Combined valve for steam circuit and sil3 certified safety circuit consisting of a quick acting valve and a control valve

Abstract

The present invention relates to a combination valve for a steam circuit, comprising a quick-acting valve (2) and a control valve (3), wherein the quick-acting valve and the control valve are disposed in a common housing (4, 5); wherein the control valve is movable by an active drive unit (8), and the quick-acting valve is movable passively by steam.

Description

Technical Field

[0001] This invention relates to a combination valve of a quick-closing valve and a regulating valve for steam circuits (particularly steam circuits of steam turbines). Background Technology

[0002] For safe operation of steam turbines, a pre-stroke hydraulic quick-closing valve is typically used as the main shut-off valve between the boiler and the steam turbine. This valve closes within a fraction of a second and remains fully open during operation, only closing if the machine is intentionally shut down or malfunctions (e.g., during load shedding and simultaneous failure of the regulating system). Throttling valves are used as regulating valves, adjusting the inlet pressure and steam flow to the specified steam pressure and flow rate before the steam turbine blades. The most commonly used regulating valves are non-relief single-seat valves, whose high valve force allows them to operate in high-pressure oil systems of 100-160 bar. For very large steam flows, bulky and heavy valves are used, operating similarly in high-pressure oil systems or medium-pressure oil systems of 30-50 bar.

[0003] To improve efficiency, steam is typically supplied to the turbine through multiple exposed sections (usually 2 to 6, up to 10 sections). The steam flowing into each section is regulated by its own control valve. As the load increases, the control valves open steadily one after another, ensuring that under any load condition, some control valves are fully open, while only one is partially open. Therefore, throttling losses occur only at this partially open control valve, resulting in good overall efficiency.

[0004] It is known that combining a quick-closing valve and a regulating valve in a common valve body constitutes a combination valve. In practice, each of the two valves has its own active actuator. Because the actuators for the respective valve stems must be located on different sides of the body, this combination valve suffers from a valve structure extension exceeding several meters. Furthermore, pressure loss, high valve force, and vibration, particularly at the valve stem, as well as valve seal leakage are common problems during operation. Vibration at the valve stem can lead to damage to the valve stem, valve seat, and valve guide. This can cause steam leakage, requiring additional suction. Additionally, pressure loss can occur due to multiple deflections of steam within the body. Summary of the Invention

[0005] The object of the present invention is to provide a combination valve for steam circuits (particularly for steam circuits of steam turbines) that enables a compact and space-saving arrangement as well as an advantageous fluid mechanical design.

[0006] This objective is achieved by a combination valve for a steam circuit, comprising a quick-closing valve and a regulating valve, wherein the quick-closing valve and the regulating valve are housed in a common housing, the regulating valve being actuated by an active actuator, and the quick-closing valve being passively actuated by steam (especially main steam) in the steam circuit over its full stroke between an open and closed position. Advantageous embodiments and improvements of this combination valve are set forth in the following description.

[0007] It has been found that this offers an advantage in terms of the size of the combined valve. By driving two valve assemblies in this way, the control valve requires only one active actuator, while the active actuator for the quick-closing valve is unnecessary. Therefore, the combined valve can be implemented with a small footprint.

[0008] A steam-controlled quick-closing valve can be moved in a simple manner by a suitable control area where steam is present in the valve body, via a corresponding pressure difference. For this purpose, the quick-closing valve preferably has a control area on its front side that enables it to open, and a control area on its rear side that facilitates its closing.

[0009] In this regard, the steam-controlled quick-closing valve is preferably configured such that when the quick-closing valve is open, steam pressure exists only in the front control area, while there is no pressure in the rear control area. To close the quick-closing valve, steam pressure is applied to both control areas. Since the front and rear control areas provide approximately equal working areas for steam pressure, an additional (preferably mechanical) closing component (e.g., a spring) is installed for the closing operation of the quick-closing valve. When the quick-closing valve is closed, the closing component additionally acts on the rear control area, thereby achieving the closing operation of the quick-closing valve. Furthermore, in the absence of steam pressure, this mechanical closing component can keep the quick-closing valve closed.

[0010] The mechanical shut-off component is preferably selected such that it does not impede the opening of the quick-closing valve when a sufficiently high steam pressure exists in the front control zone and there is no pressure in the rear control zone. The shut-off force of this component is adjusted to be less than the force at the front control zone of the quick-closing valve exposed to steam pressure. The shut-off force of this mechanical shut-off component is less than 75%, particularly less than 50%, particularly less than 25%, particularly less than 10%, particularly less than 5%, and particularly less than 1% of the force required to close the valve due to the present steam pressure.

[0011] This combination valve features a control element that allows steam to be selectively directed to at least one downstream control zone of the fast-closing valve. This control element (e.g., the valve itself) is significantly smaller than the active actuator and can be positioned on the side or above the valve housing. The active actuator of the regulating valve is preferably precisely attached to one side of the housing.

[0012] This compact design allows for a simple and space-saving arrangement of the combined valve in the steam circuit. Furthermore, the small size of the combined valve itself saves space.

[0013] In this combined valve, the stem sealing to the atmosphere is advantageously achieved by the following method: the quick-closing valve has no stem, only the regulating valve has an outward-facing stem, and the control area behind the quick-closing valve is pressureless when it is in the open position. Therefore, the regulating valve's stem seal seals the stem to the atmosphere on one side and can remain pressureless on the other side during operation. The regulating valve's stem seal is only temporarily under static pressure when the steam pressure to the steam turbine is activated, but only before the opening operation of the quick-closing valve begins.

[0014] Preferably, the quick-closing valve is configured with a sleeve-shaped quick-closing valve body. On one hand, the sleeve-shaped valve body allows the valve to close safely. On the other hand, such an embodiment has a uniform front working area for steam. The back of the sleeve-shaped quick-closing valve body is preferably designed as a circular area. Furthermore, the sleeve-shaped embodiment of the quick-closing valve body allows for the arrangement of more components within the internal space of the quick-closing valve body.

