Abstract:
The pulse pump is driven by an electric motor and gear reduction driving an eccentric rotor, which, in turn, oscillates a mechanism actuating a diaphragm to transfer fluid through one-way check valves. The pump may be used in a number of different applications, but is particularly useful in applying biodegradation material to consume grease and other biodegradable matter typically found in drainage systems of food processing facilities, converting such matter into carbon dioxide and water. The device includes a system for placing the mechanism in a neutral position when the pump is deactivated, to avoid causing the diaphragm to take a set toward either extreme of travel when parked for an extended time. One embodiment incorporates a multiple piece actuator assembly having a diaphragm sandwiched between components. Another embodiment uses a single piece actuator having a circumferential groove, with the diaphragm having a toroid configuration and attaching within the groove.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/272,559, filed Oct. 6, 2009. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to fluid transfer pumps. More specifically, the present invention is a reciprocating pulse pump driven by an eccentric rotor and incorporating an electronic system for neutralizing the position of the diaphragm when the pump is inoperative. 
         [0004]    2. Description of the Related Art 
         [0005]    Relatively small reciprocating pumps incorporating a flexible diaphragm and one-way check valves are used in a number of different fields and environments. In the food processing industry, e.g., restaurants, bakeries, canneries, and the like, processing activities result in the generation of byproducts such as grease, oil, flour, sugar, and other organic matter that tends to adhere to the inner surface of drain lines. As the accumulation increases, so does the potential for drain line blockage and resulting backup. 
         [0006]    One of the methods commonly used in such food processing facilities to alleviate the accumulation of organic matter is to use small pumps (generally peristaltic type) as part of an automated delivery system designed to deliver certain biodegradation fluids to a targeted area, which is typically the most active drain leading to the grease interceptor of the facility. The fluids used in these systems (usually water) often include one or more strains of bacteria along with other ingredients such as nutrients, neutralizers, etc., for the purpose of breaking down the grease and other biodegradable byproducts adhering to the inner surfaces of drain lines, into carbon dioxide and water. 
         [0007]    Another area of concern is the drink dispenser (often called the “beverage tower”) commonly found in various fast food, full service and other restaurants. The drain tube extending from this equipment to the drainage network beneath the floor can become blocked with sugar “snakes,” i.e., buildup, in a relatively short period of time and it can be difficult to eliminate such buildup within the relatively small drain tube passages. There are numerous examples of similar situations in which the injection of a biodegradation agent by means of an automated pump would be desirable for controlling and removing the accumulation of biodegradable matter. 
         [0008]    A number of pumps have been developed in the past. An example of such is found in French Patent Publication No. 2,485,108 published on Dec. 24, 1981. This reference shows (according to the drawings) a solenoid-actuated diaphragm pump with inlet and outlet one-way check valves. 
         [0009]    Thus a pulse pump solving the aforementioned problems is desired. 
       SUMMARY OF THE INVENTION 
       [0010]    The pulse pump comprises various embodiments differing in the configuration of the internal mechanism for operating the pump diaphragm and the diaphragm configuration as well. Each embodiment incorporates an electric drive motor controlled by a power switch (e.g., an “on-off” switch) through a programmable control module. The motor drives a gear reduction system, which in turn drives an output shaft. The shaft rotates an eccentric rotor that in turn oscillates or reciprocates a mechanism, which drives a diaphragm back and forth in a chamber. The chamber communicates with inlet and outlet ports or passages, each having a one-way check valve installed therein. An electronic system for neutralizing the position of the diaphragm during periods of pump inactivity is also provided, to avoid causing the diaphragm to take a “set” toward one extreme of travel or the other. 
         [0011]    In one embodiment, the diaphragm is devoid of openings and is sandwiched between components of a multiple piece actuating mechanism. 
         [0012]    In another embodiment, the diaphragm has a toroid configuration with the inner bead installed within the cooperating groove of a single piece actuating mechanism and with a membrane spanning the inner void, thereby making the diaphragm and actuating mechanism assembly devoid of openings. A variation of this embodiment, used in less demanding applications, omits the membrane spanning the inner void of the diaphragm to provide a true toroid configuration. 
         [0013]    These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a perspective view of a first embodiment of a pulse pump assembly according to the present invention, with the case shown partially broken away. 
