EP4414060A1 - Mixing system for fire extinguishing systems - Google Patents

Abstract

The invention relates to a mixing system for fire extinguishing systems for producing an extinguishing agent-extinguishing agent additive mixture (premix) by mixing an extinguishing agent additive, in particular a foam agent, into an extinguishing agent, in particular water, with a motor (1) that can be driven by the extinguishing agent flow, a mixing pump (20) that can be driven by the motor (1), a mixing line and an extinguishing agent additive line. In order to increase the operational reliability of such a mixing system, it is proposed that the wall of the drainage housing (5) of the motor (1) designed as a rotary motor has a through slot (12, 13) for the inlet and/or outlet of the extinguishing agent.

Description

The present invention relates to a mixing system for fire extinguishing systems. A fire extinguishing system in the sense of the present invention is a system having a pump, a pipe system and a foam agent mixing system with which an extinguishing agent can be applied, in particular through nozzles, foam pipes or foam generators. The fire extinguishing system can be a stationary system such as a fire extinguishing system in a tank farm with a permanently mounted so-called monitor, i.e. a large jet pipe, or a permanently mounted sprinkler system in a building. However, it can also be a mobile system on a vehicle or roll-off container.

Such fire extinguishing systems are usually operated using water as an extinguishing agent. However, in many cases it is advantageous to foam the extinguishing agent before applying it to the fire to be fought, so that the applied extinguishing agent forms a long-lasting blanket of extinguishing agent, which can be used to extinguish the fire. To do this, an extinguishing agent additive, in this case a foam agent, is usually first mixed into the extinguishing agent in a certain ratio. The extinguishing agent-extinguishing agent additive mixture (the so-called "premix") is then foamed in a nozzle by supplying air and applied to the fire to be extinguished.

The volume ratio of the extinguishing agent additive to the extinguishing agent, the so-called mixing rate, is typically between 0.5% and 6%.

Another extinguishing agent additive that can be mixed into the extinguishing agent is a wetting agent, which reduces the surface tension of the extinguishing agent, particularly the extinguishing water. This is advantageous, for example, when fighting forest fires because the extinguishing water can then wet larger areas, particularly on the leaves of trees, and can therefore be used more efficiently. Furthermore, the reduced surface tension allows the extinguishing water to penetrate deeper into the forest floor, for example to extinguish deeper embers.

There are also foaming agents that can also be used as wetting agents (if necessary with other mixing rates, in particular with a minimum mixing rate of 0.1%).

The invention is described below in part using the example of water as an extinguishing agent and foam agent as an extinguishing agent additive. However, this is not to be understood as limiting. The invention can also be used when any extinguishing agent additive is added to any extinguishing agent.

To operate the fire extinguishing system with the proportioning system, both the extinguishing agent and the extinguishing agent additive can be provided in an extinguishing agent tank or in an extinguishing agent additive tank or via an extinguishing agent supply line or via an extinguishing agent additive supply line. If the extinguishing agent is provided in an extinguishing agent tank, an extinguishing agent pump is also required, which pumps the extinguishing agent from the extinguishing agent tank, pressurizes it and feeds it to the proportioning system. However, the components just mentioned are not part of the proportioning system itself.

The mixture to be created from the extinguishing agent and the extinguishing agent additive, i.e. the premix, is then passed in the form of a premix stream through a foaming nozzle in the case of a foaming agent as an extinguishing agent additive, in which ambient air is sucked in by the premix stream and mixed with the premix. This activates the foaming agent in the premix and foams the premix so that an extinguishing agent foam emerges from the foaming nozzle and can be applied to the fire.

The air required to foam the foam agent can also be supplied to the premix in the form of compressed air. In the case of such a system that generates compressed air foam, it is referred to as a CAFS system (Compressed Air Foam System).

It is possible to prepare the premix in advance, independently of the fire extinguishing system, but it may then have to be stored for a long time. In many cases, it is therefore more advantageous to prepare the premix immediately before the extinguishing agent is applied to the fire to be fought. For this purpose, the mixing system has a mixing pump through which the extinguishing agent additive can be pumped and mixed with the extinguishing agent.

