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KF Flange Vacuum Bellows Stainless Steel Flexible Hose
KF flange vacuum bellows flexible hoses are widely used in high-vacuum pipeline systems where flexible, leak-tight connections are required.
Each hose is built from thin-wall stainless steel with either spiral or annular corrugations, providing excellent flexibility and vibration absorption.
They serve as a crucial link between vacuum components—allowing easy installation, disassembly, and system adjustment without tools or bolts.
YDCT supply a full range of stainless-steel vacuum bellows in KF, ISO, and CF standards. The KF flange hose is designed to absorb positional offsets, reduce vibration transmission, and handle both static and dynamic movement under vacuum or clean-gas conditions.
Each hose is built from thin-wall stainless steel with either spiral or annular corrugations, providing excellent flexibility and vibration absorption.
They serve as a crucial link between vacuum components—allowing easy installation, disassembly, and system adjustment without tools or bolts.
YDCT supply a full range of stainless-steel vacuum bellows in KF, ISO, and CF standards. The KF flange hose is designed to absorb positional offsets, reduce vibration transmission, and handle both static and dynamic movement under vacuum or clean-gas conditions.
Standard & Stock Items
Our regular KF flexible hoses cover KF10–KF50 sizes, available in standard lengths ranging from 100 mm to 2000 mm. Each hose comes with:
KF Flanges (304/316L stainless steel) welded on both ends.
Leak rate ≤ 5×10⁻⁹ Pa·m³/s, helium tested.
Bending life over 10,000 cycles, depending on installation conditions.
Operating temperature: −196°C to +450°C.
We try to keep standard items in stock for quick delivery, but large-volume or specific-length orders usually require a short production lead time.
Since the bellows are thin-walled, over-bending or torsion can reduce lifespan—something to keep in mind during installation.
As one of the experienced manufacturers of metal bellows, we’ve spent years working on how to make vacuum bellows more reliable and easier to fit into different systems.
We pay attention to the practical things, how the material behaves under stress, how the weld holds up over time, and how the sealing performs when the system runs continuously.
Customization Options & Clamp
You can choose from:
Custom lengths or flange combinations (KF–KF, KF–ISO, KF–CF)
Material options: SS304, SS316L, or welded thin-wall tubing
Braid type: Single, double, or none
Welding and surface treatment: Vacuum annealed, polished, or passivated
Each hose can be paired with matching KF clamps and centering rings (with O-ring) for complete assembly.
We recommend ordering the hose together with clamps to ensure compatibility.
| Accessory | Description | Notes |
|---|---|---|
| KF Clamp | Aluminum or stainless steel quick clamp | Easy on/off, no tools required |
| Centering Ring | Stainless steel + Viton / NBR O-ring | Used between flanges for tight sealing |
| Flange Set | Clamp + Ring + Hose Ends | Commonly supplied as one set |
FAQ:
Q: Can I use my own KF clamps?
Yes, as long as they meet ISO-KF dimensional standards, they’ll fit. Just check the O-ring material compatibility with your gas type or temperature range.Q: Can these hoses handle pressure?
They’re primarily for vacuum service, but they can handle limited positive pressure depending on braid configuration and wall thickness.
Applications / Industries Served
You’ll see KF flexible bellows in nearly every vacuum-related field. They’re used to connect chambers, pumps, and gauges while allowing for vibration absorption or movement.
Common industries include:
Vacuum semiconductor and thin-film deposition systems
Analytical instruments and R&D equipment
Photovoltaic and solar module production
Medical and pharmaceutical vacuum lines
Aerospace and defense test facilities
Precision optics, coating, and vacuum furnaces
Although the hose is reliable for most clean vacuum applications, it’s not ideal for corrosive gases or mechanical load-bearing setups. If you’re not sure, just reach out — we can help you match the right hose type and connection.
| Item | Standard Corrugated Tube | High Vacuum Corrugated Tube |
|---|---|---|
| Thickness | 0.28 mm | 0.2 mm (KF16/KF25) / 0.25 mm (KF40/KF50) |
| Corrugation Type | Irregular | Annular type |
| Pitch | Irregular | 5 / 6.5 / 8 / 9 |
| Welding Process | Domestic welder, manual welding, oxidation discoloration | Vacuum welding process, smooth weld seam |
| Material | Stainless steel | 304 stainless steel |
| Outer Diameter | Irregular | 26 / 34 / 53 / 64 |
| Clamp Diameter | 30, 40, 55, 75 mm | 30, 40, 55, 75 mm |
| Ultimate Vacuum | ≥ 5 Pa | 1×10⁻⁹ Pa (0.000000001 Pa) |
| Leak Rate | Rough vacuum (irregular) | ≤ 5×10⁻¹⁰ Pa·m³/s |
| Flexibility | Relatively hard, can be bent slightly | Soft, flexible, extendable, compressible |
| Applications | Domestic vacuum pump, water ring pump, vacuum generator, gas exhaust line | Combination pumps, molecular pumps, diffusion pumps, mechanical booster pumps, vacuum furnaces |
The manufacturing process of the bellows is technically demanding. Helium leak testing is required to verify quality.
Factors such as welding process, stainless steel grade, wall thickness, corrugation pitch, and metal fatigue all affect vacuum tightness and flexibility. Please select the appropriate model according to your application requirements.
