Abstract:
A granule dishwashing apparatus with at least one removable granule collector and method of use. The dishwashing apparatus may include a treatment chamber, a tank, one or more granule collectors and one or more pumping devices. Soiled articles are placed in the treatment chamber to be washed with a mixture of liquid and granules that is sprayed at the articles under high pressure. The mixture falls toward the tank after impacting the articles, passing through the granule collector(s). A liquid only portion is separated from the mixture using the granule collector(s) so that the articles can be rinsed. At any point following a cleaning cycle, the granule collector(s) can be removed to add more granules and to simplify the cleaning of the apparatus. The granule collectors may be connected to actuators so that they can be placed in a release mode or a collect mode depending on the function desired.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a division of application Ser. No. 09/899,781, filed Jul. 5, 2001, now U.S. Pat. No. 6,609,960, which is a continuation of application Ser. No. 09/292,447, filed Apr. 15, 1999, now U.S. Pat. No. 6,280,301, which claims the benefit of Swedish patent applications SE 9801343, filed Apr. 17, 1998, and SE 9801836, filed May 26, 1998. This application expressly incorporates by reference the entirety of each of the above-mentioned applications as if fully set forth herein. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     REFERENCE TO A COMPACT DISK APPENDIX 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to a cleaning machine and, more specifically, to a dishwashing apparatus and method of use that utilizes a mixture of liquid and granules to clean soiled articles, and includes one or more granule collectors to separate the mixture. 
     Dishwashing machines, needed to handle high volume and heavily soiled articles, such as in a commercial setting, are well known in the art. It is common practice to mix small, hard particles, such as granules, with water and detergent to achieve an optimal cleaning mixture that is sprayed under high pressure against articles to be washed. Generally, the machines are equipped with a tank, spraying nozzles, and pumps. The liquid or liquid/granule combination is pumped to the nozzles where it is sprayed against articles to be cleaned. After the articles are cleaned, a separation cycle is necessary in order to remove any leftover residue or granules. Thus, a separation method for the granules is essential. 
     Many prior art references include machines functioning similarly to the above-described process, utilizing various separation methods. For example, U.S. Pat. No. 4,374,443 to Mosell discloses a cleaning machine that uses a liquid-permeable compartment or cassette which either separates or combines the cleaning liquid and granules. This liquid permeable compartment is located inside a liquid container and connects the bottom of a treatment chamber to the liquid container. The liquid permeable compartment communicates with a pump via a valve-controlled opening. Based upon whether the valve-controlled opening is open or closed, either cleaning liquid alone or a slurry of liquid and granules will be drawn by the pump through a suction chamber which is connected to the liquid container. Once the pump has drawn the liquid or the liquid/granule slurry, the fluid alone or slurry will be sprayed through nozzles located in the treatment chamber against goods to be cleaned. 
     In another patent issued to Mosell (U.S. Pat. No. 4,801,333), a cleaning machine is disclosed that separates granules by using two different levels for liquid and granules. A branch conduit is connected to a bottom outlet and a tank at a position above the surface of a bottom layer of granules below a liquid surface (the granules have a higher density than the liquid). The branch conduit has a float valve at an opening inside the tank and a closure valve between the bottom outlet and the position where the two conduits meet. When the closure valve is opened, the pump will draw from the tank through the bottom conduit, drawing liquid and granules to blast the soiled articles in a treatment chamber. When the closure valve is closed, the pump will draw liquid from the tank through the branch conduit and liquid only will be supplied for rinsing the cleaned articles. 
     U.S. Pat. No. 5,468,175 to Nilén discloses another way of separating granules in a cleaning machine. The granules are separated by a dividing wall with a pivoting portion at the wall base. The dividing wall separates the tank into two chambers, one with liquid only and the other with liquid and granules. The pivoting arm seals against the tank to prevent granules from passing when closed, and when opened allows granules to pass along with the liquid into the pump, to be recirculated through the system. A different type of separation system was also disclosed by Nilén in U.S. Pat. No. 5,601,480. In this design, separation of granules is done by a separation plate that extends some distance up from the bottom. This separates the tank into two chambers, a small, liquid only chamber and a larger liquid and granule chamber. A second perforated plate may also be attached to the top of the liquid chamber to insure that no granules pass through. Two pumps are required for this system, one connected to each chamber. Depending on the desired make-up of the substance to be sprayed (liquid only or a liquid/granule mixture), each pump is turned on independently. 
