Subsea shut-off device

Abstract

A subsea shutoff device, in particular for use in water depths of more than 30 m for operating a valve with a gate with a waterproof, oil filled housing, a crank mechanism arranged in the housing, and a rotary actuator, wherein the rotary actuator is adapted to operate a gate of a valve via the crank mechanism.

Claims

1. A subsea shutoff device, in particular for use in water depths of more than 30 m for operating a valve with a gate, said subsea shutoff device comprising: a housing, which is waterproof and oil filled; a crank mechanism arranged in the housing; and a rotary actuator, wherein the rotary actuator is adapted to operate the gate of the valve via the crank mechanism, wherein the crank mechanism comprises a thrust crank mechanism with a crank, a thrust rod and a joint rod with a first and a second end, wherein the first end of the joint rod is fixed on the crank, and the second end of the joint rod is connected with the thrust rod via a joint, and the thrust rod is adapted to operate the gate of the valve, wherein the crank comprises a first end stop and a second end stop, and a rotational movement of the crank is only possible between the first and the second end stop, wherein the first end stop and the second end stop define a maximum angle of rotation for the crank of more than 180°, wherein the first end stop and the second end stop define a maximum angle of rotation for the crank, and the maximum angle of rotation is less than 240° max, and wherein the rotary actuator comprises an electric motor and a transmission.

2. The subsea shutoff device according to claim 1, wherein the valve and the gate are connected with the rotary actuator with the thrust rod.

3. The subsea shutoff device according to claim 1, wherein the gate shuts off the valve when the joint rod is at the first end stop, and wherein the gate opens the valve when the joint rod is at the second end stop.

4. The subsea shutoff device according to claim 1, wherein the crank mechanism comprises a first dead center and/or a second dead center, and the first end stop is arranged close to the first dead center and/or the second end stop is arranged close to the second dead center.

5. The subsea shutoff device according to claim 1, wherein the crank mechanism comprises a linear guiding restricting the thrust rod to a substantially one-dimensional movement.

6. The subsea shutoff device according to claim 1, wherein the subsea device is configured to withstand at least a depth pressure in 1000 m water depth.

7. The subsea shutoff device according to claim 1, wherein the subsea shutoff device is used for controlling a fluid in an oil or gas extraction plant in a water depth of at least 30 m.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Further advantages and features of preferred embodiments of the invention are explained below by means of the attached drawings. The drawings are not necessarily true to scale. Rather it is the functioning which shall be schematically shown. The figures show in:

(2) FIG. 1 a typical embodiment of the Subsea shutoff device,

(3) FIG. 2 another embodiment of the Subsea shutoff device, and

(4) FIG. 3 an embodiment of a crank mechanism and a motion sequence of the crank mechanism.

DESCRIPTION OF PREFERRED EMBODIMENTS

(5) In the following typical embodiments are described by means of the figures, wherein the invention is not limited to the embodiments. Rather, the scope of the invention is determined by the patent claims.

(6) In FIG. 1, a schematic view of a Subsea shutoff device in an oil or gas extraction plant 100 is shown. The Subsea shutoff device comprises a valve 10 with a gate 11 controlling the flow through the extraction plant 100. The gate 11 can be operated by a rotary actuator 30 via a crank mechanism 20. The crank mechanism 20 is arranged in a waterproof, oil filled housing 1.

(7) In the embodiment of FIG. 1 the rotary actuator 30 comprises an electric motor 31 and a transmission 32 for operating the crank mechanism 20. The electric motor 31 can be controlled by the motor control 40, wherein the rotary actuator 30 sets into rotation a crank of the crank mechanism 20.

(8) A typical embodiment of a crank mechanism is shown in detail in FIG. 3.

(9) In the embodiment of FIG. 1, the electric motor 31 and the transmission 32 are likewise arranged in the oil filled housing 1. The housing 1 comprises a sealed interface 2 to the valve 10. The movement of the crank mechanism 20 is transmitted to the gate 11 of valve 10 by the sealed interface 2.

(10) FIG. 2 shows an alternative embodiment in which the electric motor 31 and the transmission 32 are arranged in a separate casing or in individual casings (not shown in FIG. 3) compared with housing 1, and are connected with housing 1 via a sealed interface 3. Thus, the rotary actuator 30 can be replaceable without it being necessary that the oil filled housing 1 is opened.

