Fire protection system with reduced consumption and improved freeze protection

Abstract

The invention relates to a fire protection system (1) having a sprinkler network (4), the system comprising: - sprinkler pipes (3) configured to convey fluid from a tank (2) configured to store a predefined volume of fluid to the sprinkler network (4), the sprinkler pipes (3) and the tank (2) forming a closed fluid circuit; and - a maintenance device (5) connected to the closed fluid circuit and comprising a filter (7) configured to filter the water in the closed fluid circuit, the maintenance device (5) comprising an inlet pipe (11) configured to be fitted to the tank (2) so as to collect fluid and an outlet pipe (12) configured to be connected to the tank (2), close to the top of the tank (2), so as to inject the fluid collected by the inlet pipe (11) into the tank (2).

Description

[0001] DESCRIPTION

[0002] TITLE: Fire protection system with reduced energy consumption and improved freeze protection

[0003] TECHNICAL FIELD

[0004] This application concerns sprinkler systems. More specifically, this application concerns the maintenance of these sprinkler systems.

[0005] STATE OF THE ART

[0006] A sprinkler fire protection system comprises one or more tanks configured to store a predetermined volume of fluid, sprinkler lines (or antennas) carrying this fluid under pressure, and sprinklers configured to automatically spray a fire when the ambient air reaches a predetermined temperature and / or when smoke is detected. The fluid typically consists of water.

[0007] These protection systems have proven their effectiveness. However, to ensure the system's continued operation, periodic maintenance is required.

[0008] Some of these actions, however, result in the waste of a significant volume of water. For example, current national and international regulations require that the tank (with a volume of several hundred cubic meters) and the sprinkler lines be drained periodically (the interval depends on the applicable regulations and is generally between three and ten years). Such draining is also necessary for maintenance or part replacement. Another example concerns the pump unit, which circulates water through the sprinkler lines and must undergo weekly tests that also consume water. The same applies to mandatory test visits and bell tests.The Applicant thus estimates that the volume of drinking water consumed to check and guarantee the operation of protection systems in France amounts to more than three billion liters each year, which corresponds to the annual water consumption of a French city of 55,000 inhabitants.

[0009] Some of these actions, necessary for the operation of the protection system, are energy-intensive. Indeed, it is essential to prevent the water in the tank from freezing, regardless of the ambient temperature. The formation of an ice layer on the tank's surface can deform the tank when water is drawn in if the protection system is activated (during a fire, for example). Modern tanks therefore include an anti-freeze device with a heating element immersed in the tank, which activates as soon as the ambient temperature drops too low, generally around 6°C. However, the electricity consumption of such an anti-freeze device is on the order of several kilowatt-hours (kWh). Other actions necessary for the operation of the protection system are also energy-intensive.Indeed, it is essential to prevent the water in the tank from freezing, regardless of the ambient temperature. The formation of an ice layer on the tank's surface can deform it when water is drawn in if the protection system is activated (for example, during a fire). Modern tanks therefore include an anti-freeze device with a heating element immersed in the tank, which activates as soon as the ambient temperature drops too low, generally around 6°C. However, the electricity consumption of such an anti-freeze device is on the order of several kilowatt-hours (kWh).

[0010] EXPOSED

[0011] One aim of this application is to address the aforementioned drawbacks by proposing a solution that reduces the volume of water required to check the operation of protection systems, without impacting their operation, and reduces the electrical consumption of the protection system while ensuring its integrity.

[0012] To this end, a fire protection system using a sprinkler network is proposed, according to a first aspect, comprising:

[0013] - spray lines configured to transport fluid from a tank configured to store a predefined volume of fluid to the sprinkler network, the spray lines and the tank forming a closed fluid circuit; and

[0014] - a maintenance device connected to the closed fluid circuit and comprising a filter configured to filter the water from the closed fluid circuit, the maintenance device comprising an inlet pipe configured to be mounted on the tank so as to draw fluid and an outlet pipe configured to be connected to the tank, near a top of the tank, so as to inject the fluid drawn by the inlet pipe into the tank.

