Control system and control method for ventilation of ship cargo hold

Abstract

The invention discloses a control system and method for ventilation of a ship cargo hold, and the system comprises a monitoring unit which comprises a plurality of monitoring points disposed in the cargo hold and is used for collecting the concentration parameters of hazardous gases in different regions in the cargo hold in real time; and the control unit is in signal connection with the monitoring unit and is in control connection with a frequency conversion fan of the cargo compartment ventilation system. When the control unit receives a hazardous gas standard exceeding signal output by the monitoring unit, a rotating speed adjusting instruction is automatically generated and output to the frequency conversion fan; the rotating speed adjusting instruction adjusts the rotating speed of the frequency conversion fan to the target rotating speed, and the target rotating speed is not lower than the preset minimum safe rotating speed. Through linkage control of the cargo hold air quality monitoring system and the variable-frequency ventilation system, real-time monitoring of hazardous gas, automatic adjustment of the rotating speed of the fan and automatic regulation and control of multi-stage safety protection are achieved; and on the premise that the safety of the cargo hold is guaranteed, the fan energy consumption can be remarkably reduced, and the ship operation safety, economical efficiency and intelligent level are improved.

Description

A control system and control method for ventilation in ship cargo holds Technical Field

[0001] This application relates to the technical field of ventilation control in ship cargo holds, and more particularly to a control system and control method for ventilation in ship cargo holds. Background Technology

[0002] Cargo hold areas of roll-on / roll-off ships are divided into multiple zones based on the different hazard levels of the cargo. During navigation, berthing, and loading / unloading operations, ventilation must meet the requirement of 10-20 air changes per minute to ensure air quality safety and prevent the accumulation of dangerous gases that could lead to fires or explosions.

[0003] Currently, variable frequency control technology is commonly used for ventilation in the cargo holds of roll-on / roll-off ships. The fans are remotely controlled through the engine room monitoring system. There are usually two modes: loading / unloading and navigation. The fan speed can be adjusted within the range of 20% to 100%.

[0004] While this method reduces power consumption to some extent, it still has significant drawbacks: cargo hold air quality is under "blind control," meaning crew members cannot be aware of the generation or leakage of hazardous gases such as carbon monoxide, nitrogen dioxide, and flammable gases in real time. They can only rely on portable detectors to inspect each floor, which is not only time-consuming and labor-intensive, but also makes it difficult to predict the location of gas accumulation, resulting in untimely and inaccurate test results. Furthermore, to ensure safety, a conservative strategy of increasing fan speed is often adopted, leading to increased power consumption and decreased fuel economy. Summary of the Invention

[0005] The purpose of this invention is to provide a control system and control method for ventilation of ship cargo holds, which can solve the above-mentioned problems existing in the prior art.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] On one hand, a control system for ship cargo hold ventilation is provided, comprising: a monitoring unit including multiple monitoring points installed in the cargo hold for real-time acquisition of hazardous gas concentration parameters in different areas of the cargo hold; and a control unit connected to the monitoring unit and connected to the variable frequency fan control of the cargo hold ventilation system; wherein, when the control unit receives a hazardous gas exceeding the standard signal output by the monitoring unit, it automatically generates and outputs a speed adjustment command to the variable frequency fan; the speed adjustment command adjusts the speed of the variable frequency fan to a target speed, and the target speed is not lower than a preset minimum safe speed.

[0008] Preferably, the monitoring unit includes multiple gas sensors, and the hazardous gases monitored by the gas sensors include carbon monoxide, nitrogen dioxide, and flammable gases.

[0009] Preferably, the control unit includes: a mode selection module for selecting the current operating mode from multiple control modes, wherein the multiple control modes include at least an economic control mode; a signal processing module for receiving the hazardous gas concentration parameter output by the monitoring unit and comparing it with a preset threshold to generate the hazardous gas exceeding the standard signal; and a speed decision module for determining the target speed based on the hazardous gas exceeding the standard signal and generating the speed adjustment command.

[0010] Preferably, in the economic control mode, the target speed is automatically determined by the speed decision module based on the hazardous gas exceeding the standard signal, and the preset minimum safe speed is 50% of the rated speed of the variable frequency fan.