     In U.S. Pat. No. 5,667,431 to Mortin, yet another type of separation device is disclosed. The separation in this patent is done by separating the holding tank into two sections. The first section has a strainer at the bottom that allows the granules to pass into a conduit which is attached to a pump. If water gets too high in the first section it will spill over to the other section. Because the density of the granules is greater than the density of water, the overflow will theoretically contain liquid only. This second, liquid only section also has a conduit which is attached to a pump. Both pumps carry the liquid or liquid/granule mixture to a nozzle arrangement where they are sprayed against the articles to be cleaned. Alternatively, if the density of the granules is less than the water, a separate embodiment contemplates a system where the passage is at the bottom of the tank and the supply means is located in the upper portion. 
     Finally, U.S. Pat. No. 5,735,730 to Jonemo et al. discloses a dishwasher that uses a valve separation device to separate the granules from the liquid. The granule valve has a socket open at each end, and is associated with a bottom outlet. The socket is guided for vertical displacement between the upper position, with an opening at the lower end of the socket for drawing liquid with granules entrained therein by a pump from a treatment space at a lower level, and a lower position with the opening at the lower end of the socket closed for drawing liquid only by the pump from a higher level at the upper end of the socket. A projecting circumferential flange is provided on the socket below the upper end of the socket forming together with a cap that is located over the socket, a seal for preventing granules from being withdrawn along with the liquid. 
     While the prior art cleaning machines separate granules from liquids in a variety of ways, all are very difficult to clean at the end of a working shift. This can be largely attributed to the fact that the granules remain in the tank after the cleaning cycle, gravitating around the separation devices. Thus, cleaning the bottom of the tank becomes laborious. In view of the increasing demands from users for improved hygienic properties in the cleaning machines, a need exists to develop a cleaning machine which will collect the granules in an efficient manner so they can be removed for cleaning of the machine. In addition, removal of the granules is advantageous because the amount of granules can be monitored so that granules can be added when necessary to ensure that articles are consistently subjected to optimal cleaning conditions. 
     It is therefore an object of this invention to provide a granule dishwashing apparatus that is easy to clean at the end of a wash cycle. It is another object of this invention to provide a granule dishwashing apparatus that utilizes granule collectors to separate granules from liquid. It is still a further object of this invention to provide granule collectors in a granule dishwashing apparatus that are easy to install and remove. It is yet another object of this invention to provide a granule dishwashing apparatus that is easy to use and inexpensive to produce. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with the teachings of the present invention, a granule dishwashing apparatus with at least one removable granule collector and method of use is provided. The present invention encompasses a complete system for heavy-duty cleaning of articles, which is useful, for example, in a commercial environment. This system includes a treatment chamber for cleaning soiled articles, nozzles to spray liquid or a liquid/granule mixture against the articles, a pump or pumps to carry the liquid or liquid/granule mixture through the machine, and granule collectors to separate the granules from the liquid and to provide an easy way to remove the granules from the apparatus. 
     In a first embodiment of the invention, the granule dishwashing apparatus comprises one pump and piping system along with two granule collectors side-by-side, cleaning goods by using either a cleaning liquid entrained with granules (“the slurry”) or liquid only. This embodiment also includes a treatment chamber in which goods to be cleaned are stored in a washing rack. Nozzles in the treatment chamber spray a cleaning agent against the articles in the washing rack. The cleaning agent, which is pumped from a collection tank below the treatment chamber, may be either a cleaning fluid only or the slurry. 
