Patent Publication Number: US-2015059376-A1

Title: Programmable drain pump

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/871,798, filed Aug. 29, 2013, which is incorporated herein by reference. 
    
    
     FIELD 
     This disclosure relates to an evaporative cooler apparatus and, more particularly to a programmable drain pump for use with evaporative coolers in which a primary pump is used to supply water to an evaporative medium, and a secondary drain pump is used to drain the water pan of the evaporative cooler. 
     BACKGROUND 
     Evaporative cooler pumps have been known for many years. Typically, a single pump is used in an evaporative cooler to provide water for soaking an evaporative medium through which air is forced. The air is cooled evaporatively by giving up the latent heat of evaporation to the water in the evaporative medium. 
     An inherent problem with evaporative cooler pumps of the prior art is their limitation of pumping efficiently when the water level in the pan at the bottom of the evaporative cooler drops below a certain amount, which is typically an inch or so. As the water level decreases, there is cavitation caused by the pump design, namely the impeller of the pump, and the pump loses efficiency. Air is introduced into the stream of pumped water due to impeller cavitation, and the flow rate efficiency of the pump drops substantially. This is particularly important when the purpose of the pump is to evacuate the reservoir. 
     The evaporative cooler pump of certain embodiments includes an impeller design which greatly enhances the pumping flow rate efficiency by decreasing the cavitation and accordingly allowing the water level to drop substantially below that which is usable in the prior pumps, and still pumping efficiently without air bubbles in the pump water line. 
     A second feature of the pump apparatus of the present invention is the utilization of a secondary pump to periodically drain the evaporative cooler. 
     To decrease the dissolved solids (or salts) content of water used by evaporative coolers, a bleed system has been utilized by which a portion of the pumped water is continually bled off and drained out of the evaporative cooler. This requires the continual addition of new water to the evaporative cooler on a regular basis to replace the water that has bled off. The introduction of the fresh make-up water decreases the salt concentration content of the water in the cooler sump. 
     Since some of the water pumped to the evaporative medium drains down and returns to the sump, or bottom, of the evaporative cooler, that water includes the salts originally present in the water, and the buildup of salts in the cooler, and on the evaporative medium, causes a loss of efficiency of the evaporative medium and a buildup of the salts in the evaporative cooler housing itself The continuous bleed-off of the water requires the introduction of fresh water to help decrease the salinity concentration. On the other hand, the continuous bleed-off wastes a substantial amount of water. 
     A secondary pump, a drain pump, in the evaporative cooler apparatus of certain embodiments substantially decreases the waste of the water, such as heretofore bled off, by periodically draining the sump or bottom portion of the evaporative cooler housing, thus allowing for the introduction of fresh water on a periodic basis. This provides at least two advantages. The first advantage is the use of less water than the prior continual bleed systems, and a decrease in the salinity of the water due to the replenishment of the water on a regular basis. 
     A timer is used to actuate the drain pump on a regular basis. The salt or mineral buildup decreases, and the periodic changing of the water prevents a buildup or accumulation of stagnant water, and accordingly, there is a substantial decrease possibility of the breeding of mosquitoes in the evaporative cooler. 
     SUMMARY 
     The invention described and claimed herein comprises evaporative cooler apparatus in which a pair of evaporative cooler pumps is connected together. A primary, supply pump is used to provide water for the evaporative medium in the evaporative cooler. A secondary pump is used as a drain pump to periodically drain the water from the bottom of the evaporative cooler. The water is then replenished in the normal manner, such as by means of a float control valve. The pumps include impellers which allow the pumps to function efficiently in water depths as low as about a quarter of an inch or so without appreciable loss in flow rate. The impellers include vanes on both the bottom and the top of an impeller disk. The impeller design substantially increases the efficiency of the pumping process. A drain adapter is utilized to allow a drain pipe in the housing of the cooler apparatus to also be connected to the drain pump. The above-mentioned drain adapter also ensures the presence of an air gap to act as an anti-siphon protection. 
