System and method for monitoring and diagnosing an actuator device for actuating a valve for a fluid conduit, and an actuator device forming part of the system

Abstract

A monitoring system (500) for an on / off type actuator device (1) for activating a valve for a fluid pipeline is described. The actuator device (1) is configured to move a valve member of the valve between a first position and a second position. The actuator device (1) includes at least one fluid cylinder (6) configured to control the linear movement of an actuator rod (8). The monitoring system (500) includes a plurality of sensors and an electronic processing and control unit (50), the plurality of sensors being mounted on the actuator device (1) and configured to detect a plurality of operating parameters of the actuator device. The electronic processing and control unit (50) is configured to cause a micro-movement of the valve member, to detect a signal indicating the value of the operating parameter during the micro-movement of the valve member, and to estimate whether the actuator device (1) is able to apply a torque value or a force value sufficient to cause the valve member to perform a full movement from the first position to the second position based on the detected value of the operating parameter. The micro-movement is such that it constitutes the beginning of a movement of the movable member of the valve, corresponds only to overcoming the mechanical clearances and the dissipation and deformation effects inside the actuator (1), and furthermore does not involve substantially any modification of the fluid flow controlled by the valve. In this way, it is possible to estimate the state of health of the actuator device (1) without causing a change in the fluid flow through the aforementioned valve.

Description

Technical Field

[0001] The invention relates to a monitoring system for actuator devices for activating valves of various types, such as relatively large ball valves, butterfly valves or gate valves.

[0002] More specifically, the present invention relates to a monitoring system for an on / off type actuator device, which is used to activate a valve for a fluid pipeline, wherein the actuator device is configured to move a valve member of the valve between a first position corresponding to a normal operating state of the valve and a second position corresponding to an emergency operating state of the valve, and wherein the actuator device includes at least one fluid cylinder configured to control the linear movement of an actuator rod.

[0003] Actuator devices of the above type have been known and used for some time. Furthermore, monitoring systems for such actuators have been proposed (see, for example, document WO 2014 / 168908 A2), which provide a plurality of sensors mounted on the actuator device and configured to detect a plurality of operating parameters of the actuator device. Background Art

[0004] Prior art

[0005] In order to better understand the present invention, an example of an actuator device of the prior art to which the present invention is applicable is described below. It should be noted that the present invention is also applicable to actuator devices of the same type but with a different structure in construction, or even to any other known type of actuator device, which will become more obvious below.

[0006] refer to Figure 1 , numeral 1 denotes as a whole an actuator device for activating various types of valves, such as ball valves or butterfly valves, which is illustrated in a cross-sectional perspective view.

[0007] The actuator device 1 comprises a central supporting body 2 in the form of a metal casing, comprising an element 2A onto which a cover 2B is screwed, so as to define a closed inner cavity 3 .

[0008] The central support body 2 supports an actuator shaft 5 that rotates about a main axis 4. In the specific example illustrated, the actuator shaft 5 is made in the form of a bushing that is internally grooved to accommodate therein an actuator stem (not shown) of a movable member of the valve. The bushing constituting the actuator shaft 5 is rotatably mounted in the central support body 2 by means of any known type of sliding bearing or roller bearing.

[0009] The actuator device 1 controls the rotation of the actuator shaft 5, which in turn controls the movable member of the valve to rotate between a first position corresponding to a fully open valve, for example, and a second position corresponding to a fully closed valve, for example. According to conventional techniques, the movable part of the valve may be of a type in which a passage from the open position of the valve to the closed position occurs as it rotates 90 degrees around the main axis 4.

[0010] An end plate 6A of the body of the fluid cylinder 6 intended to control the rotation of the actuator shaft 5 is rigidly connected to one side of the central support body 2. The fluid cylinder 6 can be a hydraulic cylinder or a pneumatic cylinder. The illustrated example refers in particular to the case of a pneumatic cylinder. In any case, the fluid cylinder 6 comprises a cylinder body having an axis 6X. The axis 6X of the fluid cylinder 6 and the axis 4 of the actuator shaft 5 are not incident with each other, but are contained in a vertical plane. The cylinder body is defined by a cylindrical wall 6B, one end of which is closed by the aforementioned end plate 6A, and the opposite end is closed by an end plate 6C. In the illustrated example, the end plates 6A and 6C are clamped against the opposite ends of the cylindrical wall 6B by a plurality of spiral tie rods 6D.

[0011] The piston 7 is slidably mounted in the body of the fluid cylinder 6 and is rigidly connected to an actuator rod 8 which is slidably mounted through a central opening of the end plate 6A and a hole 9 in the side wall of the central support body 2. Thus, the actuator rod 8 extends in the cavity 3 of the central support body 2.

[0012] The actuator rod 8 of the fluid cylinder 6 is intended to control the rotation of the actuator shaft 5 by means of a pin-slot transmission, which allows the linear movement of the actuator rod 8 to be converted into a rotation of the actuator shaft 5 about the axis 4 .

[0013] For this purpose, refer to Figure 2 , an actuator arm 10 carrying a cam track in the form of a slot 11 which is engaged by a cam follower pin 12 carried by the actuator rod 8 is rigidly connected to the actuator shaft 5 .

[0014] Reference Figure 1 To Attachment Figure 4 In the example shown in FIG. 1 , the actuator arm 10 has a yoke shape with two plates 10A that are parallel and spaced apart. Figure 2 Only one of the plates is visible in the figure. Still in the particular case of the specific example illustrated, each of the plates 10A has an approximately elongated elliptical configuration, one end of which is rigidly connected to the actuator shaft 5. The rest of the body of each plate 10A has a corresponding slot 11. The slots 11 provided in the two plates 10A are identical to each other and are positioned identically. These slots 11 are engaged by the two ends of a cam follower pin 12, which is carried by a block 13 rigidly connected to the actuator rod 8. The cam follower pin 12 protrudes on opposite sides of the block 13 to engage the two slots 11 provided in the plate 10A.

[0015] As described above, the two plates 10A together constitute the actuator arm 10 of the actuator device 1. The engagement of the cam follower pin 12 in the groove 11 of the plate 10A allows the linear movement of the actuator rod 8 of the fluid cylinder 6 to be converted into the rotation of the actuator shaft 5, which transmits the rotation to the control rod (not shown) of the movable member of the valve, which is coupled in a bushing constituting the actuator shaft 5.

[0016] Of course, the construction of the actuator arm 10 described here is provided purely as an example. The actuator arm may have any other configuration, and in particular, it may consist of a single plate with a single slot engaged by a cam follower pin carried by the actuator rod of the hydraulic cylinder.

[0017] The groove 11 may also be of any form. In particular, the groove may have a straight form, or may have any non-straight profile to produce the desired relationship between the axial movement of the actuator rod 8 and the rotation of the actuator shaft 5. According to the content proposed in European patent EP 3 029 338 B1 owned by the same applicant, the actuator arm can also envisage that each groove is formed in a replaceable insert that is removably mounted in the body of the actuator arm.

