Electrically and hydraulically actuated flow-distributing valve unit

A flow-distributing valve unit which is actuated electrically and hydraulically is disclosed, the improvement consisting in a double-acting piston distributor reciprocable in a chamber to which fluid intake and fluid discharge conduits are connected, the fluid intake ducts having fixed throttling passageways whereas variable width passageways are provided for the fluid discharge ducts. The widths of the discharge passageways for the fluid are varied by electromagnetic controls. A flow-distributing valve is integral with the double-acting piston mechanism and is connected with a valve actuator which can either be manual or moved by a servomechanism.

This invention relates to an electrically and hydraulically actuated 
flow-distributing valve unit which is proportionally regulated. 
The electrically and hydraulically actuated valve units known heretofore 
are essentially composed by the valve proper and by an electrical and 
hydraulic actuator for such valve. The valve is essentially composed by a 
body in the interior of which a seating is formed for allowing a slider to 
glide therein: fluid flow passageways are opened through such a seating. 
The slider has an appropriate outline so as to make possible both mutually 
to connect the intake ducts and the fluid exploiting ducts as well as to 
cut off the incoming fluid thus preventing same to flow towards the 
exploitation ducts, as a function of the position of the slider in its own 
seating. The slider is driven by the electric and hydraulic actuator 
aforementioned. More exactly, the actuator is composed, in the linear 
motion type, by a piston which can slide in the interior of a cylindrical 
seating having its two end headers bored to allow the passage of the 
piston stems therethrough, either stem being connected to the valve slider 
in order to actuate the latter. The piston partitions the cylindrical 
seating into two chambers which are separated from each other and which 
can alternately be connected to a source of fluid under pressure, or to 
exhaust. The pressure differential between the two chambers, which 
originates the linear shift of the piston, is achieved by means of a 
separate electrical and hydraulic distribution member, which is, however, 
hydraulically connected to the chambers and is a further component part of 
the system. Such distribution member is driven by an 
electric-signal-generating component, which, in the most sophisticated 
embodiments, is fed back by a transducer for controlling the position or 
other parameters of the movement of the slider-actuating stem. 
Valve units of the kind referred to above as disclosed by the conventional 
art are impaired by defects. In the first place, these units are composed 
by a fair number of component parts. This fact requires a considerable 
space for installing the unit and the assemblage is uneasy. Such component 
part requires a casing to shield it from the external agents. The 
connection between the several component parts imposes the use of 
mechanical, electrical and hydraulic connection lines which involve sizing 
and location problems which are not readily solved when designing such an 
installation. These units, moreover, are often characterized by long 
response times: these are due also to the lengths of the 
component-interconnection ducts, which limit the possibility of 
adjustment. 
The principal object of the present invention is to overcome the defects 
indicated above which are present in the conventional art. 
Such object is achieved by virtue of an electrically and hydraulically 
actuated flow-distributing valve units, which is characterized in that it 
comprises: 
An electrical-hydraulic actuator comprised of a body in the interior of 
which a cylindrical seating is formed which is adapted to receive a tight 
sealing sliding piston which partitions the seating into two hydraulically 
separated chambers individually connected to intake and outlet ducts for a 
pressurized fluid, said intake ducts having fixed throttled passageways, 
said outlet ducts exhibiting throttled passageways of variable width, the 
degree of throttling being adjustable by virtue of electrically and 
magnetically actuated valve cores which restrict the flow and originate 
controlled pressure drops, said piston being extended at both ends into 
two stems, and 
a flow-distributing valve integrally connected to said actuator, said valve 
having a slider gliding therein and connected to either stem of said 
actuator. 
