Seat structures and flow control devices

Abstract

A flow control device (100) comprising a diaphragm (103) and a removable seat structure (120') for regulating the flow of fluid through a flow control device, the removable seat structure consisting of: a) a monolithic seat holder (105) wedged inside the flow control device and comprising; a holder inlet hole, and at least one holder outlet hole, and b) at least one seat (104) partially embedded in the monolithic seat holder and secured thereto, wherein the at least one seat each consists of a polymer protruding from the seat holder, the protruding being both towards the diaphragm and away from the diaphragm, such as to essentially prevent passage of the fluid throughout the device when the diaphragm is pressed.

Description

[0001] SEAT STRUCTURES AND FLOW CONTROL DEVICES BACKGROUND

[0002] Fluid control devices such as valves regulate and manipulate the flow of gases and / or liquids (fluids) through pipework. They are used in homes as well as in industrial settings.

[0003] These flow control devices are found in various applications in processes, including bulk chemical manufacturing, oil refining, and the pharmaceutical and semiconductor industries.

[0004] Valves operate by opening to allow the flow of fluid and closing to stop the flow of fluid. The opening and closing mechanism may be operated by adjusting a diaphragm, gate or ball which is positioned above a fluid inlet hole that is created inside a valve “body”. In valves with a diaphragm, when pressure is applied to the diaphragm, it pushes against a circular seat in the body, surrounding an inlet, to prevent the fluid from flowing between the valve body and the rest of the device. Once the applied pressure is released, the diaphragm rises, allowing the fluid to flow through the device.

[0005] However, the closing of the valve is not absolute, and some fluid does get through, to different extents depending on the design of the valve and its components, in particular the seat. The seats are subject to wear from the operation of the valve and degrade with time and temperature and exposure to reactive materials.SUMMARY

[0006] According to one aspect, a flow control device comprising a diaphragm and a removable seat structure for regulating the flow of fluid through a flow control device is provided, the removable seat structure consisting of:

[0007] a) a monolithic seat holder wedged inside the flow control device and comprising; a holder inlet hole, and at least one holder outlet hole, and

[0008] b) at least one seat partially embedded in the monolithic seat holder and secured thereto,

[0009] wherein the at least one seat each consists of a polymer protruding from the seat holder, the protruding being both towards the diaphragm and away from the diaphragm, such as to essentially prevent passage of the fluid throughout the device when the diaphragm is pressed.

[0010] In some embodiments, the monolithic seat holder is made of metal and the polymer consists of PFA [perfluoroalkoxy alkane / s].

[0011] In some embodiments the PFA comprises perfluoro methyl vinyl ether.

[0012] The PFA may consist of perfluoro methyl vinyl ether.

[0013] The monolithic seat holder may be made of SS316L.

[0014] The metal may be passivated and / or electropolished.

[0015] In some embodiments the seat structure is overmolded.

[0016] In some embodiments the polymer is annealed.

[0017] In some embodiments the polymer is annealed at 150-305°C for 10 minutes to 3 hours. In some embodiments the polymer is annealed at 225-275°C for 10 to 30 minutes.In some embodiments each at least one seat has undergone a soaking time of 10 minutes per mm thickness of each at least one seat.

[0018] In some embodiments the seat holder comprises a plurality of injection holes extending throughout the seat holder and situated between the inlet hole and the at least one outlet hole.

[0019] Some embodiments are configured to allow receiving the polymer injected into the plurality of injection holes such that an overmold polymer is formed with a plurality of anchoring regions around the circumference of the holder inlet hole.

[0020] In some embodiments an overmold polymer is formed by injection molding.

[0021] In some embodiments a diameter of each of the plurality of injection holes is smaller than a diameter of each of at least one holder outlet hole.

[0022] In some embodiments there is at least one first ridge around a circumference of a bottom face of the seat holder, and there is at least one second ridge around a circumference of an upper face of the seat holder,

[0023] wherein a height of the at least one ridge on the bottom face of the seat holder is greater than the height of the at least one ridge on the upper face of the seat holder.

[0024] In some embodiments the diaphragm, when the flow control device is in a closed state, creates a seal with the at least one second ridge.

[0025] In some embodiments the seat holder further comprises undercuts which anchor the at least one seat.

[0026] In some embodiments the protruding towards the diaphragm is 0.3-0.5 mm.

[0027] According to another aspect, an improved method of manufacturing a seat structure for housing at least one seat inside a fluid flow control device is provided, the method comprising:selecting a metal disk which will firmly fit inside the flow control device; measuring a diameter of a body inlet hole in the flow control device:

[0028] drilling an inlet hole in the center of the metal disk with the same diameter as the diameter of the body inlet hole;

[0029] drilling at least one holder outlet hole in the metal disk;

[0030] partially embedding at least one polymer seat in the disk and securing the at least one seat thereto,

[0031] such that the at least one seat are each protruding from the disk, the protruding being both towards the diaphragm and away from the diaphragm, such as to essentially prevent passage of the fluid throughout the device when the diaphragm is pressed.

[0032] Some embodiments further comprise injection moldingthe polymer on the diskto create an overmolded seat holder.

[0033] Some embodiments further comprise:

[0034] drilling a plurality of injection holes between the inlet hole and the at least one outlet hole;

[0035] securing the seat holder inside an injection machine, and

[0036] injecting a molten polymer into the plurality of injection holes until the polymer is protruding from two opposite sides of the disk.

[0037] In some embodiments the seat structure has two seats, consecutively injection molded onto the disk.

[0038] Some embodiments further comprise annealing the injected polymer.

[0039] In some embodiments the annealing is at 150-305°C for 10 minutes to 3 hours.

[0040] In some embodiments the annealing is at 225-275°C for 10 to 30 minutes.

[0041] Some embodiments further comprise providing a soaking time of 10 minutes per mm thickness of each at least one seat.Some embodiments further comprise heatingthe disk durin the injection molding.

