CONTROL VALVE

Description

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

[0002] Control valves are well known in the art and typically comprise a valve housing with a valve inlet and outlet, as well as a valve cover sealingly closing the valve housing. To control / regulate the flow of a process medium flowing through the control valve, a valve seat fixed to the housing is arranged or formed in the flow channel of the valve housing, i.e., between the valve inlet and outlet. This valve seat interacts with a valve element that is movable relative to the valve seat and designed to complement the valve seat. The valve seat is driven by an actuator rod connected to the valve element, which is passed sealingly through the housing cover and is operatively connected to a drive, in particular a pneumatic drive, provided on the outside of the housing.

[0003] It is also well known that when used under extreme conditions, such as process media with extremely high or extremely cold temperatures, thermal expansion, particularly of the valve seat and valve element components, can lead to altered gap geometries that negatively impact internal tightness and the rangeability. This is due to the fact that - since the spatial expansion of the valve element is small compared to the valve seat and valve body components due to its design - when heat is introduced or dissipated, the valve element, valve seat, and valve body components experience different thermally induced length changes, which undesirably impact the internal tightness and the rangeability. The same applies if different materials are used for the valve element, valve seat, and valve body components.Since different materials usually have different thermal expansion behavior, the negative influences must be observed accordingly.

[0004] Another well-known problem when using control valves under extreme process medium temperatures is that the extreme temperatures of the process medium also negatively affect the tightness and control behavior of the sealing arrangement installed in the housing cover, which seals the actuator stem to the outside of the actuator. Particular attention must be paid to a temperature-related increase in friction between the actuator stem and the sealing arrangement, which can potentially lead to jamming of the actuator stem, severely impairing or even completely preventing control of the control valve.

[0005] To protect the sealing arrangement from extreme process media temperatures, it is known to provide the valve housing, i.e., the valve body containing the valve inlet and outlet, with an extension body that extends the valve housing in the axial direction a toward the valve cover and acts as an insulating part (see DE 10 2019 104 589 A1). A disadvantage of this approach is that the provision of the insulating part increases the height of the valve structure. Especially for low-temperature applications, operators of cold box systems are demanding increasingly smaller valve installation angles in order to be able to install as many control valves as possible in a cold box, so that the prior art solution is no longer practical.

[0006] In order to reduce thermal damage and / or adverse thermal influences on components subject to high thermal stress, it is known to use materials with low thermal conductivity. This includes, for example, aerogels. Aerogels are highly porous solids whose volume consists largely of pores. An aerogel can be made from silicate or carbon, for example. Aerogels are usually designed in the form of a strongly dendritic structure, in which there is a branching of particle chains with a large number of spaces in the form of open pores. The particle chains have contact points, resulting in a structure in the form of a stable, sponge-like network. The pore size of the open pores can be in the nanometer range. Aerogels can be used to coat components or even to produce entire components.

[0007] The use of aerogels in sensitive areas of valves to protect them from harmful thermal influences is known from the prior art: US 2,464,242 A discloses a control valve whose valve body is extended by an insulating part. To reduce heat transfer via the actuator stem, US 2,464,242 A proposes making the actuator stem hollow and filling it with an aerogel-based material.

[0008] US 2015 / 03083031 A1 discloses an injection valve for an internal combustion engine. To protect the valve member, which is exposed to high thermal loads, US 2015 / 0308303 A1 proposes partially providing the valve member with an aerogel surface coating.

[0009] WO 2016 / 049252 A1 discloses a control valve subject to high thermal stress and a positioner flanged to the control valve. To protect the positioner flanged to the control valve, WO 2016 / 049252 A1 proposes a multi-layered housing wall of the positioner adjacent to the control valve subject to high thermal stress, in particular by sandwiching an aerogel-based insulation layer between two other material layers.

[0010] DE10 2018 214650 A1 discloses a control valve according to the preamble of claims 1 and 3.

[0011] The invention is based on the object of developing a control valve according to the type specified in the preamble of claim 1 in such a way that flawless operation of the control valve is possible even when used under extreme boundary conditions, namely process media with extremely high or extremely cold temperatures. In particular, flawless operation of the control valve with regard to internal tightness and rangeability, as well as flawless operation with regard to smooth actuation of the actuator stem, should be ensured.

[0012] The object according to the first aspect, namely to enable a perfect operation of the control valve with regard to the internal tightness and the control ratio, is achieved by the characterizing features of claim 1 in conjunction with its preamble features.

[0013] Subclaim 2 represents an advantageous development of the control valve according to the invention according to claim 1.

