Valve with integrated actuating device, especially for a combustion system

Abstract

A valve, in particular for combustion systems, comprising: a valve body (12), at least one inlet line (14) and at least one outlet line (18) for this fluid, arranged on the valve body, a closing element (22) configured to provide fluid communication between these lines, an actuating device (26) of the closing element (22) configured to be electrically controlled, an inner housing (20) arranged within the valve body (12) in which the closing element (22) and the actuating device (26) are accommodated, a cooling circuit (28) formed within the valve body between the inner housing (20) and the valve body (12) and forming a circumferential circuit that completely surrounds the inner housing (20), the closing element (22) and the actuating device (26), and at least one inlet line (38) and at least one outlet line (40) for this fluid.which are arranged on the valve body (12) and are in fluid communication with the cooling circuit.

Description

The present invention relates generally to the field of valves and, more particularly, to valves used in fuel delivery systems of combustion systems such as gas turbines, boilers, burners, etc.Industrial combustion systems combust a mixture of an oxidizing agent such as oxygen and fuel such as gas or liquid fuel. In the case of multi-fuel systems, these generally do not use liquid fuels and gaseous fuels simultaneously, but are alternately supplied with both fuels. The operation involved in changing the fuel supply is usually described by the term "changeover". Following such fuel switching, the delivery system of one of the fuels is stopped.During the stopping of the liquid fuel, the still liquid may be subjected to solidification in the presence of air due to high temperatures.In the case where the fuel is liquid fuel, this phenomenon is described by the term "coking.".Such solidification is characterized in particular by a disturbance of sensitive elements of the combustion system, the sealing function of mechanical components such as valves and check valves and by the reduction of the fuel flow rate in the combustion system.In order to overcome these disadvantages in the case of a gas turbine, it is known to discharge the residual liquid fuel in the combustion system, for example, by a first flushing step through the inlet of pressurized water followed by a second flushing step in which pressurized gas is introduced to discharge the water.Valves are provided in the supply system to allow distribution of the liquid fuel, the purge air and the purge liquid. Typically, such valves each have a plurality of inlet conduits mounted on the valve body for the supply of fuel liquid, purging liquid and purging gas and a closure member movably disposed within the body to ensure fluid communication between the various conduits. Each valve is generally associated with a pneumatic actuator for controlling the closure element. The pneumatic actuator is disposed adjacent the associated valve and includes a control spindle extending across the interior of the valve body for being mechanically connected to the closure member.Such a pneumatic actuator is used to the extent that this type of actuator is capable of withstanding high temperatures, unlike an electric actuator whose maximum operating temperature generally does not exceed 85°C. In fact, the associated valve is generally placed in the vicinity of the combustion chamber(s) of the turbine, in zones in which temperatures as high as 190°C can be reached.This solution, however, has a major disadvantage in that it requires the use of several compressed air supply lines for each pneumatic actuator associated with a valve.As a result, a large number of air supply lines are provided for the entire turbine supply system having a plurality of valves. Moreover, this solution requires the use of an air compression system.EP 1 223 317 A2 describes a fluid control valve having a valve body, a fluid inlet, a fluid outlet and a closing element. The closing element is moved via an actuating device. The valve is cooled via a cooling circuit. A similar valve is known from US 5 706 851 A.The present invention aims to remedy these disadvantages.The invention relates to a valve, in particular for a combustion system, comprising a valve body, at least one first fluid inlet line and at least one outlet line for this fluid, which are arranged on the valve body, a closing element, which is arranged movably in the valve body and is capable of ensuring fluid communication between these lines, and an actuating device for this closing element, which is arranged in the valve body and is capable of being electrically controlled. The valve also includes a cooling circuit disposed in the valve body surrounding the actuator and at least one cooling fluid inlet conduit and at least one outlet conduit for that fluid disposed on the valve body and in fluid communication with the cooling circuit.Thus, a valve with an actuator which is completely integrated into the valve body is obtained. This simplifies the positioning of the valve on the associated supply system and the structure of this system. Moreover, the cooling circuit enables cooling of the electrically controlled actuator, which enables the valve to be used in high temperature areas, for example in the vicinity of the combustion chamber(s) of a combustion system. In addition, the command response time is reduced.In one embodiment, the actuating means comprise a mechanical element connected to the closure element and an electrical control means for said element. The cooling circuit preferably encloses at least a part of the electrical control means. A partition wall may be arranged between the closing element and the electrical control means.The cooling circuit completely surrounds the closing element and the actuating device.The valve has an inner housing which is arranged in the valve body and in which the closing element and the actuating device are accommodated. The cooling circuit is formed between the inner housing and the valve body.In the embodiment, the valve has first, second and third inlet lines which are arranged on the valve body and are designed to be supplied with fuel liquid or flushing liquid or flushing gas.The closure element may comprise a single circulation channel arranged on the closure element to enable fluid communication between each of the inlet lines and the outlet line in three different positions of the closure element.The invention also relates to a supply system for a fuel system comprising at least one combustion chamber which can be supplied with fuel liquid, wherein the supply system comprises inlet means for fuel liquid, inlet means for flushing liquid, inlet means for flushing gas and a valve as defined above, wherein the first, second and third inlet lines of the valve are connected to the inlet means of fuel liquid, the inlet means of flushing liquid and the inlet means of flushing gas.The present invention will be better understood after reading the detailed description of an embodiment used as an example, which is by no means complete and is illustrated by the accompanying drawing, which schematically shows a valve based on an example of the invention.The drawing illustrates an embodiment of a valve, generally designated 10, configured to be used in a fuel system delivery system having one or more combustors capable of being supplied with gas or liquid fuel. The combustion system may be, for example, a turbine, a boiler, a burner, etc.The valve 10 comprises an outer valve body 12, an inlet conduit 14 adapted to be supplied with liquid fuel, a first purging conduit 16 adapted to be supplied with purging gas, a second purging conduit (not shown) perpendicular