JPH0574381B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a fire extinguishing equipment that mixes water and fire extinguishing foam and is used for extinguishing facilities such as chemical factories, oil refineries, oil tanks, and parking lots. This invention relates to a foam extinguishing agent mixing device.

[Prior Art] The outline of a conventional fire extinguishing equipment using fire extinguishing foam is as shown in FIG. In other words, when a fire breaks out in a certain area and it becomes necessary to extinguish the fire,
An automatic valve 3 provided at the base end of a branch pipe 2 to which a foaming device consisting of a foam discharge head 1 installed in the area is connected is opened by an interlock control signal from a fire detector or the like. Then, the pressurized water supply device consisting of the pump 4 is activated and starts supplying pressurized water from the water source 5 to the main pipe 6. A mixer 7 is provided in the middle of the main pipe 6, and a part of the pressurized water in the main pipe 6 expands the diaphragm 9 of the foam concentrate tank 8 to send the foam extinguishing agent to the mixer 7, and the pressurized water are mixed at the specified ratio. This pressurized mixture of fire extinguishing foam and water is supplied to the foam discharge head 1 through the opened automatic valve 3, and is foamed and discharged from the foam discharge head 1.

[Problems to be Solved by the Invention] By the way, in a mixing device consisting of a mixer as described above, there is a flow rate range that can obtain a mixture liquid with a mixing ratio suitable for obtaining appropriate foam from the foam discharge head [this is not practical]. The working flow rate range] is up to 4 times the minimum flow rate for the orifice type and about 6 times for the ventilate type, assuming the minimum flow rate is 1. Therefore, as the number of foam discharging heads used at one time increases, the flow rate also increases accordingly, so it is desirable to obtain a mixture with an appropriate mixing ratio using the conventional mixing device as described above. There was a limit to the number of foam discharge heads that could be installed in fire extinguishing equipment.

[Means for Solving the Problems] The foam extinguishing agent mixing device according to the present invention connects a plurality of mixers having different practical flow rate ranges in parallel through automatic release valves, and each mixer has a Each is equipped with a differential pressure detector to detect differential pressure,
The above problem is solved by controlling each automatic opening valve by a detection signal from a differential pressure detector attached to another mixer.

[Function] With the above configuration, the differential pressure detector attached to the currently operating mixer detects an increase in the differential pressure when the flow rate of the mixed liquid increases,
Conversely, when the flow rate decreases, a decrease in differential pressure is detected. Based on this detection signal, it is detected whether the flow rate of the mixed liquid is within the practical use flow rate range,
When the flow rate is above the range, the automatic release valve connected to another mixer is controlled to open so that a proper mixed liquid can be obtained even at a higher flow rate, and when the flow rate is below the range, it is connected to itself. The automatically opened valve is controlled to close so that a proper mixed liquid can be obtained even at a lower flow rate in other mixers that are in operation.

[Example] An example of the foam fire extinguishing agent mixing device according to the present invention will be explained based on the drawings. Fig. 1 is a schematic diagram showing the configuration of the foam fire extinguishing agent mixing device according to the present invention. Mixers, that is, mixer 10 for small flow range, mixer 11 for medium flow range, and mixer 12 for large flow range are connected in parallel. Among these, automatic opening valves 13 and 14 are connected in series to the medium and large flow range mixers 11 and 12, and electromagnetic valves 15 and 16 are provided as opening means, respectively. Differential pressure detectors 17, 18, 19 are attached to each mixer 10, 11, 12, and each automatic release valve 13, 14 is activated based on detection signals from these differential pressure detectors 17, 18, 19. Controller 2 to control
0 is set.

The operation of the foam extinguishing agent mixing device according to the present invention configured as described above will be explained below.

Here, the minimum flow rate of the entire equipment is 50/min, the maximum flow rate is 5000/min, and the small flow area mixer 1
The practical use flow rate range of 0 is 50 to 30/min, that of mixer 11 for medium flow range is 200 to 1200/min, and that of mixer 12 for large flow range is 800 to 5000/min.
shall be. The relationship between the flow rate and differential pressure of each of these mixers 10, 11, 12 is as shown in the characteristic curve diagram in FIG.
Accordingly, the characteristics of the mixer 11 for medium flow range are shown by curve B, and the characteristics of the mixer 12 for large flow range are shown by curve C.
It is displayed by. As is clear from the characteristic diagram, each mixer 10, 11, 12 has a differential pressure of 0.2 Kgf/cm ² at the minimum flow rate and 3.0 at the maximum flow rate.
It is expressed as Kgf/ ^cm2 .

