Three valve group and differential pressure transmitter

Abstract

This application relates to a three-valve manifold and a differential pressure transmitter. The three-valve manifold for a differential pressure transmitter includes: a valve body, within which a first chamber and a second chamber are formed; the valve body is provided with a first measuring medium interface and a first transmitter interface leading to the first chamber, and a second measuring medium interface and a second transmitter interface leading to the second chamber; and a valve stem assembly including a valve stem extending into the valve body, the valve stem being movable longitudinally therein to connect or disconnect the first chamber and the second chamber; wherein the first measuring medium interface and the second measuring medium interface are located on the same side of the valve body and are arranged transversely relative to the longitudinal axis of the valve stem. The three-valve manifold proposed in this invention has advantages such as simple structure, convenient installation, reliable sealing, and low manufacturing cost, and is particularly suitable for miniaturized micro differential pressure measurement applications.

Description

Technical Field

[0001] This invention relates to the field of fluid measurement technology, and more particularly to a three-valve manifold for a differential pressure transmitter and a differential pressure transmitter equipped with the three-valve manifold. Background Technology

[0002] Differential pressure transmitters are the main instruments used in industrial fields to measure parameters such as differential pressure and liquid level. They contain sensitive sensing elements. In order to protect the sensing elements and avoid damage when instantaneous high pressure or high differential pressure occurs, a three-valve manifold is introduced to be used in conjunction with the differential pressure transmitter.

[0003] According to existing technology, this three-valve manifold has three valves: a high-pressure valve and a low-pressure valve, usually located on both sides of the valve body, and a balancing valve located in the middle of the valve body. By controlling the opening and closing of the three valves, the opening and closing of the corresponding fluid channels are controlled. The high-pressure valve and the low-pressure valve are used to open or close the high-pressure and low-pressure measurement channels of the differential pressure transmitter, respectively, while the balancing valve is used to control the connection or disconnection between the high-pressure measurement channel and the low-pressure measurement channel.

[0004] Currently, the three-valve manifolds commonly used in differential pressure transmitters on the market are assembled from machined metal parts such as stainless steel. Their structure is relatively complex, especially with numerous sealing mechanisms, resulting in high costs and a tendency for leakage during use. Furthermore, the large size of known three-valve manifolds makes optimized connection with differential pressure transmitters difficult, leading to inconvenience in installation and commissioning. These drawbacks are even more pronounced when these three-valve manifolds are used in micro-differential pressure measurement applications. Summary of the Invention

[0005] The purpose of this invention is to provide a three-valve manifold and a differential pressure transmitter to at least partially overcome the deficiencies in the prior art. In particular, the three-valve manifold has a simple and compact structure, small size, is easy to install and match flexibly, and can be manufactured with simple processes, significantly reducing manufacturing costs.

[0006] According to a first aspect of the present invention, a three-valve manifold for a differential pressure transmitter is provided, comprising: a valve body having a first chamber and a second chamber formed therein, the valve body having a first measuring medium interface and a first transmitter interface leading to the first chamber, and a second measuring medium interface and a second transmitter interface leading to the second chamber; and a valve stem assembly including a valve stem extending into the valve body, the valve stem being movable longitudinally therein to connect or disconnect the first chamber and the second chamber. The first measuring medium interface and the second measuring medium interface are located on the same side of the valve body and are arranged transversely relative to the longitudinal axis of the valve stem.

[0007] According to the present invention, the first and second measuring medium interfaces are located on the side of the valve body, relative to the longitudinal direction of the valve stem, and are situated on the same side of the valve body. This layout results in a simple and compact overall structure for the three-valve manifold, facilitating its use with differential pressure transmitters. Furthermore, through appropriate valve body design, the three-valve manifold offers numerous advantages, including convenient installation, reliable sealing, and low manufacturing costs.

[0008] Preferably, according to an embodiment of the present invention, the first chamber may be constructed as a first circular hole, the second chamber may be constructed as a second circular hole, the first circular hole and the second circular hole are interconnected through a central hole, and at least the first circular hole is coaxial with the central hole.