[0042] Some embodiments further comprise heatingthe disk duringthe annealing.BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The present disclosed subject matter will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which corresponding or like numerals or characters indicate corresponding or like components. Unless indicated otherwise, the drawings provide help in understanding the disclosure and embodiments as a whole and do not limit the scope of the disclosure. In the drawings:

[0044] Figure 1a shows a cross-sectional front view of a part of a prior-art flow control device, with a body situated below a diaphragm and equipped with a metal seat structure;

[0045] Figure 1 b shows a cross-sectional front view of a part of another prior-art flow control device, with a body situated below a diaphragm and equipped with a seat structure;

[0046] Figure 2a schematically shows a side cross-sectional front view of a novel overmold seat structure inside a flow control device, exhibiting a polymer overmold seat on a monolithic valve seat holder;

[0047] Figure 2b shows a side cross-section of another overmold seat structure [without the flow control device] exhibiting a polymer overmold seat on a seat holder;

[0048] Figure 2c shows a flow control device with an overmold seat structure, demonstrating that the seat holder is positioned below a diaphragm; the diaphragm is in an open state, thus allowing the fluid to flow through the device;

[0049] Figure 3 is an in-perspective photo top view of one seat structure embodiment before a seat polymer has been injected into a seat holder;

[0050] Figure 4a is a top cross-sectional view of a seat structure with an overmold seat, after the polymer has been injected into the seat holder;

[0051] Figure 4b is another [bottom cross sectional] view of the valve seat holder shown in Figure 4a after the seat polymer has been injected into the seat holder;

[0052] Figure 4c is an expanded view of the seat structure in the area of interface between the seat holder and the seat overmold;

[0053] Figure 5a is a top perspective view of another seat structure with two overmold seats, after the polymer has been injected into the seat holder, the seat holder is shown as transparent for illustration of the internal design of the seat structure;Figure 5b is another [side] view of the seat structure shown in Figure 5a after the seat polymer has been injected into the seat holder;

[0054] Figure 5c is top perspective view of the seat structure shown in Figure 5a;

[0055] Figure 6 schematically shows a side cross-sectional view of part of another flow control device, with two polymer ring seats secured inside a valve seat holder;

[0056] Figure 7 is a photograph in-perspective top view of a polymer ring used inside the two-seat valve seat holder, alongside a top view of half of a two-seat valve seat holder, and

[0057] Figure 8 is a photograph of a sectional top view the two-seat valve seat holder, highlighting the two polymer rings which are secured into a groove of a lip surrounding an inlet hole.

[0058] DETAILED DESCRIPTION OF EMBODIMENTS

[0059] The subject matter discussed in this section should be assumed to be something other than prior art merely due to its mention in this section. Similarly, a problem mentioned in this section or associated with the subject matter provided as background should not be assumed to have been previously recognised in the prior art. The subject matter in this section merely represents different approaches, which in and of themselves may also correspond to implementations of the claimed seat structures and fluid flow control devices and methods.

[0060] Fluid flow control devices, such as valves, are used to regulate the flow of liquids and gases (from now on, referred to as fluids). The devices have an inlet from which process fluid enters the device and an outlet from which the process fluid exits the device. A valve will open (to allow the fluid to flow) and close (to stop the flow of fluid). Some valves are operated using a diaphragm which is employed above a body inlet hole to open and close the valve.

[0061] Such valves include in their lower region a valve body that has a circular seat surrounding a body inlet hole. Pressing the diaphragm against this seat causes the valve to close.Some commercially available seats are metal-type. All wetted surfaces in such seats are metal. These seats generally have an excellent corrosive media compatibility and an excellent heated media compatibility. However, such seats generally have lower leak rate performance and lower life cycle performance when compared to a typical commercial soft seat design. The metal seat is typically welded and, therefore, is a permanent and irremovable part of the flow control device.

[0062] Commercially available soft seat designs of the “caulked seat design” have a seat pressed into the body. The design is simple. These seats have an excellent leak rate performance when compared to a metal seat design, and excellent life cycle performance when compared to a metal seat design. However, eventually they wear down, or the seat becomes misshapen, or gets contaminated, but can’t be rebuilt.

[0063] Valve seats and / or their holders are disclosed below that are replaceable, thus allowing to replace only seats that are contaminated or worn out and prevent replacing an entire flow control device.

[0064] In addition, these novel seat holders balance two crucial factors required for flow control devices, the elasticity within the valve which does not deform or become damaged under pressure, and strength, since there will be a lot of force applied to the valve seat from the diaphragm. Thus, it is critical that the valve seat is strong under compression The balance of these factors require a robust and reliable fluid valve seat.

[0065] The valves contemplated below may also need to have consistent, long-term low leakage and reactivity in adverse conditions such as elevated temperatures and aggressive gases and may be expensive to replace if they wear down. The embodiments described below can be rebuilt: The seat can be replaced without replacing the valve. The valve may have superior leak rate performance, and excellent life cycle performance when compared to a metal seat design.

[0066] Seat structures with polymeric seats are known. In high purity fluid applications, it is known by the skilled in the art that it is desirable to minimize the total amount ofpolymer material exposed to the controlled fluid. This goal of reducing polymer content may be achieved by creating an insert of polymer material inside the seat structure, having a relatively small volume, for example not protruding from the

[0067] structure. However, our approach is opposite, because our goal is to deliberately expose polymer material to the controlled fluid, to impart very high performance to our valves, l.e., the pressed diaphragm in our novel valves mainly or only contacts the polymerin the area immediately surrounding thefluid inlet.

[0068] Each novel seat structure embodiment comprises at least one polymeric seat. The seat structure is wedged in the device below the diaphragm and above a body inlet hole. The protruding seat is secured inside the monolithic seat holder before being placed in the valve. One advantage of utilising this seat structure is that it enables removing the seat from the device body rather than a seat which is permanently attached to the body of the flow control device. One purpose and ability of the novel seat structures

[0069] is to establish a tight seal around the device inlet and the diaphragm. Since a tighter seal reduces the likeliness of fluid leaking out, it is a more reliable flow control device.

[0070] Figure 1a and Figure 1b are drawings of prior art devices; these represent commercially available solutions for blocking and unblocking inlets of flow control devices.

[0071] Figure 1a shows a cross-sectional front view of a metal seat structure 300, with a metal seat 013 affixed to a body 009 of a flow control device, below a diaphragm 003.

[0072] Pressingthe diaphragm 003 against the seat 013 causes blockage of body inlet hole 019. Prior art seat structure 300 requires affixing the metal seat 013 to become part of the body 009, creating a durable solid seal with the diaphragm 003 that can withstand high temperatures. One drawback of this seat structure is that when switching from a first process fluid to a second process fluid purported to flow via the seat structure, the seat 013 can be a source of contamination of the second process fluid with the first process fluid. The seat 013 cannot be replaced, and therefore the whole device must be replaced. Another drawback is that metal seats have microscopic surface irregularities such as scratches that detract from the sealing ability of the seats and severely limit the maximum pressures under which the fluid can be blocked.Figure 1 b shows a cross-sectional front view of another prior art integrated seat structure 400, illustrating how a soft seat 011 is secured inside the body 009 of the flow control device below the diaphragm 003. The elastic seat forms a tight seal when the device is in a closed state, i.e., the diaphragm 003 contacts the soft seat 011. However, similar to the metal seat (Figure 1a), the integrated seat 400 cannot be repaired, and the entire flow control device will need to be replaced.

