Patent Description:
The present disclosure belongs to a forced sealing valve, and in particular relates to a double block and bleed (DBB) forced sealing valve and an operating device.

A DBB forced sealing valve has outstanding sealing performance. While the valve is in a closed position, its sealing integration can be verified with valve inline and under pressure, which ensures the reliability of valve closing. DBB forced sealing valves are needed for many important applications. For example, in a tank farm, different storage tanks are usually used to store different media which have to be strictly isolated to prevent any potential huge loss caused by contamination of the media. Hence, DBB forced sealing valves must be used for isolation valves of the tanks and shut-off valves of the tank farm. Similarly, in oil or natural gas metering, airport fuel systems, and other scenarios that require verifiable tight shut-off, the application of DBB forced sealing valves is always mandatorily required by major international codes and standards.

At present, DBB forced sealing valves on the market are a kind of expansion plug valves, as shown in <FIG>. Its structural feature is that the valve core is composed of a wedge plug and two discs on both sides. The valve core rotates friction free between the on/off positions. At the closed position, the wedge plug is driven down by the valve stem, and the discs are pushed through the wedge inclined surfaces to achieve a forced seal. The valve stem has to complete complex rotational and linear movements through a complicated operating mechanism during the entire valve opening and closing operations. Since the linear movement of the valve stem is in the same direction as the escape of medium, leaking at the stem of this kind of valve can easily occur. Besides, the complicated operating mechanism is arranged at the valve stem, so that the size of the valve stem part of this kind of valve is huge, usually more than double the height of the valve body. In addition, the valve core has to adopt a geometric shape similar to that of a plug valve. Limited by its geometric structure, if the flow passage of this kind of valve adopts a full port, the valve body will be very large. Therefore, such valves usually have to adopt reduced port designs, such as a rectangle or a rhombus passage. Such a compromise design has a huge impact on the flow capacity of the valve.

<CIT> discloses a DBB forced sealing valve, including: a valve body; valve seats; a valve core arranged in the valve body; an upper sealing member driving part and a lower sealing member driving part arranged in the valve body and located on either side of the valve core; sealing members arranged between the valve seats and the upper and the lower sealing member driving parts; wherein, the upper sealing member driving part and the lower sealing member driving part can move along a rotation axis of the valve core, and the upper sealing member driving part and the lower sealing member driving part drive the sealing members to press against or to retract from the valve seats.

The purpose of the present disclosure is to propose a technical solution for a DBB forced sealing valve and an operating device, optimize the structural design of DBB forced sealing valves, improve the sealing reliability at the valve stem, improve the flow capacity of the valve, and make the operating mechanism simple and reliable in structure.

In order to achieve the above purpose, the technical solution of the present disclosure is: a DBB forced sealing valve characterised in that the upper sealing member driving part is provided with an upper driving track for driving the sealing members and the lower sealing member driving part is provided with a lower driving track for driving the sealing members and wherein the upper driving track and the lower driving track are dovetail, the upper driving track is inclined to the axis of rotation of the valve core and the lower driving track is inclined to the axis of rotation of the valve core.

Furthermore, the valve core is provided with a flow passage; and the upper sealing member driving part and the lower sealing member driving part are located on each side of the flow passage.

Furthermore, the DBB forced sealing valve includes a valve stem that drives the valve core to rotate.

Furthermore, in order to drive the upper sealing member driving part and lower sealing member driving part to move along the valve core rotation axis, the DBB forced sealing valve further includes an upper driving shaft and a lower driving shaft located on the valve core and on each side of the flow passage. The upper driving shaft and the lower driving shaft drive the upper sealing member driving part and the lower sealing member driving part to move along the rotation axis of the valve core through threads.

Furthermore, to drive the upper sealing member driving part and the lower sealing member driving part along the valve core rotation axis in opposite directions, the threads of the upper driving shaft and the lower driving shaft are in opposite directions.

Furthermore, the lower sealing member driving part is provided with guiding holes; the upper sealing member driving part is provided with guiding bars correspondingly inserted into the guiding holes.

