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

Abstract

An admixing system for fire-extinguishing installations is provided for generating a mixture (premix) of extinguishing medium and extinguishing medium additive by admixing an extinguishing medium additive to an extinguishing medium. The admixing system has a motor that can be driven by a flow of extinguishing medium, an admixing pump that is connected to the motor and serves for supplying the extinguishing medium additive to an extinguishing medium additive inlet line, an admixing line, and an extinguishing medium additive outlet line from which the extinguishing medium additive is admixed to the extinguishing medium in the admixing line. The admixing pump is a piston pump having multiple cylinders and at least two outputs connected to the cylinders. At least one first output, through which return flow is possible, can be switchably fluidically connected either to a return flow line through which the extinguishing medium additive flows back to the admixing pump, or to the extinguishing medium additive outlet line. If the extinguishing medium additive flows from the return-flow-compatible output back to the admixing pump, it is therefore not admixed to the extinguishing medium in the admixing line. Thus, the admixing rate can be changed simply by means of this switching.

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 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 able to be driven by the motor, an admixing 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 at least one output for discharging the extinguishing agent additive conveyed by the admixing pump, an extinguishing agent additive inlet line having a first inlet-side end and a second pump-side end, wherein the pump-side end is fluidly connected to the input of the admixing pump, 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 outlet line having a first pump-side end and a second admixing line-side end, wherein the pump-side end is fluidly connected to the at least one output of the admixing pump and the admixing line-side end is fluidly connected to the admixing line at an admixture point, wherein the admixing pump is a piston pump, particularly a plunger pump, which has a plurality of cylinders and at least two outputs, wherein each output is fluidly connected to at least one cylinder and each cylinder is fluidly connected to exactly one output, and wherein the admixing system further comprises a return flow line having a first pump output-side end and a second pump input-side end, wherein at least one first return-flow-capable output of the admixing pump can be switched via a switching device to either be fluidly connected to the pump output-side end of the return flow line or to the pump-side end of the extinguishing agent additive outlet line; the other outputs of the admixing pump, which are not capable of return flow, are fluidly connected to the pump-side end of the extinguishing agent additive outlet line; and the pump input-side end of the return flow line is fluidly connected to the extinguishing agent additive inlet line or to the input of the admixing pump.

2. The admixing system according to claim 1, wherein a pressure retention valve for generating a counterpressure on the extinguishing agent additive flowing through the return flow line is arranged in the return flow line.

3. The admixing system according to claim 1, wherein the at least one return-flow-capable output is fluidly connected to exactly one cylinder.

4. The admixing system according to claim 1, wherein the at least one return-flow-capable output is fluidly connected to two, three or more than three cylinders.

5. The admixing system according to claim 1, wherein the admixing pump has two, three or more than three return-flow-capable outputs.

6. The admixing system according to claim 1, wherein the admixing pump has exactly three cylinders.

7. The admixing system according to claim 1, wherein the admixing pump has exactly one, exactly two, exactly four or more than four cylinders.

8. The admixing system according to claim 1, wherein the switching device is a directional control valve, particularly a ball valve.

9. The admixing system according claim 1, wherein the switching device can be switched by means of an electric drive.

10. 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, driving the input shaft of the admixing pump via the output shaft of the motor, driving the admixing pump via its input shaft, supplying the extinguishing agent additive through the extinguishing agent additive inlet line to the input of the admixing pump, pumping the extinguishing agent additive via the admixing pump, discharging the extinguishing agent additive from the at least one first return-flow-capable output of the admixing pump depending on the position of the switching device into the return flow line or into the extinguishing agent additive outlet line, if applicable, discharging the extinguishing agent additive from the return flow line into the extinguishing agent additive inlet line or to the input of the admixing pump, discharging the extinguishing agent additive from the remaining, non-return-flow-capable outputs of the admixing pump the extinguishing agent additive outlet line, admixing the extinguishing agent additive into the extinguishing agent in the admixing line at the admixture point, and dispensing the extinguishing agent/extinguishing agent additive mixture (premix) at the outlet-side end of the admixing line.

Description

[0064] FIG. 1: a flowchart of an admixing system according to the invention including additional components of a fire extinguishing system.

