67 results about "Constant air volume" patented technology

Provided is an air-conditioning indoor unit. The air-conditioning indoor unit includes a plurality of centrifugal wind wheels, a motor drivingly connected to the plurality of centrifugal wind wheels, an electric control box disposed in an axial direction of the plurality of centrifugal wind wheels, and an evaporator disposed in a radial direction of the plurality of centrifugal wind wheels and obliquely disposed relative to a height direction of the air-conditioning indoor unit. By providing the plurality of centrifugal wind wheels and driving the plurality of centrifugal wind wheels by a same motor, when a size of the air-conditioning indoor unit is large, a constant air volume may be outputted. The electric control box is located in the axial direction of the centrifugal wind wheel and far away from the evaporator, to prevent the electric control box from being splashed by condensed water. In addition, since there is a large space when the centrifugal wind wheel is provided, the electric control box is located in the axial direction of the centrifugal wind wheel to more facilitate an arrangement of the electric control box. The evaporator is disposed obliquely relative to the air-conditioning indoor unit. In this way, a thickness of the air-conditioning indoor unit can be reduced, and heat exchange efficiency can be improved.

The invention discloses a constant air volume adjusting device for an air conditioner, and relates to the technical field of air conditioners, the constant air volume adjusting device comprises an air conditioner body, the front surface of the air conditioner body is fixedly connected with a dust baffle, the front surface of the air conditioner body is provided with an air outlet cylinder, and the front surface of the air outlet cylinder is provided with a shielding device; the front face of the shielding device is fixedly connected with an adjusting device and a sealing device. By arranging the shielding device, when the wind blocking blades are wound to a preset degree by the winding roller, the air outlet barrel is completely opened, if the air volume needs to be adjusted, a first motor only needs to be started reversely, the winding roller rotates reversely, a hinged plate is released, and the hinged plate drives the wind blocking blades to unfold while sliding in the shell; therefore, it is ensured that the air conditioner body can achieve maximum air volume output, the situation that the air speed is limited due to the influence of air resistance in a specific application scene is avoided, and the air supply capacity and the overall operation efficiency of equipment are improved.

The application belongs to the technical field of heating, ventilation and air conditioning, and particularly relates to a high-strength constant air volume composite air pipe system suitable for a power control room, which comprises a metal inner lining layer, a peripheral reinforcing layer and a gradient thermal expansion transition layer between the two, a sliding interface is embedded in the transition layer or the interface, the transition layer is composed of a high-molecular elastic matrix and radially non-uniformly distributed reinforcing fibers, a linear gradient transition of a thermal expansion coefficient is realized, the sliding interface contains arrayed friction-reducing microbeads, axial displacement compensation is allowed, the system is also integrated with a constant air volume control assembly to guarantee air volume accuracy, through the above structure, thermal stress concentration is effectively eliminated, cracks are inhibited, and air tightness and control stability are maintained.

The invention relates to a mining self-adaptive constant-air-volume control air supply device without sensor detection, which is characterized by comprising a main machine rear cover (2), a fan rear cover (4), a fan (3), a filter device (110) and a main machine front cover (1) which are sequentially connected together, a vibration motor (6) and an electric control board (8) are arranged on two sides of the fan (3), and the filter device (110) is arranged on the main machine front cover (1). The fan (3), the electric control board (7) and the vibration motor (6) are fixed in an internal space set by the main machine front cover (1) through screws; the LED light guide plate (5) is mounted at the top of the fan (3), and a display control plate (8) is further mounted on the LED light guide plate (5); a battery box cover (15), a lithium battery (16) and a battery box (14) are sequentially mounted at the bottom of the fan (3) downwards; a charging interface is formed in the side surface of the battery box (14); due to the design of high filtration, miniaturization, light weight and portability, the equipment is suitable for being worn by individual protection equipment, and is convenient and practical.

The invention discloses a constant air volume control method and device, air conditioning equipment and a medium, the method is applied to the air conditioning equipment which is provided with a fan and an air swing mechanism at an air outlet, and the method comprises the steps that a mapping relation is established for the current target air volume, the mapping relation represents the relation between the swing angle parameter under the current target air volume and the fan rotating speed; in the operation process of the air swinging mechanism, the current parameter value of the air swinging angle parameter is obtained according to a preset control period; obtaining a target rotating speed corresponding to the current parameter value according to the mapping relation; and adjusting the rotating speed of the fan to the target rotating speed. According to the invention, the technical problem of unstable constant air volume control caused by the operation of the air swinging mechanism at the air outlet of the air conditioning equipment is solved.

