A device for real-time monitoring of extinguishing agent levels in CO2 fire extinguishers and a CO2 fire extinguisher.

Abstract

This invention discloses a device for real-time monitoring of the extinguishing agent level in a CO2 fire extinguisher. The device comprises a vertical tube disposed within the fire extinguisher canister, with its top fixed to the top of the fire extinguisher. The vertical tube contains a first corrugated metal diaphragm box and a second corrugated metal diaphragm box spaced vertically apart, rigidly connected by a hard core. A transmission rod is fixed to the top of the first corrugated metal diaphragm box, extending upwards from the fire extinguisher canister and remaining sealed to the canister wall. A connecting port at the upper part of the vertical tube connects the gas phase space within the fire extinguisher canister with the space from the first corrugated metal diaphragm box to the top of the vertical tube. An external display component shows the remaining CO2 level based on the displacement distance of the transmission rod. This invention also discloses a CO2 fire extinguisher equipped with this detection device. This invention can display the remaining liquid CO2 level in real time, facilitating inspection.

Description

Technical Field

[0001] This invention relates to a device for detecting the amount of extinguishing agent in a fire extinguisher and to a fire extinguisher in general, belonging to the field of liquid level detection technology. Background Technology

[0002] To ensure CO2 fire extinguishers achieve their intended extinguishing effect during a fire, regular inspection and maintenance are crucial. However, because CO2 extinguishing agent is stored in a pressurized liquefied form, the presence of both liquid and gas within the extinguisher makes routine inspections via pressure monitoring difficult. Determining the liquid level through pressure requires measuring both the CO2 gas phase pressure and the liquid pressure separately to calculate the liquid level. Since the CO2 gas phase pressure changes with varying liquid levels, it's impossible to visually observe changes in liquid level simply by observing pressure variations. Routine inspections of CO2 fire extinguishers typically employ a weighing comparison method every six months, but this method cannot accurately determine the actual extinguishing agent level. The lack of clarity regarding the actual liquid level during CO2 fire extinguisher use could potentially lead to secondary accidents during the extinguishing process.

[0003] Existing technologies for monitoring the level of pressurized liquefied gas commonly include float level gauges, radar level gauges, ultrasonic level gauges, and capacitive level gauges. These are mainly used in large storage tanks or tank trucks, covering liquid oxygen, liquid nitrogen, and liquefied petroleum gas. These detection methods all rely on electricity and the equipment is relatively large, making them unsuitable for routine monitoring of fire extinguishers. Integrating relevant sensing elements into fire extinguishers would require significant modifications to the existing fire extinguisher structure. Furthermore, adding independent battery power and electronic components to fire extinguishers would raise explosion-proof safety concerns at fire scenes. Summary of the Invention

[0004] To address the aforementioned shortcomings of the existing technology, the present invention aims to provide a device for real-time monitoring of the extinguishing agent level in CO2 fire extinguishers. This solves the problem that pressure gauges are insufficient to accurately determine the extinguishing agent level, while conventional level gauges require energized operation, posing a safety hazard. The present invention also aims to provide a CO2 fire extinguisher that displays the remaining liquid CO2 level in real time for convenient inspection.

[0005] The technical solution of this invention is as follows: A device for real-time monitoring of the extinguishing agent level in a CO2 fire extinguisher includes a vertical tube disposed inside the fire extinguisher canister. The top of the vertical tube is fixed to the top of the fire extinguisher. A first corrugated metal diaphragm box and a second corrugated metal diaphragm box are disposed vertically and spaced apart. The first and second corrugated metal diaphragm boxes are rigidly connected by a hard core. A transmission rod is fixed to the top surface of the first corrugated metal diaphragm box. The transmission rod extends upward from the fire extinguisher canister and remains sealed to the canister wall. A communication port is provided at the upper part of the vertical tube to connect the gas phase space inside the fire extinguisher canister with the space from the first corrugated metal diaphragm box to the top of the vertical tube. A display component is provided outside the fire extinguisher canister to display the extinguishing agent level based on the displacement distance of the transmission rod.

[0006] Furthermore, the vertical tube body is filled with rigid insulating oil between the first corrugated metal diaphragm box and the second corrugated metal diaphragm box.

[0007] Furthermore, the rigid insulating oil is an oil with a density higher than that of liquefied carbon dioxide.

