US 3853138 A
An arrangement and method for conveying liquid by vacuum, such as sewage, through long conduits without intermediate stations having vacuum generating means. The arrangement results in an efficient liquid transport in conduits of considerable length and also in installations where there is a considerable difference in height of parts of the liquid flow path.
Description (OCR text may contain errors)
United States Patent 1191 Amren 1 Dec. 10, 1974 METHOD AND APPARATUS FOR 3,620,408 11/1971 Holbrook et al .1 137/205 ux CONVEYING LIQUID THROUGH A LONG 3,686,693 8/1972 Liljendahl 137/205 X 3,730,884 5/1973 Burnset al 137/205 ux CONDUIT  Inventor: Jan Vilhelm Amren, Sollentuan,
Sweden  Assignee: Aktiebolaget Electrolux, Stockholm,
Sweden  Filed: Apr. 25, 1973  Appl. No.: 354,337
 Foreign Application Priority Data Apr. 26, 1972 Sweden 5530/72  US. Cl 137/1, 4/1, 137/205  Int. Cl. C02c 1/00-  Field of Search 137/173, 174, 205, l; /1, 77
 References Cited UNITED STATES PATENTS 334,083 1/1886 Moran 137/423 X V/JZV55 3 FOREIGN PATENTS OR APPLICATIONS 415,747 7/1925 Germany 137/205 504,528 11/1952 Belgium ..137/629 Primary Examiner-William R. Cline Assistant Examiner--Gerald A. Michalsky [5 7 ABSTRACT An arrangement and method for conveying liquid by vacuum, such as sewage, through long conduits without intermediate stations having vacuum generating means. The arrangement results in an efficient liquid transport in conduits of considerable length and also in installations where there is a considerable difference in height of parts of the liquid flow path.
7 Claims, 2 Drawing Figures 40-70574515 T/M/A/G 05/065 35 33 ADJUST/Na MEANS 395/ '1 METHODAND APPARATUS FOR CONVEYING LIQUID THROUGH .A LONG CONDUIT BACKGROUND OF THE INVENTION It is known that when liquid, for example, sewage, is conveyed through a long conduit which may have upwardly sloping sections, it is desirable that the liquid movement is brought about by a vacuum. Thus, the conduit does not have to be provided with continual general downgrade, but can. more or less follow the contour of the ground. However, if there are large variations in the level of the ground, difficulties may arise since the vacuum available must be sufficient to raise the liquid to a level corresponding to the total difference in height between certain portions of the conduit. Nevertheless, the avialable vacuum in an arrangement for conveying liquid can be used to lift liquid considerably higher if the liquid is mixed with air. Thus, a liquid column in a riser will have a lower specific weight and may be considered as equivalent to a considerably shorter liquid column.
The mixing of air with the liquid to be transferred from one place to another has the advantage of causing the improved acceleration of the liquid when its transport is commenced. Moreover, the large forces which are present when a liquid column in a long conduit is the receptacle may be again mixed withair during the continual passage through the vacuumpipe.
An object of the present invention is to selectively introduce atmospheric air into the apparatus in order to create a pressure difference in the system to. thereby effect a continual transport of the collected liquid through the long conduit.
Another object of the present invention is to provide more than one level sensing means inthe collecting receptacle to operate a vacuum controlled valve connected through a vacuum conduit to a control device.
. method for effectively conveying liquid by vacuum stopped are considerably reduced by mixing the air with the liquid. s
In spiteof the intermixing of air with the liquid to be transported, this alone was not sufficient to effectively convey the liquid, because of large differences in height of sections of the vacuum conduit. Prior to the present invention, it was not possible to use transport conduits of considerable length without costly interme diate way stations along the long conduit which are equipped with vacuum generating means.
The present invention relates to an apparatus and method for effectively conveying liquid by vacuum through long conduits. An object of the present invention is to provide an arrangement for conveying liquid by vacuum through long conduits and without employing expensive intermediate stations for increasing the vacuum supply to the system. Instead of utilizing the aforesaid expensive intermediate stations, a simple and inexpensive means is provided at a selected location or locations along the vacuum conduit which makes it possible for an effective conveyance of the liquid even when there is a great difference in height of various sections of the long conduit.
It is another object of the present invention to provide a construction having a liquid collecting receptacle provided with an inlet to which the input of the vacuum pipe is connected. The receptacle has a first outlet to which the output of the vacuum pipe is connected and a second outlet opening to which is connected an air conducting conduit having a valve that is open in the idle position. The air conducting conduit is connected to the output of the vacuum pipe.
A further object of .the present invention is to provide a method and apparatus for conveying liquid by vacuum in which only a small portion of the liquid conveyed is present in the vacuum pipe while air is in the pipe at all times and assists in the efficient transport of liquid through the long conduit. The liquid collected in through long conduits in accordance with the teachings of my invention; and
FIG: 2 is a diagrammatic view of an alternate embodiment of the invention disclosed in FIG. 1.
