Title of Invention	SHAFT SEAL FOR A TRANSMISSION EXPANDER OR COMPRESSOR, AND TRANSMISSION EXPANDER OR COMPRESSOR HAVING A SHAFT SEAL
Abstract	A shaft seal for a transmission expander or compressor having one or more rotors (1) which rotates/rotate in a housing (20) and are arranged in a floating manner on a shaft (4) comprises a seal arrangement (10) having seal tips (15) which are attached on the hub (5) of the rotor (1) and are surrounded by a stationary sealing ring (11). The seal tips (15) are arranged in three seal sections, an annular chamber (12,12') being arranged between in each case two seal sections. The annular chamber (12) which faces the interior of the transmission expander or compressor is equipped with a feed means for a sealing gas, the pressure of which is higher than the pressure in the interior of the transmission expander or compressor. The annular chamber (12') which faces away from the interior of the transmission expander or compressor is provided with an extraction means for the sealing gas.

Title of Invention

SHAFT SEAL FOR A TRANSMISSION EXPANDER OR COMPRESSOR, AND TRANSMISSION EXPANDER OR COMPRESSOR HAVING A SHAFT SEAL

Abstract

A shaft seal for a transmission expander or compressor having one or more rotors (1) which rotates/rotate in a housing (20) and are arranged in a floating manner on a shaft (4) comprises a seal arrangement (10) having seal tips (15) which are attached on the hub (5) of the rotor (1) and are surrounded by a stationary sealing ring (11). The seal tips (15) are arranged in three seal sections, an annular chamber (12,12') being arranged between in each case two seal sections. The annular chamber (12) which faces the interior of the transmission expander or compressor is equipped with a feed means for a sealing gas, the pressure of which is higher than the pressure in the interior of the transmission expander or compressor. The annular chamber (12') which faces away from the interior of the transmission expander or compressor is provided with an extraction means for the sealing gas.

