Patent Abstract:
A controller and method of using same are disclosed. Preferably, the controller includes a pilot cartridge housing supporting an invertible pilot cartridge assembly (“cartridge”). The cartridge preferably includes a cartridge body supporting a number of pneumatic seals adjacent the housing, wherein at least two of the seals are diaphragms. The cartridge preferably provides a first pilot activation feature and an opposing second pilot activation feature. The operating mode of the cartridge is determined by a selected orientation of the first pilot activation feature relative to the housing; and preferably the method of operating the controller includes the steps of: selecting an orientation of the first pilot activation feature relative to the housing; setting a span control mechanism to a neutral position relative to the housing; adjusting a float communicating with the cartridge to a neutral position; and adjusting said span control mechanism to determine a response type of said cartridge.

Full Description:
RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 11/495,973 filed Jul. 27, 2006, entitled “Fluid Level Controller.” 
    
    
     FIELD OF THE INVENTION 
     This invention relates to new and useful improvements in fluid level controllers that incorporate pilot pressure control devices. 
     BACKGROUND 
     Controllers are known to utilize pressurized fluid to actuate a unit, such as a motor valve, to control a primary variable condition, such as a fluid level confined within a storage vessel, by maintaining the fluid level within the storage vessel within predetermined limits. Changes in the fluid level within the storage vessel are used by the controller to selectively apply the pressurized fluid to the unit, such as a motor valve controlling the flow of fluid through an inlet line attached to the storage vessel. Other applications and uses for pressurized fluid controllers are well known in the art. 
     One type of pressurized fluid control device is epitomized by the pressure control device disclosed within U.S. Pat. No. 3,120,241 issued to Asbury S. Parks on Feb. 4, 1964 (Parks &#39;241). Although Parks &#39;241 discloses a functional controller, controllers utilizing the technology disclosed by Parks &#39;241 inherently present a number of drawbacks including: the encountering of significant downtime when defective diaphragms need replacement; and the need to reconfigure the pilot pressure control device, which interacts with the fluid level detection mechanism to control the fluid level within the vessel, and to change to operating mode of the controller from a direct mode to an indirect mode. 
     Accordingly, as market pressures continue to demand liquid level controllers that provide lower cost, greater reliability, and improved ease of use, challenges remain and a need persists for improvements in methods and apparatuses for use in fluid level monitoring and control devices. 
     SUMMARY OF THE INVENTION 
     In accordance with preferred embodiments, a controller includes at least a pilot cartridge housing (“cartridge housing”) and an invertible pilot cartridge assembly (“cartridge”) supported by the cartridge housing, in which the cartridge preferably includes a cartridge body supporting a plurality of seals, wherein the seals communicate with the cartridge housing to pneumatically isolate the cartridge form the cartridge housing, and at least two of the seals are diaphragms. The preferred embodiment further includes a base plate supporting the cartridge housing, a linkage shaft communicating with the base plate, and a level adjustment bar secured to the linkage shaft and configured with a transfer linkage configured for selective communication with either a first pilot activation feature provided on a proximal end of the cartridge, or a second pilot activation feature provided on a distal end of the cartridge. The operating mode of the cartridge is determined by an orientation of the first pilot activation feature relative to the housing, and preferably the cartridge responds to an activation of the level adjustment bar by generating a control signal. 
     In an alternate preferred embodiment, a method of operating the controller in a direct operating mode preferably includes the steps of: setting a span control mechanism provided by a first pilot activation feature of the cartridge to a neutral position relative to the cartridge housing supporting the cartridge; adjusting a float communicating with the cartridge to a neutral position relative to the cartridge housing; adjusting the span control mechanism to determine a signal response type of the cartridge; orienting the first pilot activation feature adjacent a detachable cover supported by the cartridge housing to determine a direct operating mode of the cartridge; and securing the detachable cover to the cartridge housing in preparation for operating the controller in the direct operating mode. 
     In an alternative preferred embodiment, a method of operating the controller in an indirect operating mode preferably includes the steps of: setting a span control mechanism provided by a first pilot activation feature of the cartridge to a neutral position relative to a cartridge housing supporting the cartridge; adjusting a float communicating with the cartridge to a neutral position relative to the cartridge housing; adjusting the span control mechanism to determine a signal response type of the cartridge; orienting a second pilot activation feature adjacent a detachable cover supported by the cartridge housing to determine an indirect operating mode of the cartridge; and securing the detachable cover to the cartridge housing in preparation for operating the controller in the indirect operating mode. 