[0015] Therefore, advantageously, the control valve can be configured to have a tubular valve body, and this tubular valve body can be guided inside the sleeve-shaped quick-closing valve body. This allows the control valve to be at least partially located within the internal space of the quick-closing valve. This means that the two valve bodies together require only slightly more space than a single valve body. Furthermore, the fact that the two movable valve bodies move in the same direction away from their corresponding valve seats allows steam to flow in and out freely with low flow loss.

[0016] Preferably, the control valve is implemented as a "pressure-relief tubular control valve." This achieves pressure-relief actuation of the control valve. The tubular valve body is a pipe segment having two annular sealing regions and preferably an inner wall to which the valve stem shaft, connected to the actuator of the control valve, is fastened. Furthermore, the inner wall preferably has an orifice for pressure relief of the control valve. Due to the orifice, only a minimal pressure needs to be counteracted during the stroke of the control valve.

[0017] Alternatively, the control valve can be implemented as a "pre-stroke control valve", wherein the pre-stroke on the control valve opens first, followed by the valve body opening.

[0018] Just as the tubular valve body of a control valve can be advantageously guided inside the sleeve-shaped quick-closing valve body, the sleeve-shaped valve body of a quick-closing valve can then be advantageously guided to the outside of a guide sleeve. This guide sleeve can be a separate element within the housing, or the housing itself can be internally configured as a guide sleeve for the sleeve-shaped valve body of the quick-closing valve.

[0019] Preferably, in the sense of two independent, redundant shut-off elements, the combined valve allows for independent switching and closing of the two components (i.e., the regulating valve and the quick-closing valve). For example, the regulating valve can initially remain closed, while the quick-closing valve can be opened. Then, when steam needs to be allowed to pass through, the regulating valve can be opened. This also gives it good adjustability for small steam flow rates.

[0020] A preferred embodiment of the combined valve with two independent, redundant shut-off elements also enables the rapid and safe cessation of the steam supply. For example, the steam supply to the steam turbine through this combined valve must be completely shut off within approximately 0.3 seconds to ensure the protection of the steam turbine. Because both valves achieve these shut-off times, it is sufficient for one of the two valves to shut off the steam flow without leakage. Preferably, both valves shut off without leakage. In particular, the quick-closing valve shuts off without leakage. Although the regulating valve may have leakage flow, the leakage flow of the regulating valve can preferably be as low as negligible. In particular, in cases where steam is supplied to the turbine through several exposed sections and thus multiple combined valves are provided, the leakage flow of the regulating valve is not a problem, as it always directly affects only the first / next valve to open in the combined valve bank (especially the regulating valve). In any case, since the other valves (especially the quick-closing valve) have been closed first, there is no leakage. Compared to the prior art, this combined valve has the advantage that multiple leakage flows do not accumulate. This situation can be reliably prevented using the combined valve of the present invention.

[0021] More preferably, a switchable control valve is provided for switching the quick-closing valve. A 3 / 2-way valve is specifically used for this purpose. This switchable control valve serves to direct steam through the piping system to the rear side of the quick-closing valve body. This valve has the necessary switching time to close the quick-closing valve in approximately 0.3 seconds. Furthermore, the switchable control valve can be configured with a relatively small and inexpensive actuator.

[0022] Preferably, the control valve has a hydraulically or pneumatically actuated control actuator. This allows for directional switching of the combination valve via the control actuator used. The preferred drive mechanism for the control actuator is chosen such that it does not require a complex actuator but can be implemented in a small size relative to the combination valve. This allows the valve including the aforementioned control actuator to be positioned to the side or above the combination valve. Hydraulics or pneumatics are generally already present in the application areas of such combination valves and can be used directly.

[0023] The control valve can advantageously have a control valve actuator implemented as a low-pressure hydraulic actuator or an electric actuator. This allows for directional control of the control valve. Furthermore, the preferred actuator is easy to operate. The preferred design of the control valve as a pressure-relief tubular control valve allows the use of low-pressure hydraulic devices in the range of 2 to 18 bar, particularly 4 to 16 bar, particularly 6 to 14 bar, particularly 8 to 12 bar, instead of the high-pressure hydraulic devices of 60 to 200 bar typically used for non-pressure-relief valves, or electric actuators. Because only small torque is required, the electric actuator for the pressure-relief control valve can be implemented in a relatively small size.

[0024] Advantageously, the housing of the combination valve consists of a housing base and a housing cover, the housing base being connected to the housing cover by force fit and / or form fit. This achieves uncomplicated installation of the components and also relatively uncomplicated replacement of the installed components. The housing cover is preferably connected to the housing base by screws. The housing cover preferably precisely includes one sidewall of the housing.

[0025] The actuators for the quick-closing valve and the regulating valve, as well as the quick-closing valve itself and the regulating valve itself, are preferably fastened to or guided onto the housing cover. This allows for easy disassembly of the valve and its actuator by removing the housing cover, thereby facilitating easy replacement of components in a more suitable location (e.g., in the workshop). Preferably, the actuator can also be removed separately while the housing cover is installed. This allows for easy and quick replacement of defective actuators.

[0026] If a component is defective, including the entire cover of the valve mechanism, it can be replaced without disassembling the piping connections. Replacing the entire housing cover allows for short downtime of the combination valve. The defective housing cover can then be repaired or replaced, while the steam circuit can be further operated with the replaced cover.

[0027] The housing preferably has a steam filter at the steam inlet, which includes a steam deflector, enabling partial deflection of the incoming steam flow. With this type of valve, the steam flow must be guided through a 90° angle, which would result in flow losses. Due to the use of the steam filter, the incoming steam is already deflected at the steam inlet by 10° to 80°, particularly 25° to 65°, particularly 30° to 55°, particularly 40° to 50°, and particularly 45°. This partial deflection reduces flow losses occurring in the valve by gradually deflecting the steam.