[0014] In a known manner, the control valve comprises a valve housing with a valve inlet and valve outlet, as well as a valve cover sealingly closing the valve housing. To control / regulate the flow of a process medium flowing through the control valve, the control valve further comprises, in a known manner, a valve seat fixed to the housing arranged in the flow channel between the valve inlet and valve outlet, a valve member designed complementarily to the valve seat and movable relative to the valve seat, and an actuator stem sealingly guided through the housing cover, via which the valve member can be connected to a drive on the outside of the housing. The valve cover comprises a sealing arrangement by means of which the actuator stem is sealed against the valve cover.

[0015] According to the invention, it is now provided that the valve seat is formed from an aerogel material or coated with an aerogel coating and / or that the valve member is formed from an aerogel material or coated with an aerogel coating. In particular, the valve seat and / or the valve member (each) is / are formed at least partially or at least substantially entirely from the aerogel material.

[0016] The inventive design has the effect that – since the thermal conductivity of the valve seat and valve member components is now greatly reduced – the heat input and output to and from the components is greatly reduced, with the consequence that thermally induced changes in length of the valve seat and valve member components are also greatly reduced. This advantageously ensures that no or almost no changes in length of the valve seat and valve member components occur, so that the designed geometric relationships between the valve seat and valve member are maintained over a larger thermal application range. This means that the desired function or its characteristics are maintained, e.g., the designed leakage class according to IEC 60534-4 or the specified rangeability.

[0017] If the control valve is designed as a cage valve, i.e. the control valve further comprises a valve cage fixed to the housing and arranged in the flow channel between the valve inlet and valve outlet, an advantageous further development provides that the valve cage is also made of an aerogel material or is coated with an aerogel coating. This advantageously ensures that even when the control valve is designed as a cage valve, the designed geometric relationships are maintained over a larger thermal application range. In particular, the valve cage is formed at least partially or at least substantially completely from the aerogel material. Preferably, the valve cage is at least substantially completely coated with the aerogel coating.Alternatively, it is conceivable that the valve cage is coated with the aerogel coating, in particular only in a contact area with the valve seat and / or the valve housing, in particular in order to reduce heat transfer from the valve seat to the valve cage or the valve housing.

[0018] The object according to the second aspect, namely to enable a perfect operation of the control valve with regard to a smooth actuation of the actuator stem, is achieved by the characterizing features of claim 3 in conjunction with the preamble features of claim 1.

[0019] Subclaims 4 to 9 represent advantageous developments of the control valve according to the invention according to claim 3.

[0020] According to the invention, the sealing arrangement arranged in the valve cover of the valve housing and sealing the actuator rod relative to the valve cover is assigned an insulating body made of an aerogel material or coated with an aerogel coating. Preferably, the insulating body is substantially completely coated with the aerogel coating. Alternatively, it is conceivable that the insulating body is coated with the aerogel coating only in the areas facing the actuator rod and / or the valve cover, in particular in the areas adjacent thereto.

[0021] The term "an insulating body arranged inside the valve housing and associated with the sealing arrangement" is generally understood to mean a component arranged inside the valve housing that is in direct or indirect contact with the sealing arrangement and is suitable for reducing heat input into the sealing arrangement or heat transport out of the sealing arrangement.

[0022] The design according to the invention proves to be particularly advantageous since, due to the provided insulating body made of an aerogel material or coated with an aerogel coating, the heat input or output into or from the sealing arrangement is greatly reduced, with the result that even critical temperatures of the sealing arrangement, which can lead to an increase in friction between the drive rod and the sealing arrangement or, under certain circumstances, to jamming of the drive rod in the sealing arrangement, are avoided.

[0023] This design proves particularly advantageous, particularly when using cryogenic media as process media, i.e., in low-temperature applications, since the insulating body arranged according to the invention inside the valve housing, made of an aerogel material or provided with an aerogel coating, eliminates the need for the previously conventional valve housing design according to the prior art (cf. DE 10 2019 104 589 A1), namely the axial extension of the valve housing by means of an extension body acting as an insulating part. This means that, due to the now smaller valve installation angles—as required by operators of coldbox systems—more valves can be installed in a coldbox.

[0024] According to one embodiment, the insulating body is designed as a disc located in the valve cover, positioned below the sealing arrangement as viewed in the axial direction a. This advantageously enables particularly compact insulation of the sealing arrangement.

