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(11) | EP 0 584 031 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Vacuum toilet system for moving installations and civil constructions |
| (57) It comprises a valve (4) which connects each bowl with a waste water storage tank
(2), said valve (4) comprising a valve housing (21) with a cylindrical cavity (22)
and a rotating cylinder (25) housed therein and provided with a transverse through
conduit (26) which, when the valve is in the open position, connects inlet (23) and
outlet (24) conduits of the valve, the ends of the transverse conduit being adapted
so that the rotating cylinder (25) completes the closing of the inlet conduit (23)
and of the outlet conduit (24) non-simultaneously. The border of the ends of said
transverse conduit (26) and of the inlet (23) and outlet (24) conduits are provided
with a cutting edge, so as to produce a scissor effect. The system also comprises floating watertight joints (29) arranged within recesses in the adjacent surfaces of each pair of elements that undergo relative movement, said joints (29) being pressed against said surfaces by means of a pneumatic system when the moving elements (25) are at rest. |
[0001] The present invention relates to a vacuum toilet system for moving installations and civil constructions which can be used, for example, in railways, and is of the type which comprise toilet bowls, a waste water storage tank, a valve connecting each bowl with this storage tank and a device controlling the operation of the system. In these vacuum toilet systems the waste water storage tank is kept at a pressure which is lower than atmospheric pressure in order to induce the passage of water from the bowl to the storage tank when the connecting valve is opened.
BACKGROUND OF THE INVENTION
[0002] European Patent Application EP-A-277 786 describes a vacuum toilet system particularly for aeroplanes which comprises toilet bowls, a waste water storage tank, a valve which connects each bowl to said storage tank, an air extraction conduit with means of causing a negative pressure in the storage tank and control means for the operation of the assembly. This and other known systems have a number of drawbacks.
[0003] The watertightness between the moving and fixed parts of the assembly is insufficient since the traditional watertight joints with which these known systems are provided are subject to wear, deteriorate rapidly due to friction with the moving parts and do not guarantee a long-lasting and reliable hermetic seal.
[0004] Another limitation of the known systems is due to the lack of protection of the storage tank pressure reducing means which can suffer from damage caused by solid bodies in suspension in the waste water.
[0005] Furthermore, the known systems do not allow the low pressure in the waste water storage tank to be maintained between two actuation cycles of the storage tank pressure reducing means.
DESCRIPTION OF THE INVENTION
[0006] The present invention has been developed with the aim of overcoming the aforementioned limitations. It consists of a vacuum toilet system of the type already described in which the valve comprises a valve housing with a through conduit, a rotating element to open and close the passage of fluid through the valve, and actuating means for rotating said rotating element, and is characterised in that said valve housing comprises a cylindrical cavity and inlet and outlet conduits which are transverse thereto, and said rotating element consists of a cylinder which is housed in said cavity and is provided with a transverse through conduit, which, when the valve is in the open position, connects the inlet and outlet conduits of the valve housing, the ends of the transverse conduit being adapted so that the rotating element completes the closing of the inlet conduit and of the outlet conduit of the valve housing non-simultaneously.
[0007] In this way the inlet and outlet conduits are closed at different moments and, in the event that there is some object interposed in the valve during closure, the force needed to achieve complete closure is reduced by half.
[0008] Advantageously, at least part of the border of the ends of the transverse conduit of the rotating element is provided with a cutting edge, and, according to one preferred embodiment, a metal sleeve is inserted into the cylindrical cavity of the valve housing and is provided with orifices which correspond to the inlet and outlet conduits, at least part of the border of said orifices being provided with a cutting edge such that together with the cutting edge of the border of the ends of the conduit of the rotating element a scissor effect is produced.
[0009] These characteristics allow to guarantee the closure even when there are solid bodies interposed in the valve.
[0010] Advantageously the toilet system is provided with watertightness means which consist of floating watertight joints provided in suitable housings between the adjacent surfaces of each pair of elements that undergo relative movement, said floating joints being forced against said surfaces by means of a pneumatic system when the moving elements are at rest.
[0011] This watertightness system provides a reliable and long-lasting seal, since it allows greater pressure to be exerted on the joints when the moving elements are at rest, thereby ensuring good watertightness, and lower pressure when said elements are moving, avoiding premature wear of the joints.
[0012] In the example of the rotating element of the valve described, floating watertight joints are provided within annular recesses formed in each base of the cylindrical cavity of the valve housing, said recesses and joints being shaped so that they define between them annular channels which lead to a controlled compressed air source in order to press the joints against the respective bases of the rotating element.
[0013] O-rings are interposed between the watertight joints and the walls of their recesses in order to ensure that the waste waters and the air of the pneumatic system are kept separated at all times.
[0014] According to one advantageous embodiment of the invention, the system further comprises a non-return device to maintain the vacuum in the waste water storage tank, said non-return device being arranged in the conduit for extracting air from the storage tank. This device may be a diaphragm valve which actuates against air-passage orifices and allows the partial vacuum created in the storage tank to be maintained for the required amount of time.
[0015] Thus the amount of air used by the system is reduced and as result its efficiency is improved.
[0016] In order to protect the elements of the air extraction conduit from solid bodies in suspension in the waste waters of the storage tank, the system is further provided with a mechanical filter arranged in the air extraction conduit at the outlet of the waste water storage tank.
[0018] The system which forms the object of the present invention is provided with means of operational control comprising independent alarms for each bowl, general alarms for the common parts of the system and an alarm in case of a break in the control circuit, and further comprising switches to independently activate each operational phase of the system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order that the invention be better understood, the accompanying drawings show by way of a non-limiting example one practical embodiment of the present invention.
[0020] In said drawings:
figure 1 is a schematic representation of the vacuum toilet system assembly according to the present invention;
figure 2 is a plan view, in section, of the valve of the system shown in figure 1;
figure 3 is an elevation view, in section, of the same valve as figure 2 showing a practical application of the watertightness means;
figure 4 shows the watertightness means of figure 3 in more detail;
figure 5 and figure 6 are side elevation views of the ejector, and of the diaphragm valve and mechanical filter assembly, respectively, of the system shown in figure 1; and
figure 7 is a sectional view of the diaphragm valve of figure 6.
DESCRIPTION OF A PREFERRED EMBODIMENT
[0021] Figure 1 is a schematic representation of a vacuum toilet system assembly which is composed of one or more toilet bowls 1 and a waste water storage tank 2, connected by means of an evacuation conduit 3 in which a valve 4 is provided for opening and closing said conduit.
[0022] The system also comprises an ejector device 5 to create a partial vacuum in the storage tank 2 and in the evacuation conduit 3 through the air extraction conduit 6; an odour filter 7 is placed in the conduit 6.
[0023] Another element of the system is the water pump 8 for cleaning the bowls 1 of residues. The pump sucks from a storage tank (not shown) through a manually operated shutoff cock 8a. The pump feeds a plurality of sprinklers 19 which are provided on the walls of the bowl 1.
[0024] The waste water storage tank 2 comprises an outlet 9 for emptying the tank, heating resistances 10 to prevent the water from freezing and a level detector 11.
[0025] The different elements of the system are actuated or activated from a control panel 12 either directly or by means of pneumatic electrovalves 13, 14, 15 fed by a compressed air source (not shown) through pressure regulators 16.
[0026] The control panel 12 receives signals from a manual switch 17 which activates the operational cycle, from an indicator 18 of the water level in the bowl 1 and from the level detector 11 of the storage tank 2.
[0028] It consists of a valve housing 21 which comprises a cylindrical cavity 22 and an inlet conduit 23 and an outlet conduit 24 oriented transversally to said cavity, and a rotating cylinder 25 housed within said cavity and provided with a transverse through conduit 26. When the valve is in the open position this conduit 26 connects the inlet conduit 23 and outlet conduit 24 together, thus connecting the bowl 1 and the waste water storage tank 2.
[0029] The cylinder 25 is rotationally driven by the motor 20, controlled from the control panel 12.
[0030] A metal sleeve 27 is provided within the cavity 22 of the valve housing 21, which may be of a plastic material, and has orifices which correspond to the inlet conduit 23 and the outlet conduit 24.
[0031] The edges of the conduit 26 are machined in such a way that when the cylinder 25 is rotated so as to close the valve, the inlet conduit 23 and the outlet conduit 24 do not close simultaneously but rather one after the other.
[0032] In order that the valve can close when there are solid elements in suspension, both the edges of the conduit 26 across the cylinder as well as the edges of the orifices of the sleeve 27 are machined so as to have cutting edges 25c and 27c which together produce a scissor effect at the moment of closure.
[0033] The system of the invention is provided with means to ensure optimum watertightness between the elements which undergo relative movement. An example of these watertightness means is shown in figure 3 and in more detail in figure 4, which represent one embodiment of said watertightness means applied between the valve housing 21 and the rotating cylinder 25.
[0034] As the sectional view of figure 4 shows, in each base of the cylindrical cavity 22 of the valve housing 21 is formed a circular groove 28 in which a watertight joint 29 fits with a certain amount of clearance ("floating"). The watertight joint 29 may be of any suitable material, for example a synthetic material such as the one known commercially by the name TEFLON.
[0035] The groove 28 and the joint 29 are shaped in such a way that between them they define an annular channel 30; this channel 30 is connected to air inlets 31 which are connected in turn to the compressed air source (not shown) through the line 33 of figure 1.
[0036] When the rotating cylinder 25 is at rest, the electrovalve 14 allows the passage of compressed air along line 33 so that in the region 25a the joint 29 is pressed against the base of the cylinder 25, thereby ensuring perfect watertightness.
[0037] As the cylinder 25 begins to rotate, the electrovalve 14 closes off the supply of air to the channel 30 and the joint 29 is subjected only to a residual pressure, so that the frictional wear due to contact with the base of the cylinder at 25a is relatively small.
[0038] In order to prevent the water from penetrating inside the groove 28 and reaching the air channel 30, contaminating the pneumatic system, O-ring seals 34 are provided between the joint 29 and the walls of the groove 28.
[0039] These watertightness means, with a floating joint which is selectively pressed against a moving element by means of compressed air, can be similarly applied to other parts of the system.
[0040] The ejector 5, shown in figure 5, is known in the state of the art and is not represented in detail. Its operation is based on forcing air to pass (arrow A) through a nozzle and using the negative pressure created therein to extract air (arrow B) from the waste water storage tank 2 by the Venturi effect and thus creating a partial vacuum. The air supplied and the air extracted from the storage tank are expelled to the atmosphere (arrow C).
[0041] Figure 6 represents the non-return device 40 and filter device 43 assembly. To maintain a partial vacuum inside the storage tank 2 the non-return device 40 is provided in the air extraction conduit 6. This device can be a diaphragm valve, such as the one which is represented in figure 7, with a plurality of axial orifices 41 and a flexible diaphragm 42 which allows the passage of fluid through the orifices 41 in one direction only (arrow D).
[0042] The conduit 6 for extracting air from the storage tank 2 is also provided with a mechanical filter 43 to reduce the danger of damage to the ejector 5, the non-return device 40 and the odour filter 7 caused by solid bodies in suspension in the waste water. This filter 43 comprises a sieve 44 and a vacuum indicator 45.
[0043] The system control means comprise a modular logic controller, with boards that can easily be replaced in the event of failure, and which can be used for a plurality of toilet bowls. Said control means are provided with independent alarms for each bowl which indicate the unit and the point where a problem has occurred, general alarms for the common parts of the system, and a control system break alarm so that an alarm signal can be transmitted even in the case of failure of the control means.
1. A vacuum toilet system for moving installations and civil constructions which comprises
at least one toilet bowl (1), a waste water storage tank (2), a valve (4) which connects
each bowl with said storage tank, an air extraction conduit (6) with means (5) of
causing a negative pressure in the storage tank (2), and control means for the operation
of the system, said valve (4) comprising a valve housing (21) with a through conduit,
a rotating element (25) for opening and closing the passage of fluid through the valve
(4), and drive means (20) for said rotating element (25), characterized in that said valve housing (21) comprises a cylindrical cavity (22), an inlet conduit
(23) and an outlet conduit (24) transverse thereto, said rotating element (25) including
a cylinder housed within said cavity (22) and provided with a transverse through conduit
(26), which, when the valve is in the open position, connects the inlet conduit (23)
and the outlet conduit (24) of the valve housing (21), the ends of the transverse
conduit (26) being adapted so that the rotating element (25) completes the closing
of the inlet conduit (23) and of the outlet conduit (24) of the valve housing (21)
non-simultaneously.
2. A system according to Claim 1, characterized in that at least part of the border of
the ends of the transverse conduit (26) of the rotating element (25) is provided with
a cutting edge (25c).
3. A system according to Claims 1 or 2, characterized in that a metal sleeve (27) is
inserted in the cylindrical cavity (22) of the valve housing (21) and is provided
with orifices corresponding to the inlet conduit (23) and outlet conduit (24), at
least part of the border of said orifices being provided with a cutting edge (27c)
such that together with the cutting edge (25c) of the edge of the ends of the conduit
of the rotating element (25) a scissor effect is produced.
4. A vacuum toilet system for moving installations and civil constructions which comprises
at least one toilet bowl (1), a waste water storage tank (2), a valve (4) which connects
each bowl with said storage tank, means (5) of causing a negative pressure in the
storage tank (2), and and control means for the operation of the system, characterized in that it comprises watertightness means consisting of watertight joints (29) which
are arranged floating within suitable recesses (28) between the adjacent surfaces
of each pair of elements (21,25) that undergo relative movement, said floating joints
(29) being pressed against said surfaces (25a) by means of a pneumatic system when
the moving elements (25) are at rest.
5. A system according to Claims 1 and 4, characterized in that floating watertight joints
(29) are arranged within annular recesses (28) formed in each base of the cylindrical
cavity (22) of the valve housing (21), said recesses (28) and said joints (29) being
shaped so that they define between them annular channels (30) which lead to a controlled
compressed air source so as to press the joints (29) against the respective bases
(25a) of the rotating element when it is at rest.
6. A system according to Claim 5, characterized in that O-ring seals (34) are arranged
between the watertight joints (29) and the walls of their recesses (28) in order to
ensure watertightness between the waste waters and the pneumatic system.
7. A system according to Claim 1, characterized in that it further comprises a non-return
device (40) to maintain the negative pressure in the waste water storage tank (2),
said non-return device (40) being arranged in the conduit (6) for extracting air from
the storage tank (2).
8. A system according to Claim 7 characterized in that said non-return device (40) is
a valve with a diaphragm (42) actuating against air-passage orifices (41).
9. A system according to Claim 1 characterized in that it further comprises a mechanical
filter (43) arranged in the conduit (6) for extracting air from the storage tank (2)
and at the outlet of said tank (2), in order to prevent solid bodies in suspension
in the waste waters from damaging elements of said conduit (6).
10. A system according to Claim 1 characterised in that each toilet bowl (1) comprises
a plurality of water sprinklers (19) for cleaning.
11. A system according to Claim 1, comprising operation control means, characterized in
that said control means comprise independent alarms for each toilet unit, general
alarms for the common parts of the system, and an alarm for the event of a break in
the control circuit, and in that it is further provided with switches for independently
activating each of the operational phases of the system.