Patent Publication Number: US-7909170-B2

Title: Self-cleaning shaker

Description:
The present application claims priority to U.S. Provisional Patent Application Ser. No. 60/827,560, filed on Sep. 29, 2006, and is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     1. Field of the Disclosure 
     The present disclosure generally relates to methods and apparatuses for cleaning vibratory shakers and vibratory shaker components. More specifically, the present disclosure relates to automated methods and apparatuses for cleaning vibratory shakers and vibratory shaker components. 
     2. Background 
     Oilfield drilling fluid, often called “mud,” serves multiple purposes in the industry. Among its many functions, the drilling mud acts as a lubricant to cool rotary drill bits and facilitate faster cutting rates. Typically, the mud is mixed at the surface and pumped downhole at high pressure to the drill bit through a bore of the drillstring. Once the mud reaches the drill bit, it exits through various nozzles and ports where it lubricates and cools the drill bit. After exiting through the nozzles, the “spent” fluid returns to the surface through an annulus formed between the drillstring and the drilled wellbore. 
     Furthermore, drilling mud provides a column of hydrostatic pressure, or head, to prevent “blow out” of the well being drilled. This hydrostatic pressure offsets formation pressures thereby preventing fluids from blowing out if pressurized deposits in the formation are breeched. Two factors contributing to the hydrostatic pressure of the drilling mud column are the height (or depth) of the column (i.e., the vertical distance from the surface to the bottom of the wellbore) itself and the density (or its inverse, specific gravity) of the fluid used. Depending on the type and construction of the formation to be drilled, various weighting and lubrication agents are mixed into the drilling mud to obtain the right mixture. Typically, drilling mud weight is reported in “pounds,” short for pounds per gallon. Generally, increasing the amount of weighting agent solute dissolved in the mud base will create a heavier drilling mud. Drilling mud that is too light may not protect the formation from blow outs, and drilling mud that is too heavy may over invade the formation. Therefore, much time and consideration is spent to ensure the mud mixture is optimal. Because the mud evaluation and mixture process is time consuming and expensive, drillers and service companies prefer to reclaim the returned drilling mud and recycle it for continued use. 
     Another significant purpose of the drilling mud is to carry the cuttings away from the drill bit at the bottom of the borehole to the surface. As a drill bit pulverizes or scrapes the rock formation at the bottom of the borehole, small pieces of solid material are left behind. The drilling fluid exiting the nozzles at the bit acts to stir-up and carry the solid particles of rock and formation to the surface within the annulus between the drillstring and the borehole. Therefore, the fluid exiting the borehole from the annulus is a slurry of formation cuttings in drilling mud. Before the mud can be recycled and re-pumped down through nozzles of the drill bit, the cutting particulates must be removed. 
     Apparatus in use today to remove cuttings and other solid particulates from drilling fluid are commonly referred to in the industry as “shale shakers.” A shale shaker, also known as a vibratory separator, is a vibrating sieve-like table upon which returning solids laden drilling fluid is deposited and through which clean drilling fluid emerges. Typically, the shale shaker is an angled table with a generally perforated filter screen bottom. Returning drilling fluid is deposited at the feed end of the shale shaker. As the drilling fluid travels down the length of the vibrating table, the fluid falls through the perforations to a reservoir below leaving the solid particulate material behind. The vibrating action of the shale shaker table conveys solid particles left behind until they fall off the discharge end of the shaker table. The above described apparatus is illustrative of one type of shale shaker known to those of ordinary skill in the art. In alternate shale shakers, the top edge of the shaker may be relatively closer to the ground than the lower end. In such shale shakers, the angle of inclination may require the movement of particulates in a generally upward direction. In still other shale shakers, the table may not be angled, thus the vibrating action of the shaker alone may enable particle/fluid separation. Regardless, table inclination and/or design variations of existing shale shakers should not be considered a limitation of the present disclosure. 
     Preferably, the amount of vibration and the angle of inclination of the shale shaker table are adjustable to accommodate various drilling fluid flow rates and particulate percentages in the drilling fluid. After the fluid passes through the perforated bottom of the shale shaker, it can either return to service in the borehole immediately, be stored for measurement and evaluation, or pass through an additional piece of equipment (e.g., a drying shaker, centrifuge, or a smaller sized shale shaker) to further remove smaller cuttings. 
