Early warning method for maintenance period of base plate at mobile end of hydraulic press

Abstract

The invention provides an early warning method for a maintenance period of a base plate at a mobile end of a hydraulic press. Comprising the steps that 1, whether the thinning amount of a single base plate exceeds a threshold value or not is judged; 2, calculating the position height variation of bolt rods (9) on the two sides of the movable rack (3), and judging whether the position height variation exceeds a threshold value or not; 3, judging whether the single-side base plate is replaced or not; step 4, judging whether the single base plate on the side is replaced or both the two base plates are replaced; and 5, through four-step logic judgment of the system, accurate replacement early warning of 1-2 base plates (6) at the corresponding positions below the supporting wheels (5) of the movable rack (3) of the steel pipe hydraulic press is achieved. On the premise that the maximum use efficiency of the base plate can be guaranteed, early warning is triggered in advance, accurate replacement is guided, 1-2 base plates are specifically replaced, and the online and quantifiable logic judgment method for the replacement period of the base plate at the movable rack end of the steel pipe hydraulic press is achieved; and the utilization rate of the base plate material is improved to the greatest extent while early warning is performed.

Description

Technical Field

[0001] This invention belongs to the technical field of steel pipe hydrostatic testing machine; in particular, it relates to a method for early warning of maintenance cycle of the moving end pad of a hydrostatic testing machine. Background Technology

[0002] Large-diameter steel pipe hydraulic presses typically employ a four-tension beam arrangement, with both ends connected by pin cylinders mounted on a water-filling frame and a moving frame. During the steel pipe hydraulic pressing process, the moving frame end undergoes frequent reciprocating motion due to the need for pipe passage and water pressure sealing. Since the moving frame generally weighs 70-100 tons, prolonged reciprocating motion can cause the base plate at the bottom of the moving frame to thin or partially break. This problem leads to a decrease in the center height of the moving frame, causing the pins on the tension beams to become stuck in the through holes and unable to be pulled out, resulting in unplanned shutdowns and production stoppages, impacting the steel pipe plant's output and economic benefits.

[0003] To address the unplanned production stoppages caused by the drop in center height of the moving frame due to wear of the pads, which leads to stuck pins that cannot be removed, the common practice among domestic pipe manufacturers is as follows:

[0004] (1) Manual periodic inspection and visual inspection for defects. When a large scratch or dent is found manually, the machine is stopped immediately and the pad at that location is replaced. This method relies on manpower, requires long-term observation and inspection, and does not meet the safety production requirements in the work area, posing a high safety risk. At the same time, scratches or local damage do not mean that some pads cannot work properly, which may lead to material waste and increased downtime.

[0005] (2) Manual elevation marking. When the equipment is stopped, all pads on both sides are manually marked for elevation. If the elevation difference is too large, the pad is replaced. This method can reduce material waste while ensuring safety, but it is time-consuming and labor-intensive, usually requiring 6-8 hours, and is highly dependent on manual experience. In addition, a large elevation difference does not necessarily mean that some pads are not working properly, and there is a lack of a systematic method for judgment.

[0006] (3) Replacement after failure. After the pin cannot be easily pulled out, further processing and replacement of the washer are required. This usually takes 1-2 days. It severely impacts the pipe factory's steel pipe production.

[0007] While the above methods can ultimately replace the pads and resolve the issue of decreased center height of the mobile rack, the replacement of the pads is done after offline shutdown, requiring extensive manual observation and subjective judgment. This lacks a systematic, online early warning system and objective, quantifiable criteria, and it cannot maximize material utilization or improve maintenance intervals.

[0008] Based on the technical shortcomings of the existing technology, there is an urgent need to solve the technical problems of a method for early warning of maintenance cycle of the moving end pad of a hydraulic press. Summary of the Invention

[0009] The purpose of this invention is to provide a method for early warning of the maintenance cycle of the moving end pad of a hydraulic press.

