Device for controlling the passage of a fluid

Abstract

1. A valve (1) for regulating a flow of a fluid, the valve (1) comprising: a valve body (2), an inlet for the fluid, an outlet for the fluid, a flow regulating member (8), a chamber (7) for receiving the fluid within the valve body, and a valve seat (21), the valve body comprising an outer body portion (4) and an inner body portion (3) which mate with each other and / or are mechanically joined to each other, the outer body portion made of a first material and the inner body portion made of a second material, the first and second materials being different from each other, the inner body portion including a surface exposed to the chamber, the surface being in direct contact with the fluid within the chamber during operation.

Description

[Technical field]

[0001] The present invention relates to a device for controlling the passage of a fluid, different parts of which are made of different materials, and to its use. The device is, for example, a valve. [Background technology]

[0002] A valve is a device that regulates, directs, or controls the flow of a fluid (gas, liquid, fluid solid, or slurry) by opening, closing, or partially obstructing various flow paths. When a valve is open, fluid flows in a direction from higher pressure to lower pressure.

[0003] Highly corrosion resistant valves are desired, for example for use in chemical plants, which come into contact with highly corrosive process fluids during operation. In particular, valves capable of regulating highly corrosive fluids (especially liquids) at high pressures (e.g., above 100 bar), high temperatures (e.g., above 100° C.), which valves have a long life, low maintenance costs, and low capital costs. It is an object of the present disclosure to provide a valve that addresses one or more of these needs.

[0004] No. 3,913,610 describes a butterfly valve which includes a tubular sleeve member formed from a relatively high strength metal, the sleeve member also having an internal resilient lining.

[0005] US 4,161,187 describes a control valve for regulating the flow of aggressive fluids. The valve has an outer body made of stainless steel and an inner body consisting of three sleeves made of chromium carbide or tungsten carbide. The valve plug and seats are also made of such carbides.

[0006] No. 4,356,612 describes an improved forged steel structure (eg a valve) which is lined with a corrosion resistant metal and the lining and body are forged together. Valve improvements are still desired. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] U.S. Pat. No. 3,913,610 [Patent Document 1] U.S. Pat. No. 4,161,187 [Patent Document 1] U.S. Pat. No. 4,356,612 Summary of the Invention [Means for solving the problem]

[0008] The present invention provides in a first aspect a valve for regulating a flow of a fluid, comprising a valve body, an inlet for the fluid, an outlet for the fluid, a flow regulating member, a chamber for receiving the fluid disposed within the valve body, and a valve seat, the valve body comprising an outer body portion and an inner body portion which mate with and / or are mechanically joined to one another; The valve thereby preferably has an outer body portion made from a first material and whereby the inner body portion is made from a second material, the first and second materials preferably being different from each other, and the inner body portion preferably including a surface exposed to said chamber and which during operation is in direct contact with said fluid in the chamber.

[0009] The invention also provides the use of such a valve for regulating fluid flow.The invention also provides a method of regulating fluid flow comprising passing a fluid through such a valve. [Brief description of the drawings]

[0010] [Figure 1] 1 illustrates a schematic representation of an example valve according to the present invention; [Diagram 2] 1 shows different views of an example valve according to the invention; [Diagram 3] 1 shows different views of an example valve according to the invention; [Figure 4] 1 shows different views of an example valve according to the invention; [Diagram 5] 1 shows different views of an example valve according to the invention; [Figure 6] 1 shows different views of an example valve according to the invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] All the illustrated embodiments are merely examples and are not intended to be limiting of the present invention.

[0012] Advantageously, in the valve of the present invention, the outer body portion does not need to be made of a corrosion resistant material, even if the fluid in the chamber is corrosive, since it does not come into direct contact with the fluid in the chamber, thereby allowing cheaper materials to be used for the outer body portion.

[0013] The valve is useful for regulating the flow of particularly highly aggressive fluids (e.g. liquids and / or gases), in particular in chemical plants. Furthermore, the valve is very suitable for regulating the flow of fluids with high pressure (e.g. more than 50 bar, more than 100 bar or even more than 150 bar). The valve is configured for example to regulate the flow of fluids with pressures of more than 50 bar, more than 100 bar or even more than 150 bar (absolute). The valve is also very suitable for regulating the flow of fluids with temperatures of more than 100° C. or more than 150° C., the fluids being for example in said high pressure range and / or being highly corrosive. In the uses and methods of the invention, for example such fluids are used.

