A fluid flow chamber cassette that can be mounted with either its front wall or rear wall against a supporting machine and has a flexible tube that extends from a sidewall and forms a loop that is symmetrical about a loop axis that is transverse to the side wall so that the loop will be acted upon by a pump roller on the machine both when the front wall is against the machine and when the rear wall is against the machine. Also disclosed is automatically fixing the initial liquid levels and amounts of air in venous and arterial chambers of fluid flow transfer device apparatus by having the arterial chamber inlet enter the arterial chamber at a position higher than the arterial chamber outlet, having the venous chamber inlet enter the venous chamber at a position higher than the venous chamber outlet, and priming the apparatus by causing reverse flow, so that the liquid rises in the venous and arterial chambers to the level of the entrances of the inlets. Also disclosed is sensing pressure of fluid in a fluid flow chamber by placing an impermeable flexible diaphragm over a hole in a rigid wall of the fluid flow chamber, providing a second chamber on the other side of the diaphragm, and sensing the pressure in the second chamber.

A fluid flow chamber cassette that can be mounted with either its front wall or rear wall against a supporting machine and has a flexible tube that extends from a sidewall and forms a loop that is symmetrical about a loop axis that is transverse to the side wall so that the loop will be acted upon by a pump roller on the machine both when the front wall is against the machine and when the rear wall is against the machine. Also disclosed is automatically fixing the initial liquid levels and amounts of air in venous and arterial chambers of fluid flow transfer device apparatus by having the arterial chamber inlet enter the arterial chamber at a position higher than the arterial chamber outlet, having the venous chamber inlet enter the venous chamber at a position higher than the venous chamber outlet, and priming the apparatus by causing reverse flow, so that the liquid rises in the venous and arterial chambers to the level of the entrances of the inlets. Also disclosed is sensing pressure of fluid in a fluid flow chamber by placing an impermeable flexible diaphragm over a hole in a rigid wall of the fluid flow chamber, providing a second chamber on the other side of the diaphragm, and sensing the pressure in the second chamber.

A fluid flow chamber cassette that can be mounted with either its front wall or rear wall against a supporting machine and has a flexible tube that extends from a sidewall and forms a loop that is symetrical about a loop axis that is transverse to the side wall so that the loop will be acted upon by a pump roller on the machine both when the front wall is against the machine and when the rear wall is against the machine. Also disclosed is automatically fixing the initial liquid levels and amounts of air in venous and arterial chambers of fluid flow transfer device apparatus by having the arterial chamber inlet enter the arterial chamber at a position higher than the arterial chamber outlet, having the venous chamber inlet enter the venous chamber at a position higher than the venous chamber outlet, and priming the apparatus by causing reverse flow, so that the liquid rises in the venous and arterial chambers to the level of the entrances of the inlets. Also disclosed is sensing pressure of fluid in a fluid flow chamber by placing an impermeable flexible diaphragm over a hole in a rigid wall of the fluid flow chamber, providing a second chamber on the other side of the diaphragm, and sensing the pressure in the second chamber.

An extracorporeal blood processing system is disclosed which includes a variety of novel components and which may be operated in accordance with a variety of novel methodologies. For instance, the system includes a graphical operator interface which directs the operator through various aspects of the apheresis procedure. Moreover, the system also includes a variety of features relating to loading a blood processing vessel into a blood processing channel and removing the same after completion of the procedure. Furthermore, the system also includes a variety of features relating to utilizing a blood priming of at least portions of the apheresis system in preparation for the procedure. In addition, the system includes a variety of features enhancing the performance of the apheresis system, including the interrelationship between the blood processing vessel and the blood processing vessel and the utilization of high packing factors for the procedure.

A method of making a peelable tube assembly (76,80,84,88) having a plurality of adjacent tube portions (62) joined by intermittent breakable webs (72) of plastic allowing the individual portions (62) to be peeled from the tube assembly, including providing a plurality of plastic tube portions (62) each having a tube wall (66) defining a flow passage (70). The tube portions (62) are aligned adjacent to one another in a die assembly (12) having compression channels (30). Narrow confined flow chambers (32) are defined between adjacent portions (62) of the tube walls (66), and between the ends of the tube walls (66). The tube portions (62) are radially compressed without occluding the flow passage (70). Small compressed portions of the tube walls (66) proximate the flow chambers (32) are heated and plasticized. The plasticized tube walls portions (66) are flowed into the flow chambers (32) between the adjacent tube portions (62) to fuse the adjacent tube portions ( 62) together with intermittent webs (72) joining the tubular portions (62) until the webs (72) are broken when peeling a tubular portion (62) from the tube assembly (76,80,84,88).