Check valve, sealing bag, and production methods for both

Abstract

To provide a check valve and a sealing bag that are high in certainty of the checking effect and prevented as much as possible from increasing in the production cost. A check valve V includes base sheets 31 and 32 , made of a flexible resin, and a plurality of valve body sheets 4 , at least two of the valve body sheets 4 , that is, an upstream valve body sheet 4 a and a downstream valve body sheet 4 b form a single set and both are adhered to one base sheet 31 , the adhesion of the upstream valve body sheet 4 a to the one base sheet 31 is achieved at an upstream end 4 a 1 side with a downstream end 4 a 2 side being movable with respect to the base sheets 31 and 32 , the adhesion of the downstream valve body sheet 4 b is achieved at a downstream end 4 b 2 side with an upstream end 4 b 1 side being movable with respect to the base sheets 31 and 32 , and the respective ends 4 a 2 and 4 b 1 of the valve body sheets 4 a and 4 b at the sides made movable with respect to the base sheets 31 and 32 are closely contactable with the other base sheet 32.

1 . A check valve formed by overlapping a plurality of sheets, having a gas flow passage space, which is a space through which gas passes, formed between the sheets, and being capable of allowing passage of gas flow in a positive direction from an inlet to an outlet and blocking gas flow in a reverse direction from the outlet to the inlet by opening and closing of the gas flow passage space,
 wherein the check valve is comprised of a plurality of base sheets made of resin, and a plurality of flexible valve body sheets made of resin;   the plurality of base sheets being disposed to face each other in a front/back direction,   at least two sheets of the plurality of valve body sheets forming a single set comprising an upstream valve body sheet disposed at an upstream side and a downstream valve body sheet disposed at a downstream side on a basis of the positive gas flow direction,   each of the valve body sheets that forms the single set being adhered to at least one base sheet,   the adhesion being achieved so that the respective valve body sheets are aligned in series in a gas flow direction during evacuation and so as not to be overlapped in the front/back direction,   the adhesion of the upstream valve body sheet to the one base sheet being achieved at an upstream end side with a downstream end side being made movable with respect to the base sheets,   the adhesion of the downstream valve body sheet being achieved at a downstream end side with an upstream end side being movable with respect to one base sheet, and   at least a portion of the single set of valve body sheets being capable of contacting closely and separating with respect to another base sheet or with respect to a valve body sheet different from the single set of valve body sheets and disposed on the opposite side of the one base sheet across the single set of valve body sheets, thereby allowing passage of gas flow in the positive direction and block gas flow in the reverse direction.   
     
     
         2 . The check valve according to  claim 1 , wherein
 a portion of the one base sheet is arranged as a gas flow passage portion having gas permeability of allowing gas flow in the positive direction to pass through in the front/back direction,   the gas flow passage portion being an inlet through which the gas flow in the positive direction flows into the check valve, and   the gas flow passage portion being disposed at a position of the one base sheet that is further upstream than a position matching the upstream end of the upstream valve body sheet in the front/back direction.   
     
     
         3 . The check valve according to  claim 2 , wherein
 the one base sheet comprises the gas flow passage portion and another portion, the another portion having gastightness.   
     
     
         4 . The check valve according to  claim 1 , wherein
 the outlet through which gas flow in the positive direction flows out from the inside of the check valve is disposed at other base sheet side,   the outlet being formed by making the other base sheet smaller than the one base sheet or by providing an opening in the other base sheet, and   the outlet being disposed at a position of the one base sheet that is further downstream than a position matching the downstream end of the upstream valve body sheet in the front/back direction.   
     
     
         5 . The check valve according to  claim 4 , wherein
 a bent seal is formed between the inlet and the outlet,   the bent seal being adhesion of the one base sheet, the valve body sheets, and the other base sheet in the front/back direction, and   the bent seal shaping bent so that a flow path inside the check valve from the inlet to the outlet becomes a zigzagging flow path in a plan view of the sheets.   
     
     
         6 . The check valve according to  claim 5 , wherein
 a silicone liquid or other inert substance is disposed inside a flow path, defined by the bent seal, between the valve body sheets and the other base sheet.   
     
     
         7 . The check valve according to  claim 1 , wherein
 the one base sheet has gas permeability across its entire surface,   a portion of the gas-permeable one base sheet is arranged as a gas flow passage portion through which gas flow in the positive direction passes in the front/back direction,   the gas flow passage portion being a portion of the one base sheet that is further upstream than a position matching the upstream end of the upstream valve body sheet in the front/back direction.   
     
     
         8 . The check valve according to  claim 2 , wherein
 the gas flow passage portion of the one base sheet is provided with a nonwoven fabric.   
     
     
         9 . The check valve according to  claim 1 , wherein
 the one base sheet is made of a nonwoven fabric having gas permeability across its entire surface,   a portion of the gas-permeable one base sheet is arranged as a gas flow passage portion through which gas flow in the positive direction passes in the front/back direction,   a portion of the one base sheet except the gas flow passage portion being covered by a covering sheet having gastightness.   
     
