Abstract:
A method of clearing residue from a fluid conduit includes commencing flush fluid flow through the fluid conduit and injecting a first fluid into the fluid conduit at a first point to induce turbulent flow of the flush fluid. The first fluid is preferably a gas. The method further includes sampling the flush fluid downstream of the first point to confirm the residue is adequately cleared from the fluid conduit.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to fluid flow systems, and more particularly to a method of flushing a fluid flow system.  
         BACKGROUND OF THE INVENTION  
         [0002]    Fluid flow systems are implemented in a variety of applications. For example, a power plant requires a water flow system, among many others, to generate steam. A particular fluid flow system can be an open-loop or closed-loop system depending upon the particular application requirements. Such fluid flow systems can transfer water, oil or any other fluid required. Often, the fluid conduits that make up the fluid flow system are made of carbon steel or some other oxidizing metal.  
           [0003]    During periods of non-use, debris suspended within the fluid settles at the bottom of the fluid conduits creating a sediment layer. Additionally, other contaminants may be present within the flow system that attach to the walls of the fluid conduits. In the case of steel conduits, oxidization can occur as a result of the fluid&#39;s oxygen content. This leads to the creation of a rust layer on the walls of the fluid conduit.  
           [0004]    When re-commissioning a dormant fluid flow system, it is necessary to flush the system of dirt, debris, crust and/or rust that has built up. Traditional flushing processes implement a flush fluid flow through the system to dislodge and flush out the dirt and debris. In some instances, mechanical devices, such as a thumper, are attached to the outside of the fluid conduits to induce vibrations in the fluid conduits. The vibrations enhance the flushing process.  
           [0005]    Traditional flushing processes are inefficient and have limited effectiveness. In many instances, the flushing process lasts an unreasonably long time and fails to adequately clear the dirt and debris from the system.  
         SUMMARY OF THE INVENTION  
         [0006]    Accordingly, the present invention provides a method of clearing residue from a fluid conduit. The method includes commencing flush fluid flow through the fluid conduit and injecting a first fluid into the fluid conduit at a first point to induce turbulent flow of the flush fluid.  
           [0007]    In one feature, the first fluid is a gas.  
           [0008]    In another feature, the method further includes sampling the flush fluid downstream of the first point to confirm the residue is adequately cleared from the fluid conduit.  
           [0009]    In still another feature, the method further includes injecting a second fluid into the fluid conduit at a second point downstream of the first point to induce turbulent flow of the flush fluid. The first fluid is the same type as the second fluid. The second point is sufficiently downstream of said first point whereby the fluid flow may be laminar upon reaching the second point. The flush fluid is sampled downstream of the second point to confirm the residue is adequately cleared from the fluid conduit.  
           [0010]    In yet another feature, the method further comprises setting the flush fluid flow to a maximum flow rate.  
           [0011]    In another feature, the method further includes inducing vibrations in the fluid conduit.  
           [0012]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0014]    [0014]FIG. 1 is a cross-sectional view illustrating a fluid conduit having a laminar fluid flow therethrough;  
         [0015]    [0015]FIG. 2 is the fluid conduit of FIG. 1 including a first injection point to inject a gas according to the present invention;  
         [0016]    [0016]FIG. 3 is a cross-sectional view illustrating an additional length of the fluid conduit of FIGS. 1 and 2 including a second injection point to inject the gas according to the present invention;  
         [0017]    [0017]FIG. 4 is a cross-sectional view of the fluid conduit of the preceding Figures including a fluid sampler inserted into the fluid conduit through the second injection point; and  
         [0018]    [0018]FIG. 5 is a schematic illustration of a closed-loop fluid circulation system including multiple flow paths and injection points according to the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0020]    Referring now to FIG. 1, a fluid conduit  10  is shown having a laminar fluid flow therethrough. An instrument  12  (e.g. pressure or temperature gauge) is positioned on the fluid conduit  10  at a first point P 1 . The instrument  12  measures a characteristic (e.g. pressure or temperature) of the fluid flow within the fluid conduit  10 . A sediment layer  14  rests at the bottom of the fluid conduit  10 . Additionally, the inside surfaces  16  of the fluid conduit  10  includes layers of rust and/or crud.  
         [0021]    Referring now to FIG. 2, the instrument  12  is removed and a fluid injector  18  is attached to the fluid conduit  10  at an orifice  20 . The orifice  20  enables fluid communication between the fluid injector  18  and the internal area of the fluid conduit  10 . It is anticipated that other orifices can be adapted as injection points including, but not limited to, vents and drains. The fluid injector  18  is attached to a compressor  22  via a hose  24 . A fluid is injected by the fluid injector  18  to induce turbulent fluid flow in the fluid conduit  10 . The injected fluid must be at a higher pressure than the fluid flowing through the fluid conduit  10 . The injected fluid is preferably a gas including air. It is appreciated that the type of gas is not limited to air and can include any type of known gas such as nitrogen.  
         [0022]    Referring now to FIG. 3, the fluid conduit  10  includes a second point P 2  located downstream of the first point P 1 . The turbulent flow induced at the first point P 1  has become laminar by the time it reaches the second point P 2 . The sediment layer  14  and the rust/crud layers have been sufficiently cleared between the first and second points. To clear these layers past the second point P 2 , the fluid is injected through the second point P 2  using the fluid injector  18  as described above.  
         [0023]    Optionally, a vibrator or thumper  26  (shown in phantom) can be attached to the outside of the fluid conduit  10  to induce vibrations through the fluid conduit  10 . The vibrations enhance the removal of the sediment layer  14  and the rust/crud layers. The thumper  26  is a mechanical device that is powered by either electric or pneumatic means, such as an electric or air motor.  
