Patent ID: 12204352

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the above cited figures, a blocking device for pipelines for the passage of pressurized gas, of the pilot-operated type, according to the invention is indicated overall by numeral10.

This blocking device10comprises:a blocking valve11, in turn comprising:a connection body12, for the connection between an upstream pipe T1and a downstream pipe T2, inside which there are defined an upstream chamber13, inside which there is an upstream pressure P1, connected to said upstream pipe T1, a downstream chamber14, inside which there is a downstream pressure P2, connected to said downstream pipe T2, and a passage opening15between the upstream13and the downstream14chambers; —a movable shutter16, for obstructing the passage opening15; this movable shutter16is to be understood as consisting of a single body or of a plurality of components which are in any case integral with each other;a stem17carrying the movable shutter16, the movable shutter16being fixed to the stem17;a fluid-dynamic actuator18configured to translate the stem17along the main axis X of the same stem17;thrust means19configured to bring the movable shutter16from an operating position of opening to an operating position of complete closure.

The blocking device10also comprises:a control system20for the controlled actuation of the fluid-dynamic actuator18, which control system20in turn comprises a by-pass group21for equalizing the pressures in the upstream chamber13and in the downstream chamber14, and a pressure reducer group22interconnected with the by-pass group21; the pressure reducer group22is configured to receive a motorization fluid at a supply pressure Pa as input and to supply the fluid-dynamic actuator18with a motorization pressure P3through a motorization line28.

The peculiarity of the blocking device10according to the invention lies in the fact that the control system20comprises a pressure differential selector device23configured to detect a signal of an upstream pressure P1and a signal of the supply pressure Pa of a motorization fluid entering said pressure reducer22, and to alternately determine:the passage of a motorization fluid through said pressure reducer22towards said fluid-dynamic actuator18if the pressure difference P4between said upstream pressure P1and said supply pressure Pa is less than a predetermined balancing pressure difference Peq;the interception of the motorization fluid and the failure to supply said fluid-dynamic actuator18if the pressure difference between said upstream pressure P1and said supply pressure Pa is greater than or equal to the balancing pressure difference Peq.

In the embodiment described here by way of non-limiting example of the invention, the pressure reducer22and the pressure differential selector device23are integrated in a single pressure regulator24, which is well illustrated inFIGS.2and3.

In a variant embodiment of the blocking device according to the invention, schematized inFIG.5and indicated therein with number110, the pressure reducer122and the pressure differential selector device123are constituted by two distinct bodies connected to each other in series; in this variant, the pressure reducer122and the pressure differential selector device123are to be understood to be of a known type.

In the present embodiment, the fluid-dynamic actuator18is of the single-action type, and is configured to move the movable shutter16away from a perimeter edge of the passage opening15.

The thrust means19consist, for example, of a helical thrust spring, configured and positioned to operate with thrust on the stem17or on the movable shutter16, so as to move the latter towards or against the perimeter edge of the passage opening15.

The control and by-pass system20also comprises a switch group25configured to compare a downstream pressure, detected through a downstream signal line29in a downstream pipe T2, with a calibration pressure range Pset, and to operate the closure of the blocking valve11following a higher downstream pressure signal or a lower downstream pressure signal, than the calibration pressure range Pset.

The downstream signal line29is generally connected to a line that is downstream of another pressure regulator or of another valve which in turn is downstream of the blocking valve11.

As a general rule, it is to be understood that the downstream pressure detected by the downstream signal line29may be different from the downstream pressure P2present in the downstream chamber14of the blocking valve11, depending on the configuration of the line located downstream of the movable shutter16of the blocking valve11, wherein this line belongs to the plant in which the blocking device10is inserted.

The switch group25comprises a two-position slide valve26:a first position26aconfigured to operate the opening of a discharge line27for the exit of the motorization fluid from the fluid-dynamic actuator18and the simultaneous closure of the motorization line28, which connects the pressure reducer22with the fluid-dynamic actuator18itself, with consequent closure of the blocking valve11;a second position26bconfigured to operate the closure of the discharge line27and the opening of the motorization line28, with actuation of the fluid-dynamic actuator18, with distancing of the movable shutter16from the passage opening15and consequent opening of the blocking valve11.

The switch group25comprises a pressure switch30, connected through the downstream signal line29to a downstream pipe T2so as to detect a downstream pressure; this pressure switch allows the switching of the slide valve26from the second position26bto the first position26aif it detects a lower or higher downstream pressure than corresponding limit values of the calibration pressure range Pset.