[0028] Steam filters also allow for the removal of foreign objects entrained in the steam flow. These foreign objects include, for example, welding beads or debris from the boiler and piping. By removing entrained foreign objects, damage to the valve body, valve area, and turbine blades from foreign object impacts is prevented. Damage to the valve body and valve area can lead to undesirable fluid leaks. Damage to the turbine blades can reduce turbine efficiency, although this does not necessarily lead to turbine shutdown. In extreme cases, this can lead to blade breakage, additional damage to internal turbine components, and even damage to the turbine casing, all of which can cause turbine shutdown and often make subsequent maintenance unavoidable.

[0029] The steam filter is preferably detachably connected to the housing cover. This allows for easy cleaning and replacement of the steam filter. The steam filter can be removed by removing it along with the cover. The connection between the steam filter and the cover (preferably implemented as a pin connection) can be disassembled, and the steam filter can be inspected, cleaned, and / or replaced. This allows for easy and quick replacement of the steam filter in the event of damage or severe contamination. Foreign matter entrained in the steam flow or vibrations caused by the steam flow can damage the steam filter.

[0030] Furthermore, the steam filter can preferably rest against the assembly guides of the housing base in the installed state for stability, thereby minimizing mechanical loads on the steam filter, such as vibrations caused by steam. The guides in the housing base are preferably designed so that the steam filter will not be damaged by slight vibrations within the guides. For this purpose, the guides preferably have inserts made of a soft and therefore cushioned material.

[0031] The housing also advantageously features a diffuser at the steam outlet. This allows for further reduction of flow losses in the combined valve. The diffuser here advantageously serves as the sealing area for both the quick-closing valve and the regulating valve. The sealing area of ​​the quick-closing valve is located radially outward relative to the sealing area of ​​the regulating valve.

[0032] Preferably, the diffuser has a vortex-breaking device that acts as a deflector of the steam flow and dissipates turbulence in the steam flow. This vortex-breaking device is made of 2 to 12, particularly 4 to 8, particularly 5 to 7, particularly 6 vortex-breaking teeth. The vortex-breaking teeth are located on the inlet side of the diffuser and extend into the interior space of the flow channel. In this way, they can prevent or eliminate turbulence in the steam flow.

[0033] Particularly preferably, the eddy current breaking teeth of the eddy current breaking device are located between the sealing seat of the quick-closing valve and the sealing seat of the regulating valve. Therefore, this eddy current breaking device can act as a guide for the regulating valve. This means that in the final region of the regulating valve stroke, shortly before the regulating valve reaches the sealing seat at the diffuser, the guide of the eddy current breaking device intervenes. Preferably, the guide intervenes approximately up to the first third of the stroke when the regulating valve leaves the sealing seat on the diffuser, and similarly, when closing, before the regulating valve reaches the last third of the sealing seat. This allows for minimizing vibrations of the regulating valve in this region, which are most intense when the regulating valve is open.

[0034] The diffuser is advantageously housed in a removable manner within the housing base. This allows for easy replacement of the diffuser in case of valve maintenance or diffuser damage (e.g., damage to the sealing area). For example, the diffuser can be screwed into the housing base or inserted and secured via a pin or threaded connection.

[0035] As mentioned earlier, the diffuser serves as the sealing area for control valves and quick-closing valves. Because the rapid closing process can damage these areas, easy replacement of the diffuser is useful and can therefore minimize maintenance work.

[0036] Here, to facilitate and improve the inspection of wear and / or damage, the diffuser can be inspected from the outside of the housing. On one hand, inspection in the disassembled state allows for improved visual inspection of all areas of the diffuser. On the other hand, inspection in the disassembled state allows for the use of different inspection methods, such as various types of radiographic inspection or surface inspection.

[0037] It is common for steam circuits to operate for months or even years without the quick-closing valve needing to be closed. Therefore, it is particularly important for steam circuits to demonstrate that the quick-closing valve does indeed move and does not jam when suddenly needed. The corresponding tests are performed during continuous operation and must not interfere with operation. This is not difficult in systems with two redundant quick-closing valves installed in parallel, as each quick-closing valve can be closed individually for testing purposes, while the other remains open to ensure steam flow. However, if only one quick-closing valve is installed, for example, because redundancy is ensured by a regulating valve (as in this combination valve), a so-called partial stroke test is performed on the quick-closing valve, characterized by the quick-closing valve moving only a portion of its stroke without affecting the continuous, regulated, and reduced operation of the steam circuit. This test is standardized by the American API 612 standard. In this combination valve, the stroke range of the quick-closing valve in the partial stroke test is preferably 15% to 20% of the full stroke.

[0038] For this purpose, the quick-closing valve is exposed to main steam via a separate shut-off line, allowing it to move in its closing direction (e.g., supported by the spring force of a mechanical shut-off component) during continuous operation of the steam circuit. Due to this movement in the closing direction, a throttling point opens, through which main steam can escape, preventing further movement of the quick-closing valve in the closing direction and causing it to remain in a partial stroke position. The success of the partial stroke test is checked by two pressure sensors positioned upstream and downstream of the throttling point. The test is confirmed successful when both pressure sensors indicate that the pressure has stabilized at a common average between the pressure at the steam inlet and the ambient pressure.

[0039] Of course, full-stroke testing provides more information, as it also provides information about the valve's closing capability. Since steam is typically supplied to the turbine through several exposed sections, and therefore multiple combination valves are installed, partial-stroke testing of the quick-closing valves can advantageously replace a common full-stroke test of the regulating valves of both the quick-closing valves and the corresponding combination valves. For this purpose, the turbine output in the steam circuit is first reduced to accommodate the remaining open valves, allowing the combination valves to be tested full-stroke one after another, thus proving their suitability for safer turbine shutdown or closure.

