Shut-off valve for a cooling / heating plant

Abstract

A shut-off valve (1) for a cooling / heating plant (100) is disclosed comprising: - a primary circuit (102) in which a coolant fluid is flowable in use; - a secondary circuit (104) in which in use an operating fluid is flowable which is intended for an utility; - a heat exchanger (105) suitable for transferring thermal energy from the coolant fluif to the operating fluid. The shut-off valve (1) is arranged along the secondary circuit (104) and has the function of interrupting the fluid circulation in the secondary circuit (104). The shut-off valve (1) comprises: - a valve body (2) in which are obtained: - an inlet (3) for the operating fluid; - an outlet (4) for the operating fluid; and - an inner passage (5) suitable for placing the inlet (3) in flowing communication with the outlet (4); - a shutter device (6) interacting with an inner valve seat (7) of the valve body (2) to close the inner passage (5) so as to prevent the transit of fluid in the valve body (2) between the inlet (3) and the outlet (4). The shut-off valve (1) further comprises a sensor device (14) that is sensitive to pressure of said coolant fluid to slide the shutter device (6) along an axis (L) from an open position (PA), in which the shutter device (6) leaves the inner passage (5) free, to a closed position (PC) in which the shutter device (6) closes the inner passage (5) when the pressure value of the fluid that circulates in the secondary circuit (104) exceeds a set pressure value. In this manner, the shut-off valve (1) interrupts the fluid circulation and thus prevents the coolant fluid circulating in the secondary circuit (104) and being able to reach the utility. The set pressure value is a function of the elastic force of a calibrating elastic element of sensor device (14) so as to make the shut-off valve (1) versatile.

Description

SHUT-OFF VALVE FOR A COOLING / HEATING PLANTBackground of the invention

[0001] The present invention relates to a shut-off valve for cooling / heating plants in particular of medium or large dimensions, i.e. intended to be installed in buildings comprising a plurality of utilities or units to be cooled / heated, for example blocks of flats or skyscrapers.

[0002] The invention further relates to a cooling / heating plant comprising a shut-off valve according to the invention.Prior art

[0003] Cooling / heating plants are known comprising a primary circuit in which a coolant fluid is flowable, for example a gas like propane, a secondary circuit in which an operating fluid is flowable, like water, intended to reach thermal transfer terminals for one or more utilities, and a heat exchanger arranged between the primary circuit and the secondary circuit and configured to transfer thermal energy from the coolant fluid to the operating fluid intended to reach one or more utilities located, for example, in an environment like a domestic environment.

[0004] In use, the heat exchanger separates the primary circuit from the secondary circuit such that the coolant fluid cannot reach the secondary circuit.

[0005] Nevertheless, it is possible that the heat exchanger may get damaged or break, for example explode, with the result that the primary circuit and the secondary circuit are placed in flowing communication, which can result in damage to both circuits and, above all, to one or more utilities and to the health of users who may come into contact with the coolant fluid.

[0006] In fact, damage to, or breakage of the heat exchanger causes the coolant fluid to circulate in the secondary circuit in the form of gas, for example propane, owing to the expansion to which the coolant fluid is subjected in the heat exchanger. Generally, the coolant fluids in gaseous state are hazardous for human beings and entail risks of flammability and explosion.

[0007] The coolant fluid present in the primary circuit has pressure values within a range of 5 bar to 50 bar, depending on the type of coolant fluid, whereas the operating fluid present in the secondary circuit has pressure values within a range of 1.5 bar to 6 bar.

[0008] The circulation of coolant fluid in the secondary circuit, owing to damage to or breakage of the heat exchanger, leads to a sudden pressure increase inside the secondarycircuit, which is generally set at a much lower pressure (1,5-6 bar) than that of the coolant fluid.

[0009] Cooling / heating plants of known type comprise one or more safety devices generally set at 3 bar that are tripped in the event of faults. For example, these safety devices comprise a safety valve and an air relief valve.

[0010] One drawback of such safety devices is that in the event of a burst of the walls of the heat exchanger they are unable to completely expel the coolant fluid in gaseous state into the external ambient in a short time but part thereof can circulate in the cooling / heating plant and reach one or more utilities in a quantity that can be harmful to the components of the secondary circuit and to human beings. This occurs in particular in cooling / heating plants of medium and large dimensions in which the quantity of coolant fluid and the pressure thereof are much greater than that of the cooling / heating plants intended for individual residential units.Objects of the invention

[0011] One object of the present invention is to overcome the drawbacks of the aforementioned known safety devices.

[0012] Another object of the present invention is to provide a versatile shut-off valve.

[0013] A further object of the present invention is to provide a shut-off valve that is structurally simple and easily installable which also operates in the absence of electric current.Short description of the invention

[0014] The objects listed above are achieved by a shut-off valve according to the first claim and with a cooling / heating plant according to claim 17.Short description of the drawings

[0015] The invention can be better understood by referring to the attached drawings that illustrate a non-limiting exemplary embodiment thereof in which:Fig. 1 is a schematic view of a cooling / heating plant according to the invention comprising a shut-off valve according to the invention;Fig. 2 is a perspective view of the shut-off valve according to the invention;Fig. 3 is a frontal view of the shut-off valve of Fig. 2;Fig. 4 is a vertical section view according to plane IV-IV of Fig. 3 of the shut-off valve of Fig. 2 in an operating situation showing the vectors associated with the hydraulic forcesacting on internal components of the shut-off valve according to the invention;Fig. 5 is a top view of the shut-off valve of Fig. 2;Fig. 6 is a perspective view of the shut-off valve of Fig. 2 where some elements have been removed;Fig. 7 is a vertical section view according to plane VII- VII of Fig. 5 of the shut-off valve of Fig. 2 in an open configuration;Fig. 8 is an enlarged view of a detail A of Fig. 7;Fig. 9 is an enlarged view of a detail B of Fig. 6;Fig. 10 is a perspective view with a partial section of the shut-off valve of Fig. 2 where some elements have been removed;Fig. 11 is a lateral view of the shut-off valve of Fig. 2 in a closed configuration;Fig. 12 is a vertical section view according to the plane XII-XII of Fig. 11 of the shut-off valve of Fig. 2 in closed configuration;Fig. 13 is an enlarged detail C of Fig. 12;Fig. 14 is a perspective view of the shut-off valve of Fig.2 in closed configuration where some elements have been removed;Fig. 15 is an enlarged view of a detail D of Fig. 14;Fig. 16 is a perspective view of the shut-off valve of Fig.2 in closed configuration where some elements have been removed;Fig. 17 is an enlarged view of a detail E of Fig.10;Fig. 18 is an enlarged view of a detail H of Fig.16.Detailed description of the invention

[0016] With reference to Figure 1, a cooling / heating plant according to the invention configured to cool / heat an environment 101, like for example, a domestic environment, has been indicated overall with 100.

