Selection and Technical Parameters

1. Selection

The type and quantity of foam generators installed in oil tanks are determined through calculation based on the tank capacity, type of stored oil, size of the oil surface, and the type of foam. However, there must be at least two, each supplied by a separate firefighting pipeline to provide foam mixture.

When the foam mixture flow supplied by the fixed fire pump of a foam fire truck passes through the generator via the delivery pipeline, it forms air foam to extinguish oil fires. There are generally four models: PC-4, PC-8, PC-16, and PC-24.

2. Technical Parameters 

① Model PC-4: At a working pressure of 0.5MPa, the mixture flow is 4 L/s, and the foam generation capacity is 25 L.

② Model PC-8: At a working pressure of 0.5MPa, the mixture flow is 8 L/s, and the foam generation capacity is 50 L.

③ Model PC-16: At a working pressure of 0.5MPa, the mixture flow is 16 L/s, and the foam generation capacity is 100 L. 

④ Model PC-24: At a working pressure of 0.5MPa, the mixture flow is 24 L/s, and the foam generation capacity is 150 L.

3. Working pressure range: 0.2-0.5MPa.

4. The glass disc breaks under a pressure of 0.1-0.2MPa.

5. Specifications and Models

Structural Principle

The air foam generator mainly consists of three parts: the shell assembly, the foam spray pipe assembly, and the guide plate assembly.

When the foam mixture flows through the generator nozzle, it forms a diffused atomized jet, creating negative pressure around it, which draws in a large amount of air to form air foam. The air foam is then delivered into the storage tank through the foam spray pipe and guide plate, flowing down along the tank wall and smoothly covering the burning liquid surface. 

The air foam generator consists of the following parts:

1. Sealing glass 2. Glass retaining ring 3. Nozzle 4. Filter screen 5. Cover plate 6. Shell 7. Foam spray pipe assembly 8. Shell assembly 9. Guide plate assembly

Usage Instructions

The rated working pressure at the inlet of the air foam generator is 0.5MPa, but it can also be used within a pressure range of 0.3–0.5MPa, though the mixture flow and foam generation capacity will vary accordingly.

This generator is equipped with 3% and 6% standard air foam liquid.

To prevent the evaporation and leakage of gas from the flammable liquid storage tank, a sealing glass must be installed at the outlet end of the shell. This glass has fracture lines on one side and can be shattered under a mixture flow pressure of 0.1–0.2MPa. The side with the fracture lines should face the spray outlet during installation.

The guide plate is installed on the inner wall of the storage tank to ensure that the foam flows down along the tank wall and smoothly covers the burning liquid surface, thereby improving fire extinguishing efficiency.

The inlet pipe diameter of the air foam generator must not be smaller than the specified size.

Installation and Maintenance

The air foam generator comes with a product nameplate indicating the product name, model, specifications, manufacturing date, and manufacturer. Before installation, the foam spray pipe assembly must be configured according to the product model.

First, install the guide plate assembly on the inner wall of the storage tank, then install the foam spray pipe assembly and the shell assembly, with the cover plate facing upward.

After installation, perform a foam spray test to observe whether the foam spray is normal, whether the water pump supply pressure and the generator inlet pressure meet requirements, and whether there are any leaks in the pipeline. Finally, install the sealing glass.

The entire pipeline of the air foam generator must remain unobstructed. Regularly check for any blockages and ensure the sealing glass is intact.

To avoid or mitigate damage to the pipeline caused by deformation of the storage tank wall, it is advisable to install a section of metal hose of the same diameter in the inlet pipeline of the generator.