The present invention discloses a method for monitoring and controlling the air flow rate of a large-scale blast furnace blower unit, comprising a blower unit, an air supply duct, a blast furnace, a check valve, a flow monitor and an air supply valve. Two air supply temperature monitoring points A and B, two air supply pressure monitoring points C and D, and two air supply differential pressure monitoring points E and F arranged on the flow monitor are arranged on the air supply duct between the check valve and the flow monitor. The present invention is provided with a dual-loop measurement, wherein the measurement signal of one loop is used for air supply flow rate monitoring and constant air volume automatic control operation of the blower unit, and the measurement signal of the other loop is used for air supply flow rate monitoring and signal comparison with the control system. By setting a comparison difference control range, it is ensured that the instantaneous fluctuation amplitude of the air supply flow rate does not exceed 4% of the actual flow rate, which can effectively avoid the occurrence of large fluctuations in the blast furnace air supply and serious impact on production due to various abnormalities or failures of the air supply flow rate measurement circuit, thereby ensuring the stable operation of the blower unit and safe production of the blast furnace.

This invention discloses an automatic fuel feeding control strategy for a biomass circulating fluidized bed boiler, solving the problem of how to automatically control the rational supply of biomass fuel in the furnace to ensure stable boiler operation. This invention uses changes in the oxygen content of the flue gas at the boiler tail end to infer changes in the furnace fuel feed. Under the premise of constant air volume, an increase in oxygen content indicates a decrease in biomass fuel feed, while a decrease in oxygen content indicates an increase in biomass fuel feed. A PID control module is established with the oxygen content of the flue gas at the boiler tail end as the input value. The output value of this PID control module is used to adjust the frequency of the fuel feed screw feeder in the biomass circulating fluidized bed boiler. Furthermore, considering the unstable characteristics of biomass fuel, when the oxygen content in the furnace reaches a limit, the feedforward control mode and the lockout function mode of the PID controller are fully utilized to achieve stable boiler operation.

This application belongs to the field of production control technology, specifically relating to an environmental control system, method, and storage medium for production spaces. It includes an air supply module, an indoor air treatment module, an exhaust module, and a control module. The air supply module provides fresh air to the production space; the indoor air treatment module handles the heat and humidity load of the circulating air within the production space; the exhaust module exhausts air from the production space; and the control module controls the air supply module to operate at a constant airflow, and adjusts the exhaust module's airflow by acquiring the actual supply and exhaust volumes to create a stable negative pressure within the production space. This system effectively solves the application bottlenecks of traditional technologies in special protection scenarios. The dual-system architecture significantly reduces reliance on large ducts and ventilation trenches, adapts to space constraints imposed by thick wall structures, and effectively prevents the leakage of potentially hazardous substances.

The application relates to the technical field of biosafety equipment control, and particularly provides a biosafety cabinet constant air volume intelligent control method and system, aiming to solve the technical problem of error control of an existing scheme under a shielding working condition. To this end, the biosafety cabinet constant air volume intelligent control method comprises the following steps: collecting an operation state signal of a biosafety cabinet; determining a multi-dimensional state feature vector based on the operation state signal; obtaining a working condition judgment result based on the state feature vector; and controlling the biosafety cabinet to maintain a constant working area air volume based on the working condition judgment result. In this way, the shielding working condition of the biosafety cabinet can be accurately identified without adding additional hardware sensors, so that low-cost constant air volume intelligent control is realized.

The present application relates to the technical field of range hood, and discloses a range hood wind speed self-adaptive adjusting method, a plurality of fan currents and a plurality of fan rotating speeds are one-to-one corresponding, in the working process, the range hood works under different fan currents; and the increasing trend of oil fume concentration is judged, and an oil fume concentration increasing threshold is set for the corresponding fan current, in the constant current working process of the fan, when the increasing value of the oil fume concentration relative to the reference oil fume concentration exceeds the oil fume concentration increasing threshold, the fan works under the next larger fan current for constant current. The range hood wind increasing of the present application can be divided into multiple stages, under each stage, the working mode of constant current and constant air volume within a certain range is realized, and the wind increasing model can be intelligently corrected along with the increasing trend of the oil fume concentration, the wind resistance sensitivity is effectively improved, and the smoke exhaust effect can be further improved when the exhaust pressure of the public flue is large and the smoke exhaust is not smooth or the flue pressure suddenly changes.

