瑞士专利CH716407A2 GWR probe for interface measurement for viscous fluids.

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专利摘要:
The invention relates to a probe used with a level measuring instrument that includes a pulse circuit for generating pulses. A coaxial connector is attached to the probe housing (60) so that the probe housing (60) is electrically connected to the ground shield. A center post (66) has an upper end that is received in the probe housing and extends into a process fluid. The center rod is electrically connected to the center connector for conducting the pulses. The ground rods (68, 69, 70, 71) are distributed around the center rod (66) and attached to the probe housing (60). The probe provides an open configuration that is less prone to debris between the center rod and the ground rods. One or more of the ground rods can be provided with nozzles for cleaning the center rod through pipes connected to a flushing interface. Another ground rod can be tubular to carry a conductor that is connected to the bottom of the center rod for bottom-up measurement.
公开号:CH716407A2
申请号:CH00772/20
申请日:2020-06-26
公开日:2021-01-15
发明作者:G Janitch Paul
申请人:Magnetrol Int Incorporated；
IPC主号:

专利说明:

description
CROSS REFERENCE TO RELATED APPLICATIONS
There are no related applications.
FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT
[0002] Not applicable.
MICROFICHE / COPYRIGHT REFERENCE
[0003] Not applicable.
FIELD OF THE INVENTION
This invention relates to process control instruments and, more particularly, to a waveguide radar probe for use in interface measurement applications and for viscous fluids.
BACKGROUND
Process control systems require the precise measurement of process variables. Typically a primary element detects the value of a process variable and a transmitter develops an output, the value of which varies depending on the process variable. For example, a level transmitter includes a primary element for sensing the level and circuitry for developing an electrical signal proportional to the sensed level.
Knowledge of the fill level in industrial process tanks or containers has long been required for the safe and cost-effective operation of systems. There are many technologies for making level measurements. These include buoyancy, capacitance measurement, ultrasonic and microwave radar, to name a few. Recent advances in micropower impulse radar (MIR), also known as ultra-wideband radar (UWB), combined with advances in equivalent time sampling (ETS), enable the development of time domain reflectometry (TDR) instruments with low performance and low cost.
In a TDR instrument, a very fast pulse with a rise time of 500 picoseconds or less is transmitted through a probe that acts as a transmission line in a container. The pulse is reflected by a discontinuity caused by a transition between two media. In level measurements, this transition is typically where the air and the material to be measured meet. These instruments are also known as waveguide radar (GWR) gauges.
One type of probe used by GWR level gauges is a coaxial probe. The coaxial probe consists of an outer tube and an inner conductor. When a coaxial probe is immersed in the fluid to be measured, there is a section of constant impedance, generally air, above the fluid surface. An impedance discontinuity arises on the flat surface due to the change in the dielectric constant of the fluid with respect to air at that point. When the GWR signal encounters an impedance discontinuity in the transmission line, part of the signal is reflected back to the source in accordance with theory based on Maxwell's Laws. The GWR instrument measures the travel time of the electrical signal to this reflective point, which is the fluid surface, and back to find the fluid level.
GWR probes are often used in tanks where there may be multiple layers of fluid or in applications with high viscosity fluids. An example of such an application is in the oil and gas industry. Well fluid containing crude oil, water, sand, and other contaminants is mixed into a separator tank. This is shown in FIG. 1 generally illustrates. The fluids are layered over the density variations of gases above, oil in the middle and water below. The solids sink to the bottom of the tank or are suspended from a separator between adjacent layers. An emulsion layer consisting of a mixture of water and oil forms between the layers while the layer formation process stabilizes. After a period of time, the components can be separated by weirs or other means.
The goal of the GWR probe in such applications is to accurately measure multiple levels including the top of the oil layer, the bottom of the oil layer (i.e. the top of the emulsion layer), and the top of the water layer (i.e. the bottom of the emulsion layer). There are several difficulties with using GWR measuring instruments in interface applications or with viscous fluids. GWR is often used to measure fluid interface levels where the dissimilar dielectric properties of adjacent layers create a reflection of the transmitted signal at the interface. However, interface detection becomes more difficult when there is a thick layer of emulsion and the dielectric properties of the fluid gradually change. It has been observed that a small percentage of water in the oil creates a significant difference in dielectric properties when compared to oil alone. A small percentage of the oil in the water behaves similarly to water alone. It is therefore more difficult to recognize the separating layer between water and an emulsion of water with a small proportion of oil than the separating layer between oil and an emulsion of oil with a
