Automatic determination of trigger angle for reciprocating compressor rod drop measurements

Abstract

This invention relates to a machine monitoring system that automatically determines an optimal trigger angle for monitoring the rod descent of a reciprocating compressor and accordingly sets a trigger angle configuration value. Key pulses are monitored using a key phase sensor, the amplitude of the rod descent transducer voltage relative to time (or rotation angle) is analyzed, and the position of minimum change in the slope of the rod descent transducer voltage signal relative to the key mark is determined. The optimal trigger angle is determined based on the current time position, current speed, and configured piston angle. The optimal trigger angle is provided to the machine monitoring system for configuration. The system eliminates the need for service engineers to manually operate test instruments to test several trigger angles to determine the optimal trigger angle.

Description

Technical Field

[0001] This invention relates to the field of online machine protection systems. More particularly, this invention relates to a machine monitoring system that automatically determines the optimal trigger angle for monitoring industrial reciprocating compressors and sets appropriate configuration values ​​accordingly. Background Technology

[0002] According to API standard 670 regarding mechanical protection systems, most horizontal reciprocating compressors rely on a piston rider band to support the piston and prevent contact with the cylinder liner. As these bands wear, the piston rod descends within the cylinder and moves a corresponding amount within the rod packing material. Monitoring the amount of rod descent is one way to sense the wear of the piston rider band.

[0003] Monitoring systems used for mechanical protection typically monitor the rod descent of reciprocating compressors using two modes: averaging mode and trigger mode. Averaging mode calculates the measurement based on the average of multiple sample values ​​of the piston stroke. Trigger mode utilizes only one value at a specified position on the piston rod. This position is determined by two angle values ​​that must be configured for the monitoring system: the piston angle and the trigger angle.

[0004] like Figure 1 As shown, when the piston is at top dead center (TDC), the piston angle is the degree between the key trigger mark on the flywheel and the phase reference transducer. The piston angle can be measured directly at the reciprocating compressor, and in some cases, can be read from the compressor technical data in the manufacturer's operating manual.

[0005] Trigger angle (also shown in) Figure 1 The trigger angle (in Chinese) has been routinely determined and set based on field testing of the machine. According to API 670: "To properly use the trigger mode, find the point in the stroke where the gap voltage variation due to all effects other than support belt wear is minimized. This is done through field testing during the commissioning of the piston rod drop monitor." Typically, service engineers must test several trigger angle values ​​to determine the correct trigger angle for a specific reciprocating compressor. This testing requires the use of various manually operated measuring tools (oscilloscopes, voltmeters, throttle counters, etc.) to calculate the trigger angle based on the voltage output of the rod drop converter and the machine speed. This testing and calculation requires significant expertise and is prone to error.

[0006] Therefore, what is needed is a device and method for automatically determining the optimal trigger angle for rotating machines (such as reciprocating compressors) without the need for manually operated measuring tools. Summary of the Invention

[0007] The above and other requirements are met by a machine monitoring system that automatically determines the optimal trigger angle and sets the appropriate configuration value accordingly. This system eliminates the need for service engineers to manually operate testing instruments to test several trigger angles to determine the correct one. Service engineers can simply verify the determined configuration settings and reconfigure the machine monitoring system with the new trigger angle, or accept automatic entry into the configuration settings for the trigger angle.

[0008] In a preferred embodiment, the machine monitoring system determines the trigger angle as needed only when the reciprocating compressor is operating in a stationary mode. The key pulse is calculated based on the key phase sensor of the reciprocating compressor via the speed / key monitor of the machine monitoring system. Based on the machine's key pulse and speed, the amplitude of the lever drop converter voltage relative to time (or rotation angle) is checked, and a temporary position is determined, which represents the key marker of the minimum change in the slope of the lever drop converter voltage signal. From this time position, the optimal trigger angle is determined based on the current speed and configured piston angle. This optimal trigger angle is provided to the machine monitoring system for configuration.