[0014] Advantageously, due to the relatively small size of the inner body portion as compared to a comparable valve body made as a single piece, the inner body portion can be made from duplex stainless steel, which has good corrosion resistance and mechanical properties.

[0015] The use of inner and outer body parts that are fitted together and / or mechanically joined (e.g. connected) to one another has the advantage that relatively complex shapes can be realised for the chamber that receives the fluid during operation. This is an advantage over linings for example. Preferably, the inner body part is releasably or removably held within the outer body part by the inner and outer body parts being fitted together and / or mechanically joined to one another. Preferably, when the inner and outer body parts are mechanically joined to one another, releasable connection means are used to connect the inner and outer body parts.

[0016] The lining process involves applying a thin layer of a suitable material (e.g. PTFE, usually a polymeric material) to the internal equipment surfaces in contact with the medium (surfaces that should be protected against corrosion). The lining process in general is not applicable for valves due to several limitations. For example, the maximum permissible temperature is too close to the operating temperatures in chemical plants, such as the HP section of a urea plant. The lining material is a soft thermoplastic material, which cannot guarantee an adequate lifetime against erosion, corrosion and / or cavitation. The lining material is a soft thermoplastic material, which cannot guarantee an adequate lifetime for the high pressures involved (e.g. at least 100 bar). Cladding with duplex stainless steel by welding is in general not an attractive option for valve bodies, due to the complex internal geometry of the valve body. Furthermore, the unavoidable microporosity may compromise the function of the valve.

[0017] The inner body portion may be made from a highly corrosion resistant steel, such as, for example, duplex stainless steel.

[0018] The present invention relates to a device for controlling the passage of a fluid, whereby different parts of the device are preferably made of different materials. The device is, for example, a valve.

[0019] The invention also relates to the use of the device for controlling the passage of a fluid, in particular the use of a device (e.g. a valve) for regulating the flow of a fluid which is highly corrosive and / or has a pressure of more than 50 bar, more than 100 bar or even more than 150 bar and / or a temperature of more than 100°C or more than 150°C.

[0020] Valves generally can be used to stop and start a fluid flow, or to vary the amount of a fluid flow, or to control the direction of a fluid flow, for example, or to relieve overpressure, for example. A valve can also be referred to as a device for controlling the passage of a fluid, or a device for regulating the flow of a fluid.

[0021] The valve body (or valve shell) is the primary pressure boundary of the valve. It holds the valve components together. During operation, the valve body withstands the fluid pressure loads from the connecting pipes. The valve body receives the inlet and outlet piping through joints. The valve body typically contains openings for assembly of the valve, particularly for assembly of the flow-regulating internal components into the valve body.

[0022] The valve includes a first opening and a second opening in the valve body for allowing fluid to enter and exit the valve body. The openings are specifically configured to allow fluid to enter and exit a chamber for holding the fluid, the chamber being provided in the valve body. Thus, the valve includes an inlet and an outlet. The valve may include more than one inlet and may include more than one outlet.

[0023] The valve also includes a flow control member, i.e., an internal flow control element (e.g., a control stem or disk). The flow control member can be moved between at least two different positions within the chamber to regulate the flow of the fluid. The flow control member is disposed within the chamber. The valve typically includes a stem that connects the flow control member to a control device (e.g., an actuator or a handle). The flow control member can be, for example, a plug, e.g., a pressure retaining component. The flow control member is typically a movable obstruction within the valve body that adjustably restricts the flow of fluid through the valve. The flow control member can typically be moved to a position where a passage or port of the valve is blocked to regulate the flow of the fluid. The flow control member is also known as a disk, and the flow control member can have a variety of shapes.

[0024] The valve includes, for example, a valve seat that provides a seating surface for the flow regulation member. The seat can be a surface of the valve body, but is preferably a separate element of the valve from the valve body. Thus, the valve body (particularly the inner body) and the valve seat are preferably separate and distinct elements. The valve seat provides, for example, an inner surface of the valve body that contacts the flow regulation member to form a leak-tight seal at least at one location of the flow regulation member.

