height 48 in a z direction a length 50 in an x direction and a width 52 in a y direction inlet and outlet ports 54 are formed in an upper surface 56 of the fluid connecting block 18 a passage 60 is drilled into an end surface 62 and interconnects lower portions of the ports 54 the passage 60 is closed off at the surface 62 a fluid connecting passage is thereby jointly defined by lower portions of openings forming the ports 54 and the passage 60 a gas can thus flow into one of the ports 54 through the fluid connecting block 18 and exit through the other port 54 four cradle alignment pins 64 stand proud of a lower surface of the fluid connecting block 18 referring again to fig1 the fluid connecting blocks 18 are inserted into the locator alignment cradles 14 the fluid connecting block 18 to the left has a left portion which is located on the locator alignment cradle 14 to the left and a right portion which is located on the locator alignment cradle 14 in the middle the fluid connecting block 18 in the middle is held jointly by the locator alignment cradles 14 in the middle and to the right the width 52 in fig3 of each fluid connecting block 18 matches the distance in a y direction 38 in fig2 and defined by the locator alignment cradles 14 so that the fluid connecting blocks 18 are prevented from movement in a y direction and in u2296 in an x y plane about a z axis the cradle alignment pins 64 in.