Disperser seal and method

Claim 2

A seal for a shaft of a disperser crusher adapted to pulverize hot coal particles that are conveyed by hot gases to the crusher, said crusher being in a casing having a wall through which the shaft extends to a drive motor, said seal adapted to maintain a higher than atmospheric pressure established by the hot gases within the casing, comprising interior and exterior packings enclosed within interior and exterior packing housings fixed on and respectively inside and outside of said casing wall and each packing in abutting relationship with a high temperature resistant low friction coefficient sleeve on said shaft, means for urging each of the packings against said sleeve on said shaft to establish a seal between said sleeve and the casing wall, said packings being fabricated of a material capable of withstanding the elevated temperatures on the surface of the shaft, conduit means for supplying gas to the interior packing in a direction to urge the interior packing longitudinally of the shaft away from the casing wall, said conduit means in fluid flow relationship with means for establishing a tortuous path for the coal particles from the interior of the casing to the interior packing, wherein the tortuous path terminates in a generally annular nozzle for the gas, said nozzle directing the gas back over the interior packing housing toward a casing wall portion adjacent the seal, said gas being inert with the coal particles and having a pressure greater than the pressure inside of the casing whereby coal particles are continuously biased away from the packings by the gas emitted from the nozzle.

Claim 3

The seal of claim 1 wherein the area of the interior packing is less than the area of the exterior packing in planes at right angles to the shaft radius and longitudinal axis so that a greater compressive force, in the radial direction of the shaft, is applied to the exterior packing than to the interior packing to tend to prevent coal particles from migrating from the casing to the interior packing.

Claim 4

The seal of claim 1 wherein the conduit means and the means for urging the packings against the sleeve include a pair of split body mounting plates secured to the casing exterior and to each other, and further including a split ring secured to the plates urging the exterior packing toward the interior of the casing against a wall of the plates parallel to a wall of the casing.

Claim 5

The seal of claim 1 wherein the packings are graphite.

Claim 6

A seal as claimed in claim 1 wherein the sleeve on the shaft is a ceramic sleeve fixed on and integral with the shaft at the seal.

Claim 7

In combination, a disperser crusher for pulverizing hot coal particles that are conveyed to the crusher by hot gases, a casing for the crusher, a shaft extending through the casing wall to a drive motor, a seal for the shaft including exterior and interior packing housing portions on opposite sides of the casing wall, each of said housing portions having seals adapted to maintain a higher than atmospheric pressure established by the hot gases within the casing, each of said seals including: interior and exterior packings respectively inside and outside of said casing wall in said interior and exterior housing portions respectively and each in abutting relationship with the shaft, means for urging each of the packings against the shaft to establish a seal between the shaft and the casing, said packings being fabricated of a material capable of withstanding the temperature on the surface of the shaft, conduit means for supplying a gas to the interior packing in a direction to urge the interior packing longitudinally of the shaft away from the casing wall, said conduit means in fluid flow relationship with means for establishing a tortuous path for the coal particles from the interior of the casing to the interior packing wherein the tortuous path terminates in a generally annular nozzle for the gas, said nozzle directing the gas back over the interior packing housing toward a casing wall portion adjacent the seal, said gas being inert with the coal particles and having a pressure greater than the pressure inside of the casing whereby coal particles are continually biased away from the seals by the gas emitted from the nozzle.

Claim 8

In combination, a disperser crusher for pulverizing hot coal particles that are conveyed to the crusher by hot gases, a casing for the crusher, a shaft extending through the casing wall to a drive motor, a seal for the shaft including exterior and interior packing housing portions on opposite sides of the casing wall, each of said housing portions having seals adapted to maintain a higher than atmospheric pressure established by the hot gases within the casing, each of said seals including: interior and exterior packings respectively inside and outside of said casing wall in said interior and exterior housing portions respectively and each in abutting relationship with the shaft, means for urging each of the packings against the shaft to establish a seal between the shaft and the casing, said packings being fabricated of a material capable of withstanding the temperature on the surface of the shaft, conduit means for supplying a gas to the interior packing in a direction to urge the interior packing longitudinally of the shaft away from the casing wall, said conduit means in fluid flow relationship with means for establishing a tortuous path for the coal particles from the interior of the casing to the interior packing wherein the tortuous path terminates in a generally annular nozzle for the gas, said nozzle directing the gas back over the interior packing housing toward a casing wall portion adjacent the seal, said gas being inert with the coal particles and having a pressure greater than the pressure inside of the casing whereby coal particles are continually biased away from the seals by the gas emitted from the nozzle.

