The application of constant air volume valve in the fresh air system

The application of the constant air volume valve in the fresh air system is very important, why do you say so?

From the current market application, the air conditioning method of fan coil unit and fresh air system is still more common, especially in the hotel guest room, most office buildings and office buildings adopt this method. The usual practice is to set up each floorSchmaibo fresh air system fresh air unitThe corridor is laid with new air dry pipes, and dozens of branch pipes are connected to each room from the main pipe. It's like a big tree branching out from its trunk.

Taking hotel rooms as an example, the fresh air volume of each room is generally 100 m3 h, how to achieve the same air volume of each branch pipe? Generally speaking, designers often add an air volume control valve to the new air branch pipe, expecting to complete the air volume distribution through later commissioning.

Due toFresh air systemIn general, the main pipe is long, the branch pipe is short, and the adjustment of the air volume control valve is not intuitive, and the adjustment accuracy is not ideal, and the fresh air volume of each room is only 100 m3 h, and the air volume is very small, so the debugging is almost impossible to complete. The construction unit can only measure the total air supply volume of the new air dry pipe to ensure that each air supply branch pipe has a sense of wind.

In order to ensure that the fresh air volume sent to each room can reach the design value, and there is no need for the construction unit to go to the balance of one room after another, we only need to add a fixed air volume valve on each fresh air branch pipe, and the above problems will be solved.

Presumably based on the name:

1. Air volume valve. Obimori is definitely used for ventilation ducts.

2. Constant air volume. Stupid Feng Mu maintains a constant air volume through the base car valve, which can not be large or small. It should be achieved by changing the passing area of the valve inlet and outlet.

Generally speaking, it is to maintain a certain size of air volume through the valve to meet the needs of the work, estimation and hydraulic system.

The relief valve is about the same!

For a good air conditioning system design, its exhaust system must be reasonable, and this is often not taken seriously. In civil buildings, especially in high-rise buildings, the airtightness of the envelope structure is very good, and only a small air volume is needed to maintain the positive pressure value of the room. About 85 90% of the fresh air volume must be discharged outside through an organized exhaust air, so as to ensure the balance of the air volume of supply and exhaust, otherwise no amount of fresh air volume can be sent into the room.

In civil buildings, exhaust air is generally discharged outdoors through auxiliary rooms such as toilets and boiling water rooms. In addition, sometimes an exhaust system should be added to ensure the balance of supply and exhaust. For toilet exhaust, it is common practice to install it in each bathroom.

One or two toilet ventilators, interlocked with the exhaust fan on the exhaust shaft. We know that the fresh air system in a high-rise building should be operated all year round, and the corresponding exhaust air system should also be operated all year round. In other words, the person who uses the toilet cannot control the opening of the toilet ventilator, and there is no need for a bathroom ventilator.

Moreover, the operation of an exhaust system with dozens of small fans is difficult to match and uneconomical. The noise of the toilet ventilator with an exhaust air volume of 400m3 h is about 40db, which makes the toilet lose its tranquility. The large number of restroom ventilators also brings a lot of trouble to maintenance.

In order to solve this problem, we can cancel the toilet ventilator, add a constant air volume valve on each branch pipe of the exhaust shaft, and set up an exhaust fan at the top of the shaft. Such an exhaust system 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 bathroom can be very quiet.

The fixed air volume valve is an automatic mechanical mechanism, which does not need to let or register external power, and can be changed by adding an electric actuator to change the flow rate setting through remote control signal. The constant air volume valve can be applied in the air supply and exhaust system, the working temperature is generally 10 50, and the pressure difference range is 50 1000pa, that is, the pressure difference between the front and back valves of at least 50pa should be applied, otherwise the constant air volume valve can not work. This should be noted, because the air pressure value of the fresh air unit of the fresh air system is generally not large.

The constant air volume valve is not limited by the position when it is installed, but the valve shaft should be horizontal, and it is generally required to have a straight inlet air duct with a long side and a straight outlet air duct with a double distance.

The constant air volume valve has high control accuracy, there is an external pointer to display the flow scale, the adjustment accuracy is about 4%, the flow limiting mechanism does not need to be maintained, and the fixed air volume valve is rectangular, circular, thermal insulation and silencing type can be selected for matching with the system. Just as the balance valve is more and more used by the majority of designers in the air conditioning water system, the constant air volume valve will also be widely used in the air supply and exhaust system due to its precise adjustment and automatic balancing characteristics.

The constant air volume valve is a mechanical self-powered device, which is suitable for ventilation and air conditioning systems that require constant air volume. The airflow control of the constant air volume valve does not require external power, and it relies on the air flow force in the air duct to locate the position of the control valve, so as to maintain the airflow at a pre-set flow rate throughout the pressure difference range.

One is to sense the air flow through the air duct through the silicone airbag in the balancer, and automatically contract and expand according to different static pressures to achieve constant air volume. When the air static pressure at the inlet and outlet is the lowest, the airbag is in a state of contraction. When the static pressure at the air inlet and outlet increases, the airbag begins to expand, thereby reducing the void around the airbag.

Keep the flow constant within a certain range of wind pressure.

The other type is a mechanical self-powered device, which relies on the pressure of the air flow in the air duct to locate the position of the control valve, so as to maintain the air flow at a pre-set flow rate within a certain pressure difference range. It does not require external power and can be changed by means of an electric actuator via a remote control signal.

In the all-air system, due to the influence of building conditions, the resistance between the branches is definitely uneven, and the three-way control valve or the split multi-leaf control valve is generally used to complete the air volume distribution. In order to ensure that the air volume on the important room or main branch pipe is not too large or too small, and the blindness of the reduction of the ruler is less than that of the debugging, the air volume valve can be appropriately set to replace the three-way control valve or the multi-base hand leaf control valve.

In the variable air volume air conditioning system, the variable air volume mode is generally used in the outer area, and the constant air volume mode is used in the inner area.