In the food manufacturing sector, air quality faces serious challenges. Among them, microbial contamination is the key challenge. This is mainly due to the ubiquitous presence of microorganisms such as bacteria, molds and viruses. Not only can they originate from environmental flora, but they can also grow and spread from areas such as employees’ hands and equipment surfaces. Under the right temperature and humidity conditions, microorganisms can quickly multiply and be released into the air, posing a significant threat to food quality and safety.
Odor Problems and Dust in Food Manufacturing
Odor problems are also common in food manufacturing. In the process of food processing, raw materials, processing steps, the use of additives and the disposal of waste, will give rise to a variety of odors.
Dust is also an issue that should not be ignored.
During the crushing, mixing and transportation of raw materials, large quantities of dust can fill the air. This not only affects the quality of the product, but can also be inhaled by the employees, damaging their health.
The Importance of Air Quality
Since food is directly related to people’s health, poor air quality can lead to food spoilage and contamination, which in turn can lead to food safety incidents. Therefore, in order to protect the health of consumers and maintain the reputation of enterprises, the requirements for high quality air in the food manufacturing industry need to be strictly controlled.
Types and Characteristics of Air Filters
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Primary filter
In food manufacturing, primary filters are widely used. Because the primary filter has a large filtration area, high dust capacity, large air volume, low resistance and long service life and other characteristics, so it is used in large quantities.
The filter material is usually high-quality polyester synthetic fiber, and the outer frame is mostly galvanized iron or aluminum alloy, which is convenient for replacement. They can effectively remove larger particles of dust, suspended matter, etc..
They are mainly used at the front end of ventilation systems in food manufacturing plants, such as raw material transportation channels, thus reducing the pressure on subsequent medium- and high-efficiency filtration.
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Medium Efficiency Filters
Medium-effect filters are categorized into bag and plate types. They have the advantages of solid construction, lower risk of breakage and leakage, high dust holding capacity, reusability and easy cleaning.
They can capture particle dust and various suspended matters ranging from 1 to 5 microns and are commonly used in the intermediate filtration of central air conditioning ventilation systems and as the front-end filtration of high-efficiency filters, such as centralized air supply systems in food processing workshops.
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High-Efficiency Filters
High-efficiency filters have a high filtration efficiency and are mainly used to capture particle dust and various suspended matters below 0.5 microns. Their filter elements and shells are well-designed, and the filtration efficiency can reach 99.95%@0.5um (H13), 99.995%@0.5um (H14).
They are suitable for food production areas with extremely high air quality requirements, such as sterile workshops and clean rooms.
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High-Temperature Resistant Filters
High-temperature resistant filters use high-performance and high-quality filter materials, and the outer frames are made of stainless steel or galvanized frames, with strong materials. They have characteristics such as high filtration efficiency, low resistance, and good heat resistance, and can work stably in high-temperature environments.
They are often used in food baking equipment, high-temperature sterilization equipment, etc., and can effectively ensure the air quality during the high-temperature processing of food.
Air Filtration Applications in Production Links
Production Equipment End
At the production equipment end of food manufacturing, air filters play a crucial role. Taking the drying and sterilization of food materials as an example, common high-temperature tunnel ovens cannot operate without high-temperature resistant air filters when sterilizing food materials.
Such filters can ensure that the food materials are not contaminated by unclean air during the drying process, thereby guaranteeing the quality and safety of food. For example, in the production of baked goods, the washed raw materials need to be dried.
At this time, high-temperature resistant air filters can effectively block impurities and microorganisms in the air, providing a pure drying environment for food. In addition, in some special food processing equipment, such as equipment used for sterilization, air filters can ensure the air quality inside the equipment and prevent the influence of external pollution on the sterilization effect, thereby guaranteeing the quality of food.
Production Workshop Environment
In food production workshops, to achieve a dust-free and sterile environment, the rational application of air filters is crucial.
Firstly, it is necessary to install primary filters, medium filters, and high-efficiency filters at the air intake end for multi-stage filtration. Primary filters can intercept larger particles of dust and suspended matters, reducing the burden for subsequent filtration; medium filters further capture smaller particles; high-efficiency filters can remove microscopic particulates to ensure that the air entering the workshop meets certain dust-free and sterile requirements.
For places with extremely high environmental requirements, such as infant food production workshops, such as milk powder factories, the air filtration link should be strictly controlled. At the same time, the design of air flow direction control should be reasonable to make the clean air flow from the clean area to the non-clean area and avoid cross-contamination.
In addition, according to the characteristics and requirements of the workshop, an appropriate air circulation and mixing scheme should be set up, and the cleanliness within the workshop should be maintained by reasonably adjusting the air supply and return outlets, air supply and return speeds, etc.
Waste Gas Emission Treatment
During the production process of food factories, such as baking, frying, roasting, fermentation, and other processes, high-concentration waste gas will be generated. If these waste gases are directly discharged outdoors, they will seriously pollute the environment.
At this time, air filters play a key role in waste gas emission treatment. By installing appropriate air filters at the waste gas emission end, harmful substances and particulates in the waste gas can be effectively filtered to meet the emission standards.