low proportion of water. Therefore, it is more difficult to see the bottom of the emulsion layer than the top of the emulsion layer.
In addition, some components of the crude oil can be highly viscous or sticky and cause deposits in a coaxial GWR probe. Excessive deposits in the probe can lead to measurement errors or completely prevent the probe from operating. In addition, the transmitted energy is absorbed in the oil and emulsion layers. This makes it difficult to identify the underside of the emulsion.
The present invention is directed to solving one or more of the problems discussed above in a novel and simple manner.
SHORT REPRESENTATION
As described herein, a probe is adapted for use in interface measurement and for use with viscous fluids.
In accordance with one aspect, a probe defines a transmission line for use with a measurement instrument that includes pulse circuitry coupled to the probe for generating pulses on the transmission line and for receiving reflected pulses on the transmission line. The probe includes a process connection for mounting on a process vessel. A cylindrical probe housing extends over the process connection. A coaxial connector has a center connector and a ground shield for connection to the pulse circuit. The coaxial connector is attached to the probe housing so that the probe housing is electrically connected to the ground shield. An elongated central rod has an upper end that is received coaxially in the probe housing and extends downwardly from the process connection into a process fluid. The central rod is electrically connected to the central terminal for conducting the pulses. At least three elongated ground rods are equiangularly spaced around the center rod and attached to the probe housing so that they extend into the process fluid. The probe provides an open configuration that is less susceptible to debris between the center rod and the ground rods.
It is a feature that the central rod comprises a metal rod with a fluorocarbon outer sleeve.
Another feature is that the ground rods comprise metal tubes. The probe housing can include a flushing interface that communicates with one or more channels in the probe housing, and one or more of the ground rods open into one or more of the channels. The one or more of the ground rods include a plurality of spray nozzles aimed at the center rod.
Another feature is that one of the ground rods comprises a tube and also an electrical cable with a coaxial connector in the probe housing at an upper end for connection to the probe circuit and the cable runs through the tube and with a lower end of the central rod for measurement connected from bottom to top.
It is another feature that a cylindrical, lower housing receives the underside of the center rod. A pin assembly has a pin connected to the center post and a socket received in the lower housing for connection to a coaxial connector at the lower end of the cable.
Another feature is the provision of four elongated ground rods equiangularly spaced around the center rod and attached to the probe housing so that they extend into the process fluid.
In accordance with a further aspect, a probe is described which comprises a process connection for mounting on a process vessel. A cylindrical probe housing extends over the process connection. A connector is attached to the probe housing for connection to the pulse circuit. An elongated central rod has an upper end that is received coaxially in the probe housing and extends downwardly from the process connection into a process fluid. The central rod is electrically connected to the connector for conducting the impulses. A plurality of elongated, tubular ground rods are equiangularly spaced around the center rod and attached to the probe housing so that they extend into the process fluid. The probe housing includes a flushing interface that communicates with one or more channels in the probe housing, and one or more of the tubular grounding rods open into one or more channels. The one or more of the tubular ground rods include a plurality of spray nozzles aimed at the center rod.
It is a feature that the probe housing has a through opening which widens at the upper end of the housing to define a shoulder and an annular channel surrounds the through opening above the shoulder. The flushing interface is located in one side of the housing and opens into the annular channel, and the one or more vertical channels in the probe housing are in connection with the annular channel. The one or more tubular ground rods are aligned with the one or more vertical channels.
