Cooling system for control valve actuators

The present application provides a control valve actuator cooling system for providing a flow of cooling air to a control valve actuator. The control valve actuator cooling system may include a pressurized air source with the flow of cooling air, an air timing valve system, and a cooling air discharge port positioned about the control valve actuator such that the air timing valve system provides the flow of cooling air to the control valve actuator on an intermittent basis.

TECHNICAL FIELD

The present application and the resultant patent relate generally to gas turbine engines and more particularly relate to an auxiliary air cooling system for cooling control valve actuators via air timing valves and the like instead of complex electrical components.

BACKGROUND OF THE INVENTION

In gas turbine engines, a portion of the total airflow from the compressor may be diverted to cool various turbine components. Specifically, a flow of bleed air may be extracted from a stage of the compressor to cool a stage of the turbine or other components. This diverted airflow, however, may consume a significant portion of the total airflow through the compressor. The management and control of these parasitic airflows thus may increase the overall efficiency and performance of the gas turbine engine.

The airflow extractions from the compressor may be controlled by one or more control valves positioned on the extraction lines. Although the actuators for these control valves generally may be mounted externally to the gas turbine enclosure so as to protect the actuators from the high temperatures within the enclosure, there are some control valves installed within the enclosure. The internal air surrounding these control valves may reach high temperatures and may be somewhat stagnant. In such situations, the heat reaching the control valves may not be dissipated such that the actuators may fail due to the high temperatures. As a result, known actuator cooling system may use complex mechanical or electronic devices so as to provide cooling. These cooling systems thus may be a parasitic drain on the overall gas turbine engine.

There is thus a desire for an improved control valve actuator cooling system. Preferably such an improved system may provide cooling to the control valve actuators without the use of complex components so as to provide increased reliability and decreased costs.

SUMMARY OF THE INVENTION

The present application and the resultant patent thus provide a control valve actuator cooling system for providing a flow of cooling air to a control valve actuator. The control valve actuator cooling system may include a pressurized air source with the flow of cooling air, an air timing valve system, and a cooling air discharge port positioned about the control valve actuator such that the air timing valve system provides the flow of cooling air to the control valve actuator on an intermittent basis. The intermittent basis may vary.

The present application and the resultant patent further provide a method of cooling an actuator used with a control valve in a gas turbine engine. The method may include the steps of providing a source of pressurized air, flowing the pressurized air to an air timing valve system, building pressure within the air timing valve system, opening the air timing valve system at a predetermined pressure, and flowing the pressurized air to the actuator for a predetermined length of time to cool the actuator. The predetermined length of time may vary.

The present application and the resultant patent further provide a gas turbine engine. The gas turbine engine may include a compressor, a turbine, and an air extraction system extending from the compressor to the turbine. The air extraction system may include one or more control valve actuators positioned about the turbine and a control valve actuator cooling system for providing an intermittent flow of cooling air to the control valve actuators.

DETAILED DESCRIPTION

Referring now to the drawings, in which like numerals refer to like elements throughout the several views,FIG. 1shows a schematic view of gas turbine engine10as may be used herein. The gas turbine engine10may include a compressor15. The compressor15compresses an incoming flow of air20. The compressor15delivers the compressed flow of air20to a combustor25. The combustor25mixes the compressed flow of air20with a pressurized flow of fuel30and ignites the mixture to create a flow of combustion gases35. Although only a single combustor25is shown, the gas turbine engine10may include any number of combustors25. The flow of combustion gases35is in turn delivered to a turbine40. The flow of combustion gases35drives the turbine40so as to produce mechanical work. The mechanical work produced in the turbine40drives the compressor15via a shaft45and an external load50such as an electrical generator and the like.

The gas turbine engine10may use natural gas, liquid fuels, various types of syngas, and/or other types of fuels and blends thereof. The gas turbine engine10may be any one of a number of different gas turbine engines offered by General Electric Company of Schenectady, N.Y., including, but not limited to, those such as a 7 or a 9 series heavy duty gas turbine engine and the like. The gas turbine engine10may have different configurations and may use other types of components. Other types of gas turbine engines also may be used herein. Multiple gas turbine engines, other types of turbines, and other types of power generation equipment also may be used herein together.

The gas turbine engine10also may include an air extraction system55. As described above, one or more extractions of high pressure air may be taken from the compressor15and delivered to the turbine40or elsewhere for cooling purposes. The air extraction system55may include a number of air extractions lines60. Although only one air extraction line60is shown, the air extraction system55may have any number of air extraction lines as well as related bypass lines, ejectors, and other components. The air extraction line60may have one or more control valves65positioned thereon. Each control valve65may be operated by an actuator70. The actuator70may be a solenoid and the like for largely on/off operation. Other types of actuators may be known. Although the actuator70may be mounted externally to the turbine enclosure, the actuator70may be in a high temperature environment. The air extraction system55described herein is for the purpose of example only. Many other types of air extraction systems and components thereof may be known.

