Head Conversion Unit

Abstract

A tank for converting an overboard discharge type boat head to a recirculating sewage system includes a filter dividing the tank into receiving and recirculating chambers, a sump in the receiving chamber for facilitating tank discharge, a snap-on cover engaging the upper edges of the tank side walls, a rinsing nozzle for periodically cleaning the filter, and depressions formed in the tank side walls to accommodate tie-down bolts which extend from the cover to anchorages on the boat structure. The tank side walls are constructed from a translucent or transparent material so that the liquid level therein may be observed and a shoulder is formed in the side walls to indicate the correct level of priming materials in the tank.

Description

BACKGROUND OF THE INVENTION

Head facilities on many boats, particularly smaller craft, consist of a bowl, a flush water line extending from the bowl to a point exteriorly of the boat and below the water line, an electrically or manually operated pump for pumping fresh water through the flush water line into the bowl, and a discharge line leading overboard from the bowl for discharging the contents thereof.

Obviously systems of this type are undesirable since they permit raw, untreated sewage to be dumped into waterways. While at one time discharges of this type could be considered a negligible factor in water pollution, with the increase in population and the increased use of waterways for recreational boating, this has become a matter of increasing concern. This is evidenced by the fact that many jurisdictions now have ordinances prohibiting the discharge of untreated wastes into waterways and Federal legislation is proposed on the same subject.

While the pollution hazard which results from the use of overboard discharge marine heads is well recognized, the cost of converting such equipment to more elaborate sewage treatment systems is often prohibitive for the small boat owner. Thus such boat owners are presently faced with the dilemma of being unable to use their present overboard discharge type head but at the same time also unable to afford the cost of converting this type of equipment to an acceptable sewage treatment system.

SUMMARY OF THE INVENTION

The present invention provides a tank which may be incorporated with a minimum of plumbing work into a conventional overboard discharge type system to convert the system to a holding and recirculating treatment unit.

The tank is constructed with integrally formed side walls and bottom wall and a snap-on lid which engages the upper edges of the side walls to provide a sealing engagement therewith. A filter extends across the interior of the tank and divides it into a receiving chamber and a recirculating chamber. The top wall of the tank has all of the fitting attachments integrally formed therein including an opening into the recirculating chamber, a sewage receiving opening and a discharge opening into the receiving chamber, vent lines, and a spray nozzle fitting for rinsing the receiving chamber side of the filter.

The tank thus constructed may be incorporated in the existing overboard discharge system in a variety of ways. For example, the existing bowl discharge line may be connected to the sewage receiving opening of the tank and a line from the recirculation opening of the tank connected to the bowl flush line through the existing pump. With this arrangement sewage from the bowl passes through the discharge line to the receiving chamber of the tank where the major portion of the solids are retained and the liquid and finely divided solids allowed to flow through the filter to the recirculating chamber of the tank. Thus, liquid from this latter chamber may then be pumped to the bowl for flushing purposes.

Alternatively, instead of the line from the recirculation chamber of the tank being connected directly to the pump it may be joined by means of a three-way valve to the existing clean water line of the overboard discharge system, which was formerly used for flushing purposes. This arrangement permits clean water to be drawn from overboard through the existing clean water line and through the pump to the bowl and from the bowl through the discharge line to the tank for rinsing or priming purposes. Of course, in normal usage the three-way valve on the intake side of the pump will be repositioned so that the system operates, in effect, in the same manner as that described in the paragraph above.

A third possible arrangement would be to install a second three-way valve on the discharge side of the pump with a line extending from the second three-way valve to the spray nozzle. This configuration permits water to be drawn into the system from overboard through the existing clean water line, the first three-way valve on the intake side of the pump, the pump, the second three-way valve, and through a line to the spray nozzle. Of course, in those installations in which a second three-way valve is not provided on the discharge side of the pump the spray nozzle may be actuated by merely connecting any convenient source of spray water to the spray nozzle fitting.

With the converted sewage system the tank is first primed with water and color and odor control additives or bactericide. This may be accomplished by either adding the priming materials directly to the tank through an opening therein or by merely adding the control additives to the bowl and flushing the bowl with liquid from the clean water line. Preferably, the tank side walls are made of a transparent or translucent material so that the liquid level in the tank may be observed without opening the tank and a shoulder is provided in the side walls to indicate the correct prime level.

