Systems and Methods for a Variable Flow Resistor

Abstract

The systems and methods of the present disclosure provides an independent passive variable resistor that can be interposed between a fluid reservoir at an inlet pressure and receptacle at an outlet pressure. The resistor can adjust resistance to the pressure difference from the input to the output so that the flow rate through it is a constant rate. The resistor can include a moveable element and a biasing mechanism located in a chamber to create a flow channel. Each side of the moveable element is exposed to the inlet and outlet pressures and moves within the flow channel to modify the resistance of the flow through the chamber in response to the pressures. The balance of these forces determines the position moveable element, which interacts with the fluid channel to determine the flow resistance through variable resistor. The biasing mechanism can provide the necessary pressure to establish equilibrium flow rate.

What is claimed is: 
     
         1 . A variable flow resistor device, the device comprising:
 a flow chamber having:
 an input configured for a fluid to flow through, into the flow chamber, and expose a portion of the flow chamber to an input pressure, 
 an output configured for the fluid to flow through, out of the flow chamber, and expose a portion of the flow chamber to an outlet pressure, 
 a cavity section having a cross-sectional area; and 
 a restrictor section having a reduced cross-sectional area smaller than the cross-sectional area of the cavity; 
   a moveable element configured to:
 traverse a range of positions within the flow chamber in the presence of the input pressure and the outlet pressure acting on the moveable element, 
 in the presence of a differential between the inlet pressure and the outlet pressure, occupy an overlap position producing a reduced flow channel between the restrictor section and the moveable element, the reduced flow channel configured to provide a substantially consistent output flow rate in the presence of a differential within a pressure differential operating range; and 
   a stop configured to define a stopped position and prohibit the moveable element in the stopped position from terminating output flow.   
     
     
         2 . The device of  claim 1 , wherein the stop defines a position closest to the input and prevents the moveable element from blocking fluid flow into the flow chamber. 
     
     
         3 . The device of  claim 1 , wherein the stop defines a position closest to the output and prevents the moveable element from blocking fluid flow out of the flow chamber. 
     
     
         4 . The device of  claim 1 , wherein the stop defines at least one of a minimum overlap position or a maximum overlap position. 
     
     
         5 . The device of  claim 1 , wherein the stop is adjustable and configured to move the stopped position. 
     
     
         6 . The device of  claim 1  further comprising a biasing mechanism within the flow chamber mechanically interfaced with the moveable element, the biasing mechanism configured to restrain movement of the moveable element and allow the moveable element to traverse within the range of positions in the presence of a sufficient pressure differential. 
     
     
         7 . The device of  claim 6 , wherein the biasing mechanism is coupled to at least one end of the moveable element and at least one end of the chamber. 
     
     
         8 . The device of  claim 6 , wherein the biasing mechanism includes at least one of a spring, an elastomer liner, an accordion, an elongating element, or a combination thereof. 
     
     
         9 . The device of  claim 1 , wherein the restrictor section includes at least one of an inwardly extending section of a sidewall of the flow chamber, or a structure connected to a sidewall of the chamber. 
     
     
         10 . The device of  claim 1 , wherein the moveable element is a piston. 
     
     
         11 . The device of  claim 1 , wherein a minimum length and a maximum length of the reduced flow channel is defined by a minimum overlap and a maximum overlap between the moveable element and the restrictor section. 
     
     
         12 . A system for implementing a controlled flow rate, the system comprising:
 a fluid source;   a variable flow resistor device in fluid communication with the fluid source, and includes:
 a flow chamber configured for placement in fluid communication with a fluid source and a fluid receptacle, the flow chamber having:
 an input configured for a fluid from the fluid source to flow through, into the flow chamber, and expose a portion of the flow chamber to an input fluid pressure; 
 an output configured for the fluid to flow through, out of the flow chamber, and expose a portion of the flow chamber to an outlet pressure; 
 a cavity section having a cross-sectional area; and 
 a restrictor section having a reduced cross-sectional area smaller than the cross-sectional area of the cavity; 
 
 a moveable element configured to:
 traverse a range of positions within the flow chamber in the presence of the input pressure and the outlet pressure acting on the moveable element; and 
 in the presence of a differential between the inlet pressure and the outlet pressure, occupy an overlap position producing a reduced flow channel between the restrictor and the moveable element, the reduced flow channel configured to provide a substantially consistent output flow rate in the presence of a differential within a pressure differential operating range; and 
 
 a stop configured to define a stopped position and prohibit the moveable element in the stopped position from terminating output flow; and 
   a pathway to direct fluid from the fluid source through the flow chamber and to a point of delivery.   
     
     
         13 . The system of  claim 12 , wherein the stop defines at least one of:
 a position closest to the input and prohibits the moveable element from blocking fluid flow into the flow chamber; or   a position closest to the output and prohibits the moveable element from blocking fluid flow out of the flow chamber.   
     
     
         14 . The system of  claim 12 , wherein the stop is adjustable and configured to adjust the stopped position. 
     
     
         15 . The system of  claim 12  further comprising a biasing mechanism within the flow chamber mechanically interfaced with the moveable element, the biasing mechanism configured to restrain movement of the moveable element and allow the moveable element to traverse within the range of positions in the presence of a sufficient pressure differential. 
     
     
         16 . The system of  claim 15 , wherein the biasing mechanism is coupled to at least one end of the moveable element and at least one end of the chamber. 
     
     
         17 . The system of  claim 15 , wherein the biasing mechanism includes at least one of a spring, an elastomer liner, an accordion, an elongating element, or a combination thereof. 
     
     
         18 . The system of  claim 12 , wherein a minimum length and a maximum length of the reduced flow channel is defined by a minimum overlap and a maximum overlap between the moveable element and the restrictor section. 
     
     
         19 . A method for delivering a constant fluid flow, the method comprising:
 providing a variable flow resistor having:
 a flow chamber in fluid communication with a fluid source and a point of delivery, the flow chamber comprising:
 an input configured for a fluid from the fluid source to flow through into the flow chamber and expose a portion of the flow chamber to an input fluid pressure; 
 an output configured for the fluid to flow through out of the flow chamber to a point of delivery and expose a portion of the flow chamber to an outlet pressure; 
 a cavity section having a cross-sectional area; and 
 a restrictor section having a reduced cross-sectional area smaller than the cross-sectional area of the cavity; 
 
 a moveable element within the flow chamber and configured to:
 traverse a range of positions within the flow chamber in the presence of the input pressure and the outlet pressure acting on the moveable element; 
 in the presence of a differential between the inlet pressure and the outlet pressure, occupy an overlap position producing a reduced flow channel between the restrictor and the moveable element, the reduced flow channel configured to provide a substantially consistent output flow rate in the presence of a differential within a pressure differential operating range; and 
 
 a stop within the flow chamber, the stop configured to define a stopped position and prohibit the moveable element in the stopped position from terminating output flow; 
   coupling the variable flow resistor to the fluid source via the input of the flow chamber; and   allowing the variable flow resistor to control the fluid flow within the flow chamber to deliver fluid from the fluid source to the point of delivery at a consistent fluid flow rate.   
     
     
         20 . The method of  claim 19 , wherein the variable flow resistor further comprises a biasing mechanism within the flow chamber mechanically interfaced with the moveable element, the biasing mechanism configured to restrain movement of the moveable element and allow the moveable element to traverse within the range of positions in the presence of a sufficient pressure differential.