Automatic liquid collection and disposal assembly

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.

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 assembly100that 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.

DETAILED DESCRIPTION

Referring toFIG. 1, shown therein is an automatic liquid collection and disposal assembly100that has been installed in an earthen pit102. The automatic liquid collection and disposal assembly100includes a pump and motor assembly104with a liquid level detector106that are supported in a basin assembly108in the pit102.

The basin108provides a collection cavity108A for the accumulation of drainage liquids such as non-potable wastewater that enters a liquid entry port109that can be connected to a drainage conduit as required.

The automatic liquid collection and disposal assembly100has a control module110that is shown plugged into a nearby electrical outlet.

The construction and cooperative function of each of these components will be described with reference toFIG. 1and 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 assembly108includes a basin112and basin cover114. A plurality of fasteners (not separately designated) are used to fasten the basin cover114to the basin112. Preferably, the basin assembly108is installed so that top rim of the basin112is flush with the top rim of the pit102, and a concrete apron (not separately designated) poured around the top as shown.

The basin112is an open top vessel, and the basin cover114is preferably constructed of a transparent plastic such as polymethylmethacrylate or acrylonitrile-butadiene-styrene (ABS). The transparency of the basin cover114permits interior visual inspection of the basin112and the components of the automatic liquid collection and disposal assembly100disposed therein.

The dimensions and geometrical shape of the basin assembly108can be adapted to accommodate a variety of sizes and shapes of pits, such as illustrated by the pit102. For example, the basin assembly108can include additional capacity, structural ribbing for greater strength and integrated lifting handles. The basin assembly108is for a single pump, such as the pump and motor assembly104, and as discussed below, the basin assembly can be designed to accommodate more than one such pump and motor assembly.

The basin assembly108includes a mounting coupling116that is retained in an appropriately sized bore through the basin cover114. The mounting coupling116is connected to an effluent discharge pipe118that in turn is connected to the pump and motor assembly104. The effluent discharge pipe118has a first threaded end that makes up with a threaded connector output port of the pump and motor assembly104. The other end of the effluent discharge pipe118has an outer surface that is smooth for mechanical adhesive bonding to the coupling116. Thus, this arrangement of the coupling116and effluent discharge pipe118serve to support the pump and motor assembly104as shown.

The effluent discharge pipe118may also include an air relief vent hole (not shown). When the pump and motor assembly104is suspended from the basin cover114in the collection cavity108A, 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 assembly104or the effluent discharge pipe118. If employed, the vent hole should be located on the side of the effluent discharge pipe118away from the liquid level detector106to prevent false high water alarms potentially caused by the spray from the vent hole.

Preferably, the pump and motor assembly104is suspended by the effluent discharge pipe118and the coupling116from the basin cover114so that the bottom of the pump and motor assembly104is elevated a few inches above the bottom of the basin112. Elevating the bottom of the pump and motor assembly104reduces the susceptibility of the pump and motor assembly104to potential clogging by debris that can collect in the bottom of the basin112as drainage liquid accumulates. The suspension of the pump and motor assembly104in this manner also reduces operational noise that can occur by vibration between the pump and motor assembly104and the basin112.

As shown inFIGS. 2 and 3, the pump and motor assembly104has an inlet screen120, a motor122, a pump123, an outer shell or housing124, an inner shell or housing126and a support stand128. When pump and motor assembly104is suspended above the bottom of the basin112, the support stand128will not contact the basin112. However, when a particular application requires, the support stand128can be used to support the pump and motor assembly104on a supporting surface, such as the bottom of the basin112. To minimize the introduction of debris into the pump and motor assembly104, the support stand128has support legs dimensioned to elevate the bottom of the inlet screen120above the supporting surface should it be desirable in some applications to set the pump and motor assembly104on the bottom of the basin108.

The outer shell124is preferably constructed from a strong plastic, such as acrylonitrile-butadiene-styrene (ABS) to eliminate corrosion and prolong the life of the pump and motor assembly104. The inner shell126, which surrounds the motor122, is preferably constructed of a material having a high heat conductivity, such as an anodized, rigid aluminum, to dissipate heat from the motor122. Many of the other hardware parts of the pump and motor assembly104are preferably made of stainless steel to minimize corrosion.

The outer and inner shells124,126form an annular space129that forms a liquid path that communicates with a liquid outlet port (not separately designated) to which the effluent discharge pipe118is connected for a center discharge of the pump123. The annular space129serves 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 pit102. The annular space129also serves as a water jacket surrounding the motor122so that the motor122is cooled by the pump effluent. That is, the drainage liquid pumped from the basin112passes between the outer and inner shells124,126around all sides of the motor122, and because the motor122is water-cooled, the motor122does not require oil for lubrication or heat dissipation.

In a preferred embodiment, the motor122is a permanent split capacitor (PSC) motor contained within the fully submersible motor housing provided by the inner shell126. It is preferred that the motor122exhibit a low amperage draw during use. For example, the motor122can 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 motor122provides energy efficient operation and low operational costs.

The motor122has a drive shaft132on which is mounted a pump impeller130that is supported in a pump volute chamber133having an inlet protected by the inlet screen120. The drive shaft130is preferably stainless steel and is supported for rotation by upper and lower ball bearings134that are shielded or sealed and permanently lubricated. The double ball bearings134provide for durable, efficient and quiet operation of the motor122. The double ball bearings134also absorb the axial and radial thrust loads placed on the motor122. The pump and motor assembly104also has two shaft seals136that prevent liquid entry into the motor122. As constructed, the motor122is sealed and watertight.

The impeller132preferably 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 chamber133. The impeller132is molded around a brass insert (not numerically designated) and is balanced during manufacture. The brass insert is threaded, as is the end of the shaft130, and with a permanent adhesive is mounted on the end of the shaft130.

Turning toFIG. 4, the pump and motor assembly104has a power cord138and a control cord140electrically connected to the motor122. The power cord138connects the motor122to an appropriate power supply, such as a conventional 115 volt residential electrical system. The control cord140provides electrical communication between the liquid level detector106and the control module110, discussed below. Both cords138,140are fully submersible and scalable to accommodate the conductivity requirements of a variety of applications.

Referring toFIG. 5, shown therein is the inlet screen120that prevents debris from being drawn into the volute chamber133. The inlet screen120is disposed on the bottom of the pump and motor assembly104and is preferably configured to prevent debris larger than about ⅛″ from entering the volute chamber133of the pump and motor assembly104. Also shown inFIG. 5is the bottom of the liquid level detector106.

FIG. 6is an exploded view showing the interconnection of various components of the automatic liquid collection and disposal assembly100. As described above, the basin112supports the pump and motor assembly104, which is connected to the effluent discharge pipe118, which is in turn connected to the mounting coupling116of the basin cover114. A check valve144is connected to the mounting coupling116by a second discharge pipe146. Usually, this second discharge pipe146can 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 coupling116and the other end to the check valve144.

Preferably, the second discharge pipe146is connected to the mounting coupling116and check valve144through conventional means, such as by adhesive bonding. The check valve144can be a 1½ inch NPT, flapper-style check-valve, having a transparent housing that permits visual inspection of the valve operation.

The basin cover114preferably includes a two-cord grommet148through which the power and control cords138,140pass for entry into the basin112for connection to the motor122and liquid level detector106, respectively.

In a typical application of the automatic liquid collection and disposal assembly100of the present invention, the pump and motor assembly104will 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 assembly104can be modified for various applications and that such modifications are within the scope of the present invention.

Referring now toFIG. 7, which provides the best view of the liquid level detector106, it will be noted that the liquid level detector106has a sensor housing150and three probes, an upper limit probe152, an intermediate limit probe154and a lower limit probe156, extending downwardly there from. The probes152,154,156are conventional capacitance probes that detect the presence of drainage liquid, usually non-potable water, at the lower end of each such probe.

The motor122and the liquid level detector106are connected to the control module110by the power cord138and the control cord140, respectively. The control module110is 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 module110as such will be readily understood by one skilled in the art of liquid level controllers. The operation of the control module110, and the cooperating functions of the limit probes152,154and156, will be described below.

As shown, the upper limit probe152is the highest (measured from the base of the pump and motor assembly104), the intermediate limit probe154is the next highest, and the lower limit probe156is the lowest. The probes152,154and156are 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 housing150.

The control module110, shown more clearly inFIG. 8, is configured to apply electrical power to the motor122, and thus to the pump123, in response to a signal from the liquid level detector106when the intermediate limit probe154detects that the level of drainage liquid in the basin112has accumulated to a depth that reaches the bottom of the intermediate limit probe154. Once the pump123is activated, the drainage liquid level will normally be lowered, and when the level of the drainage liquid in the basin112drops below the bottom of the lower limit probe156, the control module110powers down the motor122and pump123.

Should the level of drainage liquid continue to rise in the basin112to reach and be detected by the upper limit probe152, the control module110will turn on an alarm light158that will remain illuminated until the level is reduced to below the bottom of the upper limit probe152.

When the alarm light158is illuminated due to detection of a high drainage liquid level by the upper limit probe152, the control module110also turns on a high water alarm horn160. A toggling rocker-style silencer switch162is provided on the control module110to turn off the sound of the alarm horn160. That is, the audible warning sound of the alarm horn160can be silenced by toggling the rocker-style silencer switch162to its silence position. Even if the alarm horn160is thusly silenced, the alarm light158will remain illuminated on the automatic liquid collection and disposal assembly100until 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 switch162will be returned to its on position to place the alarm horn160back into service.

The control module110has a run light164that automatically turns on when the pump and motor assembly104is operational, and that automatically turns off when the pump and motor assembly104is not operating. The control module110should 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 system100carried out according to preferred embodiments of the present invention is shown inFIG. 9. Beginning at step200, the control module110checks the mid-level probe154at step202, and if liquid is detected at step204, the liquid level is checked at the high level probe at step206. If the answer is no at step206(liquid is not detected at the high level probe), the motor122, and thus the pump123, is activated at step208, which also turns on the run light164. At step210, the query of whether the liquid level is below the low level probe is made, and if the answer is yes, the motor122is deactivated at step212.

If at step204the answer to the query of whether the liquid level is detected at the mid level probe154is no, the loop query returns to step202, and the motor122is not activated. At step206, if the query of whether the liquid level is detected by the high level probe154is yes, this means there is either a malfunction of the motor122(it did not turn on when activated) or the flow of incoming drainage liquid into the collection chamber is greater than the pump123can handle. Then, at step206, a yes answer causes an alarm signal to issue at step214, which turns on the alert light158at step216and turns on the audible alarm horn160at step218.

When an alarm condition has occurred as signaled by the alert light158at step216and the audible alarm horn at step218, it is expected that liquid collection and disposal assembly100will 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 switch162, but the owner cannot turn off the alert light158, which will remain illuminated until the pump system100has received professional technical service. That is, the alert light158can be turned off externally and must be reset by one with the skill of entering the control module110.

The control module110makes the query of whether the service has received a technical service call by a designated professional person at step220, or whether it has received a home service by the owner at step222. If at step220, the answer is yes, the alert light158will be deactivated at step224and the audible alert horn turned off at step226. However, if no technical service (to remove and abate a failure condition) has been received, the answer at step220will be no, and both the alert light158and the audible alert horn160will stay on at steps216and218, respectively.

At step222, if the query by the control module as to whether home service has occurred is yes, the audible alert horn160will have been deactivated as at step226. If the answer at step222is no, both the alert light158and the audible alert horn160will continue to be activated as at steps216and218, respectively.

The control of the automatic pump system100by the control module110thus assures that the motor122is 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 system100receives attention by one capable of removing the cause of the failure. The owner can shut off the audible alert horn160, but cannot turn off the visual alert light158; this assures that, even if the system has not received professional servicing, the continuously illuminated alert light158will 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 assembly100includes 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 module110described above. Preferably, the battery is a deep cycle, 12 volt battery commonly found in marine applications. When using the APS, the control module110is 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 motor122from 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 pumps123for high-capacity installations. For such installations, multiple pumps123, discharge pipes118,146with check valves144, mounting couplings116, cord grommets148and power and control cords138,140will be provided as necessary. The multiple installation can be controlled using one or more level detectors106(for redundancy) and a control module110adapted to control the multiple pumps123. 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.