Principle of ZWNS type ultra-low NOx (NOx < 30mg/m3) vacuum boiler）

The boiling point of water at one atmospheric pressure (1bar) is 100˚C. When the pressure is lower than 1bar, the water boiling point is less than 100˚C. For example, when  pressure comes to  0.7bar, then boiling point will be 90˚C. 0.3bar is related to 70˚C boiling point. The pressure is 0.1bar and the boiling point is 40˚C.

 

The closed chamber inside the vacuum hot water boiler forms a vacuum chamber after being pumped through the vacuum. The combustion causes the heat medium water to boil and vaporize in the vacuum chamber to produce negative pressure water steam. The steam condenses outside the heat exchanger tube, and the cold water in the tube atmospheric pressure hot water boiler is heated and heated to the user. The normal working pressure of boiler is less than 0.7bar. Heat medium water is a special treatment of high purity water such as descaling and deoxidation, which is filled by the factory before leaving the factory. When used, it is closed in the boiler (vaporization - condensation - vaporization), does not increase, does not reduce, and does not need to be supplemented or replaced within the service life of the boiler vacuum boiler characteristics.

 

At present, the company's vacuum hot water boilers are divided into ZWNS-Y type fuel oil, ZWNS-Q type gas and ZWNS-D type electric heating vacuum hot water boilers.






FIG. 1 ultra-low Nitrogen Vacuum Hot Water Boiler

1. Safe and reliable

The operating temperature of the unit is lower than 90"C, the working pressure is less than 0.7bar, and the unit is in a negative pressure state, which is safe and reliable. In order to fundamentally ensure the safe operation of negative pressure units, the company has adopted multiple safety protection measures in product design:

A. Temperature protection device: the heat medium water in the boiler furnace is provided with a PT100 temperature sensor probe, and is connected with the PLC electronic controller, when the heat medium water temperature exceeds the set temperature (<99℃), and the burner stops burning the boiler will automatically alarm, or automatically cut off the power supply of the vacuum hot water boiler.

b. overpressure protection device: the boiler body vacuum pressure controller, and connected with the PLC electronic controller, when the internal pressure of the boiler exceeds the set pressure (<0.045MPa), the boiler will automatically alarm, and make the burner stop working or automatically cut off the power supply of the vacuum hot water boiler.

c. Natural gas leak alarm: When the boiler is running, the matching import burner gas leak detection device monitors the amount of gas leakage in the air at any time, and once it exceeds the standard, the gas solenoid valve automatically closes and alarms.

d. Mechanical explosion-proof device: the top of the boiler is equipped with a mechanical overpressure device, when the pressure in the boiler exceeds the maximum pressure design value, the explosion-proof diaphragm in the device will be broken by the top needle and pressure relief, fundamentally ensuring the safety of the boiler body and eliminating the possibility of boiler explosion.

e. water level protection device: when the heat medium water in the boiler furnace body is lower than the set water level for some reason, the device outputs the signal and is connected with the PLC electric controller, the boiler automatically alarms and makes the burner stop working or automatically cuts off the power supply of the vacuum hot water boiler.

2. Multiple use of one machine

Each vacuum hot water boiler can be configured with multiple heat exchangers to meet the different needs of users, such as heating, sanitary water, process hot water and other uses in one at the same time.

3. High thermal efficiency

The combustion mode of the boiler is a wet-back three-pass front smoke chamber structure. The smoke pipe adopts internal and external double thread winding finned tube, which greatly reduces the temperature of the boiler smoke chamber, so that the exhaust temperature of the boiler is 120℃ ± 5℃; The heat exchange tube of the built-in heat exchanger adopts a unique large-pitch threaded tube structure to improve the heat exchanger effect. The overall thermal efficiency of the boiler is more than 94.6%, and the technical performance indicators are far from the domestic leading position, so as to achieve the goal of truly building the first brand of vacuum hot water boiler in China.

4. Simple system, easy installation, low nitrogen, low carbon energy saving

Because the boiler heat medium water is filled once, there is no need to replenish water during operation, so the system does not need to be equipped with external equipment such as water processor, soft water tank, heat exchanger, etc., only need to connect the external pipeline to use, simple installation, low cost, and reduce the floor area of the boiler room. Because the boiler has high thermal efficiency, low operating cost and high degree of automation, it can reduce the configuration of operators, and does not require annual inspection and audit, so the overall operation is simple, convenient and energy-saving.

5. High vacuum, never leak

In the process of product manufacturing, the vacuum leak detection process with independent intellectual property rights (patent No. ZL200920115379.5) is applied to carry out multiple vacuum leak detection processes, so that the leakage index of the product is < 10-10Pa·m3/s, to ensure that the vacuum never leaks after the product leaves the factory.

1. The pressure is less than 1bar, without approval procedures, safe and reliable

2. Has passed the national environmental protection certification, low carbon and low nitrogen, friendly to the environment

3. With a number of independent patents, trustworthy

4. It can realize unmanned remote operation and save human cost