[0009] According to one embodiment of the present invention, the first circular hole includes an end hole section opening to the first end face of the valve body and a bottom hole section connected to the center hole. The valve stem extends into the valve body from the first end face of the valve body and is axially movable in the first circular hole to close or release the center hole opening located on the bottom surface of the bottom hole section.

[0010] Here, according to one embodiment of the present invention, the first measuring medium interface and the first transmitter interface are connected to the bottom hole section of the first circular hole at least when the central hole opening is released.

[0011] According to one embodiment of the invention, the valve stem includes a pusher head adapted to engage with the central bore opening to close or release the opening.

[0012] Preferably, the bottom surface of the bottom section of the first circular hole is flat, and the top head has a conical structure.

[0013] According to one embodiment of the present invention, the valve stem is provided with an operating mechanism at one end opposite to the top head, through which the valve stem can be operated from outside the valve body.

[0014] According to one embodiment of the present invention, the valve stem includes a guide shaft section, and the first circular hole includes a guide hole section between an end hole section and a bottom hole section. The guide shaft section is adapted to cooperate with the guide hole section to guide the axial movement of the valve stem in the first circular hole.

[0015] Furthermore, the guide hole section of the first circular hole is constructed as a threaded hole section with internal threads, and the guide shaft section of the valve stem has an external thread that matches the internal thread, thereby enabling the valve stem to move axially in the first circular hole by screwing it in or out.

[0016] According to one embodiment of the present invention, the valve stem includes a sealing shaft section, and a sealing mechanism is provided between the outer periphery of the sealing shaft section and the inner wall of the end hole section of the first circular hole for sealingly closing the opening of the first circular hole located on the first end face of the valve body to prevent medium leakage.

[0017] Preferably, the sealing mechanism includes a groove formed on the outer periphery of the sealing shaft section and a sealing ring embedded in the groove. This achieves a low-cost, simple, and reliable radial seal.

[0018] According to one embodiment of the present invention, the first circular hole, the central hole, and the second circular hole form a through hole extending from the first end face to the second end face of the valve body. Therefore, since the main channel inside the valve body adopts a straight-through structure design, it can be manufactured using a simple process.

[0019] Furthermore, the second circular hole includes an end hole section opening into the second end face of the valve body, in which a plug is detachably installed. Preferably, the plug is capable of sealingly closing the opening of the second circular hole located on the second end face of the valve body.

[0020] Furthermore, the end section of the second circular hole is constructed as a threaded section with internal threads, and the plug is constructed as a screw plug with external threads that match the internal threads. Preferably, a sealing washer, particularly an elastic sealing washer, is provided between the head of the screw plug and the second end face of the valve body. In this way, a low-cost and simple, reliable end-face seal can be achieved, and the sealing force can also be adjusted based on the screw tightening force.

[0021] Furthermore, the second circular hole includes a bottom hole section connected to the central hole, and the second measuring medium interface and the second transmitter interface are connected to the bottom hole section.

[0022] According to one embodiment of the present invention, the first transmitter interface and the second transmitter interface are disposed on the side of the valve body opposite to the first measuring medium interface and the second measuring medium interface. Accordingly, based on the interface layout scheme proposed in this invention, combined with the main channel straight-through structure design described above, all channels of the valve body can extend in only two directions (one is the longitudinal extension direction of the main channel from the first end face to the second end face of the valve body, and the other is the lateral extension direction of the interface channels from the side of the valve body into the interior), thereby enabling the valve body to be manufactured using simple processes and equipment, significantly reducing the cost of the three-valve assembly.

[0023] According to a second aspect of the invention, a differential pressure transmitter is provided, which is equipped with a three-valve manifold as described above.

[0024] Preferably, according to an embodiment of the present invention, the first measuring medium interface is used to introduce a low-pressure measuring medium, the second measuring medium interface is used to introduce a high-pressure measuring medium, the first measuring medium interface, the first chamber, and the first transmitter interface form a low-pressure measuring channel of the differential pressure transmitter, while the second measuring medium interface, the second chamber, and the second transmitter interface form a high-pressure measuring channel of the differential pressure transmitter.