Full Text	FORM 2 THE PATENT ACT 1970 (39 of 1970) The Patents Rules, 2003 COMPLETE SPECIFICATION (See Section 10, and rule 13) TITLE OF INVENTION SHAFT SEAL FOR A TRANSMISSION EXPANDER OR COMPRESSOR, AND TRANSMISSION EXPANDER OR COMPRESSOR HAVING A SHAFT SEAL APPLICANT(S) a) Name b) Nationality c) Address : MAN TURBO AG :GERMAN Company :STEINBRINKSTRASSE 1 46145 OBERHAUSEN GERMANY 3. PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner in which it is to be performed : - The invention relates to a shaft seal for a transmission expander or a transmission compressor having the features of the precharacterizing clause of Patent Claim 1, and a transmission expander or a transmission compressor having a shaft seal having the features of the precharacterizing clause of Patent Claim 5. The sealing of the process space in the shaft region of a transmission expander or compressor belongs to the most important features for the reliable operation of a transmission machine. The reliable operation of a transmission machine has an even greater significance if the operation takes place with aggressive or toxic gases. In order to prevent gas escaping out of the machine region into the open, the configuration of the seal is decisive. The invention is therefore based on the object of improving the shaft seal of the generic type in such a way that the amount of sealing gas or the leakage is low and that the shaft seal is protected against corrosion. In a shaft seal of the generic type, the object is achieved by the characterizing features of Patent Claim 1. A transmission expander or compressor which is equipped with a shaft seal of this type is the subject matter of Patent Claim 5. Advantageous refinements of the invention are specified in the subclaims. The shaft seal which is designed according to the invention achieves the situation where part of the sealing gas flows into the interior of the machine and the other part of the sealing gas flows in the direction of the extraction means. As a result, the penetration of process gas into the seal is prevented. In order to keep these amounts of sealing gas or leakages small, a number of seal tips are arranged which are turned from solid material and which constrict the gap between the shaft and the seal as far as possible. In addition, in order to minimize the amounts of sealing gas or leakages, the surface opposite the seal tips is provided with a break-in coating. The advantage of this break-in coating consists, firstly, in the high temperature resistance of approximately 750°C and, secondly, in the very satisfactory corrosion resistance. -2- Moreover, an optimum relationship of erosion of the coating by solid particles in the sealing gas and in the wear of the seal tips is achieved by the composition of the break-in coating. One exemplary embodiment of the invention is shown in the drawing and will be explained in greater detail in the following text. In the drawing: Fig. 1 shows a longitudinal section through a transmission expander which is shown partially, and Fig. 2 shows the detail Z from Fig. 1. The transmission expander which is shown is a single-shaft expander of radial construction for relieving air, steam or combustible or toxic gases. The following embodiments also relate to multiple-shaft expanders and to transmission compressors of radial construction in single-shaft or multiple-shaft configurations. The expander comprises a rotor 1 which rotates in a housing 20. The housing 20 comprises an inflow part 2 and a rear wall 3. The expander drives a motor/generator directly or indirectly via a transmission (not shown) which is connected in between. Only one output shaft 4 of the output of the expander is visible in Fig. 1. The rotor 1 is arranged in a floating manner on the output shaft 4. To this end, a hub 5 of the rotor 1 is connected to the output shaft 4 via a central tie rod 6. The tie rod 6 penetrates the hub 5 of the rotor 1 and the output shaft 4. Here, the tie rod 6 engages with a thread into an internal thread in the output shaft 4 and is tensioned via a nut 7 in a break-in cap 8 of the rotor 1. The hub 5 of the rotor 1 and the output shaft 4 are provided in each case with a toothing system 9 on the end faces which lie opposite one another. The teeth of the toothing system 9 engage into one another and together form a toothing system of -3- the radial serration type. The torque is transmitted from the rotor 1 to the output shaft 4 by the toothing system 9 in conjunction with the central tie rod 6. The interior or process space of the expander is sealed with respect to the external atmosphere by a seal arrangement 10. The seal arrangement 10 is accommodated in a stationary sealing ring 11 which is connected to the rear wall 3 of the housing of the expander. The seal arrangement 10 which will be described in greater detail in the following text encloses a rearward extension of the hub 5 of the rotor 1, which rearward extension is configured as a journal 14. As a result of this arrangement, the toothing system 9 between the hub 5 of the rotor 1 and the output shaft 4 is moved outwards into the atmospheric region which surrounds the expander. The toothing system 9 therefore does not come into contact with the process gas in the interior of the expander. As a result, for the case where the expander is operated with aggressive media, there is no longer a risk that these media come into contact with the toothing system 9 as a result of leakage and lead to corrosion of the toothing system 9. The seal of the seal arrangement 10 is