to these conduits and adapted to be supplied with purging liquid, an outlet conduit adapted to be connected to the combustion chamber or chambers of the associated combustion system, respectively, an inner housing 20 arranged in the outer valve body 12 and a spherical closure element 22 arranged movably with respect to the housing within a housing 24 of complementary shape. The second purge line is disposed in a plane different from the plane including the inlet line 14, the purge line 16, and the outlet line 18.The inlet pipe 14 and the two scavenging pipes and the outlet pipe 18 are separate and arranged on the valve body 12 so as to extend into the inside thereof and open into the housing 24 of the inner housing. In the illustrated embodiment, the outer valve body 12 and the inner housing 20 have a generally rectangular shape. As a variant, other shapes, for example square or spherical shapes, may be used. The inner housing 20 and the closing element 22 are advantageously made of metal, which assists a good seal between these two elements.The valve 10 also includes a closure element actuator 26 disposed fully within the valve body 12 and an associated cooling circuit 28 for allowing the valve to be disposed in high temperature areas in the vicinity of the combustion chamber(s) of the system.The actuator 26 is disposed within the inner housing 20 and includes a control spindle 30 and an electrical spindle control means 32. The control spindle 30 is mechanically connected at one of its ends to the closing element 22 to allow the latter to rotate with respect to the valve body 12 and the inner housing 20. The control spindle 30 extends over a partition wall 34 disposed in the inner housing 20. Taking into account the axis of extension of the control spindle 30, the partition wall 34 is arranged axially between the closing element 22 and the electrical control means 32. The partition 34 provides sealing between these two elements.The electrical control means 32 allows the control spindle 30 to be rotationally driven about its axis of extension. The electrical control means 32 may be, for example, a brushless or direct current motor mechanically connected to the control spindle 30. Alternatively, the electrical control means 32 may be an electric motor magnetically connected to the control spindle 30. The valve 10 also includes electrical connection means (not shown) capable of electrically connecting the control means 32 to a source of electrical energy external to the valve. Under the actuation of the electrical actuator 26 receiving electrical energy, the closure member 22 is rotatably movable within the housing 24 of the inner housing to selectively connect the outlet conduit 18 of the valve to the liquid fuel inlet conduit 14 or to the gas purge conduit 16 or the liquid purge conduit. The closing element 22 is rotatably movable about an axis 22a coaxial with the axis of the control spindle 30. In the embodiment shown, the closure member 22 includes a single circulation channel 36 for establishing fluid communication between the liquid fuel inlet line 14 and the outlet line 18 in a first position with respect to the inner housing 20 and the body 12, as shown in the drawing. In this position, the valve 10 allows the combustion chamber or chambers of the combustion system to be supplied with liquid fuel. Here, the circulation channel 36 is generally L-shaped and may be machined on the closure member 22.In a second position of the closure element 22, the circulation channel 36 ensures the connection of the liquid play line to the outlet line 18. In this position, the valve 10 allows the flushing liquid to enter the supply system of the combustion system to discharge the remaining liquid fuel in this system. In a third position of the closure element 22, the circulation channel 36 ensures fluid communication between the flushing line 16 and the outlet line 18. In this third position of the closure element 22, the valve 10 allows the flushing gas to pass into the liquid fuel supply system of the combustion system in order to allow the remaining flushing liquid introduced previously to be discharged.In the illustrated embodiment, the cooling circuit 28 is arranged on the inside of the valve body 12 to ensure cooling of both the closure element 22 and the actuator 26. The cooling circuit 28 is formed between the outer body 12 and the inner housing 20. The cooling circuit 28 forms a circumferential circuit which completely surrounds the inner housing 20, the closing element 22 and the actuating device 26. The cooling circuit 28 extends over the entire length of the closing element 22 and of the actuating device 26.In order to ensure the circulation of cooling fluid within the circuit 28, the valve 10 also comprises an inlet line 38 and an outlet line 40. The conduits 38, 40 are disposed at opposite ends of the valve body 12. The cooling fluid may be, for example, water or another suitable fluid.The cooling circuit 28 allows the inlet conduit 14 and the closure element 22 to be cooled in a manner such that the risk of the liquid fuel within these two elements solidifying is limited. In addition, the cooling circuit 28 ensures cooling of the electric actuator 26 that allows the valve 10 to be mounted in high temperature areas in the vicinity of the combustion chamber(s) of the combustion system. For this purpose, the valve 10 also has a fastening flange 42 through which the outlet line 18 extends.In the embodiment shown, the closure element has a single circulation channel to ensure the communication between the outlet duct and the various inlet ducts for fuel liquid and scavenging fluid. As a variant, it is possible to provide two separate circulation channels, one for the circulation of fuel liquid and purging liquid and the other for the circulation of purging gas. In addition, in the exemplary embodiment shown, the closing element has a generally spherical shape and is rotatably mounted in a movable manner. As a variant, the closing element can also have the form of a rotatably movable cylinder or cone or a translationally movable cylinder or slide.In the embodiment described, the cooling circuit is formed between the inner surface of the outer body 5 of the valve and the inner surface of the inner housing in which the closing element and the associated actuator are housed. As a variant, it may be possible not to provide an inner housing and to arrange the closing element and the actuating device directly in the interior of the valve body. In this case, the cooling circuit may be formed in the thickness of the valve body.In the illustrated embodiment, the valve is intended to be used in the liquid fuel supply system of the combustion system. As a variant, it may also be possible to use the valve in the gas fuel supply system of the combustion system or even in another type of application which has to be installed in a high temperature zone and requires the use of one or more different types of fluids.The valve, in particular for a combustion system, comprises a valve body 12, at least one first inlet line 14 and at least one outlet line 18 for this fluid, which are arranged on the valve body, a closing element 22 which is arranged movably inside the valve body and is configured to establish a fluid connection between the lines, and an actuating device 26 for the closing element, which is arranged inside the valve body 12 and is configured to be electrically controlled. The valve also includes a cooling circuit 28 disposed within the valve body and enclosing at least a portion of the actuator 26 and at least one cooling fluid inlet conduit 38 and at least one outlet conduit 40 for that fluid disposed on the valve body 12 and in fluid communication with the cooling circuit.

