WO2011141361A1

WO2011141361A1 - Automatic fire extinguishing system

Info

Publication number: WO2011141361A1
Application number: PCT/EP2011/057267
Authority: WO
Inventors: Karl Bermes; Frank Felten; Christoph Müller
Original assignee: Fiwarec Valves & Regulators Gmbh & Co. Kg
Priority date: 2010-05-11
Filing date: 2011-05-06
Publication date: 2011-11-17
Also published as: DE102010028857B4; DE102010028857A1

Abstract

The invention relates to an automatic fire extinguishing system, comprising a pressure vessel (2) for storing a fire extinguishing medium, a sensor line (5) connected to the pressure vessel (2) for automatically detecting a fire for initiating an extinguishing sequence, an extinguishing line (6) connected to the pressure vessel (2) for discharging the fire extinguishing medium during the extinguishing sequence, a pressure sensor (12) having a pressurized connection to the pressure vessel (2) for initiating a switch signal as a function of a system pressure (p_sys), and a control unit (38) having a signaling connection to the pressure sensor (12) for controlling assemblies, wherein the pressure sensor (12) comprises a housing (13) having an interior (22) comprising a longitudinal axis (14) and a connection opening (20) for connecting the pressure sensor (12) to the system pressure (p_sys), a piston (23) disposed displaceably along the longitudinal axis (14) in the interior (22) of the housing (12), and a switch unit (37) that can be initiated by the piston (23) for initiating a switch signal.

Description

Automatic fire extinguishing system

The invention relates to an automatic fire extinguishing system. Such fire extinguishing systems are known by public prior use for some time. Such fire extinguishing systems include a pressure vessel with fire extinguishing medium such as N ₂ , a connected to the pressure vessel sensor line for automatically detecting a fire for triggering an extinguishing operation and connected to the pressure vessel extinguishing pipe for dispensing the fire extinguishing medium during the deletion process. A pressure switch is used to monitor a system pressure prevailing in the fire extinguishing system and a signal to be triggered as a function of the system pressure. The pressure switch is used, for example, to initiate a signal at a drop in system pressure below a critical threshold, which is equivalent to a fire, such that certain units or other devices are turned off.

From the field of hydraulic and pneumatic systems, pressure switches are known, which are in principle suitable for such signaling. However, these pressure switches can have leaks that can not be compensated in the closed system of the automatic fire extinguishing system and thus cause pressure losses in the automatic fire extinguishing system. Such types of pressure switch are for the application due to the unreached requirements regarding the

Tightness for automatic fire extinguishing systems not suitable because the functional reliability of the fire extinguishing system is impaired overall. The invention has for its object to make such an inexpensive automatic fire extinguishing system with pressure monitoring that at the same time the reliability is guaranteed. The object is solved by the features of claim 1. The essence of the invention is to provide an automatic fire extinguishing system with a pressure switch such that it triggers a switching signal in response to a system pressure. For this purpose, the pressure switch is in pressure communication with a pressure vessel for storing a fire extinguishing medium. Connected to the pressure vessel is a sensor line for automatic detection of a fire for triggering a deletion. In particular, the sensor line is designed such that in a fire, the line opens, in particular bursts, and thus initiated via a attachable to the pressure vessel valve and also connected to the pressure vessel extinguishing a release of the fire extinguishing medium. Through the opening of the sensor line, the system pressure in the sensor line itself and also in the pressure vessel decreases abruptly. Because of this pressure drop of the system pressure of the pressure switch triggers a corresponding switching signal, which can be used via a standing in signal communication with the pressure switch control unit for controlling aggregates, in particular for switching off the same. Acoustic or optical signaling without shutdown function is also possible. The pressure switch comprises a housing with an interior space and a longitudinal axis and a connection opening for connecting the pressure switch to the system pressure. The pressure switch may preferably be connected directly to the sensor line, but also to the pressure vessel. An application in fire extinguishing systems without pneumatic sensor line is also possible. In the interior of the housing, a piston is slidably disposed along the longitudinal axis, which can trigger a switching unit to trigger the switching signal. For this purpose, the interior may be divided by the piston into a system pressure chamber under system pressure and into a fluid-tight separate reference pressure chamber. The switching unit may have a permanent magnet attached to the piston and a stationary mounted on the housing reed switch. With such a design of the switching unit, the switching signal is triggered as a function of the distance of the displaceable with the piston in the housing permanent magnet to the stationary reed switch, wherein the distance of the permanent magnet from the reed switch in response to the prevailing system pressure adjusts itself. Due to the fact that the system pressure chamber and the reference pressure chamber can be fluid-tightly separated from one another, the piston in the interior space can be displaced in such a way that there is an equilibrium of forces in the pressure switch in the pressure switch, so that both in the system pressure Chamber as well as in the reference pressure chamber equal pressures. In such a position, the piston is completely pressure compensated so that even a source of leakage does not interfere with the function of the automatic fire extinguishing system due to the permanent pressure equalization between the system pressure chamber and the reference pressure chamber. Upon initiation of the fire by the sensor line causes the drop in system pressure displacement of the piston as a result of the force imbalance between system pressure and reference pressure chamber. As soon as the permanent magnet displaced by the piston reaches a definable distance to the reed switch, a switching