[0010] This invention is achieved through the following technical solution:

[0011] This invention relates to a method for early warning of maintenance cycle of a moving end pad in a hydraulic press, comprising the following steps:

[0012] Step 1: By detecting and comparing the change in height difference between the laser rangefinder 4 and the four pads 6 corresponding to the support wheel 5, determine whether the thinning amount of a single pad exceeds the threshold.

[0013] Step 2: Calculate the change in height of the pins 9 on both sides of the mobile frame 3 and determine whether it exceeds the threshold.

[0014] Step 3: Calculate whether the difference in height of the pins 9 on the left and right sides of the mobile frame 3 exceeds the threshold, and determine whether to replace the single-sided pad.

[0015] Step 4: Calculate whether the difference in height change of the two pads 6 on one side of the mobile frame 3 exceeds the threshold, and determine whether to replace the single pad on that side or replace both pads.

[0016] Step 5: Through the system's four-step logical judgment, the system can accurately replace the 1-2 pads 6 at the corresponding positions below the support wheels 5 of the steel pipe hydraulic press mobile frame 3; no additional pads 6 need to be replaced, and the material utilization rate of the pads is maximized.

[0017] Preferably, the method specifically includes:

[0018] The relative height between the position of the laser rangefinder 4 on the mobile frame 3 and the position of the upper surface of the pad 6 that contacts the four support wheels 5 on the mobile frame 3 is monitored in real time by the laser rangefinder 4. The initial height is set to H, and the difference in the initial height H of the four points does not exceed ±0.2mm.

[0019] The absolute values ​​of the differences between the actual height and the initial height at the four points are named ΔH1, ΔH2, ΔH3, and ΔH4, respectively.

[0020] Among them, ΔH1 and ΔH2 are on the same side of the moving frame, and the change in height of the pin cylinder 2 at the midpoint between the two points is named ΔHF; ΔHF=1 / 2(ΔH1+ΔH2)

[0021] ΔH3 and ΔH4 are on the same side of the moving frame. The change in height of the pin cylinder 2 at the midpoint between the two points is named ΔHE; ΔHE = 1 / 2(ΔH3 + ΔH4).

[0022] The gap between the mounting hole 9 and the through hole 8 of the tension beam is named δ.

[0023] Preferably, the specific steps of the method are as follows:

[0024] (1) Read the values ​​of ΔH1, ΔH2, ΔH3, and ΔH4;

[0025] (2) Determine whether ΔHi < 0.9δ. If yes, continue to use. If no, alarm and wait for the process gap to stop and replace the corresponding pad at a certain point of ΔHi. i = 1, 2, 3, 4; where ΔHi is the difference between the height of the laser range sensor 4 to the upper surface of the pad 6 and the initial height.

[0026] (3) Calculate the values ​​of ΔHF and ΔHE;

[0027] (4) Determine whether ΔHF is ≤0.8δ. If yes, continue to use it. If no, set an alarm and wait for the process interval to stop. Replace the two pads 6 corresponding to ΔH1 and ΔH2.

[0028] (5) Determine whether ΔHE is ≤0.8δ. If yes, continue to use it. If no, set an alarm and wait for the process interval to stop. Replace the two pads 6 corresponding to ΔH3 and ΔH4.

[0029] (6) Based on ΔHF≤0.8δ and ΔHE≤0.8δ, determine whether |ΔHE-ΔHF|≥0.3δ; if not, continue using it;

[0030] (7) Determine the difference between ΔHE and ΔHF. If it is >0, continue to determine whether |ΔH3-ΔH4| is ≥0.5δ. If not, trigger an alarm and wait for the process interval to stop. Replace the two pads corresponding to ΔH3 and ΔH4. If yes, continue to determine whether ΔH3-ΔH4 is >0. If yes, replace pad 6 at ΔH3. If not, replace pad 6 at ΔH4.

[0031] Determine if ΔHE-ΔHF > 0. If not, continue to determine if |ΔH1-ΔH2| ≥ 0.5δ. If not, trigger an alarm and wait for the process interval to stop. Replace the two pads corresponding to ΔH3 and ΔH4. If yes, continue to determine if ΔH1-ΔH2 > 0. If yes, replace pad 6 at ΔH1. If no, replace pad 6 at ΔH2.

