Abstract:
A concrete strainer used to separate water from wet concrete can include a volume enclosed by a screen or holes in perforated material, connected to a vacuum hose. An extender pipe can be inside the volume and also connect to the vacuum hose. The screen or holes prevent aggregates in the concrete from entering the vacuum hose and clogging an attached vacuum pump. Advantageously, when the strainer is partially submerged into the wet concrete a portion of the strainer exposed to air allows water to flow by gravity into a bottom of the strainer. The extender pipe, being submersed in said water, prevents a vacuum from being lost due to exposure to air pressure.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 11/743,012, filed May 1, 2007, which claims the benefit of U.S. Provisional Application No. 60/798,211 filed May 6, 2006. This application claims priority to both of the above referenced applications, the entirety of each being expressly incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to improvements in washout of concrete apparatus and collection of the washout liquids for transportation to an environmental disposal site and collection of waste solids as blocks of a manageable size for disposal. 
       BACKGROUND 
       [0003]    Concrete pumps are used to move concrete from concrete trucks to the places on a construction site where it is needed and where the concrete trucks cannot go. There are many types of pumps, including boom pumps, city pumps, line pumps and grout pumps. These concrete pumps typically have an inlet hopper where the concrete trucks deliver metered amounts of liquid concrete by means of a chute. The pump takes the concrete from the hopper and forces it through a series of pipes, hoses, or both, to the place on the construction site where it is used. These pumps and the chute of the concrete truck must be washed clean of waste concrete before the fluid concrete begins to harden. Environmental laws and restrictions on the disposal of this washout water and waste concrete are very strict. 
         [0004]    Large construction sites will usually have a washout facility for use by the concrete trucks and pumps. A disposal pit is dug into the ground and is lined with plastic sheet to prevent seepage into the earth. The waste concrete and washout water is deposited in the pit and as the pit is filled and the concrete hardens, the large heavy slab is hauled off to a remote disposal site. One problem with this approach is the potential for an environmentally prohibited seepage into the ground. A newer method is to use a large transportable metal container instead of digging a pit. In either case, the concrete pump and concrete truck must be moved to the pit and sometimes a wait is involved before the pit is available, before the pump or truck chute can be washed out. Moreover, many concrete pumping jobs involve improvements to existing structures, and are located in cities or towns, where there is no room for a washout facility. To make matters worse, concrete trucks and pumps must operate on paved roads, or in landscaped areas where no contamination by waste concrete will be tolerated. 
       SUMMARY 
       [0005]    The systems and methods disclosed herein provide environmentally sustainable modes of operating concrete pumps so that the onsite spillage of washout water and waste concrete is substantially eliminated. In one embodiment, the waste water and waste concrete from the pump clean-out are caught in a tub. The liquids are then removed from the tub with a suction water-solid separator. This water-solid separator removes a substantial amount of liquid from the tub to a storage tank for re-use or removal to an environmentally approved discharge site. The remaining water and waste concrete hardens into easily disposed of blocks of concrete of manageable size which are easily hauled away or used on-site as fill material or other purposes. 
         [0006]    Another mode of use provides for thorough washout of the chute of the concrete truck without any spillage of concrete or washout water. In this mode, washout water and waste concrete from the chute are dumped into the concrete pump hopper. The suction water-solid separator evacuates the used washout water from the hopper back into the cement truck for later disposal or re-use. 
         [0007]    In one embodiment, the system is implemented by a suction water-solids separator connected by vacuum base to a vacuum pump which discharges the evacuated water into a tank disposed on the truck or trailer hauling the cement pump. 
         [0008]    For purposes of this summary, certain aspects, advantages, and novel features of the invention are described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  illustrates a concrete pump installed on a trailer pulled by a truck on which a washout system is installed. 
           [0010]      FIG. 2  is a perspective view of another embodiment wherein both the concrete pump and washout system are installed on a truck. 
