What are the reasons for the insufficient air supply after the operation of the air conditioning system in the medical clean room?
Release time:2019-09-26 source:
The reasons for insufficient air supply after operation of air conditioning system in medical clean room are as follows:
1. The total air volume of air conditioning units is insufficient (exhaust fan units)
The insufficiency of total air volume of air conditioning units is a common problem in project implementation. The insufficiency of total air volume of units will inevitably affect the air volume of the air outlet at the end of the room and the number of air exchange. The insufficient number of air exchange in the room will not reach the purification level of the room and at the same time can not meet the requirements of some functional rooms. The workshop is deadly. For debugging, the test of total air volume is the premise of other testing work, and it is an indispensable and important link.
The insufficiency of total air volume of air conditioning units is usually caused by the following common problems: when the external residual pressure is insufficient, the reasons are analyzed:
1. Check the motor circuit of the air-conditioning unit to check whether the output voltage and current meet the requirements and whether there is any abnormality.
2. Check the installation status of the fan, and there is no loosening of the conveyor belt. 3. The performance of the fan itself is insufficient, or the selection of the fan is too small.
Reasons analysis when external pressure is satisfied:
1. The system pipeline is not smooth. (In the process of construction and installation, the film paper at the air duct connection has not been torn off, etc.)
2. The design of pipeline size is on the small side, or the resistance of actual system is on the large side.
3. If the constant air volume system, check whether the valve setting scale is consistent with the design value.
2. Insufficient room ventilation
The number of ventilation is determined by the total air supply and the volume of the room.
Under the condition of constant room volume, the air supply rate determines the number of ventilation in the room. The number of ventilation determines the indoor air quality. The common types of air conditioning system can be roughly divided into three types: conventional system (manual valve control), constant air volume CAV system (including double-position constant air volume DAV) and variable air volume VAV system. In view of the above-mentioned type of system analysis, some common cases of insufficient air flow in tuyeres (total air flow of units meets the design value) are analyzed.
1. Conventional system (manual valve control) makes a thorough test of the whole system. The test data are analyzed and balanced by "peak-cutting and valley-filling" method to ensure that the low-volume tuyere valve is in full open state. The size of air duct is too small or the opening of air outlet and air duct interface is too small, the effective passing area is less than the design requirements.
2. The static pressure of supply air of CAV system (including double-position constant air volume DAV) unit is insufficient, the pressure head of CAC (DAV) valve can't reach the working state. CAV (DAV) can't adjust the air volume because of the internal valve blade being blocked by rivets, external deformation and other reasons (such as damage of air bag, relaxation of internal spring sheet, etc.). Valve can not be adjusted (piezometer installation error, electrical signal access error, valve installation direction installation reverse, etc.)
3. VAV System
Variable air volume (VAV) system is a system type for comfortable area. The air supply volume varies according to the change of indoor load, keeps constant air supply temperature, and automatically adjusts the air supply volume of air conditioning system. VAV valves can be opened or closed according to the temperature sensing signal, which is controlled and regulated by automatic control.
3. The gradient of room pressure difference does not meet the requirements of specifications
IV. Leakage of High Efficiency Filter
High efficiency filters (including return air filters) are generally installed at the end of the room as a filter device, mainly used to capture and filter particles below 0.5 micron. The commonly used end models are H13 and H14. The seal forms are divided into mechanical seal and liquid tank seal. High-efficiency filter is the most critical link of purification safety. If the filter leaks, a large number of polluted particles will enter the clean room, and the purification environment will not be controlled. In order to solve this hidden danger, it is necessary to test the filter leakage. Leak detection of filters can be divided into photometer method and particle counter method. The common problems in the leak detection test of photometer are analyzed and discussed.
The smoke detected by photometer is cold smoke and hot smoke, and the smoking substance is PAO. Leak detection test of filter should be done after the balance of air flow in tuyere is completed. When using the smoke form of cold smoke, sometimes the upstream concentration can not be reached. The general reasons are as follows: the filter smoke outlet adopts a clamp joint (when the joint is stuck, the metal sheet is opened, and smoke enters the filter from around the metal sheet). The resistance of this joint is larger, which leads to the concentration insufficiency.
As a professional project design, system engineering construction, supporting product sales purification engineering enterprise, Edward Purification has professional secondary qualification of purification engineering, strong strength, rich experience, strict to every detail of purification engineering, to ensure the quality of purification operation room, is a trustworthy purification manufacturer for customers. To learn more about the medical purification industry, please pay attention to the Wechat Public No. Aide-188 (Ed Purification and Oxygen Supply)