Abstract:
A solid chemical dissolver for making liquid solutions from solid chemicals packed in small containers is disclosed. The solutions are used for cleaning tanks, boilers, cooling towers and similar equipment internally. The dissolver has at least one bowl for receiving and holding one or more of the small containers of solid chemical. A spray nozzle aimed at the solid chemical directs fluid under pressure at the chemical to dissolve some of it and form a cleaning solution. A reservoir is provided to hold the solution prior to use, and a drain member leading away from the reservoir is provided for withdrawing the solution and using it to clean the tanks or other equipment. A fluid level detection switch assembly is disposed in the reservoir to control the amount of fluid from the nozzle and the level of the solution in the reservoir. Various embodiments of the invention are disclosed.

Description:
FIELD OF THE INVENTION 
     This invention relates to systems for dissolving solid chemical concentrates to make solutions for cleaning tanks, boilers, cooling towers and similar equipment internally. Mineral deposits and scale due to evaporation and corrosion are formed on the insides of the walls of such equipment during the time it is in service and must be removed. More particularly, this invention relates to a simplified mechanical system for dissolving solid concentrates and storing the resulting solutions in a reservoir in the quantities needed for circulation through the equipment to be cleaned. When the stored quantities are drawn off, a further supply of concentrate solution is readily made and obtained. 
     BACKGROUND OF THE INVENTION 
     Various kinds of apparatus for supplying concentrated chemical products in solutions to combat scale or corrosion have appeared recently. For example, in U.S. Pat. No. 6,105,638, issued Aug. 22, 2000, and in its predecessor, U.S. Pat. No. 5,853,034, issued Dec. 29, 1998, containers on which pierceable caps may be fastened are partly filled with concentrated chemicals. A diluent, such as water, is added in a sufficient amount to create a desired use dilution. The cap is placed on the container, and the container and its contents are agitated. Thereafter, the container is upended onto a dispenser with a piercing head. The head punctures the cap, forming an aperture in the container and enters to withdraw the use dilution for circulation in a cooling tower or the like. 
     A different apparatus is illustrated and described in U.S. Pat. No. 5,213,694, issued May 25, 1993. In the system shown in that patent, when make-up water is added to a cooling tower, a float valve in the tower controls the level of water in the tower. Chemical additives are added to the water entering the tank by having a vacuum valve draw them from a chemical holding tank. 
     Another system is illustrated and described in U.S. Pat. No. 6,418,958 B1, issued Jul. 16, 2002. That patent is directed to a chemical feed system which has spray nozzles directed upwardly into a pair of feed bowls into which solid chemicals have been poured. The bowls measure the conductivity of the chemicals which they dispense. When water is introduced into the bowls by the sprays, the bowls drain into a sump in which the conductivity of the solution is constantly monitored. The system is arranged to maintain a solution of constant conductivity in the sump, and when more water is needed in the sump to reduce conductivity, it is introduced by a separate piping system independently of the sprays so as to avoid contact with the chemicals. 
     The systems illustrated in these patents reveal numerous drawbacks, especially in the manner of introducing chemicals into their respective systems. The containers used to hold the chemicals in transit are often large and unwieldy, and when the chemicals are removed or drawn from them, spills and other handling accidents often occur. The present invention addresses these problems by providing equipment which is simply constructed, clearly organized, and easily accommodates small canisters of solid concentrates which are safe and convenient for an operator or a shipper to handle. Such containers are lightweight, compact, readily installed, easy to store and convenient to dispose of when they are empty. The new dissolver disclosed herein accommodates them readily and quickly, and it produces proper treatment solutions almost immediately when the containers are set in place. The solid concentrates which the equipment handles also produce large quantities of treatment solutions in a highly economical manner. 
     SUMMARY OF THE INVENTION 
     The present invention is embodied in a solid chemical dissolver unit which comprises at least one bowl for receiving and holding at least one container of solid chemical and for channeling a liquid solution containing the chemical to a reservoir as the solid chemical in the container is dissolved in a liquid spray. A spray nozzle for fluid under pressure is aimed at the solid chemical in the container to dissolve a portion of the chemical in the spray and form a solution containing the chemical in the bowl. A reservoir is provided for the dissolved chemical solution. A drain member leads out of the reservoir for withdrawing the dissolved chemical solution from the reservoir. There is also a fluid level detection switch assembly disposed in the reservoir controlling the amount of fluid from the nozzle and the level of dissolved chemical solution in the reservoir. 
