HRP20010250A2 - Valve including a double gate valve and a drain - Google Patents

Description

The technical field to which the invention belongs

The subject of the invention belongs to the field of valves; latch; tap; floats; venting or venting devices, and especially in the area of latches that are guided longitudinally with respect to the seat when opening and closing.

The invention is marked and classified according to the International Patent Classification (IPC) with the classification symbol F 16 K 3/00.

Technical problem

The technical problem that is solved by this application consists of the following; how to design and build a valve that will prevent leakage of valves installed on the process pipeline, which is a problem that often occurs in industrial plants. Whether it is a leak through the valve into the pipeline or on the valve stem seal into the environment, the leak can result in serious disruptions in the technological process, cause environmental incidents, and cases with tragic consequences have been recorded.

The mentioned technical problem was solved by the construction of a valve with a double latch and drainage.

State of the art

In practice, the problem of valve leakage is solved in different ways, depending on the purpose for which the valve is installed, that is, depending on the level of safety that is to be achieved.

For example, if the valve is installed at the end of the pipeline, a blind flange is usually installed behind it to prevent further leakage. Between two pipelines that can be used in combination to transport two different media, two valves are installed one behind the other, or the pipelines are separated with blind flanges and, if necessary, reconnected with an inserted pipe, the so-called "spool piece".

Each of the mentioned methods has its advantages and disadvantages.

In the first case, in order to be able to connect, for example, a flexible overflow pipe or a protruding arm to the end of the pipeline where the valve with a blind flange is located, the flange must first be removed. If the valve fails, the medium in the pipeline will leak into the environment, and to prevent this, the pipeline must first be emptied. An even bigger problem appears after the transshipment is finished, when both pipelines, in front and behind the valve, are filled with liquid and it is necessary to separate them.

The installation of two valves on the pipeline certainly provides greater safety, but requires twice as much cost as well as more space for installation. In addition, the number of connecting flanges doubles, and thus the possibility of leaks on the flanges.

Separating the pipelines with blind flanges and, if necessary, reconnecting them with an inserted pipe represents the highest level of protection from the point of view of safety. However, every change in the purpose of the pipeline, i.e. every connection and separation, requires complete emptying of the pipeline and sometimes long-term and laborious installation of the inserted pipe or blind flanges. In case there are explosive or reactive gases in the pipeline, it is also necessary to inert and purge the pipeline, which causes additional material costs as well as time consumption.

As can be seen from the above, none of the mentioned methods actually solves the problem of leaking valves, but only prevents the further consequences of a possible leak to a greater or lesser extent.

The causes of valve leakage can be different, and the most common are mechanical damage to the sealing surface either on the side of the seat or the valve, a foreign body between the seat and the valve, an uncontrolled increase in pressure caused by the thermal expansion of the medium in the pipeline between two closed valves, etc.

In any case, regardless of the cause of the leak, the liquid in the pipeline due to the leak will gradually collect in the valve chamber until it is completely filled. With further leakage, the pressure in the chamber will increase until it becomes equal to the pressure in the part of the pipeline where the leakage occurred. This increase in pressure in the valve chamber can result in further leakage towards the pipeline on the other side of the valve where the pressure is lower, or into the environment, if the valve is installed at the end of the pipeline. In addition to the above, due to the increase in pressure in the valve chamber, there is a possibility of leakage on the seal of the valve chamber as well as on the valve stem seal, which will result in leakage of media into the environment.

Description of the solution to the technical problem

According to the construction envisaged by this invention, it is envisaged that the Valve with double latch and drainage (fig.1) prevents the collection of media and the increase of pressure in the latch chamber in case of leakage of the sealing surface, thus eliminating the risk of leakage towards the pipeline from the other side of the valve that is, leaks into the environment.

In the closed position of the valve, the non-return drainage valve (7) located between the two latches (1) is open and the liquid that may have leaked between the seat (2) and the latch is released into the drainage pipeline or into the drainage tank.

By opening the valve, the drainage valve closes automatically, allowing normal flow through the valve and pipeline.

Figure 1 shows a longitudinal section of a valve with a double valve and drainage.

Figure 2 shows a cross-section of the A-A valve shown in Figure 1.

Figure 3 shows a cross-section of the B-B valve shown in Figure 1.

Figure 4 shows the non-return drainage valve (pos. 7) with its components.

Figure 5 shows the pole (pos. 4) with which the valve latches are connected.

Figure 6 shows the latch (pos. 1) of the valve.

Fig. 7 shows the external (pos. 2) and internal (pos. 3) alignment of the latch.

Figure 8 shows one of the possibilities of using a valve with a double gate valve and drainage.

