A device for detecting and alarming oil supply for lathe worktable

Abstract

The utility model discloses a kind of oil supply detection alarm devices for lathe workstation, it is related to lathe lubrication monitoring technical field, including perception layer, processing layer, execution layer, communication and AI layer;In filter element blockage or pipeline leakage early stage, flow attenuation signal appears before pressure drop;The utility model uses turbine / electromagnetic flowmeter can identify abnormality before pressure has not dropped significantly, 30-120s earlier than traditional pressure monitoring average, and the incidence of injury accident is reduced by more than 90%;Processing layer is built-in three-stage alarm module and realizes " deceleration-pause-quick stop" progressive protection;Communication and AI layer is built-in based on Python AI prediction maintenance module, and LSTM time series analysis is carried out to flow, pressure, temperature historical data, and filter element remaining life and oil deterioration trend are predicted 1-2 weeks in advance, and "replace as needed" is realized;The use of the utility model upgrades "postmortem shutdown" to "pre-classified intervention", and the reliability, machining accuracy and economic benefit of large lathe are significantly improved.

Description

Technical Field

[0001] This utility model relates to the field of lathe lubrication monitoring technology, specifically to an oil supply detection and alarm device for a lathe worktable. Background Technology

[0002] The worktable-guideway pair of large lathes must continuously receive a stable and clean lubricating oil film under high-speed and heavy-load conditions. Insufficient lubrication will cause "abrasion" on the guideway surface—metal micro-melting, adhesion, and tearing. This can result in surface roughness deterioration or, in severe cases, guideway failure. Traditional monitoring methods have the following drawbacks:

[0003] 1. Limited monitoring dimensions: Generally, only mechanical pressure relays or pressure sensors are installed at the end of the main oil circuit or distributor. When the filter element is clogged, the pipeline leaks, or the pump volumetric efficiency decreases, the pressure drop lags behind the flow rate decay by 30–120 seconds, resulting in an alarm timing that is too late.

[0004] 2. Coarse threshold setting: The pressure relay only has two states, "pressure on / pressure off", and cannot distinguish fault modes such as "gradual filter blockage", "minor pipeline leaks", and "sudden temperature changes", resulting in a high false alarm and missed alarm rate.

[0005] 3. Crude linkage strategy: After the alarm is triggered, the machine tool is usually stopped immediately, causing unnecessary downtime and reducing the overall equipment efficiency.

[0006] 4. Lack of predictive maintenance: Lubricating oil and filter replacement are still performed according to fixed cycles, resulting in both "over-maintenance" and "exceeding service life", and annual lubrication-related costs remain high.

[0007] The aforementioned problems have long constrained the reliability and economy of high-end lathes. There is an urgent need in the market for a compact online device that can monitor multiple parameters such as flow rate, pressure and temperature in real time, provide graded alarms, intervene in advance, and have predictive maintenance functions. Utility Model Content

[0008] The purpose of this utility model is to provide an oil supply detection and alarm device for a lathe worktable, so as to solve the problems mentioned in the background art, such as the existing lathe worktable generally adopts pressure detection to monitor the lubrication oil circuit, and the pressure change lags behind the flow rate decay when the filter element is blocked or the pipeline leaks, which leads to the damage accident.

[0009] To achieve the above objectives, this utility model provides the following technical solution: a lathe worktable oil supply detection and alarm device, comprising a sensing layer, a processing layer, an execution layer, and a communication and AI layer connected in sequence; the sensing layer includes an oil supply pipeline for the lathe worktable and a flow meter and a pressure detector are installed thereon, the flow meter and pressure detector being electrically connected to the processing layer respectively; the processing layer includes digital instruments electrically connected to the flow meter and pressure detector respectively, the digital instruments being provided with a digital display screen and instrument buttons, and also electrically connected to a three-level alarm module, the three-level alarm module being electrically connected to an alarm light and the execution layer respectively; the execution layer includes a lathe control system interface... The three-level alarm signals issued by the three-level alarm module are all input to the machine tool control system through the lathe control system interface. The machine tool control system has built-in control software and outputs multi-level protection commands such as "deceleration, pause, and emergency stop" according to the corresponding first-level, second-level, and third-level alarm signals. The communication and AI layer includes a host computer, which has a built-in Python-based AI predictive maintenance module. The digital instrument has built-in RS-485 (Modbus-RTU) + CANopen dual protocol with a baud rate of 115.2kbps and an optional industrial Ethernet (Profinet, EtherNet / IP) gateway.