[0008] Furthermore, the second corrugated metal diaphragm box is disposed at the bottom end of the vertical tube, and the distance between the bottom end of the vertical tube and the bottom of the fire extinguisher canister is no greater than 1 / 10 of the rated height of the liquefied carbon dioxide in the fire extinguisher canister.

[0009] Furthermore, a shock-absorbing spring is connected between the top surface of the first corrugated metal diaphragm box and the vertical tube.

[0010] Furthermore, the display component includes a gear transmission assembly, a pointer, and a dial. The top of the transmission rod is provided with a rack, and the gear transmission assembly meshes with the rack and drives the pointer to rotate on the dial.

[0011] Furthermore, the vertical tube is a metal circular tube.

[0012] Furthermore, the display component includes a vertical indicator, and the top of the transmission rod is provided with an indicator arrow. When the transmission rod moves, it drives the indicator arrow to indicate different positions of the vertical indicator.

[0013] Furthermore, the vertical indicator can be raised and lowered outside the fire extinguisher tank.

[0014] Another technical solution of the present invention is a CO2 fire extinguisher, comprising a fire extinguisher canister, wherein the fire extinguisher canister is provided with a nozzle and the aforementioned device for real-time monitoring of the extinguishing agent level of the CO2 fire extinguisher, and the fire extinguisher canister is filled with liquid CO2.

[0015] The advantages of this invention compared to the prior art are:

[0016] This invention utilizes a vertical tube to introduce gaseous CO2. The pressure difference between the liquid CO2 and the structure inside the vertical tube drives the displacement of the transmission rod, which in turn indicates the remaining liquid CO2 level via a display component. By using pressure difference to drive the level detection, interference from gas leakage or changes in gaseous CO2 pressure after use is naturally eliminated, resulting in high accuracy.

[0017] This invention does not rely on a power source, possesses high reliability, and is suitable for routine inspection and maintenance of fire extinguishers. Because it does not use electronic components or batteries, there is no need to consider explosion-proof measures. Fire management personnel or firefighters can monitor the status of carbon dioxide fire extinguishers in real time without the need for additional equipment, thus promptly determining whether the fire extinguisher is in an effective state.

[0018] This invention features a compact structure that has minimal impact on the original structure of fire extinguishers, and it also has a low cost advantage, making it easy to promote and apply on a large scale. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a CO2 fire extinguisher with a device for real-time monitoring of the extinguishing agent level.

[0020] Figure 2 This is a partial schematic diagram of the location of the first corrugated metal diaphragm box.

[0021] Figure 3 This is a partial schematic diagram of the location of the second corrugated metal diaphragm box.

[0022] Figure 4 This is a schematic diagram of the display component structure according to another specific embodiment. Detailed Implementation

[0023] The present invention will be further described below with reference to embodiments, but these are not intended to limit the scope of the invention.

[0024] Please combine Figures 1 to 3 As shown, the CO2 fire extinguisher includes a fire extinguisher canister 1, which is filled with liquid CO2. The fire extinguisher canister 1 is equipped with a nozzle 2 to spray the vaporized CO2. To facilitate fire management personnel or firefighters in checking the liquid CO2, a device for real-time monitoring of the CO2 extinguishing agent level is also installed on the fire extinguisher canister 1.

[0025] The device for real-time monitoring of the extinguishing agent level in a CO2 fire extinguisher in this embodiment mainly includes a vertical tube 3, a first corrugated metal diaphragm box 4, a second corrugated metal diaphragm box 5, a rigid core 6, a transmission rod 7, and a display component.

[0026] The vertical tube 3 is a pressure-resistant metal circular tube, vertically installed inside the fire extinguisher container 1. Given the high pressure inside the CO2 fire extinguisher, the pressure-bearing capacity of the vertical tube 3 must exceed the rated filling pressure of the CO2 fire extinguisher. The top of the vertical tube 3 is fixed to the top of the fire extinguisher. The length of the vertical tube 3 is chosen to be approximately equal to the height of the fire extinguisher container 1, ensuring that the bottom end of the vertical tube 3 is close to the bottom of the fire extinguisher container 1 while maintaining continuity between the bottom ends of the vertical tube 3 and the bottom of the fire extinguisher container 1. It is acceptable that the distance between the bottom end of the vertical tube 3 and the bottom of the fire extinguisher container 1 is no more than 1 / 10 of the rated height of the liquefied carbon dioxide inside the fire extinguisher container 1.