[0011] Preferably, the monitoring unit includes multiple sensors arranged along the length of the cargo hold and in layers on multiple decks. Each sensor independently collects hazardous gas concentration parameters of its area and transmits them to the control unit.

[0012] Preferably, the control unit is further configured to: generate and output a command for the fan to run at full speed when the hazardous gas exceedance signal lasts for a preset duration or the hazardous gas concentration parameter reaches a preset hazardous threshold.

[0013] Preferably, it also includes a human-machine interaction unit, which is signal-connected to the control unit and used to display the real-time hazardous gas concentration, fan operating parameters and alarm information in each area of ​​the cargo compartment.

[0014] Preferably, the control unit is configured to set corresponding preset minimum safe speeds for different hazard level areas of the cargo hold, and the preset minimum safe speeds for different hazard level areas are different from each other.

[0015] On the other hand, this disclosure also provides a control method for ventilation in a ship's cargo hold, which includes the following steps: real-time acquisition of hazardous gas concentration parameters in different areas of the cargo hold through monitoring units installed at multiple monitoring points in the cargo hold; comparison of the hazardous gas concentration parameters with preset thresholds, and generation of a hazardous gas exceedance signal when the concentration parameter in any area reaches or exceeds the preset threshold; automatic determination of the target speed of the variable frequency fan based on the hazardous gas exceedance signal, and generation of a speed adjustment command; and sending the speed adjustment command to the variable frequency fan to adjust its speed to the target speed, wherein the target speed is not lower than a preset minimum safe speed.

[0016] Preferably, it also includes an emergency control step: when the hazardous gas exceedance signal continues for more than a preset duration or the hazardous gas concentration parameter reaches a preset hazardous threshold, a command to run the fan at full speed is generated and executed.

[0017] The beneficial effects of this application are as follows: 1. By setting up a multi-point, layered gas sensor network in the cargo hold, it is possible to collect the concentration parameters of dangerous gases such as carbon monoxide, nitrogen dioxide, and flammable gases in real time and continuously, thereby obtaining detailed data on the air quality in the cargo hold in a timely manner.

[0018] 2. By setting a minimum safe operating speed of no less than 50% of the rated speed, the basic ventilation volume of the cargo hold is ensured under all circumstances, fundamentally eliminating the risk of fire or explosion caused by insufficient ventilation. Furthermore, this invention avoids overreacting to instantaneous fluctuations and ensures timely response in real hazardous situations. Different minimum safe operating speeds and alarm thresholds are set for different hazard levels in the cargo hold, providing higher levels of safety protection to high-risk areas, achieving risk-level control, and thus improving overall safety.

[0019] 3. By setting different minimum safe speeds, lower basic ventilation volumes can be used in low-risk areas, maximizing energy-saving effects while ensuring safety, and further realizing refined energy efficiency management. Attached Figure Description

[0020] The present application will now be described in further detail with reference to the accompanying drawings and embodiments.

[0021] Figure 1 is a schematic diagram of the module structure of a control system for ship cargo hold ventilation according to an embodiment of this application; Figure 2 is a schematic diagram of the flow chart of a control method for ship cargo hold ventilation according to an embodiment of this application.

[0022] In the diagram: 100, monitoring unit; 110, gas sensor; 200, control unit; 210, mode selection module; 220, signal processing module; 230, speed decision module; 300, human-machine interaction unit. Detailed Implementation

[0023] To make the technical problems solved by this application, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of this application are further described in detail below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0026] As shown in Figure 1, this embodiment provides a control system for ventilation of ship cargo holds, which includes a monitoring unit 100 and a control unit 200. The monitoring unit 100 includes multiple monitoring points set at different locations in the cargo hold, and each monitoring point is equipped with a gas sensor 110, which collects the concentration parameters of hazardous gases in that area in real time.

[0027] In this embodiment, monitoring points can be set at regular intervals along the length of the cargo hold, and vertically, monitoring points can be set for each cargo hold deck to ensure coverage of all potential blind spots where gas accumulation may occur. Each monitoring point uploads the collected concentration parameters in real time via a fieldbus (such as CAN bus, RS485 bus, or Ethernet).

