A resistance measuring device for natural ventilator

Abstract

The present invention discloses a resistance measuring device for a natural ventilator, and relates to the technical field of air outlet resistance performance measurement. The device includes a fan section, an air volume measurement section, a rectifier section, a pressure measuring section, a natural ventilator and a host computer. A variable frequency fan is arranged inside the fan section. The air volume measurement section includes an air volume measurement component and corresponding sensors connected to the host computer, including realizing the calculation, control and output of the pressure difference-air volume curve and resistance performance parameters of the natural ventilator by the device. The upper cover plates of the air duct of the rectifier section and the pressure measuring section are moved and adjusted according to the height of the air inlet of the ventilator. The soft flow equalizing plate at the inlet of the rectifier section is folded according to the height of the air duct. The present invention can quantitatively measure the resistance performance parameters of natural ventilators of different height specifications, solves the problem of difficulty and high cost in modification of existing air outlet resistance measuring devices when measuring natural ventilators, and helps institutions that need to perform detection to accurately and conveniently measure the resistance performance of natural ventilators, thereby serving product selection and architectural design.

Description

Technical Field

[0001] The invention relates to the technical field of air outlet resistance performance measurement, and in particular to a resistance measurement device for a natural ventilator. Background Art

[0002] As an emerging natural ventilation solution, natural ventilators overcome the defects of traditional openable fans in safety and facade design, and are becoming more and more popular in high-rise public buildings. Natural ventilators are generally installed in the aluminum alloy horizontal frame of the curtain wall. The number and installation location of the ventilators can be freely adjusted through the curtain wall interval to ensure the airflow organization and air quality of the indoor air; natural ventilators have wind pressure resistance, watertightness, airtightness, sound insulation, filtration and other properties, and can be placed in the curtain wall interval without destroying the original facade of the building, ensuring the integrity of the high-rise building design. Natural ventilators have diverse structures, complex forms, and a variety of specifications and sizes. For example, the concealed frame natural ventilator is specially designed for the concealed frame curtain wall. The flatness of its outer surface can be better integrated with the curtain wall without affecting the appearance of the building. The vertically mounted natural ventilator is installed in combination with the vertical beam, and the installation length of a single ventilator is generally the floor height. The duct-preset natural ventilator pre-designs the installation position of the ventilator and the duct connecting the indoor and outdoor air when the curtain wall is designed. The ventilator can be effectively combined with the interior decoration to integrate the ventilator into the indoor environment. The ventilators directly exposed to the outdoors are relatively large, with a height of more than 100mm, and are suitable for scenes that require a large amount of fresh air.

[0003] According to the "Ventilators for Building Doors and Windows" JG / T 233-2017, the ventilation volume per meter of a natural ventilator should be no less than 30m3 under a pressure difference of 10Pa. 3 / h, and the air volume is measured according to the "Air Distributor Performance Test Method" JG / T 20-1999. In order to adapt to different scenes and different facade forms, the structure of natural ventilators is complex and diverse. On the one hand, the pressure difference of 10Pa is a relatively small value. Most of the existing measurement devices for conventional mechanical ventilation outlets have a large design pressure difference and are not suitable for the measurement of natural ventilators; on the other hand, natural ventilators need to be coordinated with the design of building beams, slabs, curtain walls, etc., and the specifications and sizes are diverse, unlike conventional air conditioning outlets, which have relatively standardized sizes. Natural ventilators are generally oblong in shape. The standard measurement width of ventilation volume specified in "Ventilators for Building Doors and Windows" JG / T 233-2017 is 1m, and the air inlet height varies from 50mm to 200mm. When it is necessary to measure the resistance characteristics of a group of ventilators of different heights, the difficulty and cost of modifying the traditional air outlet resistance measurement are very high. All these characteristics make the measurement device for conventional mechanical ventilation outlets unsuitable for the measurement of natural ventilators, and also bring certain challenges to the air volume measurement of natural ventilators. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies and shortcomings of the prior art and to propose a resistance measuring device for a natural ventilator to solve the problem that the design pressure difference and air duct specifications of conventional ventilation measuring devices are not suitable for natural ventilator measurement.

[0005] The resistance measurement device for conventional air outlets is often a fixed-size measuring device that is modified with a reducer and a rectifier duct to match the size of the air outlet being measured. On the one hand, this is because the length and width of conventional air outlets do not have definite values, and it is impossible to build a fixed-size device. On the other hand, the size specifications of conventional air outlets have market-based unified standards, and the measuring device can generally meet the measurement requirements after secondary modification.

[0006] The present invention proposes a resistance measurement device for a natural ventilator, which is characterized in that it can measure the resistance of a natural ventilator of a specified width (such as 1m specified in the standard) and any height without the need for secondary diameter change. The calculation module of the device will calculate the resistance coefficient, opening flow coefficient, and flow reduction coefficient caused by the resistance component of the natural ventilator being measured, and record and generate a pressure difference-air volume performance curve, which is helpful for evaluating the resistance characteristics and ventilation performance of the natural ventilator, thereby guiding the practical application of the natural ventilator.

