Ball valve provided with a lock ring

A ball valve having a valve body within which is provided a ball for opening and closing the valve. The ball valve is constructed with bushings and lock rings arranged for ease of assembly and disassembly for inspection of the wear of internal ring seals. An internal lock ring is provided with recesses in an end face for receiving a tool which is part of the operating handle of the valve.

BACKGROUND OF THE INVENTION 
Ball valves are known which consist of a substantially cylindrical valve 
body and a rotatable ball-shaped valve element which is drilled and 
actuated to the closed and opened positions by an operating handle through 
an operating shaft. In ball valves of known type the valve body is 
provided, on one side, with a sort of inwardly extending flange, acting as 
a seat for an annular gasket which bears against the ball-shaped valve 
element on the other side. On the opposite side, a second annular gasket 
for the rotatable ball is supported by a rest bushing inserted inside the 
valve body. The flanged ends of the pipes converging on the valve are 
tightened to both ends of the valve body by means of lock rings which are 
screwed to the external surface of the valve body. 
This kind of arrangement allows to remove the valve in order to verify the 
state of wear of the gaskets, without removing either valve duct. 
However, in some cases, it may be necessary to disassemble the pipe 
connected to one of the two sides of the valve, the valve being closed, 
while in the other pipe a fluid is still under pressure. Because of this 
necessity, it is compulsory to place the valve in such a way that the 
gasket rest bushing is always set upstream of the pressure side; 
otherwise, the bushing, the related gasket and the valve ball itself, 
could be shot out of the valve body by the pressure on the other side of 
the valve. 
Such type of known valve has two defects: first of all, when assembling it, 
the flow direction of the fluid should be known: but even so an assembling 
mistake is always possible; secondly the pipe may be inserted into a 
complex circuit where, depending on the system regulating conditions, the 
pressure can be indifferently applied on either side of the valve. 
OBJECT OF THE INVENTION 
The purpose of the present invention is to obviate such disadvantages by 
providing a lock ring screwed inside the valve body, thus forming a lock 
for the gasket rest bushing. 
The valve can thus be assembled indifferently in either direction, and 
still it is always possible to disassemble one of the two parts of the 
gasket when the other is under pressure.

