Marine variable air volume air diffuser

Abstract

The utility model discloses a kind of marine variable air volume air distributor, the air distributor includes: shell;Plug;Electric actuator, its output shaft is connected with plug through magnetic coupling;Heating coil pipe, it is set in the bottom of inner cavity;Temperature sensor, it is set in inner cavity middle position close to heating coil pipe;Temperature controller;And controller, it is set in inner cavity, controller is connected with temperature controller, temperature sensor, electric actuator and heating coil pipe respectively;Wherein temperature sensor is connected to controller by 1 / NTC1 GND interface one-way connection;Temperature controller and controller are connected in two-way communication;Electric actuator is connected with the J2 communication interface of controller by 1PKU / 2 GY R / 3BK G0 / 4RD G four-core cable and establishes RS485 two-way communication link connection.This utility model improves the adjustment precision, reduces system energy consumption.

Description

Technical Field

[0001] This utility model relates to the field of marine ventilation equipment, specifically to a marine variable air volume distributor, which is particularly suitable for variable air volume distributors in luxury cruise ship cabins. Background Technology

[0002] As a key component of a ship's ventilation system, the air distributor plays a crucial role in maintaining a comfortable and healthy environment within the cabin. It is responsible for evenly distributing treated air to every corner of the cabin, ensuring that temperature, humidity, and air quality in different areas meet requirements. In today's shipbuilding industry, with ever-increasing demands for ship comfort, energy efficiency, and safety, the technical shortcomings of existing ship air distributors are becoming increasingly apparent.

[0003] For manually adjustable ship air distributors, there is usually a large error. According to the measured data of ISO 1461:2022, the manual adjustment error can reach ±18%. On the other hand, manual adjustment is labor-intensive and requires a certain level of skill or experience from the operators, which increases labor costs. Furthermore, manual adjustment is usually not fast enough and has a certain lag. This means that it is difficult to accurately control the amount of air delivered into the cabin, which may lead to insufficient or excessive air supply in some areas, affecting the comfort of the occupants and hindering the precise control of the ship's environment. In addition, this lag will also increase the energy consumption of the ship's ventilation system.

[0004] The technical shortcomings of electrically adjustable air distributors are also quite obvious. Mechanically, the device that controls valve opening via gear transmission has a gap between the gears, resulting in a valve opening error of up to ±3.2% (measured by a laser displacement sensor). This affects the accuracy of airflow regulation, and consequently, the performance of the entire ventilation system. Furthermore, due to the different control processes and modes of electrically adjustable air distributors, the precision of their airflow control also needs to be considered.

[0005] Overall, existing ship air distributors have many shortcomings in terms of air volume regulation accuracy and system energy efficiency, and need to be improved. Utility Model Content

[0006] This utility model provides a marine variable air volume distributor. Through the connection relationship of various components, the distributor forms multiple coordinated hardware control loops that simultaneously adjust the temperature inside the distributor housing, the opening of the plug, and the power of the heating coil. This keeps the air volume adjustment accuracy within ±2.5% (based on ISO 5211 standard testing), effectively improving the performance and reliability of the cruise ship ventilation system, reducing its energy consumption, and providing passengers with a more comfortable and safe environment.

[0007] According to one aspect of this utility model, a marine variable air volume (VAV) air distributor is provided. The air distributor includes: a housing, on which an air inlet connector for connecting to a cooling air duct and an air outlet connector for connecting to a supply air duct are provided; a plug, the plug being used to cover the opening of the air inlet connector to limit the amount of gas entering the housing, the plug being disposed in the inner cavity of the housing; and an electric actuator, the output shaft of the electric actuator being connected to the plug via a magnetic coupling to eliminate transmission backlash and ensure valve opening control accuracy ≤0.5%, the electric actuator being used to drive the plug relative to the air inlet connector. The system comprises: an electric actuator for controlling the opening of the air intake connector, the electric actuator being disposed within the inner cavity; a heating coil disposed at the bottom of the inner cavity for heating the air within the inner cavity; a temperature sensor disposed in the middle of the inner cavity near the heating coil for sensing the temperature within the inner cavity; a temperature controller disposed within the inner cavity; and a controller disposed within the inner cavity, the controller being connected to the temperature controller, the temperature sensor, the electric actuator, and the heating coil, respectively; wherein the temperature sensor is unidirectionally connected to the controller via an I / NTC1 GND interface; the temperature controller and the controller are bidirectionally connected; the electric actuator is connected to the controller via a 1PKU / 2 GY Y / 3BK G0 / 4RD G four-core cable to establish an RS485 bidirectional communication link with the controller's J2 communication interface; and optionally, the electric actuator is unidirectionally connected to the temperature controller.

