GB2174149A - Apparatus for transfer of liquid from a flexible container - Google Patents

Abstract

The apparatus comprises a plurality of devices 12 for transferring separated blood serum from a flexible container 15 through a tube 17 to a further container 16. The container 15 is compressed by a pivotable plate 32 as the devices are advanced stepwise by an indexing table 10. At a predetermined stepwise position, after transfer of serum has been completed, the tube 17 of each device 12 encounters a combined sealing and cutting device 13 which sequentially compresses the walls of the tube 17, heats the compressed zone to fuse contacting areas of the tube 17 together and cuts through the fused area. <IMAGE>

Description

SPECIFICATION Apparatus for transfer of liquid from a flexible container This invention relates to apparatus for transfer of liquid from a flexible container, and in particular to an apparatus for removing centrifugally separated plasma from bags which have earlier been used to store donated whole blood. It is desirable that as much as possible of the centrifugally separated plasma shall be removed from the bag, while at the same time preventing transfer of red blood cells. The transfer operation is at present performed by a manually operated press, and control of the operation to avoid transfer of red blood cells is generally dependent on the skill of an operator. Demand for plasma is increasing and its centrifugation and separation is a major factor affecting the required increase in supply.

It is one object of the invention to provide an apparatus in which the speed of transfer and repetition rate of plasma separation is substantially increased.

According to the invention there is provided an apparatus for transfer of liquid from a first, flexible container which is connected by a passage to a second container, the apparatus comprising an indexable support having a plurality of equiangularly spaced transfer devices thereon, each said transfer device including means for locating said first container, means, responsive to indexing movement of the transfer device from a location at which a first container can be inserted therein, for compressing said first container, and means responsive to change in the characteristics of liquid flowing in said passage for arresting said flow.

In a preferred embodiment said passage includes at least a translucent portion and said means for arresting flow comprises means for detecting change in transmission of light through said portion and for deforming said passage to arrest flow.

In further preferred embodiment each said transfer device includes means for locating the second container and said apparatus includes means located at an indexing position to which each said transfer device is moved after operation of said flow arresting means, for sealing and cutting said passage.

An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings in which: Figure 1 is a diagrammatic plan view of the apparatus, Figure 2 is a pictorial view of a transfer device forming part of Figure 1, Figure 3 is a diagram of an actuator for the transfer device of Figure 2, Figure 4 is a diagram of flow arresting means forming part of Figure 2, Figure 5 is a part sectioned pictorial view of a sealing and cutting device forming part of Figure 1 and Figure 6 is a diagram of an actuator arrangement for the device of Figure 5.

The drawings are intended to be read in conjunction and corresponding parts have identical reference numerals.

As shown in Figure 1 an indexing table 10 is mounted for stepwise rotation about an axis 11. The table 10 is of a commercially available type and can be controlled by an operator to advance one step at a time. Mounted on the table 10 are twelve equiangularly spaced transfer devices 12. Each of the devices 12 is adapted to receive and locate a first flexible plastics bag containing plasma, platelets and red blood cells and a second plastics bag, connected to the first bag by a translucent or flexible plastics tube, for receiving plasma. The table 10 rotates clockwise as viewed in Figure 1 and the pairs of bags are loaded onto the apparatus at an indexing station indicated at Land are unloaded therefrom at the same station or at a station indicated at U.During stepwise movement of each transfer device 12 from the location L the first bags are squeezed to transfer serum therefrom to the secong bags, and this operation is completed at least by the time that each of the devices 12 reaches a location indicated at S. A sealing and cutting device 13, described in more detail with reference to Figures 5 and 6, seals and cuts the connecting tube between each pair of bags.

In Figure 2 the first and second bags 15, 16 and their interconnecting tube 17 are shown in position in a transfer device 12. The connection of the tube 17 to the bag 15 is by way of a portion 18 which includes a breakable closure. This closure can be opened to allow plasma to pass into the tube 17 by flexing the portion 18. The bags 15, 16 and tube 17 are initially supplied interconnected and a donor's blood enters the bag 15 through a tube 19 which is subsequently sealed. The bag 15 and its contents, with the bag 16 and tube 17 folded and attached thereto, are centrifuged to separate the platelets and red cells from the plasma. Plasma and platelets, if required, are then transferred to the bag 16, for which purpose the bags 15, 16 are inserted into the transfer device 12 as shown.The tube 17 is led over a semi-circular guide 20 whose height is adjustable, and also passes through a detecting and clamping device 21, to be described in detail.