configured as a labyrinth seal in a triple configuration and comprises three seal sections which lie one behind another with respective seal tips 15. The seal tips 15 are attached to the hub 5 of the rotor 1 and are turned from solid material. An annular chamber 12,12' which is connected to a line 13,13' which is led to the outside is situated in each case between two seal sections. A sealing gas at a pressure which exceeds the pressure of the process gas in the interior of the expander is fed via the line 13 to the annular chamber 12 which faces the expander. Sealing gas is extracted via the line 13' from the annular chamber 12' which faces the toothing system 9 and faces away from the expander. This achieves the situation where part of the sealing gas flows in the direction of the rotor and the other part of the sealing gas flows in the direction of the extraction means, as a result of which penetration of process gas into the seal is prevented. -4- That seal face on the sealing ring 11 which lies opposite the seal tips 15 is coated with a break-in coating 16. The break-in coating 16 is an APS (air plasma spray) coating consisting of a sealing CoNiCrAlY adhesive layer and a porous CoNiCrAlY-BN-polyester upper layer. The two layers have the following chemical composition: adhesive layer: 32% Ni, 21% Cr, 8% Al, 0.4% Y, Co rest. upper layer: 25% Ni, 17% Cr, 6% Al, 0.4% Y, 63.6% boron nitride (BN), 15% polyester, Co rest. The adhesive layer serves for improved adhesion of the upper layer and for improved corrosion resistance of the coating. In order to optimize the break-in property, the porosity of the coating is also set in a targeted manner in addition to the hardness. The porosity is preferably to be 40%. The manufacturing process of the break-in coating 16 on the sealing ring 11 comprises the following steps: 1. Spraying on of the adhesive layer according to the APS process; 2. Spraying on of the upper layer consisting of CrNiCrAlY-BN-polyester according to the APS process; 3. Thermal treatment/annealing of the sealing ring 11, in order that the polyester component is outgassed and therefore the defined porosity is set. -5- WE CLAIM: 1. Shaft seal for a transmission expander or compressor having one or more rotors (1) which rotates/ rotate in a housing (20), each rotor (1) being arranged in a floating manner on a shaft (4) and being sealed by a seal arrangement (10) which is connected to the housing and comprises seal tips (15) which are attached on the shaft (4) or a hub (5) of the rotor (1) and are surrounded by a stationary sealing ring (11), characterized in that the seal tips (15) are arranged in three seal sections which lie behind one another, in that an annular chamber (12,12') is arranged between in each case two seal sections, in that the annular chamber (12) which faces the interior of the transmission expander or compressor is equipped with a feed means for a sealing gas, the pressure of which is higher than the pressure in the interior of the transmission expander or compressor, and in that the annular chamber (12') which faces away from the interior of the transmission expander or compressor is provided with an extraction means for the sealing gas. 2. Shaft seal according to Claim 1, characterized in that that sealing face of the stationary sealing ring (11) which lies opposite the seal tips (15) is provided with a break-in coating (16) which consists of a sealing adhesive layer made of CoNiCrAlY and a porous temperature-resistant and corrosion-resistant upper layer made of CoNiCrAlY + BN + polyester. 3. Shaft seal according to Claim 2, characterized in that the sealing ring (11) has a defined, adjustable porosity which is associated with a thermal treatment of the sealing ring (11) with out-gassing of the polyester component in the upper layer of the break-in coating. 4. Shaft seal according to one of Claims 1 to 3, characterized in that the seal tips (15) are turned from solid material. -6- 5. Transmission expander or compressor having a shaft seal according to Claims 1 to 4 and having one or more rotors (1) which rotates/ rotate in each case in a housing (20), each rotor (1) being arranged in a floating manner on a shaft (4) and a hub (5) of each rotor (1) and the associated shaft (4) being provided with a toothing system (9) which engages into one another, characterized in that the hub (5) of the rotor (1) is guided through the seal arrangement (10), and in that the toothing system (9) is provided outside the seal arrangement (10) of the transmission expander or compressor. Dated this 11th day of August, 2006 ABSTRACT A shaft seal for a transmission expander or compressor having one or more rotors (1) which rotates/rotate in a housing (20) and are arranged in a floating manner on a shaft (4) comprises a seal arrangement (10) having seal tips (15) which are attached on the hub (5) of the rotor (1) and are surrounded by a stationary sealing ring (11). The seal tips (15) are arranged in three seal sections, an annular chamber (12, 12') being arranged between in each case two seal sections. The annular chamber (12) which faces the interior of the transmission expander or compressor is equipped with a feed means for a sealing gas, the pressure of which is higher than the pressure in the interior of the transmission expander or compressor. The annular chamber (12') which faces away from the interior of the transmission expander or compressor is provided with an extraction means for the sealing gas. (Fig- 2) To, The Controller of Patents The Patent Office Mumbai. -8-

