end fittings 165 can be mounted to the body 153 by any sufficient means in the present invention mounting bolts 167 are utilized at least one end fitting 165 is also provided with internal threads 169 to facilitate connecting the isolation valve 27 to the feed tube assembly 15 by the threaded extension 113 on the second seal assembly 109 it is understood that any other convenient means of connecting the isolation valve to the feed tube assembly is within the scope of the present invention a stem assembly 171 and handle 173 are provided for actuating the isolation valve 27 the handle 173 is releasably secured to the stem assembly 171 by a nut 175 that clamps to the tip of a packing nut 177 and also helps to support the ball 157 in the body 153 the ball 157 is supported in the passageway 155 such that the ball can shift axially along the passageway the ball valve 151 can be manually actuated with the handle 173 or an actuator not shown may be provided to actuate the valve the positions of the handle 173 and the ball 157 are limited by a depending catch member 179 carried by the handle the catch member 179 engages a surface of the body 153 to provide fixed stops for the isolation valve 27 the structure of the isolation valve as described above reflects a preferred embodiment it will be readily apparent to those skilled in the art that changes and additions to the.