Furthermore, to allow a regulation of the flow which is accurately 
proportional to the position of the valve slider and to prevent the slider 
(which has an appropriate outline and generates during its adjusting 
movements throttlings of variable width for the fluid flow passage area) 
from originating pressure drops between the intake duct and the fluid 
utilization duct, which are variable as a function of the width of the 
throttling so provided, the valve is preferably embodied by a body in the 
interior of which there is formed a cylindrical seat for having said 
slider gliding, said seat having formed therethrough flow passageways for 
a pressurized fluid which are connected to flow conduits for such fluid, 
in the interior of such slider there being formed at least an axial 
channel-shaped hollow space which communicates with: 
at least a bore, radially passing through the slider wall and which, in 
alternate sequence consistently with the position of the slider, is either 
opened towards the port connected to utilization ducts, or is opened 
towards the port connected to the fluid discharge ducts, or remains in the 
shuttered position against the wall of said seat, 
a set of bores, spaced apart from said first named bore and passing 
radially through the slider wall and which are longitudinally arranged 
serially, and which, in alternate sequence consistently with the position 
of the slider, are either opened towards the port connected to the intake 
ducts, or towards the port connected to the fluid utilization ducts, or 
which remain in the position in which they are shuttered by the wall of 
said seat, 
at least a bore, spaced apart from the previously named ones, passing 
radially through the slider wall and which, in alternate sequence 
consistently with the slider position is either opened towards the 
connection port towards a pressural compensator, or remains in the 
position in which it is shuttered by the wall of said seat, 
nonreturn valve means being provided in said cavity for cutting off the 
fluid which comes from the intake duct towards the other conduits, 
latching means being provided at the slider ends for latching the 
actuators for said valve.

By way of nonlimiting example, a flow-distributing valve unit is 
essentially composed by a flow-distributing valve 60 and an electrical and 
hydraulic actuator 10 for said valve 60 and integrally connected 
therewith. The actuator 10 is structurally composed by a compact body 20 
in the interior of which a substantially cylindrical seat, 30, is formed, 
within which a piston 40 slides in a seal-tight manner. The piston 40 
partitions the seat 30 into two chambers, 31 and 32, which communicate 
with intake ducts 33 and outlet ducts 34, respectively. The conduits 33 
are connected to a fluid delivery duct 35 under pressure and the ducts 34 
are connected to a duct 36 for discharging same fluid. Two fixed 
throttling passageways 50 are inserted between the duct 35 and the ducts 
33. Between the ducts 34 and the duct 36 two variable-width throttling 
passages unnumbered, are inserted. Each variable-width throttling passage 
is originated by virtues of the translational shift of a core 51 which 
cuts off and throttles the fluid flow coming through the duct 34. The core 
51 is urged towards a complementary core 52 by a magnetic force generated 
by a coil 53. Such magnetic force, as it is apparent, is proportional to 
the intensity of the current flowing through the coil 53. The piston 40 is 
concentrical with a cylindrical stem 41, one end, 42, of which is adapted 
to match a slider 63 of the valve 60: the other end 43 of 41 is connected 
by a rack-and-pinion assembly to a position-transducer 44. The transducer 
44 feeds back a control station 45 which is electrically connected with 
the outside through a connector 46 and adapted to supply electric signals 
to the coilings 53. By so doing, an electric pulse applied to the coilings 
53 and coming from the control station 45, the latter being influenced by 
the transducer 44 and by electric signals from outside, generates magnetic 
forces which move the cores 51. An appropriate proportioning of said 
forces causes pressure drops in the ducts which are such as to originate a 
pressure differential between the two chambers 31 and 32 so as to shift 
the piston 40 in its seating. The magnitude of such pressure differential 
influences the parameters of movement of the control stem 41 of the slider 
63. 
The flow-distributing valve 60 is composed by a compact body 61 in the 
interior of which there is formed a cylindrical seat 62 for the slider 63 
therein. Through the seat 62 there are opened ports 64, 65, 66, 84, 85 for 
allowing a fluid to flow therethrough. The ports 64 and 84 are in 
communication, respectively, with fluid utilization conduits 74 and 94. 
The ports 65 and 85 communicate, respectively, with intake ducts 75 and 95 
and these, in their turn, are connected to an inlet channel 76 for the 
fluid coming from a source of pressurized fluid (not shown). 
The port 66 communicates with a pressure compensator of conventional make 
and not shown. The ends of the seat 62 are extended into closed chambers 
67 and 87 which communicate with fluid discharge ducts not shown. In the 
interior of said slider 63 there are formed hollow spaces 68 and 88 in the 
form of axially running channels which communicate with bores 69, 70, 71, 
89, 90 and 91 as best seen in FIG. 2. The area of the bores 69, 89 is 
generally double the sum of the area of the bores 70, 90, respectively. 