For example, in fried food factories, the waste gas generated may contain a large amount of cooking fumes and odors. After treatment by air filters, the emissions of cooking fumes and odors can be significantly reduced, protecting the surrounding environment.
Different types of food factories need to select the appropriate filters according to their production characteristics and waste gas composition and regularly maintain and replace them to ensure the normal operation and efficient filtration effect of the filters.
Maintenance and Replacement of Air Filters
Cleaning Methods of Air Filters
The cleaning methods of air filters vary depending on the type of filter and the degree of dirtiness. For primary and medium filters that are not too dirty on the surface, they can be taken outdoors and blown and washed on both sides with clean compressed air until no dust particles are visible under the light.
If the filter surface is very dirty, primary and medium filters can be placed in the cleaning tank, add an appropriate amount of detergent for rinsing, then rinse with clean water and dry in the shade; high-efficiency filters are generally not recommended to be washed with water to avoid damaging the filter element.
Detection Methods of Air Filters
There are various methods to detect the performance of air filters. For high-efficiency filters, the common method is to use a dust particle counter sampling head to scan the outlet side, and the detection cycle is usually at least once per quarter.
Newly installed high-efficiency filters should also be detected before use. If the number of 0.5μm particles exceeds the standard or the final air volume of the filter drops to less than 70% of the initial air volume within the detection cycle, it should be dealt with in a timely manner.
Replacement Methods and Precautions of Air Filters
Primary filters are generally replaced every 4 – 8 weeks, medium filters are replaced every 7 – 9 weeks, and high-efficiency filters are replaced every 1 – 2 years.
If a differential pressure gauge is installed, when the differential pressure of the primary filter is greater than 250Pa, the differential pressure of the medium filter is greater than 330Pa, and the differential pressure of the sub-high efficiency filter is greater than 400Pa, it must be replaced.
When replacing, the filter should be isolated first, the intake valve or compressed air supply system should be closed, and the operation should be carried out after the pressure is completely relieved.
When replacing with a new filter, it should be checked for qualification to prevent dust contamination, the installation direction should be correct, and care should be taken not to omit the sealing ring. At the same time, each time the filter is replaced, the interior of the air conditioning unit should be cleaned to avoid dirt remaining in dead corners.
In conclusion, correct cleaning, detection and replacement methods, as well as attention to related matters, can ensure the continuous and effective operation of air filters, providing a good air quality guarantee for the food manufacturing industry.
Successful Application Case Sharing
Domestic Successful Case
In a large domestic food factory, due to poor air quality before, the food has repeatedly had problems such as excessive total bacterial count, seriously affecting the quality of the product and the reputation of the enterprise.
The factory introduced a complete air filtration system, including primary, medium and high-efficiency filters, and installed high-temperature resistant filters on key equipment.
After a period of operation, the air quality has been significantly improved, and the total bacterial count of food has been greatly reduced, reaching the national standard. At the same time, due to the improvement of product quality, the enterprise’s market share has increased, and the economic benefits have significantly improved.
Foreign Successful Case
A well-known frozen food manufacturer in the United States once faced many problems due to poor filters, such as residue in the return air, low filtration efficiency, and short service life. Later, a combination of Camfil 30/30 pre-filters and Hi-Flo ES bag filters was selected.
As a result, more than $33,000 was saved annually, not only reducing energy consumption and costs but also extending the service life of the filters and reducing labor and waste disposal costs. In addition, cleaner air also supports food safety, employee health and equipment operation, bringing multiple benefits to the enterprise.
Future Development Trends and Prospects
Technological Innovation
In the future, technological innovation of air filters in the food manufacturing industry will mainly focus on the research and development of filter materials. New nanomaterials and biomaterials are expected to be widely used to improve filtration efficiency and accuracy while reducing costs.
The integration of intelligent sensors will enable air filters to monitor air quality and their own working status in real-time, achieving intelligent operation and maintenance.
Performance Enhancement
Filtration performance will continue to improve, being able to more effectively remove fine particles, harmful gases and microorganisms, ensuring a highly clean food production environment.
At the same time, with the development of energy-saving technologies, the energy consumption of air filters will be further reduced, in line with the requirements of sustainable development.
Customized Services
The production processes and environments of different food manufacturing enterprises are different. In the future, more attention will be paid to providing customized air filtration solutions for enterprises to meet their specific needs.
For example, for food production environments with high humidity, filters with moisture-proof functions will be developed.
Green and Environmental Protection
During production and use, air filters will pay more attention to environmental protection and reduce the impact on the environment. Recyclable and renewable materials will be used to reduce the pressure of waste filters on the environment.
Integration with Intelligent Manufacturing
As the food manufacturing industry transitions to intelligent manufacturing, air filters will also be deeply integrated with it.
Through interconnection and interoperability with production equipment and control systems, automatic adjustment and optimization can be achieved, improving production efficiency and quality.
In conclusion, the future development of air filters in the food manufacturing industry is full of opportunities and challenges. The continuous progress of technology and changes in market demand will drive continuous innovation and improvement, playing a more important role in ensuring food safety and improving the quality of the production environment.