Remote transmission device of pressure transmitter and pressure transmitter including the remote transmission device

Abstract

The present invention relates to a remote transmission device of a pressure transmitter and a pressure transmitter including the remote transmission device. In one aspect, a remote transmission device (20) of a pressure transmitter (10) is provided, the remote transmission device comprising a measuring diaphragm (21) and a tube assembly (TA), the tube assembly comprising an outer tube (22) and a conduit (24) contained in the outer tube, the conduit being filled with a conducting fluid so as to be suitable for transmitting a physical quantity sensed by the measuring diaphragm (21) to a transmitter body (40) of the pressure transmitter via the conducting fluid. The tube assembly is provided with a foam metal layer (26) located outside the conduit. The remote transmission device of the pressure transmitter of the present application improves the upper and lower limits of the application temperature range (process temperature and ambient temperature). Moreover, the remote transmission device of the present application can improve the application temperature range while maintaining or even reducing the size of existing products (avoiding vibration problems caused by the increase in size), while not affecting the weight of the remote transmission device and saving costs.

Description

Technical Field

[0001] The invention relates to a remote transmission device of a pressure transmitter and a pressure transmitter comprising the remote transmission device. Background Art

[0002] This section provides background information related to the present disclosure which does not necessarily constitute prior art to the present invention.

[0003] The pressure transmitter converts the physical pressure parameters of gas, liquid, etc. sensed by the sensitive element into a standard electrical signal to supply secondary instruments such as indicator alarms, recorders, and regulators for measurement, indication, and process regulation. In this article, pressure transmitter refers to all transmitters that can measure pressure, including ordinary pressure transmitters, differential pressure transmitters, and level transmitters that use differential pressure to obtain liquid level.

[0004] In some cases, remote pressure transmitters are used to avoid direct contact between the measured medium and the transmitter's sensitive element (isolation diaphragm). These situations include: the measured medium or the measuring environment has a corrosive effect on the transmitter's sensitive element, the measured medium or the measuring environment has a high temperature, there are suspended solids or high-viscosity media in the measured medium, the measured medium is easy to solidify or crystallize, and the measuring head needs to be strictly purified when changing the measured medium.

[0005] The working principle of the remote pressure transmitter is roughly as follows: the process (measured) medium contacts the measuring diaphragm of the remote transmission device, the measuring diaphragm senses the pressure of the process medium and transmits the pressure to the main diaphragm (or isolation diaphragm) of the transmitter body through the conduction oil (usually silicone oil), the isolation diaphragm of the transmitter body then transmits the sensed pressure changes to the central diaphragm through the conduction oil, the sensor part extracts the pressure value, and outputs the corresponding pressure value through signal conversion.

[0006] There is room for improvement in the application temperature range of the remote transmission device of the pressure transmitter in the related art. For example, the direct remote transmission device of the differential pressure transmitter increases the application temperature range of the transmitter by extending the length of the outer tube containing the capillary (filled with conductive oil) to avoid evaporation of the conductive oil in the transmitter and damage to the electronic components when the process temperature is too high. The temperature range of the direct remote transmission device can be applied to a process temperature of 370°C (the process temperature is the temperature of the measured medium or the fluid to be measured) and an ambient temperature of 55°C. However, due to the size of the device and the applicable temperature of the conductive oil itself, the extended application temperature range of the device is limited. At the same time, the extended outer tube also causes increased vibration, resulting in damage to components and affecting the measurement accuracy.

[0007] In addition, other remote transmission devices in the related art (e.g., wide temperature devices) increase the application temperature range by providing a variety of different conduction fluids (conducting oils) or combinations thereof, for example, when using silicone oil 704, it can be applied to a process temperature of 315°C and an ambient temperature of -80°C; when using silicone oil 705, it can be applied to a process temperature of 370°C and an ambient temperature of -65°C; when using 805 oil, it can be applied to a process temperature of 410°C and an ambient temperature of -50°C. However, the structure of the remote transmission device is complex and the cost is expensive. Summary of the invention

[0008] An object of one or more embodiments of the present invention is to provide a remote transmission device for a pressure transmitter to solve or alleviate one or more of the above problems.