     In one aspect of the invention, the drain pump is a programmable drain pump having two modes of operation: a constant run mode wherein the drain pump continuously and indefinitely is in an on state and pumping water; and an alternating on/off, or intermittent run mode, whereby the motor turns on for a first programmed period of time and then turns off for a second programmed period of time, and then repeats the cycle. 
     Among the objects of certain embodiments of the present invention are the following:
     To provide a new and useful evaporative cooler apparatus;   To provide a new and useful evaporative cooler pump apparatus;   To provide a pair of pumps in an evaporative cooler;   To provide a new and useful evaporative cooler pump apparatus having a high efficiency impeller for pumping in relatively low water level;   To provide a new and useful drain adapter for an evaporative cooler;   To provide an evaporative cooler pump apparatus having a primary pump for supplying water to an evaporative medium and a secondary pump for draining the water in the evaporative cooler on a periodic basis; and   To provide a new and useful high efficiency evaporative cooler apparatus utilizing two pumps.   

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described in detail below with reference to the attached drawing figures, wherein: 
         FIG. 1  is a perspective view of an evaporative cooler such as may include a programmable drain pump of the present invention, showing the pump in its use environment; 
         FIG. 2  is a perspective view of a drain pump which may be a programmable drain pump of the present invention; 
         FIG. 3  is an exploded perspective view of a lower portion of the drain pump apparatus of  FIG. 2 ; 
         FIG. 4  is a side view in partial section of a lower portion of the drain pump apparatus of  FIG. 2 ; 
         FIG. 5  is a bottom plan view of an impeller portion of the drain pump apparatus of  FIG. 2 ; 
         FIG. 6  is a view in partial section taken generally along line  6 - 6  of the impeller of  FIG. 5 ; 
         FIG. 7  is a top plan view of the impeller of  FIG. 5 ; 
         FIG. 8  is a perspective view of a drain adapter portion of the apparatus of  FIG. 2 ; 
         FIG. 9  is a side view in partial section illustrating the drain adapter apparatus of  FIG. 8  in its use environment; 
         FIG. 10  is a top, right side perspective view of an embodiment of a programmable drain pump; 
         FIG. 11  is a top, front perspective view of the programmable drain pump of  FIG. 10 ; 
         FIG. 12  is a top, left side view showing the top panel of the programmable drain pump of  FIG. 10 ; 
         FIG. 13  is a top isometric view of an embodiment of the programmable drain pump, showing a pump control panel on a top surface of the programmable drain pump, as disclosed herein; 
         FIG. 14  is a cross section view of the programmable drain pump of  FIG. 13 , showing the internal components thereof, as disclosed herein; and 
         FIGS. 15A and 15B  are the two parts of a circuit diagram of the programmable circuit for an embodiment of the programmable drain pump as disclosed herein. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a perspective view of evaporative cooler apparatus  10 , which comprises the use environment of an evaporative cooler pump apparatus  70  and a programmable drain pump apparatus  100  of the present invention. The pumps  70  and  100  are shown disposed within an evaporative cooler housing  12 , and on a bottom wall  14  thereof. The housing  12  also includes a pair of side walls  16  and  20 , a back wall  24 , and a front wall, not shown, and a top wall  34 . The side walls  16  and  20  both include openings, and appropriate panels are disposed in the openings, and evaporative medium is in turn secured to panels in the openings. In  FIG. 1 , the evaporative medium  18  is shown disposed within the opening of the side wall  16 . An opening  26  is shown extending through the back wall  24 . The opening  26  may likewise include an appropriate panel for holding an evaporative medium. 
     Within the housing  12  is a blower housing  40 . A blower or fan disposed within the housing  40  provides the air flow into the interior of the housing  12  through the evaporative medium pads and into the structure to which the evaporative cooler apparatus  10  is secured. 
     An electric outlet  50  is shown secured to the blower housing  40 . A conductor  52  extends from the outlet  50  outwardly, as is well known and understood in the art. 
     A water input conduit  60  is shown extending to the side wall  16 . The conduit  60  is appropriately connected to a valve  62 . The valve  62  is controlled by a float  64 . As the water level within the bottom of the housing  12  decreases, the float  64  opens the valve  62  to replenish the water supply. Such is well known and understood by those of skill in this art. 
