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Publication numberUS3425438 A
Publication typeGrant
Publication dateFeb 4, 1969
Filing dateOct 4, 1965
Priority dateOct 4, 1965
Publication numberUS 3425438 A, US 3425438A, US-A-3425438, US3425438 A, US3425438A
InventorsFay O Suffron
Original AssigneeAmerican Metal Prod
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Antisyphon device
US 3425438 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

Feb. 4, 1969 0', SUFFRON 3,425,438


4 7 mar/14 United States Patent 3,425,438 ANTISYPHON DEVICE Fay 0. Suifron, Los Angeles, Calif., assignor to American Metal Products Corp., Los Angeles, Calif., 21 corporation of California Filed Oct. 4, 1965, Ser. No. 492,540 US. Cl. 137-216 Int. Cl. E03c 1/10 This invention relates to an improved air gap unit which is a device having the purpose of preventing backflow or syphoning through a drain line or other line. An exemplary form of the invention is described herein in connection with dishwasher drain plumbing.

The water from a dishwasher is discharged into the sewer line, and to do this, customarily the water from the dishwasher is pumped up to a level to allow it to flow into the drain pipe of a sink, for example. It is quite possible for the drain pipe of the dishwasher to effectively form a syphon as a result of which the water of the sink can be syphoned back into the dishwasher. This is definitely to be avoided. It is in such an environment as this that the air gap device of this invention is useful although it can be used in various other environments.

To avoid backflow or syphoning, it is necessary that at some point within the drain or discharge line, for example, a dishwasher and sink waste pipe, air must be permitted to enter in order to prevent any syphoning action from occurring. Attempts have previously been made to isolate the dishwasher and the main drain line. These generally in the prior art have not been entirely successful and have been deficient in various respects. Quite commonly such known devices would fail to prevent backflow or syphonmg.

A primary object of this invention is to provide an improved air gap unit or device which is simple, elfective and which overcomes the deficiencies of prior art devices.

Another object of the invention is the provision of a drain gap unit or device which is easily and quickly installed and which is easy to maintain.

Another object of the invention is to provide a drain gap unit or device which is extremely easy and economical to fabricate and produce.

Another object is to provide an improved air gap device wherein an inflow tube terminates in a position near an air gap or opening in a cap on an outflow tube with an arcuate baflle interposed between the end part of the inflow tube and the air gap.

Further objects and additional advantages of the invention will become apparent from the following detailed description and annexed drawings, wherein:

FIG. 1 is a diagrammatic view of a dishwasher and sink having the invention embodied therein;

FIG. 2 is a cross-sectional view of a preferred form of the invention;

2 Claims FIG. 3 is a sectional view taken along the line 33 of r FIG. 2; and

FIG. 4 is a sectional view taken along the line 44 of FIG. 2.

Having reference to FIG. 1, this figure shows a typical arrangement of a dishwasher and sink with a preferred form of the invention embodied therein, whereby the dishwasher is able to drain to the sink waste line. The dishwasher has a pump 13 at the bottom of it. The dishwasher has a drain line 15 which is raised to an elevation higher than the drain line 17 of the two sinks 19 and 20. Numeral 23 designates a garbage disposal unit installed below the sink, and this may be that type of device which grinds foods finely enough to be discharged through the drain line 17. The drain line 25 connects the air gap device or unit 27 to the garbage disposal unit 23 which drains through a line 29 to the drain line 17.

The device 27 is attached to the sink at the drain board 30, as may be observed. The device 27 provides an air gap to prevent any syphoning action occurring and it also serves the function of reversing the flow of water in the line. FIG. 2 is a cross-sectional view of the complete unit, and FIG. 3 is a cross-sectional view of the cap part of the unit by itself. The unit includes an inflow pipe or conduit 34. This pipe is connected to the line 15 in FIG. 1. Its end part, as designated at 35, is at a level above the sink drain board 30. This inflow conduit extends upwardly through a side wall 36 of a larger outflow pipe 37 which has a bend in it at 38 which is adjacent to the position at which inflow conduit 34 enters it. The outflow conduit 37 is connected to the drain line 25, as shown. The outflow conduit is threaded as shown and it passes through an opening 40 in the drain board 30 and is mounted in the drain board. On the bottom side of the drain board there is a nut 42 threaded onto the outflow conduit 37 with a flexible sealing washer 43 between this nut and drain board.

The functions of the air gap unit or device are provided by the assembly described including a cap or unit as identified by the numeral 44. This may be in the form of a single device molded or otherwise fabricated from plastic and having a unique design and configuration for accomplishing its purpose. It has an upward taper as shown at 45 and a slightly enlarged skirt 46 at the lower part having an extending flange 48. The skirt is internally threaded and it threads onto the threads at the upper end of the outflow pipe 37. Interposed between the flange 48 and the drain board 30 is a flexible sealing washer 50 which completes the seal between the drain board and the air gap device or unit.

