JPH0515334Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a device for mixing fire extinguishing foam in a uniform proportion in water discharged from a fire pump.

(Prior art) Although it depends on the type of fire, when a fire pump mixes fire extinguishing foam with fire extinguishing water and sprays it, the conventional technique shown in Figure 2 is to mix the foam (chemical solution) in an even ratio. A similar mixing device was used.

This is called a pressure feed automatic proportional mixing system, and in the figure, 1 is a fire pump, 2 is a water turret, 3 is a chemical tank containing a chemical solution to be used as a foaming agent, and 4 is a chemical pump. By driving the fire pump 1, fire extinguishing water is pumped from the main pipe 5 to the water turret 2.

Further, by driving the chemical liquid pump 4, the chemical liquid from the chemical liquid tank 3 is pumped through the pipe 6 through the mixer 7 into the main pipe 5 through which high-pressure fire extinguishing water flows.

In order to keep the mixing ratio of both constant, mixer 7
An orifice is provided at each inlet of the orifice, and the upstream pressure of each orifice is guided as pilot pressure through pipes 9 and 10 to both chambers defined by the diaphragm of an equal pressure valve (constant differential pressure valve) 11, etc. Pressure valve 1
1 adjusts the chemical pressure in the pipe 6 so that these pressures become equal.

Note that when the chemical liquid is actually mixed, the valve 12A is closed and the valve 12B is opened so that the chemical liquid in the pipe 6 passes through the equal pressure valve 11.

The flow rates of fire extinguishing water and chemical solution flowing into the mixer 7 are:
It changes in proportion to the opening area of each orifice and its upstream pressure, and if the orifice opening is constant, the flow rate increases as the pressure increases. Therefore, if the upstream pressures of both orifices are maintained the same, the flow rate ratio is proportional only to the opening degree of the orifices, and a constant mixing ratio is always maintained.

The equal pressure valve 11 detects the pressure upstream of each orifice, and for example, when the pressure on the chemical side is high, it operates in conjunction with the diaphragm to reduce the opening of the chemical liquid piping 6 to lower the pressure, and conversely, when the pressure is low, it reduces the opening. It expands and increases the pressure, and in this way it is controlled so that both pressures always match. As a result, the mixing ratio of the chemical solution (foam) to the fire extinguishing water is always adjusted to be constant.

Note that the mixture ratio can also be adjusted to a constant value by controlling the equal pressure valve 11 to always maintain a constant differential pressure.

(Problem to be solved by the invention) However, in this device, since the chemical liquid piping 6 is connected to the discharge side of the fire pump 1, that is, the secondary side, the supply pressure of the chemical liquid is equal to the discharge pressure of the fire pump 1. I needed to increase it until it matched. Therefore, a high-pressure pump is required as the chemical pump 4.
There was a problem that chemical pumps became very expensive.

Further, since the mixer 7 is provided with an orifice to restrict the flow path, there is a problem in that the pressure loss is large and the pump efficiency is also reduced.

The present invention was proposed in order to solve such problems, and its purpose is to provide a device that can accurately mix chemical liquid into the suction side of a fire pump.

(Means for solving the problem) Therefore, the present invention connects the chemical liquid piping from the chemical liquid pump in the middle of the suction piping of the fire pump, and inserts a pressure regulating valve and a variable orifice in series in the middle of this chemical liquid piping. The pressure regulating valve is composed of a member that responds to the detected pressure of a flow rate detection section provided in the discharge piping of the fire pump and the pressure upstream of the variable orifice, and a valve body connected to this pressure responsive member, and the pressure regulating valve is configured to adjust the pump discharge flow rate. The amount of chemical liquid mixed is controlled in proportion to.

(Function) Therefore, since the chemical liquid is mixed into the suction side of the fire pump, the required supply pressure of the chemical liquid is low, and even if the passage pressure fluctuates using the pressure regulating valve, the mixing ratio can be accurately controlled. .

(Example) An example of the present invention will be described below with reference to FIG. A chemical liquid pipe 6 from a chemical liquid tank 3 is connected to the middle of a suction pipe 5A of a fire pump 1 that pumps fire extinguishing water.