[0027] The first corrugated metal diaphragm box 4 and the second corrugated metal diaphragm box 5 are fixedly installed in the vertical tube 3 at an interval. To reduce detection errors, the second corrugated metal diaphragm box 5 is installed at the bottom end of the vertical tube 3. The first corrugated metal diaphragm box 4 and the second corrugated metal diaphragm box 5 serve two purposes: isolating the liquid CO2 phase and converting the pressure difference into displacement. A rigid core 6 is rigidly connected between the bottom surface of the first corrugated metal diaphragm box 4 and the top surface of the second corrugated metal diaphragm box 5, and the rigid core 6 transmits the pressure on the first corrugated metal diaphragm box 4 and the second corrugated metal diaphragm box 5.

[0028] A connecting port 3a is provided at the upper part of the vertical tube 3 to connect the gas phase space inside the fire extinguisher canister 1 with the space from the first corrugated metal diaphragm box 4 to the top of the vertical tube 3. That is, the connecting port 3a is located higher than the first corrugated metal diaphragm box 4. According to this structure, the deformation of the first corrugated metal diaphragm box 4 and the second corrugated metal diaphragm box 5 will be affected by the pressure generated by the liquid CO2 and the gravity of the rigid core 6. In a preferred embodiment, since the pressure generated by the liquid CO2 is relatively large, balancing the pressure generated by the liquid CO2 through the gravity of the rigid core 6 may require the rigid core 6 to be designed to be thicker, thus requiring the vertical tube 3 to be thicker. Therefore, rigid insulating oil 8 is filled inside the vertical tube 3 between the first corrugated metal diaphragm box 4 and the second corrugated metal diaphragm box 5. By using the rigid insulating oil 8 and the pressure generated by the rigid core 6 on the second corrugated metal diaphragm box 5 to balance the pressure generated by the liquid CO2, a more compact volume can be achieved. The rigid insulating oil 8 is an oil with a density higher than liquefied carbon dioxide, and can generally be silicone oil, fluorinated oil, glycerin, etc.

[0029] The transmission rod 7 is fixedly installed on the top surface of the first corrugated metal diaphragm box 4 and extends upward from the fire extinguisher canister 1. A shaft seal 9 is provided between the transmission rod 7 and the canister wall of the fire extinguisher canister 1 to maintain a seal. The pressure resistance of the shaft seal 9 must be greater than the rated filling pressure of the fire extinguisher. A shock-absorbing spring 10 is connected between the top surface of the first corrugated metal diaphragm box 4 and the vertical tube 3. During the filling process of the extinguishing agent, the internal pressure of the fire extinguisher will change. By using the shock-absorbing spring 10, it can be ensured that the corrugated metal diaphragm box will not be damaged due to drastic pressure changes. In a specific embodiment, the display component includes a gear transmission assembly 12, a pointer 13, and a dial 14. The top of the transmission rod 7 is machined into a rack 11. The gear transmission assembly 12 meshes with the rack 11 and drives the pointer 13 to rotate when the transmission rod 7 is displaced, thereby indicating the remaining amount of liquid CO2 by the position of the pointer 13 on the dial 14.

[0030] Please combine Figure 4 As shown, in some specific embodiments, the display component can be an indicator 15 erected on one side of the transmission rod 7. The indicator 15 can be installed outside the fire extinguisher canister 1 in a height-adjustable manner, and its specific adjustment method is not limited to adjustment with screws and guide rods 16. An indicator arrow 17 is provided on the transmission rod 7, and the position of the indicator arrow 17 on the indicator 15 is changed by the displacement of the transmission rod 7 to indicate the remaining amount of liquid CO2.

