Abstract:
A flow control device for the drain lines of a septic system interrupts the flow in the event the proximate water table rises to a level of over-saturation resulting in the effluent flow being directed to the remaining drain lines. Each drain line is provided with a control box having a float controlled inlet valve having an open position allowing flow to the drain line. When the drain line cannot handle the required flow rate or when the proximate water table rises, the float shifts the valve toward a closed position, thereby redirecting the flow to the remaining lines.

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 60/593,356 filed on Jan. 7, 2005 in the name of James Tyler and entitled “Septic System Flow Control Box”. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to drainage systems and, in particular, to a system for controlling the flow of effluent in septic drain lines. 
     BACKGROUND OF THE INVENTION 
     Septic systems for handling the effluent from structures terminate in buried fields of drain pipes for leaching the effluent into the ground. Notwithstanding careful installation, the elevations and pitches of the drain pipes vary, resulting in a lesser number of drain pipes preferentially handling the output. Under adverse conditions, the ground surrounding the active pipes can become saturated resulting in the effluent penetrating and contaminating the ground surface. Such conditions do not affect the operation of the septic system and may not be apparent to the structure users in order to undertake the necessary maintenance or repair. If normal drainage cannot be restored, a separate secondary system may be required. Also, during the course of structure occupancy, the effectiveness of the original septic system may be compromised for other reasons, such terrain modification, additional capacity demand through site or population expansion, and changes in regulatory requirements and the like. It is thus common to include plans for such secondary or even tertiary systems. Generally, when required the original system is bypassed and the secondary system utilized for the current demands, even though the primary system may retain limited functionality. Further, suitable supplemental drainage may be available only at site elevations higher than the structure discharge elevation, requiring a separate pressurized system with pumping capabilities for transferring the effluent to the raised drain field location. 
     It would thus be desirable to provide a comprehensive septic system that avoids the above mentioned problems occasioned by temporary or substantial impairment of the original system and to utilize the total available capacity of the overall installation. 
     SUMMARY OF THE INVENTION 
     The present invention provides a flow control device for the drain lines of a septic system that interrupts the effluent flow in the event the proximate water table rises to a level of over-saturation thereby directing the effluent flow to the remaining drain lines. Each drain line is provided with a control box having a float controlled inlet valve having an open position allowing flow to the drain line. When the drain line cannot handle the required flow rate or when the proximate water table rises, the float shifts the valve toward a closed position, thereby redirecting the flow to the remaining lines. Multiple drain fields may be coupled thereby utilizing the available capacity of all the installed fields, rather than conversion to a separate system. To assist in sensitive opening and closing, the inlet valve may be provided with a progressively opening and closing sliding valve. During opening, the sliding valve provides an initial pilot valve opening to relieve line pressure followed by main valve opening to provide volumetric flow. During closing, the pilot valve initially closes and the float in conjunction with inlet line pressure moves the valve to a pressure biased closed position. 
     Accordingly, it is an object of the invention to provide a control system for limiting the flow to a septic drain line under conditions of reduced capacity to avoid ground saturation or penetration. 
     A further object is to provide a control system for the drain fields in a septic system wherein effluent flow is routed to other drain lines in response to conditions denoting impaired capacity. 
     Another object is to provide a septic line drain system wherein supplemental capacity can be added without disabling the original installation. 
     Another object is to control box for septic drain fields wherein a float controlled valve assembly progressively opens and closes to regulate flow from the septic system to the drain lines. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages of the present invention will become apparent upon reading the following description taken in conjunction with the accompanying drawing in which: 
         FIG. 1  is a schematic diagram of a septic drain line control system according to an embodiment of the invention; 
         FIG. 2  in a vertical cross sectional view of the control box for the septic drain line control system of  FIG. 1  with the float valve in the open position; 
         FIG. 3  is an enlarged cross sectional view of the float valve of the control box of  FIG. 2  with the float valve in the closed position; 
         FIG. 4  is an end view of the distribution box of the control system; 
         FIG. 5  is a schematic diagram of a septic drain line control system according to another embodiment of the invention; 
         FIG. 6  in a schematic elevational view of the control system of  FIG. 5 ; 
         FIG. 7  is a cross sectional view of the control box of the control system of  FIG. 5  with the float valve in the closed position; 
         FIG. 8  is a fragmentary cross sectional view of the control box of the control system of  FIG. 5  with the float valve in the open position; 
         FIG. 9  is a cross sectional view of a control box in accordance with another embodiment of the invention with the float valve in the closed position; 
         FIG. 10  is a fragmentary cross sectional view of the control box of  FIG. 9  with the float valve in the open position; 
         FIG. 11  is a view taken along line  11 - 11  in  FIG. 10 ; 
         FIG. 12  is an enlarged fragmentary cross sectional view of the control box of  FIG. 9  with the float valve in the closed position; and 
         FIG. 13  is an enlarged fragmentary cross sectional view of the control box of  FIG. 9  with the float valve in the open position. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , there is shown an embodiment of septic drain line control system  10  having a septic system for handling effluent from a structure  12 . The effluent is serially routed from the structure  12  along line  14  to a septic tank  16 . After settling, the effluent is routed along line  18  to a distribution box  20 . From the distribution box  20 , the effluent is routed along main outlet line  22  to feed lines  24  in drain fields  26 . Branch lines  28  are connected in parallel with the respective feed lines  24 . 
