Valve structure of indwelling catheter

indwelling catheter comprising: a body hollow catheter (1) having a proximal end and a distal end, a catheter tube (2) mounted at the distal end of the catheter body (1), an elastic valve (3) mounted inside the catheter body (1) and a hole (4) displaceably mounted piston within the catheter body (1); wherein the catheter tube (2), the elastic valve (3) and the piston (4) are coaxially aligned in this order; characterized in that the insertion of a connector from the proximal end of the catheter body (1) in the catheter body pushes the piston (4) and the piston (4) presses the elastic valve (3) opening it.