[0018] Reference again Figures 1 to 4 The actuator device illustrated here purely by way of example also comprises, in a manner known per se, a fail-safe safety device for retracting the actuator arm 10 into a safe position in the event of a failure of the fluid cylinder 6 or of the pneumatic / hydraulic supply system to the fluid cylinder, or if the actuator needs to perform an emergency operation, such as an operation resulting in the closing of a valve in order to interrupt the flow into the pipeline in which the valve is installed.

[0019] Still reference Figure 1, the fail-safe safety device is indicated as a whole by reference numeral 14 and comprises a cylindrical housing 15 having an axis 15X coaxial with the axis 6X of the fluid cylinder 6. The housing 15 of the safety device 14 is rigidly connected to the central support body 2 at one of its end walls on the opposite side with respect to the fluid cylinder 6, so that the central support body 2 is interposed between the fluid cylinder 6 and the safety device 14. An actuator rod 8' is slidably mounted at an end plate 15A of the housing 15, the actuator rod 8' being arranged on an extension of the actuator rod 8 and also connected to a block 13 carrying the cam follower pin 12. The actuator rod 8' extends inside the housing 15 and is rigidly connected to a plate 16 movable inside the housing 15. In the case of the example shown, the end of the actuator rod 8' situated on the opposite side relative to the block 13 is guided in a sliding manner in a tubular member 17 which projects inside the housing 15 and is carried by an end plate 15B which closes the housing 15 on the opposite side relative to the central support body 2. One or more helical springs 18 are operatively interposed between the plate 16 and the end plate 15B, which tend to retract the actuator rod 8' into an end position corresponding to the safety position of the actuator arm 10.

[0020] Still reference Figures 1 to 4 , the central support body 2 is provided with a guide rod 19 which is integrally mounted with the central support body 2 and extends in a direction parallel to the axes 6X and 15X of the actuator rods 8 and 8'. For example, the block 13 carrying the pin 12 is slidably guided on the guide rod 19 by receiving the guide rod 19 in a through hole extending through the block 13 in a direction perpendicular to the pin 12. In this way, when the block 13 moves under the action of the actuator rod 8 or 8', the pin 12 is constrained to extend along an almost straight path parallel to the axes 6X and 15X.

[0021] As mentioned previously, it is known in the art to provide valve actuator devices equipped with at least one sensor for detecting the value of at least one operating parameter of the actuator during its operation, so as to allow monitoring of the actuator.

[0022] For example, document WO 2014 / 168908 A2 already mentioned above describes an actuator for a process valve comprising a vibration sensor associated with the actuator, and a process control system for determining the health state of the actuator from values ​​detected by the vibration sensor during normal operation of the actuator.

[0023] Technical issues

[0024] References Figures 1 to 4The described actuator devices, as well as linear actuator devices for activating gate valves, are often used as "on / off" type actuators in critical applications where they are used to perform emergency functions (e.g. fully close the corresponding valve within a predetermined maximum time).

[0025] In an on / off type actuator arrangement, the actuator:

[0026] - can typically present only two positions (e.g. fully open and fully closed),

[0027] - is normally in one of these two positions (e.g., fully open), and

[0028] - When activated, it performs a safety function by moving to a position opposite to the normal position (e.g., completing full closure of the valve).

[0029] refer to Figures 1 to 4 As a non-limiting example, the actuator device 1 used as an on / off type actuator is usually in a state where the fluid cylinder 6 is kept under pressure and the piston 7 is close to the end plate 6A to overcome the force applied by the spring 18, which is compressed between the end plate 15B and the plate 16 in the cylindrical housing 15. When emergency operation is required, the fluid cylinder 6 is released, so that the force applied by the spring 18 on the plate 16 exceeds the force applied by the fluid cylinder 6 in the opposite direction and the rotation resistance (e.g., friction) caused by the valve, resulting in the linear movement of the actuator rods 8 and 8' toward their rest positions, which is converted into a rotation of the actuator shaft 5 corresponding to the valve closing.

[0030] Typically, the frequency of intervention of the actuator device required to perform an emergency maneuver is about once a year, or even less. Given the critical nature of the emergency functions performed by this type of actuator, the problem arises of ensuring a high level of reliability of the actuator device and maintaining this reliability level over time. However, the low frequency with which the actuator must intervene makes it difficult to diagnose the actual ability to perform an emergency maneuver. Due to this nature of on / off type actuators, the possibility of verifying the actual operation of the actuator with high frequency during normal operation is practically excluded.

[0031] According to the functional safety standards IEC61508 IEC61511 (or according to ISO13489 or EN62061), monitoring systems for actuators of the on / off type and for decisive elements are available on the market, in which the health state of the actuator device is controlled by periodically operating the actuator device, thereby achieving a macroscopic movement of the valve member associated therewith. For example, if the valve is of the normally open type, the actuator can be controlled to at least partially close the valve for monitoring purposes, which forces a temporary reduction in the flow through the pipeline, which, although for a limited time, leads to economic losses due to a reduction in the output of the equipment; these systems are said to interfere with industrial processes.

[0032] An example of a device requiring macroscopic movement of a valve member in order to check the health of the valve is shown in European patent application published as EP 3 527 834 A1 (filed earlier but published after the priority date of the present application and therefore forming part of the prior art specifically for the purposes of Article 54(3) of the European Patent Convention).

[0033] The aforementioned document EP 3 527 834 A1 describes a method for determining the operability of a safety valve activated by a fluid actuator. The method comprises:

[0034] - perform a partial closing operation of the safety valve ("partial stroke test"), simultaneously detecting the pressure of the fluid in the fluid actuator and the position of the safety valve, i.e. its closing percentage,

[0035] - determining the correlation curve between the position of the safety valve and the pressure of the fluid in the fluid actuator,

[0036] - linear extrapolation of the trend of the correlation curve, and

[0037] - Based on the extrapolation, a pressure value of the fluid in the fluid actuator corresponding to a safety position of the safety valve is determined.

[0038] Therefore, the solution described in EP 3 527 834 A1 also requires moving the valve member, which disturbs the flow of the fluid through the conduit in which the valve is located, resulting in the disadvantages already listed above.

[0039] Furthermore, known monitoring systems are typically based on an approach in which the actuator is declared in good health if the actuator is able to cause the valve member to perform a macroscopic but partial movement (e.g., approximately 15 to 20 degrees of rotation) based on reaching one or more thresholds defined by the operator's experience.

[0040] Furthermore, in the event that the actuator fails to successfully perform a control maneuver (i.e., part of a macroscopic movement), known monitoring systems do not provide any indication of the possible cause of the actuator failure, therefore relying entirely on the operator's experience for a possible analysis of the values ​​of the detected operating parameters, and leading (in the event of a detected anomaly) to prolonged downtime of the system and complex maintenance procedures, which are often onerous (e.g., replacement of the entire actuator device).

[0041] Purpose of the invention

[0042] The object of the present invention is to provide a monitoring system for an on / off type actuator device, which is used to activate a valve for a fluid pipeline, and the monitoring system allows the performance reliability of the actuator device to be diagnosed at an appropriate frequency (for example, a higher frequency than the frequency currently commonly used to monitor on / off type devices) without adversely affecting the industrial process, and in particular without interfering with the flow of fluid through the pipeline in which the valve is located.