In the proportioning system considered for the present invention, the proportioning pump is driven by a motor, which in turn is driven by a flow of the extinguishing agent itself.

In the above-mentioned, non-limiting application example of the invention, the proportioning system thus has a water motor that is driven by the extinguishing water flow. For this purpose, the output shaft of the water motor is coupled to the input shaft of the proportioning pump, for example by means of a coupling.

The extinguishing agent additive pumped by the proportioning pump is then fed through an extinguishing agent additive line from the proportioning pump into a proportioning line and mixed there with the extinguishing agent stream to create the premix.

This design of the proportioning system, in which the proportioning pump is driven by the existing extinguishing agent flow, has the advantage that the proportioning pump does not require any external drive energy, particularly electricity, which makes the proportioning system very fail-safe. Furthermore, the delivery rate of the proportioning pump is essentially proportional to the speed of the motor, which in turn is essentially proportional to the flow rate of the extinguishing agent flow. In this way, an essentially constant proportioning rate is automatically achieved without the need for additional control or regulation devices.

The EP 0 647 458 A1 relates to a mixing device for mixing additives into a liquid, in particular for mixing foaming agents into extinguishing agents. In one embodiment, the mixing device has a rotating conveyor device for the foaming agent and a drive device which is driven by a liquid from an extinguishing agent tank. The conveyor device is connected to the drive device in a rotationally fixed manner and is driven by it. The structure of the mixing device therefore basically corresponds to that of the mixing system according to the present application.

The KR 20-0378222 Y1 relates to a mixing system which basically corresponds to the mixing system according to the present application. The mixing pump in this case is a piston pump.

The US$2,347,944 relates to a rotary pump with movable paddles, which has openings for the entry and exit of a fluid into and from a drainage housing.

The US$5,402,569 relates to a rotary pump, which can also have movable paddles, with a drainage housing, here referred to as a cam profile liner, which is composed of two identical plastic halves.

The problem with a proportioning system for fire extinguishing systems with the structure described above is that the components of the proportioning system vibrate during operation and are therefore subjected to mechanical stress, which in extreme cases can lead to cracks and associated leaks. This therefore leads to reduced operational reliability of the proportioning system.

Another problem with such a proportioning system is that certain media used to operate it, particularly extinguishing agent additives with high viscosity, cause high flow resistance in the components of the proportioning system. This means that the media must be put under high pressure in order to overcome the flow resistance mentioned, which in turn places greater strain on the components of the proportioning system and thus impairs the operational reliability of the proportioning system. At the same time, the high flow resistance also reduces the efficiency of the proportioning system.

In addition, such a proportioning system has the problem that individual components, in particular the proportioning pump, can be exposed to an impermissibly high pressure of the extinguishing agent, the extinguishing agent additive and/or the premix and can therefore be damaged or even destroyed. This also endangers the operational safety of the proportioning system.

The invention is therefore based on the object of increasing the operational safety of a proportioning system for fire extinguishing systems with the structure described above.

This object is achieved by a mixing system according to claim 1.

The invention relates to a mixing system for fire extinguishing systems for mixing an extinguishing agent additive, in particular a foam agent, to an extinguishing agent, in particular water.

The mixing system has a motor that can be driven by an extinguishing agent flow, in particular a water motor, with an inlet for supplying the extinguishing agent to the motor, in particular from an extinguishing agent tank or from an extinguishing agent supply line, an outlet for discharging the extinguishing agent from the motor and an output shaft that can be driven by the motor.

The mixing system further comprises a mixing pump for conveying the extinguishing agent additive, in particular a piston pump, with a drive shaft which is coupled to the output shaft of the motor, an inlet for providing the extinguishing agent additive, in particular from an extinguishing agent additive tank or from an extinguishing agent additive supply line, and an outlet for discharging the extinguishing agent additive.

In addition, the mixing system has a mixing line with a first, motor-side end and a second, output-side end, wherein the motor-side end is fluidly connected to the output of the motor.

Furthermore, the admixing system has an extinguishing agent additive line with a first, pump-side end and a second, admixing line-side end, wherein the pump-side end is fluidically connected to the outlet of the admixing pump and the admixing line-side end is fluidically connected to the admixing line at an admixing point.

