Ignition point pre-judgment method for preventing medical waste fire

Abstract

The invention discloses an ignition point pre-judgment method for preventing a medical waste fire in the technical field of medical waste pretreatment, various mechanical forces are applied to various batteries in a medical instrument, only one mechanical force is applied in single detection, and each battery is detected only once; performing voltage monitoring, temperature monitoring and / or visual image monitoring on the batteries subjected to mechanical safety detection so as to judge mechanical force conditions of thermal runaway of various batteries; evaluating the mechanical force applied to the battery in each pretreatment link, and comparing the mechanical force with the mechanical force condition of thermal runaway of each battery to obtain the probability of thermal runaway of each battery in each pretreatment link; according to the method, the types of the medical instruments to be treated are determined, the types of batteries possibly existing in the medical waste are preliminarily judged, then the probability of thermal runaway of the medical waste of the batch in all pretreatment links is obtained, key fire prevention deployment and control are conducted on the links with the high thermal runaway probability, the fire extinguishing response speed is increased, and a fire point is put out in time and rapidly.

Description

Technical Field

[0001] The present invention relates to the technical field of medical waste pretreatment, and particularly relates to a method for predicting the ignition point to prevent medical waste fires. Background Art

[0002] Common fields of medical batteries involve various medical devices such as automated external defibrillators, ventilators, continuous glucose monitors, capsule endoscopes, brain pacemakers, ultra-thin focusable nerve stimulators, and micro-implantable batteries. The common battery types for medical devices mainly include lithium batteries, lithium-ion batteries, No. 7 alkaline batteries, nickel-metal hydride batteries, lead-acid batteries, etc. Among them, lithium (ion) batteries and No. 7 alkaline batteries are representative.

[0003] During the pretreatment process of medical waste, in order to avoid personnel infection, the staff will not open the yellow medical waste transfer box to confirm the classification status of the medical waste inside. Therefore, medical waste may accidentally contain materials such as unremoved batteries from medical devices.

[0004] The battery may be affected by various mechanical forces in crushers, subsequent conveyor belts, garbage pits or the tail compartments of transfer vehicles, and there is a possibility of catching fire or exploding. After a fire breaks out, it is necessary to extinguish the medical waste fire and find the fire source. Due to numerous pretreatment links for medical waste and limited human and equipment resources, in the case of unable to predict the ignition point, the fire extinguishing response time is long, and it is impossible to quickly extinguish the ignition point in a timely manner. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for predicting the ignition point to prevent medical waste fires, so as to solve the technical problem in the prior art that due to numerous pretreatment links for medical waste and limited human and equipment resources, in the case of unable to predict the ignition point, the fire extinguishing response time is long, and it is impossible to quickly extinguish the ignition point in a timely manner.

[0006] To solve the above technical problem, the present invention specifically provides a method for predicting the ignition point to prevent medical waste fires, including the following steps:

[0007] Mechanical safety detection: Apply various mechanical forces to various batteries in medical devices respectively, and only apply one mechanical force in a single detection, and each battery is only detected once;

[0008] Data acquisition and monitoring: Monitor the voltage, temperature, and / or visual image of the batteries undergoing mechanical safety detection to determine the mechanical force conditions for various batteries to undergo thermal runaway;

[0009] Judge the probability of various batteries undergoing thermal runaway in each pretreatment link: Evaluate the mechanical forces that each pretreatment link will exert on the batteries, and compare them with the mechanical force conditions for various batteries to undergo thermal runaway to obtain the probability of various batteries undergoing thermal runaway in each pretreatment link;

[0010] Judge the probability of medical waste catching fire in each pre-treatment link: confirm the types of medical devices to be processed, preliminarily judge the types of batteries that may exist in the medical waste, and then obtain the probability of thermal runaway of the medical waste in each pre-treatment link, and conduct key fire prevention control on the links with high thermal runaway probability.

[0011] As a preferred embodiment of the present invention, the mechanical safety detection includes extrusion test, tensile test, heavy object impact test, vibration test and free fall test, and each type of battery is subjected to at least three or more of the same type of tests.

[0012] As a preferred embodiment of the present invention, if the battery meets any one of the following three conditions in the mechanical safety detection, it is determined that the battery has thermal runaway:

[0013] The triggering object generates a voltage drop, and the drop value exceeds 25% of the initial voltage;

[0014] The temperature at the monitoring point reaches the maximum operating temperature specified by the manufacturer or above 52°C at room temperature;

[0015] Phenomena such as shell rupture, liquid leakage, overheating or local high temperature, smoking, fire, explosion, etc. appear in the visual image and last for more than 3s.

