Valveless liquid microswitch
First Claim
1. A liquid microswitch comprising:
- a first, a second and a third microchannel, each having a junction end and a port end, said first, second and third microchannels joined at said junction ends to form a first junction;
a first, a second and a third liquid reservoir, attached to the port ends of said first, second and third microchannels, respectively;
a pressure control means for applying a first driving pressure, P1, a second driving pressure, P2, and a third driving pressure, P3, to said first, second and third liquid reservoirs, respectively, wherein, in a first switching state, P1 is greater than or less than P2, and P3 is approximately equal to PJ, the pressure at said first junction; and
a switching means, connected to said pressure control means, for switching said first, second or third driving pressure to a second switching state, wherein P1 '"'"' is greater than or less than P3 '"'"', and P2 '"'"' is approximately equal to PJ '"'"'.
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Abstract
This invention provides a valveless method and apparatus for high speed switching of liquid flow between intersecting microchannels. Liquid flow is controlled by manipulating external driving pressures. The switch comprises three intersecting microchannels, each having a liquid reservoir at its nonintersecting end for liquid inlet and outlet. It further includes applying a driving pressure to each reservoir switching the driving pressures. The microswitch of this invention operates to establish a liquid flow from a first channel to a second channel by applying a pressure differential between the first and second reservoirs, while simultaneously preventing flow into the third channel by applying a pressure to the third reservoir which equals the pressure at the junction of the three channels. By switching one or more driving pressures, the flow to the second channel can be stopped and the liquid flow redirected to the third channel. This invention further includes switches wherein more than three channels are included in the flow network, either intersecting in a single junction or in multiple junctions.
460 Citations
39 Claims
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1. A liquid microswitch comprising:
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a first, a second and a third microchannel, each having a junction end and a port end, said first, second and third microchannels joined at said junction ends to form a first junction; a first, a second and a third liquid reservoir, attached to the port ends of said first, second and third microchannels, respectively; a pressure control means for applying a first driving pressure, P1, a second driving pressure, P2, and a third driving pressure, P3, to said first, second and third liquid reservoirs, respectively, wherein, in a first switching state, P1 is greater than or less than P2, and P3 is approximately equal to PJ, the pressure at said first junction; and a switching means, connected to said pressure control means, for switching said first, second or third driving pressure to a second switching state, wherein P1 '"'"' is greater than or less than P3 '"'"', and P2 '"'"' is approximately equal to PJ '"'"'. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A method of switching the liquid flow route at the junction of first, second and third microchannels, said method comprising the steps of:
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applying a first driving pressure, P1, a second driving pressure, P2, and a third driving pressure, P3, behind said first, second and third microchannels, respectively, wherein P1 is greater than or less than P2, and P3 is approximately equal to PJ, the pressure at said junction; and switching said first, second or third driving pressure to a second switching state, wherein P1 '"'"' is greater than or less than P3 '"'"', and P2 '"'"' is approximately equal to PJ '"'"'.
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Specification