[0009] Some preferred embodiments relate to a machine monitoring system for acquiring operational information about a machine having a piston rod and a rotating component connected to the rotating component. The system includes a rod position sensor and a rod position monitoring circuit, the rod position sensor being mounted adjacent to the piston rod, and the rod position monitoring circuit communicating with the rod position sensor. During machine operation, the rod position sensor generates a rod position voltage signal indicating the proximity of the piston rod relative to the rod position sensor. The position monitoring circuit includes one or more analog-to-digital converters for sampling the rod position voltage signal and converting it into digital rod position data. The rod position monitoring circuit also includes a processor operable to execute operational instructions for processing the digital rod position data. The operational instructions include instructions that:

[0010] —Determine the rotational speed of the machine's rotating parts;

[0011] —Detect the complete rotation of the rotating parts of the machine;

[0012] — Multiple slope values ​​of the rod position voltage signal are determined based on digital rod position data, wherein the slope values ​​are calculated sample by sample during the full rotation of the rotating component, and each slope value indicates the slope of the rod position voltage signal between adjacent data samples;

[0013] —Find multiple ranges of consecutive slope values ​​within multiple slope values, where each slope value falls within a predetermined amplitude range about zero slope;

[0014] —Determine the widest range of consecutive slope values ​​within a range, where the widest range has the maximum number of consecutive slope values;

[0015] —Determine the rotation angle corresponding to the widest range of rotating components; and

[0016] The trigger angle is calculated based on the rotation angle using the following formula: Trigger angle = Rotation angle + Piston angle; where the piston angle is a predetermined stored value; and

[0017] The system includes a memory for storing trigger angle configuration values, which correspond to trigger angles calculated by a processor.

[0018] In some embodiments, the processor determines the midpoint within the widest range and determines the rotation angle corresponding to that midpoint.

[0019] In some embodiments, the widest range of continuous slope values ​​has a starting slope value and an ending slope value, wherein the starting slope value corresponds to a starting angle or a starting time, wherein the ending slope value corresponds to an ending angle or an ending time, and wherein the rotation angle determined by the processor corresponds to the midpoint angle between the starting angle and the ending angle, or corresponds to the midpoint time between the starting time and the ending time.

[0020] In some embodiments, after calculating the trigger angle, the processor continuously monitors the piston rod descent in trigger mode based on the rod position voltage determined by the calculated trigger angle.

[0021] In some embodiments, the machine monitoring system includes a display device and an input device. The display device shows a calculated trigger angle for user observation. The input device receives input from the user to select a trigger angle configuration value corresponding to the trigger angle calculated by the processor, or to select a predetermined trigger angle configuration value stored in memory.

[0022] In some embodiments, the rod position sensor includes a proximity transducer mounted adjacent to the piston rod.

[0023] In some embodiments, the machine monitoring system includes a key phase sensor mounted near the rotating component, the key phase sensor being used to generate a key phase voltage signal having pulses corresponding to the rotation of the rotating component.

[0024] In another aspect, the present invention provides a method for obtaining information about the operation of a machine having a piston rod and a rotating component, the piston rod being connected to the rotating component. The method includes:

[0025] (a) A rod position voltage signal is generated using a rod position sensor mounted adjacent to the piston rod, wherein the rod position voltage signal indicates the degree of proximity of the piston rod relative to the rod position sensor during operation of the machine;

[0026] (b) Sample the pole position voltage signal and convert the pole position voltage signal into digital pole position data;

[0027] (c) Determine the rotational speed of the rotating parts of the machine;

[0028] (d) Detect the complete rotation of the rotating parts of the machine;

[0029] (e) Determine multiple slope values ​​of the rod position voltage signal based on digital rod position data, wherein the slope values ​​are calculated sample by sample during the full rotation of the rotating component, and each slope value indicates the slope of the rod position voltage signal between adjacent data samples;

[0030] (f) Find multiple ranges of consecutive slope values ​​within multiple slope values, wherein each slope value is within a predetermined amplitude range about zero slope;

[0031] (g) Determine the widest range of consecutive slope values ​​within a plurality of ranges, wherein the widest range has the maximum number of consecutive slope values;

[0032] (h) Determine the rotation angle of the rotating component corresponding to the widest range determined in step (g);

[0033] (i) Calculate the trigger angle based on the rotation angle according to the following formula: Trigger angle = Rotation angle + Piston angle, where the piston angle is a predetermined stored value; and

[0034] (j) Store the trigger angle configuration value in a memory device, wherein the trigger angle configuration value corresponds to the trigger angle calculated in step (i).

[0035] In some embodiments, step (h) includes determining the midpoint of the widest range determined in step (g) and determining the rotation angle corresponding to the midpoint.

