Nitrile
General-purpose oil and fuel resistance for moderate-duty sealing applications.
Packing Elements
Moss Seal supplies molded packing elements for downhole and surface pressure-control tools where a large volume of elastomer must deform to seal an annulus or close around pipe. From single-element and multi-element packer stacks to annular and ram packers for blowout preventers, each element is molded in a compound matched to the well fluid, temperature, and pressure rating, with metal or fabric reinforcement where the design requires it. We work from your tool drawing to supply elements that set reliably, hold pressure through the job, and release cleanly.
ENGINEERING
Cross-section design & operation
A solid or reinforced elastomer body is compressed axially so it expands radially, filling the gap between the tool and the casing, wellbore, or pipe and forming the seal.
Element design
Packer elements are typically stacked in sets of three, with a softer center element for sealing and harder end elements to resist extrusion. Metal back-up shoes, garter springs, or bonded end rings control expansion and stop the rubber flowing past the gap at pressure.
How it works
Setting force compresses the element between the tool's mandrel and gauge rings. The elastomer has nowhere to go but outward, so it swells into contact with the mating surface and conforms to its shape, including roughness and slight out-of-roundness.
Pressure response
Once set, differential pressure loads the element harder against the sealing surface, so contact stress increases with demand. Harder end elements and anti-extrusion features carry the load at the gap, keeping the softer sealing element in place through pressure and temperature cycling.
SELECTION
Materials & advantages
Performance advantages
Seals large annular gaps · Conforms to irregular bores · Pressure-assisted sealing · Controlled extrusion · Stable through thermal cycling · Compound matched to well fluid
