US Patent 11208873 Switch sub with two way sealing features and method

A switch sub adapter configured to connect a switch sub to a perforating gun assembly. The switch sub adapter includes a tubular body having first threads that connect to the switch sub and second threads that connect to the perforating gun assembly; a first internal chamber formed at a first end of the adapter; a second internal chamber formed at a second end of the adapter; a conduit connecting the first internal chamber to the second internal chamber; and a dart having a tip located in the conduit and a base part located in the second internal chamber. The dart is formed from a compliant material that deforms in response to pressure resulting from detonation of charges associated with the perforating gun.