           [0011]      FIG. 3  is a perspective view illustrating use of a concrete pump delivering concrete to a site remote from the concrete truck. 
           [0012]      FIG. 4A  is a cross-sectional view of the washout tub and water-solid separator unit. 
           [0013]      FIG. 4B  is another cross-sectional view of the washout tub and water-solid separator. 
           [0014]      FIG. 5  is a perspective view of another embodiment of the washout tub. 
           [0015]      FIG. 6A  is a perspective view of the washout tub and discard concrete partitioning device. 
           [0016]      FIG. 6B  is a perspective view illustrating use of the discard concrete partitioning device to mold manageable concrete blocks. 
           [0017]      FIG. 7  illustrates an embodiment where the washout system is used to wash out the chute of the concrete truck. 
           [0018]      FIG. 8  is a detailed right side horizontal view of one embodiment of the washout water holding tank shown in  FIGS. 1 and 2 . 
           [0019]      FIG. 9  is a detailed front horizontal view of the washout water holding tank shown in  FIGS. 1 and 2 . 
           [0020]      FIG. 10  is a detailed left side horizontal view of the washout water holding tank shown in  FIGS. 1 and 2 . 
           [0021]      FIG. 11  is a detailed bottom view of the washout water holding tank shown in  FIGS. 1 and 2 . 
           [0022]      FIG. 12  is a detailed top view of the washout water holding tank shown in  FIGS. 1 and 2 . 
           [0023]      FIG. 13  illustrates one embodiment of the water-solid separator. 
           [0024]      FIG. 14  is a cross-sectional view of the water-solid separator taken along lines  14 - 14  of  FIG. 13 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Concrete Pump System 
       [0025]    Referring now to  FIGS. 1 ,  2 , and  3 , a concrete pump  25  is typically mounted on a trailer  26  pulled by a truck  27  (see  FIGS. 1 ,  3 ) or on a truck  27  (see  FIG. 2 ). By way of specific example, the typical concrete pump  25  uses a ram piston in which a cylinder is filled with concrete during the backstroke of the piston. A forward stroke of the piston pushes the concrete through the concrete pump outlet  36  into a pipeline  30  leading from the concrete pump  25  to the remote job site  31  (see  FIG. 3 ). However, the apparatus and methods described below are not limited to any particular type of concrete pump and have utility for cleaning any type of concrete pump. 
         [0026]    A typical concrete pumping situation is shown in  FIG. 3 . A concrete truck  32  is driven up to the concrete pump  25  mounted on truck  27  or trailer  26  and discharges mixed concrete from chute  33  into hopper  34  mounted on the concrete pump truck  27  or trailer  26 . The concrete pump  25  withdraws concrete from hopper  34  and forces the liquid concrete mixture through outlet  36  into the pipeline  30  leading to the job site  31 . Pipeline  30  may be rigid pipes, flexible hoses, or a combination thereof. 
         [0027]    When the necessary concrete mixture has been pumped or at the end of the work day, the concrete pump  25  must be washed clean of any remaining concrete mixture. 
       Concrete Pump Washout 
       [0028]    The embodiments described herein perform the concrete pump washout very efficiently and in an environmentally correct manner. Referring to  FIG. 2 , a tub  35  is positioned below the cleanout outlet  37  of hopper  34 . Such a cleanout outlet  37  is standard with concrete pump hoppers and is normally located on the bottom of hopper  34 . This outlet is opened as shown in  FIG. 2 , at the start of the washout procedure so that leftover concrete and washout water flow out of the bottom of hopper  34  through cleanout outlet  37  into tub  35 . Typically, the pipeline  30  in  FIG. 3  is also disconnected from the outlet  36  of the concrete pump before the washout of concrete pump  25 . Washout water is then sprayed into the hopper  34  and the concrete pump outlet  36  while, in one embodiment, the concrete pump  25  is run in reverse to withdraw into hopper  34  the concrete left over in the concrete pump  25 . Thus, the waste concrete in pump  25  and the washout water sprayed into outlet  36  are withdrawn from the concrete pump  25  and flow into hopper  34 . This waste concrete and wash water then flow through the cleanout outlet  37  of the hopper  34  into tub  35 . 
