Protective Headgear

Abstract

A protective headgear includes two air chambers connected through a fan. Each air chamber has a fabric filter with a large surface area. A frame with a fan compartment and headband engages a person's head and forms a boundary to air flow around the head between the two air chambers. Air flows between the two air chambers primarily through the fan. One air chamber is formed above the head and is at lower pressure than air outside the headgear. Another air chamber is formed around the face and is at higher pressure than air outside the headgear. The fan draws air through a fabric filter to provide filtered air into the air chamber around the face, providing breathing volume and positive pressure protection. Exhaled air dissipates out of the headgear through a fabric filter forming part of the air chamber around the face.

What is claimed is: 
     
         1 . A protective headgear to be worn on a head of a person, comprising:
 a frame comprising a fan compartment and a headband, the headband having a front portion and a back portion and constructed and arranged to be worn on the head of the person;   a fan within the fan compartment;   a transparent face mask connected along an exterior edge or surface of the fan compartment;   a fabric bottom formed of a filtering fabric and connected along an edge of the transparent face mask and along a bottom portion of the frame, so as to form a first air chamber defined by the frame, the transparent face mask, and the fabric bottom, wherein the fabric bottom forms a lower filter surface;   a fabric top formed of a filtering fabric and connected on a top portion of the frame so as to form a second air chamber defined by the frame and the fabric top, wherein the fabric top forms an upper filter surface;   wherein when the protective headgear is worn, the headband engages the head and forms a boundary to air flow around the head between the first air chamber and the second air chamber, such that air flow between the first air chamber and the second air chamber is primarily through the fan; and   wherein when the fan is in operation while the headgear is being worn, the second air chamber is at lower pressure than air outside the protective headgear, and the first air chamber is at higher pressure than air outside the protective headgear, whereby the protective headgear provides filtered air through the upper filter surface from the second air chamber into the first air chamber to provide breathing volume for the person with positive pressure protection.   
     
     
         2 . The protective headgear of  claim 1  wherein the filtering fabric of the fabric top comprises a first layer of fabric and a second layer of fabric. 
     
     
         3 . The protective headgear of  claim 2 , wherein the filtering fabric comprises a first layer of cotton and a second layer of synthetic chiffon. 
     
     
         4 . The protective headgear of  claim 1 , wherein the fabric bottom has a large surface area to keep a low pressure drop across the filter fabric from the first air chamber to the air outside the protective headgear. 
     
     
         5 . The protective headgear of  claim 4 , wherein the low pressure drop is such that air is not pushed through the filtering fabric at high velocity. 
     
     
         6 . The protective headgear of  claim 1 , wherein the fan comprises a fan with low rotational velocity. 
     
     
         7 . The protective headgear of  claim 1 , wherein when the fan is operating while the protective headgear is worn, airflow through the fabric top, second air chamber, and fan into the first air chamber is matched with ventilation, moisture control, and positive pressure seal of the first air chamber. 
     
     
         8 . The protective headgear of  claim 1 , wherein the first air chamber has air volume such that when the person takes a breath, air pressure in the first air chamber does not change significantly so that breathed air is exhausted through the fabric bottom and replenished with filtered air by the fan. 
     
     
         9 . The protective headgear of  claim 1 , wherein the first air chamber has a volume of at least five liters. 
     
     
         10 . The protective headgear of  claim 1 , wherein a surface area of the filtering fabric of the fabric top and the fabric bottom is such that, when the fan is off while the protective headgear is being worn, enough air diffuses into the first air chamber to allow the person to breathe. 
     
     
         11 . The protective headgear of  claim 1 , wherein the fabric bottom forms a cloth tube hanging from the frame and the transparent face mask. 
     
     
         12 . The protective headgear of  claim 11 , wherein the cloth tube is much longer than a distance from the frame to shoulders of the person. 
     
     
         13 . The protective headgear of  claim 1 , wherein a seal around a neck of the person is formed by the fabric bottom. 
     
     
         14 . The protective headgear of  claim 13 , wherein the seal around the neck is formed by weight and folding of the fabric bottom. 
     
     
         15 . The protective headgear of  claim 14 , wherein the fabric bottom forms a cowl neck around the neck. 
     
     
         16 . The protective headgear of  claim 13 , wherein the fabric bottom comprises sufficient fabric to allow the person to scratch the face without breaking the seal around the neck. 
     
     
         17 . The protective headgear of  claim 13 , wherein the fabric bottom comprises sufficient fabric to allow the person to clean the transparent face mask without breaking the seal around the neck. 
     
     
         18 . The protective headgear of  claim 13 , wherein the fabric bottom comprises sufficient fabric to allow the person to touch, with a hand, an object in the first air chamber without breaking the seal around the neck, such that the filtering fabric remains between the hand and the object being touched. 
     
     
         19 . The protective headgear of  claim 13 , wherein the fabric bottom is flexible enough and the first air chamber has enough volume, so that the person can slip a hand completely inside the first air chamber without opening a significant area of the neck seal, and with minimal impact to air pressure in the first air chamber. 
     
     
         20 . A protective headgear comprising;
 a frame comprising a fan compartment and a headband, the headband constructed and arranged to be worn on the head of the person, the fan compartment connected to the headband and having an air inlet formed in a top portion of the frame and an air outlet formed in a bottom portion of the frame;   a fan arranged in the fan compartment such that in operation the fan draws air into the fan compartment through the air inlet and pushes air out the air outlet;   a transparent face mask connected to the frame;   a fabric bottom formed of a first filtering fabric and connected along an edge of the transparent face mask and along the bottom portion of the frame, so as to form a first air chamber receiving air from the air outlet and defined by the frame, the transparent face mask, and the fabric bottom, wherein the fabric bottom forms a lower filter surface; and   a fabric top formed of a second filtering fabric and connected on a top portion of the frame so as to form a second air chamber providing air to the air inlet and defined by the frame and the fabric top, wherein the fabric top forms an upper filter surface.