[0043] It is another object of the present invention to preferably also estimate the time required for the valve member to complete movement from the open position to the closed position. Summary of the invention

[0044] In order to achieve the above-mentioned objects, the present invention relates to a monitoring system for an on / off type actuator device for activating a valve, the monitoring system having all the characteristics indicated at the beginning of this description and being further characterized in that:

[0045] - a plurality of sensors mounted on the actuator device including at least one pressure sensor for detecting the pressure in the fluid cylinder, a temperature sensor for detecting the temperature in the fluid cylinder, a linear position sensor for detecting the linear position of the actuator rod, and one or more deformation sensors of one or more components of the actuator;

[0046] - The monitoring system comprises an electronic processing and control unit configured to:

[0047] - activating the actuator means to cause a micro-movement of the valve member,

[0048] - during micro-movements of the valve member, detecting by a plurality of sensors signals indicative of the values ​​of said operating parameters, and

[0049] - estimating, based on the value of the operating parameter detected during the micro-movement of the valve member, whether the actuator device is able to apply a torque value or a force value sufficient for the valve member to perform a full movement from the first position to the second position,

[0050] - said micro-movement is such as to constitute the beginning of a movement of the movable member of the valve, corresponds only to overcoming mechanical play and dissipative and deformation effects inside the actuator and, moreover, is such as not to involve substantially any modification of the flow of the fluid controlled by the valve; and

[0051] - The steps of detecting the sensor signal and estimating the torque value or force value that can be applied by the actuator device are automatically activated immediately after the micro-movement is performed.

[0052] The invention thus allows real-time diagnostics of actuator devices at moderate (even high) frequencies without adversely affecting the industrial process, since the diagnostic procedures involve performing micro-movements that do not substantially disturb the fluid flow controlled by the valve itself.

[0053] The electronic processing and control unit can be programmed in any predetermined manner so as to use the parameter values ​​detected by the above-mentioned sensors to provide an indication of the health of the system, in particular the ability of the actuator device to perform the entire movement of the valve member from the first position to the second position. As described in detail below, the mathematical model that can be used for this type of evaluation can be constructed with increasing complexity, depending on the degree of accuracy to be obtained. In an extremely simplified case, for example, any algorithm that links a single operating parameter (e.g., the pressure in the actuator cylinder and the kinematic transmission characteristics between the actuator rod and the movable valve member) to the torque value transmitted to the latter can be used. It is also not excluded to use a parameter map (lookup table) that provides an indication of the health of the system based on the parameters detected by the sensor.

[0054] In any case, as will become apparent from the following description, it is important to note that the core of the invention does not lie in any particular estimation method, but in the understanding of the possibility of performing this estimation based on the parameter value detected by the aforementioned sensor after a small movement of the valve member, which small movement constitutes only the beginning of a movement of the movable member of the valve, corresponding only to overcoming the mechanical clearances inside the actuator and the dissipation and deformation effects, but at the same time making it substantially avoid causing any change in the fluid flow controlled by the valve.

[0055] It should be noted that in reference Figures 1 to 4 In the case of an actuator arrangement of the type illustrated (so called "quarter turn / quarter turn"), a micro-movement of the valve member is to be understood as a micro-rotation and the parameter to be estimated may be the torque applied to the valve member.

[0056] Alternatively, in the case of a linear actuator device for moving a "gate" type valve (to which the present invention also applies), micro-movements of the valve member will be understood as micro-translations and the parameter estimated may be the force applied to the valve member.

[0057] In a preferred embodiment, the electronic processing and control unit is further configured to estimate the time required for the valve member to complete a full movement from the first position to the second position based on the value of the operating parameter detected during the micro-movement of the valve member.

[0058] In a preferred embodiment, the actuator device is configured to rotate the valve member between a first position and a second position and includes an actuator shaft for controlling the rotation of the valve member and a transmission device for converting the linear movement of the actuator rod into the rotation of the actuator shaft. In this preferred embodiment, the plurality of sensors includes an angular position sensor for detecting the angular position of the actuator shaft.

[0059] In another preferred embodiment, the electronic processing and control unit is configured as follows:

[0060] - calculating an applyable torque value or force value that the actuator device can apply to the valve member when the actuator device is controlled to cause the valve member to perform a complete movement from the first position to the second position,

[0061] - calculating the resisting torque or force required to actually move the valve member from the first position to the second position,

[0062] - comparing the applicable torque value or force value with a minimum reference value, and / or, comparing the resisting torque value or force value with a maximum reference value,

[0063] - if the value of the applicable torque or force is below the minimum reference value, generating a signal indicating an abnormality of the actuator device, and

[0064] - If said resisting torque value or force value is higher than said maximum reference value, a signal indicating a valve anomaly is generated.

[0065] In a preferred embodiment, the electronic processing and control unit is configured to identify at least one component or subunit of the actuator device causing the applyable torque or force value to fall below the minimum reference value due to the applyable torque or force value falling below the minimum reference value.

[0066] In a preferred embodiment, the electro-pneumatic control unit is associated with the actuator device, and the electronic processing and control unit is configured to identify at least one component or sub-unit of the electro-pneumatic control unit that causes the calculated torque value to be lower than the reference torque value due to the applicable torque value or force value being lower than the minimum reference value.

[0067] Further preferred features and advantages of the invention are pointed out in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Other characteristics and advantages of the invention will become apparent from the following description made with reference to the accompanying drawings, which are provided purely as non-limiting examples and in which:

[0069] - Already described above Figure 1 is a cross-sectional perspective view of an actuator device for activating a valve,

[0070] - Already described above Figure 2 for Figure 1 A cross-sectional view of a central support body of an actuator device including a mechanism for transmitting motion to an actuator stem of a valve,

[0071] - Already described above Figure 3 and Figure 4 To show Figure 2 A perspective view of some implementation details of the transmission mechanism,

[0072] - Figure 5 is an exemplary block diagram of a monitoring system according to the present invention,

[0073] - Figure 6 is a cross-sectional view of an actuator device according to the present invention,

[0074] - Figure 7 is another cross-sectional view of an actuator device according to the present invention, and

[0075] - Figure 8 is an exemplary flow chart of a method for monitoring a valve actuator according to the present invention. DETAILED DESCRIPTION

[0076] exist Figure 5 In the non-limiting example shown, a monitoring system 500 for an on / off type actuator device 1 according to the invention comprises:

[0077] a plurality of sensors mounted on the actuator device 1 and configured to detect a plurality of operating parameters of the actuator device 1,

[0078] - an electronic processing and control unit 50,

[0079] - a human machine interface device (HMI) 52,

[0080] - an electro-pneumatic control unit 54, and

[0081] - Optionally, a remote equipment control room 56 .

[0082] According to the present invention, the actuator device 1 can be a reference Figures 1 to 4 An actuator device of the type shown, or more precisely, comprises a single-acting fluid cylinder 6, which is usually used to maintain the valve member in a first operating position (typically, fully open), and at least one spring element 18, which tends to move (e.g. rotate) the valve member towards a second safe operating position (typically, fully closed).