[0073] We now disclose novel flow control devices, each comprising a diaphragm, and a removable seat structure for regulating the flow of fluid through a flow control device, the removable seat structure consisting of:

[0074] c) a monolithic seat holder wedged inside the flow control device and comprising; a holder inlet hole,

[0075] at least one holder outlet hole,

[0076] at least one lip surrounding a circumference of the holder inlet hole, and

[0077] d) at least one seat partially embedded in the monolithic seat holder and secured thereto,

[0078] wherein the at least one seat each consists of a polymer protruding from the seat holder, the protruding being both towards the diaphragm and away from the diaphragm, such as to essentially prevent passage of the fluid throughout the device when the diaphragm is pressed.

[0079] Some of the novel seat structure embodiments are overmolded. Some of the novel seat structures are not overmolded, for example seats are prepared in advance in their final form and partially inserted into seat holders, as will be demonstrated below. Typically, when the novel seat structures are overmolded, polymeric materials are injected onto / into seat holders to create the seat structures.

[0080] The seat holders and seats may be made in various geometries and sizes. Some overmolded seat structures have a seat holder that comprises a plurality of small injection holes extending throughout the holder and situated between an inlet hole and at least one outlet hole in the holder.These small injection holes may accommodate the overmolded polymer, which is injected into them. The process fluid does not pass through the injection holes, which are filled with the seat after the injection is completed, and thus the holes can be considerably smallerthan the outlet holes.

[0081] Generally, the novel overmolded seat structures include an overmold polymer that is formed by injection molding. However, in some embodiments molding is not entirely or at all performed via injection holes in the seat holder. For example, in some embodiments, polymer may be laid on various sides of the seat holder, for example quickly and simultaneously laid thereon and / or therein. On one hand, such actions may be difficult to perform. However, on the other hand, the actions may provide seats that are relatively uniform, as compared for example to laying one seat by one relatively prolonged and non-uniform injection.

[0082] We now refer to Figure 2a, Figure 2b, Figure 2c and Figure 3. Figure 2a schematically shows a side cross-sectional front view of a seat structure 120’ inside a flow control device 100, exhibiting a polymer overmold seat 104 on the seat holder 105. Figure 2b shows a cross-section side view of another embodiment 120”, exhibiting a polymer overmold seat 104’ on the seat holder 105’. Figure 2c shows a seat holder 105’ inside a flow control device 100, positioned below a diaphragm 103 and above a body inlet hole 119. The diaphragm 103 is in an open state, allowingfluid to flowthrough the device.

[0083] The open state refers towhen the diaphragm is convex. When the device 100 is open, the diaphragm does not touch the seat structure, allowingfluid to enter the device 100. A closed state [not shown] signifies that the diaphragm is pressed down against the seat, thus creating a seal with the holder inlet hole and preventing fluid from entering the device.

[0084] Figure 3 is a photo in-perspective view of a seat holder 105’” before an overmold has been injected into the seat holder.Figure 4a is a top perspective cross-sectional view of a seat holder 105”” after overmold 104”” polymer has been injected into injection holes 107 of the seat holder. The overmold seat 104”” together with the seat holder 105”” are hereinbelow referred to as the overmold seat structure 120.

[0085] Figure 4b is a bottom cross-sectional view [upside down] of the valve seat holder 105”” after the polymer has been injection molded into the injection holes 107 of the valve seat holder 105””, showing the first ridge hbion the bottom face of the seat holder to ensure the fluid can exit the device through the holder outlet holes 106. In addition, the seat 104”” extends outwards from the injection holes, distally from the diaphragm 103 [i.e., from the bottom of the holder] such as to create a gasket between the body inlet hole 119 and the holder inlet hole 101.

[0086] The removable seat structure 120 is positioned above a body inlet hole 119 [Figure 2a], and a body outlet hole 102 of the flow control device, and below a diaphragm 103. The diaphragm 103 controls fluid flowthrough the device such that when pressure is applied to the diaphragm 103, the diaphragm forms a seal with the protruding overmolded polymer 104”” and prevents fluid from flowing through the device.

[0087] As used herein, the term “valve seat holder”, or simply just “seat holder”, refers to a monolithic disk inside the flow control device above the body inlet hole and body outlet hole of the device. The seat holder is configured to secure the respective body inlet hole and body outlet holes.

[0088] The term “monolithic seat holder” refers to a seat holder formed of a single piece of metal without joints, seams orseparable parts. The monolithic seat holder may be manufactured from a single unified body exhibiting consistent physical and mechanical properties throughout. The removable seat holder 105, 105’, 105”, 105”’, 105”” is usually constructed using metal to ensure its strength and durability. In particular, for applications such as exist in the semiconductor process industry, using abrasive fluids at high temperatures, SS316L may be used. SS316L is a low-carbon, austeniticchromium-nickel-molybdenum stainless steel offering superior corrosion resistance]. The "L" indicates low carbon (less than 0.03 % w / w ).

[0089] The monolithic seat holder 105”’, shown in Figure 3, features multiple types of holes drilled into the metal disk, with the largest hole at the centre, the holder inlet hole 101. The holder inlet hole 101 is the entry point for fluid into the device, while the small injection holes 107 are located on a lip 113surroundingthe holder inlet hole. The small injection holes may interchangeably be referred to as lip holes for this embodiment. These small injection holes 107 accommodate the overmolded polymer, which is injected into them. The outlet holes 106 are positioned around the outer edge of the seat holder disk 105”’, serving as the exit points forfluid from the device.

[0090] The monolithic seat holder 105’” may include at least one first ridge hbiextending around the circumference of the bottom face and at least one second ridge huiextending around the circumference of the upper face. In some embodiments, the height of the first ridge hbion the bottom face is greater than the height of the second ridge huion the upper face. This embodiment may improve the stability and sealing performance of the seat holder within the device. Around the circumference on the upper face of the seat holder 105’” there is a second ridge hui[see also Figure 2a]. Figure 2a shows how the diaphragm 103 creates a seal with second ridge huiwhen the device is in an open state. This seal ensures the fluid which enters the device only flows through the outlet holes 102 and not into the device above the diaphragm 103.