Claims

Valve, in particular for combustion systems, comprising: a valve body (12), at least one inlet line (14) and at least one outlet line (18) for this fluid, which are arranged on the valve body, a closing element (22), which is arranged to provide fluid communication between these lines, an actuating device (26) of the closing element (22), which is arranged to be electrically controlled, an inner housing (20), which is arranged inside the valve body (12) and in which the closing element (22) and the actuating device (26) are accommodated, a cooling circuit (28), which is formed inside the valve body between the inner housing (20) and the valve body (12) and forms a circumferential circuit, which completely surrounds the inner housing (20), the closing element (22) and the actuating device (26), and at least one inlet line (38) and at least one outlet line (40) for this fluid, which are arranged on the valve body (12) and are in fluid communication with the cooling circuit.Valve according to claim 1, wherein the actuating device (26) comprises a mechanical element connected to the closure element and an electrical control means (32) for said element.A valve according to claim 2, wherein the cooling circuit (28) surrounds at least a part of the electrical control means (32).Valve according to claim 2 or 3, comprising a partition (34) arranged between the closure element (22) and the electrical control means (32).Valve according to any one of the preceding claims, wherein the cooling circuit (28) completely surrounds the closure element (22) and the actuator (26).Valve according to any of the preceding claims, comprising an inlet line (14) adapted to be supplied with fuel fluid, a first flushing line (16) adapted to be supplied with flushing gas and a second flushing line adapted to be supplied with flushing liquid, wherein the inlet line (14), the first flushing line (16) and the second flushing line are arranged on the valve body (12).A valve according to claim 6, wherein the closure element (22) comprises a single circulation channel (36) arranged on the closure element for establishing fluid communication between each of the inlet lines and the outlet line in three different positions of the closure element.A supply system for a combustion system comprising at least one combustion chamber operable with fuel fluid, said supply system comprising a fuel fluid inlet means, a flushing liquid inlet means, a flushing gas inlet means and a valve according to any of claims 6 or 7, wherein a first, second and third inlet line of said valve is connected respectively to said fuel fluid inlet means and said flushing liquid inlet means and said flushing gas inlet means.

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