Pressure-balanced valve with improved sealing properties

A pressure-balanced valve, comprising:

• a valve body comprising a fluid inlet port and a fluid outlet port, and an inner cavity whereby the fluid inlet port communicates with the fluid outlet port, wherein the inner cavity is accessible through a top entry opening of the valve;
• a removable bonnet configured to close the top entry opening;
• a cage body arranged in the inner cavity and associated with the valve body in a fixed position, wherein the cage body defines a sliding seat for a closure member, wherein the cage body comprises at least one lateral opening for fluid flow;
• a closure member movable in the sliding seat between a closed position, whereby the lateral opening of the cage body is closed, and a full-open position, whereby the lateral opening of the cage body is totally free, wherein the closure member comprises at least one pressure-balancing channel extending between a first surface of the closure member and a second surface of the closure member, wherein the channel provides for communication between a first portion of the inner cavity delimited between the fluid inlet port and the first surface of the closure member and a second portion of the inner cavity delimited between the bonnet and the second surface of the closure member;
• a stem comprising a first end connected to the closure member at the second surface and a second end connected to a valve actuator, wherein the stem extends through the second portion of the inner cavity;
• a sealing assembly providing a fluid seal between the second portion of the inner cavity and a third portion of the inner cavity communicating with the outlet port,
• wherein the sealing assembly comprises:
• at least one sealing ring arranged about a first cylindrical portion of the closure member and contacting a first cylindrical portion of the sliding seat of the cage body, wherein the first cylindrical portion of the sliding seat is axially delimited by a first abutment surface and wherein the first cylindrical portion of the closure member is axially delimited by a second abutment surface,
• at least one thrust annular flange arranged in the second portion of the inner cavity in a position adjacent to the second surface of the closure member, wherein the thrust annular flange comprises an annular edge in contact with a first surface of the at least one sealing ring and wherein the thrust annular flange is axially floating relative to the closure member;
• and
• elastic means pushing the thrust annular flange towards the second surface,
• wherein the abutment surfaces are defined so that, when the closure member moves towards the closed position, the at least one sealing ring comes into abutment, at a side opposite to the side contacting the annular edge, with the first abutment surface before the closure member reaches the closed position.