     From the foregoing, and from what follows, it will be apparent that the present invention solves numerous problems which operators of tanks, boilers, cooling towers and similar equipment have had. 
     Accordingly, it is an object of this invention to provide a solid chemical dissolver which accepts small quantities of solid chemicals in containers which are easily handled by one person. 
     It is another object of this invention to provide a solid chemical dissolver which is easily loaded with a quantity of solid chemical without removing the chemical from its conventional container, such as the pail or jar in which it is shipped or stored. 
     It is a further object of this invention to provide a solid chemical dissolver which accepts small quantities of solid chemicals which can be handled without spills or other accidents which faulty handling can cause. 
     It is a further object of this invention to provide a bowl in which a small container, or group of small containers, which has or have been opened may be easily upended in the bowl and a solution obtained by spraying the solid chemical at an open end of a container. 
     Other objects and features of this invention will be apparent to those skilled in the art of making equipment for forming and dispensing solutions which combat corrosion and scale in equipment such as boilers and cooling towers from an examination of the following detailed description of preferred embodiments of this invention and of the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of one form of a solid chemical dissolver embodying the present invention illustrating a bowl and its associated elements for receiving a container of solid chemical and dissolving the solid chemical with a spray; 
     FIG. 2 is an elevational view of the solid chemical dissolver in FIG. 1; 
     FIG. 2A is an enlarged elevational view of an alternative form of a portion of the chemical dissolver in FIG. 2; 
     FIG. 3 is a schematic view of a system incorporating the form of solid chemical dissolver of FIG. 1 for circulating a solution containing the dissolved solid chemical in a cooling tower; 
     FIG. 4 is a perspective view of a second form of solid chemical dissolver embodying the present invention; 
     FIG. 5 is an elevational view of the solid chemical dissolver of FIG. 4; 
     FIG. 6 is a top view, in perspective, of the solid chemical dissolver of FIG.4; 
     FIG. 7 is an enlarged perspective view, partially broken away, of a portion of the solid chemical dissolver of FIG. 4; 
     FIG. 8 is a top plan view of a third form of solid chemical dissolver embodying the present invention; and 
     FIG. 9 is an elevational view of a fourth form of solid chemical dissolver embodying the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The preferred embodiments of this invention shown in the accompanying drawings will now be described, it being understood that the preferred forms are illustrative and that the invention described herein is embodied in the claims appended hereto. 
     The dissolver  10  illustrated in FIGS. 1 and 2 is arranged to receive a small pail  12  or similar container (such as a jar) of solid concentrated chemical. An example of such a container is a plastic pail weighing approximately twelve and one-half pounds, including contents. Other similar container sizes may be used. A bowl  14  mounted on a frame such as board  16  forms a receptacle for the solid concentrate container  12 . One convenient size for the board to be is about twenty-four inches square. Bowl  14  may be provided with a lid  18  as shown in FIGS. 1 and 2 if the container  12  is small enough to fit wholly inside the bowl. However, if the container is too tall, as container  12   a  is in FIG. 2A, or if no cover for the bowl is desired for some other reason, an open bowl  14   a  without a lid may be used. 
     If the solid concentrate pail or container  12  is received by a user with a lid or some other form of cover over the solid concentrate, that cover is removed before the concentrate is used in dissolver  10 . When such a cover is removed, and the solid concentrate exposed, the pail or container is inverted so that its open end, and the exposed solid concentrate, face downwardly. The open end of the pail or container is seated in the bowl near the bottom, which may be accomplished by wedging the rim edges  20  of the container at the container&#39;s open end against the inner walls of the bowl  12  near the bottom of the bowl, or by resting the rim edges  20   a  of the container  12   a  on a grate in the bottom of the bowl (not shown) or by a similar easily accomplished engagement which essentially involves a careful setting of the open end of the solid concentrate pail or container in the bowl. 
     A reservoir  24  is also mounted on board  16 , connected to the bottom  26  of bowl  14  by bowl discharge piping  28 . An identical connection is shown in FIG. 2A between bowl bottom  26   a  and discharge piping  28   a . A nozzle  30  for a fluid such as water under pressure, preferably disposed at about 120 degrees, is connected to the bottom  26  of the bowl  14  and aimed at the open surface of the solid concentrate in container  12 . When a spray from the nozzle  30  washes the face of the solid concentrate, the resulting solution drains downwardly through piping  28  into reservoir  24 . Toward the bottom of reservoir  24 , discharge piping  32  provides an outlet to drain the contents of the reservoir to a pump, shortly to be described. There is a valve  34  disposed in the discharge pipe  32  to close or open that pipe and let the reservoir  24  be drained. When the chemical solution is withdrawn from the reservoir, the pump circulates it to a cooling tower or similar equipment needing treatment (See FIG.  3 ). 
