US 3651524 A
A sanitary drain system for a building in which a plurality of waste water drains are connected to a soil pipe and with the outlet end of the soil pipe being provided by a hydraulic closure. A vacuum is provided in the soil pipe and an inlet valve is provided in the connection between each waste pipe and the soil pipe. The inlet valve is of the type which is responsive to the vacuum in the soil pipe to remain closed in the absence of waste water in the drain at the inlet side of the valve. However, the inlet valve opens when there is water in the drain at the valve's inlet side so that waste water and also solid wastes can readily pass through the valve and thence through the soil pipe to the sewer.
Description (OCR text may contain errors)
United States Patent Bengtsson et a1.
 3,651,524 [4 1 Mar. 28, 1972 [541 VACUUM DRAIN SYSTEM  Inventors: Lars-Erik Bengtsson; Claes G. Allander,
both of Stockholm, Sweden  Appl. No.: 11,764
 Foreign Application Prlority Data Feb. 14, 1969 Sweden ..21ll/69 521 U.S. Cl ..4/211 51 Int. Cl ..E03d 9/04  Field of Search ..4/9, 10, 14,15, 77, 89, 90, 4/92,76,111,115,116,120,128,191, 211, 219; 210/152, 173
 References Cited UNITED STATES PATENTS 3,047,013 7/1962 Baumbach ..137/525.1
482,439 9/1892 Liernur ..137/236 2,662,724 12/1953 Kravagna ..25 l/122 2,793,371 5/1957 Le Vesconte... ..4/76
3,034,131 5/1962 Lent ..2/2.l 3,115,148 12/1963 Liljendahl ..l37/20S 3,477,949 11/1969 Liljendahl ..2l0/48 FOREIGN PATENTS OR APPLICATIONS Denmark Italy Great Britain ..4/ 1 15 Primary Examiner-Samuel B. Rothberg Assistant Examiner-Donald B. Massenberg AttorneySommers & Young ['51] ABSTRACT A sanitary drain system for a building in which a plurality of waste water drains are connected to a soil pipe and with the outlet end of the soil pipe being provided by a hydraulic clo sure. A vacuum is provided in the soil pipe and an inlet valve is provided in the connection between each waste pipe and the soil pipe. The inlet valve is of the type which is responsive to the vacuum in the soil pipe to remain closed in the absence of waste water in the drain at the inlet side of the valve. However, the inlet valve opens when there is water in the drain at the valves inlet side so that waste water and also solid wastes can readily pass through the valve and thence through the soil pipe to the sewer.
5 Claims, 5 Drawing Figures WIIIIIIIIIJUIIII W/IIIIIIIIIIIII.
Patented March 28, 1972 2 Sheets-Shea: l
Mi li/[(111711]! LARS-ERIK BENGTSSGN CLAES G.ALLANDER by Saywwwd M Patented March 28, 1972 2 Sheets-Sheet 2 IIIILIII.
LAWS-ERIK sENw-ssa/v CLAES G. ALLANDER VACUUM DRAIN SYSTEM BACKGROUND OF THE INVENTION This invention relates to a drain system for houses, especially big buildings, wherein the drain water supplied to housepipes through inlet openings provided with inlet valves is transported in the house-pipes under the influence of vacuum.
A drain system using vacuum is known, which system is provided with a hermetically closed vacuum tank into which the drain water is supplied by opening of an inlet valve permitting inflow of drain water in the form of a water piston into the house-pipes. The system permits the transport of water having a large content of solid particles in pipes having a very small area, and in horizontal pipes as well as pipes connected to a vacuum tank located at a higher level than the inlet valve. A serious inconvenience is, however, that a strong vacuum is necessary in the house-pipes and that the entire system forms a hermetically closed system when the inlet valves are closed. Transportation of the water occurs only when the inlet valves are open, and, when inlet valves close, resonance phenomena occur causing pressure variations swinging between strong vacuum and overpressure in the system, which latter is a serious inconvenience making it necessary to combine the inlet valves with complicated nonreturn valves.
