Baths – closets – sinks – and spittoons – Flush closet – Bowl
Reexamination Certificate
1999-06-04
2001-05-08
Eloshway, Charles R. (Department: 3751)
Baths, closets, sinks, and spittoons
Flush closet
Bowl
C004S313000, C004S321000
Reexamination Certificate
active
06226807
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to vacuum toilet systems for aircraft, or other modes of transportation, and, in particular, to a system for reducing the amount of water consumed in the flushing of a vacuum toilet system.
BACKGROUND OF THE INVENTION
In the operation of commercial aircraft, it is necessary to provide on-board toilet facilities for use by the passengers and crew. These toilet facilities include vacuum toilets which presently require a specific amount of water to operate. However, an aircraft has only one limited water supply to meet all the water needs of the passengers and crew during the flight of the aircraft for drinking, food preparation, and other uses, as well as for use by the aircraft toilets. The amount of water stored in the aircraft is proportional to the trip duration and the number of passengers and crew that will be on-board the aircraft. Further, an ample amount of water is necessary to ensure the comfort of the passengers and crew. Unfortunately, a large amount of fuel is required just to transport the water supply which is a significant operational cost and decreases the efficiency of the aircraft. Therefore, a need exists to reduce the amount of water required to be flown by the aircraft to increase the overall efficiency of the aircraft and reduce operational costs.
As previously discussed, a significant amount of water is used during any given aircraft flight to operate the aircraft toilets. A reason for this is that when the toilet is flushed, no differentiation is made between flushing with solid matter due to defecation, and without solid matter, such as when a man stands and urinates. When the toilet is flushed, a standard amount of water is always used, approximately 8 fluid ounces, which assumes that solid matter, such as tissues and feces, is present. This large amount of water is necessary, when solid matter is present, because if a lesser amount of water is used, deposits will rapidly build upon the walls of the connecting conduits and critically impair the operation of the toilet system. However, when a male uses the toilet to urinate, substantially less water is required for flushing, and using a standard amount of water is excessive. The applicants estimate that approximately 45% of toilet use is by men standing and urinating resulting in a large amount of wasted water. Thus, aircraft currently carry a large load of unnecessary water, and correspondingly use a significant amount of unnecessary fuel to transport it. Therefore, it would be beneficial to have an aircraft toilet system that can vary the amount of flush water used depending upon whether the user has urinated or defecated.
An apparatus to control the amount of water used in the flushing of a toilet is described in U.S. Pat. No. 4,707,867 to Kawabe et al. The Kawabe apparatus utilizes a light beam sensor to detect whether a person has sat upon a toilet seat and uses this information to determine the volume of flush water to be used. The light beam sensor emits a light beam to a reflector which reflects the light beam back to the sensor creating an unbroken horizontal light beam path. The light beam sensor and reflector are located slightly above the toilet such that the light beam path is correspondingly located at the same position. Hence, when a user occupies the toilet, the light beam can neither reach the reflector nor be reflected back to the sensor, and the sensor thereby detects the presence of a user seated on the toilet. If the light beam is interrupted for greater than 90 seconds, the apparatus assumes the toilet user has defecated and utilizes a large amount of water, otherwise, the apparatus assumes the toilet user has urinated and utilizes a small amount of water. This apparatus uses a complicated electronic circuit having a plurality of different timers, which are used to time the interruption of the light beam and to control the timing of the opening and closing of a flush valve, thereby controlling the amount of water used. Although, this type of apparatus works well for its intended purpose, it has many drawbacks that would make it unsuitable for use in an aircraft toilet system.
A disadvantage of the Kawabe apparatus is that it is not suitable for use with aircraft because the aircraft lavatory system, as well as, the aircraft toilet system, would have to be substantially altered to accommodate it. For example, the light beam sensor would have to be mounted to one wall of the aircraft lavatory and the reflector would have to be mounted to another wall of the aircraft lavatory. Also, this type of light beam sensor is likely to become contaminated over time and require servicing. Furthermore, the use of a light beam sensor requires a complicated and expensive electronic circuit which has a plurality of different timers to time the interruption of the light beam. Lastly, another disadvantage of this apparatus, is that the sensor, the electronic circuit, and the associated wiring, could potentially cause electromagnetic interference with the existing on-board electronics of the aircraft. Therefore, the addition and integration of the Kawabe apparatus to an aircraft lavatory and toilet system could be costly and could potentially require additional testing and retrofitting to verify that it does not interfere with the already existing on-board electronics of the aircraft. Thus, the Kawabe apparatus is just not readily adaptable for use with an aircraft.
Accordingly, it should be appreciated that there is a need for a system for reducing water consumption in a vacuum toilet, suitable for use in an aircraft, that detects whether a toilet user has sat on the toilet seat, or has stood, and uses that information to control either a longer or shorter period of flow of rinse water allowing for a significant reduction in average water consumption.
SUMMARY OF THE INVENTION
The present invention provides a system for reducing the water consumption in a vacuum toilet on an aircraft by detecting whether a toilet user has sat on the toilet seat, or has stood, and uses that information to control either a longer or shorter period of flow of rinse water allowing for a significant reduction in average water consumption while maintaining current standards of toilet system cleanliness.
The system for the reduced water consumption vacuum toilet of the present invention includes a weight sensing device that is mounted to an aircraft toilet and is responsive to a weight applied to the bowl of the toilet. The weight sensing device detects that a toilet user is seated upon the toilet seat when it measures a weight applied to the toilet bowl. On the other hand, the weight sensing device detects that a toilet user is standing when the weight sensing device does not measure a weight applied to the toilet bowl. A flush control unit is connected to the weight sensing device and controls the amount of water utilized in the flushing of the toilet. When the toilet is flushed and the weight sensing device has detected that a toilet user has sat upon the toilet seat, the flush control unit commands that a standard amount of water be used. On the other hand, when the toilet is flushed and the weight sensing device has detected that a toilet user has stood, the flush control unit commands that a small amount of water be used thereby saving water.
In a preferred embodiment, the weight sensing device used is a pressure sensor which responds to the force applied to the toilet bowl by the toilet user sitting upon the toilet seat and generates a pressure signal that is proportional to the amount of force. A pressure derivation circuit is connected to the pressure sensor to receive the pressure signal. Upon receipt of the pressure signal, the pressure derivation circuit compares the pressure signal to a threshold value. The threshold value corresponds to a minimum weight required to be applied to the toilet bowl to indicate that a toilet user has sat upon the toilet seat. The pressure derivation circuit generates a standard flush signal if the pressure signal is greater th
Ratliff Robert G.
Rozenblatt Mike M.
Christie Parker & Hale LLP
Eloshway Charles R.
Mag Aerospace Industries, Inc.
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