     Inside reservoir  24  there is a fluid level detection and control system which includes first and second float switches  36  and  38 , respectively, and also a high fluid level indicator system which includes float switch  40 . Float switch  38  controls fluid input to nozzle  30  and thus directs fluid to enter bowl  14 , as will be explained momentarily, while float switch  36  controls cutting off fluid input, which will also be explained momentarily. Float switch  40  overrides all other fluid input and directs such input to stop whenever the fluid level in the reservoir  24  gets too high. Float switch  40  also activates a warning light  48  to tell an operator that the fluid level in the reservoir has gotten too high. 
     A power input cord (not shown) is connected to the dissolver  10  at the input connector terminal  42 . Normally, a 120 volt power input brings local power to the site of the dissolver installation. However, in order to operate the relays and switches in the dissolver system, a  120  volt AC to  24  volt AC transformer and appropriate relays mounted in box  44  are connected to terminal  42 . An electrical control box  46  for the float switches  36 ,  38  and  40  is connected to the transformer box  44  and is preferably located as close as possible to the switch mechanisms which are in the reservoir. The control box  46  may also carry the high fluid level alarm, such as the light  48 , to provide a warning whenever fluid in the reservoir reaches an upper safety limit and requires attention. 
     Fluid input into dissolver  10  is provided through water supply piping  50 , which typically may be tipped with a three-eighths inch inlet copper tubing connector  52 . Immediately adjacent the inlet connector  52 , a Y-strainer  54  is provided to protect the dissolver system from extraneous foreign matter. A lower solenoid valve  56  is adjacent to strainer  54  and normally remains open while the dissolver is operating. In an emergency, however, this valve would close in order to stop water from entering the dissolver system. Above valve  56 , as seen in FIGS. 1 and 2, the supply piping  50  includes a pressure regulator  58  and a pressure gauge  60  for monitoring the incoming fluid. Normally, such fluid is fresh make-up water flowing at a minimum of 45 psi and at about 0.9 gallons per minute maximum flow. Thereafter, in line  50 , upper solenoid valve  62  is installed, connected to and controlled either by the lower level float control switch  38  which directs valve  62  to open and let water into the system, or by middle float switch  36  which directs valve  62  to close and prevent more water from coming into the system. In the unusual situation when a power loss occurs, upper solenoid valve  62  is closed in order to prevent the reservoir  24  from overflowing. Cables  64  and  66  connect the lower and upper solenoid valves, respectively, to the electrical control box  46 . 
     Tubing  68  continues the fluid input of piping  50  to its connection with nozzle  30 . In this manner a conduit is provided for a fluid under pressure to be sprayed against the solid chemical concentrate in the container  12 . A vacuum breaker  70  is installed in the piping  50  adjacent the upper solenoid  62  in order to avoid any fluid back-up in the line. 
     The contribution which dissolver  10  makes in a chemical treatment process may be seen in the cooling tower treatment system illustrated in FIG. 3. A supply of fresh water is schematically represented at  72 . The water brought in from the supply is led to the dissolver  10  through pipe  74 . A fluid supply pipe  50 , as described above, has a distal connective member  52  suitable for engaging the dissolver to a pipe such as  74 . A system control, illustrated at  76 , directs the input of fresh water to the dissolver  10  through line  78 . Control  76  also directs the withdrawal of chemical solution created by the dissolver  10 , by commands issued along line  80 , to a chemical pump  82 , the pump being connected to a discharge pipe  84  attached to a discharge piping member in dissolver  10  like piping  32 . 
     Arrows  86  illustrate that pump  82  circulates chemical treatment solution to cooling tower  88 . Then, after the solution is passed through the cooling tower  88 , it is directed by pump  90  through a pipe in the direction of arrows  92  for recirculation or, as shown by arrow  94 , for a withdrawal from the system, i.e., drained away at drain  96  and replaced by fresh water as directed by control  76 . 
