Flexible graphite
Die-formed graphite rings for high-temperature service and broad chemical compatibility.
Stem Packings
Moss Seal supplies stem packings to seal valve stems where they pass through the bonnet, keeping process fluid and gas from leaking to atmosphere. Installed as a set of rings in the stuffing box and compressed by the packing gland, the packing seals tightly against the stem and bore while still letting the stem turn or rise as the valve operates. We match packing style, material, and ring count to your valve type, pressure, temperature, and media, from gate and ball valves to chokes and wellhead equipment.
ENGINEERING
Cross-section design & operation
A stack of packing rings fills the stuffing box between stem and bore, and gland load compresses the set so each ring seals against both surfaces.
Ring styles
Compression packing uses braided or die-formed rings that seal under gland load. Chevron-style sets nest V-rings between male and female adapters, so the lips flare against stem and bore and pressure adds to the sealing force.
How it works
Tightening the gland squeezes the rings axially, pushing them outward against the stuffing box bore and inward onto the stem. The rings hold that contact as the stem rises, falls, or turns, keeping media inside the valve.
Wear & adjustment
As rings wear or relax, packing stress drops and the stem can begin to weep. Adjusting the gland restores compression so the set keeps sealing, extending the interval between repacks and reducing valve downtime.
SELECTION
Materials & advantages
Performance advantages
Tight stem sealing · Adjustable for wear · Smooth stem operation · Broad chemical resistance · High-temperature options · Simple repacking
