) 24 . fig3 illustrates a perspective cross - sectional view of the cooling apparatus 100 with arrows indicating the direction of air flow through the apparatus , in accordance with one embodiment of the invention . the air enters through the air inlet 2 ( arrow a ), where it then passes into the inlet air duct 2 , through a first opening 6 ( arrow b ) into the helmet air duct 7 in a central portion of the unit ( arrow c ) where it is first slightly cooled by the outer housing of the evaporator . the slightly - cooled air then passes into a filter cover 8 ( arrow d ) which contains the air filter ( not shown ), after which the filtered air is accelerated in the first chamber 10 ( arrow e ) to an expansion port ( narrow opening ) 12 . fig4 illustrates a separate perspective cross - sectional view of the cooling apparatus showing the passage of air into the second chamber 14 of the cooling apparatus ( arrow f ), particularly across the evaporator 16 ( arrows g ) and into the collection chamber 18 ( arrow h ). the accelerated air from the first chamber 10 passes through the narrow opening 12 and into the second chamber 14 , where it is expanded ( arrows g ) and slowed , and after which it passes across the evaporator 16 where it is cooled again to a temperature significantly lower than the outside ambient air temperature brought in through the air intake . the cooled air then passes from the second chamber 14 to the third chamber 18 . fig5 illustrates the pathway ( arrows i ) of cooled air through the cooling apparatus from the third chamber 18 into the adapter 22 and out of the cooling apparatus through the air outtake opening 24 to the interior of the helmet . fig6 a illustrates a top perspective view of the cooling apparatus 100 depicting an air filter inlet opening 30 and air filter outlet opening 32 of the helmet air duct 7 which connects with the air filter cover ( not shown ). the outlet opening 32 passes air from the air filter cover to a first chamber before it passes through the expansion valve ( narrow opening 12 ). fig6 b is a see - through illustration of the structures of the cooling apparatus which more clearly indicates the flow of air through the air filter and into the first chamber 10 , after which it passes down ( arrow e ) to the expansion valve 12 where the air then expands into the second chamber 14 ( arrow f ), otherwise known as the expansion chamber . the evaporator 16 is outlined in its central position within the second chamber 14 such that the expanded air in the second chamber 14 passes across the evaporator 16 ( arrows g ) and into the third chamber 18 ( arrow h ) before it passes through the helmet blower ( not shown ) ( arrow i ) and into the interior space of the helmet . fig7 a is a reverse perspective view of a left portion of the cooling apparatus 100 further indicating the location of the air inlet duct within the central portion of the cooling apparatus . the air inlet duct communicates with the air filter inlet opening 30 to pass air through the air filter and then out of the air filter outlet opening 32 to the first chamber 10 disposed along the left side portion of the cooling apparatus . once the air reaches the end of the first chamber 10 , the air is passed through the expansion valve and into the second chamber 14 , or the expansion chamber , where the air expands and is then cooled further by the evaporator ( not shown ). the cooled air then flows through the third chamber 18 and into the interior space of the helmet . fig7 b is a top perspective view illustration of the cooling apparatus 100 illustrating distinct shading of different structures within the cooling apparatus , including the first chamber 10 , second chamber 14 and third chamber 18 , and an outlet 24 to a helmet blower . fig7 c additionally illustrates an evaporator area 15 where the evaporator ( not shown ) is disposed in relation to the first chamber 10 , second chamber 14 and third chamber 18 . fig8 illustrates one embodiment of a method of cooling air for a helmet . the method comprises receiving air at a first air intake opening ( s 102 ) connected with a first chamber by an inlet air duct ; directing the air in the first chamber to a second chamber ( s 104 ) connected with the first chamber at a narrow opening , wherein the opening increases the pressure and decreases the velocity of air passing from the first chamber to the second chamber ; cooling the air in the second chamber ( s 106 ) with an evaporator to create cooled air ; collecting the cooled air in a third chamber ( s 108 ); and directing the cooled air to an interior portion of the helmet ( s 110 ) with a blower connected with the third chamber . the above description of disclosed embodiments is provided to enable any person skilled in the art to make or use the invention . various modifications to the embodiments will be readily apparent to those skilled in the art , the generic principals defined herein can be applied to other embodiments without departing from spirit or scope of the invention . thus , the invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principals and novel features disclosed herein .
a cooling apparatus for a helmet is provided for cooling air in an interior space of a helmet to cool a wearer &# 39 ; s head . the cooling apparatus maximizes the volume of air moving across an evaporator and minimizes the speed at which the air passes through cooling fins of the evaporator , thereby achieving air temperatures substantially below the outside ambient temperature . a narrow opening is provided between a first chamber of intake air and a second chamber which houses the evaporator , such that air passing through the narrow opening increases in velocity and pressure . upon entering the second chamber which is a large open space , the highly pressurized and high velocity air immediately slows down and expands into the large second chamber , where it then passes across a large surface area of the evaporator and outward through a collection chamber and a blower to the inside of the helmet .