           [0015]      FIG. 2  is an exploded perspective view of the pulse pump assembly of  FIG. 1 , showing its major components. 
           [0016]      FIG. 3  is a detailed perspective view of the pulse pump of  FIG. 1 , shown removed from the case. 
           [0017]      FIG. 4  is a detailed perspective view of the pulse pump of  FIGS. 1 through 3 , with the pump mechanism housing removed to show the interior mechanism. 
           [0018]      FIG. 5  is a flowchart describing the system operation. 
           [0019]      FIG. 6  is an exploded perspective view of the pump mechanism of  FIG. 4 , showing further details thereof. 
           [0020]      FIG. 7  is an exploded perspective view of an alternative embodiment pump mechanism, showing details thereof. 
           [0021]      FIG. 8A  is a front elevation view in section of the pump and mechanism of  FIG. 6 , showing the mechanism at one extreme of its travel. 
           [0022]      FIG. 8B  is a front elevation view in section of the pump and mechanism of  FIG. 6 , showing the mechanism at the opposite extreme of its travel from that shown in  FIG. 8A . 
           [0023]      FIG. 9A  is a front elevation view in section of the pump and mechanism of  FIG. 7 , showing the mechanism at one extreme of its travel. 
           [0024]      FIG. 9B  is a front elevation view in section of the pump and mechanism of  FIG. 7 , showing the mechanism at the opposite extreme of its travel from that shown in  FIG. 9A . 
           [0025]      FIG. 10  is a perspective view of another alternative embodiment of the pulse pump mechanism, incorporating multiple diaphragms and corresponding inlet and outlet valves. 
           [0026]      FIG. 11  is a bottom perspective view of the multiple diaphragm and valve pump assembly of  FIG. 10 , showing further details thereof. 
           [0027]      FIG. 12  is an exploded perspective view of the multiple diaphragm and valve pump assembly of  FIGS. 10 and 11 , showing further details thereof. 
           [0028]      FIG. 13  is an exploded perspective view of the multiple diaphragm and valve pump assembly of  FIGS. 10 through 12 , showing details of the individual diaphragms, valves, and actuating mechanisms and their relationships. 
       
    
    
       [0029]    Similar reference characters denote corresponding features consistently throughout the attached drawings. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0030]    The present invention comprises various embodiments of a pulse pump for delivering quantities of a fluid from a reservoir to a selected site. The pump is particularly well suited for dispensing a predetermined quantity of a biodegradation agent into the under-floor drain lines and drain tubes of beverage dispensers in restaurants and other locations where such dispensers are typically used, but may be applied to a number of other environments and industries where periodic transfer of a predetermined quantity of fluid is required. 
         [0031]      FIG. 1  illustrates the pulse pump assembly  10 , with  FIG. 2  providing an exploded perspective view of the major components of the pump assembly. The pump assembly  10  comprises an electric motor  12 , speed reduction gear system  14 , reciprocating or oscillating pump actuation mechanism  16 , diaphragm assembly  18 , pump body  20 , inlet check valve  22 , outlet check valve  24 , an inlet tube connector  26 , an outlet tube connector  28 , connecting tubes  30  and  32 , an electrical power switch (e.g., on-off switch)  34 , a control module  36  with an indicator light  54 , a reservoir  42 , and a battery holder  40  contained within a housing or case  44 . 
         [0032]    Pump body  20 , with inlet check valve  22 , outlet check valve  24 , inlet tube connector  26  and outlet tube connector  28  attached thereto, may be rotated on the axial centerline of actuator mechanism  16  in 90 degree increments to any orientation needed for a particular application. It will be further noted that by repositioning the locking tabs on the pump body during the molding process, the inlet and outlet check valves  22  and  24  and their appendages can be incrementally positioned to meet the needs of any application. It will also be noted that inlet and outlet tube connectors  26  and  28 , which have elbow configurations in the embodiment of  FIGS. 1 through 4 , can likewise be molded to allow incremental rotational orientation (as shown in  FIG. 3 ) or can be molded with either connector in a straight configuration (as shown in  FIG. 8A ). 
