Braided Packings
Stuffing box sealing from chemical pumps to 980 °C steam valves — five grades, one right answer for every service condition.
Overview
The adjustable seal — compression packing done right
Braided packings seal rotating shafts, reciprocating rods, and valve stems in stuffing boxes (gland packings). They are installed as individual cut rings stacked in sequence and compressed by a gland follower — the clamping force creates the seal against the shaft and box bore simultaneously. The seal is inherently field-adjustable: add compression to compensate for wear, add rings to restore sealing depth.
Modern packing materials — expanded PTFE, graphite, PTFE/graphite blends, and aramid-reinforced graphite — have replaced the hemp and asbestos-based packings of previous generations. These materials cover the full pH range (0–14), operate from cryogenic temperatures to 980 °C in superheated steam service, and handle shaft surface speeds to 22 m/s in centrifugal pump applications.
The key to packing performance isn't the product — it's the installation. Poorly cut rings, over-compressed glands, and inadequate shaft surface finish account for the majority of premature packing failures that get blamed on material selection.
Product Grades
Five main grades — 30+ compositions available
The grades below cover the majority of industrial applications. They are the main reference points — not the full catalog. We can source over 30 packing compositions including aramid/PTFE blends, carbon fiber, flax, ramie, PTFE-coated fiberglass, and specialty constructions for nuclear, cryogenic, and corrosion-resistant service. If your application falls outside these grades, describe the conditions and we'll identify the right product.
TME3310
Expanded Pure PTFE Braided Packing
Max. 260 °C (540 °F) · pH 0–14 · Structure: expanded PTFE square braid · Low pressure static / light dynamic service
Made from high-quality expanded pure PTFE filaments, the TME3310 is chemically inert across the full pH range and produces no contamination — making it the first choice for food processing, pharmaceutical manufacturing, and high-purity chemical handling where graphite carry-over is unacceptable. The low-friction surface prevents product leakage through the braid structure itself. Homogeneous construction throughout ensures consistent compression and seating. Typical applications: valves, tanks, agitators, and low-pressure pumps handling corrosive or purity-sensitive fluids in chemical, pharmaceutical, and agri-food sectors.
TME3000
PTFE / Graphite Braided Packing — GFO Type
Max. 285 °C (550 °F) · pH 0–14 · Shaft speed up to 4,500 ft/min (≈ 22 m/s) · Structure: braided PTFE/graphite fiber
The graphite-impregnated PTFE construction gives the TME3000 two properties pure PTFE cannot match: self-lubrication and thermal conductivity. The graphite conducts heat away from the shaft surface — critical in centrifugal pump applications where friction heat is the primary cause of shaft damage and packing deterioration. Chemical resistance remains full pH 0–14. This is the default recommendation for most industrial centrifugal pump service, agitators, and valves in chemical processing, pharmaceutical, and water treatment plants. The GFO-type construction is widely specified by pump OEMs as a direct replacement for asbestos-era packings.
TME3200
Flexible Graphite Braided Packing
Max. 455 °C / 850 °F (air) — 980 °C / 1,800 °F (steam) · pH 0–14 · Shaft speed up to 4,500 ft/min (≈ 20 m/s) · Structure: flexible graphite interlock braid with inorganic reinforcement
High-purity flexible graphite with inorganic reinforcement for service conditions that exceed what any PTFE-based packing can handle. The interlock braid construction provides excellent dimensional stability under thermal cycling — the graphite expands and contracts without losing its seating pressure against the shaft. Outstanding thermal conductivity keeps shaft surface temperatures in check even at high speeds. Used in pumps and valves subject to extreme thermal and chemical stress: boiler feed pumps, steam valves, high-temperature process lines, and equipment in chemical, petrochemical, energy, and metallurgical industries.
TME3200W
Flexible Graphite + Inconel Wire Reinforcement
Max. 455 °C / 850 °F (air) — 1,090 °C / 2,000 °F (steam) · pH 0–14 · Max. pressure: 275 bar (4,000 psi) · Structure: flexible graphite interlock braid with Inconel wire core
The TME3200W takes the graphite packing of the TME3200 and adds Inconel wire reinforcement throughout the braid structure. The Inconel provides mechanical backbone where the graphite alone cannot maintain dimensional integrity under simultaneous high pressure and high temperature — conditions found in high-pressure steam valves, hot gas isolation valves, and critical isolation duty in power generation and petrochemical plants. Maximum thermal resistance in the product line: rated to 1,090 °C in superheated steam service. Specify this grade when the TME3200 has been tried and found mechanically insufficient for the pressure class.
TME3600
PTFE-Impregnated Synthetic Fiber Braided Packing
Max. 260 °C (500 °F) · pH 2–12 · Max. pressure: 207 bar (4,000 psi) · Shaft speed up to 4,500 ft/min (≈ 12.7 m/s) · Structure: interlock braid, PTFE-impregnated synthetic fiber with lubricated coating
An economical asbestos-free packing for medium-pressure service where the extreme temperature and chemical resistance of graphite or pure PTFE grades is not required. Synthetic fibers impregnated with PTFE and a lubricated outer coating provide good chemical resistance, low friction, and increased durability at a competitive cost. Suitable for medium-pressure pumps, valves, and agitators in chemical process, food and beverage, naval, and water treatment industries. pH range is narrower than graphite or pure PTFE grades — verify compatibility for highly acidic or alkaline services. When the application is straightforward and budget is a factor, this is the practical starting point.
