Condition detection of pressure transmitter diaphragm

Abstract

To provide an art generally relating to a failure detection device in a pressure transmitter, particularly a failure detection device in a pressure transmitter utilizing a diaphragm.SOLUTION: A material property sensor for a pressure transmitter includes a sensing pattern immersed in a fill fluid. The pressure transmitter includes a diaphragm configured for contact with a process fluid at an exterior surface of the diaphragm. In addition, the pressure transmitter includes a pressure sensor configured for sensing a pressure of the process fluid on the diaphragm. The pressure sensor and the diaphragm define a cavity within which the fill fluid is disposed so that the diaphragm of the pressure sensor contacts the fill fluid at an interior surface of the diaphragm. The sensing pattern is immersed in the fill fluid within the cavity, and configured to measure an electrical property of the fill fluid at an initial time and at one or more subsequent times during operation of the pressure transmitter.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure generally relates to a fault detection device in a pressure transmitter, and more particularly to a fault detection device in a pressure transmitter that utilizes a diaphragm.

Background Art

[0002] Pressure sensors are used in a variety of applications that rely on accurate and stable pressure measurements in order to operate reliably. As industries that rely on pressure sensors increase to monitor and control those applications, the demand for these sensors has increased significantly. Along with varying effectiveness and convenience, there are a variety of pressure sensor designs. In particular, pressure sensors that utilize diaphragms made of thin materials have become widespread.

Summary of the Invention

[0003] Aspects of the present disclosure enable the detection of the state of a diaphragm of a pressure transmitter. The detected state may represent an actual or predicted diaphragm failure due to cracking, leakage, or other damage to the diaphragm.

[0004] In one aspect, a material property sensor for a pressure transmitter includes a sensing pattern immersed in a filling fluid. The pressure transmitter includes a diaphragm configured to contact a process fluid at an outer surface of the diaphragm. The pressure transmitter further includes a pressure sensor configured to sense the pressure of the process fluid on the diaphragm. The pressure sensor and the diaphragm define a cavity in which the filling fluid is disposed such that the diaphragm of the pressure sensor contacts the filling fluid at an inner surface of the diaphragm. The sensing pattern is immersed in the filling fluid in the cavity and is configured to measure an electrical property of the filling fluid at an initial time and at one or more subsequent times during operation of the pressure transmitter.

[0005] In another embodiment, a method for detecting a changed state of a pressure transmitter utilizes a pressure transmitter comprising a diaphragm configured to contact a process fluid on the outer surface of the diaphragm. The pressure transmitter further comprises a pressure sensor configured to sense the pressure of the process fluid on the diaphragm. The method includes measuring one or more properties of a filling fluid in which a sensing pattern is immersed over a range of temperature and pressure in an initial time. The method further includes characterizing a fingerprint of the filling fluid as a function of one or more dielectric properties measured in the initial time, and measuring one or more dielectric properties of the filling fluid in subsequent time. The method also includes characterizing the current behavior of the filling fluid as a function of one or more properties, pressure and temperature measured in subsequent time, detecting a change in one or more properties of the filling fluid over time by comparing the current behavior of the filling fluid in subsequent time with the fingerprint of the filling fluid in initial time, and generating an alert using an alert circuit in response to the difference between the material properties of the filling fluid in subsequent time and the material properties of the filling fluid fingerprint measured for the first time when the difference exceeds a threshold.

[0006] In yet another embodiment, the pressure transmitter comprises a diaphragm configured to contact a process fluid on its outer surface, a pressure sensor configured to sense the pressure of the process fluid on the diaphragm, and a filling fluid. The diaphragm of the pressure sensor is in contact with the filling fluid on its inner surface, and the pressure sensor and diaphragm define a cavity in which the filling fluid is placed. The pressure transmitter further comprises a sensing pattern immersed in the filling fluid within the cavity and configured to measure the electrical properties of the filling fluid at an initial time and at one or more subsequent times during the operation of the pressure transmitter.