[0025] The flow control member is connected to a control device (e.g., an actuator) by, for example, a stem. The actuator is, for example, located outside the valve body. The stem transmits motion, for example, from a handle or actuator, to the flow control member. The actuator is, for example, a control device for the valve, and includes, for example, a motor.

[0026] The valve usually comprises a removable piece that allows assembly of the valve, in particular the assembly of the inner body part into the recess of the outer body part. In some embodiments, this piece is provided by a valve seat and a seat connection piece. The removable piece is connected to the valve body, for example by bolts. The removable piece may comprise openings for the flow of fluids and may be connected to a pipe.

[0027] The valve may, for example, have a valve body size of 4 inches (10.2 cm) or more, such as 8 inches (20.3 cm) or more. The valve may, for example, have a nominal inside diameter of 70 mm or more, such as 142 mm or more, and / or the valve may, for example, have a seat diameter of 10 mm or more, or 100 mm or more, such as 170 mm or more.

[0028] The valve body includes a chamber for receiving a fluid. In the valves of the present disclosure, the inner body portion provides the chamber. The walls of the chamber are provided by the inner body portion. In particular, the walls of the chamber are provided only by the inner body portion and not by the outer body portion. The chamber is contained within the inner body portion.

[0029] The valve may be, for example, without limitation, an angle globe valve, a straight globe valve, a butterfly valve, or a check valve. An angle globe valve may be, for example, a controlled valve or an on-off valve. A straight globe valve may be, for example, a controlled valve or an on-off valve. A butterfly valve may be, for example, a controlled valve or an on-off valve.

[0030] The valve may, for example, include a movable plug or disk element and a fixed valve seat. The plug is typically movable within a chamber configured to receive a fluid within the body.

[0031] The valve seat provides a stable, uniform and usually replaceable blocking surface. The valve seat may be, for example, a ring seat.

[0032] The valve may for example, without limitation, be designed to withstand at least 50 bar gauge, or at least 100 bar gauge pressure, or at least 240 bar gauge with high pressure fluid therein.

[0033] The valve body includes an inner body portion and an outer body portion that are mated and / or mechanically joined to one another such that the inner body portion and the outer body portion are separate components.

[0034] The inner body part is for example mechanically held in the outer body part, in particular in a recess in the outer body part. The inner body part is for example fitted in a recess in the outer body part. Thus, the inner and outer body parts can be fitted together, for example using an interference fit or a friction fit. The inner and outer body parts are for example mechanically attached to each other. The inner body part is usually mechanically held in a predetermined position in the outer body part, for example by a sheet connecting piece. Above are given exemplary examples where the inner and outer body parts are mechanically joined to each other. An interference fit and a friction fit are suitable to releasably hold the inner body part in a predetermined position in the recess in the outer body part. The inner and outer body parts are preferably each rigid, more preferably separate metal parts.

[0035] Typically, the inner body part is releasably held, e.g. removably held, in position in the outer body part. The outer body part typically includes a recess for receiving the inner body part, in particular for assembly of the valve, and preferably for disassembly of the valve. The valve body may include a gap between the inner body part and the outer body part, i.e. the inner body part and the outer body part are separate parts. The valve body may also include a sealing element for said gap. In embodiments where the inner body part can be released from the outer body part, advantageously the inner body part can be selectively replaced or exchanged for maintenance purposes and to mitigate even minor wear, corrosion or erosion caused by the process fluid in the chamber.

[0036] Thus, preferably, the outer body portion has a recess for receiving the inner body portion, more particularly for receiving and releasably holding the inner body portion, in such an embodiment the inner body portion is movable, e.g. slidable, from the outer body portion.

[0037] Preferably, the outer body portion is made from a first material and the inner body portion is made from a second material, the first and second materials being different from each other, which may advantageously allow for reduced manufacturing costs.

[0038] The inner body portion includes a surface exposed to said chamber, i.e. a surface that provides a boundary for said chamber and that is in direct contact with said fluid in the chamber during operation. Preferably, the inner body portion is partially exposed to said chamber and partially in direct contact with fluid during operation.