[0016] As a preferred embodiment of the present invention, a multimeter, the original circuit or an additional newly added test circuit is used to monitor the voltage. The sampling interval of the voltage data should be less than 1s, and the accuracy requirement is ±0.5%. The positive and negative electrodes of the battery are connected to the multimeter;

[0017] An infrared thermal imager or a temperature sensor is used to monitor the temperature. The sampling interval of the temperature data should be less than 1s, and the accuracy requirement is ±2°C;

[0018] A camera or a camera is used to monitor the visual image. The sampling interval of the visual image data should be less than 1s.

[0019] As a preferred embodiment of the present invention, record the time from when the battery withstands a single mechanical force to the determination of thermal runaway or alarm, and the state of the battery within 10 minutes after the thermal runaway of the battery is triggered. If the single battery or battery pack does not experience overheating or local high temperature, smoking, fire, or explosion, it is considered that the ignition source of the medical waste passes the mechanical safety detection.

[0020] The present invention has the following beneficial effects compared with the prior art:

[0021] The present invention conducts mechanical safety tests on various batteries in medical devices, and monitors through data acquisition the mechanical force conditions under which various batteries undergo thermal runaway. By comparing these with the mechanical forces applied in each pretreatment step, the probabilities of various batteries undergoing thermal runaway in each pretreatment step are obtained. Based on the types of batteries that may be present in the medical waste to be processed, the probabilities of thermal runaway of this batch of medical waste in each pretreatment step are determined, and key fire prevention measures are taken for the steps with high thermal runaway probabilities to improve the fire extinguishing response speed and promptly extinguish the ignition points. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are merely exemplary, and those of ordinary skill in the art can also obtain other implementation drawings based on the provided drawings without creative efforts.

[0023] Figure 1 It is a flowchart of the ignition point prediction method in the present invention;

[0024] Figure 2 It is a voltage monitoring result / change curve of a lithium battery after heavy object impact in the present invention;

[0025] Figure 3 It is a temperature monitoring result / change curve of a lithium battery after heavy object impact in the present invention;

[0026] Figure 4 It is a temperature distribution map monitored by an infrared thermal imager when the battery in the present invention undergoes thermal runaway. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0028] The present invention specifically provides an ignition point prediction method for preventing medical waste fires, including the following steps:

[0029] Mechanical safety test: Apply various mechanical forces to various batteries in medical devices respectively, and only apply one mechanical force in a single test, and each battery is only tested once;

[0030] Data acquisition and monitoring: Monitor the voltage, temperature, and / or visual image of the battery undergoing mechanical safety testing to determine the mechanical force conditions for thermal runaway of various batteries.

[0031] Judge the probability of thermal runaway of various batteries in each pre-treatment link: Evaluate the mechanical force exerted on the battery in each pre-treatment link and compare it with the mechanical force conditions for thermal runaway of various batteries to obtain the probability of thermal runaway of various batteries in each pre-treatment link.

[0032] Judge the probability of ignition of each batch of medical waste in each pre-treatment link: Confirm the types of medical devices to be processed, preliminarily judge the types of batteries that may be present in the medical waste, and then obtain the probability of thermal runaway of this batch of medical waste in each pre-treatment link, and conduct key fire prevention control on the links with high thermal runaway probability.

[0033] It should be noted that medical device waste generally has a fixed source. Therefore, although the staff will not conduct an unpacking inspection on the medical waste transfer box, they can still clearly know whether there are medical devices in this batch of waste to be processed, and can know the types of medical devices in the transfer box according to the processing documents. They just cannot confirm whether the battery has been removed, but they can also know the corresponding battery types according to the types of medical devices, and then know the possible battery types in the transfer box.

[0034] The mechanical safety testing should be carried out in the following environment:

[0035] Temperature: Room temperature (-53~52°C), Atmospheric pressure: Room pressure (57.11 kPa~101.76 kPa).

[0036] The accuracy of the measuring instruments and equipment should not be lower than the following regulations: Voltage measuring device: ±0.5%; Temperature measuring device: ±2°C; Time measuring device: ±1 s; Dimension measuring device: ±1 mm; Mass measuring device: ±0.5%.

[0037] During the mechanical safety testing, only one type of mechanical force should be simulated each time. The failures directly caused by the mechanical safety testing process (such as direct damage to the material) are considered part of the failure conditions.