According to a first aspect, which does not belong to the claimed invention, the motor is a rotary motor in which a rotor is rotatably mounted such that, during its rotation, it strikes an outer wall of a working space of the Motor at least temporarily, wherein an outer wall of the working space in a cross-section perpendicular to a rotation axis of the rotor at least partially has substantially the shape of a logarithmic spiral.

The rotary motor is preferably a water motor that works according to the displacement principle, in which the rotor is made up of several parts and has a rotor body and several radially movable blades (so-called paddles). The radial displacement of the paddles with each revolution of the motor results in a back and forth movement of the paddles at a high frequency. In conventional water motors, this can lead to vibrations and to the water motor running unevenly. This can place mechanical stress on the water motor, which has a negative effect on its service life and operational reliability.

According to the first aspect, it has been shown that the smooth running of the water motor can be improved if the radially outer ends of the paddles describe a path in the form of a logarithmic spiral at least in sections during their movement.

wobei ϕ der Drehwinkel eines Punktes auf der Spirale und r(<p) der zugehörige Radius des Punktes ist. Weiterhin ist der Parameter k die Steigung der Spirale und a ein weiterer Skalierungsfaktor.In the usual mathematical sense, a logarithmic spiral is a spiral in which the distance from its center changes by the same factor with each revolution of the spiral. A logarithmic spiral can be represented in polar coordinate form by the equation $$r\left(\varphi \right)={\mathit{ae}}^{\mathit{k\varphi }},$$

where ϕ is the angle of rotation of a point on the spiral and r(<p) is the corresponding radius of the point. Furthermore, the parameter k is the slope of the spiral and a is another scaling factor.

Since the path of the radially outer ends of the paddles is predetermined by their contact with the outer wall of the working space of the water motor, according to the invention the cross section of the working space perpendicular to a rotation axis of the rotor is designed, at least in sections, essentially in the form of a logarithmic spiral.

The lower mechanical load on the water motor improves the operational reliability of the mixing system.

According to the invention, the motor is a rotary motor in which a rotor is rotatably mounted in a drainage housing.

According to the invention, the wall of the drainage housing has at least one, in particular at least one through slot extending substantially in a plane perpendicular to a rotation axis of the rotor, for the inlet of the extinguishing agent into the drainage housing and/or for the outlet of the extinguishing agent from the drainage housing.

In order for the extinguishing agent to enter the drainage housing to drive the rotor there and to exit the drainage housing again, the wall of the drainage housing must not be closed, but must have at least one opening through which the extinguishing agent can flow.

For this purpose, the invention provides at least one through slot in the wall of the drainage housing. This preferably runs essentially in a plane perpendicular to a rotation axis of the rotor in order to cause the lowest possible flow resistance for the extinguishing agent. Furthermore, two, three or more through slots, in particular a plurality of through slots, are preferably arranged in the wall of the drainage housing.

A through slot is to be understood in the usual sense as an elongated, in particular straight opening, which completely penetrates a surface, in this case the wall of the drainage housing, and thus creates an opening from one side of the surface to the other side of the surface.

In particular, through-slots in the wall of the drainage housing cause a lower flow resistance for the extinguishing agent than, for example, through-holes in the wall of the drainage housing, as used in conventional engines with the structure considered here.

The provision of through-slots in the wall of the drainage housing results in a reduction in the pressure loss of the extinguishing agent when the motor is in operation and a reduction in wear on the motor. This also increases the operational reliability of the proportioning system.

According to a third aspect, which does not belong to the claimed invention, the proportioning pump is a piston pump.

According to the third aspect, the inlet of the proportioning pump is arranged on the proportioning pump in such a way that the extinguishing agent additive can flow into the proportioning pump essentially parallel to the direction of movement of at least one of the, preferably all, pistons of the proportioning pump.

This design measure achieves improved suction characteristics, particularly for extinguishing agent additives with high viscosity, compared to conventional angled connections at the inlet of the proportioning pump, which often have sharp edges on the inside. In particular, the extinguishing agent additive does not have to be diverted when entering the proportioning pump before it flows into the cylinders belonging to the pistons. This reduces the flow resistance that the extinguishing agent additive has to face at the inlet of the proportioning pump. and the resulting pressure loss is significantly reduced. In this way, the operational reliability and efficiency of the proportioning system are improved.

