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| Vacuflush, How it works? |  |
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| Vacuum Operation levels & Leak Rates |  |
| Help to locate vacuum leaks |  |
| Keep Vacuum tester new |  |
TOILET TECHNOLOGY COMPARISON
Marine Toilet Technology:
• A traditional marine toilet consists of a toilet bowl with a pump or pumps to suck seawater in and flush wastewater out.
• Variations of marine toilets range from simple manual units with double acting piston pumps to more complex jet systems which employ a high pressure stream of water at the base of the bowl to blast its contents overboard.
• The use of seawater as a flushing medium in any marine toilet is a drawback because of microscopic organisms, which are sucked into the toilet intake hose.
• While the boat stands idle for a few weeks (or even days in hotter climates), these microorganisms die and decompose resulting in powerful sulfurous malodors when the toilet is flushed again.
• Seawater is also highly corrosive and frequently causes a build up of calcium carbonate inside hoses.
• Use of large amounts of water to transport waste material is also a major drawback if it is connected to a holding tank.
• The holding tank capacity becomes filled primarily with flush water and very little waste, resulting in too little space for a sufficiently large holding tank on smaller boats.
• Several other exotic concepts in marine toilet technology have also been developed and offered in recent times, but the further a device functionally varies from a household toilet, the less desirable it becomes.
• Clean flush water and simple, odor-free operations are essential to meeting the expectations of modern boat owners.
• The key benefits of the VacuFlush system are its extremely low usage of both flushing water and electrical current.
• The average flush of a VacuFlush toilet consumes a little more than a pint of water (0.5 L).
• Using fresh water is a practical alternative to seawater because consumption per day per person is in the range of just one gallon per five flushes.
• Sulfurous malodors and the corrosive and caking characteristics of salt water are eliminated.
• If used with a holding tank, the total usable capacity of the tank can be increased by up to 400%..
Vacuflush technology
Principle of Operation:
A vacuum toilet uses the pressure differential between the normal outside atmosphere pressure and an artificially created internal vacuum. This pressure differential can propel waste over a horizontal distance or upward.
What kind of Vacuum level use Vacuflush toilets:
The SeaLand system is designed to operate at sea level in terms of outside atmospheric pressure and 10-inches of mercury (inHg) vacuum pressure. Other systems are designed to operate at very high altitudes (Boeing 757) or at much higher levels of vacuum (cruise ship systems).
SeaLand’s VacuFlush system also incorporates a funnel with a 1-inch (25mm) orifice in the base of the toilet. This orifice causes material leaving the bowl to fragment because of the very high velocity of the in rushing air. This orifice also prevents any foreign material larger than 1-inch (25mm) from entering the system.
Watch this demo video:
What is a vacuum?
A vacuum is a space which has no matter in it. Strictly speaking, there is no such thing as an absolute vacuum, because all space contains some matter. In practice, we speak of a vacuum as a space from which most of the air or gas has been taken. But this is only a partial vacuum.
The important thing about a vacuum is that it can be a very useful emptiness. For example, if we create a partial vacuum in any space, water or any other fluid may enter it. We make use of this principle in drinking lemonade through a straw. We do not pull the liquid up through the straw. Instead, by sucking on one end of it, we take out some of the air that is in the straw. The air outside exerts pressure on the liquid and forces it up and through the partial vacuum in the straw.
Atmospheric pressure: In the air we breathe, there are about 400 billion billion molecules of gas per cubic inch (25 billion billion per cubic centimeter). The force on a surface produced by the weight of the air above it is called atmospheric pressure. Thus, atmospheric pressure decreases with height. The standard value of atmospheric pressure at sea level is one atmosphere or 14.7 pounds per square inch or about 100 kPa per square meter.
Returning to our example of drinking lemonade through a straw, what is the maximum vertical distance the straw can be used to lift the lemonade, no matter how much suction is applied to the upper end? It is the equivalent of the weight of the atmospheric gases pushing on the surface of the lemonade. Therefore, if one psi will raise a column of water (lemonade) 2.3- feet (0.7m), the maximum height that water can be sucked up a straw is 33.8-feet (10.3m). 2.3 X 14.7 = 33.8.
How vacuum is measured?
One can determine the level of vacuum stored in a vessel by connecting it to a vertical pipe at least 33.8-feet long with one end of the pipe in a container of water and the other connected to the vessel storing the vacuum. By measuring how high the water is sucked up the pipe, one can determine the level of vacuum stored in the tank. For instance, if the water column was sucked up 17- feet (5.2m), we can determine the level of vacuum in the container to be –7.4 psi or about one half atmosphere of vacuum pressure.
It would be more convenient to use a more dense liquid for measurement to avoid having to carry around long sections of pipe. Mercury is the most dense liquid and, therefore, commonly used for this purpose. The chemical symbol for mercury is Hg. One will frequently see vacuum measurement expressed in inches or millimeters of mercury (inHg or mmHg). See the table on the next page which lists several different scales for vacuum measurement.
Psia versus psig:
These are abbreviations for pounds per square inch absolute (psia) and pounds per square inch gage (psig). Some gages used for measuring pressure are set with the zero point at the equivalent of one atmosphere or 14.7 psi of pressure. In other words, these gauges measure vacuum starting with zero at one atmosphere of pressure. This type of pressure measurement is referred to as psig. Other gauges are set differently, zero is actually set at a level which would be the equivalent of an absolute vacuum. These readings are referred to as psia. By comparison, 10 inHg of vacuum is the equivalent of about –5 psig or +9.7 psia.