Said slider 63 offers seats for the valves 72 and 92 of the nonreturn type 
which cut off the fluid which comes, respectively, from the hollow space 
68 to the bores 69, and from the hollow space 88 to the bores 89. The 
slider 63 also offers a seat to the nonreturn valves 73 and 93 which cut 
off the fluid coming, respectively, from the hollow space 68 to the bore 
71 and from the hollow space 88 to the bore 91 to transfer the value of 
the pressure existing in the hollow spaces 68 and 88 to the pressure 
compensator. 
In operation, an electric command to the coils 53, originated by the 
control station 45, the latter being influenced by the transducer 44 which 
indicates the position of the stem 41 and thus also that of the slider 63 
and being also influenced by electric commands sent from the outside by an 
operator, generates, as aforesaid, magnetic forces driving the cores 51. 
If the magnitudes of these forces are properly adjusted so that the 
pressure of the fluid in the chamber 31 exceeds the pressure of the fluid 
in the chamber 32, the piston 40 and thus also the slider 63 are shifted 
towards the right with respect to the position as viewed in FIG. 1. 
By so doing, the fluid under pressure coming from the conduit 75 flows 
through the port 65, the bores 70, the hollow space 68, the valve 72 as 
actuated by the hydraulic thrust of the fluid itself, and the bores 69, 
reaches at last the fluid utilization conduit 74. It is possible to 
achieve an accurate regulation of the fluid flowing towards the conduit 
74, especially by virtue of the sequential presence of the bores 70, the 
opening of which towards the port 65 can be throttled by the position of 
the slider 63. A fraction of the fluid which flows into the hollow space 
68 passes through the valve 73 (energized by the hydraulic fluid pressure) 
and through the port 66 to energize the pressure compensator: this in 
order to maintain a constant pressure drop which is limited for the valve 
60 irrespective of the slider position and thus of the throttlings which 
are originated in the valve as a function of the instantaneous positions 
of the slider. 
In very much the same way as outlined above, the slider 63 can be shifted 
towards the left so that the intake conduit 95 is placed in relationship 
of communication with the utilization conduit 94. 
When the slider 63 is in the latter position, the fluid existing in the 
duct 74 flows out through the port 64, the bores 70, the hollow space 68, 
the valve 72, the bores 69 and reaches the chamber 67, to be discharged 
externally of the valve 60. The same is true of the fluid existing in the 
duct 94 which reaches the chamber 87 and is discharged externally of the 
valve 60 when the slider 63 is shifted towards the right. It is apparent 
that, when the slider 63 is in the inoperative position as in FIG. 1, the 
intake ducts 75 and 95 and the utilization ducts 74 and 94 are shuttered 
by the walls of the slider 63. The slider 63 has at either end a means, 
96, for latching the corresponding end 42 of the stem 41 and, at the 
opposite end, a means 98 for latching the connecting rod of a manual 
actuator (not shown) of conventional make, which might be used, for 
example, in the case of malfunction of the electrical and hydraulic 
actuator. The manual actuator can easily be installed in lieu of the 
closing lid 99. The valve unit has gaskets 97 for providing a tight seal 
whereover required. 
Obviously, modifications and changes can be introduced in the exemplary 
embodiment which has been described hereinabove, without departing from 
the scope of the present invention. 
In the exemplary embodiment described in the foregoing, there are provided 
in the slider two hollow spaces 68 and 88 in the form of channels with the 
respective openings, but the possibility cannot be excluded of having a 
slider with more than two channel-shaped spaces with relative bores, the 
operation being akin to what has been disclosed hereinabove. It is 
possible simply to provide a slider with a single internal hollow space 
and relative bores: if so, the valve fulfils a mere regulation task. 
The transducer is not compulsorily of the kind shown herein, but a 
transducer can be provided for any static or dynamic parameters of the 
stem 41, to which such a transducer can be variously connected by a 
linkage. Finally, it is possible, still without departing from the scope 
of the invention, to provide an electrical and hydraulic actuator which is 
less sophisticated than that disclosed for the above described exemplary 
embodiment, by dispensing with the transducer and the control station and 
by directly connecting the coilings 53 of the electromagnetic system with 
an electric signal generator external to the electrical and hydraulic 
actuating unit.