The present application relates to a kind of multifunctional constant air volume valve, including valve body, the adjusting blade being placed in valve body and the rotary filter drying structure being placed in the position of the inlet end of valve body;When air flow enters the inlet end of valve body, rotary filter drying structure is free circumferential rotation under the action of air flow, and rotary filter drying structure is mixed with the impurity and moisture of air flow and adsorbs its impurity and moisture, and the air flow after purification is discharged to the outlet end of valve body by adjusting blade;Rotary filter drying structure includes annular frame arranged in the inner wall of valve body, the air inlet end surface of annular frame has a plurality of equidistant circumferential distribution rotary guide fan blade, and there is sealed ball auxiliary rotating component between the outer wall of annular frame and the inner wall of valve body.The present application has the following advantages: improve purification quality, reduce the resistance of valve body front end, while avoiding affecting the opening degree of valve body blade, ensure the connection stability when constant air volume valve is used.

The invention discloses a pressure-independent type constant air volume valve and a design method thereof. The pressure-independent type constant air volume valve comprises a valve body of a tubular structure, a valve element shaft which is fixedly installed in the valve body and is concentric with the valve body, and a pre-tightening spring which is arranged on the periphery of the valve element shaft in a sliding and sleeving mode, wherein the end, close to an outlet of the valve body, of the pre-tightening spring is fixedly connected with the valve element shaft, and the pre-tightening force is adjustable. The valve element is installed on the periphery of the valve element shaft in a sliding mode, located on the side, close to an inlet of the valve body, of the pre-tightening spring and extruded by the acting force of fluid to push the pre-tightening spring, and the two baffles are symmetrically arranged relative to the valve element, located on the side, close to an outlet of the valve body, of the valve element and fixedly installed in the valve body. The valve element is of a hemispherical shell structure, and the arc convex face of the valve element faces the inlet of the valve body. According to the pressure-independent constant air volume valve, flow can be kept constant within a wide pressure difference range under the condition that no external source power exists, and the pressure difference range of the pressure-independent constant air volume valve can be adjusted by adjusting the pre-compression amount of the pre-tightening spring.

The utility model relates to an air handling unit which comprises a unit shell, an evaporator is arranged in the unit shell and divides the unit shell into a left part and a right part, a high-static-pressure air supply fan is installed in the unit shell located at the left part, and an air return filter screen is installed in the unit shell located at the left end part. The evaporator is responsible for heating or cooling air, the high-static-pressure air supply fan is responsible for uniformly supplying the heated or cooled air into a room, and the return air filter screen ensures that the air entering the unit is clean, further purifies the air and provides clean air for the evaporator; a constant-air-volume exhaust fan and a sensible heat exchanger on the left part of the unit shell are used for carrying out heat exchange treatment on exhausted air, part of heat or cold is recycled, and the energy utilization efficiency is improved; and the fresh air filter screen and the fresh air fan are responsible for introducing fresh air and carrying out the same heat exchange treatment on the fresh air, so that the indoor air quality is ensured.

The application relates to a constant air volume control method, device and equipment of an air conditioning unit and a computer readable medium. The method comprises the following steps: collecting a first real-time static pressure difference value before and after an evaporator of the air conditioning unit; in the case that the difference between the first real-time static pressure difference value and a first preset reference difference value exceeds a predetermined range, adjusting the real-time rotating speed of a fan of the air conditioning unit until the difference between the first real-time static pressure difference value and the first preset reference difference value is within the predetermined range, and maintaining the current rotating speed for constant air volume output, wherein the first preset reference difference value is set for the evaporator in advance. Through detection of the static pressure difference value before and after the evaporator and closed-loop adjustment of the rotating speed of the fan with the preset reference difference value as the target, the technical problem that the existing constant air volume control scheme cannot realize accurate and stable control of the circulating air volume of the air conditioner is solved.

