Pressure controlled valve

A medical valve comprising:

• a housing forming first means for porting fluid, second means for porting fluid, and controlling means for receiving a positive or negative pressure;
• channeling means for channeling fluid within the housing between the first porting means and the second porting means;
• and
• sealing means configured to isolate the pressure means from the channeling means, the first porting means and the second porting means, the sealing means having a sealing means force,
• the sealing means configured to control fluid flow through the channeling means in response to four forces including:
• i) a first force generated on the sealing means from a differential fluid pressure between the first porting means and the controlling means times the exposed surface area of the sealing means,
• ii) a second force generated on the sealing means from a differential fluid pressure between the second porting means and the controlling means times the exposed surface area of the sealing means,
• iii) a third force generated by elastic deformation of the sealing means, and
• iv) a fourth force generated by a pressure drop due to fluid flow in the fluid channel due to the Venturi effect.

A method of controlling fluid flow through a valve, the method comprising:

• coupling tubing to a first port and to a second port of a housing of a closed valve, the housing forming a fluid channel between the first port and the second port;
• managing, via a control port configured to an externally applied positive and/or negative control pressure, a bias of a diaphragm having a shaped surface, the diaphragm positioned in the housing to isolate the control port from the fluid channel, first port, and the second port;
• applying a differential pressure between the first and second ports;
• and
• applying a control pressure to the control port to change the sealing force of the diaphragm, applying comprising producing fluid flow through the fluid channel as the diaphragm moves from a fully closed position to a partially opened position, and further to a fully open position.