Ventilated helmet preventing deposition of fog on a protective eyewear, and a method and use of the same

Abstract

A ventilated helmet is provided. The helmet includes a shell defining a cavity, the shell having a front section provided with an opening to allow the wearer to see. The helmet also includes a transparent shield adapted having an inner surface and being adapted to substantially close the opening. Finally, the helmet includes a ventilation system having an evacuation subsystem adapted to create an evacuation airflow to evacuate humid air within the cavity to a surrounding environment. The ventilation system further has a pressurizing subsystem adapted to admit a pressurizing airflow within the cavity to create a high-pressure zone and a low-pressure zone within the cavity, wherein when in use, the wearer exhales air within the low-pressure zone, and wherein the high-pressure zone prevents air within the cavity from travelling from the low-pressure zone to the high-pressure zone. A method of evacuating humid air from the cavity is also provided.

1 . A helmet with a shell defining a cavity, the helmet comprising:
 a ventilation channel extending laterally along the shell and adapted to enable fluid flow therealong, the ventilation channel having a converging-diverging section;   a first ventilation inlet adapted to establish fluid communication between the cavity and the ventilation channel;   a second ventilation inlet adapted to establish fluid communication between a surrounding environment and the ventilation channel upstream of the first ventilation inlet, the converging-diverging section being configured to create a vacuum to urge air from within the cavity into the ventilation channel through the first ventilation inlet; and   a ventilation outlet adapted to establish fluid communication between the ventilation channel and the surrounding environment.   
     
     
         2 . The helmet of  claim 1 , wherein at least one of the first and second ventilation inlets are positioned upstream of the converging-diverging section. 
     
     
         3 . The helmet of  claim 1 , wherein both the first and second ventilation inlets are positioned upstream of the converging-diverging section. 
     
     
         4 . The helmet of  claim 1 , wherein a distance between the first ventilation inlet and the ventilation outlet is less than a distance between the second ventilation inlet and the ventilation outlet. 
     
     
         5 . The helmet of  claim 1 , wherein the converging-diverging section comprises a converging portion and a diverging portion, and wherein the converging portion is at least partially defined upstream of the first ventilation inlet, and the diverging portion is at least partially defined downstream of the first ventilation inlet. 
     
     
         6 . The helmet of  claim 1 , wherein at least a portion of the ventilation channel is defined by an inner surface of the shell, an outer surface of the shell or a combination thereof. 
     
     
         7 . The helmet of  claim 1 , wherein the ventilation channel is at least partially defined in a thickness of the shell. 
     
     
         8 . The helmet of  claim 1 , wherein a portion of the ventilation channel located between the second ventilation inlet and the ventilation outlet protrudes from the shell. 
     
     
         9 . The helmet of  claim 1 , wherein the ventilation system comprises left and right ventilation channels extending on respective sides of the helmet, the left and right ventilation channels comprising left and right first ventilation inlets, left and right ventilation outlets, left and right second ventilation inlets and left and right converging-diverging sections, respectively. 
     
     
         10 . A helmet with a shell defining a cavity, the helmet comprising:
 a ventilation channel extending laterally along the shell and adapted to enable airflow therealong, the ventilation channel comprising a converging-diverging section;   a first ventilation inlet adapted to establish fluid communication between the cavity and the ventilation channel to admit an evacuation airflow containing air from within the cavity into the ventilation channel;   a second ventilation inlet adapted to establish fluid communication between a surrounding environment and the ventilation to admit a vacuum-generating airflow into the ventilation channel, the vacuum-generating airflow being configured to urge the evacuation airflow into the ventilation channel, the converging-diverging section of the ventilation channel being configured to increase a velocity of the vacuum-generating airflow; and   a ventilation outlet adapted to establish fluid communication between the ventilation channel and the surrounding environment to expel the evacuation airflow and the vacuum-generating airflow.   
     
     
         11 . The helmet of  claim 10 , wherein the second ventilation inlet is upstream of the first ventilation inlet, and the first ventilation inlet is defined along the ventilation channel at least partway between the second ventilation inlet and the ventilation outlet. 
     
     
         12 . The helmet of  claim 10 , wherein at least one of the first and second ventilation inlets are positioned upstream of the converging-diverging section. 
     
     
         13 . The helmet of  claim 10 , wherein both the first and second ventilation inlets are positioned upstream of the converging-diverging section. 
     
     
         14 . The helmet of  claim 10 , wherein a distance between the first ventilation inlet and the ventilation outlet is less than a distance between the second ventilation inlet and the ventilation outlet. 
     
     
         15 . The helmet of  claim 10 , wherein at least a portion of the ventilation channel is defined by an inner surface of the shell, an outer surface of the shell or a combination thereof. 
     
     
         16 . The helmet of  claim 10 , wherein the ventilation channel is at least partially defined in a thickness of the shell. 
     
     
         17 . The helmet of  claim 10 , wherein a portion of the ventilation channel located between the second ventilation inlet and the ventilation outlet protrudes from the shell. 
     
     
         18 . The helmet of  claim 10 , wherein the ventilation system comprises left and right ventilation channels extending on respective sides of the helmet, the left and right ventilation channels comprising left and right ventilation inlets, left and right ventilation outlets, left and right second ventilation inlets and left and right converging-diverging sections, respectively. 
     
     
         19 . A helmet with a shell defining a cavity, the helmet comprising:
 a ventilation channel extending laterally along the shell and adapted to enable airflow therealong;   a first ventilation inlet defined inside the shell and adapted to establish fluid communication between the cavity and the ventilation channel to admit an evacuation airflow containing air from within the cavity into the ventilation channel;   a second ventilation inlet provided on an outer surface of the shell and adapted to establish fluid communication between a surrounding environment and the ventilation channel to admit a vacuum-generating airflow into the ventilation channel to urge an admission of the evacuation airflow into the ventilation channel; and   a ventilation outlet provided on the outer surface of the shell and adapted to establish fluid communication between the ventilation channel and the surrounding environment to enable the evacuation airflow and the vacuum-generating airflow to exit the evacuation channel, wherein the first ventilation inlet is defined along the ventilation channel at least partway between the second ventilation inlet and the ventilation outlet.   
     
     
         20 . The helmet of  claim 19 , wherein the ventilation channel comprises a converging-diverging section defined at least partway between the second ventilation inlet and the ventilation outlet and configured to increase a velocity of at least one of the vacuum-generating airflow and the evacuation airflow.