Patents by Inventor Nikola Rudi Stosic
Nikola Rudi Stosic has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9714572Abstract: A reduced noise screw expander is described, which comprises a main rotor and a gate rotor each having an ‘N’ profile. The rotors are designed so that the torque on the gate rotor caused by pressure forces is in the same direction as the torque on the gate rotor caused by frictional drag forces. A method of designing a screw machine exhibiting reduced noise is also described. The screw machine has two or more rotors having an ‘N’ profile, and the method involves determining a ratio r/r1, where r is the main rotor addendum and r1 is the radius of the rack round side, and ensuring that this ratio is greater than 1.1 where the screw machine is to be a screw compressor or less than or equal to 1.1 where the screw machine is to be a screw expander.Type: GrantFiled: April 3, 2013Date of Patent: July 25, 2017Assignee: The City UniversityInventor: Nikola Rudi Stosic
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Patent number: 9097143Abstract: A method, and associated apparatus, for generating power from medium temperature heat sources in the range of 200° to 700° C. with improved efficiency compared to systems operating on a Rankine cycle in which the working fluid is condensed at the same temperature. Water is heated in a boiler (11) with heat from the heat source A, (22) which may be a stream of exhaust gases (22), in order to generate wet steam having a dryness fraction in the range of 0.10 to 0.90 (10% to 90% dry). The wet steam is expanded to generate power in a positive displacement steam expander (21) such as a twin screw expander. The expanded steam is condensed at a temperature in the range of 70° C. to 120° C., and the condensed steam is returned to the boiler. The expanded steam may be condensed in the boiler of an Organic Rankine Cycle (22) to provide additional power, or by heat exchange with a heater of a heating system to provide a Combined Heat and cycle, thereby further improving the cycle efficiency.Type: GrantFiled: February 6, 2009Date of Patent: August 4, 2015Assignee: CITY UNIVERSITYInventors: Ian Kenneth Smith, Nikola Rudi Stosic
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Publication number: 20150086406Abstract: A reduced noise screw expander is described, which comprises a main rotor and a gate rotor each having an ‘N’ profile. The rotors are designed so that the torque on the gate rotor caused by pressure forces is in the same direction as the torque on the gate rotor caused by frictional drag forces. A method of designing a screw machine exhibiting reduced noise is also described. The screw machine has two or more rotors having an ‘N’ profile, and the method involves determining a ratio r/r1, where r is the main rotor addendum and r1 is the radius of the rack round side, and ensuring that this ratio is greater than 1.1 where the screw machine is to be a screw compressor or less than or equal to 1.1 where the screw machine is to be a screw expander.Type: ApplicationFiled: April 3, 2013Publication date: March 26, 2015Inventor: Nikola Rudi Stosic
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Publication number: 20130052072Abstract: A screw machine for use with a working fluid with a liquid phase present comprises rotors having meshed, lubricated helical formations. The rotors have an ‘N’ profile as disclosed in WO 97/43550. In use, lubrication of the helical formations of the rotors and optionally of the rotor bearings is achieved substantially exclusively with the liquid phase of the working fluid.Type: ApplicationFiled: February 14, 2011Publication date: February 28, 2013Applicant: THE CITY UNIVERSITYInventors: Ian Kenneth Smith, Nikola Rudi Stosic
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Publication number: 20120312009Abstract: A vapour power generating system including a closed circuit for a working fluid, and includes a heat exchanger assembly for heating the fluid under pressure with heat from the source, a separator for separating the vapour phase of the heated fluid from the liquid phase thereof, an expander for expanding the vapour to generate power, a condenser for condensing the outlet fluid from the expander, a feed pump for returning condensed fluid from the condenser to the heater and a return path for returning the liquid phase from the separator to the heater. The liquid phase of the working fluid contains a lubricant which lubricant is soluble or miscible in the liquid phase and a bearing supply path is arranged to deliver liquid phase pressurised by the feed pump to at least one bearing for a rotary element of the expander.Type: ApplicationFiled: May 17, 2012Publication date: December 13, 2012Applicant: City UniversityInventors: Ian Kenneth Smith, Nikola Rudi Stosic, Ahmed Kovacevic
