Membrane plasmapheresis apparatus and process which utilize a flexible wall to variably restrict the flow of plasma filtrate and thereby stabilize transmembrane pressure

Claim 2

A membrane plasmapheresis process which comprises the steps of introducing a flow of whole blood subject to a predetermined inlet pressure into a fluid path defined by membrane fluid path means, across a membrane, the membrane having a pore size suited for filtering plasma from the whole blood, conducting plasma-poor blood from the defined membrane fluid path through a plasma-poor blood fluid path defined by plasma-poor blood fluid path means, subject to a plasma-poor blood pressure which is subject to random variations, conducting plasma filtrate from the defined membrane fluid path through a filtrate fluid path defined by filtrate-fluid path means, subject to a plasma filtrate pressure which is initially less than the plasma-poor blood pressure, diverting the plasma filtrate in the defined filtrate fluid path through an intermediate fluid pathway defined by intermediate fluid pathway means, the defined intermediate fluid pathway having a filtrate inlet defined by filtrate inlet means, said filtrate inlet means further defining a filtrate inlet axis such that the plasma filtrate enters the defined intermediate fluid pathway from the defined filtrate fluid path through the defined filtrate inlet generally along the defined axis thereof, and a filtrate outlet defined by filtrate outlet means, through which the plasma filtrate exits the defined intermediate fluid pathway and returns to the defined filtrate fluid path, and variably restricting flow of plasma filtrate through the defined filtrate inlet by placing between the defined plasma-poor blood fluid path and the defined intermediate fluid pathway a flexible wall means generally oppositely spaced from and in facing relationship to the defined filtrate inlet, the flexible wall means moving in response to a pressure differential between the plasma-poor blood and the plasma filtrate, toward and away from the defined filtrate inlet in a path defined generally along the defined axis of the defined filtrate inlet to establish and thereafter maintain substantial equilibrium between the pressure of the plasma filtrate and the pressure of the plasma-poor blood, despite random variations in the plasma-poor blood pressure.

Claim 3

A process according to claim 1 and further including the step of maintaining an uninterrupted flow of plasma filtrate through the defined filtrate inlet while the flow is being variably restricted.

Claim 4

A process according to claim 1 or 2 and further including the step of maintaining a laminar flow of plasma-poor blood along one side of the flexible wall means.

Claim 5

A process according to claim 3 and further including the step of maintaining an uninterrupted flow of plasma-poor blood along one side of the flexible wall means.

Claim 6

A membrane phasmapheresis apparatus comprising: membrane means for filtering plasma from whole blood, means for forming a fluid path across said membrane means, means communicating with said membrane means for communication with a source of whole blood for introducing the whole blood subject to a predetermined inlet pressure into the membrane fluid path defined by said membrane fluid path forming means, to filter the plasma from the whole blood, means communicating with said membrane means for conducting plasma-poor blood from the defined membrane fluid path subject to a plasma-poor blood pressure which is subject to random variations, means communicating with said membrane means for conducting plasma filtrate from the defined membrane fluid path subject to a plasma filtrate pressure which is initially less than the plasma-poor blood pressure, means for forming in said plasma filtrate conduction means an intermediate fluid pathway, a filtrate inlet to the defined intermediate fluid pathway and a filtrate inlet axis to the defined filtrate inlet such that the plasma filtrate is conducted from said plasma filtrate conduction means into the defined intermeidate fluid pathway through the defined filtrate inlet generally along the defined axis thereof, and means for forming a filtrate outlet, through which the plasma filtrate is conducted out of the defined intermediate fluid pathway and back to said plasma filtrate conduction means, and means forming between a portion of said plasma-poor blood conduction means and the defined intermediate fluid pathway a flexible wall generally oppositely spaced from and in facing relationship to the defined filtrate inlet, said flexible wall means being operatively movable in response to the pressure differential between the plasma-poor blood and the plasma filtrate, toward and away from the defined filtrate inlet in a path defined generally along the defined axis of the defined filtrate inlet for variably restricting the conduction of plasma filtrate through the defined filtrate inlet to establish and thereafter maintain substantial equilibrium between the pressure of the plasma filtrate and the pressure of the plasma-poor blood, despite random variations in the plasma-poor blood pressure.

