SU1683783A1 - Method of supplying fire extinguishing liquid mixture - Google Patents

Abstract

The invention relates to fire fighting technology and is used to meter and supply multi-component liquid fire extinguishing compositions to a fire extinguishing system. The purpose of the invention is to increase the fire extinguishing efficiency by expanding the range of application in terms of the number of components and increasing the metering accuracy. The containers are filled with components to the same level, the components are dispensed simultaneously with the flow of the liquid composition into the fire extinguishing system, and the components are metered in an amount determined from the ratio to which the input parameters take into account the hydraulic characteristics of the supply lines of the components and the total liquid composition flow. . 1 ill., 1 tab.

Description

The invention relates to fire fighting equipment and is used to form, meter and supply multicomponent liquid fire extinguishing mixtures to fire extinguishing systems.

The purpose of the invention is to increase the efficiency of fire extinguishing by expanding the range of use by the number of components and improving the metering accuracy.

The drawing shows the dosing scheme and the supply of a multicomponent composition to the fire extinguishing system. It includes the first number of containers for storing the liquid components that form the liquid mixture to extinguish the fire. Equal in height d tanks fill proportionally with concentration on the basis of

WI-Qr-W (Ki + Kz-K..Ki-i). (1) where Q - feed mixture.

All the tanks, placed on the axle of the pump 1, are connected to the suction inlet 2 via self-contained lines 3, f, 5 for supplying components 1, 2 ... I. On these lines are shut-off and start-up units b, 7, 8 and metering devices 9.10,11. In a room where a fire can occur, there is a fire detector 12 with a signal converter 13 and a pulse transmission line 14 for simultaneous activation of elements of the fire extinguishing system 15 of shut-off / start-up units of component 6, 7, 8 of pump 1 and the main start-up unit 16. ,

with,-

Oj x

The dosing of the components and the supply of the liquid mixture to the fire extinguishing system are as follows. To extinguish a fire, it is necessary to supply a liquid mixture containing the first number of components of the required concentration. For this capacity, 17–19 for storing 1, 2, ... i-ro components is filled to the same level.

In the event of a fire, the fire detector 12 reacts to one of the fire factors (temperature, smoke, etc.), its signal through the converter 13 is transmitted via the pulse supply lines 14, to simultaneously turn on the pump -1, the stop and start nodes 6, 7, 8 and the control unit 15. In the suction line 2 of the pump 1, the discharge develops and each of the 1.2., 1-components under the action of the hydrostatic head (Z) flows through the metering devices 9, 10 into the pump 1 .

For illustration, an example of a method for metering and supplying a three-component fluid is considered.

As a result of the research, it was found that the highest efficiency of the fire extinguishing system is achieved when dosing and supplying a liquid mixture containing the following component concentrations: water — 0.93; foam former PO-1-0.06; polyacrylamide - 0.01. The fire extinguishing effect of the foam obtained from the above liquid mixture does not change with an absolute error in the formulation of the liquid mixture for each component equal to ± 10%. With an error of ± 50%, the fire extinguishing effect is halved, with an error of 100% the fire extinguishing effect of the foam disappears.

To ensure the required accuracy of dosing each of the three components of the liquid mixture in accordance with the proposed method, it is necessary: when forming the charge of the liquid mixture, the components in the tank should be filled to the same level; determine by calculation the hydraulic resistance of the selection lines of the components; establish the degree of opening of the metering devices corresponding to the design hydraulic resistance; to carry out the simultaneous selection of all components of the liquid mixture when the fire extinguishing system is turned on.

With this method, automatic dosing of each of the components is achieved in an amount proportional to its concentration, the value of which is determined by the m3 ratio:

(Ki + K2 + - - + l | -1) (1)

where t is the duration of the liquid mixture;

Wj-volume i-ro component;

h - pressure loss in the component selection lines (h const);

Si is the flow resistance of i-ro components;

Ki, K2 ... Ki - concentration of 1,2 ... i-ro components of the liquid mixture.

