Valve

Abstract

valve (1) with - a valve body (3) which ◯ a channel (5), ◯ a first fluid path (23), ◯ a second fluid path (25) and ◯ includes at least one third fluid path (29), as well as with - a control element (13) slidably mounted in the channel (5), which ◯ comprises at least one sealing body (15) connected to it, which interacts with a first and second valve seat (17,19), - wherein the control element (13) comprises a first pressure plate (35) fixedly connected to it and a second pressure plate (41) fixedly connected to it, wherein - between the first pressure plate (35) and the sealing body (15) abutting the first valve seat (17) a pressurized first fluid section (27) in fluid communication with the first and second fluid paths (23,25) can be delimited, wherein - between the second pressure plate (41) and the sealing body (15) abutting the second valve seat (19) a pressurized second fluid section in fluid communication with the first and third fluid paths (23, 29) can be delimited, and wherein - the first and second printing plates (35,41) on the control element (13) are arranged at a distance from each other, wherein - a space (43) is enclosed between the printing plates (35,41), which ◯ is in fluid communication with a venting device (45) that prevents pressure build-up in the intermediate space (43), wherein ◯ the pressure given in the first fluid section (27) acts on the side of the first pressure plate (35) which is facing away from the space (43), and wherein ◯ the pressure given in the second fluid section acts on the side of the second pressure plate (41) which is facing away from the space (43). - characterized by the fact that The pressure prevailing in the first fluid section (27) acts on the sealing body (15) on the one hand and on the first pressure plate (35) on the other hand in such a way that the pressure forces acting on the control element (13) are opposite, wherein the effective areas of the sealing body (15) and the first pressure plate (35) are chosen to be of the same size, so that the pressure forces acting on the control element (13) via the sealing body (15) and the first pressure plate (35) are balanced, and wherein The pressure prevailing in the second fluid section acts on the sealing body (15) on the one hand and on the second pressure plate (41) on the other hand in such a way that the pressure forces acting on the control element (13) are opposite, whereby the effective areas of the sealing body (15) and the second pressure plate (41) are chosen to be of the same size, so that the pressure forces acting on the control element (13) via the sealing body (15) and the pressure plate (41) are balanced.

Description

[0001] The invention relates to a valve according to the preamble of claim 1.

[0002] Valves of the type discussed here are known (US 4,615,353 A, DE 29 03 296 A1, US 6,488,050 B1, GB 2,133,117 A, US 4,163,543 A, US 6,171,495 B1). They have a valve body with a channel and a control element slidably mounted therein, which includes a sealing element. This sealing element interacts with a first and second valve seat such that, in a first operating position, a fluid connection between a first and second fluid path in the valve body is opened, whereby, by contacting the sealing element against the first valve seat, a fluid connection between the first and a third fluid path is interrupted. In a second operating position of the sealing element, a fluid connection between the first and third fluid paths is opened, whereby, by contacting the sealing element against the second valve seat, a fluid connection between the first and second fluid path is interrupted.The control element has a first and second pressure plate attached to it, positioned at a distance from each other. Depending on the operating position of the sealing element, one of these pressure plates can be pressurized. It has been found that in valves of this type, the medium present in the valve body can diffuse through the pressure plates, leading to an unintended pressure increase on one side of the pressure plate and leakage on the opposite side. This generates switching problems, namely that the valve can no longer be switched when the pressure rises uncontrollably.

[0003] The object of the invention is therefore to create a valve of the type mentioned above, which is designed in such a way as to avoid the disadvantage mentioned above.

[0004] To solve this problem, a valve with the features of claim 1 is proposed. The valve has a valve body comprising a channel, a first fluid path, a second fluid path, and at least a third fluid path, as well as a control element slidably mounted in the channel, to which at least one sealing element is connected, which interacts with a first and a second valve seat. The control element also has a first pressure plate rigidly connected to it and a second pressure plate connected to it.The valve has a pressurized first fluid section between the first pressure plate and the sealing element at the valve seat, which is in fluid communication with the first and second fluid paths, and a pressurized second fluid section between the second pressure plate and the sealing element at the second valve seat, which is in fluid communication with the first and third fluid paths. The two pressure plates are arranged at a distance from each other on the control spool. A space is enclosed between the pressure plates, which is in fluid communication with a venting device. The pressure in the first fluid path acts on the side of the first pressure plate facing away from the space, and the pressure in the second fluid section acts on the side of the second pressure plate facing away from the space.

