Multi-stage irreversible sensor connector

Abstract

The present invention provides a multi-stage irreversible sensor coupling. The sensor body includes a sensor and has a sensor body wall and at least one sensor body engagement feature. The collet is configured to slidably engage the sensor body and has at least one collet engagement feature. The wedge clamp is configured to slidably engage the collet and has at least one wedge clamp engagement feature configured to cause the at least one sensor body engagement feature to cooperatively engage with the at least one collet engagement feature when the wedge clamp, collet, and sensor body are fully engaged.

Description

Technical Field

[0001] The present invention relates to a multi-stage irreversible sensor coupler. Background Art

[0002] The process measurement and control industry uses process variable transmitters to remotely monitor process variables associated with fluids such as slurries, liquids, steam, and gases in chemical, pulp, petroleum, pharmaceutical, food, and other processing plants. Examples of process variables include pressure, temperature, flow, level, turbidity, concentration, chemical composition, pH, gas detection and / or quantification, and other properties.

[0003] Process measurement systems use sensors designed to sense specific variables (such as temperature) and use measurement circuits to sense or determine electrical parameters of the sensors that can be used to calculate process variables. For example, an RTD has a resistance that varies with temperature. The measurement circuit coupled to the RTD can be configured to drive a small current through the RTD and measure the voltage across the RTD. The measured voltage indicates the resistance of the RTD, and therefore the temperature.

[0004] In another example, a gas detection system may employ an electrochemical sensor that provides an electrical response to the presence of a specific gas, such as hydrogen sulfide (H2S). In this case, measurement circuitry provides a suitable electrical excitation to the gas detection sensor in order to measure or otherwise obtain the sensor response.

[0005] Therefore, process measurement systems employ a variety of sensors coupled to appropriate detection electronics. Furthermore, in some cases, sensors may also include sensor electronics that amplify, linearize, or otherwise process the sensor signal before providing it to higher-level electronics in the process measurement system. Consequently, in many process measurement systems, it is necessary to physically and electrically couple the sensor to the sensor measurement electronics or higher-level electronics of the process measurement system. Summary of the Invention

[0006] A multi-stage irreversible sensor coupling is provided. The sensor body includes a sensor and has a sensor body wall and at least one sensor body engagement feature. The collet is configured to slidably engage the sensor body and has at least one collet engagement feature. The wedge clamp is configured to slidably engage the collet and has at least one wedge clamp engagement feature configured to cause the at least one sensor body engagement feature to cooperatively engage with the at least one collet engagement feature when the wedge clamp, collet, and sensor body are fully engaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1is a block diagram of a process measurement system in which embodiments of the present invention are particularly useful.

[0008] Figure 2A is a schematic cross-sectional view of a sensor body coupler according to an embodiment of the present invention.

[0009] Figure 2B is a schematic diagram of a partially assembled sensor body coupler according to an embodiment of the present invention.

[0010] Figure 2C is a schematic diagram of a portion of a partially assembled sensor body coupler according to an embodiment of the present invention.

[0011] Figure 2D is a schematic diagram of an assembled sensor body coupler according to an embodiment of the present invention.

[0012] Figure 2E is a schematic diagram of a portion of a fully assembled sensor body coupler according to an embodiment of the present invention.

[0013] Figure 3 is a schematic cross-sectional perspective view of a portion of a collet and wedge clamp joined together to illustrate one or more anti-rotation features in accordance with an embodiment of the present invention.

[0014] Figure 4 FIG. 1 is an enlarged schematic diagram illustrating a vertical bolt disposed within a channel to prevent rotation according to an embodiment of the present invention.

[0015] Figure 5 is a schematic diagram illustrating a collar of a collet having an anti-rotation lock engaged within an anti-rotation groove of a sensor body according to an embodiment of the present invention.

[0016] Figure 6 is a flow chart of a method of coupling a sensor body to an electronics housing of a process measurement system according to one embodiment. DETAILED DESCRIPTION

[0017] Some process measurement and control systems require that a sensor body or module be physically and electrically attached to an electronic device housing or module. While assembling the sensor body, it is often necessary to use an adhesive to permanently bond the final parts of the assembly. This permanent bonding requires a controlled manufacturing process to ensure the quality of the adhesive joint. Typically, this adds additional (multiple) hours and / or (multiple) days to the system build lead time. Additionally, the sensor sometimes needs to be tested on the final assembly line before the permanent adhesive is applied, and due to operator manipulation of the bonding process, there is a possibility that the internal electrical connections between the sensor body and the electronic device housing will be damaged or otherwise destroyed.