Furthermore, the valve body includes a valve bonnet; the valve bonnet is provided with a limiting groove; the upper sealing member driving part is provided with a limiting rod corresponding to the limiting groove to limit the rotation stroke of the upper sealing member drive part.

Furthermore, one end of the valve stem is provided with a hexagonal head; one end of the upper driving shaft is provided with an inner hexagonal hole; the hexagonal head is located in the inner hexagonal hole and fits with the inner hexagonal hole.

The DBB forced sealing valve includes a locking rocker arm set in the upper sealing member driving part; and a rocker arm base surface provided in the valve body. The rocker arm base surface is provided with a locking guide groove.

The valve core drives the upper and lower sealing member driving parts to rotate within a rotation stroke between an open position and a closed position. When the upper and lower sealing member driving parts rotate to the closed position, the valve core toggles the rocker arm to enter the locking guide groove, and the valve core continues to rotate towards the closing direction, driving the upper sealing member driving part to move along the rotation axis of the valve core. The locking rocker arm moves in the locking guide groove.

Furthermore, the locking rocker arm is provided with a rotating rocker. The valve core is provided with a rocker guide groove and a rocker guide surface. When the upper and lower sealing member driving parts rotate between the open position and the closed position, the rotating rocker is embedded in the rocker guide groove, and the locking rocker arm moves under the restriction of the base surface of the rocker arm. The valve core also drives the sealing member driving part to rotate. When the upper and lower sealing member driving parts rotate to the closed position, the rocker guide groove rotates the locking rocker arm through the rotating rocker, and the locking rocker arm enters the locking guide groove. The rotating rocker moves on the rocker guide surface.

Furthermore, to ensure that the locking rocker arm can leave the locking guide groove during the opening operation, the rocker guide groove is provided at a starting end of the rocker guide surface.

Furthermore, to ensure that the locking rocker arm can enter the locking guide groove during the closing operation, the opening end of the locking guide groove is provided with a transition groove. When the upper and lower sealing member driving parts rotate to the closed position, the locking rocker arm enters the locking guide groove through the transition groove.

The beneficial features of the present disclosure are: a balanced design is adopted for the valve core, which completely solves the problems of the rising valve stems used in the current DBB forced sealing valves. This greatly simplifies the structure of the valve stem and greatly improves the sealing reliability of the valve stem. More importantly, upper and lower sealing member driving parts are adopted to drive the motion and forced sealing of the sealing members via a two-way slope. This can effectively reduce the structural size of the valve and essentially optimise the geometric shape of the valve core. Consequently, the valve flow passage can naturally adopt a round shape to match the shape of the pipeline, which greatly improves the flow capacity of the valve and makes the overall size of the valve body very compact. The geometric optimization of the upper sealing member driving part, the lower sealing member driving part and the valve core also allows the valve body structure to differ from the complex casting valve body structure that the current DBB forced sealing valves have to adopt. The valve body of the DBB forced sealing valve in the present disclosure can flexibly adopt the side-entry structure, the top-entry structure or the all-welded structure of ordinary ball valves, and thus can easily adapt to a variety of applications. The valve core is used to drive the rocker arm; this mechanism makes the structure of the valve compact and the opening and closing of the valve convenient and reliable.

The present disclosure will be described in detail below with reference to drawings and embodiments.

As shown in <FIG>, a DBB forced sealing valve includes a valve body <NUM>, a valve seat <NUM>, and a valve stem <NUM>. The valve stem drives the valve core <NUM> to rotate. The valve core is provided with a flow passage <NUM>. An upper sealing member driving part <NUM> and a lower sealing member driving part <NUM> are provided on either side of the flow passage respectively. When the valve core rotates relative to the upper sealing member driving part and the lower sealing member driving part, the upper sealing member driving part and the lower sealing member driving part move along the rotation axis of the valve core, and the upper sealing member driving part and the lower sealing member driving part drive the sealing member <NUM> to press against or to retract from the valve seats.

An upper drive shaft <NUM> and a lower drive shaft <NUM> are provided on either side of the valve core flow passage respectively. The upper drive shaft and the lower drive shaft drive the upper sealing member driving part and the lower sealing member driving part using threads.

The threads direction of the upper drive shaft is opposite to the threads direction of the lower drive shaft.

The upper sealing member driving part is provided with an upper driving track <NUM> for driving the sealing member, and the upper driving track is inclined relative to the rotation axis of the valve core; the lower sealing member driving part is provided with a lower driving track <NUM> for driving the sealing member, and the lower driving track is inclined relative to the rotation axis of the valve core.

The upper driving track and the lower driving track are dovetail tracks.

As shown in <FIG>, a DBB forced sealing valve operating device, the DBB forced sealing valve is provided with a valve body <NUM>, a valve core <NUM> and an upper sealing member driving part <NUM>. The valve core is provided with a flow passage <NUM>. The above-mentioned upper sealing member driving part rotates between the open position (as shown in <FIG>) and the closed position (as shown in <FIG>). The valve core drives the upper sealing member driving part to rotate. The upper sealing member driving part is provided with a locking rocker arm <NUM>. The valve body is provided with a rocker arm base surface <NUM>; the rocker arm base surface is provided with a locking guide groove <NUM>. The valve body is provided with an open stop and closed stop. When the upper sealing member driving part rotates to the closed position, the valve core pushes the locking rocker arm into the locking guide groove (as shown in <FIG>), and the valve core continues to rotate in the closing direction (i.e. the R2 direction in <FIG>) to drive the upper sealing member driving part to move along the rotation axis of the valve core. The locking rocker arm moves in the locking guide groove (as shown in <FIG> and <FIG>).

The locking rocker arm is provided with a rotating rocker <NUM>. The valve core is provided with a rocker guide groove <NUM> and a rocker guide surface <NUM>. When the upper sealing member driving part rotates between the open position and the closed position (as shown in the <FIG> and <FIG>), the rotating rocker is embedded in the rocker guide groove. The locking rocker arm moves under the restriction of the base surface of the rocker arm, and the valve core drives the upper sealing member driving part to rotate. When the upper sealing member driving part rotates to the closed position, the rocker guide groove pushes the locking rocker arm to rotate using the rotating rocker, the locking rocker arm enters the locking guide groove, and the rotating rocker moves on the rocker guide surface.

The rocker guide groove is provided at the starting end of the rocker guide surface. When the valve core rotates in the opening direction (i.e. the R1 direction in <FIG>), the rocker guide groove pushes the rotating rocker, and the locking rocker arm moves away from the locking guide groove.

The opening of the locking guide groove is provided with a transition groove <NUM>, and in some working conditions, when the upper sealing member driving part rotates to the closed position, the locking rocker arm enters the locking guide groove through the transition groove.

As shown in <FIG>, a DBB forced sealing valve includes a valve body <NUM>, a valve seat <NUM> and a valve stem <NUM>.

The valve body described in this disclosure is a valve body of a broad concept, including a valve body <NUM>. The valve body is cylindrical. A valve bonnet 1A is provided on the upper side of the valve body. The valve bonnet and the valve body are provided with a through shaft hole <NUM>. The valve stem is installed in the shaft hole. An upper bearing block 1B is provided on the upper side of the valve body, and a lower bearing block 1C is provided on the lower side of the valve body. The upper bearing block and the lower bearing block are respectively provided with bearing holes (<NUM>, <NUM>). The valve body <NUM>, the valve bonnet 1A, the upper bearing block 1B and the lower bearing block 1C are fixedly connected as a whole to form a generalized valve body.

Sealing ring <NUM> is provided between the valve stem and the valve bonnet.

Either end of the valve body is respectively provided with a generalized valve seat <NUM> (a valve seat in this embodiment is an assembly of a valve seat and a valve end).