[0040] The combination valves disclosed herein have a particular advantage: they can be used in safety circuits certified as "SIL 3" according to IEC / EN 61511 / 61508. "SIL" stands for "Safety Integrity Level," which specifies the requirements for the reliability of safety functions in electrical and / or electronic and / or programmable electronic systems at four safety levels. SIL means that the harm to people, the environment, and property has been reduced to an acceptable level. For example, a safety circuit with only one quick-closing valve in a steam circuit cannot exceed SIL 2. For SIL 3, at least redundancy of the quick-closing valve is required, i.e., there must be a second upstream or downstream quick-closing valve, so that if one valve fails, at least another valve can still be closed. Two gate valves of the same type are called homogeneous redundancy. When the two gate valves are of different types, i.e., when a system failure will not cause both valves to fail simultaneously, this is called diversity redundancy. Redundanz). For example, a quick-closing valve (such as the quick-closing valve in this invention) is steam-controlled, and a regulating valve (on the one hand, suitable for completely closing the passage; on the other hand, for example, it is electrically actuated) can together enable the safety system to have SIL 3 capability (SIL 3). This combination valve integrates a quick-closing valve and a regulating valve into a common housing, and the fact that these two valves can be opened and closed independently of each other makes the combination valve compliant with SIL 3 capability (SIL) with versatility redundancy. MIT (Redundanz). Therefore, this combination valve can replace traditional quick-closing valves when SIL 3 requirements are met in a safety circuit. It has particular advantages, including a small size due to the two valves being combined into a single housing, and the ability to perform partial-stroke testing, a mandatory requirement of API 612. The combination of these two attributes in a single valve, along with SIL 3 capability, represents a significant technological advancement.

[0041] The features described in the above embodiments, and the features indicated in the following examples of the combined valve, are suited for further development purposes, individually or in combination with each other. The corresponding combinations of features do not represent limitations on further development of the combined valve, and are merely exemplary in their own characteristics. Attached Figure Description

[0042] Further embodiments will be explained in more detail below with reference to the accompanying drawings, in which:

[0043] Figure 1 A cross-sectional view of a first embodiment of the combined valve is shown, wherein both the quick-closing valve and the regulating valve are in the closed state;

[0044] Figure 2 It shows the relationship with Figure 1 The corresponding cross-sectional view of the combined valve shows that the quick-closing valve is in the open state and the regulating valve is in the closed state.

[0045] Figure 3 It shows the relationship with Figure 1 The corresponding cross-sectional view of the combined valve shows that both the quick-closing valve and the regulating valve are in the open state;

[0046] Figure 4 It shows the relationship with Figure 1 The corresponding cross-sectional view of the combined valve shows that the quick-closing valve is in a partial stroke test and the regulating valve is in the open state.

[0047] Figure 5 A front view of the diffuser is shown;

[0048] Figure 6 A cross-sectional view of a second embodiment of the combined valve is shown, wherein both the quick-closing valve and the regulating valve are in the closed state; and

[0049] Figure 7A side view of a spring sleeve with an axial groove located on the valve stem shaft of a control valve, and an associated tensioner, is shown. Detailed Implementation

[0050] Figure 1 A combination valve 1 is shown, wherein both the quick-closing valve 2 and the regulating valve 3 are in the closed state. The quick-closing valve 2 and the regulating valve 3 are coaxially arranged along the longitudinal axis 3a. The combination valve 1 includes a housing base 4 with a sleeve 60 and a housing cover 5. The sleeve 60 is inserted into the housing cover 5 and axially supported thereon. The housing base 4 and the housing cover 5 are interconnected by a threaded connection 6. In addition, the threaded connection 6 connects the valve accessory 7 and the housing cover 5 to the housing base 4. The regulating valve actuator 8 is screwed to the valve accessory 7. Alternatively, the valve accessory 7 can also be connected to the regulating valve actuator 8 by a pin connection, a welded connection, or a form-fit connection.

[0051] The regulating valve 3 is implemented as a pressure-relieving tubular regulating valve and includes a tubular valve body 64, a valve stem shaft 10, and a regulating valve actuator 8. The valve stem shaft 10 is connected to the regulating valve actuator 8 via a connecting rod 11. The tubular valve body 64 includes a labyrinth seal 12 and a sealing ring 13 on its exterior. The tubular valve body 64 also includes an inner wall 14 having a central valve stem shaft bore 15 and pressure relief holes 16 arranged circularly around the former. The number of pressure relief holes 16 is designed such that they provide sufficient pressure flow area so that the regulating valve 3 only needs to compensate for a minimum pressure difference when closed. Preferably, four, six, or eight pressure relief holes 16 are used. A larger or smaller number of pressure relief holes 16 is possible depending on their diameter.

[0052] The valve stem 10 is guided through the valve stem bore 15 and welded to the inner wall 14. The valve stem 10 is guided by the valve stem seal 17. The valve stem seal 17 is disposed in the housing cover 5 and is axially fixed along the longitudinal axis 3a by a tensioner 18.

[0053] The inner diameter of the sleeve 60 is larger than the outer diameter of the valve stem shaft 10. An annular gap (specifically, a clearance region) is formed between the valve stem shaft 10 and the sleeve 60, making it possible to achieve pressure balance through this gap.

[0054] The quick-closing valve 2 includes a quick-closing valve body 19, a first cylindrical compression spring 20, a second cylindrical compression spring 21, a spring sleeve 21a with an axial groove 63, a bushing 24, and a tensioner 22. The bushing 24 is connected to the quick-closing valve body 19 in a form-fit manner and serves as a guide on the valve stem shaft 10 of the regulating valve 3.