[0025] According to one embodiment of the present invention, a first shut-off valve is provided at the first measuring medium interface or in the pressure-sensing pipeline connected thereto, and a second shut-off valve is provided at the second measuring medium interface or in the pressure-sensing pipeline connected thereto. Accordingly, based on the interface layout scheme proposed by the present invention, the shut-off valves can be flexibly designed and arranged according to specific equipment configurations, technical requirements, and installation conditions, and different types of valves, such as plug valves, piston valves, butterfly valves, etc., can be selected.

[0026] It goes without saying that the features and advantages of the three-valve manifold proposed in the first aspect of the present invention are also applicable to the differential pressure transmitter of the second aspect of the present invention. It is particularly worth mentioning that, according to some embodiments of the three-valve manifold of the present invention, compared with the prior art, in addition to the simpler and more compact overall structure of the three-valve manifold, making it easier to use with differential pressure transmitters, the valve body design is simplified to the greatest extent, enabling low-cost manufacturing with simple processes and equipment, while allowing for reasonable configuration and optimization of the sealing mechanism. Therefore, the present invention can realize a three-valve manifold for differential pressure transmitters that is simple in structure, small in size, easy to install and use, has fewer sealing components and reliable performance, reduces leakage risk and maintenance costs, and can be well matched to miniaturized micro-differential pressure measurement processes, providing users with a flexible and suitable field solution. Attached Figure Description

[0027] Exemplary embodiments of the invention are illustrated in the accompanying drawings. The embodiments and drawings disclosed herein should be considered illustrative rather than restrictive. It is also worth noting that, for clarity, some structural details in the drawings are not drawn to scale.

[0028] Figure 1 This is a schematic diagram of a three-valve manifold for a differential pressure transmitter according to one embodiment of the present invention. The diagram shows the first chamber (low-pressure measurement channel) and the second chamber (high-pressure measurement channel) being separated, with the valve stem in the position of closing the opening of the central hole.

[0029] Figure 2 This is a schematic diagram of a valve body according to one embodiment of the present invention;

[0030] Figure 3 This is a partial structural diagram of a valve body according to one embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of a valve stem according to one embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of a three-valve manifold according to one embodiment of the present invention. The diagram shows the first chamber (low-pressure measurement channel) and the second chamber (high-pressure measurement channel) in communication, with the valve stem positioned at the opening of the release center hole. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will now be described with reference to the accompanying drawings. Obviously, the described embodiments only relate to a portion of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the disclosed embodiments of the present invention without creative effort are within the scope of protection of this application.

[0034] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not specifically listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses. Those skilled in the art will understand that in the description of the specification and claims of this application, certain terms such as "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," "circumferential," "longitudinal," and "transverse," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings. They are merely for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device, mechanism, structure, or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting the invention.

[0035] The reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this term in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0036] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art and may be interpreted in the context of their application in the relevant technical description.

[0037] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0038] Figure 1-5 A schematic diagram of the structure of the three-valve manifold for a differential pressure transmitter of the present invention, including its valve body and valve stem, is shown.

[0039] This invention provides a three-valve manifold for a differential pressure transmitter, such as... Figure 1 and Figure 5 As shown, the three-valve assembly includes: a valve body 100, in which a first chamber and a second chamber are formed; the valve body is provided with a first measuring medium interface 102 and a first transmitter interface 105 leading to the first chamber, and a second measuring medium interface 101 and a second transmitter interface 104 leading to the second chamber; and a valve stem assembly 200, which includes a valve stem 201 extending into the valve body, the valve stem being movable longitudinally therein to connect or disconnect the first chamber and the second chamber. According to the invention, the first measuring medium interface and the second measuring medium interface are located on the same side of the valve body and are arranged laterally relative to the longitudinal axis of the valve stem. That is, the first measuring medium interface 102 and the second measuring medium interface 101 are located laterally on the valve body side relative to the longitudinal direction of the valve stem, and are located on the same side of the valve body, particularly as can be seen in [reference needed]. Figure 1 , Figure 2 , Figure 5 This layout allows for a simple and compact overall structure of the three-valve manifold, making it easy to use with differential pressure transmitters.

[0040] In the technical solution proposed in this invention, the relative positional relationship (i.e., intersection or transverse) between the valve stem orientation and the arrangement orientation of the two measuring medium interfaces is specified, as well as the relative positional relationship between the arrangement orientations of the two measuring medium interfaces (i.e., both are on the same side of the valve body). It can be understood that the above-mentioned "longitudinal", "transverse", "side" or "side" are merely relative concepts used to express positional relationships, and the specified relative positional relationships do not depend on any specific shape of the valve body itself.

