Autotransfusion apparatus

Claim 2

An autotransfusion apparatus shaving two chambers with simplified control of the cycling of the flow of fluid between the chambers and safeguards to prevent cross-flow between the chambers and passage of air to a patient from an empty chamber, comprising, in combination, first and second fluid chambers each having a fluid inlet, a fluid outlet, a line connection to a source of vacuum, and a vent connection to atmospheric pressure; the vent being provided with a flow-resistant filter having a pore size such that bacteria cannot pass through it, and restricting flow into the chamber from the atmosphere so that a vacuum can be drawn on the chamber without closing the vent, while allowing the chamber to reach equilibrium with atmospheric pressure when vacuum is not applied; the filter not being wetted by the liquid in the system so as not to accept blood or other medicament in its pores and thus block the passage of air therethrough; a check valve at the fluid inlet restricting flow through the inlet line to flow towards the chamber at fluid pressures within the chamber below the pressure in the inlet line; and means for alternately opening and closing the vacuum line to each chamber, so that when the vacuum line is open to the first chamber it is closed to the second; and when the vacuum line is closed to the first chamber, it is open to the second.

Claim 3

An autotransfusion apparatus according to claim 1, having a check valve at the fluid outlet, restricting fluid flow through the outlet except at a higher upstream fluid pressure.

Claim 4

An autotransfusion apparatus according to claim 1, having a vent in each chamber that is open to the atmosphere at all times.

Claim 5

An autotransfusion apparatus according to claim 1, in which the flow-resistant filter has a pore size of less than 3 microns and an open area less than 5%.

Claim 6

An autotransfusion apparatus according to claim 1, having two chambers with simplified control of the foaming of fluid entering the chambers in which the fluid inlet directs flow to impinge upon a wall of the chamber; so as to flow in a thin film down the wall, and afford an extended surface area for defoaming.

Claim 7

An autotransfusion apparatus according to claim 5, having a deflector at the inlet end of the fluid inlet.

Claim 8

An autotransfusion apparatus according to claim 6 in which the deflector is a turned end of the inlet tube.

Claim 9

An autotransfusion apparatus according to claim 5 in which the inlet tube outlet is directed towards a wall of the chamber.

Claim 10

An autotransfusion apparatus according to claim 1, having two chambers with simplified prevention of the passage of air to a patient from an empty chamber, comprising, a float valve in each chamber, moving on and with the fluid level in the chamber, and a valve seat at the bottom of the chamber, so that when the fluid level sinks to the level of the valve seat, the float valve sinks into sealing engagement with the valve seat, and closes off the fluid outlet from the chamber, preventing air from entering the outlet.

Claim 11

An autotransfusion apparatus according to claim 9 in which the float valve is a disc, which is free in the chamber, and is light enough to float on the surface of the fluid, and is provided with a resilient peripheral ring which seals against a valve seat on its lower surface, and an annular valve seat surrounding the outlet, against which the ring seals.

Claim 12

An autotransfusion apparatus according to claim 9 in which, at the outlet from each chamber, below the valve seat, a coarse filter is provided, to prevent obstruction of the outlet line.

Claim 13

An autotransfusion apparatus according to claim 11 in which the coarse filter Is a nonwoven plastic fiber cloth.

Claim 14

An autotransfusion apparatus having two chambers with simplified control of the cycling of the flow of fluid between the chambers and safeguards to prevent cross-flow between the chambers and passage of air to a patient from an empty chamber, comprising, in combination, first and second fluid chambers each having a fluid inlet, a fluid outlet, a line connection to a source of vacuum, and a vent connection to atmospheric pressure provided with a flow-resistant filter having a pore size such that bacteria cannot pass through it; a check valve at the fluid inlet in each chamber, restricting flow through the inlet line to flow towards the chamber at fluid pressures within the chamber below the pressure in the inlet line; the fluid inlet directing inlet flow to impringe upon a wall of the chamber, so as to flow in a thin film down the wall, and afford an extended surface area for defoaming; a float valve in each chamber, moving on and with the fluid level in the chamber, and a valve seat at the bottom of the chamber, so that when the fluid level sinks to the level of the valve seat, the float valve sinks into sealing engagement with the valve seat, and closes off the fluid outlet from the chamber, preventing air from entering the outlet; and means for alternately opening and closing the vacuum line to each chamber, in synchronization, so that when the vacuum line is open to the first chamber it is closed to the second; and when the vacuum line is closed to the first chamber, it is open to the second.

Claim 15

An autotransfusion apparatus having two chambers with simplified control of the cycling of the flow of fluid between the chambers and safeguards to prevent cross-flow between the chambers and passage of air to a patient from an empty chamber, comprising, in combination, first and second fluid chambers each having a fluid inlet, a fluid outlet, a line connection to a source of vacuum, and a vent connection to atmospheric pressure provided with a flow-resistant filter having a pore size such that bacteria cannot pass through it; a check valve at the fluid inlet in each chamber, restricting flow through the inlet line to flow towards the chamber at fluid pressures within the chamber below the pressure in the inlet line; the fluid inlet directing inlet flow to impringe upon a wall of the chamber, so as to flow in a thin film down the wall, and afford an extended surface area for defoaming; a float valve in each chamber, moving on and with the fluid level in the chamber, and a valve seat at the bottom of the chamber, so that when the fluid level sinks to the level of the valve seat, the float valve sinks into sealing engagement with the valve seat, and closes off the fluid outlet from the chamber, preventing air from entering the outlet; and means for alternately opening and closing the vacuum line to each chamber, in synchronization, so that when the vacuum line is open to the first chamber it is closed to the second; and when the vacuum line is closed to the first chamber, it is open to the second.

Claim 16

An autotransfusion apparatus according to claim 13, in which each chamber has a check valve at the fluid outlet, restricting fluid flow through the outlet except at a higher upstream fluid pressure.

Claim 17

An autotransfusion apparatus according to claim 13, in which each chamber and float valve are shaped so as to guide the float valve into sealing engagement with the valve seat.