[0083] In an alternative embodiment, the actuator device 1 may include a double-acting fluid cylinder which can be activated in one direction to move (e.g. rotate) the valve member towards its first position, and in an opposite direction to move (e.g. rotate) the valve member towards its second position.

[0084] In yet another alternative embodiment, the actuator device 1 may include a first single-acting cylinder and a second single-acting cylinder, wherein the first single-acting cylinder can be activated to move (e.g., rotate) the valve member toward its first position, and the second single-acting cylinder can be activated to move (e.g., rotate) the valve member toward its second position.

[0085] The electronic processing and control unit 50 is configured to receive, from a plurality of sensors mounted on the actuator device 1 , respective signals indicative of values ​​of operating parameters detected on the actuator device 1 .

[0086] Furthermore, the electronic processing and control unit 50 is configured to give the electro-pneumatic control unit 54 the commands required to activate the actuator device 1, such as, for example, a command to open or close (totally or partially) a valve, or a set of commands to activate and execute a program for diagnosing the health state of the actuator 1, as better described in the following parts of the present description.

[0087] The electropneumatic control unit 54 comprises a set of electropneumatic valves implementing an electropneumatic circuit for controlling the fluid cylinder 6 , these electropneumatic valves being controlled by the electronic processing and control unit 50 .

[0088] For example, the electro-pneumatic control unit 54 may include:

[0089] - an inlet conduit for a pressurized fluid (e.g. air) with a corresponding inlet filter,

[0090] - a pressure regulating device in the inlet pipe downstream of the inlet filter,

[0091] - a pressure limiting device which performs a safety function by limiting the pressure downstream of the pressure regulating device,

[0092] - a (proportional) flow rate regulating device for regulating the fluid entering the fluid cylinder 6,

[0093] - a flow amplifier device downstream of the flow regulator device, which supplies liquid to the pneumatic outlet conduit connected to the inlet of the fluid cylinder 6 in order to control its actuation, and

[0094] - Means for releasing the actuator 1 in emergency situations.

[0095] In the remainder of this specification, reference will be made by way of non-limiting examples to the following Figures 1 to 4The actuator arrangement shown is an actuator arrangement configured to produce a rotational movement of a valve member, it being understood that the principles of the present invention are equally applicable to an actuator arrangement for a gate valve.

[0096] According to the invention, the electronic processing and control unit 50 is configured to execute a diagnostic procedure of the actuator 1 comprising:

[0097] - activating the actuator device 1 by means of the electropneumatic control unit 54 so as to produce a micro-rotation of the actuator shaft 5 so as not to disturb the flow of the fluid controlled by the valve (possibly a set or a series of micro-rotations),

[0098] - during a micro-rotation of the actuator shaft 5 , a signal indicating the value of an operating parameter is detected by a plurality of sensors mounted on the actuator 1 , and

[0099] - from the value of said operating parameter detected during said micro-rotation of the actuator shaft 5, estimating whether said actuator device 1 is able to apply a torque value sufficient for the valve member to perform a complete movement from the first position to the second position.

[0100] For example, this estimation can be done as follows:

[0101] - calculating the value of the torque that the actuator shaft 5 can apply to the valve member if the actuator device 1 is controlled so that the valve member performs a complete movement from the first position to the second position, and

[0102] - comparing the torque value thus calculated with a threshold torque value required for effective rotation of the valve member from the first position to the second position.

[0103] If it is detected that the actuator arrangement 1 is unable to apply a torque value sufficient for the valve member to perform a full movement from the first position to the second position (eg because the calculated torque value is less than a threshold torque value), the monitoring system may generate a signal indicating an abnormality.

[0104] At the end of the above-described diagnostic routine, and if no anomalies are detected, the electronic processing and control unit 50 may, if necessary, operate the actuator 1 to return the valve member to its normal operating position.

[0105] In the embodiment illustrated here, the electronic processing and control unit 50 is mounted in the vicinity of the actuator device 1 and is configured to operate (ie receive signals and issue commands) only on this actuator device 1 .

[0106] Alternatively, the electronic processing and control unit 50 may be remotely connected to the actuator device 1 through a wired or wireless connection. For example, the electronic processing and control unit 50 may be located in a remote equipment control room 56.

[0107] In yet another alternative embodiment, a single remote electronic processing and control unit 50 may be associated with a plurality of actuator devices 1 within a certain production facility.

[0108] Where a single electronic processing and control unit 50 is associated with a plurality of actuator arrangements, the unit 50 may be configured to perform diagnostic routines cyclically ("in turn") on all actuators or groups thereof with which it is associated.

[0109] The human-machine interface device 52 associated with the electronic processing and control unit 50, in addition to providing information and commands typically available for managing actuators of known types (e.g., operating the actuator device to impart a partial rotation to the actuator shaft, and / or activating the actuator device to move the valve member from a first position to a second position), is also configured to:

[0110] - transmitting to the operator the value of the operating parameter detected on the corresponding actuator device 1,

[0111] - providing a command to activate the actuator device 1 in order to carry out the above-mentioned diagnostic procedure, and

[0112] - transmitting an alarm message corresponding to an indication of an anomaly arising if the value of the torque that the actuator shaft 5 is able to apply to the valve member is less than the value of the torque required for effective rotation of the valve from its first position to its second position.

[0113] The human-machine interface device 52 may be local, i.e. installed near the actuator device 1 and accessible by an operator on site, or the human-machine interface device 52 may be remote (i.e. connected to the electronic processing and control unit 50 via a wired or wireless connection) and located, for example, in a remote control room 56. The human-machine interface device 52 may also include a portable device, such as a smartphone or a tablet computer. Obviously, these interface devices are not mutually exclusive, and a certain actuator device 1 may be accessed by both a local interface device and a remote interface device at the same time.

[0114] Furthermore, a single remote interface device 52 may allow access to (ie, receiving data and / or sending commands to) multiple actuator devices 1 located within, for example, the same production facility.

[0115] exist Figure 6 and Figure 7 In the non-limiting example shown, the plurality of sensors mounted on the actuator device 1 include at least one of the following:

[0116] - a pressure sensor 60 for detecting the pressure in the fluid cylinder 6,

[0117] - a temperature sensor 61 for detecting the temperature in the fluid cylinder 6,

[0118] a linear position sensor 62 for detecting the linear position of the actuator rod 8,

[0119] an angular position sensor 63 detecting the angular position of the actuator shaft 5,

[0120] - a deformation sensor detecting a deformation of one or more components of the actuator,

[0121] a temperature sensor 65 for detecting the temperature at the spring element 18, and

[0122] A load cell sensor 66 detecting the force exerted by the spring element 18 on the actuator rod 8 ′.

[0123] Each of the aforementioned sensors may be implemented according to any known technology. For example, the temperature sensor may consist of a thermocouple, and the position / deformation sensor may consist of a laser sensor configured to detect the distance between the sensor and the controlled element.