[0031] The principle of the device for real-time monitoring of the extinguishing agent level in a CO2 fire extinguisher is as follows: After gaseous CO2 enters the vertical tube 3 through the connecting port 3a, it exerts pressure on the first corrugated metal diaphragm box 4. This pressure is transmitted to the second corrugated metal diaphragm box 5 via the rigid core 6. The rigid core 6 is made of a lightweight, rigid material. Ignoring the weight of the rigid core 6 and the transmission rod 7, the pressure on the top surface of the second corrugated metal diaphragm box 5 is mainly generated by the gaseous CO2 and the rigid insulating oil 8. The pressure on the bottom surface of the second corrugated metal diaphragm box 5 is mainly generated by the gaseous CO2 and the liquid CO2. When the bottom of the vertical tube 3 is positioned as close as possible to the bottom of the fire extinguisher tank 1, ignoring the distance between the metal tube and the bottom of the fire extinguisher and the gas density difference, according to the principle of statics, we can obtain:

[0032] P u,0 =P g +ρ t ·g·H d (1)

[0033] P d,0 =P g +ρ l ·g·H l (2) Among them, P u,0 P is the pressure on the top surface of the second corrugated metal diaphragm box 5. d,0 The pressure ρ is the pressure on the top surface of the second corrugated metal diaphragm box 5. t and ρl These are the densities of insulating oil 8 and liquid CO2, respectively, H d and H l These represent the heights of insulating oil (8) and liquid CO2, respectively. After the fire extinguisher is filled, the pressure on both sides of the second corrugated metal diaphragm box (5) reaches equilibrium, i.e., P... u,0 =P d,0 Then, combining equations (1) and (2), we have

[0034]

[0035] According to formula (3), the height of the rigid insulating oil 8 that needs to be filled in the vertical tube 3 can be calculated. This height is affected by the type of insulating oil 8. When the density is higher than that of liquefied carbon dioxide, the liquid level of the insulating oil 8 will be lower than the liquid CO2 height after the fire extinguisher is filled. In fact, it is quite difficult to accurately obtain the liquid height data after filling for a specific carbon dioxide fire extinguisher. In addition, the liquid height will also fluctuate due to factors such as ambient temperature. Therefore, the height of the insulating oil 8 filled in this invention may be higher or lower than the result calculated by formula (3). At this time, after the liquid CO2 is filled to the rated capacity, the height of the indicator 15 in the display component can be adjusted so that the indicator arrow 17 corresponds to the reference position of the indicator 15, such as "1".

[0036] When there is a leak of carbon dioxide extinguishing agent in the fire extinguisher or after use, the carbon dioxide liquid level drops by ΔH. l At this time, the corresponding height of the carbon dioxide liquid is . Combining equations (1) and (2), the pressure difference ΔP across the corrugated metal diaphragm box at this time is . f It can be represented as:

[0037] ΔP f =P u -P d =ρ t ·g·H d -ρ l ·g·H′ l ′ (4)

[0038] Further transformation of formula (4) yields:

[0039] ΔP f =ρ t ·g·H d -ρ l ·g·H l +ρ l ·g·ΔH l (5)

[0040] Substituting formula (3) into formula (5), we get:

[0041] ΔP f=ρ l ·g·ΔH l (6)

[0042] The second corrugated metal diaphragm box 5 generates a pressure difference ΔP on both sides. f The corresponding metal diaphragm cell will generate a displacement x. These two are linearly related, as detailed below:

[0043] ΔP f =K·x (7) Where K represents the elastic modulus of the second corrugated metal diaphragm 5, which is a constant value. According to the analysis of equation (6), it can be seen that the pressure on the upper side of the second corrugated metal diaphragm 5 is greater than that on the lower side, so the first corrugated metal diaphragm 4 and the second corrugated metal diaphragm 5 move downwards. The transmission rod 7 is rigidly connected to the first corrugated metal diaphragm 4. When the first corrugated metal diaphragm 4 moves downwards, the transmission rod 7 also moves downwards. Then the liquid level change of liquid CO2 is displayed through the display component. From equations (6) and (7), it can be obtained that

[0044]

[0045] According to equation (8), the liquid level of CO2 is highly correlated with the displacement of the transmission rod 7. After modification, equation (8) can be further expressed as:

[0046]

[0047] in, This indicates the filling ratio of the extinguishing agent. When the extinguishing agent reaches its rated filling capacity, the filling ratio is 1. If the value on dial 14 is 1, it means the liquid level has reached the rated filling capacity. For CO2 fire extinguishers, the annual leakage rate is specified not to exceed 5% of the rated filling capacity. If the value on dial 14 is less than 0.95, it means the liquid level is low and the fire extinguisher needs to be replenished with CO2 extinguishing agent promptly.

