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Hospitals often use ozone for sterilization, such as operating rooms, wards, medical equipment, etc. How to calculate the size of the ozone machine in different occasions, or design the entire ozone sterilization system, let us share with you the basic principles and application knowledge of ozone sterilization
The corona discharge type ozone generator of CE Environment Technology Co., Ltd uses the principle of electromagnetics, E=U/D (E = F / q, E = KQ / r2), E is the field strength generated by static electricity, When E is greater than the critical value for air to be ionized, the oxygen in the air will be ionized into oxygen atoms. The oxygen atoms are extremely active. The high-voltage discharge stainless steel ozone tube quickly generates ozone with oxygen. The process of sterilization is the decomposition of ozone in space. Oxygen-forming atoms and ozone itself use their oxidizing properties to sterilize.
We need to know that the standard for ozone sterilization is the CT value, C is the ozone concentration, and T is the retention time after the ozone concentration reaches the standard. For example, ozone drinking water sterilization CT=1.6, C=0.4ppm, T=4 minutes. (The concentration of ozone in water is 1ppm=1.0g/m3, and the concentration of ozone in the air is 1ppm=2.14mg/m3)
The hourly decay rate of ozone air is 61% (changes to oxygen)
The working efficiency of the ozone generator is 75%
The volume of the hospital’s space is V cubic meters
The requirement of sterilization ozone concentration is B (ppm or mg/L)
The output of the ozone machine is Y
The concentration B of ozone can be checked by clear standards. If it is to deodorize, keep fresh, reduce microorganisms, bacteria and viruses in the air, it is usually a reference for empirical values.
How to determine the value of V, because the clean space involves ventilation problems and ozone is added to the pipeline through the central air conditioning, the V value usually consists of three parts, namely V=V1+V2+V3, V1 is the size of the clean space, V2 is the volume of the central air-conditioning duct, and V3 is the fresh air volume of the central air-conditioning system
How to determine the size of the fresh air volume V3?
1 Fresh air volume that meets sanitary standards:
Ensure that the amount of fresh air per person per hour in the clean room is not less than 40m3/h, while considering the occurrence of harmful gases.
The amount of fresh air that meets the hygiene standards can be divided into two situations:
1) In the case that no obvious harmful gas occurs in the workshop, according to the "Clean Plant Design Specification", it is ensured that the amount of fresh air supplied to the clean room by the purification workshop is not less than 40m3/ (h-person).
2) For the occurrence of harmful gases in the workshop, the fresh air volume to dilute the harmful gas in the workshop should be calculated according to the allowable concentration of harmful gases contained in the workshop.
2 Compensate the fresh air volume required for indoor exhaust and maintain positive indoor pressure:
The "Code for Design of Clean Workshops" (GB50073-2001) stipulates that the amount of fresh air shall be the larger of the two items meeting sanitary requirements and maintaining positive indoor pressure (while ensuring local exhaust). In order to prevent ambient air (air containing harmful gases) from entering the clean room, interfering with the temperature and humidity of the workshop, and destroying the cleanliness in the workshop, a certain amount of fresh air is required in the air conditioning system to maintain positive pressure in the workshop and workshop. When the air supply and return air system control valves in the system are adjusted to the air supply volume greater than the return air volume of the workshop, the workshop will be in a positive pressure state, and the difference between the supply and return air volume (that is, the amount of fresh air that needs to be supplemented) will pass through the doors and windows. Seepage from places (including the opening of the door). The positive pressure value in the room is exactly equivalent to the resistance when air seeps from the gap. Under normal circumstances, the indoor positive pressure between 5 ~ l0Pa can meet the requirements
3 In order to ensure the air cleanliness level of the air supply:
Calculate and determine the air supply volume according to the heat and humidity load. The amount of fresh air supplied to the clean room.
According to the formula, the size of the clean space sterilization ozone machine is Y=VxB/(1-61%)x75%. When the hourly consumption Y value of ozone is greater than 1 kg, an ozone system is usually used to ensure the continuity and stability of sterilization. Ozone The mixing system includes air compressor, filter, refrigeration dryer, adsorption dryer, gas storage tank, ozone space detector, oxygen machine, ozone generator, exhaust gas processor, etc.
