What is a three-pass boiler?

Three times into the structure of a series of automatic oil gas fired steam boilers, are using waveform furnace, flue gas three return, all wet back structure. The fuel is burned in the furnace with a slight positive pressure. The high-temperature flue gas furnace gallbladder enters the first tube bundle through the back-combustion chamber and is forced through the compression type front cigarette box and turns 180° into the second tube bundle. After convection heat exchange, it is discharged into the atmosphere. Using the symmetrical design concept of the center, a three-pass steam boiler with a large capacity is designed.

three pass gas fired boiler

The biggest features of three-pass boiler:

All the pressure elements are symmetrical with the center of the drum. The boiler adopts a fully wet back structure with a large inner cylinder and an eccentric fire box structure, which is conducive to providing a sufficient radiation heating surface. The convective heating surface consists of a tube bundle with a second return stroke and a third return stroke. The front tube plate of the back firing chamber is butt-jointed with the side of the furnace plate, and the rear tube plate of the back firing chamber is connected with the simplified rear tube plate by means of the rear pull support. The second return trip and the third return trip constitute a front smoke box, where the smoke temperature has fallen below 500°C. Therefore, the structure of the front smoke box adopts a lightweight structure of fire-resistant insulation material.

gas fired boiler 

The boiler design mainly considers the principle of boiler overhaul and stability. A water mixing device is provided at the inlet of the boiler feed water. The water supply first flushes the smoke tube bundle and then contacts the furnace liner, which increases the water temperature of the water supply to the furnace liner. Avoid the phenomenon of local cold boiling. The steam boiler reaches the maximum vaporization space, combined with the use of a reasonable and advanced steam and water separation device, the main steam quality is quite stable

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