According to a fourth aspect, which is not part of the claimed invention, the proportioning pump has a relief valve, in particular integrated in its pump cover. This protects the proportioning pump from excessive pressure of the extinguishing agent additive, which can occur, for example, due to incorrect feeding from an extinguishing agent additive tank or from an extinguishing agent additive supply line. By integrating the relief valve into the proportioning pump, the installation space of the proportioning system is also reduced, in particular compared to arranging the relief valve outside the proportioning pump.

Fig.1

eine Prinzipskizze eines Wassermotors eines erfindungsgemäßen Zumischsystems in einem Querschnitt senkrecht zur Rotationsachse des Rotors des Wassermotors;

Fig. 2

einen schematischen Querschnitt durch eine Zumischpumpe eines Zumischsystems gemäß dem dritten und dem vierten Aspekt.

Further advantages, features and possible applications of the present invention will become apparent from the following description in conjunction with the figures. In the figures:

Fig.1

a schematic diagram of a water motor of an inventive mixing system in a cross-section perpendicular to the axis of rotation of the rotor of the water motor;

Fig.2

a schematic cross-section through a mixing pump of a mixing system according to the third and fourth aspects.

The water motor 1 of a mixing system according to the first aspect not belonging to the claimed invention and according to the invention is in the embodiment according to Fig.1 a rotary motor operating according to the displacement principle. The water motor 1 has a housing 2 with a through-opening which connects an inlet 3 with a working chamber 10 and an outlet 4. In this way, the extinguishing water can from its inlet 3 through the working chamber 10 in the direction of the outlet 4.

Between the inlet 3 and the outlet 4, a tubular drainage housing 5, the outside of which has a cylindrical shape, is arranged in a rotationally fixed manner relative to the housing 2. The axis of the cylinder runs perpendicular to the flow direction of the water motor 1 (in Fig.1 perpendicular to the plane of the sheet). Through-slots 12, 13 are provided in the wall of the drainage housing 5, through which the extinguishing water can flow.

A rotor 9 with a cylindrical rotor body 8 is arranged inside the drainage housing 5 and is mounted so as to be rotatable about a rotation axis. The rotation axis of the rotor 9 runs parallel to the axis of the drainage housing 5, but is offset from it, so that the rotor 9 is arranged eccentrically in the drainage housing 5.

The sickle-shaped cavity remaining between the outer wall of the rotor body 8 and the inner wall 11 of the drainage housing 5 forms the working space 10 of the water motor 1. In particular, the outer wall of the rotor body 8 forms the inner wall of the working space 10 and the inner wall 11 of the drainage housing 5 forms the outer wall of the working space 10. In an area where the outer wall of the rotor body 8 touches the inner wall 11 of the drainage housing 5, the inner wall 11 of the drainage housing 5 is slightly "bulged" radially outwards in a circular arc shape in cross-section (in Fig.1 at the upper edge of the rotor body 8).

The rotor 9 also has two wing-shaped paddles 6, 7, which are inserted into radial slots in the rotor body 8. The paddles 6, 7 are radially displaceable within the rotor body 8 and can project radially outward beyond it. The paddles 6, 7 also have recesses (not shown) in their respective middle parts, which ensure that they do not collide with one another at their intersection point on the axis of rotation of the rotor 9.

The radial extension of the paddles 6, 7 is dimensioned such that each paddle 6, 7 approximately touches the inner wall 11 of the drainage housing 5 at both ends, whereby the paddles 6, 7 are still freely movable when the rotor 9 rotates. When the rotor 9 rotates, the paddles 6, 7 are periodically pushed back and forth due to the eccentric arrangement of the rotor 9 in the working space 10. The paddles 6, 7 form chambers of different volumes in the working space 10 with the outer wall of the rotor body 8 and the inner wall 11 of the drainage housing 5.

If the water motor 1 is flowed through by the extinguishing water, the rotor 9 is set in rotation by the extinguishing water. In this way, an output shaft (not shown) of the water motor 1 connected to the rotor 9 is also set in rotation in order to drive a mixing pump.