DES RIP ON. OF H R FERRE EMBODIMENTS As seen in FIGS. 1 and 2, a collecting receptacle 10 is shown which is provided with an inlet pipe9 having an inlet opening 11 as well as an outlet opening 12 in the bottom of the receptacle. Another outlet opening 13 is located-in the side of the receptacle 10 rather close to the top thereof. The input portion of the vacuum conduit the reference numeral 15 and is nne t d t the inlet Pip 9 y me of a che va e Th o tlet P r n of t eeh m con t b r e reference numeral 16 and is connected to the outlet opening 2 in e bottom o t r c pt c e- A s t conduit 18 is connected between the outlet opening l3 d e ut et PI1i0l1 16 of the a um ond i a he location 17. A vacuum controlled valve 19 which is open when in the idle position is coupled to the shunt conduit 18.
Referring particularly to FIG. 1, the receptacle 10 is shown having two level sensing means 20 and 21. Both of he lev l sing means a P ovide with Connectien e em C whi h an be ma oper t e e n r at e by t e act on of a p e u ens g de e s as a diaphragm .8.- Th l el s ns n mea s n .2 are dependent upon the level of the liquid 22 in the receptacle 10 and each is arranged to open and close en ex s l n (3 t een h ve uhm .e ndu t 23, 4 M 2536, esp c v y-. 1 ent es-end ng manner, the level sensing means 217, illustrated in FIG. 2, is c p d t theoutletp rt ntfi h va u m eendu t to open or close the connection elements C between the vacuum conduits 28 and As seen in FIG. 1, acontrol device 30 is shown which is connec ed t the eve sens mean 20 -.en 1
' through th v c m ondu ts .2 25 a 26 resp It should be noted that thevacuum conduit 16 has continuous sub-atmospheric pressure prevailing therein, that forms a vacuum which is transferred to the control device 30 by the conduit 32. A nipple 33 isconnected to the control device for the admission of atmospheric air thereto. This atmospheric aircan be further conducted by the control device 30 to'the. receptacle by means of the airconduit 34,, andto the outlet portion 16 of the vacuum conduitby. means of another air conduit 35. I I
The control device 30 is provided with valves 37 that interconnect the conduits and the control valves 19. The valves 37 can be controlled by the vacuum prevailing in the conduit 16 and by an adjustable timing device 38 which is also positioned within control device 30. Furthermore, the control device is provided with an adjustable means 39 for selectively varying the quantity of air mixed with the liquid.
The apparatus disclosed herein operates as follows: a mixture of air and liquid flows through the input portion of the vacuum conduit and the check valve 14 to the receptacle 10. The latter is located in the system immediately ahead of the riser section of the outlet portion 16 of the vacuum conduit. The liquid is separated and collected in the receptacle 10 while the air passes through the outlet 13 and the shunt conduit 18. The latter serves as an air conduit to an upper part of the outlet portion 16 of the vacuum conduit. The valve 19 is open because vacuum is supplied to it from the vacuum conduit 16 through the conduit 32, the control device 30, and the conduit 31. The level of the liquid 22 collected in the receptacle 10 is sensed by the level sensing means and 21, and when the liquid level has reached the level sensing means 20 or is slightly above it, the control device 30 is acted upon through the-conduits 23 and 24 to close the valve 19. This result can be achieved, for example, in such a manner that air of at.-
' mospheric pressure passes through the nipple 33 to an operating member of the valve 19. Simultaneously, the control device 30 transfers air of atmospheric pressure to the upper part of the receptacle 10 through the conduit 34. Since the outlet portion 16 is under vacuum, the pressure difference prevailing on either side of the liquid 22 in the receptacle 10 will generate a considerable force to raise the liquid upward in the upward sloping outlet portion 16 of the vacuum conduit.
Thus, in order to ensure the transport of the liquid when there is a large height difference and to improve the subsequent transport through the vacuum conduit,
the liquid being conveyed is again mixed with air. This is brought about by the control device 30 which supplies air to the location 36in the outlet portion 16 of the vacuum conduit. The control means 30 is provided with adjusting means 39 that facilitates the variation of the quantity of air to be mixed with the liquid. In this regard, it should be noted that if the differences in height are great, more air is mixed with the liquid than if there are small differences in height. If several arrangements constructed in accordance with the teachings of the present invention are located at spaced locations along a long vacuum conduit, it will thus be possible to adjust each arrangement individually to provide the most favorable transport of liquid in the conduit. The intermixing of a large quantity of air in the liquid mesns that the quantityof liquid which on one occasion is to be lifted to a higher level canbe proportioned so as to be small enough to be well below the length of the largest solid liquid column that the available vacuum is capableof conveying.
