Abstract:
A wet exhaust processing system including an exhaust separator having a lower water containing portion and a wet exhaust inlet and a separated exhaust outlet above the water. An overflow pipe controls the upper lever of the water in the separator and a pump connected to the lower portion pumps the water therefrom to a filtering device. A sensing and control arrangement controls the operation of the pump and thereby the level of the water in the lower portion

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1) Field of the Invention  
           [0002]    This invention relates to wet exhaust processing systems for the exhaust from diesel engines generally and more specifically to such a system which insures that the effluent water discharged therefrom meets or exceeds current regulations as to the concentration of particulate matter, petroleum hydrocarbons (free oils) and petroleum byproducts in such discharge, and which system also is effective in capturing and thereby limiting particulate matter in the gaseous discharge from the system.  
           [0003]    2) Description of the Prior Art  
           [0004]    Wet exhausts for diesel engines are well known in the prior art, particularly in marine applications, as marine vessel environments require that the very hot diesel exhaust gases be cooled and water injection into the exhaust stream from the engine is a well known and convenient way of performing such cooling. However most prior art systems to provide such water cooling result in the discharge from the vessel of water which is contaminated with combustion byproducts from the engine, such as petroleum by products, petroleum hydrocarbons, and particulate matter. Before the enactment of regulations controlling the discharge of such materials from vessels, little was done to insure that such contaminants were not discharged. However, the development of a significant body of information on the effect of such contaminants on the environment have shown that petroleum hydrocarbons, especially free oils, tend to attach themselves to suspended particles and sediment, and particulate matter tends to settle into the bottom sediment as well. Since they can stay in the bottom sediment for years, they can be ingested by marine dwelling organisms. High concentrations of contaminants are found in marinas, and it appears that vessels at dockside, while running their diesel power generators and air conditioning equipment, are a significant contributor to such problems. Most marine diesel application installations in use today utilize a separator of one kind or another to remove the water from the exhaust gasses. This water is then discharged overboard along with any contaminants contained therein. A marine engine exhaust system which can remove such contaminants from the exhaust is shown in U.S. Pat. No. 5,980,344 to George F. Widmann, which is assigned to the same assignee as the instant application, and utilizes a first chamber into which the contaminated exhaust is discharged, the surface oils and particulate matters on the surface of the water in this container are then drawn off by a timed vacuum pump to a second container wherein the floating oils and particulate matter is retained and chemically digested to be later disposed. Non-floating contaminants, both oil and particulate, are not removed from the water in the first container and are never further processed by this device. The vacuum pump is not responsive to the water level in the first chamber, but is run by a timer. The water from the second container (which water still contains non floating contaminants) is then pumped to a third container containing filtration devices and the filtered water therefrom discharged overboard. While this device can operate satisfactorily when the vessel is stationary or at below planing speeds, it requires two containers and two steps, a digesting step and a filtering step, to remove the contaminate matter from the exhaust after the contaminated water has been removed from the exhaust in the first chamber, and the first chamber only functions as a separator when the vessel is stationary or moving below planing speeds, for once the vessel is on plane, the exhaust cooling water and the contaminated exhaust gasses are swept directly out of the boat hull through an opening in the bottom of the hull and the water from the exhaust cooling never reaches a level where it can be drawn off to the second or third container.