A water discharge turret 2 is connected to the discharge pipe 5B of the fire pump 1, and discharges fire extinguishing water.

An amplification type pressure regulating valve (balance regulator) 15 and a variable orifice 16 for adjusting the mixing ratio according to the type of chemical liquid are interposed in the middle of the chemical liquid piping 6.

The pressure regulating valve 15 is equipped with two first and second diaphragm devices 17 and 18 having different sizes and pressure receiving areas, and a regulating valve body 20 is integrally attached in the middle of a rod 19 that connects both diaphragms 17A and 18A. , the valve opening degree increases or decreases as the rod 19 is displaced.

A flow rate detection section 21 is provided in the middle of the discharge piping 5B of the fire pump 1, and this flow rate detection section 21 consists of a dynamic pressure detection section 22 and a static pressure detection section 23 using pitot tubes, and the detected pressure is determined by the pipe line 22A and the static pressure detection section 23, respectively. 23A to both sides of the diaphragm 17A of the first diaphragm device 17. Therefore, the diaphragm 17A handles these differential pressures, that is, the discharge pipe 5B.
displacement in proportion to the flow rate. Note that 24 indicates a pressure gauge.

Next, the chemical pressure downstream of the pressure regulating valve 15 and upstream of the variable orifice 16 is introduced to the diaphragm 18A of the second diaphragm device 18, and the diaphragm 18A is displaced in accordance with this pressure.

Therefore, the rod 19 moves up and down to a position where these diaphragms 17A and 18A are balanced, and the opening degree of the pressure regulating valve 15 changes accordingly.

In addition, 25 is a spring for pressure adjustment, and 26 is a pressure gauge.

A check valve 2 is provided downstream of the variable orifice 16.
7 is interposed to prevent the chemical liquid from being sucked in by the negative pressure generated by the fire extinguishing water that naturally falls down the suction pipe 5A when the fire pump 1 stops driving (therefore, this check valve 27 The maximum cracking pressure is 1Kg/cm ² , which is equivalent to atmospheric pressure.

The structure is as described above, and the operation will be explained next.

As the fire pump 1 is driven, fire extinguishing water is pumped up from a water tank (not shown) to the suction pipe 5A,
Water turret (water cannon) 2 from discharge pipe 5B
be pumped to.

On the other hand, the pressure regulating valve 15 is driven by the chemical pump 4.
From there, the chemical liquid is fed into the low pressure (negative pressure) suction pipe 5A via the variable orifice 16.

Therefore, a chemical solution (foam) is sucked into the fire pump 1 together with the fire extinguishing water, and is pumped to the water discharge turret 2 while being mixed with each other.

The ratio of the chemical solution mixed into the fire extinguishing water is determined by the pressure determined by the pressure regulating valve 15 and the variable orifice 1.
It changes depending on the opening degree of 6.

The opening degree of the variable orifice 16 is set according to the type of chemical liquid to be mixed, and the initial pressure of the pressure regulating valve 15 is adjusted by the spring 25, thereby setting the mixing ratio for the fire extinguishing water.

The amount of water discharged from the water discharge turret 2 is set to an appropriate value as necessary, for example, depending on the rotational speed of the fire pump 1 and the like.

Assuming that a constant flow rate is supplied to the water turret 2 in this way, the flow rate detection unit 21 makes the differential pressure between the detection units 22 and 23 constant, so the first diaphragm 17A remains stationary at that position. However, the rod 19 also does not move, and the opening degree of the pressure regulating valve 15 attempts to maintain a constant value. Therefore, as long as the pressure of the chemical liquid sent from the chemical pump 4 does not change, the flow rate of the chemical liquid passing through the variable orifice 16 does not change, and the mixing ratio of the chemical liquid to the fire extinguishing water is also controlled to be constant according to the opening degree of the orifice.

On the other hand, if, for example, the discharge pressure of the chemical liquid pump 4 decreases even though the discharge flow rate does not change, the pressure in front of the variable orifice 16 will also decrease relatively, the passing flow rate will decrease, and the mixing ratio of the chemical liquid will decrease. Trying to go down.

