Abstract:
The scum removal system for liquids is adaptable to wastewater treatment facilities, aquaculture facilities, oil spills, and/or other environments where the removal of a thin, buoyant layer of material from a liquid surface is desired. The system incorporates a geyser pump having one or more inlet pipes, with the inlet pipe(s) collectively having a larger diameter than the discharge pipe. This assures that the volume of water in the inlet pipe is always less than that in the discharge pulse, thus assuring that a steady, constant flow of liquid flows into the inlet opening to assure a uniform inertial flow of the floating contaminants into the inlet. The top of the inlet pipe(s) may be vertically adjustable for variable liquid level. The geyser pump may be submerged within the liquid or may be installed external to the liquid tank with the submerged inlet pipe communicating with the external pump.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/716,849, filed Oct. 22, 2012. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to water treatment systems, and particularly to a scum removal system for liquids wherein a constant flow is maintained into the intake pipe to the geyser pump to draw surface scum from the liquid. 
     2. Description of the Related Art 
     Quiescent bodies of impure or contaminated water or other liquids will often have a buoyant layer of material floating thereon, with removal of this buoyant layer being desirable for environmental and/or other reasons. An example of such is often found in the conventional secondary clarifier tank or lagoon in a wastewater treatment plant or facility. The function of such secondary clarifier tanks is to allow the wastewater to become quiescent, so solids may settle out. However, this also allows buoyant materials to rise to the surface of the water, in the form of scum. Such scum can impede discharge performance of pumps in the system, and also generally result in undesirable odors due to the organic decomposition occurring in such scum residue. 
     Accordingly, various means of scum removal have been developed in the past. Generally, two different principles have been applied to scum removal in wastewater treatment facilities and other situations where scum removal is desired. One such scum removal principle utilizes flat skimmer blades or paddles to remove the scum from the surface mechanically. These mechanical skimmer systems tend to require a fair amount of maintenance and can require considerable power to operate. Another scum removal system utilizes a pneumatic airlift pump to draw the scum into an inlet at the surface of the water. Airlift pumps operate by introducing air into the bottom of a substantially vertical tube disposed within the water, with the air reducing the density of the water or other liquid in the tube and causing the air and liquid mix to rise to the top of the tube where it is ejected from the tube. Airlift pumps have the advantages of simplicity and lack of moving parts in the immersed pump assembly, but produce relatively weak suction for the power required and thus limit the effective surface area that may be treated by such a pump. Such airlift pumps are also prone to clogging under certain circumstances, due to the relatively slow movement of liquid and air through the discharge pipe. 
     A more recent development has been the geyser pump, which operates by accumulating a relatively large charge of air at the lower end of the pump riser, which results in the air charge being released as a single volume to travel up the riser or discharge pipe of the pump. This increases the periodic lifting force up the discharge pipe to carry an equal amount of liquid (and contaminants, if any) up the discharge pipe with each pulse of air. As in the case of the airlift pump, the rate of flow may be adjusted by adjusting the flow of incoming air to the pump. The relatively powerful lifting action of the geyser type pump is generally used to lift sediment from the bottom of a tank or pond, or to circulate the water or liquid from the bottom of the tank or pond. The relatively powerful action also tends to prevent clogging or buildup of foreign matter within the discharge pipe. 
     However, the cyclic or pulsing operation of such geyser pumps results in a corresponding cyclic or pulsing flow to the pump inlet. This may be of no great concern where the inlet is submerged, but this pulsing flow has precluded the use of the geyser pump principle for use in scum removal from the surface of a liquid, even though the relatively greater lifting power of the geyser pump provides significant advantages otherwise. Accordingly, there has been no motivation to provide an inlet opening at the water or liquid surface to draw floating scum into the geyser pump for discharge to another area, or to provide vertical adjustment for such an inlet to allow for varying liquid levels. 
     Thus, a scum removal system for liquids solving the aforementioned problems is desired. 
     SUMMARY OF THE INVENTION 
     The scum removal system for liquids is adaptable to waste water treatment facilities, aquaculture facilities, oil spills, and/or other environments where the removal of a thin, buoyant layer of material from the surface of a body of water or other liquid is desired. The scum removal system incorporates a geyser type pump with an inlet disposed at the surface of the liquid, to draw floating scum from the surface and into the inlet to be pumped to another location by the geyser pump. Smooth and continuous flow into the inlet is provided by having an inlet pipe of significantly larger diameter than the outlet pipe of the pump. The larger diameter inlet pipe provides an internal volume larger than that of the discharge line, assuring that the inlet pipe can never fill completely between pump input cycles to stop flow or produce backflow at the inlet opening. This results in continual flow into the inlet opening to maintain the inertia of the inflow to the inlet and avoid pulses that would otherwise cyclically push back the inflow of liquid and scum into the inlet to destroy the inertial flow. 
