Pump for low flow rates
First Claim
1. Pump for low flow rates comprisinga channel which is at least partially filled with a transport liquid (3) a membrane (4, 12) at one opening of the channel that can be wetted by the transport liquid, a gas space having an essentially constant vapour pressure of evaporated transport liquid located at the side of the membrane opposite to the transport liquid, wherein a continuous and constant loss of vapour results in a vapour pressure below a saturation vapour pressure, thus leading to an essentialy constant flow rate through the membrane.
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Accused Products
Abstract
The present invention concerns a pump for flow rates from about 1 to 1000 nl/min in which liquid transport takes place by evaporation of a transport liquid through a wettable membrane. The pumps according to the invention are particularly suitable for applications in the field of medical diagnostics such as microdialysis or ultrafiltration.
35 Citations
43 Claims
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1. Pump for low flow rates comprising
a channel which is at least partially filled with a transport liquid (3) a membrane (4, 12) at one opening of the channel that can be wetted by the transport liquid, a gas space having an essentially constant vapour pressure of evaporated transport liquid located at the side of the membrane opposite to the transport liquid, wherein a continuous and constant loss of vapour results in a vapour pressure below a saturation vapour pressure, thus leading to an essentialy constant flow rate through the membrane.
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11. Pump for low flow rates comprising
a channel which is at least partially filled with a transtport liquid (3) a membrane (4, 12) at one opening of the channel that can be wetted by the transport liquid, and a space having an essentially constant vapour pressure of the transport liquid located at the side of the membrane opposite to the transport liquid, in which the space contains a sorbent (6, 15) which sorbs evaporated transport liquid, wherein the membrane has a hydrophilic region facing the transport liquid and a hydrophobic region which faces the sorbent.
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13. Pump for low flow rates comprising
a channel which is at least partially filled with a transport liquid (3) a membrane (4, 12) at one opening of the channel that can be wetted by the transport liquid, a space having an essentially constant vapour pressure of the transport liquid located at the side of the membrane opposite to the transport liquid, and at least one non-wettable membrane (5) which is located on a side of the wettable membrane facing away from the transport liquid.
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14. Pump for low flow rates comprising
a channel which is at least partially filled with a transport liquid (3) a membrane (4, 12) at one opening of the channel that can be wetted by the transport liquid, a space having an essentially constant vapour pressure of the transport liquid located at the side of the membrane opposite to the transport liquid, wherein the channel contains a working liquid that is segmented from the transport liquid.
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15. Pump for low flow rates comprising
a channel which is at least partially filled with a transport liquid (3) a membrane (4, 12) at one opening of the channel that channel wetted by the transport liquid, a space having an essentially constant vapour pressure of the transport liquid located at the side of the membrane opposite to the transport liquid, wherein the membrane is formed by an array of capillary channels.
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21. Microdialysis system comprising
a pump having a channel which is at least partially filled with a transport liquid (3) a membrane which (4, 12) at one opening of the channel that can be wetted by the transport liquid, a space having an essentially constant vapour pressure of the transport liquid located at the side of the membrane opposite to the transport liquid, and a microdialysis membrane, wherein the transport liquid or a working liquid is transported through the microdialysis membrane by the pump.
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23. Ultrafiltration device comprising
a pump having a channel which is at least partially filled with a transport liquid (3) a membrane which (4, 12) at one opening the channel that can be wetted by the transport liquid, a space having an essentially constant vapour pressure of the transport liquid located at the side of the membrane opposite to the transport liquid, an ultrafiltration membrane through which a body fluid is drawn into the channel, and a sensor located downstream of the ultrafiltration membrane for the detection of one or several analytes in the body fluid.
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24. System for pumping a working liquid at a low flow rate, wherein at least one dilution reservoir (22) containing a liquid which is essentially free of substances that cannot evaporate at the membrane is located between a fluid system in which the working liquid is located and a pump including
a channel which is at least partially filled with a transport liquid (3) a membrane (4, 12) at one opening of the channel that can be wetted by the transport liquid, a space having an essentially constant vapour pressure of the transport liquid located at the side of the membrane opposite to the transport liquid.
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26. A pump comprising:
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a housing defining a gas space and including a channel, the channel being at least partially filled with a transport liquid, and a membrane positioned in the housing, the membrane including a first side facing toward the liquid and a second side facing the gas space, wherein the gas space has an essentially constant vapour pressure of evaporated transport liquid, wherein a continuous and constant loss of vapour results in a vapour pressure below a saturation vapour pressure, thus leading to an essentially constant flow rate through the membrane. - View Dependent Claims (27, 28, 29, 30, 31, 32)
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33. A pump comprising:
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a housing defining a space and including a channel, the channel being at least partially filled with a transport liquid, and a membrane positioned in the housing, the membrane including a first side facing toward the liquid and a second side facing the space, wherein the space has an essentially constant vapour pressure of the transport liquid, wherein the membrane has a hydrophilic region facing the transport liquid and a hydrophobic region facing the space.
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34. A pump comprising:
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a housing defining a space and including a channel, the channel being at least partially filled with a transport liquid, and a membrane positioned in the housing, the membrane including a first side facing toward the liquid and a second side facing the space, wherein the space has an essentially constant vapour pressure of the transport liquid, and at least one non-wettable membrane positioned in the space.
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35. A pump comprising:
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a housing defining a space and including a channel, the channel being at least partially filled with a transport liquid, and a membrane positioned in the housing, the membrane including a first side facing toward the liquid and a second side facing the space, wherein the space has an essentially constant vapour pressure of the transport liquid, and a working liquid positioned in the channel that is segmented from the transport liquid.
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36. A pump comprising:
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a housing defining a space and including a channel, the channel being at least partially filled with a transport liquid, and a membrane positioned in the housing, the membrane including a first side facing toward the liquid and a second side facing the space, wherein the space has an essentially constant vapour pressure of the transport liquid, the membrane is formed to include capillary channels. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43)
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Specification