In use, discharge from the bowl is received in the receiving chamber of the tank and the liquid portion thereof is allowed to pass through the filter into the recirculating tank, with the major portion of the solids retained in the receiving tank and the liquid passing into the recirculating tank for subsequent use as flushing liquid; the existing manual or electrically operated pump for the head being utilized for this purpose.

Additionally, a separate pump may be mounted on the tank for discharging the contents of the receiving chamber to a dockside waste receptacle or to a bilge holding tank.

Thus, the present invention converts existing overboard discharge heads into an acceptable, nonpolluting sewage treatment system with a minimum of expenditure and alteration of the existing system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of the conversion tank of the present invention;

FIG. 2 is a top plan view of the tank with the top wall removed;

FIG. 3 is a perspective view of the lower surface of the top wall;

FIG. 4 is a cross sectional view taken on line 4--4 of FIG. 2;

FIG. 5 is a cross sectional view through a portion of the tank sides and top wall;

FIG. 6 is a cross sectional view taken on line 6--6 of FIG. 2;

FIG. 7 is an enlarged perspective view of the spray nozzle;

FIG. 8 is a cross sectional view through the top, side and bottom walls of the tank; and

FIG. 9 is a somewhat schematic representation showing one method of installing the tank of the present invention in an existing overboard discharge system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As seen in FIG. 1, the conversion tank 10 is constructed with integrally formed side and bottom walls 11, 12, 13, 14 and 15. As best seen in FIG. 5, the upper edges of the side walls are provided with a bead 16 projecting outwardly thereof while the top wall 20 is provided with a pair of continuous flanges 21 and 22 projecting downwardly therefrom about its periphery and defining a cavity 23 for receiving the upper ends of the side walls in sealing engagement therewith. At spaced intervals along the outer flanges 22 a series of ledges 24 are positioned, projecting inwardly into the cavity 23 to form a snap-on fitting with the outwardly projecting bead 16.

As best seen in FIGS. 1, 2, 4 and 8, a filter plate 30 is positioned in the tank 10 dividing it into a receiving chamber 31 and a recirculation chamber 32, the chambers 31 and 32 communicating with each other by means of openings 33 formed in the filter plate 30 and tapering outwardly, as best seen in FIG. 4, from the receiving chamber 31 towards the recirculation chamber 32. Integrally formed with the bottom wall 15, side walls 12 and 14, and top wall 20 are inwardly projecting pairs of ribs 34, 35, 36 and 37, respectively, which engage peripheral portions of the filter plate 30 and retain it in position in the tank 10.

With reference to FIGS. 1 and 3, it will be seen that the top wall 20 is provided with a series of openings therethrough terminating in inwardly projecting bosses on the underside of the top wall with the bosses interconnected by ribs to provide reinforcement for the structure. Thus, an opening 40 having the inwardly projecting boss 41 provides access to the interior of the recirculation chamber 32 while on the opposite side of the filter plate 30 openings 42, 43, 44 and 45 are formed in the top wall 20 and have inwardly projecting bosses 46, 47, 48 and 49, respectively.

An additional opening 50 is also formed through the top wall 20 on the receiving side of the tank leading to a spray nozzle 51, which, as best seen in FIGS. 3 and 7, is provided with a central nozzle opening 52 and additional openings 53 disposed on either side of the opening 52. The position and angular disposition of the openings 52 and 53 are selected such that a jet of rinsing liquid pumped to the nozzle 51 will be ejected therefrom in fan-shaped sprays designed to cover substantially the entire receiving chamber side of the filter plate 30.

The openings 40, 43, 44, 45 and 50 are threaded to receive the externally threaded ends of the elbows 60, 61, 62, 63 and 64, respectively. Opening 42, on the other hand, is provided with an inclined, inwardly projecting rim 65 having a series of notches 66 formed therein to receive lugs, not shown, projecting outwardly from the lower surface of the cap member 67 to provide a conventional bayonet type connection.

The external surfaces of bosses 41 and 48 are tapered inwardly towards the bottom wall 15 of the tank 10 and match complementarily tapered interior surfaces of the conduits 70 and 71, respectively. Conduit 70 thus extends inwardly from the boss 41 and is selected to be of a length such that its lower end is spaced a short distance above the bottom wall 15 on the tank 10. As best seen in FIGS. 2 and 6, one corner of the receiving chamber portion of the tank 10 is depressed downwardly to define a sump 72 and conduit 71 is formed of a length such that it extends from the boss 48 downwardly into the tank 10 with its lower end positioned a short distance above the bottom wall 73 of the sump 72. It will also be noted from FIGS. 1, 2, 4 and 8 that a peripheral rib 75 and a plurality of longitudinally extending ribs 76 project downwardly from the bottom surface of the tank 10 with the lower surfaces of the ribs 75 and 76 and the exterior surface 77 of the sump being coplanar to impart stability, as well as reinforcement, to the tank structure.

