Filter device

A filter device provided in a tank for storing liquid, the filter device comprising:

• a filter case mounted on the tank and having a bottomed tubular shape with an open upper end;
• a filter element provided inside the filter case and including a first filter medium having a tubular shape;
• a lid body provided at the filter case and the filter element to cover the upper end of the filter case, and including an air vent hole configured to cause a space inside the filter element to communicate with a space outside the filter case;
• an inflow portion configured to cause the liquid to flow into an interior of the filter case and a space outside the filter element;
• an outflow portion configured to cause the space inside the filter element to communicate with the space outside the filter case;
• a back pressure valve provided at the outflow portion;
• and
• a second filter medium having a tubular shape,
• wherein
• the outflow portion includes an upper surface and a bottom surface provided separated from each other, and a first tubular portion provided protruding in an upward direction from the upper surface and mounted in a through-hole formed in the filter case,
• the upper surface includes a first hole that communicates with a hollow portion of the first tubular portion and through which the liquid flows into the outflow portion,
• an outflow port through which the liquid flows out from the outflow portion is provided in a side surface or the upper surface of the outflow portion,
• the back pressure valve includes a valve body having a plate shape, and a first elastic member provided between the bottom surface and the valve body,
• the valve body is movable between a closed position in which the valve body is in contact with the upper surface and covers the first hole, and an open position in which the valve body is not in contact with the upper surface,
• a recessed portion is provided in a surface, of the valve body, that comes into contact with the upper surface,
• in the closed position, a space formed between the recessed portion and the upper surface causes the space inside the filter element to communicate with the space outside the filter case,
• a plate-shaped member configured to cover an upper side of the second filter medium is provided on the upper side of the second filter medium,
• the bottom surface is detachably provided at the plate-shaped member,
• a second elastic member is provided between the plate-shaped member and the bottom surface,
• a mounting member is provided on a lower side of the second filter medium, and
• the second filter medium is provided in the tank via the mounting member.

A filter device provided in a tank for storing liquid, the filter device comprising:

• a filter case mounted on the tank and having a bottomed tubular shape with an open upper end;
• a filter element provided inside the filter case and including a first filter medium having a tubular shape;
• a lid body provided at the filter case and the filter element to cover the upper end of the filter case, and including an air vent hole configured to cause a space inside the filter element to communicate with a space outside the filter case;
• an inflow portion configured to cause the liquid to flow into an interior of the filter case and a space outside the filter element;
• an outflow portion configured to cause the space inside the filter element to communicate with the space outside the filter case;
• a back pressure valve provided at the outflow portion;
• and
• wherein
• the outflow portion includes an upper surface and a bottom surface provided separated from each other, and a first tubular portion provided protruding in an upward direction from the upper surface and mounted in a through-hole formed in the filter case,
• the upper surface includes a first hole that communicates with a hollow portion of the first tubular portion and through which the liquid flows into the outflow portion,
• an outflow port through which the liquid flows out from the outflow portion is provided in a side surface or the upper surface of the outflow portion,
• the back pressure valve includes a valve body having a plate shape, and a first elastic member provided between the bottom surface and the valve body,
• the valve body is movable between a closed position in which the valve body is in contact with the upper surface and covers the first hole, and an open position in which the valve body is not in contact with the upper surface,
• a recessed portion is provided in a surface, of the valve body, that comes into contact with the upper surface,
• in the closed position, a space formed between the recessed portion and the upper surface causes the space inside the filter element to communicate with the space outside the filter case,
• the outflow port is formed in the upper surface at a position overlapping with the recessed portion in a top plan view.