Baths – closets – sinks – and spittoons – Wash receptacles – With drain
Reexamination Certificate
2001-03-22
2002-05-28
Fetsuga, Robert M. (Department: 3751)
Baths, closets, sinks, and spittoons
Wash receptacles
With drain
C004S321000, C004S431000, C004S668000
Reexamination Certificate
active
06393635
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to waste disposal systems and, in particular, to a commercial aircraft galley waste disposal system.
2. Description of the Prior Art
In commercial aviation, it is necessary to dispose of unwanted fluids and solids such as human waste and food waste. Disposal of human waste is accomplished with the use of toilet systems such as conventional vacuum toilet systems. Since about the early 1980's, it has become common to use vacuum toilet systems in large commercial aircraft. These vacuum waste systems typically include a toilet bowl for collecting waste, a waste holding tank, a vacuum pump, and a valve system for placing the toilet bowl in communication with the waste holding tank. A rinse valve controls the introduction of rinse water into the toilet. The system is typically controlled by an electronic controller.
The problem of disposal of food waste has not yet been fully addressed. During in flight operation of commercial aircraft, a large quantity of food and beverage leftovers can accumulate on an airplane, the volume depending on the number of the passengers and the duration of the flight. This leftover waste can come in the form of solids, liquids, and/or a mixture of the two, called “slurry.” Thus, the handling of this waste is an issue, particularly on longer flights having many passengers. During such flights, holding the waste in the aircraft galley (food preparation area) on the trays and in the carts in which the food and beverages are served for the duration of the flights is: 1) impractical because of the relatively large quantity of food stored and served; 2) unsanitary; and 3) can be unsightly.
Currently, most commercial aircraft are equipped with galley sinks. However, these sinks are intended for the disposal of fluid waste only as they are connected to small diameter drain lines, ranging from about one half to one inch in diameter, and terminating at the aircraft drain mast for exhaustion to the atmosphere. Unfortunately, such sink systems are unable to dispose of slurry and solid food waste products.
In response to this problem, flight attendants have often been instructed to dispose of solid and slurry food wastes into the toilets which are located near the galleys. Conventional aircraft vacuum toilets are effective for disposing of such food waste products for a number of reasons. First, they are connected through much larger lines, typically two inches in diameter, to waste holding tanks. Further, conventional aircraft vacuum toilet systems transfer waste from the toilet bowl to the waste holding tanks via a differential pressure action, thereby ensuring immediate and complete evacuation. In particular, the air pressure in the toilet bowl is at cabin pressure (which is pressurized for the safety and comfort of those on board), while the drain line is maintained at a much lower air pressure from a source of vacuum. This source is typically either a vacuum pump or the atmospheric pressure outside of the airplane, which is very low at cruising altitudes of thousands of feet above sea level. This differential reaches approximately 8.5 p.s.i, at an altitude of about 35,000 feet. Thus, when the flush valve separating the two atmospheres is opened, a strong vacuum action results and powerfully draws the contents of the toilet bowl into the waste holding tanks.
While disposing food waste in aircraft toilets is effective for its removal from the cabin, several problems and disadvantages have been identified. First, it can be quite unsanitary for a flight attendant to enter into a lavatory to dump food waste into a toilet bowl while working with food in the galley. For example, given the time demands on flight attendants, there is a possibility, and perhaps even a likelihood, that they will fail to wash their hands each time they exit the lavatory. Second, requiring attendants to dispose of food wastes in toilets is both inconvenient and inefficient. The process requires the attendant to carry the container holding the waste from the galley to the lavatory, open the door, bend down to the level of the toilet bowl and pour the waste into the bowl, taking care that it does not spill anywhere but in the bowl. This may have to be repeated several times until all or enough of the food waste is flushed down the toilet. Further, using a toilet bowl requires, of course, that one be available. However, availability of the lavatories is subject to their occupancy by the passengers. It would be inefficient for an attendant attempting to complete the task of cleaning up after a meal to have to wait until a toilet became available. Additionally, requiring flight attendants to use toilets for the disposal of food waste appears unprofessional and can be distasteful to the flying public.
One approach to the general problem of food waste disposal during in flight operation of commercial aircraft, which has come to the inventor's attention, has been a proposed design for a galley sink system based closely upon existing aircraft vacuum toilet designs. Thus, such a sink system would include a drain line having a much larger diameter than conventional galley sinks and would operate on the same differential pressure, or vacuum, theory used by conventional vacuum toilet designs.
While generally effective for disposing of solid, liquid and slurry food wastes, implementing one of the conventional vacuum toilet designs into a galley sink system is unsatisfactory for numerous reasons. First, these designs do not account for the potential for clogged drain lines. In particular, if and when the drain line of a conventional vacuum toilet becomes clogged, flush cycles may continue to operate and rinse water may continue to be introduced into the bowl despite the lack of pressure differential between each side of the flush valve (i.e. between the bowl and the drain line). Thus, the system is enabled until the stoppage is identified by an individual and the problem is corrected. Under this condition, the toilet bowl itself could even eventually begin to fill with a mixture of rinse water and black, or human waste, water. However, due to sanitation concerns and health and safety regulations, this situation would be unacceptable in a galley sink environment, where the sink bowl may not become contaminated with either used sink water, called grey water, rising from the clogged sink drain line, or black water rising from the aircraft's main drain line.
A second problem concerns the potential for large objects being dropped or flushed into the drain line. Certain objects often found in a galley, including chopsticks, cutlery, and large bones, while too large to be disposed of by a galley sink system, could inadvertently enter into the sink bowl, and, because of their elongate and relatively narrow shapes, pass the sink bowl's waste disposal outlet, enter into the drain line and become lodged therein. Other objects, such as solid food waste that would normally pass through the system could then become engaged with the lodged object, eventually leading to a clogged condition. Even worse, the large object could find its way into the flush valve assembly and cause the flush valve to malfunction or break. Thus, such an obstructed object must be promptly removed from the drain line. However, with conventional drain line designs, its removal would be quite burdensome, requiring disassembly of the galley sink drain line. Further, the lodged object may not be identified until only after one of the aforementioned, or other, resultant problems arise. Thus, a need exists for a galley sink system that prevents such an object from becoming lodged in the drain line while permitting other food wastes to enter into the line for disposal.
Another problem with the earner galley sink design relates to noise. A loud flushing sound is created when the flush valve opens and the differential pressure across it forcefully draws the waste down the drain. The lid, or shroud, of the earlier galley sink design, based closely on conventi
Christie Parker & Hale LLP
Fetsuga Robert M.
MAG Aerospace Industries, Inc.
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