ADMIXING SYSTEM FOR FIRE EXTINGUISHING SYSTEMS AND METHOD FOR OPERATING SUCH AN ADMIXING SYSTEM

Abstract

A admixing system for fire extinguishing systems for producing an extinguishing agent-extinguishing agent additive mixture (premix) by mixing an extinguishing agent additive with an extinguishing agent. The admixing system has a motor that can be driven by a flow of extinguishing agent, an admixing pump connected to the motor for pumping the extinguishing agent additive, an admixing line, and an extinguishing agent additive line, from which the extinguishing agent additive is mixed with the extinguishing agent in the admixing line. The admixing system has a branching line, from which a part of the flow of extinguishing agent can be branched off if the load in the fire extinguishing system only requires a small flow of extinguishing agent. In this manner, the flow of extinguishing agent flowing through the motor is artificially increased so that the motor runs in a higher rotational speed range in which a reliable operation of the motor is ensured (a so-called start-up flow reduction). The admixing system has a motor rotational speed measuring device and a controller, said controller being designed to completely or partly open and/or close the branching valve on the basis of the motor rotational speed measured by the motor rotational speed measuring device.

Claims

1. An admixing system for fire extinguishing systems for producing an extinguishing agent/extinguishing agent additive mixture (premix) by admixing an extinguishing agent additive, in particular a foaming agent, to an extinguishing agent, in particular water, comprising a motor, in particular a water motor, able to be driven by a flow of extinguishing agent which has an inlet for supplying the extinguishing agent to the motors, 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 able to be driven by the motor, an admixing pump, in particular a piston pump, for conveying the extinguishing agent additive which has an input shaft coupled to the output shaft of the motor, an input for providing the extinguishing agent additive, in particular from an extinguishing agent additive tank or from an extinguishing agent additive supply line, and an output for discharging the extinguishing agent additive, an admixing line having a first motor-side end and a second outlet-side end, wherein the motor-side end is fluidly connected to the outlet of the motor, an extinguishing agent additive line having a first pump-side end and a second admixing line-side end, wherein the pump-side end is fluidly connected to the output of the admixing pump and the admixing line-side end is fluidly connected to the admixing line at an admixture point, which is different from the motor-side end of the admixing line, a branching line with a first, admixing line-side end and a second, outlet-side end, wherein the admixing line-side end is fluidly connected to the admixing line at a branching point located between the motor-side end of the admixing line and the admixture point, and a branching valve arranged in the branching line, wherein the admixing system additionally comprises a motor rotational speed measuring device and a controller, and that the controller is designed to fully or partially open and/or close the branching valve on the basis of the rotational speed of the motor measured by the motor rotational speed measuring device.

2. The admixing system according to claim 1, wherein the controller is configured to fully open the branching valve when the branching valve is closed and the motor's rotational speed is greater than zero and below a first predefined rotational speed (Umin).

3. The admixing system according to claim 2, wherein the rotational speed of the motor in the range of the first predefined rotational speed (Umin) is substantially proportional to the flow rate of the extinguishing agent flow driving the motor.

4. The admixing system according to claim 1, wherein the controller is configured to fully close the branching valve when the branching valve is open and the motor's rotational speed is above a second predefined rotational speed (Umin).

5. The admixing system according to claim 4, wherein the rotational speed of the motor in the range of the second predefined rotational speed (Umin) is substantially proportional to the flow rate of the extinguishing agent flow driving the motor.

6. The admixing system according to claim 1, wherein the controller is configured to partially open and/or close the branching valve as a function of the motor's measured rotational speed thus far that the sum of the flow rate of the extinguishing agent flow in the branching line and the flow rate of the extinguishing agent flow on the outlet-side end of the admixing line substantially corresponds to the flow rate of an extinguishing agent flow driving the motor at a third predefined rotational speed (Umin).

7. The admixing system according to claim 6, wherein the rotational speed of the motor in the range of the third predefined rotational speed (Umin) is substantially proportional to the flow rate of the extinguishing agent flow driving the motor.

8. The admixing system according to claim 1, wherein the extinguishing agent flow can be discharged into the surroundings of the admixing system at the outlet-side end of the branching line.