[0091] The monolithic seat holder will vary in size and maybe shape depending on the flow control device it is used in. However, the diameter of the seat holder dsi(including the ridge) is about the same as the diameter of the diaphragm ddi, shown in Figure 2a. The diameter of the seat holder dsiis about the same as the diameter of the diaphragm ddito a ensure that the fluid entering the device through the holder inlet hole only exits through the holder outlet holes.

[0092] When the diaphragm is convex and fluid is flowing, the edge of the diaphragm will form a seal with the second ridge huiof the seat holder, thereby preventing the fluid from escaping into the device. If the diameter of the diaphragm ddiis smaller than thediameter dsiof the seat holder, there will be space for the fluid to enter the device rather than flowthrough the outlet holes 102.

[0093] As used herein, the term “overmolded polymer,” refers to a molten polymer material that is injection-molded into the injection holes 107 of the valve seat holder and that conforms to contours of the holder 105”’. The injection holes 107 are configured to receive the overmolded polymer material and to form anchoring regions that retain the overmolded polymer.

[0094] The anchoring regions may be provided at multiple locations around the seat holder. In some embodiments, the spatial distribution of the anchoring regions contributes to the enhanced mechanical retention of the overmolded polymer and to the overall structural performance of the overmolded seat. For example, as shown in Figure 4c, the anchoring regions may include an upper anchoring region 115a and a bottom anchoring region 115b.

[0095] The overmolded seat may comprise a polymer that protrudes from the seat holder, with the protrusions extending both towards and away from the diaphragm. These protrusions are configured to interact with diaphragm, such that when the diaphragm is pressed, fluid passage through the device when the diaphragm is prevented.

[0096] During operation, the protruding seat may be exposed to abrasive fluids, elevated temperatures resulting from the fluid flowing through the device, and high pressure applied by the diaphragm. Consequently, fluoropolymers, in particular PFAs [perfluoroalkoxy alkane / s] are suitable materials for the protruding seat which can withstand these conditions. The PFA / s may comprise perfluoro methyl vinyl ether. In some embodiments, the PFA may consist of perfluoro methyl vinyl ether.

[0097] The overmolded polymer seat is strong and flexible, making it suitable for use at high temperature environments and in the presence of harsh or toxic process fluids.

[0098] Perfluoroalkoxy alkane (PFA) materials are advantageous due to their ability to maintain stable at elevated temperatures while remaining inert. In addition, injection moldingPFA as an overmolded component may reduce manufacture cost by minimising material waste.

[0099] PFA for injection molding is typically provided in pellet form. When heated, the pellets melt into a homogeneous material that can be injection-molded into the seat holder through the injection holes 107 [see Figure 3]. Duringthe injection molding process, the seat holder 105”’ is placed inside an injection molding machine, which secures the seat holder while the molten polymer is injected into the injection mold holes 107 and conforms with the shape and the contours of the holder 105”’.

[0100] The molten polymer (PFA) should fill all the injection holes 107 and forms a polymer layer of a desired thickness above and below the holes, thereby creating the overmold seat. After the polymer has cooled and set, the seat holder 105’” may be removed from the injection molding machine. Any excess polymer may be removed, and the completed overmold seat structure 120 may be installed inside the flow control device.

[0101] One benefit of injection molding for constructing this overmolded polymer component of the valve, is increased accuracy. Creating seats by cutting of cylinders is difficult and tends to be imprecise because of difficulty working with the very small dimensions and considerable heating of the polymer duringthe cutting. The machine can duplicate the same complex shapes without human interference and error. Another benefit of injection molding is that the injection mold is made from a single piece of plastic. After the pellets are melted, they turn into a viscous substance that solidifies into one component. As this component covers both the upper and lower faces of the seat holder in the shape of a double gasket, the likelihood of part or all of the overmolded polymer falling off is reduced.

[0102] A high elasticity of the overmolded polymer seat is an important factor. The elasticity is beneficial as it reduces the likelihood that the polymer seat will irreversibly deform when under pressure.In some seat structure and manufacture embodiments, annealing may be performed right after the injection to strengthen the polymer after the injection molding and produce a more uniform seat. Annealing involves an intentionally reduced rate of cooling of the molten polymer. The annealing may release internal stress within the polymer resulting from the injection moulding and may improve the sealing properties and longevity of the seat.

[0103] At present we believe that the polymer should be annealed at 150-305°C for 10 minutes to 3 hours.

[0104] More particularly, the polymer may be annealed at 225-275°C for 10 to 30 minutes.

[0105] During annealing, each at least one seat may individually undergo a soaking time of 10 minutes per mm thickness, wherein the thickness may be defined the maximum distance between opposite sides of the seat, see for example the expanded view of a seat structure, shown in Figure 4c: the sides 111a, 111b of the seat are circular surfaces that are considered herein to be the opposite sides. Note that upper side 111a in this particular embodiment is irregular. The thickness 113 is shown. The upper side 111a in this embodiment has a flat part at the top which is essentially parallel to the bottom side 111b. However, other embodiments are contemplated wherein the upper side and / or bottom side have no straight part or the straight part is not most distant from the other side.

[0106] We have found to our surprise that passivation of the metal of the monolithic seat holder before the injections take place may be significantly beneficial to the sealing properties of the overmolded seat.

[0107] Further improvement in valve performance was found to our surprise when the monolithic seat holder was electropolished before the injections takes place.

[0108] In some embodiments both passivation and electropolishing are performed on the seat holder. In some other embodiments only one of the steps is performed. At present we believe that both can be performed on the same holder with good results. Thesepretreatments of the metal seat holder [prior to injection] surprisingly appears to beneficially affect the structure of the injected seat according to our tests.

[0109] Such improvement is borne out for example in improved results in ageing testing, wherein the seat is subject to a mechanical load, for example an actuator pressing a diaphragm against the seat for an extended period of time, for example 24 hours, at elevated temperatures, for example 225°C. The thickness of the seat may be measured before and after the test to determine the ageing.

[0110] The seat holder itself may be heated while the injection takes place. In some embodiments the heating system includes means to provide for localized heating. For example, a plurality of electrical elements may be placed at various places on, in or near the seat holder and / or the seat, before and / or during the injection, to help minimize temperature gradients between the seat and the seat holder, and / or inside the seat itself, because the temperature gradients are currently believed to negatively affect the valve performance.

[0111] Figure 3 presents three categories of holes on the seat holder 105”’. The first is the holder inlet hole 101, which has the largest diameter, du. Then, there are the holder outlet holes, 106, with smaller diameters, doi, than the holder inlet hole diameter du. The smallest holes are those used for the overmold 107, with a diameter dmi. The different holder inlet hole and outlet hole diameters ensure the flow through the device is at a constant and high rate.

