Humidifier maintaining constant hygrometric conditions - useful in dwellings and in industrial premises, metrological stations, spray booths

摘要

A humidifier of the type incorporating a vessel in which are electrodes and which has electrically operated valves for filling it with water and emptying it, incorporates a contactor in the electrode power supply circuit, an instrument to standardise the voltage in one phase and a regulator which uses the voltage to control the water feed valve. The contactor is activated by a hygrostat. When the hygrostat detects that the humidity is too low, it causes the contactor to close and a current to pass through the water, heating it. The regulator compares the amount of electrical energy absorbed in the vessel with a prefixed amount. If the amount absorbed is below the prefixed amount, the regulator opens the water supply valve letting in water, increasing the heat exchange surface and hence the amount of water evaporated into the atmosphere. The humidifier also incorporates a programmer which empties the vessel periodically, a relay which maintains the discharge valve open if the current has been accidentally cut off, two electrodes which prevent overfilling and a reducer in the water supply line to charge at a low rate. The controller can be on-off, threshold or proportional. The system gives a constant rate of vapour formation in spite of changes in the amount of salt deposited on the electrode plates, changes in the hardness of the water, ageing of the plates and falls in voltage.