[0015] Some preferred but not exhaustive characteristics of the protection system according to the first aspect are the following, taken individually or in combination:

[0016] - the filter includes at least one of a magnetic filter and a sludge trap;

[0017] - the inlet pipe has an upstream end mounted on the tank so as to draw the fluid and a downstream end connected to the filter, the inlet pipe is: either mounted on a lower part of the tank, near a bottom of the tank; or on a higher part of the tank, near the top, the maintenance device further including a self-priming pump so as to draw the fluid;

[0018] - the inlet pipe is configured to be mounted on a tank drain valve;

[0019] - the outlet pipe has an upstream end connected to the filter and a downstream end connected to the tank, so as to inject the fluid filtered by the filter into the tank;

[0020] - the protection system further comprising a motor-pump unit, configured to draw the fluid from the tank and inject it into the spray lines, and a discharge line having a first end connected to the motor-pump unit and a second end connected to the outlet line or to the tank;

[0021] - the protection system further comprising heating means fitted onto the outlet pipe, for example a heating cord wrapped around the outlet pipe;

[0022] - the protection system further includes a thermal probe configured to measure the temperature of the fluid in the tank;

[0023] - the tank further includes a convection chamber mounted near a top of the tank, the outlet pipe being configured to open into the convection chamber;

[0024] - the maintenance device further includes a pump configured to draw fluid from the tank and circulate it through the maintenance device via the filter, between the inlet and outlet pipes.

[0025] According to a second aspect, a set is proposed comprising a fire protection system by sprinkler network according to the first aspect and a tank fluidly connected to the sprinkler lines, the inlet line of the maintenance device being mounted on a lower part of the tank and the outlet line of the maintenance device being connected to the top of the tank, the filter of the maintenance device being configured to filter fluid stored in the tank.

[0026] According to a third aspect, a maintenance procedure for a fire protection system using a sprinkler network is proposed, conforming to the second aspect and comprising the following steps:

[0027] - suction of a volume of fluid from the tank;

[0028] - filtration of the volume of fluid thus aspirated; and

[0029] - injection of the filtered fluid volume into the tank.

[0030] Some preferred but not exhaustive characteristics of the maintenance process according to the third aspect are as follows, taken individually or in combination:

[0031] - the maintenance process also includes a step of heating the filtered fluid before the injection step;

[0032] - The heating stage is implemented when the fluid temperature is below a predefined threshold temperature; and / or

[0033] - the protection system further includes a motor-pump unit configured to draw fluid from the tank and inject it into the spray lines of the protection system and the maintenance process further includes the filtration of a cooling fluid from the motor-pump unit.

[0034] DESCRIPTION OF THE FIGURES

[0035] Other features, purposes, and advantages will become apparent from the following description, which is purely illustrative and not exhaustive, and should be read in conjunction with the attached drawings on which:

[0036] Figure 1 schematically illustrates an example of a fire protection system using a sprinkler network conforming to an embodiment; Figure 2 is a flowchart of steps of an example of a maintenance procedure for a fire protection system using a sprinkler network.

[0037] Across all figures, similar elements bear identical references.

[0038] DETAILED DESCRIPTION

[0039] A fire protection system 1 for an installation using a sprinkler network 4 comprises:

[0040] - spray pipes 3 configured to transport fluid from a tank 2 configured to store a predefined volume of fluid to the sprinkler network 4; and

[0041] - a maintenance device 5.

[0042] In what follows, the invention will be described in the case where the fluid comprises water. This is not, however, limiting; the present description is applicable when another fluid is used by the protection system 1.

[0043] The spray pipes 3 are in fluidic communication with the tank 2. The spray pipes 3 and the tank 2 form a closed water circuit, so that the protection system 1 is independent of the public sewage network, thus ensuring its operation even in the event of a public network failure. The protection system 1 also includes a motor-pump unit 6 configured to draw water from the tank 2 and circulate it under pressure through the spray pipes 3.

[0044] The volume of tank 2 depends on the size of the installation to be protected. Depending on the installation, the protection system 1 may include several tanks 2 connected to the spray lines 3.

[0045] The sprinkler lines (Type 3) contain water, usually under pressure, and are configured to automatically spray a fire when the ambient air reaches a predetermined temperature and / or when smoke is detected. Since the operation of sprinkler lines (Type 3) is conventional, it will not be described in further detail here.

[0046] In order to reduce, or even eliminate, water losses induced by the maintenance of the protection systems 1, the maintenance device 5 includes a filter 7 configured to filter the water from the closed fluid circuit of the protection system 1. The filtration of the water makes it possible to remove the particles present in the fluid circuit, and in particular in the tank 2, and thus avoid the need to periodically drain and clean the tank 2.