9. A method for operating an admixing system according to claim 1 having the following steps: directing a flow of extinguishing agent to the inlet of the motor, driving the motor via the flow of extinguishing agent, driving the output shaft of the motor via the motor, discharging the extinguishing agent from the outlet of the motor into the admixing line, branching off a portion of the extinguishing agent from the admixing line into the branching line at the branching point if the branching valve is fully or partially open, discharging the branched-off portion of the extinguishing agent at the outlet-side end of the branching line, driving the input shaft of the admixing pump via the output shaft of the motor, driving the admixing pump via its input shaft, providing the extinguishing agent additive at the input of the admixing pump, pumping the extinguishing agent additive via the admixing pump, discharging the extinguishing agent additive from the output of the admixing pump into the extinguishing agent additive line, admixing the extinguishing agent additive into the extinguishing agent in the admixing line at the admixture point, dispensing the extinguishing agent/extinguishing agent additive mixture (premix) at the outlet-side end of the admixing line, measuring the rotational speed of the motor via the motor rotational speed measuring device, and fully or partially opening and/or closing the branching valve via the controller as a function of the measured rotational speed of the motor.

Description

[0055] Further advantages, features and possible applications of the present invention will become apparent from the following description in conjunction with the figure. Thereby shown is:

[0056] FIG. 1: a flowchart of an admixing system according to the invention including additional components of a fire extinguishing system.

[0057] The admixing system 1 is supplied with extinguishing water from an extinguishing water tank 23, the fill level of which can be monitored via a float 47. The extinguishing water is pumped out of the extinguishing water tank 23 by an extinguishing water pump 27, which is driven by a motor 29 via clutch 28, and in doing so filtered through a filter 32. A respective check valve 30, 31 is in each case arranged ahead of the extinguishing water pump 27 and behind the filter 32.

[0058] In this way, the extinguishing water is pressurized prior to being fed to the water motor 2 and driving same. The water motor 2 preferably works according to the displacement principle, further preferably according to the reciprocating piston or rotational principle.

[0059] The extinguishing water reaches the motor-side end 11 of the admixing line 10 at the outlet 4 of the water motor 2 and is directed from there through the admixing line 10 to its outlet-side end 12 to which are connected the load(s) of the fire extinguishing system such as one or more sprinkler nozzles or a foaming nozzle and firefighting monitor (none of which are shown).

[0060] The output shaft 5 of the water motor 2 is connected to the input shaft 9 of the admixing pump 6 via a clutch 25. The input shaft 9 of the admixing pump 6 is thus also set into rotational motion with the output shaft 5 of the water motor 2 and in turn drives the admixing pump 6. The admixing pump 6 preferably a plunger pump or an adjustable plunger pump.

[0061] The admixing pump 6 pumps an extinguishing agent additive, in particular a foaming agent provided in the extinguishing agent additive tank 24, its fill level likewise being able to be monitored via a float 42. Passing through a stopcock valve 40 and a non-return flap 41, the extinguishing agent additive first reaches a 3-way ball valve 44, the function of which will be discussed below, and in the corresponding “Suction” position of the 3-way ball valve 44, input 7 of the admixing pump 6 where it is drawn in by the admixing pump 6, pressurized by same, and conveyed to the output 8 of the admixing pump 6.

[0062] The extinguishing agent additive reaches the pump-side end 14 of extinguishing agent additive line 13 at the output 8 of admixing pump 6. The admixing pump 6 and the extinguishing agent additive line 13 can be vented via a bleeder valve 51. The pressure of the extinguishing agent additive in extinguishing agent additive line 13 can be monitored via a manometer 45.

[0063] In extinguishing agent additive line 13, the extinguishing agent additive first reaches a 3-way ball valve 34, the function of which will also be described below, and in the corresponding “Admixture” position of the 3-way ball valve 34, the admixing line-side end 15 of the extinguishing agent additive line 13 where it connects to admixing line 10. This is also the location of admixture point 16, at which the extinguishing agent additive is added to the extinguishing water.

[0064] By synchronizing the flow rates of the extinguishing water flow in admixing line 10 and the extinguishing agent additive flow in extinguishing agent additive line 13, the volumetric ratio between the admixed extinguishing agent additive and extinguishing water; i.e. the admixture rate, is substantially constant, for example 3%, due to the coupling of the water motor 2 to the admixing pump 6.