Full Text

FORM 2
THE PATENT ACT 1970 (39 of 1970)
The Patents Rules, 2003 COMPLETE SPECIFICATION
(See Section 10, and rule 13)
TITLE OF INVENTION
SHAFT SEAL FOR A TRANSMISSION EXPANDER OR COMPRESSOR, AND
TRANSMISSION EXPANDER OR COMPRESSOR HAVING A SHAFT SEAL

APPLICANT(S)
a) Name
b) Nationality
c) Address

: MAN TURBO AG :GERMAN Company :STEINBRINKSTRASSE 1 46145 OBERHAUSEN GERMANY

3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -

The invention relates to a shaft seal for a transmission expander or a transmission compressor having the features of the precharacterizing clause of Patent Claim 1, and a transmission expander or a transmission compressor having a shaft seal having the features of the precharacterizing clause of Patent Claim 5.
The sealing of the process space in the shaft region of a transmission expander or compressor belongs to the most important features for the reliable operation of a transmission machine. The reliable operation of a transmission machine has an even greater significance if the operation takes place with aggressive or toxic gases. In order to prevent gas escaping out of the machine region into the open, the configuration of the seal is decisive.
The invention is therefore based on the object of improving the shaft seal of the generic type in such a way that the amount of sealing gas or the leakage is low and that the shaft seal is protected against corrosion.
In a shaft seal of the generic type, the object is achieved by the characterizing features of Patent Claim 1. A transmission expander or compressor which is equipped with a shaft seal of this type is the subject matter of Patent Claim 5. Advantageous refinements of the invention are specified in the subclaims.
The shaft seal which is designed according to the invention achieves the situation where part of the sealing gas flows into the interior of the machine and the other part of the sealing gas flows in the direction of the extraction means. As a result, the penetration of process gas into the seal is prevented. In order to keep these amounts of sealing gas or leakages small, a number of seal tips are arranged which are turned from solid material and which constrict the gap between the shaft and the seal as far as possible. In addition, in order to minimize the amounts of sealing gas or leakages, the surface opposite the seal tips is provided with a break-in coating. The advantage of this break-in coating consists, firstly, in the high temperature resistance of approximately 750°C and, secondly, in the very satisfactory corrosion resistance.
-2-

Moreover, an optimum relationship of erosion of the coating by solid particles in the sealing gas and in the wear of the seal tips is achieved by the composition of the break-in coating.
One exemplary embodiment of the invention is shown in the drawing and will be explained in greater detail in the following text. In the drawing:
Fig. 1 shows a longitudinal section through a transmission expander which is
shown partially, and
Fig. 2 shows the detail Z from Fig. 1.
The transmission expander which is shown is a single-shaft expander of radial construction for relieving air, steam or combustible or toxic gases. The following embodiments also relate to multiple-shaft expanders and to transmission compressors of radial construction in single-shaft or multiple-shaft configurations.
The expander comprises a rotor 1 which rotates in a housing 20. The housing 20 comprises an inflow part 2 and a rear wall 3. The expander drives a motor/generator directly or indirectly via a transmission (not shown) which is connected in between.
Only one output shaft 4 of the output of the expander is visible in Fig. 1. The rotor 1 is arranged in a floating manner on the output shaft 4. To this end, a hub 5 of the rotor 1 is connected to the output shaft 4 via a central tie rod 6. The tie rod 6 penetrates the hub 5 of the rotor 1 and the output shaft 4. Here, the tie rod 6 engages with a thread into an internal thread in the output shaft 4 and is tensioned via a nut 7 in a break-in cap 8 of the rotor 1.
The hub 5 of the rotor 1 and the output shaft 4 are provided in each case with a toothing system 9 on the end faces which lie opposite one another. The teeth of the toothing system 9 engage into one another and together form a toothing system of
-3-

the radial serration type. The torque is transmitted from the rotor 1 to the output shaft 4 by the toothing system 9 in conjunction with the central tie rod 6.
The interior or process space of the expander is sealed with respect to the external atmosphere by a seal arrangement 10. The seal arrangement 10 is accommodated in a stationary sealing ring 11 which is connected to the rear wall 3 of the housing of the expander.
The seal arrangement 10 which will be described in greater detail in the following text encloses a rearward extension of the hub 5 of the rotor 1, which rearward extension is configured as a journal 14. As a result of this arrangement, the toothing system 9 between the hub 5 of the rotor 1 and the output shaft 4 is moved outwards into the atmospheric region which surrounds the expander. The toothing system 9 therefore does not come into contact with the process gas in the interior of the expander. As a result, for the case where the expander is operated with aggressive media, there is no longer a risk that these media come into contact with the toothing system 9 as a result of leakage and lead to corrosion of the toothing system 9.
The seal of the seal arrangement 10 is configured as a labyrinth seal in a triple configuration and comprises three seal sections which lie one behind another with respective seal tips 15. The seal tips 15 are attached to the hub 5 of the rotor 1 and are turned from solid material. An annular chamber 12,12' which is connected to a line 13,13' which is led to the outside is situated in each case between two seal sections. A sealing gas at a pressure which exceeds the pressure of the process gas in the interior of the expander is fed via the line 13 to the annular chamber 12 which faces the expander. Sealing gas is extracted via the line 13' from the annular chamber 12' which faces the toothing system 9 and faces away from the expander. This achieves the situation where part of the sealing gas flows in the direction of the rotor and the other part of the sealing gas flows in the direction of the extraction means, as a result of which penetration of process gas into the seal is prevented.
-4-