         [0033]    Electrical power for the motor  12  and other functions is provided through power switch  34  and on through a programmable control module  36  by one or more electrical storage cells  38  contained within a battery holder  40  within the housing or case  44 . Alternatively, electrical power may be obtained from a conventional electric power grid through a conventional step-down transformer or the like, with a conventional rectifier circuit provided where a d.c. motor is used. 
         [0034]    The pulse pump  10  is particularly well suited for the dispensing of a biodegradation agent in various environments, as noted further above. Accordingly, a reservoir  42  (plastic bag, etc.) is installed within the housing or case  44 , communicating with the inlet check valve  22  via inlet tube connector  26  and connecting tube  30 . The reservoir  42  includes a cap  43  ( FIG. 2 ) having a one-way suction relief valve  45  therein, i.e., a thin rubber disc or “umbrella” valve. This valve  45  is shown in broken lines in the cap  43  in  FIG. 2 , and allows air to flow into the reservoir  42  through a vent or relief passage  47  in the cap  43  as the biodegradation fluid is drawn from the reservoir. An outlet valve delivery tube  32  or the like ( FIG. 1 ) extends from the outlet check valve  24  and outlet tubing connector  28  to the targeted delivery site of the material being dispensed by the pump  10 . 
         [0035]      FIG. 3  of the drawings provides a perspective view of the pump assembly without the peripherals such as the power switch  34 , control module  36 , electrical storage cells  38 , connecting tubes  30  and  32 , and dosing material reservoir  42 , all of which are essential for the pulse pump to function. 
         [0036]      FIG. 4  of the drawings provides a view of the pump assembly  10  of the first embodiment with the cover of the actuator mechanism removed, to show more clearly the details of this mechanism. A non-circular output shaft  46  extends from the gear reduction drive  14 , and extends into or through an axially offset mating passage in an eccentric rotor  48 . As the output shaft  46  rotates, the rotor  48  oscillates eccentrically due to the non-concentric installation of the output shaft  46  therein. The rotor  48  resides within an oval-shaped passage  50  within the reciprocating diaphragm actuator  52 , which in turn drives the diaphragm assembly  18  as explained further below. The rotor  48  is free to oscillate laterally within the oval passage  50  of the actuator  52 , but the narrower vertical dimension (i.e., normal to the plane of the diaphragm) of the oval passage  50  results in the rotor  48  drawing the reciprocating actuator  52  upwardly and downwardly relative to the plane of the diaphragm (illustrated in other Figs.), thus reciprocating the diaphragm. More specific embodiments of the diaphragm, diaphragm actuator, and other components are shown in  FIGS. 6 through 9B , and described in detail further below. Certain components shown in  FIG. 4  are common to all of these embodiments, and have common reference numerals where applicable. 
         [0037]      FIG. 4  also illustrates another feature of the pulse pump, i.e., means whereby the pump drive is rotated sufficiently to reposition the diaphragm to a neutral or unstressed position during periods of inactivity. This is a useful feature as otherwise the drive system will always stop with the output shaft  46 , rotor  48 , diaphragm actuator  52 , and diaphragm positioned at or near an extreme of their travel. This would likely result in the diaphragm taking a “set” when held in such a distended position for a long period of time between pump actuation, thus affecting the accuracy of the delivery provided by the device  10  and possibly distending the diaphragm to the point that it incurs damage during subsequent operation. 
         [0038]    A light passage  56  is formed through the diaphragm actuator  52 , with a light source  58  (e.g., LED, etc.) disposed to one side of the actuator  52  and a light receptor  60  (e.g., phototransistor or photocell, etc.) disposed to the opposite side of the actuator. As the diaphragm actuator  52  and diaphragm assembly  18  are reciprocated by rotation of the eccentric rotor  48 , the light passage  56  periodically passes between the light source  58  and the opposite detector or receptor  60 , with the receptor  60  periodically detecting pulses of light when the light passage  56  is aligned therewith. The control circuit counts the number of times the pulse of light has been detected and when the preprogrammed number of pulses have been detected, the electronic circuit directs the motor drive to remain on to drive the motor through an additional quarter revolution, thereby stopping the motor and pump linkage with the diaphragm in the neutral or unstretched position. The circuit accomplishes this by using a divider system to divide the time between light pulses by four. The control module  36  can also be expanded to receive and process remotely generated signals, e.g., radio frequency (RF) or infrared (IR) signals or signals transmitted by wire from mechanical switches to change the number of preprogrammed pulses between each of a series of motor stoppages, thereby providing the ability to change the number of rotations between motor stoppages without physically accessing or removing the control module  36  for reprogramming the control circuit. 
