A square-braided natural-fiber gland packing made from high-grade ramie yarn thoroughly impregnated with PTFE dispersion and a silicone-free lubricant. Designed for rotating and reciprocating pumps, valve stems and marine shaft glands that require a shaft-friendly, low-friction seal with good slurry and water handling characteristics.
Key features
Square-braided ramie fibre with PTFE dispersion and special lubricant (silicone-free options available).
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Low coefficient of friction — gentle on shafts and stems (reduced shaft wear).
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Good resistance to slurry, sand and abrasive media — widely used in water, wastewater and mining/pulp industries.
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Non-contaminating variants for brewing, pharmaceutical and food-related water services (ask for written MSDS / suitability).
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Supplied in coils (metered packs) or pre-formed/die-formed ring sets for rapid maintenance.
Detailed description
Ramie packing impregnated with PTFE is produced by square- or interlock-braiding bleached ramie yarns while saturating the braid, thread-by-thread, with a PTFE suspensoid and a specially formulated lubricant. The PTFE reduces the friction coefficient and improves chemical resistance; the lubricant aids break-in and minimises initial leakage. Compared with untreated natural fibre packings, PTFE impregnation extends service life, reduces maintenance intervals and preserves shaft finish. Typical supplier literature and test data confirm its broad adoption for centrifugal pumps, reciprocating pumps, stern tubes and valve stems.
Typical applications (where buyers use it)
Pumps
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Centrifugal water & wastewater pumps, cooling water, raw water, slurry pumps (low-to-moderate speed).
Valves & Actuators
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Valve stem packing for general industrial and municipal service where a shaft-friendly, non-staining packing is required.
Marine & Stern glands
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Rudder posts, stabiliser shafts and stern tube seals (marine-grade formulations available — silicone-free and food-contact conscientious variants exist).
Food, beverage & pharma (water lines)
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Non-contaminating PTFE formulations are commonly used for potable/processing water lines in breweries and beverage plants — always confirm manufacturer certification.
Technical specifications
Important: specifications vary with exact formulation, lubricant, braid style and core option. The figures below are industry-typical ranges taken from multiple supplier datasheets; always request the manufacturer datasheet for the SKU you intend to buy.
| Property | Typical value / range | Source / note |
|---|---|---|
| Material | Ramie (Boehmeria nivea) yarn (bleached) | Manufacturer product pages. |
| Impregnation | PTFE suspensoid + special lubricant (silicone-free options) | Supplier datasheets. |
| Continuous service temperature | –50 °C to +150 °C (typical) — some formulations quoted to ~+130 °C / +150 °C. | JD Jones, HYSealing and supplier datasheets. |
| Maximum short-term temperature | Up to ~+200 °C for some heavy formulations — verify product datasheet. | Supplier notes; many ramie/organic fibre packings are limited vs synthetic/PTFE packings. |
| pH (chemical service) | Typical service pH 4 – 12 (varies by impregnant). Confirm for aggressive oxidisers. | HYSealing / supplier datasheets. |
| Pressure (guideline) | Rotating: ≈ 20–25 bar; Reciprocating: ≈ 25–30 bar; Static: up to 50 bar (exact limits depend on gland design and number of rings). | Manufacturer datasheets (example ranges). |
| Linear shaft speed (rotating) | Typical working speed 7–10 m/s; some suppliers quote up to 10 m/s (check product). | Supplier datasheets. |
| Construction | Square braid / interlock braid; optional silicone rubber or PTFE core versions; die-formed rings available. | Supplier catalogs. |
| Density / mass | Varies by braid & impregnation; order weights supplied per coil by vendor (use vendor certificate). | IDT / supplier packing units. |
| Colours | Natural white / off-white (PTFE impregnation light colour) | Product images & datasheets. |
Common sizes & supply formats
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Round / square cross-sections (typical stock sizes in mm): 4, 5, 6, 7, 8, 10, 12, 14, 16, 18, 20, 25, 30 mm. (Many suppliers list widths/height range 4–30 mm; custom sizes available on request.)