[0017] The cooling / heating plant 100 is in particular a plant of medium or large dimensions, i.e. is intended to be installed in a building comprising a plurality of utilities, environments or units to be cooled / heated, for example blocks of flats or skyscrapers.

[0018] The cooling / heating plant 100 comprises a primary circuit 102, shown schematically in Figure 1, in which a coolant fluid like for example propane is flowable in use. The primary circuit 102 comprises various components of which in Figure 1 only a compressor 103 is illustrated that enables the coolant fluid to flow inside the primary circuit102.

[0019] The cooling / heating plant 100 further comprises a secondary circuit 104, shown schematically in Figure 1, in which in use an operating fluid is flowable, like for example water arranged for cooling / heating an environment like the environment 101, for example, a domestic environment. The operating fluid is intended, in particular, to reach one or more thermal transfer terminals for one or more utilities provided in the environment 101.

[0020] The cooling / heating plant 100 further comprises a heat exchanger 105, shown schematically in Figure 1, configured to transfer thermal energy from the coolant fluid to the operating fluid.

[0021] The heat exchanger 105 is interposed between the primary circuit 102 and the secondary circuit 104 and separates the primary circuit 102 from the secondary circuit 104 such that the coolant fluid, in conditions of correct operation of the heat exchanger 105, cannot reach the secondary circuit 104 and thus one or more utilities. In other words, the primary circuit 102 and the secondary circuit 104 are not in flowing connection in conditions of correct operation of the heat exchanger 105, because the coolant fluid, if it circulates in the secondary circuit 104, can damage the secondary circuit 104 because of the high pressure at which the coolant fluid would be delivered to the secondary circuit 104 and can be harmful to the health of human beings because it is toxic to human beings if it reaches the environment 101 in which human beings may be present.

[0022] The cooling / heating plant 100 further comprises a shut-off valve 1 which is arranged along the secondary circuit 104 and has the function of interrupting fluid circulation, in particular of coolant fluid, in the secondary circuit 104, in the event of breakage (for example explosion) or damage to the heat exchanger 105 connected to the secondary circuit 104 and in which the coolant fluid circulates that must not reach the one or more utilities that the cooling / heating plant 100 has to cool / heat.

[0023] In the following description, the expressions “downwards” and “upwards” and the terms “upper” (with reference to a spatial arrangement) “above” and “below” refer to the arrangement of the elements of the shut-off valve 1 in the Figures appended here that can differ from how the shut-off valve 1 is fitted in the cooling / heating plant 104.

[0024] The shut-off valve 1 is in particular arranged on a delivery branch 106 of the secondary circuit 104 in which in use, a flow of operating fluid flows along a flowing direction S. When the heat exchanger 105 operates correctly, the fluid flowing in thesecondary circuit 104 is only operating fluid. When on the other hand the heat exchanger 105 does not operate correctly, for example explodes, the coolant fluid is added to the operating fluid in a portion of the secondary circuit 104. In particular, in this case, the coolant fluid circulates in the secondary circuit 104 substantially in a portion comprised between the heat exchanger 105 and the shut-off valve 1 inasmuch as the latter, as soon as it intercepts the presence of coolant fluid, intervenes to close the fluid circulation in the secondary circuit 104. The presence of coolant fluid in the secondary circuit 104 is detected by the shut-off valve 1 through the high pressure associated with the coolant fluid with respect to the pressure of the operating fluid.

[0025] The shut-off valve 1 comprises a valve body 2 in which at least one inlet 3 for the operating fluid and at least one outlet 4 for the operating fluid are obtained.

[0026] The shut-off valve 1 further comprises an inner passage 5 suitable for placing the inlet 3 in flowing communication with the outlet 4. In this manner, the shut-off valve 1 can be traversed, in use, by the operating fluid. In particular, in use the shut-off valve 1 is traversed by the operating fluid when the heat exchanger 105 operates correctly.

[0027] The inlet 3 of the shut-off valve 1 is installed in the secondary circuit 104 so as to be in flowing communication with the heat exchanger 105 whereas the outlet 4 is installed in the secondary circuit 104 so as to be in flowing communication with thermal transfer terminals 109, for example radiators, schematically illustrated in Figure 1.

[0028] The secondary circuit 104 of the cooling / heating plant 100 further comprises a return branch 107 on which the operating fluid is intended to circulate to return to the heat exchanger 105.

[0029] The cooling / heating plant 100 further comprises a retaining device 108, installed on the return branch 107, arranged to enable the flow of operating fluid to flow only in the flowing direction S and prevent the transit of fluid in a direction opposite the direction of the flowing direction S.

[0030] The retaining device 108 comprises a check valve or a further shut-off valve 1. In the latter case, the further shut-off valve 1 is so installed that the inlet 3 is in flowing communication with the thermal transfer terminals 109 whereas the outlet 4 is in flowing communication with the heat exchanger 105.

[0031] The shut-off valve 1 further comprises a shutter device 6 arranged for interacting with an inner valve seat 7 of the valve body 2 to close the inner passage 5 so as to preventthe transit of fluid in the valve body 2 between the inlet 3 and the outlet 4.

[0032] In use, the shutter device 6 is slidingly movable along an axis L, for example a longitudinal axis, between an open position PA (Figure 7) in which the shutter device 6 leaves the inner passage 5 free and thus permits the transit of a flow of operating fluid, and a closed position PC (Figure 12) in which the shutter device 6 closes the inner passage 5 and thus prevents fluid circulation between the inlet 3 and the outlet 4 of the shut-off valve 1.

[0033] The shut-off valve 1 further comprises retaining means 40 arranged for retaining the shutter device 6 axially in the open position PA.

[0034] The shutter device 6 comprises a shank 8, arranged in particular coaxially with the axis L, from an end of which an annular element 9 protrudes that, in the closed position PC, is intended to abut on an upper edge 10 of a protruding element 11 of the valve seat 7 to close the inner passage 5 hermetically and accordingly prevent a flow of (heat-conducting and / or operating) fluid into the secondary circuit 104.

[0035] The protruding element 11 has, in particular, a substantially annular shape and the upper edge 10 has, in particular, a substantially circular crown shape.

[0036] The shank 8 and the annular element 9 are made in particular as a single body.