[0028] Furthermore, the control unit 200 can be implemented using an industrial-grade programmable logic controller (PLC) or an embedded industrial computer. It is connected to the monitoring unit 100 via a communication interface signal, and at the same time, it establishes a control connection with the variable frequency fan of the cargo compartment ventilation system via an analog output module or a communication protocol (such as Modbus TCP).

[0029] It should be noted that the control unit 200 has a built-in preset algorithm logic. Based on this algorithm logic, when the control unit 200 receives a hazardous gas exceeding the standard signal from the monitoring unit 100, it automatically calculates and outputs a speed adjustment command to the variable frequency fan, adjusting the fan speed to the target speed, and the target speed is not lower than the preset minimum safe speed (e.g., 50% of the rated speed).

[0030] For example, during normal ship operation, monitoring unit 100 continuously monitors the concentration of hazardous gases in various areas. Once the concentration in a certain area exceeds a preset safety threshold, such as a CO concentration of 50 ppm or a flammable gas concentration of 10% of the lower explosive limit, monitoring unit 100 generates a hazardous gas exceedance signal. Upon receiving this signal, control unit 200 immediately determines the required target speed based on the number of areas exceeding the limit, the exceedance concentration value, and the preset control strategy. For example, it increases the fan speed from 50% to 80% and outputs a command to drive the variable frequency fan to speed up. At the same time, control unit 200 ensures that the fan speed does not fall below the preset minimum safe speed under any circumstances to prevent insufficient ventilation due to excessively low speed.

[0031] In some implementations, the control unit 200 can be integrated into the ship's engine room monitoring system, utilizing the existing hardware platform and communication network of the engine room monitoring system by adding corresponding control software modules. In this case, the monitoring unit 100 serves as an input module for field devices accessing the engine room monitoring system, the control logic is executed by the central processing unit of the engine room monitoring system, and the output commands are sent to the frequency converter through the output module of the engine room monitoring system.

[0032] Understandably, by setting up a monitoring unit 100 to collect the concentration of hazardous gases in real time and using a control unit 200 to automatically adjust the fan speed, closed-loop automatic control of cargo hold ventilation is achieved, enabling the ventilation system to dynamically adjust operating parameters according to actual air quality requirements, thus ensuring cargo hold safety and avoiding ineffective energy consumption.

[0033] Specifically, the monitoring unit 100 includes multiple gas sensors 110, which include at least a carbon monoxide sensor, a nitrogen dioxide sensor, and a flammable gas sensor 110. The carbon monoxide sensor detects CO gas generated by cargo oxidation or backflow of internal combustion engine exhaust; the nitrogen dioxide sensor detects NO2 gas that may originate from diesel engine exhaust or the self-decomposition of certain cargo; and the flammable gas sensor 110 detects leaks of flammable gases such as gasoline vapor, liquefied petroleum gas, and methane.

[0034] Specifically, in actual installation, the three types of sensors can be integrated into one sensor box, with one sensor box installed at each monitoring point, to achieve simultaneous measurement of multiple parameters.

[0035] For example, the sensor output signal is a 4-20mA current signal or an RS485 digital signal, which is directly connected to the analog input module or communication module of the control unit 200.

[0036] Understandably, by monitoring multiple hazardous gases, it is possible to comprehensively cover all kinds of potential safety hazards in the cargo holds of roll-on / roll-off ships, ensuring that any potential hazardous gas leaks can be detected in a timely manner, thereby improving the reliability and safety of the system.

[0037] In one embodiment, the control unit 200 includes a mode selection module 210, a signal processing module 220, and a speed decision module 230.

[0038] Specifically, the mode selection module 210 is used to select the current working mode among multiple control modes.

[0039] In this embodiment, the control unit 200 has at least two built-in modes: an "economic control mode" and a "manual control mode". The mode selection module 210 allows the current operating mode to be changed by receiving mode switching commands from the human-machine interface or the engine room monitoring system. For example, when the ship is in port loading and unloading cargo, the loading and unloading mode, which corresponds to a fixed speed mode, can be manually selected; when the ship is sailing, it can switch to the economic control mode.

