Water flushing device

A pressurized-tank water flushing device has a hydraulically controlled flushing valve operated by a control valve for selectively applying a pressure differential to an actuating piston, one face of which is permanently subjected to the tank pressure, and the other face either to the water supply, or to atmospheric pressure. The actuating piston has a hollow shank acting as a slide valve which switches on the supply of water to the tank when the flushing valve closes, and cuts off the supply of water to the tank when the flushing valve opens.

The invention relates to water flushing devices of the type in which the 
tank contains a volume of compressed air above the water level. 
It is known that such pressure-operated flushing devices are advantageous 
in having a reduced water consumption. Generally, it is possible to clean 
a W.C. bowl with about half the water required by a conventional flushing 
device. 
An object of the invention is to provide a pressure-operated flushing 
device of very reliable operation and which can be manufactured at 
relatively low cost. 
To this end, a pressure-operated flushing device according to the invention 
comprises a hydraulic actuator controlling a tank-flushing valve. The 
actuator includes a piston functioning as an actuating member. The piston 
is movable as a function of the pressure in two distinct spaces, a first 
space located below the lower face of the piston and submitted to the 
pressure within the tank, and a second space located above the upper face 
of the piston and submitted selectively by a control valve to two 
pressures, an upper pressure able to move said member to close said 
flushing valve against the action of a spring biasing the flushing valve 
to an open flushing position, and a lower pressure which allows said 
flushing valve to open under the combined action of said spring and the 
pressure in said first space.