It will also be noted from FIGS. 1 and 2, that the side walls of the tank 10 are each provided with inwardly depressed portions forming vertically extending bolt receiving slots 80 and that openings 81 are formed in the cover 20 in the portions of the top wall which extend outwardly over the slots. J-bolts 82 having threaded upper ends 83 are received in each of the openings 81 and are secured therein by means of the nuts 84 threaded onto the J-bolts with a washer 85 interposed between the upper surface of the top wall 20 and the nut 84. Eyebolts or the like, not shown, are mounted on the boat structure at positions corresponding to the slots 80 to form anchorages for seating the hooked lower ends 86 of the J-bolts 82 to securely fasten the tank 10 to the boat structure as well as provide an additional securement of the top wall 20 to the upper edges of the side walls of the tank.

In a conventional overboard discharge type head a line will usually be provided extending from outside the boat below the water line thereof to the bowl to provide flushing water for the bowl and a discharge line will extend from the bowl to a point outside the boat for discharging the contents of the bowl each time it is flushed by means of either a manually or electrically operated pump. The conversion tank of the present invention may be installed in a system of this type in a number of ways.

Thus, as seen in FIG. 9, a line 90 may be provided extending from the elbow 60, which is in communication with the recirculation chamber 32, and connected to the existing clean water line 91 by means of a three-way valve 92. The existing clean water line is in turn connected to the intake side of the pump 93 of the overboard discharge system with the discharge side of the pump 93 in communication with the bowl 94 by means of a flushing line 95. A discharge line 96 then extends from the bowl to the receiving chamber 31 of the tank 10 and a second three-way valve 97 may be positioned in line 95 and connected to the spray nozzle 51 by means of a line 98.

With this arrangement relatively clean water may be drawn into the system through the line 91, the inlet end of which will be positioned beneath the water line of the vessel, and the clean water routed through the first three-way valve 92, the pump 93, line 95, bowl 94 and discharge line 96 to place a priming charge of liquid in the tank 10. After this initial priming operation, which will also preferably include the addition of color and odor control additives or a bactericide, valve 92 will be repositioned to effectively remove line 91 from the system and place line 90 in communication with the pump 93.

Thereafter when the system is used, sewage will pass from the bowl 94 through the line 96 to the receiving chamber 31 of the tank 10. The filter plate 30 will permit the liquid portion of the sewage as well as finely divided solids to pass from the receiving chamber to the recirculation chamber 32 while the majority of the solids are retained in chamber 31. Liquid which collects in the recirculation chamber 32 may then be withdrawn therefrom through the line 90 each time the system is used to flush the bowl 94.

It will be noted that the tapered configuration of the openings 43 in the filter plate decreases the incidence of clogging since any material which enters the openings 33 from their smaller end on the receiving chamber side of the filter must readily pass through the openings into the recirculation chamber. To further insure that the filter plate remains unclogged during use, cleansing liquid may be sprayed through the openings 52 and 53 of the nozzle 51 against the receiving chamber side of the filter plate by repositioning valves 92 and 97 so that clean water drawn into the system through the existing clean water line 91 will pass through the line 91, the first three-way valve 92, pump 93, line 95, second three-way valve 97, line 98 and spray 51.

As noted previously there are other plumbing configurations which can be used to convert an existing overboard discharge system by means of the present invention. For example, valve 97 may be dispensed with and spray nozzle 51 actuated by connecting the spray nozzle to any convenient source of cleansing liquid under pressure.

Additionally, the first three-way valve 92 may also be dispensed with and the line 90 connected directly to the intake side of the pump 93. With this arrangement the tank is initially primed by adding a priming charge of water and additives for color and odor control or a bactericide to a tank by either placing them in the bowl where they may be conveyed through the line 96 to tank 10, or by placing the priming materials directly into the tank by removing the cap 67 over the opening 66. In this regard it will be noted that the tank side walls are preferably constructed of a translucent material and a shoulder is formed in the side walls as shown at 99 in FIGS. 1 and 8, to indicate the correct depth of priming material in the tank 10.