Another feature is that a gland grommet is received in the upper end of the probe housing and rests on the shoulder to receive the center rod in the probe housing.
In accordance with a further aspect, a probe with a process connection for mounting on a process vessel is disclosed. A cylindrical probe housing extends over the process connection. For the
A connector is attached to the probe housing for connection to the pulse circuit. An elongated central rod has an upper end that is received coaxially in the probe housing and extends downwardly from the process connection into a process fluid. The central rod is electrically connected to the connector for conducting the impulses. A plurality of elongated ground rods are spaced around the center rod and attached to the probe housing so that they extend into the process fluid. One of the ground rods is tubular and receives an electrical cable with a coaxial connector in the probe housing at an upper end for connection to the probe circuit, and the cable passes through the tubular ground rod and is connected to a lower end of the center rod for bottom-up measurement.
Further features and advantages will emerge from a review of the entire patent specification, including the appended claims and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a process vessel with a waveguide radar (GWR) measuring instrument with a probe for level measurement in tanks with multiple fluid layers and / or highly viscous fluids;
FIG. 2 is a generalized view of the FIG. 1 GWR measuring instrument used;
FIG. 3 is a side view of the GWR probe;
FIG. 4 is a cutaway perspective view of the top of the GWR probe;
FIG. 5 is a sectional view taken along line 5-5 of FIG. 6;
FIG. 6 is a sectional view of the side view of the GWR probe;
FIG. 7 is a side view similar to FIG. 6, shown in section;
FIG. 8 is a perspective view of a probe top assembly.
FIG. 9 is a bottom perspective view of a molded circuit module;
FIG. 10 is a side view of the probe top showing the molded module mounted on the probe top;
FIG. 11 is a sectional view of the probe top of FIG. 10; and
FIG. 12 is a sectional view of the probe bottom.
DETAILED DESCRIPTION
Referring to FIG. 1 initially shows a process instrument 20 in the form of a waveguide radar (GWR) level measuring instrument which is used on a process container 22. The process vessel 22 is an example and in the illustrated embodiment includes a separator tank 24 having an inlet 26 for receiving flowing wellbore fluid. The tank 24 includes a weir 30 that extends upward from a bottom of the tank 24. A water outlet 32 is located on the bottom of the tank 24 on the inlet side of the weir 30. An oil outlet 34 is located on the opposite side of the weir 30. A gas outlet 36 is provided on the top of the tank 24. The process instrument 20 includes a probe 42 that extends into an interior 44 of the tank 24.
The control circuitry of process tool 20 can take many different forms. This application is particularly directed to probe 42, as described below. It should be noted that in FIG. 1 and FIG. Figure 2 shows the portion of probe 42 that extends into tank 24 in dashed lines as detailed in other figures.
As previously described, the wellbore fluid provided at inlet 26 may include crude oil, water, sand, and other contaminants. The fluids are layered in such a way that an oil layer 46 and a water layer 48 are formed, which are separated by an emulsion 50. The water is to the left of the weir 30 in the position shown in FIG. 1 and can be selectively discharged via the water outlet 32. Oil in the oil layer 46, which is at a higher level than the weir 30, can fall to the right of the weir 30 and, as usual, can be selectively removed via the oil outlet 34. The process instrument 20 is particularly suitable for measuring the top of the oil layer 46, the bottom of the oil layer 46, and the top of the water layer 48.
The probe 42 is adapted to the above-mentioned obstacles. A conventional coaxial probe, when used in viscous fluids, tends to trap product deposits. As described herein, the conventional outer tube of a coaxial probe is replaced with ground rods to create an open configuration that is less susceptible to debris between the center rod and ground rods.
The process instrument 20 uses pulse radar in conjunction with real-time sampling (ETS) and ultra-wideband (UWB) transceivers for level measurement using time domain reflectometry (TDR). In particular, the instrument 20 uses a waveguide radar to detect the fill level. While the embodiment described herein
As relates to a waveguide radar level gauge, various aspects of the invention can be used with other types of process instruments for measuring various process parameters.
The probe 42 is capable of sending and receiving signals from both ends when used in conjunction with a signal circuit having two TDRs. A "top-down" circuit sends a signal from the top to the bottom of the probe 42 and detects signals that are reflected back upwards. A "bottom-up" circuit sends a signal from the bottom to the top of the probe 42 and detects signals which are reflected back to the bottom. The ability to transfer from bottom to top has the advantage of improved recognition of the emulsion layer underside. Such a system is described in applicant's co-pending patent application no. 16 / 278,368 on February 18, 2019, the specification of which is incorporated herein by reference. The transmission cable for the "bottom-up" transmission line runs through one of the ground rods, which is tubular as described below.
