WO2023139415A1

WO2023139415A1 - Safety apparatus for managing gas in conditioning plants

Info

Publication number: WO2023139415A1
Application number: PCT/IB2022/050591
Authority: WO
Inventors: Marco Caleffi
Original assignee: Caleffi S.P.A.
Priority date: 2022-01-24
Filing date: 2022-01-24
Publication date: 2023-07-27

Abstract

A safety apparatus (10), suitable for being installed in a conditioning plant (1) having a first circuit (5a) and a second circuit (5b), in which a first gaseous vector fluid and a second liquid vector fluid circulate respectively that exchange heat at an exchanger device (6), has a relief valve (11) and a detector (33), respectively suitable for evacuating a volume of undesired gas from the conditioning plant and detecting a presence of the undesired gas exiting the relief valve (11); the detector (33) of the safety apparatus is connected to a control unit (39) that is able to interrupt the circulation of the liquid vector fluid inside the plant at the moment in which a presence of undesired gas near the valve (11) is detected by the detector (33), so that all the volume of undesired gas contained in the plant is evacuated to the external environment.

Description

Safety apparatus for managing gas in conditioning plants

BACKGROUND OF THE INVENTION

The invention relates to a safety apparatus for managing a gaseous vector fluid circulating in a domestic or industrial conditioning plant.

PRIOR ART

Domestic or industrial conditioning plants enable a building to be cooled and/or heated by a thermal energy exchange between the external environment and one or more internal environments of the building to be heated and/or cooled. Among the aforementioned conditioning plants, heat pump conditioning plants can be included, which can be used with the dual function of heating an environment during the winter period, and cooling an environment during the summer period.

There are heat pump conditioning plants that provide a first circuit in which a first vector fluid circulates, for example a gas or a liquid, and a second circuit in which a second vector fluid circulates, for example a gas or a liquid. These first and second vector fluids are suitable for exchanging thermal energy in the form of heat at an exchanger device, so as to heat and/or cool one or more internal environments of the building in which the conditioning plant is installed.

In one particular type of heat pump conditioning plant, in the first circuit a gas is used as vector fluid and in the second circuit a liquid is used as vector fluid, for example water. In particular, the first circuit is provided in contact with the external environment, whereas the second circuit is provided in contact with the internal environment of the building to be heated and/or cooled. In this type of heat pump conditioning plant, the use of gas with a low environmental impact, such as for example propane, as vector fluid to be used in the first circuit is increasingly widespread.

However, propane is an explosive and highly flammable gas, so using propane as a vector fluid inside a conditioning plant can be a potential human health hazard. For example, in the event of breakage of the exchanger device, the aforesaid gas could enter in the second circuit, intended on the other hand for the circulation of the liquid vector fluid, for example water. The breakage of the exchanger device could thus lead to the accumulation of the potentially harmful gaseous vector fluid in critical points, creating situations that could be hazardous. Propane is further classified as an asphyxiating gas, i.e. as a gas that prevents the process of cellular respiration if it is present in air in high concentration. It would thus be necessary to detect a possible anomalous concentration of the potentially hazardous gas, like propane, exiting the conditioning plant to prevent an accumulation inside an internal environment that is potentially harmful to human health.

As a result, using a potentially hazardous gas, like propane, as a vector fluid to be inserted into conditioning plants makes it necessary to install safety apparatuses in the conditioning plant that prevent the occurrence of hazardous situations in the event of possible gas leaks from the plant due to plant faults or malfunctions.

In the conditioning plants that are currently marketed, apparatuses are inserted for the controlled evacuation of gas, such as for example air, from the plants themselves. The presence of air inside the conditioning plant, more precisely inside the parts of the circuit intended for the circulation of the liquid vector fluid, can be harmful to the operation of the plant, because it can generate corrosive phenomena, cavitation, etc..

Some of these apparatuses for the controlled evacuation of gas involve, for example, the controlled evacuation of bubbles or pockets of gas inside the conditioning plant, manually or automatically. Others, on the other hand, enable the microbubbles of gas dissolved in the liquid fluid vector to be eliminated.

The apparatuses for the controlled evacuation of gas currently marketed thus enable the gas to be evacuated from critical points of the plant. However, successive passages of the vector fluid in the conditioning plant are necessary to obtain an efficient elimination of the gas contained inside the plant.

In the light of the above, and given the constantly increasing use of potentially hazardous gases, like propane, in domestic and industrial conditioning plants, a need is felt keenly to improve the currently known apparatuses for the controlled evacuation of gas and to develop safety apparatuses that avoid the occurrence of potentially hazardous situations for human health during the operation of the plant.

OBJECT OF THE INVENTION

The object of the present invention is to propose a safety apparatus for conditioning plants that is able to meet the aforementioned needs for safety of conditioning plants.

