Abstract: To reduce the torque required to turn a movable upstream disk relative to an abutting stationary downstream disk in a multiple orifice valve, particularly when the disks are subjected to high fluid pressures, there is provided a removable sleeve or insert at the outlet side of the stationary downstream disk having a support member formed therein for supporting the downstream or outlet side of the downstream disk. The support member may be provided with a central raised portion for supporting the downstream side of the stationary downstream disk along the central axis thereof which is coaxial with the central rotational axis of the movable upstream disk. The supportive sleeve or insert serves to reduce the torque required to turn the upstream disk irrespective of the diameter of the disks. Such a sleeve further reduces the required turning torque in such valve assemblies wherein the abutting faces of the disks are polished to a high level of surface finish quality.