Patent Application
20130167293
The present invention relates to a flush toilet which can be continuously used without supplying additional water from outside.
Toilets are essential in order to maintain hygiene of an environment where humans live. In order to maintain high standards of living where the population density is high, flush toilets are indispensable, instead of toilets of the type which are eventually simply dumped into the environment. But in rural communities which are far from cities and cannot afford to construct a sewage system, toilets are often used having a sewage treatment tank in which waste is decomposed utilizing microorganisms. It is also being considered to use sewage as flush water for flush toilets so that flush toilets can be installed in areas where it is difficult to construct a water supply system.
For example, Patent document 1 discloses a heating/evaporation type toilet system including a flow type waste tank in which waste from a toilet bowl is crashed, an evaporation oven in which the crashed waste is evaporated, two deodorizing pipes for deodorizing water vapor from the evaporation oven, and a filtering tank in which water is recovered from the water vapor in the flow type waste tank, wherein a large amount of waste is circulated to soften it. In the evaporation oven, the waste is heated until it disappears. That is, by crashing waste in the waste tank and then heating it in the evaporation oven, nothing remains in the oven (see paragraph [0015] of Patent document 1). Since water vapor is deodorized in multiple stages, foul odor is substantially reduced.
Patent document 2 discloses a circulation type flush toilet system including a biological decomposition tank in which waste is biologically decomposed, a filtering tank in which the biologically decomposed water is separated into solid and liquid components, and a decoloring tank in which the water separated in the filtering tank is decolored, wherein the water decolored in the decoloring tank is used as flush water, while water overflowing the decoloring tank is returned to the biological decomposition tank. This toilet system further includes an evaporation tank in which a portion of the filtered water is evaporated. The water vapor thus produced is condensed back into water and returned to the biological decomposition tank (FIGS. 1 and 2 of Patent document 2). Blowers are connected to the filtering tank, biological decomposition tank and evaporation tank, respectively, to supply compressed air into these respective tanks (see e.g. [0020] of Patent document 2). An electric power pump is used to draw water from the biological decomposition tank into the filtering tank. The pump is controlled by upper and lower float switches so that the water level can be finely adjusted (see paragraphs [0021] to [0024] of Patent document 2). This system is a large-scale system which can be used not only as a toilet but also as an industrial sewage treatment system (see paragraph [0064] of Patent document 2).
Patent document 3 discloses a temporary toilet unit including a urinal and a toilet bowl. If this toilet unit is used in a civil engineering site, the toilet bowl is almost exclusively used for defecation and thus is less frequently used than the urinal. Thus, by biologically decomposing the waste from the toilet bowl, it is not necessary to empty the tank storing the waste from the toilet bowl for a prolonged period of time (see paragraph [0010] of Patent document 3). On the other hand, sewage from the urinal is aerated in an aeration tank and then evaporated by heating with a heating device so that a very small amount of solid content remains. This makes it possible to extend the intervals between maintenances of this toilet unit to about one year (paragraph [0009] of Patent document 3).
While the toilet system disclosed in either of Patent documents 1 and 2 can sufficiently deodorize and decolor waste produced, it is large in size. Washing and replacement are considered necessary for the deodorizing pipes and the filtering tank of Patent document 1. This shortens the intervals between maintenances. The toilet system of Patent document 2 also requires a plurality of treatment tanks, in which the respective water levels have to be adjusted. Thus, the treatment mechanism of this toilet system, including treatment tanks, is inevitably larger in size than the toilet body itself. There are a large number of component parts that need periodical maintenance. It is therefore troublesome and time-consuming both to install this toilet system and to maintain it. For these reasons, neither of these toilet systems can be installed in areas where once the toilet system is installed, it has to be left unattended for a long period time, such as on riverbeds, campsites, mountain trails, etc. These toilet systems are therefore cannot be practically used as temporary toilets in view of the difficulty in storage, transportation and operation. These toilet systems may be used in civil engineering sites, because there is heavy traffic of people in civil engineering sites. But even in such places, because the above toilet systems are heavy and large in size, locations where they can be installed are limited.
