Abstract:
Methods and systems are disclosed for treating a drilling fluid mixture including feeding the drilling fluid mixture to a hydrocyclone (or hydrocyclones) with a flow-volume-adjustable inlet for controlling flow of the drilling fluid mixture into the hydrocyclone(s). This abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims, 37 C.F.R. 1.72(b).

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is directed to drilling fluid processing systems; to hydrocyclones used in such processing; to such hydrocyclones with a selectively adjustable inlet for drilling fluid; and to methods for using such systems and such hydrocyclones. 
     2. Description of the Related Art 
     In the drilling of a wellbore, a drill bit attached to the lower end of a drill string is rotated and lowered to form a hole in the earth. A drilling fluid is circulated through the hole, normally down the drill string to the bottom of the hole and upward through the annulus to the surface of the earth. The drilling fluid is referred to as drilling “mud”. The circulating drilling mud cools and lubricates the drilling bit and drill string, removes earth cuttings and solids from the hole, forms a filter cake on the hole wall, and/or controls formation pressure. Drilled solids can accumulate in the drilling mud and, if not removed, can adversely affect the hole and the drilling operations. 
     There are a variety of known drilling fluid processing systems, including, for example, but not limited to, those in U.S. Pat. Nos. 6,868,972; 6,669,027; 6,662,952; 6,352,159; 6,510,947; 5,861,362; 5,392,925; 5,229,018; 4,696,353; 4,459,207; 4,495,065; 4,446,022; 4,306,974; 4,319,991; and 4,116,288 (all said patents incorporated fully herein for all purposes). 
     Hydrocyclones are used in some known systems and methods to treat drilling muds to remove solids. Some typical hydrocyclones are separators with a separation chamber which, in some systems, is a generally cylindrical and conical separation chamber with an inlet, with an apex outlet located adjacent the apex of the cone, a vortex finder, and a vortex finder outlet located adjacent a base of the cone. Drilling mud is fed into the inlet and the inlet flow is converted into a flow with a tangential velocity along an inside wall of the separation chamber. The circular path of the flow results in centripetal acceleration which is applied to settling velocities of the suspended solids, driving larger and heavier particles outwardly toward the conical wall into an accelerating spiral along the wall to the apex outlet. These solids discharge at the apex of the cone. The liquid phase of the drilling mud, carrying smaller and lighter drilled solids, moves as a spiraling vortex to the vortex finder outlet. 
     U.S. Pat. Nos. 1,832,256; 2,870,990; 2,919,898; 2,941,783; 2,954,871; 3,016,962; 3,025,965; 3,057,476; 3,353,673; 3,358,833; 3,385,437; 3,766,997; 3,887,456; 3,893,914; 3,959,139; 3,964,557; 4,090,523; 4,134,828; 4,175,036; 4,226,708; 4,793,925; 5,108,608; 5,225,082; 5,240,115; 5,560,818; 5,858,237; 6,129,217; 6,533,946; 6,596,169; 6,855,261; 7,293,657; 7,438,142; and U.S. application Ser. No. 11/294,902 filed Dec. 6, 2005, Pub. No. 2008/0135300 published Jun. 12, 2008 disclose hydrocyclones and/or systems and methods which use hydrocyclones to treat drilling fluid—all said patents and said application incorporated fully herein for all purposes. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention, in certain aspects, discloses systems for processing a mixture of drilling fluid and solid material to separate at least one component of the mixture by size and/or by density from the mixture, the systems including: pumping apparatus for pumping a drilling fluid mixture, the drilling fluid mixture containing drilling fluid and solids; a hydrocyclone in fluid communication with the pumping apparatus for receiving the drilling fluid mixture therefrom, the hydrocyclone having an inner chamber and an inlet for the flow of the drilling fluid mixture into the hydrocyclone; the hydrocyclone having adjustment apparatus for adjusting flow of the drilling fluid mixture through the inlet. 
     The present invention discloses, in certain aspects, methods for treating a mixture of drilling fluid and solid material to separate at least one component of the mixture by size and/or by density from the mixture, such a method in one aspect including: feeding the mixture to a system, the system having a hydrocyclone and pumping apparatus for pumping a drilling fluid mixture, the drilling fluid mixture containing drilling fluid and solids, the hydrocyclone in fluid communication with the pumping apparatus for receiving the drilling fluid mixture therefrom, hydrocyclone adjustment apparatus mounted adjacent an inlet for adjusting flow of the drilling fluid mixture through the inlet and into an inner chamber; and adjusting the flow of the mixture into the inner chamber by using the adjustment apparatus adjacent the inlet. 