[0047] The filter 7 may, for example, include a magnetic filter 8 configured to filter ferromagnetic particles present in the water. The magnetic filter 8 may include a settling tank, which is mounted on the closed water circuit; a magnetic core mounted in the settling tank and configured to attract and extract ferromagnetic particles present in the water flowing through the magnetic filter 8; and a drain valve configured to allow the removal of the ferromagnetic particles extracted by the magnetic core. An example of a magnetic filter 8 that could be used is the DIRTMAG® flanged settling tank with magnet and insulating shell, commercially available from the Caleffi brand. The ability of the magnetic filter 8 to filter ferromagnetic particles depends on the type of magnetic core chosen, the water flow rate through the filter 7, the duration and frequency of filtration of the magnetic filter 8, and the size of the particles.For example, the magnetic core may include a neodymium magnet; the flow rate in the magnetic filter 8 may be greater than or equal to 5 m. 3 and go up to several tens of meters 3 , for example, on the order of 8 to 10 m 3 ; the filtration of the water from tank 2 can be carried out every day for 12 hours; and the size of the ferromagnetic particles is generally less than or equal to 5 m.

[0048] The filter 7 may also include a sludge trap 9, which can be mounted in series with the magnetic filter 8 or integrated directly into the magnetic filter 8. The sludge trap may include a sieve with a mesh size chosen according to the type of impurities likely to be present in the tank 2 and the frequency of cleaning the filter 7 to prevent it from becoming clogged. For example, the mesh size may be between 5 µm and 100 µm. Weekly cleaning of the filter 7 is then sufficient to prevent clogging by impurities while ensuring effective filtration of the closed-loop water.

[0049] The maintenance device 5 further includes a pump 10 configured to draw water from tank 2, circulate it through filter 7, and return it to tank 2. Pump 10 is thus fluidly connected to tank 2 and filter 7 via dedicated pipes. Pump 10 may be a single-unit centrifugal pump adapted to the volume of tank 2. Pump 10 may, for example, have a flow rate between 5 m 3 / h and 15 m 3 / h, for example on the order of 10 m 3 / h for a 2-tank of 750 m 3 and a pressure between 0.5 bar and 1.5 bar, for example around 1 bar for a 750 m³ tank 3 .

[0050] The maintenance device 5 can be mounted on an existing protection system 1 that is already in place in a given installation, or integrated directly into a new protection system 1.

[0051] To this end and in order to reduce the electrical consumption of the protection system, the maintenance device 5 includes an inlet pipe 11 mounted on the tank 2 in order to take water from the tank 2 and circulate it through the filter 7, and an outlet pipe 12 which receives the water taken by the inlet pipe 11 and filtered by the filter 7 and is configured to inject it into the tank 2.

[0052] The filter 7 is placed between the inlet pipe 11 and the outlet pipe 12 so as to filter the water taken from the inlet pipe 11 before its reinjection into the tank through the outlet pipe 12.

[0053] The pump 10 is also fluidly connected to the tank and the filter 7 via the inlet pipes 11 and outlet pipes 12.

[0054] The inlet pipe 11 is preferably mounted near the bottom 13 of the tank 2 so that the pump 10 draws water from the bottom of the tank 2. The water at the bottom 13 of the tank 2 is indeed at a higher pressure than the water at its surface, which reduces the power required for the pump 10 to circulate the water through the filter 7 and also allows the pump to draw in any particles that may be present at the bottom 13 of the tank 2. For example, the inlet pipe 11 can be mounted on the drain valve of the tank 2: such a drain valve is indeed already present on most tanks 2 to allow for their periodic emptying.

[0055] The outlet pipe 12 is preferably mounted near the top 14 of tank 2 so as to inject the filtered water close to the surface of the water in tank 2. Injecting at the top of tank 2 offers several advantages. The water at the surface is generally colder than the water at the bottom 13 of tank 2: injecting the filtered water at the top of tank 2 thus warms the surface water and reduces the risk of freezing. Furthermore, the suction at the bottom 13 of tank 2, combined with the injection at the top of tank 2, circulates the water within tank 2, creating water movement that further reduces the risk of the water surface freezing. This configuration of the inlet pipes 11 and outlet pipes 12 of the maintenance device 5 thus reduces the risk of freezing of the surface water and, consequently, reduces the heating requirements of the water in tank 2.