[0010] Preferably, the flow meter is a turbine flow meter or an electromagnetic flow meter, including a flow measuring tube with a diameter of φmm and a flow transmitter connected as an integral unit. A flow direction arrow is laser-etched on the outer wall of the flow measuring tube. The flow transmitter has a built-in dual Hall element and can detect the instantaneous flow rate in the range of 0.3-30L / min. The flow transmitter can output a 4-20mA analog signal to convert the flow value detected by the flow meter into an analog signal and electrically transmit it to the processing layer.

[0011] Preferably, the pressure detector includes a Φ6mm pressure tapping tube and a pressure sensor at its top. The pressure sensor is connected to a pressure transmitter, which can output a 4-20mA analog signal to convert the pressure value detected by the pressure detector into an analog signal and transmit it electrically to the processing layer.

[0012] Preferably, the front end of the pressure tapping tube is equipped with a 40μm sintered filter.

[0013] Preferably, a PT1000 platinum resistance thermometer is provided on the flow measurement tube and the pressure tapping tube respectively, and the PT1000 platinum resistance thermometer is connected to the flow transmitter and the pressure transmitter respectively.

[0014] Preferably, the digital instrument uses a 32-bit ARM Cortex-M7 as the main controller and is electrically connected to the digital display screen and the instrument buttons respectively; the refresh cycle of the digital instrument is 0.1s; the digital display screen uses a 3.5″ IPS full-view color LCD, which displays dual-channel real-time curves and values ​​on the same screen; it supports simultaneous display of flow, pressure and temperature on three axes.

[0015] Preferably, the three-level alarm module triggers a first-level yellow alarm and issues an alarm signal when it detects a continuous flow rate decrease rate > 5% / min or a pressure rise rate > 8% / min; the three-level alarm module triggers a second-level orange alarm and issues an alarm signal when it detects an instantaneous flow rate > 15% of the rated value and a pressure drop > 10%; and the three-level alarm module triggers a third-level red alarm and issues an alarm signal when it detects a flow pulse fluctuation amplitude < a set threshold and a pressure < 0.2MPa.

[0016] Preferably, the three-level alarm module has a built-in "signal integrity algorithm" to perform self-checks on open circuit, short circuit, and over-range of the flow meter and pressure detector sensors, and the fault code is displayed in the upper right corner of the digital display screen.

[0017] Preferably, the alarm light is a 72mm tower type with yellow, orange, and red LEDs and a brightness of 1200 cd / m². 2 The buzzer's sound pressure level at 1m is ≥85dB; it supports three adjustable levels: 90dB, 70dB, and silent; when the alarm light receives a level 1 yellow alarm signal, it will light up yellow and emit a buzzer; when the alarm light receives a level 2 orange alarm signal, it will light up orange and emit a buzzer; when the alarm light receives a level 3 red alarm signal, it will light up red and emit a buzzer.

[0018] Preferably, the lathe control system interface adopts a standard 24V PTP three-wire high-speed optocoupler isolation output, compatible with Fanuc, Siemens, and Mitsubishi PLCs; alarm signal mapping: and when the digital instrument loses power, the pressure detector can directly drive the machine tool's original pressure relay to ensure a minimum safe shutdown function.

[0019] Compared with the prior art, the beneficial effects of this utility model are:

[0020] 1. In the early stages of filter blockage or pipeline leakage, the flow rate attenuation signal appears before the pressure drop. This utility model uses a 0.3–30L / min full-range turbine / electromagnetic flow meter, combined with a high-speed 32-bit ARM Cortex-M7 digital instrument with a 0.1s refresh cycle, which can identify abnormalities before the pressure drops significantly, on average 30–120s earlier than traditional pressure monitoring, and reduces the incidence of scuffing accidents by more than 90%.