[0008] In another preferred embodiment, the air distributor includes a junction box disposed on the outside of the housing. The junction box contains physically isolated wiring for high-voltage lines (PE / N / L, etc.) and low-voltage lines (GY / BK, etc.), reducing EMC interference by more than 40%. In another preferred embodiment, the temperature sensor is used to measure the temperature within the cavity; preferably, it is used to measure the temperature near the heating coil.

[0009] In another preferred embodiment, the temperature controller includes a first PID module, which is used to obtain the target opening degree of the plug based on the target temperature set by the user and the real-time medium temperature from the temperature sensor.

[0010] In another preferred embodiment, the electric actuator monitors the valve position in real time by means of an incremental encoder mounted at the rear end of its servo motor, and converts the mechanical displacement into A / B phase digital pulse signals.

[0011] In another preferred embodiment, the controller includes a PWM module, which includes a timer and a comparator. In the controller, the pulses of the incremental encoder are acquired through the timer interrupt with a period of 1ms. The comparator compares the timer count value with the target opening degree of the plug. Based on the comparison result, a 4-20mA valve position control signal with an opening degree of 0-100% is sent to the electric actuator to control the movement of the motor in the electric actuator, thereby controlling the opening degree of the plug.

[0012] In another preferred embodiment, the temperature controller includes a second PID module, which generates a temperature compensation coefficient based on the user-set target temperature, the real-time medium temperature from the temperature sensor, and optionally the opening degree of the plug.

[0013] In another preferred embodiment, the controller includes a PWM module that adjusts the PWM duty cycle of the heating coil according to a temperature compensation coefficient from the thermostat.

[0014] In another preferred embodiment, the controller is connected to the temperature sensor via an NTC thermistor signal path.

[0015] In another preferred embodiment, the high-voltage and low-voltage circuits in the junction box are respectively connected to an external power source; the electric actuator, the thermostat, and the controller are respectively connected to the low-voltage circuit; and the heating coil is connected to the high-voltage circuit. These components are indirectly connected to an external power source through the junction box to obtain power from that external power source.

[0016] In another preferred embodiment, the cooling duct is connected to the external environment, and the air supply duct is connected to the internal space to be regulated.

[0017] In another preferred embodiment, the plug covers the opening of the air intake connector from the inside, i.e., from the inner cavity.

[0018] In another preferred embodiment, the electric actuator is fixed to a seat plate in the cavity.

[0019] In another preferred embodiment, the controller is fixed to a seat plate in the cavity.

[0020] In another preferred embodiment, the temperature sensor is a temperature sensor.

[0021] In another preferred embodiment, the controller is an AC controller.

[0022] In another preferred embodiment, the outer shell has a double-layer structure with an insulation layer filling the middle layer.

[0023] In another preferred embodiment, the insulation layer is a glass wool and / or a rock wool layer.

[0024] In another preferred embodiment, the controller includes a Σ-ΔADC converter, one end of which is connected to the temperature sensor and the other end of which is connected to the temperature controller.

[0025] In another preferred embodiment, the controller is connected to a 12 / 24VAC power input module via a power line consisting of a PE line (safety ground) and phase lines (L / N) through the PE / N / L port of the terminal block, providing a wide voltage input to the controller. Its output terminal supplies power to the heating coil through the Ltrl5 port.

[0026] In another preferred embodiment, both the PE line (safety ground) and the phase lines (L / N) are led out through terminals and connected to the PE / L / N interface on the controller, generating isolated low-voltage circuits through the AC-DC conversion module integrated inside the controller.

[0027] In another preferred embodiment, the analog channel is a 10 / 00-10V interface; the digital channel is a 6 / D1, 8 / D2, 4 / D3 interface.

[0028] In another preferred embodiment, the controller is connected to the temperature sensor via an NTC thermistor.

[0029] In another preferred embodiment, the power output terminal of the heating coil is provided with a solid-state relay, and the controller is connected to the heating coil through the solid-state relay.

[0030] In another preferred embodiment, the controller has a PWM output port connected to the solid-state relay.

[0031] In another preferred embodiment, the controller controls the solid-state relay via PWM duty cycle, thereby controlling the operating state of the heating coil.