     To install dissolver  10 , one may fasten it to a wall by using anchor screws (not shown) inserted into holes  98  in the corners of the frame  16 . Dissolver  10  should be mounted as close as possible to the chemical pump  82 . A user should provide a local shut-off valve in the water supply line leading to dissolver  10  (line  74  in FIG. 3) and use, preferably, three-eighths inch tubing to conveniently join into the inlet copper tubing connector  52 . Normally, also, a three-eighths inch tubing fitting  100  is provided at the outer end of discharge piping  32  near the bottom of reservoir  24  which will connect conventionally with the discharge pipe  84  leading to chemical pump  82 . 
     Assuming that the elements and sizes of parts just described have been adopted in assembling the board-mounted dissolver  10 , the net weight of the dissolver on the board is about twenty-three pounds. Assuming further that a twelve and one half pound plastic pail of solid chemical concentrate is placed in bowl  14  and that the system has been run using clean make-up water so that the reservoir  24  is full of liquid solution, the water and chemical concentrate pail add about nineteen pounds and bring the total weight of the board-mounted dissolver of the present invention to about forty to forty-five pounds in use. 
     When dissolver  10  is first turned on (with valve  34  set in the open position), both the upper solenoid valve  62  and the lower solenoid valve  56  open to let water (running at at least 45 psi) into the system through water supply piping  50 . The water runs through tubing  68  into nozzle  30  where it is sprayed against the solid chemical concentrate in the pail or container  12 . The spray form a solution with some of the chemical by dissolving it in the spray, and the solution thus formed drains through pipe  28  into the reservoir  24 . When the reservoir is filled to the point where the middle float switch is activated by the rising amount of fluid, switch  36  signals upper solenoid valve  62  to close, thereby shutting off further water until valve  62  is reactivated. 
     After the reservoir is filled, as described, pump  82  may be started so that it can draw chemical solution out of the reservoir through discharge pipe  32 . As the solution is pumped out, the level of the solution in the reservoir drops until the lower, low level float switch  38  is activated by the solution level and commands the upper solenoid valve  62  to reopen. As before, incoming water is sprayed through nozzle  30  at the solid chemical concentrate in the pail or container  12  and dissolves some of it. The cycle continues then to repeat itself. However, if the upper solenoid valve  62  should stick, or if it should begin to leak and allow fluid to pass through without a command to open, the resulting extra fluid in reservoir  24  would activate the high level float switch  40 , and that switch would send a command to lower solenoid valve  56  to close. No water would then be permitted to enter the system until the malfunction in the upper solenoid valve  62  was resolved. Notably, the connection between the high level float switch  40  and alarm light  48  would turn the light on in order to alert a system operator to the valve problem. Desirably, too, the upper solenoid valve  62  is programmed to close if a power outage should occur and thus prevent the reservoir from overflowing. 
     The embodiment of the present invention described above as dissolver  10  may be modified to adopt the form of dissolver  102  illustrated in FIGS. 4 through 7 which combines the bowl  14  and the reservoir  24  in a single container such as the can  104  illustrated in FIGS. 4 through 7. The can  104  may be as large as a small tank or vat. While the bowl  14  of dissolver  10  normally accepts a small pail  12  of solid concentrate, dissolver  102  is arranged to receive and dissolve an increased amount of solid concentrate from a larger pail or container (such as a jar)  106 . The bowl  108  of dissolver  102 , into which pail  106  is placed, is the upper portion of the can  104 , while the reservoir  110 , which stores the chemical concentrate solution as it is made and from which the chemical concentrate solution is withdrawn for treating equipment such as cooling towers, is in the lower portion of can  104 . Lower, middle and upper float switches  112 ,  114  and  116 , respectively, are positioned in the reservoir  110 . Discharge piping  118 , in which a PVC valve  120  is incorporated, depends from reservoir  110  for withdrawing the chemical concentrate solution. A frame  122  in the form of a stool supports can  104  and its associated piping, controls and contents. 
     A fluid inlet line  124 , which includes piping and valves governed by control box  126 , brings incoming fluid to nozzle  128  aimed at the solid concentrate in container  106 . As was the case with dissolver  10 , the nozzle  128  sprays the incoming fluid, normally fresh make-up water, at the face of the solid concentrate to dissolve it and form a solution. The solution thus formed collects in the reservoir portion of the can  104 . Middle float switch  114  and lower float switch  112  direct the turning on and turning off of incoming fluid by controlling upper solenoid valve  130 , and upper float switch  116  directs lower solenoid valve  132  to close the fluid inlet line  124  whenever the fluid level in the reservoir portion  110  of can  104  gets too high. Pressure regulator  134  and pressure gauge  136  monitor the fluid pressure in the fluid inlet line  124 . A Y-strainer  138  maintains the integrity of the incoming fluid. A vacuum breaker  140  is also included in the inlet line to prevent back-ups. 
