[0001] The invention refers to a WC cistern (fig. 1) consisting of the shell of an air vessel
which meets requirements for strength as well as economy of space and aesthetics.
The cistern includes an airbag and its air valve, an injector with a non-return valve
on its intake and an outlet valve leading to the toilet bowl.
[0002] There are two basic methods of toilet flushing:
1. The various types of gravity cisterns which are fed through a valve and include
a float to regulate water level.
2. The various types of pressure valves which must be fed by a pipe of an appropriate
diameter from the water supply system.
[0003] The advantages of this invention are:
1. The system is fed by an economical half-inch pipe.
2. There is no need for a float or cut-off valve.
3. It is not necessary to elevate the cistern to exploit gravity.
4. Since the water is ejected into the bowl under pressure. flushing results are better
and less water is consumed.
[0004] The WC cistern (figure 1) with airbag and injector is comprised of the shell (1)
which is cylindrical, spherical etc. in shape and conforms to materials strength requirements
but can also be fitted in the space in an aesthetically pleasing manner.
[0005] Inside the air vessel we place an elastic airbag with a valve suitably protruding
from the shell. On the bottom side of the air vessel (shell) we have created a hole
for connecting the outlet pipe and valve. The valve may be fitted to the cistern shell
or to its discharge pipe. Valves are shown in figures 2 and 3 respectively.
[0006] In addition, the hole is large enough to allow the empty airbag to fill up with air
when required.
[0007] Also fitted to the shell of the air vessel is the connection with the water supply,
via the injector, through the city's or ship's water mains. The injector has a non-return
valve for uptake of atmospheric air.
[0008] We prepare the system for operation by filling the airbag (2) through its valve (3)
with air under 02-03 atmospheres of pressure, more or less, depending on what is technically
desirable.
[0009] We close the discharge valve (6) and open the water supply valve via the injector
(4). Mains water, usually under 3-5 atmospheres of pressure, will pass through the
injector (4) and fill the cistern (1), at the same time sucking in atmospheric air
and pushing it into the air vessel.
[0010] The water that flows in occupies the bottom part of the space, compressing the air
which enters through the injector, as well as the air inside the air bag in the top
part of the space. The inflow of water will continue until the pressure of the compressed
air is equal to the pressure of the water, which is 3-5 atmospheres. The non-return
valve (5) which lets air in through the injector is already closed, preventing water
from flowing outward. The more air pressure we have in the airbag (2), the less water
will enter, and vice versa.
[0011] By now opening the discharge valve (6), the water, compressed by the air, will gush
out into the bowl, with a steadily decreasing outflow, according to the principle
P1 V1 = P2 V2 = constant. To be sure, the system may be operated with the airbag only,
or with the injector only, but using both ensures more foolproof operation.
[0012] The system's discharge valve (figures 2 and 3), fitted either on the air vessel (cistern)
or on the outlet pipe, operates smoothly, in full harmony with the principles of operation
of the system. The valve (figures 2 and 3) consists of two plungers (1 and 2), fitted
with rubber rings (3) to make them watertight. The plungers are attached to a rod
(4), at a suitable distance from each other. The rod (4) protrudes above the cover
(5) and is connected to a knob (6) to pull the rod (4) and the plungers (1 and 2),
which are held down by a spring (7), so that the lower valve/plunger (2) rests in
the base (8) which has been suitably formed at the bottom of the jacket (9) of the
valves (fig. 2 and 3).
[0013] The jacket (9), at a suitable distance above the lower valve/plunger (2) and below
the pressure equalising plunger (1) has slots (10) through which the water flows out
towards the toilet bowl when the knob (6) is pulled, raising the rod (4) together
with the plungers (1 and 2). Plunger (2) uncovers the outlet slots (10) and the water
flows out into the bowl.
[0014] The valve operates in the following manner: When the cistern has emptied and is at
zero pressure, the tension of the spring (7) pushes the rod (4) together with the
plungers (1 and 2) downwards, and the valve/plunger (2) closes the outlet slots (10).
[0015] The cistern begins to fill with water from the pipe (11) and pressure gradually builds
up in the space. The pressure acts upon equal surfaces of the plungers (1 and 2) above
and below, so that the force exerted on the knob (6) by the pressure is zero.
[0016] Thus when we pull the knob (6) upward, initially we overcome the downward force exerted
by the tension of the spring, but by pulling the knob we also uncover the slots (10)
and then the pressure is also exerted on the bottom surface of the plunger (2). Therefore
the resultant of the forces acts in an upward direction and the valve is kept open
until the cistern empties and the pressure within it falls. Then the spring (7) pushes
the rod (4) downward, the plunger/valve (2) seals off the slots (10), and the cistern
again begins to fill from the pipe (11).
[0017] The valves pictured in figs. 2 and 3 are of the same type, but the valve in fig.
2 can be incorporated in the system, whereas the valve in fig. 3 may be fitted to
the outlet pipe in any position the user desires.
1. Pressure cistern (fig. 1) for flushing toilet, with an airbag and an injector. Features
include a watertight air vessel (1) suitably designed to provide durability, efficiency
and good utilisation of space.
One or more elastic airbags (2) inside the shell (1) with an air valve protruding
from the shell (1) through which air under 02-03 atmospheres of pressure, more or
less depending on what is technically desirable, can enter or exit the elastic airbag
(2).
Fitted to the pipe connected with the city's or ship's water supply is an injector
(4), before the point where the water enters the air vessel (1). On the injector's
intake (4) we place a non-return valve (5) through which atmospheric air is sucked
when the air vessel (1) fills with water. This air enters the air vessel (1) under
the same pressure and at the same speed as the water and occupies the top part of
the air vessel (1) and the space around the elastic airbag (2), which shrinks into
the upper space of the air vessel, compressed by the rising level of the water.
When the difference in pressure between the water and the air vessel decreases sufficiently,
the vacuum in the uptake of the injector (4) is reduced and the non-return valve (5)
closes, preventing the water from returning outward.
2. According to the specification, another feature of the pressure cistern (fig. 1) is
an outlet valve (fig. 2) incorporated in the shell, and a valve (fig. 3) suitable
for fitting on the outlet pipe. Both valves work in the same manner.
The main parts of the valve are: The cylindrical jacket (9) with slots (10), the base
(8), the cover (5), the rod (4), two plungers/valves (1 and 2) for equalising pressure
and watertightness, with rubber rings (3), a spring to shut off the flow of water
to the bowl (7) and a knob to pull the rod upwards and begin the flushing action (6).
3. The pressure cistern (fig. 1) for flushing a toilet in accordance with specifications
(1) and (2) can be of any shape, in harmony with materials strength and utilisation
of space.