[0009] The present invention provides a remote transmission device for a pressure transmitter, the remote transmission device comprises a measuring diaphragm and a tube assembly, the tube assembly comprises an outer tube and a conduit accommodated in the outer tube, the conduit is filled with a conducting fluid so as to be suitable for transmitting a physical quantity sensed by the measuring diaphragm to a transmitter body of the pressure transmitter via the conducting fluid, and the tube assembly is provided with a foam metal layer located on the outside of the conduit.

[0010] Preferably, the foam metal layer is disposed in the space between the conduit and the inner wall of the outer tube as an inner metal layer, and / or the foam metal layer is disposed on the outer wall of the outer tube as an outer metal layer.

[0011] Preferably, the inner metal layer contacts the conduit.

[0012] Preferably, the inner metal layer completely surrounds the conduit in the circumferential direction and / or completely surrounds the conduit in the axial direction, or partially surrounds the conduit but is arranged on an end portion of the conduit close to the measuring diaphragm.

[0013] Preferably, the inner metal layer fills up the space between the conduit and the inner wall of the outer tube in the radial direction.

[0014] Preferably, the outer tube is an integrally formed single component with the inner metal layer and / or the outer metal layer.

[0015] Preferably, the outer metal layer is an open-cell foam metal layer, and the inner metal layer is a closed-cell foam metal layer.

[0016] Preferably, the foam metal layer is an aluminum foam metal layer configured to have a thermal conductivity of 31-49 W / (m*K).

[0017] Preferably, the remote transmission device also includes: a first connecting portion arranged at one end of the tube assembly, the tube assembly being connected to the transmitter body via the first connecting portion; and a second connecting portion arranged at the other end of the tube assembly, the tube assembly being connected to a remote sealing measuring portion provided with the measuring diaphragm via the second connecting portion.

[0018] Preferably, the second connecting portion is provided with an oil filling hole for filling the conduit with a conducting fluid.

[0019] The present invention also provides a pressure transmitter, which includes the above-mentioned remote transmission device.

[0020] Preferably, the pressure transmitter is a remote direct-connection transmitter.

[0021] Preferably, the transmitter body includes a body diaphragm and a center diaphragm, the body diaphragm senses a physical quantity transmitted by the conduit, and the body diaphragm transmits the sensed physical quantity to the center diaphragm via a body fluid disposed on a side of the body diaphragm opposite to the conduit.

[0022] The present application provides a foam metal layer on the outside of the conduit of the remote transmission device of the transmitter and improves the upper and lower limits of the application temperature (process temperature and ambient temperature) range through the good thermal conductivity of the foam metal. In addition, the remote transmission device of the present application can improve the application temperature range while maintaining or even reducing the size of the existing product (avoiding vibration problems caused by the increase in size), while not affecting the weight of the remote transmission device and saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The features and advantages of the present invention will be more easily understood through the following detailed description provided with reference to the accompanying drawings, in which:

[0024] Figure 1 A cross-sectional view of a pressure transmitter using a remote transmission device according to one aspect of an embodiment of the present invention is shown, wherein a foam metal layer is provided between the inner wall of an outer tube of a tube assembly and a conduit.

[0025] Figure 2 A cross-sectional view of a pressure transmitter using a remote transmission device according to another aspect of an embodiment of the present invention is shown, wherein a foam metal layer is provided on an outer wall of an outer tube of a tube assembly. DETAILED DESCRIPTION

[0026] The following description of the preferred embodiment is merely exemplary and is in no way intended to limit the invention, its application, or uses.

[0027] Combination Figure 1 and Figure 2A pressure transmitter using a remote transmission device according to an embodiment of the present invention is described.

[0028] In an embodiment, the pressure transmitter is a remote direct-connection transmitter (hereinafter referred to as "transmitter"), in particular, the transmitter can be a 4-inch remote direct-connection differential pressure transmitter. In the accompanying drawings, the transmitter 10 includes a transmitter body 40 and a remote transmission device 20. The transmitter body 40 includes a body diaphragm (isolation diaphragm) 42 and a center diaphragm. The remote transmission device 20 includes: a remote sealed measuring part 27 provided with a measuring diaphragm 21; a pipe assembly TA, the pipe assembly includes an outer pipe 22 and a conduit (preferably, the conduit can be a capillary tube) 24 accommodated in the outer pipe 22; a first connecting part 28 provided at one end of the pipe assembly TA, the pipe assembly TA is connected to the transmitter body 40 via the first connecting part 28; and a second connecting part 29 provided at the other end of the pipe assembly TA, the pipe assembly TA is connected to the remote sealed measuring part 27 via the second connecting part 29. The second connecting part 29 is provided with an oil filling hole 29a for filling the conduit 24 with a conducting fluid. The conduit 24 is filled with a conducting fluid, typically an incompressible conducting oil, which may be silicone oil, and is connected to the measuring diaphragm 21 .