Vacuum Operation levels & Leak Rates
On / Off Levels
The VacuFlush pump is controlled by a pressure differential switch mounted in the vacuum tank or generator which stores a volume of vacuum pressure in the same manner that an accumulator tank or an air compressor stores positive air pressure. The differential switch is pre-set at the factory to turn on the pump when the vacuum level drops below 8 inHg and turns off the pump when it reaches 10 inHg of vacuum.
Vacuum Operation levels & Leak Rates
Inherent in the design of any system which utilizes vacuum energy is the possibility of leaks. One advantage of vacuum is that leakage is air into the system not water out of the system. The leak rate of a VacuFlush system is the time it takes for the vacuum level to drop off from 10 to 8 inHg. A leak rate of three hours is an acceptable level of system integrity. Always determine leak rate before starting troubleshooting procedures. Frequent running is generally only a problem if the noise of the running pump is disturbing the boat owner. A running pump can be especially disconcerting if it automatically starts in the middle of the night.
Audible Vacuum Leaks:
A leak which causes the pump to run once an hour is generally audible, providing background noise is minimal. Shutting down all other shipboard equipment and carefully listening to each major component can be the most efficient way to find a leak.
Help to find Vacuum leaks
Vacuum Tester
SeaLand has developed a simple tool to assist in identifying the location of vacuum leaks. The vacuum tester consists of a vacuum gauge and a cone-shaped plug. Inserting the plug in the inlet of the vacuum tank or generator isolates the toilet from the system. In this way a troublesome leak can easily be located in either the toilet, vacuum generator, vacuum tank or vacuum pump.
Order only the Vacuum Tester (part number 530002) or as part of the complete system maintenance kit (part number 310228).
VACUUM TESTER USAGE
The vacuum tester can be used to check for leaks in the vacuum toilet, vacuum tank or generator and for worn duckbill valves in the vacuum pump. Follow these steps:
- Vacuum Toilet (A)
- Turn off water supply. Insert plug into funnel inside toilet base through open flush valve. Wait until pump stops and compare leak rate time to previous leak rate. (Note if pump does not shut down after five minutes, the leak is probably down stream from this point).
- Turn off water supply. Insert plug into funnel inside toilet base through open flush valve. Wait until pump stops and compare leak rate time to previous leak rate. (Note if pump does not shut down after five minutes, the leak is probably down stream from this point).
- Vacuum Tank (B)
- Checking at the inlet of the vacuum tank effectively splits the system to quickly isolate the location of a vacuum leak. Wait until pump stops and compare leak rate as above.
- Vacuum Pump (C)
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Due to the small volume of the pump inlet, the vacuum gauge will fluctuate radically with every revolution of the pump. Insert the plug end of tester into the pump. Allow it to operate for two to three minutes. Shut off power to pump. Note position of vacuum gauge indicator. (It will probably not show more than 7 or 8 inHg.) If there is no movement in the indicator after ten minutes, the valves are probably sealing satisfactorily and do not need to be changed.
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Digital vacuum tester
Instructions and Operation
The SeaLand Digital Vacuum Gauge (part no. 530003) features a measuring range of 0" to 30" Hg of vacuum. It is ideal for measuring the vacuum levels in a SeaLand® VacuFlush® toilet system.
The accuracy of the gauge is ±1% of full scale, or ±.3" at 68°F to 72°F (20°C to 22°C).
Temperature has an effect on the gauge – about ±.1% of full scale per °F. This would be .03" Hg per °F. If the gauge temperature changes 10°F between readings, the gauge could change as much as .3" Hg due to this temperature change. For highest accuracy, allow the gauge temperature to stabilize if it has been stored in a very cold or very hot environment. Small temperature changes will have minimal effect on the gauge reading.
The Digital Vacuum Gauge operates on a replaceable 9-volt battery.
Digital Vacuum Gauge Operation
To determine system leakage rate and time between pump cycling:
- Turn off water to toilet.
- Open the toilet’s fl ush ball and insert the rubber plug
into the 1" orifi ce in the bottom of the base. The
vacuum pump will be running. - After the vacuum pump shuts off, allow the digital
gauge to stabilize for a minute. - Push the button on the gauge, and record the vacuum
reading to the nearest hundredth of an inch (.01"). - Keeping the rubber plug in the 1" orifi ce, wait 15 minutes,
and then record a second vacuum reading. - Subtract the two readings and record the drop in vacuum.
Caída del nivel de vacío (en 15 min.) Intervalo entre ciclos de bombeo
0,2" Hg (incorrect) 2,5 h
0,15" Hg (acceptable) 3,0 h
0,10" Hg (good) 5,0 h
0,05" Hg (very good) 10,0 h
Maximum acceptable level of leakage
To identify vacuum leakage point:
1. Turn off water to toilet.
2. Open the toilet fl ush ball and insert rubber plug into 1" orifi ce in the bottom of the base (Fig. 1). If there is no vacuum leak at this point, the leak is above the
1. orifi ce in the base:
• Check for a crack in the base, funnel, or fl ush ball.
If there is a vacuum leak, go to next step.
3. Remove inlet hose to vacuum generator and insert rubber plug in the inlet fi tting (Fig. 2).
If there is no vacuum leak at this point, the leak is between the toilet and the vacuum generator:
• Check the hose and clamps between the toilet and the vacuum generator. If there is a vacuum leak:
• Check duckbill valves for foreign objects or cuts.
• Check spin nut and fi tting between pump and vacuum tank.
How to keep the vacuum tester new
We have received many requests to see if there was a possibility of a kit to replace the rubber cone.
This piece does not exist as a replacement, but now we can supply it.
Order Information : The replacement kit Ref 311161
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It consists of a rubber cone and hose, as seen is this photo:
