JPH0510831Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a fire extinguishing foam nozzle.

Conventionally, foam nozzles used in foam fire extinguishing systems collide the foam mixture with a deflector to cause it to scatter and form foam, or to discharge the foam mixture from multiple nozzles and mix it with air to form foam. However, in the former method, the foam mixture collides with a deflector and is scattered, resulting in a large amount of energy loss, shortening the water discharge distance, and making the structure complicated and expensive. Furthermore, since the latter method discharges the foam mixture from a plurality of nozzles, it is difficult to control the flow rate, each nozzle has a small diameter and is easily clogged, and the structure is complicated and expensive.

In view of the above points, this invention aims to provide an inexpensive foam nozzle with a simple structure, and provides a foam nozzle that utilizes the phenomenon of contraction.

The following explanation will be given with reference to Fig. 1 and Fig. 2. In the figures, 1 is a nozzle, pressurized foam mixture is supplied from the left side, 2 is a convergent part attached to the nozzle 1, and 3 is a pipe spear connected to the tip of the convergent part 2 so as to form an air inlet 4. In the convergent part 2, a contraction flow 5 of the flow tube is generated as shown in Fig. 2, and negative pressure is generated on the outer periphery of this contraction flow 5, which causes the liquid to become granular from the outlet of the convergent part 2 and to be scattered toward the pipe spear 3, where it is well mixed with the air flowing in from the air inlet 4 and foamed, and then discharged from the pipe spear 3. In the figures, the case where the inlet angle θ' of the nozzle 1 is 180° is explained, but the contraction phenomenon occurs when this inlet angle θ is 1
This occurs at angles of 16°, as shown by the dashed line, and at angles greater than this up to 360°, and the degree of this phenomenon increases as θ increases, reaching a maximum at θ of 360°. The flow coefficient C of the fluid passing through the nozzle is calculated as the product of the contraction coefficient _Cc of the contraction flow and _the velocity coefficient _Cv . In other words, C = _CcCv .

To further explain contracta flow using Figure 3,
A is for the case where the converging part 2 is not attached to the nozzle 1, and when the inlet angle θ of the nozzle 1 is 16°, a,
The contractions are shown in b for 180° and c for 360°. B
In the case where the converging portion 2 is attached to the nozzle 1, the same as above shows the contracted flow in each case of a, b, and c. C is the same as B in that the convergent part 2 is attached to the nozzle 1, but the condensed flow in each case of a, b, and c is when the length of the convergent part 2 is longer than in B. are shown respectively. As can be seen from Fig. 3, the larger the inlet angle θ of the nozzle 1, the more remarkable the degree of the constriction phenomenon (minimum diameter of the constriction point). Even if 2 is not attached (in the case of A) or even if it is attached (in the cases of B and C), the degree of contraction does not change. However, if the length of the convergent part 2 is set to be sufficiently long as in case C, the fluid after contraction spreads again to fill the pipe of the convergent part 2 and flows. Using the condensed flow 5 in case C, in that case, when θ is 16° or more and the ratio of the length l of the convergent part 2 to its diameter D is l/D≧3, the foam mixture becomes particulate. It was confirmed that good foaming could be obtained.

In addition, as shown in FIG.
is provided and connected to the foam concentrate layer 8 via the conduit 7,
Supplying the fire extinguishing foam stock solution from the stock solution layer 8 under atmospheric pressure,
A foam nozzle with a mixing function is obtained in which the flowing water passing through the contraction point is mixed into fine particles and foamed.

Since the foam nozzle of this invention is constructed and operates as described above, it is possible to process and construct the entire nozzle part of the foam nozzle as an integral part, resulting in a foam fire extinguishing nozzle with a simple structure and less clogging. There is.

[Brief description of the drawings]

Figure 1 is a vertical sectional view of the foam nozzle of this invention, Figure 2
The figure is a vertical cross-sectional view showing the state of the foam mixture flowing into the nozzle in Figure 1, Figure 3 is an explanatory diagram showing the contraction phenomenon, and Figure 4 is a vertical cross-sectional view of the foam nozzle equipped with the mixing function of this invention. It is. 1... Nozzle, 2... Converging part, 3... Tube spear, 4
...Air inlet, 5... Contraction, 6... Small mouth, 7...
... Conduit, 8... Foam stock solution layer.

Claims (1)

[Scope of utility model registration request] a nozzle with an inlet angle ranging from 16° to 360°;
It consists of a straight pipe-shaped converging part that is integrally attached to the nozzle on the exit side of the nozzle, and a pipe lance that is connected to surround the tip of the converging part to form an air inlet, and the length of the converging part is A fire extinguishing foam nozzle characterized in that the relationship between l and D is l/D≧3.