METHOD FOR THE MANUFACTURE OF FIRE-FIGHTING AGENT, MIXING DEVICE AND EMERGENCY VEHICLE

Description

[0001] The invention relates to an emergency vehicle with a mixing device according to the preamble of independent claim 1 and a method for producing extinguishing agent for fire fighting by means of a mixing device on board an emergency vehicle according to the preamble of independent claim 1, wherein extinguishing agent is produced by admixing at least one additive to extinguishing water.

[0002] Such emergency vehicles and procedures have been known from the state of the art for some time.

[0003] For example, DE 30 38 334 A1 discloses a device for firefighting vehicles for admixing a foam- or film-forming additive to the extinguishing water flow. The device has an extinguishing water tank from which extinguishing water is drawn by means of an extinguishing water pump. The extinguishing water pump is driven by the vehicle's engine or, alternatively, a separate drive motor. Furthermore, the device comprises an additive tank from which additive, for example, foam, is drawn by means of an additive pump. The additive pump is driven by a speed-controlled drive motor. The additive line and the extinguishing water line merge at a junction point to form an extinguishing agent line. The extinguishing water is thus mixed with a specific amount of additive. The extinguishing agent line terminates at discharge points, for example, nozzles of fire hoses.To ensure a consistently constant mixing ratio between extinguishing water and additive, a flow meter connected to a measuring and control device is installed in the extinguishing water line upstream of the junction point. The measuring and control device allows the target value for the mixing ratio between extinguishing water and additive to be set. Based on this target value and the actual water flow rate resulting from the flow meter's measurement signal, the required additive flow rate or the corresponding speed of the additive pump is calculated. A corresponding control signal is then sent to the additive pump drive unit connected to a control output of the measuring and control device.

[0004] DE 10 2005 057 200 A1 discloses a firefighting vehicle with a motor-driven water pump in a mixing device for producing a liquid mixture with the addition of at least one additive to the extinguishing water. The motor for driving the water pump is the vehicle engine of the firefighting vehicle, with a transmission mechanism coupled to the motor having a switchable clutch for connecting or disconnecting an additive pump that draws additive from an additive storage tank. The flow rate of the pumped water in the water line is determined using a flow measuring device, with the detected measurement signal forming an input variable for an electronic control system. This electronic control system is equipped with a device for adjusting the admixing rate.

[0005] US 2014 / 0262354 A1 discloses a firefighting system comprising a mixing device for mixing extinguishing water and an additive in the form of foam to form an extinguishing agent and feeding it to nozzles. An additive pump is provided, which is driven by an electric drive in the form of a servo motor controlled by a controller. The controller has a controller with a DSP (digital signal processor) and a CPU.

[0006] The object of the invention is to provide an emergency vehicle and a method for producing extinguishing agents for fire fighting by adding at least one additive to extinguishing water, which can be constructed simply and operated cost-effectively and yet reliably.

[0007] This object is achieved by an emergency vehicle having the features of independent claim 1 and a method for producing extinguishing agent for fire fighting by admixing at least one additive to extinguishing water having the features of independent claim 7.

[0008] The emergency vehicle according to the invention, in particular a fire service vehicle, has an on-board electrical system for the electrical supply of electrical consumers on board the emergency vehicle and has a mixing device for producing extinguishing agent for firefighting by admixing at least one additive to extinguishing water, which has an extinguishing water pump that can suck in extinguishing water from an extinguishing water source via at least one suction line and can supply it to at least one pressure outlet via at least one pressure line, wherein an additive pump is also provided that can suck in additive from an additive source via at least one additive suction line and can supply it to a mixing point via at least one additive pressure line, where additive can be mixed with the extinguishing water at a pre-adjustable or pre-set mixing rate, wherein the additive pump is drivable by means of an electric additive pump drive that can be controlled via an actuator,wherein a flow measuring device arranged in the flow direction upstream of the admixing point is connected to the pressure line for measuring the actual flow rate of the extinguishing water, and wherein the mixing device has a control / regulation device coupled to the actuator for determining the required admixing rate based on the measured actual flow rate, wherein the mixing device can be or is coupled to an on-board electrical system of an emergency vehicle and the voltage supply of the electric additive pump drive is provided via a voltage source of the on-board electrical system.