[0032] In another preferred embodiment, the temperature sensor detects the medium temperature in real time via an NTC1 thermistor network.

[0033] In another preferred embodiment, a redundant PE grounding terminal is provided in the terminal block.

[0034] In another preferred embodiment, the controller and the temperature controller are connected via a 6 / D1 communication interface to achieve bidirectional synchronization of control parameters.

[0035] In another preferred embodiment, the temperature sensor is disposed 5D above the heating coil, where D is the diameter of the heating coil.

[0036] In another preferred embodiment, the temperature controller is provided with an over-temperature protection module. The temperature controller is connected to the electric actuator through its 9 / I0-10V interface, which is activated when the temperature gradient change rate of the temperature sensor is >5℃ / s.

[0037] In another preferred embodiment, the controller is equipped with an audible and visual alarm that is activated when the temperature gradient change rate of the temperature sensor is >5℃ / s or the leakage current is >30mA.

[0038] The marine variable air volume distributor of this application: The electric actuator for the air distributor in this application is powered by a micro servo motor or stepper motor, with accuracy far exceeding that of ordinary AC motors. An incremental encoder can measure the absolute opening position of the valve in real time and with high precision. The AC controller compares the actual position fed back by the encoder with the set position to obtain a precise control signal to drive the motor until the error is eliminated. The electric actuator uses a servo / stepper motor, which has high start-stop torque, fast acceleration, and an extremely short time from start-up to reaching the predetermined speed. Employing a fieldbus (such as Modbus RTU / TPC, PROFINET, BACnet), the command transmission speed is in the millisecond range, reducing transmission time and making the response faster. The device uses a safety extra-low voltage (SELV) power supply, such as 24V DC. Even in the event of leakage, the voltage remains within a safe range; the device's metal casing is reliably grounded, ensuring that leakage current is quickly conducted to the ground, triggering protection. Attached Figure Description

[0039] For a more complete understanding of this invention, reference can be made to the following description of exemplary embodiments taken in conjunction with the accompanying drawings, in which: Figure 1 A front view of a marine variable air volume distributor according to a preferred embodiment of the present invention is shown. Figure 2 It shows Figure 1 A cross-sectional view of a variable air volume air distributor for shipbuilding. Figure 3 It shows Figure 1 Another cross-sectional view of the variable air volume air distributor for shipbuilding. Figure 4 It shows Figure 1 Wiring diagram of a variable air volume air distributor for shipbuilding.

[0040] List of reference numerals 1-Plug, 2-AC controller, 3-Terminal block, 4-Thermostat, 5-Heating coil, 6-Electric actuator, 7-Temperature sensor, 8-Air inlet connector, 9-Air distribution box housing, 10-Air supply connector, 11-Seat plate, 12-Insulation cotton. Detailed Implementation

[0041] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0042] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this patent application description and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” indicate that the elements or objects preceding “comprising” or “including” encompass the elements or objects listed following “comprising” or “including” and their equivalents, and do not exclude other elements or objects.

[0043] As used in this article, the term "power line" refers to a circuit that transmits voltages greater than 36V (or more precisely, AC 50V / DC 120V) and often serves to drive electrical power.

[0044] As used in this article, the term "low-voltage circuit" refers to electrical circuits that transmit voltages below 50V (commonly 12V or 24V), primarily used for signal, data, and control purposes, rather than for transmitting power.

[0045] In existing technologies, marine air distributors suffer from insufficient airflow adjustment precision, significant noise at high airflow rates affecting passenger experience, reliance on manual operation, lack of automated control, and inability to dynamically adjust according to cabin environment, leading to energy waste. Therefore, this embodiment provides a marine variable airflow air distributor.