[0112] The number of holder outlet holes 106 on each seat holder 105”’ may vary depending on the size of the seat holder 105’” and the diameter of the holder inlet hole du. The ratio of the diameter dnof the holder inlet hole to the diameters doiof holder outlet holes may be considered when determiningthe number of holder outlet holes 106 drilled into each seat holder 105’” to maintain a constant high flow rate. The quantity of holder outlet holes doion the seat holder 105’” may be inversely proportional to a ratio of the diameter doiof the plurality of each of holder outlet holes to the diameter dn of the single holder inlet hole.Figures 4a, 4b and 4c depict another seat structure embodiment 120”” with a seat holder 105”” that does not have a lip with injection holes. Instead, the holder 105”” has edges 116a, 116b surrounding holder inlet hole 101””, which is where the fluid comes into the flow control device, and circular grooves 117a, 117b having the edges 116a, 116b as their inner walls. On the body of the seat holder disk there are numerous smaller, medium sized holes; these are the outlet holes 106, typically larger than the injection holes 107. Since these may be physically smaller than the holder inlet hole, multiple outlet holes may be used to ensure that all the fluid that flows into the device can flow at high rate.

[0113] In this embodiment, there is only one single holder inlet hole, the reason being that if there were to be more than one holder inlet hole, then when the process fluids enter the device there would be an increased chance of cross-contamination between different inlet fluids. Another reason for having a single holder inlet hole is because of the diaphragm. When the diaphragm is closed, i.e. no fluid flows into the device, the diaphragm is concave or essentially flat. The concave shape allows the diaphragm to form a tight seal with a single holder inlet hole. However, if there were to be multiple holder inlet holes, then the concave shape might not effectively seal the multiple holder inlet holes.

[0114] Figures 4a and 4b present the first and second ridges hbiand huirespectively, which are located around the circumference of the seat holder. The ridge hbion the bottom face of the seat holder may be greater than the ridge huion the upper face of the seat holder. The ridge hbiensures that all the process fluid which enters the flow control device can exit at a high rate. As mentioned previously the holder inlet hole 101 has a greater diameter dii than the diameter of the outlet holes doiand forthat reason, more outlet holes 106 are required to ensure the flow is consistent. Since the flow control device only has one outlet but multiple outlet holes 106 the first ridge hbion the seat holder allows for all the outlet holes 106 to be connected to the device outlet. Therefore, the overmolded polymer seat 104”” is on both sides of the holder inlet hole 101 on the seatholder 105”” to ensure a tight seal and prevent the process fluid from re-entering the flow control device.

[0115] The overmold seat structure allows for easy replacement in the event that the overmold seat or the seat holder becomes damaged. Since the seat structure is formed as a removable disk, it can be easily removed from the flow control device and repaired or replaced without requiring replacement of the entire device. The ease of replacement also reduces the risk of contamination when the process fluids are changed and enables the same flow control device to be reused with different overmolded seat structures.

[0116] The flow control device is designed to allow the valve seat holder to be removed and replaced while remaining securely retained during operation. In use, the valve seat holder is fitted firmly inside the flow control device to prevent movement or displacement, and to contain the processed fluid, thereby reducingthe likelihood of leakage between the seat holder and the device. The seat holder is held in place inside the flow control device primarily by pressure, eliminating the need for mechanical attachment methods. The removable seat structure is pressure-held within the flow control device and is removable without causing damage to the seat structure, diaphragm, or the fluid control device.

[0117] In order to ensure proper fit within the control flow device, the dimensions of valve seat holders may vary depending on the device configuration.

[0118] For example, when manufacturingthe monolithic seat holder from the metal disk, the diameter of the holder inlet hole may be determined by measuringthe diameter of the body inlet hole 119 of the corresponding flow control device. Accordingly, a holder inlet hole of appropriate size may be drilled in a metal disk.

[0119] In this embodiment, device 100, no small elements need to be specifically constructed for the overmold, increasing production ease and efficiency.Figures 5a, 5b, 5c depict another overmolded seat structure 320, this embodiment having two separate seats 304a, 304b.

[0120] The seats 304a, 304b may be simultaneously injected or sequentially injected.

[0121] Typically they will be sequentially injected to simplify the preparation.

[0122] To help stabilize the form and position of the seats 304a, 304b, one or more of them may have a region that is wedge-shaped. The seat holder 305 includes therein undercuts 323 into which the molten polymer of the seats 304a, 304b is injected and conforms therewith to create the wedges 321 which anchor the seats 304a, 304b.

[0123] Alternatively, other seat holder embodiments have other features that help the seats be anchored and retain form under pressure at elevated temperatures such as at 200-220°C.

[0124] In general, the seat holder may appear as a monolithic body with a generally circular profile and multiple lobed extensions around its periphery. The internal surfaces may show machined features including stepped or grooved regions along the inner circumference. The monolithic seat holder may be configured to receive and secure polymer seat components through its internal geometry while providing fluid flow pathways between the inlet hole and outlet holes positioned around the structure. The seat structure may include cylindrical support structures or posts that may extend between the upper and lower surfaces of the seat holder. These support structures may provide structural reinforcement. The design may incorporate various ridges and surfaces at different heights, which may facilitate sealing engagement with a diaphragm when the flow control device is in operation.

[0125] It is notable that even PFA loses some elasticity at the elevated temperatures and becomes more plastic. For such conditions and with the depicted embodiment we have found that the top seat 304a should protrude from the seat holder [measured from the adjacent holder surface] by 0.3-0.5mm ±20%, or ±10%. At present this depicted and described embodiment is considered as a best mode. The seat may protrude more, perhaps up to 1 mm. The ideal protrusion is a by-product of the exact manufacturedesign of the holder structure rather than a goal set in advance and requiring an appropriate design. The upper limit of protrusion aims to prevent excessive warping of the seat at high temperatures and pressure. The lower limit aims to prevent contact of the diaphragm with the seat holder over an extended period of time.

[0126] The seat holder is designed such that the pressed diaphragm contacts only the seat in the area of the holder inlet hole.

[0127] Figure 6 schematically shows a side cross-sectional view of another flow control device 200 with two polymer rings 210 secured inside a valve seat holder 205. The valve seat holder 205 is wedged inside the flow control device, below a diaphragm 203 and above a body inlet hole 219.