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention simplifies the above prior art and provides improved operation by providing a system with a reduced number of structural components and yet one which will not only operate when the vessel is stationary but also, if desired, when operating at any speed, including full speed, and which utilizes the oil in the water to assist the filters in removing particulate matter. To that end, a separating chamber is provided which separates the water and the contaminates from the exhaust. A pump is provided to transport the water from the scrubber to the filter housing wherein the water is filtered and the clean effluent from the filters can be discharged overboard. A measuring and controlling system is provided to measure the level of the water in the scrubber and control the operation of the pump, and an overflow pipe that will dump water from the system in the event of pump failure or if the operator decides to bypass the filtration system in order to conserve filters, such as during passage at open ocean, or at such time that the device is shut down for repairs or service, such as changing filters. By keeping the oil along with the particulate matter in the water until it reaches the filter, the oil aids in the filtration process by assisting in the entrapment of the particulate matter in the filter. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    [0006]FIG. 1 is a front elevational view, partially in section and partially diagrammatic, of a system according to this invention;  
         [0007]    [0007]FIG. 2 is a plan view of the scrubber of FIG. 1;  
         [0008]    [0008]FIG. 3 is a side view of the overflow tube of the scrubber of FIG. 1; and  
         [0009]    [0009]FIG. 4 is a view like FIG. 1 of a system with a different scrubber. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0010]    Referring now to the drawings, and more particularly FIGS. 1, 2 and  3 , a wet exhaust processing system is shown generally at  10  and includes a separating device in the form of a scrubber  12 , a variable speed pump  14 , a filter section  16  and a control system  18  for controlling the operation of the pump  14 . The scrubber  12  is encased in a cylindrical housing  20  having a top cap  21  and a bottom end cap  22 . A wet exhaust pipe from a diesel engine is shown at  24 , which pipe enters the scrubber  12  through a central opening in the top cap  2   1 , and extends downwardly into the scrubber to terminate in a closed lower end  26 . Water  27 , with a desired water level  28 , is contained in lower portion or sump  29  of the scrubber  12 ., and the portion of the pipe  24  below the water level  28  is provided with a plurality of exhaust openings  30  spaced both vertically and circumferentially on the pipe  24 . Contaminated exhaust enters the scrubber  12  from the pipe  24  through the openings  30  below the level  28  of the water  27  within the scrubber so that the water  27  scrubs the contaminants from the exhaust and the contaminant are disbursed throughout the water. After the “scrubbed” exhaust leaves the water  27 , it is passes from the scrubber  12  through an effluent pipe  32  , shown in FIG. 2, which pipe exits the scrubber through the end cap  21 .  
         [0011]    Two devices control the upper extent of the water level  28  in the sump  29 . One such device is an overflow pipe  34 , which pipe is confluent with a standpipe  36 , which is supported at its upper end in the end cap  21 , and has its open lower end  37  displaced slightly above the bottom end cap  22 . An air vented end cap  38  is disposed on the top of the standpipe  36 , whereby water can enter the standpipe  36  through its open lower end  37  and when the level therein exceeds the level of the overflow pipe  34 , the excess will be discharged from the scrubber  12 . The second device is the pump  14  with its control system  18 .  
         [0012]    More particularly, the housing  20  of the scrubber  12  is confluently provided with a nipple  40  which exits the housing  20  slightly above the bottom end cap  22 . Confluent with the nipple  40  is a pipe  42  which extends to and supplies the intake of the pump  14 , which, in turn, at its output end, is confluently connected to the housing of the filter  16  by a pipe  44 . The housing has confluently connected thereto a discharge pipe  46 , whereby filtered water can flow and be discharged from the vessel. The pump  14  is sized according to the specifics of the particular vessel application. Information which is collected is water flow in G.P.M. , total length of pipe run, length of all up and down pipes, fittings and turnings in the pipe run, depth of overboard water outlet beneath the vessel&#39;s water line, diameter of all nozzles in the pipe run. These are given to the pump supplier that calculates the size pump required to overcome the calculated “head pressure” of the installation based on standard hydraulic engineering calculations for friction loss in pipes and fittings, and still pump the required G.P.M. against maximum pressure of clogged filters. For example, a generator powered by a Cat 3412 engine with a 40 foot pipe run required a model AMPCO ZC2-6.75-30G36BJM-50 pump from Delco Pump with a 7.5 hp 50 Hz motor. The filter housing  16  contains one or more filter elements  48 , which elements that have operated satisfactorily in this system can be obtained from Parker Hannifin Corporation under the model name of “Eco-filters”.  
