Bubble based micropump

A micro-pump for pumping a liquid between two reservoirs, comprising:

• a channel connected between a first reservoir and a second reservoir the liquid being disposed within the channel;
• means for forming one or more vapor bubbles in the channel wherein
• the forming means or the channel provide an asymmetry for a pumping action of the liquid,
• wherein the forming means is a heater disposed at an asymmetric position along the channel and provides localized heat to the liquid at the asymmetric position and the heater is comprised of two heater units positioned proximate to a first end and a second of the channel in order to provide a bi-directional pump in which flow direction is dependent on which of the two heater units are energized.

A micro-pump for pumping liquid, comprising:

• a first channel having a first diameter;
• a second channel having a first diameter, the second diameter being larger than the second diameter;
• a chamber disposed between the first and second channels and having an asymmetric portion;
• and
• an energy source disposed at the asymmetric portion, the energy source heating the liquid disposed within the micro-pump thereby forming a vapor bubble.

A micro-pump for pumping liquid comprising:

• a channel positioned between a first reservoir and a second reservoir and adapted for having liquid being disposed therethrough;
• and
• at least one heater disposed proximate to the channel, the at least one heater providing localized heat to the liquid in the channel at an asymmetric position along the channel whereby the localized heat forms at least one vapor bubble,
• wherein the at least one heater is two heaters positioned proximate to a first end and a second and opposing end, respectively, of the channel in order to provide a bi-directional pump in which flow direction is dependent on which of the two heaters are energized.

A method of pumping liquid in a micro-pump in absence of a valve, the micro-pump including a channel for transporting the liquid between two reservoirs, the method comprising the steps of:

• providing localized heat to the liquid;
• forming a vapor bubble from the liquid at a location of the localized heat;
• and
• collapsing the vapor bubble,
• wherein the liquid is transported between the two reservoirs by the formation and collapsing of the vapor bubble
• wherein the providing localized heat is provided by a heater and the heater is heating the liquid within a conical section of the channel in order to form the vapor bubble.

A method of pumping liquid in a micro-pump, the micro-pump including a channel for transporting the liquid therein, the method comprising the steps of:

• providing localized heat to the liquid by electric current;
• forming a vapor bubble from the liquid at a location of the localized heat;
• collapsing the vapor bubble;
• and
• squeezing the electric current through a throat of the channel in order to provide the localized heat, wherein
• the electric current is provided at a conical section of the channel;
• the conical section of the channel is disposed between the throat and a first electrically conductive portion of the channel and the throat is disposed between a second electrically conductive portion of the channel and the conical portion, a diameter of the first electrically conductive portion being wider than a diameter of the second electrically conductive portion.