[0128] Figure 7 is a photographic in-perspective top view of a polymer ring 210 used inside the two-seat valve seat holder 205, alongside a top view of half of a two-seat valve seat holder 205, and

[0129] Figure 8 is a photographic sectional front view of a two-seat valve seat holder 205, highlightingthe two polymer rings 210, which are each secured into a groove 212 of a lip 213 surrounding a holder inlet hole 201.

[0130] By “polymer seat rings”, we refer to individually cut rings that will be secured on two sides of the seat holder surrounding the holder inlet hole. The polymer seat rings may be formed by casting / turning a polymer cylinder; then, the cylinder will be sliced / shaped into individual rings.

[0131] The seat rings may comprise a polymer protruding from the seat holder, with the protrusions extending both towards and away from the diaphragm. These protrusions are configured to substantially prevent fluid passage through the device when the diaphragm is pressed. The top side of the ring 210 will come into contact with the diaphragm 203 when it converges to close the valve, and the bottom ring will secure the inlet hole 201, preventing the process fluids from mixing by securing the circumference of the holder inlet hole 201.The polymer used to construct these rings can be the same as the polymer used in the overmold embodiment since it can be melted and molded into the desired shape. In this case, the polymer may be provided as a pipe, the inside diameter of the polymer seat ring dpwill be bigger than the diameter di2of the holder inlet hole. The pipe will then be cut into the individual rings for the seat.

[0132] The two polymer rings 210 are used on the upper and lower faces of the seat holder. Two individual polymer rings on either side of the seat holder compared to one ring or cylinder therethrough may increase the elasticity of the rings, enabling them to be compressed and not deform, thus increasing the efficiency of the seat holder and reducing the rings’ deformation under higher fluid temperatures. If there were to be one ring through the whole seat holder, the polymer would be more likely to deform under high temperatures and greater forces, and thus be less effective.

[0133] Figure 7 shows the holder inlet hole diameter di2and the holder outlet holes diameter dO2. As can be seen from the figures, the diameter of the holder inlet hole di2is larger than the diameter of the holder outlet holes dO2. As a result, more outlet holes 206 are required to allow a higher flow rate through the device. The fluid flows through the holder inlet hole 201 into the device, from there, the fluid leaves the device through the numerous outlet holes 206 in the seat holder 205. There is only one outlet pipe in the body of the device; therefore, all the outlet holes 206 lead to the same outlet pipe. The bottom face of the seat has a larger ridge to allow the fluid to flow around the outlet holes to the outlet pipe while the diaphragm is closed. This ridge is labelled as hb2 in Figure 8.

[0134] Figure 8 shows the seat holder 205 with the upper polymer ring 210 cut. In this embodiment the lip 213 around the holder inlet hole has a groove 212 in it, this groove 212 is on each of both faces of the seat holder. The groove 212 is where the polymer rings 210 are secured into the seat holder 205. These grooves 212 form a ‘H’ shape in the cut-out view of the seat holder, which illustrates how the seat holder 205 separatesthe two rings 210. This side angle view also shows how the edges of the groove 212 bend slightly inwards to crimp each of the polymer rings 210 in place.

[0135] Within this embodiment, seat structure 200, the monolith two-seat valve seat holder 205 has the holder inlet hole 201 and the set of holder outlet holes 206. This seat structure has ‘H'-shaped edges, resulting from the lip grooves 212 on both faces, which hold the polymer ring 210 in place. Consequently, the structure 200 doesn’t require injection holes, which in other embodiments are used for injection molding.

[0136] As mentioned above, seat holder 205 is easily removable from the flow control device, without damaging the diaphragm or the fluid device. Thus, replacing or fixing the two-seat holder 200 is possible without replacing the whole flow control device. This flexibility is beneficial as it prevents cross-contamination for example when changing the process fluids used within the flow control device. In this embodiment, if one of the polymer rings 210 may be damaged, it may be possible to remove a single ringto replace it.

[0137] The two seat monolithic seat holder 205 is wedged below the diaphragm 203 and above the body inlet hole 219. The removable monolithicseat holder 205 isn’t fastened or secured to the body of the flow control device. When the device 200 is in an open state the diaphragm 203 is convex, so the fluid flows in through the holder inlet hole 201 and then out through the holder outlet holes 206. When the device is in a closed state the diaphragm 203 is concave or essentially flat and forms a tight seal around the top of the holder inlet hole 201 , preventing any fluid from entering the device. To facilitate the tight seal, the diameter of the seat holder dS2 is about the same as the diameter of the diaphragm dd2, shown in Figure 6.

[0138] The monolithic seat holder 205 may include at least one first ridge hb2 extending around the circumference of the bottom face and at least one second ridge hU2 extending around the circumference of the upper face. In some embodiments, the height of the first ridge hb2 on the bottom face is greater than the height of the second ridge hU2 on the upper face. This design can improve the stability and sealing performance of the seatholder within the device. The diaphragm 203, when in an open state, forms a seal with the second ridge hU2 of the monolithicseat holder, preventing the fluid from escaping and maintaining the constant high fluid flow out of the outlet holes 206. The polymer rings 210, inside the lip groove 212, on both faces of the monolithic seat holder 205, ensure the seals around the holder inlet hole 201 and the diaphragm 203 are tight. The polymer material is elastic thus it does not deform under the pressure applied by the diaphragm. In addition, there is a small volume between the seat holder and the valve body, defined by the first ridge, into which the seat on the bottom side of the holder [distal to the diaphragm] can beneficially be able to spread into when subject to pressure. This design of the ridges may be incorporated in any of the novel seat structures described herein.

[0139] The monolithic seat holder 205 and seats 210 are together defined as a removable seat structure 220.

[0140] The internal geometry of the valve body may show a weir-type configuration [not shown] where fluid flows upward over a raised portion before exiting through the outlet passage. When the device is in an open state, the diaphragm may be convex, so the fluid flows in through the holder inlet hole and then out through the holder outlet holes. In some embodiments, the flow control device may include a weir-type flow configuration where fluid may flow upward over a raised portion within the valve body before exiting through the outlet passage.

[0141] Clauses: Clause 1. A flow control device comprising a diaphragm and a removable seat structure for regulating the flow of fluid through a flow control device, the removable seat structure consisting of:

[0142] a) a monolithic seat holder wedged inside the flow control device and comprising; a holder inlet hole, and at least one holder outlet hole, and

[0143] b) at least one seat partially embedded in the monolithic seat holder and secured thereto,

[0144] wherein the at least one seat each consists of a polymer protruding from the seat holder, the protruding being both towards the diaphragm and away from the diaphragm,such as to essentially prevent passage of the fluid throughout the device when the diaphragm is pressed.