[0039] The outer body portion is made of, for example, without limitation, carbon steel, duplex stainless steel, or austenitic stainless steel. In an interesting embodiment, the outer body portion is made of carbon steel. Other materials are possible, for example duplex stainless steel. However, the outer body portion is made of a material other than duplex stainless steel in some embodiments. The use of a material other than duplex stainless steel may be advantageous, firstly, in view of the high content of expensive alloying elements in highly corrosion-resistant duplex stainless steels, and secondly, optionally, due to the need to control the microstructure of duplex stainless steels, which is difficult in large equipment parts.

[0040] The outer body portion is made of, for example, carbon steel, austenitic stainless steel, and / or stainless steel containing up to 27.0 wt.% Cr, such as 10.0-27.0 wt.% Cr, for example stainless steel containing 10.0-25.0 wt.% Cr, or for example 17.0-25.0 wt.% Cr.

[0041] The outer body portion may for example have a wall thickness of at least 10 mm, or at least 20 mm, or at least 100 mm, or at least 300 mm, whereby the outer body portion typically contributes to the mechanical strength of the valve.

[0042] The valve is configured to ensure that the outer body portion does not come into contact with corrosive process fluids during operation.

[0043] The outer body portion may be, for example, a single (integral) piece of metal, which is particularly advantageous for high pressure valves.

[0044] The outer body part comprises, for example, a recess for holding the inner body part and at least two openings providing a passage for the fluid. Typically, the valve comprises for each of said openings a hollow element extending through said opening, through which the fluid can flow between the chamber and the opening, in particular through said element, without direct contact with the outer body part. The element is, for example, tubular. At least one of said hollow elements may be provided by the inner body part.

[0045] Typically, the outer body portion also includes an opening through which the stem of the flow regulating member extends. For example, the outer body portion includes an opening through which a portion of the inner body portion extends, said portion of the inner body portion including the stem packing. Preferably, the valve body includes two separate passages or ports for fluid flow to and from the chamber, both of which extend through the inner and outer body portions.

[0046] The inner body portion is in direct contact with the process fluid during operation, the inner body portion includes a chamber and has a surface directly exposed to the chamber, the chamber receiving the process fluid during operation, the chamber having, for example, a concave, curved inner surface.

[0047] In some embodiments, the surface of the chamber is preferably curved and doubly concave, i.e. concave in two orthogonal directions over at least 50% of said surface, as shown in Figures 2 and 5. This may contribute to favorable fluid flow patterns within the chamber, e.g. reducing erosion, especially in the case of liquids at high pressure. For manufacturing inner body parts with chambers of such complex shapes, especially as one-piece, (duplex) stainless steels are advantageous.

[0048] Preferably, the parts of the inner body portion which provide the walls of the chamber fit completely within the recesses in the outer body portion in the assembled valve body.

[0049] The inner body portion is, for example, made of a corrosion resistant material, for example stainless steel (eg duplex stainless steel).

[0050] In embodiments where the inner body portion is made of duplex stainless steel, the outer body portion is preferably made of carbon steel. Advantageously, in such embodiments, the inner and outer body portions may have substantially the same coefficient of thermal expansion (e.g., less than 20% or less than 10% difference with respect to the coefficient of thermal expansion of the outer body portion). This embodiment is particularly advantageous for high temperature fluids (e.g., liquids) supplied to the valve (e.g., above 100° C. or above 150° C.).

[0051] The inner body part is for example a sleeve that mates with the outer body part, for example through an opening in the outer body part. The outer body part includes for example a recess for receiving the inner body part. This embodiment is particularly advantageous when a high pressure fluid (particularly a liquid) is supplied to the valve. Preferably, in this embodiment the inner body part is releasably held in place within the outer body part. The sleeve is for example a tubular sleeve provided as a single integral metal piece having an outer diameter smaller than the inner diameter of the (cylindrical) recess of the outer body part, said outer body part being a single integral metal piece.

[0052] The inner body portion is, for example, a sleeve provided in one part, two parts, or, for example, three or more parts, preferably provided in one or more parts. Optionally, the inner body portion is a single, integral part. Optionally, the inner body portion is a monolithic part.

