Physical characteristics

Both electrode type and electric heating type steam humidifiers belong to isothermal humidification, and the dry bulb temperature slightly increases during humidification.

When used in conjunction with an air handling system, there is no need to preheat the air to a higher temperature.

Both types of steam humidifiers have high humidification efficiency, both of which are above 95%.

Power consumption

The power consumption of both types of steam humidifiers is 1kg/h, and the power consumption of steam production is 750W (380V).

For example, with a humidification capacity of 40kg/h, whether it is an electrode type or an electric heating type, its power is 30KW. 40 * 0.75=30KW

Control accuracy

The control accuracy of the electrode steam humidifier is+5%.

The control accuracy of the electric steam humidifier is 2-5% (depending on the control method and conditions).

Operational principle

1. Working principle of electrode type steam humidifier

When water exists in pure water form, it is non-conductive. The reason why tap water used in daily life can conduct electricity is because there is a large amount of mineral salts present in the water. The working principle of electrode type steam humidifiers is to utilize the conductivity of water.

When water containing mineral salts enters the humidifying bucket through the inlet valve, the electrode plates on the upper part of the humidifying bucket will gradually immerse in the water as the water level gradually rises. Since water containing mineral salts is a conductor, a path will be formed when the water contacts the electrode plates. At this time, we apply electric pressure to the electrode plates, and the ions in the water will move at high speed, generating heat energy through friction, causing the water to heat up and generate clean saturated steam, Then, it is fed into the air conditioning box or duct through a steam diffusion device to achieve the purpose of humidification of the air.

According to the Joule effect, the steam output is proportional to the current, and then to the water level. This current is measured through a current transformer and is repeatedly opened and closed by the inlet and outlet valves to adjust the water level. The current and steam output are precisely adjusted.

During evaporation, the water level will decrease, but the steam cannot carry away the mineral salts in the water. As a result, the concentration of mineral salts in the water will increase, leading to an increase in conductivity. Once the current reaches the upper limit set by the microprocessor control, the drain valve will discharge high concentration water, and then add new water through the inlet valve to achieve dilution, thus protecting the humidification bucket. The scale generated by long-term operation will adhere to the electrode plate, blocking the contact between the electrode plate and the ions in the water, thereby affecting the humidification amount. Therefore, the humidification bucket should be cleaned and replaced regularly.

2. Working principle of electric steam humidifier

After heating pure water with the heat generated by electrification using a resistor to generate water vapor, the steam is distributed through the steam distribution pipe in the air conditioning box or duct for air humidification.

The main action mode is to control the operation of a single or multiple sets of electromagnetic relays or SCR thyristor rectifiers by the control box according to the humidification demand, in order to control the heat production of the electric heating tube and generate the required humidification amount.

Electric heating tubes are the core components, and their stability, service life, and reliability are very important.

The production method of an electric heating tube is to evenly distribute high-temperature resistance wires in the middle of a high-temperature resistant stainless steel tube, and densely fill the gaps around it with crystalline magnesium oxide powder with good thermal conductivity and insulation performance. This structure not only serves to fix the resistance wires, but also has high thermal efficiency and uniform heating. When there is current passing through the high-temperature resistance wire, the generated heat energy is transmitted to the surface of the metal tube through crystalline magnesium powder, and then pure water is heated to generate steam through thermal conduction and convection, followed by air humidification.

Electric heating tube	Evaporation water tank

Usage conditions

1. Power supply:

380V, three-phase five wire

2. Water supply requirements:

Water pressure 2~6Bar, water temperature 4~40 ℃

The electrode type steam humidifier requires municipal tap water, with a conductivity of 100-300 micro Ximen being the best.

Electric steam humidifiers require pure water, also known as deionized water.

Acquisition cost

The cost of electric heating is about 2.5 times that of electrode heating for the same humidification demand.

Humidification knowledge

1. What are the hazards of scale on electric steam humidifiers?

※ Slow heating up

The calcium and magnesium ions contained in water react chemically to form carbonate scale, sulfate scale, silicate scale, and mixed scale (salt scale and scale) at a certain temperature (water temperature exceeds 60 ℃, the faster the scaling rate). These substances have poor thermal conductivity, and adhering to the wall of the electric heating tube can reduce the energy conversion between energy and water. Many of the heat is blocked by scale, resulting in a decrease in heating speed and a sharp decrease in heating speed.

※ Corrosion electric heating tube

In addition to strong heat resistance, scale also has a certain degree of corrosiveness. The scale adheres to the surface of the electric heating tube, causing the protective layer of the electric heating tube to rot, resulting in rust and copper green on the electric heating tube. The longer the scale adheres, the more corrosive it becomes, making it difficult to clean the surface of the electric heating tube. Moreover, due to the heat resistance caused by scale, the local temperature of the electric heating tube adhered to the scale is getting higher and higher, and finally it breaks through the wall of the electric heating tube, causing the tube to explode.

※ Energy consumption

The thermal conductivity of scale is poor, which can affect energy exchange and result in high energy consumption.

※ Safety hazards

Scaling can cause electric heating tubes to burst, leading to some secondary safety hazards.

2. Why can only pure water be used instead of softened water when using an electric steam humidifier?

Generally, water supply contains a large amount of calcium and magnesium ions. Softened water and pure water are both water treatment methods. The former mainly uses ion exchange method to soften the hardness of the water, which not only has the issue of exchange efficiency, but also has the problem of leakage in practical use, which cannot completely remove calcium and magnesium ions in the water. The latter directly removes calcium and magnesium ions in the water through RO membrane.

The diameter of calcium ions is 0.0004 microns, the diameter of magnesium ions is 0.0005 microns, and the filtration accuracy of RO membrane is 0.0001 microns.

The filtration accuracy of ultrafiltration membrane is 0.01 micrometers, and the commonly used ordinary water filters on the market generally have a filtration accuracy of around 5-50 micrometers.