CORE BARREL VALVE ASSEMBLY

摘要

A valve assembly for use in an inner tube member of a core barrel head assembly positionable within a drill string of a drilling apparatus. The valve assembly works using two separate surfaces A and B and a biasing element with a force FS. When hydrostatic pressure is present forces are created on these surfaces: FA and FB. These forces have a direct relationship with pressure, as an increase in pressure will increase the force and vice versa. The surface areas are designed such that: FA>FB+FS, which will maintain the valve closed while under a predetermined fluid pressure, indicating to the driller that the inner tube has landed. When the driller relieves the fluid pressure and the pressure decreases, the force difference between FA, FB and FS decreases until FA

主权项

1. A valve assembly for use in a core barrel head assembly positionable within a drill string of a drilling apparatus, the valve assembly comprising:
a landing shoulder; at least one upstream fluid flow port positionable within a fluid line of the drilling apparatus upstream of the landing shoulder; at least one downstream fluid flow port positionable within the fluid line of the drilling apparatus downstream of the landing shoulder; at least one fluid pressure communication port positionable within the fluid line of the drilling apparatus; a movable valve element having a first side in fluid communication with pressurized fluid through the at least one pressure communication port and having a first surface that is influenced in the supply direction by a force FA from said fluid, and a second side facing in the opposite direction, in fluid communication with pressurized fluid through the at least one upstream fluid flow port and having a second surface that is influenced in the opposite direction by a force FB from said fluid; at least one biasing element for opening the valve assembly by displacing the valve element from a closed position to an open position, wherein the area of said second surface is greater than that of said first surface so that the force influencing the valve element in a closing direction, in the form of the force FB from the pressurized fluid acting on said second surface exceeds the force influencing the valve element in an opening direction, in a form of combining a force Fs from the biasing element and the force FA from the pressurized fluid acting on said first surface, whereby the valve element is retained in the closed position of the valve when pressurized fluid is supplied and wherein the at least one fluid pressure communication port and the at least one upstream fluid flow port form two sets of ports, the first set for fluid pressure communication with the movable valve element, and the second set for fluid flow required for drilling in which the fluid flow is blocked or opened by the movable valve element.