Constant force syringe

Abstract

Various syringe systems are disclosed. One such syringe system may include a body having a hollow lumen and a distal end, a vacuum chamber disposed within the hollow lumen of the syringe body, a first plunger connected to a distal portion of the vacuum chamber, the first plunger forming a first seal against an inner surface of the syringe body and defining a fluid delivery volume between the first plunger and the distal end of the syringe body, a second plunger disposed within the vacuum chamber, the second plunger forming a second seal against an inner surface of the vacuum chamber and defining a proximal and distal volume compartments within the vacuum chamber, and a piston affixed to the second plunger, the piston configured to move the second plunger within the vacuum chamber, thereby altering a volume of the proximal volume compartment and a volume of the distal volume compartment.

What is claimed is: 
     
         1 . A syringe system comprising:
 a syringe body comprising a hollow lumen and a distal end, the syringe body being configured to house a fluid therein;   a vacuum chamber disposed within the hollow lumen of the syringe body;   a first plunger connected to a distal portion of the vacuum chamber within the hollow lumen of the syringe body, the first plunger forming a first seal against an inner surface of the syringe body and defining a fluid volume between the first plunger and the distal end of the syringe body;   a second plunger disposed within the vacuum chamber, the second plunger forming a second seal against an inner surface of the vacuum chamber and defining a proximal volume compartment and a distal volume compartment within the vacuum chamber;   a vent extending through a wall of the proximal volume compartment of the vacuum chamber, wherein the vent is configured to allow communication of air between an area outside the syringe system and the proximal volume compartment; and   a piston affixed to the second plunger and extending proximally out of the vacuum chamber, the piston configured to move the second plunger within the vacuum chamber, thereby altering a volume of the proximal volume compartment and a volume of the distal volume compartment.   
     
     
         2 . The syringe system of  claim 1 , further comprising a valve configured to regulate an amount of the air communicated between the area outside the syringe system and the proximal volume compartment. 
     
     
         3 . The syringe system of  claim 1 , wherein the vent comprises a side vent extending through a wall in the distal volume compartment of the vacuum chamber. 
     
     
         4 . The syringe system of  claim 1 , further comprising a tip at the distal end of the syringe body, wherein the tip is configured to allow fluid to fill the fluid volume therethrough upon movement of the first plunger in a substantially proximal direction. 
     
     
         5 . The syringe system of  claim 5 , wherein the fluid fills the fluid volume at a constant flow rate. 
     
     
         6 . The syringe system of  claim 5 , wherein the tip is further configured to attach to one or more tubes, needles, or nozzles for delivery of the fluid to a patient. 
     
     
         7 . The syringe system of  claim 1 , wherein a force exacted upon the piston in a substantially proximal direction causes the second plunger to move proximally within the vacuum chamber, thereby increasing the volume of the distal volume compartment and decreasing the volume of the proximal volume compartment, creating a pressure difference between the distal volume compartment and the proximal volume compartment, which causes the vacuum chamber and the first plunger to move in a proximal direction, thereby drawing in the fluid into the fluid volume. 
     
     
         8 . The syringe system of  claim 1 , wherein a force applied to the first plunger is determined by the pressure difference between the proximal volume compartment of the vacuum chamber and the distal volume compartment of the vacuum chamber. 
     
     
         9 . The syringe system of  claim 1 , wherein the vacuum chamber is detachable from the first plunger and the syringe is configured to accept vacuum chambers of different sizes within the hollow lumen of the syringe body. 
     
     
         10 . A syringe system comprising:
 a syringe body comprising a hollow lumen and a distal end, the syringe body being configured to house a fluid therein;   a vacuum chamber defined by a distal wall and a proximal thumb piece, the vacuum chamber at least partially disposed within the hollow lumen of the syringe body;   a first plunger disposed distally to the vacuum chamber within the hollow lumen of the syringe body, the first plunger forming a seal against an inner surface of the syringe body and defining a fluid volume between the first plunger and the distal end of the syringe body;   a second plunger disposed within the vacuum chamber, the second plunger defining a proximal volume compartment and a distal volume compartment within the vacuum chamber;   a side vent extending through a wall of the distal volume compartment of the vacuum chamber, wherein the side vent is configured to allow communication of air between an area outside the syringe system and the distal volume compartment; and   a piston extending distally out of the vacuum chamber and connected to the first plunger and the second plunger, the piston configured to move the second plunger within the vacuum chamber and the first plunger within the syringe body,   wherein a force exacted upon the vacuum chamber in a substantially proximal direction is configured to cause the vacuum chamber to move proximally within the syringe body, thereby increasing the volume of the proximal volume compartment and decreasing the volume of the distal volume compartment, creating a pressure difference between the proximal volume compartment and the distal volume compartment, which causes the second plunger, the piston, and the first plunger to move in a proximal direction, thereby drawing in fluid into the fluid volume.   
     
     
         11 . The syringe system of  claim 10 , further comprising a tip at the distal end of the syringe body, wherein the tip is configured to allow fluid to fill the fluid volume therethrough upon movement of the first plunger in a substantially proximal direction. 
     
     
         12 . The syringe system of  claim 11 , wherein the tip is further configured to attach to one or more tubes, needles, or nozzles for delivery of the fluid to a patient. 
     
     
         13 . The syringe system of  claim 10 , wherein the vacuum chamber is detachable from the first plunger and the syringe is configured to accept vacuum chambers of different sizes within the hollow lumen of the syringe body. 
     
     
         14 . The syringe system of  claim 10 , wherein the fluid fills the fluid volume at a constant flow rate. 
     
     
         15 . The syringe system of  claim 10 , wherein the piston is detachable from one of the first plunger and the second plunger. 
     
     
         16 . The syringe system of  claim 10 , wherein a force applied to the first plunger is determined by the pressure difference between the proximal volume compartment of the vacuum chamber and the distal volume compartment of the vacuum chamber.