     When the pail or jar or other container  106  is up-ended in can  104  so that its contents, the solid concentrate, face nozzle  128 , the pail&#39;s rim  142  rests on a grate  144  nested in the reservoir portion  110  of can  104 . In that position the bottom  146  of the pail faces upwardly. A plunger, rod  148 , is arranged with its lower end resting on the pail bottom. The upper end of the plunger  148 , as illustrated in FIGS. 6 and 7, is slideably mounted in a grommet  150  disposed in a lid  152  covering the upper end of can  104 . An electrical box  154  on top of lid  152  carries a switch  156  connected to the lower solenoid valve  132  through cable  158  and control box  126 . A trip member  160  on switch  156 , which is moveable to the dotted line position  162 , is normally disposed against the upper end or the plunger  148 , and usually set in the “on” position shown in solid lines in FIG. 7 . When plunger  148  is moved upwardly, as indicated by the two-way arrow  164  in FIG. 7, switch  156  is tripped to the “off” position by the upper end of the plunger raising the trip member  160  to its dotted line position  162 . When switch  156  is tripped in this manner, it commands the lower solenoid valve  132  to close and stop water from entering the system until the switch  156  is reset. The tripping of switch  156  to the “off” position also turns on a visual indicator, such as lamp  166 , to alert an operator to the fact that the dissolver system has been shut off. An electrical power input cord  168  supplies power to box  154  for both the switch  156  and the lamp  166 . The plunger  148  is moved to its dotted line position  148   a , shown in FIG. 7, in the following manner. When the pail  106  is first set into can  104 , ,it contains a quantity of solid chemical concentrate and assumes the solid line position shown at  106 . After the fluid spray from nozzle  128  has dissolved all of the concentrate and the pail is empty, the remaining fluid in the reservoir buoys the pail upwardly, causing its bottom to lift the plunger to position  148   a . 
     The embodiment of this invention shown in FIGS. 4 through 7 may be further modified, as shown in FIG. 8, to accommodate several smaller solid concentrate containers instead of the single container or pail  106 . In the embodiment shown in FIG. 8, can or tank  170  is divided into four compartments  172 ,  174 ,  176  and  178  by partitions  180  and  182 . Each compartment contains one of the up-ended containers or pails  184 ,  186 ,  188  and  190 . The pails initially contain a solid chemical concentrate and their rims rest on a quadrant of grate  192 . Each container is fed through its own solenoid valve and spray nozzle and is fitted with its own plunger. The plungers, which engage float switches  194 ,  196 ,  198  and  200  on lid  202 , are activated in the manner described above when their respective pails become empty. In this embodiment, as each of the pails becomes empty, its float switch transfers the flow of water to the nozzle servicing the next full container. Visual indicators, such as the lamps described above, are lit at each emptied container so that an operator can replace them with filled ones. Normally such replacements occur, in the four pail unit, when three containers are empty and the system is in the process of emptying the last one. 
     A further embodiment of this invention is shown in FIG.  9 . The arrangement and function of the dissolver components illustrated in this figure is very similar to the arrangement and function of the components in dissolver  10 . In the modification shown in FIG. 9, the bowls  204  and  206  are arranged side by side on a board  208 . Each bowl is served by a nozzle,  210  for bowl  204  and  212  for bowl  206 . Each bowl holds an inverted solid concentrate container into which the respective nozzles direct a spray. The bowls are operated in sequence and drain solution into discharge pipe  214  leading to reservoir  216 . Solution is drawn from the reservoir through discharge piping  218  for use in cleaning a cooling tower or similar equipment. Middle float switch  220  and lower float switch  222  regulate the solution level in the reservoir, and upper float switch  224  protects against overflow. A fluid inlet line (not shown) contains all of the components similar to line  50  except that there are two upper solenoid valves, one for nozzle  210  and one for nozzle  212 . The upper solenoid valves are interconnected and essentially operate in sequence, one after the other, to empty the pails of solid concentrate in the bowls served by their respective nozzles. 
     From all of the foregoing, it will be evident that although particular embodiments of the invention have been illustrated and described, nevertheless various modifications can be made without departing from the true spirit and scope of the invention. Accordingly, no limitation on the invention is intended by the foregoing descriptions of various embodiments, and the full breadth of the invention is intended to