Fig. 62. - Flask trap.
Fig. 63. - Clean-sweep trap.
After years of experimenting to produce a trap that would not syphon without venting, we find in use today a large variety of non-syphoning traps. Traps that will hold their seal against all practical forms of syphonic action, or other threatening features, have been made and used and serve the purpose for which they are intended. Various means to prevent the breaking of the seal of these traps are employed. While some depend on a ball or other kind of valve, others rely on partitions and deflections of various kinds. All of these perform the functions for which they are designed, yet the devices employed offer an excellent obstruction for the free passage of waste; therefore, in time, these traps become inoperative. It should be borne in mind that any traps with a mechanical seal or an inside partition are not considered sanitary. The inside partition might wear out or be destroyed and thus break the seal without the knowledge of anyone and allow sewer gas to enter the room. The mechanical device may also be displaced or destroyed, leaving the trap without a seal. If the trap were cleaned out often or examined occasionally, these traps could be used with a greater degree of safety. Some of the forms of non-syphon traps in common use are:
The Flask Trap, Fig. 62. This trap gets its name from its shape. There is an inside wall upon which the seal depends. This trap is like the bag trap, only the two inside walls of the pipe are combined into one. This wall should be of heavy cast brass, free from sand holes.
Clean Sweep Trap, Fig. 63. Some clean sweep traps are dependent upon an inside wall for their seals. They are made of 1⁄2-S, 3⁄4-S, and full S.
Fig. 64. - Mechanical-seal trap.
Fig. 65. - Standard "S" trap.
Fig. 66. - Bag trap.
Sure Seal Trap. The sure seal trap is designed to be non-syphoning. This trap also has an interior waterway. If this waterway leaks, the trap is unfit for use. If these traps are made as shown in the second sketch with the way inside of a larger pipe, it can be detected if the interior wall leaks.
Centrifugal Trap. The centrifugal trap is made similar to the clean sweep, except that the wall of the inlet pipe is entirely separate from the body of the trap. The inlet enters the body of the trap on a tangent, thus making the trap self-scouring which is a good feature.