[0041] Figure 2This is a schematic diagram of a valve body according to one embodiment of the present invention. The valve body 100 is, for example, a metal casting, and can be prismatic, such as a cuboid shape. In this case, the cuboid-shaped valve body defines two end faces and four side faces. The aforementioned "longitudinal" direction corresponds to the direction from the first end face to the second end face of the valve body, and the aforementioned "lateral" direction is the direction that intersects (or is transverse, preferably perpendicular) with the "longitudinal" direction. The valve body 100 can also be cylindrical. In this case, the cylindrical valve body defines two end faces and circumferential side faces. In this case, the aforementioned "longitudinal" direction corresponds to the direction from the first end face to the second end face of the valve body, that is, the "axial direction" of the cylinder, and the aforementioned "lateral" direction is the direction that intersects (or is transverse, preferably perpendicular) with the aforementioned "longitudinal" direction, that is, the "radial direction" of the cylinder.

[0042] According to one embodiment of the present invention, the first chamber may be configured as a first circular hole 300, and the second chamber may be configured as a second circular hole 103. The first circular hole 300 and the second circular hole 103 are interconnected through a central hole 107, and at least the first circular hole 300 and the central hole 107 are coaxial. Preferably, the second circular hole 103 is coaxial with both the first circular hole 300 and the central hole 107. This design is particularly beneficial for simplifying the tooling equipment and process operations during valve body manufacturing.

[0043] In this regard, it is worth noting that the second circular hole 103 does not necessarily have to be precisely coaxial with the first circular hole 300 and / or the center hole 107. It is only necessary to ensure that the center hole has openings that open to the first and second circular holes respectively, so as to connect the two.

[0044] Figure 3 This is a partial structural diagram of a valve body according to an embodiment of the present invention. As shown, the first circular hole 300 includes an end hole section 303 opening to the first end face of the valve body and a bottom hole section 301 connected to the central hole 107. The valve stem 201 extends into the valve body from the first end face and is axially movable within the first circular hole 300 to close or release the opening of the central hole 107 located on the bottom surface of the bottom hole section 301. When the opening of the central hole 107 is closed, the first chamber and the second chamber are isolated from each other, such as... Figure 1 As shown; when the central hole 107 is released, the first chamber and the second chamber are connected to each other, as shown. Figure 5 As shown.

[0045] Here, the first measuring medium interface 102 and the first transmitter interface 105 are connected to the bottom hole section 301 of the first circular hole 300 at least when the opening of the central hole 107 is released. This means that when the three-valve manifold of the present invention is used with a differential pressure transmitter, with the first chamber and the second chamber connected to each other, the high and low pressure measuring channels are also connected to each other, such as... Figure 5 As shown.

[0046] Figure 4 This is a schematic diagram of a valve stem according to one embodiment of the present invention. The valve stem 201 can be a machined metal part. As shown, the valve stem 201 includes a mandrel 211 adapted to engage with the opening of the central hole 107 to close or release the opening. According to one embodiment of the present invention, the bottom surface of the bottom hole section 301 of the first circular hole 300 is flat, and the mandrel 211 has a tapered structure. This mating structure is particularly advantageous for sealing the opening of the central hole 107 on the bottom surface of the bottom hole section 301.

[0047] According to one embodiment of the present invention, the valve stem 201 is provided with an operating mechanism 214 at one end opposite to the top head 211. The valve stem can be operated from outside the valve body through the operating mechanism to realize axial movement of the valve stem in the first circular hole.

[0048] See Figure 3 and Figure 4 and combined Figure 1 , Figure 5 As can be seen, the valve stem 201 includes a guide shaft section 212, and the first circular hole 300 includes a guide hole section 302 located between the end hole section and the bottom hole section. The guide shaft section is adapted to cooperate with the guide hole section to guide the axial movement of the valve stem in the first circular hole. According to an embodiment of the present invention, the guide hole section 302 of the first circular hole 300 is constructed as a threaded hole section with internal threads, and the guide shaft section 212 of the valve stem 201 has external threads that match the internal threads, thereby enabling the axial movement of the valve stem in the first circular hole by screwing the valve stem 201 in or out.

