Detailed structure of a thermal fog pesticide sprayer

What is a thermal fog pesticide sprayer?

Over the past few years, thermal fog sprayers have become widely used in agriculture, pest control, and large-scale sanitation. But what exactly are they, and why use fog instead of liquid spray or mist?

A thermal fog sprayer is a machine that uses high temperature to vaporize a liquid solution into dense fog or smoke. The fog particles are then dispersed into the air to kill insects, pests, or harmful microorganisms. This device works based on thermal decomposition and pressure, allowing the particles to spread widely and cling longer to plant surfaces or treated areas.

Applications of thermal fog sprayers

Unlike mist or pressure sprayers, thermal foggers can cover large areas using minimal chemical solution, as they produce ultra-fine droplets (typically under 50 microns). They are ideal for spraying in open environments or for deep penetration into plant canopies and narrow spaces such as rice fields, fruit orchards, greenhouses, warehouses, and livestock barns.

Among the most common types is the thermal fogger, used for mosquito and insect control in cities, hospitals, schools, and households. These machines can work with various specialized solutions - pesticides, disinfectants, insecticides, or antibacterial agents. Depending on the model, some sprayers include adjustable fog flow, droplet size selection, or compatibility with multiple fuel types.

Structure and components of a thermal fog sprayer

To understand how efficiently these machines work, we must first look at their internal structure. Each component plays a distinct yet interconnected role, ensuring that fog generation and dispersion remain stable, safe, and effective.

Chemical tank

This tank holds the liquid solution, typically made of stainless steel or aluminum alloy for corrosion and heat resistance. Capacity ranges from 5–20 liters, depending on the model. Some tanks include anti-spill valves and safety-lock caps for user protection.

Engine and combustion chamber

The core of the sprayer is its combustion engine (usually gasoline-powered or spark-ignition). The combustion chamber heats the chemical delivery tube, vaporizing the liquid into fog. The temperature in this section can reach 300°C–600°C.

Pressure and delivery system

A manual or automatic pump generates pressure to push the liquid from the tank into the combustion tube. These tubes are made of heat- and chemical-resistant materials to maintain pressure and distribute the solution evenly during operation.

Nozzle and diffusion head

The nozzle is usually made of heat-resistant metal or a widened diffuser design that prevents clogging and ensures fast, uniform fog dispersion. Some machines feature Venturi nozzles to increase airflow speed and produce finer fog particles.

Flow and safety controls

This unit regulates the spray flow, duration, and in advanced models, the spray angle. High-end sprayers may have automatic shut-off valves, emergency switches, and temperature sensors to prevent overheating or engine overload.

Classification of thermal fog sprayers

Thermal fog sprayers vary by working principle, power source, and intended use. Understanding these differences helps users choose the right model for maximum performance and cost efficiency.

By working principle

• Thermal foggers: Use high heat to vaporize the chemical. Operate on gasoline, LPG, or electric ignition. They provide strong diffusion, ultra-fine droplets, and excellent coverage but require careful temperature control to avoid overheating or waste.
• Cold foggers (ULV – Ultra Low Volume): Although sometimes called “foggers,” these create cold mist droplets (10–50 microns) using a motorized fan. They require no heat, are safer, odorless, and better suited for indoor environments.

By power source

• Gasoline/Diesel sprayers: The most common for agricultural use due to their strong output and mobility. However, they are heavier and noisier.
• Electric sprayers (battery or plug-in): Lightweight and easy to use, ideal for small spaces like greenhouses or animal barns, but limited by battery life or power supply availability.

By application

• Agricultural pest control: Used in fields, orchards, and plantations. Large-scale models can also integrate with agricultural drones for expanded spraying coverage.
• Public health and insect control: Common in cities, hospitals, and schools.
• Disinfection and sanitation: For cleaning barns, warehouses, or food-processing facilities.

Where to buy quality thermal fog sprayers in Vietnam

When purchasing a thermal fog pesticide sprayer, it’s crucial to choose a reputable supplier to ensure machine safety, warranty, and genuine spare parts. Among the trusted distributors in Vietnam, Đại Lợi stands out for offering a full range of agricultural sprayers and drone-based spraying equipment, including thermal foggers, ULV cold foggers, and high-pressure sprayers. With professional technical support, operator training, and nationwide after-sales service, Đại Lợi has become a reliable partner for farmers and agricultural cooperatives seeking efficient pest-control solutions.

