China's non-pressure hot water boiler, also known as atmospheric boiler, means that the top of the boiler does not withstand the hydrostatic pressure of the heating system. That is quite a "open hot water tank."
Circulating pumps can only be installed in the hot water pipe. And to install check valve and flow control valve. So circulating water pump "does not play the role of water circulation, while the role of pressurized water, the actual pressurized water pump." This is like the water supply pump in the same cold water pump.
The water reservoir to the water tower, and then by gravity to the user.
but. Japan's pressure-free boiler is not the case, it is a water-type heat exchanger installed inside the boiler, the hot water heating system does not contact with the furnace water. Circulating water pump and the role of ordinary pressure boilers, only to overcome the cycle resistance of the system without having to overcome the system of Yang Yang pressure. This is completely different from the pressureless boiler in our country. Can not vaguely say that "in recent years, 60% of Japan's hot water boilers have been replaced by pressureless boilers." So as not to be misunderstood as the promotion of pressureless boilers in Japan is Japan's kind of pressure cooker care.
No pressure hot water boiler advantages and disadvantages
1, Advantages: According to the available information summarized as follows:
(1) there is no danger of explosion, may not be supervised.
(2) Do not need to consider the problem of pressure relief in boiler room.
(3) save steel and simplify the process.
(4) scrap boiler reuse.
(5) Cancel replenishment pump.
(6) Power outage protection is good.
(7) durable surface use.
(8) Save user's investment
2, disadvantages:
(1) system cycle energy consumption problems.
(2) the problem of low static pressure of circulating pump population.
(3) circulating water pump inlet water temperature problem.
(4) Pot water and the direct contact with the atmosphere.
The main disadvantage of pressureless boilers is that circulating pumps have to bear the hydrostatic pressure of the system. Pressureless boilers consume about 2-7 times the pressure boilers. The higher the building, the greater the multiple.