[0036] In some embodiments, the widest range determined in step (g) has a starting slope value and an ending slope value, wherein the starting slope value corresponds to a starting angle or a starting time, wherein the ending slope value corresponds to an ending angle or an ending time, and wherein the rotation angle corresponds to the midpoint angle between the starting angle and the ending angle, or corresponds to the midpoint time between the starting time and the ending time.

[0037] In some embodiments, the method includes continuously monitoring the rod descent of the piston rod in a trigger mode based on the rod position voltage determined at the trigger angle calculated in step (i).

[0038] In some embodiments, the method includes displaying the trigger angle calculated in step (i) for user observation, and receiving input from the user for selection:

[0039] —The trigger angle configuration value corresponding to the trigger angle calculated in step (i); or

[0040] —A predetermined trigger angle configuration value stored in a memory device. Attached Figure Description

[0041] Other embodiments of the invention will become apparent from the detailed description taken in conjunction with the accompanying drawings, wherein elements are not drawn to scale to show details more clearly, wherein similar reference numerals indicate similar elements in several views, and wherein:

[0042] Figure 1 An exemplary position of a phase reference transducer and a rod drop position transducer relative to the flywheel, piston rod, and crankshaft of a machine (such as a reciprocating compressor) is shown in one embodiment of the invention.

[0043] Figure 2 A machine monitoring system is illustrated according to an embodiment of the present invention;

[0044] Figure 3 According to an embodiment of the present invention, the first part of a process performed by a machine monitoring system is shown;

[0045] Figure 4 According to an embodiment of the invention, a second part of the process performed by a machine monitoring system is shown; and

[0046] Figure 5 An exemplary graph of the rod drop voltage signal relative to the flywheel rotation angle is shown in one embodiment of the present invention. Detailed Implementation

[0047] Figure 2 An exemplary machine monitoring system 10 is shown for automatically determining the optimal trigger angle for rotating machines (such as reciprocating compressors) and setting appropriate configuration values ​​for the trigger angle. Figure 2 In the illustrated embodiment, the rod position sensor 12 (such as a proximity transducer) is mounted vertically (at a 90-degree angle) below or above the piston rod, as close as possible to the compressor cylinder. The sensor 12 generates a voltage signal that indicates the range of vertical movement of the piston rod relative to the sensor 12 during continuous operation of the compressor.

[0048] A key phase sensor 14 (which may be an eddy current proximity transducer, a Hall effect sensor, an optical pickup, or a magnetic pickup) is mounted close to the flywheel. The sensor 14 is positioned such that it detects a keyway marking (such as an elongated cut) etched into the flywheel during each rotation of the flywheel. As the flywheel rotates, the sensor 14 generates a key phase voltage signal with pulses corresponding to each keyway detection. It should be understood that the key phase voltage signal can also be generated by additional / separate monitoring circuitry, and it can be provided as an analog or digital signal. Therefore, embodiments of the invention are not limited to any particular source or format of the key phase voltage signal.

[0049] The pole drop voltage signal and the key phase voltage signal are provided to the pole drop monitoring card 16, which preferably includes analog-to-digital converters (ADCs) 18 and 20 for sampling the pole drop signal and the key phase voltage signal, a computer processor 22 for processing the pole drop data and the key phase voltage data, a memory 24 for caching the pole drop data and the key phase voltage data and storing the trigger angle configuration value, a display device 26 for displaying information related to the trigger angle measurement and configuration process, and an input device 28 for receiving configuration information from the user. In some embodiments, the key phase voltage data can be provided on a separate digital data input.

[0050] In some embodiments, the machine monitoring system 10 may include cards other than the piston rod descent monitoring card 16, each card having circuitry for monitoring other aspects of the machine. In other embodiments, the machine monitoring system 10 may be a stand-alone device for monitoring piston rod descent, such as a portable handheld data collector or a permanently or temporarily mounted monitoring device.

[0051] Figure 3 and Figure 4 A preferred embodiment of process 100 is shown, which is used to determine an optimal trigger angle configuration value based on rod drop voltage data and key phase voltage data, such as using... Figure 2 The data collected by the exemplary system 10 shown. (Reference) Figure 3 After the compressor has been confirmed to be operating at a constant speed (step 102), system 10 begins the process of configuring monitoring card 16 with predetermined values ​​that will be used to monitor rod descent (step 104). As previously discussed, one of these predetermined values ​​is the trigger angle. In a preferred embodiment, the user clicks a button on display 26 to initiate the trigger angle measurement routine (step 106), at which point the processor 22 of monitoring card 16 begins analyzing the rod descent voltage signal data to automatically calculate the trigger angle (step 108). This analysis is detailed in [link to analysis]. Figure 4 .