The temporary toilet of Patent document 3 can achieve its expected advantage only if it is used mostly by men. If a large number of women use this toilet, the waste from the toilet bowl dramatically increases, thus shortening the intervals between maintenances. Since sewage is simply evaporated and not reused as flush water, flush water has to be supplied from outside. Thus, this toilet cannot be installed where it cannot be connected to a water supply system.
An object of the present invention is to provide a temporary flush toilet which is compact in size and thus is easily transportable, and which can be installed where the toilet cannot be connected to a water supply system and no frequent maintenance is possible.
In order to achieve the object, the present invention provides a temporary toilet comprising a toilet bowl, a flush water tank which keeps flush water to be supplied into the toilet bowl, a sewage tank which keeps sewage discharged from the toilet bowl and decomposes the sewage by microorganisms, a water vapor separator capable of separating water from a gas containing water vapor which has been evaporated in the sewage tank, an exhaust pipe through which the gas is guided from a top of the sewage tank to the water vapor separator, and a water supply pipe through which the water separated in the water vapor separator is supplied into the flush water tank.
Only up to about 80% of flush water used to flush the toilet bowl can be evaporated and reused as flush water, and the remaining water is discharged into the atmosphere in the form of water vapor. Thus, if only flush water were evaporated and recycled, the total amount of water stored in various parts of the toilet according to the present invention would decrease gradually. But according to the present invention, since sewage containing not only flush water used to flush the toilet bowl but also human waste, which contains a large amount of water, is evaporated and reused, the total amount of water stored in the various parts of the toilet according to the present invention can be maintained at the same level, without the need to receive water from outside such as from a public water supply system or from a water supply tank car. This is the most important feature of the present invention.
Another important feature of the present invention is that sewage stored in the sewage tank is biologically decomposed in the sewage tank and also evaporated in the sewage tank. Thus, the sewage tank also serves as a biological decomposition tank and a water vaporization tank. Since the sewage tank according to the present invention serves the above-mentioned triple purposes, the toilet according to the present invention is simpler in structure, less likely to malfunction, and smaller in size, than the devices disclosed in Patent documents 1 and 2. For smoother and quicker biological decomposition of sewage, the interior of the sewage tank is preferably kept at 25° C. or over. As long as enough water is stored in the sewage tank, a sufficient amount of water can be evaporated without the need to heat sewage in a separate oven or furnace. Since the sewage tank can keep a sufficient amount of water, it is possible to maintain the total amount of water kept in the entire toilet at a sufficient level.
Microbial decomposition itself produces heat. But a heater may be added to further heat the sewage tank. Further, means may be provided for supplying gas for aeration into the bottom portion of the sewage tank to accelerate decomposition by aerobic bacteria and to agitate sewage, thereby preventing formation of masses in sewage.
When human waste is decomposed by microorganisms at a temperature range of 25 to 30° C., particularly at a temperature range of 28 to 30° C., odor will not be particularly strong. Gas containing water vapor evaporated from the sewage in the sewage tank is trapped in the water vapor separator to separate water from the gas, and the gas deprived of water is released into the atmosphere. Thus, the toilet according to the present invention produces far less odor than the temporary toilet disclosed in Patent document 3, in which water vapor from sewage is directly released into the atmosphere. Since temporary toilets, including the one according to the present invention, are installed at places where humans do not live on a permanent basis, slight odor from the temporary toilet according to the present invention will hardly stay or accumulate to such an extent as to offend people around the toilet, but will easily diffuse even by light winds.
In order to provide electricity for the water vapor separator, pump for flushing the toilet, heater, aerator, etc., the temporary toilet according to the present invention may further includes solar cells and a battery for storing the electricity generated by the solar cells. With this arrangement, it is not necessary to connect the toilet according to the present invention even to the public electricity network, which makes it possible to use the toilet as a completely stand-alone toilet unit.