     Two pumps, a primary or supply pump  70 , and a secondary or drain pump  100 , are shown disposed on the bottom wall  14  of the housing  12 . The secondary or drain pump  100  is programmable as will be discussed in further detail hereinafter. A water conduit  72  extends from the supply pump  70  upwardly to a water distribution manifold or spider which in turn carries the water to the evaporative medium pads  18 . 
     The secondary or drain pump  100  is connected to a drain conduit  102 . 
     The conduit  102  extends and is connected to the drain adapter  200 , indicated at  204  in  FIG. 1 , at a first end thereof, which adapter  200  is then connected at a second opposite end to an overflow pipe  190  which is appropriately secured to and extends through the bottom wall  14  to allow the water pumped by the pump  100  to drain from the housing  12 . 
     An electrical cord  104  extends to a combination plug and receptacle  106 . The plug portion of the plug receptacle  106  is appropriately connected to the outlet  50 . The cord  74  and its plug  76  are in turn connected to the receptacle portion of the plug receptacle  106 . The two pumps  70  and  100  accordingly require only a single outlet or receptacle for their operation. 
     The supply pump  70  and the drain pump  100  are similar to each other. In one embodiment, the primary difference between them is a timer unit  180  in the drain pump  100  that may not be present in the supply pump. This will be discussed in detail below. However, in an alternate embodiment, the drain pump may be a programmable drain pump with increased programmable functionality. 
       FIG. 2  is a perspective view, partially broken away, of the drain pump  100  illustrating its electrical elements, including a timer  180 . The conduit  102  (see  FIGS. 1 and 9 ) extends from an outlet  116  of the drain pump  100  to a drain pipe  190  for draining water from the bottom of the cooler housing  12 , as discussed above and as will be discussed in detail below. 
     Details of the drain pump  100  are illustrated in  FIGS. 2 ,  3 , and  4 .  FIG. 3  is a bottom perspective view of the drain pump apparatus  100  particularly illustrating features of a pump impeller associated with both the supply pump  70  and the drain pump  100 .  FIG. 4  is a side view in partial section of the lower portion of the drain pump apparatus  100 , specifically illustrating the impeller portion of the pump. For the following discussion, reference will primarily be made to  FIGS. 2 ,  3 , and  4 . 
     The drain pump apparatus  100  includes a motor housing  110  in which is disposed an electrical motor  140 . Beneath the motor housing  110  is a shaft housing  112 . A motor shaft  142  extends from the motor  140  downwardly through the shaft housing  112  to an impeller  150 . Located on the motor shaft  142  partially down within the shaft housing  112  is a “slinger” (not shown). The slinger is a disc-shaped washer concentrically affixed about the motor shaft  142 , and located a short distance (e.g. 3-inches) above the impeller  150 , which location is also a short distance (e.g. 0.5-inches) above the normal water level in the sump/reservoir. The slinger is configured to rotate with, and form a liquid tight seal around the circumference of, the motor shaft so that any water that may migrate up the motor shaft  142  during operation of the pump is prevented from migrating past the slinger. When water reaches the slinger, it contacts the flat bottom surface of the slinger and is redirected outward along the bottom surface thereof, and toward the outer edge of the slinger. As the water moves toward the outer edge of the rotating slinger, due to the action of centrifugal force, the water picks up speed as it moves further to the outer edge of the slinger, where the migrating water is finally slung off of the slinger and motor shaft  142 . Beneath the shaft housing  112  is an impeller housing  114 . The shaft  142  extends into the impeller housing  114 . The impeller  150  is secured to the bottom of the shaft  142  within the housing  114 . 
     Above the motor  140 , and secured to the upper portion of the shaft  142 , is a fan  144 . The fan  144  provides a cooling flow of air for the motor  140  and the timer  180 . 
     The motor housing  110  is closed by a cap  126 . 