Claim 7

A membrane phasmapheresis apparatus comprising: membrane means for filtering plasma from whole blood, means for forming a fluid path across said membrane means, means communicating with said membrane means for communication with a source of whole blood for introducing the whole blood subject to a predetermined inlet pressure into the membrane fluid path defined by said membrane fluid path forming means, to filter the plasma from the whole blood, means communicating with said membrane means for conducting plasma-poor blood from the defined membrane fluid path subject to a plasma-poor blood pressure which is subject to random variations, means communicating with said membrane means for conducting plasma filtrate from the defined membrane fluid path subject to a plasma filtrate pressure which is initially less than the plasma-poor blood pressure, means for forming in said plasma filtrate conduction means an intermediate fluid pathway, a filtrate inlet to the defined intermediate fluid pathway and a filtrate inlet axis to the defined filtrate inlet such that the plasma filtrate is conducted from said plasma filtrate conduction means into the defined intermeidate fluid pathway through the defined filtrate inlet generally along the defined axis thereof, and means for forming a filtrate outlet, through which the plasma filtrate is conducted out of the defined intermediate fluid pathway and back to said plasma filtrate conduction means, and means forming between a portion of said plasma-poor blood conduction means and the defined intermediate fluid pathway a flexible wall generally oppositely spaced from and in facing relationship to the defined filtrate inlet, said flexible wall means being operatively movable in response to the pressure differential between the plasma-poor blood and the plasma filtrate, toward and away from the defined filtrate inlet in a path defined generally along the defined axis of the defined filtrate inlet for variably restricting the conduction of plasma filtrate through the defined filtrate inlet to establish and thereafter maintain substantial equilibrium between the pressure of the plasma filtrate and the pressure of the plasma-poor blood, despite random variations in the plasma-poor blood pressure.

Claim 8

A membrane plasmapheresis apparatus according to claim 5 and further including means for maintaining an uninterrupted flow of plasma filtrate through the defined filtrate inlet into the defined intermediate fluid pathway during movement of said flexible wall means.

Claim 9

A membrane plasmapheresis apparatus according to claim 5 or 6 and further including means for maintaining a laminar flow of plasma-poor blood along one side of said flexible wall means.

Claim 10

A membrane plasmapheresis apparatus according to claim 7 and further including means for maintaining an uninterrupted flow of plasma-poor blood along one side of said flexible wall means.

Claim 11

The process according to claim 1, including placing the flexible wall means such that it has an initial position generally perpendicular to the defined axis of the defined filtrate inlet.

Claim 12

A membrane plasmapheresis process which comprises the steps of introducing a flow of whole blood subject to a predetermined inlet pressure into a fluid path defined by membrane fluid path means, across a membrane, the membrane having a pore size suited for filtering plasma from the whole blood, conducting plasma-poor blood from the defined membrane fluid path through a plasma-poor blood fluid path defined by plasma-poor blood fluid path means, subject to a plasma-poor blood pressure which is subject to random variations, conducting plasma filtrate from the defined membrane fluid path through a filtrate fluid path defined by filtrate-fluid path means, subject to a plasma filtrate pressure which is initially less than the plasma-poor blood pressure, diverting the plasma filtrate in the defined filtrate fluid path through an intermediate fluid pathway defined by intermediate fluid pathway means, the defined intermediate fluid pathway having a filtrate inlet defined by filtrate inlet means, said filtrate inlet means further defining a filtrate inlet axis, such that the plasma filtrate enters the defined intermediate fluid pathway from the defined filtrate fluid path through the defined filtrate inlet generally the defined axis thereof, and a filtrate outlet defined by filtrate outlet means, through which the plasma filtrate exits the defined intermediate fluid pathway and returns to the defined filtrate fluid path, and variably restricting flow of plasma filtrate through the defined filtrate inlet by placing between the defined plasma-poor blood fluid path and the defined intermediate fluid pathway a flexible wall means such that the wall means has an initial position generally perpendicular to the defined axis of the defined filtrate inlet, the flexible wall means moving in response to a pressure differential between the plasma-poor blood and the plasma filtrate, toward and away from the defined filtrate inlet in a path defined generally along the defined axis of the devined filtrate inlet to establish and thereafter maintain substantial equilibrium between the pressure of the plasma filtrate and the pressure of the plasma-poor blood, despite random variations in the plasma-poor blood pressure.