[0038] The present invention conducts mechanical safety inspections on various batteries in medical devices, and obtains the mechanical force conditions for thermal runaway of various batteries through data acquisition and monitoring. By comparing with the mechanical forces applied in each pre-treatment link, the probability of thermal runaway of various batteries in each pre-treatment link is obtained. According to the types of batteries that may exist in the medical waste to be processed, the probability of thermal runaway of this batch of medical waste in each pre-treatment link is determined, and key fire prevention measures are taken for the links with a high probability of thermal runaway to improve the fire extinguishing response speed and promptly extinguish the ignition point.

[0039] Further, when setting a single mechanical force, the reasonable and foreseeable mechanical force should be determined by checking the pre-treatment process of medical waste. For example, extrusion, stretching, heavy object impact, vibration, and free fall of medical waste, etc.

[0040] To ensure the reliability of the test results, each type of battery should be subjected to at least three or more of the same tests, that is, each type of battery is respectively subjected to extrusion, stretching, heavy object impact, vibration, and free fall tests three times each, and new batteries are used each time, and the same battery is not subjected to a second test.

[0041] The specific test method is as follows:

[0042] Extrusion test:

[0043] Place the single battery or battery pack with the rated capacity in the middle between two steel plates on the upper and lower sides. The size of the extrusion plate is larger than the size of the single battery to be extruded, but does not exceed 1000 mm.

[0044] The extrusion direction is the vertical ground direction, and each single battery or battery pack only undergoes 1 extrusion.

[0045] The extrusion speed is (5 ± 1) mm / s. When the battery pack is extruded to 70% of its original size, or when the extrusion force reaches 13 kN, it is maintained for 1 min, and then the extrusion force is removed and observed for 1 h.

[0046] Tensile test:

[0047] Fix the single battery or battery pack with the rated capacity in the middle of the test equipment with a rigid test fixture. The size of the tensile fixture is larger than the size of the single battery to be stretched, but does not exceed 1000 mm.

[0048] The tensile direction is the vertical ground direction, and each single battery or battery pack only undergoes 1 tensile.

[0049] The tensile speed is 5 mm / min. During the tensile process, the surface packaging film of the battery tears off and the test ends.

[0050] Heavy object impact test:

[0051] Place a single cell or battery pack with rated capacity directly on the test equipment tabletop or fix it with the help of a rigid test object. The size of the impact weight is larger than that of the single cell to be impacted, but does not exceed 1000 mm.

[0052] The direction of the weight impact is vertically downward towards the ground. Each single cell or battery pack only undergoes 1 impact.

[0053] Use a weight with a mass of 9.1 kg ± 0.1 kg to freely fall from a height of 60 - 150 cm ± 5 mm and impact the surface of the battery with a metal bar placed on it. After the test, let it stand still and observe for 30 min.

[0054] Vibration test:

[0055] Install a single cell or battery pack with rated capacity directly on the test equipment tabletop or with the help of a rigid test fixture, and conduct random vibration tests according to the specified vibration spectrum. Vibration is carried out in vertical and horizontal directions for 40 min - 60 min. After the test, let it stand still and observe for 10 min. Each single cell or battery pack only undergoes 1 set or single - cycle vibration.

[0056] Free - fall test:

[0057] Let a single cell or battery pack with rated capacity freely fall from a height (the lowest point height of the battery pack) of 1000 - 3000 mm onto a concrete plane. Free - fall is carried out in vertical and horizontal directions. After the test, let it stand still and observe for 10 min. Each single cell or battery pack only undergoes 1 free - fall.

[0058] The specific monitoring methods involved in the present invention are as follows:

[0059] Use a multimeter, the original circuit, or an additional newly added test circuit to monitor the voltage. The sampling interval of voltage data should be less than 1 s, and the accuracy requirement is ±0.5%. Connect the positive and negative electrodes of the battery to the multimeter;

[0060] Use an infrared thermal imager or a temperature sensor to monitor the temperature. The sampling interval of temperature data should be less than 1 s, and the accuracy requirement is ±2°C;

[0061] Use a camera or a camera to monitor the visual image. The sampling interval of visual image data should be less than 1 s.

[0062] It can be understood that during the data acquisition and monitoring process, in addition to monitoring voltage, temperature, and visual images, auxiliary judgment can also be carried out by detecting size and mass.

[0063] Use a calibrated scale, camera, or camera to detect the size. The sampling interval of size data should be less than 1 s, and the accuracy requirement is ±1 mm.

