the arrangement in fig1 illustrates the features of practicing the method of the invention . fluid is passing through the pipeline 10 . a pig device 12 , which is generally a short cylindrical body , is shown passing through the pipeline . generally , the outer diameter of the pig is sized to fig snuggly inside the pipeline . the pig 12 is carried by the fluid pressure through the pipeline 10 to remove dirt , debris and corrosion , and ultimately ends its travel through the pipeline 10 at pig receiver 14 . the pig receiver 14 is generally a cylindrical body at the end of the pipeline 10 that terminates with a pig receiver opener 16 that can be swung open to remove the pig once it completes its travel through the pipeline . the normal vent valves are shown but not numbered on the pipeline and pig receiver 14 . there is a bypass line 18 that connects the pig receiver 14 to the pig launcher body 20 . the pig launcher body 20 is shown with the standard vent valves that are not numbered . the pig launcher body 20 is cylindrical and has the pig launcher opener 22 at one end . the other end of the pig launcher body is attached to the pipeline 24 , which resumes carrying the fluid downstream to the destination . in fig1 , the pig launcher body is shown cut away with a filter cartridge carrier assembly generally indicated at 26 . the filter assembly 26 is composed of three filters 28 a , 28 b and 28 c that are arranged in a linear fashion inside the pig launcher body 20 . filter 28 a is the terminal filter next to the pig launcher opener 22 and has a cap 30 on the terminal end of the outlet of the filter . the cap 30 may be replaced with a rupture plate that will break when the differential pressure exceeds a predetermined level . the filters shown in fig1 are outside / in filters with filter media surrounding a central core that is fluid permeable . the central core is connected to an inlet and outlet of the filter that is not fluid permeable . filter 28 a is held in place in the pig launcher body in part by filter centralizer body 32 a . the filter centralizer body has legs extending from a generally circular disc such that the legs are sized to hold the filter in the pig launcher body during the filtering process . the legs do not have to have a close tolerance to the inside of the pig launcher body , but provide support and stability for the filters . the filter centralizers also have a central opening sized to receive the filter inlet or outlet as shown in more detail in fig3 . the filter centralizers also have openings to receive tie rods on their outer perimeter for connecting the multiple filter centralizers . filter 28 b is connected to filter 28 a with filter centralizer 32 b . tie rods connecting filter stabilizer 32 a to 32 b in fig1 are shown at 34 a and 34 b . similarly , tie rods 34 c , 34 d , 34 e and 34 f connect the filter centralizers 32 b , 32 c and 32 d in the same manner . the outlet of filter 28 a is received into the central opening of filter centralizer 32 b , while the inlet to filter 28 b is received on the other end of the opening , thereby providing fluid communication between the filters . filter 28 b outlet and filter 28 c inlet are similarly connected with filter centralizer 32 c in a pressure tight manner . fig1 shows three filters in the filter cartridge assembly 26 . however , as shown elsewhere , as many filters as necessary can be used , and the arrangement in fig1 is for illustrative purposes . the outlet of filter 28 c is inserted into the central opening of filter centralizer 32 d . the opposite end of the opening of 32 d is connected to a tube conduit 36 , which extends from the outlet of the filters and carries the filtered fluid . the tube conduit 36 also has centralizers 38 a and 38 b to support it inside the extension of the pig launcher , which as shown in fig1 may have a smaller diameter than the pig launcher body . the centralizers are sized to hold the conduit tube in place . the terminal end of the conduit tube going downstream is tapered and fitted with o - rings to slide into sump plate 40 as shown in fig1 . sump plate 40 is held between flanges 41 a and 41 b and is the only modification to the pipeline that needs to be made to practice the method of this invention . sump plate 40 has a smaller diameter than the flange and pipeline opening . the tube conduit 36 is adapted to fit tightly in the sump plate because it has a tapered end 42 that can be guided into the sump plate 40 . there is a collar 44 at the end of the taper to stop the travel of the conduit tube 36 into the sump plate 40 . the sump plate 40 is fitted with o - rings shown at 46 a and 46 b . the sump plate arrangement is a convenient way to secure the flow of the filtered fluid to the downstream pipeline 48 . however , other means known to those skilled in the art can be used to practice the method of this invention . fig2 is an embodiment of the invention with additional filters of smaller relative diameters shown . for ease of reference , the same numerals will be used for the corresponding parts , and new numerals will be used for the