Fine water mist nozzle selection

Water mist nozzles should choose the appropriate model according to the application scenario. For example, according to the working pressure, they can be divided into high-pressure water mist nozzles, medium-pressure water mist nozzles and low-pressure water mist nozzles. The scope of application of these three types of water mist nozzles is different. So how to choose a fine water mist nozzle? It mainly depends on the application site. Of course, closed nozzles are selected for closed water mist systems, while open nozzles are used for open water mist systems or local application systems.

1. Selection requirements for fine water mist nozzles

According to different application places, fine water mist nozzles can be divided into more than 100 kinds of fine water mist nozzles for different occasions, such as open nozzles, closed nozzles, separated nozzles, special nozzles for tall spaces, and ultra-fine water mist nozzles.

① For places where the nozzle holes of the nozzle are easily blocked by external foreign matter, a nozzle with corresponding protective measures that does not affect the effect of fine water spraying should be selected. For dusty places, a nozzle with a dust cover (end cover) should be used, but the spray should not block the spray and cause harm to personnel during spraying.

② For the floor mezzanine of electronic data processing room and communication room, it is advisable to choose a sprinkler head suitable for low space.

③ For closed systems, a nozzle with a response time index no greater than 50 (m.s) 0.5 should be selected. Its nominal operating temperature should be 30°C higher than the maximum ambient temperature, and nozzles with the same thermal performance should be used in the same protection area.

④ For corrosive environments, nozzles made of anti-corrosion materials or anti-corrosion coatings should be used.

⑤ Impact atomization type water mist nozzles should not be used in water mist fire extinguishing systems in places with electrical fire hazards.

2. Principles for selecting fine water mist nozzles

1. When the water mist system is installed in a place containing dust or oil-containing substances, it is easy to cause the nozzle to be clogged. In these places, protective measures such as dust prevention and grease prevention must be considered. These measures must not affect the normal operation of the water mist nozzle in the event of a fire.

Choosing fast-response sprinklers for closed systems can improve the system's ability to control initial fires.

2. Water mist nozzles are generally arranged in a rectangular shape, but some are also arranged in other forms. For an open system, the basic requirement is to evenly distribute the fine water mist and fill the protective space, thus shielding the protected object. For closed systems, the sprinkler head coverage should be clear.

The temperature-sensing element of the closed water mist nozzle is a heat-sensitive glass ball, etc. When arranging the nozzle, its heat collection effect needs to be considered. The distance between the nozzle temperature-sensing element and the top plate must be such that the system nozzle can open in time.

Obstructions located near the water mist nozzle may have an adverse effect on the spray effect of the nozzle, such as preventing the spray from reaching the protected object smoothly or enveloping the protected object. When designing, the obscuring objects must be avoided, or local enhanced protection measures must be taken.

For narrow and long protective areas such as cable tunnels, nozzles can be arranged in a linear manner. Generally, the nozzles are arranged above the aisles of the tunnel. Regardless of the method, it is necessary to confirm that the fine water mist can fill the protected cable tunnel space.

3. When the open system uses local application for protection, due to different products and different protection objects, there is no fixed way to arrange the nozzles. It needs to be designed based on the geometry of the protection object to confirm that the fine water mist can envelope or cover the protection object or part. A minimum distance is required between the water mist nozzle and the protected object to achieve good atomization of the water mist nozzle at this distance. There is also a maximum distance limit required between the water mist nozzle and the protected object to confirm that the spray has sufficient impulse and reaches the surface of the protected object.

The water mist fire extinguishing system is used to protect oil-immersed transformers and is a typical application of local application in open systems.

3. Fine water mist nozzle model

Generally, manufacturers process fine water mist nozzles based on models. The model of fine water mist nozzles usually includes some important technical parameters, such as working pressure, flow coefficient, material, etc. There are many models of water mist nozzles, such as open nozzles, closed nozzles, high-pressure water mist nozzles, medium-pressure water mist nozzles, etc. The models are all different, and often changing one of the parameters will represent different water mist nozzles.

Click to view:What are the models of fine water mist nozzles?

Before choosing a model of a fine water mist nozzle, you need to first determine what type of fine water mist nozzle should be used, such as whether it should be an open type or a closed type, whether it is a high-pressure condition or a medium-low pressure condition. The choice should be based on the actual site environment. In most cases, customers often need to customize water mist nozzles according to the scene. Anhui Lanzhong Electromechanical has the ability to design and produce various types of water mist nozzles to meet the needs of different customers.

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