     These and various other features and advantages that characterize the claimed invention will be apparent upon reading the following detailed description and upon review of the associated drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a front elevational view of an embodiment of an inventive fluid level controller. 
         FIG. 2  shows a front elevational view of the controller of  FIG. 1  with the cover removed. 
         FIG. 3  shows a right side elevational view of the controller of  FIG. 1  with the cover partially cutaway. 
         FIG. 4  shows a front elevational, cross-sectional view of an invertible pilot cartridge of the inventive liquid level controller of  FIG. 2 . 
         FIG. 5  shows a front elevational, cross-sectional view of a pilot cartridge housing assembly of the inventive liquid level controller of  FIG. 2 . 
         FIG. 6  illustrates a front elevational, cross-sectional view of the invertible pilot cartridge of the inventive liquid level controller of  FIG. 2 , configured in a direct operation mode. 
         FIG. 7  illustrates a right side elevational, cross-sectional view of the invertible pilot cartridge of the inventive liquid level controller of  FIG. 2 , configured in a direct operation mode. 
         FIG. 8  illustrates a front elevational, cross-sectional view of the invertible pilot cartridge of the inventive liquid level controller of  FIG. 2 , configured in an indirect operation mode. 
         FIG. 9  illustrates a right side elevational, cross-sectional view of the invertible pilot cartridge of the inventive liquid level controller of  FIG. 2 , configured in an indirect operation mode. 
         FIG. 10  reveals a partial cutaway, bottom plan view of the inventive liquid level controller of  FIG. 3 . 
         FIG. 11  reveals a partial cutaway, top plan view of the inventive liquid level controller of  FIG. 1 . 
         FIG. 12  shows a method of using the inventive liquid level controller of  FIG. 1 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to one or more examples of the invention depicted in the figures. Each example is provided by way of explanation of the invention, and not meant as a limitation of the invention. For example, features illustrated or described as part of one embodiment may be used with another embodiment to yield still a different embodiment. Other modifications and variations to the described embodiments are also contemplated within the scope and spirit of the invention. 
     Referring to the drawings,  FIG. 1  shows an inventive fluid level controller  100  (also referred to herein as controller  100 ) that includes a product cover  102  providing viewing apertures for visual access to both a fluid supply pressure gauge  104 , and a fluid signal pressure gauge  106 . The pressure gauges  104  and  106  provide operators of the controller  100  with the current status of the fluid associated with the controller  100 . 
       FIG. 2  shows the controller  100  further includes a base plate  108 , which supports a pilot cartridge housing assembly  110  (also referred to herein as cartridge housing  110 ) and a displacer housing  112 . The cartridge housing  110  includes a main support structure  114 , which provides access apertures for both the pressure gauges  104  and  106 , and a mounting surface for a detachable cover  116 . In a preferred embodiment the detachable cover  116  is secured to the main support structure  114  by at least one fastener  118 . 
     The displacer housing  112  preferably supports at least one bearing block  120 , which in turn preferably supports a linkage shaft  122 . The linkage shaft  122  provides a mounting portion  124  for use in mounting a level adjustment bar  126 , which communicates with a transfer linkage  128 . During the discussion of  FIG. 3 , a response of the level adjustment bar  126  and transfer linkage  128  to a primary control input, such as the level of a fluid within a vessel, will be disclosed in greater detail. 
       FIG. 2  further shows the cartridge housing  110  confines an invertible pilot cartridge  130  (also referred to herein as cartridge  130 ). The cartridge  130  provides a first thrust pin  132 , which includes with a first pilot activation feature  134 ; and a second thrust pin  136  (see  FIG. 4 ), which includes a second pilot activation feature  138  (see  FIG. 4 ). The structure of the first thrust pin  132  differs from the second thrust pin  136  in that the first thrust pin  132  preferably provides a threaded aperture provided for interaction with a span control adjustment mechanism  140 . An important feature in a preferred embodiment of the span control adjustment mechanism  140  is an inclusion of an exhaust port  142 . 
     The controller  100  illustrated in  FIG. 2  shows the first thrust pin  132  is adjacent the detachable cover  116 , and the transfer linkage  128  communicating with the second thrust pin  136 . In this configuration, the cartridge  130  operates in a direct operating mode. As will be disclosed in greater detail during the discussion of  FIGS. 4-9 , the cartridge is designed to be symmetric about a fluid inlet access aperture  186  (see  FIG. 5 ) of the cartridge housing  110 . This symmetry of design facilitates mounting the second thrust pin of the cartridge  130  adjacent the detachable cover  116 , and attaching the transfer linkage  128  to the first thrust pin  132  to operate the cartridge  130  in an indirect operating mode. 