(11) In the embodiment of FIG. 2, also an angular gear 33 is arranged in the housing 1 in order to rotate the rotation producible by the rotary actuator 30 by 90° in order to operate the crank mechanism.

(12) In further embodiments, the crank mechanism is permanently connected with the valve. Possibly, such embodiments comprise a simpler structure, wherein, however, in embodiments with an interface between the crank mechanism and the valve a simpler exchange of the rotary actuator with crank mechanism is possible.

(13) FIG. 3 shows more in detail an embodiment of a crank mechanism 20. The crank mechanism of FIG. 3 can, for example, be used in the embodiment of FIG. 1 or in the embodiment of FIG. 2.

(14) The crank mechanism 20 comprises a thrust crank mechanism with a crank 21, a thrust rod 23 and a joint rod 22. The joint rod 22 comprises a first and a second end. The first end of the joint rod 22 is fastened in an articulated manner on the crank 21. The second end of the joint rod 22 is connected with the thrust rod 23 via a joint 24.

(15) The thrust rod 23 is configured to operate a gate 11 of a valve 10 (not shown in FIG. 3). The joint rod 22 is pivotally connected with the crank 21. In other embodiments, the crank mechanism can also comprise more than two arms or more than two joints with corresponding support for the arms.

(16) The crank mechanism 20 of the embodiment of FIG. 3 comprises a first end stop 26a and a second end stop 26b. A movement of the crank 21 of the crank mechanism is only possible between the two end stops 26a, 26b.

(17) The upper representation of FIG. 3 shows the position of the crank 21 in the first end stop 26a; the lower representation shows the position of the crank 21 in the second end stop 26b. The representation in the center of FIG. 3 shows the movement of the crank 21 between the two end stops 26a, 26b.

(18) A position of the shutoff valve, namely “open” or “closed”, is allocated to each end stop 26a, 26b of the crank mechanism 20.

(19) The extension of the joint 24 to 180° so that the joint rod 22 and the thrust rod 23 are located on a straight line with the pivot point of the crank 21 defines a dead center. The two dead centers 27a, 27b are shown in dotted lines. In the dead centers 27a, 27b, no torque can be transmitted from the output end of the joint rod 22 to the crank 21 so that forces, which act on the gate (not shown in FIG. 3), are entirely received by the pivot bearing of the crank.

(20) The end stops 26a, 26b are located close to the dead centers 27a, 27b. Precisely, in the embodiment of FIG. 3, the end stops 26a and 26b are located by 20° each “behind” the dead centers 27a, 27b so that a total possible angle of rotation of the crank 21 of 180° plus 20° plus 20° corresponding to 220° in total, results.

(21) The first end stop can be located at the position close to the thrust rod or at the remote position relative to the thrust rod. The second end stop each is located at the other position.

(22) If the crank 21 at a position in one of the end stops 26a, 26b is loaded by a force from the gate (not shown in FIG. 3), no movement at all, if the force is pressing the crank 21 against the respective end stop 26a, 26b, or at most a movement up to the respective dead center 27a, 27b, is possible.

(23) In embodiments, the end stops or the pivot bearing of the crank take up forces on the output side possibly occurring, and a reverse rotation and/or a movement from a position adopted on an end stop are made difficult or prevented. Thus, the positions of the gate can be safely controlled with a large tolerance. Moreover, the valve in both positions is secured without the use of energy. Pressure on the valve by a fluid in the extraction plant, for example, a pipeline, alone cannot operate the gate.

(24) As shown in FIG. 3, the dead centers 27a, 27b of the typical embodiment shown in FIG. 3 are each on the opposite on the crank 21. Therefore, they are offset by an angle of rotation of 180°. The end stops 26a, 26b are positioned close to the dead centers 27a, 27b and behind the dead centers 27a, 27b. Thus, they define an angle of rotation of the crank 21 of more than 180°, in particular of more than 180° and less than 240°, in particular 220° max.

(25) A dead center 27a, 27b is typically reached in the embodiment of FIG. 3, when the joint rod 22 and the thrust rod 23 are in one line on the crank 21. The joint rod 22 rotates on one end together with the crank 21, and on the other end is pivotally connected with the thrust rod 23.

(26) Typically by a linear guiding, the thrust rod can only carry out a one-dimensional movement. In embodiments, the direction of movement can in particular correspond to the direction of movement of the gate.