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Supply formats: coils by metre (sold per metre or per kg), small retail coils (3 m), maintenance coils (8 m, 20 m) and pre-formed / die-formed ring sets cut to pump/valve ID/OD dimensions. Confirm coil weight/length with vendor.
Advantages (why procurement teams choose PTFE-impregnated ramie)
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Shaft-friendly / low wear — ramie fibre plus PTFE reduces abrasive action on shaft finishes compared with many mineral-filled packings.
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Good slurry & abrasive tolerance — braiding + PTFE lubricant resists extrusion and abrasion in sandy waters and pulp/sludge.
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Lower cost vs high-end synthetics — offers a balance of performance and price vs full synthetic or aramid packings in many water/wastewater applications.
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Non-staining / food-safe variants — PTFE + paraffin or silicone-free lubricants reduce contamination risk for brewing and beverage water lines (certify before use).
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Easy to install — available as pre-formed ring sets for rapid service and reduced downtime.
Ramie PTFE vs other common packing materials
| Material | Typical continuous temp | Best for | Main trade-offs | Source (examples) |
|---|---|---|---|---|
| Ramie + PTFE | –50 °C to +150 °C | Water, slurry, marine shafts, general pumps & valves | Shaft friendly, cost-effective; lower high-temp capacity vs synthetics | Supplier datasheets. |
| Acrylic + PTFE | up to ~260 °C (supplier typical) | Higher speed pumps, higher temp liquids | Higher temp rating, soft/low abrasion; more expensive | SEPCO / acrylic product pages. |
| Aramid (Kevlar) + PTFE | up to ~260 °C | High abrasion / slurry / heavy duty pumps | Excellent strength & extrusion resistance; more abrasive to shafts in some filament forms | Aramid product pages. |
| Pure PTFE rope | –200 °C to +260 °C (or higher short term) | Corrosive chemistry, ultra-clean services | Best chemical resistance & temp but higher cost and may require more gland load | PTFE technical pages & packing vendors. |
| Graphite based | extremely high temp (varies) | High temp & steam | Excellent heat resistance; can be abrasive and conductive | CRC / packing resources. |
Use this table as a procurement-level quick filter — final selection must consider shaft speed, gland design, number of rings, stuffing box depth and media. Always request vendor test data for your exact application.
Ordering & sizing notes
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How many rings: follow pump vendor guidance (commonly 4 rings for centrifugal pumps; heavy-duty service may require 5–6 rings). Request OEM kit if available.
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Cut-ring length formula: cut length (mm) = π × mean diameter (mm) of stuffing box bore (i.e., π × ((ID + OD)/2) for full rings). Many suppliers provide cut-to-size ring sets on order.
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Request documentation: always request MSDS, material declaration and certificate of conformity; for food/beverage/pharma lines request explicit suitability statements.
FAQ
Q — Is ramie packing impregnated with PTFE asbestos-free and safe for procurement?
A — Yes. Ramie packing is a natural vegetable fibre (non-asbestos). However, always request MSDS and supplier certification; PTFE impregnation and lubricants are industry normal but confirm that the product meets your local regulatory & health/safety rules.
Q — Can I use this packing for steam service?
A — Ramie PTFE packings are typically rated for moderate temperatures (commonly to ~130–150 °C). For sustained high-temperature steam service consider graphite or high-temperature synthetic packings instead. Always check the datasheet for the exact SKU.
Q — What is the typical lead time and supply format?
A — Many vendors stock common sizes (coils and pre-formed rings); standard lead times for custom die-formed ring sets may be a few days to weeks depending on order quantity and exact size. Confirm with the supplier.
Q — Do you offer die-formed ring kits to OEM pump model numbers?
A — Many manufacturers and distributors supply pump/valve packing kits cut to common OEM references (Goulds, Sulzer, etc.). Provide pump model and shaft dimensions when enquiring.
Q — Are there food-grade options?
A — Some PTFE-impregnated ramie products are formulated to be non-staining and silicone-free for beverage applications (brewing, bottled water). Always require supplier’s statement of suitability and MSDS for food/contact claims.