[0065] A non-return flap 33 arranged ahead (i.e. upstream) of the admixture point 16 in extinguishing agent additive line 13 prevents extinguishing water from being able to enter the extinguishing agent additive line 13 in the direction of the admixing pump 6. Correspondingly, a non-return flap 33 arranged ahead (i.e. upstream) of the admixture point 16 in admixing line 10 prevents extinguishing agent additive from being able to enter into admixing line 10 in the direction of the water motor 2.

[0066] In addition to the two positions described above, the 3-way ball valves 34, 44 can each be brought into a further position in order to initiate an additional function of the admixing system 1:

[0067] In the further “Return” position of the 3-way ball valve 34, the extinguishing agent additive from extinguishing agent additive line 13 is not directed to the admixture point 16 but rather, via a return line 35 and a counterpressure valve 37, to an extinguishing agent additive measuring tank 36, the fill level of which can be monitored by a float 38. A pressure relief valve 52 having a greater opening pressure than that of the counterpressure valve 37 is provided ahead (i.e. upstream) of the 3-way ball valve 34 in a further line between the extinguishing agent additive line 13 and the extinguishing agent additive measuring tank 36.

[0068] Doing so enables measuring the volume of the extinguishing agent additive conveyed by the admixing pump 6 over a specific interval of time and comparing it to the—e.g. calculated—volume of extinguishing water flowing through the water motor 2 during the same time interval. This enables monitoring adherence to the desired admixture rate.

[0069] The return of the extinguishing agent additive into extinguishing agent additive measuring tank 36 allows the described control measurement to be performed without the extinguishing agent additive actually needing to be mixed with the extinguishing water. The extinguishing agent additive collected in the extinguishing agent additive measuring tank 36 can then be returned to the extinguishing agent additive tank 24 again via a stopcock valve 39 and is thus not lost due to the control measurement.

[0070] In the further “Flushing” position of the 3-way ball valve 44, a portion of the extinguishing water is already branched off ahead of (i.e. upstream) the water motor 2 and directed into the admixing pump 6 in order to flush it. The extinguishing water used to flush the admixing pump 6 then, as described above for the extinguishing agent additive, flows through extinguishing agent additive line 13 back into the admixing line 10 at admixture point 16. The admixing pump 6 can in this way be flushed with extinguishing water such that no separate reservoir of flushing water needs to be provided for the purpose.

[0071] Instead of providing ball valve 44, the three lines which are connected to the ball valve 44 can, alternatively, also be directly connected together in a fluid-conducting manner (similar as at admixture point 16). Instead of the ball valve 44, a stopcock valve and a non-return flap are then preferably arranged in the line coming from the extinguishing water pump 27 and branched off ahead of the water motor 2 (not depicted).

[0072] The open stopcock valve then corresponds to the “Flushing” position of the 3-way ball valve 44, whereby the branched-off portion of the extinguishing water is directed into the mixing pump 6 in order to flush it, and the closed stopcock valve corresponds to the above-described “Suction” position of the 3-way ball valve 44. The non-return flap prevents the extinguishing agent additive from entering into the line coming from the extinguishing water pump 27, and from there the water motor 2. Conversely, the non-return flap 41 prevents extinguishing water from entering into the extinguishing agent additive tank 24.

[0073] If the load—for example a sprinkler system in which only one or just a few sprinklers are open—only requires a small flow of extinguishing agent at the outlet-side end 12 of the admixing line 10, only a correspondingly low rotational speed of the water motor 12 is likewise required. In order to circumvent the unreliability of the water motor 2 and its poor efficiency at low rotational speeds, a portion of the extinguishing water flow is branched off from the admixing line 10 via a branching line 17 and the flow of extinguishing water through the water motor 2 thereby artificially increased. The branched-off portion of the extinguishing water flow is then returned to the extinguishing water tank 23 and is thus not lost.

[0074] The admixing line-side end 18 of the branching line 17 is located at a branching point 20 in the admixing line 10 and the outlet-side end 19 of the branching line 17 is connected to the extinguishing water tank 23. The branching point 20 being located on the admixing line 10 ahead of (i.e. upstream) the non-return flap 43 and admixture point 16 ensures that only extinguishing water, albeit no extinguishing agent additive or premix, enters the branching line 17 and from there ends up back in extinguishing water tank 23.

