M4 x 30mm Hygienic Low Flanged Hex Bolt 3-A SSI - Stainless Steel (316) Description
The M4 x 30mm Hygienic Low Flanged Hex Bolt 3-A SSI - Stainless Steel (316) has the following features:
- Additional Compliances: 3-A SSI
- Polished Finish
- Flange Diameter (D): 10 mm
- Gasket Operating Temperature: -80°C / +150°C
- Gasket Shore Hardness: 85 A
- Gasket Shore Hardness Tolerance: +0/-10
- Head Height (H): 5 mm
- Length (L): 30 mm
- Manufacturing Standard: Not Standardised
- Stainless Steel - (316) / Rubber - EPDM
- Screw / Washer Material Classification
- Stainless Steel / Rubber Material Family
- Stainless Steel - (316) / Ethylene Propylene Diene Monomer Material Specification
- Socket Size (J): 7 mm
- Socket Size (J) Tolerance: +/-0.1 mm
- System of Measurement: Metric
- Thread Pitch: 0.7 mm
- Thread Size: M4 (4 mm)
- Thread Specification: Metric Coarse
- Washer Thickness (W): 1.5 mm
Discover more about the Hygienic Bolts range.
In demanding environments like food processing and pharmaceuticals, standard precision fasteners simply will not cut it. Hygienic bolts, also known as hygienic screws or hygienic fasteners, are precision-engineered to eliminate contamination risks.
Featuring a highly polished finish and a specialised hex head design, these fasteners provide a completely smooth, ultra-cleanable surface. The most defining physical feature of a hygienic bolt is the integrated silicone gasket situated directly beneath the flange. This design choice ensures a completely flush, impermeable seal against mating surfaces, preventing contamination before it can even start.
How Hygienic Bolts Work.
Traditional fasteners have microscopic crevices and gaps beneath the bolt head where moisture, bacteria, germs and debris can pool, creating a breeding ground for contamination.
Hygienic bolts solve this issue through mechanical isolation. When installed, the bolt is torqued down until the integrated silicone gasket compresses against the host component. This creates an airtight, watertight barrier that completely seals the clearance hole.
Consider a high-speed beverage bottling line or a commercial bakery. During daily washdown cycles, high-pressure sanitising sprays can easily trap liquid behind standard bolt heads, leading to bacterial growth or crevice corrosion. By switching to hygienic fasteners, the polished exterior allows cleaning fluids to sheet off effortlessly, while the sub-flange silicone gasket ensures no moisture traps behind the head. This dramatically accelerates Clean-in-Place (CIP) procedures, minimises machinery downtime and helps towards compliance with strict health and safety regulations.
Materials Hygienic Bolts Are Made From.
To ensure maximum longevity and compliance within sterile environments, Accu's range of hygienic bolts are manufactured from premium, high-performance materials.
- Stainless Steel (304): This material provides exceptional resistance to corrosion, oxidation and harsh chemical sanitising agents, ensuring the fasteners maintain structural integrity and a pristine surface finish during repeated washdown cycles.
Sizes and Types of Hygienic Bolts Available.
Accu offers a comprehensive range of hygienic bolts tailored to meet exact engineering specifications. These fasteners feature a fully polished finish to facilitate rapid cleaning and optimal sanitation.
Thread sizes span from M4 (4 mm) up to M20 (20 mm) in diameter, with component lengths ranging from 8 mm to 80 mm to accommodate various panel thicknesses and joint depths.
For installation and high-torque tightening, they feature a robust hex socket drive type, available in sizes ranging from 7 mm to 27 mm. Additionally, these resilient fasteners are built to withstand extreme operating conditions, safely performing over a wide temperature range of -50°C to +190°C without compromising the silicone gasket's sealing integrity.
FAQs.
Q: How do you correctly install a hygienic bolt to ensure the gasket seals properly?
To achieve an optimal seal, the hygienic bolt should be tightened until the sub-flange silicone gasket compresses evenly against a clean, flat mating surface. Care should be taken to ensure the gasket is firmly seated and fully fills the gap without being over-compressed to the point of displacement or distortion, which maintains a reliable barrier.
Q: Can these hygienic screws be used alongside standard nuts and washers?
A: While they feature standard metric threads and can physically mate with standard hex nuts, it is highly recommended to pair them with matching hygienic nuts, hygienic washers or install them into blind tapped holes. Using standard, unpolished nuts or open washers can reintroduce crevices where bacteria can breed, defeating the purpose of the hygienic fastener system.
Q: Are the silicone gaskets on hygienic fasteners replaceable?
A: Yes, Accu can supply replacement hygienic washers and gaskets for your hygienic fasteners. Over extended periods of extreme thermal cycling or exposure to aggressive chemical washdowns, elastomeric sealing components may require routine maintenance and replacing them ensures your machinery retains its airtight, watertight security.
Q: How do you install hygienic fasteners to avoid scratching the polished finish?
A: To preserve the ultra-smooth, polished finish of a hygienic screw, you should always use tools equipped with soft-jawed inserts or protective polymer sleeves over the hex socket drive. Scratching the surface creates microscopic crevices where bacteria and debris can collect, directly compromising the fastener's hygienic integrity and cleanability.