[0053] By providing the inner body part as a single integral piece, more preferably made of duplex stainless steel, the risk of crevice corrosion is avoided compared to when the inner body part is made of two or more pieces. Furthermore, in this embodiment, the gap between the inner body part and the outer body part is less exposed to the process fluid compared to an embodiment in which the inner body part is provided as two or more pieces, because the gap between the inner body part can be completely shielded by the single integral inner body part compared to when the inner body part is provided as two or more pieces with gaps therebetween that would allow fluid in the chamber to access the outer body part. This is particularly advantageous when the outer body part is made of carbon steel, which is susceptible to corrosion by the fluid in the chamber.

[0054] The inner and outer body parts are preferably fitted together. The inner and outer body parts are connected to each other, for example, by mechanical connecting elements (for example pins or bolted components). The inner body part is held in a predetermined position within the outer body part. The inner and outer body parts can also be mechanically joined by an interference fit. For example, a sheet connecting piece may lock the inner body part in a predetermined position. It can be observed that the mentioned connecting means are suitable for releasably connecting the inner and outer body parts.

[0055] The inner body portion and the outer body portion together form a valve body. The inner body portion defines a chamber and includes at least two openings for fluids and typically also an opening for the stem.

[0056] The valve optionally includes an O-ring and / or a sealing element between the inner and outer body portions, for example to prevent external fluids from entering a gap between the inner and outer body portions.

[0057] The valve typically includes a sealing element, for example between the inner body part and the valve seat. A sealing element may also be simultaneously disposed between the protective element and the inner body part.

[0058] In embodiments where the inner body portion is made of two or more parts, the valve optionally includes, for example, O-rings and / or sealing elements between the parts of the inner body portion. The one or more sealing elements are, for example, sealing rings or metal-to-metal seals. The sealing elements are, for example, made of PTFE, PEEK, or are, for example, metallic seals. Other types of non-metallic seals are also possible.

[0059] The valve also includes, for example, a leak detection element, which is optional and is provided to detect even slight leakage of fluid, particularly process fluid, from the inner body portion to the outer body portion.

[0060] The valve seat is preferably releasably joined to the valve body. The valve seat can preferably be replaced for maintenance. The valve seat is preferably mechanically and releasably joined to the inner body part. In an example embodiment, the valve seat is supported by the inner body part. The valve seat is, for example, in direct contact with the inner body part. The valve seat and the inner body part are preferably separate pieces of equipment, in particular separate components. This has the advantage that the valve seat can be replaced independently.

[0061] The valve seat is made, for example, from duplex stainless steel, the same preferred alloy being used as for the inner body portion, and is typically configured to contact a flow control member (e.g., a plug) when the valve is in the closed position to seal the valve.

[0062] The valve seat optionally includes a notch extension, which advantageously contributes to a proper fit with the plug. The valve seat includes, for example, an extension having a mating surface for mating with the plug.

[0063] The valve comprises, for example, a seat connection piece. The seat connection piece is, for example, configured to hold the valve seat in place in the valve body. The seat connection piece is, for example, also configured to attach a tube or a pipe to the valve. The seat connection piece is, for example, attached or joined to the outer body part by means of a preferably releasable connection means, for example a stud bolt, for example a removable connection means. The inner body part is preferably in direct contact with the seat connection piece, for example a threaded flange. The seat connection piece can be removed from the valve body to allow replacement of the valve seat and / or the flow adjustment member (for example a stem with a plug). The seat connection piece is, for example, made of duplex stainless steel. The same material as for the inner body part is preferred. The seat connection piece is, for example, a tubular piece, one end of which is provided with a means for connection with a pipe (for example a flange) and the other end of which is fitted into an opening in the inner body part and is in direct contact with the valve seat. The seat connection piece is, for example, configured to hold the inner body part in place in a recess in the outer body part. The seat connection piece is typically configured to hold the valve seat in place within the valve body, for example the inner body part and the seat connection piece together provide a recess into which the valve seat fits and thereby holds the valve seat in place, whereby the seat connection piece is typically a pressure-bearing component.

[0064] In embodiments in which the inner body portion is releasably held within the outer body portion, the inner body portion may be removable from the outer body portion by removing the seat connection piece from the valve body, which may be used, for example, for replacement or inspection of the inner body portion.

[0065] In some embodiments, the valve includes a flow control member, a control stem and / or a stem and a plug. The control stem may include a stem and a plug. The plug can be moved in the chamber by the stem.