[0021] 2. The processing layer has a built-in three-level alarm module, which outputs yellow-orange-red signals based on composite criteria such as "flow rate decrease > 5% / min", "instantaneous flow > 15% of rated value and pressure drop > 10%", and "flow pulse amplitude < threshold and pressure < 0.2MPa". The execution layer seamlessly links with Fanuc / Siemens / Mitsubishi PLCs through a standard 24V PAP optical coupler interface to achieve progressive protection of "deceleration-pause-emergency stop".

[0022] 3. The communication and AI layer incorporates a Python-based AI predictive maintenance module. This module performs LSTM time-series analysis on historical flow, pressure, and temperature data to predict the remaining lifespan of the filter element and oil degradation trends 1-2 weeks in advance, enabling "on-demand replacement." Field practice shows that the annual filter element replacement frequency has decreased from a fixed 4 times to 2.3 times, lubricant consumption has decreased by 20%, and overall maintenance costs have decreased by 25-30%.

[0023] 4. Significant economic benefits: Taking an 8m CNC heavy-duty lathe as an example, after installing this utility model: the number of downtime maintenance due to guide rail damage is reduced by 4 times per year, with an average of 36 hours per downtime, directly saving about 300,000 yuan in labor and spare parts costs; the production capacity increase due to improved equipment efficiency is about 5%, which, based on an annual processing output value of 20 million yuan, results in an additional benefit of 1 million yuan; lubricating oil and filter element savings are 30,000 yuan per year; the comprehensive annual economic benefit is ≥1.3 million yuan, and the investment payback period is <3 months.

[0024] In summary, this utility model, through the organic combination of high-precision multi-parameter sensing, hierarchical intelligent alarm, PLC linkage control, and AI predictive maintenance, upgrades the traditional "post-event shutdown" to "pre-event hierarchical intervention," significantly improving the reliability, machining accuracy, and economic benefits of large lathes, and filling the gap in the domestic field of online intelligent monitoring of machine tool lubrication. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the connection structure of this utility model;

[0026] In the diagram: Sensing Layer-1, Oil Supply Line-101, Flow Meter-102, Pressure Detector-103, Flow Measurement Tube-104, Flow Transmitter-105, Flow Direction Arrow-106, Pressure Tap-107, Pressure Sensor-108, Pressure Transmitter-109, Sintered Filter-110, PT1000 Platinum Resistance Meter-111, Processing Layer-2, Digital Instrument-201, Digital Display Screen-202, Instrument Buttons-203, Three-Level Alarm Module-204, Alarm Light-205, Execution Layer-3, Lathe Control System Interface-301, Communication and AI Layer-4, Host Computer-401. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments.

[0028] This utility model provides a lubrication detection and alarm device for a lathe worktable, which integrates multi-level alarm, fault self-diagnosis, and AI predictive maintenance into a system; it includes a perception layer 1, a processing layer 2, an execution layer 3, and a communication and AI layer 4 connected in sequence.

[0029] The sensing layer includes an oil supply line 101 for the lathe worktable, and a flow meter 102 for real-time detection of the flow rate of the oil supply line and a pressure detector 103 for real-time detection of the pressure of the oil supply line are installed on the oil supply line 101; the flow meter 102 and the pressure detector 103 are electrically connected to the processing layer 2 respectively.

[0030] The flow meter 102 is a turbine flow meter or an electromagnetic flow meter, including a flow measuring tube 104 with a diameter of φ20mm and a flow transmitter 105 connected as an integral unit. A flow direction arrow 106 is laser-etched on the outer wall of the flow measuring tube 104 to prevent reverse installation. The flow transmitter 105 has a built-in dual Hall element and can detect instantaneous flow in the range of 0.3–30L / min. The flow transmitter 105 can output a 4-20mA analog signal to convert the flow value detected by the flow meter 102 into an analog signal and electrically transmit it to the processing layer 2.

[0031] The pressure detector 103 includes a Φ6mm pressure tapping tube 107. A pressure sensor 108 is provided at the top end of the pressure tapping tube 107. The pressure sensor 108 is connected to a pressure transmitter 109. The pressure transmitter 109 can output a 4-20mA analog signal to convert the pressure value detected by the pressure detector 103 into an analog signal and transmit it electrically to the processing layer 2. A 40μm sintered filter 110 is provided at the front end of the pressure tapping tube 107 to prevent oil stains from clogging it.