This switch group25also comprises an activation button31for manually closing the blocking valve11, configured to manually determine the first position26ain the slide valve26.

This switch group25also comprises a reset lever32for manually reopening the blocking valve11, this reset lever32being configured to determine the second position26bin the same slide valve26.

The by-pass group21comprises:a by-pass line35configured to put the upstream chamber13in connection with the downstream chamber14of the blocking valve11,and a three-way valve33.

Such a three-way valve33is preferably of the ‘push’ type, and comprises a manually operable by-pass button34; the three-way valve33is configured such that action on the by-pass button34results in the opening of the by-pass line35.

In particular, this three-way valve33divides the by-pass line35into two sections, an upstream by-pass section35aand a downstream by-pass section35b

The upstream by-pass section35aconnects the upstream chamber13of the blocking valve11with an inlet of the three-way valve33.

The downstream by-pass section35bconnects a downstream point, preferably the downstream chamber14, with an outlet of the three-way valve33.

This three-way valve33is configured to show:a normally open signal passage, for connection between the upstream by-pass section35aand an upstream signal line36of the upstream pressure P1;a normally closed by-pass passage, for connection between the upstream by-pass section35aand the downstream by-pass section35b.

The normally closed by-pass passage is opened by actuating the by-pass button34.

The normally open signal passage remains permanently open.

In the present embodiment, the pressure regulator24incorporates, as mentioned above, the pressure reducer22.

This pressure reducer22in turn comprises:a containment structural body40having inside it a reduction chamber41defined between an upper membrane41aand a lower membrane41b, which are fixed to the containment structural body40itself;a movable equipment42with a shutter43, this movable equipment42being fixed to the upper41aand lower41bmembranes and being placed inside the reduction chamber41;a reduction valve44placed to cross transversely the containment structural body40and the movable equipment42, this reduction valve44having an axial reduction hole44a, facing the shutter43, and an opposite counterthrust axial pin44b, resting on an internal face of the movable equipment42;an upper thrust chamber45, defined above the upper membrane41a, into which the motorization fluid enters through one or more passages defined on the shutter43;a lower thrust chamber46, defined below the lower membrane41b, inside which a calibration spring47is positioned.

The reduction valve44has an inlet mouth48and an outlet mouth49.

The pressure regulator24also comprises the pressure differential selector23.

In the embodiment of the invention described here, by way of non-limiting example of the invention itself, the pressure differential selection device23comprises:an upper pusher50, placed inside the containment structural body40and configured to operate with thrust on the movable equipment42;an upper differential selection chamber51, defined in the containment structural body40, inside which the upper pusher50is free to translate in axial direction;an upper mouth52, configured to connect the upper differential selection chamber51with the upstream signal line36;a lower pusher53, placed inside the containment structural body40and configured to operate with thrust on the movable equipment42on the opposite side with respect to the upper pusher50;a lower differential selection chamber54, defined in the containment structural body40, inside which the lower pusher53is free to translate in axial direction;a lower mouth55, configured to connect the lower differential selection chamber54with a signal line56of a supply pressure Pa of a motorization fluid entering said pressure reducer22.

In particular, in the present embodiment, the lower pusher53is interposed between the calibration spring47and the movable equipment42.

In the present embodiment, the lower differential selection chamber54coincides with the lower thrust chamber46in which the calibration spring47operates.

In the embodiment described herein, the upper pusher50comprises a first piston50aplaced to translate in the upper differential selection chamber51, wherein there is a sealing ring60configured to prevent gas leakages from the upper differential selection chamber51towards an upper vent hole61.

The first piston50adefines a thrust surface50bon which the upstream pressure P1present in the upper differential selection chamber51acts.

A thrust stem50cdevelops from the first piston50aand whose length is such that it comes into contact with the movable equipment42, and in particular with the upper end of the movable equipment42.

In the embodiment described herein, the lower pusher53comprises a second piston53aplaced to translate in the lower differential selection chamber54, wherein there is a sealing ring62configured to prevent gas leakages from the lower differential selection chamber54towards a lower vent hole63.

The second piston53adefines a thrust surface53bon which the supply pressure Pa of the motorization fluid acts.

The calibration spring47is pressed between a bottom shoulder57, fixed to the containment structural body40, and a thrust plate58.

The second piston53acomprises a first resting projection53cconfigured to rest against the thrust plate58.

The second piston53acomprises a second resting projection53dconfigured to rest against the movable equipment42.

A closing spring45ais provided in the upper thrust chamber45and which is configured to keep the movable equipment42in the closed position of the pressure reducer22in the event of a lack of pressures in the pressure reducer22itself.