[0005] Depending on the operating position of the pressure body, one of the two pressure plates is pressurized. Since a gap is enclosed between the two pressure plates, any medium diffusing through them will always enter this gap, which is connected to a venting device, regardless of which plate is pressurized. This prevents pressure from building up on the side of a pressure plate facing away from the pressurized side, which could impair the valve's switching behavior.

[0006] It appears that the proposed valve can be designed as a three-way valve. However, it is also conceivable to use the chosen design with other valve types. Crucially, the space enclosed between the two pressure plates is connected to a venting device, preventing the build-up of pressure from a medium diffusing through the pressure plates that would impair the valve's switching behavior.

[0007] The valve according to the invention is characterized in that the pressure prevailing in the first fluid section acts on the sealing element on the one hand and on the first pressure plate on the other hand in such a way that the pressure forces acting on the control element via the sealing element and the first pressure plate are opposite in direction, wherein the effective areas of the sealing element and the first pressure plate are selected to be of equal size, so that the pressure forces acting on the control element via the sealing element and the first pressure plate are balanced. This design improves the switching behavior of the valve. Furthermore, the forces required to effect a switching operation of the valve are lower than without this balancing of the pressure forces acting on the control element. It is not essential that the forces acting on the control element are perfectly balanced.It is sufficient if the control element is relieved of stress, i.e., the pressure forces are essentially balanced, because this already achieves an improvement in the switching behavior of the valve.

[0008] The valve according to the invention is further characterized in that the pressure prevailing in the second fluid section acts on the sealing body on the one hand and on the second pressure plate on the other hand in such a way that the pressure forces acting on the control element are opposite, wherein the effective areas of the pressure body and the second pressure plate are selected to be of equal size, so that the forces acting on the control element via the sealing body and the second pressure plate are balanced. The statements made regarding the preceding preferred embodiment apply accordingly.

[0009] A preferred embodiment of the valve is characterized by the presence of a space, preferably an annular space, within the valve body, extending at least partially around the control element and forming the first fluid section between the first fluid path and the second fluid path. Such a valve design is very compact, requiring little installation space.

[0010] Another preferred embodiment of the valve is characterized in that the second fluid section comprises a cavity extending at least over a region of the longitudinal extent of the control element, which is in fluid communication on one side with a pressure chamber surrounding the control element, located on the side of the second pressure plate facing away from the space between the pressure plates, and on the other side with a fluid chamber surrounding the control element, bounded by the sealing body bearing against the valve seat. This fluid connection via the cavity in the control element allows the valve to be designed very compactly.

[0011] In another preferred embodiment of the valve, it is provided that it has a drive unit, preferably comprising an electromagnet, which is configured to axially displace the control element and move the sealing element into the first and / or second operating position. In principle, the way in which the control element is displaced within the channel in the valve body is not crucial for the valve's operation.

[0012] In principle, a manually operated actuator is also conceivable. However, in practical use, it is preferred that the actuator includes an electromagnet, allowing the valve to be controlled remotely via a control line for the electromagnet. In particular, it is not necessary for the valve to be manually accessible for switching.

[0013] The invention is explained in more detail below with reference to the drawing. The single figure shows a valve in longitudinal section.

[0014] The valve 1 shown in the figure has a valve body 3 which includes a channel 5. The central axis 7 of the channel 5 runs horizontally in the figure and also forms the central axis of the valve body 3. The channel 5 is preferably realized by a bore, in particular a stepped bore, and extends here from the left end 9 to the right end 11 of the valve body 3.

[0015] In the channel 5 there is a control element 13 which is slidably mounted in the valve body 3, on which at least one seal, here a sealing element 15, is attached, such that it cannot be unintentionally displaced on the control element 13 in the axial direction, i.e. in the direction of the central axis 7.