     At the bottom of the shaft housing  112  is a base  130 . The base  130  extends outwardly to provide a relatively sturdy base support for the motor housing  110 , the shaft housing  112 , and the various elements associated with the apparatus. Extending downwardly from the base  130  is a plurality of feet  132 . The feet  132  are spaced apart to allow water to flow between the feet and within the base  130  and to the impeller housing  114 . 
     The outlet  116  extends from the impeller housing  114 . The drain conduit  102  is connected to the outlet  116 . From the outlet  116 , the conduit  102  extends to a drain hose adapter  200 . The adapter  200  will be discussed in detail below in conjunction with  FIGS. 8 and 9 . 
     The impeller housing  114  comprises a generally relatively short cylinder in which is disposed the impeller  150 . The housing  114  includes an apertured top wall  118  and an apertured bottom plate  120 . Water flows into the impeller housing  114  through the apertured bottom plate  120 . 
     Details of the impeller  150  are shown in  FIGS. 5 ,  6 , and  7 , in addition to  FIGS. 3 and 4 . 
       FIG. 5  is a plan view of the bottom of the impeller  150 .  FIG. 6  is a view in partial section of the impeller  150  taken generally along line  6 - 6  of  FIG. 5 .  FIG. 7  is a plan view of the top of the impeller  150 . For the following discussion of the impeller  150 , reference will primarily be made to  FIGS. 5 ,  6 , and  7 , in addition to  FIGS. 3 and 4 . 
     The impeller  150  comprises a relatively thin and generally circular disk  152 . The disk  152  includes an outer periphery  154 . The disk  152  also includes a bottom surface  156  and a top surface  166 . 
     Disposed about the center of the disk  152 , and extending outwardly from the bottom surface of the disk  152  is a shaft boss  158 . A bore  160  extend through the shaft boss  158 . The bore  160  receives the shaft  142  of the motor  140 , as best shown in  FIGS. 3 and 4 . 
     Extending radially outwardly from the shaft boss  158  at the center of the disk  152  is a plurality of vanes  162 . As illustrated in  FIG. 5 , the vanes  162  are spaced apart equally a relatively few degrees, in comparison with contemporary pump impellers. Ten vanes  162  are shown in  FIG. 5  spaced apart equally from each other in the illustrated example. The distal tips or outer ends of the vanes  162  terminate inwardly from the outer periphery  154  of the disk  152 . 
     The configuration of the vanes  162  is best shown in  FIG. 6 . The “upper” or “outer” surface of each vane  162  is farthest from the bottom surface  156  adjacent to the boss  158  and are closest to the surface  156  remote from the boss  158 . In other words, the “height” of the vanes  162  tapers generally toward the surface  156  outwardly from the center portion of the disk  152 . 
     On the top surface  166  are shown four vanes  168 . The vanes  168  extend upwardly a relatively short distance from the top surface  166 , and they extend radially inwardly from the outer periphery  154  of the disk  152 . The vanes  168  terminate radially outwardly from the center portion of the disk  152 . Moreover, as best shown in  FIG. 7 , the configuration of the vanes  168  is generally rectangular. 
     The vanes  168  on the top  166  of the impeller  150  help to prevent water from being pushed up through the aperture in top wall  118  of the impeller housing  114 . 
     The disk  152  helps to prevent cavitation and accordingly allows the pump apparatus  100  to efficiently pump in water down to a depth of about a quarter of an inch Or so. 
     Returning again to  FIG. 2 , within the cap  126 , and disposed above the motor  140 , is the timer  180 . The timer  180  in the drain pump  100  in certain embodiments works in conjunction with the supply pump  70  so that after a predetermined cumulative time period of the on operation in the primary supply pump  70 , the timer  180  causes the motor  140  in the drain pump  100  to turn on, thus pumping the water from the bottom of the evaporative cooler housing  12  upwardly from the housing. The timer  180  in the drain pump  100  is preset so that it operates for a predetermined number of minutes before turning off. 
