Abstract:
An apparatus and methods of using the apparatus are disclosed. Preferably, the apparatus includes at least a fluid level detection portion communicating with a fulcrum that provides at least a first lobe and a second lobe, and a control portion responsive to the first lobe when the apparatus is operated in a first operating mode and responsive to the second lobe when the apparatus is operated in a second operating mode. The apparatus preferably further includes a counterbalance mechanism linked to the fluid level detection device, wherein the apparatus operates in the first mode when a first balance force is applied by the counterbalance mechanism to the fluid level detection device, and further operates in the second mode when a second balance force is applied by the counterbalance mechanism to the fluid level detection device.

Description:
FIELD OF THE INVENTION 
   This invention relates to fluid level monitoring devices, and in particular, but not by way of limitation, to liquid level controllers providing an ability to operate in either a direct or an indirect liquid level detection mode. 
   BACKGROUND 
   The present invention relates to an improved liquid level controller. Frequently, process intensive industries utilize process valves, which are operated by means of a pneumatic or electrical control signal, for the control of process fluids. The pneumatic control for such valves typically includes a pilot valve, whose function is to send an output signal pressure to the pneumatic controller, which either opens or closes the process valve. In the typical prior art system, the control of liquid levels in vessels has long been accomplished through use of a float whose motion or buoyancy force is transmitted to a pneumatic or electric controller which is connected to a process valve for opening and closing flow of liquid from the vessel. 
   In a typical operating environment, pneumatic pressure supplied to the pilot valve is used to facilitate operational control of process valves. When the liquid level in the vessel is within the desired limit, the pneumatic pressure is withheld from a discharge port, which is used to signal activation or deactivation of a process valve. As liquid within a vessel rises or falls sufficiently to change the position of the float, the pilot valve is activated to permit transfer of the pneumatic pressure through the discharge port to control operation of a process valve. For example, selectively activating a discharge valve or inlet valve to raise or lower fluid in a vessel results from activation of the pilot valve. 
   Many of the prior art devices were difficult to reconfigure from a direct operating mode (rising level increases pilot valve output), to an indirect operating mode (falling level increases pilot valve output) and vice versa, often leading to an inventorying of both operational mode devices, while other prior art devices necessitate a positional change in components of the device used to transmit the buoyancy force of the float to the pilot valve. 
   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. 
   BRIEF SUMMARY OF THE INVENTION 
   In accordance with preferred embodiments, an apparatus includes at least a fluid level detection portion communicating with a fulcrum, which provides at least a first lobe and a second lobe, and a control portion. The control portion preferably responds to the first lobe when the apparatus is operated in a first operating mode, and responds to the second lobe when the apparatus is operated in a second operating mode. The apparatus preferably also includes, a counterbalance mechanism linked to the fluid level detection device, wherein the apparatus operates in the first mode when a first balance force is applied by the counterbalance mechanism to the fluid level detection device, and further operates in the second mode when a second balance force, separate and distinct from the first balance force is applied by the counterbalance mechanism to the fluid level detection device. 
   In a preferred embodiment, a method of using the apparatus in a direct operating mode preferably includes the steps of: adjusting a force adjustment knob to counterbalance a mass of a displacer of a fluid level detection device; adjusting a level of fluid in a vessel to just below a bottom portion of the displacer of the fluid level detection device; rotating a force adjustment knob in a first rotational direction until all compressive force is relieved from a compressive force delivery device acting on the force adjustment knob; and reading a measurement device to confirm presence of an output signal. 
   The preferred method of using the apparatus in the direct operating mode further includes the steps of: turning the force adjustment knob in a second rotational direction until a pilot thrust pin just deactivates a control switch, thereby halting the presence of the output signal; continue turning the force adjustment knob in the second direction until the pilot thrust pin just activates the control switch, thereby providing the presence of the output signal; re-rotating the force adjustment knob in the first rotational direction until the pilot thrust pin just deactivates the control switch, thereby halting the presence of the output signal; re-reading the measurement device to confirm the non-presence of the output signal; and raising the level of fluid in the vessel until the pilot thrust pin just activates the control switch, thereby providing the presence of the output signal. 