[0018] The embodiments described below generally provide a mechanically permanent coupling between a sensor body and an electronic device housing without the use of permanent adhesives. The embodiments allow for partial assembly of the electrical ends of the sensor body so that the electrical / signal connector attached to the sensor can be wired and tested before the connector is finally coupled to the sensor body during final assembly.

[0019] Figure 1 1 is a block diagram of a process measurement system with which embodiments of the present invention are particularly useful. Process measurement system 100 generally includes an electronics housing 101 coupled to a sensor body 103 at an interface 105. Electronics housing 101 may include a controller 102 capable of executing one or more programmed steps to convert sensor signals received from measurement circuitry 108 into one or more process variable outputs. In some embodiments, controller 102 may be a microprocessor.

[0020] Electronics housing 101 may also include a power module 104 that is coupled to various subcomponents within system 100, as indicated by the arrows labeled "To All." In examples where the system is battery powered, power module 104 may include one or more batteries (rechargeable or non-rechargeable), and appropriate power conditioning circuitry.

[0021] The controller 102 is coupled to a communication circuit 106, which may include any suitable circuitry capable of communicating information about the process variable output(s). As described above, the communication circuit 106 allows the controller 102 to communicate process variable information to a remote device, but may also allow the controller 102 to receive information from one or more remote devices. Suitable examples of such process communications include 4-20mA protocol, Highway Addressable Remote Sensors (HARS), and the like. Agreement, Foundation TM Fieldbus protocol and WirelessHART protocol (IEC62591).

[0022] The measurement circuitry 108 includes any suitable circuitry for determining the electrical response of the sensor 110. For example, the measurement circuitry 108 may include a voltage source or a current source and a suitable amplifier and analog-to-digital converter to read or otherwise interrogate an analog signal from the sensor 110 and provide a digital indication of the analog signal to the controller 102.

[0023] Sensor 110 is disposed within sensor body 103 and has electrical characteristics that vary with the process variable selected for it. For example, sensor 110 may be a temperature sensor or a pressure sensor. In other examples, sensor 110 may be a gas sensor, a pH sensor, a conductivity sensor, etc. Sensor body 103 is coupled to electronics housing 101 via permanent coupling 105. Sensor 110 is electrically coupled to measurement circuitry 108 via permanent coupling 105.

[0024] Figure 2A is a schematic cross-sectional view of a sensor body coupling according to an embodiment of the present invention. A portion of the sensor body is shown at 150 and generally includes a generally cylindrical sidewall 152 having an internal feature 154 configured to engage with a cooperating snap ring or finger 156 on a collet 158. In the illustrated embodiment, the feature 154 includes a recess 155 sized and shaped to receive the finger 156. The sensor body 150 can have any suitable number of electrical interconnect pins that engage cooperating pins of the electronic device housing when the coupling is complete.

[0025] In the example shown, the collet 158 ​​includes one or more anti-rotation features 160, which will be discussed below with reference to the embodiment of the present invention. Figure 3 and Figure 4 1. The anti-rotation feature 160 ensures that the collet 158 ​​cannot rotate relative to the sensor body 150 when the collet 158 ​​and the sensor body 150 are coupled together. As shown, the collet 158 ​​generally also includes a collar 162 having a shoulder portion 164 with a sealing ring 166 (such as an O-ring) disposed around the shoulder portion 164. The wedge clamp 170 is also shown as having a wedge clamp interference feature 172 disposed at the distal end of a sidewall 174. The sidewall 174 is generally cylindrical in shape and extends from the interference feature 172 to a threaded engagement portion (shown as an internally threaded engagement portion 176).

[0026] During assembly, the collet 158 ​​is first moved relative to the sensor body 150 in the direction of arrow 180. As this movement occurs, the engagement features 156 will be positioned proximate to each other, as shown in FIG. Figure 2B As can be seen, the features 154 , 156 are in close proximity to one another but not yet engaged, and the sealing ring 166 seals against the inner surface of the sidewall 152 of the sensor body 150 .

[0027] Figure 2C yes Figure 2B, showing the cooperating features 154, 156 positioned proximate to each other but not yet mechanically engaged. Once the features 154, 156 are positioned proximate to each other but not yet engaged, step one of the coupling assembly is complete.