     For example, for every twelve hours of cumulative operation of the supply pump  70 , the timer  180  in the drain pump  100  will cause the drain pump  100  to operate for a short period of time, such as seven minutes. During the seven minute time period that the drain pump  100  operates, the water in the bottom of the evaporative cooler housing  12  is effectively drained down to a minimum amount in the bottom of the cooler apparatus  10 . At the same time, the demand for the water in the cooler apparatus  10  caused by the float  64  and the valve  62  causes fresh water to flow into the housing  12 . The fresh water replenishes the water supply that had been drained off by the drain pump  100 , and thus fresh water flows into the housing, substantially completely replacing the water in the housing  12  on a periodic basis. 
     It is apparent from the foregoing that when the water is pumped from the housing  12  by the drain pump apparatus  100 , the float  64  will cause fresh water to flow into the evaporative cooler housing  12 , thus diluting any old water that remains in the housing, such as any old water that has not been pumped out. The pump configuration ensures that most of the old water is pumped out and replaced by fresh water that is brought into the housing  12 . 
       FIG. 8  is a perspective side view of a drain adapter  200  useable with the drain pump  100  and the evaporative cooler apparatus  10  and particularly with the bottom  14  of the housing  12 .  FIG. 9  is a side view in partial section showing the adapter  200  secured to the overflow and drain pipe  190  and to the conduit  102 . For the following discussion, reference will primarily be made to  FIGS. 1 ,  8 , and  9 . 
     As indicated above, the overflow and drain pipe  190  is appropriately secured to and extends through the bottom  14  of the housing  12 . In prior art evaporative coolers, an overflow pipe serves as a safety feature for draining overflow water out of a cooler housing. In the apparatus of the present invention, the pipe  190  also serves as a drain pipe when the drain pump  100  is “on” for draining the housing  12 . 
     To allow both functions to be accomplished by the pipe  190 , the drain adapter  200  is used to connect the conduit  102  to the pipe  190 . The adapter  200  is “open” so that overflow water may drain through the pipe  190 . This opening also acts as an air gap providing an anti-siphon safety function. Water pumped through the conduit  102  flows downwardly along the adapter  200  to the pipe  190 . 
     The adapter  200  comprises an elongated “X” configured or cross-shaped element, with outwardly extending tabs  204  centrally located along the length of the element. The element  200  includes four elongated arms. Phrased in another manner, two arm portions preferably bisect each other at right angles, defining a four armed element. The arms extend outwardly from a central longitudinal axis of the adapter. 
     The width or effective diameter of the element  200  above and below the tabs  204  is essentially the same as the inner diameter of the drain pipe  190  and as the inner diameter of the conduit  102 . As shown in  FIG. 9 , the inner diameters of the pipe  190  and the conduit  102  are substantially the same. 
     The tabs  204  extend outwardly from the arm of the element  200 . The outwardly extending tabs  204  have a greater width or diameter, which width or diameter is preferably at least the same as the outer diameter of the pipe  190  to allow the adapter  200  to be comfortably disposed in and on the pipe  190 . 
     The “height” of the tabs  204  is sufficient to allow overflow water to flow into the pipe  190  between a top rim  192  of the pipe  190  and the bottom of the conduit  102  without problems of air flow or surface tension. Overflow water from the bottom of the housing  12  flows into the pipe  190  between the outwardly extending tabs  204  and the arms of the adapter element  200 . The tabs  204  are simply extensions of the aims which comprise the element  200 . 
     The tabs  204  essentially divide the arms of the adapter  200  into two portions, an upper portion  202  and a lower portion  206 . 
     As shown in  FIG. 9 , the bottoms of the tabs  204  are disposed on the top rim  192  of the pipe  190 . The upper arm portion  202  of the adapter  200  extends upwardly into the conduit  102 , and the bottom arm portion  206  extends downwardly into the pipe  190  from the tabs  204 . 
     An alternate embodiment of the adapter  200  is also illustrated in  FIG. 8 . In dash dot line is shown an arm  210 . The use of the arm  210 , with two of the four arms shown for the apparatus  200 , comprises a three armed adapter. Preferably, the arms of the adapters are spaced apart from each other equal arcuate distances. The arms of the three armed embodiment are disposed apart an equal arcuate distance, providing a one hundred twenty degree separation, as opposed to a ninety degree separation for the arms of the four armed adapter  200 . 