   In a preferred embodiment, a method of using the apparatus in an indirect operating mode preferably includes the steps of: adjusting a force adjustment knob to counterbalance a mass of a displacer of a fluid level detection device; altering a level of a liquid in a vessel to just submerge the displacer of the liquid level detection device; reading a measurement device to confirm presence of an output signal; rotating a force adjustment knob in a counterclockwise direction until a pilot thrust pin just deactivates a control switch, thereby halting the presence of the output signal; and re-reading the measurement device to confirm non-presence of the output signal. 
   The preferred method of using the apparatus in the indirect operating mode further includes the steps of: resuming rotation of the force adjustment knob in the counterclockwise direction until all compressive force is relieved from a compression spring acting on the force adjustment knob; re-reading the measurement device to confirm presence of an output signal; turning the force adjustment knob in a clockwise direction until the pilot thrust pin just deactivates the control switch, thereby providing the non-presence of the output signal; re-reading the measurement device to confirm the non-presence of the output signal; and lowering the level of the liquid until the pilot thrust pin just activates the control switch, thereby providing the presence of the output signal. 
   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 liquid level controller. 
       FIG. 2  shows a front elevational view of a double lobed fulcrum of the inventive liquid level controller of  FIG. 1 . 
       FIG. 3  is a right side elevational view of the double lobed fulcrum of the inventive liquid level controller of  FIG. 2 . 
       FIG. 4  is a left side elevational view of the double lobed fulcrum of the inventive liquid level controller of  FIG. 2 . 
       FIG. 5  is a partial cutaway, right side elevational view of the inventive liquid level controller of  FIG. 1 . 
       FIG. 6  shows a partial cutaway, rear elevational view of the inventive liquid level controller of  FIG. 1 . 
       FIG. 7  illustrates a flow diagram of the method of using the inventive liquid level controller of  FIG. 1 , in a direct operating mode. 
       FIG. 8  illustrates a flow diagram of the method of using the inventive liquid level controller of  FIG. 1 , in an indirect operating mode. 
   

   DETAILED DESCRIPTION 
   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 apparatus  100 , which preferably includes at least a mounting plate  102 , a control portion  104  secured to the mounting plate  102 , and a torque bar  106 , that interacts with a control switch  108 , of the control portion  104  to, provide a control signal output. In a preferred embodiment the control switch  108  is a pneumatic switch, the control signal output is a pneumatic signal, provided at a predetermined pressure, and the torque bar  106  acts on a pilot thrust pin  110  to activate the control switch  108 . 
   Turning to  FIG. 2 , the innovative fluid level controller apparatus  100 , further preferably includes a level adjustment housing  112 , that supports a level detection portion  114 , which includes a displacer  115 , (which is preferably a float device), secured to a level translation shaft  116 , by a level response shaft  118 . The level response shaft  118  changes its vertical position relative to the level adjustment housing  112 , in response to changes in elevation of the displacer  115 . The displacer  115  responds to changes in the elevational level of a fluid supporting the displacer  115 . In a preferred embodiment, the fluid supporting the displacer  115  is confined within a vessel. 
   The level translation shaft  116  is secured to the level adjustment housing  112  by a bearing member  120 . The bearing member  120  facilitates rotation of the level translation shaft  116  about a center of access  122  of the level translation shaft  116 . The level translation shaft  116 , translates the vertical motion of the level response shaft  118  into rotational motion for use by a level adjustment arm  124 . The rotational motion of the level translation shaft  116  is used to create a vertical displacement of a distal end  126  of the level adjustment arm  124 . 
   Returning to  FIG. 1 , in addition to the level adjustment arm  124  (of  FIG. 2 ), a second level adjustment arm  128  is secured to the level translation shaft  116  (of  FIG. 2 ), and moves in concert with the level adjustment arm  124  in response to the rotational motion of the level translation shaft  116 . A fulcrum bar  130  is disposed between and held in place by the level adjustment arms  124 ,  128 , and supports a fulcrum  132 . 
