Fluid injection pressure control syringe

A new fluid injection pressure control syringe, characterized by changing in a compression amplitude of a metal or non-metal spring with certain elastic coefficient, to reflect fluid pressure change in a syringe barrel or communicating vessels closed to the syringe barrel, comprising a syringe barrel, a pushrod with a sealing gasket, a spring, an indication pole with little sealing gasket, and a hole-cap, wherein a surface of the indication pole contains pressure scale or pressure range information;

• a main physical principle A, P=(F1+F2)/S;
• a physical principle B, F1=K(L0−L), wherein P is a pressure of fluid in the syringe barrel;
• F1 is a spring compression reaction force;
• F2 is a sliding friction force between the sealing gasket and a wall of a sub-barrel, wherein the sliding friction force is negligible when micro:
• S is a cross-sectional area of a sub-barrel inner lumen;
• K is an elastic coefficient of the spring, L0 is an original length of the spring, and L is a length after compression.