[0040] Furthermore, the signal processing module 220 receives the hazardous gas concentration parameters output by the monitoring unit 100 and compares them with preset thresholds. The signal processing module 220 has multiple built-in comparators, setting a primary alarm threshold (exceedance signal trigger value) and a secondary alarm threshold (hazard threshold) for each hazardous gas. When the concentration parameter at any monitoring point exceeds the primary alarm threshold, the signal processing module 220 generates a hazardous gas exceedance signal and transmits this signal to the speed decision module 230.

[0041] Furthermore, the speed decision module 230 is used to determine the target speed based on the hazardous gas exceedance signal and generate a corresponding speed adjustment command.

[0042] For example, the speed decision module 230 may have a built-in decision algorithm, which can be a rule-based expert system. For instance, if only a single monitoring point slightly exceeds the limit (the exceedance is less than 20% of the threshold), the target speed is increased by 10% from the current speed; if multiple monitoring points exceed the limit simultaneously, or if a monitoring point severely exceeds the limit (the exceedance is greater than 50% of the threshold), the target speed is directly increased to 80% or higher; if all monitoring points are normal, the target speed gradually decreases to the preset minimum safe speed. The speed decision module 230 can convert the target speed into a signal recognizable by the frequency converter and send it through the output module.

[0043] Understandably, the mode selection module 210 can provide flexible control methods, while the signal processing module 220 can ensure the timeliness of alarms, and the speed decision module 230 can realize dynamic adjustment of speed.

[0044] In one embodiment, the economic control mode is the ECO-PORT economic control mode. In the economic control mode, the target speed is automatically determined by the speed decision module 230 based on the hazardous gas exceedance signal, and the preset minimum safe speed is 50% of the rated speed of the variable frequency fan.

[0045] Specifically, when the vessel is underway or docked and no loading or unloading is required, the operator can select the ECO-PORT economic control mode through the human-machine interface. At this time, the control unit 200 locks the lower limit of the fan speed at 50% of the rated speed. As long as the concentration of hazardous gas at all monitoring points is below the first-level alarm threshold, the fan operates at 50% speed to maintain basic ventilation with minimal energy consumption. If the concentration at any monitoring point exceeds the limit, the speed decision module 230 immediately calculates the target speed (e.g., increasing from 50% to 70% or higher) and drives the fan to increase its speed until the hazardous gas concentration drops to a safe range, after which it gradually decreases back to 50%.

[0046] It is important to note that, to ensure safety, even if the concentration of hazardous gas fluctuates within a short period, the speed decision module 230 employs a hysteresis control strategy to avoid frequent acceleration and deceleration of the fan. For example, the speed is only allowed to be reduced when the concentration remains below the alarm threshold for 30 consecutive seconds.

[0047] Understandably, the ECO-PORT economic control mode, while ensuring safety, maximizes energy savings for the ventilation system and improves fuel economy by limiting the minimum safe operating speed to 50%. Simultaneously, the automatic adjustment mechanism avoids the lag and inaccuracy of manual operation, ensuring the ventilation system always operates at the optimal balance between safety and energy efficiency.

[0048] In one embodiment, the monitoring unit 100 includes multiple sensors arranged along the length of the cargo hold and across multiple decks. Specifically, on each cargo hold deck, a sensor node can be installed every 10-15 meters along the longitudinal direction of the ship, with a gas sensor 110 for detecting CO, NO2, and flammable gases installed at each node. For large cargo holds exceeding 50 meters in length, monitoring points can be installed at the bow, midships, and stern. Vertically, an independent sensor network is arranged for each deck, with sensors independently collecting hazardous gas concentration parameters for their respective decks and transmitting the data to the control unit 200 via a bus.

[0049] It should be noted that the installation location, number, and corresponding cargo compartment area coordinates of all sensors are pre-entered into the control unit 200. The control unit 200 can quickly locate the out-of-range area based on the sensor number and display the location of the out-of-range area graphically on the human-machine interface.

[0050] Understandably, by arranging sensors in a longitudinal and vertical layered manner, it is possible to achieve comprehensive monitoring of the entire cargo hold without blind spots, accurately capturing gas anomalies in any area. This solves the problem that traditional portable detectors can only sample localized areas and the range of gas accumulation is unpredictable. Furthermore, independently collecting parameters from each area provides a data foundation for subsequent refined control.

