Patent GB-1329606-A (GB)
Title: Centrifugal device
IPC: A61M1/02
Filed: 1970-07-30
Abstract: 1329606 Centrifugal separators AGA AB 30 July 1970 [11 Aug 1969] 36838/70 Heading B2P A centrifuge for treating blood comprises a rotor 1-4, Fig. 1, provided with a chamber in which is arranged a compressible container, such as 17, with at least one connecting line, such as 16', attached thereto and adapted to be closed or opened by a valve, such as 16", the volume of the container being influenced by a control device 6. The centrifuge may be used for separating plasma from blood corpuscles and for washing the latter. The interior of the rotor is divided into a lower and an upper chamber by the control device 6 which acts as a pump and consists of a rigid frusto-conical partition wall 7 having an opening 8 therethrough and bounded on opposite sides by rubber diaphragms 9, 10, the diaphragm 10 being reinforced on its underside by a further heavier diaphragm 11 vulcanized to it. The diaphragms are stressed so that they tend to bend downwards. A displacement control liquid 12 is contained between the diaphragms. The control device may be adjusted up or down by rotating it within the rotor, lugs 13 on the wall 7 engaging with the threads of the rotor outer ring 3. Three compresible contamers 14, 15, 16 are mounted in the space between the control device 6 and a bottom disc 2 of the rotor and are connected to flexible tubes 14', 15', 16' which extend through a slot in an annular screen 20, Fig. 2, into the space between the slot and the hub 1 of the rotor and through valves 14", 15", 16" respectively out to a flexible blood container 17 arranged between the control device 6 and a top disc 4 of the rotor which is fixed to a ring 5 threaded with the ring 3. The container 17 is covered by a plastics disc 18 provided with circumferentially spaced chambers 19 on its underside. The valves each comprise an electromagnet 22 which when activated acts on a looped arm 23 to squeeze operation of the centrifuge. To carry out separation and washing, the container 14 is filled with washing liquor and placed with the empty containers 15, 16 in the lower chamber of the rotor. The tubes 14', 15', 16' are connected to the containers and clamped tight by their respective valves 14", 15", 16". The control device 6 with the displacement fluid 12 in its lower part, is then threaded in until practically all the air has been driven out from the lower chamber of the rotor and is locked in this position. The blood container 17 and the disc 18 are inserted and the tubes 14', 15', 16' are connected to the container 17. Finaly the top disc 4 with the ring 5 is screwed down and locked in position. The centrifuge is then started and after the blood corpuscles and plasma have separated in the container 17, the valve 16" is opened, by actuation through the program register, and the heavy diaphragm 10, due to the greater effect of centrifugal force thereon, drives the displacement fluid 12 through the opening 8 thereby causing compression of container 17 and transfer of a corresponding amount of plasma from the container 17 to the container 16. The valve 16" is then shut and the valve 14" opened. The speed of the centrifuge is then reduced to such a value that the stresses of the diaphragms overcome the centrifugal force effect on the diaphragm 10. This causes the displacement fluid to flow back through opening 8 into the lower part of the control device whereby a pumping action takes place transferring washing liquor from container 14 to the container 17. The valve 14" is then closed and the centrifuge speed increased. When full speed has been attained the centrifuge is quickly braked by actuation of an electrically controlled brake through the program register. The liquid in the container 17 continues to rotate. The container 17 being flexible embraces the chambers 19 providing a stirring action so that effective mixing of the blood corpuscles with the washing liquor takes place. The brake is now released and the centrifuge re-started. The valve 15" is then opened and the spent washing liquor transferred to the container 15. The washing process may then be repeated a number of times.