[0064] For the inspection of quality, calibrated measuring instruments such as balances shall be used. The accuracy requirement for quality data is ±0.5%.

[0065] It can be understood that when conducting mechanical safety inspections and data acquisition monitoring, time monitoring is required. A stopwatch, camera, or infrared thermal imager shall be used for time monitoring. The sampling interval of time data shall be less than 1 s, and the accuracy requirement is ±1 s.

[0066] The standard for the battery to pass the mechanical safety inspection is as follows:

[0067] Record the time from when the battery withstands a single mechanical force until thermal runaway is determined or an alarm is triggered, and the state of the battery within 10 minutes after thermal runaway of the battery is triggered. If the single cell or battery pack does not experience overheating, local high temperature, smoking, fire, or explosion, it is considered that the ignition source of the medical waste passes the mechanical safety inspection.

[0068] If any one of the following three conditions occurs during the mechanical safety inspection of the battery, it is determined that the battery has experienced thermal runaway:

[0069] The triggering object generates a voltage drop, and the drop value exceeds 25% of the initial voltage;

[0070] The temperature at the monitoring point reaches the maximum operating temperature specified by the manufacturer or above room temperature of 52°C;

[0071] Phenomena such as shell rupture, liquid leakage, overheating, local high temperature, smoking, fire, or explosion appear in the visual image and persist for more than 3 s.

[0072] The above embodiments are only exemplary embodiments of the present application and are not used to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements within the essence and protection scope of the present application, and such modifications or equivalent replacements should also be regarded as falling within the protection scope of the present application.

Claims

1. A method for predicting the ignition point for preventing medical waste fires, characterized in that: The following steps are involved: Mechanical safety testing: Multiple mechanical forces are applied to various batteries in medical devices, and only one mechanical force is applied in a single test, and each battery is tested only once; Data acquisition monitoring: voltage monitoring, temperature monitoring and / or visual image monitoring of batteries undergoing mechanical safety testing to determine the mechanical force conditions that may cause thermal runaway in various batteries; Determine the probability of thermal runaway of various batteries in various pretreatment links: Evaluate the mechanical force applied to the battery in each pretreatment link, and compare it with the mechanical force conditions for thermal runaway of various batteries to obtain the probability of thermal runaway of various batteries in each pretreatment link; Determine the probability of each batch of medical waste catching fire in each pre-treatment link: confirm the type of medical device to be processed, preliminarily determine the type of battery that may be present in the medical waste, and then obtain the probability of thermal runaway in each pre-treatment link of the batch of medical waste, and focus on fire prevention and control in the links with high probability of thermal runaway to improve the fire extinguishing response speed and extinguish the fire point in a timely and rapid manner.

2. A method for predicting the ignition point for preventing medical waste fires according to claim 1, characterized in that: The mechanical safety test includes extrusion test, tensile test, heavy object impact test, vibration test and free fall test, and each battery is subjected to at least three tests of the same type.

3. The method for predicting the ignition point for preventing medical waste fire according to claim 1, characterized in that: If any of the following three conditions occur during the mechanical safety test of the battery, the battery is considered to be in thermal runaway: The trigger object generates a voltage drop, and the drop value exceeds 25% of the initial voltage; The temperature at the monitoring point reaches the maximum operating temperature specified by the manufacturer or the room temperature is above 52°C; The visual image shows shell rupture, leakage, overheating or local high temperature, smoke, fire, explosion and other phenomena, which last for more than 3 seconds.

4. The method for predicting the ignition point for preventing medical waste fire according to claim 1, characterized in that: The voltage is monitored using a multimeter, the original circuit, or an additional test circuit. The sampling interval of the voltage data should be less than 1s, and the accuracy requirement is ±0.5%. The positive and negative poles of the battery are connected to the multimeter; The temperature is monitored using an infrared thermal imager or temperature sensor. The sampling interval of the temperature data should be less than 1s, and the accuracy requirement is ±2°C. Visual images should be monitored using a video camera or still camera, and the sampling interval of visual image data should be less than 1s.

5. The method for predicting the ignition point for preventing medical waste fires according to claim 1, characterized in that: The time from when the battery is subjected to a single mechanical force to when thermal runaway is determined or an alarm is given, as well as the battery status within 10 minutes after the thermal runaway is triggered, is recorded. If the single cell or battery pack does not overheat or experience local high temperature, smoke, fire, or explosion, the medical waste ignition source is considered to have passed the mechanical safety test.

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