The probe 42 has a central rod which can be made of stainless steel or other metal. Nickel alloys such as Hastelloy or Inconel can be used for corrosion resistance. The rod has a PFA sleeve. Other fluorocarbon materials such as PTFE or other electrically insulating coatings can be used. The purpose is to allow maximum signal penetration through the process, as described in U.S. Applicant's patent 9,360,361.
As described below, the ground rods can be tubular. In the illustrated embodiment, two of the ground rods have a series of milled bores for creating cleaning nozzles. These tubes are on opposite sides of the center post with the cleaning nozzles facing the center post. Pressurized cleaning fluid enters an irrigation interface in the top of the probe, flows through internal channels in the probe housing and into the irrigation tube grounding rods. The fluid exits the ground rods through nozzles where it sprays and cleans the center rod.
Referring to FIG. 2, the process instrument 20 includes a control housing 52, the probe 42, and a cable 54 for connecting the probe 42 to the housing 52. The probe 42 is mounted on the process vessel 22 using a process connection, such as a flange 56. Alternatively, a process adapter could be used. The housing 52 is removed from the probe 42. The probe 42 includes a radio frequency transmission line that, when placed in a fluid, can be used to measure the fluid level. In particular, the probe 42 is controlled by a controller (not shown) in the housing 52 for determining the fill level in the container. Control can take many known forms. The present invention is not limited to any particular control.
As is known, the controller causes the probe 42 to generate and transmit pulses. A reflected signal is developed from any changes in impedance, such as the fluid surface of the material to be measured. A small amount of energy can continue in the probe 42.
The waveguide radar combines TDR, ETS, and low power circuits. TDR uses pulses of electromagnetic (EM) energy to measure distances or levels. When a pulse reaches a dielectric discontinuity, some of the energy is reflected. The greater the dielectric difference, the greater the amplitude of the reflection. In the measuring instrument 20, the probe 42 comprises a waveguide with a wave resistance in air. If a portion of the probe 42 is immersed in a material other than air, there will be a lower impedance due to the increase in the dielectric. When the EM pulse is sent down the probe and hits the dielectric discontinuity, a reflection is created.
ETS is used to measure EM energy at high speed, low power. The high speed EM (1000 feet / microsecond) energy is difficult to measure over short distances and with the resolution required in the process industry. ETS captures the EM signals in real time (nanoseconds) and reconstructs them in the equivalent time (milliseconds), which is much easier to measure. ETS is performed by scanning the waveguide to collect thousands of samples. Approximately eight samples are taken per second.
The probe 42 uses a pulse circuit 58 shown in FIG. 7 is shown in block diagram form and controlled by the controller in control box 52 for generating pulses on the transmission line and for receiving reflected pulses on the transmission line representing levels of interest.
The general concept implemented by the ETS circuit is known. The pulse circuit 58 generates hundreds of thousands of very fast pulses with a rise time of 500 picoseconds or less per second. The time between pulses is strictly controlled. The reflected pulses are sampled at controlled intervals. The samples form a time-multiplied "image" of the reflected pulses. Since these pulses travel on the probe 42 at the speed of light, this image represents about ten nanoseconds in real time for a 1.5 m probe. The pulse circuit 58 roughly converts the time Seventy-one milliseconds around. As can be seen, the exact point in time would depend on various factors, such as the probe length. The largest signals have an amplitude on the order of twenty millivolts before they are amplified to the desired amplitude with conventional audio amplifiers. The control converts timed interruptions into distance For a given probe length, the controller can calculate the level by taking the probe length and the difference between the
Reference point and the level distance subtracted. Changes in the measured position of the reference target can be used for speed compensation as required or desired.