[0032] The present invention has the following advantages:

[0033] (1) This invention addresses the problem that existing visual or manual elevation methods cannot detect the wear status of pads in real time and quantitatively, and achieves millimeter-level dynamic monitoring of wear, avoiding over-reliance on experience, lack of standards, or post-event discovery; at the same time, it only provides early warning for pads that need to be replaced.

[0034] (2) This invention establishes an early warning method for the maintenance cycle of the pads on the mobile end of a hydraulic press. Under the premise of ensuring the maximum utilization efficiency of the pads, it triggers an early warning in advance and guides precise replacement, and replaces 1-2 pads in a targeted manner, transforming the sudden downtime of 1-2 days into planned 30-minute maintenance. This realizes an online and quantifiable logical judgment method for the replacement cycle of the pads on the mobile frame end of the steel pipe hydraulic press. While providing early warning, it maximizes the utilization rate of pad materials.

[0035] (3) This invention uses quantifiable standards to make online logical judgments, eliminating the need for tasks such as stopping the machine to mark height and visual inspection when entering dangerous areas, thus saving manpower costs and forming an online, quantifiable logical judgment method that saves manpower costs.

[0036] (4) This invention only requires replacing the pads that have reached the end of their service life, avoiding excessive maintenance such as replacing them whenever there are scratches. Only the pads at precise locations are replaced after logical judgment, without replacing all of them. This invention determines to replace 1-2 pads at designated locations through logical judgment, even if the remaining pads have scratches or local damage points, thus maximizing the service life of the pads.

[0037] (5) This invention enables early warning replacement, and maintenance can be integrated into the existing production process gap, eliminating 1-2 days of unplanned downtime and turning "sudden shutdown repair" into "planned maintenance".

[0038] (6) This invention completely eliminates secondary faults such as pin deformation, beam hole damage, and severe wear of side guide wheels caused by center sinking, saving additional machining and tension beam replacement costs, and completely eradicating the associated losses of "pin jamming". Attached Figure Description

[0039] Figure 1 This is a logic diagram for determining the maintenance cycle early warning method of the moving end pad of the hydraulic press according to the present invention;

[0040] Figure 2 This is a diagram showing the assembly relationship between the pin and the through hole of the tension beam;

[0041] Figure 3 This is a schematic diagram illustrating the determination principle of the early warning method for the maintenance cycle of the moving end pad of the hydraulic press according to the present invention;

[0042] Figure 4 This is a schematic diagram of the moving frame of the steel pipe hydrostatic testing machine tilting to the side;

[0043] Figure 5 This is a schematic diagram of the moving frame structure of the steel pipe hydrostatic testing machine;

[0044] Figure 6 This is a side view of the moving frame of the steel pipe hydrostatic testing machine;

[0045] Figure 7 This is the front view of the moving frame of the steel pipe hydrostatic testing machine.

[0046] Figure 8 This is a top view of the moving frame of the steel pipe hydrostatic testing machine;

[0047] Attached diagram labels: 1-Side guide wheel; 2-Pin cylinder; 3-Moving frame; 4-Laser rangefinder sensor; 5-Support wheel; 6-Pad; 7-Tension beam; 8-Tension beam through hole; 9-Pin rod. Detailed Implementation

[0048] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are merely further illustrations of the present invention, but the scope of protection of the present invention is not limited to the following embodiments.

[0049] Example 1

[0050] This embodiment relates to a method for early warning of the maintenance cycle of the moving end pad of a hydraulic press. See Figure 1 and Figure 3 As shown, it includes the following steps:

[0051] Step 1: By detecting and comparing the changes in the height difference between the laser rangefinder 4 and the four pads 6 corresponding to the support wheel 5, it is determined whether the thinning amount of a single pad exceeds the threshold; The structural diagram of the moving frame of the steel pipe hydrostatic testing machine is shown below. Figures 4-8 As shown;

[0052] Step 2: Calculate the change in height of the pins 9 on both sides of the mobile frame 3 and determine whether it exceeds the threshold.