The corona discharge type ozone generator of CE Environment Technology Co., Ltd uses the principle of electromagnetics, E=U/D (E = F / q, E = KQ / r2), E is the field strength generated by static electricity, When E is greater than the critical value for air to be ionized, the oxygen in the air will be ionized into oxygen atoms. The oxygen atoms are extremely active. The high-voltage discharge stainless steel ozone tube quickly generates ozone with oxygen. The process of sterilization is the decomposition of ozone in space. Oxygen-forming atoms and ozone itself use their oxidizing properties to sterilize.
We need to know that the standard for ozone sterilization is the CT value, C is the ozone concentration, and T is the retention time after the ozone concentration reaches the standard. For example, ozone drinking water sterilization CT=1.6, C=0.4ppm, T=4 minutes. (The concentration of ozone in water is 1ppm=1.0g/m3, and the concentration of ozone in the air is 1ppm=2.14mg/m3)
The hourly decay rate of ozone air is 61% (changes to oxygen)
The working efficiency of the ozone generator is 75%
The volume of the hospital’s space is V cubic meters
The requirement of sterilization ozone concentration is B (ppm or mg/L)
The output of the ozone machine is Y
The concentration B of ozone can be checked by clear standards. If it is to deodorize, keep fresh, reduce microorganisms, bacteria and viruses in the air, it is usually a reference for empirical values.
How to determine the value of V, because the clean space involves ventilation problems and ozone is added to the pipeline through the central air conditioning, the V value usually consists of three parts, namely V=V1+V2+V3, V1 is the size of the clean space, V2 is the volume of the central air-conditioning duct, and V3 is the fresh air volume of the central air-conditioning system
How to determine the size of the fresh air volume V3?
1 Fresh air volume that meets sanitary standards:
Ensure that the amount of fresh air per person per hour in the clean room is not less than 40m3/h, while considering the occurrence of harmful gases.
The amount of fresh air that meets the hygiene standards can be divided into two situations:
1) In the case that no obvious harmful gas occurs in the workshop, according to the "Clean Plant Design Specification", it is ensured that the amount of fresh air supplied to the clean room by the purification workshop is not less than 40m3/ (h-person).
2) For the occurrence of harmful gases in the workshop, the fresh air volume to dilute the harmful gas in the workshop should be calculated according to the allowable concentration of harmful gases contained in the workshop.
2 Compensate the fresh air volume required for indoor exhaust and maintain positive indoor pressure:
The "Code for Design of Clean Workshops" (GB50073-2001) stipulates that the amount of fresh air shall be the larger of the two items meeting sanitary requirements and maintaining positive indoor pressure (while ensuring local exhaust). In order to prevent ambient air (air containing harmful gases) from entering the clean room, interfering with the temperature and humidity of the workshop, and destroying the cleanliness in the workshop, a certain amount of fresh air is required in the air conditioning system to maintain positive pressure in the workshop and workshop. When the air supply and return air system control valves in the system are adjusted to the air supply volume greater than the return air volume of the workshop, the workshop will be in a positive pressure state, and the difference between the supply and return air volume (that is, the amount of fresh air that needs to be supplemented) will pass through the doors and windows. Seepage from places (including the opening of the door). The positive pressure value in the room is exactly equivalent to the resistance when air seeps from the gap. Under normal circumstances, the indoor positive pressure between 5 ~ l0Pa can meet the requirements
3 In order to ensure the air cleanliness level of the air supply:
Calculate and determine the air supply volume according to the heat and humidity load. The amount of fresh air supplied to the clean room.
According to the formula, the size of the clean space sterilization ozone machine is Y=VxB/(1-61%)x75%. When the hourly consumption Y value of ozone is greater than 1 kg, an ozone system is usually used to ensure the continuity and stability of sterilization. Ozone The mixing system includes air compressor, filter, refrigeration dryer, adsorption dryer, gas storage tank, ozone space detector, oxygen machine, ozone generator, exhaust gas processor, etc.