[0049] Based on the implementation where the valve stem and the first circular hole are threaded together, the aforementioned operating mechanism 214 may include a screwdriver or wrench engagement structure located at the corresponding end of the valve stem. For example, it may have a slotted or Phillips head slot corresponding to a screwdriver, or an internal or external hexagonal head slot corresponding to a socket wrench. Of course, in addition to manual operation, the valve stem can also be operated using electromagnetic, electric, or pneumatic drive methods to achieve automatic and precise control of the valve stem's axial movement.

[0050] See Figure 3 and Figure 4 and combined Figure 1 , Figure 5The valve stem 201 includes a sealing shaft section. A sealing mechanism is provided between the outer periphery of the sealing shaft section and the inner wall of the end hole section 303 of the first circular hole 300 to seal the opening of the first circular hole located on the first end face of the valve body, preventing media leakage. Preferably, the sealing mechanism includes a groove 213 formed on the outer periphery of the sealing shaft section and a sealing ring 202 embedded in the groove. Preferably, the sealing ring 202 is an elastic sealing ring made of fluororubber or tetrafluoroethylene (PTFE), and its cross-section is preferably circular. When the three-valve manifold of the present invention is used in conjunction with a differential pressure transmitter, especially for the low-pressure measurement channel, the radial sealing force generated by the elastic fit between the O-ring and the outer periphery of the sealing shaft section and the inner wall of the end hole section 303 of the first circular hole 300 is sufficient. Thus, a low-cost and simple reliable radial seal can be achieved on the low-pressure side.

[0051] like Figure 2 As shown, the first circular hole 300, the central hole 107, and the second circular hole 103 form a through hole that extends from the first end face to the second end face of the valve body. Therefore, because the main channel inside the valve body adopts a straight-through structure design, it can be manufactured using a simple process.

[0052] According to one embodiment of the present invention, the second circular hole 103 includes an end hole section opening into the second end face of the valve body, in which a plug 401 is detachably installed, such as... Figure 1 and Figure 5 As shown.

[0053] The plug 401 can seal the opening of the second circular hole 103 located on the second end face of the valve body. When the three-valve manifold of the present invention is used in conjunction with a differential pressure transmitter, this opening can, for example, be used as a pressure relief port for a high-pressure measurement channel.

[0054] The end section of the second circular hole 103 can be constructed as a threaded section with internal threads, and the plug 401 is constructed as a screw plug with external threads that match the internal threads. Preferably, a sealing gasket, particularly an elastic sealing gasket, is provided between the head of the screw plug and the second end face of the valve body. Accordingly, when the three-valve manifold of the present invention is used in conjunction with a differential pressure transmitter, especially for high-pressure measurement channels, a low-cost and simple, reliable end-face seal can be achieved. At the same time, the magnitude of the axial sealing force can also be adjusted based on the screw tightening force.

[0055] According to one embodiment of the present invention, the second circular hole 103 includes a bottom hole section connected to the central hole 107, and the second measuring medium interface 101 and the second transmitter interface 104 are connected to the bottom hole section. Preferably, the bottom hole section of the second circular hole 103 can be constructed as a cylindrical hole section. Of course, since the bottom hole section of the second circular hole is mainly used to realize the communication function, its construction as a threaded hole section is also acceptable.

[0056] According to one embodiment of the present invention, the first transmitter interface 105 and the second transmitter interface 104 are disposed on the side of the valve body opposite to the first measuring medium interface 102 and the second measuring medium interface 101, such as... Figure 2 As shown. Accordingly, based on the interface layout scheme proposed in this invention, combined with the main channel straight-through structure design described above, all the channels of the valve body can extend in only two directions (one is the longitudinal extension direction of the main channel from the first end face of the valve body to the second end face, and the other is the lateral extension direction of the interface channel from the side of the valve body into the interior), thereby enabling the valve body to be manufactured using simple processes and equipment, and significantly reducing the cost of the three-valve assembly.