When the level of the liquid 22 in the collecting receptacle 10 has decreased, the level sensing means 20 is no longer acted upon. However, the valve 19 is maintained in a closed condition because the level sensing means 21 is still being acted upon by the liquid 22. However, when the level of the liquid 22 in the receptacle 10 drops below the level sensing means 21, the timing device 38 is switched on which maintains the valve 19 in a closed condition during an easily adjustable period so that the receptacle l0 and the upwardly rising outlet portion of the vacuum conduit is emptied of liquid. Accordingly, the instant construction and arrangement ensures that the impurities present in the receptacle .10 are removed. If it is not necessary to completely empty the receptaclelt), the control device 30 can be set, of course, to open the valve 19 immediately after theliquid level 22 rises and has passed the level sensing means 21.
Thecheck valve 14 functions to prevent air of atmospheric pressure from passing into the inlet portion 15 of the vacuum conduit. However, when valve 19 again opens, the liquid is continued as before through the check valve 14 to the receptacle 10. The intermixed air passes through the shunt conduit 18 to the outlet portion 16 of the vacuum conduit. A small quantity of liquid may follow the transported air through the shunt conduit 18, but this liquid will settle on the walls in the upwardly rising outlet portion 16 and will consequently flow back to the receptacle 10.
Referring to FIG. 2, it will be noted that the construction shown therein functions in the same manner as the arrangement shown in FIG. 1 with the exception that only one level sensing means 27 is used. The level sensing means 27 can be set to act on the control device 30 when a predetermined level of liquid 22 hasbeen reached in the receptacle 10. Moreover, the timing device 38 can be arranged to keep the valve 19 closed for a period of time that is necessary to empty the receptacle 10. The level sensing means 27 may be adjusted so as to act again on the control device 30 when the level of the liquid has been depressed below the means 27. As seen in FIG. 2, the location of the means 27 ensures that the receptacle 10 can be completely emptied.
The control device 30 having valves 37 and an adjustable timing device 38 as well as the valve 19 and the level sensing means 20, 21, and 27 are operated by a vacuum. The vacuum source of supply is the vacuum present in the portion 16 of the vacuum conduit. In this arrangement, there is no dependence on a supply source outside of the present conveying system. Accordingly, the arrangement is self-sustaining. Furthermore, the present arrangement can be connected anywhere along a long vacuum conduit and also at locations which are difficult to reach. In addition, the present arrangement can be modified to operate electrically.
The apparatus and method herein described results in an effective but economical conveyance of liquid, such as sewage, through long conduits which may have height differences.
What I claim:
r 1. In an apparatus for conducting liquid from a collectingreceptacle to a long conduit and including a source of vacuum comprising: a liquid collecting receptacle, meansforsupplying a mixture of air and liquidto said receptacle, said conduit having an inlet portion connected to the bottom of said collecting receptacle and extending below the plane of said bottom, said conduit having an outlet portion provided with an upwardly sloping section through which the liquid flows by means of said vacuum, an air-conducting shunt pipe located above the inlet portion and connecting the upper part of said receptacle to said upwardly sloping section, the opposite ends of said shunt pipe being positioned at substantially the same level, said shunt pipe being provided with a valve, control means for said valve, said valve being open in the idle position of said apparatus thereby permitting the air to flow through the shunt pipe and collecting the liquid in the receptacle, and at least one liquid level sensing means in said receptacle to operate said control means for opening and closing said valve, said liquid in the collecting receptacle being mixed with air and conveyed through the conduit when the valve is in the closed position.
2. The apparatus as claimed in claim 1 wherein two liquid level sensing means are provided in the receptacle, one of said means being located in the bottom of the receptacle and the other means being positioned adjacent to the top thereof.
3. The apparatus as claimed in claim 1 further comprising means connecting the control means to the normally open valve and to the liquid level sensing means, said control means being provided with additional valve means to admit air to the receptacle and to the outlet portion of the long conduit when the normally open valve is closed under the action of the liquid level sensing means when a given liquid level has been reached in the receptacle.
4. The apparatus as claimed in claim 3 wherein said control means is provided with an adjustable timing device means for determining the time period during which the normally open valve is closed and the continued transport of the collected liquid in the long conduit.
5. A method for conducting liquid from a collecting receptacle and through a long conduit connected thereto having an upwardly sloping section, supplying a mixture of liquid and air to said collecting receptacle, separating the air from the liquid in the receptacle, passing the separated air through a shunt pipe connecting the upper portion ofthe receptacle to the upwardly sloping section of the long conduit, collecting the liquid in the receptacle, conveying the liquid through the conduit by closing a valve in the shunt pipe when the liquid has reached a predetemiined level in the receptacle, and mixing air into the liquid while said liquid is being conveyed.
6. The method as claimed in claim 5 further supplying atmospheric air to the liquid to create a pressure difference in the system that effects a continued transport of the collected liquid through said conduit.
7. The method as claimed in claim 5 wherein said collecting receptacle where the air is separated from the liquid is immediately ahead of an upwardly sloping part of the conduit.