[0016] The figure shows that in a first functional position, the sealing element 15 interacts sealingly with a first valve seat 17, which is located to the left of the sealing element 15 in this figure. On the other hand, it is arranged at a distance from a second valve seat 19, so that the sealing element 15 does not have a sealing effect in the area of ​​the second valve seat 19.

[0017] The control element 13 is arranged concentrically in the channel 5, i.e., concentrically to the common central axis 7, so that a space 21 is formed that surrounds the control element 13 in the circumferential direction, i.e., around the central axis 7, at least partially, and is preferably designed as an annular space. This space 21 extends in the direction of the central axis 7 such that it is connected on the one hand to a first fluid path 23 and on the other hand to a second fluid path 25, thus forming a first fluid section 27 between the first fluid path 23 and the second fluid path 25.

[0018] The figure depicts a first functional state, that is, a first functional position, of the valve 1, in which the first fluid path 23 is in fluid communication with the second fluid path 25 via the first fluid section 27. The sealing element 15, connected to the control element 13, is in a first functional position in which the fluid connection between the first fluid path 23 and the second fluid path 25 is open because the sealing element 15 is not in contact with the second valve seat 19. However, since it is in contact with the first valve seat 17, a fluid connection between the first fluid path 25 and a third fluid path 29 is interrupted. In other words, a medium entering the first fluid path 23 cannot flow from the first fluid path into the third fluid path 29 because there is an interruption here, as the sealing element 15 is in contact with the first valve seat 17 on the left.

[0019] The figure shows that the sealing body 15 has a first sealing element 31 in the areas where it abuts the first valve seat 17 and a second sealing element 33 in the area where it can abut the second valve seat 19. It is quite possible to manufacture the surface of the sealing body 15 or the entire sealing body 15 from a material such that it exhibits a sealing effect when in contact with the first or second valve seat 17, 19.

[0020] The figure shows that the first fluid section 27 is closed off on its left side by the sealing element 15 resting against the first valve seat 17 on the left. Therefore, any medium present in the first fluid section 27 cannot reach the area of ​​the third fluid path 29 to the left.

[0021] On its right side, the first fluid section 27 is sealed by a preferably annular first pressure plate 35, which on one side abuts the control element 13 in a sealing manner and is preferably held in place by a clamping element 37. On the other side, the first pressure plate 35 is sealed to the valve body 3, preferably by a clamping element 39. The first pressure plate 35 is preferably designed as an elastic diaphragm that surrounds the control element 13 in an annular manner and preferably comprises or consists of an elastomer.

[0022] The sealing body 15 is preferably also ring-shaped and surrounds the control element 13.

[0023] The sealing element 15 and the first pressure plate 35 are arranged at a distance from each other – measured in the direction of the central axis 7 – such that the space 21 is formed with an axial length, measured in the direction of the central axis 7, into which the first fluid path 23 and the second fluid path 25 open, whereby the first fluid section 27 located between the first fluid path 23 and the second fluid path 25 is not interrupted. A pressure prevailing in the first fluid section 27 acts in the figure to the left on the sealing element 15 and to the right on the first pressure plate 35, whereby the effective area of ​​the sealing element 15 bearing against the first valve seat 17 corresponds as closely as possible to the effective area of ​​the first pressure plate 15.The forces exerted on the control element 13 by the sealing element 15 and the first pressure plate 35 at a pressure in the first fluid section 27 act in opposite directions, so that, provided the two effective areas are essentially equal, a substantially force-balanced state is achieved. A second pressure plate 41 is attached to the control element 13 at an axial distance, i.e., measured in the direction of the central axis 7. It is held in a sealing position against the control element 13 at its side closer to the central axis 7, preferably by the clamping element 37. At its radially outer end, the second pressure plate 41 is sealed against the valve body 3 of the valve 1, preferably clamped by the clamping element 39.

[0024] The clamping body 37 and the clamping element 39 are preferably ring-shaped. Crucially, the two pressure plates 35 and 41 are sealed against the control element 13 on their side facing the central axis 7 and sealed against the valve body 3 on their opposite side facing away from the central axis 7.

[0025] The second pressure plate 41 can preferably again be designed as a membrane, for which what has been said in connection with the first pressure plate 35 applies accordingly.