BRIEF DESCRIPTION OF THE INVENTION

This object is achieved by a safety apparatus that is suitable for being installed in a conditioning plant, according to the first claim.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to better understand the invention, a description is given below of a non-limiting exemplary embodiment thereof, illustrated in the attached drawings in which: Fig.1 illustrates a partially sectional frontal view of a safety apparatus suitable for being installed in a conditioning plant according to the invention;

Fig.2 illustrates an enlarged detail of the safety apparatus of Fig.1;

Fig.3 is a schematic representation of a conditioning plant into which the safety apparatus of Fig.1 is inserted.

DETAILED DESCRIPTION OF THE INVENTION

The safety apparatus illustrated in Fig.l, indicated overall with 10, is suitable for being installed in a domestic or industrial conditioning plant like, for example, the conditioning plant 1 illustrated in Fig.3.

The conditioning plant 1 is a plant installed in a building for heating and/or cooling an environment 2. The conditioning plant 1 comprises an internal unit 3, positioned inside the environment 2 of the building to be heated and/or cooled, and an external unit 4, positioned outside the environment 2 of the building to be heated and/or cooled. More in particular, the external unit 4 is positioned outside the building to be heated and/or cooled.

The internal unit 3 and the external unit 4 of the conditioning plant 1 are reciprocally connected by a first circuit 5a in which a first vector fluid circulates, and a second circuit 5b in which a second vector fluid circulates. The first circuit 5a is provided inside the external unit 4, positioned outside the building to be heated and/or cooled. The second circuit 5b is on the other hand provided partially inside the internal unit 3, in contact with the internal environment 2 of the building to be heated and/or cooled, and partially in contact with the external environment, as shown in Fig.3. In particular, in the conditioning plant 1 considered in the present description, in the first circuit 5a a gaseous vector fluid is provided, for example propane, and in the second circuit 5b a liquid vector fluid, for example water, is provided.

The first gaseous vector fluid and the second liquid vector fluid, circulating respectively in the first circuit 5a and in the second circuit 5b, are able to exchange thermal energy in the form of heat via an exchanger device 6, in order to heat and/or to cool the internal environment 2 of the building in which the conditioning plant is installed.

In Fig.3, some components present in the second circuit 5b are represented explicitly, in particular in the part of the second circuit 5b in contact with the external environment. These components are the safety apparatus 10, a motor-driven valve 40 and a circulator device 50, which are serially connected to one another. In particular, the safety apparatus 10, the motor- driven valve 40 and the circulator device 50 are serially connected in the path of the vector fluid from the exchanger device 6 to the internal unit 3 according to the direction of the arrow shown in Fig.3, exactly in the order in which they are cited in this paragraph.

With reference to Figs.1,2, the safety apparatus 10 for evacuating gas comprises a relief valve 11 that extends along the direction of a first axis W. The relief valve 11 has an inlet 12 and an outlet 13 that are respectively suitable for permitting the entry and exit of a vector fluid circulating in the aforesaid conditioning plant. More in particular, the inlet 12 enables the vector fluid coming from the external unit 4 of the conditioning plant to enter the relief valve 11, and the outlet 13 enables the vector fluid to exit from the relief valve 11 to the motor-driven valve 40.

In an upper portion I la of the relief valve 11, a chamber 14 is provided. The chamber 14 has a substantially cylindrical shape.

Inside the chamber 14, a float 18 is housed that is able to float on the surface of the liquid vector fluid that circulates in the conditioning plant. The float 18 is connected to a rocker arm 20 by a first end 20a of the rocker arm 20 itself. A second end 20b of the rocker arm 20 is hinged rotatably on a pin 21. The pin 21 is fixed integrally to a wall of the relief valve 11. The rocker arm 20 is able to rotate on a vertical plane around a rotation axis X passing through the pin 21 and orthogonal to the aforesaid vertical plane. An upward or downward translation movement of the float 18 along a direction parallel to the first axis W of the relief valve 11 involves a rotation of the rocker arm 20 around the rotation axis X, as will be clearer further on in the description.

The chamber 14 is closed above by a cap 25, screwed tightly on the upper part of the chamber 14 by a thread 15 with the interposition of a first gasket 27, for example an O-ring. The cap 25 has an upper opening 16, arranged in a portion of the cap 25 near an edge 17 of the chamber 14.

At the opening 16, the cap 25 is so shaped as to have a protrusion 22 that extends vertically upwards. The protrusion 22 extends vertically along a second axis T parallel to the first axis W of the relief valve 11.

The protrusion 22 has, above, a closing portion 24. The protrusion 22 has side openings 23 that are suitable for evacuating the gas from the plant.