[0037] The annular element 9 is provided with a first face 48 arranged at the valve seat7 and with a second face 49 arranged opposite the first face 48. The first face 48 and the second face 49 are suitable for containing a seal.

[0038] The upper edge 10, when the shutter device 6 is in the closed position PC, defines a seal surface for fluids. This seal surface is made with a dimension that is as small as possible in order to influence as little as possible the balance of the hydraulic forces acting on the shutter device 6, as will be explained better further on in the description.

[0039] The shut-off valve 1 further comprises an elastic thrust element 12, like a coil spring, that, in use, reacts on a protrusion 13 of the shutter device 6 in a closing direction Y1 of the shutter device 6 to contribute to taking the latter to the closed position PC. When the shutter device 6 is in the open position PA, the elastic thrust element 12 is in a contracted configuration, whilst in the closed position PC the elastic thrust element 12 is in an elongated configuration.

[0040] With reference to Figure 12, the closing direction Y1 points, in particular, downwards, whereas with reference to Figure 7, an open direction Y2, along which the shutter device 6 is moved to reach the open position PA starting from the closed positionPC, points, in particular, upwards, i.e. the closing direction Y1 and the open direction Y2 have an opposite direction.

[0041] The closing direction Y 1 and the open direction Y2 are in particular substantially vertical and parallel to the axis L.

[0042] The shut-off valve 1 further comprises a sensor device 14 sensitive to pressure of the fluid that circulates in the secondary circuit 104 and is configured to slide the shutter device 6 along the axis L from the open position PA to the closed position PC when the pressure value of the fluid exceeds a set pressure value.

[0043] The sensor device 14 comprises a release device 15 arranged for releasing the shutter device 6 from the retaining means 40.

[0044] The release device 15 comprises a cylinder element 16 and a piston element 17 sealingly slidable along the axis L inside a chamber 26 of the cylinder element 16. The piston element 17 is provided with a thrust surface 18 in communication with the fluid circulating in the secondary circuit 104, i.e. with the operating fluid, in conditions of correct operation of the heat exchanger 105, or with the operating fluid and the coolant fluid, if the heat exchanger 105 malfunctions or is broken.

[0045] This fluid (operating fluid or operating fluid with coolant fluid), exerts, in use, pressure on the thrust surface 18.

[0046] The piston element 17 in use is movable between a retracted position T (Figure 7) in which the thrust surface 18 is near an upper internal surface 30 of the cylinder element 16 and an advanced position V (Figure 12) in which the thrust surface 18 is at a distance from the upper internal surface 30 of the cylinder element 16 and nearer the shutter device 6 than the retracted position T.

[0047] The sensor device 14 further comprises a calibrating elastic element 19, like a coil spring, which is received inside the chamber 26 of the cylinder element 16.

[0048] The hydraulic seal of the piston element 17 inside the chamber 26 is permitted by at least one seal element 57, like, for example, an O-ring. The seal element 57 is positioned interposed between a side surface 67 of the piston element 17 and a side surface 68 of the cylinder element 16 to prevent the fluid (coolant fluid and / or operating fluid) being able to move from a first portion 29 of the chamber 26 on which the thrust surface 18 faces to a second portion 59 of the chamber 26 where the calibrating elastic element 19 is received. The first portion 29 and the second portion 59 are separate from the piston device 17.

[0049] In the embodiment of shut-off valve 1 illustrated in the Figures, there are two seal elements 57.

[0050] The calibrating elastic element 19 can be connected at one end to the piston element 17 and at another end to the cylinder element 16 to constantly urge the thrust surface 18 to the upper internal surface 30 of the cylinder element 16.

[0051] The calibrating elastic element 19, in fact, in use, acts on a ring 20 fitted to the piston element 17 and reacts on a bottom 21 of the cylinder element 16 so as to maintain the thrust surface 18 near the upper internal surface 30 of the cylinder element 16, when pressure does not exceed the set pressure value.

[0052] The set pressure value is a function of the elastic force associated with the calibrating elastic element 19. When, in fact, the elastic force of the calibrating elastic element 19 is less than the force acting orthogonally to the thrust surface 18 and exerted by the fluid (coolant fluid and / or operating fluid), then the shutter device 6 is released by the retaining means 40 by means of the release device 15 and taken to the closed position PC with the help of the elastic thrust element 12.

[0053] Vice versa, when the elastic force of the calibrating elastic element 19 is greater than the force acting orthogonally to the thrust surface 18 and exerted by the fluid (that in this case is only the operating fluid), then the shutter device 6 is retained by the retaining means 40 in the open position PA.

[0054] In other words, the intervention calibrating pressure of the shut-off valve 1 is regulated by the elastic force of the calibrating elastic element 19.

[0055] The shut-off valve 1 is thus configured to be driven between an open configuration M (Figure 7) in which it allows fluid circulation between the inlet 3 and the outlet 4 of the valve body 2 and a closed configuration N (Figure 12) in which it prevents fluid circulation between the inlet 3 and the outlet 4 of the valve body 2. The shut-off valve 1 is driven from the open configuration M to the closed configuration N when the sensor device 14 detects a pressure value of the fluid that circulates in the secondary circuit 104 above the set pressure value so as to prevent the coolant fluid, that has possibly entered the secondary circuit 104, from reaching the environment 101.

[0056] The thrust surface 18 receives the pressure of the flow of fluid circulating in the secondary circuit 104 by a capillary pipe 22 connected at a first end 23 to the chamber 26 and at a second end 24 to a pick up zone 58 of the secondary circuit 104 from which a portionof flow of fluid circulating in the secondary circuit 104 is tapped.

[0057] In particular, the first end 23 of the capillary pipe 22 is fitted hermetically to the valve body 2 at an upper end 25 of an inlet conduit 27 obtained in the valve body 2. The inlet conduit 27 is in flowing communication via an inlet opening 28 with the first portion 29 of the chamber 26 defined between the thrust surface 18 and the upper internal surface 30 of the cylinder element 16 into which first portion 29 the fluid picked up from the pick up zone 58 flows.

[0058] The pick up zone 58 can be provided in the shut-off valve 1, in particular in the first portion 29 of the chamber 26. In particular, the second end 24 can be hermetically fitted to the valve body 2 at an open end 31 of a pick up conduit 32 flowing, via a pick up opening 33, into the inner passage 5. In this case the pick up zone 58 is thus provided in the inner passage 5.

[0059] Alternatively, the pick up zone 58 can be provided upstream of the shut-off valve 1 with respect to the flowing direction S of the flow of fluid in the secondary circuit 104. In particular, the second end 24 can be fitted hermetically to the delivery branch 106 of the secondary circuit 104 so as to be in flowing communication with the delivery branch 106 via an opening made in the secondary circuit 104.