[0026] The two pressure plates 35 and 41 are arranged at a distance from each other, measured in the direction of the central axis 7, so that an intermediate space 43 is formed between them, which is closed off to the right and left by the pressure plates 35 and 41 and on its radially inner side by the control element 13 and on its radially outer side by the valve body 3.

[0027] The longitudinal section through the valve 1, as shown in the figure, illustrates how the first and second pressure plates 35 and 41 are arranged sealingly on their inner side facing the central axis 7 against the control element 13 and on their side radially away from the central axis 7 against the valve body 3: The control element 13 has a contact shoulder S1 against which the left outer surface of the end of the first pressure plate 35 facing the central axis 7 rests. The clamping element 37 rests against the right inner surface of the first pressure plate 35 facing the gap 43. This clamping element seals against the control element 13. The inner end of the second pressure plate 41 facing the central axis 7 rests against the end of the clamping element 37 opposite the first pressure plate 35, specifically its left surface facing the gap 43. A retaining or pressure element rests against the right side of the second pressure plate 41 opposite the gap 43, pressing the second pressure plate 41 against the clamping element 37, pressing the clamping element against the right side of the first pressure plate 35 facing the gap 43, and pressing the left side of the first pressure plate 35 against the contact shoulder S1.In this way, the inner sides of the pressure plates 35, 41, facing the central axis 7, are held tightly against the control element 13. The holding or pressure element can, for example, be designed as a separate retaining ring that is pushed or screwed onto the control element 13. In the embodiment shown here, an anchor 73 is attached to the control element 13, preferably by means of an internal thread that meshes with an external thread on the control element 13. By screwing the control element 13 and the anchor 73 together, the clamping forces are applied to the inner ends of the pressure plates 35, 41, with the clamping element 37 being arranged between the two pressure plates 35, 41.

[0028] The outer sides of the pressure plates 35 and 41, facing away from the central axis 7, are sealed to the valve body 3 in a corresponding manner. The valve body 3 has a contact shoulder S2 against which the left outer side of the first pressure plate 35 rests. The clamping element 39 mentioned above rests against its right inner side, which faces the space 43. The radially outer end of the second pressure plate 41, specifically its inner side facing the space 43, is pressed against the axially opposite end of the clamping element 39. A retaining or pressure element is also located on the opposite outer side of the second pressure plate 41. A clamping sleeve 44 is provided here, which is screwed into the valve body 3 and is ring-shaped, allowing the control element 13 and the armature 73 to pass through its free interior.The clamping sleeve 44 has an external thread which interacts with an internal thread in the valve body 3, so that the clamping sleeve 44 can be screwed into the valve body 3 in such a way that it exerts a force on the right outer side of the second pressure plate 41 and seals it against the clamping element 39. This exerts a force on the clamping element 39, which presses the outer end of the first pressure plate 35 against the mounting shoulder S2.

[0029] The space 43 is connected to the environment surrounding the valve body 3 via a venting device 45. This can be a bore through the clamping element 39 leading from the space 43 to the outside. An annular space 47 is provided outside the clamping element 39, which leads via a bore 49 into a venting chamber 51. This venting chamber is sealed off from the environment by a plug 52, which can have an integrated filter through which the medium in the space 43 can escape to the outside, while preventing dirt and / or moisture from entering the venting chamber 51 or the space 43.

[0030] It is crucial that the space 43 is vented, so that no pressure can build up here, while contamination of the space 43 should be avoided as much as possible.

[0031] If the control element 13 within the valve body 3 in the channel 5 is displaced to the right from the position shown in the figure along the central axis 7, the sealing element 15 is moved into its second functional position and pressed against the right-hand second valve seat 19, preferably with a specific pressure force, so that the fluid connection between the first fluid path 23 and the second fluid path 25 via the first fluid section 27 is interrupted. The sealing element 15 is thereby positioned at a distance from the first valve seat 17, so that a fluid connection between the first fluid path 23 and the third fluid path 29 is opened. In the embodiment shown in the figure, the control element 13 extends to the left into a region of the third fluid path 29, with its left end 53 preferably guided. The valve 1 can have a closing element 55 inserted into the valve body 3, into which the control element 13 projects.It should be noted here that the left end 53 of the control element 13 does not necessarily have to be guided. Furthermore, if guidance is desired, the left end 53 can be guided directly in the valve body 3, or, as shown here, by a closing element 55 inserted into the valve body 3, which has a channel section 57 that is preferably arranged concentrically to the central axis 7. This channel section 57 forms the third fluid path 29.