Referring to the gap or unit 44, it is circular and it has an opening in a side wall as designated at 52 which is the air gap which provides communication of air necessary to break or counteract any syphoning effect. The position of the opening 52 is adjacent to the upper end of the inflow line 34 as will be referred to again presently. As the water enters through the inflow line 34, it is directed against the inside surface of the top of the cap 44 and is reversed in direction. However, water is prevented from splashing out. of the opening 52 which opening provides the air gap as pointed out which prevents syphoning action. Depending downwardly from the inside surface of the cap 44 is a baffle member 55 having an arcuate portion 56 which conforms in curvature to the cap member 44 itself. The curved portion 56 of the baflie 55 is adjacent to the opening 52. At the ends of the curved portion 56, the baffle 55 has straight portions 60 and 61 which are attached to or may be integral with side walls of the cap 44. The cap unit, as pointed out, may be made of plastic or other comparable material by means of known fabricating processes. FIG. 2 shows the position of the baflle 55 relative to the opening 52 and the top 35 of the inflow pipe 34. The straight side portions 60 and 61 of the baffle member 55 have cut away or bevelled bottom corner edges designated at 63 and 64 in FIG. 3. These cut-aways are in a very definite position with respect to the air gap opening 52 and the top end of the inflow pipe 34. These cut-aways or cut-outs are at a level above the bottom edge of the opening 52 and they also extend to a level above the top edge 35 of the inflow pipe 34. In this way there is assured a positive air gap which will prevent any syphoning action, tests having demonstrated that the syphoning cannot take place. As shown and described, the baflie 55 is between the opening 52 and the top 35 of the inflow pipe 34, and it is adjacent to the inflow pipe. Its circular arcuate curvature conforms to the curvature of the inflow pipe 34 as well as in the curvature of the cap 44.

The device as described has been found to be very effective for its purpose. It serves its purpose very admirably of reversing the flow of water and preventing any clogging up of the line as well as providing the positive air gap to prevent syphoning.

From the foregoing those skilled in the art will observe that the invention as described herein achieves and realizes all of the objects and advantages as set forth in the foregoing as well as having many additional advantages which are apparent from the detailed description.

The foregoing disclosure is representative of a preferred form of the invention and is to be interpreted in an illustrative rather than a limiting sense, the invention to be accorded the full scope of the claims appended hereto.

I claim:

1. An antisyphon device comprising means providing an air gap chamber having an opening providing an air gap, inlet conduit means communicating with said chamber, outlet conduit means communicating with said chamber, said inlet conduit means having a discharge opening spaced from said opening providing an air gap, means extending between the said discharge opening and an end of said air gap chamber, said means being constructed to form a barrier extending across said air gap chamber in a position between said discharge opening and said air gap opening, the said means including an arcuate portion having a radius of curvature substantially the same as that of said discharge opening and said barrier means having sufficient extent as to extend below said air gap opening, said air gap chamber being circular in cross-section and having a top wall and side walls, its opening being in a side Wall thereof, said barrier having an arcuate portion adjacent said air gap opening, said arcuate portion being connected to and extending downwardly from the top wall of said air gap chamber, and including flat portions positioned along a diameter of said air gap chamber connecting the edges of said arcuate portion to the side walls of said air gap cham her and supporting the arcuate portion within the air gap chamber.

2. A device as in claim 1 wherein said barrier has cutaway portions at opposite sides of its lower edge, the lower edge of said air gap and the upper end of said inlet conduit means being at a level which is intermediate with respect to said cut-away portions.

References Cited UNITED STATES PATENTS 2,704,083 3/1955 Low 137216 X 3,155,106 11/1964 Baron 137-216 2,287,534 6/1942 Powers 137-216 3,183,923 5/1965 Henrikson 137216 OTHER REFERENCES American Metal Products Co., Inc., Air Gap (Antisyphon Device) 1, 17, 1964.

WILLIAM F. ODEA, Primary Examiner.

DENNIS H. LAMBERT, Assistant Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2287534 *Mar 19, 1941Jun 23, 1942Gen ElectricVacuum breaker
US2704083 *Oct 1, 1951Mar 15, 1955Gen ElectricInlet fitting for dishwashers and the like
US3155106 *Aug 13, 1962Nov 3, 1964Us Brass CorpDishwasher drain airgap
US3183923 *May 11, 1961May 18, 1965Robert E HenriksonAir gap antisyphoning device
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3929149 *May 23, 1974Dec 30, 1975Robert Manufacturing CompanyBackflow preventor for automatic dishwashers
US4237919 *Jun 8, 1979Dec 9, 1980General Electric CompanyDishwasher inlet air gap
US4399832 *May 20, 1981Aug 23, 1983The Mundo CorporationAir gap assembly
US4454891 *Mar 9, 1982Jun 19, 1984Emerson Electric Co. (H & H Precision Products Division)Air gap drain module for use in a reverse osmosis system
U.S. Classification137/216
International ClassificationE03C1/10
Cooperative ClassificationE03C1/102, E03C1/10
European ClassificationE03C1/10A, E03C1/10