русский
Deutsch
عربى
Gansu Juxiang Fluoroplastics Technology Co.,Ltd. manufactures PTFE butterfly flange gaskets and the fluoroplastic sealing components around them at our production base in Yumen City, Gansu Province. We are a joint venture of Zhejiang Jiaxiang Fluoroplastics Co., Ltd. and Gansu Juhua New Materials Co., Ltd. of the Juhua Group, with a second production base in Zhejiang, supplying PTFE, PFA, FEP, PCTFE, PEEK and PI products into chemical, pharmaceutical, semiconductor, hydrogen energy and aerospace equipment.
As a PTFE Butterfly Flange Gasket manufacturer we work from flange drawings rather than from a size list alone. Bore, outer diameter, thickness, bolt pattern and sealing face are matched to the joint, and the compound is chosen for the medium, the temperature and the compression load the line actually applies.
A Gasket Range Built Around Flange Practice
The gasket sits between a butterfly valve body and its mating flange, so the outer diameter has to clear the bolt circle while the inner diameter stays clear of disc travel and does not intrude into the flow bore. Our standard JIS program covers 20A to 80A at 4 mm thickness; everything outside that envelope is produced to drawing.
| Gasket code | Flange standard | Outer diameter (mm) | Inner diameter (mm) | Thickness (mm) |
|---|---|---|---|---|
| JIS 20A | JIS | 98 | 21 | 4 |
| JIS 25A | JIS | 122 | 29 | 4 |
| JIS 40A | JIS | 136 | 48 | 4 |
| JIS 50A | JIS | 152 | 58 | 4 |
| JIS 65A | JIS | 172 | 70 | 4 |
| JIS 80A | JIS | 182 | 84 | 4 |
- Non-standard outer and inner diameters, thicknesses and oval or oblong outlines are cut and machined to order.
- Full-face versions with bolt holes, tabbed and handle-type outlines, and reduced-bore rings for lined pipework.
- Gaskets are also supplied as part of a wider sealing set for pump and valve connections, reactors and heat exchangers.
Material Options Within the PTFE Family
Unfilled PTFE gives the widest chemical resistance in the range and is the default where strong acids, alkalis, organic solvents and oxidizing agents are present and mechanical load is moderate. Where the joint is heavily bolted, thermally cycled or space-limited, the compound changes rather than the geometry.
- Modified PTFE — higher density and markedly lower deformation under load, used where cold flow of standard PTFE would loosen the joint. See our Modified PTFE Gasket range.
- Filled PTFE — glass, carbon, graphite or bronze grades for higher compressive strength and better heat dissipation in valve and pump flanges; filler choice follows the medium, since glass is unsuitable in strong alkali and hydrofluoric service.
- Expanded PTFE — soft, highly conformable multi-directional material for glass-lined, FRP and pitted flanges where bolt load is limited. Covered by our Expanded PTFE Reinforced Flange Gasket line.
- PFA-backed glass fiber sheet — for large diameter and high-load flanges that need dimensional stability with a chemically inert face.
Filled and modified grades are produced in-house from our own sheet and rod, so the compound record and the finished gasket stay traceable to the same batch. The Filled PTFE Product range covers the base materials used for these joints.
Specifications We Confirm Before a Gasket Is Cut
- Flange standard, nominal size and pressure class, plus facing type: raised face, full face, tongue and groove, or groove-only.
- Outer diameter, inner diameter, thickness and the dimensional tolerance that applies to each.
- Bolt circle and bolt hole diameter where a full-face pattern is required.
- Medium, concentration and the continuous versus peak temperature the joint will see.
- Operating pressure, vacuum condition and any pressure cycling.
- Available bolt load, bolt size and material, and the torque value the site will apply.
- Cleanliness or purity class for semiconductor, pharmaceutical and food-contact service.
- Marking, packaging format and the documentation to travel with the shipment.
Fitting the Gasket to Butterfly Valve and Wafer Flanges
PTFE seals by being compressed, and it continues to deform slowly under sustained bolt load. Thickness therefore has to be matched to the bolt load available at the joint: a thicker ring conforms better to an imperfect face but consumes more of the bolt preload and increases creep. We confirm the thickness against the flange drawing rather than defaulting to the standard 4 mm.
- Centre the gasket on the bolt circle so no part of the ring overlaps the bore or the disc sweep.
- Tighten in a cross pattern in at least two stages, then re-torque after the first thermal cycle.
- Keep the gasket flat and supported until installation; PTFE takes a permanent set if stored bent or stacked under load.
- Do not use gasket thickness to compensate for flange misalignment or damaged sealing faces.
- On lined pipework, check that the lining is not pinched between the gasket and the flange face.
Quality Control, Custom Configurations and Delivery Scope
Gaskets are cut and machined from our own PTFE sheet and rod, with process parameters monitored through production and each lot checked against the approved drawing. Inspection covers outer and inner diameter, thickness, flatness, edge quality and freedom from voids, delamination or contamination; results are recorded against the order.
Customization is our core service. We produce to drawings or to samples, including non-standard outlines, compound changes, split and tabbed designs, and kits combining gaskets with O-rings and packing for a single valve or pump overhaul.
- Documentation agreed at order stage: dimensional records, material batch identification, certificate of conformity and packing list.
- Gaskets packed flat, interleaved and protected from UV and deformation for sea and air freight.
- Scheduling across the Gansu and Zhejiang bases for repeat and project quantities.
- Usage guidance and technical follow-up after delivery, with inquiries answered within 12 working hours.
Information We Use to Configure Your Solution
- Flange drawing, or the standard, size and pressure class together with the facing type.
- Required outer diameter, inner diameter and thickness, with tolerances where they are critical.
- Medium, concentration, continuous and peak temperature, and operating pressure or vacuum.
- Bolt size, bolt material and the torque the maintenance team will apply.
- Quantity per size, annual consumption and whether the order is a one-off project or a replenishment schedule.
- Purity or cleanliness requirements, marking, packaging and labelling instructions.
- Acceptance requirements, third-party inspection and the destination port or site.
Frequently Asked Questions
Which sizes of PTFE butterfly flange gasket do you supply?
The standard program covers JIS 20A to 80A at 4 mm thickness, from 98 mm to 182 mm outer diameter. Other sizes, other flange standards and non-standard thicknesses are produced to drawing, including full-face patterns with bolt holes.
Should the gasket be virgin, modified or filled PTFE?
Virgin PTFE suits the broadest range of aggressive media at moderate load. Modified PTFE is selected where cold flow and bolt-load retention matter, and filled grades where compressive strength or heat dissipation is the limiting factor. We match the compound to the medium, temperature and bolt load you specify.
What thickness is used between a butterfly valve and its mating flange?
Our JIS program is 4 mm, which suits most raised-face joints at normal bolt load. Thinner rings are used where space or bolt preload is limited, and thicker rings where the flange faces are less than perfect. The value is confirmed against your flange drawing and torque figure.
What do you need to quote a gasket order?
A flange drawing or the standard, size and pressure class, the medium and temperature, the quantity per size, and any cleanliness, marking or documentation requirement. With those details we return a configuration and price, and reply to inquiries within 12 working hours.