The calculation algorithm is as follows: the values are given: g, Wi, KI, and dosing accuracy with an accuracy of KI ± 0.1 KI; Formula 1 is substituted for such values of SIH at h const (e.g., 5 m), at which the condition of dosing accuracy is KIH KI ± 0.1 Ki; the numerical value thus obtained is substituted into the formula

S. 0.0827 0 | 0 (LD + A), (2)

from which, according to the assortment, the closest to the calculated pipeline diameter is the extraction line of the 1st component for the given parameters d, / 3i and fl (density, viscosity, hydraulic friction); Ar is the coefficient of hydraulic friction; from (2) one finds such a metering device (for example, a cork valve, a valve, a butterfly valve), by changing the degree of opening of which a value fi is obtained, a coefficient taking into account the viscosity at which Si SiH.

The table shows the results of calculating the value of K by the formulas (1) and (2) for the proposed method and the prototype.

From the table it can be seen that when connecting the components to the pump through equal-to-diameter d 100 pipelines for the selection of components will occur with an equal concentration K K - 0.38. Such a solution gives an unacceptable dosing error of 64% to ± 99%. With such an error, the desired fire extinguishing effect is not achieved. When using the inventive method, the metering error is zero.

To illustrate the method, we consider the second example of the supply of a two-component liquid (a percentage solution of the foaming agent PO-1) to the installation of a water-foam fire extinguishing. For the calculation, the foaming agent viscosity is taken, vi 4,8 vz- 0,983; frother density p -1.05: jQ2 1.0, kg. 0.05; KV 0.95; W 18 Om3.

The dosing error of the frother when the parameters recommended by the method deviate is estimated by the value

Kn - Kn

D

ky

where KP is actual, and KP is the standard flow of a frother:

 1.5 1.0 0.5 0.3

KV0.93 0.94 0.95 0.965 0.973

Kp0,07 0,06 0,05 0,035 0,027

A + 0.40 +20 0 -30 -46

The metering error of the foaming agent when the hydraulic resistance deviates, S from the standard value of SH (at fixed g and 5H): 5 / 5n 2 1.5 1.0 0.5 0.3 Kv 0.965 0.959 0.95 0.93 0.9 Kp 0.035 0.041 0, 05 0.070.09 A -30. -20 0 +40 +80

The dosing error of the foaming agent in case of deviation of the duration of the switching on of the supply of Ag from the duration of the operation of the fire extinguishing installation g (with standard and fixed 5H and

Zn):

AG / THO 0.1 0.2 0.3 0.4 0.4 0.5.

square 0.95 0.955 0.96 0.965 0.97 0.975

kp 0.05 0.45 0.04 0.033 0.03 0.025

A About -10 -20 -30 -40 -50

 With the simultaneous influence of the above factors, for example, 0.3; S / SH 2; Ar / g 0.5 O / He value 0.2, i.e. The fire extinguishing system will not be supplied with a 5% solution, but with a 10% aqueous solution of the frother. This will lead to an almost complete loss of the extinguishing effect, since no foam is formed from this solution.

Thanks to the proposed method, there is no need to use an ejector, a regulator and a flow meter, which makes it possible to reduce the installation capacity of the pumping unit and capital investments on the construction of the pumping station.

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Claims (2)

Invention Formula The method of supplying the liquid mixture for fire extinguishing, including preparing the mixture of components and filling the tank to the same level, selecting components from the tanks simultaneously with supplying water to the discharge pipe of the fire extinguishing system, dispensing them with mixing and feeding the mixture of components to the discharge pipe of the fire extinguishing system, that, in order to increase the fire extinguishing efficiency by increasing the dosing accuracy, the dosing of each component is carried out in an amount proportional to their concentration concentration, the value of which is determined from the ratio (.. + k, -1), where W is the total volume of the 1st component composition; g - the duration of the submission of the composition; h is the pressure loss in the component supply line; ft, A og the flow resistance of the 1st component: a - coefficient taking into account the density of the 1st component; $ is the coefficient taking into account the viscosity of the 1st component; D is the coefficient of hydraulic friction; Јi is the coefficient of local resistance of the supply line of the 1st component; 11 is the length of the supply line of the 1st component; di is the diameter of the supply line of the 1st component; Ki, K2 ... Ki-i - concentration 1, 2..L components in the composition (in shares x units). Si 0.0827 o # (A + C-) - hydraulic- dr HP I fc 12 15 6 T sixteen