   The fulcrum  132  includes a first lobe  134 , a second lobe  136 , and a fastening means  138  used to secure their position of the fulcrum  132  relative to the fulcrum bar  130 . In a preferred embodiment, the fastening means constitutes a thumb screw, but could easily be an allen head screw, machines screw, rivet, pin, or other forms of fastening means. Preferably, the material used for the fulcrum bar  130  is a rigid polymer, such as PVC, but could easily be formed from other materials such as metal, fiberglass, or composites. 
   In a preferred embodiment, the first lobe  134  acts on the torque bar  106  in response to a rising level of fluid supporting the displacer  115  (of  FIG. 2 ), by causing a clockwise rotation of the torque bar  106  about a pivot pin  140 . The pivot pin  140  is attached to the level adjustment housing  112  and supports the torque bar  106  a predetermined distance from the control portion  104 . The clockwise rotation of the torque bar  106  interacts with the pilot thrust pin  110 , which causes the control portion  104  to generate and output a signal, signifying a rise in the level of the fluid acting on the displacer  115  has reached a predetermined elevational height. 
   In a preferred embodiment, the control portion  104  includes the control switch  108 , that is preferably a pneumatic control switch  108 , which is activated by the action of the pilot thrust pin  110 . The result of the activation of the pneumatic control switch  108  by the pilot thrust pin  110  is a transfer of pressurized fluid from a pneumatic inlet port  142 , (shown with a quick disconnect fitting  143  protruding from the pneumatic inlet port  142 ) to a pneumatic output port (not shown separately), which can be measured by an output pressure gauge  144 . As will be appreciated by those skilled in the art, equivalent capabilities are available using electrical components, and can easily be substituted while remaining within the scope of the present inventive fluid level controller apparatus  100 . A pneumatic based system was chosen to enhance and heighten an understanding of the present inventive fluid level controller apparatus  100 , but does not serve to limit, nor is it intended to impose such a limitation on the present inventive fluid level controller apparatus  100 . 
   In an alternate preferred embodiment, the second lobe  136  acts on the torque bar  106  in response to a lowering in the level of a fluid supporting the displacer  115  (of  FIG. 2 ), by causing a counterclockwise rotation of the torque bar  106  about the pivot pin  140 . The counterclockwise rotation of the torque bar  106  interacts with the pilot thrust pin  110 , which causes the control portion  104  to generate and output a signal signifying a lowering in the level of the fluid acting on the displacer  115  has reached a predetermined elevational height. It will be noted that, in a preferred embodiment, the control portion  104  is mounted to the mounting plate  102  by means of control support standoffs  145 , which are preferably sized to position the pilot thrust pin  110  in a predetermined relationship with the torque bar  106 . 
   Continuing with  FIG. 2 , it is noted that in a preferred embodiment, the innovative fluid level controller  100  further includes a counterbalance mechanism  146 . The counterbalance mechanism  146  has been found useful for “subtracting out” the mass of the level detection portion  114 , i.e., offsetting the mass of the displacer  115 , thereby allowing the displacer  115  to be more responsive to elevational changes experienced by a fluid supporting the displacer  115 . 
   In a preferred embodiment, the counterbalance mechanism  146  includes at least a force adjustment shaft  148  interacting with a force adjustment knob  150  to modulate a force development member  152 , which in a preferred embodiment is a compression spring  152 . Preferably, the compression spring  152  is interposed between the force adjustment knob  150  and a force transfer portion  154  of the second level adjustment arm  128  (of  FIG. 1 ). 
   Preferably, as the force developed by the compression spring  152  increases in response to an advancement of the force adjustment knob  150  along the force adjustment shaft  148  in the direction of the mounting plate  102  (of  FIG. 1 ), a rotational motion is imparted on the level translation shaft  116 . The rotational motion imparted on the level translation shaft  116  is translated into a vertical displacement of the level response shaft  118 , which effectively acts to partially counteract the gravitational pull experienced by the displacer  115 . Also preferably, the force imparted by the compression spring  152  on the force transfer portion  152  is just sufficient to bring the level response shaft  118  into a position parallel with the pivot pin  140 . 
     FIG. 3  shows that the level translation shaft  116  includes a shaft union  156 . The shaft union  156  provides a means for connecting the level response shaft  118  (of  FIG. 2 ) to the level translation shaft  116 . In a preferred embodiment, the shaft union  156  provides a threaded mounting aperture  158  that interfaces with corresponding threads provided by the level response shaft  118 . 