[0055] Tensioner 22 engages with the self-locking fine-pitch thread in the quick-closing valve body 19 according to the longitudinal dimension to be adjusted, thereby abutting against the edge of the quick-closing valve body 19 with a gap (e.g., 0.2 mm gap toward the bushing 24). Tensioner 22 has a hexagonal head and can be additionally secured with a pin. Furthermore, tensioner 22 is equipped with a sealing ring 23 that seals the internal space 59 of the spring chamber 32 in both directions along the movable valve stem shaft 10.

[0056] The quick-closing valve 2 includes a main steam passage 25, a control valve 26, a control line 27, a chamber 28, a shut-off line 29, and a shut-off valve 30. The shut-off valve 30 is connected to a spring chamber 32 via a port 31. The spring chamber 32 is connected to chamber 28 via eight ports 33. The number of ports 33 is not limited to eight. During the design phase, the number and diameter of the ports 33 should be selected such that the total area of ​​all ports 33 corresponds to the area of ​​the main steam passage 25.

[0057] The annular gap between the valve stem shaft 10 and the sleeve 60 is connected to the chamber 28 through at least one (particularly, multiple) radial holes 60a. When the quick-closing valve 2 is opened, once the tensioner 22 reaches the buffer zone, the steam pressure from the spring chamber can be reduced through the annular gap and the radial holes 60a.

[0058] Steam chamber 34 is connected to control valve 26 via main steam passage 25. When control valve 26 is deactivated, main steam passage 25 is connected to control line 27. Control line 27 terminates in chamber 28, which is connected to spring chamber 32 via orifice 33. Therefore, when control valve 26 is deactivated, main steam can enter spring chamber 32 through main steam passage 25, control line 27, chamber 28, and orifice 33, keeping the quick-closing valve in the "closed" position.

[0059] Control valve 26 includes a control actuator 35 and a 3 / 2-way valve 36, which includes a valve body 37 specifically implemented as a valve cone. Furthermore, control valve 26 includes a passage 38 connected to leakage steam line 40 via a shut-off valve 39. From the activated state of control valve 26, control line 27 is fluidly connected to either main steam passage 25 or passage 38.

[0060] The combination valve 1 includes a guide sleeve 41 connected to the housing cover 5, wherein the guide sleeve 41 is connected to the housing cover via a pin connection 42. The guide sleeve 41 is used to guide the quick-closing valve body 19. A sealing ring 43 is provided between the guide sleeve 41 and the quick-closing valve body 19, which seals the steam chamber 34 relative to the spring chamber 32.

[0061] The combination valve 1 includes a steam filter 44 with a steam deflection device 45. The steam filter 44 is connected to the housing cover 5 via a pin connection 46. Furthermore, the steam filter 44 is placed in a groove 47 in the housing base 4.

[0062] Furthermore, a diffuser 49 is disposed at the steam outlet 48 in the housing base 4. The diffuser 49 is connected to the housing base 4 by a retaining pin 50.

[0063] The diffuser 49 has a first sealing region 51 and a second sealing region 52. The first sealing region 51 serves as the seat of a quick-closing valve. The second sealing region 52 serves as the seat of a regulating valve 3. Furthermore, the diffuser 49 has an eddy current breaking device 53. This eddy current breaking device 53 has six eddy current breaking teeth 54, which are evenly distributed on the circumference of the diffuser 49.

[0064] The following will explain the function of combination valve 1 with reference to various switching states.

[0065] exist Figure 1 In this process, steam enters the combination valve 1 through steam inlet 55. The steam then appears at the control edge 56 of the quick-closing valve 2. Furthermore, steam guided through the main steam passage 25, control line 27, chamber 28, and orifice 33 appears at the rear of the quick-closing valve body 19. Because the rear of the quick-closing valve body 19 has a larger control area than the control edge 56, the quick-closing valve 2 remains closed due to the resulting force difference.

[0066] The regulating valve 3 is in the closed state. The first sealing area 51 and the second sealing area 52 prevent steam from entering the steam discharge port 48.

[0067] Figure 2 The combination valve 1 is shown, wherein the quick-closing valve 2 is in the open state and the regulating valve 3 is in the closed state. For this purpose, the valve body 37 of the control valve 26 travels from the first end position 57 to the second end position 58. The valve body 37 thus seals the main steam passage 25 and releases passage 38; however, passage 38 is currently still closed by the shut-off valve 39 toward the leakage steam line 40. The shut-off valve 39 opens slowly via a ramp, allowing steam from the spring chamber 32 to escape through the orifice 33, chamber 28, control line 27, 3 / 2-way valve 36, passage 38, and through the leakage steam line 40.

[0068] The quick-closing valve 2 is slightly raised due to the steam pressure at its control edge 56, and once the entire front side of the quick-closing valve body 19 is pressurized, it moves backward into the spring chamber 32 and is opened. The quick-closing valve 2 moves backward until the spring sleeve 21a, supported by the elastic force of the cylindrical compression spring 21, covers the orifice 33, thus interrupting the steam flow to the leaking steam pipe 40.

[0069] The quick-closing valve 2 has now reached the buffer zone, and the pressure enclosed in the spring chamber 32 will then decrease slowly only through the gap until the tensioner 22 reaches its contact diameter D. k The spring chamber 32 is sealed against the sleeve 60. The opening process of the quick-closing valve is now complete and is confirmed by the pressure measuring device PT61 in the control line 27 and the pressure measuring device PT62 in the spring chamber 32, both of which should indicate the ambient pressure.

[0070] The regulating valve 3 further prevents main steam from entering the steam discharge port 48 through the second sealing zone 52. Depending on the implementation of the regulating valve 3 and the diffuser 49, the regulating valve 3 may completely seal or allow a certain amount of leakage steam flow through the second sealing zone 52.