     As drilling fluid is processed, residual drilling waste (e.g., high density fluids and particulate matter), may become stuck or entrained on the shaker screens and other internal shaker components. As the amount of residual drilling waste increases, the efficiency of the shale shaker may decrease due to, for example, clogged screens, clogged outlet lines, and/or “gummed up” internal components. To maintain shaker efficiency, the residual drilling waste must be removed from the shaker components. 
     Presently, methods for removing the residual waste include manual spraying of the internal components. These processes are both time intensive and labor intensive. 
     Accordingly, there exists a need for a shale shaker cleaning system that decreases the amount of time the shaking apparatus is out of commission. Additionally, there exists a need for an automated process that decreases the amount of manual labor required to clean the system. 
     SUMMARY OF THE DISCLOSURE 
     In one aspect, embodiments disclosed herein relate to a vibratory separator including a housing having a drilling material inlet and at least one basket, at least one screen assembly configured to be disposed in the at least one basket, an actuator connected to the at least one basket, wherein the actuator provides vibratory motion to the at least one basket, a sump configured to receive drilling material that passes through the at least one screen assembly, and at least one spray nozzle for cleaning the vibratory separator. 
     In another aspect, embodiments disclosed herein relate to method for cleaning a vibratory separator including providing instructions to a programmable logic controller to activate at least one spray nozzle disposed on the vibratory separator. 
     In another aspect, embodiments disclosed herein relate to a method of retrofitting a vibratory separator including installing at least one spray nozzle in a vibratory separator, installing a programmable logic controller on the vibratory separator, and providing instructions to the programmable logic controller to activate at least one spray nozzle disposed on the vibratory separator. 
     Other aspects and advantages of the invention will be apparent from the following description and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a top perspective view of a vibratory separator in accordance with an embodiment of the present disclosure. 
         FIG. 2  is a cross sectional view of an alternate vibratory separator in accordance with an embodiment of the present disclosure. 
         FIG. 3  is a cross sectional view of a vibratory separator in accordance with an embodiment of the present disclosure. 
         FIG. 4  is a cross sectional view of a vibratory separator in accordance with an embodiment of the present disclosure. 
         FIG. 5  is a side perspective view of a vibratory separator in accordance with an embodiment of the present disclosure. 
         FIG. 6  is a cross sectional view of a vibratory separator in accordance with an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Generally, embodiments disclosed herein relate to apparatuses and methods for cleaning vibratory shakers. Furthermore, apparatuses and methods disclosed herein may include at least one spray nozzle and/or vibratory sump for the automated cleaning of vibratory shakers. 
     Referring initially to  FIG. 1 , a top perspective view of a vibratory separator  100  in accordance with one embodiment of the present disclosure is shown. In this embodiment, vibratory separator  100  includes a housing  101  defining a drilling material inlet  102 , a drilling material discharge area  103 , and an inner section  110 . Vibratory separator  100  also includes at least one actuator  104  (e.g., a motor, a motor system, or a motor control device). In this embodiment, actuator  104  is coupled to a rotary motor (not shown), which upon engagement, imparts a vibratory motion to a basket  105  that is disposed within housing  101 . 
     Securely attached to basket  105  is at least one screen assembly  106 . Screen assembly  106  is secured, such that as actuator  104  is engaged, and vibratory basket  105  begins to vibrate, screen assembly  106  will not loosen from basket  105 . Screen assembly  106  may be made from any material known to one of ordinary skill in the art including, but not limited to, steel, composite, mesh, and cloth. Moreover, screen assembly  106  may be connected to vibratory separator  100  by any connection type known to one of ordinary skill in the art including, for example, pretension and/or hookstrip assemblies. 
     Located below screen assembly  106  is a sump  107 . As drilling material, including liquid state and solid state particulate matter, flows through screen assembly  106 , the drilling material may collect in sump  107 . When sump  107  becomes full, or at the discretion of the drilling operator, sump  107  may be emptied through an outlet (not shown). In alternate embodiments, the outlet to sump  107  may include a valve for retaining drilling waste in sump  107 . Thus, sump  107  may serve as a means for collecting drilling material that has passed through screen assembly  106 , as well as serving as a storage vessel for separated drilling material prior to downstream processing. 
