| 摘要 |
An improved presettable, pressure-responsive retrievable fluid control valve contains a plurality of spring housing sections having individual springs disposed therein. Each of the springs is connected in mechanical parallel with each other spring. To select the preset pressure threshold at which the valve opens in response to a column of fluid in a tubing in which the valve is disposed, the number of springs and zero to two compression spacer members are chosen for each spring. The valve also includes a bypass section having an inner bypass mandrel connected by a frangible member to an outer bypass port member. Connected to the outer bypass port member is a sealing member for seating the valve in a seating nipple of a tubing. The bypass mandrel and the outer bypass port member are normally held by the frangible member in a fixed relationship so that ports through the bypass mandrel and the outer bypass port member are axially offset in a closed, or non-fluid conducting, position. When the valve is to be removed from the tubing, a force is applied to the bypass mandrel so that the frangible member is broken, thereby allowing relative movement between the bypass mandrel and the outer bypass port member. In this condition, the ports are aligned to allow a pressure equalizing fluid to flow on both sides of the sealing member so that the valve can be more easily retrieved from the seating nipple of the tubing.
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