Abstract:
A liquid collection and disposal assembly for collecting and disposing of drainage liquid, the liquid collection and disposal assembly disposable in a pit and having a basin assembly with a collection cavity, a pump suspended in the collection cavity and a level detector to detect drainage liquid levels in the collection cavity. A controller responds to the level detector to activate the pump at predetermined levels of the drainage liquid to evacuate the drainage liquid. A transparent basin cover is supported on top of a basin member, and an effluent discharge pipe is connected to the basin cover and to a liquid outlet port of the pump, thereby supporting the pump a predetermined distance above the bottom of the collection cavity. The pump has a water jacket through which the discharging effluent passes to cool the motor.

Description:
RELATED APPLICATIONS 
   This application is a continuation of non-provisional application Ser. No. 10/383,502 filed Mar. 7, 2003 now abandoned, entitled Automatic Sump Pump Assembly, which claims domestic priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 60/362,426 filed Mar. 7, 2002, entitled Submersible Automatic Pump. 

   FIELD OF THE INVENTION 
   The present invention relates generally to pump assemblies, and more particularly but not by way of limitation, to an automatic liquid collection and disposal assembly. 
   BACKGROUND OF THE INVENTION 
   Liquid disposal systems are generally used for the evacuation of drainage liquids, usually non-potable wastewater, in a large number of applications. Examples of such applications are found in residence and business building sites that are subject to drainage liquid collection, such as where shallow underground water levels cause wall seepage or where ground water runoff accumulates. Whatever the source of liquid collection, liquid disposal systems find application to pump the collected liquid, which is often non-potable water, to acceptable drainage lines, usually return sewer lines or storm water drainage systems. 
   Over the past several years, the overall design of pump assemblies for liquid disposal applications has experienced little change. Typically, liquid disposal assemblies can utilize upright, pedestal or fully submersible pumps. Operational pump control has relied upon some form of switch arrangement to detect the presence and level of liquid collected, such as, for example, the level of wastewater in a collection basin. Such switch arrangements have included float rod and ball switches for pedestal pumps; mercury float switches; mechanical float switches; and diaphragm pressure switches. These switch designs have changed little over the past several years and continue to incur well known deficiencies. 
   Float switch designs are prone to failure due to such factors as wear of mechanical parts; wedging debris entanglement that prevents effective operation; and operational disconnect or maladjustment. With each of these one can expect failure of the pump to maintain a desired liquid level in a collection vessel. 
   Diaphragm pressure switches rely on the differential movement of a diaphragm having one side exposed to atmospheric pressure and a head pressure on the other side. It is known that such switches can vary in reliability depending on the elevation of the installation, and the breather tubes commonly used to sense atmospheric pressure are often subject to obstruction. 
   Submersible pumps used in liquid disposal systems are susceptible to failure when the pumping elements become clogged or otherwise frozen. Wastewater reservoirs usually contain debris that is drawn into the pump, and poor pump performance and pump damage follows. 
   There is a continuing need for an automatic liquid collection and disposal assembly  100  that provides reliable detection of the level of collected liquid and automated control of the pump to reduce the potential for obstruction to the influent of collecting liquid, and which addresses other limitations associated with current prior art assemblies. 
   SUMMARY OF THE INVENTION 
   The present application provides an automatic pump assembly for evacuating drainage liquid collected in a pit, the automatic pump assembly having a basin assembly that forms a collection cavity and which is disposable in a pit. A pump is suspended in the collection cavity above the bottom of the basin, and a level detector serves to detect the level of the drainage liquid in the collection cavity. The pump has a liquid level indicator and a controller to activate the motor of the pump at predetermined levels of the drainage liquid. 
   The basin assembly has a basin member with an open top and a basin cover supported on the top of the basin member to substantially close the open top. An effluent discharge pipe is connected to the basin cover and to the liquid outlet port of the pump assembly to suspend the pump at a predetermined distance above the bottom of the basin member. 
   The advantages and features of the present invention will be apparent from the following description when read in conjunction with the accompanying drawings and appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a partially cutaway, side elevation view of an automatic pump assembly constructed in accordance with a preferred embodiment of the present invention. 
       FIG. 2  is a side elevation, cross-section view of the pump of the automatic pump assembly of  FIG. 1   
       FIG. 3  is a front elevation, cross-section view of the pump of  FIG. 2 . 
       FIG. 4  is an elevation view of the other side of the pump of  FIG. 2 . 
       FIG. 5  is a bottom plan view of the pump of  FIG. 2 . 