[0145] Clause 2. The seat structure of clause 1 , wherein the monolithic seat holder is made of metal and the polymer consists of PFA [perfluoroalkoxy alkane / s].

[0146] Clause 3. The seat structure of clause 2, wherein the PFA comprises perfluoro methyl vinvl ether.

[0147] Clause 4. The seat structure of clause 2, wherein the PFA consists of perfluoro methyl vinvl ether.

[0148] Clause 5. The seat structure of any one of clauses 1 to 4, wherein the monolithic seat holder is made of SS316L.

[0149] Clause 6. The seat structure of any one of clauses 2 to 5, wherein the metal is passivated.

[0150] Clause 7. The seat structure of any one of clauses 2 to 5, wherein the metal is electropolished.

[0151] Clause 8. The seat structure of any one of clauses 2 to 5, wherein the metal is both passivated and electropolished.

[0152] Clause 9. The seat structure of any one of clauses 1 to 8, wherein the seat structure is overmolded.

[0153] Clause 10. The seat structure of clause 9, wherein the polymer is annealed.

[0154] Clause 11. The seat structure of clause 10, wherein the polymer is annealed at 150-305°C for 10 minutes to 3 hours.Clause 12. The seat structure of clause 11 , wherein the polymer is annealed at 225-275°C for 10 to 30 minutes.

[0155] Clause 13. The seat structure of any one of clauses 10 to 12, wherein each at least one seat has undergone a soaking time of 10 minutes per mm thickness of each at least one seat.

[0156] Clause 14. The seat structure of any one of clauses 1 to 13, wherein the seat holder comprises a plurality of injection holes extending throughout the seat holder and situated between the inlet hole and the at least one outlet hole.

[0157] Clause 15. The seat structure of clause 14, configured to allow receiving the polymer injected into the plurality of injection holes such that an overmold polymer is formed with a plurality of anchoring regions around the circumference of the holder inlet hole.

[0158] Clause 16. The seat structure of any one of clauses 9 to 15, wherein an overmold polymer is formed by injection molding.

[0159] Clause 17. The seat structure of clause 14, wherein a diameter of each of the plurality of injection holes is smaller than a diameter of each of at least one holder outlet hole.

[0160] Clause 18. The seat structure of any one of clauses 1 to 17,

[0161] wherein there is at least one first ridge around a circumference of a bottom face of the seat holder, and there is at least one second ridge around a circumference of an upper face of the seat holder,

[0162] wherein a height of the at least one ridge on the bottom face of the seat holder is greater than the height of the at least one ridge on the upper face of the seat holder.

[0163] Clause 19. The seat structure of clause 18, wherein the diaphragm, when the flow control device is in a closed state, creates a seal with the at least one second ridge.Clause 20. The seat structure of any one of clauses 1 to 19, wherein the seat holder further comprises undercuts which anchor the at least one seat.

[0164] Clause 21. The seat structure of any one of clauses 1 to 20, wherein the protruding towards the diaphragm is 0.3-0.5 mm.

[0165] Clause 22. An improved method of manufacturing a seat structure for housing at least one seat inside a fluid flow control device, the method comprising:

[0166] selecting a metal disk which will firmly fit inside the flow control device; measuring a diameter of a body inlet hole in the flow control device:

[0167] drilling an inlet hole in the center of the metal disk with the same diameter as the diameter of the body inlet hole;

[0168] drilling at least one holder outlet hole in the metal disk;

[0169] partially embedding at least one polymer seat in the disk and securing the at least one seat thereto,

[0170] such that the at least one seat are each protruding from the disk, the protruding being both towards the diaphragm and away from the diaphragm, such as to essentially prevent passage of the fluid throughout the device when the diaphragm is pressed.

[0171] Clause 23. The method of clause 22, further comprising injection molding the polymer on the disk to create an overmolded seat holder.

[0172] Clause 24. The method of clause 23, further comprising:

[0173] drilling a plurality of injection holes between the inlet hole and the at least one outlet hole;

[0174] securing the seat holder inside an injection machine, and

[0175] injecting a molten polymer into the plurality of injection holes until the polymer is protruding from two opposite sides of the disk.

[0176] Clause 25. The method of clause 23, wherein the seat structure has two seats, consecutively injection molded onto the disk.

[0177] 1Clause 26. The method of any one of clauses 23-25, further comprising annealin the injected polymer.

[0178] Clause 27. The method of clause 26, wherein the annealing is at 150-305°C for 10 minutes to 3 hours.

[0179] Clause 28. The method of clause 27 , wherein the annealing is at 225-275°C for 10 to 30 minutes.

[0180] Clause 29. The method of any one of clauses 23 to 28, further comprising providing a soaking time of 10 minutes per mm thickness of each at least one seat.

[0181] Clause 30. The method of any one of clauses 23 to 29, further comprising heatingthe disk duringthe injection molding.

[0182] Clause 31. The method of any one of clauses 26 to 29, further comprising heatingthe disk duringthe annealing.

[0183] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments or example, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, example and / or option, may also be provided separately or in any suitable sub-combination or as suitable in any other described embodiment, example, or option of the invention. Certain features described in the context of various embodiments, examples and / or options are not to be considered essential features of those embodiments, unless the embodiment, example and / or option is inoperative without those elements.

[0184] While several examples have been described in detail, it is to be understood that the disclosed examples may be modified. Therefore, the foregoing description is to be considered non-limiting.While certain examples have been described, these examples have been presented by way of example only and are not intended to limit the scope of the disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the systems and methods described herein may be made without departing from the spirit of the disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.

[0185] Features, materials, characteristics, or groups described in conjunction with a particular aspect, or example are to be understood to be applicable to any other aspect or example described in this section or elsewhere in this specification unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The protection is not restricted to the details of any foregoing examples. The protection extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims and drawings), orto any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0186] Furthermore, certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable sub combination. Moreover, although features may be described above as acting in certain combinations, one or more features from a claimed combination can, in some cases, be excised from the combination, and the combination may be claimed as a sub combination orvariation of a sub combination.

[0187] Although the description uses terms “first,” “second,” etc. to describe

[0188] various elements, these elements should not be limited by the terms. These terms are only used to distinguish one element from another. For example, a first graphicalrepresentation could be termed a second graphical representation, and, similarly, a second graphical representation could be termed a first graphical representation, without departing from the scope of the various described embodiments. The first graphical representation and the second graphical representation are both graphical representations, but they are not the same graphical representation.

