Water delivery and vacuum retrieval system

Abstract

A water delivery and vacuum retrieval system includes a rotatable boom for mounting on and rotation over a pressure cleaning apparatus. The boom has a rigid conduit extending from a free end to a freely-rotating housing. The boom also has a flexible conduit loosely fitted in the rigid conduit with the flexible conduit extending from the free end of the rigid conduit to a freely-rotating fluid coupling in the housing. The housing and fluid coupling are configured for independent rotation. In use, air space in the housing is placed in fluid communication with a vacuum portion of the pressure cleaning apparatus while the fluid coupling is placed in fluid communication with a water dispensing portion of the pressure cleaning apparatus.

Description

ORIGIN OF THE INVENTION

Pursuant to 35 U.S.C. §119, the benefit of priority from provisional application 61/068,774, with a filing date of Mar. 10, 2008, is claimed for this non-provisional application.

FIELD OF THE INVENTION

The invention relates generally to pressure washing systems, and more particularly to a water delivery and vacuum retrieval system used to supply a pressure washing system with water and retrieve wastewater generated by the pressure washing system.

BACKGROUND OF THE INVENTION

The cleaning of hard surfaces (e.g., concrete, asphalt, aggregate, etc.) is an issue for cities/municipalities, businesses, and the military. Cities/municipalities need to clean their streets, sidewalks and parking lots. Businesses need to clean their hard-floor warehouses and factories, as well as their sidewalks and parking lots. The military needs to maintain the cleanliness of its posts/bases, to include airstrips and tarmacs.

Over time, all of the above-noted surfaces get stained from a variety of natural and man-made substances. Most of the man-made substances are dried liquids that drip or are spilled onto one of the surfaces. For example, engine/transmission oil, gasoline and anti-freeze top the list of vehicle “droppings” that stain a hard surface. Spills of these and other products (e.g., paints, chemicals, food, drinks, etc.) add to the staining of a surface. The cleaning of dried-liquid stains from a hard surface has improved in recent years with the development of a variety of pressure cleaning and wastewater reclamation systems.

Wastewater reclamation has become increasingly important as federal, state and local regulations require the clean-up of wastewater from most pressure cleaning operations. Accordingly, most state-of-the-art pressure cleaning and wastewater reclamation systems have (i) one or more water hoses leading to a pressure washer wand or cleaning tool, and (ii) one or more vacuum lines leading to a vacuum tool that is separate from or integrated with the cleaning tool. As an operator walks or drives the cleaning and vacuum tool(s) over a surface, the water hose(s) and vacuum line(s) must be constantly manipulated and cleared from the area being cleaned. The task of hose/line manipulation and clearing is typically handled by an additional operator so the “cleaning” operator can concentrate on the surface being cleaned without worrying about the hose/line entanglements. Obviously, the use of an additional operator increases the overall cost for a surface cleaning operation.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a system for the delivery of high pressure water to a surface cleaning tool and for the vacuum retrieval of wastewater generated by the cleaning tool.

Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings.

In accordance with the present invention, a water delivery and vacuum retrieval system for use in pressure cleaning is provided. The system includes a rotatable boom adapted to be coupled to and above a pressure cleaning apparatus for rotation thereover. The boom has a rigid conduit extending from a free end to a freely-rotating housing. The boom also has a flexible conduit loosely fitted in the rigid conduit with the flexible conduit extending from the free end of the rigid conduit to a freely-rotating fluid coupling in the housing. An air space is defined between the housing and the fluid coupling. The housing and fluid coupling are configured for independent rotation. In use, the air space in the housing is placed in fluid communication with a vacuum portion of the pressure cleaning apparatus while the fluid coupling is placed in fluid communication with a water dispensing portion of the pressure cleaning apparatus. One or more tanks can be coupled to the boom via connecting lines/conduits that maintain a water-carrying line/conduit loosely fitted within a vacuum-carrying line/conduit.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention will become apparent upon reference to the following description of the preferred embodiments and to the drawings, wherein corresponding reference characters indicate corresponding parts throughout the several views of the drawings and wherein:

FIG. 1 is a schematic view of a water delivery and vacuum retrieval system in accordance with an embodiment of the present invention;

FIG. 2 is a side view of an embodiment of a boom system of the water delivery and vacuum retrieval system of the present invention;