       FIG. 6  is an exploded view of the automatic pump assembly of  FIG. 1 . 
       FIG. 7  is a rear elevation view of the pump of  FIG. 2 . 
       FIG. 8  is a front view of the control module of the automatic pump assembly of  FIG. 1 . 
       FIG. 9  is a flowchart of the control steps for the pump system of  FIG. 1 . 
   

   DETAILED DESCRIPTION 
   Referring to  FIG. 1 , shown therein is an automatic liquid collection and disposal assembly  100  that has been installed in an earthen pit  102 . The automatic liquid collection and disposal assembly  100  includes a pump and motor assembly  104  with a liquid level detector  106  that are supported in a basin assembly  108  in the pit  102 . 
   The basin  108  provides a collection cavity  108 A for the accumulation of drainage liquids such as non-potable wastewater that enters a liquid entry port  109  that can be connected to a drainage conduit as required. 
   The automatic liquid collection and disposal assembly  100  has a control module  110  that is shown plugged into a nearby electrical outlet. 
   The construction and cooperative function of each of these components will be described with reference to  FIG. 1  and with reference to the several other included figures in which the same number designations will be used to designate the components. Numerous details of construction will be omitted where such will be known to persons skilled in the art and are not believed necessary for a full understanding of the present invention. 
   The basin assembly  108  includes a basin  112  and basin cover  114 . A plurality of fasteners (not separately designated) are used to fasten the basin cover  114  to the basin  112 . Preferably, the basin assembly  108  is installed so that top rim of the basin  112  is flush with the top rim of the pit  102 , and a concrete apron (not separately designated) poured around the top as shown. 
   The basin  112  is an open top vessel, and the basin cover  114  is preferably constructed of a transparent plastic such as polymethylmethacrylate or acrylonitrile-butadiene-styrene (ABS). The transparency of the basin cover  114  permits interior visual inspection of the basin  112  and the components of the automatic liquid collection and disposal assembly  100  disposed therein. 
   The dimensions and geometrical shape of the basin assembly  108  can be adapted to accommodate a variety of sizes and shapes of pits, such as illustrated by the pit  102 . For example, the basin assembly  108  can include additional capacity, structural ribbing for greater strength and integrated lifting handles. The basin assembly  108  is for a single pump, such as the pump and motor assembly  104 , and as discussed below, the basin assembly can be designed to accommodate more than one such pump and motor assembly. 
   The basin assembly  108  includes a mounting coupling  116  that is retained in an appropriately sized bore through the basin cover  114 . The mounting coupling  116  is connected to an effluent discharge pipe  118  that in turn is connected to the pump and motor assembly  104 . The effluent discharge pipe  118  has a first threaded end that makes up with a threaded connector output port of the pump and motor assembly  104 . The other end of the effluent discharge pipe  118  has an outer surface that is smooth for mechanical adhesive bonding to the coupling  116 . Thus, this arrangement of the coupling  116  and effluent discharge pipe  118  serve to support the pump and motor assembly  104  as shown. 
   The effluent discharge pipe  118  may also include an air relief vent hole (not shown). When the pump and motor assembly  104  is suspended from the basin cover  114  in the collection cavity  108 A, the vent hole will be located so as to spray water down at approximately a 45 degree angle from horizontal; this will serve to evacuate air trapped in the pump and motor assembly  104  or the effluent discharge pipe  118 . If employed, the vent hole should be located on the side of the effluent discharge pipe  118  away from the liquid level detector  106  to prevent false high water alarms potentially caused by the spray from the vent hole. 
   Preferably, the pump and motor assembly  104  is suspended by the effluent discharge pipe  118  and the coupling  116  from the basin cover  114  so that the bottom of the pump and motor assembly  104  is elevated a few inches above the bottom of the basin  112 . Elevating the bottom of the pump and motor assembly  104  reduces the susceptibility of the pump and motor assembly  104  to potential clogging by debris that can collect in the bottom of the basin  112  as drainage liquid accumulates. The suspension of the pump and motor assembly  104  in this manner also reduces operational noise that can occur by vibration between the pump and motor assembly  104  and the basin  112 . 
