Flow rate control of temperature control fluids

An apparatus comprising:

• a housing,
• a fluid flow passage for flow of a filtered temperature control fluid through the housing,
• a length of filter material having a length portion extending across an upstream end of the flow passage for filtering undesirable material from the fluid,
• a fan means for causing fluid flow through the length portion and along the flow passage, the fan means having at least one fan disposed downstream in the flow passage from the length portion of the filter material,
• filter advancement means, and
• control means, actuable upon reaching an undesirably low rate of fluid flow through the length portion as determined by a drag effect created upon a rotational speed of the fan, to operate the advancement means so as to advance the length of filter material for a distance longitudinally to move at least some of the length portion from the upstream end of the flow passage and move unused filter material across the upstream end of the flow passage thereby to increase fluid flow through the filter material above the undesirably low rate.

An apparatus comprising:

• a housing,
• a fluid flow passage for flow of a filtered temperature control fluid through the housing,
• a length of filter material having a length portion extending across an upstream end of the flow passage for filtering undesirable material from the fluid,
• means for causing fluid flow through the length portion and along the flow passage,
• filter advancement means, and
• control means, actuable upon reaching an undesirably low rate of fluid flow through the length portion as determined by an amount of flex of the length portion of filter material, to operate the advancement means so as to advance the length of filter material for a distance longitudinally to move at least some of the length portion from the upstream end of the flow passage and move unused filter material across the upstream end of the flow passage thereby to increase fluid flow through the filter material above the undesirably low rate.

An apparatus comprising:

• a housing,
• a fluid flow passage for flow of a filtered temperature control fluid through the housing,
• a length of filter material having a length portion extending across an upstream end of the flow passage for filtering undesirable material from the fluid,
• means for causing fluid flow through the length portion and along the flow passage,
• filter advancement means, and control means, actuable upon reaching an undesirably low rate of fluid flow through the length portion as determined by a temperature in a downstream region of the fluid flow passage, to operate the advancement means so as to advance the length of filter material for a distance longitudinally to move at least some of the length portion from the upstream end of the flow passage and move unused filter material across the upstream end of the flow passage thereby to increase fluid flow through the filter material above the undesirably low rate.