Shaft seal

Claim 2

A shaft seal interposed between relatively rotatable shaft means and casing wall means through which said shaft means extends, said casing wall means having a first pressure zone on one side thereof and a second pressure zone on the other side thereof, said shaft seal comprising: a. first sealing means mounted in fixed relationship to said shaft means and forming first and second sealing surface areas each surrounding said shaft means; b. second sealing means mounted in fixed relationship to said casing wall means and forming first and second sealing surface areas, said first and second surface areas formed by said second sealing means mating in sealing engagement with said first and second sealing surface areas of said first sealing means, respectively; c. means forming a buffer fluid compartment communicating with said first and second sealing means at their points of sealing engagement; d. first means communicating with said first pressure zone; e. second means communicating with said second pressure zone; and f. means responsive to said first and second communicating means for applying to buffer fluid within said compartment a pressure which at least substantially equals the greater of the pressures in said first and second pressure zones, thereby to inhibit passage of material along said shaft means from either of said pressure zones to the other.

Claim 3

A shaft seal according to claim 1 wherein said pressure applying means is responsive to the pressures in both said first and second pressure zones.

Claim 4

A shaft seal according to claim 1 wherein said pressure applying means comprises: a. means forming a hermetically sealed expansible chamber communicating with said buffer fluid compartment; and b. means responsive to both the pressure in said first pressure zone and the pressure in said second pressure zone for applying to said expansible chamber and thereby to said compartment a pressure at least substantially equaling the greater of either the pressure in said first pressure zone or the pressure in said second pressure zone.

Claim 5

A shaft seal according to claim 3 wherein said pressure applying means further comprises means for constantly applying pressure to said expansible chamber and thereby to said compartment in addition to the pressure applied thereto by said means responsive to the pressures in said first and second pressure zones, whereby the pressure applied to said compartment exceeds the greater of either the pressure in said first pressure zone or the pressure in said second pressure zone.

Claim 6

A shaft seal according to claim 3 wherein said expansible chamber comprises a buffer fluid reservoir.

Claim 7

A shaft seal according to claim 1 wherein said means responsive to said first and second communicating means is in hermetically sealed fluid connection with said buffer fluid compartment.

Claim 8

In a Rankine cycle system including an expander having means forming a working fluid chamber and a rotary shaft extending from said working fluid chamber into an environmental zone, wherein the pressure in said working fluid chamber rises above environmental zone pressure during certain conditions and drops below environmental zone pressure during certain other conditions, a shaft seal comprising: a. a first sealing means on said shaft in fixed, fluid tight relationship thereto and having first and second sealing surface areas surrounding said shaft; b. second sealing means in fixed, fluid tight relationship to said means forming said working fluid chamber and having first and second sealing surface areas in sealing engagement with said first and second sealing surface areas, respectively, of said first sealing means; c. means forming a buffer fluid compartment in communication with said first and second sealing means at their points of engagement for maintaining a supply of buffer fluid at said points of engagement; and d. means in hermetically sealed fluId communication with said compartment constantly applying pressure to buffer fluid therein which at least equals the greater of either the pressure in said working fluid chamber or the pressure in said environmental zone, said pressure being applied during both operating and non-operating conditions of the Rankine cycle system, thereby to eliminate the tendency of material to pass along said shaft from said working fluid chamber into said environmental zone when pressure in said working fluid chamber is above environmental zone pressure and from said environmental zone into said working fluid chamber when pressure in said working fluid chamber is below environmental zone pressure.

Claim 9

In a Rankine cycle system including an expander having means forming a working fluid chamber and a rotary shaft extending from said working fluid chamber into an environmental zone, wherein the pressure in said working fluid chamber rises above environmental zone pressure during certain conditions and drops below environmental zone pressure during certain other conditions, a shaft seal comprising: a. a first sealing means on said shaft in fixed, fluid tight relationship thereto and having first and second sealing surface areas surrounding said shaft; b. second sealing means in fixed, fluid tight relationship to said means forming said working fluid chamber and having first and second sealing surface areas in sealing engagement with said first and second sealing surface areas, respectively, of said first sealing means; c. means forming a buffer fluid compartment in communication with said first and second sealing means at their points of engagement for maintaining a supply of buffer fluid at said points of engagement; and d. means in hermetically sealed fluId communication with said compartment constantly applying pressure to buffer fluid therein which at least equals the greater of either the pressure in said working fluid chamber or the pressure in said environmental zone, said pressure being applied during both operating and non-operating conditions of the Rankine cycle system, thereby to eliminate the tendency of material to pass along said shaft from said working fluid chamber into said environmental zone when pressure in said working fluid chamber is above environmental zone pressure and from said environmental zone into said working fluid chamber when pressure in said working fluid chamber is below environmental zone pressure.