[0124] In a preferred embodiment, the electronic processing and control unit 50 is further configured to estimate the time required for the valve member to complete the entire movement from the first position to the second position.

[0125] In a preferred embodiment, the electronic processing and control unit 50 is configured to:

[0126] - calculating the value of the applicable torque or force that the actuator device (1) can apply to the valve member if the actuator device is controlled to cause the valve member to perform a complete movement from the first position to the second position, and

[0127] - Calculating the resisting torque value or force value required for the actual movement of the valve member from the first position to the second position.

[0128] For example, the applicable torque value and the resisting torque value can be calculated by determining the correlation between the value of the operating parameter detected during a micro-rotation of the actuator shaft 5 and the value of the operating parameter detected during the rotation of the shaft actuator 5 for rotating the valve member from its first position to its second position.

[0129] Typically, the diagnosis can be made by comparing the torque value that the actuator can apply during the emergency maneuver with the resisting torque value.

[0130] In a preferred embodiment, in the case where the applicable torque value is lower than the resistance torque value, the electronic processing and control unit 50 is configured to determine whether an increase in internal dissipation sources of the actuator 1 has occurred (for example, increased friction of the seal, mechanical clearance due to wear, reduced thrust of the spring 18, etc.), which indicates the reason for the failure to meet the required performance, or if the performance of the actuator 1 has not deteriorated, but a gradual increase in the resistance torque value required by the valve is detected, which is attributed to the failure to meet the required performance.

[0131] Therefore, in a preferred embodiment, the electronic processing and control unit 50 is configured to:

[0132] - comparing the value of the applicable torque with a minimum reference value, and / or, comparing the value of the resisting torque with a maximum reference value,

[0133] - if the value of the applicable torque is below the minimum reference value, a signal indicating an abnormality of the actuator device 1 is generated, and

[0134] - If the resistance torque value is higher than the maximum reference value, a signal indicating a valve abnormality is generated.

[0135] In the event that the dissipation sources inside the actuator 1 have increased (i.e., in the event that the applicable torque value is less than the minimum reference value), the electronic processing and control unit 50 can be configured to identify which major subsystem of the actuator 1 (i.e., the fluid cylinder 6, the spring actuator unit 14 or the motion transmission mechanism contained in the support body 2) has caused the performance of the actuator to decrease (i.e., the actual transmittable torque is reduced).

[0136] As mentioned above, the electro-pneumatic control unit 54 may be associated with the actuator device 1. Therefore, in another preferred embodiment, the electronic processing and control unit 50 is configured to identify at least one component or subunit of the electro-pneumatic control unit 54 that causes the torque value that the actuator shaft 5 can apply to the valve member to be lower than the minimum reference value due to the implementation of the torque value that the actuator shaft 5 can apply to the valve member being lower than the minimum reference value, and to distinguish as much as possible whether the actuator device 1 or the electro-pneumatic control unit 54 causes this abnormality.

[0137] Of course, the monitoring system according to the invention may also allow maintenance operations to be performed based on the continuous detection of the value of one or more operating parameters of the actuator 1 (e.g. to detect the occurrence of wear phenomena that do not affect the emergency functions of the actuator). For example, the monitoring system may be configured as follows:

[0138] - continuously detecting the value and / or the corresponding variation of one or more operating parameters of the actuator 1 (for example, using the excitation of the mechanical system caused by any line vibration or any variation of the ambient temperature, without however introducing a disturbance of the static / dynamic state of the actuator, such as a micro-rotation),

[0139] - Perform self-diagnostics of the monitoring system, for example by checking the health of sensors and communication systems, and / or

[0140] - Monitoring the time evolution of one or more controlled parameter hypothetical values ​​(eg in order to detect drift errors).

[0141] The monitoring method according to the present invention is Figure 8 The flowchart is given as an example.

[0142] After the start step 800 , in step 801 the monitoring system issues a command to the actuator device 1 to perform a micro movement and starts detecting the value of an operating parameter.

[0143] In step 802 , the monitoring system checks, based on the detected values, whether the movable part of the valve has been switched from the static state to the dynamic state, ie, whether the given actuation command is sufficient to move the movable part of the valve.

[0144] In case of a negative result (N) of the verification step 802 indicating that the issued actuation command produces at most an elastic deformation in the kinematic chain of the actuator device without producing an effective movement of the movable member of the valve, in step 803, the monitoring system processes the acquired data and generates, in step 804, an abnormality signal indicating, for example, which unit, subunit or sensor of the actuator device 1 is the cause of the detected abnormality. The monitoring method then ends in an end step 805.

[0145] In case of a positive result (Y) of the verification step 802 indicating that the issued actuation command has produced an effective micro-movement of the movable member of the valve, at step 806 the monitoring system processes the acquired data, for example by making a predictive evaluation of at least one of the following:

[0146] - a torque value or a force value that the actuator device 1 can apply to the valve member when the actuator device 1 has to move the valve member from the first position to the second position,

[0147] - the resistance torque or force value of the movable member of the valve, and

[0148] - A value of the speed or angular velocity with which the actuator device 1 moves the valve member from the first position to the second position.

[0149] At step 807, the monitoring system generates a status signal indicating that the diagnostic routine can be executed correctly.

[0150] In step 808, the monitoring system verifies whether the estimated torque value or force value applied by the actuator device 1 to the valve member is greater than the torque value or force value (resisting torque value or force) required for effective movement of the valve member from the first position to the second position, and optionally checks whether the speed or angular velocity value at which the actuator device 1 moves the valve member from the first position to the second position is greater than a reference speed or reference angular velocity value.

[0151] In case of a negative result (N) of the verification step 808 , the monitoring system generates an abnormality signal in step 809 , and the monitoring method ends in the end step 805 .

[0152] In case of a positive result (Y) of verification step 808, at step 810 the monitoring system generates a positive status signal indicating that the actuator device 1 can perform emergency maneuvers when necessary, and the monitoring procedure restarts from start step 800, for example, to repeat the monitoring procedure regularly.

[0153] Definition of micro-movement, micro-rotation, and micro-translation

[0154] In the context of this specification, the term "micro-movement" of the valve member (or more precisely, micro-rotation of the actuator shaft 5 in the case of a "quarter-turn / quarter-turn" actuator arrangement, such as Figures 1 to 4 , or a micro-translation in the case of a linear actuator device) represents a movement that is large enough to effectively initiate the movable member of the valve (taking into account the presence of mechanical clearances and dissipation and deformation effects inside the actuator, so that a small linear movement of the actuator rods 8 and 8' does not necessarily correspond to an effective movement of the movable member of the valve), but is also small enough not to disturb the fluid dynamic characteristics of the valve in a perceptible way (for example, keeping the pipeline flow rate at the valve substantially unchanged). Therefore, this is only the "start" of the movement of the movable member of the valve, corresponding to overcoming the mechanical clearances and dissipation and deformation effects inside the actuator, and thus does not substantially involve any change in the fluid flow controlled by the valve. It must be understood from this that the above-mentioned micro-movement does not, on the one hand, cause any significant or noticeable changes in the fluid flow controlled by the valve, and on the other hand it guarantees the reliability of the valve, since each opening / closing operation of the valve causes impurities to accumulate between the valve member and the valve body.