[0007] Other purposes and features of this disclosure are partially evident and partially pointed out herein. [Brief explanation of the drawing]

[0008] [Figure 1] This is a front view of a pressure transmitter according to one embodiment. [Figure 2] This is a cross-section of the pressure transmitter taken along the plane extending along line 1-1 in Figure 1. [Figure 3] This is a cross-section of the pressure transmitter sensor assembly taken in a plane extending along line 1-1 in Figure 1. [Figure 4] Figure 3 is a top view of the sensing pattern of the material property sensor in the sensor assembly. [Figure 5] This is a circuit diagram of a Wheatstone bridge circuit for use with the pressure transmitter shown in Figure 1. [Modes for carrying out the invention]

[0009] The corresponding reference numbers indicate the corresponding parts throughout the drawing.

[0010] Referring to Figure 1, a pressure transmitter 100 according to one embodiment of the present disclosure comprises a transparent cover 114, a user display housing 104, and a user display 102 (e.g., an LDC display) configured behind the sensor housing 106. The user display housing 104 has an opening through which the user display 102 can be viewed. In the illustrated embodiment, the pressure transmitter 100 is attached to a fluid source such as a wellhead or an oil pump, which supplies process fluid through a pipe to measure the pressure of the fluid in the pipe. However, the pressure transmitter 100 is not limited to fluid pump applications. The pressure transmitter 100 can also be used in industrial, chemical, automotive, medical, consumer, and residential applications, among others.

[0011] Referring to Figure 2, a cross-section of the pressure transmitter 100 shows the internal components of the pressure transmitter. As shown in Figure 2, the pressure transmitter 100 further comprises a user terminal block 108, a user terminal block housing 110, a controller 112, a sensor assembly 116, and electronic wiring 118. The sensor housing 106 has a front opening, a rear opening, and a bottom opening, the front opening configured to receive the user display housing 104, the rear opening configured to receive the user terminal block housing 110, and the bottom opening configured to receive the sensor assembly 116. The transparent cover 114 is configured to be received within the user display housing 104 between the opening of the user display housing and the user display 102.

[0012] Referring to Figure 3, the sensor assembly 116 further comprises a chip carrier 120, a material property sensor 122, and a diaphragm 124. In one embodiment of the present disclosure, the chip carrier 120 is made of a ceramic material. The chip carrier 120 is further configured to support a pressure sensor 126.

[0013] In the embodiments shown in Figures 2 and 3, the diaphragm 124 is made of a metallic material (e.g., stainless steel, Inconel® or other nickel-chromium-based superalloys, Haynes® 242® or other nickel-chromium-molybdenum alloys, Hastelloy® or other nickel-molybdenum alloys, titanium, or Monel). However, the diaphragm is not limited to a metallic material. As shown in Figures 2 and 3, the pressure transmitter 100 includes a single diaphragm 124, but it should be understood that aspects of this disclosure may apply to pressure transmitters having multiple diaphragms.

[0014] In the illustrated embodiment, the diaphragm 124 defines a cavity 130 between the diaphragm and the chip carrier, spaced apart from the pressure sensor 126 and the chip carrier 120. A filling fluid 132 is placed within the cavity 130 and is composed of an incompressible material (e.g., Silicone 200DC10 or other silicone fluid, Fluorinert® FC43 or other fluorinated aliphatic fluid, water, or Neobee N1260TZ). The diaphragm 124 is in contact with the filling fluid 132 at its inner surface 133. The sensor assembly 116 is selectively mountable to the user application such that the diaphragm 124 is configured to contact the process fluid 134 at its outer surface 135. In a preferred embodiment, the filling fluid 132 is a different fluid from the process fluid 134, and the filling fluid and the process fluid have different dielectric properties. The material property sensor 122 further comprises a sensing pattern 136. The material property sensor 122 and its sensing pattern 136 are configured to be immersed in the filling fluid 132, enabling the material property sensor to measure the electrical properties of the filling fluid, such as conductivity, leakage current, resistivity, dielectric constant, and dielectric constant. As shown in the figure, the material property sensor 122, including the sensing pattern 136, is located on the surface of the chip carrier 120.