Inside the protrusion 22, a shutter device 19 is housed. The seal between the shutter device 19 and the protrusion 22 is assured by a further gasket 28, for example an O-ring. The shutter device 19 comprises a substantially cylindrical central body 29 that extends vertically along the aforesaid axis T. In a lower portion, the central body 29 of the shutter device 19 has two loop portions 30 and 31, protruding with respect to the substantially cylindrical structure of the central body itself. The two loop portions 30 and 31 of the central body 29 of the shutter device 19 identify two limit positions, respectively lower and upper, that the rocker arm 20 can reach in rotation around the rotation axis X. At an upper end, the central body 29 of the shutter device 19 is inserted into a loop portion 32. On the shutter device 19, a coil spring 26 acts to counter the action of the weight force of the float 18 that is transmitted to the shutter device 19 through the rocker arm 20.

The shutter device 19 is able to move in vertical translation downwards or upwards along the axis T of the protrusion 22 through the action of the float 18 or of the spring 26, as will be seen below.

Above the protrusion 22, the safety apparatus 10 has a gas detector 33. More in particular, the side openings 23 face an inner chamber 34 of the gas detector 33.

Inside the aforesaid inner chamber 34 of the gas detector 33, there is a sensor element 35 which is sensitive to the gas that is potentially hazardous to human health if it is delivered in high concentrations into the environment 2 of the building to be heated and/or cooled, i.e. in this embodiment propane. The sensor element 35 which is sensitive to the gas is connected to a control unit 39.

The motor-driven valve 40 and the circulator device 50 are further connected to the same control unit 39.

The operation of the safety apparatus 10, inserted inside the conditioning plant 1, will now be disclosed.

In optimum operating conditions, in the second circuit 5b illustrated in Fig.3 the liquid vector fluid, i.e. in this embodiment water, circulates. The relief valve 11, inserted into the second circuit 5b, is then traversed by the water from the inlet 12 to the outlet 13. Water occupies a certain volume of the chamber 14, forcing the float 18 to float on the free surface of the water in an upper position (not shown). In these operating conditions, the float 18 rises and no longer exerts weight force on the rocker arm 20 and thus on the shutter device 19, so the spring 26 pushes the shutter device 19 upwards. The loop portion 31 compresses the gasket 28, preventing the gas from flowing along the shutter device 19 and from being evacuated through the side openings 23. As there is no evacuation of gas, the gas detector 33 does not detect any fault and the control unit 39 continues to supply the motor-driven valve 40 and the circulator device 50 to permit the liquid vector fluid to circulate in the plant. In non-optimum operating conditions, as mentioned previously, an accumulation of gas could occur in parts of the circuit intended for circulation of a liquid vector fluid. In other words, in non-optimum operating conditions, for example following a breakage of the exchanger device 6, in the second circuit 5b the gaseous fluid vector coming from the first circuit 5a could enter circulation.

The relief valve 11 inserted into the second circuit 5b is then traversed by the water and by a certain quantity of gas, which can be in the form of pockets or bubbles, or in the form of microbubbles dissolved in the liquid. One part of the volume of the chamber 14, previously occupied by the water, will be occupied by the gas. More precisely, the gas present in the second circuit 5b accumulates in the upper part of the chamber 14, forcing the water to a lower level. The float 18, suitable for floating on the free surface of the water, will then move to a lower position, as represented in Figs.1,2. In these operating conditions, the float 18 pulls the rocker arm 20 downwards, which, in turn, pulls the shutter device 19 downwards, in contrast to the action of the spring 26. The loop portion 31 thus no longer compresses the gasket 28, so that the undesired gas is free to flow along the shutter device 19 and to be evacuated through the side openings 23. The gas exiting the side openings 23, at this point, is delivered inside the internal chamber 34 of the gas detector 33. As soon as the gas detector 33 detects a presence of gas inside the internal chamber 34, the control unit 39 interrupts the supply of the motor-driven valve 40 and/or of the circulator device 50 to interrupt the circulation of the vector fluid in the plant and permit an immediate and almost total evacuation of the undesired gas in the external environment before it continues to circulate inside the damaged plant.

One advantage of the safety apparatus 10 is to enable the evacuation of most of the gas accumulated by mistake in the second circuit 5b already at the first passage of the liquid vector fluid in that same part of the circuit. In fact, the interruption of the supply of the motor-driven valve 40 and/or of the circulator device 50 to interrupt the circulation of the vector fluid in the plant enables the relief valve 11 to evacuate and disperse in the external environment all the quantity of gas that has leaked from the first circuit 5a following the breakage of the exchanger device 6, before large quantities of gas can reach parts of the plant inside the building to be heated and/or cooled.

Another advantage of the safety apparatus 10 is that, as the safety apparatus 10 is fitted upstream of the motor-driven valve 40 and the circulator device 50, the potentially hazardous gas that has accumulated in the second circuit 5b is evacuated independently of the operation or non-operation of the motor-driven valve 40 and the circulator device 50.