[0029] When the transmitter is in operation, the measuring diaphragm 21 is placed in the working environment to be measured, for example, the measuring diaphragm 21 is in contact with the fluid to be measured (process medium), and the conduit 24 transmits the physical quantity (for example, pressure or pressure change) sensed by the measuring diaphragm 21 to the body diaphragm 42 of the transmitter body 40 via the conducting fluid, and the body diaphragm 42 senses the physical quantity transmitted by the conducting fluid in the conduit 24, and the body diaphragm 42 transmits the sensed physical quantity to the central diaphragm (not shown) via the body fluid (the body fluid can be the same conducting oil as the conducting oil in the conduit 24 or a different conducting oil) disposed on the side of the body diaphragm 42 opposite to the conduit 24. The central diaphragm can be an electronic device or a mechanical device such as a pressure-sensitive element disposed in the transmitter body, so that the obtained physical quantity can be converted into a digital quantity required in the actual production process, such as a pressure value displayed on the instrument panel.

[0030] In other embodiments, the transmitter described in the present application may also be used as other types of remote measurement devices, such as a liquid level meter, a flow meter, and the like.

[0031] In the remote transmission device 20 according to the present invention, the pipe assembly TA is provided with a foam metal layer 26 located on the outside of the conduit 24, so that the upper and lower limits of the application temperature range (process temperature and ambient temperature) can be increased by the good thermal conductivity of the foam metal. The remote transmission device of the present application can increase the application temperature range while maintaining or even reducing the size of existing products (reducing vibration problems caused by the increase in size), while not affecting the weight of the device and saving costs. In the art, other methods are generally used to expand the application temperature range of the remote transmission device due to factors such as the strength of the foam metal. However, the inventors of the present application have found that by selecting a suitable foam metal layer and / or combining it with specific components of the remote transmission device, very good results can be obtained.

[0032] Preferably, the foam metal layer 26 may be an aluminum foam metal layer configured to have a thermal conductivity of 31-49 W / (m*K), more preferably, the aluminum foam metal layer may have a thermal conductivity of 35-45 W / (m*K), and even more preferably, may have a thermal conductivity of 37-43 W / (m*K). By selecting a suitable foam metal layer configured to have a desired thermal conductivity, it is possible to adequately control the excessive transfer of heat from the high-temperature measured medium to the body fluid in the transmitter body while fully transferring heat to the external environment.

[0033] like Figure 1 As shown, the foam metal layer 26 can be arranged in the space between the conduit 24 and the inner wall of the outer tube 22 as the inner metal layer 26a. The inner foam metal layer can facilitate the heat conduction of the conduit so as to prevent the conductive fluid (conductive oil) in the transmitter (especially the transmitter body at the proximal end) from freezing due to too low an ambient temperature, thus helping to expand the lower limit of the use of the transmitter with respect to the ambient temperature. Preferably, the inner metal layer 26a can contact the conduit 24, in this way, allowing more heat to be transferred from the measured medium to, for example, the conductive oil in the transmitter body under certain circumstances (for example, when the weather is cold).

[0034] In the illustrated embodiment, the inner metal layer 26a advantageously completely surrounds the conduit 24 in the circumferential direction, and the inner metal layer 26a partially surrounds the conduit 24 in the axial direction, in particular, is arranged on the end portion of the conduit 24 close to the measuring diaphragm 21, so that in the event of excessively high process temperatures, a gradual thermal conductivity gradient is provided to avoid overheating of, for example, the oil in the transmitter body.

[0035] However, in other embodiments, depending on the specific application, i.e., the specific conditions of the process temperature and the ambient temperature, the inner metal layer 26a may partially surround the conduit 24 in the circumferential direction, or completely surround the conduit 24 in the axial direction. In addition, in the illustrated example, the inner metal layer 26a may fill the space between the conduit 24 and the inner wall of the outer tube 22 in the radial direction, i.e., the inner metal layer 26a contacts both the inner walls of the conduit 24 and the outer tube 22.