FIG. 3 is a side view of an embodiment of a vacuum recovery tank system that can be used in the water delivery and vacuum retrieval system of the present invention;

FIG. 4 is a side view of another embodiment of a vacuum recovery tank system that can be used in the water delivery and vacuum retrieval system of the present invention; and

FIG. 5 is a schematic view of a belt-driven arm that can be coupled to the water delivery portion of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings and more particularly to FIG. 1, an embodiment of a water delivery and vacuum retrieval system in accordance with the present invention is illustrated within the dashed lines referenced by numeral 10. System 10 can be used in conjunction with a variety of pressure washing cleaning systems to deliver low or high-pressure (heated) water to cleaning tools and simultaneously retrieve (via vacuum) the wastewater generated by the pressure cleaning. Accordingly, by way of example, system 10 is shown coupled to a high-pressure hot water source 100, a vacuum source 102, and a pressure cleaning apparatus 200 (e.g., walk-behind, driven, etc.) that can include individual and separated sprayer tool(s) 202 and vacuum tool(s) 204. Tools 202 and 204 could also be incorporated into a combination tool without departing from the scope of the present invention. That is, system 10 can be used with either type of tool arrangement.

System 10 includes a boom system contained within the dashed lined referenced by numeral 20 and can include a vacuum recovery tank system contained within the dashed lines referenced by numeral 40. In general, boom system 20 manages both water supply and vacuum lines leading to tools 202/204 in a novel way that eliminates the need to manually monitor and manage these lines. Boom system 20 can be readily adapted to work with any walk-behind or driven pressure cleaning apparatus 200 on which tools 202/204 are mounted. In general, vacuum recovery tank system 40 links sources 100 and 102 in a novel way to boom system 20 (i) to supply water and vacuum thereto, and (ii) manage the wastewater passed therethrough.

Referring first to boom system 20, a support 22 rigidly couples boom system 20 to pressure cleaning apparatus 200 in order to support boom system 20 at a selected height above cleaning apparatus 200. As will be apparent from the following description, boom system 20 is maintained (by support 22) at a height that will be above the head of an operator 300 of cleaning apparatus 200.

In order to manage both water supply and vacuum lines, boom system 20 employs a rigid vacuum conduit 24 housing a flexible high-pressure water conduit 26. More specifically, vacuum conduit 24 is sized to loosely contain water conduit 26 so that air can flow along vacuum conduit 24 between the outer wall of water conduit 26 and the inner wall of vacuum conduit 24. At a free outboard end of this conduit arrangement, vacuum conduit 24 is open while water conduit 26 terminates in a readily-accessible and conventional coupling 26A (e.g., a “quick connect” coupling). At the other end of this conduit arrangement, vacuum conduit 24 terminates in a rigid and sealed fashion to a freely-rotating housing 28 while water conduit 26 terminates in a freely-rotating high-pressure fluid coupling 30 within housing 28. In general, housing 28 encases coupling 30 in an air space 28A so that air can flow freely around coupling 30. Each of housing 28 and coupling 30 is capable of 360° of independent rotation relative to support 22 and cleaning apparatus 200 as indicated by rotational arrows 29 and 31, respectfully.

The above-described conduit arrangement defines a substantially horizontal (i.e., with respect to the surface on which cleaning apparatus 200 rests) portion having a length “L” that is sufficient to position the free outboard end of the conduit arrangement (i.e., the end with water coupling 26A) beyond the normal operating position of operator 300. In this way, both water supply and vacuum lines coupled to and in the vicinity of cleaning apparatus 200 are maintained in a plane above operator 300/apparatus 200 regardless of the movement/positioning of operator 300/apparatus 200 since housing 28 and coupling 30 are capable of independent and free rotation.

A water line 32 couples rotating coupling 30 to sprayer tool(s) 202 while a separate vacuum line 34 couples air space 28A to vacuum tool(s) 204. As mentioned above, tools 202/204 can be separated from one another (e.g., a separate sprayer head with a vacuum trailing behind the sprayer head) or can be combined in a single spray/vacuum head without departing from the scope of the present invention. One embodiment of separated tools 202/204 could be an enclosed sprayer head that is trailed by a squeegee assembly having a vacuum coupled thereto to vacuum up wastewater corralled/collected by the squeegee assembly.