[0025] According to a further, particularly preferred embodiment, the insulating body is designed as a displacement body that is axially clamped, viewed in the axial direction a, between the housing cover and another valve component permanently installed in the valve housing, and that concentrically surrounds the actuator stem. Due to the axial clamping between the valve cover and the other valve component, such as a circulation barrier or a valve cage, a secure fit of the insulating body is ensured in a simple manner.

[0026] Preferably, the displacement body is essentially sleeve-shaped, completely filling the housing interior, viewed in the radial direction r, between the actuator stem and the adjacent inner wall of the valve housing. Since the entire housing interior is now filled by the sleeve-shaped displacement body, particularly effective insulation of the sealing arrangement is ensured.

[0027] A further preferred embodiment provides that the drive rod passing through the sealing arrangement is made of an aerogel material or coated with an aerogel coating, so that the drive rod itself forms the insulating body associated with the sealing arrangement. The advantage of this embodiment is that no additional components are required for the intended insulation of the sealing arrangement.

[0028] In order to reduce heat input or output into the sealing arrangement via the valve cover, the valve cover is preferably also made of an aerogel material or coated with an aerogel coating.

[0029] Preferably, the valve member is also made of an aerogel material or coated with an aerogel coating. This ensures that heat transfer from the valve member via the valve stem to the sealing arrangement is prevented.

[0030] The subject matter of sub-claims 10 to 15, which are further assessed below, represent advantageous developments of the control valve according to claims 1 and 3: In order to ensure good sealing properties with minimal installation space, the sealing arrangement provided in the valve cover is preferably designed as a stuffing box packing. The actuator rod is preferably designed in two parts and comprises a valve member rod connected to the valve member and an actuator rod which is firmly connected to the valve member rod, is passed through the housing cover in a sealing manner and can be brought into operative connection with a drive. However, a one-piece design of the actuator rod is also conceivable, i.e. the actuator rod has an actuator rod section inside the housing that is connected to the valve member and an actuator rod section outside the housing, i.e. passes out of the valve housing in a sealing manner and can be connected to a drive.

[0031] The aerogel material is preferably a semi-metal or metal oxide, such as silicon dioxide, titanium oxide, or aluminum oxide, but carbon-based substances are also conceivable. As initial tests have shown, these materials, due to their thermal conductivity, are particularly advantageous for the present application in a control valve.

[0032] The aerogel coating is preferably a composite of the previous materials with synthetic resins or polyamides or even pure material.

[0033] It is also proposed that the valve seat be coated with the aerogel coating, in particular only in a contact area where the valve seat is connected to the valve housing. Temperature-induced deformation of the valve seat and / or other temperature-induced effects on the valve seat in the contact area can advantageously be prevented. This advantageously ensures unhindered installation and removal of the valve seat. Advantageously high modularity and advantageously simple maintenance of the control valve can be enabled, in particular when used in an environment and / or with media with relatively high or low temperatures. Preferably, the valve seat is formed separately from the valve housing. Preferably, the valve seat is formed so as to be removable or replaceable. In particular, in an assembled state, the valve seat is connected to the valve housing in a force-fitting and / or form-fitting manner.It is conceivable that the valve seat is screwed, clamped, or tensioned to the valve housing in the assembled state. The valve seat preferably rests at least partially against the valve housing, in particular an inner wall of the valve housing, via the contact region. In particular, the contact region of the valve seat extends over an outer surface of the valve seat, which comprises at least one bearing surface of the valve seat on the valve housing. It is conceivable that the contact region or the outer surface of the valve seat extends beyond the bearing surface, preferably in order to prevent or reduce temperature-related effects on the valve seat due to its proximity to an inner surface of the valve housing. Alternatively, it is conceivable that the valve seat and / or the valve member is / are coated with the aerogel coating, in particular only in a region of a throttle point of the control valve.In particular, the region of the throttle point of the control valve comprises a sealing edge of the valve seat and / or the valve member, which is preferably intended to interact with the valve member or the valve seat when the control valve is closed.

[0034] It is further proposed that the valve seat and / or the valve member be / is at least substantially completely coated with the aerogel coating. This can advantageously enable complete protection of the valve seat and / or the valve member against unwanted temperature-related effects, such as thermal deformation, particularly when using media with high temperatures. This advantageously allows a high level of reliability and service life of the control valve to be achieved under these conditions. The aerogel coating preferably extends over an outer surface of the valve seat and / or the valve member.The fact that a body, in particular the valve seat and / or the valve member, is substantially completely coated should be understood in particular to mean that a coating, in particular the aerogel coating, extends over or covers at least 95%, preferably at least 98%, and particularly preferably at least 99%, of the entire surface of the body. For example, it is conceivable for the valve member to be designed without a coating in a region facing the drive, in particular to enable a connection to another component of the control valve.