In a variant embodiment of the invention, not illustrated for simplicity's sake, the upper pusher comprises a membrane element defining a motorization small chamber into which the upstream pressure P1enters, instead of a piston with a sealing ring.

In a variant embodiment of the invention, not illustrated for simplicity's sake, the lower pusher comprises a membrane element defining a motorization small chamber into which the supply pressure Pa enters, instead of a piston with a sealing ring.

The motorization fluid reaches the inlet mouth48of the reduction valve44through a supply line35c.

In the present non-limiting embodiment of the invention itself, this supply line35cis directly connected to the downstream by-pass section35b; this supply line35cdetermines the use, as a motorization fluid, of gases having a supply pressure Pa which corresponds to the pressure present in the by-pass line35between upstream chamber13and downstream chamber14, referred to as ‘by-pass pressure’; consequently, the by-pass pressure reaches through the signal line56the lower differential selection chamber54.

Similarly, also in the first variant of the blocking device110, the supply line35cis directly connected to the downstream by-pass section35b.

In the first variant of the blocking device110, the signal line156connects the lower differential selection chamber54of the pressure differential selector device123to bring therein the supply pressure Pa of a motorization fluid entering said pressure reducer122, with the supply line35cupstream of the pressure reducer122.

In such first variant of the blocking device110, the three-way valve33has a normally open signal passage configured to connect the upstream by-pass section35aand an upstream signal line136of the upstream pressure P1, wherein the upstream signal line136is connected to the upper differential selection chamber of the pressure differential selector device123.

In an alternative embodiment, schematized inFIG.6, the blocking device210comprises a supply line235cwhich is an external supply line and the motorization fluid is a fluid such as compressed air, or nitrogen from a cylinder, or other similar and equivalent fluids; this supply line235cis therefore not connected to the by-pass line35nor to other pressure lines of the blocking device10.

The supply line235cis connected to an external source290, which may be a compressed air source or a nitrogen cylinder.

In this variant embodiment, the signal line56for the lower differential selection chamber54of the pressure differential selector device23is connected to the downstream section35bof the by-pass line35, similarly to what has been described above.

This second variant embodiment can also be integrated into the first variant embodiment of the blocking device110described above.

The other components of the blocking device10, of the blocking device110in the first variant, and of the blocking device210in the second variant embodiment are intended to be the same.

A first filter59is placed on the upstream signal line36for filtering the gas coming from the upstream chamber13.

In particular, in the above-mentioned embodiments, the first filter59is positioned inside the structural body40on the passage between the upper mouth52and the upper differential selection chamber51.

A second filter65is placed on the supply line35cfor filtering the motorization fluid before it enters the pressure reducer22.

A throttling device66configured to delay the passage of the motorization fluid from the downstream section35bof the by-pass line35may also be present on the supply line35c, favoring the transit of gas from the upstream chamber13to the downstream chamber14for balancing the downstream pressure P2with the upstream pressure P1.

The operation of the blocking device10according to the invention is described below.

When there is a drop in the downstream pressure downstream of the blocking valve11below a minimum calibration pressure of the switch group25, this pressure signal reaches the pressure switch30of the switch group25, which makes the slide valve26trigger in the first position26a.

It is to be understood that the activation of the switch group25also occurs when, through the downstream signal line29, the pressure switch30detects an increase in the downstream pressure above the maximum calibration pressure of the switch group25; even in this case, the pressure switch30would trigger the slide valve in the first position26a.

The first position26aof the slide valve26causes the discharge of the fluid-dynamic actuator18and the closure of the blocking valve11.

The upstream signal line36is always pressurized at the upstream pressure P1; the pressure reducer22is therefore normally closed.

For the blocking valve11to be reset, an operator presses the by-pass button34, causing the transit of gas at the upstream pressure P1from the upstream chamber13towards the downstream chamber14.

The three-way valve33thus determines the connection between the upstream section35aof the by-pass line35with the downstream section35bof the by-pass line35itself.

The by-pass line35is crossed by pressurized gas at a by-pass pressure.

Through the supply line35c, which is directly connected to the downstream section35b, the gas at the by-pass pressure reaches the inlet mouth48of the reduction valve44of the pressure reducer22as motorization fluid, and a by-pass pressure signal reaches the lower differential selection chamber54through the supply pressure signal line56which is connected to the supply line35c.