     The larger diameter inlet pipe may comprise a single pipe of larger diameter than the outlet or discharge pipe, or a plurality of inlet pipes collectively having a larger diameter than the outlet or discharge pipe. The inlet pipe or pipes preferably includes a vertically adjustable inlet opening, allowing the height of the opening to be adjusted as necessary for varying liquid level. At least the inlet and discharge pipes are constructed of plastic pipe or other non-corrosive materials, with the pump also preferably being constructed of such non-corrosive material. The pump may thus be installed within the body of liquid being treated, or externally to the body of liquid with the intake and discharge pipes communicating with the body of liquid and the pump accordingly. 
     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 
         FIG. 1  is an environmental elevation view of a first embodiment of a scum removal system for liquids according to the present invention, shown within a settling tank and illustrating its basic components and structure. 
         FIG. 2  is an environmental elevation view of a second embodiment of a scum removal system for liquids according to the present invention, wherein the pump is disposed in a compartment external to the liquid tank. 
         FIG. 3  is an environmental elevation view of a third embodiment of a scum removal system for liquids according to the present invention, wherein plural intake pipes are provided to the pump. 
         FIG. 4A  is a detailed partial elevation view of the adjustable height inlet of the scum removal system for liquids according to the present invention, showing the inlet height adjusted downwardly for a lower water level. 
         FIG. 4B  is a detailed partial elevation view of the adjustable height inlet of the scum removal system for liquids according to the present invention, showing the inlet height adjusted for a medial water level. 
         FIG. 4C  is a detailed partial elevation view of the adjustable height inlet of the scum removal system for liquids according to the present invention, showing the inlet height adjusted upward for a higher water level. 
         FIG. 5  is a schematic elevation view of a prior art geyser pump for use with the scum removal system for liquids according to the present invention. 
     
    
    
     Similar reference characters denote corresponding features consistently throughout the attached drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The scum removal system for liquids incorporates a geyser type pump with suitable inlet and outlet pipes to provide a continuous inlet flow in order to avoid backups at the inlet that would disrupt the surface flow of liquid therein. The system further includes an adjustable height inlet to allow for varying liquid levels. Several embodiments are disclosed. 
       FIG. 1  of the drawings illustrates a first embodiment  110  of the scum removal system incorporating a single inlet pipe  112  and a geyser pump  114  immersed within the settling tank  116 . The geyser pump  114  has an essentially closed lower end  118  with the exception of the bottom intake inlet  120 , and an opposite upper end  122  with an upper pneumatic inlet  124  and an upper discharge outlet  126 . The geyser pump  114  contains no moving parts, but rather accepts gas (universally air) under pressure from a remote pump or other source of air or gas pressure through the pneumatic intake pipe  128  extending from the upper pneumatic inlet  124 . The air builds in volume within the geyser pump  114 , and results in a sudden discharge of air (and liquid and perhaps solids entrained therewith, if any) through the discharge outlet  126  and its discharge pipe  130 . 
     The conventional geyser pump has an open lower end or inlet to draw liquids and any solids entrained therein, into the bottom of the pump for discharge through the discharge pipe. Such a conventional geyser pump is illustrated schematically in prior art  FIG. 5 , and discussed further below. The inlet of the conventional geyser pump is not situated above the pump, but instead comprises an open lower pump end. However, the inlet pipe  112  of the present scum removal system  110  and its other embodiments have their inlet pipes, e.g., the inlet pipe  112 , connected to the bottom intake inlet  120  of the pump  114  by a generally U-shaped coupling  132  (e.g., two elbows joined end-to-end as shown, or other means of accomplishing such a 180 degree change in orientation) having a pump connection end common with the bottom intake inlet  120  of the pump  114  and an opposite intake pipe connection end  134 . The intake pipe  112  extends generally vertically upward from the intake pipe connection  134  of the U-coupling  132 , to an inlet  136  above the geyser pump  114  at the surface S of the liquid within the tank  116 . 
     The scum removal system  110  draws liquid and any scum floating thereon from the surface S of the liquid by means of the geyser pump  114  and the inlet  136  of the inlet pipe  112  at the surface S of the liquid. Constant flow of liquid into the inlet  136  is enabled by providing a relatively large diameter inlet pipe  112  in comparison to the discharge pipe  130 . It will be noted in  FIG. 1  that the inlet pipe  112  has a diameter D 1 , while the discharge pipe  130  has a somewhat smaller diameter D 2 . For example, the diameter D 1  of the inlet pipe  112  may be on the order of 1.5 times the diameter D 2  of the discharge pipe  130 , to provide an inlet pipe cross-sectional area on the order of 2.25 times the cross-sectional area of the discharge pipe  130 . These relative diameters and cross-sectional areas are exemplary, and other pipe sizes may be used as desired so long as the inlet pipe diameter D 1  is sufficiently larger than the discharge pipe diameter D 2 . 