It has been shown that the water motor 1 runs unsteadily if the inner side 11 of the drainage housing 5 also has a cylindrical shape - apart from the "bulge" described above. In this case, the sharp, axially running edges that form at the transition between the cylindrical shape and the aforementioned bulge lead to a shock every time one end of a paddle 6, 7 is passed over. These shocks cause vibrations and unsteady running of the water motor 1, particularly at higher speeds of the water motor 1.

The inner side 11 of the drainage housing 5 is therefore divided into individual sections, which Fig.1 shown in dashed lines, are designed in the form of a logarithmic spiral. In this way, the sharp edges mentioned on the inside 11 of the drainage housing 5 and thus the impacts on the ends of the paddles 6, 7 are avoided, whereby the operation of the water motor 1 becomes considerably smoother.

In Fig.2 a proportioning pump 20 of a proportioning system according to the third aspect not belonging to the claimed invention is shown. The proportioning pump 20 has the form of a piston pump with three pistons 24, 25, 26, which move up and down parallel to one another in the direction of the double arrows 27, 28, 29 in a respective cylinder (not shown) of the proportioning pump 20. The pistons 24, 25, 26 and the associated cylinders are accommodated in a housing 21 of the proportioning pump 20.

The proportioning pump 20 has an inlet 22 through which an extinguishing agent additive can be supplied to it. The inflow of the extinguishing agent additive takes place in the direction of arrow 23 and thus parallel to the direction of movement 27, 28, 29 of the pistons 24, 25, 26.

This ensures that the extinguishing agent additive is not diverted from the point of entry into the proportioning pump 20 at its inlet 22 to the point of entry into the cylinders, whereby the extinguishing agent additive is only exposed to a low flow resistance. This contributes to an improvement in the efficiency of the proportioning pump 20 and thus of the entire proportioning system, particularly in the case of highly viscous extinguishing agent additives.

Fig.2 also represents a proportioning pump 20 of a proportioning system according to the fourth aspect not belonging to the claimed invention. Behind the inlet 22 of the proportioning pump 20 and before the cylinders with the pistons 24, 25, 26 there is a relief valve 30 which closes when the pressure of the extinguishing agent additive flowing into the proportioning pump 20 is too high and thus protects the proportioning pump 20 from damage or even destruction. The relief valve 30 is integrated in the housing 21 of the proportioning pump 20 and in particular in its pump cover and therefore does not require any additional installation space.

Claims (1)

Mixing system for fire extinguishing systems for producing an extinguishing agent-extinguishing agent additive mixture (premix) by mixing an extinguishing agent additive, in particular a foam agent, to an extinguishing agent, in particular water, with - a motor (1) which can be driven by a flow of extinguishing agent, in particular a water motor, with an inlet (3) for supplying the extinguishing agent to the motor (1), in particular from an extinguishing agent tank or from an extinguishing agent supply line, an outlet (4) for discharging the extinguishing agent from the motor (1) and an output shaft which can be driven by the motor (1), - a mixing pump (20) for conveying the extinguishing agent additive, in particular a piston pump, with a drive shaft which is coupled to the output shaft of the motor (1), an inlet (22) for providing the extinguishing agent additive, in particular from an extinguishing agent additive tank or from an extinguishing agent additive supply line, and an outlet for discharging the extinguishing agent additive, - a mixing line with a first, motor-side end and a second, output-side end, the motor-side end being fluidly connected to the output (4) of the motor (1), - an extinguishing agent additive line with a first, pump-side end and a second, mixing line-side end, wherein the pump-side end is fluidically connected to the outlet of the mixing pump (20) and the mixing line-side end is fluidically connected to the mixing line at a mixing point, - wherein the motor (1) is a rotary motor in which a rotor (9) is rotatably mounted in a drainage housing (5), characterized in that
the wall of the drainage housing (5) has at least one through slot (12, 13), in particular at least one substantially extending in a plane perpendicular to a rotation axis of the rotor (9), for the inlet of the extinguishing agent into the drainage housing (5) and/or for the outlet of the extinguishing agent from the drainage housing (5).

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