Referring to FIG. 3-7, the probe 42 comprises a probe housing 60 which, for. Connected to flange 56 by welding. An upper housing 62 is connected to the probe housing 60 and houses the pulse circuit 58 and is closed by a top cover 64. The upper housing 62 includes a threaded side opening 66 for receiving the cable 54, see FIG. 2. A center post 66 is attached to the probe housing 60 which defines the transmission line and is surrounded by four evenly angularly spaced ground posts 68, 69, 70 and 71. The length of the central rod 66 and the ground rods 68-71 depends on the height of the container 22 and the level to be measured. The center rod 66 is a metal rod with a PFA outer sleeve 67. Other materials can be used as discussed above. A lower case 72 is connected to a lower end of the ground rods 68-71 and connected to a lower case 74.
Referring to FIG. 11-11, the probe housing 60 includes a cylindrical stainless steel body 76 with a through opening 78 that is flared at the upper end 80 to define an upwardly directed shoulder 82. An annular channel 84 surrounds the upper end of the through opening 80 at the shoulder 82, see also FIG. 5. An irrigation interface 86 in cylindrical body 76 is radially aligned and in communication with annular channel 84. A pair of vertical channels 88 and 89, see FIG. 7, extend downward from the annular channel 84 and open out on the underside of the cylindrical body 76, as shown in FIG. 7 shown. Cylindrical adapters 90 and 91 are welded to the probe housing body 76 that align with the corresponding vertical channels 88 and 89, and are also welded to the top of the ground rods 68 and 70. In the illustrated embodiment, ground rods 68 and 70 are stainless steel tubes, although other metals can be used. The flushing interface 86 is thus open to the grounding rods 68 and 70 via the annular channel 84 and the vertical channels 88 and 89. The ground rods 68 and 70 include a plurality of vertically spaced nozzle openings 92 shown in FIG. 4 for the ground rod 68 can be seen. The nozzle openings 92 are directed towards the center rod 66.
Referring again to FIG. 11, the second ground rod 69 is a metal pipe, such as stainless steel or the like, which is connected to the cylindrical probe body 76 via an adapter 92. The fourth ground rod 71, which is also a metal pipe such as stainless steel or the like, is suitable for receiving a coaxial cable 94 used for bottom-up measurement. The ground rod 71 is attached as if by welding to a cylindrical connector 96 which is connected to an enlarged cylindrical adapter 96 which is connected to the cylindrical probe body 76 in alignment with a blind bore 98 in communication with a through opening 100. The adapter 96 is used to offset the cable 94 to bypass the sealing structure, as discussed below. A subminiature coaxial connection of version B (SMB) 102, see also FIG. 8, is connected at the top of the probe body 76 at the through opening 100 for connection to the cable 94.
A PTFE gland grommet 104 is received in the probe housing, opens the top 80 and rests on shoulder 82. The gland grommet 104 includes outer O-rings 106 for sealing with the probe housing body 76. The gland grommet 104 includes a downwardly opening blind hole 108 for receiving the center rod 66 and is provided with O-ring seals 110. A stainless steel ferrule 112 screws into the open top end 80 to slide the gland grommet 104 against the shoulder 82. The ring socket 112 receives a pin 114 which is encapsulated in epoxy resin 116. The pin 114 is electrically connected to the center post 66 and at an opposite end to an SMB connector 118, see also FIG. 8th.
As shown in FIG. 12, the lower housing 72 is cylindrical and made of stainless steel and has an upwardly opening blind bore 120 that receives a PTFE gland bushing 122 that receives a lower end of the center rod 66. A through opening 124, which is aligned with the blind bore 120, receives a pin 126, which is surrounded with epoxy resin 128. The pin 126 is connected at one end to the center post 66 and at the opposite end to an SMB connector 130 for connection to a coaxial connector 132 connected to a lower end of the cable 94. The cable 94 runs through a vertical opening 134 in the lower probe housing 72 which receives a cylindrical adapter 136 for connecting the fourth ground rod 71 to the lower probe housing 72. A solid adapter 138, similar to adapter 92 of FIG. 11, is used to secure the second ground rod 69 to the lower housing 72, e.g., by welds. Similar connector plugs (not shown) are used for ground rods 68 and 70. These welds for the ground rods 68-71 connect the lower housing 72 directly to the probe housing 60. As a result, the center rod 66 is captured between the two PTFE gland bushings 104 and 122 at each end and sealed with O-rings.
Referring to FIG. 9, a potted module 140 is shown. The molded module 140 comprises a plastic housing 142 which encloses the circuit boards 144 and 146, see FIG. 11, including that shown in FIG. 7 pulse circuit shown in block form 58. A pair of coaxial connectors 148 and 150 extend downwardly from the lower circuit board 146, with the entire structure covered with a potting compound 152 to seal the circuit. As in FIG. 10, the encapsulated module 140 is mounted on top of the probe housing 60, with the connector 118 connected to connector 148 and connector 102 to connector 150 to make electrical connections between the pulse circuit 58 and the center rod 66 at both the top and bottom to be provided at the lower end.