[0015] As shown in Figure 4, the sensing pattern 136 in the illustrated embodiment consists of two generally comb-shaped structures 137 and 139, rotated 90 degrees to define comb teeth 141 having horizontal segments 138 and vertical segments 140. In this embodiment, the horizontal segments 138 are spaced 0.0060 inches apart from each other and have a length of 0.0120 inches, while the width of the sensing pattern circuit 137 is 0.0030 inches. In this embodiment, the width of the sensing pattern 136 is 0.0270 inches. In the illustrated embodiment, the distance between the sensing pattern circuit 137 and the side edge of the sensing pattern 136 is 0.0060 inches, while the distance between the upper and lower ends of the sensing pattern 136 and the sensing pattern circuit 137 is 0.0230 inches. The comb-shaped structures 137 and 139 are composed of conductive elements and together form a capacitor. The filling fluid 132 acts as a dielectric between the two conductive elements, and the measured change in capacitance can be used to detect the dielectric constant of the filling fluid 132. In an alternative embodiment of the sensing pattern 136, the teeth 141 would have horizontal segments 138 having a length greater than 0.0120 inches. The comb structures 137, 139 are configured to favorably maximize coupling.

[0016] Figure 5 shows an exemplary circuit diagram embodying a further embodiment of the pressure transmitter 100 in the form of a Wheatstone bridge 150. As shown in Figure 5, the Wheatstone bridge circuit 150 comprises a temperature bridge 152 and a pressure bridge 154. As an alternative to or addition to the sensing pattern 136, the Wheatstone bridge circuit 150 is configured to measure the material properties of the filling fluid 132 by determining the resistance when a voltage is applied to the bridge circuit. For example, the bridge circuit 150 can float to measure resistance. A current is injected into pin 9 of the temperature bridge 152, and then the voltage is read between pins 9 and 2 of the pressure bridge 154. The voltage measurement indicates the resistance of the filling fluid 132. Similarly, the voltage can be read across a floating bridge circuit of a single variable transmitter having a single bridge circuit for determining the resistance of the filling fluid 132. In this embodiment, the sensing pattern 136 comprises a Wheatstone bridge circuit.

[0017] During operation, the pressure transmitter 100 is configured to sense the pressure of the process fluid 134. When the process fluid 134 is pressurized as part of the process, the process fluid exerts a force on the diaphragm 124. The diaphragm 124 is configured to be thin enough to deflect in response to the pressure applied by the process fluid 134. The deflection of the diaphragm 124 exerts a force on the incompressible filling fluid 132, which transmits the force to the pressure sensor 126. As a result of the transmission of these forces, the pressure sensor 126 measures the pressure change caused by the process fluid 134 on the outer surface of the diaphragm 124. The pressure sensor 126 is configured to generate an electronic signal in response to the force applied to the pressure sensor (i.e., piezoelectric or strain gauge response). The electrical signal is transmitted from the pressure sensor 126 to the controller 112 via the electrical connection 118. The controller 112 receives the electrical signal and outputs the pressure measurement value, which is displayed on the user display 102. Furthermore, the user terminal block 108 provides input / output terminals for connecting the pressure transmitter 100 to an external circuit.

[0018] While the pressure transmitter 100 performs its function of reading the pressure of the process fluid 134, the material property sensor 122 simultaneously performs measurements of the filling fluid 132 to test the material properties of the filling fluid. As described above, the material property sensor 122 is immersed in the filling fluid 132. At an initial time (t1), the material property sensor 122 measures the electrical properties of the filling fluid using a sensing pattern 136. In one embodiment of this disclosure, the material property sensor 122 can measure the conductivity, leakage current, resistivity, dielectric constant, and dielectric constant of the filling fluid 132. However, this application should not be interpreted as limiting the material properties of the filling fluid 132 that the material property sensor 122 can measure.