[0060] Owing to the capillary pipe 22, in use, flow of fluid circulating in the secondary circuit 104 is taken from the secondary circuit 104, passes through the capillary pipe 22 and then flows inside the first portion 29 of the chamber 26 of the cylinder element 16. In the first portion 29 of the chamber 26, the flow of fluid exerts pressure on the thrust surface 18. The pressure of the fluid on the thrust surface 18 is substantially equivalent to the pressure of the fluid in the secondary circuit 104. By the capillary pipe 22, following a sudden pressure variation in the secondary circuit 104, the flow of fluid exerts thrust pressure on the thrust surface 18 that causes an axial shift of the piston element 17 along the axis L along the closing direction Yl.

[0061] The release device 15 further comprises a release tip 34 connected stiffly to the piston element 17 to be movable integrally with the latter. In particular, the release tip 34 and the piston element 17, in use, are integrally slidable along the axis L inside the cylinder element 16.

[0062] Accordingly, when the piston element 17 is moved from the retracted position T to the advanced position V also the release tip 34 is moved accordingly (along the closingdirection Yl) and approaches the shutter device 6.

[0063] The release tip 34 is configured to interact with the retaining means 40 in order to release the shutter device 6 from the retaining means 40 such that the shutter device 6 can be taken to the closed position PC.

[0064] The release tip 34 can extend with a substantially longitudinal prevalent direction of extent. The release tip 34 can be arranged substantially coaxial with the axis L. The calibrating elastic element 19 is in particular wound around the release tip 34.

[0065] The ring 20 is so made as to surround a portion of the release tip 34.

[0066] The release tip 34 is fitted, for example screwed, in a cavity 35 that is for example threaded, obtained in the piston element 17. The cavity 35 faces, in particular, the second portion 59 of the chamber 26 on a side opposite the first portion 29. The release tip 34 is sized so as to protrude downwards outside the cylinder element 16.

[0067] The release tip 34 is provided with a stem 36 provided at one end with a tip 37 suitable for causing the shutter device 6 to disengage from the retaining means 40.

[0068] The tip 37 is tapered and has, in particular, a substantially conical or frustoconical shape.

[0069] The retaining means 40 comprises a hollow bush 41 fitted to the valve body 2.

[0070] The elastic thrust element 12 is wound, at least partially, around a portion of a release rod 50 and to a portion of the shank 8 of the shutter device 6.

[0071] The elastic thrust element 12 is connected at one end to an annular abutting element 39 fitted to said bush 41 and at another end to a protrusion 13 of said shutter device 6.

[0072] The elastic thrust element 12 in use acts on the annular abutting element 39 and reacts on the protrusion 13 of the shutter device 6 so as to promote an axial shift of the shutter device 6 along the closing direction Yl, when the pressure exceeds the set pressure value.

[0073] The bush 41 is so fitted that a hollow central portion 42 thereof is substantially coaxial with the axis L.

[0074] The central portion 42 has a substantially hollow cylindrical shape.

[0075] With reference in particular to Figures 8, 13, 17 and 18, in the central portion 42 at least two retaining seats 43 are obtained each configured to receive, at least partially, a respective retaining element 44 with which the retaining means 40 can be provided. The retaining seats 43 are, in particular, opposite, i.e. arranged opposite with respect to the axisL.

[0076] Each retaining seat 43 is provided with a window 45 that faces the hollow inside of the central portion 42 through which the retaining elements 44 can interact with the tip 37. The release tip 34 is in fact so configured that when the shut-off valve 1 is in the open configuration M, a side surface of the tip 37 thereof rests on the retaining elements 44 through the windows 45 or is in a retracted position with respect to the retaining elements 44.

[0077] Each retaining seat 43 can be obtained by removing material, for example by a milling operation, from the central portion 42. In other words, each retaining seat 43 is a sort of slit or milling obtained in the thickness of the central portion 42. Each retaining seat 43 is defined, in particular, by surfaces obtained in a thickness of the central portion 42. Each retaining seat 43 comprises in particular, a sliding surface 54 on which, in use, the retaining elements 44 roll when the shutter device 6 is moved between the open position PA and the closed position PC.

[0078] The retaining elements 44 are connected by at least one, in particular two, elastic retaining elements 46 that retain the retaining elements 44 elastically in the retaining seats 43.

[0079] The windows 45 enable the retaining elements 44 to interact with a side surface of the tip 37.

[0080] Each retaining element 44 comprises a revolving element, for example di substantially cylindrical shape. For example, each retaining element 44 can be, or is provided with, a roller.

[0081] Each retaining element 44 extends, in particular, along a direction of extent that is substantially transverse to the axis L.

[0082] Each elastic retaining element 46 comprises a torsion spring, provided with two end shanks 47, an end shank 47 being fitted so as to be wound around a retaining element 44 whereas the other end shank 47 is fitted so as to be wound around a second retaining element 44. In this manner, the elastic retaining elements 46 retain the retaining elements 44 elastically which, in turn, by interacting with the tip 37, support the release tip 34 in conditions of fluid pressure in which the shutter device 6 is in the open position PA, i.e. when the value of the elastic force associated with the pressure acting on the thrust surface 18 is less than the elastic force of the calibrating elastic element 19.

[0083] The shut-off valve 1 further comprises the release rod 50 fitted substantially coaxially to the axis L and connected to the shutter device 6, in particular stiffly, to cause an axial shift thereof.

[0084] The retaining means 40 is arranged for interacting with the release rod 50 to retain axially the shutter device 6 in the open position PA.

[0085] The release rod 50 comprises a connecting portion 51 connected to the shank 8 so as to connect the release rod 50 to the shutter device 6 stiffly. In this manner, in use, the release rod 50 and the shutter device 6 are movable integrally.

[0086] The release rod 50 further comprises a cylindrical portion 52 fitted to the connecting portion 51. The cylindrical portion 52 is hollow so as to receive at least partially the release tip 34 internally. Further, the cylindrical portion 52 is fitted so as to be interposed between the central portion 42 of the bush 41 and the release tip 34, the central portion 42 thus being arranged at a greater distance from the axis L with respect to the cylindrical portion 52. The cylindrical portion 52 is in particular screwed on the shutter device 6 at an inner threaded portion 38 of the shank 8.

[0087] The cylindrical surface 52 has a diameter indicated with DI in Figures 2 and 8.

[0088] With reference in particular to Figures 8, 13, 17 and 18, in the cylindrical portion52, at least two housings 53 are obtained that are arranged for each receiving, at least partially, a respective retaining element 44, when the shutter device 6 is in the open position PA. The two housings 53 are, in particular, opposite, i.e. arranged opposite with respect to the axis L.