By way of example, an embodiment of the boom system of the present invention is shown in isolation in FIG. 2. Where appropriate, reference numerals used to describe elements of boom system 20 (FIG. 1) will be used in describing the embodiment in FIG. 2. Support 22 can be realized by a rigid pole 22A fixedly attached to a rigid plate 22B at a selected height above cleaning apparatus 200. A rigid T-pipe 60 is rigidly coupled and sealed to base plate 22B and is coupled to housing 28 by means of a sealing bearing 62 that allows housing 28 to freely rotate (as indicated by rotational arrow 29) relative to T-pipe 60 while allowing the interior of T-pipe 60 to be in fluid communication with air space 28A of housing 28. T-pipe 60 further defines an open conduit 60A to which vacuum line 34 is attached.

Water line 32 is led through air space 28A, bearing 62, T-pipe 60, and base plate 22B. Note that water line 32 is led through base plate 22B and sealing bearing 62 in a sealed fashion to prevent any loss of vacuum applied via vacuum line 34. Water line 32 is fixed in place by one or more of the structures it passes through so that water line 32 can serve as a fixed support for freely-rotating fluid coupling 30.

Vacuum conduit 24 is a rigid L-shaped pipe having a vertical portion 24A that is rigidly coupled to the top of housing 28 such that water conduit 26 can feed vertically into rotating coupling 30. A support brace 64 rigidly couples housing 28 to a point on the horizontal portion 24B of vacuum conduit 24 so that vacuum conduit 24 and housing 28 rotate in unison. Horizontal portion 24B extends for a length “L” as described above. Water conduit 26 loosely fits in vacuum conduit 24 as also described earlier herein. At the free end of water conduit 26 is a quick-connect coupling 26A. Note that coupling 26A can protrude from vacuum conduit 24 to facilitate attachment of a water line.

Referring again to FIG. 1, vacuum recovery tank system 40 serves as a link between sources 100/102 and boom system 20. Briefly, tank system 40 includes the following:

at least one tank 42,

a combination water/vacuum port defined by (i) rigid vacuum conduit 44 in fluid communication with the interior of tank 42 and having an open outboard end 44A, and (ii) a water line 46 passing into vacuum conduit 44 at 46A in a sealed fashion, and

a vacuum port 48 provided in a wall of tank 42.

Water line 46 terminates at either end thereof with couplings 46B and 46C (e.g., quick connect couplings) with coupling 46B being attachable to source 100 and coupling 46C being attachable to a flexible water line 76 used to connect water line 46 to water conduit 26. Vacuum conduit 44 is sized so that air flow is supported along vacuum conduit 44 between the outside of water line 46 and the inside of vacuum conduit 44. A flexible vacuum line 74 attaches to the outside of the outboard end of vacuum conduit 44 and to the outboard end of vacuum conduit 24. Such attachment can be by any conventional hose clamp, annular compression collar cuff, or a rotating collar or cuff without departing from the scope of the present invention. Water line 76 fits loosely within vacuum line 74 so that air flow is supported along vacuum line 74 between the outside of water line 76 and the inside of vacuum line 74.

In use, water source 100 is attached to coupling 46B and vacuum source 102 is coupled to vacuum port 48. Water is supplied to coupling 30 via lines/conduits 44, 74 and 24 contained within vacuum lines/conduits 46, 76 and 26, respectfully, that supply a vacuum to housing 28. As operator 300 pushes (or drives) cleaning apparatus 200 on a surface to be cleaned, boom system 20 keeps the water and vacuum lines/conduits up and out of the way of operator 300/apparatus 200. The free and independent rotation provided by housing 28 and coupling 30 maintain the proper orientation of water and vacuum lines regardless of the position of operator 300 and apparatus 200. This means that the cleaning operation will proceed faster and more efficiently without requiring an operator to monitor the various vacuum and water lines/conduits.

As mentioned above, the present invention can also include vacuum recovery tank system 40 that uses one or more tanks. Accordingly, by way of example, FIG. 3 illustrates a one tank system and FIG. 4 illustrates a two tank system. Where appropriate, reference numerals used to describe elements of tank system 40 (FIG. 1) will be used in describing the embodiments in FIGS. 3 and 4.