[0052] refer to Figure 4The processor 22 of monitoring card 16 continuously monitors the rod drop voltage and key phase voltage (step 120). Based on the key phase voltage, the complete rotation of the flywheel is indicated by two consecutive detections of the keyway (steps 122 to 128). An exemplary curve of the rod drop voltage amplitude relative to the rotation angle of the flywheel through a 2 1 / 2 rotation is shown in the figure. Figure 5 In the middle. A large and overall sinusoidal signal with a period of approximately 360 degrees is a normalized bar drop voltage. Figure 5 Other signals are the slope (mathematical derivative) of the voltage signal falling on the rod, as calculated by processor 22. Figure 4 Step 130). Processor 22 analyzes the slope signal to find the time range within one rotation, where most consecutive values ​​of the slope signal are within a predetermined amplitude range about zero (step 132). The start and end times of the time range seen in step 132 are saved (step 134), and the midpoint time within that time range is calculated (step 136). Based on the timing of two consecutive keyway detections (steps 124 to 128) and the known rotational speed of the flywheel, processor 22 calculates the rotation angle associated with the midpoint time (step 138). The known piston angle value is then added to the rotation angle value calculated in step 138 to determine the trigger angle (step 140). This trigger angle value is in Figure 3 Return at step 110.

[0053] Refer again Figure 3 The calculated trigger angle value is displayed on the display device 26, and the user is given the option to accept the calculated value for configuration purposes or to utilize a previously stored configuration value of the trigger angle (step 112). If the user selects to use the calculated value, the trigger angle configuration value is set to the calculated value (step 114), and the configuration value is sent to the memory 24 of the monitoring card 16 (step 116). Using the calculated trigger angle configuration value, the monitoring card 16 then monitors and analyzes the lever descent signal (step 118). If the user selects not to use the calculated value, the monitoring card 16 monitors and analyzes the lever descent signal using a previously stored trigger angle configuration value.

[0054] In some embodiments, Figure 3 and Figure 4 The process shown and described herein can be automatically executed by the monitoring card 16 periodically or on a schedule to recalculate the trigger angle and update the trigger angle configuration value. This eliminates the need for periodic manual reconfiguration.

[0055] The preferred embodiments of the invention have been presented for purposes of illustration and description. These descriptions are not intended to be exhaustive or to limit the invention to the precise forms disclosed. In view of the foregoing teachings, obvious modifications or variations are possible. The embodiments have been chosen and described to provide the best illustration of the principles of the invention and its practical application, and to enable those skilled in the art to utilize the invention in various embodiments and to utilize various modifications suitable for the particular purpose contemplated. All such modifications and variations are within the scope of the invention as defined by the appended claims when interpreted according to the breadth to which they are fairly, legally, and justly enjoyed.

Claims

1. A machine monitoring system for acquiring information about machine operation, the machine having a piston rod and a rotating component, the piston rod being connected to the rotating component, the system comprising: A lever position sensor is mounted adjacent to the piston rod, and the lever position sensor generates a lever position voltage signal during operation of the machine, the lever position voltage signal indicating the degree of proximity of the piston rod relative to the lever position sensor; and A pole position monitor circuit communicating with the pole position sensor, the pole position monitor circuit comprising: One or more analog-to-digital converters, the one or more analog-to-digital converters being used to sample the pole position voltage signal and to convert the pole position voltage signal into digital pole position data; and A processor operable to execute operation instructions for processing the digital pole position data, the operation instructions including instructions that, when executed: —Determine the rotational speed of the rotating component of the machine; —Detect the complete rotation of the rotating component of the machine; —Based on the digital rod position data, a plurality of slope values ​​of the rod position voltage signal are determined, wherein the slope values ​​are calculated sample by sample during the complete rotation of the rotating component, and each slope value indicates the slope of the rod position voltage signal between adjacent data samples; —Find, within the plurality of slope values, a slope value that is continuous in time and whose amplitude is within a predetermined amplitude range about zero slope; —Determine the time range during the complete rotation of the rotating component that has the maximum number of slope values ​​that are continuous in time and whose amplitudes are within the predetermined amplitude range with respect to zero slope; —Determine the rotation angle of the rotating component corresponding to the time range; and The trigger angle is calculated based on the rotation angle according to the following formula: Trigger angle = Rotation angle + Piston angle, where the piston angle is a predetermined stored value; and A memory for storing trigger angle configuration values, the trigger angle configuration values ​​corresponding to the trigger angle calculated by the processor.