After repeated uses of the head the contents of the receiving chamber 36 may be emptied into suitable dockside facilities or into a larger, bilge holding tank located on the boat. In this regard, it will be seen that by providing the sump 72 in the receiving chamber and extending the conduit 71 downwardly from the discharge opening 44 to a point spaced just above the bottom floor 73 of the sump, substantially the entire contents of the tank may be evacuated through the conduit 71 discharge opening 44, elbow 62 and associated tubing.

From the above it will be seen that the present invention provides an inexpensive means of converting an existing overboard discharge head to a more acceptable, nonpolluting, holding and recirculating type system which for the most part incorporates existing components of the overboard discharge head.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

Claims

What is claimed is:

1. Apparatus of the type described comprising:

a. a tank including upwardly extending side walls and a bottom wall extending between and interconnecting said side walls,

b. a portion of said bottom wall being downwardly depressed and defining a sump therein,

c. means projecting downwardly from the exterior surface of said bottom wall and having lower surfaces coplanar with the lower surface of said downwardly depressed portion,

d. portions of said side walls being inwardly depressed and defining vertically extending bolt receiving slots,

e. said side walls terminating at their upper ends in a continuous outwardly projecting bead,

f. a top wall having a pair of continuous flanges extending downwardly therefrom about the periphery thereof and defining a cavity receiving said upper ends of said side walls,

g. a series of spaced ledges mounted on the outer one of said flanges and projecting inwardly of said cavity in engagement with said bead,

h. portions of said top wall positioned outwardly of said outer one of said flanges in alignment with said bolt receiving slots having means defining openings therein,

i. pairs of spaced apart inwardly projecting ribs mounted on said bottom wall, said top wall and an opposing pair of said side walls and defining a series of coplanar slots,

j. a filter plate received in said slots and extending between said bottom wall and top wall and said opposing pair of side walls and dividing said tank into a receiving chamber and a recirculation chamber,

k. means defining a plurality of openings through said filter plate with said openings tapering outwardly toward said recirculation chamber,

l. means defining an opening through said top wall into said recirculation chamber,

m. means defining a pair of openings through said top wall into said receiving chamber with one of said openings positioned above said sump, and

n. means mounted in said top wall for directing jets of rinsing liquid against said filter plate on the receiving chamber side thereof.

2. In a boat having an overboard discharge type of head, including a clean water line in communication with a source of relatively clean water, a pump for directing flushing water to the head, and a discharge line from the head for removing the contents thereof, the improvement comprising:

a conversion unit for converting an overboard discharge type boat head to a recirculating sewage system, including;

means defining a substantially closed tank;

filter means dividing said tank into a receiving chamber having at least one inlet and a recirculation chamber having at least one outlet;

means defining a sump in said tank for facilitating the evacuation of sewage from said tank;

means for connecting the discharge line from said head to the inlet of said receiving chamber;

means for connecting the intake side of said pump to the outlet of said recirculation chamber to provide filtered, recirculated flushing water to said head upon energization of said pump; and

means for connecting the clean water line to the intake side of said pump to provide additional flushing water to said head.

3. A boat head conversion unit as recited in claim 2, which further comprises:

valve means positioned in said connecting means for said intake side for alternately placing said intake side of said pump in communication with said recirculation chamber or said clean water line.

4. A conversion unit as recited in claim 2 which further comprises:

a spray nozzle mounted in a wall of said tank and projecting inwardly into said receiving chamber; and

means for connecting the outlet of said pump with said spray nozzle to supply water to the spray nozzle so that the filter can be rinsed.

5. In a boat having an overboard discharge type of head, including a pump for directing flushing water to the head, a discharge line from the head for removing the contents thereof, the improvement comprising:

a conversion unit for converting an overboard discharge type boat head to a recirculating sewage system, including;

means defining a substantially closed tank;

an upstanding wall having openings therein for filtering said sewage and for dividing said tank into a receiving chamber and a recirculation chamber, said receiving chamber having at least one inlet, and said recirculation chamber having at least one outlet;

means for directing a fluent spray against said wall to rinse solid sewage therefrom;

means for connecting the discharge line from said head to the inlet side of said receiving chamber; and

means for connecting the intake side of said pump to the outlet of said recirculation chamber to provide filtered, recirculated flushing water to said head upon energization of said pump.

6. A boat head conversion unit as recited in claim 5, which further comprises:

a clean water line extending from a source of relatively clean water and connected to said intake side of said pump; and

valve means positioned in said connecting means for said intake side for alternately placing said intake side of said pump in communication with said recirculation chamber or said clean water line.