Air bladder type vent valve for use in an hydraulic oil tank of an enclosed hydraulic transmission system

Abstract

Air bladder type vent valve is disclosed having an air bladder fastened to the air vent of the hydraulic oil tank of an enclosed hydraulic transmission system, for example, hydraulic jack and suspended inside the hydraulic oil tank, and a fastening device, which affixes the air bladder to the periphery of the air vent in an airtight status to keep the inside space of the air bladder in air communication with the atmosphere so that the inside pressure of the hydraulic oil tank is maintained in balance with the atmosphere during the operation of the enclosed hydraulic transmission system to pump hydraulic fluid in and out of the hydraulic oil tank.

1 . An air bladder type vent valve comprising a hydraulic oil tank installed in an enclosed hydraulic transmission system to hold a hydraulic fluid, said hydraulic oil tank having an air vent, and a vent valve mounted in said air vent for guiding in air from the atmosphere, wherein said vent valve comprises an air bladder suspended inside said hydraulic oil tank, said air bladder having a mouth connected to said air vent for guiding in outside atmospheric air, and fastening means affixing said air bladder to the periphery of said air vent in an airtight status to keep the inside space of said air bladder in air communication with the atmosphere.  
   
   
       2 . The air bladder type vent valve as claimed in  claim 1 , wherein said air bladder is made of a soft airtight material.  
   
   
       3 . The air bladder type vent valve as claimed in  claim 1 , wherein said air bladder is an inflatable bag made of a flexible airtight material.  
   
   
       4 . The air bladder type vent valve as claimed in  claim 1 , wherein said fastening means comprises an outer mounting ring sealed to said air vent, and an inner mounting ring fastened to said outer mounting ring to seal the periphery of the mouth of said air bladder to said outer mounting ring.  
   
   
       5 . The air bladder type vent valve as claimed in  claim 4 , wherein said inner mounting ring is a rubber seal ring.  
   
   
       6 . The air bladder type vent valve as claimed in  claim 1 , wherein said air bladder has at least one rib formed integral with an inside wall of said mouth.