[0056] If tank 2 is buried (basin), the maintenance device 5 can be placed on the surface. In this case, the inlet pipe 11 and the outlet pipe 12 can be connected near the top 14 of the buried tank 2. Furthermore, the pump 10 can be a self-priming type, as the water pressure at the top 14 of tank 2 is lower than at its bottom 13.

[0057] To further limit the risk of freezing, the maintenance device 5 may also include heating means 15 for the outlet pipe 12 and / or the inlet pipe 11. These heating means 15 may include, in particular, a conduction heater fitted onto the pipe(s) 11, 12, such as a heating cable. The heating cable may, for example, be wrapped around the inlet pipe 11 and the outlet pipe 12. The heating means 15 thus allow, when necessary, the water treated by the maintenance device 10 to be heated.

[0058] When the outlet pipe 12 is mounted near the top 14 of the tank 2, the length of the pipes 11, 12 of the maintenance device 5 is sufficient to allow the heating of the water drawn in through the inlet pipe 11 and filtered. For example, for a tank 2 of 750 m 3The height of tank 2 is generally around 9 m. The length of the pipes can therefore be around ten meters while the length of the heating cord (before winding) can be for example around fifteen meters, which allows the temperature of the filtered water to be raised by at least 0.1 °C between its collection at the bottom of tank 2 and its injection into tank 2 (for a heating cord power of around 10 W / m).

[0059] Where appropriate, the assembly formed by the outlet pipe 12 and / or the inlet pipe 11 and the heating means 15 may be insulated in order to improve the heat transfer to the filtered water which circulates in the pipes 11, 12.

[0060] Preferably, the heating means 15 are only activated in the event of a risk of freezing. To this end, in a first embodiment, the maintenance device 5 includes a thermal probe 16 configured to measure the water temperature in the tank 2. The heating means 15 are then only activated when the water temperature is below a predefined temperature, for example, less than or equal to 1°C. In this embodiment, it is therefore the water temperature in the tank 2, and not the ambient temperature, that serves as the setpoint for activating the heating means 15. The thermal probe 16 may, for example, include an immersion heater submerged in the tank 2, preferably near or at the surface of the water, as surface water is generally colder and therefore more likely to freeze than water at the bottom 13 of tank 2.Optionally, tank 2 further includes a convection chamber 17 mounted near the top 14 of tank 2. The convection chamber 17 may include one or more walls, for example, metal sheets, fixed to the walls of tank 2 at the water surface so as to contain water from tank 2. The sheet(s) are connected to each other to form a sleeve open at two opposite ends (one end facing the bottom 13 of tank 2 while the other end faces the top 14, near the water surface). The sleeve may therefore have a generally cylindrical shape with any cross-section (for example, parallelepiped or ovoid). The water contained in the convection chamber 17 is thus in fluidic communication with the water contained in the rest of tank 2.

[0061] The walls of the convection chamber 17 delimit a volume of water which is very small compared to the total volume of the tank 2. For example, the volume of water delimited by the convection chamber 17 is less than 5% of the total volume of the tank 2.

[0062] The outlet pipe 12 preferably opens into the convection chamber 17 so that the filtered water is injected through pipe 12 into the convection chamber 17. Since the water injected through the outlet pipe 12 and filtered is warmer than the water on the surface of the tank 2 (because it has been drawn from the bottom 13 of tank 2 and, if necessary, heated by the heating means 15), the water injected through the outlet pipe 12 and filtered heats the water contained in the convection chamber 17. As the volume of water delimited by the convection chamber 17 is very small compared to the total volume of water in the tank 2, the temperature of the water in the convection chamber 17 necessarily increases more rapidly than if the filtered water were injected directly into the tank 2, which reduces the heating requirements of the injected and filtered water.It is sufficient that the water in the convection chamber 17 be sufficiently warm not to freeze to avoid the risk of damage to the tank 2: indeed, even if the surface water in the rest of the tank 2 were to freeze, the water present on the surface in the convection chamber 17 would remain liquid, which would allow the water to be drawn up by the motor-pump unit 6 of the protection system 1 without risk of damaging the tank 2.