[0089] Each housing 53 is provided with a retaining opening 55 that faces the hollow inside of the cylindrical portion 52 through which the retaining elements 44 can interact with the tip 37. The release tip 34 is in fact so configured that when the shut-off valve 1 is in the open configuration M, a side surface of the tip 37 thereof rests on the retaining elements 44 through the windows 45 and the retaining openings 55.

[0090] The retaining elements 44 are each arranged for engaging a corresponding retaining opening 55 obtained in the cylindrical portion 52 so as to press therebetween the release rod 50 and prevent the latter from being moved along the axis L.

[0091] Each housing 53 can be obtained by removing material, for example by a milling operation, from the cylindrical portion 52. In other words, each housing 53 is a sort of slit or milling obtained in the thickness of the cylindrical portion 52. Each housing 53 is defined inparticular, by surfaces obtained in a thickness of the cylindrical portion 52.

[0092] Each housing 53 comprises, in particular, a rest and sliding surface 56 on which, in use, the retaining elements 44 rest when the shutter device 6 is in the open position PA and the retaining elements 44 roll when the shutter device 6 is moved between the open position PA and the closed position PC.

[0093] The retaining elements 44, when inserted into the housings 53 and retained by the elastic retaining elements 46, have the function of retaining axially the release rod 50 and thus the shutter device 6. In fact, the retaining elements 44, when the pressure is below the set pressure value, occupy the retaining openings 55, preventing the release rod 50 from moving along the closing direction Yl. When the release rod 50 is retained by the retaining elements 44, the shut-off valve 1 is in the open configuration M and the shutter device 6 is thus in the open position PA.

[0094] Each elastic retaining element 46 is drivable between a near, or retained, position R in which the elastic retaining elements 46 retain the retaining elements 44 in the housings 53 (in particular in the retaining openings 55) and a spaced, or released, position G in which the end shanks 47 are at a further distance from the axis L with respect to the near position R and the elastic retaining elements 46 retain the retaining elements 44 only in the retaining seats 43 and no longer in the housings 53. In fact, when the elastic retaining elements 46 move from the near or retained position R to the spaced or released position, G, the retaining elements 44 roll away from the axis L and exit the retaining openings 55 releasing the release rod 50 from the retaining means 40.

[0095] When the shut-off valve 1 is in the open configuration M, the elastic retaining elements 46 are in the near position R, whilst when the shut-off valve 1 is in the closed configuration N the elastic retaining elements 46 are in the distanced position G.

[0096] In use, the window 45 of each retaining seat 43 is arranged alongside a respective retaining opening 55 of a housing 53. In this manner, each retaining element 44 can be received at least partially in a retaining seat 43 and in the housing 53 that is placed alongside each retaining element 44. Through the windows 45 and the retaining openings 55 the retaining elements 44 can interact with the tip 37; the shut-off valve 1 is in the open configuration M and the shutter device 6 is in the open position PA. When, on the other hand, the pressure on the thrust surface 18 exceeds a set pressure value, the piston element 17 is moved axially along the closing direction Yl by the force acting on the thrust surface18 that exceeds the elastic force of the calibrating elastic element 19. Moving the piston element 17 entails moving the release tip 34. The side surface of the tip 37 presses against the retaining elements 44 and makes the retaining elements 44 move from the respective housings 53 towards the retaining seats 43 along a respective direction of distancing from the axis L. In this manner, the release rod 50 is no longer retained by the retaining elements 44 and slides along the closing direction Yl, taking the shutter device 6 to the closed position PC.

[0097] Further, the sliding surface 54 of a retaining seat 43 and the rest and sliding surface 56 of a housing 53 placed alongside the retaining seat 43 when the shutter device 6 is in the open position PA can be arranged so as to belong, substantially, to the same plane. This facilitates rolling of the retaining elements 44 between the two surfaces.

[0098] Rolling of the retaining elements 44 between the sliding surface 54 of a retaining seat 43 and the rest and sliding surface 56 of a housing 53 fitted alongside this retaining seat 43 occurs along the direction of distancing from the axis L when the shut-off valve 1 moves from the open configuration M to the closed configuration N whereas it occurs along a direction of approach to the axis L when the shut-off valve 1 moves from the closed configuration N to the open configuration M.

[0099] The shut-off valve 1 further comprises a reset rod 60 arranged for taking the shutter device 6 from the closed position PC to the open position PA when the pressure value of the coolant fluid and / or of the operating fluid acting on the thrust surface 18 is lower than the set pressure value. Owing to the reset rod 60, the shut-off valve 1 can be again traversed by the operating fluid.

[0100] The reset rod 60 is fitted slidably to the valve body 2. The reset rod 60 can be fitted substantially coaxially with the axis L.

[0101] The shut-off valve 1 further comprises a hood 61 fitted to the valve body 2 to cover and protect an end 62 of the reset rod 60. The hood 61 can be made, in particular, of plastics. Between the hood 61 and the end 62 of the reset rod 60 a space 66 is defined. A fluid like for example air can be present in the space 66.

[0102] The reset rod 60, in use, can be driven along the open direction Y2, for example, manually by an operator so as to restore the function of the shut-off valve 1.

[0103] The reset rod 60 has a substantially cylindrical shape having a diameter indicated by D2 in Figures 2, 7 and 12.

[0104] The diameter D2 is substantially the same as the diameter DI of the cylindrical portion 52 of the release rod 50. This contributes to balancing the pressure acting on the shutter device 6.

[0105] The shut-off valve 1 further comprises a connecting rod 70 arranged for connecting the shutter device 6 to the reset rod 60 such that, in use, the shutter device 6 and the reset rod 60 are integrally movable.

[0106] The connecting rod 70 is fitted, in particular screwed or fitted in a shape-coupled manner, on one side to a further end 63 of the reset rod 60 opposite the end 62 and, on the other side, to an inner portion 64 of the shank 8 of the shutter device 6.

[0107] The shut-off valve 1 further comprises seal means 80 arranged for confining the operating fluid that traverses the shut-off valve 1 in the inner passage 5.

[0108] The seal means 80 comprises a first annular seal 81, for example an O-ring, clearly visible in Figure 17, arranged above in an annular seal seat 82 formed in the bush 41 .

[0109] The seal means 80 further comprises a second annular seal 83, clearly visible for example in Figure 12, for example an O-ring, arranged below in a further annular seal seat 84 obtained in the valve body 2 at the reset rod 60.