         [0029]    Some concrete pumps do not reverse. Typically they include a swing away assembly that provides access to the pump assembly at the rear of the hopper. For this type of pump, the tub  35  is positioned at the rear of the hopper to collect the waste concrete. 
         [0030]    Suction water-solid separator unit  40  is placed into tub  35  as shown. The washout water in tub  35  is filtered to remove all but fine particles of concrete by suction water-solid separator unit  40  and the filtered water delivered to storage tank  50 . As shown, separator unit  40  is attached to a vacuum suction hose  41  extending from an intake port  45  of a wash water pump  46 . The outlet port  47  of this wash water pump  46  is connected by hose  51  to the waste water storage tank  50 . As described in detail below, the separator unit  40  can be partially submerged into the waste concrete collected in tub so that when washwater pump  46  is turned on, the filtered waste water collected in tub  35  is withdrawn through hose  41  into the waste water storage tank  50 . Unit  40  evacuates a substantial portion of the washout water sprayed into hopper  34  and into concrete pump outlet  36 . Not all of the water need be evacuated from the tub  35 , rather the amount of water to be removed is the amount necessary to achieve the environment goal of removing substantially all the liquid and solid waste from the job site without spilling liquids or liquid concrete onto the ground. So long as the washout water remaining in the tub  35  is either evaporated or absorbed by the concrete waste to form solid concrete after setting, this goal will be achieved. 
         [0031]    After washout of the concrete pump  25  has been completed, the cleanout outlet  37  in hopper  34  is closed and the tub  35 , then holding only a small amount of water, can be slid from beneath the hopper  34 . 
         [0032]    With the wash water pump  46  still running, the separator  40  can be placed into a bucket of water for cleaning with the wash water being evacuated to tank  50 . The separator  40  is then removed from the vacuum hose  41 . Water from a water hose is then sprayed into the open end of the vacuum suction hose  41  for cleaning both the hose  41  and wash water pump  46  into the waste water holding tank  50 . The water pump  46  may now be turned off and the vacuum hose  41  stowed for transport. The concrete pump  25  is now ready for another job without first having to be moved to a disposal site for washout. 
         [0033]    The waste concrete  59  remaining in tub  35  (see  FIGS. 4A ,  4 B and  5 ) is then allowed to harden and, after hardening, removed from the tub and, in one mode, disposed of with the other solid discards from the building site. Advantageously, before the waste concrete  59  in tub  35  has set, a waste concrete partitioner  60  is utilized to form more manageable smaller and lighter blocks  65  of waste concrete. One embodiment of a waste concrete partitioner  60  is shown in  FIGS. 6A and 6B , formed by two center planar members  61  and two parallel orthogonal planar members  62 ,  63 . The partitioner  60  is pushed into the remaining fluid cement  59  in tub  35 . After the waste cement in tub  35  has hardened, it can be removed from the waste concrete tub  35  by turning the tub over. When, for example, the hardened waste concrete is struck by a heavy hammer, the partitioner  60  allows the waste concrete to split easily into nine smaller blocks  65  typically 8″ by 8″ and weighing typically no more than 25 lb. each so that each block can be thrown into an on-site waste pick-up for removal with other waste solids for easy handling and disposal. 
         [0034]    The blocks  65  may be also used as on-site filler matter or otherwise, 
         [0035]    The tub  35  and partitioner  60  are not limited to only forming blocks. The tub and partitioner can be shaped to provide a mold for forming a usable concrete structure such as a support pier or forming decorative objects. 