     FIGS. 4 ,  5 , and  6  are preferably viewed in concert with one another, and they are provided to enhance an understanding of the present invention by those skilled in the art.  FIG. 4  shows a fulcrum bar access aperture  160 , sized to accommodate the fastening means  138  (of  FIG. 1 ), and providing access to the fulcrum bar  130  (of  FIG. 1 ).  FIG. 5  shows a fulcrum mounting aperture  162  sized to provide a sliding interface between the fulcrum  132  and the fulcrum bar  130 .  FIG. 6  shows a vertical separation  164  between the first lobe  134  and the second lobe  136  is preferably sized to accommodate the torque bar  106  (of  FIG. 1 ) in sliding communication with the first and second lobes  134 ,  136 , when the torque bar  106  is in a neutral position. 
     FIG. 7  shows method steps of a process  200  of using an inventive liquid level controller (such as fluid level controller  100 ). The process commences at start process step  202  and continues at process step  204 . At process step  204 , a displacer (such as  115 ) of the liquid level controller is counterbalanced by adjusting a force adjustment knob (such as  150 ), of a counterbalance mechanism (such as  146 ). The force adjustment knob is adjusted to position a fulcrum (such as  132 ), of the liquid level controller, into a neutral position relative to a torque bar (such as  106 ), of the liquid level controller. At process step  206 , a level of fluid in a vessel is adjusted to just below a bottom portion of the displacer of the fluid level detection device. At process step  208 , the force adjustment knob is rotated in a first rotational direction until all compressive force is relieved from a compressive force delivery device (such as compression spring  152  acting on the force adjustment knob, and at process step  210 , a measurement device (such as pressure gauge  144 ) is read to confirm presence of an output signal. 
   Continuing with the process at process step  212 , the force adjustment knob is rotated in a second rotational direction until a pilot thrust pin (such as  110 ) just deactivates a control switch (such as  108 ), thereby halting the presence of the output signal. At process step  214 , the measurement device is re-read to confirm the non-presence of the output signal. At process step  216 , turning of the force adjustment knob in the second direction is continued until the pilot thrust pin just activates the control switch, thereby providing the presence of the output signal, which is confirmed by reading the measurement device at process step  218 . 
   At process step  220 , the force adjustment knob is re-rotating in the first rotational direction until the pilot thrust pin just deactivates the control switch, thereby halting the presence of the output signal. The presence of the output signal is confirmed at process step  222  by re-reading the measurement device. At process step  224 , the level of fluid in the vessel is raised until the pilot thrust pin just activates the control switch, thereby providing the presence of the output signal, and the process concludes at end process step  226 . 
     FIG. 8  shows method steps of an alternate process  300  of using an inventive liquid level controller (such as fluid level controller  100 ). The process commences at start process step  302  and continues at process step  304 . At process step  304 , a displacer (such as  115 ) of the liquid level controller is counterbalanced by adjusting a force adjustment knob (such as  150 ) of a counterbalance mechanism (such as  146 ). The force adjustment knob is adjusted to position a fulcrum (such as  132 ) of the liquid level controller into a neutral position relative to a torque bar (such as  106 ) of the liquid level controller. At process step  306 , a level of fluid in a vessel is adjusted to submerge the displacer of the fluid level detection device. 
   At process step  308  the force adjustment knob is rotated in the counterclockwise direction until all compressive force acting on the force adjustment knob is relieved from a compression spring (such as  152 ), which activates an output signal from a control switch (such as  108 ). At process step  310 , a measurement device (such as pressure gauge  144 ) is read to confirm presence of the output signal. 
   At process step  312 , the force adjustment knob is turned in a clockwise direction until a pilot thrust pin (such as  110 ) just deactivates the control switch, thereby providing the non-presence of the output signal. At process step  314 , the measurement device is re-read to confirm the non-presence of the output signal. At process step  316 , the level of the liquid is lowered until the pilot thrust pin just activates the control switch, thereby providing the presence of the output signal, and the process concludes at end process step  318 . 
   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.