Now, under normal conditions, both automatic release valves 1
3 and 14 are closed. When a fire occurs and the fire pump 21 starts, the fire extinguishing water flows into the water main 22.
The water flows from there to the bypass pipe 23 for the small flow area, and the mixer 10 for the small flow area operates. Here, it is mixed with the foam fire extinguishing agent and discharged as fire extinguishing foam from the foam discharge head 25 connected to the branch pipe 24. During this operation, the differential pressure detector 17 attached to the small flow range mixer 10 detects the differential pressure and continues to send a detection signal to the controller 20. This differential pressure
While the flow rate is in the range of 0.2 to 3.0 Kgf/cm ² , that is, while the flow rate is in the range of 50 to 300/min, both automatic release valves 13 and 14 remain closed. only works.

As the number of foam discharge heads 25 for discharging fire extinguishing foam increases as the fire spreads, the flow rate also increases, eventually reaching a flow rate exceeding 300/min. Then, the controller 20 detects 3.0 from the differential pressure detector 17.
When a detection signal exceeding Kgf/cm ² is received, the solenoid valve 15
The automatic release valve 13 is opened and the medium flow range mixer 11 is operated. This results in
Even at a flow rate of 300/min or more, it becomes possible to obtain a liquid mixture with an appropriate mixing ratio.

When the flow rate increases further and finally exceeds 1200/min, the controller 20 detects the differential pressure detector 1.
Upon receiving a detection signal exceeding 3.0Kgf/cm ² from 8,
An open signal is sent to the solenoid valve 16 to open the automatic release valve 14 and operate the large flow range mixer 12.
As a result, a liquid mixture with an appropriate mixing ratio can be obtained even in a large flow rate range of 1200/min or more and 5000/min.

Next, when the fire subsides and the number of foam discharge heads 25 that discharge extinguishing foam decreases, the flow rate also decreases to 800/min or less, and the controller 20 detects the differential pressure. 0.2 from vessel 19
Upon receiving the detection signal below Kgf/ ^cm2 , the solenoid valve 16
A close signal is sent to the automatic release valve 14 to close the large flow range mixer 12. This results in
A liquid mixture with an appropriate mixing ratio can be obtained even at a flow rate of 800/min or less.

In the same way, the flow rate is further reduced to 200/
When the pressure reaches min, the controller 20 receives a detection signal of less than 0.2Kgf/cm ² from the differential pressure detector 18, sends a closing signal to the solenoid valve 15, and sends a closing signal to the automatic open valve 1.
3 is closed to stop the medium flow range mixer 11. As a result, a liquid mixture with an appropriate mixing ratio can be obtained even at a flow rate of 200/min or less.

[Effects of the Invention] As described above, the foam extinguishing agent mixing device according to the present invention connects a plurality of mixers having different practical flow rate ranges in parallel through automatic release valves, and
Each mixer is equipped with a differential pressure detector that detects the differential pressure, and each automatic opening valve is controlled by the detection signal of the differential pressure detector attached to the other mixer. It is possible to continuously obtain a liquid mixture with an appropriate mixing ratio for an extremely wide range of flow rates, which could not be obtained with a single mixer. Furthermore, in its configuration, the mixer can be used not only as a proportional mixer for mixing fire extinguishing foam with fire extinguishing water, but also as a differential pressure flow meter, which has the advantage that the entire equipment can be manufactured at a low cost.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the foam extinguishing agent mixing device according to the present invention, FIG. 2 is a characteristic curve diagram showing the relationship between flow rate and differential pressure used to explain the device of FIG. 1, and FIG. FIG. 3 is a schematic diagram of a fire extinguishing equipment using a conventional foam fire extinguishing agent. 21... Pressurized water supply device, 25... Foaming device, 1
0, 11, 12... mixer, 13, 14... automatic release valve, 17, 18, 19... differential pressure detector.

Claims (1)

[Claims] 1. In a foam extinguishing agent mixing device that is located between a pressurized water supply device and a foaming device and consists of a mixer that mixes foam extinguishing agent into flowing water, a plurality of mixers with different flow rate ranges for practical use are each connected to an automatic release valve. Each mixer is connected in parallel through the mixer, and each mixer is equipped with a differential pressure detector for detecting the differential pressure, and each of the automatic release valves receives a detection signal from the differential pressure detector attached to the other mixer. A foam extinguishing agent mixing device characterized by being controlled by.