Pressure-resistant piston media separator, linear drive for a ship's steering gear and submarine

Description

[0001] The invention relates to a pressure-resistant piston media separator. For example, in a linear drive for a ship's steering gear, a mechanical movement occurs against the external pressure. To avoid working against the external pressure, the hydraulic fluid in a pressure-resistant piston media separator is brought to approximately the external pressure by subjecting the hydraulic fluid in the pressure-resistant piston media separator to external pressure via the ambient medium. A corresponding linear drive for a ship's steering gear is known from DE 10 2016 204 248 A1. There, the term "pressure compensation tank" is used as an alternative term for the pressure-resistant piston media separator. The piston of the pressure-resistant piston media separator is moved in one direction by incoming hydraulic fluid and in the other by the ambient medium.However, since this piston must also be extremely leak-proof, the piston exhibits a corresponding frictional resistance. As a result, at low external pressure, i.e. very shallow diving depths (including when surfaced), the pressure exerted by the ambient medium, the ambient water, on the piston may not be sufficient to move it. This can lead to negative pressure on the hydraulic fluid side, resulting in outgassing and, as a result, bubble formation. This leads to two problems. Firstly, the dissolution of the bubbles by redissolving in the hydraulic fluid is very slow. Secondly, the bubbles lead to behavior that is not exactly predictable. In particular, locking the rudder position, which is achieved by shutting off the hydraulic system, is made more difficult. However, if gas bubbles are present in this area, the rudder position can change unintentionally.

[0002] From DE 103 49 591 A1 a submarine with a rudder and an actuator for the rudder is known.

[0003] An underwater pressure compensation system is known from US 2006 / 231265 A1.

[0004] A seawater-supported storage system is known from WO 2016 / 133400 A1.

[0005] A sensor system for a double-cylinder storage system is known from WO 2020 / 185732 A1.

[0006] An underwater pressure storage system is known from US 2008 / 104951 A1.

[0007] An underwater fuel storage system is known from US 4 649 704 A.

[0008] From DE 10 2013 011115 A1 a device for adjusting a medium pressure relative to an ambient pressure is known.

[0009] The object of the invention is to create a pressure-resistant piston media separator which operates reliably at high ambient pressures (great diving depths) but above all also at low ambient pressures (shallow diving depths up to surface travel).

[0010] This object is achieved by the pressure-resistant piston media separator having the features specified in claim 1, by a linear drive having the features specified in claim 10, and by a submarine having the features specified in claim 11. Advantageous further developments emerge from the subclaims, the following description, and the drawing.

[0011] The pressure-resistant piston media separator according to the invention has a first piston cylinder with a first piston. The first piston and the first piston cylinder preferably have a round cross-section, but the invention is not limited thereto. Theoretically, it is only necessary that the internal cross-section of the first piston cylinder and the external cross-section of the first piston are the same. The pressure-resistant piston media separator has a first region and a second region, wherein the first region is separated from the second region by the first piston. Thus, the first region and the second region can be changed in size by displacement of the first piston. The pressure-resistant piston media separator according to the invention is preferably arranged in a watercraft, particularly preferably inside a pressure hull of a submarine. The first region is in contact with the external pressure.For this purpose, the first region is connected to the environment, for example and preferably via a line. This line particularly preferably has a pressure hull feedthrough, i.e. connects the pressure-resistant piston media separator according to the invention with the water located outside the pressure hull. The first region is particularly preferably in contact with surrounding water, in particular seawater. This results in pressure adjustment to the water depth. The direct contact of the device with the environment gives rise to technical challenges. Firstly, seawater is a corrosive medium, which must be taken into account when selecting the materials used. Secondly, it contains suspended matter and living organisms, which can cause problems, particularly due to fouling. The second region can be connected to a hydraulic system. The hydraulic system is, for example and preferably, a component of a linear drive of a ship's steering engine.In a ship's steering gear, the drive rods for the rudder blades must be moved through the submarine's pressure hull against the surrounding water pressure. By equalizing the hydraulic pressure to the surrounding water pressure in the pressure-resistant piston media separator, the force required and the work required to adjust the rudder blades are reduced. The pressure-resistant piston media separator also features a piston rod, which is connected to the first piston. The piston rod preferably runs through the second area.This has the advantage that the area of ​​the first piston which is wetted by the hydraulic fluid on the side of the second area is smaller than the area of ​​the first piston which is wetted by water on the side of the first area, so that the hydraulic fluid always has a certain low overpressure compared to the external pressure, which can reliably prevent the penetration of corrosive seawater into the hydraulic area in the event of a leak.