Design Reference
Stuffing box design & installation guidance
Stuffing box dimensions & shaft clearance
The stuffing box must provide the right annular space for the packing section, sufficient depth for a minimum number of rings, and controlled clearance at both shaft and box bore. Too loose and the packing extrudes through the gap; too tight and gland adjustment has no room to operate over the service life of the packing.
| Parameter | Design Requirement | Notes |
|---|---|---|
| Packing cross-section | (Box bore − shaft OD) ÷ 2 | This calculation gives you the packing size. Round down to the nearest standard packing section size. Mismatched packing section is the most common sizing error. |
| Minimum number of rings | 4–5 rings for dynamic service; 3 minimum for static valve stems | Fewer rings concentrate compression on insufficient sealing surface. High-pressure applications may require 6–7 rings with a lantern ring between sets. |
| Box depth (minimum) | 5 × packing cross-section for dynamic; 4 × for static | Must allow gland follower engagement of at least 1 × packing cross-section at initial assembly, with room to advance as packing compresses over service life. |
| Shaft diametric clearance | 0.2–0.5 mm (0.1–0.25 mm per side) | Too tight: no room for shaft runout, causes packing to lock and score shaft. Too loose: packing extrudes inward and fails rapidly. Verify shaft runout (TIR) does not exceed clearance. |
| Shaft surface finish (Ra) | 0.4–0.8 µm for rotating shafts; 0.2–0.4 µm for reciprocating rods | Harder shaft materials (Cr-plated or hardened sleeve) extend packing life. Minimum recommended shaft hardness: 45 HRC for high-speed rotating service. |
Ring cutting & installation sequence
Correct ring cutting is not optional — an incorrectly cut ring will not compress uniformly and will create leak paths regardless of packing grade or gland torque. Cut each ring individually to the shaft diameter, not to the box bore.
| Step | Method | Critical Notes |
|---|---|---|
| Cutting the ring | Wrap packing around the shaft (not a mandrel), mark, cut with a sharp knife at 45° for rotary/reciprocating service. Cut square (90°) only for static valve stems. | Cutting on the shaft — not on a rod or dummy mandrel — ensures the ring ID matches the actual shaft. A ring cut too large will buckle in the box. |
| Joint staggering | 90° between adjacent rings (4 rings); 120° for 3-ring sets | Aligning joints creates a direct leak path through the packing stack. Staggering distributes the cut faces through 360°. Mark joint positions before loading rings. |
| Pre-conditioning | Soak PTFE rings in system fluid (where compatible) for 30–60 min before installation. Graphite rings install dry. | Soaking PTFE ring stock reduces compression set during initial gland tightening. Graphite packings self-lubricate — do not add grease unless manufacturer specifies. |
| Seating each ring | Seat each ring individually with a split wooden or PTFE sleeve and tamp gently — do not use a metal bar against the packing face | Each ring must sit flat at the bottom of the box before the next is added. Rings that bridge over voids will not compress predictably under gland load. |
Compression, break-in & adjustment procedure
Packing break-in is a controlled process, not a one-time tighten-and-forget operation. The goal at startup is to allow controlled leakage while the packing beds to the shaft surface — then progressively reduce leakage to the acceptable limit over the first hours of operation.
| Phase | Target Condition | Action |
|---|---|---|
| Initial assembly | Gland finger-tight, then ¼ turn with wrench on each bolt alternately | Do not compress hard before startup. The packing must be free enough to allow controlled leakage once running. Tighten each bolt the same amount to avoid gland cocking. |
| First start | 10–20 drops per minute leakage at operating speed — this is correct | Do not tighten at this stage. The leakage cools the shaft and lubricates the packing-to-shaft interface during bedding-in. Tightening at cold startup scores the shaft. |
| Break-in (2–4 hours running) | Packing beds to shaft — leakage typically decreases naturally | Once operating temperature has stabilized, tighten gland in ¼ turn increments on alternating bolts. Wait 15 minutes between adjustments — compression redistributes slowly through the packing stack. |
| Final operating condition | Rotating: 1–3 drops/min acceptable. Reciprocating: near-zero. Valve stems: zero. | If leakage cannot be controlled to target, check shaft condition (scoring, runout) before adding more rings. Adding rings to a scored shaft is a temporary fix — it will require replacement again soon. |
| Routine re-tightening | Tighten only when leakage exceeds acceptable limit | Do not tighten on a schedule — tighten on condition. Over-compressed packing causes shaft heat, accelerated wear, and bearing overload in centrifugal pumps. |
Need packing for your pump or valve?
Tell us the shaft diameter, box bore, service temperature, fluid, and shaft speed. We'll recommend the right grade and supply cut rings or coil stock — whichever your maintenance team prefers.
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