     When the cleaning agent has impacted the goods, it forms a return flow which travels downward from the treatment chamber and is received by a tank below the chamber. The tank and treatment chamber form a single contiguous space within the dishwashing machine. Granule collectors are positioned side-by-side either in the tank or in the treatment chamber where they can receive the return flow. Assuming that the cleaning agent consists of the slurry, the granule collectors can either collect and separate the granules from the cleaning fluid or allow the granules to travel unimpeded with the cleaning liquid. Once the return flow has passed the granule collectors, it enters a conduit connected to the bottom of the tank. A pump draws the return flow through the conduit and pumps it back to the nozzles to be sprayed against the goods once again. 
     The granule collectors are discrete units, separate from the walls of the treatment chamber and the tank, and are removably and rotatably mounted in the machine. The granule collectors are coupled to actuators located outside of the machine. The actuators facilitate the two modes of operation for the granule collectors: collection and release. In the collection mode, the granule collectors are positioned by the actuators to “catch” the return flow in order to separate and collect the granules from the slurry. By catching the granules, the collectors allow the cleaning liquid alone to pass to the bottom of the tank and to be drawn by the pump and ejected through the nozzles. When the collectors are in the release mode, they do not catch the return flow. Thus, the return flow travels directly to the bottom of the tank and can be drawn by the pump through the conduit. In addition, in the release mode, granules previously collected by the collectors will be reintroduced to the return flow. 
     The granule collectors of the dishwashing machine allow the machine to be operated using a liquid only cleaning agent. This is advantageous for several reasons. First, for lightly soiled goods, a liquid only cycle may be desired. The collectors ensure that only liquid is ejected by the nozzles and circulated through the system. Second, at the end of the day, it is highly desirable to clean the dishwashing machine. Collection of the granules by way of the granule collectors greatly facilitates the cleaning task. Third, the granule collectors enable the operator to quickly and easily monitor the amount of granules remaining in the cleaning machine. A visual inspection of the granules captured in the collectors enables the operator to readily determine if there are sufficient granules or whether more granules should be added to the machine. Because the granule collectors are removable, this task can be accomplished quickly and efficiently. 
     In the preferred embodiment, the granule collector is formed of a basket having a bottom, side walls and end walls. Some or all of the walls of the collectors may be perforated. If a collector is in the collection mode and its walls are perforated, the liquid in the return flow passes through the perforations in the walls. Alternatively, if the walls are not perforated, the liquid initially collects in the collector, but when the volume of the liquid exceeds that of the collector, the liquid simply overflows the rims of the collector. The release mode for the collectors involves the rotation of the granule collectors onto their sides so that the return flow from the treatment chamber mostly bypasses them and travels unimpeded to the conduit at the bottom of the tank. 
     A second embodiment of the invention is also a cleaning machine that cleans goods by using a cleaning agent, which may be either a cleaning liquid entrained with granules (“a slurry”) or fluid only. However, in the second embodiment, there are two pumps utilized and the granule collection process involves only one collector. Moreover, the second machine can be smaller, for less voluminous uses, than the first. The second embodiment, like the first, includes a treatment chamber in which goods to be cleaned are stored in a washing rack. Nozzles in the treatment chamber spray the cleaning agent against the goods in the washing rack, and the cleaning agent is stored in and pumped from a collection tank located below the treatment chamber. When the cleaning agent has impacted the goods, it forms a return flow which travels downward from the treatment chamber and is received by the collection tank. The tank and treatment chamber form a single contiguous space within the dishwashing machine. 
     Assuming that the return flow is a slurry of fluid and granules, this embodiment utilizes a removable, basket-like granule collector to collect and separate granules from the cleaning fluid. During the machine&#39;s operation, however, the collector is stationary; that is, the device is always in a granule collection mode. The collector of the machine is located near the bottom of the collection tank and has perforated walls that permit liquid in the return flow to pass through them. Because the granule collector sits above the bottom of the tank, the collector segregates a portion of the tank below it. The portion of the collection tank below the granule collector contains cleaning fluid only and is thus granule-free. The bottom of the collector has a hole through which a primary conduit extends upwards into the collector and a deflector is located above this hole. When the collector is correctly positioned in the collection tank, the primary conduit extends upward through the hole in the bottom of the collector and terminates below the deflector. The deflector prevents granules in the return flow from falling directly into the primary conduit and displaces them to the bottom or sides of the granule collector. 