[0051] In one embodiment, the control unit 200 is also used to generate and output a command for the fan to run at full speed when the hazardous gas exceedance signal lasts for a preset duration or the hazardous gas concentration parameter reaches a preset hazardous threshold.

[0052] Specifically, the control unit 200 is equipped with a timer that starts when the signal processing module 220 generates a hazardous gas exceedance signal. If the exceedance signal is not eliminated within a preset time, i.e., the hazardous gas concentration is still higher than the first-level alarm threshold, the control unit 200 determines it to be a continuous hazardous situation and automatically outputs a command to run the fan at full speed, increasing the frequency of the variable frequency fan to the rated speed and forcing maximum ventilation.

[0053] On the other hand, if the concentration of hazardous gas at any monitoring point reaches a preset hazardous threshold, such as a CO concentration of 200 ppm or a flammable gas concentration of 25% of the lower explosive limit, a full-speed operation command will be triggered directly without waiting for a timer. At the same time, the control unit 200 will mark the event as an emergency alarm, issue an audible and visual alarm through the human-machine interface unit 300, and display an alarm window on the cabin monitoring system.

[0054] Understandably, by setting dual trigger conditions of duration and danger threshold, it is possible to avoid overreacting to momentary exceedances (such as sensor false alarms) while ensuring that maximum ventilation measures can be taken immediately in real dangerous situations, thus greatly improving the system's safety redundancy and emergency response capabilities.

[0055] In one embodiment, a human-machine interface unit 300 is also included. The human-machine interface unit 300 is signal-connected to the control unit 200 and is used to display the real-time hazardous gas concentration, fan operating parameters and alarm information in each area of ​​the cargo hold.

[0056] For example, the human-machine interface unit 300 can be a standalone touchscreen display installed in the engine room control room or bridge, or it can be a software interface integrated into the ship's engine room monitoring system workstation. Specifically, the human-machine interface can graphically display a two-dimensional or three-dimensional layout of the cargo hold, using different colors to indicate the real-time concentration value of each monitoring point: green indicates safety, yellow indicates approaching the alarm threshold, and red indicates exceeding the limit. Simultaneously, the interface displays real-time information such as the current fan operating frequency, speed percentage, operating mode (economic / manual / emergency), and cumulative operating time. When an alarm occurs, the interface automatically pops up an alarm list, displaying the alarm time, area, gas type, and concentration value, and supports querying and exporting historical alarm records.

[0057] Understandably, the human-machine interface unit 300 enables crew members to intuitively grasp the air quality and fan operation status in the cargo hold, promptly identify potential hazards, and easily configure the system. At the same time, the graphical interface greatly reduces operational difficulty and improves human-machine efficiency.

[0058] In one embodiment, this embodiment, based on the above-described embodiment, limits the regional differentiation setting of the minimum safe speed.

[0059] Specifically, the cargo holds of roll-on / roll-off (Ro-Ro) ships are typically divided into different zones based on the hazard level of the cargo, such as dangerous goods zones, general cargo zones, and vehicle access zones. Different zones have different ventilation requirements; dangerous goods zones require higher basic ventilation volumes to prevent gas buildup, while general cargo zones can use relatively lower basic ventilation volumes to save energy.

[0060] Based on this, in this embodiment, the control unit 200 is configured to set corresponding preset minimum safe speeds for different hazard level areas of the cargo hold, and the preset minimum safe speeds for different hazard level areas are different. Specifically, the control unit 200 stores a cargo hold area division map, with each monitoring point corresponding to one area, and each area associated with a minimum safe speed coefficient. For example, the minimum safe speed for the hazardous goods area is set to 60% of the rated speed, for the general cargo area it is set to 50%, and for the vehicle passage area it is set to 40%.

[0061] When the control unit 200 performs speed adjustment, it does not uniformly adopt the same minimum safe speed. Instead, it selects the minimum safe speed corresponding to the current hazard level of the area exceeding the standard as the benchmark. If multiple areas exceed the standard simultaneously, the maximum value among them is taken as the global minimum safe speed to ensure that the highest risk area receives sufficient ventilation.

[0062] Understandably, by setting minimum safe operating speeds based on regional differences, ventilation control can be refined. While ensuring safety in high-risk areas, energy consumption in low-risk areas can be further optimized, maximizing energy-saving effects.