         [0039]      FIG. 5  provides a flowchart illustrating the basic steps in the operation of the diaphragm centering or neutralizing system. Pump assembly components referred to in the discussion of the  FIG. 5  flowchart may be seen in various other Figs., particularly  FIGS. 1 and 6 . Conventional circuitry is used throughout for the following operation. The power switch  34  ( FIGS. 1 and 2 ) is initially actuated to actuate the pump motor  12 , as indicated by the first and second steps  62  and  63  in  FIG. 5 . The indicator light  54  is typically energized at this point to indicate the dispenser is in operation. The indicator light  54 , e.g., an LED or other suitable light, may be provided with the capability of emitting green, yellow, or red light to indicate or display various conditions. For example, normal operation may be indicated by a green light, with a flashing red light displayed if operational voltage drops below a certain predetermined value. 
         [0040]    The pulse pump is programmed to initially provide a relatively large dose of bioremediation fluid to the system, and then to provide periodic smaller maintenance doses over an extended period of time. When the power switch  34  is actuated (manually or remotely, if so provided), motor operation begins, as indicated by the second step  63  of  FIG. 5 . This causes liquid to be drawn from the reservoir, through the inlet check valve  22  (FIG.  1 , etc.) and into the chamber volume  108  ( FIG. 8A ) produced by the distension of the diaphragm, with the liquid being forced from the chamber  108  through outlet check valve  24  and on to the targeted treatment area. 
         [0041]    As motor operation continues, the control module  36  continually counts the number of light pulses developed by the periodic passage of the light passage  56  in front of the light source  58  ( FIG. 4 ), as indicated by the third step  64  of  FIG. 5 . So long as the preprogrammed number of light pulses has not been reached, the motor  12  continues to run. This operation continues without interruption, as indicated by the fourth and fifth steps  65  and  66  of the flowchart of  FIG. 5 . However, when the predetermined number of light pulses has been detected (step  65 ), e.g., forty pulses or ten revolutions (a larger or smaller number of pulses or revolutions may be programmed as desired or required), the control module  36  shuts off the motor  12 , as indicated by the fourth and sixth steps  65  and  67  of  FIG. 4 . 
         [0042]    Simultaneously with motor shutdown, a timer is activated. The timer deactivates the motor  12  for a predetermined period of time, e.g., forty-five minutes (longer or shorter rest times may be programmed, as desired). When the predetermined period of shutdown time has elapsed, as indicated by the seventh step  68  of  FIG. 5 , the control module  36  will reactivate the pump motor  12  for a short preprogrammed period, or more accurately, a short preprogrammed number of pulse detections, as indicated by the eighth step  69  of  FIG. 5 . By counting pulses during motor operation rather than operating the motor for a predetermined period of time, the proper number of revolutions (and therefore pump cycles) is assured, which might not be the case if the motor were to operate more slowly due to low voltage or some other reason. This operation continues until electrical power is discontinued to the circuit by shutting off the power switch  34  or otherwise interrupting electrical power to the device. 
         [0043]    It will be seen in  FIG. 4  that the light passage  56  is located toward one end of the diaphragm actuator  52 . Thus, when the light passage  56  is aligned with the light source  58  and receptor  60 , the actuator  52  (and diaphragm attached thereto) is positioned toward one extreme of their travel, i.e., toward the motor  12 , as shown in  FIG. 4 . Thus, if the light receptor  60  detects light, the system continues to operate (or reactivates) the motor  12  to drive the gear reduction output shaft  46  another quarter turn, thereby repositioning the diaphragm actuator  52  and diaphragm neutrally between the two extremes of travel. 
         [0044]    If no light is detected by the receptor  60  when power to the motor is interrupted, the actuator  52  and diaphragm may be at or toward the other extreme of their operating range. If this occurs, the system continues to operate the motor  12  until the light passage  56  is aligned with the light source  58  and receptor  60 . At this point the cycle reverts to that described above, i.e., the system operates the motor  12  to drive the output shaft  46  and rotor  48  another quarter turn to position the actuator  52  and diaphragm neutrally. 