[0066] The valve includes, for example, an adjustable stem or stems and a plug arranged to move within the chamber between at least open and closed positions. The plug is in contact with a valve seat, for example, in the closed position. The stem extends at one end through an opening in the wall of the valve. The stem preferably comprises a plug at one end of the stem and at the other end the stem extends through an opening in the wall of the valve. For example, the stem and plug are an integral piece, or for example, the stem and plug are welded together. The stem and plug are preferably both made of duplex stainless steel or other corrosion resistant stainless steel.

[0067] Optionally, the stem extends through an opening only in the inner body portion, preferably with a stem packing in said opening. Optionally, the inner body portion includes a surface exposed to the exterior of the valve, the surface including the opening through which the stem extends. This embodiment provides an example of an embodiment in which some, but not all, of the exterior surface of the inner body portion is covered by the outer body portion.

[0068] The stem and plug contact the process fluid during operation and are preferably made from a highly corrosion resistant steel (eg, duplex stainless steel), with the same preferred materials being used as for the inner body portion.

[0069] In embodiments where the valve includes an opening for a stem, the valve typically includes stem packing to provide sealing, for example using self-pressurizing stem packing.

[0070] Examples of materials for the self-pressurizing stem packing include PTFE, PEEK, and a spring. The self-pressurizing stem packing includes, for example, a soft sealing ring, a support ring, and a spring. The spring is preferably made of stainless steel or other corrosion resistant material.

[0071] The stem packing includes, for example, a bushing and a seal.

[0072] Pressurization is beneficial for the sealing function. Compared to standard sealing used, pre-compression and regular checking of this pre-compression is not necessary with self-pressurizing stem packings. This means that self-pressurizing stem packings require little or no regular maintenance and minimize the risk of leakage during valve operation.

[0073] In a preferred embodiment, the valve includes a first opening in the inner body portion and a second opening in the outer body portion. The first opening and the second opening are aligned with one another such that fluid can flow between the second opening and the chamber. The opening in the inner body portion and the opening in the outer body portion collectively define an opening in the valve body.

[0074] Preferably, the valve includes a protective element arranged inside the second opening so as to prevent the outer body part from being exposed to the fluid in the second opening. The protective element can also be referred to as a pipe connection piece. The protective element is for example a tubular element, preferably having a radially extending end. The tubular element is inserted through an opening in the outer body part and also through an opening in the inner body part, preferably aligned with the opening in said outer body part. The preferred radially extending end of the tubular element can be used to releasably attach the tubular element to the outer body part. The preferred radially extending end is provided for example on the outside of the valve body. The end of the tubular element (for example the radially extending end) is arranged on the outside of the valve body, but may provide a flange for a pipe.

[0075] The protective element is preferably releasably (e.g. removably) attached or joined to the valve body (in particular to the outer body part). This may allow for easy replacement of the protective element. Removal of the protective element or the pipe connection piece may also allow the inner body part to be opened from the outer body part.

[0076] The protective element is made, for example, from duplex stainless steel, the same preferred alloy being used as for the inner body portion.

[0077] The valve comprises connection means (e.g. threads, etc.) for connecting a pipe to the valve. The protective element comprises an opening for the flow of fluid between the pipe and the valve chamber.

[0078] The valve may include a sealing system (e.g., a sealing ring) for sealing the protective element to the inner body portion. The sealing ring may, for example, be a soft sealing, e.g., a PTFE sealing ring, or a metal-to-metal sealing.

[0079] The protective element is, for example, screwed onto the outer body part. The valve, for example comprising a locking element that holds the protective element in place, is attached or joined to the outer body part, for example by means of a screw.

[0080] The inner body portion is made from bar stock, for example, without limitation, by hot working and / or cold working, and optional further heat treatment. Hot working is a process that plastically deforms steel above its recrystallization temperature, causing new, strain-free grains to form by the combined action of load and heat. Examples of hot working processes include forging, rolling, and extrusion. Cold working refers to plastically deforming steel below its recrystallization temperature. This creates permanent changes in the steel by introducing dislocations in its structure. The steel is then work-hardened. Some methods of cold working include cold rolling, cold pilgering, and cold drawing. Steels are typically heat treated to produce a wide variety of microstructures and properties. Annealing, normalizing, tempering, and quenching are different types of well-known heat treatments.