[0019] To measure the conductivity, leakage current, resistivity, or dielectric constant of the filling fluid 132 at t1, a known voltage is applied across a sensing pattern 136 with a known resistance while immersed in the filling fluid. To measure the dielectric constant of the filling fluid 132 at t1, a voltage is applied across the sensing pattern 136 at one or more frequencies through a known capacitor while immersed in the filling fluid. The sensing pattern 136 is configured to measure the dielectric properties of the filling fluid 132 over a range of temperature and pressure to create a filling fluid fingerprint associated with the dielectric properties at t1. By measuring one or more material properties of the filling fluid 132 over a range of temperature and pressure at t1, the filling fluid fingerprint can determine values ​​associated with specific properties at individual temperatures and pressures.

[0020] Since the pressure transmitter 100 operates over time, the forces of the process fluid 134 on the diaphragm 124, as well as chemical, mechanical, and / or external factors, can cause cracks or leaks, for example, which can contribute to the ultimate failure of the diaphragm 124. When the diaphragm fails, the sensor 126 can continue to operate in a degraded state for some time. This degraded performance can lead to undesirable inaccurate pressure measurements for its application. If not corrected, an incorrect measurement of the pressure of the process fluid 134 can lead to unnecessary corrective actions or a delay in necessary corrective actions, resulting in higher costs or product losses for the user.

[0021] When the diaphragm 124 fails, the fill fluid 132 can be contaminated by debris or mixed with the process fluid 134. When the fill fluid 132 is contaminated, this contamination causes a change in the measured material properties of the fill fluid. Some common values for some of the possible fill fluids described above can be seen in Table 1 shown below. [Table 1]

[0022] The material property sensor 122 is configured to measure changes in the material properties of the filling fluid 132 by continuously measuring them over one or more subsequent time intervals tn during the operation of the pressure transmitter 100. The material property sensor 122 is configured to continuously monitor conductivity, leakage current, resistivity, and / or dielectric constant by applying a voltage across a sensing pattern 136 with a known resistance. Alternatively, the material property sensor 122 is configured to continuously monitor the dielectric constant of the filling fluid 132 by applying a known voltage across a sensing pattern 136 at one or more frequencies via a known capacitor. The material property sensor 122 can use the filling fluid fingerprint to determine if appropriate values ​​for the material properties of the filling fluid 132 (e.g., conductivity, resistivity, dielectric constant, leakage current, or dielectric constant) are present at a given temperature and pressure. These values ​​are then compared to measured values ​​of the material properties to determine if the values ​​match within a predetermined threshold. In one embodiment, the controller 112 of the pressure transmitter 100 generates an alert in response to the difference between the material properties of the filling fluid 132 at a subsequent time tn and the material properties of the filling fluid fingerprint measured at the first time t1 when the difference exceeds a threshold. This alert notifies the user that the filling fluid 132 may be contaminated in some way, such as a failure of the diaphragm 124, and thereby notifies the user that the diaphragm needs to be replaced.

[0023] Next, an exemplary method for detecting the changed state of the pressure transmitter as described above will be briefly described below. The pressure transmitter 100 includes a diaphragm 124 configured to contact the process fluid 134 on the outer surface of the diaphragm. The pressure transmitter 100 further includes a pressure sensor 126 configured to sense the pressure of the process fluid 134 on the diaphragm 124. The method includes a first step of measuring one or more properties of the fill fluid 132 at an initial time t1, where, for example, the sensing pattern 136 of the Wheatstone bridge circuit is immersed over a range of temperature and pressure. In one embodiment, the sensing pattern 136 is disposed on the chip carrier 120, which is preferably made of a ceramic material. The pressure sensor measures the change in pressure caused by the process fluid 134 on the outer surface of the diaphragm 124. Dielectric properties can include, but are not limited to, conductivity, leakage, permittivity, resistivity, and dielectric constant. To measure the conductivity, leakage, resistivity, or permittivity of the fill fluid 132 at t1, a known voltage is applied across the sensing pattern 136 with a known resistance. To measure the dielectric constant of the fill fluid 132 at t1, a voltage is applied across the sensing pattern 136 at one or more frequencies through a known capacitor. In a preferred embodiment of the present disclosure, the fill fluid 132 is a fluid different from the process fluid 134, and the fill fluid and the process fluid have different dielectric properties.

