Vacuum toilet
A vacuum toilet is a toilet in which wastewater and faeces, in contrast to flush or downpipe toilets, are not removed by gravity and / or water flow, but rather by means of negative pressure .
The toilet bowl has a small suction opening (approx. 32 mm in diameter) which is closed by a suction valve (electronically or pneumatically controlled). When the flushing process is triggered, water is first flushed into the toilet to be rinsed out and the suction valve opens approx. One second later. The pressure difference of −0.6 bar in the vacuum line "sucks" the waste water to be transported from the toilet into the vacuum line. The entire process is completed after about 2-3 seconds.
Areas of application
The vacuum or negative pressure drainage toilet has been used for decades in various areas such as shipbuilding, aircraft construction or the railroad industry. For some years now, vacuum toilets have also been used in buildings, e.g. B. the office buildings of KfW in Frankfurt am Main. Thanks to the system properties of vacuum drainage and the enormous savings potential in terms of water and wastewater costs, vacuum toilets can be seen as a future technology.
- Vacuum toilets are mainly used as on- board toilets in mobile installations such as ships and boats , airplanes and more modern railways . In addition, they do not connect the interior of an airplane or rail vehicle with the outside air, as a downpipe toilet would. In the case of mobile vacuum toilets, the waste-holding tank is usually vacuumed regularly, mostly by special vehicles that also refill the fresh water tank.
- Modern high-speed trains, such as B. ICE , TGV or the Japanese Shinkansen are nowadays only equipped with vacuum toilets, as these trains are equipped with pressurized cabins.
- Stationary vacuum toilets have long been installed within the radiological department of hospitals. A more recent area of application are energy-saving houses , where not only energy but also water should be saved: the flushing process of a vacuum toilet only consumes about one liter of water. In addition, the feces can be collected and discharged into a biogas or composting plant without serious dilution . The first vacuum toilets in energy-saving houses in Germany were installed in Vauban in 1998 .
- Vacuum toilets of a special design are used in manned space travel : Due to the prevailing weightlessness, flushing and downpipe toilets are ruled out, as they rely on gravity , while the "flushing" by means of an air stream works without problems. The toilet bowl is built in such a way that it seals tightly when the user takes a seat. For urinating, such toilets are usually also equipped with a small funnel on a hose. Adjustable brackets prevent the user from drifting around uncontrolled in the toilet cubicle.
Problems with users with greater body
Even though a tight connection of the user on the toilet bowl is important for vacuum toilets in spaceships, it is undesirable for vacuum toilets in gravity: A user can be "sucked on" to the toilet bowl while sitting while flushing if he is correspondingly full. In order to avoid this, the seats are designed in such a way that pressure equalization can take place (slots below the seat, relief opening in the front area).
Water and cost savings
Using a vacuum toilet saves water and thus energy costs. The following may serve as an example:
- A traffic building is frequented by approx. 5000 people every day. If a good 40% use a toilet and another 20% use a urinal, then the annual consumption of drinking water in conventional systems is 7665 m³.
- If you calculate with an average of 5.00 euros per cubic meter of water and wastewater charges, it is around 38,000 euros per year. With the technology of vacuum toilets, consumption and costs can be reduced by 84%.
Manufacturer
The largest manufacturers of vacuum toilets include EVAC GmbH (Wedel) and Dowaldwerke GmbH (Dippoldiswalde) in the railway sector and Monogram Systems from Carson, USA, CA and Apparatebau Gauting GmbH in the aviation sector. EVAC and Monogram belong to the French group Zodiac Aerospace .
Two companies in Germany also offer vacuum toilets for buildings and the associated systems: Vacusatec in Münster and Roevac in Hanau.
literature
- Journal: Swiss Railway Review ISSN 1022-7113 , 1996/12: Report with photos by Forrer Daniel, Meyer Leo, Renner Martin.
Web links
Individual evidence
- ↑ Archived copy ( Memento of the original from March 6, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