[0046] like Figures 1-3As shown, the marine variable air volume distributor includes a distribution box shell (9), which has inner and outer double layers with insulation cotton (12) filling the middle. The top of the distribution box shell (9) is provided with an air inlet connector (8) for connecting to the cold air duct, and the side is provided with an air supply connector (10) for connecting to the duct (e.g., air supply duct) connected to the regulated space. It is ensured that all components are installed firmly, connected tightly, and without leakage. The shell structure of the luxury cruise ship variable air volume distributor is formed by the cooperation between the distribution box shell (9), the air inlet connector (8), the air supply connector (10), and the insulation cotton (12). The insulation cotton between the shell and the connector can effectively ensure the temperature of the output air, while absorbing and reducing sound transmission, achieving a good sound insulation effect. The junction box is located on the left side of the shell and is provided with wiring terminals (3), such as Figure 1 As shown in the diagram. When the input airflow enters the air distribution box housing (9) through the air inlet connector (8), the air inlet connector (8) controls its opening degree through the plug (1), and controls the movement of the plug (1) through the electric actuator (6), thereby adjusting the airflow entering the air distribution box housing (9). The electric actuator (6) is fixed on the base plate (11) and is adjusted by the AC controller (2). The electric actuator (6) establishes an RS485 bidirectional communication link with the J2 communication interface of the AC controller (2) through a 1PKU / 2 GY Y / 3BK G0 / 4RD G four-core cable. The AC controller (2) is fixed on the base plate (11), and the power supply line group consisting of the PE line (safety ground) and the phase line (L / N) is connected to the AC power 12 / 24VAC power input module through the PE / N / L port of the terminal block (3) to provide a wide voltage input for the AC controller (2). The power input module also supplies power to other components of this air diffuser, such as the electric actuator (6), heating coil (5), temperature controller (4), and / or temperature sensor (7), meaning that the power input module forms an electrical connection with the aforementioned components. For example, the output of the power input module supplies power to the heating coil (5) through ports Ltrl4 and Ltrl5. The power output of the heating coil (5) is equipped with a solid-state relay, whose control signal comes from the PWM output port of the AC controller (2). The AC controller (2) establishes an NTC thermistor signal path with the temperature sensor (7) through interfaces 1 / NTC1GND and 2 / NTC1. The temperature controller (4) is connected to the corresponding ports of the AC controller (2) through analog channels (10 / O0-10V interface) and digital channels (5 / D1 GND interface) to establish a signal path. The AC controller (2) and the temperature controller (4) can achieve bidirectional synchronization of control parameters. The valve position feedback signal of the electric actuator (6) is also transmitted back to the temperature controller (4) through the 3 / D3 GND interface.

[0047] The AC controller must have both an Ethernet port and an RS485 port. It can be any PLC or automation controller that supports Modbus-TCP master / client and Modbus-RTU master functions. For example, Siemens (S7-1200 / 1500), Schneider (Modicon M series), Omron, Delta, Inovance, Beckhoff and any other mainstream PLC or automation controller can be selected.

[0048] The temperature controller must support RS485 Modbus-RTU communication and have 0-10V analog output function. It can be selected from Shimaden SR series, Omron E5CN / E5CC series, Xiamen Yudian AI series, and RKC CB / CD series.

[0049] After the user sets the target temperature on the host computer, the target temperature is the temperature that the user requires to be output by the air distributor. The host computer software can be Siemens (WinCC), Schneider (EcoStruxure), Rockwell (FactoryTalk), KingView (KingView), ForceControl, etc. The AC controller (2) transmits the digital target temperature setting value to the temperature controller (4) through the 8 / D2 communication interface (such as RS485) using the Modbus-TCP protocol.

[0050] The temperature sensor (7) is positioned 5D (where D is the diameter of the heating coil (5)) above the heating coil (5) to ensure that the detection point is in a sufficiently heat exchange area. The temperature sensor (7) detects the medium temperature in real time through the NTC1 thermistor network, and its resistance change is converted into a digital signal by the Σ-Δ ADC built into the AC controller (2). The AC controller (2) transmits this digital signal representing the real-time medium temperature to the temperature controller (4) through the aforementioned interface and protocol.

[0051] The PWM module of the temperature controller (4) obtains the required plug (1), i.e., the target opening degree of the valve (e.g., 50%), through the first PID module based on the received digital signal of the set target temperature and the real-time medium temperature. After converting the digital signal of the target valve opening degree into an analog signal through the DAC module, it outputs it to the AC controller (2) through the 10 / O 0-10V interface. The AC controller (2) converts the 0-10V signal received from the temperature controller (4) into a digital opening command (e.g., 5V→50%) through the ADC module and stores it in the comparator register (CCR). The electric actuator (6) monitors the valve position in real time through the incremental encoder installed at the rear of the servo motor and converts the mechanical displacement (rotation or linear motion) into A / B phase digital pulse signals. The PWM module (such as STM32) in the AC controller (2) collects the pulse of the incremental encoder through the timer interrupt of the PWM module of the AC controller (2) with a period of 1ms. The comparator of the PWM module of the AC controller (2) compares the timer count value with the opening instruction in the comparison register (CCR), triggers the level to flip, and sends a 4-20mA valve position control signal of 0-100% opening to the electric actuator (6) according to the comparison result. It controls the GPIO pin to output high and low levels, thereby controlling the motor movement in the electric actuator (6) and thus accurately controlling the opening of the plug (1).