However, as the chemical liquid discharge pressure decreases, the pressure acting on the second diaphragm 18A decreases, and as a result, the balance with the first diaphragm 17A is lost, and the diaphragm rises upward to a balanced position. Therefore, the opening degree of the pressure regulating valve 15 increases, and in order to reduce the pressure drop at the pressure regulating valve 15, the upstream pressure of the variable orifice 16 is restored.

As a result, a decrease in the mixing ratio of the chemical solution is prevented,
A predetermined mixing ratio set by variable orifice 16 can be maintained.

Conversely, when the discharge pressure of the chemical liquid pump 4 increases, the opening degree of the pressure regulating valve 15 becomes smaller, thereby preventing the mixing ratio of the chemical liquid from increasing.

On the other hand, when increasing the water discharge flow rate, when the discharge flow rate (mixture of fire extinguishing water and chemical solution) from the fire pump 1 increases, the differential pressure detected by the flow rate detection unit 21 increases, and the first diaphragm 17A moves upward in the figure. attempt to displace it.

As the diaphragm 17A moves upward, the valve body 20 is also pulled up via the rod 19, and the opening degree of the pressure regulating valve 15 increases. Therefore, the pressure on the upstream side of the variable orifice 16 increases, and the flow rate of the chemical solution passing through the variable orifice 16 also increases.

However, this pressure is applied to the second diaphragm 18A.
diaphragm 1 as the pressure increases.
8A moved downward, that is, increased pressure regulating valve 1
5 in the original direction, that is, in the decreasing direction, a driving force proportional to the pressure acting on each diaphragm and the diaphragm area ratio acts on the diaphragms 17A and 18A, and the two move to a balanced position. so that the pressure ratio acting on both diaphragms 17A and 18A becomes constant.
The opening degree of the pressure regulating valve 15 is controlled.

As a result, when the overall flow rate increases, the chemical solution flow rate also increases, but since the rate of increase is proportional to the overall flow rate, the ratio of chemical solution to fire extinguishing water remains at the initially set value. .

In this way, the mixing ratio of the chemical solution can always be maintained accurately at the target value.

On the other hand, since the chemical liquid is mixed in on the suction side, that is, the low pressure side, of the fire pump 1, the chemical liquid pump 4 does not need to be a high pressure pump, and only needs to overcome the cracking pressure (1 Kg/cm ² ) of the check valve 27. It is sufficient to generate a discharge pressure of

Further, the flow rate detection section 21 on the discharge side of the fire pump 1 does not require an orifice like the conventional one, and therefore there is little pressure loss.

(Effect of the invention) As described above, according to the invention, the chemical liquid piping from the chemical liquid pump is connected in the middle of the suction piping of the fire pump, and the pressure regulating valve and the variable orifice are interposed in series in the middle of this chemical liquid piping. However, since the chemical liquid is mixed into the suction side of the fire pump, the required supply pressure of the chemical liquid is low, and the chemical liquid pump can be made into a low-pressure, inexpensive type. Since the chemical liquid mixture amount is controlled in proportion to the pump discharge flow rate in response to the detected pressure of the flow rate detection unit installed at ,
The mixing ratio can be precisely controlled.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, and FIG. 2 is a circuit configuration diagram of a conventional example. 1...Fire pump, 2...Water turret,
3... Chemical liquid tank, 4... Chemical liquid pump, 5A... Suction piping, 5B... Discharge piping, 6... Chemical liquid piping, 15
...Pressure regulating valve, 16...Variable orifice, 1
7, 18...Diaphragm device, 19...Rod, 21...Flow rate detection section.

Claims (1)

[Scope of utility model registration request] A chemical liquid pipe from a chemical liquid pump is connected in the middle of the suction pipe of the fire pump, a pressure regulating valve and a variable orifice are interposed in series in the middle of this chemical liquid piping, and the pressure regulating valve is provided in the discharge pipe of the fire pump. It is composed of a member that responds to the detected pressure of the flow rate detection unit and the pressure upstream of the variable orifice, and a valve body connected to this pressure responsive member, and controls the amount of mixed chemical liquid in proportion to the pump discharge flow rate. Characteristic firefighting foam mixing device.