         [0045]    The pulse pump may include different diaphragm and diaphragm holder or attachment configurations, as desired.  FIGS. 6 and 7  provide exploded perspective views of two such configurations. The configuration or embodiment of  FIG. 7  may be preferable in some operating environments, as it requires fewer parts and components than the embodiment of  FIG. 6 . 
         [0046]      FIG. 6  provides an exploded perspective view of an embodiment of the diaphragm actuator and diaphragm assembly in which the diaphragm is an unbroken disc devoid of openings or passages therethrough. The mechanism includes a multiple piece actuator housing assembly comprising an actuator housing  72 , essentially identical to the housing  72  of the embodiment of  FIG. 7 , with an actuator sleeve  92  sliding or reciprocating therein. The actuator sleeve  92  includes a circular diaphragm limit flange  94  extending therefrom that limits the upward motion (i.e., toward the output shaft and rotor passing through the actuator) of the central portion of the diaphragm. The diaphragm actuator  52  is immovably affixed within the actuator sleeve  92  to reciprocate with the sleeve  92  in the housing  72 , and includes a diaphragm attachment receptacle  96  therein. 
         [0047]    The diaphragm  80  of the embodiment of  FIG. 6  is a substantially circular unbroken disc devoid of openings therein, as noted further above. The diaphragm  80  includes a peripheral outer bead  98  that seats in and forms a seal with an internal circumferential groove (shown in  FIGS. 8A and 8B ) within the circular base  88  of the actuator housing  72 , with the base  88  also serving as the diaphragm housing as in the embodiment of  FIG. 7 . The diaphragm  80  of the  FIG. 6  embodiment further includes a central hollow bulb  100 , with an unbroken and impervious web  102  extending between the central bulb  100  and the outer bead  98 . 
         [0048]    The diaphragm  80  is secured to the actuator  52  by a circular diaphragm limit plate  104  having a diameter slightly less than that of the outer bead  98  of the diaphragm. The limit plate  104  includes a central diaphragm attachment knob  106  extending upwardly therefrom that fits within the hollow bulb  100  of the diaphragm  80 , with the bulb  100  and limit plate knob  106  inserted within the diaphragm attachment receptacle  96  of the actuator  52  when the mechanism is assembled as shown in  FIGS. 8A and 8B . The limit plate  104 , along with the overlying limit flange  94  of the actuator sleeve  92 , limits flexure and movement of the diaphragm  80  to the relatively narrow span between the outer edges of the limit flange and limit plate and the captured outer bead  98 , to provide consistency in volumetric pumping operations of the device. 
         [0049]      FIG. 7  illustrates an alternative embodiment that includes an actuator housing  72 , in which the actuator  74  slides or reciprocates back and forth in accordance with the operation described further above for the actuator  52  shown in  FIG. 4 . The diaphragm actuator  74  of the embodiment of  FIG. 7  includes a circular diaphragm attachment flange  76  formed as a unitary component thereof and extending therefrom, with the flange  76  having a diaphragm groove  78  formed peripherally therearound. The diaphragm  80   a  is of either a true toroid configuration with an open center  82 , or alternatively a configuration with a membrane  102   a  ( FIGS. 9A and 9B ) spanning the center, with an inner bead  84  fitting tightly within the diaphragm groove  78  of the actuator  74  and forming a seal therewith. The opposite outer bead  86  of the toroid diaphragm  80   a  seats in and forms a seal with an internal circumferential groove  98  (shown in  FIGS. 9A and 9B ) within the circular base  88  of the actuator housing  72 , with the base  88  also serving as the diaphragm housing. A resilient, flexible, and impervious web  90  extends between the two beads  84  and  86 , and serves as a moving seal for the variable internal volume of the pump during operation. 