[0063] Please refer to Figure 2. On the other hand, this disclosure also provides a control method for ventilation of ship cargo holds, which can be applied to the system of any of the foregoing embodiments.

[0064] Specifically, the control method for ventilation of ship cargo holds provided in this disclosure includes the following steps.

[0065] First, step S1 is executed, in which monitoring units 100, which are set at multiple monitoring points in the cargo hold, collect hazardous gas concentration parameters in different areas of the cargo hold in real time. In this step, the monitoring unit 100 can poll each sensor at a preset sampling frequency (e.g., once / second), and send the gas concentration data of each monitoring point to the control unit 200 after packaging.

[0066] Then, step S2 is executed, comparing the hazardous gas concentration parameters with preset thresholds. When the concentration parameter of any area reaches or exceeds the preset threshold, a hazardous gas exceedance signal is generated. This signal may include information such as the identifier of the exceedance area, the type of exceedance gas, and the exceedance concentration value.

[0067] Furthermore, in step S3, based on the hazardous gas exceedance signal, the target speed of the variable frequency fan is automatically determined, and a speed adjustment command is generated. It should be noted that the determination rule can employ the decision-making algorithm provided in the above embodiments. For example, if only one area slightly exceeds the limit, the current speed is increased by 10% but not less than 50%; if multiple areas exceed the limit or severely exceed it, the speed is directly increased to 80% or higher.

[0068] Furthermore, in step S4, a speed adjustment command is sent to the variable frequency fan to adjust its speed to the target speed, and the target speed is not lower than the preset minimum safe speed.

[0069] It should be noted that the control method executes the above steps in a loop, continuously monitors air quality and dynamically adjusts the fan speed to form a closed-loop control.

[0070] In one embodiment, based on the above control method, an emergency control step is also included.

[0071] Specifically, in the emergency control steps, when the hazardous gas exceedance signal lasts for more than a preset duration or the hazardous gas concentration parameter reaches a preset hazardous threshold, a command to run the fan at full speed is generated and executed.

[0072] For example, after a hazardous gas exceedance signal is generated in step S2, the control unit 200 may start a timer. If the exceedance signal does not disappear within a preset time (i.e., the concentration remains above the alarm threshold), it is determined to be a persistent hazardous situation, triggering emergency control and generating a command to run the fan at full speed. Simultaneously, the control unit 200 monitors the concentration parameters collected in step S1 in real time. If the concentration parameter at any monitoring point reaches a preset "hazard threshold" (secondary alarm value), emergency control is immediately triggered without waiting for the timer to run.

[0073] Furthermore, while executing the full-speed operation command of the wind turbine, the control unit 200 also issues an audible and visual alarm through the human-machine interface unit 300 and records the emergency event in the log. During emergency operation, the control unit 200 continuously monitors concentration changes. When the concentration at all monitoring points drops to a safe level (e.g., below 80% of the alarm threshold) and remains so for a certain period of time (e.g., 2 minutes), it can automatically exit the emergency state and return to the previous control mode (e.g., economic mode). In addition, operators can also manually reset the emergency state.

[0074] Understandably, this method can achieve a complete closed loop from detection to control, with a high degree of automation and fast response speed.

[0075] In summary, this disclosure provides a control system and method for ventilation in ship cargo holds. By setting up a multi-point, layered network of gas sensors 110 in the cargo hold, the concentration parameters of hazardous gases such as carbon monoxide, nitrogen dioxide, and flammable gases can be collected in real time and continuously, thereby obtaining detailed data on the air quality in the cargo hold in a timely manner.

[0076] By setting a minimum safe operating speed of no less than 50% of the rated speed, the basic ventilation volume of the cargo hold is ensured under all circumstances, fundamentally eliminating the risk of fire or explosion caused by insufficient ventilation. Furthermore, this invention avoids overreacting to instantaneous fluctuations and ensures timely response in real hazardous situations. Different minimum safe operating speeds and alarm thresholds are set for different hazard levels in the cargo hold, providing higher levels of safety protection to high-risk areas, achieving risk-level control, and thus improving overall safety.