[0155] Prediction mathematical model

[0156] In one example, the electronic processing and control unit 50 can be configured to calculate a torque value that the actuator shaft 5 can apply to the valve member based on the value of an operating parameter detected during micro-movement of the valve member through a mathematical model of the specific actuator 1, and the torque value can be stored in a memory of the processing and control unit 50.

[0157] In the case where a single electronic processing and control unit 50 is associated with multiple actuator devices, the electronic processing and control unit 50 can store multiple corresponding mathematical models of the actuator devices, for example, by associating a corresponding mathematical model with each actuator device, or by dividing the multiple actuator devices into groups (for example, each group includes a certain number of similar actuators) and associating a corresponding mathematical model with each group identified thereby.

[0158] The inventors have noticed that in order to estimate the ability of the actuator device 1 to perform an emergency maneuver (i.e. to estimate the performance of the actuator), it is useful to estimate the torque that the actuator can transmit at a given angular velocity. This angular velocity is determined by the (predetermined) maximum time allowed to rotate the movable member of the valve by approximately 90 degrees. In fact, the inventors have noticed that the dynamic effects are not negligible.

[0159] Referring to the conventional actuator device 1, as Figures 1 to 4 As shown, for example, based on the transmittable torque, the characteristics of the various parts of the actuator and the possible consequences of a relative failure on the overall characteristics of the actuator can be studied in detail. Obviously, in various embodiments of the present invention, the same method can also be applied to linear actuators to estimate the possible consequences of a failure in terms of transmittable force or thrust.

[0160] For the purposes of the present invention, the mathematical model describing the behavior of the actuator device 1 can be determined according to different methodologies.

[0161] For example, the document “Models of control valve and actuation system for dynamics analysis of steam turbines”, M. Pondini, V. Colla, A. Signorini, Applied Energy 207 (2017), pp. 208-217, doi: 10.1016 / j.apenergy.2017.05.117 and the document “Parametric identification of aservo-hydraulic actuator for real-time hybrid simulation”, Y. Qian, G. Ou, A. Maghareh, S. J. Dyke, Mechanical Systems and Signal Processing (Mechanical Systems and Signal Processing) 48 (2014), pp. 260-273, doi:10.1016 / j.ymssp.2014.03.001, is an example of a possible approach to mathematically modeling and simulating a hydraulic actuator device.

[0162] In addition or alternatively, a “digital twin” technique can also be used to determine the mathematical model of the actuator device 1. In this context, the document “A Simulation-Based Digital Twin for Model-Driven Health Monitoring and Predictive Maintenance of an Automotive Braking System”, R.Magargle, L.Johnson, P.Mandloi, P.Davoudabadi, O.Kesarkar, S.Krishnaswamy, J.Batteh, A.Pitchaikani, Proceedings of the 12th International ModelicaConference, May 15-17, 2017, Prague, Czech Republic, pp. 35-46, doi:10.3384 / ecp1713235, is an example of a “digital twin” modeling approach for complex mechanical and hydraulic systems.

[0163] By way of example, the actuator device 1 of the example considered here can be conceptually divided into three main subsystems corresponding to the fluid cylinder 6 , the spring actuator unit 14 and the pin-and-slot transmission mechanism contained in the support body 2 .

[0164] Preferably, each of the three subsystems can be further divided into a set of corresponding components (e.g., in a pin-slot transmission, the actuator arm 10, the cam follower pin 12, the block 13, the guide rod 19 and other components can be identified) by means of a failure mode, effects and diagnostic analysis (FMEDA). The possible failure modes of each of these components or subunits (e.g., groups of components) can then be analyzed to determine their influence on the characteristics of the entire actuator (e.g., in terms of variations in the transmitted torque). Thus, the mathematical model can allow the actuator device 1 to be characterized at the level of the subunits or components.

[0165] The inventors have therefore observed that, from a maintenance point of view, it is useful to identify some operating parameters of the actuator device 1 that are indicative of the state of health of one or more components or subunits of the actuator 1 to be monitored by a plurality of sensors in order to assess the ability of the actuator to perform emergency maneuvers within a certain defined time interval.

[0166] A mathematical model of the actuator device 1 may be generated based on considerations that take into account the deformability of the mechanical bodies in the actuator 1 , the influence of dynamic loads, the dynamic response of the mechanical and electro-pneumatic systems, and the actual fluid dynamics.

[0167] To generate torque, Figures 1 to 4 The illustrated actuator arrangement (with a Scotch yoke structure and a single-acting cylinder) converts a force generated by a fluid cylinder 6 and a spring element 18. This torque varies according to the angular position of the Scotch yoke kinematic mechanism (i.e., the actuator arm 10). The modulus of the torque is a function of the "gain" parameter of the kinematic mechanism, which amplifies the force.

[0168] When the actuator device 1 is required to perform an emergency maneuver, a decompression of the fluid cylinder 6 is performed, causing the piston force (F 活塞 ) is sufficient to produce a force (F) generated by spring 18 at a particular angular position (θ) of actuator arm 10. 弹簧 ) and the rotational resistance generated by the valve (e.g., due to friction), which is equal to the Δ force.

[0169] The component Δ force can be resolved in the directions of interest, or more precisely, in a first direction perpendicular to the axes 6X and 15X and in a second direction perpendicular to a line tangent to the contact profile. The contact profile is a curve that depends on the geometry of the slot 11 formed in the actuator arm 10, and the direction perpendicular to this profile varies depending on the angular position θ of the actuator arm 10. In the direction perpendicular to the axes 6X and 15X, a reaction force (F 反作用 ) balanced force. A force F is generated in the direction perpendicular to the contact contour. 合力 .

[0170] After the orientation of the actuator arm 10 has been determined (ie the orientation given by a line passing through the pin 12 and the axis of rotation 4), F 合力 Decompose it into a component perpendicular to the arm (Arm) and a component parallel to the direction, and determine the force (F) that produces the ideal torque (ignoring internal dissipation) 扭矩 ), torque 理想 Equal to: Torque 理想 =F 扭矩 x Arm, where Arm is the distance between the pin 12 and the axis of rotation 4 , which takes different values ​​depending on the angular position of the actuator arm 10 .

[0171] Therefore, the transmission mechanism causes the torque to develop from Δ force to F 扭矩 The force "multiplication", Δ force and F 扭矩 The ratio of represents the “gain” parameter and is therefore a function of the angular position θ of the actuator arm 10 .

[0172] The ideal torque can be obtained by 理想 , applying the efficiency factor η to calculate the developed torque, which takes into account the dissipation inside the actuator (due to friction) estimated experimentally or defined empirically:

[0173] Torque 实际 =ηx torque 理想 .

[0174] Calculating the torque as described above does not take into account some practical influences that would allow a more accurate estimation of the actual torque generated by the actuator device 1 when the operator performs an emergency maneuver.