         [0036]    It is also not necessary to use the waste concrete partitioner  60  if the total contents of the tub  35  can be handled as one piece. The partitioner  60  may be constructed from inexpensive fibreboard, plastic or the like and may or may not be re-used. Tub  35  can be formed into any convenient shape and is not limited to the rectangular and cylindrical configurations shown in the drawings. The word “tub” has no particular meaning and is meant to cover any kind of appropriate receptacle for avoiding spillage by catching the waste concrete and wash water removed from hopper  34 . 
         [0037]    The washout water holding tank  50  is easily emptied when full, whenever or wherever it is convenient and environmentally appropriate. In some situations, the washout water holding tank  50  can be conveniently emptied into the hopper of a concrete truck  30  equipped with a vacuum pump (not shown). The tank liquid outlet fitting  151  (see  FIGS. 9  and  10 ) is connected to this vacuum pump. In this mode, the drain washout water tank is pumped into the input hopper of the concrete truck for re-use at the concrete yard. 
         [0038]    As described in more detail below and shown best in  FIGS. 8-12 , settled cement and sand sediment buildup in the tank  50  is easily removed by virtue of a downward sloping tank bottom and cleanout port  155 . 
         [0039]    The system can also serve as a water conservation system. Since the solids in tank  50  settle to the tapered bottom, the water on top is relatively free of particulate matter and can be pumped out and re-used, for example, for priming concrete pump hose  30 . 
       The Water-Solid Separator Unit 
       [0040]    The water-solid separator unit  40  is shown in detail in  FIGS. 13 and 14  and includes a cage formed by a top cover  75 , bottom cover  76 , and a cylindrical inner member  77  having a plurality of through hole openings  80  formed in its wall. A mesh  85  is located around the outside of member  77 . Mesh  85  serves as an aggregate strainer and is sized to prevent entry into the interior of separator  40  of solids large enough to clog or damage the hose  41 , wash water pump  46  or storage washout water tank  50 . By way of specific example, one embodiment of the separator  40  has an outer diameter of 4″, a height of 3.5″ and the mesh  85  is 1/16″, i.e. particles larger than 1/16″ will be prevented from entering vacuum hose  40 . 
         [0041]    Unit  40  further includes extension pipe  90  having one end  91  attached to threaded coupling  92  attached to the top cover member  75 . Extension pipe  90  extends into the interior of the cage formed by members  75 ,  76 , and  77 . Vacuum hose coupling  95  is attached to coupling  92  in communication with the extension pipe  90 . Coupling  95  is adapted to be connected to vacuum hose  41 . The distal end  93  of extension pipe  90  faces the bottom cover member  76  but with sufficient space between the end  91  and the bottom  76  so as to not interfere with the suction provided by vacuum hose  41  when the wash water pump  46  is activated. 
         [0042]    The embodiment of unit  40  illustrated is constructed to maintain evacuation of the waste water for tub  35  so long as some portion of the aggregate strainer mesh  85  remains above the waste concrete level  100 . Thus, as shown in  FIGS. 4A ,  4 B and  5 , the external part of the strainer  85  which is immersed into the waste concrete  100  will tend to block some inflow of water into the interior of the unit cage, namely that portion of the strainer mesh  85  submerged into the concrete solids  100 . However, water will continue to be evacuated even though the unit is totally submerged below the water level (see level  101  in  FIG. 4B ). This evacuation flow of water is provided by the extension pipe  90  attached to hose  41 . As shown in  FIGS. 4A and 4B , the extension pipe  90 , attached to the hose  41  allows the strainer to be partially submersed in concrete  100 , but with a significant surface exposed to air, since the water will flow into the strainer by gravity and the extension pipe distal end  91  being submersed in the water contained in unit  40 , will not be exposed to air thereby preserving vacuum within extension pipe  90  and hose  41  and enable unit  40  to continue sucking out the wash water within the cage of unit  40 . This is so even when the water level drops to level  102  (see  FIG. 4B ). 