[0012] According to the invention, the pressure-resistant piston media separator comprises a second piston cylinder and a second piston. The second piston is also connected to the piston rod. Thus, the directions of movement of the first piston in the first piston cylinder and the second piston in the second piston cylinder are identical, preferably coaxial. The pressure-resistant piston media separator comprises a third region, wherein the third region is a closed gas volume. The third region can be changed in size by the movement of the second piston. In effect, the second piston cylinder, the second piston, and the third region thus represent an integrated gas spring.This allows for pressurisation in a very compact design via the stroke of the pressure-resistant piston media separator, in order to allow sufficient force to act on the first piston in the area of ​​low external pressure, for example when travelling above water, in order to move it against the friction when the hydraulic system takes hydraulic fluid from the second area and thus the force for adjusting the first piston must come from the ambient water.

[0013] The first piston and the second piston are arranged and connected via the piston rod in such a way that when the first area is enlarged, the third area is enlarged and when the first area is reduced, the third area is reduced.

[0014] Particularly preferably, the first piston cylinder and the second piston cylinder are arranged directly adjacent to one another.

[0015] According to the invention, the third region consists of a fourth region and a fifth region. The fourth region is arranged inside the second piston cylinder and the fifth region is arranged outside the second piston cylinder. The fourth region and the fifth region are connected to one another by a gas-conducting connection. This makes it relatively easy to adjust the pressure curve across all positions of the first piston and thus, for example, the rudder position of a ship's steering machine connected to it. In extreme cases, the size of the fourth region can therefore assume a minimum size even close to 0 when the second region is at its maximum size and the first region is at its minimum. Without the fifth volume, however, the pressure would become extremely high, which would be possible either through a larger dead volume, which would, however, increase the overall size.Or, as in this advantageous embodiment, it can be achieved by a connected volume in a fifth area, which reduces the overall size.

[0016] In a further embodiment of the invention, the fifth region is arranged to at least partially, preferably completely, surround the second piston cylinder. This allows for a particularly compact design.

[0017] In a further embodiment of the invention, the third region has a filling valve. This allows the pressure in the third region to be adjusted specifically. After filling, the filling valve is closed, so that the third region is a sealed gas volume.

[0018] In a further embodiment of the invention, the volume of the fifth region corresponds to one to five times the maximum volume of the fourth region.

[0019] In a further embodiment of the invention, the third region in the center position of the first piston in the first piston cylinder has a pressure of 2 bar to 5 bar. The center position of the first piston is understood to be the position midway between the two end positions of the first piston.

[0020] In a further embodiment of the invention, during use, the pressure in the first region is 1.5 bar to 3.5 bar higher than the pressure in the second region.

[0021] In a further embodiment of the invention, the third region is filled with an inert gas, preferably nitrogen. This makes it easy to avoid, for example, the corrosive properties of oxygen or atmospheric moisture.

[0022] In a further embodiment of the invention, the third region in the end position of the first piston with minimum second volume of the second region in the first piston cylinder has a pressure of 1.5 bar to 3.5 bar.

[0023] In a further embodiment of the invention, the first area is connected to the environment via a filter. In particular, the filter serves to keep out suspended particles and, above all, life forms that could become trapped inside. A disadvantage is that a filter creates a flow resistance. However, this can be easily compensated for by the effect of the third area.

