Dual direction lift gas valve with cavitation prevention

A valve for controlling a flow of fluid comprising:

• a body having a sidewall;
• a chamber in the body;
• valve elements disposed in the chamber that are selectively moveable with respect to one another;
• sealing surfaces on the valve elements;
• a barrier to fluid communication between adjacent valve elements that is selectively formed by bringing sealing surfaces on the adjacent valve elements into sealing contact;
• a side port formed through a sidewall of the body that is in selective communication with the chamber;
• and
• a choke member selectively moveable from an interfering position, in which flow through the side port is substantially restricted, and a fluid flow position, in which flow through the side port is substantially unrestricted, when the sealing surfaces are positioned a threshold distance from one another so that a velocity of fluid flowing between the sealing surfaces is below a minimum velocity that causes erosion of the valve elements.

A valve for controlling a flow of fluid comprising:

• a body having a sidewall;
• a chamber in the body;
• first and second valve elements disposed in the chamber that are selectively moveable with respect to one another;
• sealing surfaces on the valve elements;
• a barrier to fluid communication between the valve elements that is selectively formed by bringing sealing surfaces on the adjacent valve elements into sealing contact;
• a means for compliantly maintaining the sealing surfaces in sealing contact that comprises
• a first resilient member in biasing contact with the first valve element so that a first biasing force is exerted on the first valve element in a direction towards the barrier, and
• a second resilient member on a side of the barrier opposite the first resilient member and in biasing contact with the second valve element so that a second biasing force is exerted on the second valve element in a direction towards the barrier;
• and
• side ports formed through the sidewall of the body that are in selective communication with one another.