     The primary conduit is connected to a primary pump which in turn is connected to a primary set of nozzles in the treatment chamber. When the goods are to be cleaned with a slurry, the primary pump is activated, drawing granules from the granule collector together with cleaning liquid through the primary conduit in the tank. The primary pump discharges this slurry against the goods in the treatment chamber. The collector catches the return flow, filtering and collecting granules from the flow, and permitting liquid to pass through the perforations in its walls and collect in the tank. 
     When cleaning fluid alone is to be discharged against the goods, the primary pump system is disabled, and a secondary pump system which includes a secondary set of nozzles, pump and conduit is employed. A secondary conduit is connected to the portion of the tank below the granule collector. A secondary pump is connected to the secondary conduit as well as to a secondary set of nozzles in the treatment chamber. When the secondary pump is activated, it withdraws liquid only from the tank below the granule collector and sprays the fluid through the secondary nozzles against the goods stored in the treatment chamber. 
     A more complete understanding of the granule dishwashing technology of the present invention will be afforded to those skilled in the art, as well as a realization of additional advantages and objects thereof, by a consideration of the following detailed description of the preferred embodiments. Reference will be made to the appended sheets of drawings that will first be described briefly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1 . is a front perspective view of a first embodiment of the present invention with granule collectors in a closed position. 
         FIG. 2  is identical to  FIG. 1  with the exception that the granule collectors are in an open position. 
         FIG. 3  is a schematic side view of a variation of the granule collectors in an open position. 
         FIG. 4  is a schematic side view of the granule collectors in  FIG. 3  in a closed position. 
         FIG. 5  is a schematic side view of a second variation of the granule collectors in an open position. 
         FIG. 6  is a schematic side view of the granule collectors in  FIG. 5  in a closed position. 
         FIG. 7  is a sectional view of a second embodiment of the present invention. 
         FIG. 8  is a perspective view of the device according to  FIG. 7 . 
         FIG. 9  is a sectional view of a variation of the device according to  FIG. 7 . 
         FIG. 10  is a perspective view of the device in  FIG. 9 . 
         FIG. 11  is a sectional view of a second variation of the device according to  FIG. 7 . 
         FIG. 12  is a perspective view of the device in  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description should be read with reference to the drawings, in which like elements in different drawings are identically numbered. The drawings, which are not necessarily to scale, depict selected preferred embodiments and are not intended to limit the scope of the invention. The detailed description illustrates by way of example, not by way of limitation, the principles of the invention. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what is presently believed to be the best mode of carrying out the invention. 
     The present invention satisfies the need for a granule cleaning machine in which the granules are removable for cleaning and counting purposes. This is accomplished by the granule dishwashing apparatus of the present invention which utilizes removable granule collectors to quickly and easily remove granules at the end of a cleaning cycle so that the machine can be cleaned and additional granules can be added for consistency. 
     Referring now to  FIG. 1 , a first embodiment of the granule dishwashing apparatus  10  is shown. Dishwashing apparatus  10  consists primarily of a treatment chamber  20 , a tank  30  located below the treatment chamber  20 , and a conduit  50  that exteriorly connects the tank  30  to the treatment chamber  20 . The treatment chamber  20  contains washing rack  22  where soiled articles  24  are hung or supported in some manner to be cleaned. Numerous nozzles  26  are coupled to discharge pipe  28 . Discharge pipe  28  wraps a portion of the way around washing rack  22  so that nozzles  26  point in a direction facing articles  24 . Discharge pipe  28  as well as nozzles  26  are of sufficient size so that both liquid and granules can pass at an accelerated rate. Below treatment chamber  20 , tank  30  is positioned to funnel all of the liquid and granule mixture that has impacted articles  24 , i.e. the return flow, toward tank outlet  32 . Treatment chamber  20  and tank  30  flow continuously into one another. 