     In the three armed adapter, each arm has the same configuration as the arms illustrated for the four armed adapter  200 , with tabs extending outwardly from the arms to be disposed on the top rim of the drain or overflow pipe. The three arms extend outwardly from a central longitudinal axis. 
     The evaporative cooler apparatus  10  shown in  FIG. 1  is illustrated as being generally rectangular or square, but it will be understood that other configurations, such as round, may also be used. 
     While the principles of the invention have been made clear in illustrative embodiments, there will be immediately obvious to those skilled in the art many modifications of structure, arrangement, proportions, the elements, materials, and components used in the practice of the invention, and otherwise, which are particularly adapted to specific environments and operative requirements without departing from those principles. The appended claims are intended to cover and embrace any and all such modifications, within the limits only of the true spirit and scope of the invention. 
     As previously disclosed above herein, in one embodiment the drain pump  100  includes a timer, such as a mechanical timer, that turns the motor of the drain pump  100  on after a predetermined permanently fixed length of cumulative run-time of the supply pump  70  (e.g. every twenty-four hours). However, referring to  FIGS. 10-15 , in an alternate embodiment the drain pump is a fully programmable drain pump  300 . In use, the programmable pump  300  typically operates in a cycle, or alternating periods when the pump motor  140  is in an “on” state, so as to pump water to the drain pipe  190 , and periods when the motor is in an “off” state, and no water is being pumped by the drain pump  300 . 
     The programmable drain pump  300  of this alternate embodiment comprises the same mechanical components as previously disclosed above for the drain pump  100 , but also further includes programmable control circuitry that includes a processor having programming configured to control the operation of the pump between the two alternating “on” and “off” states. Specifically, in one embodiment, the processor is configured to switch the pump between each of the two “on” and “off” states in an alternating manner for specified periods of time. The user specified input to the processor is in the form of setting a timer corresponding to each of the “on” and “off” states. A first timer is set for the “run time” of the motor, which specifies the length of time that the motor is to be operated in the “on” state, following the expiration of a specified period when the motor was previously in an “off” state. A second timer is set for the “clean frequency,” which specifies the length of time that the motor is to be turned to an “off” state between successive periods when the motor is “on.” The control circuitry allows a user to specify or input both the run time and the clean frequency and thereby control alternating operation of the programmable pump  300  between an “on” and an “off” state. 
     To permit the input of both the clean frequency and run time, the programmable drain pump  300  further includes a control panel  310  disposed in a wall of the pump housing, such as for example, the top surface of the cap  126  of the pump housing, for specifying the user selectable run time and clean frequency values (typically in increments of minutes or hours) for the pump  300 . 
     In one embodiment, the clean frequency may be inputted by selecting one length of time from four pre-defined discreet lengths of time, such as for example two hours, four hours, six hours, or eight hours of “off” time for the programmable pump  300 . The time period selected for the clean frequency will be the amount of time that the pump is turned “off” between successive periods when the pump is in an “on” state and pumping water to the drain pipe. While the clean frequency of the present exemplary embodiment is selectable from only four options (two hours, four hours, six hours, or eight hours of “off” time for the pump), in alternate embodiments, the programmable drain pump  300  may include more or less than four options for the clean frequency selection, and the actual time periods for the clean frequency may be the same or different than those previously disclosed herein without departing from the scope of the present disclosure. 
     In one embodiment, the run time, or length of time that the pump is “on,” may be inputted by selecting from one of two discreet pre-programmed periods of time, such as for example a period of 5-minutes or a period of 9-minutes. The time period selected for the run time will be the amount of time that the pump is turned “on” between successive periods when the pump is in an “off” state and no pumping is being performed. While the run time of the present exemplary embodiment is selectable between only two options (5-minutes and 9-minutes of “on” time for the pump), in alternate embodiments, the programmable drain pump  300  may include more or fewer than two options for the run time selection, and the actual time periods for the run time may be the same or different than those previously disclosed herein without departing from the scope of the present disclosure. 