As shown in the above pictures, the valve with double latch and drainage consists of two latches (1) interconnected by a rod (4), which in the closed position of the valve fit between the outer (2) and inner (3) seats. The outer seat is a full circular sealing surface, while the inner seat is cut on the upper part in order to allow the rod connecting the valves to pass through it when the valve is opened. The pole is connected to the valve stem (5) on the upper side, while the stem extension (6) is twisted on its lower side, which in the closed position of the valve pushes the ball (7.1) of the non-return drainage valve (7) and thus enables the release of leaked liquid into the drainage pipeline.

When opening the valve, by lifting the latch, the stem extension is pulled into the valve housing and the ball of the drainage valve is pushed by the spring (7.2) into the upper position, and the drainage valve closes.

In order to ensure the tightness of the drainage valve at different pressures, the force of the spring can be regulated with a threaded washer (7.3) on which the spring rests.

The latches, which can be conical or flat in cross-section, are circular in shape with a groove on the side part into which the guide (8) located on the inside of the valve body enters, and whose role is to ensure the parallel movement of the latch.

A valve with a double latch and drainage can be operated using a hand wheel (9), and with larger valves, it is also possible to operate it in another way, for example, using a hydraulic or pneumatic actuator.

Figure si.8 shows a simplified process diagram of the installation for transshipment of liquefied gases, in this case propane (C3) and butane (C4) with the use of a valve with a double latch and drainage (A). As can be seen from the diagram, any gas can be transshipped. separately in a separate pipeline without the risk of mutual contamination, and if necessary, it is also possible to mix propane and butane in the desired ratio during transshipment, which is often the case in practice. Any leaked gas on the valve latch will be discharged into the drainage pipeline, which can be taken directly to the torch (B) or can be collected in the drainage tank (D), which is connected to the torch through the vapor phase. In the case of transshipment of completely cooled gases, where the pressure in the gas tanks is low, 50 to 100 mbar, it is also possible to return the gas to the tank. The same is the case with other media that have a high boiling point, eg oil, most chemicals, etc.

If necessary, the valve with double latch and drainage can also be used in such a way as to store inert gas in the drainage tank, eg nitrogen under a pressure higher than the pressure of the medium in the pipeline. In this case, the valve chamber between the two latches will be filled with inert gas under pressure, which eliminates any possibility of the medium leaking either to another part of the pipeline or to the environment.

Claims (7)

1. Valve with double latch and drainage, indicated by the fact that in the closed position of the valve, the non-return drainage valve (7) located between the two latches (1) is open and the liquid that may have leaked between the seat (2) and the latch is discharged into drainage pipeline or into the drainage tank. By opening the valve, the drainage valve closes automatically, allowing normal flow through the valve and pipeline. 2. Valve according to claim 1, characterized by the fact that it consists of two latches (1) interconnected by a rod (4), which in the closed position of the valve fit between the outer (2) and inner (3) seats. The outer seat is a full circular sealing surface, while the inner seat is cut on the upper part in order to allow the rod connecting the latches to pass through it, when the valve is opened, with the upper side of the rod being connected to the valve stem (5) while it is on its on the lower side, the spindle extension (6) is twisted, which, in the closed position of the valve, pushes the ball (7.1) of the non-return drainage valve (7) and thus enables the release of leaked liquid into the drainage pipeline. 3. The valve according to requirements 1 and 2, characterized by the fact that when the valve is opened, when the latch is raised, the stem extension is pulled into the valve housing, and the ball of the drainage valve is pushed by the spring (7.2) into the upper position, which closes the drainage valve, but in order to ensure the tightness of the drainage valve at different pressures, the force of the spring can be regulated by the threaded washer (7.3) on which the spring rests. 4. Valve according to claims 1-3, indicated by the fact that the latches, which can be of conical or flat section, are circular in shape with a groove on the side part into which the guide (8) enters, which is located on the inside of the valve body, and whose role to ensure parallel travel of the latch. 5. The valve according to claims 1-4, characterized by the fact that the valve can be operated using a handwheel (9), and with valves of larger dimensions, it is also possible to operate in another way, for example, using a hydraulic or pneumatic actuator. 6. Valve according to requirements 1-5, characterized by the fact that in the case of transshipment of liquefied gases, each gas can be transshipped separately in a separate pipeline without the risk of mutual contamination, and if necessary, it is also possible to mix the mixture in the desired ratio during transshipment with it that the possibly leaked gas at the valve latch will be discharged into the drainage pipeline through which it can be taken directly to the flare (B) or it can be collected in the drainage tank (D) which is connected to the flare in the vapor phase, and in case of reloading of fully cooled gases, where the pressure in the gas tanks is low, 50 to 100 mbar, it is also possible to return the gas to the tank. 7. Valve according to claims 1-6, characterized by the fact that, if necessary, the valve with double latch and drainage can also be used in such a way as to store inert gas in the drainage tank, for example nitrogen under a pressure higher than the pressure of the medium in the pipeline, and in this case the valve chamber between the two latches must be filled with inert gas under pressure, which eliminates any possibility of media leakage either to another part of the pipeline or to the environment.