     The present invention discloses, in certain aspects, systems for processing a mixture of drilling fluid and solid material to separate at least one component of the mixture from the mixture, the systems having: a hydrocyclone (or a plurality of hydrocyclones in series) for receiving a drilling fluid mixture; the hydrocyclone (or each hydrocyclone) having an inner chamber and an inlet with an inlet flow channel, the drilling fluid mixture flowable through the inlet flow channel into the inner chamber, and the hydrocyclone (or each hydrocyclone) having adjustment apparatus mounted adjacent the inlet for adjusting flow of the drilling fluid mixture into the inner chamber. In such systems the adjustment apparatus may include a movable closure member movable to adjust effective size of the inlet flow channel; the movable closure member may be movable to close off the inlet flow channel to flow; and/or the inner chamber may be in a housing, the adjustment apparatus further having a movable closure member for adjusting flow through the inlet flow channel, an adjustment member connected to the movable closure member, and part of the adjustment member projecting out from the housing for movement thereof outside the housing to thereby move the movable closure member, either manually or by a control system. 
     Accordingly, the present invention includes features and advantages which are believed to enable it to advance hydrocyclone technology and to advance the processing of drilling fluid with a or several hydrocyclones. Characteristics and advantages of the present invention described above and additional features and benefits will be readily apparent to those skilled in the art upon consideration of the following description of preferred embodiments and referring to the accompanying drawings. 
     Certain embodiments of this invention are not limited to any particular individual feature disclosed here, but include combinations of them distinguished from the prior art in their structures, functions, and/or results achieved. Features of the invention have been broadly described so that the detailed descriptions of embodiments preferred at the time of filing for this patent that follow may be better understood, and in order that the contributions of this invention to the arts may be better appreciated. There are, of course, additional aspects of the invention described below and which may be included in the subject matter of the claims to this invention. Those skilled in the art who have the benefit of this invention, its teachings, and suggestions will appreciate that the conceptions of this disclosure may be used as a creative basis for designing other structures, methods and systems for carrying out and practicing the present invention. The claims of this invention are to be read to include any legally equivalent devices or methods which do not depart from the spirit and scope of the present invention. 
     What follows are some of, but not all, the objects of this invention. In addition to the specific objects stated below for at least certain embodiments of the invention, other objects and purposes will be readily apparent to one of skill in this art who has the benefit of this invention&#39;s teachings and disclosures. It is, therefore, an object of at least certain embodiments of the present invention to provide the embodiments and aspects listed above and: 
     New, useful, unique, efficient, nonobvious drilling fluid processing systems using one or a plurality of hydrocyclones with an adjustable inlet system, and methods of the use of such a hydrocyclone, hydrocyclones, or a series thereof. 
     The present invention recognizes and addresses the problems and needs in this area and provides a solution to those problems and a satisfactory meeting of those needs in its various possible embodiments and equivalents thereof. To one of skill in this art who has the benefits of this invention&#39;s realizations, teachings, disclosures, and suggestions, various purposes and advantages will be appreciated from the following description of certain preferred embodiments, given for the purpose of disclosure, when taken in conjunction with the accompanying drawings. The detail in these descriptions is not intended to thwart this patent&#39;s object to claim this invention no matter how others may later attempt to disguise it by variations in form, changes, or additions of further improvements. 
     The Abstract that is part hereof is to enable the U.S. Patent and Trademark Office and the public generally, and scientists, engineers, researchers, and practitioners in the art who are not familiar with patent terms or legal terms of phraseology to determine quickly, from a cursory inspection or review the nature and general area of the disclosure of this invention. The Abstract is neither intended to define the invention, which is done by the claims, nor is it intended to be limiting of the scope of the invention or of the claims in any way. 
     It will be understood that the various embodiments of the present invention may include one, some, or all of the disclosed, described, and/or enumerated improvements and/or technical advantages and/or elements in claims to this invention. 