[0024] In a second step, the method embodying aspects of the present disclosure includes characterizing the fingerprint of the fill fluid 132 as a function of one or more dielectric properties measured at the initial time t1. By measuring one or more material properties of the fill fluid 132 over a range of temperature and pressure at t1, the fingerprint of the fill fluid can be determined as a value associated with specific properties at individual temperatures and pressures.

[0025] In the third step, the method includes measuring one or more dielectric properties of the filling fluid 132 during the operation of the pressure transmitter 100 over one or more subsequent time intervals tn. In the fourth step, the method includes characterizing the current behavior of the filling fluid 132 as a function of one or more properties, pressure, and temperature measured over subsequent time intervals. By collecting temperature and pressure data from the sensor assembly 116, the material property sensor 122 can use the filling fluid fingerprint to determine what appropriate values ​​for the material properties of the filling fluid 132 (e.g., conductivity, resistivity, dielectric constant, leakage current, or dielectric constant) should be at specific temperatures and pressures.

[0026] In the fifth step, the method includes comparing the current behavior of the filling fluid 132 at a subsequent time tn with the fingerprint of the filling fluid at an initial time t1 in order to detect a change in one or more properties of the filling fluid over time. This value is then compared with a measured material property to determine whether the values ​​match within a predetermined threshold.

[0027] In the sixth step, the method includes generating an alert using an alert circuit in response to the difference between the material properties of the filling fluid 132 at a subsequent time tn and the material properties of the filling fluid fingerprint measured at an initial time t1 when the difference exceeds a predetermined threshold. This alert notifies the user that the filling fluid 132 may be contaminated in some way, such as a failure of the diaphragm 124, and thereby notifies the user that the diaphragm needs to be replaced.

[0028] In embodiments of the embodiments of the present invention illustrated and described herein, the order in which the operations are performed or carried out is not essential unless otherwise specified. That is, the operations can be performed in any order unless otherwise specified, and embodiments of the embodiments of the present invention may include additional or fewer operations than those disclosed herein. For example, performing or carrying out a particular operation before, simultaneously with, or after another operation is considered to be within the scope of embodiments of the present invention.

[0029] When introducing elements of aspects or embodiments of the present invention, the articles "a," "an," "the," and "said" are intended to indicate the presence of one or more elements. The terms "comprising," "including," and "having" are intended to be comprehensive and mean that additional elements other than those listed may exist.

[0030] Not all illustrated components illustrated or described are necessarily required. Furthermore, some embodiments and designs may include additional components. Modifications to the arrangement and type of components can be made without departing from the spirit or scope of the claims set forth herein. Additional, different, or fewer components may be provided, and components may be combined. Alternatively or in addition, components may be implemented by several components.

[0031] The above description is illustrative of embodiments of the present invention, not limiting. This description describes several embodiments, adaptations, modifications, substitutions, and uses of embodiments of the present invention, including those considered to be the best modes for current practice, enabling those skilled in the art to create and use embodiments of the present invention. Furthermore, it should be understood that embodiments of the present invention are not limited to the configuration details and arrangement of components described or shown in the drawings in the application. Other embodiments of the present invention are possible and can be practiced or implemented in various ways. Also, it should be understood that the expressions and terms used herein are for illustrative purposes only and should not be considered limiting.

[0032] It will be apparent that modifications and variations are possible without departing from the scope of the invention as defined in the attached claims. Since various changes can be made to the above configuration and method without departing from the scope of the invention, all matters included in the above description and shown in the attached drawings are intended to be interpreted as illustrative, not restrictive.