     Granule collectors  40  are disposed between washing rack  22  and tank outlet  32 . The granule collectors  40  can be disposed within tank  30  or near the bottom of treatment chamber  20 . Moreover, any number of granule collectors  40  can be assembled inside of tank  30 . One can envision a configuration involving multi-tiered collectors or numerous collectors on one level to substantially cover the surface area of the portion of the machine in which they sit. As shown in  FIG. 1 , however, two granule collectors are located in tank  30 . Granule collectors  40  are positioned side-by-side inside of tank  30  so that the majority of the return flow passes through the collectors  40  before continuing downward to the tank outlet  32 . Each granule collector  40 , as shown in  FIG. 1 , includes two side walls  44 , a bottom  46 , and two end walls  48 . As shown in  FIG. 1 , the side walls  44  have perforations  45  that are sized to restrict the passage of the granules, but allow the passage of liquid (in other embodiments, the bottom and end walls could also be perforated). Alternatively, the granule collectors  40  could be constructed with no perforations so that as the return flow would fall into the collectors  40 , the liquid would spill over the sides as the granules remained inside due to the greater density of the granules. 
     In either case, as shown in  FIG. 1 , the granule collectors are trapezoidal in shape with an open top side to allow flow of the mixture into the granule collectors  40 . The granule collectors  40  are mounted on shafts  42  which can be externally manipulated by various types of actuators (not shown), including those which are electrically and hydraulically powered. The actuators rotate the granule collectors  40  between different positions depending on the function desired. In the open position, as shown in  FIG. 2 , the granule collectors  40  are in a release mode and are turned sideways by the actuators so that the open portions of the collectors  40  are facing to the side of tank  30 . In this position, granules are allowed to pass by the collectors  40  without impedance to the tank outlet  32 . In the closed position, shown in  FIG. 1 , the granule collectors  40  are in a collect mode wherein a substantial amount of the return flow passes through the collectors  40  before continuing down toward tank outlet  32 . 
     The liquid portion of the mixture leaks through perforations  45 , leaving the granules inside of the collectors  40 . After several washing cycles, most of the granules are collected by the granule collectors  40 . The granule collectors  40  are removably mounted in the dishwashing apparatus  10  so that they are easily removed from the tank  30 . As seen in  FIGS. 1 and 2 , the granule collectors  40  are coupled to shafts  42  and are removable from the shafts at the end of a cleaning cycle. Alternatively, it is possible to envision a configuration in which a shaft portion is a part of the granule collector. In this alternate configuration, the shaft of the granule collector could fit into a hole in the back of the tank  30  and snap into a clutch assembly on the front of the tank, attached to the actuator. Once the collectors  40  are removed, the dishwashing apparatus  10  can be cleaned and those granules that were lost due to erosion can be replaced. 
     Directly coupled to the tank outlet  32  is a return flow conduit  50 . This conduit  50  is the means by which the return flow is sent back to the nozzles  26  to be re-circulated through the system. Return flow conduit  50  consists of a lower conduit  52 , which receives the return flow from the tank, and an upper conduit  54 , which transports the return flow to the discharge pipe  28 . Connecting the lower conduit  52  to the upper conduit  54  is pump  60  which acts to pull the return flow from the lower conduit  52 , transferring it to upper conduit  54  at an accelerated rate for spraying through nozzles  26 . 
       FIG. 3  shows a variation of the granule collectors to be used in dishwashing apparatus  10 . Granule collectors  80  are shown in the open position, or release mode. In this embodiment, two opposing side walls  84  of the granule collectors  80  are pivotally arranged on shaft  82 . The side walls  84  are formed with perforations  85 , which restrict the passage of granules, but permit passage of liquid. Granule collectors  80  also have a rear gable wall  86  and an opposing front gable wall (not shown). The granule collectors  80  in  FIG. 3  allow passage of the liquid and granule mixture without impedance.  FIG. 4  shows the granule collectors  80  of  FIG. 3  in the closed position, or collect mode. By pivoting the side walls  84  together to form a V, as indicated by arrows  87 , a basket-like structure is created consisting of two side walls  84 , a rear gable end  86  and an opposing front gable end. The granules are accumulated inside granule collectors  80  in this configuration, while return flow liquid is allowed to seep through perforations  85 . As in the embodiment shown in  FIG. 1 , granule collectors  80  are also coupled to actuators for positioning in the release mode or collect mode. In addition, they are easily removable from the dishwashing apparatus  10 . 