         [0050]      FIGS. 8A and 8B  illustrate the two extremes in the position of the bulbed diaphragm  80  in the pump embodiment of  FIG. 6 . In  FIG. 8A , the reduction drive output shaft  46  has rotated the rotor  48  so that its high point is oriented upwardly, thus lifting or moving the diaphragm actuator  52  toward the motor  12 . As the actuator  52  is lifted, the actuator sleeve  92 , central portion of the diaphragm  80  with its bulb  100 , and the diaphragm limit plate  104  with its knob  106  are also lifted with the actuator  52 , due to the limit plate knob  106  and diaphragm bulb  100  being captured within the receptacle  96  of the actuator  52 . (It will be seen that the side elevation views in section of  FIGS. 8A and 8B  show the entire width of the actuator sleeve  92 , with its flange  94  being equal to this lateral width.) 
         [0051]    As the central portion of the diaphragm  80  is raised, a diaphragm chamber volume  108  is developed between the diaphragm  80  (and its lower limit plate  104 ) and the pump body  20  of the actuator mechanism  16 , from which the inlet and outlet valves  22  and  24  depend. As the chamber volume  108  increases with a corresponding drop in pressure, it draws the one-way inlet check valve  110  of the inlet valve assembly  22  open, thus drawing fluid into the diaphragm chamber volume  108 . The lesser pressure within the chamber volume  108 , and correspondingly greater pressure on the outlet side of the valve assembly, results in the one-way outlet check valve  112  of the outlet valve assembly  24  remaining closed during this portion of the pump operation. While the inlet and outlet check valves  110  and  112  are shown as “duckbill” type valves, it will be seen that any conventional one-way check valve configuration may be substituted for these duckbill valves  110  and  112 , e.g., flapper valves, reed valves, and/or poppet valves, all of which are conventional and well known for use as one-way check valves. 
         [0052]    In  FIG. 8B , the output shaft  46  has rotated 180 degrees from its position in  FIG. 8A , thus rotating the eccentric rotor  48  within the oval rotor passage  50  of the diaphragm actuator  52  so the high point of the rotor  48  is oriented downwardly, i.e., toward the diaphragm  80 . This pushes the actuator  52 , along with its attached actuator sleeve  92 , diaphragm  80 , and lower diaphragm limit plate  104 , downwardly within the actuator housing  72 , i.e., toward the check valve assemblies  22  and  24 . This reduces or eliminates the chamber volume  108  (shown in  FIG. 8A ), forcing any fluid contained therein through the outlet check valve  112 . The increase in pressure caused by the reduction of the chamber volume results in the inlet check valve  110  being forced closed. However, the orientation of the outlet duckbill (or other one-way valve type, as desired) of the outlet valve  112  causes this valve assembly to open, thus expelling the fluid from the pump and through the outlet tube connector  28  and outlet line, pipe, or tube  32  ( FIG. 1 ). The position of the diaphragm  80  is neutralized at the center of its travel by means of the light sensing and repositioning system shown in  FIG. 4  and discussed further above, when the pump is deactivated. 
         [0053]      FIGS. 9A and 9B  provide illustrations of the operation of the pulse pump embodiment of  FIG. 7 , i.e., wherein the diaphragm  80   a  has an inner bead  84  that seats within the diaphragm attachment groove  78  of the diaphragm actuator  74  and an outer bead  86  that seats within the an internal circumferential groove  98  within the circular base  88  of the actuator housing  72 . As the two beads  84  and  86  are captured by the structure of the actuator assembly, no central knob or the like is required for the diaphragm  80   a . Operation of the pulse pump of  FIGS. 9A and 9B  is essentially the same as that described above in the description of pump operation of  FIGS. 8A and 8B , with reciprocation of the rotor  48  and actuator  74  periodically changing the volume of the chamber  108  to pump fluid through the valve body  20 . 
         [0054]    A couple of different effects have been found in the operation of the pulse pump in its various embodiments, particularly when the outlet line  32  is relatively long. First of all, it has been found that the system will tend to siphon liquid from the supply through the two one-way valves when the power is off, once the system has been primed and the pump body  20  and its two pump assemblies  22  and  24  have been filled. The solution for this problem is the installation of an anti-siphon valve assembly  114  extending from the outlet valve body or assembly  24 . A third one-way valve  116 , e.g., another duckbill valve or equivalent, is installed within the anti-siphon valve body or assembly  114 , oriented in the opposite direction from the outlet valve  112 . The anti-siphon valve  116  allows air to flow into the valve body  20  by way of a breather hole or passage  118  in the cap enclosing the anti-siphon valve  116  in the assembly  114 . Thus, pressure greater than ambient, as occurs when the system is in operation, closes the anti-siphon valve  116 , with the valve  116  preventing the escape of liquid through the breather hole  118 . However, when the system is inoperative, any pressure therein less than ambient will cause the anti-siphon valve  116  to open, allowing air to flow into the valve body  20  and break the suction that would otherwise cause liquid to siphon through the system. 
