Bob Bolland's Okinawa Rebreather Site

IDA-72 Switching Block

Switching Block

        The following description of the switching block or belt-block (the term "belt-block" has reference to the diver wearing the valve block attached to a belt near the front of the diver's body) has been taken and modified from Dave Sutton's IDA-72 Teardown pages:

        Here is the unique belt-block. As you can see, it is fed with a gas-line (the green-banded hose above) and two lines running back to the rig. The two obvious selector-valves here are lifted about 1/4 of an inch before they may be moved, and then move through about 120 degrees of arc. One simply purges the loop, offering a high-flow bypass of the internal mass-flow orifice. The other drives a pneumatic piston in the plenum chamber of the rig. When this valve is activated a piston moves about 1/2 inch and breaks the loop into two halves, thus making the rig an open-circuit system. The diver inhales from the auto-add valve and exhausts into the water through the normal exhaust valve. This instant conversion mode of the rig from a rebreather to an open-circuit system is VERY clever.

Switching Block
       This is a back-side view of the previous image.

Switching Block and Gas Hoses
       Illustrated here is the switching block and the three gas hoses which attach to the upper portion of the shell.

Gas Hoses for the Switching Block
       This image shows the three gas hoses where they enter the upper LH side of the inner shell.

NOTE: This page in re presentation with Bob Bolland's Okinawa Rebreather Site.

Page Date: 26 Mar '07
Page Modification Date: 26 Mar '07
Copyright © 2007 Robert F. Bolland