     Certain aspects, certain embodiments, and certain preferable features of the invention are set out herein. Any combination of aspects or features shown in any aspect or embodiment can be used except where such aspects or features are mutually exclusive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more particular description of embodiments of the invention briefly summarized above may be had by references to the embodiments which are shown in the drawings which form a part of this specification. These drawings illustrate embodiments preferred at the time of filing for this patent and are not to be used to improperly limit the scope of the invention which may have other equally effective or legally equivalent embodiments. 
         FIG. 1  is a schematic view of a system according to the present invention with a hydrocyclone according to the present invention. 
         FIG. 2A  is a perspective view of a hydrocyclone according to the present invention. 
         FIG. 2B  is a cross-section view of the hydrocyclone of  FIG. 2A . 
         FIG. 2C  is a cross-section view along line  2 C- 2 C of  FIG. 2B . 
         FIG. 3A  is a partial view in cross-section of a hydrocyclone according to the present invention. 
         FIG. 3B  is a cross-section view of the hydrocyclone of  FIG. 3A  showing an inlet opening closed to flow. 
         FIG. 3C  is a partial perspective view of an embodiment of a hydrocyclone according to the present invention as in  FIG. 3A . 
         FIG. 3D  is a partial perspective view of the hydrocyclone as shown in  FIG. 3C  with an inlet opening closed off to flow. 
         FIG. 3E  is a cross-sectional view of an exemplary inlet passageway according to one embodiment of the present invention. 
         FIG. 4A  is a partial view in cross-section of a hydrocyclone according to the present invention. 
         FIG. 4B  is a cross-section view of the hydrocyclone of  FIG. 4A  showing an inlet opening closed to flow. 
         FIG. 5A  is a partial view in cross-section of a hydrocyclone according to the present invention. 
         FIG. 5B  is a cross-section view of the hydrocyclone of  FIG. 5A  showing an inlet opening closed to flow. 
         FIG. 5C  is a partial perspective view of the hydrocyclone of  FIG. 5A . 
         FIG. 5D  is a partial perspective view of the hydrocyclone of  FIG. 5A . 
         FIG. 6A  is a cross-section view of a hydrocyclone (shown partially) according to the present invention. 
         FIG. 6B  is a cross-section view of a hydrocyclone (shown partially) according to the present invention. 
         FIG. 6C  is a cross-section view of a hydrocyclone (shown partially) according to the present invention. 
         FIG. 6D  is a cross-section view of a hydrocyclone (shown partially) according to the present invention. 
         FIG. 7  is a schematic view of a system according to the present invention with multiple hydrocyclones according to the present invention. 
         FIG. 8A  is a top perspective view of a hydrocyclone according to the present invention. 
         FIG. 8B  is a top perspective view of the hydrocyclone of  FIG. 8A . 
         FIG. 8C  is an enlarged perspective view of part of the hydrocyclone shown in  FIG. 8B . 
         FIG. 8D  is an enlarged perspective view of part of the hydrocyclone shown in  FIG. 8A . 
         FIG. 8E  is a top view of the part shown in  FIG. 8D . 
         FIG. 9  is a perspective view of a hydrocyclone according to the present invention. 
         FIG. 9A  is an exploded view of the hydrocyclone of  FIG. 9 . 
     
    
    
     Certain embodiments of the invention are shown in the above-identified figures and described in detail below. Various aspects and features of embodiments of the invention are described below and some are set out in the dependent claims. Any combination of aspects and/or features described below or shown in the dependent claims can be used except where such aspects and/or features are mutually exclusive. It should be understood that the appended drawings and description herein are of certain embodiments and are not intended to limit the invention or the appended claims. On the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the appended claims. In showing and describing these embodiments, like or identical reference numerals are used to identify common or similar elements. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness. 
     As used herein and throughout all the various portions (and headings) of this patent, the terms “invention”, “present invention” and variations thereof mean one or more embodiments, and are not intended to mean the claimed invention of any particular appended claim(s) or all of the appended claims. Accordingly, the subject or topic of each such reference is not automatically or necessarily part of, or required by, any particular claim(s) merely because of such reference. So long as they are not mutually exclusive or contradictory any aspect or feature or combination of aspects or features of any embodiment disclosed herein may be used in any other embodiment disclosed herein. 
     DETAILED DESCRIPTION OF THE INVENTION 
     What follows are the descriptions of embodiments preferred at the time of filing for this patent. 