[0053] Step 3: Calculate whether the difference in height of the pins 9 on the left and right sides of the mobile frame 3 exceeds the threshold, and determine whether to replace the single-sided pad.

[0054] Step 4: Calculate whether the difference in height change of the two pads 6 on one side of the mobile frame 3 exceeds the threshold, and determine whether to replace the single pad on that side or replace both pads.

[0055] Step 5: Through the system's four-step logical judgment, the system can accurately replace the 1-2 pads 6 at the corresponding positions below the support wheels 5 of the steel pipe hydraulic press mobile frame 3; no additional pads 6 need to be replaced, and the material utilization rate of the pads is maximized.

[0056] The specific judgment method of this method is as follows:

[0057] The relative height between the position of the laser rangefinder 4 on the mobile frame 3 and the position of the upper surface of the pad 6 that contacts the four support wheels 5 on the mobile frame 3 is monitored in real time by the laser rangefinder 4. The initial height is set to H, and the difference in the initial height H of the four points does not exceed ±0.2mm.

[0058] The absolute values ​​of the differences between the actual height and the initial height at the four points are named ΔH1, ΔH2, ΔH3, and ΔH4, respectively.

[0059] Among them, ΔH1 and ΔH2 are on the same side of the moving frame, and the change in height of the pin cylinder 2 at the midpoint between the two points is named ΔHF; ΔHF=1 / 2(ΔH1+ΔH2)

[0060] ΔH3 and ΔH4 are on the same side of the moving frame. The change in height of the pin cylinder 2 at the midpoint between the two points is named ΔHE; ΔHE = 1 / 2(ΔH3 + ΔH4).

[0061] The assembly hole clearance between the pin 9 and the through hole 8 of the tension beam is named δ. Figure 2 As shown.

[0062] Furthermore, the specific steps of the method are as follows:

[0063] (1) Read the values ​​of ΔH1, ΔH2, ΔH3, and ΔH4;

[0064] (2) Determine whether ΔHi < 0.9δ. If yes, continue to use. If no, alarm and wait for the process gap to stop and replace the corresponding pad at a certain point of ΔHi. i = 1, 2, 3, 4; where ΔHi is the difference between the height of the laser range sensor 4 to the upper surface of the pad 6 and the initial height.

[0065] (3) Calculate the values ​​of ΔHF and ΔHE;

[0066] (4) Determine whether ΔHF is ≤0.8δ. If yes, continue to use it. If no, set an alarm and wait for the process interval to stop. Replace the two pads 6 corresponding to ΔH1 and ΔH2.

[0067] (5) Determine whether ΔHE is ≤0.8δ. If yes, continue to use it. If no, set an alarm and wait for the process interval to stop. Replace the two pads 6 corresponding to ΔH3 and ΔH4.

[0068] (6) Based on ΔHF≤0.8δ and ΔHE≤0.8δ, determine whether |ΔHE-ΔHF|≥0.3δ; if not, continue using it;

[0069] (7) Determine the difference between ΔHE and ΔHF. If it is >0, continue to determine whether |ΔH3-ΔH4| is ≥0.5δ. If not, trigger an alarm and wait for the process interval to stop. Replace the two pads corresponding to ΔH3 and ΔH4. If yes, continue to determine whether ΔH3-ΔH4 is >0. If yes, replace pad 6 at ΔH3. If not, replace pad 6 at ΔH4.

[0070] Determine if ΔHE-ΔHF > 0. If not, continue to determine if |ΔH1-ΔH2| ≥ 0.5δ. If not, trigger an alarm and wait for the process interval to stop. Replace the two pads corresponding to ΔH3 and ΔH4. If yes, continue to determine if ΔH1-ΔH2 > 0. If yes, replace pad 6 at ΔH1. If no, replace pad 6 at ΔH2.