     As drilling material collects in the bottom of vibratory separator  100 , some material may become stuck to the sidewalls and bottom of sump  107 . To prevent the build up of material in sump  107 , in certain embodiments, sump  107  may be attached to actuator  104  to providing vibratory motion to sump  107 . As vibratory motion is applied to sump  107 , material stuck to the sidewalls and bottom of sump  107  may be dislodged, thereby allowing the material to exit vibratory separator  100  through the outlet (not shown). In alternate embodiments, the vibratory motion to sump  107  may be provided through an alternate actuator disposed either internal or external to vibratory separator  100 . That is, separate actuators may provide vibratory motion to basket  105  and sump  107 . 
     While vibratory motion may dislodge material from the sidewalls and bottom of sump  107 , in certain embodiments, material may be stuck to sump  107  so that vibratory motion alone will not dislodge the material. In such embodiments, nozzles (not shown) disposed on inner section  110  of vibratory separator  100  may provide a cleaning fluid to assist in removing the material from sump  107 . The cleaning fluid may include water, surfactants, steam, and/or any other dissolving fluids known to those of ordinary skill in the art. In certain embodiments, the cleaning fluid may be pressurized or heated to further assist in removing drilling material from sump  107 . Thus, vibratory separators  100  in accordance with embodiments of the present disclosure may also include attachments for pressurization units (e.g., compressors) and/or heating units (e.g., boilers). Additionally, vibratory separator  100  may also include a programmable logic controller (“PLC”)  108 . PLC  108  may include instructions for running actuators  104 , nozzles, pressurization units, heating units, vibratory sump actuators, or any other process that may require instructions for automation. However, in other embodiments, the nozzles, pressurization units, heating units, sump actuators, and other processes may be controlled manually through the use of, for example, manually valves or control switches. 
     Now referring to  FIG. 2 , a cross sectional view of an alternate vibratory separator  200  in accordance with one embodiment of the present disclosure is shown. In this embodiment, vibratory separator  200  includes a housing  201 , a drilling material inlet  202 , a screen assembly  206 , a sump  207 , and an outlet  211 . Additionally, the present embodiment includes a plurality of nozzles  212  disposed along the interior of housing  201 . As drilling material enters vibratory shaker  200  through inlet  202 , the drilling material falls onto screen assembly  206  and is conveyed from an inlet end  213  toward a discharge end  214  using vibratory motion as described above. As screen assembly  206  vibrates, residual drilling fluid and small particulate matter may fall through screen assembly  206  into sump  207 . As drilling material sticks to and collects to sump  207 , the drilling material may begin to clog outlet  211  or otherwise prevent the flow of drilling material to downstream processing equipment. In certain embodiments, one of ordinary skill in the art will appreciate that the addition of a valve  214  on outlet  211  may help a drilling operator control the flow of drill material from sump  207 . 
     In such an embodiment, when sump  207  is substantially full of drilling material, or at a time interval as determined by the drilling operator, valve  214  may be opened to allow the drilling material to exit sump  207 . Before, during, and/or after opening valve  214 , thereby allowing drilling material to flow from sump  207 , a flow of cleaning fluid may be provided from nozzles  212 . In this embodiment, nozzles  212  are illustrated disposed in the corners of housing  201  of vibratory separator  200 . As such, nozzles  212  are directed to provide a flow of cleaning fluid over screen assembly  206 . However, one of ordinary skill in the art will appreciate that nozzles  212  may be positioned to direct a flow of cleaning fluid to any surface area on the interior of housing  201 , including, but not limited to, screen assembly  206 , sump  207 , outlet  211 , and any additional areas that may be present in vibratory separator  200 . 
     In an alternate embodiment, valve  214  may remain open during the operation of vibratory separator  200  to allow a continuous flow of drilling material from vibratory separator  200  to downstream equipment. In such an embodiment, drilling material may continue to flow from vibratory separator  200 , and nozzles  212  may be activated when sump  207  begins to overflow, when outlet  211  become clogged, and/or when screen assembly  206  becomes coated with drilling material such that the flow of drilling material therethrough is impeded. In either of the above mentioned embodiments, one of ordinary skill in the art will appreciate that the cleaning provided by the directed spray of cleaning fluid from nozzles  212  to the interior of vibratory separator  200  may be further enhanced by providing a vibratory motion to sump  207 , as discussed above. 