[0032] To establish a fluid connection between the first fluid path 23 and the third fluid path 29, the control element 13 is provided with a cavity 59 at least over a region of its longitudinal extent, i.e., in the direction of the central axis 7, which opens to the third fluid path 29 at the left end 53 of the control element 13. A bore 63 penetrating the cavity 59, thus creating a fluid connection between the first fluid path 23 and the third fluid path 29.

[0033] The bore 63 opens into a fluid chamber 65, which surrounds the control element 13 on the outside and is limited to the right by the sealing body 15 adjacent to the second valve seat 19.

[0034] The cavity 59 extends to the right in the direction of the central axis 7 so far that a fluid connection is created via at least one bore 67 from the cavity 59 to a pressure chamber 69 surrounding the control element 13, which in the figure is bounded to the left by the second pressure plate 41 and to the right by the valve body 3 of the valve 1.

[0035] Between the first fluid path 23 and the third fluid path 29, a second fluid section is formed by the fluid chamber 65, the bore 63, and the cavity 59, connecting the first and third fluid paths 23 and 29, respectively. Pressure in this second fluid section propagates to the right into the cavity 59, and through the at least one bore 67 into the pressure chamber 69, so that this pressure acts on the second pressure plate 41. The pressure acts on the right side of the second pressure plate 41 in the figure, while its left side defines the space 43.

[0036] A pressure prevailing in the fluid chamber 65 acts from the left on the sealing element 15, which abuts the second valve seat 19, and from the right on the right side of the second pressure plate 41. The pressure acting on the sealing element 15, which abuts the second valve seat 19, causes a force acting to the right on the control element 13, while a pressure acting on the right side of the second pressure plate 41 exerts a force acting to the left on the control element 13. The two forces acting on the sealing element 15 and the second pressure plate 41 are therefore opposite to each other. It is preferably provided that the effective area of ​​the second pressure plate 41 and that of the sealing element 15 are essentially equal, so that a substantially force-balanced state results.This ensures that the control element 13 can be moved from its right position, in which the sealing body 15 rests against the right second valve seat 19, to its left first functional position, in which the sealing body 15 rests against the left first valve seat 17, essentially without opposing pressure forces.

[0037] The valve 1 shown in the figure has a drive unit 71. This unit acts on the control element 13 such that the latter can be moved from the left position shown in the figure to its right position, in which the sealing element 15 rests against the second valve seat 19. The drive unit 71 can be designed so that the movement of the control element 13 in this direction can be carried out manually. Preferably, however, the drive unit 71 includes an electromagnet which, when activated, moves the control element 13 directly or via the armature 73.

[0038] When the actuator 71 is inactive, i.e., the electromagnet is not energized, the control element 13 or the armature 73 is not attracted and moved to the right, but is moved to the left by a preload element 75 until the sealing element 15 abuts the first valve seat 17 on the left, forming a seal. The preload element 75 can be an elastic, compressible plastic element or the like, preferably a spring, which is supported on one side by a stationary part of the actuator 71, for example, on a magnetic core 77, and on the other side by the control element 13 or the armature 73. The preload element 75 is designed such that, in the inactive state of the actuator 71, it presses the sealing element 15 against the first valve seat 17, thus creating a fluid connection between the first fluid path 23 and the second fluid path 25.

[0039] When the drive unit 71 is activated, a tensile force is exerted on the control element 13, possibly via the armature 73, causing the control element 13 to move to the right together with the sealing element 15. This lifts the sealing element 15 from the first valve seat 17 and places it against the second valve seat 19, sealing it in place.

[0040] The two pressure plates 35 and 41 are so elastic that they allow relative movement of the control element 13 with respect to the valve body 3 without being damaged and seal the space 43 regardless of the position of the control element 13.