[0063] When the tank 2 includes a convection chamber 17, the thermal probe 16 is preferably placed in the convection chamber 17, or even immersed in the water contained in the convection chamber 17, preferably near the surface, so as to heat the injected and filtered water only when the volume of water delimited by the convection chamber 17 is likely to freeze.

[0064] Note that the activation of the heating means 15 only when the water temperature is below the threshold temperature (and rather than when the ambient temperature becomes too low), combined with the movement of the water by means of the maintenance device 5 and the injection of filtered water into the convection chamber 17 by means of the outlet pipe 12, makes it possible to divide by at least three the electrical power required to prevent the water on the surface of the tank 2 from freezing.

[0065] The protection system 1 further includes a cooling system for the pump unit 6, comprising a supply line configured to deliver cooling water to the motor of the pump unit 6 for cooling purposes, and a discharge line 19 configured to discharge the water after the motor has cooled. The discharge line 19 can be connected to the outlet line 12 of the maintenance device 5, so that the water used to cool the pump unit 6 is injected into tank 2 along with the filtered water. This water is, in fact, at a higher temperature than the water drawn from the bottom 13 of tank 2, since it has been heated by the motor of the pump unit 6, which further heats the water in tank 2.Furthermore, the connection to the outlet pipe 12 (rather than the inlet pipe 11) of the maintenance device 5 ensures the cooling, and therefore the operation, of the motor-pump unit 6, even in the event of a malfunction of the maintenance device 5.

[0066] Injecting the water used to cool the motor-pump unit 6 into tank 2 also allows it to be filtered and thus avoids sending it to the sewer, since it is mixed with the water in tank 2 on which the maintenance device 5, and therefore the filter 7, is mounted.

[0067] When the protection system 1 includes several tanks 2, the protection system 1 may include a maintenance device 5 per tank 2. It may also include as many inlet pipes 11 and outlet pipes 12 as there are tanks.

[0068] Alternatively, the protection system 1 may include a single maintenance device 5 connected to several tanks 2. The maintenance device 5 then includes as many secondary inlet pipes and secondary outlet pipes as there are tanks 2 to be maintained, the secondary inlet pipes and secondary outlet pipes being able to be connected to the inlet pipe 11 and the outlet pipe 12, respectively, of the maintenance device 5. Preferably, a maintenance device 5 is connected to at most two tanks 2.

[0069] Tank 2 can be serviced periodically, for example, during a period between 8 a.m. and 3 p.m. For a 750 m³ tank 2 3With the magnetic filter 8 and the pump 10 described above, a 12-hour period allows the entire volume of tank 2 to be filtered in one week. However, when the protection system 1 also includes a thermal probe 16 and, where applicable, heating means 15, maintenance of tank 2 can also be carried out when the water temperature falls below the predefined temperature to allow water circulation in tank 2 and in the outlet pipe 12.

[0070] For this purpose, the maintenance device 5 may include a controller 20 configured to execute operating cycles of the maintenance device 5, and a switch to allow an operator to modify the operating cycle executed by the controller.

[0071] The first operating cycle of the automaton is an automatic cycle corresponding to the periodic maintenance of tank 2, the period and duration of which can be adjusted according to the number of tanks 2, the location of the protection system 1 (type of installation (and therefore volume of impurities and particles likely to be generated), geographical location (weather conditions), etc.) and the type of installation to be protected.

[0072] A second operating cycle of the automated system is a manual cycle in which the maintenance device 5 is forced to start in order to verify its operation (maintenance, checking the pump 10, etc.). The manual operating cycle can have a predetermined duration, for example, twenty minutes.

[0073] A third operating cycle of the automated system corresponds to the shutdown of the maintenance device 5.

[0074] The protection system 1 may also include conventional safety means. Typically, the alarm cable normally connected to the heating pin can be connected to the thermal probe 16.

[0075] It should be noted that the presence of the maintenance device 5 does not affect the operation of the protection system 1. In the event of a fire, the sprinklers 4 continue to automatically spray the fire source as soon as the ambient air reaches a predetermined temperature and / or smoke is detected, regardless of the operation of the maintenance device 5.

[0076] The maintenance device 5 can be placed in an enclosure 21 to protect it from its environment. The tanks 2 are generally stored outside the installations.