Claim 13

A membrane plasmapheresis process which comprises the steps of introducing a flow of whole blood subject to a predetermined inlet pressure into a fluid path defined by membrane fluid path means, across a membrane, the membrane having a pore size suited for filtering plasma from the whole blood, conducting plasma-poor blood from the defined membrane fluid path through a plasma-poor blood fluid path defined by plasma-poor blood fluid path means, subject to a plasma-poor blood pressure which is subject to random variations, conducting plasma filtrate from the defined membrane fluid path through a filtrate fluid path defined by filtrate-fluid path means, subject to a plasma filtrate pressure which is initially less than the plasma-poor blood pressure, diverting the plasma filtrate in the defined filtrate fluid path through an intermediate fluid pathway defined by intermediate fluid pathway means, the defined intermediate fluid pathway having a filtrate inlet defined by filtrate inlet means, said filtrate inlet means further defining a filtrate inlet axis, such that the plasma filtrate enters the defined intermediate fluid pathway from the defined filtrate fluid path through the defined filtrate inlet generally the defined axis thereof, and a filtrate outlet defined by filtrate outlet means, through which the plasma filtrate exits the defined intermediate fluid pathway and returns to the defined filtrate fluid path, and variably restricting flow of plasma filtrate through the defined filtrate inlet by placing between the defined plasma-poor blood fluid path and the defined intermediate fluid pathway a flexible wall means such that the wall means has an initial position generally perpendicular to the defined axis of the defined filtrate inlet, the flexible wall means moving in response to a pressure differential between the plasma-poor blood and the plasma filtrate, toward and away from the defined filtrate inlet in a path defined generally along the defined axis of the devined filtrate inlet to establish and thereafter maintain substantial equilibrium between the pressure of the plasma filtrate and the pressure of the plasma-poor blood, despite random variations in the plasma-poor blood pressure.

Claim 14

The process according to claim 10, including placing the flexible wall means generally oppositely spaced from and in facing relationship to the defined filtrate inlet.

Claim 15

The process accordiing to claims 1 or 10, wherein the flexible wall means includes a mid portion, further including aligning the defined filtrate inlet axis with the mid portion of the flexible wall means.

Claim 16

A membrane plasmapheresis process which comprises the steps of introducing a flow of whole blood subject to a predetermined inlet pressure into a fluid path defined by membrane fluid path means, across a membrane, the membrane having a pore size suited for filtering plasma from the whole blood, conducting plasma-poor blood from the defined membrane fluid path through a plasma-poor blood fluid path defined by plasma-poor blood fluid path means, subject to a plasma-poor blood pressure which is subject to random variations, conducting plasma filtrate from the defined membrane fluid path through a filtrate fluid path defined by filtrate-fluid path means, subject to a plasma filtrate pressure which is initially less than the plasma-poor blood pressure, diverting the plasma filtrate in the defined filtrate fluid path through an intermediate fluid pathway defined by intermediate fluid pathway means, the defined intermeidate fluid pathway having a filtrate inlet defined by filtrate inlet means, through which the plasma filtrate enters the defined intermediate fluid pathway from the defined filtrate fluid path, and a filtrate outlet defined by filtrate outlet means, through which the plasma filtrate exits the defined intermediate fluid pathway and returns to the defined filtrate fluid path, and placing between the defined plasma-poor blood fluid path and the defined intermediate fluid pathway a flexible wall means, said flexible wall means moving in response to a pressure differential between the plasma-poor blood and the plasma filtrate to establish and thereafter maintain substantial equilibrium between the pressure of the plasma filtrate and the pressure of the plasma-poor blood, despite random variations in the plasma-poor blood pressure.