[0041] The valve 1 shown in the figure is designed such that conventional connection elements for hoses or the like can be provided in the recesses in the valve body 3 that form the first, second, and third fluid paths 23, 25, and 29. The embodiment of the valve 1 shown here is, purely by way of example, a 3-way valve. It is essential that the valve has a control element 13 to which a sealing element 15 and two pressure plates 35 and 41 are attached, wherein the sealing element 15 and the pressure plates 35, 41 can be pressurized such that the forces introduced into the control element 13 are always opposite to each other, regardless of the operating position of the sealing element 15. In the first operating position shown in the figure, the sealing element 15 rests against the left valve seat 17. Forces act on it from right to left.This pressure also acts on the first pressure plate 35, generating pressure forces acting from left to right. Because the effective areas of the sealing element 15 and the first pressure plate 35 are essentially the same size, the opposing forces cancel each other out.

[0042] Accordingly, in the second operating position, which is not shown in the figure and in which the sealing element 15 rests against the right-hand, second valve seat 19, forces acting on the sealing element 15 from left to right and forces acting on the second pressure plate 41 from right to left are exerted. These opposing forces essentially cancel each other out because the effective surfaces of the sealing element 15 and the second pressure plate 41 are aligned so that they are essentially equal.

[0043] The valve 1 is in the functional position shown in the figure, in which the sealing element 15 rests against the first valve seat 17 on the left, in the inactive state, meaning that the actuator 71 exerts no force on the control element 13. Instead, the control element 13 is held in the position shown in the figure by the preload element 75. The valve 1 can remain in this position for a very long time. During this time, a medium in the channel 5 can, for example, diffuse from left to right through the first pressure plate 35 into the intermediate space 43, which is connected to the environment via a venting device 45. Therefore, it is not possible for pressure to build up on the side of the first pressure plate 35 facing the intermediate space 43 that would prevent the desired pressure equalization.

[0044] To activate valve 1 and move the sealing element 15 into its second position, where it rests against the second valve seat 19, the actuator 71 is activated, either manually or preferably by an electromagnet. In this case, a coil 76 of the electromagnet is energized, causing the magnetic core 77 to attract the control element 13, possibly via the armature 73, against the force of the preload element 75 and move it to the right from the position shown in the figure, so that the sealing element 15 rests against the second valve seat 19. Since a force-balanced state exists, the forces required to move the control element 13 are relatively small, as only the preload force of the preload element 75 needs to be overcome.

[0045] The valve 1 described here is used in conjunction with a consumer. In the inactive state of the actuator 71, the control element 13 is in the position shown in the figure, in which the sealing element 15 rests against the left first valve seat 17. A fluid connection is thus open between the first fluid path 23 and the second fluid path 25, so that a medium fed into the first fluid path 23 is directed via the first fluid section 27 to the second fluid path 25.

[0046] The medium introduced into the first fluid path 23 originates from a tank not shown in the figure, which provides medium for the consumer and is connected to the fluid path 23 via a suitable line not shown here.

[0047] In the event that tank emptying is necessary, for example during servicing of the consumer and / or the tank, the valve 1 must be switched from the first operating position shown in the figure by activating the actuator 71. If, as preferably provided, this actuator has an electromagnet, it is energized so that the control element 13 is moved to the right and the sealing element 15 is applied to the second valve seat 19. In this case, a fluid connection is established between the first fluid path 23 and the third fluid path 29, which now serves as the drain port. The contents of the tank can thus be drained, either into the environment or into a collection container.

[0048] In this functional position of the sealing element 15, no medium reaches the consumer.

[0049] Pressure equalization also takes place in the empty state, so that the control element 13 can easily be moved back to its first functional position.

[0050] When the valve 1 is used in conjunction with a consumer, for example in a vehicle where tank emptying is only rarely necessary, the consumer equipped with the valve 1 operates with very low levels of malfunction because switching problems due to diffusion of the medium through at least one of the pressure plates, in particular through the first pressure plate 35, cannot lead to a pressure increase, as explained above. Instead, any medium diffusing through the first pressure plate 35 enters the space 43 and from there, via the venting device 45, into the environment. It can be assumed that the amount of fluid released is so small that it does not cause any significant environmental pollution during operation of the consumer.