[0052] Among them, the DAC is a hardware module that converts digital codes into analog quantities through a resistor network / switch combination. The ADC module is a hardware module that converts analog signals (such as voltage and current) into digital signals. The incremental encoder consists of light-emitting diodes, grating disks, and photoelectric sensors. When the grating disk rotates, light passes through / blocks periodically, generating A / B pulses (used for direction identification) with a 90° phase difference and Z phase (one reference pulse per revolution). The PID module dynamically adjusts the output control quantity by calculating the deviation (error) between the target value and the actual value in real time, so that the system can quickly and stably reach the set target. The PWM in the AC controller (2) consists of a timer, a comparator, and an output control circuit. The counter increments from 0. When it reaches the CCRx value, the output pin level flips (e.g., high → low). When the counter reaches the ARR value, it is reset and starts counting again. At the same time, the output pin returns to the initial level (e.g., low → high). CCRx is the set pulse width (duty cycle). The timer / counter (CNT) receives the pulse signal transmitted by the encoder. Its value is automatically incremented by 1 for each electrical pulse. Electrical pulse: A sudden change in voltage or current that occurs and then quickly recovers within a very short time. Comparison register (CCR): After the host computer sets the temperature, the temperature controller calculates and converts it into an actuator opening command. The opening command is a series of electrical pulse signals, the values ​​of which are accumulated in the register, similar to a timer, except that this value does not change during the comparison process. Each bit of the two binary numbers, CNT and CCR, is directly connected to the corresponding input port of the digital comparator circuit. When CNT increments to exactly equal the value of CCR, the comparator circuit immediately outputs a valid match signal (a high-level pulse). This match signal is directly sent to the timer's control logic circuit, thereby triggering a level transition on the GPIO pin.

[0053] Meanwhile, the PWM module of the temperature controller (4) generates a temperature compensation coefficient (e.g., PID output -10%~+10%) based on the received temperature setpoint, the digital signal of the real-time medium temperature, and the optional opening degree of the aforementioned plug (1) through the second PID module. After DAC conversion, the compensation coefficient is output to the AC controller (2) through the 10 / 00-10V analog interface. The AC controller (2) reads the 10 / 00-10V analog input through the ADC module and converts it into a control command (e.g., 5V→50% power adjustment), dynamically adjusting the PWM duty cycle of the heating coil (5). The PWM (pulse width modulation) controls the equivalent conduction time of the solid-state relay SSR set at the power output terminal of the heating coil (5) by adjusting the duty cycle (high level time ratio), thereby adjusting the average power of the heating coil (5). The solid-state relay SSR consists of four parts: input control circuit, isolation circuit, switching element, and protection circuit.

[0054] Temperature changes after heating (such as the measured temperature value after the air distributor runs for ten minutes) or updated user-set temperature values ​​will trigger the PID module to run again, and at the same time form a closed-loop control through the 10 / 00-10V analog interface.

[0055] Thus, the air distributor forms a dual-loop hardware control circuit: Inner loop (power loop): AC controller -> PWM -> SSR -> heating coil; Outer loop (temperature loop): Temperature controller -> Sensor -> PID -> Analog output -> AC controller.

[0056] During use, the temperature sensor (7) monitors the air temperature in the cabin in real time and transmits the data to the thermostat (4). When the cabin temperature is higher than the set value, the thermostat (4) sends a signal to the AC controller (2). The AC controller (2) increases the air volume of the air distributor to accelerate airflow and enhance heat dissipation. On the other hand, if the air conditioning system has a cooling capacity adjustment function, the AC controller (2) adjusts the cooling capacity output of the air conditioning unit to match the increased air volume, so as to quickly reduce the cabin temperature. When the cabin temperature is lower than the set value, the control system performs the opposite operation, reduces the air volume of the air distributor, and correspondingly reduces the heating output of the air conditioning unit (if it has a heating function), so as to achieve coordinated control of temperature and air volume and maintain the cabin temperature within a comfortable range.

[0057] The terminal block (3) is equipped with a redundant PE grounding terminal, which triggers the AC controller (2) when a leakage current >30mA is detected. The temperature controller (4) has a built-in over-temperature protection module. When a temperature gradient change rate >5℃ / s is detected, the temperature controller (4) is connected to the AC controller (2) via a hard-wired 9 / I0-10V interface. The AC controller (2) is equipped with an audible and visual alarm, which is activated when the temperature gradient change rate of the temperature sensor >5℃ / s or the leakage current >30mA.

