Sanitary Blind Ferrules / Solid End Caps (Machined from Bar Stock)
In a sanitary loop, the Blind Ferrule (or End Cap) is subjected to the full hydraulic force of the system pressure. Unlike flow-through fittings, the blind cap creates a “dead end” where pressure spikes concentrate. Many low-cost suppliers offer investment cast caps, which are prone to microscopic porosity and undetectable leaks under high-pressure testing. Sunhyings manufactures Blind Ferrules exclusively from Solid Stainless Steel Bar Stock. This ensures a dense, uniform grain structure with zero porosity, capable of withstanding high-pressure hydro-testing and creating a secure barrier for future line expansion or instrumentation ports.
- Method: CNC Machined from Solid Bar (Not Cast).
- Integrity: Zero porosity; ideal for high-pressure testing.
- Surface: Ra ≤ 0.8µm (Standard) / 0.38µm (Electropolished).
- Material: 316L (1.4404) for wetted corrosion resistance.
- Marking: Heat Number & Size Laser Etched.
- Supply: Bulk Crates for OEMs & Stockists.
Technical Specifications
Product Name
Sanitary Blind Ferrule / Solid End Cap / Blanking Disc
Manufacturing Method
CNC Machining from Solid Bar Stock (Forged quality)
Material Grades
Stainless Steel 304 (1.4301) / 316L (1.4404)
Standards Compliance
ASME BPE, DIN 32676 (Series A/B), ISO 1127, 3A
Pressure Rating
Exceeds rating of the mating clamp (Solid steel structure)
Size Range
1/2″ (DN10) to 12″ (DN300)
Surface Finish (Internal)
Standard: Ra ≤ 32µin (0.8µm); Pharma: Ra ≤ 15µin (0.38µm) EP
Modifications
Machinable (Can be drilled for 1/4″ NPT or instrument probes)
1. Eliminating Porosity Risks (Bar Stock vs. Casting) Cast blind caps are cheaper but risky. During hydrostatic pressure testing (often 1.5x working pressure), cast caps can “weep” fluid through microscopic voids in the metal grain. Sunhyings uses only Solid Bar Stock. This guarantees a dense, homogenous material structure that will never leak through the body, providing absolute safety for end-of-line termination.
2. Reducing Biofilm in “Dead Legs” A blind cap creates a static zone (dead leg) where fluid does not flow vigorously. If the surface finish is rough, biofilm will accumulate rapidly. We polish the face of our blind ferrules to a guaranteed Ra ≤ 0.8µm (32µin). For pharmaceutical WFI (Water for Injection) loops, we offer Electropolishing to Ra ≤ 0.38µm to maximize corrosion resistance and cleanability in these low-flow zones.
3. Versatility for Modification Because our caps are solid steel (not hollow-backed castings), they are the ideal substrate for OEM modifications. Engineers can drill and tap these caps to install pressure gauges, temperature probes, or steam trap drains directly into the end of a manifold, saving the cost of an additional instrument tee.
Note: The “Flange OD” is the critical dimension for clamp selection. 1.0″ and 1.5″ sizes share the same flange.
| Nominal Size (Tube) | Flange OD (A) | Thickness (B) | Weight (Approx) | Stock Status |
| 0.50″ – 0.75″ | 25.0 mm | 6.35 mm | 0.03 kg | In Stock |
| 1.00″ – 1.50″ | 50.5 mm | 6.35 mm | 0.08 kg | In Stock |
| 2.00″ | 64.0 mm | 6.35 mm | 0.15 kg | In Stock |
| 2.50″ | 77.5 mm | 6.35 mm | 0.22 kg | Bulk Available |
| 3.00″ | 91.0 mm | 6.35 mm | 0.35 kg | Make to Order |
| 4.00″ | 119.0 mm | 7.92 mm | 0.68 kg | Make to Order |
| 6.00″ | 167.0 mm | 11.1 mm | 1.80 kg | Make to Order |
1. Safety During Pressure Testing
The Hazard: The blind cap acts as a piston. If the clamp fails under pressure, the cap becomes a projectile.
The Protocol: Always use a High-Pressure Bolted Clamp (not a wingnut clamp) for end-of-line caps subjected to hydro-testing. Never stand directly in line with a pressurized blind cap.
2. Preventing “Dead Leg” Issues
Rule of Thumb: When installing a blind cap on a tee branch, keep the branch length ($L$) as short as possible relative to the diameter ($D$). The target is an $L/D$ ratio of $< 2:1$ to ensure turbulence from the main line cleans the cap face.
3. Gasket Selection
Since blind caps are often left in place for long periods, we recommend PTFE or Platinum Cured Silicone gaskets which resist sticking/adhesion to the steel face over time, making maintenance removal easier.
Related Products
FAQ
Can I drill a hole in a Sanitary Blind Ferrule?
Yes. Since Sunhyings Blind Ferrules are machined from solid bar stock (not hollow castings), they can be drilled and tapped to accommodate NPT fittings, thermowells, or bleeding valves without compromising structural integrity.
What is the difference between 304 and 316L Blind Caps?
316L contains Molybdenum (2-3%), which provides superior corrosion resistance against chlorides and sanitizing chemicals. We recommend 316L for all “wetted” parts (parts touching the product), while 304 is acceptable for non-contact areas or general utility lines (water/air).
How do I size a Blind Cap for a 1.5-inch line?
You must match the Flange OD. A standard 1.5-inch sanitary line uses a 50.5mm flange. Therefore, you need a blind cap with a 50.5mm OD. Note that 1-inch lines also use the 50.5mm flange, so the same blind cap fits both 1″ and 1.5″ lines.
What is the maximum pressure a Blind Ferrule can withstand?
The stainless steel blind cap itself can withstand pressures exceeding 100 bar (1450 PSI). However, the limiting factor is the clamp and gasket. You must check the pressure rating of the clamp holding the cap. For high-pressure isolation, always use a bolted high-pressure clamp.
Do you provide MTRs for Blind Ferrules?
Yes. For B2B customers, traceability is essential. We provide EN 10204 3.1 Mill Test Reports listing the chemical composition and mechanical properties of the steel heat lot for every shipment of blind ferrules.