[0024] According to the invention, the first piston has a first seal against the first region and a second seal against the second region. The first piston further has a test cavity located between the first seal and the second seal. The first piston and the piston rod have a feedthrough, wherein the feedthrough connects the test cavity to the side of the second piston facing away from the fourth region. As long as the two seals, the first seal and the second seal, are tight, nothing happens. If the first seal leaks, seawater gets into the test cavity and through the test cavity into the feedthrough to the outside and can be detected. It is therefore obvious that the first seal is leaking and must therefore be replaced. If the second seal leaks, hydraulic fluid gets into the test cavity and through the test cavity into the feedthrough to the outside and can be detected.It is therefore obvious that the second seal is leaking and must be replaced. This can be detected either visually or with the help of a suitable sensor.

[0025] In a further embodiment of the invention, the piston rod has a further passage. The further passage extends from the side of the first piston facing the first region to the side of the second piston facing away from the fourth region. The further passage is closable. This allows the air present in the first region to be removed easily and reliably when the first region is filled with seawater for the first time. This is particularly preferred when the pressure-resistant piston media separator is arranged vertically, i.e. the first region is arranged below the first piston.

[0026] In a further aspect, the invention relates to a linear drive for a ship's steering engine with a pressure-resistant piston media separator according to the invention.

[0027] The linear drive is preferably designed according to DE 10 2016 204 248 A1, only with a pressure-resistant piston media separator according to the invention.

[0028] In a further embodiment of the invention, the linear drive is electrically operated.

[0029] In a further embodiment of the invention, the linear drive has a first linear drive region and a second linear drive region, wherein the first linear drive region and the second linear drive region are filled with hydraulic fluid. When the linear drive is adjusted, the volumes of the first linear drive region and the second linear drive region change. The first linear drive region and the linear drive region are fluidically connected to the second region of the pressure-resistant piston media separator. Particularly preferably, the connection between the second region of the pressure-resistant piston media separator and the first linear drive region and the connection between the second region of the pressure-resistant piston media separator and the second linear drive region can each be closed separately, for example via valves.Preferably, the connection between the first linear drive area and the second linear drive area is also closed, so that the linear drive is thereby fixed in its position.

[0030] In a further embodiment of the invention, the volume of the second region of the pressure-resistant piston media separator is equal to or greater than the volume difference between the sum of the volumes of the first linear drive region and the second linear drive region at one stop of the linear drive and the sum of the volumes of the first linear drive region and the second linear drive region at the opposite stop of the linear drive.

[0031] In a further aspect, the invention relates to a submarine with a pressure-resistant piston media separator according to the invention. The pressure-resistant piston media separator is preferably arranged inside a pressure hull of the submarine, and the first region of the pressure-resistant piston media separator is connected to the environment of the submarine. For this purpose, the connection between the first region and the environment comprises a pressure hull passage.

[0032] The pressure-resistant piston media separator according to the invention is explained in more detail below using an embodiment shown in the drawing.

[0033] Fig. 1 exemplary pressure-resistant piston media separator

[0034] In Fig. 1An exemplary pressure-resistant piston media separator 10 is shown schematically, not to scale, in cross-section. The part of the pressure-resistant piston media separator 10 shown on the left consists of a first cylinder piston 20, in which a first piston 30 is movably arranged. On one side, here on the left, a first region 40 is arranged, which has the ambient pressure via a connection to the environment 60, for example a seawater connection. On the other side, the second region 50 is arranged, in which a hydraulic fluid is arranged, which can be supplied to and removed via a connection to the hydraulic system 70. The piston rod 80 also runs within the second region 50.

[0035] The second piston cylinder 90 is essential to the second piston 100. The second piston 100 is also connected to the piston rod 80 and thus performs the same movement as the first piston 30. In order to construct the gas-tight third region as compact as possible, in the example shown it consists of a fourth region 110 within the second piston cylinder 90 and a fifth region 120 surrounding the outside of the second piston cylinder. The gas pressure inside the third region can be specifically adjusted, in particular with nitrogen, via a filling valve 140. The fourth region 110 and the fifth region 120 are connected to one another via a gas-carrying connection 130.

[0036] To facilitate the initial filling of the first area 40 with water, the piston rod 80 has a further passage 150, which has a passage closure 160 on the side of the second piston 100 and is thus easily accessible from the outside, so that no water from the environment can penetrate into the interior during normal operation. Thus, the passage closure 160 must be able to withstand the maximum immersion pressure.

