Pressure-sustaining valve

A valve construction, comprising a valve body with a passage communicating between inlet and outlet ports, an interior bridge dividing the space between said ports into an inlet chamber and an outlet chamber, said bridge having an opening defining a circular valve-member seat of first effective diameter, an elongate valve stem on an axis extending normal to the circle of said seat and centrally therethrough, a valve member carried by said stem on the downstream side of said seat and positionable to open or close the valve in accordance with stem-guided displacement with respect to said seat;

• first guide means coacting with the inlet-chamber end of said stem and with a body portion of the inlet chamber to retain said inlet-chamber end on said axis through a range of valve-stem displacement, said first guide means including fluid-pressure-responsive means exposed on one side to fluid within the inlet chamber and on its other side to fluid external to said body, said first guide means being of effective area less than that of said seat;
• second guide means coacting with the outlet-chamber end of said stem and with a body portion of the outlet chamber to retain said outlet-chamber end on said axis through a range of valve-stem displacement, said second guide means including fluid-pressure-responsive means exposed on one side to fluid within the outlet chamber and on its other side to fluid external to said body, said second guide means being of effective area substantially equal to that of said seat;
• and stemloading means continuously urging said valve member in the direction of seat engagement.

A valve construction, comprising a valve body with a passage communicating between inlet and outlet ports, an interior bridge dividing the space between said ports into an inlet chamber and an outlet chamber, said bridge having an opening defining a circular valve-member seat of first effective diameter, an elongate valve stem on an axis extending normal to the circle of said seat and centrally therethrough, a valve member carried by said stem on the downstream side of said seat and positionable to open or close the valve in accordance with stemguided displacement with respect to said seat;

• first guide means coacting with the inlet-chamber end of said stem and with a body portion of the inlet chamber to retain said inlet-chamber end on said axis through a range of valve-stem displacement, said first guide means including fluid-pressure responsive means exposed on one side to fluid within said inlet chamber and on its other side to fluid external to said body, said first guide means being of effective area less than that of said seat, second guide means coacting with the outlet-chamber end of said stem and with a body portion of the outlet chamber to retain said outlet-chamber end on said axis through a range of valve-stem displacement, said second guide means including fluid-pressure-responsive means exposed on one side to fluid within the outlet chamber and on its other side to fluid external to said body, said second guide means being of effective area substantially equal to that of said seat;
• and stem-loading means continuously urging said valve member in the direction of seat engagement.