[0071] The symbols used in this invention have the following meanings:

[0072] H - The original height of the laser rangefinder 4 to the upper surface of the pad 6; ΔHi - The difference between the height of the laser rangefinder 4 to the upper surface of the pad 6 and the initial height; ΔHF - The average value of ΔH1 and ΔH2 at the midpoint (position of pin cylinder 2); ΔHE - The average value of ΔH3 and ΔH4 at the midpoint (position of pin cylinder 2); ΔS1 - The gap between the moving frame 3 and the tension beam 7 on the side of the side guide wheel 1; ΔS2 - The gap between the moving frame 3 and the tension beam 7 on the side without the side guide wheel 1.

[0073] Example 2

[0074] Specific implementation of the present invention:

[0075] (1) According to the method involved in Example 1, the following parameters are taken: when δ is 1 mm, ΔH1 = 0.9 mm; ΔH2 = 0.8 mm; ΔH3 = 0.5 mm; ΔH4 = 0.5 mm;

[0076] Based on calculations, since ΔH1 ≥ 0.9δ, the conclusion is: replace the pad corresponding to ΔH1 when the alarm is triggered.

[0077] (2) According to the method involved in Example 1, the following parameters are taken: when δ is 1 mm, ΔH1 = 0.8 mm; ΔH2 = 0.2 mm; ΔH3 = 0.4 mm; ΔH4 = 0.6 mm;

[0078] Calculations show that ΔHF = 0.5mm and ΔHE = 0.5mm. Although ΔH1, H2, H3, and H4 all show some wear, the change in a single pad is less than 0.9δ. Furthermore, since the changes on both sides at the pin cylinder position are the same and within the threshold values ​​(ΔHF ≤ 0.8δ, ΔHE ≤ 0.8δ, ΔHF = ΔHE), the moving frame can still operate normally. Based on the judgment, the situation indicates that all four pads have thinned to some extent, but the machine can still continue to operate.

[0079] (3) According to the method involved in Example 1, the following parameters are taken: when δ is 1 mm, ΔH1 = 0 mm; ΔH2 = 0.8 mm; ΔH3 = 0.5 mm; ΔH4 = 0.8 mm;

[0080] Calculations show that ΔHF = 0.4mm and ΔHE = 0.65mm, both less than 0.8δ, and |ΔHE - ΔHF| ≤ 0.3δ, so no alarm signal will be triggered. Although ΔH2 = 0.8mm and ΔH4 = 0.8mm, meaning the changes in two pads are close to 0.9δ, the changes at the pin cylinder positions on both sides are within the threshold values: ΔHF ≤ 0.8δ, ΔHE ≤ 0.8δ, and |ΔHE - ΔHF| ≤ 0.3δ. Therefore, even if two pads drop by 0.8mm, the moving frame can still operate normally. This method maximizes the utilization rate of the pads.

[0081] (4) According to the method involved in Example 1, the following parameters are taken: when δ is 1 mm, ΔH1 = 0.8 mm; ΔH2 = 0.3 mm; ΔH3 = 0.2 mm; ΔH4 = 0.2 mm;

[0082] Calculations show that ΔHF = 0.55 mm and ΔHE = 0.2 mm. Since |ΔHE - ΔHF| = 0.35 ≥ 0.3δ and ΔHE - ΔHF < 0, although the moving frame has tilted and the wear on the ΔHF side has reached a point requiring replacement, further analysis shows that |ΔH1 - ΔH2| ≥ 0.5δ and ΔH1 - ΔH2 > 0. Therefore, only the pad at ΔH1 needs replacement; the wear on ΔH2 is only 0.3 mm and does not require replacement.

[0083] This invention establishes a method for early warning of the maintenance cycle of the pads on the mobile end of a hydraulic press. Under the premise of ensuring the maximum utilization efficiency of the pads, it triggers an early warning in advance and guides precise replacement, replacing 1-2 pads in a targeted manner. This transforms a sudden downtime of 1-2 days into a planned 30-minute maintenance cycle, realizing an online and quantifiable logical determination method for the replacement cycle of the pads on the mobile frame end of a steel pipe hydraulic press. While providing early warning, it maximizes the utilization rate of pad materials.

