second rings 1406 1410 spaced from each other on a solid base pipe 1404 an elastomer material may form the bladder element 1408 which can optionally be biased against a predetermined force caused by the annular pressure 1402 for some embodiments the first ring 1406 slides along the base pipe 1404 to further enable compression and expansion of the bladder element 1408 in operation increasing the annular pressure 1402 to a predetermined level compresses the bladder element 1408 against the base pipe 1404 to force fluid contained by the bladder element 1408 to the ddv 1400 the lower bladder assembly 1417 includes a bladder element 1426 a biasing band 1424 that biases the bladder element 1426 against a predetermined force caused by the bore pressure and an outer shroud 1422 that are all disposed between first and second rings 1420 1430 spaced from each other on a perforated base pipe 1404 the pressure in a bore 1434 of the bladder assembly 1417 acts on a surface of the bladder element 1426 due to apertures 1428 in the perforated base pipe that also aid in protecting the bladder element 1426 from damage as tools pass through the bore 1434 in operation increasing the.