[0009] The emergency vehicle according to the invention is characterized in that the actuator is designed as a frequency converter for varying a speed of the electric additive pump drive.

[0010] The voltage source is conveniently coupled to the actuator.

[0011] In a particularly preferred manner, the voltage source is designed as a generator.

[0012] Particularly preferably, the generator can be driven by a vehicle engine of the emergency vehicle.

[0013] In a particularly preferred manner, the generator is designed as a direct voltage generator.

[0014] The generator is expediently designed as a low-voltage generator to generate a low voltage in the range of 30V to 60V.

[0015] Most preferably, the low-voltage generator is a 48V generator.

[0016] In a further development of the invention, the additive pump is designed as a piston diaphragm pump. Piston diaphragm pumps deliver a consistently large amount of additive per stroke, so that the amount of additive to be added can be adjusted relatively precisely by varying the speed and thus the number of strokes within a certain period of time, for example, one minute. However, other pump types can also be used.

[0017] The fire extinguishing water pump is conveniently designed as a centrifugal fire pump. The centrifugal fire pump is conveniently coupled to and driven by a vehicle engine.

[0018] The method according to the invention for producing extinguishing agent for fire fighting by means of a mixing device on board an emergency vehicle according to one of claims 1 to 6, wherein extinguishing agent is produced by admixing at least one additive to extinguishing water, proceeds according to the following steps: Pumping extinguishing water from an extinguishing water source by means of an extinguishing water pump, pumping at least one additive from an additive source by means of an additive pump which is driven by means of an electric additive pump drive, wherein the electric additive pump drive is controlled by means of an actuator, and wherein the voltage supply of the electric additive pump drive is provided via a voltage source of an on-board power supply of an emergency vehicle, in particular a fire service vehicle, Mixing the at least one additive into the extinguishing water at an admixing point located on a pressure side of the extinguishing water pump at a desired pre-adjustable or pre-set admixing rate, measuring the actual flow rate of the extinguishing water in the flow direction upstream of the admixing point by means of a flow measuring device, transmitting the actual flow rate to a control / regulation device and determining the required admixing rate of the additive based on the actual flow rate of the extinguishing water, controlling the actuator for controlling / regulating a manipulated variable of the electric additive pump drive to set the delivery rate of the additive pump corresponding to the required admixing rate.

[0019] A key aspect of the method according to the invention is that the required admixing rate is determined based on the determined actual flow rate of the extinguishing water. By means of the control and regulation device, the actuator of the additive pump drive is controlled in such a way that a manipulated variable is changed, the change in which causes the additive pump to deliver more or less additive in order to set the required admixing rate or the desired mixing ratio between extinguishing water and additive. It would be conceivable for the actuator of the additive pump drive to provide feedback on the actual manipulated variable, whereby an actual-setpoint comparison could take place, in particular by means of a comparator in the control / regulation device, in order to determine whether the manipulated variable needs to be increased or decreased. However, this is not absolutely necessary.It is advisable for the user to set or adjust a desired target proportioning rate for a specific extinguishing water flow rate on the control / regulation device, so that the measured actual flow rate already allows clear control of the actuator of the additive pump drive, thereby changing the output of the additive pump to achieve the desired proportioning rate. Should the actual extinguishing water flow rate increase, for example, due to an increase in the output of the extinguishing water pump due to additional connected consumers, this new value of the actual extinguishing water flow rate is again determined and transmitted to the control / regulation device so that the proportioning rate can be adjusted.

[0020] Furthermore, a key aspect of the invention is that the additive pump drive is supplied with power by a voltage source located on board an emergency vehicle. In contrast to the previously described prior art, it is therefore unnecessary to provide a cost-intensive and space-consuming transmission mechanism with a switchable clutch for coupling the additive pump to the vehicle engine. Due to the power supply via the on-board power supply, the electric additive pump drive of the additive pump is independent of the vehicle engine and thus independent of performance fluctuations that can occur when multiple output elements are connected to the vehicle engine simultaneously.