[0048] Taking a 5kg portable carbon dioxide fire extinguisher as an example, the extinguisher has a diameter of 15cm, a height of 52.5cm, and a rated filling pressure of 25.2MPa. The liquid phase density of the extinguishing agent is approximately 960kg / m³. 3 Ignoring the mass of the gas phase, the liquid height can be roughly estimated at 29.47 cm based on the extinguisher diameter and liquid density. The insulating oil used is fluorinated oil with a density of 2000 kg / m³. 3 The theoretical design height of insulating oil 8 is approximately 14.2 cm, calculated using formula (3).

[0049] A leak was simulated by manually spraying a carbon dioxide fire extinguisher. The amount of extinguishing agent sprayed (i.e., the leakage amount) was determined by weighing, and the current extinguishing agent filling ratio was calculated. The measurement results were compared with the values ​​on dial 14 to verify the reliability of the invention; specific data are shown in Table 1.

[0050] Table 1 Comparison of readings and measurement results of the invention device for propellant filling ratio.

[0051]

[0052] Observations show that the reading error is smaller when the extinguishing agent filling ratio is higher. This indicates that the present invention has high accuracy. Although the reading error is larger when the leakage is higher, the device of the present invention meets the requirements from the perspective of daily inspection and monitoring of fire extinguishers. This is because when the filling ratio is lower than 0.95, it means that the carbon dioxide fire extinguisher cannot achieve the fire extinguishing effect and needs to be refilled with extinguishing agent.

Claims

1. A device for real-time monitoring of the extinguishing agent level in a CO2 fire extinguisher, characterized in that, The device includes a vertical tube installed inside the fire extinguisher canister. The top of the vertical tube is fixed to the top of the fire extinguisher. The vertical tube contains a first corrugated metal diaphragm box and a second corrugated metal diaphragm box spaced vertically apart. The second corrugated metal diaphragm box is located at the bottom end of the vertical tube. The distance between the bottom end of the vertical tube and the bottom of the fire extinguisher canister is no greater than 1 / 10 of the rated height of the liquefied carbon dioxide inside the canister. The first and second corrugated metal diaphragm boxes are rigidly connected by a hard core. A transmission device is fixed to the top of the first corrugated metal diaphragm box. The fire extinguisher has a drive rod extending upwards from the fire extinguisher canister, which is sealed to the canister wall. A connecting port at the top of the vertical tube allows communication between the gas phase space inside the fire extinguisher canister and the space from the first corrugated metal diaphragm box to the top of the vertical tube. An external display unit shows the remaining energy level based on the displacement distance of the drive rod. Rigid insulating oil, with a density higher than liquefied carbon dioxide, is filled between the first and second corrugated metal diaphragms inside the vertical tube.

2. The device for real-time monitoring of extinguishing agent levels in CO2 fire extinguishers according to claim 1, characterized in that, A shock-absorbing spring is connected between the top surface of the first corrugated metal diaphragm box and the vertical tube.

3. The device for real-time monitoring of extinguishing agent levels in CO2 fire extinguishers according to claim 1, characterized in that, The display component includes a gear transmission assembly, a pointer, and a dial. The top of the transmission rod is provided with a rack, and the gear transmission assembly meshes with the rack and drives the pointer to rotate on the dial.

4. The device for real-time monitoring of extinguishing agent levels in CO2 fire extinguishers according to claim 1, characterized in that, The vertical tube is a metal round tube.

5. The device for real-time monitoring of extinguishing agent levels in CO2 fire extinguishers according to claim 1, characterized in that, The display component includes a vertical indicator, and the top of the transmission rod is provided with an indicator arrow. When the transmission rod moves, it drives the indicator arrow to indicate different positions of the vertical indicator.

6. The device for real-time monitoring of extinguishing agent levels in CO2 fire extinguishers according to claim 5, characterized in that, The vertical indicator can be raised and lowered and installed outside the fire extinguisher tank.

7. A CO2 fire extinguisher, comprising a fire extinguisher canister, characterized in that, The fire extinguisher canister is equipped with a nozzle and a device for real-time monitoring of the extinguishing agent level of the CO2 fire extinguisher as described in any one of claims 1 to 6, wherein the fire extinguisher canister is filled with liquid CO2.

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