[0084] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for early warning of maintenance cycle of a moving end pad of a hydraulic press, characterized in that, Includes the following steps: Step 1: By detecting and comparing the change in height difference between the laser rangefinder (4) and the upper surface of the four pads (6) corresponding to the support wheel (5), determine whether the thinning amount of a single pad exceeds the threshold. Step 2: Calculate the change in height of the pins (9) on both sides of the moving frame (3) and determine whether it exceeds the threshold. Step 3: Calculate whether the difference in height of the pins (9) on the left and right sides of the mobile frame (3) exceeds the threshold, and determine whether to replace the single-sided pad. Step 4: Calculate whether the difference in height change between the two pads (6) on one side of the mobile frame (3) exceeds the threshold, and determine whether to replace the single pad on that side or replace both pads. Step 5: Through the four-step logic judgment of the system, the system can accurately replace the 1-2 pads (6) at the corresponding positions below the support wheels (5) of the moving frame (3) of the steel pipe hydraulic press.

2. The method for early warning of maintenance cycle of the moving end pad of the hydraulic press as described in claim 1, characterized in that, The method is as follows: By using a laser rangefinder (4) installed on the mobile frame (3), the relative height between the position of the mobile frame sensor and the upper surface of the pad (6) that contacts the four support wheels (5) on the mobile frame (3) is monitored in real time. The initial height is set to H, and the difference in the initial height H of the four points does not exceed ±0.2mm. The absolute values ​​of the differences between the actual height and the initial height at the four points are named ΔH1, ΔH2, ΔH3, and ΔH4, respectively. Among them, ΔH1 and ΔH2 are on the same side of the moving frame, and the height change of the pin cylinder (2) at the midpoint between the two points is named ΔHF; ΔHF=1 / 2(ΔH1+ΔH2) ΔH3 and ΔH4 are on the same side of the moving frame. The change in height of the pin cylinder (2) at the midpoint between the two points is named ΔHE; ΔHE = 1 / 2(ΔH3 + ΔH4). The gap between the mounting hole of the pin rod (9) and the through hole (8) of the tension beam is named δ.

3. The method for early warning of maintenance cycle of the moving end pad of the hydraulic press as described in claim 2, characterized in that, The specific steps of the method are as follows: (1) Read the values ​​of ΔH1, ΔH2, ΔH3, and ΔH4; (2) Determine whether ΔHi < 0.9δ. If yes, continue to use. If no, alarm and wait for the process gap to stop and replace the corresponding pad (6) at a certain point of ΔHi. i = 1, 2, 3, 4; ΔHi - the difference between the height of the laser range sensor (4) to the upper surface of the pad (6) and the initial height. (3) Calculate the values ​​of ΔHF and ΔHE; (4) Determine whether ΔHF is ≤0.8δ. If yes, continue to use it. If no, alarm and wait for the process gap to stop. Replace the two pads corresponding to ΔH1 and ΔH2 (6). (5) Determine whether ΔHE is ≤0.8δ. If yes, continue to use it. If no, alarm and wait for the process gap to stop. Replace the two pads corresponding to ΔH3 and ΔH4 (6). (6) Based on ΔHF≤0.8δ and ΔHE≤0.8δ, determine whether |ΔHE-ΔHF|≥0.3δ; if not, continue using it; (7) Determine the difference between ΔHE and ΔHF. If it is >0, continue to determine whether |ΔH3-ΔH4| is ≥0.5δ. If not, trigger an alarm and wait for the process interval to stop. Replace the two pads corresponding to ΔH3 and ΔH4 (6). If yes, continue to determine whether ΔH3-ΔH4 is >0. If yes, replace the pad at ΔH3. If not, replace the pad at ΔH4 (6). Determine whether ΔHE-ΔHF > 0. If not, continue to determine whether |ΔH1-ΔH2| ≥ 0.5δ. If not, trigger an alarm and wait for the process interval to stop. Replace the two pads corresponding to ΔH3 and ΔH4 (6). If yes, continue to determine whether ΔH1-ΔH2 > 0. If yes, replace the pad at ΔH1 (6). If no, replace the pad at ΔH2 (6).

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