   As shown in  FIGS. 2 and 3 , the pump and motor assembly  104  has an inlet screen  120 , a motor  122 , a pump  123 , an outer shell or housing  124 , an inner shell or housing  126  and a support stand  128 . When pump and motor assembly  104  is suspended above the bottom of the basin  112 , the support stand  128  will not contact the basin  112 . However, when a particular application requires, the support stand  128  can be used to support the pump and motor assembly  104  on a supporting surface, such as the bottom of the basin  112 . To minimize the introduction of debris into the pump and motor assembly  104 , the support stand  128  has support legs dimensioned to elevate the bottom of the inlet screen  120  above the supporting surface should it be desirable in some applications to set the pump and motor assembly  104  on the bottom of the basin  108 . 
   The outer shell  124  is preferably constructed from a strong plastic, such as acrylonitrile-butadiene-styrene (ABS) to eliminate corrosion and prolong the life of the pump and motor assembly  104 . The inner shell  126 , which surrounds the motor  122 , is preferably constructed of a material having a high heat conductivity, such as an anodized, rigid aluminum, to dissipate heat from the motor  122 . Many of the other hardware parts of the pump and motor assembly  104  are preferably made of stainless steel to minimize corrosion. 
   The outer and inner shells  124 ,  126  form an annular space  129  that forms a liquid path that communicates with a liquid outlet port (not separately designated) to which the effluent discharge pipe  118  is connected for a center discharge of the pump  123 . The annular space  129  serves to direct effluent flow to the central liquid outlet port, and thus as an effluent discharge conduit for drainage liquid accumulated in, and pumped from, the pit  102 . The annular space  129  also serves as a water jacket surrounding the motor  122  so that the motor  122  is cooled by the pump effluent. That is, the drainage liquid pumped from the basin  112  passes between the outer and inner shells  124 ,  126  around all sides of the motor  122 , and because the motor  122  is water-cooled, the motor  122  does not require oil for lubrication or heat dissipation. 
   In a preferred embodiment, the motor  122  is a permanent split capacitor (PSC) motor contained within the fully submersible motor housing provided by the inner shell  126 . It is preferred that the motor  122  exhibit a low amperage draw during use. For example, the motor  122  can be a ⅓ horsepower, 60 Hertz, 3450 RPM, single phase, 115 volt electric motor that draws 4.5 FLA (full load amps) during use. The use of the low amp draw motor  122  provides energy efficient operation and low operational costs. 
   The motor  122  has a drive shaft  132  on which is mounted a pump impeller  130  that is supported in a pump volute chamber  133  having an inlet protected by the inlet screen  120 . The drive shaft  130  is preferably stainless steel and is supported for rotation by upper and lower ball bearings  134  that are shielded or sealed and permanently lubricated. The double ball bearings  134  provide for durable, efficient and quiet operation of the motor  122 . The double ball bearings  134  also absorb the axial and radial thrust loads placed on the motor  122 . The pump and motor assembly  104  also has two shaft seals  136  that prevent liquid entry into the motor  122 . As constructed, the motor  122  is sealed and watertight. 
   The impeller  132  preferably has a semi-open, recessed vortex design that includes pump out vanes on the backside to help eliminate clogging by foreign material entering the volute chamber  133 . The impeller  132  is molded around a brass insert (not numerically designated) and is balanced during manufacture. The brass insert is threaded, as is the end of the shaft  130 , and with a permanent adhesive is mounted on the end of the shaft  130 . 
   Turning to  FIG. 4 , the pump and motor assembly  104  has a power cord  138  and a control cord  140  electrically connected to the motor  122 . The power cord  138  connects the motor  122  to an appropriate power supply, such as a conventional 115 volt residential electrical system. The control cord  140  provides electrical communication between the liquid level detector  106  and the control module  110 , discussed below. Both cords  138 ,  140  are fully submersible and scalable to accommodate the conductivity requirements of a variety of applications. 
   Referring to  FIG. 5 , shown therein is the inlet screen  120  that prevents debris from being drawn into the volute chamber  133 . The inlet screen  120  is disposed on the bottom of the pump and motor assembly  104  and is preferably configured to prevent debris larger than about ⅛″ from entering the volute chamber  133  of the pump and motor assembly  104 . Also shown in  FIG. 5  is the bottom of the liquid level detector  106 . 
     FIG. 6  is an exploded view showing the interconnection of various components of the automatic liquid collection and disposal assembly  100 . As described above, the basin  112  supports the pump and motor assembly  104 , which is connected to the effluent discharge pipe  118 , which is in turn connected to the mounting coupling  116  of the basin cover  114 . A check valve  144  is connected to the mounting coupling  116  by a second discharge pipe  146 . Usually, this second discharge pipe  146  can be, for example, a 1½ inch NPT Schedule 80 pipe, smooth on both ends, with a connection on one end to the top of the mounting coupling  116  and the other end to the check valve  144 . 