[0110] The shutter device 6 is pressure balanced, i.e., the same pressure acts on the surfaces thereof which in use are in contact with the operating fluid that circulates in the secondary circuit 104, both when the shutter device 6 is in the open position PA and when the shutter device 6 is in the closed position PC, so that closing of the shutter device 6 is independent of the pressure of the secondary circuit 104, but dependent only on the pressure acting on the thrust surface 18.

[0111] Balancing the shutter device 6 is achieved owing to the connecting rod 70 which, by connecting the reset rod 60 to the shutter device 6, causes that the same pressure acts both on the first face 48 and on the second face 49 of the shutter device 6 (see in particular Fig. 4 where the hydraulic forces have been illustrated acting in the inner passage 5 on the shutter device 6). In the absence of the connecting rod 70, the corresponding force on the pressure acting on the first face 48 would be greater than that acting on the second face 49.

[0112] Further, the first annular seal 81 and the second annular seal 83 define in the shut-off valve 1 two seal sections, between which the operating fluid is maintained when the shut-off valve 1 is in the open configuration M.

[0113] The two seal sections are made so as to have the same dimensions. In fact, bysizing the release rod 50 and the reset rod 60 so as to have the respective diameters DI and D2 substantially equivalent entails that the same pressure difference acts on the first annular seal 81 and on the second annular seal 83, this contributing to making the shutter device 6 balanced.

[0114] The cooling / heating plant 100 further comprises one or more safety devices fitted upstream of the shut-off valve 1 with respect to the flowing direction S of the flow of operating fluid on the delivery branch 106. For example, such safety devices comprise a safety valve and an air relief valve.

[0115] An example of the operation of the shut-off valve 1 according to the invention will be disclosed below.

[0116] It is supposed in this example that the shut-off valve 1 is installed in the secondary circuit 104 of a cooling / heating plant 100 of medium or large dimensions, in particular on the delivery branch 106 such that the inlet 3 of the shut-off valve 1 is in flowing connection with a heat exchanger 105 so as to receive an operating fluid and the outlet of the shut-off valve 1 is in flowing connection with an utility for heating or cooling an environment 101.

[0117] The operating fluid flows in the flowing direction S to reach the thermal transfer terminals 109 for the one or more utilities provided in the environment 101. The heat exchanger 105, installed upstream of the shut-off valve 1 with respect to the flowing direction S, is suitable for transferring thermal energy from a coolant fluid to the operating fluid that then reaches the inlet 3.

[0118] When the heat exchanger 105 operates correctly, the shut-off valve 1 is in the open configuration M in which the shutter device 6 is in the open position PA and the circulation of a flow of operating fluid to the delivery branch 106 through the shut-off valve 1 is thus allowed. In other words, the flow of operating fluid circulates between the inlet 3 and the outlet 4 through the inner passage 5.

[0119] When the heat exchanger 105 operates correctly, in fact, pressure that is less than the set pressure value acts on the thrust surface 18. In fact, in this case only the pressure of the flow of operating fluid picked up from the pick up zone 58 by the capillary pipe 22 of the sensor device 14 acts on the thrust surface 18.

[0120] The thrust surface 18 is kept near, in particular abutting on, the inner upper surface 30 of the cylinder element 16 owing to the help of the calibrating elastic element 19that pushes the piston element 17 elastically towards the inner upper surface 30. As a result, the piston element 17 is in the retracted position T and the elastic seal elements 46 are in the near position R. Accordingly, the release rod 50 is maintained locked in position by the elastic seal elements 46 that interact elastically with the seal elements 44 acting on the retaining openings 55. The release tip 34 is in a rest position in which the tip 37 rests on, or is near the, seal elements 44. The release rod 50 in turn retains the shutter device 6 in the open position PA.

[0121] The elastic thrust element 12 is contracted and the corresponding stored energy is a function, on the basis of Hooke’s law, of the shortening to which is subjected with respect to the rest position thereof.

[0122] If, on the other hand, the heat exchanger 105 does not operate correctly but suffers damage and, in particular, explodes, in the secondary circuit 104 also the coolant fluid enters into circulation. A flow of high-pressure coolant fluid to which the sensor device 14 is sensitive is thus added to the flow of operating fluid flowing in the flowing direction S.

[0123] The sensor device 14, in fact detects the pressure difference between the pressure of the flow of operating fluid normally circulating in the secondary circuit 104 and the pressure of the flow of fluid comprising coolant fluid and operating fluid and takes the shutoff valve to the closed configuration N.

[0124] The pressure of the flow of fluid comprising both operating flow and heat- conducting flow acts on the thrust surface 18, this fluid being picked up from the pick up zone 58 by the capillary pipe 22 of the sensor device 14. The pressure of the flow of this fluid is greater than the set pressure value because of the presence of the high-pressure coolant fluid.

[0125] When the force acting on the thrust surface 18 exceeds the elastic force of the calibrating elastic element 19, the thrust surface 18 is moved away from the inner upper surface 30 of the cylinder element 16 and the piston element 17 is taken to the advanced position V. Accordingly, the tip 37 of the release tip 34 presses on the seal elements 44 and makes the seal elements 44 roll away from the axis L. When the distance between opposite seal elements 44 exceeds the diameter DI, i.e. the retaining elements 44 exit the housings 53, the release rod 50 is no longer retained by the retaining means 40 and is pushed, together with the shutter device 6, along the closing direction Y1 with the help of the elastic thrustelement 12. The shutter device 6 is then taken to the closed position PC in which the annular element 9 abuts against the edge 10 thus closing the inner passage 5.

[0126] The shut-off valve 1 is thus now in closed configuration N in which the transit of a flow of fluid through the shut-off valve 1 is inhibited.

[0127] The fluid circulation in the secondary circuit 104 is interrupted instantaneously following detection by the sensor device 14 of pressure that is greater than set pressure, so as to prevent the coolant fluid reaching the utility.

[0128] In order to take the shut-off valve 1 from the closed configuration PC to the open configuration PA, once the heat exchanger 105 is repaired or replaced, a user can push upwards in the open direction Y2 the end 62 of the reset rod 60, by acting on the hood 61, if it is present. In this manner, owing to the connecting rod 70, the movement of the reset rod 60 is transferred to the shutter device 6 that can thus move away from the closed position PA. In order to reach the open configuration N in which the shutter device 6 is locked by the retaining means 40 in the open position PA, the user has to push in the open direction Y2 until the tip 37 of the release tip 34 reaches the windows 45 and the retaining openings 55 such that the elastic retaining elements 46 move from the distanced position G to the near position R because of the narrowing of the release tip 34 due to the tip 37. The tapered surface of the tip 37 further facilitates rolling of the retaining elements 44 from the sliding surface 54 of the retaining seat 43 in which when the shut-off valve 1 is in the closed configuration N they are exclusively housed towards the rest and sliding surface 56 of the opening 53 in which they are housed when the shut-off valve 1 is in the closed configuration N to retain axially the release rod 50 by insertion thereof into the retaining openings 55.