         [0055]    The inclusion of such an anti-siphon valve  116  in the system provides another benefit as well. Typically, the pulse pump will be installed several feet above the drain line into which the biodegradation agent is pumped. Each pulse of the pump produces a relatively short stream of agent into the outlet or delivery tube, e.g., two milliliters volume results in a stream of material approaching eight inches long in a tube having a quarter inch internal diameter. However, if the pump is installed with a fall of several feet from pump to delivery tube outlet, it will be seen that the anti-siphon valve  116  will allow nearly all of the delivery tube to fill with air between pulses. This has the beneficial effect of pumping air (and therefore oxygen) into the system with the biodegradation agent, e.g., about a 9 to 1 ratio of air to agent in a typical installation. This ratio will of course vary depending upon the pump stroke volume(s), delivery line diameter, and distance of the delivery line fall to the drain. While the agent is capable of working without the presence of oxygen, it is much more efficient when oxygen is present. Thus, the anti-siphon valve  116  not only eliminates continued siphoning flow of the biodegradation agent through the pump(s) and delivery line when the system has been shut down, but also allows the biodegradation agent to work more efficiently as well by means of the oxygen introduced into the system by means of the anti-siphon valve. 
         [0056]    Another effect that has been found is that the withdrawal of liquid from the reservoir results in a partial vacuum being developed within the reservoir  42 . This results in the pump motor  12  having to work harder to overcome the vacuum, in addition to pumping the liquid from the reservoir  42  to the outlet line  32 . This results in greater energy consumption by the motor  12 , thereby depleting the battery or batteries  38  (if used) at a greater rate of discharge. The solution to this problem is the installation of a one-way valve  45  in the cap  43  of the reservoir  42 , as shown in  FIG. 2  of the drawings. The valve  45  may comprise a thin, flexible sheet of rubber or other suitable material that covers a breather hole or passage  47  in the cap  43 , i.e., an “umbrella” type valve or the like. A duckbill valve, as shown in the one-way inlet and outlet valve system, may be incorporated in lieu of such an “umbrella” valve, if desired. When ambient pressure is greater than the pressure within the reservoir  42 , the pressure pushes the valve  45  open to allow air to flow into the reservoir  42  to relieve the partial vacuum therein and reduce the load on the pump motor  12 . 
         [0057]      FIGS. 10 through 13  provide illustrations of yet another embodiment of the pulse pump, in which the pump includes multiple inlet and outlet valve assemblies. This has the benefit of producing greater fluid flow or output per each revolution of the rotor, as well as greatly reducing the pressure fluctuations per revolution produced by a pump having a single inlet and outlet valve assembly. 
         [0058]    The multiple valve pulse pump  210  of  FIGS. 10 through 13  comprises a central assembly much like that of the pulse pump  10  in its various embodiments, i.e., having an electric motor  12 , speed reduction gear system  14 , and reciprocating or oscillating pump actuation mechanism as in other embodiments. However, the pump actuation mechanism drives a series of four separate diaphragm assemblies, respectively  218   a  through  218   d . Each of the diaphragm assemblies is driven by a plate, respectively  220   a  through  220   d  ( FIG. 13 ), with the four plates overlapping one another within the housing. Each plate  220   a  through  220   d  has an oval shaped passage, respectively  222   a  through  222   d , therethrough, with the eccentric rotor  48  being captured within the plate passages. Thus, as the rotor  48  is rotated by the gear reduction output, it oscillates within the passages  222   a  through  222   d  of the plates  220   a  through  220   d , thereby causing each of the plates to reciprocate in turn with each succeeding plate trailing 90 degrees behind the previous plate in their cycles. 