[0071] Figure 3 A combination valve is shown, in which both the quick-closing valve 2 and the regulating valve 3 are in the open state. At this time, the main steam is guided from the steam inlet 55 through the steam filter 44. The steam deflector 45 of the steam filter 44 deflects the steam flow at an angle α = 45° in the direction of the steam outlet 48.

[0072] The steam deflector 45 minimizes flow losses in the steam flow, which can occur if the deflection is too strong. The steam flow passes through the steam chamber 34 in the direction of the steam outlet 48. The vortex-breaking teeth 54 of the vortex-breaking device 53 in the diffuser 49 prevent turbulence in the steam flow and thus further reduce steam flow losses. Furthermore, the additional guidance of the regulating valve 3 in the vortex-breaking device 53 reduces vibrations.

[0073] according to Figure 3 The combined valve 1, with both the quick-closing valve and the regulating valve open, must completely shut off the steam supply within a very short time (specifically, approximately 0.3 seconds) to protect or shut down the turbine. For this purpose, the control actuator 35 is deactivated by a quick-closing command, and the valve body 37 travels from its second end position 58 to its first end position 57, as... Figure 1 As shown in the diagram. Therefore, valve body 37 seals passage 38 and releases main steam passage 25, thereby allowing steam to enter control line 27 and chamber 28 through 3 / 2-way valve 36 until it reaches orifice 33.

[0074] Because the spring chamber 32 is initially unpressurized, the steam force present in the orifice 33 will cause the spring sleeve 21a to overcome the relatively small elastic force of the cylindrical compression spring 21 and move in the closing direction, thereby opening the flow into the spring chamber 32. Simultaneously, the entire rear side of the quick-closing valve body 19 is pressurized to the contact diameter of the tensioner 22 on the sleeve 60.

[0075] The steam impulse and steam pressure acting on the rear side of the quick-closing valve body 19, together with the mechanical closing force of the cylindrical compression spring 20, cause the tensioner 22 to disengage from the sleeve 60, thereby equalizing the steam pressure on the front and rear sides of the quick-closing valve body 19, allowing the quick-closing operation on the quick-closing valve 2 to be performed by movement along the longitudinal axial direction 3a. The quick-closing valve 2 has now returned to its position as follows: Figure 1 The initial position is shown, achieved by sealing the sealing area 51 on the diffuser 49 and cutting off further steam flow into the turbine. The shutdown operation is complete and confirmed by two pressure measuring devices PT61 and PT62, both of which should indicate the steam pressure in the steam inlet 55.

[0076] Control valve 3, as a redundant version of quick-closing valve 2, also receives a quick-closing command. Actuator 8 moves control valve 3 along longitudinal axis 3a via connecting rod 11 and valve stem shaft 10 until it closes and seals diffuser 49 through sealing region 52, thereby safely preventing any steam from flowing into the turbine. Because both valves (i.e., quick-closing valve 2 and control valve 3) are now closed, the desired steam flow is achieved according to… Figure 1 The initial position.

[0077] Figure 4 This illustrates that during a partial stroke test, the quick-closing valve 2 and the regulating valve 3 of the combination valve 1 are in the open state. For the partial stroke test, the shut-off valve 30 is slowly opened via a ramp during continuous operation, meaning the regulating valve 3 is in the open state. From Figure 3 Starting from the position shown, the main steam and main steam pressure can now reach the spring chamber 32 through the main steam passage 25, the shut-off pipe 29, the shut-off valve 30, and the orifice 31, and further reach the contact diameter D of the tensioner 22 resting on the sleeve 60 through the axial groove 63 of the spring sleeve 21a. k As a result, due to the main steam pressure acting on the rear side, the quick-closing valve 2, being in the open state, has a component force in the closing direction. Together with the elastic force of the mechanical closing components 20 and 21 acting in the closing direction of the quick-closing valve, the quick-closing valve 2 overcomes the steam pressure acting on the entire front side of the quick-closing valve body 19, and can therefore move out of its position and towards the closing direction. The mechanical closing component 20 is designed not only to overcome the steam pressure difference between the front and rear sides of the quick-closing valve body 19, but also to have a sufficient closing force of approximately three times the mass of the quick-closing valve body 19.

[0078] Supported by the closing force of mechanical closing components 20 and 21 up to the contact diameter D of tensioner 22. kThe steam thus moves along the longitudinal axis 3a toward its closed position, quickly closing the valve 2. This lifts the tensioner 22 away from the sleeve 60. The spring sleeve 21a, supported by the elasticity of the cylindrical compression spring 21, first continues to seal the orifice 33, and the tensioner 22 is now also fully exposed to pressure through the axial groove 63.

[0079] After a defined and adjustable stroke, the tensioner 22 impacts the spring sleeve 21a and moves it coaxially along the longitudinal axis 3a. This means that the orifice 33 is no longer covered by the spring sleeve 21a, allowing steam to escape through the orifice 33, chamber 28, control line 27, 3 / 2-way valve 36, and passage 38 into the leaking steam line 40. This creates force balance and static pressure in the spring chamber 32, which moves the quick-closing valve to a partial stroke test position at approximately 15% to 20% of the full stroke and holds it there.

[0080] The partial stroke test is checked and confirmed to be successful by measuring the pressure displayed by two pressure sensors, PT61 and PT62, respectively positioned upstream and downstream of the throttling point, in each case, stabilizing at a common average between the steam pressure at steam inlet 55 and the ambient pressure. Then, the shut-off valve 30 closes again. The pressure from the spring chamber 32 is subsequently reduced to the leaking steam line 40 through orifice 33, chamber 28, control line 27, 3 / 2-way valve 36, and passage 38. Simultaneously, the steam pressure across the entire front side of the quick-closing valve body 19 moves the quick-closing valve 2 backward into the spring chamber 32 until the spring sleeve 21a covers the orifice 33 and interrupts the steam flow to the leaking steam line 40.