       FIG. 3  shows the base plate  108  provides a mounting block  144  for attachment of the cartridge housing  110  to the base plate  108 , the displacer housing  112  extends through the back of the base plate  108 , and is secured to the base plate  108  by an attachment flange  146  provided by the base plate  108 . 
     The displacer housing  112  provides access to the linkage shaft  122  for a displacer arm  148 . The level adjustment bar  126  is secured to the linkage shaft  122  by fasteners  150 . A distal end of the displacer arm  148  is attached to the linkage shaft  122  (not separately shown), and a proximal end  152  of the displacer arm  148  is secured to a swivel mechanism  154  that further connects with a displacer  156 . In response to an interaction of the displacer  156  (also referred to herein as float  156 ) with a rising fluid level the float  156  rises, which causes the displacer arm  148  to rise thereby imparting counter clockwise rotation on the linkage shaft  122 . 
     In response to be counter clockwise rotation of the linkage shaft  122 , the level adjustment bar  126  rotates in a counter clockwise direction causing the transfer linkage  128  to impart a downward force on the second thrust pin  136 . The downward force imparted on the second thrust pin  136  causes a generation of a control signal by the cartridge  130 . As illustrated, the controller  100  is configured with the cartridge  130  positioned for operation in the direct acting mode. However, when configured for operation in the indirect operating mode, the cartridge  130  generates a control signal in response to a lowering of the float  156 , typically caused by a lowering of a fluid interacting with the float  156 . 
       FIG. 3  further shows the base plate  108  provides support for a threaded shaft  158 , which accommodates the level adjustment bar  126 , a counterbalance compression spring  160 , and a counterbalance adjustment knob  162 . The counterbalance adjustment knob  162  is preferably provided with a threaded aperture  164  (see  FIG. 2 ), for interaction with the threaded shaft  158 . A clockwise rotation of the counterbalance adjustment knob  162  causes a counter clockwise rotation of the linkage shaft  122 , thereby raising the displacer  156 . A counter clockwise rotation of the counterbalance adjustment knob  162  causes a clockwise rotation of the linkage shaft  122 , thereby lowering the displacer  156 . Having an advantage of being able to adjust the vertical position of the displacer  156  relative to the displacer housing  112 , will become more clear during a disclosure of preferred embodiments of methods used for setting up the controller  100 . 
     In a preferred embodiment shown by  FIG. 4 , the invertible pilot cartridge  130  includes main cartridge body  165 , which support a plurality of seals that include o-rings  166  and a pair of diaphragms  168 . Preferably, a first of the pair of diaphragms  168  supports the first thrust pin  132 , and the second of the pair of thrust pins  136 . The first and second thrust pins  132 ,  136  are connected by spacers  170 , which serve to transfer fluid between upper and lower portions of a signal chamber  200  (see  FIG. 6 ). Preferably, a retention disc  172  is interposed between each of the pair of diaphragms  168  and each spacer  170 . In a preferred operating mode, the thrust pins  132 ,  136  move in unison causing a change in position of the span control adjustment mechanism  140  relative to the main cartridge body  165 , which controls the operation of a valve member  174  (also referred to herein as a peanut valve  174 ). 
     The main cartridge body  165  further provides a pilot spring retention member  176 , which in a preferred embodiment is a set screw. The pilot spring retention member  176  provides support to and confinement of a pilot spring  178  that urges a bottom valve face of the peanut valve  174  against a first valve seat  180 , provided by the main cartridge body  165 . A top valve face of the peanut valve  174  communicates with a second valve seat  182 , provided by the span control adjustment mechanism  140 , to regulate passage of pressurized fluid through the exhaust port  142 . Preferably, the pilot spring  178  is contained within a fluid input chamber  184  provided by the main cartridge body  165 . 
       FIG. 5  shows the main support structure  114  of the cartridge housing  110  provides the fluid inlet access aperture  186 , an output signal aperture  188 , a fluid supply pressure gauge aperture  190 , a fluid signal pressure gauge aperture  192 , a first thrust pin access aperture  194 , and a plurality of cover mounting apertures  196 . The detachable cover  116  provides a second thrust pin access aperture  198 . 
