The subject matter disclosed herein relates to cleaning surfaces, including internal surfaces of gas turbines.
During operation of certain gas turbines, contaminants are often pulled into the turbine through inlets and may accumulate in internal, difficult to access places, such as rotors, compressors, lower and upper half shells and the like. Additionally, combustion byproducts of the consumed fuel may also accumulate in these places. Contaminants may negatively impact the efficiency of the turbine.
To maximize the efficiency of the turbine, it is desirable to periodically clean the internal, difficult to access places of the turbine. As cleaning necessarily results in downtime as the turbine is taken offline, it is desirable to minimize downtime by rapidly, yet thoroughly, cleaning the turbine.
Conventional cleaning techniques include hand-cleaning, dry ice cleaning and cleaning with wet steam. Hand-cleaning is the most common technique, but also the least effective. A significant amount of contaminants often remain in the difficult to access places. Dry ice cleaning is more effective than hand-cleaning but requires the use of several thousand pounds of dry ice be consumed. The logistics of keeping such a large amount of dry ice is problematic due to constant sublimation and large storage space. Wet steam cleaning is also more effective than hand-cleaning, but produces many gallons of waste water. The removal of such a large volume of waste water is a significant problem as the water is slow to evaporate.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.
A device and method for cleaning a surface using dry steam is disclosed. A dry steam wand is fitted with a custom nozzle that permits the dry steam to be angled to clean difficult to access surfaces of a gas turbine. The nozzle includes a slit that is configured to maintain sufficient temperature and pressure to effectively remove contaminants found on gas turbines. An advantage that may be realized in the practice of some disclosed embodiments of the nozzle is that gas turbine contaminants may be efficiently removed from difficult to access surfaces. Conventional nozzles were found to be ineffective for such an application.
In one embodiment, a method of cleaning a surface is disclosed. The method comprises conducting dry steam through a wand, and directing the dry steam at an acute angle relative to a longitudinal axis of the wand to clean the surface.
In another embodiment, a method of cleaning an internal surface of a gas turbine is disclosed. The method comprises conducting dry steam through a wand, directing, with a nozzle fluidly connected to the wand, the dry steam at an acute angle relative to a longitudinal axis of the wand to clean the surface, and positioning the nozzle proximate to the internal surface to maintain a temperature of greater than 350 degrees C. at the internal surface.
In yet another embodiment, a nozzle for a dry steam cleaner is disclosed. The nozzle comprises a cavity having a central longitudinal axis, and a slit in the nozzle that is spaced apart from the central longitudinal axis and accesses the cavity.
This brief description of the invention is intended only to provide a brief overview of subject matter disclosed herein according to one or more illustrative embodiments, and does not serve as a guide to interpreting the claims or to define or limit the scope of the invention, which is defined only by the appended claims. This brief description is provided to introduce an illustrative selection of concepts in a simplified form that are further described below in the detailed description. This brief description is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.
So that the manner in which the features of the invention can be understood, a detailed description of the invention may be had by reference to certain embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the drawings illustrate only certain embodiments of this invention and are therefore not to be considered limiting of its scope, for the scope of the invention encompasses other equally effective embodiments. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the features of certain embodiments of the invention. In the drawings, like numerals are used to indicate like parts throughout the various views. Thus, for further understanding of the invention, reference can be made to the following detailed description, read in connection with the drawings in which:
Disclosed in this specification is a method and device for cleaning a surface using dry steam. Dry steam is a term of art that refers to steam with a low (e.g., less than about 3%) moisture content. The method uses a specially designed nozzle to deliver dry steam to a surface for the purpose of removing contaminants deposited thereon. The nozzle permits the dry steam to be delivered at a certain pressure (e.g., greater than about 160 pounds per square inch (psi) or 1103 kPa (kilopascals)) and at a certain temperature (e.g., greater than about 350° C.). Conventional nozzles are unable to achieve these pressures and temperatures. The method and device are particularly suitable for cleaning internal surfaces of gas turbines.
In the embodiment of
The slit 312 has a depth 318 of between about 20% and 50% of a nozzle width 320 of the nozzle 300 such that the slit 312 extends into the sidewall 104. For example, the nozzle width 320 may be 0.625 inches (15.9 mm) and the depth 318 may be about 0.25 inches (6.4 mm), which is approximately 40% of the nozzle width 320. The slit has a slit width 322 that is between about 15% and about 30% of the depth 318. For example, when the depth 318 is about 0.25 inches (6.4 mm) the slit width 322 may be about 0.063 inches (1.6 mm, 25%). By way of further example, when the depth 318 is about 0.25 inches (6.4 mm) the slit width 322 may be about 0.045 inches (1.1 mm, 18%). The slit 312 has a length 326 (see
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.