DESCRIPTION OF A PREFERRED EMBODIMENT 
With particular reference to the above figures: 10 indicates the valve body 
or valve "box"; it has a substantially cylindrical external shape 11 and 
is provided with a threaded part 12, 13 at its two ends, for two lock 
rings 20, 20'. 
The lock rings 20 and 20' are provided with a tubular section 21, 21' 
having an inner thread 22, 22' to engage thread 12 and 13; at one end they 
are provided with a flange 23, 23' which is turned inwards of the ring in 
order to engage external flanges 31, 31' of pipes 30, 30'. 
It should be noted that, in a known way, lock rings 20, 20' are provided 
externally with projections 24, 24' and grooves 25, 25', so that the lock 
ring may be grasped by means of a suitable tool. 
Again in a known way, each pipe 30, 30' can form a single piece with 
external flange 31, 31'; in a known way, in most cases pipes 30, 30' 
consist of a tube 32, 32' engaged inside an end bushing 33, 33' provided 
with the above said external flange 31, 31'. Tube 32, 32' may be joined to 
the end bushing 33, 33' in various ways: by screwing, glueing or 
mechanical shrinking. 
Internally, valve body 10 is provided, at one end, to the left of the 
figures, with a bore 14 extending to the central part of the valve body. 
At the other end, to the right of the figures, the bore is partially 
closed by an annular flange extending 15 inwardly towards the axis of the 
valve body and acting as stop for the frontal end 34 of pipe 30. The 
frontal end 34 of pipe 30 bears against the frontal end 16 of the valve 
body. 
An annular groove 17, placed against the internal flange 15 and fit to 
receive a sealing O-ring 18, is provided in a known way on the frontal 
surface 16 of the valve body. 
Valve body 10 is provided with a radial passage 19 for the driving shaft 40 
of valve element 41, consisting in a rotatable ball traversed by a 
diametral passage 42 and provided with an impression 43 fit to receive a 
cylindrical tang 44 of non-circular section, projecting downwards from the 
valve stem or shaft 40. 
As shown in FIG. 1, between flange 15 and ball 41 there is an annular 
gasket 45, housed on an annular step 46 of flange 15 of valve body 10. As 
known, in ball valves of this type the second annular gasket 45' of the 
ball-shaped valve element 41, (left of the figures), is pushed against the 
ball 41 by the second lock ring 20' which, instead of pushing during 
operations the frontal end of flange 31' of pipe 30' directly against the 
frontal left end 16' of valve body 10, pushes said flange 31' against the 
base 51 the of rest bushing 50 of gasket 45'. On the axially external 
frontal surface 51 of the rest bushing 50 the of gasket 45' there is 
provided an annular groove 17' housing a lock ring 18'. Therefore, in a 
known way, and with particular reference to FIG. 1, the valve is provided 
with the following elements in succession: pipe 30, flange 15 of valve 
body 10, the sealing gasket 45', ball-shaped valve element 41, rest 
bushing 50 of gasket 45', pipe 30'. 
Besides these known elements, locking nuts 20 and 20' are also typical of 
these ball valves. 
According to the invention, the end of bore 14, opposite to flange 15, is 
provided with a thread 60 fit to receive a lock ring 61, externally 
threaded and provided with two diametrically opposed depressions, not 
shown in the drawing, which allow it to be rotated by means of a suitable 
tool. 
In order to allow ring 61 to be housed on the external surface of rest 
bushing 50, a step 52 is provided which is also suited to receive a radial 
lock ring 54. Lock ring 61 permits to assemble the valve in any position 
in respect of the fluid flow direction, in case that, that the valve is 
closed, the disassembly of one of the two pipes 30 or 30' is required. 
Indeed, if the fluid flow through the valve is in the direction shown by 
harrow F1 in FIG. 1, it is possible, if required, to close the valve by 
rotating the ball 41 thus disassembling the downstream pipe 30' with no 
danger that the rest bushing 50 of gasket 45' may be ejected from the 
valve body; in fact this is provided for by lock ring 61 which is screwed 
on thread 60 of the valve body 10. 
Furthermore, the valve according to the invention, is characterized by two 
further features which make its use most convenient and safe. 
According to the invention, the valve upper tang 47 of drive shaft 40 of 
the ball 41, is provided at its base with a stress raiser 48, as shown in 
detail in FIG. 4. It follows that, if, owing to the ball jamming up, 
handle 70 engaged in upper tang 47 is forced beyond a given limit, the 
breaking of the shaft 40 will occur at the root of the upper tank 47, due 
to the presence of notchings 48 which act as a stress raisers. 
Consequently the breakings of the shaft, at the root of upper tang 47, 
would not compromise the seal of the valve, the breaking section being 
external to the sealing means of the operating shaft 40; the sealing means 
consisting of a groove 49 into which there is inserted an O-ring pressing 
on the inner surface of passage 19 of valve body 10. 
The result is the safe operation of the valve. From the point of view of 
convenience in the use of the valve, handle 70 is provided with a 
longitudinal groove 71 on which two passages 72 are provided. 
In the groove 71, a tool 73 is housed which substantially consists of a 
prismatic bar 74 with a lower face from which two feet or projection 75 
project, fit to be elastically inserted inside the openings 72 of the 
handle 70. 
The distance between the two feet 75 is substantially equal to the mean 
diameter of the lock ring 61 and their thickness is less than the 
thickness of said lock ring. It is therefore possible to provide on the 
frontal surface 62 of lock ring 61 two depressions suited to receive feet 
75; it follows that tool 73 can be used to screw or unscrew lock ring 61. 
Therefore, the valve according to the invention, turns out to be entirely 
provided with a disassembling and assembling means of lock ring 61. 
FIGS. 2 and 3 show a further advantage of the valve according to the 
invention: FIG. 2 refers to the event that the seal gaskets 45 and 45' are 
new so that seal ring 54 is tightened between the valve body 10, rest 
bushing 50 of gasket 45', and the lock ring 61. In such a case, nut 20' is 
screwed onto the valve body body 10 (by the quantity needed) to draw the 
frontal surface of flange 31' near O-ring gasket 18', to guarantee its 
hydraulic seal. 
In this event, therefore, the rotatable ball is engaged longitudinally and 
elastically in view of the fact that the gasket 45' and the rest bushing 
50 do not rest directly and therefore stiffly on lock ring 61 and flange 
31', but through rubber O-ring gasket 54 and 18'. 
When the elastic spring-back of gaskets is no longer sufficient to 
compensate for the wear of the ball 41 and of the gaskets 45-45', it will 
suffice to screw nut 20' which, by pressing flange 31' against the rest 
bushing 50, permits to take up the slack produced and reestablish the 
seal. The device, according to the invention, provides for other 
advantages; in the first place, the fact that it is possible for the rest 
bushing to run inside the lock ring allows to make up for the slacks 
formed because of wear of dilation, by operating quite simply on the 
external nut 20' with no prejudice to the running or interruptions. 
In the second place, the fact that the seat of gasket 54 is delimited by 
three separate bodies (valve body-supporting valve-lock ring) allows for 
easier disassembly and assembly, due to reduction in interferences and 
consequent frictions.