US2792125A - Septic tank - Google Patents

Description

May 14, 1957 J. l. GALLAGHER 2,792,125

SEPTIC TANK Filed Nov. 4, 1952 L f E- T1 1 1 2a 15 as -|2- as -17 I l 3 IN V EN TOR.

SEPTIC TANK James I. Gallacher, Costa Mesa, Calif., assignor to Teddy Gene Worley, Costa Mesa, Califi, doing business as Woriey Company Application November 4, 1952, Serial No. 318,647

1 Claim. (Cl. 210-533) This invention relates to a pre-fabricated septic tank and has as an object the provision of a concrete tank which may be manufactured in advance rather than poured at the site of use, and which is so constructed as to be adaptable to many variations of conditions of installation.

Another object of the invention is -to provide a prefabricated septic tank which is inexpensive to manufacture and which requires a minimum of labor to install.

A specific object of my invention is to provide a septic tank formed of two halves so shaped that they are easily molded and may be nested for storage and transportation and which are much easier to handle individually than a unitary tank of the same capacity.

Other more detailed and specific objects of my invention will be pointed out as the following specification proceeds or will be apparent from the description of a preferred embodiment when considered with the accompanying drawing, in which Fig. l is 'a top plan view of a septic tank accordingto my invention;

Fig. 2 is a vertical longitudinal sectional view on the line of section 22 of Fig. 1;

Fig. 3 is a vertical transverse sectional view on the line of section 3--3 of Fig. 1; and

Fig. 4 is a plan view of the upper half of my tank, upset and viewed looking into its open side.

Having reference to the details of the drawing, my invention comprises a septic tank formed of two halftanks 6 and 7, of which one half-tank 6 is the bottom portion of the tank and the other half-tank 7 is the cover portion. Both half- tanks 6 and 7 are manufactured by being cast from cementitious material, such as concrete, and to facilitate casting and to permit the use of rigid molds which may be used repeatedly, as well as for other reasons hereinafter appearing, the half tanks are of isosceles trapezoidal form in both longitudinal and transverse cross section, although of course being hollow. That is, the bottom half-tank 6 has a narrow elongated flat bottom wall 8, outwardly flaring side walls 9, and outwardly flaring end walls 10, providing a wide rectangular open side at the rim 11. The upper half-tank or cover 7 likewise has a narrow elongated fiat top wall 12, outwardly flaring side walls 13 and outwardly flaring end walls 14 so that the rim 15 may meet and match with the rim 11 in upper and lower relationship. The rims 11 and 15 are preferably provided with mortise 16 and tenon 17 or equivalent matching shoulders so that they may be pointed accurately with respect to each other and sealed by grouting.

The isosceles trapezoidal form of the half- tanks 6 and 7 not only facilitates casting but it facilitates storage, transportation, handling and installation. Large numbers of tanks may be cast in advance of use and nested for storage in a small storage space. A truck of moderate size can transport nested half-tanks which when assembled make a tank of greater capacity than any prefabricated unitary tank which the truck could hold, and the nited States Patent 0 half-tanks may be lifted onto the truck and removed therefrom individually. The narrow bottom and top walls 8 and 12 make it easy to roll a half-tank on its side or to slide it. In digging a pit to receive the tank, the pit walls may be sloped at the same angle as the side walls and end walls 9 and 10, so that the pit walls do not cave in during digging but subsequently render firm support to the lower tank 6 without fill-in. When a completed tank has been installed and covered over with earth, the trapezoidal form of the upper half-tank '7 permits it to endure much greater pressure from above, as the top wall 12 is narrow and distributes pressure through the sloping walls 13 and 14 to the rims 11 and 15. The tank may therefore be placed in an area of heavy, even vehicular, trafiic.

The usual interior arrangement of septic tanks is to provide an outlet conduit near the top of the tank which establishes a water-line, an inlet conduit just above the water line, and a baffle between the inlet and outlet conduits extending above the water line to prevent passage of floating matter toward the outlet and having a port below the water-line to permit passage of clear fluid toward the outlet after sludge has decomposed and settled. Surface baffles are sometimes placed near the inlet to induce vertical currents and prevent strong horizontal surface currents. My improved septic tank provides for such conduits and battles but in an improved manner which facilitates their installation and permits selectivity in their placement.