[0007] The invention discloses a resistance measuring device for a natural ventilator, comprising a fan section, an air volume measuring section, a rectifying section, a pressure measuring section, a natural ventilator to be measured and a host computer.

[0008] The air volume measurement section is connected to the rectifying section with a reducer seal and can be welded; the rectifying section and the pressure measuring section form an integral air duct; the pressure measuring section is connected to the ventilator to be measured with a flange and can be disassembled.

[0009] A variable frequency fan is installed in the fan section, and the air supply volume can be adjusted according to needs.

[0010] The air volume measurement section is used to measure the amount of air supply, and includes an air volume measurement component and a corresponding sensor; the air volume measurement component is a Pitot tube or an orifice flowmeter or a nozzle flowmeter.

[0011] A flow equalizer with uniform gaps is set between the air volume measurement section and the rectification section to promote uniform air flow distribution. To adapt to the change in the height of the air duct, the flow equalizer is made of soft porous material, one end of which is connected to the top of the air duct, and the other end can be folded to the bottom of the air duct close to the air volume measurement section according to the height of the air duct. The distance from the flow equalizer to the natural ventilator to be measured must be greater than 3 times the equivalent diameter of the air duct.

[0012] The function of the rectifying section is to allow the airflow to fully develop in the pipe section to avoid the generation of eddy currents, unstable pressure and other phenomena.

[0013] A static pressure ring is set in the pressure measuring section at a distance of about 1.5 times the equivalent diameter of the air duct from the air inlet of the natural ventilator being measured, that is, a number of static pressure holes are evenly opened on the wall of the air duct and connected in parallel to form a pressure measuring ring. The positive pressure end of the micro differential pressure gauge is connected to the measuring surface where the static pressure ring is located, and the negative pressure end is connected to the atmosphere outside the device.

[0014] The air volume measurement sensor and the micro differential pressure gauge, as well as the frequency conversion controller of the frequency conversion fan, are all connected to the host computer.

[0015] As described above, the present invention provides a method for measuring the air volume of a natural ventilator, which uses the resistance coefficient of the ventilator and the air volume under the rated pressure difference as common indicators for measuring the ventilation performance of the ventilator, thereby making up for the lack of knowledge and acceptance of the ventilator air volume measurement in the market. The device can quantitatively measure the performance parameters of the ventilator under a relatively standard working condition, thereby facilitating the measurement of the actual operation effect of the ventilator. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the structural connection of a resistance measuring device for a natural ventilator according to the present invention;

[0017] Figure 2 The present invention is a schematic diagram of the connection between the host computer and the fan frequency conversion controller, the air volume measurement sensor and the micro differential pressure gauge according to the embodiment of the present invention.

[0018] Tag Number Description

[0019] 1: fan section;

[0020] 2: Air volume measurement section;

[0021] 3: Rectification section;

[0022] 4: Pressure measuring section;

[0023] 5: Natural ventilator. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0025] The present invention provides a resistance measuring device for a natural ventilator (such as the attached Figure 1 shown).

[0026] A resistance measuring device for a natural ventilator comprises a fan section 1, an air volume measuring section 2, a rectifying section 3, a pressure measuring section 4, a natural ventilator 5 and a host machine.

[0027] The fan section 1 is provided with a variable frequency fan which can adjust the air supply volume as required.

[0028] The fan section 1 is connected to the air volume measurement section 2 via a variable diameter seal.

[0029] The air volume measuring section 2 is provided with an air volume measuring component and a corresponding sensor, wherein the air volume measuring component is a Pitot tube, an orifice flowmeter or a nozzle flowmeter.

[0030] A flow equalizing plate is arranged between the air volume measuring section 2 and the rectifying section 3 to promote uniform distribution of air flow and uniform gaps; the distance between the flow equalizing plate and the pressure measuring section 4 is greater than 3 times the equivalent diameter of the air duct; the flow equalizing plate is made of soft porous material and is folded or unfolded according to the change of air duct height, and the folded end is located in the direction close to the air volume measuring section.

[0031] The pressure measuring section 4 is provided with a static pressure ring at a distance of about 1.5 times the equivalent diameter of the air duct from the air inlet of the natural ventilator 5 to be measured, that is, a number of static pressure holes are evenly opened on the wall of the air duct and connected in parallel to form a pressure measuring ring, the positive pressure end of the micro differential pressure gauge is connected to the measuring surface where the static pressure ring is located, and the negative pressure end is connected to the atmosphere outside the measuring device.

[0032] The upper cover of the flat air duct composed of the rectifying section 3 and the pressure measuring section 4 is movable, and the other surfaces are fixedly installed and sealed; the movable cover is equipped with strong magnets and resilient sealing strips around it, and the outside of the air duct is also equipped with a strong magnet corresponding to the magnet position of the movable cover. By moving the position of the magnet according to the height of the air inlet of the ventilator to be measured, the device can realize the measurement of natural ventilators of different height specifications.

[0033] The air volume measurement sensor and the micro-pressure difference sensor and the frequency conversion controller of the frequency conversion fan are connected to the host computer (such as the attached Figure 2 shown) are connected.