The temporary flush toilet according to the present invention can be installed at any location where there is neither a water supply system nor a sewage system, because the toilet according to the invention can be used for an indefinite period of time without the need for any willful supply of water from outside. Once installed, this toilet is virtually maintenance-free. But if it is desirable or necessary, water such as rainwater may be supplied from outside, for example, if a large amount of flush water is consumed during a short period of time.
Specifically, the toilet according to the present invention can be installed on riverbeds, in campsites, along mountain trails, in or by beach houses, and in other places where there are usually no water supply system and no sewage system. The toilet according to the present invention can also be installed in civil engineering or construction sites or any other places where conventional temporary toilets are usually installed. When installing the toilet according to the present invention in one of these places, and when removing it, it is not necessary to connect and disconnect the toilet to and from a water supply system or a sewage system. Thus the toilet according to the invention can be easily installed, removed and/or relocated to another place.
Now the embodiments are described in detail.
First, the temporary toilet of the first embodiment is described with reference to
The flush water tank 11 is mounted in the toilet bowl body 104. Flush water used to flush the toilet bowl 18 after use is stored in the flush water tank 11. A foot pump chamber 12 is provided in the toilet bowl body 104 at its front right corner so as to be completely isolated from the flush water tank 11. A foot pump 13 is mounted in the foot pump chamber 12. A foot pedal switch 14 protrudes from the front side of the toilet bowl body 104. When the foot pedal switch 14 is depressed, the foot pump 13 is activated to suck flush water through a pump suction pipe 15 extending from the foot pump chamber 12 into the flush water tank 11, and then feed the thus sucked flush water into a pump feed pipe 16. The flush water in the pump feed pipe 16 is injected into the toilet bowl 18 through a nozzle 17. The injection angle of the nozzle 17 is adjusted such that the injected water circulates around the surface of the bowl 18 before dropping into the hole of the bowl 18 so that the entire bowl 18 can be washed with a minimum amount of water.
When the foot pedal switch 14 is depressed and flush water is injected, a bottom lid 21 provided at the bottom of the toilet bowl 18 also opens. Thus, the flush water used to wash the toilet bowl 18 drops into a waste storage tank 22, together with waste. The waste storage tank 22 is partitioned from the flush water tank 11. The letter A in
Sewage B, which is organic, in the sewage tank 24 is decomposed by microorganisms, while its water content gradually evaporates. Air containing water vapor C produced in the tank 24 is supplied through an upwardly extending air exhaust pipe 31 into an air pressurizing pump 32 in the control booth 102, where the air pressurizing pump 32 pressurizes the air containing water vapor C to reduce the amount of saturated water vapor, thereby allowing the water vapor C in the air to be condensed into water. The water is separated in a water vapor separator 33 and then supplied back into the flush water tank 11 through a distilled water pipe 34 so that the water is reused as flush water D.
Dry exhaust air E which has been separated from the water vapor C and thus is low in water content is discharged to outside through a discharge tube 35 by means of an exhaust fan 36 provided at an upper portion of the toilet unit 100.
The water vapor separator 33 may be an ordinary dehumidifier, a cooling air compressor, or a dry separator of the cyclone type. Alternatively, the water vapor separator may be of the type which contains porous particles of e.g. silica gel which can adsorb water and includes means for releasing the adsorbed water by heating. But the separator 33 may be of any other type which can separate water from air and take out the thus separated water. In view of the object of the present invention, however, a water vapor separator is preferably selected which is sufficiently compact in size and consumes less electricity.
Most part of water held by this temporary toilet exists in the sewage tank 24. The sewage tank 24 occupies substantially the entire interior of the base 103 to ensure a sufficiently large contact surface area of water and air. With this arrangement, water in the sewage tank 24 evaporates naturally to a certain extent, without the need to heat the tank 24 to such an extent as to cause excessive evaporation. Also, because the tank 24 is large in volume, microbial decomposition occurs in a large volume of water in the tank 24. The sewage tank 24 thus serves the triple purposes as a microbial decomposition tank, evaporation tank, and water storage tank. This makes it possible to minimize the volume of the entire temporary toilet.