[0189] Moreover, while operations may be depicted in the drawings or described in the specification in a particular order, such operations need not be performed in the particular order shown or in sequential order, or that all operations be performed, to achieve desirable results. Other operations that are not depicted or described can be incorporated in the example methods and processes. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the described operations. Further, the operations may be rearranged or reordered in other implementations.

[0190] Those skilled in the art will appreciate that in some examples, the actual steps taken in the processes illustrated and / or disclosed may differ from those shown in the figures. Depending on the example, certain of the steps described above may be removed or others may be added. Furthermore, the features and attributes of the specific examples disclosed above may be combined in different ways to form additional examples, all of which fall within the scope of the present disclosure. Also, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products.

[0191] For purposes of this disclosure, certain aspects, advantages, and novel features are described herein. Not necessarily all such advantages may be achieved in accordance with any particular example. Thus, for example, those skilled in the art will recognize that the disclosure may be embodied or carried out in a mannerthat achieves one advantage or a group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.Conditional language, such as “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain examples include, while other examples do not include, certain features, elements, and / or steps. Thus, such conditional language is not generally intended to imply that features, elements, and / or steps are in anyway required for one or more examples or that one or more examples necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, and / or steps are included or are to be performed in any particular example.

[0192] Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, orZ. Thus, such conjunctive language is not generally intended to imply that certain examples require the presence of at least one of X, at least one of Y, and at least one of Z.

[0193] Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result.

[0194] Unless specifically stated otherwise, these terms are to be construed as up to ±10% of the stated value.

[0195] The scope of the present disclosure is not intended to be limited by the specific disclosures of preferred examples in this section or elsewhere in this specification and may be defined by claims as presented in this section or elsewhere in this specification or as presented in the future. The language of the claims is to be interpreted broadly based on the language employed in the claims and not limited to the examples described in the present specification or duringthe prosecution of the application, which examples are to be construed as non-exclusive.

Claims

CLAIMS:

1. A flow control device comprising a diaphragm and a removable seat structure for regulating the flow of fluid through a flow control device, the removable seat structure consisting of:a) a monolithic seat holder wedged inside the flow control device and comprising; a holder inlet hole, and at least one holder outlet hole, andb) at least one seat partially embedded in the monolithic seat holder and secured thereto,wherein the at least one seat each consists of a polymer protruding from the seat holder, the protruding being both towards the diaphragm and away from the diaphragm, such as to essentially prevent passage of the fluid throughout the device when the diaphragm is pressed.

2. The seat structure of claim 1 , wherein the monolithic seat holder is made of metal and the polymer consists of PFA [perfluoroalkoxy alkane / s].

3. The seat structure of claim 2, wherein the PFA comprises perfluoro methyl vinyl ether.

4. The seat structure of claim 2, wherein the PFA consists of perfluoro methyl vinyl ether.

5. The seat structure of any one of claims 1 to 4, wherein the monolithic seat holder is made of SS316L.

6. The seat structure of any one of claims 2 to 5, wherein the metal is passivated.

7. The seat structure of any one of claims 2 to 5, wherein the metal is electropolished.

8. The seat structure of any one of claims 2 to 5, wherein the metal is both passivated and electropolished.

9. The seat structure of any one of claims 1 to 8, wherein the seat structure is overmolded.

10. The seat structure of claim 9, wherein the polymer is annealed.

11. The seat structure of claim 10, wherein the polymer is annealed at 150-305°C for 10 minutes to 3 hours.

12. The seat structure of claim 11 , wherein the polymer is annealed at 225-275°C for 10 to 30 minutes.

13. The seat structure of any one of claims 10 to 12, wherein each at least one seat has undergone a soaking time of 10 minutes per mm thickness of each at least one seat.

14. The seat structure of any one of claims 1 to 13, wherein the seat holder comprises a plurality of injection holes extending throughout the seat holder and situated between the inlet hole and the at least one outlet hole.

15. The seat structure of claim 14, configured to allow receiving the polymer injected into the plurality of injection holes such that an overmold polymer is formed with a plurality of anchoring regions around the circumference of the holder inlet hole.

16. The seat structure of any one of claims 9 to 15, wherein an overmold polymer is formed by injection molding.

17. The seat structure of claim 14, wherein a diameter of each of the plurality of injection holes is smaller than a diameter of each of at least one holder outlet hole.

18. The seat structure of any one of claims 1 to 17,wherein there is at least one first ridge around a circumference of a bottom face of the seat holder, and there is at least one second ridge around a circumference of an upper face of the seat holder,wherein a height of the at least one ridge on the bottom face of the seat holder is greater than the height of the at least one ridge on the upper face of the seat holder.

19. The seat structure of claim 18, wherein the diaphragm, when the flow control device is in a closed state, creates a seal with the at least one second ridge.

20. The seat structure of any one of claims 1 to 19, wherein the seat holder further comprises undercuts which anchor the at least one seat.

21. The seat structure of any one of claims 1 to 20, wherein the protruding towards the diaphragm is 0.3-0.5 mm.

22. An improved method of manufacturing a seat structure for housing at least one seat inside a fluid flow control device, the method comprising:selecting a metal disk which will firmly fit inside the flow control device; measuring a diameter of a body inlet hole in the flow control device:drilling an inlet hole in the center of the metal disk with the same diameter as the diameter of the body inlet hole;drilling at least one holder outlet hole in the metal disk;partially embedding at least one polymer seat in the disk and securing the at least one seat thereto,such that the at least one seat are each protruding from the disk, the protruding being both towards the diaphragm and away from the diaphragm, such as to essentially prevent passage of the fluid throughout the device when the diaphragm is pressed.

23. The method of claim 22, further comprising injection molding the polymer on the disk to create an overmolded seat holder.

24. The method of claim 23, further comprising:drilling a plurality of injection holes between the inlet hole and the at least one outlet hole;securing the seat holder inside an injection machine, andinjecting a molten polymer into the plurality of injection holes until the polymer is protruding from two opposite sides of the disk.

25. The method of claim 23, wherein the seat structure has two seats, consecutively injection molded onto the disk.

26. The method of an one of claims 23-25, further comprising annealingthe injected polymer.

27. The method of claim 26, wherein the annealing is at 150-305°C for 10 minutes to 3 hours.

28. The method of claim 27, wherein the annealing is at 225-275°C for 10 to 30 minutes.

29. The method of any one of claims 23 to 28, further comprising providing a soaking time of 10 minutes per mm thickness of each at least one seat.

30. The method of any one of claims 23 to 29, further comprising heatingthe disk duringthe injection molding.

31. The method of any one of claims 26 to 29, further comprising heatingthe disk duringthe annealing.

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