     Both  FIGS. 3 and 4  also show a flow director  70 , which is made of a coarse screen or similar device, that is used to protect the granule collectors  80  from a direct impact of the return flow. This may become necessary due to the vigorous nature of the return flow which could force already collected granules out of the granule collectors  80 . The flow director  70  has a plurality of granule openings  72 . The size and location of the granule openings  72  will allow granules to pass through the flow director  70  and into the granule collectors  80 . Thus, the granule collectors  80  will be filled with granules faster and granules will not be washed away. 
       FIG. 5  illustrates a second variation of the granule collectors to be used in dishwashing apparatus  10 . Granule collectors  90  are shown in the open position, or release mode. In this embodiment, granule collectors  90  are trapezoidal in shape and are disposed in treatment chamber  20  as opposed to tank  30 . Granule collectors  90  consist of side walls  94 , rear gable end  96 , front gable end (not shown) and a pivotable bottom  98 . The bottom  98  is pivoted between open and closed positions through the use of pivot pin  92 . An actuator (not shown) is attached to pivot pin  92  to open and close granule collector  90 .  FIG. 6  shows the granule collectors  90  of  FIG. 5  in a closed position. The bottom  98  is pivoted in the direction shown by arrows  97 . Once in the closed position, or collect mode, the granules will be collected inside of the granule collectors  90  as the liquid either overflows and spills out of the top, or seeps through perforations provided in side walls  94 . 
     It should be noted that it is not necessary to direct the total return flow into the granule collectors in the first embodiment. Although this would accelerate the separation process, the present invention provides a satisfactory result even if only some fraction of the return flow actually passes through the granule collectors. The reason for this is that the main pumping device  60  circulates the total tank volume so many times during a normal separation period that practically all of the granules will be collected. Moreover, the time cycle used depends on the nature of the articles to be cleaned. For instance, a longer time cycle of 6 minutes, consisting of washing with a mixture of liquid (water and detergent) and granules for 4 minutes, separating granules from the water for 1 minute and rinsing with clean hot water for 1 minute, would be used for articles that are heavily soiled. On the other hand, a shorter cycle of 3 minutes, wherein a mixture of liquid and granules are used to wash for 1.5 minutes, separating occurs for 0.75 minutes, and rinsing finishes the cycle for 0.75 minutes, is used for lightly soiled articles. Also, the hot water used for the rinsing cycle can be mixed with a rinse agent that reduces surface tension and thus prevents marks from drying drops and generally speeds up uniform drying. 
     A second embodiment of the present invention is illustrated in  FIGS. 7–12 , contrasting with the first embodiment in the fact that two separate conduits are used along with two pumps and two discharge pipes. Also, only one granule collector is used as opposed to multiple collectors as in the first embodiment. Moreover, the second embodiment can be a smaller machine for applications that require less frequent or less voluminous use. The smaller machine can also have two settings, one for delicate articles such as glass and porcelain, and one for harder to clean articles such as pots and pans. In  FIGS. 7 and 8 , dishwashing apparatus  110  is shown, consisting of a treatment chamber  120 , a tank  130 , granule collector  140 , primary conduit  150  and secondary conduit  170 . The treatment chamber  120  contains washing rack  122  where soiled articles  124  are hung or attached in some manner to be cleaned. Two discharge pipes  128  and  129  are positioned along the outside of washing rack  22 . Primary discharge pipe  128 , with nozzles  126  attached thereto and facing the articles  124  on washing rack  122 , is equipped to handle a mixture of granules and liquid for the cleaning sequences. Secondary discharge pipe  129 , on the other hand, is smaller in diameter, as are its nozzles  127 , and is used for the spraying of liquid only. Tank  130  is located below treatment chamber  120  and acts to funnel the return flow through granule collector  140 , located near the bottom of tank  130 , for passage through primary conduit  150 . As in the first embodiment described above, treatment chamber  120  and tank  130  form a single contiguous space. 
