Application of the hottest constant air volume reg

2022-08-23
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The application of constant air volume regulating valve in ventilation and air conditioning system

[Key words] constant air volume valve, exhaust system, VAV air conditioning system

[Abstract] this paper introduces several application methods of constant air volume valve in ventilation and air conditioning system, such as: application in fresh air system, application in exhaust system, application in VAV air conditioning system, application in purification air conditioning system, etc, It also explains that the proper use of constant air volume valve in the project can optimize the system design, which is conducive to the balance of air supply and exhaust, the balance of system air volume, and reduce the workload of commissioning

constant air volume valve is a mechanical self-supporting device, which is suitable for ventilation and air conditioning systems requiring constant air volume. The air volume control of the constant air volume valve does not need additional power. It relies on the air flow force in the air duct to locate the position of the control valve, so as to maintain the air flow at the preset flow within the whole pressure difference range

(I) application in fresh air system

at present, the air conditioning method of fan coil plus fresh air system is still common in China, especially in hotel rooms, which is used in most office buildings and office buildings. The usual practice is to set fresh air units on each floor, lay fresh air main pipes in the walkway, and dozens of branch pipes are connected to each room from the main pipe. Taking hotel rooms as an example, the fresh air volume of each room is generally 100 m3/h. how to make the air volume of each branch consistent? Generally speaking, designers often add an air volume regulating valve on the fresh air branch pipe, hoping to complete the air volume distribution through later commissioning. Generally speaking, the fresh air system has long main pipes and short branch pipes, and the adjustment of air volume regulating valve is not intuitive, and the adjustment accuracy is not ideal. Moreover, the fresh air volume of each guest room is only 100 m3/h, and the air volume is very small, so such debugging is almost impossible. The construction unit can only measure the total air supply volume of the fresh air main pipe to ensure that each air supply branch pipe has a wind sense. In order to ensure that the fresh air volume delivered by each room can reach the design value, and there is no need for the construction unit to go to a room by room balance, we only need to add a constant air volume valve on each fresh air branch, and the above problems can be solved

people living and working in high-rise buildings often worry about the lack of fresh air volume, and designers often feel very aggrieved. Because from the drawing, the value of the fresh air volume standard is not low, but we often ignore a problem, how to ensure the actual effect from the design point of view, and the constant air volume valve in the fresh air system 1. Button box: the application that can more easily manipulate the clamping of high and low jaws is a powerful measure

at present, the constant air volume valve mainly depends on imports, and the price is relatively expensive. The author suggests that it is more suitable to use high-end office buildings in four-star and five-star hotels

(II) application in exhaust system

a good air conditioning system design, its exhaust system must be very reasonable, and this point is often ignored. In civil buildings, especially in high-rise buildings, the air tightness of the enclosure structure is very good, and the positive pressure value of the room can be maintained with less air volume. About 85 ~ 90% of the fresh air volume must be discharged outside through organized exhaust, so as to ensure the balance of air supply and exhaust, otherwise no amount of fresh air can be sent into the room. In civil buildings, the exhaust air is generally discharged outdoors through auxiliary rooms such as toilets and boiling water rooms. In addition, sometimes an additional set of exhaust system should be added to ensure the balance of air supply and exhaust. For toilet exhaust, the usual practice is to set one or two toilet ventilators in each toilet, which are interlocked with the exhaust fan on the exhaust shaft. We know that the fresh air system in high-rise buildings should be operated all year round, and the corresponding exhaust system should also be operated all year round. In other words, people who use the bathroom cannot control the opening of the ventilator in the bathroom, so there is no need to set the ventilator in the bathroom. Moreover, the operation of an exhaust system with dozens of small fans is difficult to match and uneconomical. The ventilator noise of the toilet with an exhaust volume of 400m3/h is about 40dB, which makes the toilet lose its tranquility. A large number of toilet ventilators also bring great trouble to maintenance. In order to solve this problem, we can cancel the ventilator in the toilet, add a constant air volume valve on the branch pipe on each floor of the exhaust shaft, and set an exhaust fan on the top of the shaft. In this way, the exhaust system with a specific surface area of 593 M2 g ⑴ of the obtained material can ensure that the exhaust air volume of each floor is roughly equal, and the system control is simple, the operation is reliable, and the toilet can be very quiet

(III) application in VAV air conditioning system

in VAV air conditioning system, generally, VAV mode is adopted in the outer area and constant air volume mode is adopted in the inner area. In an air supply system with constantly changing air volume and air pressure, the constant air volume design in the inner area is inseparable from the constant air volume valve

(IV) application in purified air conditioning system

it is very important to maintain the positive pressure value of the clean room in the purified air conditioning system. Setting the air volume valve in the exhaust or supply and exhaust system can effectively ensure the positive pressure value of the clean room

the positive pressure of the operating room should be maintained both when the operation is in progress and when it is not in progress. The fresh air volume during the operation is the fresh air volume required to ensure the positive pressure plus the fresh air volume required by personnel. When the operation is not in progress, the fresh air volume is only the fresh air volume required to ensure the positive pressure. Therefore, a double position constant air volume valve should be set on the fresh air pipe

(V) application in the balance of air duct pipeline

in the all air system, due to the influence of building conditions, the resistance between branch pipes is certainly uneven, and generally three-way regulating valve or opposed multi leaf regulating valve is used to complete the air volume distribution. In order to ensure that the air volume on important rooms or main branches is not too large or too small, and reduce the blindness of commissioning, the air volume valve can be appropriately set to replace the three-way regulating valve or the opposed multi leaf regulating valve

(VI) features in the use of constant air volume

the constant air volume valve is an automatic mechanical mechanism, which does not need external power. An additional electric actuator can be added to change the flow setting through remote control signals. The constant air volume valve can be used in both air supply and exhaust systems. The working temperature is generally 10 ~ 50 ℃, and the pressure difference range is 50 ~ 1000Pa, that is, at least 50pA pressure difference is applied behind the valve in front of the valve, otherwise the constant air volume valve cannot work. This should be noted, because the wind pressure value of the fresh air unit of the fresh air system is generally not large. The installation of the constant air volume valve is not limited by the position, but the valve disc shaft should be horizontal. Generally, it is required to have a straight inlet air duct 1.5 times the distance of the long side of the valve with high precision and a straight outlet air duct 0.5 times the distance. Set

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