     The system  500  according to the present invention shown in  FIG. 1  includes a derrick  502  from which extends a drillstring  504  into the earth  506 . The drillstring  504 , as is well known, can include drill pipes and drill collars. A drill bit  512  is at the end of the drillstring. A rotary system  514 , top drive system  526 , and/or a downhole motor  532  (“fluid motor”, “mud motor”) may be used to rotate the drillstring  504  and the drill bit  512 . A typical drawworks  516  has a cable or rope apparatus  518  for supporting items in the derrick  502 . A system with one, two, or more mud pump systems  521  supplies drilling fluid  524  to the drillstring  504 . Drilling forms a wellbore  530  extending down into the earth  506 . 
     During drilling, the drilling fluid  524  is pumped by the pumps  521  into the drillstring  504 . Drilling fluid  524  flows to the drill bit  512 , and then flows into the wellbore  530  through passages in the drill bit  512 . Circulation of the drilling fluid  524  transports earth and/or rock cuttings, solids, debris, etc. from the bottom of the wellbore  530  to the surface through an annulus  527  between a well wall of the wellbore  530  and the drillstring  504 . The cuttings, solids, etc. are removed from the drilling fluid  524  in a processing system  522  which includes at least one (or a plurality of) hydrocyclone  510  according to the present invention so that re-usable drilling fluid may be re-circulated from a mud pit  529  by the pumps  521  back to the drillstring  504 . 
       FIGS. 2A and 2B  show a hydrocyclone  10  according to the present invention which has a housing  12 , an inner chamber  14 , an inlet  16 , with an opening  15 , an outlet  17 , (sometimes referred to as a “vortex finder,” “vortex outlet,” or “vortex finder outlet”) an outlet (or apex)  18  and adjustment apparatus  20 . The adjustment apparatus  20  (which may be any adjustment apparatus disclosed herein according to the present invention) is movable to selectively and controllably vary the effective size of the cross-sectional area of the opening  15  to control a flow of a drilling fluid mixture  11  into the inner chamber  14 . 
     Optionally, the adjustment apparatus  20  is manually adjustable with an adjustment mechanism  13  (shown schematically,  FIG. 2C ). Optionally, a control system  26  is in communication with a sensor or sensors  28   a  (e.g. a sensor or sensors for sensing fluid pressure of the inlet feed) and/or sensors  28   b  located outside the inlet which sense position of and/or stress on the adjustment apparatus  20  and/or rotation of a shaft  20   s ; e.g., torsion spring(s), proximity switches(es), pressure gaug(es), and/or strain gauge(s). The apparatus  20  is on a shaft  20   s  and includes movement apparatus  29  for moving the adjustment apparatus  20 . The control system  26  controls the adjustment apparatus  20  and the apparatus  29 . In one aspect, the control system  26  includes computing apparatus  26   c  (e.g., a laptop computer, a desktop computer, a PLC, multiples of any of these, etc.) for computer control of the adjustment apparatus, including in one aspect, automatic control thereof. (Lines with arrows connected to the system  26 ,  FIG. 2B , indicate lines to sensors and to apparatus  29 .) Any system herein can have one, some, or all such sensors as described herein; and, thus, the position of a movable closure member for adjusting effective size of a flow inlet can be controlled in response to the pressure (constant or variable) of flow in direction opening or closing the inlet or in response to force (constant or variable) in a direction opening or closing the inlet—and this can be computer controlled. 
       FIGS. 3A and 3B  illustrate an adjustment apparatus  30  according to the present invention for changing the size of an opening  15   a  (like the opening  15 ,  FIG. 2C ) of an inlet  16   a  (like the inlet  16 ,  FIG. 2B ) of a hydrocyclone having a housing  12   a  (like the housing  12 ,  FIG. 2A ) with an inner chamber  14   a  (like the inner chamber  14 ,  FIG. 2B ). A closure toe  31  is pivotably connected to a rotatable shaft  32  by a key  33 . The shaft  32 , rotatably connected to the housing  12   a , projects from the housing  12   a  for manual or controlled rotation to change the effective size of the opening  15   a . As shown in  FIG. 3B , the opening  15   a  may be closed off totally. 
       FIGS. 3C and 3D  show a hydrocyclone like that of  FIGS. 3A and 3B  (like numerals indicate like parts) with an adjustment apparatus  30   a  (like the apparatus  30 ) which selectively closes off an inlet passageway  15   b  with a generally rectangular cross-section, as shown in  FIG. 3E . 