[0065] The admixing system 1 is supplied with extinguishing water from an extinguishing water tank (not depicted). The extinguishing water is pumped out of the extinguishing water tank by an extinguishing water pump 27 and filtered through a filter 32.

[0066] In so doing, the extinguishing water is pressurized before being fed to the water motor 2 at its inlet 3 and driving same. The water motor 2 preferably works according to the reciprocating piston or rotational principle.

[0067] 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).

[0068] A portion of the extinguishing water pumped by the extinguishing water pump 27 is already branched off into a flushing line 47 ahead (i.e. upstream) of the water motor 2, provided the stopcock 18 disposed therein is open, filtered in a filter 19, and fed as flushing water to the input 7 of an admixing pump 6 via a check valve 20. The admixing pump 6 can in this way be flushed with extinguishing water without a separate flushing water reservoir needing to be provided for the purpose.

[0069] 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. In the exemplary embodiment, the admixing pump 6 is preferably a plunger pump or an adjustable plunger pump having three cylinders.

[0070] The extinguishing agent additive, in particular a foaming agent, is provided in the extinguishing agent additive tank 24. The extinguishing agent additive passes through an extinguishing agent additive inlet line 35 from its inlet-side end 36, which is fluidly connected to the extinguishing agent additive tank 24 via a stopcock 39, a sight glass 17, through which the proper conveying of the extinguishing agent additive can be monitored, and a non-return flap 33 to the pump-side end 37 of the extinguishing agent additive inlet line 35 and thus to the input 7 of the admixing pump 6. The non-return flap 33 prevents flushing water from the flushing line 47 from entering into the extinguishing agent additive inlet line 35. The extinguishing agent additive is drawn in by the admixing pump 6, pressurized by same, and pumped to the outputs 8a, 8b of the admixing pump 6. The admixing pump 6 is protected from excessively high pressures by a pressure relief valve 38.

[0071] The admixing pump 6 in the exemplary embodiment exhibits two outputs 8a and 8b. The output 8a not capable of return flow is fluidly connected to the third cylinder and the return-flow-capable output 8b to the first and the second cylinder of the admixing pump 6. In another embodiment, the output 8a not capable of return flow can also be connected to two cylinders, for instance the second and third cylinder, and the return-flow-capable output 8b to one cylinder, for instance the first cylinder.

[0072] From the non-return-flow-capable output 8a of the admixing pump 6, the extinguishing agent additive conveyed via the third cylinder first reaches, via a conveying line 40 for the third cylinder, the 3-way “Admixture/Return” ball valve 34, the function of which is described in greater detail below, and in the corresponding “Admixture” position of the 3-way ball valve 34, the pump-side end 14 of extinguishing agent additive outlet line 13.

[0073] The conveying line 40 for the third cylinder can be vented via a bleeder valve 46, whereby any air contained in the extinguishing agent additive can flow out into the ambient air via a hose 42 and an overflow opening 43. The pressure of the extinguishing agent additive in the conveying line 40 can be monitored via a manometer 45 connected to the conveying line 40 via a stopcock 21.

[0074] A surge tank 22 is further connected to the conveying line 40. The surge tank 22 functions as a snubber and suppresses pulsations in the extinguishing agent additive flow triggered by the oscillating movement of the pistons of the admixing pump 6 preferably configured as a plunger pump. The surge tank 22 can in particular be a compressed air chamber or a tubular membrane pulsation damper.

[0075] The extinguishing agent additive passes through a check valve 26 in the extinguishing agent additive line 13 to the admixing line-side end 15 of the extinguishing agent additive outlet line 13 where it is fluidly connected to admixing line 10. This is also the location of admixture point 16 at which the extinguishing agent additive mixes with the extinguishing water. The check valve 26 prevents extinguishing water from being able to enter the extinguishing agent additive outlet line 13 via admixture point 16.