[0032] In addition, PT1000 platinum resistance thermometers 111 are respectively installed on the flow measurement tube 104 and the pressure tapping tube 107. The PT1000 platinum resistance thermometers 111 are connected to the flow transmitter 105 and the pressure transmitter 109 respectively, thereby realizing temperature drift compensation in the range of 0–80℃ of the measurement results.

[0033] The processing layer 2 includes a digital instrument 201 electrically connected to the flow meter 102 and the pressure detector 103, respectively, for receiving the 4-20mA analog signals output by the flow meter 102 and the pressure detector 103, and converting the corresponding 4-20mA signals into corresponding flow and pressure values; the digital instrument 201 is provided with a digital display screen 202 for displaying flow and pressure values ​​and an instrument button 203 for assisting in setting alarm thresholds, and is also electrically connected to a three-level alarm module 204, which is electrically connected to an alarm light 205 and the execution layer 3 respectively.

[0034] The digital instrument 201 uses a 32-bit ARM Cortex-M7 as its main controller and is electrically connected to the digital display screen 202 and the instrument buttons 203 respectively; the refresh cycle of the digital instrument 201 is 0.1s.

[0035] The digital display screen 202 adopts a 3.5″ IPS full-view color LCD, with dual-channel real-time curves and numerical values ​​displayed on the same screen; it supports simultaneous display of three axes: flow rate, pressure, and temperature.

[0036] When the three-level alarm module 204 detects a continuous decrease in flow rate > 5% / min or a pressure increase rate > 8% / min, it triggers a first-level yellow alarm and issues an alarm signal, simultaneously indicating that the filter element in the oil supply line is clogged; when the three-level alarm module 204 detects an instantaneous flow rate > 15% of the rated value and a pressure drop > 10%, it triggers a second-level orange alarm and issues an alarm signal, simultaneously indicating that the oil supply line is leaking; when the three-level alarm module 204 detects a flow pulse fluctuation amplitude < a set threshold and a pressure < 0.2MPa, it triggers a third-level red alarm and issues an alarm signal, simultaneously indicating that the pump in the oil supply line has failed.

[0037] The three-level alarm module 204 has a built-in "signal integrity algorithm" that performs self-checks on open circuit, short circuit, and over-range of the flow meter 102 and pressure detector 103 sensors, and displays the fault code in the upper right corner of the digital display screen 202.

[0038] The alarm light 205 is a 72mm tower type and features yellow, orange, and red LEDs with a brightness of 1200 cd / m². 2 The buzzer's sound pressure level at 1m is ≥85dB; it supports three adjustable levels: 90dB, 70dB, and silent; when the alarm light 205 receives a level 1 yellow alarm signal, it will light up yellow and emit a buzzer; when the alarm light 205 receives a level 2 orange alarm signal, it will light up orange and emit a buzzer; when the alarm light 205 receives a level 3 red alarm signal, it will light up red and emit a buzzer.

[0039] The execution layer 3 includes a lathe control system interface 301, which serves as an external interface for the machine tool control system. The three-level alarm signals issued by the three-level alarm module 204 are all input to the machine tool control system through the lathe control system interface 301. The machine tool control system has built-in control software and outputs multi-level protection commands such as "deceleration, pause, and emergency stop" according to the corresponding first-level, second-level, and third-level alarm signals. This triggers the spindle deceleration mode and reduces the spindle feed to 70%, or the pause feed mode pauses the spindle feed and prompts for oil replenishment, or the emergency stop mode immediately stops the machine and locks the spindle, thereby preventing lathe damage.

[0040] The lathe control system interface 301 adopts a standard 24VTP three-wire high-speed optocoupler isolation output, which is compatible with mainstream PLCs such as Fanuc, Siemens, and Mitsubishi; alarm signal mapping: and when the digital instrument 201 loses power, the pressure detector 103 can directly drive the machine tool's original pressure relay to ensure the minimum safe shutdown function.