     Each branch line  28 , and optionally the associated feed line  24 , is provided with a control box  30  for controlling effluent distribution to the branch line  28  in accordance with the prevailing proximate effluent water table. 
     Referring to  FIGS. 2 through 4 , the control box  30  is a rectangular hollow body having vertically spaced top and bottom walls,  32 ,  34  respectively, transversely spaced side walls  36 ,  38  and laterally spaced end walls  40 ,  42 , the inner surfaces of which define a fluid chamber  44 . 
     An inlet line  50  is disposed at the upper center end of end wall  40  and is fluidly connected with feed line  24 . A main outlet line  52  in disposed at the lower center end of end wall  42  and is fluidly connected with branch line  28 . A secondary line  54  is disposed at the upper center of the end wall  42  and terminated with a ground port for facilitating monitoring and inspection. A plurality of vertically extending weep holes  56  are formed in the box, preferably in the end wall  42 , or other locations on the walls. In installation, the control box  30  is disposed in a subterranean cavity of surrounding drain stones. In normal operation, the normal effluent table level  58  is adjacent or below the bottom wall  38  and the effluent in the cavity  44  drains freely through main outlet line  52  for distribution along the length of the branch line  28 . 
     A float control valve assembly  60  is disposed in the box inlet line  50 , as a subassembly or unitized assembly. The control valve assembly  60  includes a flow pipe  62 , and a float assembly  64 . The float assembly  64  includes a circular valve disc  66  rotatably supported in the flow pipe  62  by horizontal pivot shaft  68 . A float assembly  70  including a hollow float  72  is operatively connected by arm  74  to the valve disc  66  and shaft  68 . Under normal drainage conditions with the normal water table, the float  72  pivots downwardly until the arm  74  engages the end of the pipe  62  and the valve disc  66  is in the illustrated open position. 
     Referring to  FIG. 3 , when the water table rises indicative of reduced proximate drainage, the surrounding water flows through holes  56  gradually raising the water level in the cavity to a raised level  76  and moving the valve disc  66  to a closed position blocking the flow of effluent from the distribution tank to the controlled drain line(s). Further pivoting of the disc  66  is blocked by a stop  78  on the inner end of the pipe  62 . Sealing gaskets may be employed to further reduce leakage in the closed position. Thereafter, flow from the distribution tank will be preferentially routed to remaining open branch lines. If the water level recedes, the valve assembly will gradually open to resume distribution. In the event sufficient valves close, the effluent will back up to the control box in the line  24  associated with the affected field thereby closing the valve thereat and routing flow to the other field. If both fields are saturated, the effluent will backup through the distribution tank and septic tank and resultantly to the structure, whereat the lack of drainage will effectively signal the need for maintenance or other curative action. 
     During the course of structure occupancy, the effectiveness of the original septic system may be compromised for various reasons, such as reduction in percolation of the drain lines due to contamination, terrain modification, additional capacity demand through site or population expansion changes in regulatory requirements and the like. It is thus common to include plans for secondary or tertiary systems. Generally, when required the original system is bypassed and the secondary system utilized for the current demands, even though the primary system retains limited functionality. Further, suitable drainage may be available only at site elevations higher than the structure discharge elevation, requiring a separate pressurized system with pumping capabilities for transferring the effluent to the raised drain field location. 
     A further embodiment for effectively handling the foregoing contingencies is shown in  FIGS. 5 through 8 . Referring to  FIG. 5 , a septic line drain control system  100  having a septic system  102  for handling effluent from a structure  104  discharged on outlet line  106 . The septic system  102  includes a main tank  110  having an inlet connected to the outlet line  106  and an outlet connected to a main distribution line  112 . The main distribution line  112  is connected with a primary distribution box  114  for selectively routing settled effluent from the main tank  110  to an original or primary drain system  120 . If flow to the primary drain system is blocked or limited, the flow from the primary distribution box  114  is routed to a secondary distribution box  122  along connector line  124  for routing to a secondary drain system  126 . The main distribution line  112  includes a Tee fitting  128  upstream of the primary distribution box  126  for routing effluent under conditions described below along branch line  130  to a secondary septic tank  132  for the pressure assisted delivery of effluent to a tertiary drain system  134  including a tertiary distribution box  136 . 