2. The machine monitoring system of claim 1, wherein the processor determines the midpoint of the time range and determines the rotation angle corresponding to the midpoint.

3. The machine monitoring system according to claim 2, wherein the slope value within the time range includes a starting slope value and an ending slope value, wherein the starting slope value corresponds to a starting angle or a starting time, wherein the ending slope value corresponds to an ending angle or an ending time, and wherein the rotation angle determined by the processor corresponds to the midpoint angle between the starting angle and the ending angle, or corresponds to the midpoint time between the starting time and the ending time.

4. The machine monitoring system of claim 1, wherein after calculating the trigger angle, the processor continuously monitors the rod descent of the piston rod in trigger mode based on the rod position voltage determined by the calculated trigger angle.

5. The machine monitoring system according to claim 1, further comprising: A display device is used to display the calculated trigger angle for user observation; and Input device, the input device being used to receive input from the user for selection: —The trigger angle configuration value corresponding to the trigger angle calculated by the processor; or —The predetermined trigger angle configuration value stored in the memory.

6. The machine monitoring system of claim 1, wherein the rod position sensor includes a proximity transducer mounted adjacent to the piston rod.

7. The machine monitoring system according to claim 1 further includes a key phase sensor installed near the rotating component, the key phase sensor generating a key phase voltage signal having pulses corresponding to the rotation of the rotating component.

8. A method for obtaining information about machine operation, the machine having a piston rod and a rotating component, the piston rod being connected to the rotating component, the method comprising: (a) A rod position voltage signal is generated using a rod position sensor mounted adjacent to the piston rod, wherein the rod position voltage signal indicates the degree of proximity of the piston rod relative to the rod position sensor during operation of the machine; (b) Sample the pole position voltage signal and convert the pole position voltage signal into digital pole position data; (c) Determine the rotational speed of the rotating component of the machine; (d) Detecting the complete rotation of the rotating component of the machine; (e) Determine multiple slope values ​​of the rod position voltage signal based on the digital rod position data, wherein the slope values ​​are calculated sample by sample during the complete rotation of the rotating component, and each slope value indicates the slope of the rod position voltage signal between adjacent data samples; (f) Among the plurality of slope values, find the slope value that is continuous in time and whose amplitude is within a predetermined amplitude range about zero slope; (g) Determine the time range during the complete rotation of the rotating component that has the maximum number of slope values ​​that are continuous in time and whose amplitudes are within the predetermined amplitude range with respect to zero slope; (h) Determine the rotation angle of the rotating component corresponding to the time range determined in step (g); (i) Calculate the trigger angle based on the rotation angle according to the following formula: trigger angle = rotation angle + piston angle, wherein the piston angle is a predetermined stored value; as well as (j) The trigger angle configuration value is stored in a memory device, wherein the trigger angle configuration value corresponds to the trigger angle calculated in step (i).

9. The method of claim 8, wherein step (h) includes determining the midpoint of the time range determined in step (g), and determining the rotation angle corresponding to the midpoint.

10. The method of claim 9, wherein the slope value within the time range includes a starting slope value and an ending slope value, wherein the starting slope value corresponds to a starting angle or a starting time, wherein the ending slope value corresponds to an ending angle or an ending time, and wherein the rotation angle corresponds to the midpoint angle between the starting angle and the ending angle, or corresponds to the midpoint time between the starting time and the ending time.

11. The method of claim 8, further comprising continuously monitoring the rod descent of the piston rod in trigger mode based on the rod position voltage determined at the trigger angle calculated in step (i).

12. The method of claim 8, further comprising displaying the trigger angle calculated in step (i) for user observation, and receiving input from the user to select: —The trigger angle configuration value corresponding to the trigger angle calculated in step (i); or —A predetermined trigger angle configuration value stored in the memory device.

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