Claim 17

A membrane plasmapheresis process which comprises the steps of introducing a flow of whole blood subject to a predetermined inlet pressure into a fluid path defined by membrane fluid path means, across a membrane, the membrane having a pore size suited for filtering plasma from the whole blood, conducting plasma-poor blood from the defined membrane fluid path through a plasma-poor blood fluid path defined by plasma-poor blood fluid path means, subject to a plasma-poor blood pressure which is subject to random variations, conducting plasma filtrate from the defined membrane fluid path through a filtrate fluid path defined by filtrate-fluid path means, subject to a plasma filtrate pressure which is initially less than the plasma-poor blood pressure, diverting the plasma filtrate in the defined filtrate fluid path through an intermediate fluid pathway defined by intermediate fluid pathway means, the defined intermeidate fluid pathway having a filtrate inlet defined by filtrate inlet means, through which the plasma filtrate enters the defined intermediate fluid pathway from the defined filtrate fluid path, and a filtrate outlet defined by filtrate outlet means, through which the plasma filtrate exits the defined intermediate fluid pathway and returns to the defined filtrate fluid path, and placing between the defined plasma-poor blood fluid path and the defined intermediate fluid pathway a flexible wall means, said flexible wall means moving in response to a pressure differential between the plasma-poor blood and the plasma filtrate to establish and thereafter maintain substantial equilibrium between the pressure of the plasma filtrate and the pressure of the plasma-poor blood, despite random variations in the plasma-poor blood pressure.

Claim 18

The process according to claim 13, wherein the flexible wall means includes a mid portion and wherein the defined filtrate inlet has an axis therethrough defined by said filtrate inlet means, further including aligning the defined filtrate inlet axis with the mid portion of the flexible wall means.

Claim 19

The apparatus according to claim 5, further wherein said flexible wall means is disposed in an initial position that is generally perpendicular to the defined axis of the defined filtrate inlet.

Claim 20

A membrane plasmapheresis apparatus comprising: membrane means for filtering plasma from whole blood, means for forming a fluid path across said membrane means, means communicating with said membrane means for communication with a source of whole blood for introducing the whole blood subject to a predetermined inlet pressure into the membrane fluid path defined by said membrane fluid path forming means, to filter the plasma from the whole blood, means communicating with said membrane means for conducting plasma-poor blood from the defined membrane fluid path subject to a plasma-poor blood pressure which is subject to random variations, means communicating with said membrane means for conducting plasma filtrate from the defined membrane fluid path subject to a plasma filtrate pressure which is initially less than the plasma-poor blood pressure, means for forming in said plasma filtrate conduction means an intermediate fluid pathway, a filtrate inlet to the defined intermediate fluid pathway and a filtrate inlet axis to the defined filtrate inlet such that plasma filtrate is conducted from said plasma filtrate conduction means into the defined intermediate fluid pathway through the defined filtrate inlet generally along the defined axis thereof, and means for forming a filtrate outlet, through which the plasma filtrate is conducted out of the defined intermediate fluid pathway and back to said plasma filtrate conduction means, and means forming between a portion of said plasma-poor blood conduction means and the defined intermediate fluid pathway a flexible wall disposed in an initial position generally perpendicular to the defined axis of the defined filtrate inlet, said flexible wall means moving in response to the pressure differential between the plasma-poor blood and the plasma filtrate, toward and away from the defined filtrate inlet in a path defined generally along the defined axis of the defined filtrate inlet for variably restricting the conduction of plasma filtrate through the defined filtrate inlet to establish and thereafter maintain substantial equilibrium between the pressure of the plasma filtrate and the pressure of the plasma-poor blood, despite random variations in the plasma-poor blood pressure.

