From water pipes to power generation boilers for biomass, Yoshimine boilers respond to requests for customization.

NHA-Type: SMALL and MIDDLE SIZED PACKAGE BOILER

• FEATURE OF PRODUCTS
• SPECIFICATION
• CONSTRUCTION

･HIGH EFFICIENCY OF 88% - 92%

Complete combustion can be achieved without heat loss by burning fuel in the spacious combustion chamber covered with full radiation water tube walls.

･WIDE COMBUSTION RANGE

Adjustable range of boiler capacity by burner control is 20 to 120%. Within this range, complete combustion and long continuous operation can be realized.

･OUTER WALL TEMPERATURE OF BOILER EQUIVALENT TO ROOM TEMPERATURE

Wholly double casing construction provides perfect heat insulation, making radiant heat of outer walls nil.

･MINIMUM NOISE

Forced draft fan is so silent that it is virtually noiseless.

･EASY CLEANING OF THE INSIDE AND OUTSIDE

Tube inside is completely cleaned by tube cleaner. Outer wall of tube bank are readily cleaned by a mechanical soot blower even during operation. All water tubes can be perfectly removed of soot at the time of performance test.

･EASY HANDLING AND ABSOLUTELY SAFE OPERATION

Simple construction makes handling easy. Safety is insured by safety devices. Double safety devices each different in type are used for burner cut-off at low water level.

･LOW RUNNING AND MAINTENANCE COST

Annual running and maintenance cost including power and boiler cleaning expenses are far lower than those required by other types.

･DURABILITY

Simple construction, easy inspection and no parts subjected to corrosion and burning guarantee exceptionally long durability.

･MINIMUM WEIGHT

Fin panel construction eliminates the needs for brick walls and makes boiler weight lighter.

･SMALL FOUNDATION AREA

Both boiler and its accessories are assembled on the minimum area with the height shorter than ever.

･MEASURES TO BE TAKEN TO REDUCE Nox EMISSION

Multiplied effect obtained by the combination of Low Nox Burner with reduced load in a combustion chamber can keep Nox emission less than regulated figures.

NHA-Type boiler has a simple construction which consists of convection zone of the vertically connected tubes to spacious upper and lower drums and a combustion chamber covered with shape bent tubes installed at the side of this zone.
Staggered arrangement of the tubes is employed at convection zone to obtain best heat absorption letting gas pass in a single passage method. The tubes at convection zone can be easily inspected by removing them temporarily for the wall separating convection zone from furnace is made of demountable fire bricks inserted between water tubes.
The tubes forming a combustion chamber side walls are bent on such a large radius that tube cleaners can easily pass through the tubes. Tubes outside cleaning can be conducted by soot blower even during boiler operation and when stopping water washing can be also conducted. In addition to these merits this type of boiler as also a suitable construction for pressurized burning for fin tubes are employed for the front, rear and side walls, around which double casing are installed to prevent gas leakage.
That the associated equipment except feed water tank and water softening equipment are all shop assembled makes boiler operation very easy.
Gas fuels such as LNG, LPG and City gas are all available for this type of boiler by selection of each suitable burner.