       The Washout Water Holding Tank 
       [0043]    One embodiment of the washout water holding tank  50  is shown in the detailed drawings of  FIGS. 8-12 . The tank  50  includes inlet fitting  150  for attachment to hose  51  from wash water pump  46 . Tank  50  further includes water outlet fitting  151 . By way of specific example, one embodiment of tank  50  holds 50 gallons of liquid. 
         [0044]    The entire bottom of tank  50  is sloped advantageously to a large drain  155  (see  FIGS. 8-11 ) so that when drain  155  is opened, any solids small enough to pass through the mesh strainer  85  ( FIG. 14 ) will settle to the tank bottom and are easily cleaned out through drain. Cleanout of tank  40  is further facilitated by water tight cleanout port  160  which allows a water hose to be physically inserted into the tank  50  to flush out any sediment remaining after the drain  155  is opened. 
         [0045]    Vent  175  vents the tank  50  to outside air and maintains the air pressure within tank  50  at atmospheric pressure. Accordingly, the walls of tank  50  will not be subject to any excess air pressure when the tank is filling with washout water or is being drained of waste water. Therefore, the walls of tank  50  can be made inexpensively from plastic, metal, or other water tight material and do not need to be strong enough to support either a vacuum or air pressure. 
       The Washwater Pump 
       [0046]    Many different types of pumps may be used for the washwater pump  46 . One specific example of a useful pump is the Yamada Model ND P-25-BAN air powered double diaphragm pump. 
       Packaging the System Components 
       [0047]    In  FIG. 1 , the washwater holding tank  50  is attached below the bed of truck  27  and washwater pump  46  is located on trailer  26 . In  FIG. 2 , the washwater holding tank  50  and washwater pump  46  are both located on truck  27 . These locations are, by no means, the only locations for these components and the use of the system has substantial flexibility in locating these components. Thus, in other embodiments, the washwater pump  46  and holding tanks can be mounted together as a pre-packaged system for installation on a truck or trailer or separately mounted as suits the convenience of the user and the space availability for the components. 
       Concrete Truck Chute Washout 
       [0048]    A further advantageous mode of use of the concrete pump washout system is shown in  FIG. 7 . 
         [0049]    In normal operation, the concrete truck  32  is positioned such that its chute  33  will pour liquid concrete into the concrete pump hopper  34 . It is not unusual for a number of truck loads of concrete to be used on one job, so if the truck chute  33  is washed out into the pump hopper  34  after each load, the waste water  200  must be removed from the pump hopper or the next load of concrete delivered to the pump will be diluted. 
         [0050]    The water-solid separator unit  40  is mounted to the end of vacuum hose  41  connected to the vacuum end  45  of wash water pump  46 . The separator unit  40  is placed into hopper  35  and typically pushed partially into the concrete  205  in the concrete pump hopper  34 . The pressure end  47  of the water pump  46  is connected to output hose  210  and directed into the concrete truck hopper  215 . A pipe  220  with a hook on the exit end can be connected to output hose  210  and used to hang over the truck hopper  215  for easy access from the ground. The waste water  200  is then pumped from the pump hopper  34  into the truck hopper  215 . Once the water is substantially removed, the truck  32  can go back to the yard for the next job and the pump is ready for its next load. The concrete washed out of the chute  33  into hopper  34  will mix with any concrete left from the previous job and either be mixed with the next load of concrete poured into hopper  34  or be washed out of the hopper  34  at the end of the pumping operation in the manner described above. 
       CONCLUSION 
       [0051]    The above presents a description of the best mode contemplated for the concrete pump washout systems and methods in such full, clear, and exact terms as to enable any person skilled in the art to which it pertains to produce these systems and practice these methods. These apparatus and methods are, however, susceptible to modifications that are fully equivalent to the embodiment discussed above. Consequently, these apparatus and methods are not limited to the particular embodiments disclosed. On the contrary, these apparatus and methods cover all modifications coming within the spirit and scope of the present invention.