     The difference in diameter results in a constant flow into the inlet pipe  112 , as its larger internal volume cannot fill between discharges in the smaller diameter discharge pipe  130 . This results in a constant flow of liquid from the surface S of the settling tank  116 , into the inlet  136  of the inlet pipe  112 . This constant flow results in constant momentum of the surface layer of liquid and any scum floating thereon into the inlet  136  of the inlet pipe  112 , rather than intermittent flow as a smaller diameter inlet pipe periodically fills between discharges of the pump through the discharge pipe. The periodic filling of the conventional smaller diameter inlet pipe results in no flow into the inlet pipe, with the momentum of the surface flow (and any scum floating thereon) stopping as the inlet pipe is filled. In fact, there is generally some slight backflow when the pipe becomes filled under such circumstances, which tends to wash away from the pipe inlet any scum that may be floating atop the liquid. When the liquid level in the inlet pipe lowers as a discharge of air and liquid occurs through the discharge pipe, liquid once again begins to flow toward and into the inlet pipe. However, the acceleration of the liquid mass (and any scum floating thereon) takes some finite amount of time to return to the pipe inlet and begin to flow into the inlet pipe. The constant flow provided by the larger diameter inlet pipe and geyser pump of the present system provides much greater efficiency in scum removal than earlier systems. 
     The liquid level within the tank  116  (or settling pond, etc.) may vary over some period of time. Accordingly, the intake or inlet end  136  of the inlet pipe  112  is vertically adjustable. This is accomplished by means of a vertically adjustable telescoping assembly  138 , such as a telescopic repair coupling available for the repair of a broken section of pipe. Such repair couplings may be inserted between the ends to replace the broken or damaged section, and adjusted by telescoping the assembly to fit the span between the broken ends. In the present invention, the telescopic repair coupling is connected at one end to the upper end of the fixed inlet pipe  112 , with the opposite end of the repair coupling becoming the vertically adjustable inlet opening  136  of the inlet pipe. Other telescoping assemblies for adjusting the level of the inlet end  136  to be level with or very slightly below the liquid surface S may be provided alternatively. 
     The telescoping inlet assembly  138  is provided with an upwardly extending extension handle  140 , to allow the height of the inlet opening  136  to be adjusted without need to reach into the water or other liquid within the tank  116 . The extension handle  140  is connected to the telescoping inlet assembly  138  by cylindrical segments  142  of pipe extending from an adapter at the base of the extension handle  140  to the inlet end  136  of the telescoping assembly  138 . These segments  142  have relatively wider upper ends  144  than their lower ends  146 , with the segments  142  defining diametrically opposed inlet openings  148  therebetween. The relatively narrower lower ends  146  of the pipe segments  142  result in relatively wider areas at the lower ends of the openings  148  to improve inflow at the lower ends where they attach to the upper end of the telescoping assembly  138 . 
       FIG. 2  illustrates an alternative embodiment  210 , wherein the geyser pump  114  is situated in a dry area or compartment  250  external to the settling tank  116 . Most of the components of the scum removal system  110  of  FIG. 2  are identical to those like components in the embodiment  110  of  FIG. 1 , i.e., the inlet pipe  112 , geyser pump  114 , settling tank  116 , pump lower end  118  and bottom intake inlet  120 , pump upper end  122 , upper pneumatic inlet  124  and upper discharge outlet  126 , intake pipe  128 , discharge pipe  130 , intake connection  134  to the inlet pipe  12 , inlet  136  of the inlet pipe  112 , telescoping inlet assembly  138 , extension handle  140 , and the various components and features  142  through  148  of the structure between the extension handle  140  and the inlet  136  of the inlet pipe  112 . However, the U-shaped inlet coupling  132  of the embodiment  10  of  FIG. 1  is replaced with an elongate length of angled pipe  252  between two 45° fittings  258  to form an expanded coupling or connection between the pump  114  and the inlet pipe  112  and its components. This allows the inlet pipe  112  and its components to be situated within the tank  116 , while the geyser pump  114  is located in a dry area or compartment  250  external to the settling tank  116 , separated from the settling tank by a wall or bulkhead  256 . As all of the inflow and outflow of the geyser pump  114  is by means of inlet and discharge pipes  112 ,  128 , and  130 , the pump  114  need not be located within the liquid tank  116  with the inlet pipe  112 , but may be separated from the liquid tank insofar as practicable, if so desired. 
