Definition: Non-pressure hygienic manways are specifically designed access points that are used in various industries where maintaining strict hygienic conditions is crucial, such as food, beverage, and pharmaceutical sectors. They are engineered to allow for easy entry and exit of personnel into equipment or containers for inspection, maintenance, and other necessary operations, all while ensuring a high level of hygiene and without being subjected to significant internal pressure differentials.
Characteristics:
Exceptional Sealing for Hygiene: These manways are equipped with top-notch sealing mechanisms. High-quality sealing materials like silicone rubber or PTFE (polytetrafluoroethylene) gaskets are used, along with advanced sealing configurations such as tongue and groove or flange sealing methods. This ensures that even in a non-pressurized state, no external contaminants, including dust, microorganisms, etc., can penetrate the interior of the container, thereby safeguarding the purity and quality of the substances inside.
Smooth and Hygienic Interior Surface: The inner surface of the manway is meticulously polished to a high level of smoothness, typically with a surface roughness of Ra0.8 - Ra1.6μm. This smooth finish not only enables effortless cleaning and thorough disinfection but also minimizes the likelihood of any substances adhering to the surface, thus preventing the growth of bacteria and other harmful organisms.
Hygienic Material Selection: Usually made of materials that are highly suitable for hygienic applications. Stainless steel grades like 304 or 316L are commonly employed due to their excellent corrosion resistance and biocompatibility. These materials do not react with the substances being processed, whether it's food, beverages, or pharmaceuticals, ensuring the safety and integrity of the final products.
Structural Design
Manway Cover: Often features a design that allows for quick and easy opening and closing. For example, a hinged or clamped cover, such as a butterfly or oval-shaped cover, can be swiftly operated, significantly enhancing the efficiency of accessing the equipment interior. The thickness of the cover is determined based on factors like the size of the container and the expected pressure conditions (even though it's a non-pressure manway, some minor pressure variations might still occur), typically ranging from 5mm to 10mm to ensure both strength and proper sealing.
Body Section: The body of the manway is welded to the container wall and has a height usually between 150mm and 300mm to provide sufficient space for personnel to enter and exit easily. The diameter of the manway body is selected according to specific application requirements, with common sizes including DN400, DN500, etc.
Sealing Arrangement: In addition to the main sealing gasket, additional sealing elements like sealing grooves and O-rings may be incorporated. For instance, in a tongue and groove sealing system, the gasket is placed within the groove, and when the cover is tightened, the gasket is compressed to fill the groove completely, achieving a highly reliable seal.
Application Fields and Precautions
Application Fields:
Food Processing: In the production of various food products such as dairy, beer, and canned goods, numerous storage tanks, fermentation tanks, etc., are used. Non-pressure hygienic manways enable operators to enter these tanks for cleaning, maintenance, and inspection, ensuring that the food products meet the highest standards of quality and hygiene.
Pharmaceutical Manufacturing: Pharmaceutical production involves the use of reactors, extraction tanks, and storage tanks, all of which have extremely strict hygienic requirements. Non-pressure hygienic manways play a vital role in ensuring that these processes are carried out in a contamination-free environment, thereby maintaining the quality and efficacy of the drugs produced.
Biotechnology Applications: In biotech operations such as biological fermentation and cell culture, these manways provide a safe and hygienic access point for operators to enter the equipment for monitoring, adjustment, and maintenance operations, ensuring the smooth progress of the biotech processes and the quality of the resulting biological products.
Precautions:
Regular Inspection and Maintenance: Despite being designed for non-pressure conditions, these manways still require regular inspection of the sealing components for signs of wear, aging, or damage. The manway cover and body should also be checked for corrosion. Any issues detected should be addressed promptly by replacing or repairing the affected parts.
Proper Operation: Operators should follow the correct procedures when opening and closing the manway cover. Improper handling can lead to damage to the sealing mechanism or deformation of the manway components, which will affect the sealing performance and the overall lifespan of the manway.
Cleaning and Disinfection: After each use, the manway should be thoroughly cleaned and disinfected. Appropriate methods such as hot water rinsing, steam sterilization, or chemical disinfection with suitable agents should be used to ensure that no residue or bacteria remain on the manway surface, maintaining its hygienic condition.