       FIGS. 4A and 4B  show an adjustment apparatus  40  according to the present invention for changing the size of an opening  15   b  (like the opening  15 ,  FIG. 2C ) of an inlet  16   b  (like the inlet  16 ,  FIG. 2B ) of a hydrocyclone having a housing  12   b  (like the housing  12 ,  FIG. 2A ) with an inner chamber  14   b  (like the inner chamber  14 ,  FIG. 2B ). 
     A pin  41  pivotably connects a closure toe  42  to the housing  12   b . A flexible bar  43  extending into and connected at one end to the closure toe  42  has another end within a recess  45   a  and abutting a rotatable shaft  44 . The shaft  44  is connected to the housing  12   b . A portion of the flexible bar  43  extends through a chamber  45  of the housing  12   b.    
     The flexible bar  43  is flexed, as shown in  FIG. 4A , due to the force and/or pressure of a drilling fluid mixture flowing into the inlet  16   b  and through the opening  15   b  into the inner chamber  14   b . As the force and/or pressure of flow decreases, the flexible bar  43  flexes less, partially closing off the opening  15   b . When the spring force of the flexible bar  43  is not overcome by the force and/or pressure of flow, it moves the closure toe  42  to close off the opening  15   b  entirely (see  FIG. 4B ). 
     In one aspect the shaft  44  has an eccentric surface  44   s  that presses against the flexible bar  43  bending the bar  43 . As shown in  FIG. 4B , the bar  43  is flexed to its greatest extent. The shaft  44  can be rotated to change the amount of pressure applied by the toe  42  while the hydrocyclone is in operation. Rotating the shaft  44  to an intermediate position (intermediate those of  FIGS. 4A and 4B ) results in different amounts of closure pressure applied to the bar  43  and, thus, to the toe  42 , at any given position. The shaft  44 , therefore, acts as a cam shaft for adjusting the amount of force needed to change the size of the opening  15   b.    
     In one particular aspect, the shaft  44  extends from the housing  12   b  for connection to a control system for controlled rotation or for manual rotation. 
       FIGS. 5A-5D  show an adjustment apparatus  50  according to the present invention for changing the effective size on an opening  15   c  (like the opening  15 ,  FIG. 2C ) of an inlet  16   c  (like the inlet  16 ,  FIG. 2B ) of a hydrocyclone having a housing  12   c  (like the housing  12 ,  FIG. 2A ) with an inner chamber  14   c  (like the chamber  14 ,  FIG. 2B ). The inlet passage is open in  FIGS. 5A and 5C  and closed to flow in  FIGS. 5B and 5D . 
     A closure toe  52  has a movable wall  51  pivotably connected to the housing  12   c  with a pivot pin  54  and a movable wall  53  pivotably connected to the housing  12   c  with a pivot pin  55 . The walls contact, but are not connected together, at a point  52   p . In one aspect, an optional spring  51   s  pulls the walls  51 ,  53  together. The two pivot points, which do not project out from the surfaces near them, make it possible to have relatively smooth surfaces adjacent the pivot points for the interior of the hydrocyclone&#39;s separation chamber (e.g. a chamber  14 ,  FIG. 2B ) and a relatively smooth surface for the inlet. Smoother surfaces reduce unwanted turbulence. A shaft  50   t  (see  FIGS. 5C ,  5 D) connected to the pivot pin  55  projects from the housing  12   c  for manual or controlled opening and closing of the inlet passageway. 
     A selectively inflatable air bladder  56  in a chamber  57  in the body  12   c , when deflated, allows the closure toe  52  to remain in an open position as shown in  FIG. 5A  with the opening  15   c  open. As the bladder  56  is inflated, the closure toe moves to close off the opening  15   c . If the bladder  56  is inflated to the extent shown in  FIG. 5B , the closure toe  52  closes off the opening  15   c  entirely. 
     Air is supplied through appropriate conduits to the bladder  56  from an external air supply  58  controlled by a control system  59  (and/or with a manually-operable valve apparatus VA). 
     It is within the scope of the present invention for a closure structure (e.g. any closure toe herein) to have any desired shape and/or cross-sectional shape for effecting partial and/or total closing off of the flow area of a hydrocyclone&#39;s inlet.  FIGS. 6A-6D  illustrate hydrocyclones  61 - 64  according to the present invention each with an inlet  61   i - 64   i , respectively, each with a closure structure  61   s - 64   s , respectively. As shown the closure structures  61   s - 64   s  have different cross-sectional shapes and occupy different areas of openings. 