[0175] For example, the calculation of the above-mentioned "gain" parameter is based on the assumption that the force generated by the contact between the pin 12 and the slot 11 depends only on the profile curve (see in this respect the aforementioned European patent EP 3 029 338 B1 owned by the same applicant), which is understood as a set of positions taken by the center of the pin 12 for each value of the angular position θ of the actuator arm 10. The geometry of the pin 12 (in the plane) is not taken into account, which geometry can produce a real contact point different from the theoretical contact point. The real contact point can also depend on the deformation state of the component concerned (and therefore on the exchanged forces and, cascade, on the operating state of the actuator 1). However, it is not considered that the deformation state of the components (for example, the deformation state of the pin 12, the block 13 and the actuator arm 10) leads to a change in the value of the geometric arm Arm and therefore to a change in the value of the torque generated.

[0176] Other practical influences not taken into account in the above model relate to the estimation of the efficiency coefficient η, whereby preferably the effective dissipation at the sliding surface, or more precisely the friction dissipation, generated by the actual contact pressure is estimated. The actual contact pressure is influenced by the actual deformation / operating state of the actuator 1. It is also appropriate to take into account other possible sources of performance losses, for example possible changes in the stiffness of the spring 18 and / or leakage of the piston sealing element 7 due to wear.

[0177] Therefore, a predictive mathematical model can be developed in order to represent the operation of the actuator 1 in the most realistic way possible and to estimate the performance of the actuator 1 as a function of operating conditions (and not just geometrical and / or kinematic parameters).

[0178] According to the invention, the mathematical model allows the actual torque, ie the torque 实际 , to estimate the actual torque, that is, the torque 实际, which can be a function not only of the pressure in the fluid cylinder 6 and the angular position θ of the actuator arm 10, but also of other parameters such as the linear position of the actuator rod 8, the temperature in the fluid cylinder 6 and / or the spring container unit 14, the deformation of one or more components of the actuator, and possible other operating parameters of the actuator 1.

[0179] The monitoring system according to the invention therefore comprises a plurality of sensors measuring some parameters indicative of the operating state of the actuator 1 useful for estimating the actual torque.

[0180] In particular, the mathematical model is based on a lumped parameter model in which the mathematical laws governing the operation of the actuator device 1 and its electropneumatic control unit 54 are represented. The lumped parameter model is fed with information obtained from simulations using specific software, for example, by finite element analysis (FEM) or computational fluid dynamics (CFD) analysis of one or more components of the actuator 1. These simulations allow the ability to represent and numerically solve some three-dimensional phenomena such as stresses, deformations, contact pressure distribution, etc.

[0181] Processing of data provided by software simulations (FEM and / or CFD) in order to integrate them into lumped parameter models, for example by generating interpolation curves, characterization matrices and transfer functions.

[0182] The predictive mathematical model according to the invention therefore allows determining a “transfer function” between a certain number of operating parameters of the actuator 1 (e.g. the pressure in the cylinder 6, the temperature in the cylinder 6, the thrust provided by the spring 18, the angular position of the actuator arm 10, etc.) and the performance of the actuator 1, depending on the torque that can be transmitted during an emergency maneuver.

[0183] As previously mentioned, the diagnostic procedure carried out by the monitoring system according to the invention thus envisages a controlled micro-movement of the actuator device 1 , substantially without requiring any change in the process, but sufficient to bring the valve into a state in which only a movement is initiated.

[0184] The mathematical model of the actuator 1 stored in the processing and control unit 50 allows to relate the values ​​of the operating parameters detected during this portion of disturbance-free micro-movement to the values ​​that the actuator 1 is estimated to have during a hypothetical execution of the emergency function. The mathematical model therefore allows to estimate the actual torque that the actuator 1 is able to transmit during the emergency maneuver, from the estimated values ​​of these operating parameters.

[0185] As expected, the here described example of a so-called "quarter-turn / quarter-turn" actuator arrangement (i.e., an actuator arrangement configured to convert the linear movement of the actuator stem 8 into the rotational movement of the actuator shaft 5 so as to rotate the valve member associated therewith) should not be construed as limiting the embodiments of the present invention. In fact, the various embodiments may be equally applicable to so-called "linear" actuator arrangements, in which the linear movement of the actuator stem 8 is directly transmitted to the movable member of the gate valve so as to cause it to move from a first position to a second position, in effect linearly (i.e., by translation) from the first position to the second position.

[0186] Of course, without prejudice to the principle of the invention, the construction details and the embodiments may vary widely with respect to those described and illustrated purely by way of example, without departing from the scope of the present invention.

Claims

1. A monitoring system (500) for an on / off type actuator device (1) for activating a valve for a fluid conduit, The actuator device (1) is configured to move a valve member of the valve between a first position corresponding to a normal operating state of the valve and a second position corresponding to an emergency operating state of the valve, the actuator device (1) comprising at least one fluid cylinder (6) configured to drive a linear movement of an actuator rod (8), The monitoring system (500) comprises a plurality of sensors mounted on the actuator device (1) and configured to detect a plurality of operating parameters of the actuator device (1), in, The plurality of sensors include: - at least one pressure sensor (60) for detecting the pressure in the fluid cylinder (6), - a temperature sensor (61) for detecting the temperature in the fluid cylinder (6), - a linear position sensor (62) for detecting the linear position of the actuator rod (8), and - one or more deformation sensors of one or more components of the actuator device (1), And wherein the monitoring system (500) comprises an electronic processing and control unit (50), and the electronic processing and control unit (50) is configured to: - activating the actuator device (1) to cause a micro-movement of the valve member, - during said micro-movement of said valve member, detecting by said plurality of sensors signals indicative of the value of said operating parameter, and - estimating, based on the value of the operating parameter detected during the micro-movement of the valve member, whether the actuator device (1) is able to apply a torque value or a force value sufficient for the valve member to perform a full movement from the first position to the second position, wherein the estimating comprises: - calculating the value of the applicable torque or force that the actuator device (1) can apply to the valve member if the actuator device is controlled to cause the valve member to perform a complete movement from the first position to the second position, - calculating the resisting torque or force required for the actual movement of the valve member from the first position to the second position, - comparing the applicable torque value or force value with a minimum reference value, and / or, comparing the resisting torque value or force value with a maximum reference value, - if the value of the applicable torque or force is lower than the minimum reference value, generating a signal indicating an abnormality of the actuator device (1), and - if the resisting torque value or force value is higher than the maximum reference value, generating a signal indicating an abnormality of the valve, The micro-movement is such that the initiation of the movement of the valve member constituting the valve corresponds only to overcoming mechanical clearances and dissipation and deformation effects inside the actuator device (1) and furthermore does not involve any modification of the fluid flow controlled by the valve, and The steps of detecting the sensor signal and calculating the torque value or force value that can be applied by the actuator device (1) are automatically activated immediately after performing the micro-movement.

2. The monitoring system (500) according to claim 1, wherein: The electronic processing and control unit (50) is further configured to estimate the time required for the valve member to complete a full movement from the first position to the second position based on the value of the operating parameter detected during the micro-movement of the valve member.