[0051] Considering the function of the valve 1 explained here, the following advantage arises: Due to the fact that the control element 13 is force-balanced with the two pressure plates 35 and 41 as well as with the sealing body 15, it is possible to realize large nominal diameters, i.e. a large cross-section of the channel 5 as well as the three fluid paths 23, 25 and 29 present in the embodiment shown here.

Claims

[1] Valve (1) with - a valve body (3) which ◯ a channel (5), ◯ a first fluid path (23), ◯ a second fluid path (25) and ◯ includes at least one third fluid path (29), as well as with - a control element (13) slidably mounted in the channel (5), which ◯ comprises at least one sealing body (15) connected to it, which interacts with a first and second valve seat (17,19), - wherein the control element (13) comprises a first pressure plate (35) fixedly connected to it and a second pressure plate (41) fixedly connected to it, wherein - between the first pressure plate (35) and the sealing body (15) abutting the first valve seat (17) a pressurized first fluid section (27) in fluid communication with the first and second fluid paths (23,25) can be delimited, wherein - between the second pressure plate (41) and the sealing body (15) abutting the second valve seat (19) a pressurized second fluid section in fluid communication with the first and third fluid paths (23, 29) can be delimited, and wherein - the first and second printing plates (35,41) on the control element (13) are arranged at a distance from each other, wherein - a space (43) is enclosed between the printing plates (35,41), which ◯ is in fluid communication with a venting device (45) that prevents pressure build-up in the intermediate space (43), wherein ◯ the pressure given in the first fluid section (27) acts on the side of the first pressure plate (35) which is facing away from the space (43), and wherein ◯ the pressure given in the second fluid section acts on the side of the second pressure plate (41) which is facing away from the space (43). - characterized by , that The pressure prevailing in the first fluid section (27) acts on the sealing body (15) on the one hand and on the first pressure plate (35) on the other hand in such a way that the pressure forces acting on the control element (13) are opposite, wherein the effective areas of the sealing body (15) and the first pressure plate (35) are chosen to be of the same size, so that the pressure forces acting on the control element (13) via the sealing body (15) and the first pressure plate (35) are balanced, and wherein The pressure prevailing in the second fluid section acts on the sealing body (15) on the one hand and on the second pressure plate (41) on the other hand in such a way that the pressure forces acting on the control element (13) are opposite, whereby the effective areas of the sealing body (15) and the second pressure plate (41) are chosen to be of the same size, so that the pressure forces acting on the control element (13) via the sealing body (15) and the pressure plate (41) are balanced. [2] Valve (1) according to claim 1, characterized by , that the control element (13) with the sealing body (15) - in a first functional position releases a fluid connection between the first and second fluid paths (23, 25) and, by contacting the sealing element (15) with the first valve seat (17), interrupts a fluid connection between the first and third fluid paths (23, 29), and - in a second functional position releases a fluid connection between the first and third fluid paths (23,29) and prevents a fluid connection between the first and second fluid paths (23,25) by contacting the sealing element (15) with the second valve seat (19). [3] Valve (1) according to any one of the preceding claims, characterized by , that in the valve body (3) there is a space (21), preferably an annular space, extending at least partially around the control element (13), which forms the first fluid section (27) between the first fluid path (23) and the second fluid path (25). [4] Valve (1) according to any one of the preceding claims, characterized by , that the second fluid section comprises a cavity (59) extending at least over a region of the longitudinal extent of the control element (13), which is in fluid communication on the one hand with a pressure chamber (69) arranged on the side of the second pressure plate (41) facing away from the cavity (59) extending from the intermediate space (43) and surrounding the control element (13), and on the other hand with a fluid chamber (65) surrounding the control element (13) and bounded by the sealing body (15) adjacent to the second valve seat. [5] Valve (1) according to any one of the preceding claims, characterized by , that - the valve (1) has a drive device (71) which is configured to axially displace the control element (13), wherein - the drive unit (71) is set up to bring the sealing body (15) into the first and / or the second operating position. [6] Valve (1) according to claim 5, characterized by , that the drive device (71) includes an electromagnet.

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