The invention provides a stepless constant air volume control method and system, electronic equipment and a storage medium, is suitable for an air conditioner, and periodically collects a current power value and a current rotating speed of the air conditioner; determining a first air volume value group according to a preset air pressure value group and the current rotating speed; the preset air pressure value group comprises a plurality of preset air pressure values, and the first air volume value group comprises a first air volume value corresponding to each preset air pressure value; determining a second air volume value group according to a preset air pressure value group and the current power value; the second air volume value group comprises a second air volume value corresponding to each preset air pressure value; determining an actual air pressure value of the air conditioner according to the first air volume value and the second air volume value corresponding to each preset air pressure value, and determining an actual air volume value of the air conditioner according to the actual air pressure value; determining a target rotating speed of the air conditioner according to the actual air pressure value, the current actual air volume value and the target air volume value; and if the target rotating speed is not consistent with the current rotating speed, adjusting the rotating speed of the air conditioner according to the target rotating speed to enable the air volume value output by the air conditioner to approach the target air volume value.

The utility model discloses a constant air volume valve adapting to multiple working conditions, which relates to the technical field of valves, and comprises a valve body, a valve core, a valve core and a valve core, the filter unit is arranged at the air outlet of the valve body and comprises C-shaped guide rails arranged below the inner walls of the two sides of the valve body, hinge rods arranged in the C-shaped guide rails, I-shaped blocks arranged on the C-shaped guide rails, a turnover frame arranged between the hinge rods, a filter screen arranged in the turnover frame and a locking assembly arranged on the surface of the upper end of the filter screen. The utility model has the beneficial effects that the filter screen can be completely disassembled and assembled efficiently and quickly, the opening and closing of the filter screen are time-saving and labor-saving, the use requirements of the filter screen under different environments and different working conditions are met, and the firmness of the filter screen under screw installation and the convenience in disassembly and assembly of a magnetic suction type filter screen are also considered.

This invention discloses an airflow control method, device, storage medium, and air conditioner, belonging to the field of air conditioner control technology. When the air conditioner is in swing mode, this invention obtains the current air outlet area of ​​the air conditioner; determines the air outlet area difference based on the current air outlet area and a preset air outlet area; determines the airflow difference based on the air outlet area difference; and adjusts the fan speed of the air conditioner based on the airflow difference. By determining the airflow difference through the air outlet area difference during the air conditioner's swing process and adjusting the fan speed based on the airflow, the airflow of the air conditioner during the swing process remains constant. This constant airflow ensures stable noise during the air conditioner's vertical swing, improving the user experience. Furthermore, regardless of whether it is cooling or heating mode, the vertical swing angle is twice as large as that of existing air conditioners, improving room temperature uniformity.

The application discloses a kind of based on target speed dynamic compensation blast motor control method and system, it is first to collect the original sampling data of blast motor, and extract out key features such as quadrature-axis current, real-time speed and bus voltage by characteristic decoupling.Then, based on the dynamics correlation of quadrature-axis current and real-time speed, dynamically inverse the real-time aerodynamic flow resistance coefficient of current gas path system.Subsequently, by comparing real-time and calibration flow resistance coefficient to determine resistance deviation ratio, and using the ratio to adaptively correct the reference speed set by user, obtain the compensation target speed to maintain constant air volume.Based on this, closed-loop operation is carried out in combination with speed deviation, and bus voltage feedforward compensation and space vector modulation are introduced to generate control signals for driving inverters.In this way, the influence of filter aging or damper switching on air duct resistance fluctuation can be effectively eliminated, and precise control of constant air volume of blast motor under variable load conditions can be realized.

The utility model discloses an integrated constant air volume pressure difference controller, including body mechanism and setting in body mechanism one side, through the way of clamping the communication cable close to the wiring terminal, reduce the cable body swing amplitude, guarantee the location mechanism of close degree of connection, the location mechanism includes the screw rod of screwing on the one side symmetry of casing and set, complete the clamping limit of cable body, finally will each compression ring respectively wear into the outside of limit rod bottom end, rotate compression ring and make it rise to push gasket fully extrude screw rod bottom's position, after fixing the height of each limit rod, clamping installation back seal plate, in the long time's use process, when communication cable shakes under external force, because the part of cable body close to the wiring terminal is pressed and clamped, its shaking degree will reduce greatly, thereby effectively reduce the situation that the communication cable is loose at the wiring terminal connection place due to the cable body shaking, guarantee the stability of communication.

The invention discloses a constant air volume control method and device of a fan, air conditioning equipment and a medium. The method comprises the steps that the current target air volume and the current actual rotating speed of the fan are obtained; the current target air volume and the current actual rotating speed are input into a pre-established relation model to obtain target characteristic values of characteristic parameters of the draught fan, and the relation model represents the mapping relation between the rotating speed of the draught fan and the characteristic parameters under different target air volumes; obtaining a current characteristic value of the characteristic parameters of the fan, and determining a three-phase control voltage for the fan according to the current characteristic value and the target characteristic value; and outputting the three-phase control voltage to the fan so as to adjust the characteristic parameters of the fan. According to the invention, the technical problem of low constant air volume control precision in the prior art is solved.