     As shown in  FIG. 6A , the closure structure  61   s  is connected to a rotatable shaft  61   r  which extends outside of a housing  61   h . The shaft  61   r  can be manually rotated or automatically rotated by an optional control system  61   t.    
     In certain prior known hydrocyclones, when the feed flow rate is reduced, the feed velocity is also reduced. In other words, a smaller volume of feed per unit of time (cubic inches per minute, for example) travels through a passageway having a constant inlet cross-sectional area (in square inches), resulting in a lower velocity (in inches/minute). When the inlet velocity drops, separation performance of the hydrocyclone can suffer dramatically, and can even reach the point of total failure. In hydrocyclones according to the present invention, when the feed flow rate is reduced, the feed velocity can be maintained. A change in feed flow to smaller volume per unit of time (e.g., cubic inches per minute) is forced to travel through a smaller inlet passageway, with a reduced cross-sectional area (e.g. in square inches), resulting, in one aspect, in maintaining a constant velocity (e.g. in inches/minute). 
     In various aspects and embodiments of the present invention the position of a closure toe (e.g. any closure toe or structure in any embodiment of the present invention) at any given time may be controlled using a mechanism sensitive to pressure, sensitive to force, or both (e.g. a spring, an inflatable bladder), that provides: 
     a. constant pressure in the direction closing the inlet; 
     b. constant pressure in the direction opening the inlet; 
     c. variable pressure in the direction closing the inlet; 
     d. variable pressure in the direction opening the inlet; 
     e. computer controlled pressure in the direction closing the inlet; 
     f. computer controlled pressure in the direction opening the inlet; 
     g. constant force in the direction closing the inlet; 
     h. constant force in the direction opening the inlet; 
     I. Variable force in the direction closing the inlet; 
     j. variable force in the direction opening the inlet; 
     k. computer controlled force in the direction closing the inlet; or 
     l. computer controlled force in the direction opening the inlet. 
     As shown, e.g., in  FIGS. 3B ,  4 B and  5 B, an adjustment apparatus in a hydrocyclone according to the present invention can completely close off an inlet, shutting off flow to that hydrocyclone. In one aspect, the toe subsequently opens the inlet opening once a suitably high target feed pressure is achieved. In one aspect, systems according to the present invention with relatively inexpensive control elements, (e.g. a spring) can have closure toe pressure settings installed by design. For a system as in  FIG. 7  with multiple hydrocyclones HC according to the present invention, these options are possible using a hydrocyclone or hydrocyclones according to the present invention: 
     a. As feed volume increases, various pressure settings for the closure toes allow one or more hydrocyclone inlets to open; 
     b. As feed volume increases, the first hydrocyclone(s) to open (e.g. those with lower pressure settings for the closure toe) have one particular cylindrical body diameter, while the next hydrocyclone(s) to open (as the feed pressure increases), have second or third cylindrical body diameter values different from the first diameter; 
     c. As feed volume increases, the first hydrocyclone(s) to open (e.g. those with lower pressure settings for the closure toe) have one particular first vortex finder length, while the next hydrocyclone(s) to open (as the feed pressure increases), have second or third vortex finder length values different from the first length; 
     d. As feed volume increases, the first hydrocyclone(s) to open (those with lower pressure settings for the closure toe) have one particular first vortex finder diameter, while the next hydrocyclone(s) to open (as the feed pressure increases), have second or third vortex finder diameter values different from the first diameter; 
     e. As feed volume increases, the first hydrocyclone(s) to open (those with lower pressure settings for the closure toe) have one particular first cone angle, while the next hydrocyclone(s) to open (as the feed pressure increases), have second or third cone angle values different from the first; 
     f. As feed volume increases, the first hydrocyclone(s) to open (those with lower pressure settings for the closure toe) have one particular first cone length, while the next hydrocyclone(s) to open (as the feed pressure increases), have second or third cone length values different from the first; 
     g. As feed volume increases, the first hydrocyclone(s) to open (those with lower pressure settings for the closure toe) have one particular first apex diameter, while the next hydrocyclone(s) to open (as the feed pressure increases), have second or third apex diameter values different from the first; 
     h. As feed volume increases, the first hydrocyclone(s) to open (those with lower pressure settings for the closure toe) have one particular first combination of geometric features as in b-g above while the next hydrocyclone(s) to open (as the feed pressure increases), have a second or third combination of values for the geometric features different from the first. 