     The run time may be selected by pressing a run time select button  320  in the control panel  310 , which will highlight the specific labeled run time that has been selected, by lighting a corresponding light, LED, or other such similar indicator  322  positioned adjacent the label  324  for the chosen run time on the control panel  310 . The illustrated example provides run time selections of 5 minutes and 9 minutes, although other run times may be provided and more or fewer run time options may be provided. 
     The clean frequency may be selected in a similar manner by pressing a clean frequency select button  330  in the control panel  310 . As the clean frequency selection button  330  is selected, respective clean frequency selections are indicated by indicator lights  332 , for example, which are identified by indicia  334  marked on the control panel  310 . Each press of either the run time select button  320  or the clean frequency select button  330  will toggle the indicator associated with the respective button from one highlighted run time, or clean frequency, selection option to the next un-highlighted selection option. Once the indicator corresponding to the desired run time or clean frequency is highlighted, the indicated run time or clean frequency is respectively selected in the processor of the programmable drain pump. 
     Referring to  FIG. 11 , as an example, if the run time selection button  320  is pressed until the indicator light  322  corresponding to the five minute run time is highlighting as indicated by the “5 Min.” indicia, and the clean frequency selection button  330  is pressed until the indicator light  336  is highlighted corresponding to the clean frequency time of “4 Hrs.”, then in operation, the programmable pump  300  will alternate between being in the “on” state for 5 minutes, during which time the pump  300  is pumping water to the drain pipe  200 , followed by 4 hours in the “off” state, where the pump is turned off and not pumping any water. The cycle then repeats indefinitely until the pump is reprogrammed or the cycle is interrupted. 
     Turning to  FIG. 12 , the programmable drain pump  300  also includes on the control panel  310  a constant on button  312  that may be selected by a user to keep the pump constantly on, such as during a cleaning or flushing operation. In addition, a test button  314  is provided to enable the user to test whether the programmable drain pump  300  is operational, for example, for the duration of the selected run time without having to wait for the clean frequency time to elapse. 
     The illustrated example permits user selection of either five minute or nine minute run times at intervals of two hours, four hours, six hours, or eight hours, as shown on the control panel  310 . Of course, other run time durations may be available in other embodiments and other clean frequency intervals may be provided as options for user selection. More or fewer options may be provided in alternative embodiments. 
     In still further alternate embodiments (not shown), either of the run time or clean frequency may be infinitely, or nearly infinitely, variable, and inputted by a user entering the desired run time or clean frequency into the control circuitry with a numeric keypad, or changing the run time or clean frequency with “up” or “down” buttons that respectively and incrementally or continuously increase or decrease the particular time periods. In such embodiments, a display or digital readout would show the numerical length of time or other indicator that has been input to the processor. For example, a desired run time of 17 minutes would be inputted to the programmable drain pump by either keying in “1” “7” on a keypad, or pushing the “up” or “down” buttons for the run time until the number 17 is displayed on the display or readout. The selected indicator may instead refer to a hardness of the water, humidity in the air, or other condition or characteristic. 
     The programmable drain pump  300  may include the “constant on” selection button  312  that, when depressed, instructs the processor of the programmable pump to leave the motor of the programmable pump in the “on” state for an indefinite period of time, continuously pumping water, until the button is again depressed. This mode of operation is the constant on mode, and is useful, for example, if the programmable drain pump  300  must be used as a supply pump to supply water to the evaporative media of the evaporative cooler in the event that the primary supply pump  70  breaks down. The evaporative cooler will then not need to be shut down completely while the user procures a replacement supply pump. A subsequent depressing of the “constant on” button  312  will cease the operation of the pump  300  in the “constant on” mode and return the pump to operating in an alternating “on”/“off” mode where it is used as a drain pump as disclosed above. 