         [0024]    The fluid flow through the fluid conduit  10  is tested with fluid injection through the orifice  20  suspended. In this way, the fluid flow through the fluid conduit  10  is representative of normal fluid flow. Through testing it is determined whether the sediment and rust/crud are sufficiently removed from the fluid conduit  10 . In the particular embodiment of FIG. 4, a test probe  30  is inserted into the fluid conduit  10  through the orifice  20 . Fluid samples are taken and analyzed to determine the quality and size of any debris or other particles present in the fluid. If the fluid quality is sufficient, downstream removal of the sediment and rust/crud is commenced. For example, after a period of time removing the sediment and rust/crud from the first point P 1  on downstream, the probe  30  is inserted through the second point P 2 . A fluid sample is examined. If the fluid sample shows sufficient fluid quality, the flushing process ceases at the first point P 1  and commences at the second point P 2 , as depicted in FIG. 3. However, if the fluid quality is insufficient, the fluid process continues at the first point P 1 , as depicted in FIG. 2, until achieving the desired fluid quality. In this manner, upstream sections of the fluid conduit  10  are sufficiently flushed prior to commencing the flushing process in downstream sections.  
         [0025]    Referring now to FIG. 5, an exemplary closed-loop fluid flow system  50  is shown. Although the flushing process of the present invention is described with respect to the fluid flow system  50 , the fluid flow system  50  is merely exemplary in nature. It is appreciated that the flushing process can be implemented with any fluid flow system including open-loop fluid flow systems. The fluid flow system  50  includes a main loop  52  and three branches  54 ,  56  and  58 , respectively, made up of fluid conduits. The main loop  52  includes a pump  60 , a receiver  62  and a filter  64 . The pump  60  pumps a fluid through the fluid flow system  50 . The returning fluid is filtered through the filter  64  and flows into the receiver  62 . The receiver  62  serves as a reservoir from which fluid is drawn by the pump  60 . The receiver  62  also separates gas from the liquid fluid. The gas is bled out of the fluid flow system  50  through the receiver  62 .  
         [0026]    The main loop  52  includes injection points IP A , IP B , IP M  and IP N . The branch  54  includes injection points IP C  through IP F . The branch  56  includes injection points IP G  and IP H . The branch  58  includes injection points IP I  through IP L . The injection points are preferably points where pressure gauges, temperature gauges or other instruments are attached or a vent or drain is present. The respective gauge or instrument is removed and the injector is inserted into the open orifice. In this manner, existing orifices are used and special flushing orifices are not required.  
         [0027]    In accordance with the flushing process of the present invention, the fluid injector is initially inserted into IP A . Fluid is injected into the main loop  52  through IP A  to induce turbulent fluid flow therein. As described above, a thumper can also be implemented to induce vibrations in the fluid conduit in the vicinity of IP A . The probe is inserted in IP B  and fluid samples are taken. Prior to taking the fluid samples, the fluid injection is ceased. In this manner, the fluid samples are indicative of normal system operation. If the fluid samples are not of a sufficient quality, the flushing process remains at IP A . If the quality is sufficient, the fluid injector is removed from IP A  and the gauge or instrument is reattached to IP A . The flushing process then continues at IP B . The flushing process at the injection points is carried out using various injection and system fluid flow rates. These flow rates are varied during the flushing process to determine the most effective combination of injection and system fluid flow rates.  
         [0028]    The flushing process at IP B  commences similarly as described with regard to IP A . Fluid is injected into the main loop  52  through IP B  to induce turbulent fluid flow therein and a thumper is optionally implemeted. The main loop  52  splits to form the three branches  54 ,  56 ,  58  downstream of IP B . The fluid samples are taken around the split  66 . If the fluid samples are not of a sufficient quality, the flushing process remains at IP B . If the quality is sufficient, the fluid injector is removed from IP B  and the gauge or instrument is reattached to IP B . The flushing process then continues in the branches.  
         [0029]    Preferably, one branch is flushed prior to flushing the next branch. The flushing process commences in the first branch  54  at IP C  of the first branch  54 . Fluid is injected into the first branch  54  through IP C  to induce turbulent fluid flow therein and a thumper is optionally implemeted. Fluid samples are taken at IP D  of the first branch  54 . If the fluid samples are not of a sufficient quality, the flushing process remains at IP C . If the quality is sufficient, the fluid injector is removed from IP C  and the gauge or instrument is reattached. The flushing process then continues through the remaining injection points of the first branch  54  until the first branch  54  is sufficiently cleared.  
         [0030]    The same process is repeated for the second and third branches  56 ,  58  as described for the first branch  54 . The branches rejoin the main loop at a convergence point  68 . Once the branches  54 ,  56 ,  58  are sufficiently flushed, flushing of the main loop  52  continues at IP M . The flushing process at IP M  commences similarly as described above with the fluid samples taken at IP N . The flushing process then commences at IP N  with fluid samples taken at the filter  64 .  
         [0031]    The filter  64  filters the sediment and rust/crud that is dislodged by the flushing process. The filter  64  is periodically cleaned or replaced to ensure sufficient fluid flow therethrough. As a result of the gas injection at the various injection points, an undesirable gas build-up could occur. However, the receiver  62  separates the injected gas from the fluid flowing from the system  50 . The gas is bled from the system  50  by the receiver  62 .  
         [0032]    The specific type of gas used depends on several factors including the type of fluid system and cost. For example, air compressors or an air supply system may already be present at the location. If the air pressure of an existing system is insufficient, pressure boosters or high-pressure compressors can be temporarily implemented. Although air may be less expensive, the oxygen content of the system fluid may be increased by using air. Thus, a gas, such as nitrogen, could be implemented to eliminate any corrosive effects of increased oxygen content. Additionally, an alternative to air would be desired in the case of a fluid such as oil flowing through the system.  
         [0033]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.