Filter structure of igniter

Abstract

A filter structure for an ignitor is provided, in which a flame length is kept uniform by ensuring constant gas permeability and ease of assembly of the filter is achieved. When causing ejection and combustion of fuel gas, which is contained in a tank chamber ( 24 ), out of a discharge nozzle ( 3 ) via a filter ( 71 ) which serves to keep the gas passage rate flowing therethrough constant and a valve mechanism ( 4 ) for starting and stopping feeding of the gas, the filter ( 71 ) is made of a membrane film ( 71 a ), which has pores and serves to keep the passage rate of the gas flowing therethrough constant; and a permeable porous body ( 71 b ) placed on the membrane film. A filter component ( 7 ) for affixing the filter ( 71 ) to the holder ( 72 ) is assembled on the upstream side of the valve mechanism ( 4 ). The holder ( 72 ) has a centrally formed vent hole ( 72 c ), the filter ( 71 ) is welded to the holder along the peripheral edge of the vent hole ( 72 c ), and the membrane ( 71 a ) and porous body ( 71 b ) of the filter are not joined together within the region corresponding to the region within the vent hole ( 72 c ) of the holder.

1 . In an ignitor for causing ejection and combustion of fuel gas, which is contained in a tank chamber, out of a discharge nozzle via a filter which serves to keep the gas passage rate flowing therethrough constant and a valve mechanism for starting and stopping feeding of the gas, 
 a filter structure characterized in that the filter comprises a membrane film, which has pores and serves to keep the passage rate of the gas flowing through the filter constant, and a permeable porous body placed on the membrane film; a filter component for affixing the filter to a holder is assembled on the upstream side of the valve mechanism; the holder has a centrally formed vent hole; the filter is welded to the end face of the disk portion along the peripheral edge of the vent hole; and the membrane and porous body of the filter are not joined together within the region corresponding to the region within the vent hole of the holder.    
   
   
       2 . The filter structure of the ignitor as defined in  claim 1 , characterized in that the porous body of the filter is positioned on the valve mechanism side.  
   
   
       3 . The filter structure of the ignitor as defined in  claim 1  or  2 , characterized in that the porous body of the filter is nonwoven fabric composed of synthetic resin.  
   
   
       4 . The filter structure of the ignitor as defined in  claim 1  or  2 , characterized in that the porous body of the filter is mesh material composed of synthetic resin.  
   
   
       5 . The filter structure of the ignitor as defined in  claim 1  or  2 , characterized in that the filter comprises a membrane film; and porous bodies placed on opposite sides of the membrane film.  
   
   
       6 . The filter structure of the ignitor as defined in  claim 1  or  2 , characterized in that the holder comprises: a disk portion having a centrally formed vent hole; and a tubular portion, wherein the filter is welded to the end face of the disk portion along the peripheral edge of the vent hole, a part of the valve mechanism is inserted into the tubular portion, an O-ring is provided at one end of the tubular portion for hermetically sealing, and gas passage rate is determined by the vent hole size.  
   
   
       7 . The filter structure of the ignitor as defined in  claim 1  or  2 , characterized in that the porous body of the filter is always in contact with a part of the valve mechanism.  
   
   
       8 . The filter structure of the ignitor as defined in  claim 7 , characterized in that a degree of tensioning of the filter is controlled by changing the contact position, which is brought in contact with the porous member of the filter, at a part of the valve mechanism, thereby making fine adjustments of the gas passage rate through the filter.  
   
   
       9 . The filter structure of the ignitor as defined in  claim 1 , characterized by further comprising a resilient body, the resilient body being provided within the filter at a position closer to on the tank chamber.  
   
   
       10 . The filter structure of the ignitor as defined in  claim 1 , characterized in that one end of the valve mechanism is inserted into the holder to which the filter is affixed, the outer peripheral surface of the valve mechanism at the end thereof, the inner peripheral surface of the holder approach one another, and the volume of the space defined therebetween is small.