     The primary drain system  120  includes drain fields  140 , each of which is fluidly connected to the primary distribution box  114  by a branch line  141  including a control box  142 . The secondary drain system  126  includes drain fields  144 , each of which is connected to the secondary distribution box  122  by a control box  142 . The tertiary drain system  134  includes drain fields  146  connected to the tertiary distribution box  136  by a control box  142 . The distribution box  136  is connected with the tank  132  by a supply line  150  and a return line  152 . 
     Referring to  FIG. 6 , the main distribution line  112  flows downwardly below the ground  156  from the septic tank  110  to the Tee fitting  128  to the primary distribution box  114  with the indicative relative elevations as depicted. The box  114  comprises a thin walled container  166  covered by a lid  168  defining an interior cavity  170 . Three outlet branch lines  141  fluidly connect the cavity  170  with the respective drain fields  140 . The connector line  124  connects the primary distribution box  114  with the secondary distribution box  122 . The secondary distribution box  122  and the tertiary distribution box  136  are similar in construction, with the exception that the connector line connection is not utilized. Where the primary drain field  120  is the preferential drainage path, the branch lines  141  are lower than the connector line  124  whereby available flow is thereto as the liquid level in the cavity rises until routed along the connector line to the secondary field. If the preferences are reversed, the relative elevations are reversed. 
     As representatively shown in  FIGS. 7 and 8 , the outlet lines from the various distribution boxes are connected with a control box  142 . The control box  142  includes a generally thin wall base  180  having bottom and side walls defining an upwardly opening cavity  182  closed by a cover  184 . A control valve assembly  186  is mounted within the cavity  182  on a side wall and connected with a branch line  188  from a related distribution box. A feed line  190  is provided to route effluent to a connected field. Vertical weep holes  192  are provided on the side walls for reflecting proximate water table level in the cavity and for modulating the control valve assembly based thereon and exit flow. 
     The control valve assembly includes a T-shaped valve body  200  slidably supporting a slide valve member  202  including sealing rings  203 . The valve member  202  is actuated between an open position shown in  FIG. 8  and a closed position shown in  FIG. 7  by a float assembly  204 . The valve body  200  has a vertical bore  206  receiving the valve member  202  that is intersected by a center horizontal passage  208  connected with the line  188 . The float assembly  204  includes a float arm  210  pivotally connected at a center portion to a vertical bracket  212  at the top of the valve body  200  and pivotally connected at an inner end to an actuator rod  214  connected to a tab  216  on the top of the valve member  202 , and supporting a float  218  on an outer end whereby the float rises and lowers in response to the fluid level in the cavity  182  to shift the valve member  202  between the open position and the closed position thereby controlling the flow of effluent from the outlet line through the valve body passage into the cavity for routing through line  190  to the associated drain field. The float  214  engages to cover  184  to establish a stop position in the closed position. 
     Accordingly, based on local conditions at the control box  142 , the float rises in response to cavity liquid level throttling the valve closure limiting available flow to the connected drain field, and routing excess flow to the other fields or to the secondary distribution box, where flow is controlled in a like manner. In the event flow to both the primary and secondary distribution boxes is limited, the liquid level rises to the fitting  114  and excess flow is routed through line  130  to the secondary tank  128 . The secondary tank  128  includes a float activated pump  220  that directs fluid to the tertiary distribution box  136  along supply line  150  and to avoid pressurization thereat return excess fluid to the tank  128  along return line  152 . The flow from the box  136  to the control boxes  142  associated with the drain fields  146  of the tertiary system is similar to the operation at the primary and secondary system  120 ,  126 . 
     It will thus be appreciated that the systems are able to utilize the currently available capacities of the fields of the existing systems, and utilize the tertiary system only as required. 
     Referring to  FIGS. 9 and 10 , there is shown a further embodiment of the invention. Therein, a control box  300  for the septic drain system is provided with a progressive float valve assembly  302  for regulating the flow of fluid from an intake line  304  connected to a distribution box as described above. As described below, the float valve assembly includes a pilot valve function that initially opens to relieve the hydrostatic pressure in the intake line, and a main valve function that provides for volumetric flow into the control box and outward to the drain field. 
     The control box  300  includes a thin wall enclosure or housing  310  having a base  312  defining an upwardly opening cavity  314 , the upper end of which is sealed by a cover  316 . A wall of the housing includes an opening connected with an outline line  318  leading to the drain field. The intake line  304  is mounted on an end wall  320  of the base  312  at a mounting flange  322  that is suitably mechanically or adhesively attached to the inner surface of the end wall  320 . When the fluid in the cavity  314  is at level  324 , the valve assembly  302  is in the closed position as shown in  FIG. 9 . As the fluid level decreases, the valve assembly  302  is progressively opened to the open position shown in  FIG. 10 . 