The utility model discloses a fully-closed air volume control valve for a ventilating duct. Relates to the technical field of ventilation pipelines, and adopts a valve body, a first valve plate and a filter device, and a transmission case is arranged on one side of the valve body. The driving motor is started, the driving motor drives the first rotating rod to rotate, the first rotating rod drives the main gear and the first valve plate to rotate at the same time, the main gear drives the driven gear to rotate, the driven gear drives the second rotating rod to rotate at the same time, and the second rotating rod drives the second valve plate to rotate until the section of the valve body is closed. A first sealing plate arranged at the lower end of the second valve plate on the upper portion is tightly attached to a second sealing plate arranged at the upper end of the first valve plate, a second sealing plate arranged at the upper end of the second valve plate on the lower portion is tightly attached to a first sealing plate arranged at the lower end of the first valve plate, and therefore air is prevented from passing through the gap. And therefore, the sealing performance of the constant air volume control valve during use is ensured.

The invention belongs to the field of air valves, and discloses a quantitative air valve with an air volume control structure, which comprises a valve body, a self-cleaning mechanism penetrates through a shell, the inner side of the valve body is rotatably connected with a shaft column, the outer side of the shaft column is fixedly provided with a supporting seat, the shaft column penetrates through the top of the valve body and is connected with a connecting rod, and the connecting rod is connected with the air volume control structure. One side of the connecting rod is connected with a spring piece through a steel bar, one end of the spring piece is fixed to the top of the valve body, the top of the valve body is rotationally connected with a second adjusting shaft, the second adjusting shaft penetrates through the valve body, and an arc-shaped supporting plate and an adjusting plate are fixed to the outer side of the second adjusting shaft; an electric rotating mechanism is fixed to the top of the shell. According to the quantitative air valve with the air volume control structure, when the air speed is small, the spring piece plays a main role, when the air speed is large, the air bag plays a main role, through linkage of the air bag adjusting assembly and the elastic adjusting assembly, the defects of the air bag adjusting assembly and the elastic adjusting assembly can be avoided, and the advantages of the air bag adjusting assembly and the elastic adjusting assembly are enlarged.

The invention relates to the technical field of motor control, and discloses a multifunctional programmable motor control method and device and computer equipment, and the method comprises the steps: receiving a parameter message sent by an upper computer, and analyzing an operation mode parameter and a programmable motor application parameter in the parameter message; calling a corresponding motor operation mode based on the operation mode parameter, and calculating a target value based on the corresponding programmable motor application parameter in the operation mode; according to the method, free switching between a constant air volume control mode and other control modes is achieved, control application parameters of different modes are called to support motor operation, programmable setting parameters are further achieved, and the method is suitable for large-scale popularization and application. The problem that the motor control mode is single due to the fact that motor programming cannot be achieved is solved.

The utility model discloses an integrated turn-off type pressure independent type constant air volume butterfly valve, and relates to the technical field of laboratory ventilation, the integrated turn-off type pressure independent type constant air volume butterfly valve comprises a breather pipe, and the breather pipe is provided with a pressure independent type constant air volume butterfly valve body; the pressure-independent type constant air volume butterfly valve body comprises a mounting shell arranged on a breather pipe, an actuator is arranged on the mounting shell, fixing shells are arranged on the front side and the rear side of the inner wall of the breather pipe, the fixing shells on the two sides are connected with a rotating shaft, the rotating shaft is connected with the actuator, and the actuator drives the rotating shaft to rotate. The butterfly plate rotates by 90 degrees in the ventilation pipe, so that the two sides can be attached to the sealing rings on the baffles respectively, rapid sealing of the ventilation pipe can be achieved, the butterfly valve design is adopted, opening and closing are rapid, airflow can be rapidly isolated when needed, and harmful gas or microorganisms can be effectively prevented from diffusing when animal houses are killed.

A method and for controlling a draught fan including: obtaining an actual rotating speed, an actual power, and a target air volume of the draught fan, obtaining a target power corresponding to the target air volume according to the actual rotating speed and the target air volume, obtaining, in response to a power difference value between the actual power and the target power being not within an initial difference value range, a control duration and a rotating speed step size corresponding to the power difference value, and adjusting the actual rotating speed according to the rotating speed step size after the control duration. A dynamic adjustment of the air volume of the draught fan is achieved, and a constant air volume control of the draught fan with low cost, high control accuracy, fast adjustment speed and good stability is achieved.