Claim 10

In a Rankine cycle system according to claim 7 a shaft seal wherein said pressure applying means applies to buffer fluid within said compartment a pressure greater than either the pressure of said working fluid chamber or the pressure of said environmental zone.

Claim 11

In a Rankine cycle system according to claim 7 a shaft seal wherein: a. said first sealing means comprises an annular flange surrounding said rotary shaft; b. said second sealing means comprises a pair of annular sealing surfaces for sealing engagement with opposite sides of said annular flange; and c. said buffer fluid compartment surrounds said annular flange along and between the points of engagement of said annular flange with said pair of annular sealing surfaces.

Claim 12

In a Rankine cycle system according to claim 9 a shaft seal further comprising means forming a fluid inlet and a fluid outlet for said buffer fluid compartment wherein said buffer fluid compartment surrounds said annular flange, eccentrically thereof, whereby rotary movement of said annular flange within said buffer fluid compartment during operation of the Rankine cycle system produces a pumping action for drawing buffer fluid into said compartment through said inlet and expelling buffer fluid from said compartment and through said outlet.

Claim 13

In a Rankine cycle system according to claim 10 a shaft seal further comprising: a. means connecting said inlet and outlet means to form a closed loop in which said buffer fluid travels; and b. reservoir means communicating with said closed loop for providing a continuing supply of buffer fluid to replenish any buffer fluid which passes from said compartment into said working fluid chamber or said environmental zone.

Claim 14

In a Rankine cycle system according to claim 11 a shaft seal wherein: a. said reservoir means comprises a flexible, hermetically sealed buffer fluid confining means; and b. said means constantly applying pressure applies pressure to said flexible, hermetically sealed fluid confining means for exerting pressure on buffer fluid in said compartment.

Claim 15

In a Rankine cycle system according to claim 10 a shaft seal wherein said means constantly applying pressure is responsive to the pressure in said environmental zone and the pressure in said working fluid chamber.

Claim 16

In a Rankine cycle system according to claim 10 a shaft seal wherein said means constantly applying pressure comprises: a. spring means for continuously applying pressure to said buffer fluid confining means; and b. means responsive to the pressure in said working fluid chamber and the pressure in said environmental zone for applying to said buffer fluid confining means a pressure in addition to pressure applied thereto by said spring means, which at least substantially equals the higher of the pressures in the aforesaid zones,whereby the buffer fluid pressure in said compartment always exceeds both the pressure in said working fluid chamber and the pressure in said zone of environmental pressure to prohibit passage of material along said shaft from said zone into said working fluid chamber or from said working fluid chamber into said zone.

Claim 17

In a Rankine cycle system according to claim 7 a shaft seal further comprising: a. fluid conduit means having both inlet and outlet means connected to said buffer fluid compartment to form a closed loop; and b. means forming a pump for causing fluid in said compartment to travel through said closed loop during rotation of said shaft.

Claim 18

In a Rankine cycle system according to claim 7, a shaft seal wherein said pressure applying means comprises: a. first means communicating with pressure external of said chamber; b. second means communicating with pressure internal of said chamber; and c. means responsive to said first and second communicating means for applying to buffer fluid within said compartment a pressure at least substantially equal to the greater of either said first or second pressure levels.

Claim 19

In a Rankine cycle system including an expander casing means forming a chamber to contain fluid lubricant and organic Rankine cycle working fluid, the interior and exterior of said chamber being characterized by different pressure levels, and rotary drive shaft means extending through said casing, a shaft seal comprising: a. first sealing means in fixed, fluid tight relationship to said shaft means and having a first surface portion and a second surface portion; b. second sealing means in fixed, fluid tight relationship to said expander casing means and in sealing engagement with both said first and second surface portions of said first sealing means; c. means forming a buffer fluid compartment in communication with said first and second sealing means at their points of sealing engagement for maintaining a supply of buffer fluid at said points of engagement; d. hermetically sealed compressible reservoir means in fluid communication with said compartment; e. first means for continuously applying pressure to said reservoir means and thereby to buffer fluid within said compartment; and f. second means for continuously applying pressure to said reservoir means to thereby continuously pressurize buffer fluid within said compartment in addition to pressure applied thereto by said first pressure applying means, the magnitude of which is functionally related to the greater of either the pressure internal of said chamber or the pressure external of said chamber.