3. The monitoring system (500) according to claim 1 or claim 2, wherein: - the actuator device (1) is configured to rotate the valve member of the valve between the first position and the second position, - the actuator device (1) comprises an actuator shaft (5) for driving the valve member to rotate between the first position and the second position and a transmission device (10) for converting the linear movement of the actuator rod (8) into the rotation of the actuator shaft (5), and - the plurality of sensors comprises an angular position sensor (63) for detecting the angular position of the actuator shaft (5).

4. The monitoring system (500) according to claim 1 or claim 2, wherein: The electronic processing and control unit (50) is configured to identify at least one component or subunit of the actuator device (1) which causes the applyable torque value or force value to fall below the minimum reference value due to the applyable torque value or force value falling below the minimum reference value.

5. The monitoring system (500) according to claim 1 or claim 2, wherein: - an electropneumatic control unit (54) is associated with said actuator device (1), and The electronic processing and control unit (50) is configured to identify at least one component or subunit of the electro-pneumatic control unit (54) which causes the applyable torque value or force value to fall below the minimum reference value due to the applyable torque value or force value falling below the minimum reference value.

6. The monitoring system (500) according to claim 1 or claim 2, wherein: - the normal operating state of the valve corresponds to an open state of the valve, and the emergency operating state of the valve corresponds to a closed state of the valve, - the at least one fluid cylinder (6) is a single-acting fluid cylinder, which is usually used to hold the valve member in its first position, - the actuator device (1) further comprises at least one spring (18) coupled to the actuator rod (8') and tending to rotate the valve member towards its second position so that closing of the valve in an emergency situation is achieved by deactivating the fluid cylinder (6), and - the plurality of sensors comprises at least one of a temperature sensor (65) for detecting the temperature at the spring (18) and a load cell sensor (66) for detecting the force exerted by the spring (18) on the actuator rod (8').

7. The monitoring system (500) according to claim 1 or claim 2, wherein: The at least one fluid cylinder (6) is a double-acting cylinder which is activatable in a direction to move the valve member towards the first position and in an opposite direction to move the valve member towards the second position.

8. The monitoring system (500) according to claim 1 or claim 2, wherein: The at least one fluid cylinder (6) comprises a first single-acting cylinder activatable to move the valve member towards the first position and a second single-acting cylinder activatable to move the valve member towards the second position.

9. The monitoring system (500) according to claim 1 or claim 2, comprising an interface panel (52), the interface panel (52) being mounted on the actuator device (1) and configured to: - transmitting the detected value of said operating parameter, - providing a command for activating the actuator device (1) to cause a micro-movement of the valve member, and - transmitting a warning message in case the actuator device (1) is unable to apply to the valve member the torque value or force value sufficient for the valve member to perform a complete movement from the first position to the second position.

10. The monitoring system (500) according to claim 1 or claim 2, comprising a remote interface panel (52), which is connected to the actuator device (1) through a wired or wireless communication line and is configured to: - transmitting the detected value of said operating parameter, - providing a command for activating the actuator device (1) to cause a micro-movement of the valve member, and - transmitting a warning message in case the actuator device (1) is unable to apply to the valve member the torque value or force value sufficient for the valve member to perform a complete movement from the first position to the second position.

11. The monitoring system (500) according to claim 1 or claim 2, wherein: The electronic processing and control unit (50) is mounted on the actuator device (1).

12. The monitoring system (500) according to claim 1 or claim 2, wherein: - the electronic processing and control unit (50) is located in a remote control station (56) and is connected to the actuator device (1) via a wired or wireless communication link, - a sensor of the plurality of sensors mounted on the actuator device (1) transmits a signal indicative of the value of the operating parameter of the actuator device (1) to the electronic processing and control unit (50), and - said electronic processing and control unit (50) transmits a command signal to said actuator device (1) in order to activate it.

13. The monitoring system (500) according to claim 12, wherein: The electronic processing and control unit (50) is connected to a plurality of on / off type actuator devices for activating corresponding valves for fluid conduits and is configured to: - activating the actuator means to produce a micro-movement of the corresponding valve member, - detecting, via a respective plurality of sensors, respective signals indicative of the value of said operating parameter during micro-movements of respective valve members, and - estimating, based on the respective value of the operating parameter detected during the micro-movement of the respective valve member, whether the actuator device is able to apply a respective torque value or force value sufficient for the respective valve member to complete the entire movement from the first position to the second position, wherein the estimating comprises: - calculating the value of the applicable torque or force that the actuator device (1) can apply to the valve member if the actuator device is controlled to cause the valve member to perform a complete movement from the first position to the second position, - calculating the resisting torque or force required for the actual movement of the valve member from the first position to the second position, - comparing the applicable torque value or force value with a minimum reference value, and / or, comparing the resisting torque value or force value with a maximum reference value, - if the value of the applicable torque or force is lower than the minimum reference value, generating a signal indicating an abnormality of the actuator device (1), and - If said resisting torque value or force value is higher than said maximum reference value, a signal is generated indicating an abnormality of said valve.

14. An on / off type actuator device (1) for activating a valve for a fluid conduit, comprising a monitoring system (500) according to any one of claims 1 to 11, The actuator device (1) is configured to move a valve member of the valve between a first position corresponding to a normal operating state of the valve and a second position corresponding to an emergency operating state of the valve, The actuator device (1) comprises at least one fluid cylinder (6) and a plurality of sensors, wherein the fluid cylinder (6) is configured to control the linear movement of an actuator rod (8), wherein the plurality of sensors are configured to detect a plurality of operating parameters of the actuator device (1), and the electronic processing and control unit (50) is mounted on the actuator device (1).

15. A method for monitoring the health status of an on / off type actuator device (1) during operation by means of a monitoring system according to any one of claims 1 to 13, the on / off type actuator device (1) being used to activate a valve for a fluid conduit, the method comprising: - activating the actuator device (1) to cause a micro-movement of the valve member, - during said micro-movement of said valve member, detecting by said plurality of sensors signals indicative of the value of said operating parameter, and - estimating, based on the value of the operating parameter detected during the micro-movement of the valve member, whether the actuator device (1) is able to apply a torque value or a force value sufficient for the valve member to perform a full movement from the first position to the second position, wherein the estimating comprises: - calculating the value of the applicable torque or force that the actuator device (1) can apply to the valve member if the actuator device is controlled to cause the valve member to perform a complete movement from the first position to the second position, - calculating the resisting torque or force required for the actual movement of the valve member from the first position to the second position, - comparing the applicable torque value or force value with a minimum reference value, and / or, comparing the resisting torque value or force value with a maximum reference value, - if the value of the applicable torque or force is lower than the minimum reference value, generating a signal indicating an abnormality of the actuator device (1), and - if the resisting torque value or force value is higher than the maximum reference value, generating a signal indicating an abnormality of the valve, wherein the micro-movement is such that the initiation of the movement of the valve member constituting the valve corresponds only to overcoming mechanical clearances and dissipation and deformation effects inside the actuator device (1) and furthermore is such that no change in the fluid flow controlled by the valve is involved, and The steps of detecting the sensor signal and calculating the torque value or force value that can be applied by the actuator device (1) are automatically activated immediately after the micro-movement is performed.

Images