Abstract: This nitrogen recovery method is for causing nitrifying bacteria to decompose an ammonia component in an ammonia-containing gas, and recovering a nitrogen component contained in ammonia as an ammonia gas decomposition product, involving: supplying circulating water to a microorganism decomposition tank retaining a nitrifying bacterium carrier carrying nitrifying bacteria to maintain the carrier wet; passing ammonia-containing gas through the carrier in the wet state in an oxygen-containing atmosphere; dissolving an ammonia component in the ammonia-containing gas in the circulating water, together with an ammonia gas decomposition product produced by the nitrifying bacteria, to continue decomposing the ammonia-containing gas while the decomposition product is accumulated in the circulating water; and collecting all or a portion of the circulating water to recover the ammonia gas decomposition product, when the concentration of nitrate ion as an ammonia decomposition product in the circulating water reaches a p

Abstract: A valve device with fail-safe mechanism capable of improved production efficiency includes a valve element, a valve element housing, a third communication port provided in the valve element housing, and a fail-safe mechanism. The fail-safe mechanism includes a thermo-element and an element housing that houses the thermo-element. The element housing has a large-diameter housing, a small-diameter housing portion that accommodates the thermo-element, and a step. A valve element communicating portion communicating with the valve element housing is provided to the small-diameter housing portion. The fail-safe mechanism includes a valve plate member for closing the step and a coil spring that biases the valve plate member. A third adapter provided to the third communication port is provided with a through-hole that enables the large-diameter housing portion and the third communication port to communicate with each other.

Abstract: A valve device with fail-safe mechanism capable of improved production efficiency includes a valve element, a valve element housing, a third communication port provided in the valve element housing, and a fail-safe mechanism. The fail-safe mechanism includes a thermo-element and an element housing that houses the thermo-element. The element housing, has a large-diameter housing, a small-diameter housing portion that accommodates the thermo-element, and a step. A valve element communicating portion communicating with the valve element housing is provided to the small-diameter housing portion. The fail-safe mechanism includes a valve plate member for closing the step and a coil spring that biases the valve plate member. A third adapter provided to the third communication port is provided with a through-hole that enables the large-diameter housing portion and the third communication port to communicate with each other.