The device 12 comprises side plates 30,31 in which a transparent compression plate 32 is pivotally mounted. The plate 32 is secured to a crank arm 33 and an actuator 34 (shown in Figure 3) is mounted under the table 10 to pivot the plate 32 and squeeze the contents of the bag 15 through the tube 17. The bag 16 is located externally of the plate 31 and lies between that plate and a further plate 35. The plate 35 is biased away from the plate 31 by springs 36 which act on spacers 37. A toggle mechanism 38 mounted on the plate 31 can be operated to bring a pressure pad 39 into contact with the plate 35 and urge the latter against the springs 36 until the spacers 37 engage the plate 31. In this condition the amount of plasma which can be received by the bag 16 is limited by the spacing between the plates 31, 35.For unloading the toggle mechanism 38 is released and the bag 16 is then readily removable.

As shown in Figure 3 the actuator 34 is a double acting pneumatic piston and cylinder unit mounted on the underside of the table 10. A pneumatic pressure line P and return line R are connected to the actuator 34 through a conventional spring loaded change-over valve 40 which is operated by a cam form 41 on a stationary mounting forthetable 10.

The cam form 41 is such as to move the valve 40 to its operated state (shown) after the transfer device 12 has left the location L (Figure 1). Conveniently the valve 40 includes a flow restriction 42 so that operation of the actuator 34 to cause the bag 15 to be squeezed takes place at a predetermined controlled rate. The cam form 41 may be such as to maintain the actuator 34 in its operated state until after the transfer device 12 has passed through the sealing and cutting device 13 (Figure 1).

The detection and clamping device 21 ensures that flow through the tube 7 is arrested before the red blood cells can enter the bag 16. For this purpose two identical detector devices 45,46 and two identical clamping devices 47,48 are provided. As shown in Figure 2 the clamping and detector devices are covered by flaps 49 which are shown in that figure as partly cut away. As shown in Figure 4 each of the detector devices 45,46 comprises a cold light source 51 for emitting green light. A light detector 52 is responsive to light from the source 51 to provide a signal on a line 53 to a control circuit 54. The arrangement is such that the detector 52 is particularly sensitive to the presence of red blood cells in the tube 17, so that a fall in the magnitude of the signal on line 53 is indicative of the presence of those cells.Each of the clamping devices 47,48 comprises a blade 56 which can be urged towards an anvil portion 57 by a pneumatic piston 58, against a biasing spring 59. A pneumatic supply pressure P and a return pressure R are selectively applied to the piston 58 through a spring-loaded electromagnetically operated change over valve 60. The arrangement is such that the presence of red blood cells in the tube 17 at the detector device 45 causes the clamping device47 nearertothe bag 15to operate. If the detector device 45 or clamping device 47 fail to operate the devices 46,48 operate to arrest serum flow.Since red blood cells will then remain within the tube 17, at at least one of the detector devices, a further light detector 61 is provided responsive to lightfrom a source 62 mounted beneath a small aperture 63 in a relatively fixed part 64 of the apparatus, so that the circuit 54 is reset as the detector 61 is indexed past the aperture 63.

Conveniently this reset operation takes place at indexing location R (Figure 1).

The view of the sealing and cutting device 13 shown in Figure 5 corresponds to the view in Figure 1 with the latter rotated about the longer axis of the device. The device 13 comprises a commercially available RF generator 70 having a power input 71.