That seal face on the sealing ring 11 which lies opposite the seal tips 15 is coated with a break-in coating 16. The break-in coating 16 is an APS (air plasma spray) coating consisting of a sealing CoNiCrAlY adhesive layer and a porous CoNiCrAlY-BN-polyester upper layer. The two layers have the following chemical composition: adhesive layer: 32% Ni, 21% Cr, 8% Al, 0.4% Y, Co rest.
upper layer: 25% Ni, 17% Cr, 6% Al, 0.4% Y, 63.6% boron nitride (BN), 15% polyester, Co rest.
The adhesive layer serves for improved adhesion of the upper layer and for improved corrosion resistance of the coating. In order to optimize the break-in property, the porosity of the coating is also set in a targeted manner in addition to the hardness. The porosity is preferably to be 40%.
The manufacturing process of the break-in coating 16 on the sealing ring 11 comprises the following steps:
1. Spraying on of the adhesive layer according to the APS process;
2. Spraying on of the upper layer consisting of CrNiCrAlY-BN-polyester according to the APS process;
3. Thermal treatment/annealing of the sealing ring 11, in order that the polyester component is outgassed and therefore the defined porosity is set.
-5-

WE CLAIM:
1. Shaft seal for a transmission expander or compressor having one or more rotors (1) which rotates/ rotate in a housing (20), each rotor (1) being arranged in a floating manner on a shaft (4) and being sealed by a seal arrangement (10) which is connected to the housing and comprises seal tips (15) which are attached on the shaft (4) or a hub (5) of the rotor (1) and are surrounded by a stationary sealing ring (11), characterized in that the seal tips (15) are arranged in three seal sections which lie behind one another, in that an annular chamber (12,12') is arranged between in each case two seal sections, in that the annular chamber (12) which faces the interior of the transmission expander or compressor is equipped with a feed means for a sealing gas, the pressure of which is higher than the pressure in the interior of the transmission expander or compressor, and in that the annular chamber (12') which faces away from the interior of the transmission expander or compressor is provided with an extraction means for the sealing gas.
2. Shaft seal according to Claim 1, characterized in that that sealing face of the stationary sealing ring (11) which lies opposite the seal tips (15) is provided with a break-in coating (16) which consists of a sealing adhesive layer made of CoNiCrAlY and a porous temperature-resistant and corrosion-resistant upper layer made of CoNiCrAlY + BN + polyester.
3. Shaft seal according to Claim 2, characterized in that the sealing ring (11) has a defined, adjustable porosity which is associated with a thermal treatment of the sealing ring (11) with out-gassing of the polyester component in the upper layer of the break-in coating.
4. Shaft seal according to one of Claims 1 to 3, characterized in that the seal tips (15) are turned from solid material.
-6-

5. Transmission expander or compressor having a shaft seal according to Claims 1 to 4 and having one or more rotors (1) which rotates/ rotate in each case in a housing (20), each rotor (1) being arranged in a floating manner on a shaft (4) and a hub (5) of each rotor (1) and the associated shaft (4) being provided with a toothing system (9) which engages into one another, characterized in that the hub (5) of the rotor (1) is guided through the seal arrangement (10), and in that the toothing system (9) is provided outside the seal arrangement (10) of the transmission expander or compressor.
Dated this 11th day of August, 2006

ABSTRACT
A shaft seal for a transmission expander or compressor having one or more rotors (1) which rotates/rotate in a housing (20) and are arranged in a floating manner on a shaft (4) comprises a seal arrangement (10) having seal tips (15) which are attached on the hub (5) of the rotor (1) and are surrounded by a stationary sealing ring (11). The seal tips (15) are arranged in three seal sections, an annular chamber (12, 12') being arranged between in each case two seal sections. The annular chamber (12) which faces the interior of the transmission expander or compressor is equipped with a feed means for a sealing gas, the pressure of which is higher than the pressure in the interior of the transmission expander or compressor. The annular chamber (12') which faces away from the interior of the transmission expander or compressor is provided with an extraction means for the sealing gas.
(Fig- 2)
To,
The Controller of Patents
The Patent Office
Mumbai.
-8-

SHAFT SEAL FOR A TRANSMISSION EXPANDER OR COMPRESSOR, AND TRANSMISSION EXPANDER OR COMPRESSOR HAVING A SHAFT SEAL

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