A valve core <NUM> is installed in the valve body. The valve core is installed in the valve body through the bearing hole of the upper bearing block 1B and that of the lower bearing block 1C. A valve core ball <NUM> is provided at the centre of the valve core. A flow passage <NUM> is provided at the centre of the valve core ball; the flow passage is a circular through hole and the diameter D of the flow passage is identical to the diameter of the pipe on which the DBB forced sealing valve is installed such that the medium in the pipe can flow smoothly. The upper end of the valve core ball is provided with an upper drive shaft <NUM>, and the lower end of the valve core ball is provided with a lower drive shaft <NUM>. The upper drive shaft and the lower drive shaft are provided with threads, and the threads direction of the upper drive shaft is opposite to that of the lower drive shaft. An inner hexagonal hole <NUM> is provided at the top of the upper drive shaft. A hexagonal head <NUM> corresponding to the inner hexagonal hole of the valve core is provided on the lower end of the valve stem. The valve stem drives the valve core <NUM> to rotate via the hexagonal head; the valve stem can also drive the valve core via other driving connections.

An upper sealing member driving part <NUM> and a lower sealing member driving part <NUM> are respectively provided on either side of the flow passage of the valve core. The upper sealing member driving part is provided with a threaded hole <NUM> to be meshed with the threads of the upper drive shaft of the valve core. The lower sealing member driving part is provided with a threaded hole <NUM> to be meshed with the threads of the lower drive shaft of the valve core. The lower sealing member driving part is provided with four guide holes <NUM>, and the upper sealing member driving part is provided with four guide rods <NUM> corresponding to the guide holes so that the upper sealing member driving part and the lower sealing member driving part can move coaxially and synchronously. The valve core drives the upper sealing member driving part and the lower sealing member driving part to move in opposite directions using threads.

Either side of the upper sealing member driving part is provided with an upper driving track <NUM> for driving the sealing members. The upper driving track is inclined to the rotation axis of the valve core at its upper end; the angle between the upper driving track and the rotation axis of the valve core is α1. Either side of the lower sealing member driving part is provided with a lower driving track <NUM> for driving the sealing members. The lower driving track is inclined to the rotation axis of the valve core at its lower end; the angle between the lower driving track and the rotation axis of the valve core is α2. In this embodiment, α1=α2.

It is also possible to adopt a scheme in which the thread pitch of the upper driving shaft differs from that of the lower driving shaft and α1 differs from α2 to realize the function of synchronously pushing out the sealing members.

The upper sealing member driving part and the lower sealing member driving part are respectively provided with a sealing member <NUM> on either side. The sealing members are provided with an upper guide groove <NUM> to be matched with the upper driving track <NUM>, and a lower guide groove <NUM> to be matched with the lower driving track <NUM>.

When the valve core rotates, it drives the upper sealing member driving part and the lower sealing member driving part to move along the rotation axis of the valve core in opposite directions. During the valve closing operation, the upper sealing member driving part and the lower sealing member driving part move away from the flow passage. The upper sealing member driving part and the lower sealing member driving part drive the sealing members to move outward, pressing against the valve seats. During the valve opening operation, the upper sealing member driving part and the lower sealing member driving part move towards the flow passage. The upper sealing member driving part and the lower sealing member driving part drive the sealing members to retract from the valve seats.

The upper driving track and the lower driving track are dovetail tracks, which are compact and provide stable transmission.

The DBB forced sealing valve of this embodiment retains the excellent sealing performance of the DBB forced sealing valves currently in the market. It provides a round passage for the medium in the valve. The diameter of the medium passage is identical to the diameter of the pipeline, allowing smooth flow of the medium. The upper sealing member driving part and the lower sealing member driving part drive the motion and the forced sealing of the sealing members via a two-way slope. This effectively reduces the structural size of the valve and is suitable for various pipeline installation occasions.

As shown in <FIG>, a DBB forced sealing valve operating device, the operating device of this embodiment is the operating device of the DBB forced sealing valve described in the first embodiment.

