Working Principle and Product Structure of Humidifiers

A humidifier is a device that increases air humidity through physical or chemical means. Its working principle and product structure vary significantly depending on the type. Common types include ultrasonic humidifiers, electric heating humidifiers, evaporative humidifiers, and high-pressure spray humidifiers. The following sections provide detailed explanations from both core principles and structural perspectives:

1. Working Principle of Humidifiers

Different types of humidifiers use various technological approaches to convert water into vapor and disperse it into the air, with the core goal of increasing the relative humidity of the environment (typically maintained within the comfortable range of 40%-60%).

1.1 Ultrasonic Humidifier (Mainstream for Home/Commercial Use)

Principle: High-Frequency Vibration Atomizes Water

• Utilizes an ultrasonic vibrator (transducer) to generate high-frequency mechanical vibrations at 1.7-2.4 MHz, breaking water in the tank into ultrafine droplets (aerosols) with diameters of 1-5 micrometers. A built-in fan then blows these droplets into the air, where they quickly evaporate to increase humidity.
• Features: High atomization efficiency (0.2-3 liters per hour), no high-temperature components, low noise, suitable for home bedrooms, offices, and similar environments.

1.2 Electric Heating Humidifier (Commonly Used in Medical/Industrial Settings)

Principle: Heating Water to Boiling Produces Steam

• Uses a heating tube or heating plate to heat water in the tank to boiling, producing pure water vapor (gaseous water). The steam naturally diffuses or is directed through pipes into the air to directly increase humidity.
• Features: Produces sterile steam (due to high-temperature sterilization), provides stable humidity increase, suitable for medical ventilators, infant rooms, and other settings requiring high cleanliness. However, it consumes more energy and requires precautions against burns.

1.3 Evaporative Humidifier (Mist-Free Type, Healthy Option)

Principle: Natural Evaporation for Humidification

• Divided into wet membrane type and cold evaporation type, both leveraging the principle that "the larger the contact area between water and air, the faster the evaporation":
  • Wet Membrane Type: A water pump delivers water to the surface of a porous wet membrane (e.g., paper or fiber membrane). A fan draws dry air through the membrane, where water naturally evaporates into the air stream and is discharged.
  • Cold Evaporation Type: A filter (e.g., activated carbon, antibacterial cotton) absorbs water. A fan directs air through the filter, where water evaporates into the environment, and the filter also removes impurities from the water.
• Features: No "white mist," provides natural and gentle humidity, suitable for those sensitive to water quality or with respiratory conditions. However, humidification efficiency is significantly affected by ambient temperature and airspeed.

1.4 High-Pressure Spray Humidifier (Industrial/Large-Area Applications)

Principle: High-Pressure Atomization of Water

• Uses a high-pressure plunger pump to pressurize water to 30-70 bar, which is then sprayed through ultrafine nozzles (aperture 0.1-0.5 mm) to form droplets with diameters of 5-50 micrometers. These droplets quickly evaporate or disperse in the air, enabling large-area humidification.
• Features: Wide coverage (a single unit can cover hundreds of square meters), high humidification capacity (up to tens of liters per hour), suitable for industrial workshops, warehouses, greenhouses, and other large areas. Requires water filtration systems to prevent nozzle clogging.

2. Product Structure of Humidifiers

Structural differences among humidifier types are primarily reflected in the "core humidification module," but overall, they can be divided into basic structure and core functional components.

2.1 Universal Basic Structure (Common to All Types)

• Housing: Protects internal components, typically made of ABS plastic or metal, designed with air inlets and outlets (or spray ports).
• Water Tank/Water Supply System: Stores or delivers water. Home models often feature detachable tanks (capacity 1-5L), while industrial/medical models may include external water pipes (for continuous supply) and water level sensors (to monitor water volume).
• Control Panel and Display: Used to adjust humidity levels, fan speed, timer functions, etc. Smart models support touch controls or remote control via an app, with displays showing current humidity, water level, and other statuses.
• Safety Devices:
  • Dry-Burn Protection: Automatically cuts power when water levels are too low (essential for electric heating and ultrasonic types).
  • Overheat Protection: Shuts down when the heating module or motor temperature is too high (for electric heating and high-pressure pump models).
  • Leak Detection: Sensors at the base detect leaks and trigger alarms or shutdown (for continuous water supply models).

2.2 Core Functional Components by Type

(1) Ultrasonic Humidifier

• Ultrasonic Vibrator (Transducer): Installed at the bottom of the tank, this core component converts electrical energy into high-frequency mechanical vibrations to break water molecules.
• Atomizing Plate: A wear-resistant thin plate (e.g., ceramic) covering the vibrator to prevent direct contact with water and refine droplets.
• Fan and Air Duct: Located above the atomizing plate, these components blow droplets out through the spray port. Duct design affects droplet dispersion and noise levels.
• Water Filter: Some models include built-in filters or ion-exchange resins to reduce calcium and magnesium ions in water.

(2) Electric Heating Humidifier

• Heating Module: Core components include heating tubes (metal) or heating plates (quartz), which generate heat to warm water.
• Temperature Controller: Monitors water temperature, maintaining stability after boiling (to prevent dry burning). Some medical models precisely control steam temperature (37-40°C to match respiratory tract temperature).
• Steam Export Pipe: Specific to medical models, this sterile pipe connects to ventilators or masks to avoid secondary contamination.

(3) Evaporative Humidifier

• Wet Membrane/Filter: Core humidification media. Wet membranes often have a honeycomb structure (to increase contact area), while filters may include antibacterial materials (e.g., silver ions) for both humidification and purification.
• Water Pump/Absorbent Cotton: Delivers water from the tank to the top of the wet membrane/filter, evenly wetting the media via gravity or capillary action (pumps for wet membrane types, absorbent cotton for cold evaporation types).
• Centrifugal Fan: Provides steady airflow to accelerate water evaporation from the membrane surface. Fan power determines humidification efficiency.

(4) High-Pressure Spray Humidifier

• High-Pressure Plunger Pump: Core power component that pressurizes water, determining spray pressure and atomization效果.
• Ultrafine Nozzles: Evenly distributed along pipes or spray bars. Smaller nozzle apertures produce finer droplets (requires water filtration to prevent clogging).
• Piping System: Pressure-resistant pipes (e.g., high-pressure hoses) connect the water tank, pump, and nozzles, with some models including valves to control spray areas.
• Water Treatment System: Pre-filters (remove sediment and impurities) and water softeners (reduce water hardness) extend the lifespan of pumps and nozzles.

3. Summary of Core Structure and Principle Relationships

The core function of a humidifier is the transformation of "water → water vapor," with structural design optimized for this process:

• Ultrasonic/High-Pressure Spray types use physical fragmentation to convert water into fine droplets, relying on vibration or pressure components.
• Electric Heating types use heating and phase change to convert water into steam, relying on heating and temperature control components.
• Evaporative types achieve humidification through natural diffusion, relying on media and airflow components.
  Understanding principles and structures helps in selecting the right model for specific scenarios (e.g., ultrasonic/evaporative for home use, electric heating for medical use) and guides maintenance (e.g., regular cleaning of atomizing plates, replacing filters).