[0077] By setting different minimum safe operating speeds, lower basic ventilation volumes can be used in low-risk areas, maximizing energy savings while ensuring safety, and further achieving refined energy efficiency management.

[0078] In the description herein, it should be understood that the terms "upper," "lower," "left," "right," and other orientations or positional relationships are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used merely for descriptive distinction and have no special meaning.

[0079] In the description of this specification, references to terms such as "an embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0080] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0081] The technical principles of this application have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of this application without inventive effort, and these embodiments will all fall within the scope of protection of this application.

Claims

1. A control system for ventilation in ship cargo holds, characterized in that, include: The monitoring unit (100) includes multiple monitoring points installed in the cargo hold for real-time collection of hazardous gas concentration parameters in different areas of the cargo hold. The control unit (200) is connected to the monitoring unit (100) via signal and to the variable frequency fan control of the cargo compartment ventilation system. When the control unit (200) receives a hazardous gas exceeding the standard signal from the monitoring unit (100), it automatically generates and outputs a speed adjustment command to the variable frequency fan. The speed adjustment command adjusts the speed of the variable frequency fan to a target speed, and the target speed is not lower than a preset minimum safe speed.

2. The control system for ship cargo hold ventilation according to claim 1, characterized in that, The monitoring unit (100) includes multiple gas sensors (110), and the hazardous gases monitored by the gas sensors (110) include carbon monoxide, nitrogen dioxide and flammable gases.

3. The control system for ship cargo hold ventilation according to claim 1, characterized in that, The control unit (200) includes: a mode selection module (210) for selecting the current working mode among multiple control modes, wherein the multiple control modes include at least an economic control mode; a signal processing module (220) for receiving the hazardous gas concentration parameters output by the monitoring unit (100), comparing them with a preset threshold, and generating the hazardous gas exceeding the standard signal; and a speed decision module (230) for determining the target speed based on the hazardous gas exceeding the standard signal and generating the speed adjustment command.

4. The control system for ship cargo hold ventilation according to claim 3, characterized in that, In the economic control mode, the target speed is automatically determined by the speed decision module (230) based on the dangerous gas exceeding the standard signal, and the preset minimum safe speed is 50% of the rated speed of the variable frequency fan.

5. The control system for ship cargo hold ventilation according to claim 1, characterized in that, The monitoring unit (100) includes multiple sensors arranged along the length of the cargo hold and in layers on the multi-deck structure. Each sensor independently collects hazardous gas concentration parameters of its area and transmits them to the control unit (200).

6. The control system for ship cargo hold ventilation according to claim 1, characterized in that, The control unit (200) is also used to generate and output a full-speed operation command for the fan when the dangerous gas exceedance signal lasts for a preset duration or the dangerous gas concentration parameter reaches a preset danger threshold.

7. The control system for ship cargo hold ventilation according to claim 1, characterized in that, It also includes a human-machine interface unit (300), which is connected to the control unit (200) for displaying the real-time hazardous gas concentration, fan operating parameters and alarm information in each area of ​​the cargo hold.

8. The control system for ship cargo hold ventilation according to claim 1, characterized in that, The control unit (200) is configured to set the corresponding preset minimum safe speed according to the different danger level areas of the cargo compartment, and the preset minimum safe speeds corresponding to the different danger level areas are different.

9. A control method for ventilation in ship cargo holds, characterized in that, Includes the following steps: The monitoring unit (100) is set at multiple monitoring points in the cargo hold to collect hazardous gas concentration parameters in different areas of the cargo hold in real time; the hazardous gas concentration parameters are compared with preset thresholds, and when the concentration parameter of any area reaches or exceeds the preset threshold, a hazardous gas exceedance signal is generated; based on the hazardous gas exceedance signal, the target speed of the variable frequency fan is automatically determined, and a speed adjustment command is generated; the speed adjustment command is sent to the variable frequency fan to adjust its speed to the target speed, and the target speed is not lower than the preset minimum safe speed.

10. The control method for ship cargo hold ventilation according to claim 9, characterized in that, It also includes emergency control steps: when the hazardous gas exceedance signal lasts for more than a preset duration or the hazardous gas concentration parameter reaches a preset danger threshold, a command to run the fan at full speed is generated and executed.

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