权利要求:
Claims (20)
[1]
While probe 42 is shown with four ground rods 68-71, the probe could use three ground rods. If you have three ground rods, the probe is called a four-wire probe, while if you have four ground rods, the probe is called a five-wire probe.
Thus, according to the invention, the probe 42 has three or more ground rods in place of the traditional coaxial tube. This open configuration reduces buildup on the probe while providing performance similar to a coaxial probe configuration. The ground rods may be tubes with spray nozzles that are used to rinse off debris with cleaning fluids that are connected via the rinse interface 86. In addition, one of the ground rods can be used to route an electrical cable to the lower end of the center rod 66 for the "bottom-up" measurement used for emulsion detection.
In the illustrated embodiment, there are two TDR circuits on circuit board 144 in potted module 140. One is for the top-down signal and the other is for the bottom-up signal. The waveforms are sent from the TDR board 144 to the controller in control box 52, see FIG. 1 and
[2]
2. The level calculations, outputs and the user interface are located on the controller. The circuits may be incorporated by reference as needed or desired, including those in commonly filed Application 16 / 278,368.
As described, the ground shield of the SMB connector plug 102 and 118 connects to the probe housing 60 and thus to the ground rods 68-71 and the lower housing 72. The center conductor of the SMB connector plug 118 for the top-down circuit is connected to pin 114 which passes through epoxy 116 and then through PTFE gland grommet 104 which provides a seal where it connects to center post 66. The tip of the probe is a coaxial transmission line from the SMB connector 118 to the flange surface 56 where it transitions into a five-wire probe. The similar structure at the bottom transitions from a coax to a five wire structure as shown in FIG. 12 shown.
In the illustrated embodiment, the center post 66 is clamped between the upper gland bushing 104 and the lower gland bushing 122 and sealed with O-rings. The pin arrangements at the top and bottom provide appropriate connections to the pulse circuit 58.
As described herein, the waveguide radar probe is therefore used for measuring levels in tanks in which there may be multiple layers of fluid and in applications with highly viscous fluids.
Those skilled in the art will understand that many changes can be made in the specific forms of the features and components of the disclosed embodiments, while keeping the spirit of the concepts disclosed herein. Accordingly, no limitations on the specific forms of the embodiments disclosed herein should be read into the claims unless specifically mentioned in the claims. Although several embodiments have been described in detail above, other modifications are possible. Other embodiments may be within the scope of the following claims.
Claims
1. A probe defining a transmission line for use with a level gauge that includes pulse circuitry coupled to the probe for generating pulses on the transmission line and for receiving reflected pulses on the transmission line representing levels of interest, the probe comprising:
a process connection for mounting on a process vessel;
a cylindrical probe housing extending over the process connection;
a coaxial connector having a center connector and a ground shield for connection to the pulse circuit, the coaxial connector being attached to the probe housing so that the probe housing is electrically connected to the ground shield;
an elongated center rod having an upper end coaxially received in the probe housing and extending downwardly from the process port to extend into a process fluid, the center rod electrically connected to the center port to conduct the pulses; and
at least three elongated grounding rods are arranged equiangularly around the center rod and attached to the probe housing so that they extend into the process fluid,
wherein the probe provides an open configuration that is less susceptible to debris between the central rod and ground rods.
2. The probe of claim 1, wherein the central rod comprises a metal rod with a fluorocarbon sleeve surrounding the metal rod.
[3]
3. The probe of claim 1, wherein the ground rods comprise metal tubing.
[4]
4. The probe of claim 3, wherein the probe housing includes a flush interface in communication with one or more channels in the probe housing and one or more of the ground rods in the one or more
Open channels, wherein the one or more ground rods comprise a plurality of spray nozzles which are directed at the central rod.
[5]
5. The probe of claim 1, wherein one of the ground rods comprises a tube and further comprises an electrical cable with a coaxial connector in the probe housing at an upper end for connection to the probe circuit and the cable extends through the tube and with a lower end of the central rod for measuring connected from the bottom to the top.
[6]
6. The probe of claim 5 further comprising a cylindrical lower housing that receives the lower end of the central rod and a pin assembly having a pin connected to the central rod and a socket received in the lower housing for connection to a coaxial connector at the lower end of the cable.
[7]
7. The probe of claim 1 comprising four elongated ground rods equiangularly spaced around the center rod and attached to the probe housing so that they extend into the process fluid.
[8]