Signal triggered. Such a pressure switch works without contact and is therefore particularly suitable for monitoring pressure-dependent positions in the closed system. Furthermore, the demands on tightness are fulfilled by the system according to the invention. The func- Safety on fire extinguishing system is guaranteed and would not be affected even if leakage occurs, for example, in the pressure switch. Further advantageous embodiments of the invention will become apparent from the dependent claims.

Additional features and details of the invention will become apparent from the following description of an embodiment with reference to the drawing. Show it:

1 is a side view of an automatic fire extinguishing system,

2 is an enlarged view of a pressure switch according to FIG. 1,

Fig. 3 is a longitudinal section along the section line III-III in Fig. 2 in a spaced from an eed switch position of a piston and Fig. 4 is a Fig. 3 corresponding representation with a reed switch adjacent arrangement of the piston.

An automatic fire extinguishing system 1 shown in FIG. 1 comprises a pressure vessel 2 for storing a fire extinguishing medium, in particular nitrogen (N ₂ ). On the pressure vessel 2, a valve 3 is attached to which a pressure gauge 4 is mounted. Connected via the valve 3 to the pressure vessel 2 are a sensor line 5 for the automatic detection of a fire for triggering an extinguishing process and an extinguishing line 6 for dispensing the fire extinguishing medium during the extinguishing Process. The extinguishing line 6 has a plurality of extinguishing nozzles 7 for dispensing the fire extinguishing medium. At a connected to the valve 3 opposite end of the discharge line 6 is a closing plug 8 for fluid-tight closing of the discharge line 6 is provided. It is also possible to use a further extinguishing nozzle 7 instead of the closing plug 8.

The sensor line 5 is laid in the region of one or more objects to be protected and acted upon by the pressure vessel 2 via the valve 3 with a system pressure, which can be reduced in particular against an internal pressure, under which the fire extinguishing medium is stored in the pressure vessel 2. A pressure reduction is required, for example, when the container pressure does not correspond to the required operating pressure for the sensor line 5. The sensor line 5 is designed as a plastic hose and branched by means of a T-connector 9. Depending on the design of the sensor conduit to be designed, various connectors can be used, which are known per se, for example for hose connections, to produce any desired lengths and / or configurations of the sensor conduit 5. One end of the sensor line 5 is sealed fluid-tight by a closure element 10. Also connected to the sensor line 5 via a line end connection element 1 1, is a pressure switch 12 for triggering a switching signal as a function of the system pressure in the sensor line 5. The pressure switch 12 may also be connected directly to the fire extinguishing system 1 to the container pressure monitor..