[0057] It is worth noting that the above-described arrangement / positional relationship between the transmitter interface and the measuring medium interface in the three-valve manifold is preferred, but not mandatory. Within the framework of this invention, depending on design requirements, structural type, and installation conditions, the first transmitter interface 105 and the second transmitter interface 104 can also be located on other sides of the valve body, as long as it is ensured that the first measuring medium interface 102 and the first transmitter interface 105 are interconnected via the first chamber, and the second measuring medium interface 101 and the second transmitter interface 104 are interconnected via the second chamber.

[0058] The present invention also provides a differential pressure transmitter, particularly a micro differential pressure transmitter, which is equipped with the aforementioned three-valve manifold. As described above, the three-valve manifold of the present invention has the advantages of simple structure, compact design, miniaturization, and convenient maintenance, and is particularly suitable for micro differential pressure transmitters.

[0059] Preferably, the first measuring medium interface 102 is used to introduce a low-pressure measuring medium, and the second measuring medium interface 101 is used to introduce a high-pressure measuring medium. The first measuring medium interface 102, the first chamber, and the first transmitter interface 105 form the low-pressure measuring channel of the differential pressure transmitter, while the second measuring medium interface 101, the second chamber, and the second transmitter interface 104 form the high-pressure measuring channel of the differential pressure transmitter. Accordingly, the three-valve manifold design proposed in this invention allows for reasonable configuration and optimization of the sealing mechanism based on the difference between high and low pressure when used with a differential pressure transmitter. As mentioned above, for the high-pressure measuring channel, an adjustable end-face seal suitable for high pressure can be formed between the plug (screw plug) and the valve body end face; while for the low-pressure measuring channel, a radial seal suitable for low pressure can be formed between the outer periphery of the shaft section and the inner wall of the bore section. Therefore, compared with the prior art, the differential pressure transmitter and its three-valve manifold of this invention also have the following advantages: simple sealing structure, fewer sealing components, and reliable performance, reducing maintenance costs while lowering leakage risk.

[0060] According to the present invention, it is feasible to install a first shut-off valve at the first measuring medium interface or in the pressure-sensing pipeline connected thereto, and to install a second shut-off valve at the second measuring medium interface or in the pressure-sensing pipeline connected thereto. The shut-off valves are used to introduce or shut off the measuring medium. Within the framework of the present invention, the shut-off valves can be flexibly designed and arranged according to the equipment configuration, technical requirements, and installation conditions. Their specific location and form are not limited; for example, they can be plug valves (such as ball plug valves or cylindrical plug valves), plunger valves, butterfly valves, etc.

[0061] Typically, a differential pressure transmitter's three-valve manifold includes a high-pressure valve, a low-pressure valve, and a balancing valve. Here, the operation of the valve stem enables the function of the so-called balancing valve; the first shut-off valve is the low-pressure valve, and the second shut-off valve is the high-pressure valve. The differential pressure transmitter and its three-valve manifold of this invention operate as follows: At startup, the balancing valve is opened (by operating the valve stem, connecting the high and low pressure measurement channels), then the high and low pressure valves are opened (introducing the high and low pressure measurement media), and then the balancing valve is closed (by operating the valve stem, cutting off the high and low pressure measurement channels), allowing measurement operations to be performed. At shutdown: the balancing valve is first opened (by operating the valve stem, connecting the high and low pressure measurement channels), and then the high and low pressure valves are closed (no longer connecting the high and low pressure measurement media), thus stopping the measurement operation.

[0062] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A three-valve manifold for a differential pressure transmitter, suitable for miniaturized micro differential pressure measurement applications, comprising: The valve body (100) has a first chamber and a second chamber formed inside the valve body. The valve body is provided with a first measuring medium interface and a first transmitter interface leading to the first chamber, and a second measuring medium interface and a second transmitter interface leading to the second chamber. The first chamber is constructed as a first circular hole (300), and the second chamber is constructed as a second circular hole (103). A valve stem assembly (200) includes a valve stem (201) extending into the valve body, the valve stem being movable longitudinally therein to connect or disconnect the first chamber from the second chamber; The first measuring medium interface and the second measuring medium interface are located on the same side of the valve body and are arranged laterally relative to the longitudinal axis of the valve stem. The valve stem (201) includes a sealing shaft section, and a sealing mechanism is provided between the outer periphery of the sealing shaft section and the inner wall of the end hole section (303) of the first circular hole (300); The first chamber is a low-pressure measurement channel, and the second chamber is a high-pressure measurement channel. The sealing mechanism includes a groove (213) formed on the outer periphery of the sealing shaft section and a sealing ring (202) embedded in the groove. The second circular hole (103) includes an end hole section that opens to the second end face of the valve body. A plug (401) is detachably installed in the end hole section. The plug (401) can seal the opening of the second circular hole (103) on the second end face of the valve body. The top of the valve stem (211) is conical. The bottom surface of the bottom hole section (301) of the first chamber is a plane. The conical top cooperates with the plane to achieve a seal.