     The valve assembly  302  is mounted in the cavity  314  at the inner end of the intake line  304 . The valve assembly  304  includes a valve body assembly  330  and a float arm assembly  332 . The float arm assembly  332  actuates a slide valve assembly  334  in response to changing fluid levels in the cavity  314 . 
     The float arm assembly  332  includes a pivot ring  336  mounted on the inner end of the valve assembly  302 . A float arm  338  is pivotally attached to an upper end of the pivot ring  336  at pivot connection  340 . The float arm  338  is generally Z-shaped and has a horizontal upper end  344  connected to the pivot ring  336  at the pivot connection  340 , a vertical middle section  346 , and a horizontal lower end  348  to which a float  350  is mounted at an upper surface and a counterweight  352  is attached at a lower surface. The middle arm  346  is connected to the slide valve assembly  334  at an actuating link  352 . 
     The valve assembly  302  includes a cylindrical valve body  360  having a stepped counterbore axially therethrough. The outer counterbore telescopically receives the inner end of the intake pipe  304 . The middle and inner bores slidably support the slide valve assembly  334 . 
     The slide valve assembly  334  includes an outer or main valve body  362  carrying a progressive valve assembly  364 . The valve body  362  includes a front cylindrical collar  370  and a rear cylindrical shaft  372  slidably supported in the inner bore of the valve body  360 . A sealing ring  374  is carried on the plug  372  adjacent the collar  370 . As shown in  FIG. 11 , the collar  370  includes a circumferential series of axial grooves  376 . In the open position shown in  FIGS. 10 and 12 , the sealing ring  374  is spaced from the base of the counterbore to permit flow through the grooves  376  in the direction of the arrows. In the closed position, the sealing ring  374  engages the base of the front counterbore to prevent flow. 
     As shown in  FIGS. 12 and 13 , the valve body  362  includes a stepped bore passage therethrough. The pilot valve assembly  364  includes a cylindrical plunger  380  supported in a rear counterbore  382  of the valve body. The link  352  is pivotally connected to the plunger  380  and the middle arm  346  of the lever arm assembly  332  as shown in  FIGS. 9 and 10 . The plunger  380  as shown in  FIG. 13  is spaced from the base of the counterbore at a lost motion connection in the closed position. As shown in  FIG. 12 , the plunger  380  engages the base of the counterbore after initial opening movement to shift the valve body  362  to the open position for providing volumetric flow. The plunger  380  of the pilot valve assembly  364  includes a threaded shaft  390  extending axially through the center passage. A pilot valve  392  is adjustably threadably connected to the shaft  390 . A sealing ring  394  having an inner diameter larger than the shaft  390  is retained in a groove at the base of the front counterbore. The pilot valve  392  includes a frustoconical tip  396  that engages the sealing ring  394  in the closed position of  FIG. 13 . In the open position as shown in  FIG. 12 , the tip  396  is spaced from the sealing ring  394  thereby allowing pilot flow in the direction of the arrows. The operation of the valves and the level  324  may be adjusted by axially shifting the pilot valve on the shaft  390 . The plunger  380  includes an outer cylindrical groove  398 . The valve body  362  includes radial ports  400  communicating with the groove  398  and allowing flow to the cavity  314  in the open position. An annular clearance is provided in the passage surrounding the shaft  390  and allows flow through ports  402  in the pilot valve assembly  364  in the open pilot position and the main valve position. 
     In operation, with the valve is in the open position wherein the float valve assembly  332  is in the lowered position shown of  FIG. 10  and both the main valve and the pilot valve are in the open position, as the fluid level rises, the float  350  rises shifting the link  352  and moving the pilot valve  392  to the closed position blocking flow through the pilot passage. As the in the fluid level further rises, the linkage is further shifted whereby the valve  392  shifts the valve body  362  to the closed position. When the liquid level in the cavity drops, the pilot valve  392  initially opens bleeding the pressure in the intake line and thereafter, the main valve opens to resume flow in the reservoir and outwardly to the drain field. 
     It will thus be appreciated that the control box provides a progressive valving function to provide sensitive and positive response to changing fluid levels. 
     Having thus described a presently preferred embodiment of the present invention, it will now be appreciated that the objects of the invention have been fully achieved, and it will be understood by those skilled in the art that many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the sprit and scope of the present invention. The disclosures and description herein are intended to be illustrative and are not in any sense limiting of the invention, which is defined solely in accordance with the following claim.