In the following, the pressure switch 12 will be described in detail with reference to FIGS. 2 to 4. In the cited figures, the pressure switch 12 is decoupled from the sensor line 5 and shown enlarged. The pressure switch 12 has a housing 13 with a longitudinal axis 14. Opposite the position in Fig. 1, the pressure switch 12 is rotated in Fig. 2 about the longitudinal axis 14 by 90 °. The housing 13 is designed in two parts with a lower housing part 15 and an upper housing part 16 screwed thereto. Due to the two-part design of the housing 13, the production and, above all, the assembly of the pressure switch 12 are facilitated. By screwing the two housing parts 15, 16 in particular a disassembly example, for maintenance purposes of the pressure switch 12 is possible. An interior 22 surrounded by the two housing parts 15, 16 is sealed at a connection point by a circumferential seal 17 from the environment. As a result, leaks of the pressure switch 12 are avoided. The lower housing part 15 has a connection piece 18 for connection to the sensor line 5 acted upon by the system pressure p _sys via the line end connection element 11 or to the pressure container. On an outer wall of the lower housing part 15, a hexagonal profile 19 is integrally formed to screw the lower housing part 15 with a suitable tool with the upper housing part 16. The connecting piece 18 has a connection opening 20, with which the pressure switch 12 is connected to the sensor line 5 and thus to the system pressure p _sys . From the arranged on the lower housing part 15 connecting port 20, a pressure channel 21 leads to the interior 22 of the housing 13. The interior 22 and the pressure channel 21 are arranged concentrically to the longitudinal axis 14. The interior 22 is designed substantially cylindrical. In the interior 22, a piston 23 is arranged, which is arranged displaceably along the longitudinal axis 14 in the inner space 22 of the housing 13. The piston 23 divides the inner space 22 into a system pressure chamber 24 under system pressure p _sys and a reference pressure chamber 25 separated therefrom in a fluid-tight manner. The system pressure chamber 24 is above the Pressure channel 21 connected to the system pressure p _sys . The reference pressure chamber 25 is hermetically sealed by the upper housing part 16 of the housing 13 on the one hand and by the piston 23 sealed in a fluid-tight manner with respect to the inner space 22 by means of a piston seal 26. The piston 23 has an upper piston part 27 and a lower piston part 28 screwed to the upper piston part 27. The upper piston part 27 faces the reference pressure chamber 25 and the lower piston part 28 faces the system pressure chamber 24. The piston seal 26 is arranged in a circumferential piston groove 29 provided on the upper piston part 27 between the piston 23 and an inner wall 30 of the inner space 22. The piston 23 is arranged concentrically to the longitudinal axis 14 in the inner space 22. To screw the lower piston part 28 into the upper piston part 27, the lower piston part 28 has a hexagon socket 31. The hexagon socket 31 is arranged correspondingly concentric to the longitudinal axis 14 and has a size such that the hexagon socket 31 can be actuated from outside the pressure switch 12 via the pressure channel 21 by means of a tool provided for this purpose. The two piston parts 27, 28 are sealed by means of a piston part seal 32. This avoids that medium from the interior 22 penetrates into a cavity 33 formed by the two piston parts 27, 28 and thus corrosion of a permanent magnet 34 arranged in the cavity is avoided. The cavity 33 is substantially cylindrically shaped. The permanent magnet 34 is disposed in the cavity 33 of the piston 23 so as to be held between the upper piston part 27 and the lower piston part 28. Accordingly, the permanent magnet 34 is arranged concentrically to the longitudinal axis 14. The permanent magnet 34 is aligned with its poles along the longitudinal axis 14, wherein in the embodiment shown, the south pole 35 of the upper housing part 16 and thus the reference pressure chamber 25th is facing. It is also possible to align the permanent magnet 34 along the longitudinal axis 14 such that the south pole 35 faces away from the reference pressure chamber 25 and thus faces the north pole of the reference pressure chamber 25. Furthermore, an arrangement of the magnet 34 is possible such that the poles transversely and in particular perpendicular to

Longitudinal axis 14 are aligned. In a vertical arrangement of a connecting line of the two poles to the longitudinal axis 14, the poles are arranged at the same distance from the reference pressure chamber 25. A switching unit 37 for triggering a switching signal comprises the permanent magnet 34 fixed to the piston 23 and the reed switch 36 fixedly mounted on the housing 13. The reed switch 36 faces the reference pressure chamber 25 in the housing 13. In the upper housing part 16 of the housing 13, a reed switch 36 is fixedly mounted. The reed switch 36 has in known manner two reed contacts not shown, each having a semicircular magnetic field such that when approaching the permanent magnet 34, the contacts are closed or opened and thus a switching signal from the reed Switch 36 is triggered. The contacts are closed or opened as long as the permanent magnet 34 is within the semicircular surface. As soon as the permanent magnet 34 leaves the semicircular surface, open or close the reed contacts. The boundary of the semicircular region at which the permanent magnet 34 leaves the switching range of the reed switch 36 is referred to as a switching distance and applies a

Switching position of the piston 23 fixed. The switching unit 37 is set such that upon reaching a defined, in particular an individually adjustable, system pressure p _sys , def in the interior 22 of the housing 13, the switching signal is triggered. With the pressure switch 12 in signal connection is a control unit 38 for controlling various units, other devices and / or an acoustic or an optical signaling. In particular, this means that after the triggering of the deletion process, for example, the objects or other devices to be protected can be shut off selectively and quickly. For the signal connection of the switching unit 37 with the control unit 38, a switching line 39 is provided. To protect the switching line 39, this is brought out of the housing 13 by means of a protective connection 40 which can be screwed into the housing 13.