Most temporary toilets are mainly used only during the daytime or only during the nighttime. Thus, water accumulated in the sewage tank 24 during the busy hours is evaporated, separated from air, and returned to the flush water tank 11 during the less busy hours. The water thus returned to the tank 11 can be used during the next busy hours.
The sewage tank 24 includes a mechanism which accelerates microbial decomposition of organic matter. This mechanism is described with reference to
This mechanism includes a blower pump 41 in the control booth 102, and a blower diffuser tube 42 extending from the blower pump 41 and uniformly covering the entire bottom surface of the sewage tank 24. Aerating air is supplied from the blower pump 41 into the blower diffuser tube 42 and is discharged through a large number of discharge holes formed in the underside of the tube 42, thus agitating, while aerating, the sewage B in the tank 24 from below. Thus, aerating air supplies oxygen into sewage B, prevents organic solid substances from remaining on the bottom of the tank 24, and crashes organic solid substances into small pieces, thereby accelerating decomposition of organic solid substances.
A branched heater 43 is further provided in the sewage tank 24 which is submerged in sewage B and capable of uniformly heating the sewage B. By heating the sewage with the heater 43, organic substances can be decomposed at a practically acceptable speed even during the wintertime, when the ambient temperature is low and thus microorganisms tend to be inactive. In order to keep the heat produced by the heater 43 in the tank 24, its inner surface is covered with a heat insulating material 44, or such a heat insulating material 44 is embedded in the wall of the tank 24.
However, excessive heating of the sewage B may slow down, rather than accelerate, microbial decomposition, and also may cause excessive evaporation of sewage B exceeding the capacity of the water vapor separator 33. Thus, an electronic control unit 51 is used to optimally control the heater 43 according to various conditions. In particular, the control unit 51 includes a temperature regulator 52 which receives temperature information of sewage B from a temperature sensor 53 which is at least partially submerged in sewage B and which adjusts the output of the heater 43 based on the temperature information from the temperature sensor 53. Preferably, the temperature regulator 52 is configured to stop heating by the heater 43 when the temperature of the sewage B as measured by the temperature sensor 53 reaches or exceeds an upper threshold, which is set at a temperature between 25 and 30° C., and to restart heating when the temperature of the sewage drops below a lower threshold. With this arrangement, microbial decomposition of organic substances takes place in the tank 24 at a substantially constant rate throughout the year, so that the temporary toilet of the invention can be operated in a stable manner. Most preferably, the temperature of the sewage B is kept at 28 to 30° C. because at this temperature range, microbial decomposition is most active and odor is low.
The control unit 51 controls the output of the blower pump 41 too. Aeration may be carried out continuously or intermittently. If enough electric power is available, continuous aeration may be elected because continuous aeration more effectively prevents accumulation of organic solid substances on the bottom of the sewage tank 24, and allows stable supply of oxygen to microorganisms. If, on the other hand, saving electric energy is more important, aeration may be intermittently repeated each for the duration of several minutes, with the intervals of several minutes.
A floating water level sensor 61 is provided in the sewage tank 24, which is connected to a use prohibition display 62 through a switch. The use prohibition display 62 is attached to a portion of the door 105 where a person who tries to open the door 105 can never miss. When the level of the sewage B in the tank 24 rises to a predetermined point, which is typically the upper limit of the capacity of the tank 24, together with the floating water level sensor 61, the switch is adapted to be closed or opened, thereby changing the indication on the display 62 such that the display 62 now indicates that the toilet cannot be used (e.g. by distinguishing the sign “USABLE”, changing the sign “USABLE” to “UNUSABLE”, or turning off a green light and turning on a red light.
Behind the sewage tank 24, an overflow drain 64 is provided which allows overflow of sewage B if the toilet is used after the level of the sewage B has exceeded the upper limit of the capacity of the tank 24 and the indication on the display 62 has changed such that it indicates that the toilet is not usable.