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Patent number: 8215114Abstract: A vapor power generating system for generating power by using heat from a source of heat. The system has a closed circuit for a working fluid, and includes a heat exchanger assembly (1) for heating the fluid under pressure with heat from the source, a separator (8) for separating the vapor phase of the heated fluid from the liquid phase thereof, an expander (14) for expanding the vapor to generate power, a condenser (17) for condensing the outlet fluid from the expander (14), a feed pump (F) for returning condensed fluid from the condenser (17) to the heater and a return path for returning the liquid phase from the separator to the heater. The liquid phase of the working fluid contains a lubricant which lubricant is soluble or miscible in the liquid phase and a bearing supply path (21) is arranged to deliver liquid phase pressurized by the feed pump (F) to at least one bearing for a rotary element of the expander.Type: GrantFiled: June 9, 2006Date of Patent: July 10, 2012Assignee: City UniversityInventors: Ian Kenneth Smith, Nikola Rudi Stosic, Ahmed Kovacevic
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Publication number: 20110048009Abstract: A method, and associated apparatus, for generating power from medium temperature heat sources in the range of 200° to 700° C. with improved efficiency compared to systems operating on a Rankine cycle in which the working fluid is condensed at the same temperature. Water is heated in a boiler (11) with heat from the heat source A, (22) which may be a stream of exhaust gases (22), in order to generate wet steam having a dryness fraction in the range of 0.10 to 0.90 (10% to 90% dry). The wet steam is expanded to generate power in a positive displacement steam expander (21) such as a twin screw expander. The expanded steam is condensed at a temperature in the range of 70° C. to 120° C., and the condensed steam is returned to the boiler. The expanded steam may be condensed in the boiler of an Organic Rankine Cycle (22) to provide additional power, or by heat exchange with a heater of a heating system to provide a Combined Heat and cycle, thereby further improving the cycle efficiency.Type: ApplicationFiled: February 6, 2009Publication date: March 3, 2011Inventors: Ian Kenneth Smith, Nikola Rudi Stosic
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Publication number: 20090188253Abstract: A vapour power generating system for generating power by using heat from a source of heat. The system has a closed circuit for a working fluid, and includes a heat exchanger assembly (1) for heating the fluid under pressure with heat from the source, a separator (8) for separating the vapour phase of the heated fluid from the liquid phase thereof, an expander (14) for expanding the vapour to generate power, a condenser (17) for condensing the outlet fluid from the expander (14), a feed pump (F) for returning condensed fluid from the condenser (17) to the heater and a return path for returning the liquid phase from the separator to the heater. The liquid phase of the working fluid contains a lubricant which lubricant is soluble or miscible in the liquid phase and a bearing supply path (21) is arranged to deliver liquid phase pressurised by the feed pump (F) to at least one bearing for a rotary element of the expander.Type: ApplicationFiled: June 9, 2006Publication date: July 30, 2009Applicant: CITY UNIVERSITYInventors: Ian Kenneth Smith, Nikola Rudi Stosic, Ahmed Kovacevic
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Patent number: 6296461Abstract: Helical intermeshing main and gate rotors (1, 2) are mounted for rotation about their axes in respective intersecting bores in a housing. The profiles of the rotors as seen in cross section are generated by the same rack formation. The high pressure flanks of the lobes of the main rotor (1) and of the grooves of the gate rotor (2) are both generated by a preferably cycloidal portion (GHA) of the rack R.Type: GrantFiled: November 12, 1998Date of Patent: October 2, 2001Assignee: City UniversityInventor: Nikola Rudi Stosic
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Patent number: 5833446Abstract: An apparatus is provided for deriving mechanical power from expansion of a working fluid, other than water, from a liquid state at a first pressure to vapour at a second, lower pressure, which apparatus includes positive displacement machinery, wherein the in-built volumetric expansion ratio of the positive displacement machinery is between 10 and 50% of the overall volume ratio of expansion experienced by the fluid in the pressure reduction between the entry and the exit of the machinery.Type: GrantFiled: January 15, 1997Date of Patent: November 10, 1998Assignee: Carrier CorporationInventors: Ian Kenneth Smith, Nikola Rudi Stosic