[0021] The actuator is a frequency converter that allows the speed of the electric additive pump drive to be varied. The inverter contained in the frequency converter allows the output voltage to be varied, allowing the speed of the additive pump drive to be adjusted. Increasing the speed increases the flow rate of the additive pump, while decreasing the speed also decreases it. By changing the amount of additive delivered, the mixing rate can be adjusted to the desired value.

[0022] The voltage source of the vehicle electrical system is expediently coupled to the actuator, in particular the frequency converter. The voltage supply for the electric additive pump drive thus runs via the actuator, which is inherent in an actuator designed as a frequency converter, but not necessarily the case with other actuators.

[0023] In a particularly preferred manner, the voltage source is a generator.

[0024] Particularly preferably, the generator is driven by a vehicle engine of the emergency vehicle.

[0025] Particularly preferably, the generator is a DC generator. In this case, cost-effective frequency converters can be used without a rectifier. Furthermore, the DC generator offers further advantages compared to AC generators. Preferably, the fire water pump is a fire extinguishing centrifugal pump connected to a power take-off of the emergency vehicle's engine. If there is a need to change the pressure at the pressure outlets, this is achieved by regulating the engine speed of the vehicle engine and thus, via the connection via the power take-off, by changing the speed of the fire extinguishing centrifugal pump. If a generator in the form of an AC generator is also connected to the power take-off, the output voltage generated by the AC generator changes depending on the engine speed.These fluctuations in the output voltage require a compensation device, such as a rectifier. However, with a DC generator, the output voltage remains constant, so changes in motor speed, for example, have no effect on the output voltage, and compensation devices such as rectifiers are unnecessary.

[0026] Particularly preferably, the generator is a low-voltage generator for generating a low voltage in the range of 30V to 60V. This distinguishes the generator from prior art voltage sources in vehicle electrical systems, which are designed for a maximum of 24V. However, with these voltage sources, the achievable delivery rate of the additive pump is insufficient. In contrast, the low-voltage generator generates a low voltage in the range of 30V to 60V, which is suitable for driving the additive pump within the required power range.

[0027] Particularly preferably, the low-voltage generator is a 48V generator. Such a 48V generator offers the aforementioned advantages over low-voltage generators with low voltages below 30V. Furthermore, the low voltage is still within the so-called extra-low voltage range, eliminating the need for additional safety measures, such as contact protection, which are absolutely essential for medium- and high-voltage ranges, thus reducing costs.

[0028] In a further development of the invention, the at least one additive is foam.

[0029] A preferred embodiment of the mixing device installed in the emergency vehicle according to the invention, with which the method according to the invention can be carried out, is illustrated in the drawing and explained in more detail below. The sole drawing shows: a schematic representation of a preferred embodiment of the mixing device for carrying out the method according to the invention.

[0030] The mixing device 11 shown in the drawing is installed in an emergency vehicle not shown in the form of a fire engine, in particular a fire extinguishing vehicle.

[0031] The mixing device 11 serves to produce extinguishing agent for fire fighting by adding at least one additive 12 to extinguishing water 13. Foam, for example, can be used as additive 12, so that the extinguishing agent is an extinguishing water / foam mixture.

[0032] As shown particularly in the drawing, the extinguishing water 13 is stored in a fire water tank 14. The tank is expediently located on board the fire engine. Alternatively, it is also possible to obtain extinguishing water 13 from extinguishing water sources external to the emergency vehicle, for example from a hydrant, fire ponds, or other bodies of water. The extinguishing water tank 14 is connected to a fire water pump 16 via a suction line 15. A shut-off valve 17 is expediently installed in the suction line 15. The fire water pump 16 is expediently designed as a fire extinguishing centrifugal pump and is driven by a vehicle engine of the emergency vehicle. The vehicle engine (not shown) generally has at least one power take-off in the form of a shaft to which the fire extinguishing centrifugal pump is coupled.