[0129] Owing to the sensor device 14 of the shut-off valve 1 according to the invention, when the pressure value of the secondary circuit 104 on which the shut-off valve 1 is arranged rises to the calibrating value of the shut-off valve 1 because of a breakage of the heat exchanger 105, the shut-off valve 1 instantaneously closes, by driving the shutter device 6 by the sensor device 14, the fluid circulation in the secondary circuit 104, in particular on the delivery branch 106. As a result, the coolant fluid circulating in the primary circuit 102 upstream of the heat exchanger 105 cannot circulate in the secondary circuit 104 and reach one or more utilities for which the operating fluid is intended. Accordingly, the shut-off valve 1 according to the invention effectively prevents the circulation of the coolant fluid inside the environment 101 in which the utility is arranged.

[0130] With reference to Figure 4, the vectors of the forces acting along the closing direction Yl, i.e. downwards considering the arrangement of the shut-off valve 1 of the Figures, for example the forces acting on the second face 49 of the annular element 9 of the shutter device 6 are shown with Fl and the vectors of the forces acting along the open direction Y2, i.e. upwards considering the arrangement of the shut-off valve 1 of the Figures, for example the forces acting on the first face 48 of the annular element 9 of the shutter device 6 are shown with F2. As is clear from the Figure, the summation of the hydraulic forces Fl and the summation of the hydraulic forces F2, opposite the hydraulic forces Fl, indicated in Fig. 4, have the same value.

[0131] As the forces Fl and F2 are equal, the shutter device 6 is balanced, i.e. is not affected by the hydraulic forces of the fluid inside the valve body 2. In other words, the equality of the forces Fl and F2 makes the shutter device 6 insensitive to possible pressure surges or differences in the shut-off valve 1.

[0132] This does not only apply when the shut-off valve 1 is in the open configuration M, but also when the shutter device 6 moves between the open position PA and the closed position PC (condition in which the forces Fl and F2 are the same as those acting when the shut-off valve 1 is in the open configuration M) or when the shut-off valve 1 is in the closed configuration N. In the latter case, there can be a slight pressure imbalance due to the upper edge 10, on which hydraulic forces do not act in the closed configuration N unlike when the shutter device 6 is in the open position PA Nevertheless, this upper edge 10 is sized so as to be as small as possible in order to influence as little as possible, or not at all, balance of the shutter device 6.

[0133] The balance of the hydraulic forces acting on the shutter device 6 is particularly advantageous since in this manner the set pressure value beyond which the shut-off valve 1 goes to the closed configuration N is independent of, i.e. is not influenced by, the pressure of the secondary circuit 104, but only by the elastic force of the calibrating elastic element 19. In other words, the set pressure value at which the sensor device 14 trips to close the shut-off valve 1, i.e. the tripping pressure, is a function of only the elastic force of the calibrating elastic element 19.

[0134] As we have seen, the balance of the hydraulic forces acting on the shutter device 6 is made possible owing to the connecting rod 70. In particular, connecting the reset rod 60 to the shutter device 6 by the connecting rod 70 reduces the area on which the forces F2 acton the first face 48 with respect to cases in which the connecting rod 70 is not present and the entire area of the first face 48 is exposed to the hydraulic forces F2. In addition, in order to promote the balance of the hydraulic forces on the shutter device 6, the diameter DI of the release rod 50 and the diameter D2 of the reset rod 60 are substantially the same, so that the same hydraulic forces act on the first annular seal 81 and on the second annular seal 83.

[0135] The shut-off valve 1 is thus very versatile because the same calibrating elastic element 19 can be used (and thus the same shut-off valve 1) for any pressure value of the fluid in the secondary circuit 104 and not a calibrating elastic element 19 for each pressure value of the fluid in the secondary circuit 104.

[0136] Advantageously, the shut-off valve 1 also operates in the absence of electric power.

[0137] Variations on and additions to what has been disclosed and illustrated above can be provided.

[0138] The configuration of the valve body, like the configuration and number of the components disclosed and illustrated can vary.

Claims

CLAIMS1. Shut-off valve (1) for a cooling / heating plant (100), said cooling / heating plant (100) comprising:- a primary circuit (102) in which a coolant fluid is flowable in use;- a secondary circuit (104) in which in use an operating fluid is flowable which is intended for an utility;- a heat exchanger (105) suitable for transferring thermal energy from said coolant fluid to said operating fluid; said shut-off valve (1) being arranged along said secondary circuit (104) to interrupt the fluid circulation in said secondary circuit (104), said shut-off valve (1) comprising:- a valve body (2) in which are obtained:- an inlet (3) for said operating fluid;- an outlet (4) for said operating fluid; and- an inner passage (5) suitable for placing said inlet (3) in flowing communication with said outlet (4);- a shutter device (6) interacting with an inner valve seat (7) of said valve body (2) to close said inner passage (5) so as to prevent the passage of fluid in said valve body (2) between said inlet (3) and said outlet (4); said shut-off valve (1) being characterized in that further comprises a sensor device (14) that is sensitive to pressure of said coolant fluid to slidly drive said shutter device (6) along an axis (L) from an open position (PA) in which said shutter device (6) leaves said inner passage (5) free, to a closed position (PC) in which said shutter device (6) closes said inner passage (5) when the pressure value of the fluid circulating in said secondary circuit (104) and acting on a thrust surface (18) of said sensor device (14) exceeds a set pressure value.

2. Shut-off valve (1) according to claim 1, wherein said sensor device (14) comprises a cylinder element (16), a piston element (17) provided with said thmst surface (18), and a release tip (34) connected stiffly to said piston element (17) to be movable integrally with the latter, said piston element (17) being sealingly slidable along said axis (L) inside a chamber (26) of said cylinder element (16) when said pressure exceeds said set pressure value, to cause said shutter device (6) to shift from said open position (PA) to said closed position (PC).

3. Shut-off valve (1) according to claim 2, and further comprising- a release rod (50) connected to said shutter device (6) and comprising a cylindrical portion(52) intended to receive internally at least partially said release tip (34), and a connecting portion (51) for connecting to said shutter device (6); and- retaining means (40) arranged for interacting with said release rod (50) to retain axially said shutter device (6) in said open position (PA), when said pressure is below said set pressure value, said release tip (34) being configured to interact with said retaining means (40) in order to release said shutter device (6) from said retaining means (40) such that said shutter device (6) can be taken to said closed position (PC) when said pressure is greater than said set pressure value.