As described in the first embodiment, the forced sealing valve is provided with a valve body <NUM>, a rotatable valve core <NUM> and an upper sealing member driving part <NUM>. The valve core is provided with a flow passage <NUM>, and the valve core drives the upper sealing member driving part to rotate between the open position (shown in <FIG>) and the closed position (shown in <FIG>). When the valve core rotates relative to the upper sealing member driving part, it drives the upper sealing member driving part via the thread to make the sealing member move along the axis of rotation of the valve core, so that the sealing member moves towards or retracts from the valve seat, realizing the forced sealing or opening of the valve.

The DBB forced sealing valve requires a set of operating mechanism. During the closing operation, the valve stem in a one-way rotation stroke drives the sealing member to rotate <NUM>° to reach its closed position and achieves forced sealing. During the opening operation, the valve stem in a one-way rotation stroke lifts the sealing of the sealing member and drives the sealing member to rotate <NUM>° to reach its open position.

As the operating device of the DBB forced sealing valve, the upper sealing member driving part is provided with a locking rocker arm <NUM>; the axis of rotation of the locking rocker arm is perpendicular to the axis of rotation of the valve core. The locking rocker arm is provided with a rotating rocker <NUM>. The bottom surface <NUM> of the upper bearing block 1B of the valve body is the rocker arm base surface; the rocker arm base surface is provided with a locking guide groove <NUM> and an arc-shaped transition groove <NUM> is provided at the opening of the locking guide groove. The valve core ball <NUM> is provided with a rocker guide groove <NUM> and a rocker guide surface <NUM>, and the rocker guide surface is a spiral surface surrounding the valve core ball. The rocker guide groove is arranged at the starting end of the rocker guide surface, and this starting end refers to the front end of the valve core when the valve core rotates in the closing direction.

The upper sealing member driving part rotates between an open position and a closed position with a rotation stroke of <NUM>°. To limit the rotation stroke of the upper sealing member driving part, as a part of the generalized valve body, the valve bonnet 1A is provided with a limit groove <NUM>, and the upper sealing member driving part is provided with a limit rod <NUM> which corresponds to the limit groove <NUM>. The limit groove and the limit rod limits the rotation stroke of the upper sealing member driving part.

Other strategies for controlling the rotation stroke can also be adopted, such as controlling the rotation of the lower valve sealing member drive part or controlling the rotation of the sealing member.

When the DBB forced sealing valve is in the open position, as shown in <FIG>, the flow passage <NUM> of the valve core is aligned with the valve seats at both ends. When the upper sealing member driving part rotates between the open position and the closed position (as shown in <FIG> and <FIG>), the rotating rocker <NUM> of the locking rocker arm is embedded in the rocker guide groove <NUM>. At this moment, the locking rocker arm rotates below the rocker arm base surface, that is, the top end of the locking rocker arm rotates below the base surface <NUM> or is in sliding contact with the base surface <NUM>; the valve core drives the upper sealing member driving part to rotate and it also drives the lower sealing member driving part and the sealing member to rotate synchronously.

During the closing operation of the valve, the valve stem drives the valve core to rotate in the closing direction (R2 direction as shown in <FIG>). When the upper sealing member driving part turns to the closed position, it stops rotating. The rocker guide groove <NUM> of the valve core pushes via the rotating rocker <NUM> the locking rocker arm <NUM> to rotate. The locking rocker arm enters the locking guide groove <NUM>. The rotating rocker moves away from the rocker guide groove <NUM> (as shown in <FIG>) and moves on the rocker guide surface <NUM>. Under normal conditions, the upper sealing member driving part rotates freely with the valve core, and the locking rocker arm can also rotate freely with the upper sealing member driving part. The top end of the locking rocker arm does not contact the base surface <NUM> of the rocker arm. When the upper sealing member driving part turns to the closed position and stops rotating, the top end of the locking rocker arm has already passed the locking guide groove. The rocker guide groove <NUM> of the valve core pushes the rotating rocker <NUM>, and the top end of the locking rocker arm <NUM> rotates along the transition groove <NUM> into the locking guide groove <NUM>. However, under some working conditions, such as when the upper sealing member driving part is prevented from rotating freely due to the rotational resistance that the flow medium exerts on the upper sealing member driving part or due to the friction exerted by the bearing block on the upper sealing member driving part, the guide groove <NUM> will push the rotating rocker <NUM> to power the rotation of the upper sealing member driving part. At this moment, the top end of the locking rocker arm <NUM> is in sliding contact with the rocker arm base surface <NUM>. To avoid excessive friction between the rocker arm and the rocker arm base surface, a rolling bearing <NUM> is provided at the top of the locking rocker arm in this embodiment. During such motion, due to the force provided by the rocker guide groove <NUM>, the top of the locking rocker arm <NUM> can directly enter the locking guide groove <NUM>.