[0081] During the opening of the quick-closing valve 2, the buffer zone is also reached. The pressure enclosed in the spring chamber 32 will then decrease slowly only through the gap until the tensioner 22 reaches its contact diameter D. k It rests against the sleeve 60 and seals the spring chamber 32. The quick-closing valve 2 now returns to the "open" position.

[0082] Figure 5 A front view of diffuser 49 is shown. The vortex-breaking teeth 54 here, due to their uniform arrangement and shape, prevent the formation of vortices in the steam flow as it enters diffuser 49. The steam flow here is separated by the vortex-breaking teeth 54 at the boundary of diffuser 49. These separated steam flows therefore cannot form large steam vortices and re-merge after the vortex-breaking teeth, thus forming a directional steam flow.

[0083] Figure 6A second embodiment of the combination valve 1 is shown. This second embodiment differs from the first embodiment in the design and operating mode of the regulating valve 3. Except for the sealing ring 13, which is omitted here, all other reference numerals remain consistent with their respective functions and positions in the accompanying drawings. Figures 1 to 4 The same as in the first embodiment example. The regulating valve actuator 8 and valve stem shaft 10 also substantially correspond to the first embodiment example in their embodiments.

[0084] In the second embodiment example, the regulating valve 3 is implemented as a pre-stroke regulating valve. Here, the regulating valve 3 includes a tubular valve body 64, a pusher 66, a puller 67, and a tensioner 68, wherein the tubular valve body 64 has a step 65 disposed on the inner side of the tubular valve body 64. The pusher 66 has a central hole 69. The puller 67 has a pressure relief hole 70.

[0085] The tubular valve body 64 is guided inside the quick-closing valve body 19. The sealing ring 13 is omitted, thus the labyrinth seal 12 now allows a small amount of steam to reach the stepped body 72 and ensures its function. The pusher 66 abuts against the step 65 within the tubular valve body 64. The pusher 66 abuts against the puller 67. The tensioner 68 abuts against the puller 67 and secures the positions of the pusher 66 and the puller 67. The puller 67 is guided on the valve stem shaft 10 through the central hole 71.

[0086] To open the regulating valve 3, the valve stem shaft 10 moves backward via the regulating valve actuator 8. At this time, the stepped body 72 of the valve stem shaft 10 abuts against the pulling body 67 after a short stroke, and moves the tubular valve body 64 via the pulling body 67 and the tensioner 68.

[0087] To close the regulating valve 3, the valve stem 10 travels forward via the regulating valve actuator 8. At this time, the stepped body 72 of the valve stem 10 abuts against the pusher 66 after a short stroke. The valve stem 10 then moves the tubular valve body 64 forward to the closed position via force transmitted through the pusher 66 and the step 65. In the closed position, the tubular valve body 64 abuts against the second sealing region 52 of the diffuser 49.

[0088] Because such pre-stroke regulating valves have existed since the 1960s, and are described in, for example, Traupel, W.: "Thermische Turbomaschinen", Springer-Verlag, 1982, and are known to those skilled in the art, a detailed explanation is omitted here. However, it should be clear that this also applies to valves with... Figure 6 The diagram shows different pre-stroke control valves with varying structures.

[0089] Figure 7A side view of the spring sleeve 21a and tensioner 22 is shown. The tensioner 22 is implemented as an external hexagon on one end face. This external hexagon has a side distance corresponding to a standard wrench size. The surface of the external hexagon of the tensioner 22 is raised. This protrusion is at the contact diameter D. k Preferably, it has a linear maximum value.

[0090] The spring sleeve 21a has four axial grooves 63. The axial grooves 63 are evenly distributed on the circumference of the inner hole of the spring sleeve 21a. The tensioner 22 is disposed in the inner hole of the spring sleeve 21a. The tensioner 22 rests flat against the spring sleeve.

[0091] Axial grooves 63 serve as flow channels and allow pressure equalization during the opening and closing of the quick-closing valve. Due to the hexagonal geometry and the 90° offset arrangement of the axial grooves 63, the wrench head design of the hexagonal tensioner 22, and the number of axial grooves, at least one flow channel is at least partially exposed. Pressure differentials that cannot be balanced through the flow channels may cause errors during the opening and / or closing of the quick-closing valve, negatively impacting the function of the combination valve.