         [0013]    The control system  18  includes a water level sensor  50  and a control unit  52  for controlling the operation of the pump  14 . A water level sensor which has been found to operate satisfactorily for this invention is a Superox(R) Model SM956A-130600s Ultra Sonic (analogue output) sensor. This sensor  50  is mounted in the top of a “still well”, which is a vertically mounted pipe  54 , open at its bottom end  56  and tightly and closely secured at its top end  58  in an opening in the top cap 2 l of the scrubber  12 . The pick-up end of the sensor  50  is directed downwardly, and the still well  54  provides a surface level reading for the water  27  in the scrubber by the sensor  50  which is not disturbed by the violent action of the exhaust gasses within the confines of the scrubber. The mounting between the sensor  50  and the pipe  54  contains a small vent opening  60  so that the level within the still well is not prevented from fluctuating as necessary to indicate the water level within the remainder of the scrubber  12 . A control unit  52  which has been found to work satisfactorily is Baldor series 15H Inverter Control unit operated in the Process Operating Mode. Baldor inverters are available from any Baldor dealer worldwide, applicant obtained his from A.A. Electric Corp. in Clearwater, Fla. The output from the sensor  50  is connected to the Baldor control unit  52  by a four conductor cable  62  and the Baldor unit is connected to a source of power  64  which includes 24 volt DC and 340 volt three phase AC. The output from the Baldor unit  52  is connected by a line  66  to the power input of the pump  14  The analogue output from the sensor  50  varies directly proportional to the water level in the still well  54  relative to the adjustable analogue span limits of the sensor. When the water level  28  is close to or at the near span limit but farther than the dead band, the sensor output is 20 mA and the pump  14  should be running at maximum RPM. When the water level sinks to or below the far limit, the output is 4 mA and the pump  14  should not be running. The parameters of the output from the sensor  50  are adjusted so that the water level  28  of the water  27  under normal operating conditions, does not vent through the overflow pipe  34 .  
         [0014]    While the separating device in the form of the scrubber  12  disclosed above in FIGS.  1 - 3  was conceived specifically for the system of this invention, the system will work almost as well with modified conventional separator  70  as seen in the exhaust system  10 A shown in FIG. 4. The separator  70 , which typifies a conventional separator, includes an enclosed container  72  with a wet exhaust gas inlet  74  entering the upper right side thereof An upper exhaust exit to a stack on the vessel is shown at  76  exiting the container  72  from the enclosed top  78  thereof, and a lower exhaust  80 , which contains a closing valve  82 , exits from the enclosed bottom  86  and extends to and is discharged out the side of the hull above the water line. A nipple  84 , confluent with the inside of the container  72  immediately above the enclosed bottom  86 , as conventionally installed, was connected directly to an overboard drain, and water from the wet exhaust that did fall out of the exhaust gasses upon entering the separator  70  from the inlet  74 , passed through a perforated plate  88 , and then out of the separator and overboard through the nipple  84  and the overboard drain (not shown). For the purpose of altering this conventional separator to work in this invention, a pipe  90  was confluently connected to the nipple  84  and from the latter to a pump  14 A, which is the same as the pump  14  of the embodiment of FIGS.  1 - 3 .  
         [0015]    A second modification was the addition of a standpipe in the form of an overflow pipe  92  to approximately just below the perforated plate  88 , for draining the water from the container at such times that the pump  90  was not operational. A third modification was the addition of a still well  94  comprised of an elbow  95  confluent with the inside of the container  72  immediately above the bottom thereof, and an upright pipe  96  extending upwardly from the elbow. A sensor  98  is disposed in the top of the pipe  96 , and a cable  62 A connects the sensor to a control unit  52 A, which in turn is operatively connected to the motor  14 A. A filter section  16 A is confluently connected to the pump  14 A in the same manner as in the embodiment of FIGS.  1 - 3 . While the filter  1   6 A operates to cleans the water entering the same from the separator  70  as well as the filter  16  did in the embodiment of FIGS.  1 - 3 , and the water being discharged from this system is now clean as opposed to the water being discharged thereby prior to being so modified, this separator did not function as well in removing contaminant from the exhaust gases. However in retrofit situations where because of structural problems, economic reasons, or no current exhaust gas regulation that the modified separator was unable to meet, the modified separator with the filtration of the water effluent is sufficient to meet water discharge regulations.  
         [0016]    While only two embodiments of this invention have been shown and described, it is understood that modifications can be made therein and separators other than those shown above modified without departing from the scope of this invention as claimed.