A drain system is also known utilizing a vacuum streetsewer pipe system connected to a conventional house-pipe .system via a hydraulic closure or trap. The house-pipe system,
SUMMARY OF THE DISCLOSURE The object of the invention is to overcome all these objectionable features of the known systems. This is accomplished by providing a drain system comprising house-pipes, which can be horizontal or slope upwardly, inlet openings provided with inlet valves and connected to said house-pipes, a common outlet pipe for said house-pipes, a hydraulic closure at the outlet end of said outlet pipe, means connected to the inlet end of said outlet pipe for maintaining vacuum in said housepipes and means connected at least to the most distant parts of the house-pipes, as seen from the outlet pipe, for throttled outside air inlet into the house-pipes. The throttled outside air inlets are preferably arranged to inject air at the vacuum sides of the inlet valves, so that a closed inlet valve cannot prevent the flow of drain water from an inlet valve to a house-pipe. The drain water flowing in the house-pipes is accelerated under the influence of additional outside air inlets which become effective and the drain water is split into drops which, together with solid particles, are carried by the air stream with a high velocity to the hydraulic closure in which drain water and solid particles, but not air, pass downwardly.
The system according to the invention requires a moderate vacuum making it possible to use very simple inlet valves having flexible walls presenting inner surfaces bearing against each other and, under the influence of the vacuum in the house-pipes, being airtight and pressed against each other. Such a valve is impervious to air but not to water and can be used even in connection with a conventional water-closet having the usual hydraulic closure outlet.
BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and accomplishments will become obvious from the following description in which reference is made to the accompanying drawings in which FIG. 1 schematically illustrates an embodiment of the system according to the invention in a sectional view,
FIG. 2 is a front view of an automatic inlet valve,
FIG. 3 is a sectional view on line III-Ill of FIG. 2,
FIG. 4 is a side view of the inlet valve shown in FIG. 2, and
FIG. 5 is a sectional view of a preferred embodiment of the inlet valve.
DETAILED DESCRIPTION OF THE INVENTION The drain system shown in FIG. 1 has a vertical said pipe 1 and a plurality of substantially horizontal branch waste pipes 2, 3, 4 to which a lavatory 5, a draining gutter 6 and a watercloset 7 are connected via inlet valves 8, 9 and 10, respectively. All these pipes have a diameter which is about half the diameter of conventional drain pipes, and the branch waste pipes 2, 3, 4 are located in a thin .framing of joists in which the pipes, if necessary, can extend upwards around a joist in the framing of-joists. The pipe 1 is connected to a pipe 1 l to which a suction pipe 12 is branched via a water separator tank 13 and a branch pipe 14. The pipe 11 is connected to the upper end of a vertical leg 15 of a hydraulic closure 16 the under end of which leg 15 dips under the water surface in a drain pipe belonging to a conventional street-sewer system. Due to the vacuum maintained in the system, a column of drain water is maintained in leg 15, which column has a height depending on the vacuum generated by a fan 18 connected to the suction pipe 12.
The inlet valves 8 and 9 are, for example, of the kind shown in FIGS. 2, 3 and 4 having a chamber 20 presenting two opposite side walls 21, 22 of stiff material and two side walls 23, 24 of flexible material and a top and a bottom wall of flexible material. In the top wall perpendicular to the stiff side walls 21, 22 there is a slot 25 extending upwardly in FIG. 2 between two flexible lips 26 forming a part of the top wall of chamber 20. The lips 26 extend upwards to form, via a transition sec- .tion 28 of flexible material, a short inlet pipe 27. An outlet pipe 29 is connected to pipes 2 and 3, respectively, (FIG. 1) and communicates with the interior of chamber 20 via an opening in the bottom wall of chamber 20.
Altemately, the valves 8, 9 can be designed as shown in FIG. 5. This valvecomprises a tubular member 30 of flexible material having two opposite wall portions permanently deformed to sealingly engage each other. This valve is, to a certain extent, impervious for air but not for water and the sealing action of the walls 30 is amplified by the vacuum maintained in the outlet pipe 29.