The flushing device shown comprises a tank 1 of plastic material and only a 
part of which is shown. Tank 1 is fluid-tightly closed so as to be able to 
trap a quantity of compressed air above the water level. 
The control of filling of tank 1 takes place by a valve 2 in the base of 
the tank. Water is delivered by a pipe, now shown, to a union 3 and the 
flow of water is controlled by a valve cone 4 cooperating with a seat 5. 
Cone 4 is moved by a differential piston formed in two parts 6 and 7 
separated from one another by a membrane 8. The pressure in tank 1 acts on 
part 7 of the differential piston by means of a membrane 9. When this 
pressure is sufficient (i.e., reaches a given value), part 7 pushes cone 4 
against seat 5, against the action of a biasing spring 10 tending to hold 
the valve cone 4 in the open position. Washers 10' of given thickness are 
placed to set the tension of spring 10, and consequently the desired 
limiting pressure in tank 1. 
The outflow of the water under pressure contained in tank 1, via a flush 
pipe 15, is controlled by a flushing valve 11 carrying an elastomeric 
joint 12. This joint 12 is able to bear against a seat 13 at the inlet of 
a sleeve 14 to which the flush pipe 15 is connected. 
Valve 11 has substantially radial ducts 16 connecting the tank 1 to a well 
17 of the valve which communicates with a bore in a sleeve 18 supporting 
the valve. Sleeve 18 is slidably mounted in a hollow shank 19 of a piston 
20 slidably mounted in a cylinder 21. The rest position of piston 20 and 
sleeve 18 is limited by abutment shoulders 22 and 23 of shank 19 and 
sleeve 18 respectively and by a spring 24 which holds these shoulders in 
contact. 
When the piston 20 is not subjected to hydraulic pressure on its faces, it 
is held in the position shown in FIG. 1 by a spring 25. In this position, 
its hollow shank 19, which forms a hydraulic distribution slide valve, 
closes a duct 26 which is connected to the union 3 when cone 4 is open. 
This duct 26 is provided in a support plate 27 on which cylinder 21 is 
secured by thermoplastic welding or by an adhesive. The support plate 27 
also has a duct 28 which places the inside of cylinder 21 under piston 20 
into communication with the inside of tank 1. The hollow shank 19 of 
piston 20 has radial holes 29 leading into a groove 30 on the outer face 
of shank 19. 
The space 31 situated in cylinder 21 above piston 20 communicates by means 
of a pipe 32 with a three-way control valve 33. In its rest position shown 
in FIG. 1, valve 33 places pipe 32 into communication with a pipe 34 which 
is branched to the duct 26 for delivering water into tank 1. When the 
manually-actuable plunger 35 of valve 33 is in the position shown in FIG. 
3, pipe 32 is placed into communication with a pipe 36 leading into sleeve 
14, i.e., to a location at atmospheric pressure. The plunger 35 of valve 
33 is biased to the position of FIG. 1 by a spring 37. 
Of course, pipes 32, 34 and 36 may have any desired length, so that the 
control valve 33 may be placed on the tank 1 or at another location, for 
example embedded in a wall or in the floor. 
Operation of the described device is as follows: 
When the tank 1 has been emptied, the various parts are located in the 
position of FIG. 1. The filling water delivered by union 3 can flow into 
duct 26 and pipe 34, since cone 4 is in the open position. However, the 
filling water cannot flow through duct 26 which is closed by the shank 19 
of piston 20. The water thus flows through pipe 34 and valve 33 into pipe 
32 and space 31 and comes to exert its pressure on the piston 20 which it 
pushes down against the action of spring 25. The downward movement of 
piston 20 closes seat 13 by means of valve 11 and, as shown in FIG. 2, the 
downward movement of piston 20 can continue against the action of spring 
24 which allows sleeve 18 to slide in shank 19. 
The continued downward movement of shank 19 brings groove 30 to face duct 
26 whereupon the filling water can pass through holes 29 into the hollow 
shank 19 and sleeve 18 and enter tank 1 via the radial ducts 16 of valve 
11. The outlets of ducts 16 are in the immediate proximity of the bottom 
of tank 1 and the ducts 16 are directed substantially "tangentially" to 
this bottom, so that filling of the tank 1 takes place very silently. 
During filling, the air trapped in tank 1 above the water level is 
compressed so that the tank is placed under pressure. When the pressure 
reaches the value set by spring 10, it causes a displacement of the 
differential piston formed by parts 6 and 7, against the action of spring 
10, and closes valve cone 4. The device is hence ready for a flushing 
operation. Even in the case of stoppage of the supply of water, the tank 1 
remains under pressure because the cone 4 is closed and acts as a 
retaining valve. 
To actuate flushing, the plunger 35 of valve 33 is moved against the action 
of spring 37. When plunger 35 is depressed, its lower end closes pipe 34 
and the pipe 32 is connected to atmospheric pressure by pipe 36. The 
pressure in space 31 above piston 20 consequently drops, and the piston 20 
is pushed up by the combined action of spring 25 and the pressure of the 
water in tank 1, which pressure is transmitted by the duct 28 in support 
plate 27. As the piston 20 moves up, its shank 19 comes to obturate duct 
26 and valve 11 is then lifted from its seat 13 to evacuate the 
pressurized water from tank 1 via sleeve 14. 
To flush a small quantity of water, for example to damp the W.C. bowl 
before use, the user will rapidly release plunger 35 of control valve 33, 
so that after a small quantity of water has been delivered, the piston 20 
is pushed down by the pressure re-established in pipe 32. 
To completely clean the W.C. bowl, the user maintains a pressure on plunger 
35 of valve 33 so that tank 1 may completely empty itself. The water is 
flushed violently since its initial pressure may, for example, be between 
2 and 3kg/cm.sup.2. 
When the tank is completely emptied of water, the various parts are once 
more in the position of FIG. 1. The inside of tank 1 is in communication 
with the external air via sleeve 14 since the valve 11 is in the open 
position. It is hence ensured that after each complete emptying, the tank 
1 is in the desired conditions for satisfactory operation. 
The described device is very advantageous since, with the exception of the 
membranes/and springs, all of the parts can be in injection-molded 
thermoplastic resins. Moreover, the pressure exerted on the valve 11 is 
substantially constant, which avoids any excessive stressing of joint 12 
and, at the same time, any risk of unwanted outflow. Furthermore, no 
internal leaks are to be feared as the pressure is equal in all parts of 
the mechanism. 
Of course, numerous modifications may be provided. For example, the piston 
20 could be replaced by another form of hydraulic actuator such as a 
membrane device. Likewise, it would be possible to provide a mechanism, 
sensitive to movement of the flushing valve and acting on a valve 
controlling the delivery of water into the tank, to replace the 
arrangement on shank 19 which acts as a slide valve.