Referring first to FIG. 3, single tank 420 is a hollow tank that can have its sides reinforced as needed to withstand vacuum pressures that it will experience. Tank 420 is supported on legs 422 (or other type of base support) to allow a drain line 424 to be coupled to the bottom of tank 420. Drain line 424 is in fluid communication with the bottom region of tank 420 and terminates outside of tank 420 in a drain valve 426. A baffle or weir wall 428 is mounted in tank 420 to thereby define chambers 430 and 432 where vacuum conduit 44 communicates with chamber 430 and vacuum port 48 communicates with chamber 432.

As wastewater enters tank 420 via vacuum conduit 44, baffle/weir wall 428 traps most of the wastewater solids in chamber 430. The wastewater liquid can reside in chamber 430, but the wastewater liquid can also migrate through baffle/weir wall 428 and into chamber 432. Mounted atop tank 420 is a high-pressure water coupling 434 with a pipe 436 leading from water coupling 434 through chamber 430 to a point in tank 420 just above drain line 424. A float switch 438 disposed in chamber 432 can be provided/used to automatically activate a pump (not shown in FIG. 3) when the wastewater level in chamber 432 reaches a certain height. This pump is used to pump the wastewater from chamber 432 for treatment, disposal, etc.

Since tank 420 will be used to collect wastewater having solids mixed therein, tank 420 needs to be periodically purged. To do this, vacuum conduit 44 and port 48 are sealed and high-pressure water is applied to coupling 434 while drain valve 426 is opened. The high-pressure water is directed from coupling 434 to the bottom of tank 420 by pipe 436. The high-pressure water exiting pipe 436 pushes wastewater solids collected in the bottom of tank 420 into drain line 424. As a result, the wastewater's solids are driven from the bottom of tank 420 and out through drain line 424.

Referring now to FIG. 4, a two-tank system is illustrated that uses tanks 420A and 420B. Similar to tank 420, tanks 420A and 420B can be reinforced as needed to withstand vacuum pressures. Tanks 420A and 420B are serially connected to one another in terms of vacuum from vacuum source 102. Thus, tank 420B has a first vacuum port 48A coupled to vacuum port 48 of tank 420A by a line 450, and has a second vacuum port 48B coupled to vacuum source 102 by a line 452. Baffle or weir wall 428 is mounted in tank 420B to thereby define chambers 430 and 432 where vacuum port 48A communicates with chamber 430 and vacuum port 48B communicates with chamber 432. Note that no such baffle/weir wall is required in tank 420A. As described above, float switch 438 disposed in chamber 432 can be provided/used to automatically activate a pump 440 when the wastewater level in chamber 432 reaches a certain height. Pump 440 then pumps the wastewater in chamber 432 into a holding/treatment tank 442 where the wastewater can be treated for re-use or for environmentally-safe disposal.

As mentioned above, boom system 20 improves the speed and efficiency of a cleaning operation. Additional improvements can be achieved by coupling a direct drive system to the cleaning apparatus' spray head. More specifically and with reference to FIG. 5, most hard-surface pressure cleaning apparatus use a rotating arm spray head. A typical prior art spray head is referenced by numeral 80 and includes a water coupling 82, a rotating bearing 84, a spray arm 86 extending out from bearing 84 in opposing radial directions, and spray nozzles 88 mounted on the ends of spray arm 86 at an angle of inclination so that spray arm 86 rotates when high-pressure water exits nozzles 88. Under extreme high pressures of 3000-4000 PSI, spray arm 86 can achieve a rotation rate on the order of 1500 revolutions per minute (RPM). It has been found that this rotational speed can be doubled by coupling a motorized drive system 90 to, for example, rotating bearing 84. Drive system 90 can be realized by a motor and a belt (not shown) to bring about direct rotation of spray arm 86. By increasing the speed of the spray arm's rotation, it has been found that the cleaning apparatus can be pushed/driven at higher speeds thereby reducing the amount of time and cost to clean a hard surface. Further, the direct drive of the spray arm can be combined with the other features described herein to provide a novel hard-surface cleaning system that cleans better and more efficiently than currently-available systems.

Although the invention has been described relative to specific embodiments thereof, there are numerous variations and modifications that will be readily apparent to those skilled in the art in light of the above teachings. For example, other embodiments of the present invention could utilize the above-described boom system and vacuum tank recovery system independently of one another. That is, the boom system (or vacuum tank recovery system) could be coupled on a stand-alone basis to an existing pressure cleaning apparatus. In addition, the present invention is not limited to use with high-pressure water sources as it could also be used with low-pressure water sources without departing from the scope of the present invention.

While the various vacuum tank recovery systems described herein illustrate single vacuum ports for coupling to a vacuum tool, it is to be understood that additional vacuum ports could be provided to allow for simultaneous use of multiple vacuum tools. Further, the present invention could be used without the application of a vacuum for situations where the user wanted to collect/retrieve wastewater using a separate wastewater collection/handling system. Still further, if a separate tow-behind squeegee/vacuum were to be used to collect wastewater, a vacuum line could be directly coupled to the squeegee/vacuum in which case only a water line would be coupled to the boom system described herein. The boom system of the present invention could also be coupled to a pressure cleaning apparatus that had (i) an onboard reservoir/pump to supply high-pressure water for cleaning, and/or (ii) an onboard vacuum system and wastewater reclamation tank. In this instance, the above-described boom system could be used to manage the water supply line used to supply water to the onboard water reservoir and/or the vacuum line used to retrieve wastewater from the onboard wastewater reclamation tank for ultimate disposal or treatment. While the present invention has been described for use with pressure cleaning apparatus, it is to be understood that the boom system could also be coupled to a pushed or driven brush-type cleaning apparatus that uses liquid in a cleaning process. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described.

Claims

1. A water delivery and vacuum retrieval system for use in pressure cleaning, comprising a rotatable boom adapted to be coupled to and above a pressure cleaning apparatus for rotation thereover, said boom having a rigid conduit extending from a free end to a freely-rotating housing, said boom having a flexible conduit loosely fitted in said rigid conduit and extending from said free end of said rigid conduit to a freely-rotating fluid coupling in said housing wherein air space is defined between said housing and said fluid coupling, said housing and said fluid coupling capable of independent rotation, said air space in said housing adapted to be in fluid communication with a vacuum portion of the pressure cleaning apparatus and said fluid coupling adapted to be in fluid communication with a water dispensing portion of the pressure cleaning apparatus.

2. A system as in claim 1 wherein, when said boom is coupled to the pressure cleaning apparatus, said boom comprises a horizontal portion and a vertical portion, and wherein said housing and said fluid coupling are disposed in said vertical portion.

3. A system as in claim 2, wherein said housing is rigidly coupled to said horizontal portion.

4. A system as in claim 1, further comprising tank means coupled to said rotatable boom, said tank means defining at least one interior chamber coupled to said rigid conduit with said interior chamber adapted to be coupled to a vacuum source, said tank means further having a water distribution line for fluid coupling to said flexible conduit, said water distribution line adapted to be coupled to a pressurized water source.

5. A system as in claim 4, wherein a liquid/solid wastewater mixture collected from the vacuum portion of the pressure cleaning apparatus is deposited in said tank means, said system further comprising means for purging said tank means of solids from the wastewater mixture that collects in said tank means.

6. A system as in claim 4, wherein a liquid/solid wastewater mixture collected from the vacuum portion of the pressure cleaning apparatus is deposited in said tank means, said system further comprising means for automatically purging said tank means of liquid from the wastewater mixture that collects in said tank means.

7. A system as in claim 4, wherein a liquid/solid wastewater mixture collected from the vacuum portion of the pressure cleaning apparatus is deposited in said tank means, said system further comprising:

solids removal means for on-demand purging of said tank means of solids from the wastewater mixture that collects in said tank means; and

liquid removal means for automatically purging said tank means of liquid from the wastewater mixture that collects in said tank means.

