To enable long-term continuous use of a drain trap, by lengthening a service life of a control valve offered to drainage from a drain tank.
This drain trap includes the drain tank 1 having an introducing port 1a and a drain port 1b of the drainage, a motor-operated valve 2 arranged in the drain port 1b, a water level sensor 3 for detecting a water level in the drain tank 1, and a control device for controlling the motor-operated valve 2 based on a detecting result of the water level sensor 3, increasing opening of the motor-operated valve 2 little by little whenever a specific time passes when the water level in the drain tank 1 exceeds an upper limit value H1 and reducing the opening of the motor-operated valve 2 in a predetermined width about the specific time when the water level in the drain tank 1 becomes less than a lower limit value L1.
SAKAGUCHI OSAMU
| JPH08200593A | 1996-08-06 | |||
| JP2005061531A | 2005-03-10 | |||
| JPS59133785U | 1984-09-07 |
Masatake Shiga
Kazuya Nishi
Hisanori Takahashi
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