[0033] Downstream of the fire water pump 16 is a pressure line 40, which joins an additive line at a mixing point 18. Downstream of the mixing point 18, the combined line opens into several pressure outlets 19, to which, for example, fire hoses can be connected. Nozzles (not shown) are arranged at their free ends.

[0034] A non-return element 20, for example in the form of a check valve or a check flap, is installed in the line between the fire water pump 16 and the mixing point 18, which prevents the backflow of fire water or fire water / additive mixture.

[0035] Also located in the line between the extinguishing agent pump 14 and the proportioning point 18 is a flow measuring device 21. The flow measuring device 21 can, for example, have a flow sensor. In principle, all types of flow measurement are suitable, for example, acoustic, gyroscopic, magnetic-inductive, mechanical-volumetric, optical, thermal, and differential pressure / accumulation methods. In addition to the flow sensor, the flow measuring device 21 also has a measuring transducer, which is coupled to a control / regulation device 22 for signal transmission. The signal transmission from the flow measuring device 21 to the control / regulation device 22 can be wired or wireless.

[0036] In addition to the extinguishing water tank 14, the mixing device 11 also has an additive tank 23 located on board the emergency vehicle, in which additive 12, for example, foam, is stored. The additive tank 23 is connected to an additive pump 25 via an additive suction line 24. A shut-off valve 26 is also installed in the additive suction line 24.

[0037] The additive pump 25 is driven by an electric additive pump drive 27. The additive pump drive 27 is expediently an electric motor. The additive pump drive 27, for example, the electric motor, is controlled via an actuator in the form of a frequency converter 28. The frequency converter 28, in turn, is coupled to the control and regulation device 22. The signal transmission from the control and regulation device 22 to the frequency converter 28 can be wired or wireless.

[0038] A voltage source on board the emergency vehicle supplies power to the additive pump drive 27, for example, the electric motor. The voltage source is designed as a generator 29. The generator 29 is a low-voltage generator that generates a low voltage in the range of 30V to 60V. In this example, a 48V generator is used. Furthermore, the generator 29 is designed as a DC voltage generator, eliminating the need for a rectifier in the frequency converter 28, which reduces the cost of this component.

[0039] Downstream of the additive pump 25 in the flow direction is an additive pressure line 30, which connects the additive pump 25 at the mixing point 18 to the pressure line 40. A check element 26, for example a check valve or check flap, is installed in the line between the mixing point 18 and the additive pump 25 to prevent the backflow of additive or extinguishing water / additive mixture.

[0040] The method according to the invention proceeds as follows: With the shut-off valve 17 open, the extinguishing water pump 16 draws extinguishing water 13 from the extinguishing water tank 14 and conveys it via the pressure line 40 to the pressure outlets 19. At the same time, with the shut-off valve 26 open, the additive pump 25 conveys additive 12, in particular foam, from the additive tank 23 to the mixing point 18. At the mixing point 18, a specific amount of additive 12, for example foam, is added to the extinguishing water 13 based on the set mixing rate. This extinguishing water / additive mixture, i.e. the extinguishing agent, is then fed to the pressure outlets 19.

[0041] In order to keep the admixing rate constant despite a changing flow rate of extinguishing water 13, the actual flow rate of extinguishing water 13 is measured, in particular continuously, by means of the flow measuring device 21. The measuring transducer in the flow measuring device 21 generates a signal based on the measured actual value of the flow rate, which is transmitted to the control and regulation device 22. The desired admixing rate for a specific flow rate of extinguishing water 13 is already preset in the control and regulation device 22. For example, by entering a specific percentage of the extinguishing water quantity that is to be added as additive. If the flow rate of extinguishing water 13 changes, the amount of additive 12 supplied must also be readjusted. For this purpose, the control and regulation device 22 controls the frequency converter 28 using a control signal.The frequency converter 28 is connected to the generator 29, which supplies power to the electric additive pump drive 27. Depending on the incoming control signal, the frequency converter 28 controls the electric additive pump drive 27 by setting a speed of the electric additive pump drive 27 corresponding to the proportioning rate, thereby increasing or decreasing the delivery rate of the additive pump 25 as needed, so that the proportioning rate is adapted to the changing flow rate of the extinguishing water 13.