[0058] Connection relationships between components and a list of connection ports: 1. Electric actuator Port definition: 1 PK U (Power / Signal Positive) / 2 GYY (Protective Ground) / 3 BK G0 ​​(Common Return Terminal) / 4 RD G (Control Output / Power) Connection relationships:

[0059] The actuator power supply and control signal are grounded independently (G0 and G are separated) to avoid interference.

[0060] 2. AC controller (core control unit) Power input port:

[0061] Signal and communication ports:

[0062] Temperature detection port:

[0063] 3. Temperature controller (temperature decision unit) Input signal: Connect to AC controller port 6 / D1 (digital signal input, to receive ambient temperature data). Output control: Output signal to heating coil (via AC controller).

[0064] 4. Terminal blocks (power distribution hub)

[0065] 5. Heating coil (execution terminal) Connection relationship: Directly connected to the Ltrl4 interface of the AC controller.

[0066] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible variations and modifications without departing from the spirit and scope of the present invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A marine variable air volume distributor, characterized in that, The air distributor includes: The housing is provided with an air inlet connector for connecting to a cooling duct and an air outlet connector for connecting to a supply duct. A plug, the plug being used to cover the opening of the air inlet connector to limit the amount of gas entering the housing, the plug being disposed in the inner cavity of the housing; An electric actuator, the output shaft of which is connected to the plug via a magnetic coupling, is used to drive the plug to move relative to the air inlet connector in order to control the opening degree of the air inlet connector, and the electric actuator is disposed in the inner cavity; A heating coil is disposed at the bottom of the inner cavity and is used to heat the air in the inner cavity; A temperature sensor is disposed in the middle of the inner cavity near the heating coil, for sensing the temperature in the inner cavity; Thermostat, the thermostat being disposed within the inner cavity; and A controller is disposed in the inner cavity and is connected to the thermostat, the temperature sensor, the electric actuator, and the heating coil, respectively. The temperature sensor is unidirectionally connected to the controller via an 1 / NTC1 GND interface; the temperature controller is bidirectionally connected to the controller; the electric actuator establishes an RS485 bidirectional communication link with the controller's J2 communication interface via a 1PKU / 2 GY Y / 3BK G0 / 4RD G four-core cable; and optionally, the electric actuator is unidirectionally connected to the temperature controller.

2. The marine variable air volume distributor as described in claim 1, characterized in that, The outer shell has a double-layer structure with an insulation layer filling the middle layer.

3. The marine variable air volume distributor as described in claim 1, characterized in that, The electric actuator monitors the valve position in real time via an incremental encoder mounted on the rear end of its servo motor.

4. The marine variable air volume distributor as described in claim 3, characterized in that, The controller includes a PWM module, which includes a timer and a comparator. In the controller, the pulses of the incremental encoder are acquired through the timer interrupt with a period of 1ms. The comparator compares the timer count value with the target opening degree of the plug. Based on the comparison result, a 4-20mA valve position control signal with an opening degree of 0-100% is sent to the electric actuator to control the movement of the motor in the electric actuator, thereby controlling the opening degree of the plug.

5. The marine variable air volume distributor as described in claim 1, characterized in that, The controller includes a PWM module, which adjusts the PWM duty cycle of the heating coil according to the temperature compensation coefficient from the thermostat.

6. The marine variable air volume distributor as described in claim 1, characterized in that, The power output terminal of the heating coil is equipped with a solid-state relay, and the controller is connected to the heating coil through the solid-state relay.

7. The marine variable air volume distributor as described in claim 1, characterized in that, The controller and the temperature sensor are connected via an NTC thermistor signal path.

8. The marine variable air volume distributor as described in claim 1, characterized in that, The temperature sensor is located 5D above the heating coil, where D is the diameter of the heating coil.

9. The marine variable air volume distributor as described in claim 1, characterized in that, The temperature controller is equipped with an over-temperature protection module. The temperature controller is connected to the electric actuator through its 9 / I0-10V interface. The 9 / I0-10V interface is activated when the temperature gradient change rate of the temperature sensor is >5℃ / s.

10. The marine variable air volume distributor as described in claim 1, characterized in that, The controller is equipped with an audible and visual alarm, which is activated when the temperature gradient change rate of the temperature sensor is >5℃ / s or the leakage current is >30mA.

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