[0041] The communication and AI layer 4 includes a host computer 401, which has a built-in Python-based AI predictive maintenance module. This module uses an LSTM network to train on multi-dimensional data of flow, pressure, temperature, and vibration to achieve: filter cartridge remaining life prediction error ≤ ±5%; dynamic threshold online refresh to avoid premature / late filter cartridge replacement; and annual spare parts cost savings of 20–30%. The digital instrument 201 has a built-in RS-485 (Modbus-RTU) + CANopen dual protocol with a baud rate of 115.2kbps. An optional industrial Ethernet (Profinet, EtherNet / IP) gateway is also available. The digital instrument 201 transmits the detection values ​​of the flow meter 102 and pressure detector 103 to the AI ​​predictive maintenance module in real time for judgment, displays the judgment results on the host computer, and pushes the judgment results to the corresponding APP through the industrial Ethernet (Profinet, EtherNet / IP) gateway to remind staff to handle the issue promptly.

[0042] The use of this invention can detect lubrication abnormalities 30-120 seconds in advance, transforming the traditional "post-event shutdown" into "pre-event graded intervention," significantly reducing the risk of workbench scratches, extending guide rail life, and reducing unplanned downtime.

[0043] Example:

[0044] A CNC vertical lathe has a rated flow rate of 6 L / min. The flow meter is installed 0.5 m from the main oil pump outlet, with straight pipe sections ≥10D before and after it. The flow meter is set to Q3 = 1.8 L / min. The pressure detector is installed at the inlet of the oil distributor. The digital instrument is embedded in the side wall of the machine tool, with an IP65 stainless steel housing. The alarm light is installed 1.8 m directly in front of the operator's line of sight. When the filter element becomes clogged and the flow rate drops to 1.8 L / min, the red light illuminates, and the lathe control system immediately stops the machine to prevent guide rail damage. In the event of a leak, the flow rate slowly decreases from 6 L / min to 3 L / min, triggering a self-diagnosis of a leak. The lathe control system pauses the feed and prompts for oil replenishment. Maintenance personnel complete the oil replenishment within 10 minutes, and the equipment resumes operation. Continuous monitoring over 6 months shows that the clogging alarm is triggered 35–110 seconds in advance, preventing 4 instances of guide rail damage. The leak alarm is triggered 20–60 seconds in advance, reducing lubricant consumption by 18%. The AI ​​model dynamically adjusts the filter element replacement cycle from a fixed 800 h to 650–950 h, increasing spare parts inventory turnover by 22%.

[0045] In addition, for lathes with a dual-pump main / standby system, a second-channel flow meter can be added to realize the main / standby pump switching logic; for the oil-air lubrication system, a micro differential pressure sensor can be connected in parallel to realize dual monitoring of "air path + oil path"; real-time data and alarm history can be remotely viewed via a mobile APP through Bluetooth / Wi-Fi module; an explosion-proof (ExdIIBT6) solution is available, which is suitable for cutting fluids containing flammable additives.

[0046] Although embodiments of the present invention have been shown and described, it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, it will be understood by those skilled in the art that all other embodiments obtained by making various changes, modifications, substitutions and alterations to these embodiments without departing from the principles and spirit of the present invention and without creative effort are within the scope of protection of the present invention.

Claims

1. A lubrication detection and alarm device for a lathe worktable, characterized in that: The system includes a perception layer (1), a processing layer (2), an execution layer (3), and a communication and AI layer (4) connected in sequence. The perception layer includes an oil supply line (101) for the lathe worktable, on which a flow meter (102) and a pressure detector (103) are installed. The flow meter (102) and the pressure detector (103) are electrically connected to the processing layer (2). The processing layer (2) includes a digital instrument (201) electrically connected to the flow meter (102) and the pressure detector (103), respectively. The digital instrument (201) is equipped with a digital display screen (202) and instrument buttons (203), and is also electrically connected to a three-level alarm module (204). The three-level alarm module (204) is electrically connected to an alarm light (205) and the execution layer (3). The execution layer (1) includes a perception layer (2), a processing layer (2), an execution layer (3), and a communication and AI layer (4). 3) Includes a lathe control system interface (301). The three-level alarm signals issued by the three-level alarm module (204) are all input to the machine tool control system through the lathe control system interface (301). The machine tool control system has built-in control software and outputs multi-level protection commands such as "deceleration, pause, and emergency stop" according to the corresponding first-level, second-level, and third-level alarm signals. The communication and AI layer (4) includes a host computer (401). The host computer (401) has a built-in AI prediction and maintenance module based on Python. The digital instrument (201) has built-in RS-485 (Modbus-RTU) + CANopen dual protocol with a baud rate of 115.2kbps and an optional industrial Ethernet (Profinet, EtherNet / IP) gateway.

