Equalizing means for well safety valves

Claim 2

In a well safety valve for controlling fluid flow through a well tubing and having a housing, a first valve being movable between an open and closed position for controlling flow through the housing and tubing, a flow tube telescopically movable in the housing, said tube when in the downward position holds the valve in the open position and when in the upward position allows the valve to close, first actuation means acting on the tube for closing of said valve, second actuating means acting on the tube in a direction to open said valve, the improvement of equalizing means for reducing the pressure differential across said first valve while opening said first valve comprising, an equalizing valve between the housing and the tube, said equalizing valve being closed when the tube moves to the upward position and opens as the tube moves to the downward position, said equalizing valve opening prior to the opening of the first valve, a passageway in said safety valve through the equalizing valve for communicating pressure from below the first valve to a point inside said tubing above the first valve, said passageway including a first port in the housing upstream of the equalizing valve and in fluid communication with the tube whereby pressure in the passageway passes through the first port and acts on the tube in a direction to keep the tube upward when the equalizing valve is closed, said passageway including a second port in the tube downstream of the equalizing valve, said second port being smaller than the first port thereby dampening the movement of the tube as it moves downwardly to the open position.

Claim 3

In a well safety valve for controlling fluid flow through a well tubing and having a housing, a first valve being movable between an open and closed position for controlling flow through the housing and tubing, a flow tube telescopically movable in the housing, said tube when in the downward position holds the valve in the open position and when in the upward position allows the valve to close, first actuation means acting on the tube for closing said valve, second actuation means including a piston acting on the tube in a direction to open said valve, the improvement of equalizing means for reducing the pressure differential across said first valve while opening said first valve comprising, a passageway in said safety valve in communication between a point upstream of said first valve and a point interiorly of the tube and downstream of said first valve, an equalizing valve between the housing and the tube in said passageway, said equalizing valve being closed when the tube moves to an upward position and opens as the tube moves to the downward position, said equalizing valve opening prior to the opening of the first valve, and said passageway upstream of the equalizing valve being in communication at all times with the piston whereby pressure in the passageway acts on the piston in a direction for moving and holding the equalizing valve in a closed position.

Claim 4

In a well safety valve for controlling fluid flow through a well tubing and having a housing, a first valve being movable between an open and closed position for controlling flow through the housing and tubing, a flow tube telescopically movable in the housing, said tube when in the downward position holds the valve in the open position and when in the upward position allows the valve to close, first actuation means acting on the tube for closing said valve, second actuation means including a piston acting on the tube in a direction to open said valve, the improvement of equalizing means for reducing the pressure differential across said first valve while opening said first valve comprising, a passageway in said safety valve in communication between a point upstream of said first valve and a point interiorly of the tube and downstream of said first valve, an equalizing valve between the housing and the tube in said passageway, said equalizing valve being closed when the tube moves to an upward position and opens as the tube moves to the downward position, said equalizing valve opening prior to the opening of the first valve, and said passageway upstream of the equalizing valve being in communication at all times with the piston whereby pressure in the passageway acts on the piston in a direction for moving and holding the equalizing valve in a closed position.

Claim 5

The apparatus of claim 2 including, a restriction in the passageway downstream of said piston for dampening the movement of the tube as the tube moves in a direction to open the first valve.

Claim 6

The apparatus of claim 3 wherein the restriction is positioned downstream of the equalizing valve.

Claim 7

In a well safety Valve for controlling fluid flow through a well tubing and having a housing, a flapper valve being movable between an open and closed position for controlling flow through the housing and tubing, a flow tube telescopically movable in the housing, said tube when in the downward position holds the flapper valve in the open position and when in the upward position allows the flapper valve to closed, first actuation means acting on the tube for closing said valve, second action means including a piston on the tube exposed to fluid pressure in a conduit extending from the well surface and acting on the piston in a direction to open said valve, the improvement of equalizing means for reducing the pressure differential across said first valve while opening said first valve comprising, a passageway in said safety valve in communication between a point upstream of said flapper valve and a point interiorly of the tube and downstream of the flapper valve, an equalizing valve between the housing and the tube in said passageway, said equalizing valve being closed when the tube moves to an upward position and opens as the tube moves to a downward position, said equalizing valve opening prior to the opening of the flapper valve, said passageway upstream of the equalizing valve being in communication at all times with the piston whereby pressure in the passageway acts on the piston in a direction for moving and holding the equalizing valve in a closed position, and a restriction in the passageway downstream of said piston for dampening the movement of the tube as the tube moves in a direction to open the flapper valve.

Claim 8

In a well safety Valve for controlling fluid flow through a well tubing and having a housing, a flapper valve being movable between an open and closed position for controlling flow through the housing and tubing, a flow tube telescopically movable in the housing, said tube when in the downward position holds the flapper valve in the open position and when in the upward position allows the flapper valve to closed, first actuation means acting on the tube for closing said valve, second action means including a piston on the tube exposed to fluid pressure in a conduit extending from the well surface and acting on the piston in a direction to open said valve, the improvement of equalizing means for reducing the pressure differential across said first valve while opening said first valve comprising, a passageway in said safety valve in communication between a point upstream of said flapper valve and a point interiorly of the tube and downstream of the flapper valve, an equalizing valve between the housing and the tube in said passageway, said equalizing valve being closed when the tube moves to an upward position and opens as the tube moves to a downward position, said equalizing valve opening prior to the opening of the flapper valve, said passageway upstream of the equalizing valve being in communication at all times with the piston whereby pressure in the passageway acts on the piston in a direction for moving and holding the equalizing valve in a closed position, and a restriction in the passageway downstream of said piston for dampening the movement of the tube as the tube moves in a direction to open the flapper valve.