     Granule collector  140  is disposed near the bottom of tank  130 , resting on ledge  134  such that a space  132  is created below it. This alignment makes removal of granule collector  140  from dishwashing apparatus  110  fast and easy at the end of a cleaning cycle. Granule collector  140  is trapezoidal in shape and forms a basket-like structure such that a top side  144  that faces treatment chamber  120  is open for receiving the return flow and covers substantially all of the surface area of the portion of the tank in which it lies. One or all of the sides of granule collector  140  can be perforated with perforations  142  to allow the passage of liquid. Perforations  142  are sufficiently small to prevent the passage of granules, but are large enough to allow the passage of liquid. A primary conduit  150  runs through space  132  and connects to the bottom of granule collector  140  at hole  146 . The hole  146  is close enough in diameter to conduit  150  so that granules can not pass there between. A deflector  148  is disposed directly above the hole  146  in the bottom of granule collector  140  to prevent granules from entering conduit  150  when dishwashing apparatus  110  is not in operation and when granule collector  140  is lifted out of dishwashing apparatus  110 . 
     Primary conduit  150  links tank  130  with treatment chamber  120  and consists of lower conduit  152  and upper conduit  154 . Lower conduit  152  is coupled to the bottom of granule collector  140  on one end and to an inlet for primary pumping device  160  on the other end. Upper conduit  154  is connected to an outlet of primary pumping device  160  and treatment chamber  120 . When dishwashing apparatus  110  is in operation, primary conduit  150  along with primary pumping device  160  transport return flow in the form of a slurry from the granule collector  140  to the discharge pipe  128  for reuse. A secondary conduit  170  is also used in this embodiment, to transfer liquid only from the tank  130  to the treatment chamber  120  to flush any remaining granules off of articles  124  at the end of a cleaning cycle. Secondary conduit consists of a secondary lower conduit  172  and a secondary upper conduit  174 , connected by a secondary pumping device  180 , which can be much smaller than the primary pumping device  160  because the liquid only return is much less voluminous than the return flow running through primary conduit  150 . Secondary lower conduit  172  takes the liquid that seeps through the perforations  142  of granule collector  140  from space  132  below granule collector  140  to secondary pumping device  170 . From there, the liquid is pumped through secondary upper conduit  174  to a secondary discharge pipe  129 . 
       FIGS. 9 and 10  illustrate a variation of dishwashing apparatus  110 . In this design, a suction conduit  156  takes the place of lower conduit  152  of the previous design. Suction conduit  156  feeds into granule collector  140  through top side  144  so that the initial direction of the return flow is upwards. Thus, the deflector  148  of the previous design is not necessary because there is no danger of granules falling into suction conduit  156  at the end of a cleaning cycle. Suction conduit  156  also contains a coupling or joint  157  so that the lower portion of suction conduit  156  can be either removed or swung out of the way for easy removal of granule collector  140 . Upper conduit  158  is also different from the design shown in  FIGS. 7 and 8  in that it is shorter in length.  FIGS. 11 and 12  show a second variation of dishwashing apparatus  110  similar to the first variation except that instead of secondary conduit  172  connecting to the bottom of tank  130  at space  132 , liquid is withdrawn from the top of tank  130  through a sieve  177  which is attached to secondary lower conduit  176 . The positioning of sieve  177  is such that removal of granule collector  140  is still possible without removal of other components. Secondary upper conduit  178  in  FIGS. 11 and 12  takes the place of secondary upper conduit  174  of  FIGS. 7–10 , but has the same function. 
     Having thus described preferred embodiments of the granule dishwashing apparatus, it should be apparent to those skilled in the art that certain advantages of the within system have been achieved. It should also be appreciated that various modifications, adaptations, and alternative embodiments thereof may be made within the scope and spirit of the present invention. For example, while one and two collector systems have been illustrated, it should be apparent that the inventive concepts described above would be equally applicable to three or more collector systems. The invention is further defined by the following claims.