The permanent magnet 34 is made of Sm2Col7 according to the embodiment shown and has a cylindrical basic shape with a diameter of 4 mm and a height of 4 mm. There are also other materials for the production of the permanent magnet 34 possible. The size of the magnet 34 results essentially from the design of the piston 23 and can be varied accordingly.

In principle, it is also conceivable to equip the pressure switch with an alternative switching unit. For example, small electrical

Switches are used, which are operated mechanically via a piston or via a membrane, which are subjected to system pressure. However, such switches have problems in terms of tightness. There are also manometer with integrated mechanical contact as a switch conceivable, which is coupled to a pointer movement of a display of the pressure gauge and thus produces or interrupts switch contacts at intended pressure points. Also possible are pressure sensors with strain gauges, which require an additional power supply to measure a system pressure. In the illustrated switching Unit 37 with the eed switch 36 will only generate current flow when the reed contacts are closed. Another alternative is Hall sensors in which an external power supply is always required to measure the system pressure.

It is also possible to provide a plurality of pressure switches 12 on the automatic fire extinguishing system 1. In particular, this makes it possible to reduce the maximum distance from a fire initiation point, at which the sensor line 5 bursts, to a corresponding pressure switch 12 and thus to achieve a faster triggering of the extinguishing process. Moreover, it is also possible to connect the pressure switch 12 directly to the valve 3 of the pressure vessel 2 or to integrate it into the valve 2. Upon integration of the pressure switch 12 into the valve 2, the number of interfaces and parts of the overall arrangement is reduced, resulting in an overall improved tightness of the system.

In the following, the operation of the pressure switch 12 is explained in more detail with reference to FIGS. 3 and 4. The piston 23 is arranged in a lowermost position as shown in FIG. 3 and lies with the lower one

Piston portion 28 on a shoulder of the lower housing part 15 on. In this case, the interior 22 includes only the reference pressure chamber 25. The volume of the system pressure chamber 24 tends toward zero. The position of the piston 23 results from the equilibrium of forces of a force acting from the force acting on a lower side 41 of the lower piston part 28 system pressure p _sys force and a force counteracting this reference force due to a reference pressure p _ref in the reference pressure chamber 25 acts on an upper side 42 of the upper piston part 27. In the illustration in FIG. 3, the pressure switch 12 is not connected to the Sensor line 5 is connected, so that the pressure channel 21 is subjected to atmospheric pressure p _atm. The reference pressure p _re is greater than or equal to the atmospheric pressure p _Atm , so that the piston 23 is moved due to the force balance acting on it in the lower position shown.

Once the pressure switch 12 is connected to the at system pressure p _sys sensor line 5 acts on the pressure conduit 21 to the underside 41 of the piston 23, the system pressure p _sys. The reference pressure p _re is selected such that the system pressure p _sys pushes the piston 23 in an upper, shown in FIG. 4 position. Due to the fact that the reference pressure chamber 25 is hermetically sealed, the medium in the reference pressure chamber 25 is compressed due to the displacement of the piston 23 and the reference pressure p _re in the reference pressure chamber 24 increases until the reference pressure p _{re is the} same the system pressure p _sys . In this state shown in Fig. 4, the interior 22 is in a pressure equilibrium.

With the piston 23 and the permanent magnet 34 along the longitudinal axis 14 is displaced upward in the direction of the reed switch 36. In this case, the magnetic field of the reed contacts is designed such that the permanent magnet 34 is in the upper position shown within the relevant semicircular switching range and thus above a switching distance, so that the reed contacts are closed.