[0035] Further advantages and possible applications of the present invention will become apparent from the following description in conjunction with the embodiments shown in the drawings.

[0036] In the description, claims, and drawings, the terms and associated reference symbols used in the list of reference symbols below are used. In the drawings, the following definitions apply: Fig. 1 shows a sectional view of a control valve according to the invention; Fig. 2 shows a further embodiment of a control valve according to the invention in a sectional view; and Fig. 3 shows an enlarged section of a control valve according to the invention according to a further embodiment.

[0037] In the following description and in the figures, to avoid repetition, identical parts and components are marked with the same reference symbols unless further differentiation is necessary or useful.

[0038] Fig. 1shows a control valve, designated overall by reference numeral 10. The control valve 10 comprises, in a known manner, a valve housing 12 with a valve inlet 12-1 and a valve outlet 12-2. The valve cover, which seals the valve housing 12 against the environment, is designated by reference numeral 14.

[0039] To adjust the flow cross-section, the control valve 10 has, in a known manner, a valve seat 16 arranged in the flow channel of the valve housing 12, i.e. between the valve inlet 12-1 and the valve outlet 12-2, as well as a valve member 18 designed complementarily to the valve seat 16 and movable relative to the valve seat 16. As can be seen from Fig. 1 As can be seen, in the present case the valve seat 16 is designed as a separate component from the valve housing 12, which is detachably connected to the valve housing 12.

[0040] For valve actuation, the valve member 18 is operatively connected via an actuator rod 20 to a drive 22 arranged above the valve cover 14, as viewed in axial direction a. Fig. 1 As further shown, a sealing arrangement 24 is arranged in the valve cover 14, by means of which the actuator stem 20 is sealed against the valve cover 14. In the present case, the sealing arrangement 24 is designed as a stuffing box packing.

[0041] The Fig. 1 The control valve 10 shown is characterized in that the valve seat 16 and the valve member 18 are coated with an aerogel coating. Fig. 1The coating is symbolized by the thickened lines of the valve seat 16 and valve member 18 components. The aerogel coating has a strong insulating effect, with the result that even at extremely high or cold process medium temperatures, there is almost no heat input or heat dissipation from the process medium to the valve seat 16 and valve member 18 components. This advantageously ensures that no changes in the length of the valve seat 16 and valve member 18 components occur, so that the designed geometric relationships between the valve seat 16 and valve member 18 are maintained. The valve seat 16 is formed separately from the valve housing 12. The valve seat 16 is connected to the valve housing 12 and is designed to be removable or replaceable. The valve member 18 and the valve seat 16 are each essentially completely coated with the aerogel coating.Alternatively, it is conceivable that the valve member 18 and / or the valve seat 16 are coated individually or only partially, for example for the valve seat 16 only in a contact area 30 for a connection to the valve housing 12.

[0042] The Fig. 2 The control valve shown has an essentially identical design. As can be seen from Fig. 2As can be seen, the control valve 10 is designed as a so-called cage valve and, in a known manner, has a valve cage 26 fixed to the housing, arranged in the flow channel between the valve inlet 12-1 and the valve outlet 12-2. It is conceivable that the valve cage 26 is partially or substantially completely coated with an aerogel coating. For example, it is conceivable that the valve cage 26 is coated with the aerogel coating only in a contact area 32 with the valve seat 16 and / or the valve housing 12, in particular in order to reduce heat transfer from the valve seat 16 to the valve cage 26.

[0043] The Fig. 2 The control valve 10 shown is characterized in that the sealing arrangement 24 is assigned an insulating body made of an aerogel, designated overall by the reference number 28.

[0044] According to the Fig. 2In the embodiment shown, the insulating body 28 is sleeve-shaped and completely fills the housing interior, viewed in the radial direction r, between the actuator rod 20 and the inner wall of the valve housing 12 and is held clamped between the housing cover 14 and the valve cage 26, viewed in the axial direction a.