     In one embodiment, such a programmable drain pump  300  as disclosed herein may be configured to only be operational and tracking the clean frequency and run time of the drain pump  300  while the evaporative cooler is generating cool air. This means that the drain pump  300  is only operational when the recirculation pump  70  is simultaneously turned “on” and actively pumping water to the evaporative medium of the evaporative cooler. Therefore, in such an embodiment, the processor of the programmable drain pump  300  is also only tracking the length(s) of time that the drain pump  300  is in either of the “on” or “off” states while the recirculation pump  70  is also in an “on” state and pumping water to the evaporative medium. The supply pump  70  and the drain pump  300  are connected to one another either directly or indirectly to permit detecting of the supply pump operation by the drain pump. 
     For example, if the clean frequency on the programmable drain pump  300  is set to 2-hours (i.e. meaning 2-hours will pass between the end of one cleaning cycle and the beginning of the next cleaning cycle), and the recirculating pump  70  shuts down after 1-hour, the processor of the drain pump  300  will track/log the first hour of the drain pump&#39;s  300  “off” time, but will detect through the connection to the supply pump that the supply pump is off and will track no additional time until the recirculating pump  70  is again turned back “on” and pumping water. Once the recirculating pump  70  is turned back on, the processor of the programmable drain pump  300  will resume tracking time for the cleaning frequency until a total of 2-hours of cumulative time has elapsed, per the selected clean frequency period, after which the programmable drain pump  300  will then be turned “on” so as to operate to pump water to the drain pipe for the selected run time. 
     In alternate embodiments, the programmable drain pump  300  may be configured to track “on” and “off” time for each of the respective run time and clean frequency of the drain pump independently from the operation of the recirculating pump  70  without departing from the scope of the present disclosure. 
     Furthermore, in addition, the processor of the programmable drain pump  300  may be configured to track different time periods than those disclosed herein, such as for example, the length of time between the beginning of one cleaning cycle and the beginning of the next cleaning cycle (as opposed to the length of time between the end of one cleaning cycle and the beginning of the next cleaning cycle), without departing from the scope of the present disclosure. 
     Accordingly, there is disclosed herein a programmable drain pump for use in a dual pump evaporative cooling system, wherein the drain pump includes programming to permit adjustment of the run time and clean frequency of the drain pump and provide automatic operation of the drain pump at the selected intervals. This permits a user to set up customized cleaning schedules for an evaporative cooler, depending on the specific environmental factors in which the evaporative cooling system will operate. In addition, the programmable drain pump as disclosed herein may be used as a recirculation pump to allow for continuous operation of the evaporative cooler in the event that the primary recirculation pump breaks down. Accordingly, no run time of the evaporative cooling system is lost while the broken primary recirculating pump is repaired or replaced. 
       FIG. 13  shows the programmable pump  300  with the user operable buttons on the control panel  310 . The programmable drain pump is configured to fit into the cooling apparatus. In  FIG. 14 , the pump has a printed circuit board  370  mounted within the pump housing. The printed circuit board  370  includes a processor and associated circuitry so as to be operable to perform the functions described herein. The user input to the programmable drain pump  300  is provided by controls, such as the button  312  that is mounted on an upper printed circuit board positioned beneath the control panel  310 . A rubber seal is provided over the button  312  to keep water out of the electronics. A lower rubber seal  372  is provided below the circuit board  370  to prevent water from encroaching on the electronics from below. As noted above, the programmable pump  300  has a motor  140  that drives the impeller  150  via the shaft  142  and has a fan  144  for cooling the motor  140 . 
       FIGS. 15A and 15B  show a circuit  380  according to certain embodiments. The circuit  380  includes power conversion circuitry  381  and rectifying and filtering circuitry  382 , switches  384  for user input of commands relating to continuous operation, run time selection, and clean interval time selection, and indicator LEDs  386  for continuous operation, 2 hour interval, 4 hour interval, 6 hour interval, 8 hour interval, 5 minute run time, and 9 minute run time. A microcontroller processor chip HR6P60HL is connected in the circuit for automated operation of the motor based on the user selection via the switches  384 . A memory chip, such as a 24C04 chip, is connected to store the user settings. A test switch  388  is provided to test the operation of the drain pump. The illustrated circuit is but one example of a programmable circuit for operating the programmable drain pump. 
     Although other modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art.