[0028] Figure 2D The completion of the second step of the coupling assembly is shown. Specifically, the wedge clamp 170 moves relative to the collet 158 ​​in the direction indicated by arrow 180. This movement does not occur until the end engagement feature 172 of the wedge clamp 170 engages the internal wedge portion 182 of the collet 158. The engagement of the end engagement feature 172 and the internal wedge portion 182 causes the cooperating features 154, 156 to engage, thereby completing the multi-step irreversible coupling of the sensor body. Figure 2E is an enlarged view showing the completion of the two-step coupling operation, with the cooperating features 154, 156 engaged together and the interfering features 172 and 182 engaged together. At this point, a permanent mechanical coupling has been created that cannot be disengaged or removed without significant damage to the collet or wedge clamp.

[0029] The two-step assembly process generally provides a wedge-type connection that snaps together in a two-piece assembly. As explained above, the collet 158 ​​and the wedge clamp 170 are assembled in a manner that allows the collet 158 ​​to be ... Figure 2A The cartridge 158 is designed to slide into the sensor body 150 without any interference, as shown in FIG. Figure 2B and Figure 2C The cartridge 158 has engagement features (such as diverging hook-like fingers) that engage the recess of the sensor body, as shown. Figure 2C As shown. The sensor can then be subjected to a final in-line test to confirm a functioning sensor, or calibrated or interacted with in any suitable manner after this first step. Correction of a faulty sensor is also possible at this point in the process. Insertion of the wedge clamp 170 is the second step in the two-piece assembly. At this point, the wedge clamp 170 causes the hooked fingers 156 of the collet 158 ​​to spread apart. The wedge clamp 170 also has a feature 172 that acts as a wedge when engaged with the collet 158, thereby creating a permanent connection, as shown. Figure 2D and Figure 2E As shown. Because the components can be designed for unidirectional movement, the likelihood of the connection breaking during the second step is low. While the connection could be pulled apart with sufficient force, if this were to occur, the design would be rendered useless. Therefore, mechanical connections are considered permanent. This permanent connection can help ensure that the assembly is tamper-resistant, which can be useful for a variety of reasons.

[0030] Figure 3 1 is a schematic cross-sectional perspective view of a portion of a collet and a wedge clamp joined together to illustrate one or more anti-rotation features according to an embodiment of the present invention. As can be seen, one or more longitudinal anti-rotation bolts 190 extend inwardly from the inner surface of the collet 158. These bolts 190 are engaged by suitable grooves 192 of the wedge clamp 170. In this manner, when the wedge clamp 170 is axially inserted into the collet 158, the wedge clamp cannot rotate relative to the collet 158.

[0031] Figure 4 1 is an enlarged schematic diagram showing a vertical bolt 190 disposed within a channel 192 to prevent rotation. These anti-rotation features help ensure that the wires connected to the housing and package circuit board do not twist and break during the assembly process.

[0032] Figure 5 is a schematic diagram illustrating the collar 162 of the collet 158 ​​having anti-rotation tabs 200 that engage within anti-rotation grooves 202 of the sensor body 150 when the collet 158 ​​is engaged with the sensor body 150 .

[0033] While the embodiments described thus far have generally shown specific mechanical features providing snap-fit ​​engagement and / or anti-rotation, it is clearly contemplated that the various collaborations may be reversed and / or alternative mechanical features may be used. Figure 5 In the embodiment shown in , the clamp body 158 may include an anti-rotation groove or channel that is engaged by a tab on the sensor body 150 .

[0034] Figure 6 is a flow chart of a method for coupling a sensor body to an electronics housing of a process measurement system according to one embodiment. Method 300 begins at block 302 where a sensor body, a collet, and a wedge clamp are provided. After completing the steps shown at block 302, preparations such as Figure 2A Next, at block 304, the cartridge is inserted into the sensor body. Once this step is complete, interaction with the sensor can still be performed. For example, the sensor can still be tested to confirm proper function before permanent coupling is completed. Upon completion of step 304, a user can provide information such as Figure 2B Next, at block 306, the wedge clamp is inserted into the clamp barrel. This completes the permanent mechanical connection to the sensor body. Upon completion of step 306, a device such as Figure 2DPreferably, steps 304 and 306 are completed in purely axial motion and do not generate any rotation relative to any particular component. Once the permanent mechanical connection is completed, the connection can be provided with a molded seal or an overmolded seal to prevent leakage, thereby facilitating the replacement of adhesive joint seals.

[0035] While the embodiments described herein are applicable to components made of any suitable material, it is clearly contemplated that embodiments can be practiced in which a single component is molded, where one portion may be semi-stainless steel and another portion may be semi-molded plastic. Alternatively, a single component may be made strictly of stainless steel or any other suitable metal, or strictly of molded plastic or any other suitable polymer. Finally, the dimensions of the coupling may vary depending on the application.