[0037] Furthermore, the first piston 30 has a first seal 170 against the water side of the first region 40 and a second seal 180 against the hydraulic side of the second region 50. In order to detect a leak in one of these seals 170, 180, a test cavity 190 is arranged between the seals 170, 180 and is connected to the feedthrough 200. In the event of a leak in the first seal 170, seawater can thus reach the area outside the second piston 100 and be easily detected. Likewise, in the event of a leak in the second seal 180, hydraulic fluid can reach the area outside the second piston 100 and be easily detected. Reference symbol

[0038] 10Pressure-resistant piston media separator 20First piston cylinder 30First piston 40First section 50Second section 60Connection to the environment 70Connection to the hydraulic system 80Piston rod 90Second piston cylinder 100Second piston 110Fourth section 120Fifth section 130Gas-carrying connection 140Filling valve 150Further feedthrough 160Feedthrough closure 170First seal 180Second seal 190Test cavity 200Feedthrough

Claims

1. Pressure-resistantpiston media separator (10), wherein the pressure-resistantpiston media separator (10) has a first piston cylinder (20) with a first piston (30), wherein the piston media separator (10) has a first region (40) and a second region (50), wherein the first region (40) is separated from the second region (50) by the first piston (30), wherein the first region (40) is in contact with the environment, wherein the second region (50) can be connected to a hydraulic system, wherein the pressure-resistant piston media separator (10) has a piston rod (80), wherein the piston rod (80) is connected to the first piston (30), wherein the pressure-resistant piston media separator (10) has a second piston cylinder (90) and a second piston (100), wherein the second piston (100) is connected to the piston rod (80), wherein the pressure-resistant piston media separator (10) has a third region, wherein the third region is a sealed gas volume, wherein the third region can be resized by the second piston (100) , wherein the third region comprises the fourth region (110) and a fifth region (120), wherein the fourth region (110) is arranged within the second piston cylinder (90), wherein the fifth region (120) is arranged outside the second piston cylinder (90), wherein the fourth region (110) and the fifth region (120) are connected to one another in a gas-conducting manner, characterised in that the first piston (30) has a first seal (170) against the first region (40) and a second seal (180) against the second region (50), wherein the first piston (30) has a test cavity (190) located between the first seal (170) and the second seal (180), wherein the first piston (30) and the piston rod (80) have a feedthrough (200), wherein the feedthrough (200) connects the test cavity (190) to the side of the second piston (100) facing away from a fourth region (110).

2. Pressure-resistant piston media separator (10) according to claim 1, characterised in that the fifth region (120) is arranged surrounding the second piston cylinder (90).

3. Pressure-resistant piston media separator (10) according to one of claims 1 to 2, characterised in that the third region has a filling valve (140).

4. Pressure-resistant piston media separator (10) according to one of claims 1 to 3, characterised in that the volume of the fifth region (120) corresponds to one to five times the maximum volume of the fourth region (110).

5. Pressure-resistant piston media separator (10) according to one of the preceding claims, characterised in that the third region in the central position of the first piston (30) in the first piston cylinder (20) has a pressure of 2 bar to 5 bar.

6. Pressure-resistant piston media separator (10) according to one of the preceding claims, characterised in that the third region is filled with an inert gas.

7. Pressure-resistant piston media separator (10) according to one of the preceding claims, characterised in that the third region in the end position of the first piston (30) with minimum second volume of the second region (50) in the first piston cylinder (20) has a pressure of 1.5 bar to 3.5 bar.

8. Pressure-resistant piston media separator (10) according to one of the preceding claims, characterised in that the first region (40) is connected to the environment via a filter.

9. Pressure-resistant piston media separator (10) according to one of the preceding claims, characterised in that the piston rod (80) has a further passage (150), wherein the further passage (150) extends from the side of the first piston (30) facing the first region (40) to the side of the second piston (100) facing away from the fourth region (110), wherein the further passage (150) can be closed.

10. Linear drive for a marine steering gear with a pressure-resistant piston media separator (10) according to one of the preceding claims.

11. Submarine with a pressure-resistant piston media separator (10) according to one of claims 1 to 9.