     Referring to  FIG. 3 , a cross sectional view of a vibratory separator  300  in accordance with another embodiment of the present disclosure is shown. In this embodiment, vibratory separator  300  includes a housing  301 , a drilling material inlet  302 , a screen assembly  306 , a sump  307 , and an outlet  311 . Additionally, the present embodiment includes a plurality of nozzles  312  disposed along the interior of housing  301 . As illustrated, outlet  311  includes a plurality of valves  316  which may be actuated to direct an exiting flow of drilling material from vibratory separator  300  to either downstream processing equipment and/or a remediation device. 
     Outlet  311  is separated into two directional outlet lines  315  including a line that leads to downstream processing equipment  315   a , and a line that leads to a remediation device  315   b . The flow of material through each outline line  315  may be controlled with corresponding outline line valves  316   a  and  316   b . As drilling material enters vibratory shaker  300  through inlet  302 , the drilling material falls onto screen assembly  306  and is conveyed from an inlet end  313  toward a discharge end  314  using vibratory motion as described above. As screen assembly  306  vibrates, residual drilling fluid and small particulate matter may fall through screen assembly  306  into sump  307 . As drilling material sticks to and collects to sump  307 , the drilling material may begin to clog outlet  311 . In systems wherein drilling material is allowed to continuously flow out of vibratory separator  300 , as well as in systems where the flow of drilling material is controlled by valves  316 , one of ordinary skill in the art will appreciate that it may be desirable to prevent the contamination of drilling material to be recycled from the cleaning fluids used to clean vibratory separator  300 . 
     To prevent the contamination of drilling material to be recycled from cleaning fluids, a series of valves may be used to control the flow of fluids and particulate matter from vibratory separator  300 . In such an embodiment, during the normal operation of cleaning drilling fluid, outlet valve  316   b  may remain closed to prevent the flow of drilling materials through outline line  315   b , while outlet valve  316   a  may remain open to allow the flow of drilling materials through outline line  315   a . As sump  307  becomes clogged with drilling material, or at a specified cleaning interval as determined by a drilling operator, valve  316   a  may be closed to prevent the flow of drilling materials therethrough, while valve  316   b  is opened to allow cleaning fluids to flow to remediation equipment (not shown). By allowing drilling material that may be recycled into reusable drilling fluid to remain separate from cleaning materials that may include substances that may damage the drilling fluid properties, the integrity of the drilling material may be maintained. 
     Additionally, nozzles  312  in vibratory separator  300  are disposed under screen assembly  306  to allow the direct flow of cleaning fluid into sump  307 . In this embodiment, a high pressure flow of cleaning fluid may further assist in cleaning the area under screen  306 , as well as sump  307 . One of ordinary skill in the art will appreciate that any nozzle placement and or sump, including vibratory sumps, may be used in accordance with the above described embodiment. Furthermore, the nozzles may include non-vibrating nozzles that spray in one general direction and fixed vibrating nozzles that may direct cleaning fluid over a respectively wider area. One of ordinary skill in the art will appreciate that certain embodiments may include any number of fixed vibrating and/or non-vibrating nozzles to cover a specified portion of the interior of vibratory separator  300 . Additionally, modifications to the nozzles, or nozzle attachment points may allow nozzles to move along an interior or exterior surface of housing  301  of vibratory separator  300 . Thus, in at least one embodiment, cleaning fluid may be directed to cover substantially the entire interior surface of vibrating separator  300  by using a plurality of fixed vibrating and/or non-vibrating nozzles. 
     Referring now to  FIG. 4 , a cross sectional view of a vibratory separator  400  in accordance with one embodiment of the present disclosure is shown. In this embodiment, vibratory separator  400  includes a housing  401 , a drilling material inlet  402 , a screen assembly  406 , a sump  407 , and an outlet  411 . Additionally, vibratory separator  400  includes a fume hood/outlet  417  connected to housing  401 . As drilling material enters vibratory shaker  400  through inlet  402 , the drilling material falls onto screen assembly  406  and is conveyed from an inlet end  413  toward a discharge end  414  using vibratory motion as described above. As screen assembly  406  vibrates, residual drilling fluid and small particulate matter may fall through screen assembly  406  into sump  407 . To clean vibratory separator  400 , a plurality of nozzles  412  may be activated to direct a flow of cleaning fluid over interior components of vibratory separator  400 . While residual fluids and particulate matter generally fall through screen assembly  406 , and while drilling waste is discharged via discharge end  414 , a pressurized flow of cleaning fluid may cause the aeration of some of the residual fluids and particulate matter in the form of, for example, suspended particulate matter. 
