The 'face' of clean rooms and the 'inside' of environmental control
Hello colleagues, fathers of the first party. I am a veteran who has been working in the cleanroom industry for over a decade.
In this profession, I have seen too many scenes like this:
The boss pointed at the cleanliness testing reports of tens of thousands and hundreds of levels, feeling that this is all about strength. But once I walked into the computer room and saw the air conditioning system that was set up roughly and not maintained all year round, I knew that the car was not far from the accident.
Especially in recent years, the freeze-drying process of biopharmaceuticals, the photolithography area of semiconductors, and even the filling room of high-end cosmetics have reached an "abnormal" level of demanding environmental temperature and humidity. A temperature difference of ± 0.5 ℃ and a humidity fluctuation of ± 3% are no longer numbers in textbooks, but are directly written as life and death lines in batch records.
Today, let's not talk about air vents or color steel plates, but about the "heart" of clean rooms - environmental protection systems. With the technical information on the H-series microcomputer controlled constant temperature and humidity variable frequency unit at hand, I would like to tear apart those high-end parameter tables and talk about the "underlying logic" that truly determines your production line yield.
Why is your cleanroom always in a 'sub healthy' state?
Many operation and maintenance brothers have complained to me, 'This unit is too delicate, it either dies from cold or heat, and the humidity is jumping like crazy.'
Actually, most of the time it's not the device that's not working, it's a problem with your control logic.
Give a real case. Last year, I went to do an audit at a pharmaceutical company that produces innovative drugs. Their QC laboratory has been consistently experiencing OOS (Out of Specification) recently. Although the air conditioning is on and the fresh air has been replaced, the constant temperature and humidity machine is like an exhaust fan, with humidity soaring to 70% in summer and drying up to 20% in winter.
I asked them to open the electrical control cabinet and smiled at the sight. These people keep the "manual/automatic" switch in the manual position all year round for the sake of convenience, and even call it "easy to adjust". This is not convenient, it's just a joke about the stability of the product.
In clean rooms, especially in areas involving GMP compliance, 'rule by man' is the biggest risk. Your hand speed can never keep up with the changes in room heat load. Relying on people to monitor and tighten valves, that was the gameplay of the last century.
This brings us to the first core we are going to talk about today: the game between dual control systems and seasonal strategies.
The "Left and Right Battle" and "Four Seasons Art of War" of the H series
Many people only look at the compressors and humidifiers of the H series unit, which is called buying back pearls. The soul of this system lies in its microcomputer self-control logic.
First move: Dual system redundancy, reject the panic of "single point of failure".
The information mentions a dual control system. This is particularly important in semiconductor factories. Imagine your Fab factory is in its peak production period when the main control board suddenly experiences a blowout. If there is no redundancy, the temperature and humidity of the entire line may lose control, and tens of millions of wafers may be instantly scrapped. The dual control design of the H series is not only for backup, but also a "hot backup" mindset. Even if there are millisecond level fluctuations in the main system, the backup system can seamlessly take over. For medical device and pharmaceutical companies, this is the strongest confidence in verification documents - sustained stability.
Second move: Adapt to the season, don't use brute force to fight against nature anymore.
I want to criticize a phenomenon here: many factories only use one set of PID parameters throughout the year. In summer, the outdoor temperature is 35 ℃, and in winter, the outdoor temperature is -5 ℃. Do you expect the same logic to stabilize the indoor temperature at 22 ℃? This is not scientific.
The 'seasonal operation strategy' mentioned in the H series is crucial.
Summer mode: The focus is on dehumidification. At this point, we cannot rely solely on cooling. We need to make good use of frequency conversion technology to enable the compressor to efficiently dehumidify with low energy consumption. Many factories have high humidity in summer because the refrigeration unit is turned on too hard, resulting in a low dew point, and then they work hard to humidify, which is a typical "left and right battle" and wastes electricity costs.
Winter mode: The focus is on humidification and insulation. The north is dry, and electrode or infrared humidification should keep up; The balance between heating and dehumidification in the humid and cold south is another discipline.
Transition season: This is the most easily overlooked golden period. Making good use of outdoor fresh air and using enthalpy control for free cooling is the energy-saving task that senior engineers should do.
The transformation from "firefighter" to "operation and maintenance expert"
Let's go back to the case of the QC laboratory. After taking over, I did three things for everyone's reference:
Force switch back to automatic: lock the "manual/automatic" switch in the automatic position. Tell the operators that this is not depriving them of their power, but rather shielding them from the risk of human error. Machines understand calculus better than humans and believe in algorithms.
Sensor calibration: The data emphasizes the instrument calibration cycle. The pressure sensor of that pharmaceutical company has not been calibrated for two years, and the data fed back to the PLC itself is wrong. No matter how hard the actuator tries, it is also wrong. I request that they immediately shut down the machine and perform third-party calibration on the temperature, humidity, and pressure sensors. This is the source of the data, if the source is dirty, the entire system will be blind.
Implement the "look, listen, touch, smell" inspection method: Don't underestimate these four words.
Look: Look at the bubbles in the sight glass, look at the discharge of condensed water.
Listen: Listen for any liquid hammer sound from the compressor and any abnormal noise from the fan.
Touch: Touch the pressure difference before and after the filter to determine the blockage.
Smell: Smell for any burnt or chemical odor of refrigerant leakage.
This set is based on the most traditional experience of HVAC, combined with the H series intelligent alarm system, allowing operation and maintenance personnel to transform from passive "firefighting" to active "prevention".
One month later, their temperature and humidity record curve turned into a smooth straight line. This is the power of professionalism.
New challenges of new energy and modern agriculture
In addition to traditional medicine and electronics, the environmental requirements of new energy batteries and modern agriculture (tissue culture rooms) are becoming increasingly bizarre.
In the new energy injection workshop, low humidity requirements are essential and usually need to be controlled below 1% RH. The dehumidification capacity and airtightness of this unit are extreme challenges. The frequency conversion regulation of the H series shows its advantages here, as it can maintain extremely low moisture content through fine-tuning, without frequent start stop causing temperature and pressure fluctuations.
In modern agricultural plant factories, although cleanliness requirements are not high, there are extremely high demands for coupled control of light, CO2 concentration, and temperature and humidity. The logic here is more complex, not only in terms of temperature and humidity, but also in terms of plant growth models. At this point, the openness of the communication protocol of the unit becomes very important. Whether it can be connected to the central SCADA system to achieve linkage control determines the level of intelligence of this plant factory.
Respect professionalism and reject 'almost'
After working in engineering for so many years, the most frightening thing I'm afraid of hearing is: "It's almost enough
In the clean room, there is never a 'similar'. 22 ℃ and 22.5 ℃ are irrelevant to ordinary people, but there is a huge difference in the growth rate of microorganisms in C-level/D-level areas and the lithography accuracy of chips.
The H-series microcomputer controlled constant temperature and humidity variable frequency unit is not just a machine, it represents a refined management mindset. From the pre startup inspection process, to the regular maintenance items, and then to the detailed calibration schedule, behind every page of the paper is the goal of making the temperature and humidity curve smooth and stable enough.
Dear colleagues, whether you are the owner or the construction party, please remember that the highest level of a clean room is not spotless, but "calm and composed". When you no longer worry about temperature and humidity fluctuations, and when you look at the straight lines on the monitoring screen with a calm smile, you truly understand this technical document and the essence of clean room operation and maintenance.