[0045] Also the Fig. 3 The embodiment shown in detail is characterized in that the sealing arrangement 24 is assigned an insulating body 28 made of an aerogel. As Fig. 3 As can be seen, the insulating body 28 is designed as a disc positioned in the housing cover 14 below the sealing arrangement 24 as viewed in the axial direction a

[0046] The provision of the insulating body 28 according to the invention proves to be particularly advantageous because, due to the insulating effect of the insulating body 28, harmful heat input into or heat dissipation from the sealing arrangement 24 is prevented, thus avoiding critical temperatures in the region of the sealing arrangement 24 that could trigger an increase in friction between the drive rod 20 and the sealing arrangement 24. Alternatively, it is conceivable that the insulating body 28 is partially or substantially completely coated with an aerogel coating. For example, it is conceivable that the insulating body 28 is coated with the aerogel coating only in the areas facing the drive rod 20 and / or the valve cover 14, in particular in areas adjacent thereto. List of reference symbols

[0047] 10Control valve 12Valve body 12-1Valve inlet 12-2Valve outlet 14Valve cover 16Valve seat 18Valve element 20Actuator stem 22Actuator 24Seal assembly 26Valve cage 28Insulating body 30Contact area 32Contact area aaxial direction rradial direction

Claims

1. Control valve (10), comprising a valve housing (12) with a valve inlet and valve outlet (12-1, 12-2) and a valve cover (14), a valve seat (16) that is fixed to the housing and arranged in the flow channel between the valve inlet and valve outlet (12-1, 12-2), a valve member (18) that is designed to complement the valve seat (16), and a drive rod (20) which passes through the housing cover (14) in a sealing manner and which is used to connect the valve member (18) to a drive (22) located on the outside of the housing, which valve cover (14) comprises a sealing arrangement (24) which is used to seal the drive rod (20) with respect to the valve cover (14), characterized in that the valve seat (16) and / or the valve member (18) are / is made of an aerogel material or are / is coated with an aerogel coating.

2. Control valve (10) according to claim 1, characterized in that, furthermore, a valve cage (26) that is fixed to the housing is arranged in the flow channel between the valve inlet and the valve outlet (12-1, 12-2), which cage is made of an aerogel material or is coated with an aerogel coating.

3. Control valve (10) according to the preamble of claim 1, characterized by an insulating body (28) arranged in the interior of the valve housing (12) and associated with the sealing arrangement (24), which insulating body (26) is formed from an aerogel material or is coated with an aerogel coating.

4. Control valve (10) according to claim 3, characterized in that the insulating body (28) is designed as a disk which is positioned underneath the sealing arrangement (24), as viewed in the axial direction (a), and arranged in the valve cover (14).

5. Control valve (10) according to claim 3, characterized in that the insulating body (26) is designed as a displacement body which concentrically encloses the drive rod (20) and which, as viewed in the axial direction (a), is held axially clamped between the valve cover (14) and another valve component (26) permanently installed in the valve housing (12).

6. Control valve (10) according to claim 5, characterized in that the displacement body is shaped like a sleeve and designed to completely fill the interior of the housing, as viewed in the radial direction (r), between the drive rod (20) and the inner wall of the valve housing (12).

7. Control valve (10) according to claim 3, characterized in that the drive rod (20) passing through the sealing arrangement (24) is made of an aerogel material or is coated with an aerogel coating, so that the drive rod (20) itself forms the insulating body associated with the sealing arrangement (24).

8. Control valve (10) according to claim 7, characterized in that, furthermore, the housing cover (14) is made of an aerogel material or is coated with an aerogel coating.

9. Control valve ( / 10) according to any one of claims 7 or 8 above, characterized in that, furthermore, the valve member (18) is made of an aerogel material or is coated with an aerogel coating.

10. Control valve (10) according to any one of the preceding claims, characterized in that the sealing arrangement (24) is designed as stuffing box packing.

11. Control valve (10) according to any one of claims 1 to 10 above, characterized in that the drive rod (20) is formed in two parts and comprises a valve member rod connected to the valve member (18) and an actuator rod connected thereto, which latter passes through the valve cover (14) in a sealing manner and is adapted to be connected to a drive (22).

12. Control vale (10) according to any one of the preceding claims, characterized in that the aerogel material is a metalloid oxide, or a metal oxide, or a carbon-based substance.

13. Control valve (10) according to any one of the preceding claims, characterized in that the aerogel coating is made of metalloid oxides, of metal oxides, or of carbon-based substances, in combination with synthetic resins or polyamides.

14. Control valve according to any one of the preceding claims, characterized in that the valve seat (16) is coated with the aerogel coating, in particular only, in a contact area (30) for a connection of the valve seat (16) to the valve housing (12).

15. Control valve according to any one of the preceding claims, characterized in that the valve seat (16) and / or the valve member (18) are / is at least substantially completely coated with the aerogel coating.