<p>PCT No. PCT/GB94/01064 Sec. 371 Date Dec. 19, 1995 Sec. 102(e) Date Dec. 19, 1995 PCT Filed May 18, 1994 PCT Pub. No. WO94/27070 PCT Pub. Date Nov. 24, 1994A selector valve includes an annular body having a sealing surface having a plurality of inlet ports. The sealing head carries a seal member which is urged by a spring against the sealing surface. The sealing member has a sealing face comprising a central band and lateral areas above and below the central band. The lateral areas are reduced in size compared to the area of the central band to equalize wear of the sealing member.</p>
