Discharge valve unit and fluid device

A discharge valve unit configured to be attached to a fluid device, the fluid device including a housing including an inlet and a first reservoir for liquid that has flowed from the inlet, the fluid device including a first valve mechanism including a first discharge hole for liquid provided in the first reservoir and a float accommodated in the first reservoir and configured to open and close the first discharge hole, the discharge valve unit comprising:

• a valve case configured to be detachably attached to the housing, the valve case including a second reservoir for liquid configured to communicate with the first reservoir not through the first discharge hole but through a communication hole when the valve case is attached to the housing;
• and
• a second valve mechanism disposed in the second reservoir, the second valve mechanism including a second discharge hole for liquid having an opening diameter larger than an opening diameter of the first discharge hole, and including a valve member accommodated in the second reservoir and configured to open and close the second discharge hole, wherein
• the second valve mechanism includes a spring configured to bias the valve member in a valve opening direction, and when a pressure of the second reservoir increases to a predetermined value, the valve member closes the second discharge hole under the pressure against a biasing force of the spring.