   Preferably, the second discharge pipe  146  is connected to the mounting coupling  116  and check valve  144  through conventional means, such as by adhesive bonding. The check valve  144  can be a 1½ inch NPT, flapper-style check-valve, having a transparent housing that permits visual inspection of the valve operation. 
   The basin cover  114  preferably includes a two-cord grommet  148  through which the power and control cords  138 ,  140  pass for entry into the basin  112  for connection to the motor  122  and liquid level detector  106 , respectively. 
   In a typical application of the automatic liquid collection and disposal assembly  100  of the present invention, the pump and motor assembly  104  will be designed to produce 40 gallons per minute (GPM) at ten feet total dynamic head (TDH), with a maximum flow of 45 GPM at five feet TDH, and a maximum shutoff of thirty-two feet TDH. It will be understood that the size, scale and configuration of the pump and motor assembly  104  can be modified for various applications and that such modifications are within the scope of the present invention. 
   Referring now to  FIG. 7 , which provides the best view of the liquid level detector  106 , it will be noted that the liquid level detector  106  has a sensor housing  150  and three probes, an upper limit probe  152 , an intermediate limit probe  154  and a lower limit probe  156 , extending downwardly there from. The probes  152 ,  154 ,  156  are conventional capacitance probes that detect the presence of drainage liquid, usually non-potable water, at the lower end of each such probe. 
   The motor  122  and the liquid level detector  106  are connected to the control module  110  by the power cord  138  and the control cord  140 , respectively. The control module  110  is constructed in accordance with the teaching of U.S. Pat. No. 5,238,369 issued to Farr and entitled “Liquid Level Control With Capacitive Sensors,” which is incorporated by reference herein. Accordingly, it is believed not to be necessary to further describe the structure of the control module  110  as such will be readily understood by one skilled in the art of liquid level controllers. The operation of the control module  110 , and the cooperating functions of the limit probes  152 ,  154  and  156 , will be described below. 
   As shown, the upper limit probe  152  is the highest (measured from the base of the pump and motor assembly  104 ), the intermediate limit probe  154  is the next highest, and the lower limit probe  156  is the lowest. The probes  152 ,  154  and  156  are preferably made from a durable thermoplastic to resist corrosion, and each is sealed with epoxy above the capacitance plate mechanisms contained in the lower end to prevent moisture from reaching and condensing inside the sensor housing  150 . 
   The control module  110 , shown more clearly in  FIG. 8 , is configured to apply electrical power to the motor  122 , and thus to the pump  123 , in response to a signal from the liquid level detector  106  when the intermediate limit probe  154  detects that the level of drainage liquid in the basin  112  has accumulated to a depth that reaches the bottom of the intermediate limit probe  154 . Once the pump  123  is activated, the drainage liquid level will normally be lowered, and when the level of the drainage liquid in the basin  112  drops below the bottom of the lower limit probe  156 , the control module  110  powers down the motor  122  and pump  123 . 
   Should the level of drainage liquid continue to rise in the basin  112  to reach and be detected by the upper limit probe  152 , the control module  110  will turn on an alarm light  158  that will remain illuminated until the level is reduced to below the bottom of the upper limit probe  152 . 
   When the alarm light  158  is illuminated due to detection of a high drainage liquid level by the upper limit probe  152 , the control module  110  also turns on a high water alarm horn  160 . A toggling rocker-style silencer switch  162  is provided on the control module  110  to turn off the sound of the alarm horn  160 . That is, the audible warning sound of the alarm horn  160  can be silenced by toggling the rocker-style silencer switch  162  to its silence position. Even if the alarm horn  160  is thusly silenced, the alarm light  158  will remain illuminated on the automatic liquid collection and disposal assembly  100  until serviced, such as by a plumber to determine and remove the cause of the high level drainage liquid. Once the alarm situation has been remedied, the silencer switch  162  will be returned to its on position to place the alarm horn  160  back into service. 
   The control module  110  has a run light  164  that automatically turns on when the pump and motor assembly  104  is operational, and that automatically turns off when the pump and motor assembly  104  is not operating. The control module  110  should be sufficiently encased and sealed in an impact resistant plastic housing so as to be rated for indoor use, having a standard, three-prong 115 volt plug (not shown) for connection to a standard 115 volt household electrical outlet. 
   A flow chart depicting the operation of the automatic pump system  100  carried out according to preferred embodiments of the present invention is shown in  FIG. 9 . Beginning at step  200 , the control module  110  checks the mid-level probe  154  at step  202 , and if liquid is detected at step  204 , the liquid level is checked at the high level probe at step  206 . If the answer is no at step  206  (liquid is not detected at the high level probe), the motor  122 , and thus the pump  123 , is activated at step  208 , which also turns on the run light  164 . At step  210 , the query of whether the liquid level is below the low level probe is made, and if the answer is yes, the motor  122  is deactivated at step  212 . 
   If at step  204  the answer to the query of whether the liquid level is detected at the mid level probe  154  is no, the loop query returns to step  202 , and the motor  122  is not activated. At step  206 , if the query of whether the liquid level is detected by the high level probe  154  is yes, this means there is either a malfunction of the motor  122  (it did not turn on when activated) or the flow of incoming drainage liquid into the collection chamber is greater than the pump  123  can handle. Then, at step  206 , a yes answer causes an alarm signal to issue at step  214 , which turns on the alert light  158  at step  216  and turns on the audible alarm horn  160  at step  218 . 
   When an alarm condition has occurred as signaled by the alert light  158  at step  216  and the audible alarm horn at step  218 , it is expected that liquid collection and disposal assembly  100  will require service either by the owner or by a professional, technical service person. The system is configured so that the owner can easily turn off the audible alarm horn by toggling switch  162 , but the owner cannot turn off the alert light  158 , which will remain illuminated until the pump system  100  has received professional technical service. That is, the alert light  158  can be turned off externally and must be reset by one with the skill of entering the control module  110 . 
   The control module  110  makes the query of whether the service has received a technical service call by a designated professional person at step  220 , or whether it has received a home service by the owner at step  222 . If at step  220 , the answer is yes, the alert light  158  will be deactivated at step  224  and the audible alert horn turned off at step  226 . However, if no technical service (to remove and abate a failure condition) has been received, the answer at step  220  will be no, and both the alert light  158  and the audible alert horn  160  will stay on at steps  216  and  218 , respectively. 
   At step  222 , if the query by the control module as to whether home service has occurred is yes, the audible alert horn  160  will have been deactivated as at step  226 . If the answer at step  222  is no, both the alert light  158  and the audible alert horn  160  will continue to be activated as at steps  216  and  218 , respectively. 
   The control of the automatic pump system  100  by the control module  110  thus assures that the motor  122  is activated as necessary to keep the level of the drainage liquid in the collection chamber is maintained no higher than the mid level probe during normal operation. But should the level of drainage liquid in the collection chamber be detected at or above the high level probe, emergency conditions will be declared and both a visual and audible alarm will be activated until the pump system  100  receives attention by one capable of removing the cause of the failure. The owner can shut off the audible alert horn  160 , but cannot turn off the visual alert light  158 ; this assures that, even if the system has not received professional servicing, the continuously illuminated alert light  158  will inform the service person that a high level condition has occurred since the last professional service call. 
   In an alternate embodiment, the automatic liquid collection and disposal assembly  100  includes an auxiliary power system (APS), to provide continued pump availability during electrical power outages. The APS includes a battery in addition to the components included in the control module  110  described above. Preferably, the battery is a deep cycle, 12 volt battery commonly found in marine applications. When using the APS, the control module  110  is plugged directly into the APS, which in turn, is plugged into a standard 115 volt household electrical outlet. Should an electrical outage occur, the APS system provides backup power to the motor  122  from the battery. When online electrical power has been restored, the APS system switches back to the online supply. The APS system may also include a battery charger to ensure the readiness of the auxiliary battery. 
   In another preferred embodiment of the present invention, the pump system of the present invention will include additional pumps  123  for high-capacity installations. For such installations, multiple pumps  123 , discharge pipes  118 ,  146  with check valves  144 , mounting couplings  116 , cord grommets  148  and power and control cords  138 ,  140  will be provided as necessary. The multiple installation can be controlled using one or more level detectors  106  (for redundancy) and a control module  110  adapted to control the multiple pumps  123 . The multiple pump installation preferably will include duplex pump alternators to automatically alternate pump operation between cycles to extend operational lives of the pumps and to provide back-up in the event of pump failure. 
   It is clear that the present invention is well adapted to carry out its objectives and attain the ends and advantages mentioned above as well as those inherent therein. While presently preferred embodiments of the invention have been described in varying detail for purposes of disclosure, it will be understood that numerous changes may be made which will readily suggest themselves to those skilled in the art and which are encompassed within the spirit of the invention disclosed and as defined in the above text and in the accompanying drawings.