[0076] From the return-flow-capable output 8b of the admixing pump 6, the extinguishing agent additive conveyed by the first and second cylinders reaches a “cylinder cut-off” ball valve 28 via a first conveying line 41a for the first and second cylinders. In the “No cut-off” position of ball valve 28, the extinguishing agent additive likewise reaches the 3-way “Admixture/Return” ball valve 34 via a second conveying line 41b for the first and second cylinders and from there, in a corresponding position of the 3-way ball valve 34, enters into the extinguishing agent additive outlet line 13 in the same way as the extinguishing agent additive conveyed by the third cylinder and is mixed with the extinguishing water in the admixing line 10 at admixture point 16.

[0077] By synchronizing the flow rates of the extinguishing water flow in admixing line 10 and the extinguishing agent additive flow in extinguishing agent additive outlet line 13, the volumetric ratio between the admixed extinguishing agent additive and extinguishing water; i.e. the admixture rate, is substantially constant, provided that the cylinder has not been cut off, due to the coupling of the water motor 2 to the admixing pump 6. In the just described state of the admixing system 1; i.e. without cylinder cut-off, the admixture rate is for example 3%.

[0078] If, on the other hand, the ball valve 28 is set to the “cut-off” position, the extinguishing agent additive conveyed by the first and second cylinders passes from the first conveying line 41a into the pump output-side end 30 of the return flow line 29 through said return flow line 29 to its pump input-side end 31 and there re-enters admixing pump 6, either at its input 7 or—as depicted in FIG. 1—at a separate input of the admixing pump 6. A pressure retention valve 23 generates a counterpressure on the extinguishing agent additive flowing through return flow line 29 which creates substantially the same pressure conditions in the first and second cylinders as in the third cylinder of the admixing pump 6 and thereby ensures that the admixing pump 6 runs smoothly.

[0079] In this state of the admixing system 1; i.e. when the first and second cylinders are cut off, the admixture rate is for example only 1% instead of 3%, since only the third cylinder still conveys the extinguishing agent additive into extinguishing agent additive outlet line 13 and thus only a third of the maximum amount of extinguishing agent additive is mixed with the extinguishing water per unit of time.

[0080] In addition to the above-described “Admixture” position, the 3-way ball valve 34 can also be set into the further “Return” position. In this position of the 3-way ball valve 34, the extinguishing agent additive from conveying line 40 for the third cylinder and, if applicable, from the second conveying line 41b for the first and second cylinder is not conducted to admixture point 16 but rather back into the extinguishing agent additive tank 24 via a return line 44.

[0081] Further measuring devices (not depicted) can measure the admixture rate during this operating mode of the admixing system 1. The extinguishing agent additive is however not thereby actually mixed into the extinguishing water and is thus not lost due to the control measurement.

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] 8a non-return-flow-capable output of admixing pump [0090] 8b return-flow-capable output of admixing pump [0091] 9 admixing pump input shaft [0092] 10 admixing line [0093] 11 motor-side end of admixing line [0094] 12 outlet-side end of admixing line [0095] 13 extinguishing agent additive outlet line [0096] 14 pump-side end of extinguishing agent additive outlet line [0097] 15 admixing line-side end of extinguishing agent additive outlet line [0098] 16 admixture point [0099] 17 sight glass [0100] 18 stopcock valve [0101] 19 filter [0102] 20 check valve [0103] 21 stopcock valve [0104] 22 surge tank [0105] 23 pressure retention valve [0106] 24 extinguishing agent additive tank [0107] 25 clutch [0108] 26 check valve [0109] 27 extinguishing water pump [0110] 28 “Cylinder cut-off” ball valve [0111] 29 return flow line [0112] 30 pump output-side end of return flow line [0113] 31 pump input-side end of return flow line [0114] 32 filter [0115] 33 non-return flap [0116] 34 3-way “Admixture/Return” ball valve [0117] 35 extinguishing agent additive inlet line [0118] 36 inlet-side end of extinguishing agent additive inlet line [0119] 37 pump-side end of extinguishing agent additive inlet line [0120] 38 pressure relief valve [0121] 39 stopcock valve [0122] 40 conveying line for the third cylinder [0123] 41a first conveying line for the first and second cylinders [0124] 41b second conveying line for the first and second cylinders [0125] 42 hose [0126] 43 overflow opening [0127] 44 return line [0128] 45 manometer [0129] 46 bleeder valve [0130] 47 flushing line