Convoluted PTFE Outside Braided Tubing

BESTYIELD Technology (Huizhou) Co., Ltd. is one of the leading manufacturers and suppliers of convoluted ptfe outside braided tubing in China, also supports customized service. Welcome to wholesale bulk convoluted ptfe outside braided tubing in stock here and get pricelist from our factory. For price consultation, contact us.

 

The PTFE 904 series integrates a convoluted PTFE core with an external wire braid reinforcement, delivering a unique balance of multi-axis flexibility and pressure containment for dynamic industrial applications. Core features include:

• Convoluted tubing: PTFE (Polytetrafluoroethylene) - corrugated geometry provides axial compression, lateral offset, and angular deflection capability
• Color: Natural or multiple colors - natural PTFE for chemical purity; color options for multi-line system identification
• Outside braid: Polyester or stainless steel - constrains over-expansion and adds burst strength while maintaining convoluted flexibility
• Temperature range: -150°C to +250°C - cryogenic to high-temperature chemical processing capability
• Compliance standards: RoHS, REACH - European environmental and hazardous substance compliance
• Flame resistance rating: HB, V1, V2 - self-extinguishing and limited-burn classifications

 

The 904 series merges the flexibility of convoluted PTFE with the pressure containment of external wire braid, creating a hose that occupies a unique middle ground between the high-pressure 902 series and the high-flexibility 903 series. The convoluted PTFE core provides multi-axis movement capability - axial compression, lateral offset, and angular deflection - while the stainless steel or polyester braid constrains over-expansion and adds burst strength up to 10 MPa. This hybrid architecture is engineered for applications that demand both chemical resistance and dynamic movement: vibration isolation on pump connections, thermal expansion compensation in process piping, and articulating joints on automated equipment. The 904 series is our most versatile PTFE product, serving chemical, food, pharmaceutical, and general industrial customers with a single hose solution.

The engineering challenge in the 904 series lies in achieving adequate braid-to-convolution engagement. Unlike smooth-bore tubing where the braid contacts a uniform cylindrical surface, the convoluted geometry creates alternating peaks and valleys that the braid must conform to without bridging or gapping. Our proprietary braid application process uses a variable-tension braiding head that adjusts wire tension in real time as the hose rotates, ensuring consistent braid contact at every convolution. The braid angle is set at 58±3° - slightly steeper than the 902 series - to accommodate the larger effective diameter at the convolution peaks while maintaining pressure containment at the valleys.

 

Chemical processing plants install 904 series hoses as flexible connectors between rigid PTFE-lined piping and rotating equipment (centrifugal pumps, mixers, compressors), where vibration and misalignment would fracture rigid joints within months. In food and beverage production, these hoses bridge the gap between fixed CIP supply lines and movable tank manifolds, maintaining PTFE purity while accommodating the positional adjustments needed for different batch recipes. Power generation facilities use 904 series for flue gas desulfurization reagent injection lines, where thermal cycling between ambient and 200°C requires a hose that expands and contracts without fatigue failure. The 904 series is also specified in HVAC systems for chilled water connections to fan coil units, combining PTFE longevity with the flexibility to absorb building settlement and pipe stress.

In the pharmaceutical sector, the 904 series serves as the vibration-isolating connection between sterile processing vessels and their associated pump and valve skids. The convoluted PTFE absorbs pump-induced vibration that would otherwise transmit through rigid connections, protecting seal integrity on vessel nozzles. Food processing plants value the combination of PTFE's non-stick surface (preventing product buildup) with the flexibility needed to connect stationary piping to tilting kettles and rotating filling heads.

 

Part Number	Hose I.D.		Hose O.D.		Working Pressure		MIN. Bend Radius
	inch	mm	inch	mm	psi	MPa	inch	mm
904-01	3/16	4.0	0.24	6.0	1450	10.0	7/16	11
904-02	1/4	6.0	0.31	8.0	1450	10.0	9/16	15
904-03	5/16	8.0	0.39	10.0	1450	10.0	3/4	19
904-04	3/8	10.0	0.47	12.0	1160	8.0	7/8	23
904-05	1/2	12.0	0.55	14.0	870	6.0	1	25
904-06	9/16	14.0	0.63	16.0	725	5.0	1-3/16	30
904-07	5/8	16.0	0.75	19.0	725	5.0	1-7/16	37
904-08	3/4	19.0	0.87	22.0	580	4.0	1-11/16	43
904-09	1	25.0	1.14	29.0	435	3.0	1-3/4	45

 

• Remarks: Inner and outer diameter sizes are customizable.

 

The 904 series offers compelling advantages over competing hose technologies across multiple application scenarios. Compared to rubber hoses (including CR, EPDM, and NBR types), PTFE eliminates chemical swelling entirely, extending service life by 3-5× in aggressive chemical environments. Rubber hoses typically require replacement every 12-18 months in continuous chemical service, while PTFE-lined hoses routinely exceed 5 years under identical conditions.

Versus the smooth-bore braided PTFE 902 series, the 904 sacrifices approximately 50% of pressure capacity (10 MPa vs 19 MPa maximum) but gains multi-axis flexibility that the 902 cannot provide. For applications requiring both movement and pressure, the 904 is the clear choice.

Against metal bellows expansion joints, the 904 offers lighter weight (approximately 40% less for equivalent diameter), and chemical resistance that stainless steel bellows cannot match when handling aggressive media such as chlorinated solvents or concentrated mineral acids.

Compared to unplasticized PVC, the 904 withstands temperatures 5× higher (250°C vs 50°C) with zero plasticizer migration - a critical advantage in food, pharmaceutical, and ultra-pure water applications.

 

Every production run of 904 series hose undergoes a comprehensive 5-step quality control process.

Step 1: Incoming PTFE resin testing verifies tensile strength and specific gravity per ASTM D4895, ensuring raw material consistency before processing begins. Any batch falling outside specification is quarantined and returned to the supplier.

Step 2: Convolution forming inspection uses optical measurement to verify pitch uniformity within ±0.5mm and detect any surface scratches, nicks, or deformation that could create stress concentration points under pressure.

Step 3: Braid application verification confirms wire count per carrier matches the engineering specification and measures braid coverage angle at three points along the hose length using a digital protractor.

Step 4: Hydrostatic proof test applies 1.5MPa pressure for 120 seconds, with visual inspection for leakage, permanent deformation, or braid distortion.

Step 5: Final visual inspection and dimensional audit per AQL 1.0 sampling plan verifies overall length, diameter, and cosmetic quality. All test records are stored digitally for 5 years and are accessible via QR code printed on each product label, enabling full traceability from manufacturing floor to end-user installation.

 

 

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