A further advantage of the safety apparatus 10 is the fact that the potentially hazardous gas that has accumulated in the second circuit 5b can be evacuated even in the event of a power cut. In fact, in this case, the gas detector would not be supplied and, in turn, could not send a signal to the control unit 39 because of the interruption of the supply of the motor-driven valve 40 and/or of the circulator device 50. Nevertheless, as the operation of the relief valve 11 is purely mechanical, the evacuation of the gas would still be performed. Further, the motor-driven valve 40 and the circulator device 50 would still be unsupplied, so the interruption of the circulation of the vector fluid in the plant and the safety of the system would still be guaranteed.

Variations on the configuration of the components disclosed above are possible in function of the application needs.

Claims

CLAIMS Safety apparatus (10) suitable for being installed in a domestic or industrial conditioning plant (1) comprising a first circuit (5a) and a second circuit (5b), in which a first gaseous vector fluid and a second liquid vector fluid circulate respectively, the first gaseous vector fluid and the second liquid vector fluid being suitable for exchanging energy in the form of heat via an exchanger device (6), the safety apparatus (10) comprising a relief valve (11), suitable for evacuating a volume of undesired gas from the conditioning plant, in combination with a detector (33), suitable for detecting a presence of the undesired gas exiting the relief valve (11). Safety apparatus (10) according to claim 1, wherein the detector (33) comprises a sensor element (35) that is sensitive to the undesired gas, the sensor element (35) being connected to a control unit (39) to interrupt the circulation of the liquid vector fluid in the conditioning plant if a concentration of the undesired gas is detected by the sensor element (35). Safety apparatus (10) according to claim 1 or 2, wherein the relief valve (11) and the detector (33) are inserted into the second circuit (5b) of the conditioning plant (1) in a position in contact with the external environment with respect to a building in which the conditioning plant (1) is installed. Safety apparatus (10) according to any one of the preceding claims, wherein the relief valve (11) extends along a first axis (W) and comprises an inlet (12) and an outlet (13), respectively for the entry and the exit of the liquid vector fluid circulating in the second circuit (5b), and a chamber (14) arranged above along the first axis (W) suitable for receiving a given volume of liquid vector fluid circulating in the second circuit (5b) and a given volume of the possible undesired gas that has to be evacuated from the plant. Safety apparatus (10) according to claim 4, wherein the chamber (14) is closed above by a cap (25) having a protrusion (22) on which openings (23) are obtained for the exit of the undesired gas that has to be evacuated from the plant. Safety apparatus (10) according to claim 5, wherein the protrusion (22) is suitable for housing a shutter device (19) that is movable vertically along a second axis (T), the shutter device (19) being suitable for opening or closing the communication between the chamber (14) and the openings (23), such that in the open position of the shutter device (19) the undesired gas, that has to be evacuated from the plant, exits. Safety apparatus (10) according to claim 6, wherein a float (18) opposed to a spring (26) acts on the shutter device (19), wherein the float (18) is connected to the shutter device (19) by a rocker arm (20), the float (18) being able to float on the surface of the liquid vector fluid present inside the chamber (14), and being movable vertically along a direction parallel to the first axis (W) in function of the quantity of liquid vector fluid and/or in function of the quantity of undesired gas contained inside the chamber (14). Safety apparatus (10) according to claim 7, wherein the rocker arm (20) is connected by a first end (20a) to the movable float (18), and by a second end (20b) to a fixed pin (21), the rocker arm (20) being able to rotate on a vertical plane around a rotation axis (X) passing through the pin (21), such that an upward or downward translation movement of the float (18) in function of the quantity of liquid vector fluid and/or in function of the quantity of undesired gas contained inside the chamber (14) involves a rotation of the rocker arm (20) around the rotation axis (X). Safety apparatus (10) according to claim 8, wherein, when the level of the liquid vector fluid contained in the chamber (14) lowers owing to the presence of a volume of undesired gas to be evacuated, a downward translation of the float (18) occurs integrally with a downward rotation of the rocker arm (20) and a downward translation of the shutter device (19) to an open position, to enable the volume of undesired gas to be evacuated from the plant through the openings (23). Safety apparatus (10) according to any one of claims 5 to 9, wherein the detector (33) is positioned above the relief valve (11) along the first axis (W), and comprises a chamber (34), which is suitable for receiving the undesired gas that is evacuated by the relief valve (11) via the openings (23). Conditioning plant (1) comprising a motor-driven valve (40) and a circulator device (50) fitted upstream of a safety apparatus (10) according to one of the preceding claims, the safety apparatus (10), the motor-driven valve (40) and the circulator device (50) being connected to a control unit (39) to interrupt the circulation of the liquid vector fluid in the conditioning plant if a concentration of undesired gas that is hazardous to the human health is detected by the safety apparatus (10).