If the level of the sewage in the tank 24, as detected by the floating water level sensor 61, falls below a predetermined lower limit, the control unit 51 is configured to turn off the heater 43, air pressurizing pump 32 and water vapor separator 33 to prevent any further reduction in water content in the tank 24 by stopping evaporation and escape of water vapor.
An air intake port 63 is formed in the floor of the toilet booth 101, which is located over the sewage tank 24. When air in the sewage tank 24 is sucked by the air pressuring pump 32, outer air can be introduced into the tank 24 through the air intake port 63. The air intake port 63 is sized such that no odor in the sewage tank 24 rises into the toilet booth 101 through the air intake port 63 while a negative pressure is being produced in the tank 24 by the air pressurizing pump 32.
Electric power may be supplied to this temporary toilet through electric wires as shown, or may be entirely from a separate solar cell panel (not shown). If a solar cell panel is used, it is necessary to additionally provide a secondary battery (not shown) such as a lead battery so that the blower pump 41, the heater 43, etc can be kept in operation on rainy days and during the nighttime. If a secondary battery is used, the control unit 51 may be programmed to compare the electric power stored in the battery with the power consumed by heater 43 and the blower pump 41 and to stop the aeration by the blower pump 41 if it is determined that the electric power stored in the battery is insufficient compared to the power consumption.
The second embodiment differs from the first embodiment in the following points too. First, since the sewage tank 24 is not located under the toilet bowl 18, and thus its inlet port is located at a point higher than the toilet bowl 18, a waste feed pump 73 is provided to pump up the waste in the bowl 18 to the inlet port of the tank 24. The pump 73 is directly connected to the center hole 74 of the toilet bowl 18. In particular, this pump 73 is provided instead of the waste storage tank 22 of the first embodiment at the same location where there is the waste storage tank 22 in the first embodiment. This pump 73 is preferably a power pump because it is considered difficult to pump up waste in the toilet bowl to a higher point with a manual pump.
The power waste feed pump 73 is activated, not all the time, but only when flushing the toilet bowl 18. Flush water in a flush water tank 11 is supplied into the toilet bowl 18 through a pump suction pipe 15 by a water suction pump 72 which is also a power pump.
The water suction pump 72 and the waste feed pump 73 are activated by depressing a switch button 71 provided in the toilet booth 101. In particular, when a user depresses the switch button 71 after use, the water suction pump 72 is first activated to inject flush water into the toilet bowl 18 through the nozzle 17, thus dropping any waste remaining in the toilet bowl 18 into its center hole. Simultaneously when the button 71 is depressed, or several second after the button 71 is depressed, the waste feed pump 73 is activated to pump up sewage dropped from the toilet bowl through a sewage discharge pipe 23 under pressure until it is fed into the sewage tank 24. The control unit 51 is preferably programmed to also control the pumps 72 and 73 in the above manner, to eliminate the need for an extra control unit.
Since the sewage tank 24 of the second embodiment is larger in size than the tank 24 of the first embodiment, and thus the surface area of the water in the tank 24 is larger, air supplied to the water vapor separator 33 of the second embodiment contains a larger amount of water vapor in order to more effectively and sufficiently condense such a large amount of water vapor into water, it is necessary to produce as high a pressure as possible in the water vapor separator 33. For this purpose, in the second embodiment, a compressor 75 is connected to the water vapor separator 33.
Some of the elements used in the second embodiment only may be used in the first embodiment too. For example, the compressor 75 may be used in the first embodiment too. Also, the water suction pump 72 and the switch button 71 for activating the pump 72 may be used in the first embodiment. In this case, the bottom lid 21 of the toilet bowl is operatively coupled to the switch button 71 so as to open temporarily when the button 71 is depressed.