[0081] Heat treatment can be used to obtain the desired mechanical properties of the inner body part as well as the desired corrosion resistance properties. The relatively small size of the inner body part, especially the wall thickness (wall center distance), compared to a one-piece valve body (single valve body) for a comparable valve, contributes to achieving suitable mechanical and corrosion resistance properties by heat treatment. This is especially true in embodiments where the inner body part is made of duplex stainless steel. Heat treatment of the inner body part of duplex stainless steel can also be performed on bar stock elements with pre-drilled holes. Also, in the case of such a manufacturing method, the relatively small size of the inner body part (wall center distance) contributes to achieving suitable mechanical and corrosion resistance properties by heat treatment.

[0082] Aspects of the invention also relate to such methods of making an inner body part. For example, a method of making an inner body part (preferably made of duplex stainless steel) is provided that includes forming a steel body into a shaped body, heat treating, and optionally further shaping. The shaped body before heat treating includes, for example, drilled holes.

[0083] Suitable stainless steels for the inner body portion of the valve and all other components of the valve that come into contact with the fluid during operation (e.g., stem, plug, valve seat, protective elements) include, for example, duplex stainless steels. Thus, in some embodiments, all components of the valve that come into contact with the fluid are made of stainless steel (e.g., duplex stainless steel). For example, in this embodiment, the outer body portion is made of carbon steel.

[0084] The term "usually" as used herein denotes a characteristic that is frequently used, but not necessarily.

[0085] The term "duplex stainless steel" refers to austenitic-ferritic duplex stainless steels.

[0086] The term "fluid" is used to include gases and liquids, as well as two-phase fluid streams. A fluid stream may contain gases and / or liquids. A fluid stream may be, for example, a suspension.

[0087] FIG. 1 shows a schematic representation of an example valve (1) according to and / or for use in the present invention. The valve comprises a valve body (2) having an inner body portion (3) and an outer body portion (4) according to the present invention. The valve further comprises a first opening (5) and a second opening (6) for fluid to enter and leave the valve body, in particular for entering and leaving a chamber (7) for holding the fluid in the valve body. The valve also comprises a flow regulation member (8) (e.g. an adjustment stem or disk). The flow regulation member (8) can be moved between at least two different positions to regulate the flow of the fluid. The flow regulation member (8) is at least partially disposed within the chamber. The flow regulation member (8) may extend partially through the opening in the valve body.

[0088] An example valve (1) according to and / or for use in the present invention is shown in Figure 2. The valve includes a valve body (2) including an inner body portion (3) and an outer body portion (4). The inner body portion (3) is disposed within a recess (28) in the outer body portion (4). The illustrated inner body portion (3) and the outer body portion (4) are, for example, both a single integral piece, for example made of two different types of steel. The recess (28) and the outer surface of the inner body portion (3) have a mating shape with no gap between them, as shown.

[0089] The valve further includes a first opening (5) and a second opening (6) for fluid to enter and exit the valve body, particularly a chamber (7) for holding the fluid in the valve body. A flow control member (8) is provided as a plug (24) on the stem (25). A stem packing (9) is provided between the stem and the inner body portion. The stem extends through an opening (30) in the inner body portion. The stem is movable within the chamber to regulate the flow of the fluid.

[0090] The inner and outer body portions are held in place using optional pins (10).

[0091] An O-ring (11) is disposed between the inner and outer body portions to provide sealing against, for example, external fluids.

[0092] Fluid flow openings (5) are provided through both the inner and outer body parts (26, 27). A pipe connection piece (12) provides an example protective element disposed within the opening (27) in the outer body part, and optionally also within the opening (26) in the inner body part, to protect the outer body part from corrosive fluids within the opening. A seal ring (13) is provided between the pipe connection piece (12) and the inner body part. The pipe connection piece (12) is connected at its radially extending end to the outer body part using an optional plate (14) and screws (15). A pipe can be connected to the outer end of the pipe connection piece (12). The openings (26, 27) in the inner and outer body parts, respectively, are aligned with each other to provide fluid flow openings (5) through the valve body.