[0036] Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

Claims

1. A multi-stage irreversible sensor connector, comprising: a sensor body having a sensor, the sensor body having a sensor body wall and at least one sensor body engagement feature; a collet configured to slidably engage the sensor body, the collet having at least one collet engagement feature and an internal wedge portion; and a wedge clamp configured to slidably engage the collet, the wedge clamp having at least one wedge clamp engagement feature configured to cause the at least one sensor body engagement feature to cooperatively engage the at least one collet engagement feature via engagement of the at least one wedge clamp engagement feature with the inner wedge portion, Wherein, before the at least one wedge clamp engagement feature engages with the internal wedge portion, the at least one sensor body engagement feature and the at least one cartridge engagement feature are in close proximity to each other but not yet mechanically engaged together, so that an electrical / signal connector attached to the sensor can be wired and tested.

2. The multi-stage irreversible sensor coupler according to claim 1, wherein: The sensor body wall is cylindrical.

3. The multi-stage irreversible sensor coupler according to claim 1, wherein: The at least one sensor body engagement feature includes a recess configured to receive the at least one cartridge engagement feature.

4. The multi-stage irreversible sensor coupler according to claim 1, wherein: The at least one cartridge engagement feature includes a plurality of fingers, each finger having a wedge-shaped end configured to engage the at least one sensor body engagement feature.

5. The multi-stage irreversible sensor coupler according to claim 1, wherein: At least one of the sensor body and the collet is configured to prevent rotation therebetween.

6. The multi-stage irreversible sensor coupler according to claim 1, wherein: At least one of the collet and the wedge clamp is configured to prevent rotation therebetween.

7. The multi-stage irreversible sensor coupler according to claim 1, wherein: The sensor is selected from the group consisting of a temperature sensor, a pressure sensor, a gas sensor, a pH sensor, and a conductivity sensor.

8. The multi-stage irreversible sensor coupler according to claim 1, wherein: The at least one wedge clamp engagement feature includes a wedge clamp interference feature at a distal end of the wedge clamp, the at least one wedge clamp engagement feature forming a wedge when engaged with the at least one collet engagement feature.

9. The multi-stage irreversible sensor coupler according to claim 1, wherein: The wedge clamp has a cylindrical sidewall configured to be slidably received within the clamp barrel.

10. The multi-stage irreversible sensor coupler according to claim 1, wherein: The wedge clamp includes a threaded portion disposed on an end of the wedge clamp opposite the at least one wedge clamp engagement feature.

11. The multi-stage irreversible sensor coupler according to claim 1, wherein: The collet includes a collar configured to abut the sensor body when the collet and sensor body are fully engaged.

12. The multi-stage irreversible sensor coupler according to claim 11, wherein: The collet includes a shoulder portion proximate the collar, the shoulder portion having a sealing element disposed thereabout.

13. A process variable measurement system comprising: a sensor disposed within a sensor body; A controller, the controller being disposed in a housing of the electronic device; and a measurement circuit electrically coupled to the sensor, the measurement circuit disposed within the electronic device housing and coupled to the controller, the measurement circuit configured to measure an electrical characteristic of the sensor and provide a digital indication of the electrical characteristic to the controller, The electronic device housing and the sensor body are coupled together by the multi-stage irreversible sensor coupler according to any one of claims 1 to 12.

14. The process variable measurement system according to claim 13, wherein: The process variable measurement system also includes communication circuitry coupled to the controller, the communication circuitry configured to provide an indication of a process variable to a remote device based on an electrical characteristic of the sensor.

15. The process variable measurement system according to claim 13, wherein: The multi-stage irreversible sensor coupling is overmolded with a seal.

16. The process variable measurement system according to claim 15, wherein: The seal is a polymer seal.

17. A method of manufacturing a multi-stage irreversible sensor coupling according to any one of claims 1 to 12, the method comprising: providing a sensor body having a sensor; Provide a collet; Provide wedge clamps; axially moving the collet relative to the sensor body until a collar of the collet contacts an end of the sensor body; axially moving the wedge clamp relative to the collet until a wedge clamp interference feature at a distal end of the wedge clamp engages an internal wedge portion of the collet, After axially moving the cartridge relative to the sensor body but before axially moving the wedge clamp relative to the cartridge, electrical / signal connectors attached to the sensor are wired and tested while the sensor body and cartridge are in close proximity to each other but not yet mechanically engaged.

18. The method according to claim 17, further comprising: Prevents rotation during axial movement.

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