8. A water delivery and vacuum retrieval system for use in pressure cleaning, comprising:

a rotatable boom adapted to be coupled to and above a pressure cleaning apparatus for rotation thereover, said boom having a rigid conduit extending from a free end to a freely-rotating housing, said boom having a flexible conduit loosely fitted in said rigid conduit wherein air can move through said rigid conduit and around said flexible conduit, said flexible conduit extending from said free end of said rigid conduit to a freely-rotating fluid coupling in said housing wherein air space is defined between said housing and said fluid coupling, said housing and said fluid coupling capable of independent rotation, said air space in said housing adapted to be in fluid communication with a vacuum portion of the pressure cleaning apparatus and said fluid coupling adapted to be in fluid communication with a water dispensing portion of the pressure cleaning apparatus; and

tank means coupled to said rotatable boom and defining at least one interior chamber coupled to said rigid conduit with said interior chamber adapted to be coupled to a vacuum source; and

a water distribution line for fluid coupling to said flexible conduit, said water distribution line adapted to be coupled to a pressurized water source.

9. A system as in claim 8, wherein said water distribution line passes through a portion of said tank means.

10. A system as in claim 8 wherein, when said boom is coupled to the pressure cleaning apparatus, said boom comprises a horizontal portion and a vertical portion, and wherein said housing and said fluid coupling are disposed in said vertical portion.

11. A system as in claim 10, wherein said housing is rigidly coupled to said horizontal portion.

12. A system as in claim 8, wherein a liquid/solid wastewater mixture collected from the vacuum portion of the pressure cleaning apparatus is deposited in said tank means, said system further comprising means for purging said tank means of solids from the wastewater mixture that collects in said tank means.

13. A system as in claim 8, wherein a liquid/solid wastewater mixture collected from the vacuum portion of the pressure cleaning apparatus is deposited in said tank means, said system further comprising means for automatically purging said tank means of liquid from the wastewater mixture that collects in said tank means.

14. A system as in claim 8, wherein a liquid/solid wastewater mixture collected from the vacuum portion of the pressure cleaning apparatus is deposited in said tank means, said system further comprising:

solids removal means for on-demand purging of said tank means of solids from the wastewater mixture that collects in said tank means; and

liquid removal means for automatically purging said tank means of liquid from the wastewater mixture that collects in said tank means.

15. A water delivery and vacuum retrieval system for use in pressure cleaning, comprising:

a rotatable boom adapted to be coupled to and above a pressure cleaning apparatus for rotation thereover, said boom having a rigid conduit extending from a free end to a freely-rotating housing, said boom having a flexible conduit loosely fitted in said rigid conduit wherein air can move through said rigid conduit and around said flexible conduit, said flexible conduit extending from said free end of said rigid conduit to a freely-rotating fluid coupling in said housing wherein air space is defined between said housing and said fluid coupling, said housing and said fluid coupling capable of independent rotation, said air space in said housing adapted to be in fluid communication with a vacuum portion of the pressure cleaning apparatus and said fluid coupling adapted to be in fluid communication with a water dispensing portion of the pressure cleaning apparatus;

tank means defining at least one interior chamber adapted to be coupled to a vacuum source;

a first flexible connecting conduit coupling said interior chamber of said tank means to said free end of said rigid conduit;

a water line passing into a portion of said tank means, said water line adapted to be coupled to a pressurized water source; and

a second flexible connecting conduit coupling said water line to said flexible conduit of said boom, wherein air can move through said first flexible connecting conduit and around said second flexible connecting conduit.

16. A system as in claim 15 wherein, when said boom is coupled to the pressure cleaning apparatus, said boom comprises a horizontal portion and a vertical portion, and wherein said housing and said fluid coupling are disposed in said vertical portion.

17. A system as in claim 16, wherein said housing is rigidly coupled to said horizontal portion.

18. A system as in claim 15, wherein a liquid/solid wastewater mixture collected from the vacuum portion of the pressure cleaning apparatus is deposited in said tank means, said system further comprising means for purging said tank means of solids from the wastewater mixture that collects in said tank means.

19. A system as in claim 15, wherein a liquid/solid wastewater mixture collected from the vacuum portion of the pressure cleaning apparatus is deposited in said tank means, said system further comprising means for automatically purging said tank means of liquid from the wastewater mixture that collects in said tank means.

20. A system as in claim 15, wherein a liquid/solid wastewater mixture collected from the vacuum portion of the pressure cleaning apparatus is deposited in said tank means, said system further comprising:

solids removal means for on-demand purging of said tank means of solids from the wastewater mixture that collects in said tank means; and

liquid removal means for automatically purging said tank means of liquid from the wastewater mixture that collects in said tank means.