US 5,472,058 A · Rock bit with mechanical seal

Abstract

A mechanical seal for use in a rotary rock bit comprises a leg seal ring positioned within a recessed portion of a leg forming a seal cavity. The leg seal comprises one surface partially engaged by a resilient material and an opposite surface comprising a first sealing surface. The mechanical seal also comprises cone seal ring positioned within a portion of a cone forming the seal cavity. The cone seal comprises one surface positioned within and attached to a recessed portion of the cone and another surface comprising a second sealing surface engaging the first sealing surface. The portion of the leg seal ring engaged by the resilient material engages a back face of the leg which includes a ramp, serving to urge the first sealing surface against the adjacent second sealing surface and create a sealing engagement. The first and second sealing surfaces are made from different hard materials each having a similar hardness of greater than 1000, and each material selected has a Knoop hardness difference of about 400 or less. The first and second sealing surfaces may be formed from materials the same as or different than materials forming the leg seal ring and cone seal ring, respectively.

Claims24

Dependent claims

A rotary cone rock bit for drilling wells including a mechanical seal between a leg of the rock bit and a rotatable cone mounted on a journal bearing extending from the leg, the seal comprising:

a first seal ring statically sealed to the leg and having a sealing surface selected from the group of hard materials consisting of hard materials consisting of hardened metals, ceramics, and ceramic-metal composites;
a second seal ring statically sealed to the cone and having a sealing surface selected from the group consisting of hard materials consisting of hardened metals, ceramics, and ceramic-metal composites, wherein the sealing surface of the first seal ring and the sealing surface of the second seal ring each have a Knoop hardness greater than about 1000;
and
means for resiliently biasing the sealing surfaces toward each other for forming a dynamic seal.

1 more element

A rotary cone rock bit comprising:

a mechanical seal positioned in a seal cavity formed between a leg of the rock bit and a rotatable cone mounted on a journal bearing extending from the leg of the bit, the mechanical seal comprising:
a leg seal ring having a diameter fitting within the seal cavity, the leg seal ring comprising one surface at least partially engaged by a resilient material positioned adjacent to a face portion of the leg forming a ramp, and an opposite surface comprising a first sealing surface made from a hard material having a Knoop hardness in the range of from about 1000 to 4000;
and
a cone seal ring having a diameter fitting within the seal cavity, the cone seal ring comprising one surface positioned adjacent to a recessed portion of the cone, and an opposite surface comprising a second sealing surface made from a hard material different than that of the first sealing surface and having a Knoop hardness in the range of from 1000 to 4000, wherein the second sealing surface is positioned adjacent to the first sealing surface to effect a sealing engagement, and wherein the first and second sealing surfaces are pre-lapped prior to insertion of the leg seal ring into the seal cavity of the rotary cone rock bit for forming a seal between sealing surfaces.

1 more element

A rotary cone rock bit comprising:

a seal cavity formed between a leg of the rock bit and a rotatable cone mounted on a journal bearing extending from the leg of the bit;
a mechanical seal positioned within the seal cavity between the journal bearing and the cone, the mechanical seal comprising:
a leg seal ring having a diameter adapted to fit within a recessed portion of the leg forming the seal cavity, the leg seal ring comprising a first sealing surface of a material selected from the group of materials consisting of hardened metals, ceramics, and ceramic-metal composites, the material having a Knoop hardness in the range of from about 1000 to 4000;
a cone seal ring having a diameter adapted to fit within a recessed portion of the cone forming the seal cavity, the cone seal ring comprising one surface attached within a recessed portion of the cone and an opposite surface having a second sealing surface positioned adjacent to the first sealing surface, the second sealing surface of a material selected from the group of materials consisting of hardened metals, ceramics, and ceramic-metal composites, the leg and cone seal rings each .having sealing surfaces of different materials having a Knoop hardness in the range of from about 1000 to 4000, wherein the first and second sealing surface has a difference in Knoop hardness of less than 2000;
and
a resilient material at least partially engaging a surface of the leg seal ring opposite to the first sealing surface, the resilient material is positioned against a face portion of the leg for urging the first sealing surface against the second sealing surface to maintain the first and second sealing surfaces in sealing engagement.

3 more elements

A rotary cone rock bit comprising:

a seal cavity formed between a leg of the rock bit and a rotatable cone mounted on a journal bearing extending from the leg of the bit;
and
a mechanical seal positioned within the seal cavity between the journal bearing and the cone, the mechanical seal comprising:
a leg seal ring having a diameter adapted to fit within a recessed portion of the leg forming the seal cavity, the leg seal ring comprising a first sealing surface of a material different than the leg seal ring selected from the group of materials consisting of hardened metals, ceramics, and ceramic-metal composites;
a cone seal ring having a diameter adapted to fit within a recessed portion of the cone forming the seal cavity, the cone seal ring comprising one surface attached within a recessed portion of the cone and an opposite surface supporting a second sealing surface positioned adjacent to the first sealing surface, the second sealing surface is formed from a material different than the cone seal ring selected from the group of materials consisting of hardened metals, ceramics, and ceramic-metal composites, the first and second sealing surface each being made from a different material having a Knoop hardness in the range of from about 1000 to 4000, wherein the first and second sealing surface has a difference in Knoop hardness of less than 2000;
and
a resilient material at least partially engaging a surface of the leg seal ring opposite the first sealing surface, the resilient material being positioned against a face portion of the leg for urging the first sealing surface against the second sealing surface to maintain the first and second sealing surfaces in sealing engagement.

4 more elements

Dependencies are inferred from the claim text.

Rock bit with mechanical seal

Life of this patent

Rock bit with mechanical seal

Life of this patent

Abstract

Claims24