     In embodiments wherein the pressurized flow of water is heated, a directed flow of cleaning fluid may promote the aeration of potentially hazardous materials including, for example, hydrogen sulfide (“H 2 S”) fumes. To prevent such fumes and aerated materials from escaping vibratory separator  400 , housing  401  may include fume hood/outlet  417 . As fumes and aerated particles are ejected in a generally upward direction, fume hood/outlet  417  may pull the aerated particles and fumes inward, thereby trapping the potentially hazardous fumes and/or aerated particles. One of ordinary skill in the art will appreciate that fume hood/outlet  417  may be turned on during any step of the separation process including during normal separation, during cleaning, or substantially continuously. Thus, embodiments including fume hood/outlets  417  may provide for a vibratory separator  400  that is substantially enclosed, thereby preventing the escape of hazardous materials and/or aerated particulate matter into the drilling work space. 
     Referring to  FIGS. 5 and 6  together, a side perspective and cross sectional view of a vibratory separator  500  in accordance with an alternate embodiment of the present disclosure are shown. In this embodiment, vibratory separator  500  includes a housing  501 , a plurality of screen assemblies  506 , a sump  507 , and an outlet  511 . In this embodiment, vibratory separator  500  includes a multi-tier configuration of screen assemblies  506 . By vertically stacking multiple screen assemblies  506 , the footprint of vibratory separator  500  is decreased, thereby providing equivalent separating potential while requiring less space. In vibratory separators  500  using vertically stacked screen assemblies  506 , the size of the apertures in the screens may be varied according to each tier. As drilling material begins to flow from a top tier of vibratory separator  500 , the screen assembly apertures may be substantially greater in size than the apertures of lower screen assemblies. To prevent drilling fluid from falling on lower disposed screen assemblies  506 , a series of flowback pans  518  may be located under screen assemblies  506 . Flowback pans  518  may be directed to deposit drilling material into sump  507 , thereby allowing drilling material to be substantially cleaner at each level of processing. 
     As described above, vibratory separator  500  may include nozzles (not shown) or a fume hood/outlet (not shown) to further assist in cleaning the interior of vibratory separator  500 . One of ordinary skill in the art will appreciate that any of the above described methods for cleaning vibratory separators may be used in multiple tier screen assembly vibratory separators in accordance with embodiments disclosed herein. 
     Embodiments disclosed herein may include a PLC to provide instructions for the automation of vibratory separation and cleaning of a vibratory separator. In one embodiment, the PLC may provide instructions to the vibratory separator to activate a cleaning system according to a selected time interval. The selected time interval may be determined by a drilling operator, or may be selected from a pre-programmed set of instructions for cleaning the vibratory separator at a pre-selected interval. In such embodiments, one of ordinary skill in the art will appreciate that the cleaning cycle may be activated automatically or on an as-needed basis as is determined by the drilling operator. 
     In alternate embodiments, the PLC may provide instructions to the vibratory separator to activate a pre-programmed routine for activating the flow of a cleaning fluid through nozzles, directing the nozzles, or changing the cleaning fluid dispersed by the nozzles. Additionally, the PLC may provide instructions to activate a vibratory motion in a sump as part of a pre-programmed cleaning routine. While programmed time intervals and routines may assist in cleaning the vibratory separator, certain embodiments may require more exact cleaning instructions for providing efficient cleaning. 
     In one embodiment, a programmable logic controller may provide instructions to at least one nozzle when a vibratory performance parameter of the vibratory separator falls below a specified performance level. A vibratory performance parameter may include, for example, a drilling material discharge rate, a sump level, a processing rate, or any other parameter that may effect the efficiency of a vibrating separation operation as known to those of ordinary skill in the art. 