Advantages and disadvantages of thermal fog sprayers

Advantages

• High diffusion efficiency: Dense fog penetrates deep into canopies and small crevices, killing insects more effectively than mist or water spray.
• Chemical savings: Uses 30–50% less pesticide while covering large areas.
• Fast operation: Can treat thousands of square meters within minutes, ideal for emergency pest or disease outbreaks.
• Versatile applications: Suitable for agriculture, health, or sanitation; compatible with handheld, vehicle-mounted, or drone-assisted systems.

Disadvantages and risks

• Fire hazard: High operating temperatures and flammable fuel pose safety risks if maintenance is neglected.
• Air pollution and odor: The smoke can cause respiratory irritation; operators must wear proper protection.
• Uneven distribution risk: Inaccurate adjustments may cause over- or under-spraying in some areas.
• High initial cost: Quality foggers range from a few million to several tens of millions VND, excluding fuel and maintenance.

Real-world applications

In agriculture and crop production

• Ideal for fruit orchards (mango, orange, pomelo, durian) with dense foliage.
• Effective for rice fields, vegetables, and industrial crops like pepper, coffee, and cashew.
• The fog penetrates leaves, eliminating eggs, larvae, and adult insects.

In livestock and warehouse sanitation

• Disinfects pig, poultry, and swiftlet farms; removes bacteria and mold in grain storage.
• Specialized fog disinfectants help clean air in enclosed areas.

In public health pest control

• Used for mosquito and fly control in urban, hospital, and school settings.
• Suitable for large-scale vector control during disease outbreaks.

Value for users

• Reduces chemical and labor costs.
• Improves productivity by saving time.
• Enhances farm hygiene and reduces pesticide residue when used properly.

Role in integrated pest management (IPM)

• Acts as a critical tool in IPM systems, combining with biological traps, microbial pesticides, and sustainable farming practices.

Common misconceptions about thermal fog sprayers

“More smoke means higher effectiveness.” - False.

Fog is just a carrier; excess smoke wastes chemicals and can harm crops.

“Any chemical can be used in a fogger.” - False.

Each machine has compatibility limits. Using the wrong solution may clog the nozzle or produce toxic gases.

“No need for safety gear.” - Dangerous mistake.

Fog particles can still contain chemicals; always wear goggles, gloves, and a mask.

“All foggers are the same-cheaper is better.” - False.

Low-quality machines may leak, overheat, or even explode due to poor combustion chambers or seals.

Comparison: Thermal fog vs other sprayer types

Criteria	Thermal fogger	Cold fogger (ULV)	High-pressure sprayer
Droplet size	5–30 microns	10–50 microns	50–100 microns
Working principle	Heat vaporization	Motorized atomization	Pump pressure
Diffusion power	Very strong, wide coverage	Good for indoor use	Limited in open areas
Chemical consumption	30–50% lower	Moderate	High
Safety level	Requires heat control	High	Safe but leaves moisture
Typical uses	Agriculture, mosquito control, outdoor disinfection	Offices, warehouses, greenhouses	Small gardens, livestock
Approx. price (VND)	5–20 million	3–10 million	2–8 million
Mobility	Medium (fuel required)	High	High

When to choose which:

1. Thermal fogger: For large areas, dense canopies, or severe pest infestations.
2. Cold fogger (ULV): For indoor or residential use, prioritizing safety and low odor.
3. High-pressure sprayer: For small-scale, wet spraying tasks.

Conclusion

Understanding the structure and operation of thermal fog sprayers helps ensure proper selection, safer usage, and higher efficiency. From combustion design to application principles, these machines are vital in modern agriculture and disease control.

In the future, combining fogging technology with automation, drones, and AI navigation could significantly advance plant protection and agricultural efficiency.

Quick FAQs about thermal fog sprayers

How long does the chemical remain effective after fogging?

Depending on the formula and environment, 3–7 days. Sunlight or rain may shorten this period.

How often should a fogger be serviced?

Clean the combustion chamber and nozzle after each use; inspect spark plugs, valves, and tubing every 30–50 hours.

Can biological pesticides be used in foggers?

Yes, but only heat-resistant formulations. Use machines with adjustable or low-heat settings.

How to calculate the right chemical dosage?

Follow label dilution rates and adjust slightly based on area size, canopy density, and wind speed.

What are signs of poor performance?

Weak fog output, large droplets, strange noises, burnt smell, or oil leakage - all indicate clogging or engine failure.