RF outputfrom the generator 70 passes through a guide 72 to the aligned hollow stem 73 of a double acting piston 74. The piston 74 is slidable in a block 75 provided with a slot 76 which is positioned to receive the radially outer straight runs of the tubes 17 (Figure 2) as the transfer devices 12 successively reach the index position C. The piston stem 73 terminates in a head 77 which is elongated in a direction which is transverse to the axes of the stem 73 and the tube 17. Secured within the block 75 so as to oppose the head 77 is a terminal 78 of the generator 70. A single acting piston 79 is slidable in the block 75 and carries a blade 80 which passes through a slot 81 in the terminal 78. The head 77 has a slot 82 which is aligned with the slot 81 and can receive the blade 80.The piston 79 is spring biased so that in the absence of a pneumatic pressure the blade 80 is withdrawn within the slot 81.

As shown in Figure 6 pneumatic supply and return pressures P, R are applied to the piston 74 through a change-over valve 90 which is electro-mag netical ly operable against a spring. An electrical signal for operating the valve 90 is supplied on a line 91 from a control circuit 92. The piston 79 is operable against a spring 93 by pneumatic pressure supplied through a change-over valve 94 which is also electromagnetically operable against a spring by a signal on a line 95 from the control circuit 92. The control circuit 92 is responsive to a signal from a detector device 96 when a transfer device 12 is stationary in the location C (Figure 1) and hence a tube 17 is between the head 77 and electrode 78. In this position the tube is heated by RF from the generator 70 and the valve 90 is energised to compress the tube between the head 77 and terminal 78. After an appropriate interval the control circuit 92 energises the valve 94 and the blade 80 cuts the tube 17 and enters the slot 82. At the end of the foregoing sequence the control circuit deenergises the valve 90,94.

Subsequent indexing steps of the table 10 bring each transfer device, carrying separated and sealed bags 15, from location Cto the unloading location U (Figure 1).

Claims (13)

1. Apparatus for transfer of a liquid from a first flexible container which is connected by a passage to a second container, said apparatus comprising a transfer device for successively compressing each of a plurality of said first containers to discharge said liquid into said passage characterised in that there is provided a device operable at a predetermined interval after operation of said transfer device, for sealing and cutting each said passage.

2. An apparatus as claimed in Claim 1 in which said device for sealing said passage comprises means for compressing a zone of said passage so as to prevent liquid flow therethrough, and means for heating said compressed zone to fuse surfaces of said passage which are in mutual contact.

3. An apparatus as claimed in Claim 2 in which said means for heating said compressed zone comprises a radio frequency generator having two terminals and means for locating said passages between said terminals.

4. An apparatus as claimed in Claim 3 in which said means for compressing said zone of said passage comprises an actuator arrangement responsive to lapse of said interval for causing relative movement between said terminals to compress said passage.

5. An apparatus as claimed in Claim 4 in which said means for cutting each said passage comprises a blade mounted for movement relative to one of said terminals and being engageable with the other of said terminals and a further actuator operable at a predetermined time after relative movement between said terminals for moving said blade into engagement with the other of said terminals.

6. An apparatus as claimed in Claim 5 in which said actuator arrangement acts on said other of the terminals and said blade is mounted for sliding movement in said one terminal.

7. An apparatus as claimed in Claim 6 in which said other terminal is provided with a slot for receiving said blade.

8. An apparatus as claimed in any of Claims 4to 7 in which said actuator arrangement and said further actuator are fluid powered.

9. An apparatus as claimed in any of Claims 1 to 8 which comprises means for transporting, compressing, sealing and cutting a plurality of said first containers and of said passage sequentially.

10. An apparatus as claimed in Claim 9 in which said means for transporting said first containers comprises an indexable support having a plurality of equi-angularly spaced transfer devices thereon, each said transfer device comprising means for receiving and locating a first container and a device responsive to movement of its transfer device from a location in which said first container can be inserted, for compressing said first container.

11. An apparatus as claimed in Claim 10 in which each said transfer device includes means responsive to a change in the characteristics of liquid flowing in said passage, for arresting said flow.

12. An apparatus as claimed in Claim 11 in which said means for arresting flow comprises a detecting device responsive to transmission of light through a portion of said passage and an element responsive to a signal from said detecting device for deforming said passage to arrest flow.

13. An apparatus for transfer of liquid from a first, flexible container to a second container, substantially as hereinbefore described with reference to the accompanying drawings.