[0093] A seat connection piece (16) is provided to hold the inner body part in place within the outer body part. The seat connection piece is attached or joined to the outer body part of the valve, in this example using a seat flange (17) and bolts and nuts (18, 19). The seat connection piece (16) includes a flange (20) for connection to a pipe.

[0094] In the example embodiment, the seat connection piece (16) and seat flange (17) can be removed and the inner body part (3) (which is an integral metal piece) can exit the recess (28) of the outer body part (4) through an opening in the outer body part on the side where the seat flange (17) is located (the right side in the figure) after removing the pipe connection piece (12), which in the example embodiment protrudes into the opening (26) in the inner body part after proper removal of the stem (25).

[0095] The valve includes a valve seat (21) configured for sealing contact with the adjustment stem, and in particular for sealing contact with the plug. The valve seat includes a notch extension (23) for mating with the plug.

[0096] The adjustment stem is in this example attached at one end to an actuator, for example using a screw 22. Alternatively, the valve can be manually operated.

[0097] The valve also includes a leak detection element (29), which is optional and is provided to detect even the slightest leakage of fluid from the inner body portion to the outer body portion.

[0098] FIG. 3 shows a view from U of the valve of FIG.

[0099] FIG. 4 shows a view from V of the valve of FIG.

[0100] FIG. 5 shows a view along the line AA (see FIG. 4) of the valve of FIG.

[0101] FIG. 6 shows an isometric view of the valve of FIG.

Claims

1. A valve (1) for regulating the flow of a fluid, comprising a valve body (2), an inlet for a fluid, an outlet for a fluid, a flow regulating member (8), a chamber (7) for receiving a fluid within said valve body, and a valve seat (21), said valve body comprising an outer body portion (4) and an inner body portion (3) which are mated with each other and / or mechanically joined to each other, 1. A valve (1), wherein the outer body portion is made of a first material and the inner body portion is made of a second material, the first and second materials being different from one another, the inner body portion including a surface exposed to the chamber and in direct contact with the fluid in the chamber during operation.

2. The valve of claim 1 , wherein the inner body portion is releasably retained within the outer body portion.

3. 3. A valve as claimed in claim 1 or 2, wherein the flow regulating member (8) comprises an adjusting stem or a stem (25) and a plug (24) arranged to move between at least two different positions in the chamber to regulate the flow of fluid, the stem extending through an opening (30) in the inner body portion provided with a stem packing (9).

4. A valve as claimed in any preceding claim, wherein the valve seat (21) is supported by and in direct contact with the inner body portion.

5. 5. A valve as claimed in any one of claims 1 to 4, wherein the valve comprises an opening (26) in the inner body part and an opening (27) in the outer body part, the openings being aligned with one another to allow fluid flow between the opening (26) in the inner body part and the chamber, the valve comprising a protective element (12) disposed within the opening (27) in the outer body part so as to cover the outer body part from exposure to fluid in the opening (27) in the outer body part, the protective element (12) optionally also extending through the opening (26) in the inner body part.

6. 6. A valve as claimed in claim 5, wherein the protective element is a tubular element inserted both in the opening (26) in the inner body part and in the opening (27) in the outer body part.

7. 7. A valve as claimed in any preceding claim, comprising a seat connection piece (16) attached to the outer body part by a releasable connection means, the seat connection piece (16) holding the inner body part in position within a recess in the outer body part.

8. 8. The valve of claim 7, wherein the seat connection piece (16) also holds the valve seat in place within the valve body.

9. A valve as claimed in any preceding claim, wherein the inner body portion is made from stainless steel.

10. 10. A valve as claimed in claim 9, wherein the inner body portion is made from duplex stainless steel and preferably the outer body portion is made from carbon steel.

11. 11. The valve of claim 9 or 10, wherein the stem, the plug, the valve seat, the protective element, and the inner body portion are made of duplex stainless steel.

12. 12. A valve as claimed in any preceding claim, wherein the inner body part is a sleeve that mates with the outer body part and fits through an opening in the outer body part, the outer body part including a recess for receiving the inner body part and for releasably retaining the inner body part within the outer body part.

13. A valve as claimed in any preceding claim, wherein the outer body portion is a single piece of metal and the inner body portion is a single integral part.

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