[0036] like Figure 2 As shown, additionally or alternatively, a foam metal layer 26 can be provided on the outer wall of the outer tube 22 as an outer metal layer 26b. Since the outer foam metal layer is conducive to heat dissipation to prevent the conductive fluid in the transmitter from evaporating due to excessively high process temperature, it helps to expand the upper limit of the use of the transmitter with respect to the process temperature.

[0037] It should be pointed out that, based on the description herein, a person skilled in the art can understand that the foam metal layer can be constructed as an inner foam metal layer and an outer foam metal layer at the same time as needed, in this way, the inner foam metal layer and the outer foam metal layer can each play their special functions, thereby further expanding the application temperature range as a whole. Moreover, in the above-mentioned embodiment, the outer tube 22 and the inner metal layer 26a and / or the outer metal layer 26b are a single component formed integrally, in this way, a remote transmission device can be made in a simple manner. In addition, the above-mentioned outer metal layer 26b can be an open-cell foam metal layer to be more conducive to heat dissipation, and / or the above-mentioned inner metal layer 26a can be a closed-cell foam metal layer to be more conducive to heat conduction.

[0038] Although various embodiments of the present invention have been described in detail herein, it should be understood that the present invention is not limited to the specific embodiments described and shown in detail herein, and other variations and modifications may be implemented by those skilled in the art without departing from the essential spirit and scope of the present invention. All such variations and modifications fall within the scope of the present invention.

Claims

1. A remote transmission device (20) of a pressure transmitter (10), the remote transmission device comprising a measuring diaphragm (21) and a tube assembly (TA), the tube assembly comprising an outer tube (22) and a conduit (24) accommodated in the outer tube (22), the conduit (24) being filled with a conducting fluid so as to be suitable for transmitting a physical quantity sensed by the measuring diaphragm (21) to a transmitter body (40) of the pressure transmitter (10) via the conducting fluid, characterized in that: The tube assembly (TA) is provided with a foamed metal layer (26) located outside the conduit (24).

2. The remote transmission device (20) according to claim 1, wherein: The foam metal layer (26) is arranged in the space between the conduit (24) and the inner wall of the outer tube (22) as an inner metal layer (26a), and / or the foam metal layer (26) is arranged on the outer wall of the outer tube (22) as an outer metal layer (26b).

3. The remote transmission device (20) according to claim 2, wherein: The inner metal layer (26a) contacts the conduit (24).

4. The remote transmission device (20) according to claim 2, wherein: The inner metal layer (26a) completely surrounds the conduit (24) in the circumferential direction, and / or, The inner metal layer (26a) completely surrounds the conduit (24) in the axial direction, or partially surrounds the conduit (24) but is arranged on the end portion of the conduit (24) close to the measuring diaphragm (21).

5. The remote transmission device (20) according to claim 2, wherein: The inner metal layer (26a) fills the space between the conduit (24) and the inner wall of the outer tube (22) in the radial direction.

6. The remote transmission device (20) according to any one of claims 2 to 5, wherein: The outer metal layer (26b) is an open-cell foam metal layer, and the inner metal layer (26a) is a closed-cell foam metal layer.

7. The teletransmission device (20) according to one of claims 1 to 5, wherein: The remote transmission device further comprises: a first connection portion (28) arranged at one end of the tube assembly (TA), the tube assembly (TA) being connected to the transmitter body (40) via the first connection portion (28); and a second connection portion (29) arranged at the other end of the tube assembly (TA), the tube assembly (TA) being connected to a remote sealing measurement portion (27) provided with the measuring diaphragm (21) via the second connection portion (29).

8. The remote transmission device (20) according to claim 7, wherein: The second connecting portion (29) is provided with an oil filling hole (29a) for filling the conduit (24) with a conducting fluid.

9. A pressure transmitter (10), characterized in that: The pressure transmitter comprises a remote transmission device (20) according to any one of claims 1 to 8.

10. The pressure transmitter (10) according to claim 9, wherein: The pressure transmitter (10) is a remote direct-connection transmitter.

11. The pressure transmitter (10) according to claim 9 or 10, wherein: The transmitter body (40) includes a body diaphragm (42) and a center diaphragm, wherein the body diaphragm (42) senses a physical quantity transmitted by the conduit (24), and the body diaphragm (42) transmits the sensed physical quantity to the center diaphragm via a body fluid disposed on a side of the body diaphragm (42) opposite to the conduit (24).

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