     When the controller  100  (of  FIG. 3 ) is configured for operation in an indirect operating mode, the cartridge  130  (of  FIG. 4 ) is mounted within the main support structure  114  of the cartridge housing  110  such that the first thrust pin  132  (of  FIG. 4 ) protrudes through the first thrust pin access aperture  194 . When the controller  100  is configured for operation in a direct operating mode, the cartridge  130  is mounted within the main support structure  114  of the cartridge housing  110  such that the second thrust pin  136  protrudes through the first thrust pin access aperture  194 . 
     It will be noted that regardless of whether the controller  100  is configured for use in a direct operating mode or an indirect operating mode, the fluid input chamber  184  (of  FIG. 4 ) (do to its central located within the main cartridge body  165  (of  FIG. 4 )) is consistently capable of being aligned for direct interaction and communication with the fluid inlet access aperture  186 . 
     For an enhance understanding of the present invention,  FIGS. 6 ,  7 ,  8 , and  9  should be viewed in concert. In a preferred embodiment, the present invention is a liquid level controller, such as controller  100 , which utilizes pressurized fluid, such as pressurized air, to operate a valve of a fluid storage vessel. When configured for operation in a direct operating mode, such as that shown by  FIGS. 6 and 7 , the controller is responsive to fluid within the fluid storage vessel reaching a maximum desired level. That is, when fluid in the storage vessel causes the float  156  (of  FIG. 3 ) to rise, the float  156  applies a rotational force to the level adjustment bar  126  (of  FIG. 3 ). The level adjustment bar  126  applies a downward force on the transfer linkage  128  (of  FIG. 3 ), which pulls the cartridge  130  from a position shown by  FIG. 6  to a position shown by  FIG. 7  (of note is the deformation of the diaphragms  168 ). When the cartridge is positioned as shown by  FIG. 7 , the bottom valve face of the peanut valve  174  recedes from the first valve seat  180 , which allows pressurized fluid to transfer from the fluid input chamber  184 , to the signal chamber  200  and out the output signal aperture  188 . 
     When the controller  100  is configured for operation in an indirect operating mode, such as that shown by  FIGS. 8 and 9 , the controller is responsive to fluid within the fluid storage vessel reaching a minimum desired level. That is, when fluid in the storage vessel causes the float  156  to fall, the float  156  applies a rotational force to the level adjustment bar  126 . The level adjustment bar  126  applies an upward force on the transfer linkage  128 , which pushes the cartridge  130  from a position shown by  FIG. 8  to a position shown by  FIG. 9  (of note is the deformation of the diaphragms  168 ). When the cartridge is positioned as shown by  FIG. 9 , the bottom valve face of the peanut valve  174  recedes from the first valve seat  180 , which allows pressurized fluid to transfer from the fluid input chamber  184 , to the signal chamber  200  and out the output signal aperture  188 . 
     In both cases, the controller responds by transmitting a signal, preferably in the form of pressurized fluid, to the valve controlling the fluid level within the fluid storage vessel. When operating in the direct mode, the pressurized fluid operates to close the valve supplying fluid to the fluid storage vessel, when the volume of the fluid within the storage vessel has reached a predetermined maximum level. When operating in the indirect mode, the pressurized fluid operates to open the valve supplying fluid to the fluid storage vessel when the volume of the fluid within the storage vessel has reached a predetermined minimum level. However, those skilled in the art will appreciate that directing pressurized fluid to valve&#39;s controlling fluid levels within fluid storage vessels is not the only method of controlling valves associated with fluid storage vessels. 
     It is contemplated that the scope of the present invention includes the response of the controller to the fluid level condition within the fluid storage vessel to be the transmission of electrical signals for use in controlling valves, such as solenoid valves. Accordingly, the selection of a pneumatically based control environment has been made to facilitate an enhanced understanding of the present invention and does not import any limitations on the present invention. 
     In a preferred embodiment, the main cartridge body  165  of the invertible pilot cartridge  130 , the span control adjustment mechanism  140 , and the first and second thrust pins  132 ,  136  are formed from aluminum. However, one skilled in the art will recognize, alternate materials such as brass, ceramic, and ridged hard-wearing polymers are among those found suitable for the present invention. 
     Preferably, and independent from the choice of materials used, the distance between the first valve seat  180  and the second valve seat  182  can be changed by rotating the span control adjustment mechanism  140 . Changing the distance between the first valve seat  180  and the second valve seat  182  changes the amount or span of movement of the float  156  (of  FIG. 3 ) needed to supply a control signal. The direction of rotation of the span control adjustment mechanism  140  determines whether the control signal, provided by the controller  100 , is a throttle type control signal, or a snap type control signal. 