Claim 20

In a Rankine cycle system including an expander casing means forming a chamber to contain fluid lubricant and organic Rankine cycle working fluid, the interior and exterior of said chamber being characterized by different pressure levels, and rotary drive shaft means extending through said casing, a shaft seal comprising: a. first sealing means in fixed, fluid tight relationship to said shaft means and having a first surface portion and a second surface portion; b. second sealing means in fixed, fluid tight relationship to said expander casing means and in sealing engagement with both said first and second surface portions of said first sealing means; c. means forming a buffer fluid compartment in communication with said first and second sealing means at their points of sealing engagement for maintaining a supply of buffer fluid at said points of engagement; d. hermetically sealed compressible reservoir means in fluid communication with said compartment; e. first means for continuously applying pressure to said reservoir means and thereby to buffer fluid within said compartment; and f. second means for continuously applying pressure to said reservoir means to thereby continuously pressurize buffer fluid within said compartment in addition to pressure applied thereto by said first pressure applying means, the magnitude of which is functionally related to the greater of either the pressure internal of said chamber or the pressure external of said chamber.

Claim 21

In a Rankine cycle system according to claim 17 a shaft seal wherein said second pressure applying means applies pressure to said buffer fluid which is at least substantially as great as the greater of either the pressure within said chamber or the pressure without said chamber, whereby the pressure applied to said buffer fluid within said compartment is always greater than either the pressure within said chamber or the pressure without said chamber.

Claim 22

In a Rankine cycle system according to claim 18, a shaft seal wherein said compressible reservoir is for buffer fluid.

Claim 23

In a Rankine cycle system according to claim 19 a shaft seal further comprising means for indicating the amount of buffer fluid in said reservoir.

Claim 24

In a Rankine cycle system according to claim 17, a shaft seal wherein said second pressure applying means comprises: a. first means communicating with pressure external of said chamber for applying to said reservoir means a first pressure level having a magnitude substantially equal to said external pressure; b. second means communicating with pressure internal of said chamber for applying to said reservoir means a second pressure level having a magnitude substantially equal to said internal pressure; and c. means associated with said reservoir means and responsive to said first and second communicating means for applying to buffer fluid within said compartment a pressure at least substantially equal to the greater of either the pressure internal of said chamber or the pressure external of said chamber.

Claim 25

A shaft seal interposed between relatively rotatable shaft means and casing wall means through which said shaft means extends, said casing wall means having a first pressure zone on one side theReof and a second pressure zone on the other side thereof, the pressure in said first pressure zone being greater than the pressure in said second pressure zone under some conditions and less than the pressure in said second zone under other conditions, said shaft seal comprising: a. first sealing means mounted in fixed relationship to said shaft means and forming first and second sealing surface areas each surrounding said shaft means; b. second sealing means mounted in fixed relationship to said casing wall means and forming first and second sealing surface areas, said first and second surface areas formed by said second sealing means mating in sealing engagement with said first and second sealing surface areas of said first sealing means, respectively; c. means forming a buffer fluid compartment communicating with said first and second sealing means at their points of sealing engagement; and d. means in hermetically sealed fluid communication with said compartment for continuously applying to buffer fluid within said compartment, under all conditions, a pressure which at least substantially equals the greater of the pressures in said first and second pressure zones, thereby to inhibit passage of material along said shaft means from either of said pressure zones to the other under all conditions.

Claim 26

A shaft seal interposed between relatively rotatable shaft means and casing wall means through which said shaft means extends, said casing wall means having a first pressure zone on one side theReof and a second pressure zone on the other side thereof, the pressure in said first pressure zone being greater than the pressure in said second pressure zone under some conditions and less than the pressure in said second zone under other conditions, said shaft seal comprising: a. first sealing means mounted in fixed relationship to said shaft means and forming first and second sealing surface areas each surrounding said shaft means; b. second sealing means mounted in fixed relationship to said casing wall means and forming first and second sealing surface areas, said first and second surface areas formed by said second sealing means mating in sealing engagement with said first and second sealing surface areas of said first sealing means, respectively; c. means forming a buffer fluid compartment communicating with said first and second sealing means at their points of sealing engagement; and d. means in hermetically sealed fluid communication with said compartment for continuously applying to buffer fluid within said compartment, under all conditions, a pressure which at least substantially equals the greater of the pressures in said first and second pressure zones, thereby to inhibit passage of material along said shaft means from either of said pressure zones to the other under all conditions.