2. The oil supply detection and alarm device for a lathe worktable according to claim 1, characterized in that: The flow meter (102) is a turbine flow meter or an electromagnetic flow meter, including a flow measuring tube (104) with a diameter of φ (20) mm and a flow transmitter (105) connected together. A flow direction arrow (106) is laser-etched on the outer wall of the flow measuring tube (104). The flow transmitter (105) has a built-in dual Hall element and can detect the instantaneous flow rate in the range of 0.3-30 L / min. The flow transmitter (105) can output a 4-20mA analog signal to convert the flow value detected by the flow meter (102) into an analog signal and electrically transmit it to the processing layer (2).

3. The oil supply detection and alarm device for a lathe worktable according to claim 2, characterized in that: The pressure detector (103) includes a Φ6mm pressure tapping tube (107) and a pressure sensor (108) at its top end. The pressure sensor (108) is connected to a pressure transmitter (109). The pressure transmitter (109) can output a 4-20mA analog signal to convert the pressure value detected by the pressure detector (103) into an analog signal and transmit it electrically to the processing layer (2).

4. The oil supply detection and alarm device for a lathe worktable according to claim 3, characterized in that: The pressure tapping tube (107) is equipped with a 40μm sintered filter (110) at its front end.

5. The oil supply detection and alarm device for a lathe worktable according to claim 4, characterized in that: The flow measurement tube (104) and the pressure tapping tube (107) are respectively equipped with PT1000 platinum resistance (111), and the PT1000 platinum resistance (111) is connected to the flow transmitter (105) and the pressure transmitter (109) respectively.

6. The oil supply detection and alarm device for a lathe worktable according to claim 5, characterized in that: The digital instrument (201) uses a 32-bit ARM Cortex-M7 as the main controller and is electrically connected to the digital display screen (202) and the instrument buttons (203) respectively; the refresh cycle of the digital instrument (201) is 0.1s; the digital display screen (202) uses a 3.5″ IPS full-view color LCD, with dual-channel real-time curves and numerical values ​​displayed on the same screen; it supports simultaneous display of flow, pressure and temperature on three axes.

7. The oil supply detection and alarm device for a lathe worktable according to claim 6, characterized in that: The three-level alarm module (204) triggers a first-level yellow alarm and issues an alarm signal when it detects a continuous flow rate decrease rate > 5% / min or a pressure rise rate > 8% / min; the three-level alarm module (204) triggers a second-level orange alarm and issues an alarm signal when it detects an instantaneous flow rate > 15% of the rated value and a pressure drop > 10%; the three-level alarm module (204) triggers a third-level red alarm and issues an alarm signal when it detects a flow pulse fluctuation amplitude < a set threshold and a pressure < 0.2MPa.

8. The oil supply detection and alarm device for a lathe worktable according to claim 7, characterized in that: The three-level alarm module (204) has a built-in "signal integrity algorithm" to perform self-tests on open circuit, short circuit, and over-range of the flow meter (102) and pressure detector (103) sensors, and the fault codes are displayed in the upper right corner of the digital display screen (202).

9. The oil supply detection and alarm device for a lathe worktable according to claim 8, characterized in that: The alarm light (205) is a 72mm tower type and has yellow, orange and red LEDs with a brightness of 1200cd / m². 2 The sound pressure level of the buzzer at 1m is ≥85dB; it supports three adjustable levels: 90dB / 70dB / silent; when the alarm light (205) receives a first-level yellow alarm signal, it will light up yellow and emit a buzzer; when the alarm light (205) receives a second-level orange alarm signal, it will light up orange and emit a buzzer; when the alarm light (205) receives a third-level red alarm signal, it will light up red and emit a buzzer.

10. The oil supply detection and alarm device for a lathe worktable according to claim 9, characterized in that: The lathe control system interface (301) adopts a standard 24VPNP three-wire high-speed optocoupler isolation output, which is compatible with Fanuc, Siemens, and Mitsubishi PLCs; alarm signal mapping: and when the digital instrument (201) is powered off, the pressure detector (103) can directly drive the machine tool's original pressure relay to ensure the minimum safe shutdown function.

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