       FIG. 3  of the drawings illustrates another alternative embodiment designated as scum removal system  310 , wherein two inlet pipe assemblies  112   a  and  112   b  are provided. The system  310  of  FIG. 3  is similar to the system  110  of  FIG. 1 , in that the geyser pump  114  is located within the liquid tank  116 . However, two separate inlet pipes  112   a  and  112   b  provide liquid flow to the pump  114 . The various components of the two inlet pipes  112   a  and  112   b  are essentially the same as the corresponding components of the single inlet pipe  112  of the embodiments  110  and  210  of  FIGS. 1 and 2 , but are designated by lower case letters a and b to indicate their installation with the corresponding inlet pipe  112   a  or  112   b . The first inlet pipe  112   a  is connected at its intake connector end  134   a  to the geyser pump  114  by a tee fitting  358  installed between the elbow  254  and the 45° fitting  258 , with the second inlet pipe  112   b  being connected at its intake connection end  134   b  to a second 45° fitting  258  and connector pipe  252  to the tee  358 . In this manner, the collective cross-sectional area of the multiple inlet pipes  12   a  and  12   b  may be increased over the area of a single pipe  12 , without increasing the diameter of either of the pipes  12   a  or  12   b  over the diameter of the single pipe  12 . It will be seen that additional inlet pipes as desired may be connected to the pump  114  in a similar manner, using conventional pipe fittings. Different pipe components may be used to further separate the inlets  136   a  and  13   6   b  from one another at the liquid surface S, as desired. A baffle  360  (shown in broken lines in  FIG. 3 ) may be disposed between the two inlet pipes  112   a  and  112   b , as desired. The various components of the geyser pump  114 , i.e., the bottom  118  and its intake inlet  120 , the top  122  and its pneumatic inlet  124  and discharge outlet  126 , and the associated pneumatic inlet pipe  128  and discharge pipe  130 , are essentially as shown in  FIGS. 1 and 2  and described further above. While the geyser pump  114  is shown as being installed within the liquid tank  116  in  FIG. 3 , it will be seen that it may be installed externally to the tank  116  if so desired, generally as shown in  FIG. 2 . 
       FIGS. 4A through 4C  illustrate the adjustment of the telescoping inlet assembly  138  for different liquid levels. The various upper end components  140  through  148  of each inlet pipe  112  are identical in each of the  FIGS. 4A through 4C , with only their relative heights changing between the three  FIGS. 4A through 4C .  FIG. 4A  illustrates a liquid level or surface S 1  at a relatively low level in comparison to the liquid levels S 2  and S 3  respectively of  FIGS. 4B and 4C . Accordingly, the telescoping inlet assembly  138  of  FIG. 4A  is adjusted to a relatively low level to place the lower edge of the inlet opening  136  at or very slightly below the liquid level surface S 1 , with relatively little of the lower collar  139  of the telescoping assembly  138  being exposed.  FIG. 4B  illustrates the telescoping assembly  138  adjusted for a medial height liquid level surface S 2 , with somewhat more of the collar  139  being exposed. In  FIG. 4C , the liquid level surface S 3  is relatively high, necessitating the raising of the telescoping assembly  138  to a higher level upon its lower collar  139  to expose more of the lower collar  139 . 
       FIG. 5  provides a schematic diagram of the internal structure of a conventional geyser pump G. In  FIG. 5 , the geyser pump G is installed in a liquid tank T, corresponding generally to the tank  116  of  FIGS. 1 through 3  of the drawings. The geyser pump G has an open bottom end B, allowing the open lower end E of the discharge pipe P within the open bottom end B of the pump to receive liquid (and perhaps sediment) from the bottom of the tank T. An air source A (pressurized air or gas from a compressor, etc.) delivers air or gas to the geyser pump G through an inlet pipe I. The air is supplied to an internal U-shaped pipe U. Due to the U-shaped pipe, air remains trapped in the air cylinder until it reaches a predetermined pressure, and then it is suddenly released through the discharge pipe P, expelling liquid and associated particulates. 
     As the geyser pump has no mechanical components or electrical connection, the geyser pump is not affected by a dry run condition should water levels fall below the top of the intake pipe or should the intake be raised above the water level. The air would continue to flow out of the discharge and/or intake pipe until the water enters the intake once again. A conventional submersible electric pump is subject to burnout in such a run dry condition. As the conventional geyser pump G has no upper inlet to receive liquid from near the surface, it cannot draw scum from the surface, as provided by the present scum removal system in its various embodiments. 
     Accordingly, the present scum removal system with its inlet at or slightly below the surface of the liquid and its larger diameter inlet pipe or pipes relative to its discharge pipe diameter, provides a means for assuring continuous flow into the inlet to preclude backflow and subsequent repulsion of liquid and scum floating thereon from the inlet. The result is a smoothly flowing input of surface liquid and scum into the inlet in a continuous flow, providing a considerably more efficient scum removal system than developed in the past. 
     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.