8. A probe defining a transmission line for use with a level gauge that includes pulse circuitry coupled to the probe for generating pulses on the transmission line and for receiving reflected pulses on the transmission line representing levels of interest, the probe comprising:
a process connection for mounting on a process vessel;
a cylindrical probe housing extending over the process connection;
a connector attached to the probe body for connection to the pulse circuit;
an elongated central rod having an upper end coaxially received in the probe housing and extending downwardly from the process port to extend into a process fluid, the central post electrically connected to the connector to conduct the pulses; and
multiple elongated tubular ground rods are spaced around the center rod and attached to the probe housing so that they extend into the process fluid,
wherein the probe housing comprises a flushing interface in communication with one or more channels in the probe housing and one or more of the tubular grounding rods open into the one or more channels, the one or more tubular grounding rods comprising a plurality of spray nozzles which are directed at the central rod.
[9]
9. The probe of claim 8, wherein the probe housing has a through opening that widens at an upper end of the housing to define a shoulder, and an annular channel surrounds the through opening above the shoulder, and wherein the flushing interface is in one side of the housing is located and opens into the ring channel and one or more vertical channels in the probe housing are in communication with the ring channel and the one or more tubular grounding rods are aligned with the one or more vertical channels.
[10]
10. The probe of claim 9 further comprising a gland grommet received in the upper end of the probe housing and resting on the shoulder to engage the center post in the probe housing.
[11]
11. The probe of claim 8, wherein one of the tubular ground rods receives an electrical cable having a coaxial connector in the probe housing at an upper end for connection to the probe circuit, and the cable passes through the one of the tubular ground rods and to a lower end of the center rod connected to measure from bottom to top.
[12]
12. The probe of claim 11 further comprising a cylindrical lower housing that receives the lower end of the central rod and a pin assembly having a pin connected to the central rod and a socket received in the lower housing for connection to a coaxial connector at the lower end of the cable.
[13]
13. The probe of claim 8, wherein the central rod comprises a metal rod with a fluorocarbon sleeve surrounding the metal rod.
[14]
14. The probe of claim 8 including four elongated tubular ground rods equiangularly spaced around the center rod and attached to the probe housing so that they extend into the process fluid.
[15]
15. A probe defining a transmission line for use with a level gauge that includes pulse circuitry coupled to the probe for generating pulses on the transmission line and for receiving reflected pulses on the transmission line representing levels of interest, the probe comprising:
a process connection for mounting on a process vessel;
a cylindrical probe housing extending over the process connection;
a connector attached to the probe body for connection to the pulse circuit;
an elongated central rod having an upper end coaxially received in the probe housing and extending downwardly from the process port to extend into a process fluid, the central post electrically connected to the connector to conduct the pulses; and
multiple elongated ground rods are spaced around the center rod and attached to the probe housing so that they extend into the process fluid,
wherein one of the ground rods is tubular and receives an electrical cable with a coaxial connector in the probe housing at an upper end for connection to the probe circuit and the cable passes through the tubular ground rod and is connected to a lower end of the central rod for measurement from bottom to top.
[16]
16. The probe of claim 15 further comprising a cylindrical lower housing that receives the lower end of the central rod and a pin assembly having a pin connected to the central rod and a socket received in the lower housing for connection to a coaxial connector at the lower end of the cable.
[17]
17. The probe of claim 15, wherein the central rod comprises a metal rod with a fluorocarbon sleeve surrounding the central rod.
[18]
18. The probe of claim 15, wherein the ground rods comprise metal tubing.
[19]
19. The probe of claim 18, wherein the probe housing comprises a flushing interface in connection with one or more channels in the probe housing and one or more of the tubular grounding rods open into the one or more channels, the one or more tubular grounding rods comprising a plurality of spray nozzles, which are aimed at the central rod.
[20]
20. The probe of claim 15 including four elongated ground rods equiangularly spaced around the center rod and attached to the probe housing so that they extend into the process fluid.

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同族专利:

公开号 | 公开日

DE102020118184A1|2021-01-14|

US20210010845A1|2021-01-14|

引用文献:

公开号 | 申请日 | 公开日 | 申请人 | 专利标题

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优先权:

申请号 | 申请日 | 专利标题

US16/507,672|US20210010845A1|2019-07-10|2019-07-10|Gwr probe for interface measurement and viscous fluids|

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