     
         10 . The check valve according to  claim 1 , wherein the check valve is used by being fixed to a sealing bag having an article containing portion, the article containing portion being capable of ventilation to the outside of the bag to evacuate gas present in the article containing portion to the outside of the bag. 
     
     
         11 . A sealing bag having the check valve according to  claim 4  fixed thereto,
 wherein the sealing bag is comprised of a flexible bag sheet made of resin, 
 the bag sheet being adhered so that a portion except an article receiving opening and a portion to which the check valve is fixed is separated in a gastight manner from the outside of the bag, and 
 a whole perimeter of the check valve is adhered to an inner side or an outer side of the bag sheet. 
 
     
     
         12 . A sealing bag having the check valve according to  claim 7  fixed thereto,
 wherein the sealing bag is comprised of a flexible bag sheet made of resin, 
 the bag sheet being adhered so that a portion except an article receiving opening and a portion to which the check valve is fixed is separated in a gastight manner from the outside of the bag, 
 the check valve, sandwiched by the bag sheet, having an upstream end positioned inside the article containing portion and a downstream end positioned outside the article containing portion on a basis of a gas flow direction during evacuation, 
 a portion at an upstream end side of the other base sheet of the check valve being adhered to a surface of the bag sheet that is an inner surface facing the other base sheet, 
 a gas flow passage portion of the one base sheet of the check valve being exposed to a space in the article containing portion that is capable of containing an article, 
 a lateral direction seal being formed by adhesion of the bag sheet, 
 the lateral direction seal being formed to traverse the check valve in a width direction, 
 a longitudinal direction seal being formed additionally by the adhesion of the bag sheet, 
 the longitudinal direction seal being in a direction intersecting the lateral direction seal and extended more to the upstream side than the lateral direction seal on a basis of a gas flow direction during evacuation inside the check valve, 
 the longitudinal direction seal being provided sandwiching the check valve and being spaced by an interval wider than a width dimension of the check valve to form a single set by two, and 
 an upstream end of the longitudinal direction seal being positioned further upstream, on a basis of the gas flow direction during evacuation inside the check valve, than a lower end of a portion, of the gas flow passage portion in the one base sheet, which is defined by the lateral direction seal and through which air practically flows. 
 
     
     
         13 . A method for producing the check valve according to  claim 1 , wherein elongate sheets supplied continuously in a longitudinal direction are used as the base sheet and the valve body sheet, and
 the respective valve body sheets forming a single set are supplied as a single elongate sheet that is thereafter cut in two in a width direction and overlapped with the one base sheet.   
     
     
         14 . A method for producing a sealing bag having a check valve fixed thereto,
 wherein the check valve is comprised of flexible base sheets made of resin; and a plurality of valve body sheets,   one base sheet of the base sheets has gas permeability across its entire surface,   the base sheets are disposed to face each other in a front/back direction,   at least two sheets of the plurality of valve body sheets forming a single set comprising an upstream valve body sheet disposed at an upstream side and a downstream valve body sheet disposed at a downstream side on a basis of a gas flow direction during evacuation,   each of the valve body sheets that forms the single set are adhered at least to the one base sheet,   the adhesion is achieved so that the respective valve body sheets are aligned in series in the gas flow direction during evacuation and so as not to be overlapped in the front/back direction,   the adhesion of the upstream valve body sheet to the one base sheet is achieved at an upstream end side with a downstream end side being made movable with respect to the base sheets,   the adhesion of the downstream valve body sheet is achieved at a downstream end side with an upstream end side being movable with respect to the base sheets, and   the respective ends of the valve body sheets that are made movable with respect to the base sheets are capable of closely contacting the other base sheet or a valve body sheet that is different from the valve body sheets forming the single set and is adhered to the other base sheet; and   a flexible elongate sheet made of resin and supplied continuously in a longitudinal direction is used as a bag sheet,   the method for producing a sealing bag comprising the steps of:   sandwiching the check valve by the bag sheet;   forming a lateral direction seal traversing the check valve in a width direction by adhesion of the bag sheet; and   forming a longitudinal direction seal by adhesion of the bag sheet;   the longitudinal direction seal formed in the steps, being in a direction intersecting the lateral direction seal and extended more to the upstream side on the basis of the gas flow direction during evacuation inside the check valve than the lateral direction seal,   the longitudinal direction seal being provided sandwiching the check valve and spaced by an interval wider than a width dimension of the check valve to form a single set by two, and   an upstream end of the longitudinal direction seal being positioned further upstream, on a basis of the gas flow direction during evacuation inside the check valve, than a lower end of a portion, of the gas flow passage portion in the one base sheet, which is defined by the lateral direction seal and through which air practically flows.