4. Shut-off valve (1) according to claim 3, wherein said retaining means (40) comprises at least two retaining elements (44) that are reciprocally connected by at least one elastic retaining element (46) that retains elastically said retaining elements (44), at least two opposite retaining openings (55) being obtained in said cylindrical portion (52), said retaining elements (44) being arranged for engaging, each, a corresponding retaining opening (55) obtained in said cylindrical portion (52) so as to press therebetween said release rod (50) and prevent the latter from being moved along said axis (L).

5. Shut-off valve (1) according to claim 4, wherein each retaining element (44) comprises a revolving element and each elastic retaining element (46) comprises a torsion spring.

6. Shut-off valve (1) according to claim 4 or 5, wherein said retaining means (40) further comprises a bush (41) fitted to said valve body (2) and comprising a hollow central portion (42) that is substantially coaxial with said axis (L), said cylindrical portion (52) being fitted interposed between said central portion (42) and said release tip (34), at least two opposite windows (45) being obtained in said central portion (42), each window (45) being arranged alongside a respective retaining opening (55) such that said release tip (34) can interact with said retaining elements (44) through said retaining openings (55) and said windows (45).

7. Shut-off valve (1) according to any one of claims 4 to 6, wherein said release tip (34) is provided with a stem (36) provided at one end with a tip (37) configured to interact with said retaining elements (44), when said release tip (34) is moved along a closing direction (Yl), to move said retaining elements (44) away from said axis (L) and cause the disengagement of said release rod (50) when said retaining elements (44) exit a respective retaining housing (53) in which said retaining opening (55) is obtained.

8. Shut-off valve (1) according to any one of claims 3 to 7, and further comprising:- a reset rod (60) arranged for taking said shutter device (6) from said closed position (PC)to said open position (PA) when said pressure value is lower than said set value; in which said reset rod (60) and said release rod (50) are so sized and connected to said shutter device (6) that the hydraulic forces acting on said shutter device (6) are substantially the same.

9. Shut-off valve (1) according to claim 8, and further comprising a connecting rod (70) arranged for stiffly connecting said shutter device (6) to said reset rod (60) so that said shutter device (6) and said reset rod (60) are movable integrally and the hydraulic forces acting on said first face (48) and on said second face (49) are substantially the same.

10. Shut-off valve (1) according to any one of claims 2 to 9, wherein said sensor device (14) further comprises at least one calibrating elastic element (19) housed inside said chamber (26) and wound around said release tip (34), said calibrating elastic element (19) being connected at one end to said piston element (17) and at another end to a bottom (21) of said cylinder element (16) to constantly urge said thrust surface (18) to an upper internal surface (30) of said cylinder element (16), said set pressure value being a function of an elastic force associated with said calibrating elastic element (19).

11. Shut-off valve (1) according to any one of claims 6 to 10 as claim 8 is appended to claim 6 or 7 and claim 10 is appended to any one of claims 6 to 9, and further comprising an elastic thrust element (12) wound, at least partially, around a portion of said release rod (50) and to a portion of a shank (8) of said shutter device (6), said elastic thrust element (12) being connected at one end to an annular abutting element (39) fitted to said bush (41) and at another end to a protrusion (13) of said shutter device (6), said elastic thrust element (12) being configured to react on said protrusion (13) so as to promote an axial shift of said shutter device (6) along said axis (L), when said pressure exceeds the set pressure value.

12. Shut-off valve (1) according to claim 11, and further comprising seal means (80) arranged for confining said operating fluid in said inner passage (5), said seal means (80) comprising at least one first annular seal (81) arranged above in an annular seal seat (82) formed in said bush (41).

13. Shut-off valve (1) according to claim 12, wherein said seal means (80) further comprises a second annular seal (83) arranged below in a further annular seal seat (84) obtained in said valve body (2) at said reset rod (60).

14. Shut-off valve (1) according to any one of claims 8 to 13, as claim 10 is appended to claim 8 or 9 and claim 11 is appended to any one of claims 8 to 10, wherein said cylindrical surface (52) has a diameter (DI) and said reset rod (60) has a substantially cylindrical shapehaving a diameter (D2), said diameter (D2) of said reset rod (60) and said diameter (DI) of said cylindrical portion (52) are substantially the same for balancing the pressure acting on said shutter device (6).

15. Shut-off valve (1) according to any one of claims 2 to 14, wherein said sensor device (14) further comprises a pipe (22) arranged for placing said chamber (26) in flowing communication with a pick up zone (58) of said secondary circuit (104), such that a hydraulic pressure due to said fluid that circulates in said secondary circuit (104) can act on said thrust surface (18).

16. Shut-off valve (1) according to claim 15, wherein said pick up zone (58) is defined by an opening obtained on a portion of a delivery branch (106) of said secondary circuit (104) arranged upstream of said shut-off valve (1) with respect to a flowing direction (S) of a flow of fluid in said secondary circuit (104) or by an opening (31, 33) obtained on a portion of said valve body (2).

17. Cooling / heating plant (100) comprising:- a primary circuit (102) in which a coolant fluid is flowable in which said coolant fluid is flowable in use;- a secondary circuit (104) in which an operating fluid is flowable for cooling / heating an environment (101);- a heat exchanger (105) interposed between said primary circuit (102) and said secondary circuit (104) and configured to transfer thermal energy from said coolant fluid to said operating fluid;- a retaining device (108), installed on a return branch (107) of said secondary circuit (104) to enable said operating fluid to flow only in a flowing direction (S) and prevent the transit of fluid in a direction opposite the direction of said flowing direction (S), and- at least one shut-off valve (1) according to any one of claims 1 to 16; said shut-off valve (1) being arranged along a delivery branch (106) of said secondary circuit (104) and being configured to be driven between an open configuration (M) in which it allows a fluid circulation between an inlet (3) and an outlet (4) of a valve body (2) of said shut-off valve (1) and a closed configuration (N) in which it prevents a fluid circulation between said inlet (3) and said outlet (4) of said valve body (2) to prevent said coolant fluid reaching said environment (101) when a sensor device (14) of said shut-off valve (1) detects a pressure value of the fluid circulating in said secondary circuit (104) above a set pressure value.

18. Cooling / heating plant (100) according to claim 17, wherein said retaining device (108) comprises a check valve or a further shut-off valve (1).

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