In casting the :cover half-tank '7, insert cores are placed in the mold to cast a plurality of recesses in the end walls 14 and in the side walls 13 adjacent the end walls. These recesses form weakened wall portions which may be knocked out selectively to provide ports for the necessary conduits. As shown in Fig. 2, knock-out ports 26 are cast in the cover 7, preferably one in an end wall 14, and one each adjacent thereto in the side walls 13, at such a level that the lower rims of the ports will establish a water line 21 at a desired level. These knock-out ports 20 will be ports available selectively for an outlet conduit 22. At the opposite end of the cover 7, knockout ports 23 are similarly cast in the end wall 14 and side wall 13, but at a slightly higher level so as to be entirely above the water-line 21. The knock-out ports 23 will be ports available selectively for an inlet conduit 24.

Additional inserts are placed in the mold for the cover 7 to provide opposed grooves 25 on the interior surfaces of the side Walls 13 adjacent to, but inwardly of, the knock-out ports 20. The grooves 25 serve to hold a transverse baflle 26 extending from below the water-line 21 to a sufficient height above the water-line to screen the ports 20. As the side-walls 13 are sloped, the ballle 26 may be firmly wedged into the grooves 25 so that it will not drop out, no bolts, studs or retaining elements other than the sloping grooves 25 being required to retain it.

In like manner, grooves 27 are formed at the opposite end of the cover 7, to wedge and hold a transverse bafile 28. As the ports 23 which are to be screened by the baflle 23 are placed a little higher than the ports 20, so likewise the grooves 27 and battle 28 extend a little higher than the grooves 25 and bafile 26, but also extend below the water line 21.

At positions between the grooves 25 and 27, inserts are placed in the molds to cast opposed grooves 30 in the side walls 13 of the cover 7, extending from the rim 15 nearly to the top wall 12. Similar grooves 31, coplanar with the grooves 30, are cast in the side walls 9 of the bottom half-tank 6. The grooves 31 extend from the rim 11, where they join the grooves 30 when the tank is assembled to the bottom wall 8. When the tank is being assembled a baffle 32 is wedged in the grooves 39 and 31. The baffle 32 has a port 33 and otherwise vertically divides the interior of the tank into two interior compartments 34 and 35 from the bottom wall 8 to well above the water-line 21. 1

To afford access to the interior of the tank, man-hole openings 36 are cast in the top wall and are closed by covers 37.

Obviously the bottom half-tank 6 may be placed in a suitable pit and the cover 7 may be placed upon it as shown in the illustrations or reversed end for end. Usually, if the bafile 32 is so placed as to make larger and a smaller interior compartment, the end of the cover 7 containing the inlet ports 23 will be placed over the larger compartment, so that there may be more storage capacity for incoming sludge, but that is not always necessary. In whatever way the cover 7 is placed upon the bottom 6. the arrangement of the ports 23 and 2t) permits the conduits 24 and 22 to enter and to withdraw from the tank at the ends thereof or from either side, thereby giving a large range of selectivity in laying the infall and outfall conduit systems and in connecting these systems to the tank. Fluid entering the compartment 34 through the inlet conduit 24 will be forced downward by the baffle 28 to deposit its heavy contents. Light sludge will rise to the surface but will be prevented by the bafile 32 from entering the compartment 35 until it has disintegrated and settled. Relatively sludge-free fluid will pass through the port 33 into the compartment 35 and a large part of any sludge remaining in suspension will be prevented by the baifie 26 from entering the outlet conduit 22.

As modifications of the above-described embodiment of my invention are possible within the scope and spirit of my invention, I desire to have that scope interpreted as fully commensurate with the appended claim.

I claim:

A septic tank comprising two substantially like-shaped half-tanks each of isosceles trapezoidal form in both longitudinal and transverse cross-section and having rims of like perimeter at their greater trapezoidal bases adapted to be joined in upper and lower relationship, opposed divergent sides of said half-tanks having grooves for the reception of baflles, and a plurality of transversely extending baffles held in said grooves, at least one of said bafiles extending from the lower of said half-tanks into the upper of said half-tanks, the grooves of said upper halftank holding said bafile against upward displacement in positions below the top of said half tank in which they support said sides, said grooves terminating below the top of said half-tank and said bafiles being wedged in said grooves.

References Cited in the file of this patent UNITED STATES PATENTS

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