As soon as a fire occurs and a sensor line bursts, the system pressure psys abruptly drops and due to the changed equilibrium of forces in the interior 22 of the pressure switch 12, the piston 23, starting from the upper position shown in FIG Move longitudinal axis 14 downwards. As soon as the piston 23 with the permanent magnet 34 leaves a switching region of the reed contacts, the reed contacts are opened and a switching signal is triggered accordingly. The positioning of the piston 23 in the inner space 22 is determined by the forces acting on the piston 23 equilibrium. Thus, for example, by increasing the reference pressure p _re f can be achieved that the balance of forces between the system pressure p _sys and the increased in consequence of the compression reference pressure p _re f in the reference pressure chamber 25 in a lower position opposite to that shown in Fig. 4 of the piston 23 is reached. In any case, the reference pressure p _re f is to be set such that the equilibrium reference pressure arising as a result of the equilibrium of forces in the reference pressure chamber 25 _{corresponds to} a defined system pressure p _syS; def corresponds to such that the piston 23 is spaced a maximum of the switching distance to the reed contacts when the piston 23 with the defined system pressure p _syS; def is acted upon.

Claims

claims

1. Automatic fire extinguishing system comprising

a. a pressure vessel (2) for storing a fire extinguishing medium, b. a sensor line (5) connected to the pressure vessel (2) for the automatic detection of a fire event for triggering an extinguishing process,

c. an extinguishing pipe (6) connected to the pressure vessel (2) for discharging the fire extinguishing medium during the extinguishing operation, d. one with the pressure vessel (2) in pressure communication

Pressure switch (12) for triggering a switching signal as a function of a system pressure (p _sys ) and

e. one in communication with the pressure switch (12)

Control unit (38) for controlling aggregates,

wherein the pressure switch (12) comprises

f. a housing (13) with

i. a longitudinal axis (14) having interior (22) and ii. a connection opening (20) for connecting the pressure switch (12) to the system pressure (p _sys ),

G. one in the interior (22) of the housing (12) along the longitudinal

Axis (14) slidably disposed piston (23) and

H. a triggerable by the piston (23) switching unit (37) for triggering a switching signal.

2. fire extinguishing system according to claim 1, characterized in that the interior (22) by the piston (23) in a system pressure under pressure (p _sys ) located system pressure chamber (24) and in a fluid-tightly separate reference pressure chamber ( 25) is divided.

3. fire extinguishing system according to claim 2, characterized in that the reference pressure chamber (25) through the housing (13) and the piston (23) is hermetically sealed.

4. Fire extinguishing system according to one of the preceding claims, characterized in that the switching unit (37) has a fixed to the piston (23) permanent magnet (34) and one on the housing (13) fixedly mounted reed switch (36).

5. fire extinguishing system according to claims 2 and 4, characterized in that the reed switch (36) facing the reference pressure chamber (25).

6. Fire extinguishing system according to one of claims 4 or 5, character- ized in that the poles of the permanent magnet (34) along the

Longitudinal axis (14) are aligned and in particular the south pole (35) facing the reed switch (36).

7. Fire extinguishing system according to one of the preceding claims, characterized in that the switching unit (37) triggers a switching signal upon reaching a switching position of the piston (23).

8. fire extinguishing system according to claim 7, characterized by the

Switching unit (37) such that upon reaching a defined, in particular individually adjustable, system pressure (p _sys , def) in the interior (22), the switching signal is triggered.

9. Fire extinguishing system according to claim 7 or 8, characterized by a switching distance as the switching position of the piston.

10. Fire extinguishing system according to one of the preceding claims, characterized by a switching line (39) for signal connection of the switching unit (37) with the control unit (38).

1 1. Fire extinguishing system according to one of the preceding claims, characterized in that the housing (13) has an upper housing part (16) and one with the upper housing part (16) connected, in particular screwed, lower housing part (15) for connection to the system pressure (p _sys ).

12. Fire extinguishing system according to claim 1 1, characterized in that the connection of the upper housing part (16) with the lower housing part (15) by means of a seal (17) is sealed fluid-tight.

13. Fire extinguishing system according to one of the preceding claims, characterized in that the piston (23) has an upper piston part (27) and one with the upper piston part (27) connected, in particular screwed, lower piston part (28) ,

14. Fire extinguishing system according to claims 4 and 13, characterized in that the permanent magnet (34) is held in the piston (23) between the upper piston part (27) and the lower piston part (28).