[0075] The branching line 17 can be opened and closed by a controllable branching valve 21. A slide valve 49, a pressure reducer 50, another slide valve 48 and a gate 26 are arranged on the branching line 17 after (i.e. downstream of) branching valve 21. The pressure on the branching line 17 can be monitored by a manometer 46.

[0076] The branching line 17 serves to reduce start-up flow; i.e. ensure reliable operation of the water motor 2 even with low flows of extinguishing agent being required at the outlet-side end 12 of the admixing line 10, by the circulation of an additional branched-off flow of extinguishing water through the water motor 2. This thereby enables being able to decrease the minimum flow of extinguishing agent as of which the required admixture rate is reliably achieved, for example from 200 l/min to 60-80 l/min, thus to about a third. The motor speed associated with this minimum extinguishing agent flow is referred to in the following as U.sub.min.

[0077] The start-up flow reduction is controlled by a controller (not depicted) of the admixing system 1. Same is connected to a motor rotational speed measuring device 22 which continuously measures the rotational speed of the water motor 2. The motor rotational speed measuring device 22 can for example be a proximity switch attached to the clutch 25 which receives a pulse from a magnetic pulse generator attached to one of the shafts 5, 9 upon each revolution of the shafts 5, 9. From that, the proximity switch itself or the controller then determines the rotational speed of the water motor 2.

[0078] The controller is furthermore connected to the branching valve 21 and can open and close it via the corresponding signals. The example embodiment only provides signals for the full opening/full closing of the branching valve 21. It is, however, also possible to output signals for only a partial opening/partial closing of the branching valve 21, provided this has the appropriate efficiency.

[0079] Preferably, the controller opens branching valve 21 as soon as the motor rotational speed measuring device 22 detects a motor speed greater than 0 but less than U.sub.min. In this range of rotational speed, the water motor 2 has already started up; i.e. the admixing system 1 is in operation, although the required flow of extinguishing agent is lower than needed for reliable operation of the water motor 2. Therefore, by opening the branching valve 21, a portion of the extinguishing water flow flowing through the water motor 2 is branched off into branching line 10 for the purpose of start-up flow reduction.

[0080] Accordingly, the controller closes the branching valve 21 as soon as the motor rotational speed measuring device 22 detects a motor speed greater than U.sub.min.

[0081] The water motor 2 then runs in a rotational speed range which guarantees its reliable operation. Start-up flow reduction is thus not necessary and the branching can be disabled by closing branching valve 21.

LIST OF REFERENCE NUMERALS

[0082] 1 admixing system

[0083] 2 water motor

[0084] 3 water motor inlet

[0085] 4 water motor outlet

[0086] 5 water motor output shaft

[0087] 6 admixing pump

[0088] 7 admixing pump input

[0089] 8 admixing pump output

[0090] 9 admixing pump input shaft

[0091] 10 admixing line

[0092] 11 motor-side end of admixing line

[0093] 12 outlet-side end of admixing line

[0094] 13 extinguishing agent additive line

[0095] 14 pump-side end of extinguishing agent additive line

[0096] 15 admixing line-side end of extinguishing agent additive line

[0097] 16 admixture point

[0098] 17 branching line

[0099] 18 admixing line-side end of the branching line

[0100] 19 outlet-side end of the branching line

[0101] 20 branching point

[0102] 21 branching valve

[0103] 22 motor rotational speed measuring device

[0104] 23 extinguishing water tank

[0105] 24 extinguishing agent additive tank

[0106] 25 clutch

[0107] 26 gate

[0108] 27 extinguishing water pump

[0109] 28 extinguishing water pump clutch

[0110] 29 extinguishing water pump motor

[0111] 30 check valve

[0112] 31 check valve

[0113] 32 filter

[0114] 33 non-return flap

[0115] 34 3-way “Admixture/Return” ball valve

[0116] 35 return line

[0117] 36 extinguishing agent additive measuring tank

[0118] 37 counterpressure valve

[0119] 38 float

[0120] 39 stopcock valve

[0121] 40 stopcock valve

[0122] 41 non-return flap

[0123] 42 float

[0124] 43 non-return flap

[0125] 44 3-way “Flushing/Suction” ball valve

[0126] 45 manometer

[0127] 46 manometer

[0128] 47 float

[0129] 48 slide valve

[0130] 49 slide valve

[0131] 50 pressure reducer

[0132] 51 bleeder valve

[0133] 52 bleeder valve