The valve 10 of the water-closet is a manually operated membrane valve, known per se. If a water-closet of conventional type is used having an outlet provided with a hydraulic closure, it is possible, however, to utilize an automatically operated valve of the type shown in FIGS. 2 to 5 instead of the manually operated valve 10. In order to obtain outside air injection into pipe 4, this pipe is provided with branch pipe 32 connected close to the valve 10. Eventually a further branch pipe 34 is connected to pipe 32 connecting the interior of the water-closet with the interior of pipe 32. The outside air flows into the pipe 32 through an air-throttling nozzle 33 attached to pipe 32. A further air-throttling nozzle 35 is attached to the top of the vertical pipe 1 and other such nozzles may be arranged at different points along the house-pipes 2, 3, 4, if necessary.
The operation of the drain system is as follows:
A permanent vacuum of about 700 mm. water column is maintained in the system by the fan 18, in which case the height of the water column in the hydraulic closure 15 is about 700 mm. Air flows into the nozzles 33, 35 and pipe 34 through the pipes l, 2, 3, 4, 11 and 14 to the fan 18.
If water is supplied to the normally closed valve 8, for example, the lips 27 open slightly, assisted by the vacuum in chamber 20 which tends to bend the flexible walls 23, 24 inwardly. The operation of the valve shown in FIG. 5 is similar to that described in connection with the valve shown in FIGS. 2-4 although no vacuum assistance of the opening of the valve is obtained.
The surprising effect of the valves permitting water including solid particles in the water to pass the valves in spite of the fact that the lips 26 and walls 30, respectively, are firmly pressed against each other under the influence of the pressure difference existing between the exterior and the interior of the valves seems difficult to explain. An explanation is, however, that a film of water or moisture always adheres to the inner walls of the valve including the wall portions so that they sealingly engage each other, which film transmits the vacuum to the under side of a film of water supplied to the valve and covering the opening of the slot between the sealingly engaging wall portions of the valve. If a large quantity of water is supplied, the valve rapidly opens as soon as the initial film has been sucked into said slot.
Drain water supplied to pipes 2, 3 and 4 is rapidly transported towards pipe 1 when the inlet valves 8, 9 and 10, respectively, are opened and with reduced velocity when the inlet valves are closed. Especially when the drain water includes a high content of solid particles it is important to inject air into the pipe. The air inlet arrangement permits emptying of the system when all inlet valves are closed and thus in creases the capacity of the system. Moreover, the air inlet arrangement effectively eliminates the necessity of accelerations and retardations of big water columns or water pistons and has a damping effect to pressure variations in the system.
The drain water arriving in pipe 1 l is normally split up into drops carried together with solid particles by the air stream. After removal of the air through the water separation tank 13 the drain water including solid particles falls down through the vertical leg 15 of the hydraulic closure 16 into the conventional street-sewer system 17.
What is claimed is:
l. A sanitary drain system for a building comprising,
at least one soil pipe having an outlet end,
at least one waste pipe connecting a waste water drain to said soil pipe,
an inlet valve through which said waste pipe is connected to said soil pipe,
means providing a hydraulic closure at the outlet end of said soil pipe,
mears connected to said soil pipe for maintaining a vacuum therein,
means adjacent the inlet end of each waste pipe for admitting throttled outside air to said waste pipe.
2. The drain system of claim 1 in which each said inlet valve is responsive to the vacuum in said soil pipe to remain closed in the absence of waste water in said drain at the inlet side of said valve,
each said valve further being opened in the presence of waste water in said drain at the inlet side of said valve.
3. The drain system of claim 1 in which each inlet valve comprises flexible walls having inner surfaces which communicate with the valve interior and bear against each other,
said flexible walls bearing tightly against each other to provide an air-tight seal in the presence of a vacuum applied to the outlet end of said valve,
only the interior portions of said flexible walls communicating with the interior of said valve.
4. The drain system of claim 2 in which each said valve comprises a tube formed of a flexible material and formed to have opposite wall portions which sealingly bear against each other.
5. The drain system of claim 2 in which said valve comprises a partition wall between the inlet and the outlet of said valve, said partition wall being provided with a transverse slot dividing said partition wall into two flexible lips bearing against each other, the outlet of said valve forming a chamber which under the influence of the vacuum at the outlet end of said valve has a tendency to collapse in the longitudinal direction of said lips.