A plurality of the toilet booths 101 of either of the first and second embodiments may be coupled together. In this case, the number of the sewage tanks 24 used with these toilet booths 101 may be smaller than the number of these toilet booths 101, which each include one toilet bowl 18. If a plurality of the toilet booths 101 of the first embodiment are coupled together, since the sewage tank 24 of the second embodiment has a larger capacity, the number ratio of the toilet booths 101 coupled together to the sewage tanks 24 used with these toilet booths may be from about 1:1 to about 4:1. Also, the toilet booth 101 and the control booth 102 may be integrated into a single toilet unit. In any of these arrangements, the entire structure is sufficiently compact in size, because the sewage tank or each of the tanks 24 serves the triple purpose as conventional evaporation tank, microbial decomposition tank and storage tank.
The toilet unit of either of the embodiment may further include at least one urinal. In this case, at least one toilet booth may include a plurality of urinals. The toilet bowls shown are of the Japanese style. But a western style toilet bowl may be used instead.
Flush water may be injected into the toilet bowl in a manner different from the manner shown. If the toilet is what is known as a light flushing type toilet, 400 to 500 cc of flush water is consumed per use. If a “Shatore” type (suction-and-pressurized-water-feed type) flush toilet (which is high in cleaning power) is used, the water consumption per use would be about twice that of a light flushing type toilet, and thus the throughput will be about twice.
The heater 43 may be provided, not in the sewage tank 24 as in the embodiments, but around the sewage tank 24 to heat the interior of the tank 24. Maintenance of the heater is easier with this arrangement. But from the viewpoint of heat efficiency, it is preferable to provide the heater 43 in the sewage tank 24 and further provide the insulating material.
Water may be supplied from outside. For example, rainwater may useful especially if the temporary toilet according to the present invention is installed outdoors and can be connected to neither a sewage system nor a water supply system.
In this modified embodiment, an open-topped rainwater storage tank 106 is provided on the rooftop of the toilet booth 101 of the toilet unit 100. A rainwater discharge port 81 is formed in the bottom of the tank 106. Rainwater collected in the tank 106 is fed downward through a rainwater supply pipe 82. A rainwater regulating valve 83 is provided in the rainwater supply pipe 82. Downstream of the valve 83, the pipe 82 has a rainwater supply port 84 through which rainwater is supplied into the flush water tank 11. A flush water level sensing float 85 is provided in the flush water tank 11. The control unit 51 determines whether the level of the flush water in the tank 11 is higher than an upper limit and lower than a lower limit, and throttles and opens the rainwater regulating valve 83 if the water level is higher than the upper limit and lower than the lower limit, respectively.
However, when such rainwater is supplied or if flush water is supplied into the flush water tank from outside in order to make up for temporary overuse of flush water, the total amount of water present in the various locations of the entire toilet unit 100 increases. The control unit 51 determines such total amount based on the positions of the floating water level sensor 61 and the flush water level sensing float 85, and if the control unit 51 determines that the total water amount is excessive, the control unit 51 reduces the amount of water supplied back into the flush water tank 11 through the water vapor separator 33, while temporarily increasing the amount of water discharged to outside.
Description is made of the specific amounts of water used in the various locations of each of the first and second embodiments. First regarding the first embodiment, 500 cc of water was flushed per use. The water content in the sewage tank 24 was 400 liters. The toilet was used about 60 times over a period of one week. 40 liters of waste was introduced into the sewage tank 24 per day on the average, and 30 liters of water was returned to the flush water tank 11 as flush water, whose capacity was 40 liters, per day on the average. 75% of the sewage introduced into the sewage tank 24 was recovered as flush water. During the one-week period, the total amount of water stored in various locations of the entire toilet unit 100 changed little.
Now regarding the second embodiment, 500 cc of water was flushed per use as in the first embodiment. The water content in the sewage tank 24 was 600 liters. The sewage tank 24 was used for two of the toilet booths 101 over a period of one week. 300 liters of water was returned to the flush water tank 11 per day. During the one-week period, the total amount of water stored in the various locations of the entire toilet unit 100 remained substantially unchanged.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2010/062101 | 7/16/2010 | WO | 00 | 3/25/2013 |