Claims

1. Emergency vehicle, in particular fire engine, having an on-board electrical system for supplying electricity to electrical consumers on board the emergency vehicle and having a mixing device (11) for the production of extinguishing agent for fire fighting by admixing at least one additive (12) to extinguishing water (13), wherein the mixing device (11) has an extinguishing water pump (16), which can draw in extinguishing water (13) from an extinguishing water source via at least one suction line (15) and supply at least one pressure outlet (19) via at least one pressure line, and wherein the mixing device (11) has an additive pump (25), which can draw in additive (12) from an additive source via at least one additive suction line (24) and supply it to an admixing point (18) via at least one additive pressure line (30), where additive (12) can be added to the extinguishing water (13) at a presettable or preset proportioning rate, wherein the additive pump (25) can be driven by means of an electric additive pump drive (27), which can be controlled via an actuator, wherein a flow measuring device (22) arranged upstream of the admixing point (18) in the direction of flow is connected into the pressure line to measure the actual flow rate of the extinguishing water (13), and wherein the mixing device (11) has a control / regulation device (22) coupled to the actuator for determining the required proportioning rate based on the measured actual flow rate, wherein the mixing device (11) is connected to the on-board electrical system of the emergency vehicle and the electric additive pump drive (27) is supplied with voltage via a voltage source of the on-board electrical system, characterized in that the actuator is designed as a frequency converter (28) for varying a speed of the electric additive pump drive (27).

2. Emergency vehicle according to Claim 1, characterized in that the voltage source is coupled to the actuator.

3. Emergency vehicle according to Claim 1 or 2, characterized in that the voltage source is designed as a generator (29).

4. Emergency vehicle according to Claim 3, characterized in that the generator (29) is designed as a low-voltage generator for producing a low voltage in the range of 30V to 60V.

5. Emergency vehicle according to one of the preceding claims, characterized in that the additive pump (25) is designed as a piston diaphragm pump.

6. Emergency vehicle according to one of the preceding claims, characterized in that the extinguishing water pump (16) is designed as a fire-fighting centrifugal pump.

7. Method for the production of extinguishing agent for fire fighting by a mixing device (11) on board an emergency vehicle according to one of Claims 1 to 6, wherein the extinguishing agent is produced by admixing at least one additive (12) to extinguishing water (13), the method having the following steps: - pumping extinguishing water (13) from an extinguishing water source by means of an extinguishing water pump (16), - pumping at least one additive (12) from an additive source by means of an additive pump (25), which is driven by means of an electric additive pump drive (27), wherein the electric additive pump drive (27) is controlled by means of an actuator, wherein the actuator is a frequency converter (28), with which a speed of the electric additive pump drive (27) can be varied and wherein the electric additive pump drive (27) is supplied with voltage via a voltage source of an on-board electrical system of an emergency vehicle, in particular fire engine, - admixing the at least one additive (12) to the extinguishing water (13) at an admixing point (18), which is at a pressure side of the extinguishing water pump (16), at a desired presettable or preset proportioning rate, - measuring the actual flow rate of the extinguishing water (13) in the flow direction upstream of the admixing point (18) by means of a flow measuring device (21), - transmitting the actual flow rate to a control / regulation device (22) and determining the required proportioning rate of the additive (12) based on the actual flow rate of the extinguishing water (13), - actuating the actuator for controlling / regulating a control variable of the electric additive pump drive (27) for setting the delivery rate of the additive pump (25) corresponding to the required proportioning rate.

8. Method according to Claim 7, characterized in that the voltage source of the on-board electrical system is coupled to the actuator.

9. Method according to Claim 7 or 8, characterized in that the voltage source is a generator (29).

10. Method according to Claim 9, characterized in that the generator (29) is a low-voltage generator for producing a low voltage in the range of 30V to 60V.

11. Method according to one of Claims 7 to 10, characterized in that the at least one additive (12) is foam.