     Examples of various dimensions are as follows: 
     a. cylindrical body diameter—“cb,”  FIG. 6B . 
     b. vortex finder length—“vfl,”  FIG. 6B . 
     c. vortex finder diameter—“vfd,”  FIG. 6B . 
     d. cone angle—angle “ca,”  FIG. 2B . 
     e. cone length—“cl,”  FIG. 2B . 
     f. apex diameter—“ad,”  FIG. 6B . 
     Optionally, the control strategies described in a-h above are, in one aspect, incorporated in the programming of a process control computing apparatus CP ( FIG. 7 ) of a control system CL and al the closure toes are controlled accordingly. 
       FIGS. 8A-8E  illustrate a hydrocyclone  70  (shown partially) with a chamber  72  in a housing  73  into which material is fed through an inlet  74  with an inlet passageway  75 . The hydrocyclone  70  has a vortex finder outlet (not shown; e.g. as in any system described herein) and a lower outlet  76 . 
     A flexible closure member  80  is secured to a wall  77  of the inlet  74 . The member  80  is movable to close off the passageway  75 . Shafts  78  (not shown in  FIGS. 8A ,  8 B 0  connected to a bar  79  project outside the hydrocyclone  70  for manual or automatically-controlled selective movement of the member  80 . The bar  79  pushes against the member  80  to move the member  80  as shown in  FIGS. 8A ,  8 D and  8 E. 
     As shown in  FIGS. 8B and 8C , the member  80  is positioned so that flow through the passageway  75  is possible. As show in  FIGS. 8A ,  8 D, and  8 E, the member  80  has been moved so that a part  81  thereof sealingly contacts a wall  71  of the inlet  74  shutting off flow through the passageway  75 . 
       FIGS. 9 and 9A  show a hydrocyclone  90  according to the present invention (exploded view in  FIG. 9A ) which has a housing  91  with an inlet  92 , a lower outlet  93  and a vortex finder outlet structure  94 . A closure apparatus  100  selectively closes off a flow passageway  95  of the inlet  92 . 
     The closure apparatus  100  has a movable toe  102  secured to a rotatable shaft  104 . Optionally, a top  106  of the shaft  104  projects from the housing  91  for manual shaft rotation or for interconnection with an automatic control system. 
     Any closure apparatus or structure disclosed herein for any embodiment according to the present invention may be used with the hydrocyclone  90 . 
     The present invention, therefore, provides in some, but not in necessarily all embodiments a system for processing a mixture of drilling fluid and solid material to separate at least one component of the mixture from the mixture, the system including: a hydrocyclone for receiving a drilling fluid mixture; the hydrocyclone having an inner chamber and an inlet with an inlet flow channel, the drilling fluid mixture flowable through the inlet flow channel into the inner chamber; and the hydrocyclone having adjustment apparatus mounted adjacent the inlet for adjusting flow of the drilling fluid mixture into the inner chamber. Such a system may one or some, in any possible combination, of the following: wherein the adjustment apparatus includes a movable closure member movable to adjust effective size of the inlet flow channel; wherein the movable closure member is movable to close off the inlet flow channel to flow; wherein the inner chamber is in a housing and the adjustment apparatus further having a movable closure member for adjusting flow through the inlet flow channel, an adjustment member connected to the movable closure member, part of the adjustment member projecting out from the housing for movement thereof outside the housing to thereby move the movable closure member; wherein the part of the adjustment member projecting out from the housing is manually rotatable; a control system connected to the adjustment apparatus, the control system for automatically moving the part of the adjustment apparatus projecting out from the housing to correspondingly move the movable closure member; first sensor apparatus connected to the housing in communication with the control system, the sensor apparatus for sensing pressure of the drilling fluid mixture in the inlet and for providing a first signal indicative thereof to the control system, the control system for controlling the adjustment apparatus in response to said first signal; second sensor apparatus connected to the housing for sensing a position of the movable closure member, for producing a second signal indicative thereof, and for providing said second signal to the control system, the control system for controlling the adjustment apparatus in response to said second signal; third sensor apparatus connected to the housing for sensing stress on the adjustment apparatus, for producing a third signal indicative thereof, and for providing said third signal to the control system, the control system for controlling the adjustment apparatus in response to said third signal; the adjustment apparatus including a movable closure member movable to adjust effective size of the inlet flow channel, a flexible bar with a first end secured to the movable closure member, the flexible bar having a second end located within and free to move with respect to a recess in the housing, and the flexible bar flexible by the flow of the mixture through the inlet to move the movable closure member in response to flow of the drilling fluid mixture; a bar shaft adjacent the second end of the flexible bar, and the bar shaft rotatable to move the flexible bar thereby moving the movable closure member; the adjustment apparatus including a movable closure member movable to adjust effective size of the inlet flow channel, a first movable wall pivotably connected to the housing, and a selectively inflatable bladder abutting the first movable wall for selectively moving the movable wall to adjust effective size of the inlet; wherein the adjustment apparatus includes a second movable wall, the second movable wall movable with the first movable wall; the adjustment apparatus including the inlet having a first wall spaced-apart from a second wall, a flexible closure member secured to the first wall of the inlet, and the flexible closure member movable to sealingly abut the second wall of the inlet to restrict or close off flow through the inlet; and/or a part contacting the flexible closure member and projecting from the housing, the part movable to move the flexible closure member into contact with the second wall. 
     The present invention, therefore, provides in some, but not in necessarily all embodiments a system for processing a mixture of drilling fluid and solid material to separate at least one component of the mixture from the mixture, the system including: a hydrocyclone for receiving a drilling fluid mixture; the hydrocyclone having an inner chamber and an inlet with an inlet flow channel, the drilling fluid mixture flowable through the inlet flow channel into the inner chamber; the hydrocyclone having adjustment apparatus mounted adjacent the inlet for adjusting flow of the drilling fluid mixture into the inner chamber; the adjustment apparatus including a movable closure member movable to adjust effective size of the inlet flow channel; the movable closure member also movable to close off the inlet flow channel to flow; the inner chamber in a housing and the adjustment apparatus further having an adjustment member connected to the movable closure member, and part of the adjustment member projecting out from the housing for movement thereof outside the housing to thereby move the movable closure member. 
     The present invention, therefore, provides in some, but not in necessarily all embodiments a system with a plurality of hydrocyclones wherein each hydrocyclone of the plurality of hydrocyclones is a hydrocyclone according to the present invention, the top outlet flow of each hydrocyclone except a last hydrocyclone fed in series to another hydrocyclone of the plurality of hydrocyclones, each top outlet flow with particles therein. In such a system the adjustment apparatus of each hydrocyclone can include a closure member movable to adjust effective size of the inlet and as feed volume increases, the hydrocyclones can operate in accord with one of the schemes disclosed herein. 
     The present invention, therefore, provides in some, but not in necessarily all embodiments a method for treating a mixture of drilling fluid and solid material to separate at least one component of the mixture from the mixture, the drilling fluid mixture containing drilling fluid and solids, the method including feeding the mixture to a hydrocyclone according to the present invention and adjusting the flow of the mixture into the inner chamber by moving an adjustment apparatus according to the present invention. 
     In conclusion, therefore, it is seen that the present invention and the embodiments disclosed herein and those covered by the appended claims are well adapted to carry out the objectives and obtain the ends set forth. Certain changes can be made in the subject matter without departing from the spirit and the scope of this invention. It is realized that changes are possible within the scope of this invention and it is further intended that each element or step recited in any of the following claims is to be understood as referring to the step literally and/or to all equivalent elements or steps. The following claims are intended to cover the invention as broadly as legally possible in whatever form it may be utilized. The invention claimed herein is new and novel in accordance with 35 U.S.C. §102 and satisfies the conditions for patentability in §102. The invention claimed herein is not obvious in accordance with 35 U.S.C. §103 and satisfies the conditions for patentability in §103. This specification and the claims that follow are in accordance with the requirements of 35 U.S.C. §112. The inventors may rely on the Doctrine of Equivalents to determine and assess the scope of their invention and of the claims that follow as they may pertain to apparatus and/or methods not materially departing from, but outside of, the literal scope of the invention as set forth in the following claims. All patents and applications identified herein are incorporated fully herein for all purposes. It is the express intention of the applicant not to invoke 35 U.S.C. §112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function. In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements. 
     Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention.