Control mechanism for two cut-off devices mounted in series

A mechanism for controlling two rotatable cut-off devices which are mounted in series in a shell for connection to one and the same pipe, comprises a jack in respect of each cut-off device, each jack being articulated to a lever fast with a journal of a respective one of the cut-off devices and to the shell in the zone thereof supporting the journals of the other cut-off device. The invention is particularly applicable to the valves for protecting a hydraulic machine in a high-fall hydraulic power station.

The present invention relates to a control mechanism for two cut-off 
devices mounted in series for connection to one and the same pipe, which 
mechanism is particularly but not exclusively intended for the spherical 
valves of a high-fall hydraulic power installation. 
In installations of this type, comprising turbines having fixed 
guide-rings, or turbine pumps, two valves are arranged in series, as a 
safety measure, in order to protect the hydraulic machinery. The upstream 
valve constitutes the safety device for emergency shut-off if there is an 
accident involving the downstream valve or the downstream pipe; shut-off 
in the latter case is referred to as "open sluice" shut-off. The 
downstream valve ensures the normal opening and closing operations. 
Hitherto, the cut-off devices of these valves have been controlled in a 
conventional manner, as for single valves, that is to say by means of 
hydraulic jacks anchored to the ground in concrete or fixed to the shell 
of the valve. 
The conventional control, shown in this figure for a single valve, 
comprises one (or two) jacks acting on one (or both) of the ends of the 
journals of the cut-off device. The or each jack 4 applies a torque to the 
journal via a lever 1 keyed on the journal 2. The end fork-joint of the 
rod of the piston oscillates about an axle 3 fixed to the lever 1. The 
cylinder of the jack 4 oscillates about the axle 5 of a fork-joint 
anchored in concrete. 
In installations with two such valves in series, there are two identical 
sets of such control equipment. The forces involved in operating a cut-off 
device can exceed a hundred tonnes. The concrete beds must therefore be 
capable of withstanding additional tensile and compressive stresses, and 
this necessitates expensive civil engineering work. 
Alternatively, jacks fixed directly to the shell of the valve can be 
employed. French Pat. No. 1,363,146 illustrates a control of this type in 
the case of a single valve. In this arrangement, the flanges for fixing 
the jacks adjoin the shell and greatly complicate the geometrical shapes. 
Concentrations of stress appear at right-angles to the reinforcements and 
require an increase in dimensions, thus involving a greater cost than in 
the case of a shell of which the shape remains approximately spherical. 
It is an aspect of the present invention to provide a new solution whereby 
the shell retains a simple shape and the need to apply the operating 
forces to the foundations is avoided. 
According to the invention there is provided a mechanism for independently 
controlling two cut-off devices arranged in series for connnection to one 
and the same pipe, each cut-off device being mounted for rotation in 
journals carried by fixed shell means and being rotatable by an operating 
lever externally of the shell means and fast with a respective journal, 
said mechanism comprising a jack in respect of each cut-off device, each 
jack being articulated to said operating lever of a respective one of said 
cut-off devices and to said shell means in the zone thereof supporting 
said journals of said other one of said cut-off devices. 
According to a particular embodiment of the invention each of said cut-off 
devices is provided with only one operating lever fast with a respective 
one of said journals thereof, each of said levers being located 
respectively on a different side of said shell means, each jack for 
operating a said cut-off device being articulated on said shell means 
around the end of the other one of said journals of said other respective 
cut-off device which is not provided with said lever.

FIGS. 2 and 3 show a unit in which two spherical valves 10 and 20 are 
mounted in series on a pipe which is simply shown in dot-and-dash lines at 
both ends of the unit. The two valves are separated by a disconnecting 
sleeve 7. The valve 10 comprises, in known manner, an internal cut-off 
device 11 carried by two journals 12 and 13 which rotate freely in 
leaktight bearings formed in bosses on the shell 10. The journals 12 and 
13 project outside the shell 10. In a completely analogous manner, the 
valve 20 comprises a cut-off device 21, not shown in the figures, which 
rotates on journals 22 and 23 projecting outside the shell 20. The 
90.degree. rotation between the open or closed positions of the cut-off 
device 11 is controlled by means of a lever 15 keyed on the journal 13. 
The end of the lever 15 is articulated at 16 on the head of the rod 17 of 
an operating jack 18. The body of the jack 18 is articulated on the 
journal 22 of the cut-off device 21. In a symmetrical manner, the rod 27 
of a jack 28, the body of which jack is articulated on the journal 12 of 
the cut-off device 11, is articulated at 26 on the lever 25 of the cut-off 
device 21. In FIG. 3, the jack 18 is shown in the totally extended 
position, which corresponds to the fully open position of the cut-off 
device 11; on the other hand, the jack 28 is shown in the completely 
retracted position, which corresponds to the fully closed position of the 
cut-off device 21. 
Preferably the articulations of the jacks on the levers and on the journals 
are cylindrical articulations. 
In the arrangement which has now been described, it will be noted that the 
operating forces only constitute internal forces. The foundations do not 
bear any of these forces. Moreover, the operating forces passing through 
the shell do not require any special reinforcement because they remain 
small in comparison with the reaction of support of the cut-off device. 
The shell is thus approximately axisymmetrical and comprises 
axisymmetrical reinforcements, which makes it possible to optimise the 
size and make better use of material. 
A significant reduction in bulk, compared with the conventional arrangement 
referred to in FIG. 1, and also compared with the arrangement with a 
servomotor incorporated in the shell of each valve, as described in French 
Pat. No. 1,363,146, will also be noted. 
The modified embodiment shown in FIGS. 4 and 5 makes it possible to retain 
the symmetry of the operating forces of each cut-off device, two jacks 
acting in parallel on each of its two journals. In these figures, each of 
the journals 12 and 13 of the cut-off device 11 carries an identical lever 
15 which is articulated on the rod 17 of a respective one of two jacks 18, 
which are supplied in parallel. The body of each jack 18 is articulated on 
a false journal 39, the axis of which is parallel to the journals 12 and 
13, and which is integral with the shell 30 of the second valve in the 
zone of the journals of the other cut-off device. In these figures, the 
two jacks 18 are shown in the completely extended position, which 
corresponds to the fully open position of the cut-off device 11. 
In the shell 30, the cut-off devie 31, not shown in the figures, rotates on 
journals 32 and 33, the axis of which is perpendicular to that of the 
journals 12 and 13 of the cut-off device 11. A lever 35 is keyed on each 
of the journals 32 and 33 and each is articulated on the rod of a 
respctive jack 38. The body of each jack 38 is articulated on a respective 
false journal 19, the axis of which is parallel to the journals 32 and 33, 
and which is integral with the shell 10 in the zone of the journals 12, 
13. The two jacks 38 are shown in the completely retracted position, which 
corresponds to the fully closed position of the cut-off device 31. 
Preferably the axes of the journals 19, 39 are contained in the transverse 
planes containing the axes of the journals 12, 13 and 32, 33 respectively. 
Of course, the invention is not intended to be strictly limited to the 
embodiments which have been described by way of example; on the contrary, 
it also includes embodiments which only differ therefrom in details, in 
different methods of operation or in the use of equivalent means. 
Thus, the control mechanisms which have been described above for two 
separate valves, apply in an absolutely analogous manner to the case of a 
double valve with two cut-off devices in the same shell, for example as 
shown in FIG. 6 for the case where the axes of the cut-off devices are 
parallel. As shown in FIG. 6 a jack 48 for controlling spherical cut-off 
device 41 is articulated on the free journal 52 of cut-off device 51. The 
rod 47 of the jack 48 is articulated at 46 on lever 45 for controlling 
journal 43 of the cut-off device 41. A symmetrical arrangement, on the 
other side of the unit, is provided for operation of the other cut-off 
device 51.