     In an embodiment wherein drilling material discharge rate is measured to determine a performance parameter, the quantity of drilling material discharged from the vibratory separator during a specified time interval may be measured. In certain embodiments, a decreased discharge rate may indicate that screen assemblies are clogged with particulate matter and/or that internal components are coated with drilling material so as to slow the vibratory operation. If the rate of discharge falls below a specified level, the PLC may receive indication (e.g., an input or signal) that the vibratory separator is not operating within a specified performance level, and may decide whether to initiate a cleaning cycle, or otherwise inform a drilling operator of such condition. 
     In alternate embodiments, the PLC may monitor a sump level. In such an embodiment, a level indicator may be disposed in the sump, and when drilling material reaches the level of the indicator, the PLC may receive a signal that the sump is full. Upon receiving such signal, the PLC may then determine whether to initiate a cleaning cycle, or otherwise inform a drilling operator of such condition. In certain embodiments, multiple performance parameters may be monitored to provide the PLC additional information to be used in determining whether to initiate a cleaning cycle. By basing such decision on multiple performance parameters, one of ordinary skill in the art will realize that the chance of false readings that a performance parameter has fallen below a specified level will be reduced. Thus, the overall efficiency of the system may be increased by minimizing downtime due to unnecessary cleaning cycles. 
     One of ordinary skill in the art will appreciate that providing instructions to a PLC for determining a performance parameter of a vibratory separator and installing spray nozzles to activate accordingly may be retrofitted onto existing vibratory separators. One method of retrofitting a vibrating separator may including installing at least one spray nozzle on an existing vibratory separator and installing a PLC on the vibratory separator to provide instructions to activate the at least one spray nozzle. Thus, an existing vibratory separator may be modified to include the efficiency advantages of the present disclosure. One of ordinary skill in the art will further realize that any of the additional modifications including, for example, a vibrating sump and/or a fume hoot/outlet, may also be retrofitted onto an existing vibratory separator to further increase the efficiency of a system. 
     In other embodiments, a PLC may provide instructions to actuate spray nozzles at different locations within the vibratory separator according to a predetermined sequence. Exemplary sequencing may include actuating nozzles to clean the inside of the vibratory separator first, then actuating nozzles inside the sump second. Such a sequence may increase the efficiency of the cleaning operation by cleaning different sections of the separator at different times. Such sequencing may be further enhanced by including sequencing operations with the time based intervals discussed above. 
     Advantageously, embodiments disclosed herein provide apparatuses and methods for cleaning vibratory separators. Because the vibratory separator does not need to be taken apart to clean the internal components, the process of cleaning the separator is faster, thereby resulting in less downtime. Additionally, the cleaning process may be automated so as to remove the manual labor component of the process. Because embodiments in accordance with the present disclosure may be automated to clean the internal components of a vibratory separator according to a specified time interval or process cycle, the vibrating separator may continuously work at a more efficient level. 
     Furthermore, advantageously, embodiments in accordance with the present disclosure may include PLC&#39;s that provide instructions to nozzles for cleaning processes according to vibratory performance parameters of the vibratory separator. Because the vibratory separator may begin a self-cleaning cycle, or otherwise inform a drilling operator when the separator is functioning below a performance level, a problem may be corrected before it substantially effects system performance. Thus, vibratory shakers in accordance with the present disclosure may help maintain efficient discharge rates, thereby increasing the efficiency of the drilling operations. 
     Moreover, embodiments of the present disclosure may include multiple means for emptying the sump, thereby separating recyclable drilling material from drilling material to be sent to remediation. Because recyclable drilling material is separated from cleaning products, the integrity of the drilling material is maintained, thereby further decreasing the cost of drilling operations by allowing a greater quantity of drilling fluid reuse. Finally, advantageously, vibrating separators in accordance with embodiments disclosed herein may include body housings that have fume hood/outlets as well as sumps to trap drilling material whether in solid, liquid, or gaseous state. Because the vibrating separators include methods for trapping aerated particulate matter and potentially hazardous gases generated by the cleaning process, the vibrating operation may be safer and less environmentally damaging. 
     While the present disclosure has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of the present disclosure will appreciate that other embodiments may be devised which do not depart from the scope of the disclosure described herein. Accordingly, the scope of the disclosure should be limited only by the claim appended hereto.