Continuous sample delivery peristaltic pump

An apparatus, comprising:

• a first disk, including:
• a first recess in the periphery of the first disk, the first recess configured to receive a first portion of tubing for conveying fluid,
• a first angular sector that has a nominal first radius and includes a first section of a periphery of the first disk, and
• a second angular sector that has a nominal second radius and includes a second section of the periphery of the first disk, wherein the second radius is smaller than the first radius, and wherein the first section of the periphery of the first disk is longer than the second section of the periphery of the first disk;
• a second disk that is substantially circular, has the nominal first radius, and includes a second recess in a periphery of the second disk, the second recess configured to receive a second portion of the tubing;
• a plurality of first rollers that are configured to orbit around the periphery of the first disk at a constant angular speed and configured to, when the first portion of the tubing is in the first recess, constantly press into contact with the periphery of the first disk, the tubing, or the periphery of the first disk and the tubing;
• and
• a plurality of second rollers that are configured to orbit around the periphery of the second disk at the constant angular speed and configured to, when the second portion of the tubing is in the second recess, constantly press into contact with the periphery of the second disk, the tubing, or the periphery of the second disk and the tubing, wherein:
• the first disk is configured such that each first roller moves in the first angular sector at a first tangential speed while fully compressing the tubing and such that each first roller moves in the second angular sector at a second tangential speed while fully compressing the tubing,
• the second disk is configured such that each second roller moves around the periphery of the second disk at the second tangential speed,
• the first disk, second disk, first rollers, and second rollers are configured to cause one first roller to fully compress the tubing while moving in the first angular sector and to simultaneously cause one second roller to fully compress the tubing while moving in a first section of the periphery of the second disk, and
• the first disk, second disk, first rollers, and second rollers are further configured to cause, after the one first roller has moved past the first angular sector, the one first roller to fully compress the tubing in the second angular sector and to simultaneously cause the one second roller to fully compress the tubing.