         [0059]    Each plate  220   a  through  220   d  drives a diaphragm, respectively  80   a  through  80   d  (they may be identical to the diaphragm  80   a  of  FIGS. 7 ,  9 A, and  9 B). Each of the diaphragms in turn varies the volume of its respective diaphragm chamber  208   a  through  208   d , essentially as in the pulse pump embodiments described further above. Each of the diaphragm chambers  208   a  through  208   d  has a pump body, respectively  20   a  through  20   d , extending therefrom. Each pump body in turn includes an inlet valve assembly, respectively  22   a  through  22   d , and an outlet valve assembly, respectively  24   a  through  24   d , extending therefrom. Each inlet valve assembly includes a one-way inlet valve  110  installed therein, with each outlet valve assembly having a one-way outlet valve  112  disposed therein. 
         [0060]    The first inlet valve assembly  22   a  has an inlet line connector or fitting  26   a  extending therefrom, which would connect to the supply line  30  from the reservoir  42  if the pump assembly  210  were installed in lieu of the pump assembly  10  of  FIG. 1 . The opposite outlet line connector or fitting  28   a  communicates with the second inlet connector or fitting  26   b  of the second inlet valve assembly  22   b  via an intermediate tube  30   a . In a like manner, the outlet fitting  28   b  of the second outlet valve assembly  24   b  communicates with the inlet fitting  26   c  of the third inlet valve assembly  22   c  via another intermediate tube  30   b , with the third outlet fitting  28   c  of the third outlet valve assembly  24   c  communicating with the inlet fitting  26   d  of the fourth inlet valve assembly  22   d . Finally, the outlet fitting  28   d  of the fourth outlet valve assembly  24   d  connects to an outlet line, e.g., the line  32  of the pump assembly shown in  FIG. 1 , if the multiple valve pump  210  were used in lieu of the single valve pump shown in  FIG. 1 . Thus, the valve assembly series  22   a  through  24   d  of the multiple valve pump embodiment  210  operates progressively in sequence as the rotor  48  progressively reciprocates each of the diaphragm drive plates  220   a  through  220   b , with the output of the first outlet valve assembly  24   a  delivering its fluid to the second inlet valve assembly  22   b , etc., with fluid passing through each of the inlet and outlet valves in sequence until passing from the system through the fourth outlet valve outlet fitting  28   d . The result is a much more uniform delivery of fluid, greatly reducing the pressure pulses occurring when a single diaphragm and valve assembly are used. 
         [0061]    Otherwise, it will be seen that the multiple diaphragm and valve pulse pump system includes various features found in the various embodiments of the single diaphragm assembly  10  of  FIGS. 1 through 9B . For example, the fourth or final outlet valve  24   d  includes an anti-siphon valve assembly  114  extending therefrom, which function is identical to that described further above for the pulse pump embodiment  10 . It will also be seen that while a series of four diaphragms  80   a  through  80   d  and corresponding valve bodies  20   a  through  20   d , inlet valve assemblies  22   a  through  22   d , and outlet valve assemblies  24   a  through  24   d  with their inlet and outlet valves  110   a  through  112   d  are shown in  FIGS. 10 through 13 , other arrangements or configurations may be constructed in keeping with the concept described above. For example, two of the four diaphragm actuator plates may be eliminated during assembly, with only two diaphragms and two inlet and outlet valve assemblies remaining operable and interconnected. Alternatively, the central body of the assembly may be reconfigured to provide an odd number of diaphragm assemblies and drives, e.g., three, five, etc., as desired. Moreover, it will be seen that multiple rows of valve assemblies may be stacked relative to one another, with an elongate rotor driving additional rows of diaphragms, depending upon the power output of the drive motor used. 
         [0062]    In conclusion, the pulse pump in its various embodiments works well for the delivery of relatively small quantities of precisely metered fluids, e.g., for biodegradation of biodegradable products in the restaurant industry or other environments requiring high levels of sanitation. The different diaphragm and actuator embodiments may be used as desired, with each having certain benefits relative to the other. The pulse pump is preferably configured for essentially automatic operation, with a timer system actuating the pump periodically and for a predetermined amount of time as required. Appropriate annunciator lights may be provided as well to warn of low material supply, low battery power, etc. as desired. Accordingly, the pulse pump in its various embodiments is a most useful accessory in the restaurant and other industries where the precise automated periodic metering or dispensing of a small quantity of fluid is required from time to time. 
         [0063]    It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.