Check valve and bag having the same

Abstract

A check valve that allows opening of the fluid path by hand alone, that is capable of passing a fluid in a simple and quick manner, that keeps the appearance of the check valve unaffected, and that are unlikely to result in accidental fluid leakages, and a bag equipped with the check valve are provided. The check valve comprises handling portions with less flexibility than the exterior sheets, the handling portions being formed at an opening portion on the manual opening side of the fluid path, wherein the fluid path can be manually opened by pinching and squeezing the handling portions to come close each other.

1 . A check valve comprising exterior sheets and a valve portion sheet, both of which are made of flexible resin sheets and placed one on top of another such that the valve portion sheet is sandwiched between the exterior sheets, and side seals that are formed by bonding the opposing exterior sheets along both sides thereof, whereby a fluid path being flat and substantially cylindrical in cross section is provided thereinside, the valve portion sheet having a mounting surface on one side and a contacting surface on the other side, the mounting surface including a bonding portion that is attached to one of the exterior sheet, the contacting surface being movable toward or away from the other exterior sheet that is opposite thereto or a valve portion sheet that is attached to the other exterior sheet, the fluid path being closed by the contacting surface in close contact with the other exterior sheet or the valve portion sheet opposing to the contacting surface, wherein 
 handling portions are formed at an opening on the manual opening side of both opening portions and have less flexibility than the respective exterior sheets, whereby    the fluid path can be opened in such a manner as to manually pinch the handling portions and squeeze them toward the exterior sheets in order to come close each other.    
   
   
       2 . The check valve of  claim 1 , wherein the exterior sheets are designed to be equally thick or thicker than the valve portion sheet.  
   
   
       3 . The check valve of  claim 1 , wherein a contact preventing portion is provided on at least part of the portion other than the bonding portion on the mounting surface of the valve portion sheet to prevent close contact between the valve portion sheet and the exterior sheet where the valve portion sheet is attached in order to avoid a decline in the checking action.  
   
   
       4 . The check valve of  claim 1 , wherein the sum of the length in width of the handling portions at an opening on the manual opening side being defined from the edge neighboring the opening to the other edge is equal to or more than 5 mm.  
   
   
       5 . A bag with a check valve, the bag being constituted of bag sheets that are made of flexible resin sheets and capable of blocking the circulation of fluid between the inside and outside thereof, the check valve having a closable fluid path that communicates between the inside and outside the bag, wherein 
 the check valve comprises exterior sheets and a valve portion sheet, both of which are made of flexible resin sheets and placed one on top of another such that the valve portion sheet is sandwiched between the exterior sheets, and side seals that are formed by bonding the opposing exterior sheets along both sides thereof, whereby said fluid path being flat and substantially cylindrical in cross section is provided thereinside, the valve portion sheet having a mounting surface on one side and a contacting surface on the other side, the mounting surface including a bonding portion that is attached to one of the exterior sheet, the contacting surface being movable toward or away from the other exterior sheet that is opposite thereto or a valve portion sheet that is attached to the other exterior sheet, the fluid path being closed by the contacting surface in close contact with the other exterior sheet or the valve portion sheet opposing to the contacting surface, wherein    handling portions are formed at an opening on the manual opening side of both opening portions and have less flexibility than the respective exterior sheets, whereby    the fluid path can be opened in such a manner as to manually pinch the handling portions and squeeze them toward the exterior sheets in order to come close each other.    
   
   
       6 . The check valve of  claim 2 , wherein a contact preventing portion is provided on at least part of the portion other than the bonding portion on the mounting surface of the valve portion sheet to prevent close contact between the valve portion sheet and the exterior sheet where the valve portion sheet is attached in order to avoid a decline in the checking action.  
   
   
       7 . The check valve of  claim 2 , wherein the sum of the length in width of the handling portions at an opening on the manual opening side being defined from the edge neighboring the opening to the other edge is equal to or more than 5 mm.  
   
   
       8 . The check valve of  claim 3 , wherein the sum of the length in width of the handling portions at an opening on the manual opening side being defined from the edge neighboring the opening to the other edge is equal to or more than 5 mm.