Hybrid pressure seal
A hybrid pressure seal for use in a plunger bore or a stuffing box used in a plunger bore. The hybrid seal has a first, inner seal made of a first, durable material. The inner seal has a cut-out formed in its outer surface in which an outer seal is placed. The inner seal may have features on its inner surface such as V-shaped protrusions or a D-shaped surface. The outer seal is elastomeric. One or more hybrid seals of different configurations may be used in a packing, disposed between a junk ring and a lantern ring. The lantern ring may be integral with and made of the same material as an adjacent hybrid seal.
1 . A plunger packing comprising:
a junk ring; and
a monolithic piece, comprising:
a lantern ring; and
at least one hybrid seal, comprising:
an inner seal, the inner seal having an outwardly-facing annular cutout and an inner surface situated between a front surface and a rear surface, the inner surface configured to seal against a reciprocating plunger and comprising at least one non-linear protrusion situated in a spaced relationship from the front and rear surfaces; and
an outer seal, disposed in the outwardly-facing annular cutout of the inner seal, wherein the outer seal is comprised of a different material than the inner seal;
in which the at least one hybrid seal of the monolithic piece is positioned adjacent to the junk ring.
2 . The plunger packing of claim 1 , in which the outer seal is made of an elastomeric material.
3 . The plunger packing of claim 2 , in which the inner seal comprises a polymer filled with aramid fibers.
4 . The plunger packing of claim 1 , in which a rear surface of the outer seal engages the junk ring.
5 . The plunger packing of claim 1 , in which the front surface of the inner seal engages the lantern ring.
6 . The plunger packing of claim 1 , in which:
the inner seal comprises a first homogenous material; and
the outer seal comprises a second homogenous material.
7 . The plunger packing of claim 1 in which no portion of the inner seal is covered in fabric.
8 . The plunger packing of claim 1 , in which:
a concave opening is formed in the outer seal;
a convex front surface is formed on the junk ring;
wherein the concave opening and the convex front surface are complementary.
9 . The plunger packing of claim 1 , in which:
the front surface of the inner seal is convex; and
a concave opening is formed on the lantern ring;
wherein the concave opening and the convex front surface are complementary.
10 . The plunger packing of claim 1 in which the outer seal comprises an O-ring.
11 . The plunger packing of claim 1 in which the outer seal is elastomeric.
12 . The plunger packing of claim 1 in which the at least one non-linear protrusion comprises a plurality of V-shaped extrusions formed on the inner surface of the inner seal.
13 . The plunger packing of claim 1 in which the at least one non-linear protrusion is curved without a sharp angle.
14 . The plunger packing of claim 1 wherein the at least one hybrid seal is characterized as a first hybrid seal, and further comprising:
a second hybrid seal, disposed between the junk ring and the first hybrid seal, the second hybrid seal comprising:
a second inner seal, the second inner seal having an outwardly-facing annular cutout; and
a second outer seal, disposed in the outwardly-facing annular cutout of the second inner seal, wherein the second outer seal is comprised of a different material than the second inner seal.
15 . The plunger packing of claim 14 , in which:
the outer seal of the first hybrid seal defines a concave cavity; and
the second inner seal comprises a convex surface;
in which the convex surface is installed within the concave cavity of the outer seal such that the first hybrid seal and the second hybrid seal are interlocked.
16 . The plunger packing of claim 15 , in which the convex surface of the second inner seal comprises a protrusion, corresponding to a relief cutout within the concave cavity of the outer seal of the first hybrid seal.
17 . The plunger packing of claim 14 , further comprising:
a third hybrid seal, disposed between the junk ring and the second hybrid seal, the third hybrid seal comprising:
a third inner seal, the third inner seal having an outwardly-facing annular cutout; and
a third outer seal, disposed in the outwardly-facing annular cutout of the third inner seal, wherein the third outer seal is comprised of a different material than the third inner seal.
18 . The plunger packing of claim 17 in which:
at least a portion of an inner surface of the second inner seal comprises a plurality of V-shaped extrusions; and
at least a portion of an inner surface of the third inner seal comprises a protrusion that is curved without a sharp angle.
19 . The plunger packing of claim 17 in which:
the second outer seal comprises an O-ring.
20 . The plunger packing of claim 1 in which the inner seal comprises:
a ring portion extending along a length of the inner seal from the front surface to the rear surface; and
a flange portion extending outwardly from the ring portion;
wherein the outwardly-facing annular cutout is adjacent to the flange portion and extends from the flange portion to the rear surface.
21 . The plunger packing of claim 1 , in which the outer seal is over-molded to the inner seal.
22 . The plunger packing of claim 1 , in which the outer seal is bonded directly to the inner seal.
23 . The plunger packing of claim 1 , in which the lantern ring is made of a same material as the inner seal; and in which the lantern ring is made of a polymer.
24 . The plunger packing of claim 1 , in which the lantern ring is made of a polymer filled with aramid fibers.
25 . The plunger packing of claim 1 , in which the lantern ring is made of an ultra-high-molecular-weight polyethylene material with a glass filler.
26 . The plunger packing of claim 1 , in which the at least one hybrid seal is one and only one hybrid seal.
27 . A fluid end, comprising:
a fluid end body comprising a fluid bore, the fluid bore configured to receive a plunger; and
the plunger packing of claim 1 ;
in which an outer surface of the inner seal faces an inner wall of the fluid bore.
28 . The fluid end of claim 27 further comprising a stuffing box disposed within the fluid end body, in which the plunger packing is disposed within the stuffing box.
29 . The fluid end of claim 27 , wherein:
a plunger is disposed within the fluid bore; and
no portion of an inner-most wall of the outer seal engages any portion of the plunger.
30 . A stuffing box configured for placement in a fluid bore of a fluid end body, the stuffing box configured to receive the plunger packing of claim 17 .