Classifying – separating – and assorting solids – Fluid suspension – Liquid
Reexamination Certificate
1999-09-24
2001-08-14
Walsh, Donald P. (Department: 3653)
Classifying, separating, and assorting solids
Fluid suspension
Liquid
C209S132000, C209S155000, C209S172000, C209S172500, C210S600000, C210S739000, C210S767000
Reexamination Certificate
active
06273264
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention concerns a device and a method for separating particles contained in a fluid by means of a separating arrangement, which has at least one feed duct and at least two discharge ducts, said separating arrangement having a measuring device for sensing the separation level and provided with the discharge ducts, a control arrangement connected to the measuring device and comprising at least one respective arrangement for changing the cross section of at least one of the discharge ducts, said respective arrangement being connected to the measuring device.
The device and the method are suitable in particular for the treatment of biological fluids, such as milk or blood for example, being known in the latter case by the term plasmapheresis. This is understood to mean the mechanical separation of solid blood constituents and plasma after blood has been taken, plasmapheresis usually being carried out by means of a separating arrangement having a centrifuge.
2. Description of the Prior Art
There are numerous devices for automated blood donation, so-called haemapheresis, with which the required blood components, such as erthrocytes, thrombocytes, leucocytes, plasma etc., can be specifically collected, all of which devices operate on the centrifugal principle and have not only a considerable space requirement but also a high weight, of the order of magnitude of 20 to 200 kg, and are correspondingly expensive. These cell separators, which are used for removing whole blood, also require an extracorporeal amount of blood of the order of magnitude of 500 ml, it being important not to exceed a maximum throughflow in order to ensure satisfactory functioning of the centrifuge used for the separation.
BRIEF SUMMARY OF THE INVENTION
The object of the invention is to provide a device for separating particles contained in a fluid which is particularly simple in construction, has a high separating efficiency and causes considerably lower production and operating costs, as well as to specify an associated method.
Another object of the invention is to eliminate as many pumps as possible, preferably all but the one feeding pump upstream of the device, and to replace them by proportional valves which have a very short reaction time and are cheap.
On the basis of a device of the type specified more precisely at the beginning, this object is achieved by a device for separating dense particles contained in blood or one or more proteins contained in blood plasma by means of a separating arrangement which has the following components:
one feed duct,
at least two discharge ducts,
a pump for producing a pressure in order to introduce the blood or blood plasma into the separating device,
a measuring device provided with the discharge ducts,
a control arrangement connected to the measuring device, and
a respective arrangement changing the cross section of at least one of the two discharge ducts and connected to the control arrangement.
The respective arrangement may change the cross section of one of the two discharge ducts or of both discharge ducts.
As a measuring device, a device sensing the separation level, such as an optical device can be used.
The device according to the invention, which is suitable for the treatment of a wide range of biological or non-biological fluids and serves in particular for the treatment of blood, allowing thrombocyles and plasma to be collected at the same time, has the advantage of a considerably lower space requirement.
With such a device, most of the pumps are eliminated, especially all pumps within the circuit or on the discharge side, to be replaced by rapid and cheap arrangement, such as valves.
The same object is achieved by a method for separating dense particles contained in blood or one or more proteins contained in blood plasma using a device, which has the following method steps
the whole blood or the plasma is introduced into the separating device through the feed duct at a pressure produced by the pump,
the degree of separation is established by means of the measuring device,
the control arrangement brings about a change in the passage cross section of one or both discharge ducts with the aid of the arrangement changing the cross section of the discharge ducts if the limit between the dense particles and the blood or the proteins of plasma shifts so that it is ensured that the amount of blood or plasma fed in is equal to the sum of the amounts of the constituents emerging from the two discharge lines, and a high degree of separation is thus maintained.
In a first embodiment of the invention, the regulation device is, instead of the previously customary centrifuge, associated with a stationary hollow chamber, into one end of which the fluid is introduced tangentially at a given rate in such a way that the desired separation is brought about by the centrifugal forces occurring on the inside wall of the hollow chamber with the associated laminar flow, so that the dense particles contained in the fluid can be removed at the other end of the hollow chamber through the one discharge duct, while the fluid itself, in particular plasma, is removed through the other discharge duct. The laminar flow of the blood produces a better separation and less damage to the dense blood cells than in the case of separation by means of a centrifuge, provided that a minimum throughflow and a minimum tangential rate are maintained.
The dimensions of the hollow chamber, which in particular is cylindrical, of the order of magnitude of about 10 mm in diameter and 10 mm in length, require little constructional expenditure and allow a drastic reduction in production costs.
In a second embodiment of the invention, the regulation device is associated with other type of separating devices, such as those described in my co-pending European Patent Applications No. EP 99810294.1 and EP 99810295.8, contents of which are incorporated herein by way of reference.
REFERENCES:
patent: 2967618 (1961-01-01), Vane
patent: 4170555 (1979-10-01), Vicard
patent: 5961841 (1999-10-01), Bowers
patent: 19 45 922 (1971-04-01), None
patent: 2 646 104 (1990-10-01), None
patent: 2 293 993 (1996-04-01), None
patent: WO 93 08892 (1993-05-01), None
Beauchaine Mark J.
Henderson & Sturm LLP
Walsh Donald P.
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