Claim 21

A membrane plasmapheresis apparatus comprising: membrane means for filtering plasma from whole blood, means for forming a fluid path across said membrane means, means communicating with said membrane means for communication with a source of whole blood for introducing the whole blood subject to a predetermined inlet pressure into the membrane fluid path defined by said membrane fluid path forming means, to filter the plasma from the whole blood, means communicating with said membrane means for conducting plasma-poor blood from the defined membrane fluid path subject to a plasma-poor blood pressure which is subject to random variations, means communicating with said membrane means for conducting plasma filtrate from the defined membrane fluid path subject to a plasma filtrate pressure which is initially less than the plasma-poor blood pressure, means for forming in said plasma filtrate conduction means an intermediate fluid pathway, a filtrate inlet to the defined intermediate fluid pathway and a filtrate inlet axis to the defined filtrate inlet such that plasma filtrate is conducted from said plasma filtrate conduction means into the defined intermediate fluid pathway through the defined filtrate inlet generally along the defined axis thereof, and means for forming a filtrate outlet, through which the plasma filtrate is conducted out of the defined intermediate fluid pathway and back to said plasma filtrate conduction means, and means forming between a portion of said plasma-poor blood conduction means and the defined intermediate fluid pathway a flexible wall disposed in an initial position generally perpendicular to the defined axis of the defined filtrate inlet, said flexible wall means moving in response to the pressure differential between the plasma-poor blood and the plasma filtrate, toward and away from the defined filtrate inlet in a path defined generally along the defined axis of the defined filtrate inlet for variably restricting the conduction of plasma filtrate through the defined filtrate inlet to establish and thereafter maintain substantial equilibrium between the pressure of the plasma filtrate and the pressure of the plasma-poor blood, despite random variations in the plasma-poor blood pressure.

Claim 22

The apparatus according to claim 16, further wherein said flexible wall means is generally oppositely spaced from and in facing relationship to the defined filtrate inlet.

Claim 24

A membrane plasmapheresis apparatus comprising: membrane means for filtering plasma from whole blood, means for forming a fluid path across said membrane means, means communicating with said membrane means for communication with a source of whole blood for introducing the whole blood subject to a predetermined inlet pressure into the membrane fluid path defined by said membrane fluid path forming means, to filter the plasma from the whole blood, means communicating with said membrane means for conducting plasma-poor blood from the defined membrane fluid path subject to a plasma-poor blood pressure which is subject to random variations, means communicating with said membrane means for conducting plasma filtrate from the defined membrane fluid path subject to a plasma filtrate pressure which is initially less than the plasma-poor blood pressure, means for forming in said plasma filtrate conduction means an intermediate fluid pathway, and a filtrate inlet to the defined intermediate fluid pathway, through which the plasma filtrate is conducted from said plasma filtrate conduction means into the defined intermediate fluid pathway, and a filtrate outlet defined by filtrate outlet means, through which the plasma filtrate is conducted out of said defined intermediate fluid pathway and back to said plasma filtrate conduction means, and means forming between a portion of said plasma-poor blood conduction means and said defined intermediate fluid pathway a flexible wall moving in response to the pressure differential between the plasma-poor blood and the plasma filtrate to establish and thereafter maintain substantial equilibrium bewtween the pressure of the plasma filtrate and the pressure of the plasma-poor blood, despite random variations in the plasma-poor blood pressure.

Claim 25

A membrane plasmapheresis apparatus comprising: membrane means for filtering plasma from whole blood, means for forming a fluid path across said membrane means, means communicating with said membrane means for communication with a source of whole blood for introducing the whole blood subject to a predetermined inlet pressure into the membrane fluid path defined by said membrane fluid path forming means, to filter the plasma from the whole blood, means communicating with said membrane means for conducting plasma-poor blood from the defined membrane fluid path subject to a plasma-poor blood pressure which is subject to random variations, means communicating with said membrane means for conducting plasma filtrate from the defined membrane fluid path subject to a plasma filtrate pressure which is initially less than the plasma-poor blood pressure, means for forming in said plasma filtrate conduction means an intermediate fluid pathway, and a filtrate inlet to the defined intermediate fluid pathway, through which the plasma filtrate is conducted from said plasma filtrate conduction means into the defined intermediate fluid pathway, and a filtrate outlet defined by filtrate outlet means, through which the plasma filtrate is conducted out of said defined intermediate fluid pathway and back to said plasma filtrate conduction means, and means forming between a portion of said plasma-poor blood conduction means and said defined intermediate fluid pathway a flexible wall moving in response to the pressure differential between the plasma-poor blood and the plasma filtrate to establish and thereafter maintain substantial equilibrium bewtween the pressure of the plasma filtrate and the pressure of the plasma-poor blood, despite random variations in the plasma-poor blood pressure.

Claim 26

The apparatus according to claim 19, further including a mid portion of said flexible wall means, the defined filtrate inlet having an axis therethrough defined by said filtrate inlet means, said mid portion being aligned with the defined filtrate inlet axis.