FIGS. 2 and 3show an example of a control valve actuator cooling system100as may be described herein. The control valve actuator cooling system100may be used with a control valve110of the air extraction system55or other systems of the gas turbine engine10. Any number of the control valves110may be used herein. Similar to those described above, the control valve110may be operated by an actuator120. The actuator120may include a solenoid and the like for largely on/off operation. Other types of actuators and other types of control devices may be used herein. Any number of the actuators120or other types of devices may be used and cooled herein.

The control valve actuator cooling system100may include a pressurized air source130for providing the flow of cooling air115. The pressurized air source130may be any source of pressurized air including, for example, instrumentation air and the like. Other types of pressurized air sources130may be used. The pressurized air source130may be in communication with the actuator120via a cooling air line140. Depending upon the pressure of the pressurized air source130, the control valve actuator cooling system100may include a pressure regulator150on the cooling air line140. The pressure regulator150may be of conventional design. An upstream pressure gauge160and a downstream pressure gauge170may be positioned about the pressure regulator150. The pressure regulator150and the pressure gauges160,170may ensure that the air flowing therethrough is within a predetermined pressure range. The pressure gauges160,170may be of conventional design. In this example, the pressurized air source130may be at about 70 bar or so. The pressure regulator150may reduce the pressure to about 0.7 bar or so. Other pressures may be used herein. One or more filters175may be positioned on the cooling air line140. Other components and other configurations may be used herein.

The control valve actuator cooling system100also may include an air timing valve system180positioned upstream of the actuator120. The air timing valve system180may have an input port190and an output port200positioned on the cooling air line140. The air timing valve system180may include an adjustable timing valve210positioned between the input port190and the output port200. The adjustable timing valve210may be fed from a timing valve line220upstream thereof. The adjustable timing valve210may have an internal diaphragm225and the like. The size of the internal diaphragm225and other components within the adjustable timing valve210may vary so as to accommodate different pressures and timing therein. The adjustable timing valve210may be of conventional design.

Suitable air timing valve systems180may be offered by Festo Corporation of Hauppauge, N.Y. under the designation “PZVT” and the like. Moreover, suitable air timing valve systems180also may be offered by SMC Corporation of America of Yorba Linda, Calif. under the designation “MVR Air timer” and “KLC Air Timer”. Other types of suitable air timing valve systems may be used herein. An upstream isolation valve230and a downstream isolation valve240may surround the adjustable timing valve210. The isolation valves230,240may be of conventional design.

The control valve actuator cooling system100also may include one or more cooling air discharge ports250positioned about the cooling air line140. The cooling air discharge port250may be positioned about the actuator120so as to provide the flow of cooling air115thereto. Depending upon the configuration of the actuator120, the cooling air discharge port250may be positioned within a heat shield or a similar type of structure. The cooling air discharge port250may have any size, shape, or configuration. Other components and other configurations also may be used herein. More than one cooling air discharge port250may be fed from the control valve actuator cooling system100. Different control valve actuator cooling systems100may have different cooling sequences and the different cooling sequences may be varied.

In use, the control valve actuator cooling system100provides a flow of the cooling air115to the actuators120on an intermittent basis. Specifically, the adjustable timing valve210of the air timing valve system180may be kept in the off or closed position. The flow of cooling air from the pressurized air source130may flow through the pressure regulator150and the cooling air line140. A portion of the flow of cooling air115may be diverted via the timing valve line220into the adjustable timing valve210. When the pressure and/or volume within the adjustable timing valve210reaches a predetermined value, the adjustable timing valve210opens such that the flow of cooling air115may pass through the inlet port190and the output port200of the air timing valve system180to the cooling air discharge ports250positioned about the actuator120. The cooling air115thus cools the actuator120for a predetermined amount of time until the pressure within the adjustable timing valve210again drops so as to close the air timing valve system180. (Although the adjustable timing valve210has been described in terms of being normally closed, other embodiments may use the adjustable timing valve210that may be normally in an open position.)

The control valve actuator cooling system100thus provides a flow of cooling air to the actuators120without the use of complex electrical or electro-mechanical components. Rather, the air timing valve system180uses the flow of cooling air115as both the cooling fluid and the power source. The timing of the intermittent cooling sequence may be varied. The control valve actuator cooling system100thus may reduce the temperature rating of the valve and the associated equipment therewith. Moreover, the control valve actuator cooling system100may reduce the capital investment with respect to the cost of the product while increasing overall system reliability.