[0077] The enclosure 21 can, for example, include a steel frame onto which cladding panels are mounted. These panels can be made of a UV-resistant material and include, for example, two layers of aluminum alloy skin and a central layer of polyethylene (typically Dibond®). The frame and panels then have the advantage of being recyclable.

[0078] Optionally, enclosure 12 can also include solar panels to reduce the power consumption of the maintenance device 5.

Claims

DEMANDS 1. Fire protection system (1) by sprinkler network (4) comprising: - spray pipes (3) configured to transport fluid from a tank (2) configured to store a predefined volume of fluid to the sprinkler network (4), the spray pipes (3) and the tank (2) forming a closed fluid circuit; and - a maintenance device (5) connected to the closed fluid circuit and comprising a filter (7) configured to filter the water from the closed fluid circuit, the maintenance device (5) comprising an inlet pipe (11) configured to be mounted on the tank (2) so as to draw fluid and an outlet pipe (12) configured to be connected to the tank (2), near a top of the tank (2), so as to inject the fluid taken from the inlet pipe (11) into the tank (2).

2. Protection system (1) according to claim 1, wherein the filter (7) comprises at least one of a magnetic filter (8) and a sludge trap (9).

3. Protection system (1) according to any one of claims 1 and 2, wherein the inlet pipe (11) has an upstream end mounted on the tank (2) so as to draw the fluid and a downstream end connected to the filter (7), the inlet pipe (11) is: - either mounted on a lower part of the tank (2), near a bottom of the tank (2); - either on an upper part of the tank, near the top, the maintenance device (5) further comprising a self-priming pump (10) so as to draw the fluid.

4. Protection system (1) according to any one of claims 1 to 3, wherein the inlet pipe (11) is configured to be mounted on a tank drain valve (2).

5. Protection system (1) according to any one of claims 1 to 4, wherein the outlet pipe (12) has an upstream end connected to the filter (7) and a downstream end connected to the tank (2), so as to inject the fluid filtered by the filter (7) into the tank (2).

6. Protection system (1) according to claim 5, further comprising a motor-pump unit (6), configured to draw the fluid from the tank (2) and inject it into the spray lines (3), and a discharge line (19) having a first end connected to the motor-pump unit (6) and a second end connected to the outlet line (12) or to the tank (2).

7. Protection system (1) according to any one of claims 5 and 6, further comprising heating means (15) fitted onto the outlet pipe (12), for example a heating cord wound around the outlet pipe (12).

8. Protection system (1) according to claim 7, further comprising a thermal probe (16) configured to measure a temperature of the fluid in the tank (2).

9. Protection system (1) according to any one of claims 6 to 8, wherein the tank (2) further comprises a convection chamber (17) mounted near a top of the tank (2), the outlet pipe (12) being configured to open into the convection chamber (17).

10. Protection system (1) according to any one of claims 1 to 9, wherein the maintenance device (5) further comprises a pump (10) configured to draw the fluid from the tank (2) and circulate it in the maintenance device through the filter (7), between the inlet line (11) and the outlet line (12).

11. Protection assembly comprising a sprinkler network fire protection system (4) according to any one of claims 1 to 10 and a tank (2) fluidly connected to the sprinkler lines (3), the inlet line (11) of the maintenance device (5) being mounted on a lower part of the tank (2) and the outlet line (12) of the maintenance device (5) being connected to the top of the tank (2), the filter of the maintenance device (5) being configured to filter fluid stored in the tank (2).

12. A method for maintaining a fire protection system using a sprinkler network (4) according to claim 11, comprising the following steps: - aspiration (S1) of a volume of fluid from the tank (2); - filtration (S2) of the volume of fluid thus aspirated; and - injection (S5) of the filtered fluid volume into the tank (2).

13. Maintenance method according to claim 12, further comprising a heating step (S4) of the filtered fluid before the injection step (S5).

14. Maintenance method according to claim 13, wherein the heating step (S4) is implemented when the fluid temperature is below a predefined threshold temperature.

15. Maintenance method according to any one of claims 12 to 14, wherein the protection system (1) further comprises a motor-pump unit (6) configured to draw fluid from the tank (2) and inject it into spray lines (3) of the protection system (1) and the maintenance method further comprises the filtration of a cooling fluid from the motor-pump unit (6).

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