This results therefore in a situation in which:the movable equipment42of the pressure reducer22is pushed by the upper pusher50, under the action of the upstream pressure P1, so that the closed position of the reduction valve44is maintained, with consequent no passage of motorization fluid towards the fluid-dynamic actuator18;the same movable equipment42is pushed by the lower pusher53, under the action of the supply pressure Pa, which is constituted by the by-pass pressure, or under the action of another supply pressure Pa coming from an external pneumatic line, in the opening direction of the reduction valve44.

The upper pusher50, the lower pusher53and the calibration spring47are configured in such a way that the reduction valve44opens only when the difference between the upstream pressure P1and the by-pass pressure is less than a predetermined safety value, i.e. the predetermined value of the balancing pressure difference Peq, for example below a safety pressure difference comprised between 2 bar and 4 bar.

Thanks to the pressure differential selection device23, the pressure reducer22opens and works, reducing the pressure of the motorization fluid to a motorization pressure of, for example, about 4 bar, only when the upstream pressure P1and the supply pressure Pa, which may be the by-pass pressure, or may be the downstream pressure P2, are equalized below a safety value Peq of the difference of the two pressures.

In this way, even if an operator were to operate the reset lever32inappropriately before the upstream P1and downstream P2pressures are sufficiently equalized, the fluid-dynamic actuator18would not be motorized because the pressure reducer22would remain closed and inoperative.

As a general rule, it is to be understood that the downstream pressure detected by the downstream signal line29may be different from the downstream pressure P2, which is present in the downstream chamber14of the blocking valve11, which becomes supply pressure Pa through the supply line35c, and which also reaches the lower differential selection chamber54of the differential selection device23and123through the signal line56and156; this difference in the downstream pressure at different points of the line downstream of the shutter of the blocking valve11depends on the specific configuration of the plant.

The invention also relates to a pressure regulator24, particularly for blocking devices for pipelines for the passage of pressurized gas, characterized by incorporating in a single containment structural body40a pressure reducer22and a pressure differential selection device23configured to compare two operating pressures and to operate the opening or closure of the pressure reducer22depending on the pressure difference between these two operating pressures; the pressure differential selection device23comprises two pressure differential selection chambers:an upper differential selection chamber51, supplied with a first operating pressure, defined in the containment structural body40, inside which an upper pusher50is free to translate in axial direction, in turn configured to operate with thrust on said pressure reducer22according to a first thrust direction,a lower differential selection chamber54, supplied with a second operating pressure, defined in the containment structural body40, inside which a lower pusher53is free to translate in axial direction, in turn configured to operate with thrust on said pressure reducer22according to a second thrust direction, opposite to said first thrust direction.

The pressure reducer22and the pressure differential selection device23are intended so that they can be as described above.

Any other variant in which the pressure reducer is structured differently but is technically equivalent is to be understood as being included in the invention.

In particular, the pressure regulator24is characterized in that said pressure differential selection device23comprises:an upper pusher50, placed inside the containment structural body40and configured to operate with thrust on the movable equipment42;an upper differential selection chamber51, defined in the containment structural body40, inside which the upper pusher50is free to translate in axial direction;an upper mouth52, configured to connect the upper differential selection chamber51with a first signal line of a first operating pressure;a lower pusher53, placed inside the containment structural body40and configured to operate with thrust on the movable equipment42on the opposite side with respect to the upper pusher50;a lower differential selection chamber54, defined in the containment structural body40, inside which the lower pusher53is free to translate in axial direction;a lower mouth55, configured to connect the lower differential selection chamber54with a second signal line of a second operating pressure.

It has in practice been established that the invention achieves the intended task and objects.

In particular, the invention has developed a pilot-operated blocking device in which the opening of the blocking valve is prevented until the upstream pressure and the downstream pressure are properly balanced.

In addition, the invention has developed a blocking device capable of better protecting the components placed downstream of the pressure reducer, since the slide valve is not affected by a motorization pressure, except when the upstream and downstream pressures are equalized; in fact, in case the blocking valve is activated, the control system is not supplied, since the supply pressure is taken downstream of the shutter of the blocking valve, the latter being closed. In this situation, as there is no supply pressure, there is also no motorization pressure reaching the slide valve.

In addition, the invention has developed a blocking device which is simple to install in the same way as blocking devices of the known type.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; moreover, all the details may be replaced by other technically equivalent elements.

In practice, the components and materials used, as well as the dimensions and the contingent shapes can be anyone according to the requirements and the prior art, as long as they are compatible with the specific use.

If the characteristics and techniques mentioned in any claim are followed by reference signs, these reference signs are to be intended for the sole purpose of increasing the intelligibility of the claims and, consequently, such reference signs have no limiting effect on the interpretation of each element identified by way of example by these reference signs.