The valve core continues to rotate in the closing direction (i.e. the R2 direction as shown in <FIG>), and drives via the upper drive shaft <NUM> the upper sealing member driving part to move upwards along the valve core rotation axis. The locking rocker arm moves in the locking guide groove (as shown in <FIG>). At this moment, the valve core drives via the lower drive shaft <NUM> the lower sealing member driving part to move downwards along the valve core rotation axis. This achieves the mechanism described in the first embodiment: "the upper and lower sealing member driving parts move away from the flow passage. The upper and lower sealing member driving parts drive the sealing members to move outwards and to press against the valve seats to realize the forced sealing.

During the opening operation, the valve core rotates in the opening direction (i.e. the R1 direction in <FIG>). Since the locking rocker arm <NUM> is in the locking guide groove <NUM>, the position of the upper sealing member driving part is locked and so the upper sealing member driving part does not rotate with the valve core. The valve core simultaneously drives via the upper drive shaft <NUM> and the lower drive shaft <NUM> the upper and lower sealing member driving parts to move along the valve core rotation axis. This realizes the mechanism described in the first embodiment: "the upper and lower sealing member driving parts move towards the flow passage and drive the sealing members to retract from the valve seats. " When the position of the rocker guide groove <NUM> matches the position of the transition groove <NUM> (as illustrated in <FIG>), the rocker guide groove pushes the rocker. The locking rocker arm leaves the locking guide groove (as illustrated in <FIG>). The top of the locking rocker arm is lower than the rocker arm base surface <NUM>. The locking rocker arm stops rotating when contacts the upper sealing member driving part. The valve core continues to rotate in the opening direction. The rocker guide groove drives via the rotating rocker the upper sealing member driving part to rotate along with the valve core to the open position (refer to <FIG>).

Claim 1:
A DBB forced sealing valve, including:
a valve body (<NUM>);
valve seats (<NUM>);
a valve core (<NUM>) arranged in the valve body (<NUM>);
an upper sealing member driving part (<NUM>) and a lower sealing member driving part (<NUM>) arranged in the valve body (<NUM>) and located on either side of the valve core (<NUM>);
sealing members (<NUM>) arranged between the valve seats (<NUM>) and the upper and the lower sealing member driving parts (<NUM>, <NUM>);
wherein, the upper sealing member driving part (<NUM>) and the lower sealing member driving part (<NUM>) can move along a rotation axis of the valve core (<NUM>), and the upper sealing member driving part (<NUM>) and the lower sealing member driving part (<NUM>) drive the sealing members (<NUM>) to press against or to retract from the valve seats (<NUM>);
characterised in that the upper sealing member driving part (<NUM>) is provided with an upper driving track (<NUM>) for driving the sealing members (<NUM>) and the lower sealing member driving part (<NUM>) is provided with a lower driving track (<NUM>) for driving the sealing members (<NUM>) and wherein the upper driving track (<NUM>) and the lower driving track (<NUM>) are dovetail tracks, the upper driving track (<NUM>) is inclined to the rotation axis of the valve core (<NUM>) and the lower driving track (<NUM>) is inclined to the rotation axis of the valve core (<NUM>).