2. The three-valve assembly according to claim 1, characterized in that, The first circular hole and the second circular hole are interconnected through a central hole (107), and at least the first circular hole (300) is coaxial with the central hole.

3. The three-valve assembly according to claim 2, characterized in that, The first circular hole (300) includes an end hole section (303) opening to the first end face of the valve body and a bottom hole section (301) connected to the center hole (107). The valve stem (201) extends into the valve body from the first end face of the valve body and can move axially in the first circular hole (300) to close or release the opening of the center hole (107) located on the bottom surface of the bottom hole section (301).

4. The three-valve assembly according to claim 3, characterized in that, The first measuring medium interface and the first transmitter interface are connected to the bottom hole section (301) of the first circular hole (300) at least when the opening of the central hole (107) is released.

5. The three-valve assembly according to claim 3, characterized in that, The valve stem (201) includes a head (211) that engages with the opening of the central hole (107) to close or release the opening.

6. The three-valve assembly according to claim 5, characterized in that, The valve stem (201) is equipped with an operating mechanism at one end opposite to the top head (211), through which the valve stem can be operated from outside the valve body.

7. The three-valve assembly according to claim 3, characterized in that, The valve stem (201) includes a guide shaft section (212), and the first circular hole (300) includes a guide hole section (302) between the end hole section and the bottom hole section. The guide shaft section is adapted to cooperate with the guide hole section to guide the axial movement of the valve stem in the first circular hole.

8. The three-valve assembly according to claim 7, characterized in that, The guide hole section (302) of the first circular hole (300) is constructed as a threaded hole section with internal threads, and the guide shaft section (212) of the valve stem (201) has an external thread that matches the internal thread, thereby enabling the valve stem to move axially in the first circular hole by screwing in or out of the valve stem (201).

9. The three-valve assembly according to any one of claims 2 to 8, characterized in that, The first circular hole (300), the center hole (107), and the second circular hole (103) form a through hole that extends from the first end face to the second end face of the valve body.

10. The three-valve assembly according to claim 1, characterized in that, The end hole section of the second circular hole (103) is constructed as a threaded hole section with internal threads, and the plug (401) is constructed as a screw plug with external threads that match the internal threads.

11. The three-valve assembly according to claim 2, characterized in that, The second circular hole (103) includes a bottom hole section connected to the central hole (107), and the second measuring medium interface and the second transmitter interface are connected to the bottom hole section.

12. The three-valve assembly according to claim 1, characterized in that, The first transmitter interface and the second transmitter interface are located on the side of the valve body opposite to the first measuring medium interface and the second measuring medium interface.

13. A differential pressure transmitter, characterized in that, The differential pressure transmitter is equipped with a three-valve manifold as described in any one of claims 1 to 12.

14. The differential pressure transmitter according to claim 13, characterized in that, The first measuring medium interface is used to introduce a low-pressure measuring medium, and the second measuring medium interface is used to introduce a high-pressure measuring medium. The first measuring medium interface, the first chamber, and the first transmitter interface form the low-pressure measuring channel of the differential pressure transmitter, while the second measuring medium interface, the second chamber, and the second transmitter interface form the high-pressure measuring channel of the differential pressure transmitter.

15. The differential pressure transmitter according to claim 13 or 14, characterized in that, A first shut-off valve is provided at the first measuring medium interface or in the pressure tapping pipeline connected thereto, and a second shut-off valve is provided at the second measuring medium interface or in the pressure tapping pipeline connected thereto.

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