[0092] List of reference numerals

[0093] 1. Combination valve

[0094] 2. Quick-closing valve

[0095] 3. Control valve

[0096] 3a Longitudinal axis

[0097] 4. Shell base

[0098] 5. Housing cover

[0099] 6. Threaded connection

[0100] 7 Valve Accessories

[0101] 8. Control valve actuator

[0102] 10 Valve stem shaft

[0103] 11 Connecting rod

[0104] 12 Labyrinth Seals

[0105] 13 Sealing ring

[0106] 14 Inner Wall

[0107] 15 Valve stem shaft hole

[0108] 16 pressure relief holes

[0109] 17 Valve stem seal

[0110] 18 tensioners

[0111] 19. Quick-closing valve body

[0112] 20 Cylindrical compression springs

[0113] 21 Cylindrical compression spring

[0114] 21a Spring Sleeve

[0115] 22 tensioners

[0116] 23 Sealing ring

[0117] 24 bushings

[0118] 25 Main Steam Passage

[0119] 26 Control valve

[0120] 27 Control lines

[0121] 28 chambers

[0122] 29 Cut-off pipeline

[0123] 30 Stop valve

[0124] 31 holes

[0125] 32 Spring Chamber

[0126] 33 holes

[0127] 34 Steam Chamber

[0128] 35 Control Driver

[0129] 36 3 / 2-way valve

[0130] 37 Valve body

[0131] 38 channels

[0132] 39. Stop valve

[0133] 40. Leaking steam pipeline

[0134] 41 Guide sleeve

[0135] 42 pin connection

[0136] 43 Sealing ring

[0137] 44 Steam Filter

[0138] 45 Steam deflection device

[0139] 46 pin connections

[0140] 47 Groove

[0141] 48 Steam vent

[0142] 49 Diffuser

[0143] 50 Keep pin

[0144] 51 First Sealing Area

[0145] 52 Second sealing area

[0146] 53. Eddy Current Damaging Device

[0147] 54 Eddy Current Damage Teeth

[0148] 55 Steam Inlet

[0149] 56 Control Edge

[0150] 57 First end position

[0151] 58 Second paragraph position

[0152] 59 Interior Space

[0153] 60 sleeve

[0154] 60a radial hole

[0155] PT61 Pressure Measurement Device

[0156] PT62 Pressure Measurement Device

[0157] 63 Axial groove

[0158] 64. Tubular valve body

[0159] 65 steps

[0160] 66 Propelling Body

[0161] 67 Pulling body

[0162] 68 tensioners

[0163] 69 holes

[0164] 70 Pressure relief hole

[0165] 71 holes

[0166] 72-level main body

[0167] D k Contact diameter

Claims

1. A combination valve (1) for a steam circuit, comprising a quick-closing valve (2) and a regulating valve (3), wherein, The quick-closing valve (2) and the regulating valve (3) are housed in a common housing (4, 5). The regulating valve (3) can be moved by an active actuator, and the quick-closing valve (2) can be moved passively by steam in the steam circuit over the full stroke between the open and closed positions. During continuous operation of the steam circuit, when the regulating valve (3) is in the open position, a partial stroke test can be performed on the quick-closing valve (2), wherein the partial stroke test is characterized in that the quick-closing valve (2) moves only a portion of its full stroke. The quick-closing valve (2) is exposed to steam, thereby moving it in the closing direction. The combined valve is adapted such that, due to the movement of the quick-closing valve (2) in the closing direction, the throttling point opens, and steam can escape through the throttling point, thereby preventing the quick-closing valve (2) from moving further in the closing direction and stopping at a partial stroke position.

2. The combined valve (1) according to claim 1, wherein, Each of the pressure sensors (PT61, PT62) is located upstream and downstream of the throttling point, respectively.

3. The combination valve (1) according to any one of claims 1 to 2, wherein, The regulating valve (3) is implemented as a pressure-relieving tubular regulating valve.

4. The combined valve (1) according to any one of claims 1 to 2, wherein, The regulating valve (3) is implemented as a pre-stroke regulating valve.

5. The combination valve (1) according to any one of claims 1 to 2, wherein, The quick-closing valve (2) is configured to have a sleeve-shaped quick-closing valve body (19), and the regulating valve (3) is configured to have a tubular valve body (64), wherein the tubular valve body (64) of the regulating valve (3) is guided inside the sleeve-shaped quick-closing valve body (19).

6. The combination valve (1) according to any one of claims 1 to 2, wherein, The quick-closing valve (2) and the regulating valve (3) can move independently of each other, and the regulating valve (3) in the closed state stops the flow of steam through the combined valve.

7. The combination valve (1) according to any one of claims 1 to 2, comprising a switchable control valve (26) for switching the quick-closing valve (2).

8. The combined valve (1) according to claim 7, wherein, The control valve (26) is a 3 / 2-way valve.

9. The combined valve (1) according to claim 7, wherein, The control valve (26) has a hydraulically or pneumatically operated control actuator.

10. The combination valve (1) according to any one of claims 1 to 2, wherein, The regulating valve (3) has a regulating valve actuator (8) as an active actuator, which is implemented as a low-pressure hydraulic actuator or an electric actuator.

11. The combination valve (1) according to any one of claims 1 to 2, wherein, The shell (4, 5) is composed of a shell base (4) and a shell cover (5), wherein the shell base (4) is connected to the shell cover (5) by means of force fit and / or shape fit.

12. The combination valve (1) according to any one of claims 1 to 2, wherein, The housing (4, 5) has a steam filter (44) at the steam inlet (55), the steam filter (44) including a steam deflection device (45) that allows the steam to be deflected by an angle of 10° to 80°.

13. The combined valve (1) according to claim 12, wherein, The steam deflection device (45) enables the steam to be deflected by an angle of 25° to 65°.

14. The combined valve (1) according to claim 12, wherein, The steam deflection device (45) enables the steam to be deflected at an angle of 30° to 55°.

15. The combined valve (1) according to claim 12, wherein, The steam deflection device (45) enables the steam to be deflected at an angle of 40° to 50°.

16. The combined valve (1) according to claim 12, wherein, The steam deflection device (45) enables the steam to be deflected at an angle of 45°.

17. The combined valve (1) according to claim 12, wherein, The steam filter (44) is detachably connected to the housing cover (5) of the housing (4, 5).

18. The combination valve (1) according to any one of claims 1 to 2, wherein, The housing (4, 5) has a diffuser (49) at the steam outlet (48).

19. The combined valve (1) according to claim 18, wherein, The diffuser (49) is detachably disposed in the housing base (4) of the housing (4, 5).

20. The combined valve (1) according to claim 18, wherein, The diffuser (49) includes a vortex-breaking device (53).

21. The combined valve (1) according to claim 20, wherein, The eddy current breaking device (53) is configured as a guide for the regulating valve (3).

22. The combination valve (1) according to any one of claims 1 to 2, wherein, During operation of the combined valve, the rear side of the quick-closing valve body (19) of the quick-closing valve (2) is under no pressure when the quick-closing valve (2) is in the open position.

23. The combination valve (1) according to any one of claims 1 to 2, wherein, The regulating valve (3) has a valve stem shaft (10) with a valve stem seal (17), wherein during operation of the combined valve, one side of the valve stem seal (17) is exposed to ambient pressure and the opposite side is pressureless.

24. A SIL 3 certified safety circuit comprising the combination valve (1) according to any one of claims 1 to 23.

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