Claim 9

The combination of claim 6 wherein the area of the interior packing is less than the area of the exterior packing in planes at right angles to the shaft radius and longitudinal axis so that a greater compressive force, in the radial direction of the shaft, is applied to the exterior packing than to the interior packing to tend to prevent coal particles from migrating from the casing to the interior packing.

Claim 10

The combination of claim 6 wherein the conduit means and the means for urging the packings against the sleeve includes a pair of split body mounting plates secured to the casing exterior and to each other, and further including a split ring secured to the plates urging the exterior packing toward the interior of the casing against a wall of the plates parallel to a wall of the casing.

Claim 11

The combination of claim 6 wherein the packings are graphite.

Claim 12

The combination of claim 6 further including a source of superheated steam connected in fluid flow relation with the conduit means.

Claim 13

The combination of claim 6 wherein the shaft includes a ceramic outer layer abutting against the packings.

Claim 14

A seal for a shaft of a disperser crusher adapted to pulverize hot coal particles that are conveyed by hot gases to the crusher, said crusher being in a casing having a wall through which the shaft extends to a drive motor, said seal adapted to maintain a higher than atmospheric pressure established by the hot gases within the casing comprising interior and exterior packing means enclosed within interior and exterior packing housings respectively inside and outside of said casing wall and each packing means in abutting relationship with a high temperature resistant sleeve on said shaft, means for urging each of said packing means against said sleeve to establish a seal between said sleeve and the casing, said packing means being fabricated of a material capable of withstanding the temperature on the surface of the shaft, a conduit means for supplying gas to the interior packing means in a direction to urge the packing means longitudinally of the shaft away from the casing wall, said conduit means in fluid flow relationship with means for establishing a tortuous path for the coal particles from the interior of the casing to the packing means, wherein the tortuous path terminates in a generally annular nozzle for the gas, said nozzle directing the gas back over the interior packing housing toward a casing wall portion adjacent the seal, said gas being inert with the coal particles and having a pressure greater than the pressure inside of the casing whereby coal particles are continually biased away from the seals by the gas emitted from the nozzle.

Claim 15

A seal for a shaft of a disperser crusher adapted to pulverize hot coal particles that are conveyed by hot gases to the crusher, said crusher being in a casing having a wall through which the shaft extends to a drive motor, said seal adapted to maintain a higher than atmospheric pressure established by the hot gases within the casing comprising interior and exterior packing means enclosed within interior and exterior packing housings respectively inside and outside of said casing wall and each packing means in abutting relationship with a high temperature resistant sleeve on said shaft, means for urging each of said packing means against said sleeve to establish a seal between said sleeve and the casing, said packing means being fabricated of a material capable of withstanding the temperature on the surface of the shaft, a conduit means for supplying gas to the interior packing means in a direction to urge the packing means longitudinally of the shaft away from the casing wall, said conduit means in fluid flow relationship with means for establishing a tortuous path for the coal particles from the interior of the casing to the packing means, wherein the tortuous path terminates in a generally annular nozzle for the gas, said nozzle directing the gas back over the interior packing housing toward a casing wall portion adjacent the seal, said gas being inert with the coal particles and having a pressure greater than the pressure inside of the casing whereby coal particles are continually biased away from the seals by the gas emitted from the nozzle.

Claim 16

A seal as claimed in claims 1 or 6 or 12, wherein the nozzle is a reentrant nozzle extending from the shaft over a portion of the interior seal housing portion toward the casing wall.

Claim 17

A seal as claimed in claims 1 or 6 or 12, wherein said nozzle is an annulus formed between the inner housing and an annular ring fixed to and rotating with the shaft adjacent said inner housing.

Claim 18

A seal as claimed in claim 14 wherein the annular ring is L-shaped having a portion extending axially of the shaft over the inner housing to form an annular reentrant nozzle.