     By turning the span control adjustment mechanism  140  to the right of a zero position, the cartridge operates in a throttle manner by providing a throttle type control signal, which allows for a more gradual change in the condition of the valve controlling the level of fluid within the storage vessel. By turning the span control adjustment mechanism  140  to the left of the zero position, the cartridge operates in a snap manner by providing a snap type control signal, which operates as an “on/off” signal. The further the span control adjustment mechanism  140  is positioned from the zero position, the larger the resulting span. 
     In a preferred embodiment, the controller  100  is calibrated for operation through use of the following procedure:
         1) Turn the span control adjustment mechanism  140  to a predetermined position mark  202  (see  FIG. 11 ), located on a top surface of the first thrust pin  132 , to set the span.   2) Adjust the liquid level within the storage vessel to the desired bottom switch point.   3) Increase the spring force by turning the counterbalance adjustment knob  162  (of  FIG. 2 ) clockwise until an output signal is provided by the controller  100 .   4) Decrease the spring force by turning the counterbalance adjustment knob  162  counter clockwise until the controller  100  halts the output signal.   5) The controller  100  is now calibrated to switch off at a bottom switch point and back on at a predetermined distance up from the bottom set-point. This predetermined distance is determined by the position of the span control adjustment mechanism  140 .       

     In an alternate preferred embodiment, the controller  100  is calibrated for operation through use of the following procedure:
         1) Turn the span control adjustment mechanism  140  to a predetermined position mark  202 , located on a top surface of the first thrust pin  132 , to set the span.   2) Adjust the liquid level in the storage vessel to the desired top switch point.   3) Increase the spring force by turning the counterbalance adjustment knob  162  clockwise until an output signal is provided by the controller  100 .   4) The controller  100  is now calibrated to switch on at the top switch point and off at a predetermined distance from the top set-point. This predetermined distance is determined by the position of the span control adjustment mechanism  140 .       

     In an alternative preferred embodiment, the controller  100  is calibrated for operation through use of the following procedure:
         1) Turn the span control adjustment mechanism  140  to a zero point  204  (see  FIG. 11 ), located on a top surface of the first thrust pin  132 .   2) Adjust the liquid level of the storage vessel to the desired top switch point.   3) Increase the spring force by turning the counterbalance adjustment knob  162  clockwise until an output signal is provided by the controller  100 .   4) Lower the level of the liquid in the storage vessel to the desired bottom level, which will cause the float  156  to be lowered, which thereby stops the output signal.   5) Turn the span control adjustment mechanism  140  away from the zero point  204  until the output signal is once again provided by the controller  100 .   6) Turn the adjustment knob towards the zero point until the output signal goes to zero.       

     Turning to  FIG. 12 , shown therein is a flow chart  300 , which depicts a method of operating a liquid level controller (such as  100 ). The method commences at start process step  302  and proceeds to process step  304  with a determination of an operating mode of an invertible pilot cartridge (such as  130 ) based on an orientation of the cartridge relative to a cartridge housing (such as  110 ). At process step  306 , a span control mechanism (such as  140 ) is set to a neutral position (such as  204 ) relative to the cartridge housing. At process step  308 , a float (such as  156 ) communicating with the cartridge and a fluid in a storage vessel is set to a neutral position relative to the cartridge housing. At process step  310 , the span control mechanism is adjusted to determine a signal response type of the cartridge, and the process concludes at end process step  312 . 
     In a preferred embodiment, the cartridge provides a first pilot activation feature (such as  134 ) of a first thrust pin (such as  132 ) that supports the span control mechanism, the cartridge housing includes a detachable cover (such as  116 ), and process step  304  includes at least a step of: orienting the first pilot activation feature adjacent the detachable cover to determine a direct operating mode of the cartridge; and securing the detachable cover to the cartridge housing in preparation for operating the controller in a direct operating mode. 
     In an alternate preferred embodiment, the cartridge provides the first pilot activation feature of the first thrust pin, which supports the span control mechanism, the cartridge housing includes the detachable cover, and process step  304  includes at least a step of: orienting said second pilot activation feature adjacent said detachable cover to determine an indirect operating mode of said cartridge; and securing said detachable cover to said cartridge housing in preparation for operating said liquid level controller in said indirect operating mode. 
     With respect to the above description, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. 
     It will be clear that the present invention is well adapted to attain the ends and advantages mentioned as well as those inherent therein. While presently preferred embodiments have been described for purposes of this disclosure, numerous changes may be made which will readily suggest themselves to those skilled in the art and which are encompassed by the appended claims.

Technology Classification (CPC): 8