[0033] Considering the above, it will be seen that some advantages of the embodiments of the present invention are achieved, and other favorable results are attained.

[0034] The abstract and summary of the invention are provided to allow readers to quickly grasp the nature of the technical disclosure. They are presented with the understanding that they are not to be used to interpret or limit the claims or their meaning. The summary of the invention is provided to introduce, in a simplified form, a selection of concepts that are further described in the detailed description. The summary of the invention is not intended to identify the main or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the claimed subject matter.

Claims

1. 1. A material property sensor for a pressure transmitter, the pressure transmitter comprising a diaphragm configured to contact a process fluid at an outer surface of the diaphragm, the pressure transmitter further comprising a pressure sensor configured to sense a pressure of the process fluid on the diaphragm, the material property sensor comprising: a fill fluid, the diaphragm of the pressure sensor being in contact with the fill fluid on an inner surface of the diaphragm, the pressure sensor and the diaphragm defining a cavity in which the fill fluid is disposed; and a sensing pattern immersed in the fill fluid within the cavity and configured to measure a dielectric property of the fill fluid at an initial time and at one or more subsequent times during operation of the pressure transmitter; 1. A material property sensor comprising:

2. The material property sensor of claim 1 , wherein the fill fluid is an incompressible fluid.

3. 3. The material property sensor of claim 1 or 2, wherein the fill fluid is a different fluid than the process fluid, and the fill fluid and the process fluid have different dielectric properties.

4. 3. The material property sensor of claim 1 or 2, wherein the sensing pattern is configured to measure electrical properties of the fill fluid over a range of temperatures and pressures to create a fill fluid fingerprint associated with the electrical properties, the electrical properties including at least one of conductivity, resistivity, leakage current, and dielectric constant.

5. 5. The material property sensor of claim 4, further comprising an alarm circuit for generating an alert in response to the difference between a material property of the fill fluid at the subsequent time and a material property of the fill fluid fingerprint measured at the initial time when the difference exceeds a threshold value.

6. The sensing pattern is the electrical properties of the fill fluid by applying a known voltage across the sensing pattern through a known resistance to create the fill fluid fingerprint; the dielectric constant of the fill fluid by applying a known voltage across the sense pattern at one or more frequencies via a known capacitor to create the fill fluid fingerprint associated with the dielectric constant; The material property sensor of claim 4 configured to measure at least one of:

7. A pressure transmitter comprising the material property sensor according to claim 1 or 2.

8. 1. A method of detecting a changed state of a pressure transmitter, the pressure transmitter comprising a diaphragm configured to contact a process fluid at an outer surface of the diaphragm, the pressure transmitter further comprising a pressure sensor configured to sense a pressure of the process fluid on the diaphragm; measuring, at an initial time, one or more properties of a fill fluid in which the sensing pattern is immersed over a range of temperatures and pressures; characterizing a fingerprint of the fill fluid as a function of one or more dielectric properties thereof measured at the initial time; measuring the one or more dielectric properties of the fill fluid at a subsequent time; and characterizing the current behavior of the fill fluid as a function of the one or more properties, pressure and temperature thereof measured at the subsequent time; comparing the current behavior of the fill fluid at the subsequent time to a fingerprint of the fill fluid at the initial time to detect changes in the one or more properties of the fill fluid over time; generating an alert using an alert circuit in response to the difference between the material property of the fill fluid at the subsequent time and the material property of the fingerprint of the fill fluid measured for the first time when the difference exceeds a threshold value; A method comprising:

9. The method of claim 8 , wherein the fill fluid is a different fluid than the process fluid, and the fill fluid and the process fluid have different dielectric properties.

10. 10. The method of claim 8 or claim 9, further comprising creating a fill fluid fingerprint with the sensing pattern, the fill fluid fingerprint being associated with at least one of a measured electrical characteristic of the fill fluid by applying a known voltage across the sensing pattern through a known resistance, and a measured dielectric constant of the fill fluid by applying a known voltage across the sensing pattern through a known capacitance at one or more frequencies.

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