Measuring injection type foam proportion mixer

Abstract

The invention provides a measuring injection type foam proportion mixer which comprises a flow meter, a foam proportion controller, a frequency converter, a variable frequency motor, a plunger pump and the like. The flow meter is used for metering the water flow in a pipeline, and the controller is used for reading the water flow and injecting the required foam into a water flow pipeline by a mixture ratio-setting metering-controlling transporter, so that a measuring injection type foam proportion mixing function is achieved. The measuring injection type foam proportion mixer is applicable to a type A foam fire-fighting system and a type B foam fire-fighting system, wide in allowed flow range, free to set the foam mixing ratio, applicable to various foams, and convenient for the practical operation in a fire-fighting site; and the measuring injection type foam proportion mixer is very high in precision since the mixture ratio is constant regardless of the change of the usage amount of the foam once the mixing ratio is set.

Description

technical field [0001] The invention relates to a metering injection foam proportional mixing device, in particular to a metering injection foam proportional mixing device capable of real-time control and constant foam mixing ratio and suitable for various foam fire extinguishing systems. Background technique [0002] The current fixed foam fire extinguishing system mainly adopts pressure foam proportional mixing device and balanced foam proportional mixing device. The core components of mixing foam on the two kinds of foam proportional mixing devices are Venturi tubes. When the solvent (water) flows through the Venturi tube, the reduction of the local diameter of the Venturi tube will increase the solvent flow rate. From the Bernoulli equation, it can be seen that the inner side of the pipeline in the acceleration section will generate a negative pressure, which will suck the solute (foam liquid) and mix it with the solvent to form a mixed liquid. There are following defec...

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Problems solved by technology

[0003] 1. The foam ratio cannot be accurately obtained, and it is only suitable for Class B foam systems with a mixing ratio of 3% or 6%, but not for Class A foam fire extinguishing systems with a mixing ratio of 0.3% to 1%.

[0004] 2. The shrinkage section in the Venturi tube will cause pressure loss during the solvent delivery process. The greater the negative pressure required, the greater the solvent pressure loss must be

[0005] 3. The allowable flow range of the proportional mixing device is small, and when the solvent flow rate is small, the negative pressure decreases, resulting in the solute (foam liquid) may not be able to enter the solvent, and the precise foam mixing ratio at small flow rates cannot be guaranteed

[0006] 4. The foam mixing ratio is set through the decompression orifice at the inlet of the solute (foam liquid). Once the equipment is installed, it is difficult to adjust the mixing ratio in real time, which makes it difficult to change the foam type suitable for the foam ratio mixing device.

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