additional filters . there arc three additional filters shown as 50 a , 50 b and 50 c that are shorter and smaller in diameter relative to filters 28 a , 28 b and 28 c , illustrating the feature of the method that any size or number of filters may be used . the additional filters are connected in a linear manner in the pig launcher body 20 and the extension of that body that has a smaller diameter by using filter centralizers 54 a , 54 b and 54 c of the same construction as previously described for fig1 . similarly , the tie rods 52 a , 52 b , 52 c , 52 d , 52 e and 52 f connect the central stabilizers . filter 50 c is the terminal downstream filter in fig2 . the outlet of filter 50 c is connected through the central opening of the stabilizer . fig3 is a detailed depiction of a portion of an embodiment of the filter cartridge carrier assembly 26 as shown in fig1 and 2 . the filter centralizers are shown in greater detail with the leg extensions numbered 102 a and 102 b on filter centralizer 100 a . the legs terminate in a flat , slightly rounded foot that can contact the inside of the pig launcher or receiver body holding the filter cartridge carrier assembly so that it is held safely within the body during fluid flow . the filter centralizers have tubular members extending through the central opening on either side of the filter centralizer . as the centralizers are fastened to the filters , they perform the dual purpose of maintaining the filter cartridge carrier assembly in the pig launcher or receiver body and attaching the filters to allow flow of pressurized fluid through the central cores of the attached filters in the assembly . the filter centralizer tubes fit tightly on the filter inlets and outlets which are shown , and are provided with o - rings as shown on filter 108 in fig3 . any other means of providing a pressure tight fit may be used . in fig3 , the filter 108 has an inlet tube that is shown with the o - ring neck that fits inside the filter centralizer tube 104 a . the filters are joined with the filter centralizers between each filter as shown in detail in fig3 . the filter centralizer bodies can also be provided with openings on their perimeter to receive tie rods to stabilize the filter cartridge assembly . as shown in fig3 , filter centralizer 100 a has three pair of openings to receive tie rods that connect each adjacent filter stabilizer . tie rods 110 a , 110 b and 110 c connect filter centralizers 100 a and 100 b with three tie rods surrounding the outside of filter 108 . the tie rods shown are threaded and extend the length of the filter 108 and through the filter centralizers 100 a and 100 b . the tie rods are fastened by a nut to secure the end of the tie rod that extends through the body of each of the filter centralizers 100 a and 100 b . the tie rods are not essential to the invention . any method or apparatus to stabilize the filters can be used and are known to those skilled in the art . to further illustrate the invention , fig4 is a detailed drawing of a filter cartridge carrier assembly that holds more than one filter in parallel . the figure shows three filters in parallel that are connected with filter centralizers in a similar fashion to fig3 . the parallel filter centralizer 120 has three openings , rather than one central opening , through which tubes extend on either side to connect with filter inlets and outlets . the parallel filter cartridge assembly can be used when the configuration of the pig launcher or receiver is sized to accompany this arrangement or when the need requires optimizing the number of fibers used . the parallel filter stabilizer body 120 is shown with the tubes 122 a , 122 b and 122 c extending from the body of the stabilizer . these tubes fit tightly around the inlets and outlets of the inflow filters 124 a , 124 b and 124 c , which are in parallel flow . then the tubes connect to outflow filters 124 a , 124 b and 124 c , respectively . the tie rod stabilizer arrangement is also shown in fig4 and functions in the same manner as previously described . at the terminal end of the filter cartridge for the parallel filter arrangement , a specialized filter centralizer 130 may be used as shown in fig5 . the centralizer has three tubes 132 a , 132 b and 132 c extending from one end of the centralizer that feed the filtered fluid from the terminal filters into a conical body 134 extending from the centralizer that collects the filtered fluid from the terminal three filters in the parallel arrangement as shown in fig4 . the conical body 134 tapers to a round neck 136 that extends from the conical body and is fitted with grooves for o - rings so that it can connect with tube conduit and the fluid can resume travel through the pipeline . the arrangement shown in fig1 and 2 with the tapered conduit tube 36 with the tapered end 42 can be used . however , any type of pressure tight connectors may be used . fig6 a , 6 b and 6 d illustrate the ease in preparing the filter assembly cartridge and loading into a pig launcher . for ease of reference , the same numerals from fig1 and 2 are used . the filter flow to the pig launcher is halted , and the pig launcher opener 22 is swung to the open position to allow for entry of the filter cartridge assembly . the tube conduit with tapered end 42 , with the collar securing the o - rings 46 a and 46 b , enter the pig launcher receiver body 14 first . the same arrangement of tube conduit centralizers 38 a and 38 b are used . the number of filters used to practice the invention depends on the desired filtration and the size of the pig launcher . if the pig launcher is not the desired length and needs to be longer to accommodate more filters , a cylindrical extension may be connected to the opening end of the pig launcher . these parts are known as “ spools ” and are connected to the end of the pig launcher with flange and gasket connections . any type of filter may be used depending on the fluid being transported and the impurities that need removal . the filters are typically cylindrical in shape . the filters illustrated in the figures are platinum ™ series filters made by filtration technologies corporation , and are fully described in u . s . pat . no . 5 , 824 , 232 , which patent is fully incorporated by reference herein . filter 28 c is stabbed into the tube in filter centralizer 32 d in a pressure tight connection to provide communication of the filtered fluid from the core of filter 38 c to the conduit tube 36 . the centralizers are used to guide the filters in and out of the pig launcher body and / or the pipe holding the filters . the centralizers are sized to fit comfortably inside the pipe and support the filters . as shown in fig6 b , the filters are added to the assembly by use of a filter centralizer 32 c to connect the filter 28 b so that the cores of the filters communicate in a pressure tight connection . the tube conduit 36 travels through the pig launcher body . the number of filters and the length of the conduit tube are sized so that the tapered end 42 of conduit 36 will extend and seal into the sump plate as shown in fig1 and 2 . fig6 c shows the connection of the three filters 28 a , 28 b and 28 c and their introduction into the pig launcher 14 . in fig6 d the pig launcher opener 22 is swung to the closed position , and fluid can be introduced for filtration . the fluid enters from bypass line 18 as shown in fig1 and 2 into the pig launcher with the filter assembly secured inside . the fluid enters from the outside of the filters under pressure and through the selected filter media . the fluid then passes into the cores of each of the filters 28 a , 28 b and 28 c . the filters are connected in the manner described so that the cores communicate the filtered fluid and passes it through the cores to the tube conduit 36 . the filter fluid then resumes flow through the pipeline . typically , one modification of the pipeline is required to accommodate the invention . the tube conduit &# 39 ; s tapered end 42 is secured in a sump plate 40 as shown in fig1 and 2 . the sump plate 40 is placed at a flanged connection typically already present in the pipeline . fig7 and 8 show a detail of sump plate 40 that is inserted between flanges 41 a and 41 b and secured as shown in fig8 . the connection is pressure tight , and gaskets ( not shown ) of other means to provide a pressure tight connection can be made as commonly known to those skilled in the art . fig9 is a schematic drawing of an underground pipeline with a pig launcher 200 and a pig receiver 202 . the pipeline 204 is underground between the pig launcher and receiver . the various bypass lines are not shown . this drawing illustrates the case of using the method of the present invention to filter fluid in the pipeline without hauling a separate high pressure filtration to a site and having the installation difficulties using a separate filtration unit . the drawing also shows a pig launcher receiver 202 that can be used to house a filter cartridge carrier assembly and practice another variation of the method of this invention . the filtration method can be employed using the pig receiver to hold the filter cartridge assembly . this is especially useful at the end of the pipeline where there is no pig launcher . the filters are placed in the receiver in the same manner as described herein . fluid flow would be directed to the outside of the filters , and the filtered fluid would be collected in the filter cores . the filtered fluid would then be collected and transferred to the processing plant or other line at the end of the pipeline . fig1 is a depiction of an above ground pig launcher associated with a pipeline . the pig launcher 210 is shown with a pig launcher opener 212 in the closed position . a holder 214 is shown with a filter cartridge carrier assembly 216 placed adjacent to the pig launcher . the filter cartridge carrier assembly 216 can be easily accessed to place into the pig launcher when needed . bypass line 218 is also shown . flange connection 220 that would be modified to include the sump plate used with this invention is also shown . the other piping and valves are those typical to this type of installation .