The invention discloses an air volume control valve and a driving method, and relates to the technical field of fluid control valves, the air volume control valve comprises a valve cylinder, a valve element, a transmission mechanism, a valve element fixing mechanism and a valve element driving mechanism, the valve cylinder comprises straight pipe sections at the two ends, a contraction section located in the middle and a cylindrical throat part, and the valve element is provided with a pressure-independent regulator. According to the control valve, a diffusion section is omitted, and the length of the valve cylinder is greatly shortened; the valve element is arranged in the valve cylinder, the crank sliding block mechanism is adopted in a matched mode to move the position of the valve element, the sectional area of the valve element and the sectional area of the valve cylinder are changed, adjustment of the set air volume is achieved, after the valve element moves to the set air volume position, the fixed shaft and the movable shaft do not generate relative displacement any more, and constant air volume is achieved through the pressure irrelevant adjuster of the valve element. The deviation of air volume constant adjustment is within + / -5%, and relevant standards and actual requirements are met.

A motor control apparatus may relate to a motor control apparatus, an air conditioning system, and a constant airflow control method of a fan motor control apparatus of an indoor unit, in which table information on an airflow command value corresponding to a reception pattern or type of a signal is prestored to determine a corresponding airflow command value from the table information according to a result of receiving the signal from a central control apparatus so as to control an operation of a fan motor.

The application discloses a multi-cold-source heat recovery constant air volume constant temperature and constant humidity fresh air machine, which comprises a fresh air system, an exhaust air system, a total heat exchanger, a first compressor system loop, a second compressor system loop and an air-water heat exchanger. The air-water heat exchanger is used for being automatically opened when the humidity of the fresh air entering the room is greater than the set humidity, so that external cooling water is introduced to condense and dehumidify the passing fresh air. The first compressor system loop is used for further condensing and dehumidifying the passing fresh air through a first evaporator. The second compressor system loop is used for heating the fresh air with lower temperature after twice condensation and cooling through an air-cooled heat recovery condenser, and further reducing the temperature of the water inlet through the heat exchange between a second evaporator and the water inlet of the air-water heat exchanger to improve the condensing and dehumidifying effect. The system can effectively guarantee the dehumidifying effect, so that the dehumidifying effect is not affected by the temperature change of the external cooling water, and the constant humidity purpose is achieved.

The utility model is suitable for the technical field of air valve adjustment, and provides an air valve constant air volume adjusting device which comprises a valve body, a driving motor is installed at the top end of the valve body, a rotating rod is rotationally connected in the valve body, and the end of an output shaft of the driving motor is connected with the end of the rotating rod. The driving motor is used for driving the rotating rod to rotate, a dustproof mechanism is installed in the valve body, the dustproof mechanism is used for blocking dust in air circulation, and the dustproof mechanism comprises a dustproof net and a strip-shaped hole. By arranging the dustproof mechanism, impurities and dust in air circulation are attached to the dustproof net, clean air circulates to a designated area, and after long-time use, the dustproof net can be drawn out to be cleaned, so that the effect of blocking the dust in the air is achieved, the air quality in the area is improved, and the service life of the air conditioner is prolonged. And the condition that dust is attached to the blades is avoided.

The invention relates to a control method of a ducted air conditioner, a computer storage medium and the ducted air conditioner. The control method comprises the steps that the mapping relation between the air outlet area S and the air volume q of the duct type air conditioner is preset; when the duct type air conditioner runs, the actual motor rotating speed V ', the actual coil pipe middle temperature T1 'and the actual air return pipe temperature T2' of the duct type air conditioner are obtained; based on the actual motor rotating speed V ', the actual coil pipe middle temperature T1' and the actual air return pipe temperature T2 ', the actual air outlet area S' of the duct type air conditioner is determined; based on the actual air outlet area S'and the mapping relation, the actual air volume q 'of the duct type air conditioner is determined; comparing the actual air volume q'with the corresponding standard air volume Q; and on the basis of the comparison result, the actual motor rotating speed V'is adjusted until the adjusted actual air volume q 'conforms to the standard air volume Q. By establishing the mapping relation between the air outlet area S and the air volume q, the constant air volume adjusting precision is improved.