[0034] Through the host computer, the air volume value and the air volume control error (such as ±1 to 10%) are set before measurement, the fan frequency of the fan section is controlled according to the set air volume value, and the fan frequency is adjusted according to the air volume value measured by the air volume measurement section. When the set air volume value and the measured air volume value are within the set air volume control error range, the air supply volume of the device reaches a stable level for data recording and analysis. The host computer will record the current air volume value and the corresponding pressure difference, and generate the corresponding pressure difference-flow characteristic curve under different air volumes based on multiple groups of measurement results, and calculate the resistance coefficient, opening flow coefficient and air volume reduction coefficient caused by the resistance component of the natural ventilator under test. The calculation formula is:

[0035]

[0036] Where ξ is the local resistance coefficient of the natural ventilator; P s is the static pressure measurement value, Pa; P v is the dynamic pressure, Pa; P t is the total pressure, Pa; q v is the ventilation volume measured under the same experimental conditions, m 3 / h; A dis the cross-sectional area of ​​the air duct, m 2 ; C d is the opening flow coefficient, λ is the air volume reduction coefficient caused by the resistance component, C ds is the opening flow coefficient when there is a resistance component; C do It is the opening flow coefficient when there is no resistance component.

[0037] In summary, in view of the wide variety of natural ventilators and their various specifications, the present invention proposes a method for measuring the resistance of natural ventilators, which can measure natural ventilators of specified width (such as 1m) and different heights, and can quantitatively measure the performance parameters of natural ventilators under a relatively standard working condition, so as to measure the actual operating effect of natural ventilators. The present invention provides a new method and idea for the performance testing of natural ventilators, which helps institutions or individuals who need to perform testing to accurately and conveniently test the resistance characteristics and ventilation capacity of natural ventilators, thereby serving product selection and architectural design.

Claims

1. A resistance measuring device for a natural ventilator, characterized in that: It includes a fan section (1), an air volume measurement section (2), a rectification section (3), a pressure measurement section (4), a natural ventilator (5) and an upper machine; The fan section (1) is connected to the air volume measurement section (2) via a variable diameter seal; A flow averaging plate is provided between the air volume measurement section (2) and the rectifying section (3) to promote uniform air flow distribution and uniform gaps, and the distance between the flow averaging plate and the pressure measuring section (4) is greater than 3 times the equivalent diameter of the air duct; The air volume measurement section (2) comprises an air volume measurement component and a corresponding sensor; The air volume measuring component is a Pitot tube, an orifice flowmeter or a nozzle flowmeter; The pressure measuring section (4) is provided with a static pressure ring at a distance of about 1.5 times the equivalent diameter of the air duct from the air inlet of the natural ventilator (5), that is, a plurality of static pressure holes are evenly opened on the air duct wall and connected in parallel to form a pressure measuring ring, the positive pressure end of the micro differential pressure gauge is connected to the measuring surface where the static pressure ring is located, and the negative pressure section is connected to the atmosphere outside the device; The cover plate of the flat air duct composed of the rectifying section (3) and the pressure measuring section (4) is movable, and the other surfaces are fixedly installed; The movable cover is provided with strong magnets and resilient sealing strips around it to adapt to the change in the height of the air inlet of the natural ventilator being tested. A strong magnet corresponding to the magnet position of the movable cover is also provided on the outside of the air duct. The position of the magnet is adjusted according to the height of the air inlet of the natural ventilator (5); The fan section (1) is provided with a variable frequency fan which can adjust the air supply volume according to needs; The host computer is connected to the frequency conversion controller of the frequency conversion fan, the air volume measurement sensor and the micro differential pressure gauge; The host computer controls the frequency of the variable frequency fan in the fan section (1) according to the set air volume value, and adjusts the frequency of the variable frequency fan according to the air volume value feedback measured by the air volume measurement section (2); When the air volume setting value and the actual air volume value are within the set error range, the air volume of the device reaches a stable level for data recording and analysis; The host computer will record the current air volume value and the corresponding pressure difference, generate the corresponding pressure difference-air volume performance curve under different air volumes, and calculate the resistance coefficient, opening flow coefficient and air volume reduction coefficient caused by the resistance component of the natural ventilator (5) under test. The calculation formula is: In the formula, is the local resistance coefficient of the natural ventilator; P s is the static pressure measurement, Pa; P v is the dynamic pressure, Pa; P t is the total pressure, Pa; q v is the ventilation volume measured under the same experimental conditions, m 3 / h; A d is the cross-sectional area of ​​the air duct, m 2 ; C d is the opening flow coefficient, C ds Indicates the opening flow coefficient when there is a resistance component, C do It indicates the opening flow coefficient when there is no resistance component; is the wind volume reduction factor caused by the resistance components.

2. A resistance measuring device for a natural ventilator as claimed in claim 1, characterized in that: The flow equalizing plate is made of soft porous material and is folded or unfolded according to the change of the air duct height, and the folded end is located in the direction close to the air volume measurement section.

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