Low-flow fluid delivery system and low-flow device therefor

1. A hand portable apparatus comprising:

a pump having an inlet side and an outlet side, wherein the inlet side is configured to fluidly couple to a fluid supply;

a pressure sensor operably coupled to the outlet side and configured to measure a fluid pressure at the outlet side;

a pressure-actuated controller coupled to the pressure sensor, wherein the pressure-actuated controller is configured to:

turn on the pump in response to the fluid pressure at the outlet side below a first preselected pressure set point and turn off the pump in response to the fluid pressure at the outlet side above a second preselected pressure set point;

cycle between the first and second preselected set points unless a fluid flow rate at the outlet side exceeds a first value wherein the fluid pressure at the outlet side then remains below the first preselected fluid pressure set point and wherein the first preselected pressure set point is less than the second preselected pressure set point;

a sponge wherein the sponge comprises perforations; and

a low-flow device coupled to the outlet side and wherein the low-flow device comprises a perforated tube with perforations about the perforated tube onto which the perforations of the sponge are coupled and wherein the sponge is configured to dispense fluid through the perforations of the sponge;

wherein the low-flow device is fluidly coupled to the sponge, the sponge is fluidly coupled to a flow valve, and the flow valve is fluidly coupled to the outlet side, wherein:

the low-flow device is configured to dispense fluid from one or more openings in the low-flow device;

the flow valve is configured to deliver a flow-rate of the fluid adjustable to any value within a preselected range from about 0.01 gallons per minute (gpm) to about 2.5 gpm when the fluid pressure at the outlet side of the pump assembly decreases to the first preselected pressure set point and remains below the second preselected pressure set point; and

wherein the first value is less than about 2.5 gpm.

2. The hand portable apparatus of claim 1 wherein the flow valve is further configured to adjust the flow-rate of the fluid within the preselected range.

3. The hand portable apparatus of claim 1 wherein: the flow valve is fluidly coupled between the outlet side and the perforated tube, and the flow valve is configured to adjust the flow-rate of the fluid within the preselected range.

4. The hand portable apparatus of claim 1 wherein the first preselected fluid pressure set point is in the range from about 0.05 pounds per square inch (psi) to about 1099 psi and the second preselected fluid pressure set point is in the range from about 0.06 psi to about 1100 psi.

5. The hand portable apparatus of claim 1 , wherein the areal size of the perforations of the sponge is in the range from about 0.03 square millimeters (mm 2 ) to about 170 mm 2 .

6. The hand portable apparatus of claim 1 , wherein the fluid supply includes a heating system.

7. The hand portable apparatus of claim 1 , wherein the apparatus is configured to utilize 12v DC electrical power.

8. The hand portable apparatus of claim 1 , wherein the apparatus is operably connected to multiple power supplies and includes a user-operated switch to select between the multiple power supplies.

9. A system comprising:

a pump mechanism having an inlet side and an outlet side, wherein the inlet side is configured to fluidly couple to a fluid supply;

a pressure sensor operably coupled to the outlet side and configured to measure a fluid pressure at the outlet side;

an actuator mechanically coupled to the pump mechanism to drive the pump mechanism;

a controller coupled to the pressure sensor, wherein

the controller is configured with a preselected set of fluid pressure set points and one or more preselected sets of fluid flow rates, wherein the preselected set of fluid pressure set points comprises an ordered set of fluid pressure set points, the preselected set of fluid flow rates comprises an ordered set of fluid flow rates, and the controller is further configured to:

control the actuator to increase a fluid flow rate to a first flow rate in the preselected set of fluid flow rates when the fluid pressure at the outlet side falls to a lower one of corresponding fluid pressure set point in the preselected set of fluid pressure set points;

control the actuator to reduce the fluid flow rate to a second fluid flow rate in the preselected set of fluid flow rates when the fluid pressure at the outlet side rises to an upper one of corresponding fluid pressure set point in the preselected set of fluid pressure set points;

a sponge wherein the sponge comprises perforations; and

a low-flow device coupled to the sponge, the sponge fluidly coupled to the outlet side and wherein the low-flow device comprises a perforated tube with perforations about the perforated tube onto which perforations of the sponge are coupled and wherein the sponge is configured to dispense fluid through the perforations of the sponge, through the sponge perpendicular to a surface of the sponge; and a flow valve configured to deliver a flow rate of the fluid adjustable to any value within a preselected range from about 0.01 gpm to about 2.5 gpm, and wherein the first flow rate is less than about 2.5 gpm.

10. The system of claim 9 wherein:

when the fluid flow comprises a continuous fluid flow rate, when reduced, is continuously reduced to the second flow rate, and, when increased, is continuously increased to the first flow rate; and

when the fluid flow comprises pulsatile flow, the fluid flow rate when reduced, is switched to the first flow rate and, when increased, is switched to the second flow rate.

11. The system of claim 9 wherein the controller includes a driver configured to receive signals from the controller and map the signals to respective drive signals coupled to the actuator.

12. The system of claim 9 further comprising a driver coupled to the controller, the driver configured to receive signals from the controller and map the signals to respective drive signals coupled to the actuator.

13. The system of claim 9 , wherein the areal size of the perforations of the sponge is in the range from about 0.03 square millimeters (mm 2 ) to about 170 mm 2 .

14. The system of claim 9 , wherein the fluid supply includes a heating system.

15. The system of claim 9 , wherein the system is configured to utilize 12 v DC electrical power.

16. The system of claim 9 , wherein the system is operably connected to multiple power supplies and includes a user-operated switch to select between the multiple power supplies.