An object of the present invention is to provide a chemical liquid purification method which makes it possible to obtain a chemical liquid having excellent defect inhibition performance. Another object of the present invention is to provide a chemical liquid. The chemical liquid purification method according to an embodiment of the present invention is a chemical liquid purification method including obtaining a chemical liquid by purifying a substance to be purified containing an organic solvent, in which a content of the stabilizer in the substance to be purified with respect to the total mass of the substance to be purified is equal to or greater than 0.1 mass ppm and less than 100 mass ppm.

Provided is a stopper for a liquid dispensing opening of a container which includes a main cavity, the opening having a diameter d smaller than the size of the cavity. The stopper includes a body having a central axis and being provided with a first, bottom limiter configured for preventing extraction of the stopper through the liquid dispensing opening in a first direction. The bottom limiter includes an expandable arrangement configured for assuming a first, retracted position and having a diameter D.sub.2<d allowing the bottom limiter to pass through said liquid dispensing opening and a second, expanded position having a diameter D.sub.2>d configured for preventing said extraction; the stopper also includes a second limiter configured for at least partially preventing displacement of the stopper through the liquid dispensing opening in a second direction opposite the first direction.

A filter device may include a ring filter element arranged in a filter housing in an upright manner. The ring filter element may have an upper end disc, a lower end disc, a filter material arranged therebetween, and a dirt pot provided on the lower end disc. The dirt pot may have a water separator arranged therein and provided on the lower end disc, a protruding pin, and an opening on a base side of the dirt pot. The filter device may include a functional element having a channel configured to receive the protruding pin. A portion of the functional element may be configured to penetrate the opening of the dirt pot such that the ring filter element is sealed at the opening. The portion of the functional element may have at least one water discharge opening. The filter device may be operational when the pin engages into the channel.

A filter arrangement for threadably securing to a filter head includes a housing having a surrounding wall defining an interior volume, an open mouth providing access to the interior volume and an end opposite of the open mouth. The surrounding wall has an exterior and an interior. A filter media construction is operably held within the interior volume. A sleeve, distinct from the housing, is secured to the exterior of the surrounding wall adjacent to the housing mouth and extending partially along the surrounding wall. The sleeve has an exterior and an interior. The exterior of the sleeve defines mounting threads constructed and arranged to removably mount with the filter head, when the filter arrangement is secured to the filter head. The interior of the sleeve is against the exterior of the surrounding wall. A first seal member is oriented against the sleeve to create a seal with a filter head, when the filter arrangement is secured to the filter head. A filter assembly includes a filter arrangement and a filter head. The filter arrangement is removably secured to the filter head by a threaded connection between the sleeve and the filter head. A system includes an engine utilizing a liquid and a filter assembly in fluid communication with the engine to filter the liquid. Methods of making filter arrangements include utilizing structures characterized above.

A fuel filter for a vehicle may include an upper case with a fuel inlet at a first side; a lower case provided in a structure having a fuel outlet and bonded to a second side of the upper case; and a main filter disposed in an inner space by bonding the upper case and the lower case and filtering fuel, wherein a first auxiliary filter assembly filtering the fuel toward an inner diameter of the main filter is mounted on a first surface of the main filter and a second auxiliary filter assembly filtering the fuel toward a second surface of the main filter is mounted on the second surface of the main filter.

A filter device may include a ring filter element arranged in a filter housing in an upright manner. The ring filter element may have an upper end disc, a lower end disc, a filter material arranged therebetween, and a dirt pot provided on the lower end disc. The dirt pot may be provided on the lower end disc, a protruding pin, and an opening on a base side of the dirt pot. The filter device may include a functional element having a channel configured to receive the protruding pin. A portion of the functional element may be configured to penetrate the opening of the dirt pot such that the ring filter element is sealed at the opening. The portion of the functional element may have at least one water discharge opening. The filter device may be operational when the pin engages into the channel.

A filter element comprising a filter media having a first end and a first endcap coupled to the first end of the filter media. The first endcap includes a flexible first endcap body having a first endcap rigid reinforcing member internally embedded therein. The first endcap rigid reinforcing member may comprise a wire mesh screen and the filter media may comprise a pleated filter media. The filter element may further comprise a second endcap coupled to a second end of the filter media. The second endcap may include a flexible second endcap body having a second endcap rigid reinforcing member internally embedded therein.

A removable device that ensures that the port of a filter cartridge is liquid tightly sealed to the port of the head of a housing even when there is insufficient room beneath the bowl to allow one to physically secure the cartridge port to the head port before securing the head and bowl together. The invention uses one or more removably attached alignment devices to center the cartridge in the bowl and maintain it at a height sufficient to ensure that the two ports are aligned and liquid tightly sealed to each other when the bowl and head are mated together.

A removable device that ensures that the port of a filter cartridge is liquid tightly sealed to the port of the head of a housing even when there is insufficient room beneath the bowl to allow one to physically secure the cartridge port to the head port before securing the head and bowl together. The invention uses one or more removably attached alignment devices to center the cartridge in the bowl and maintain it at a height sufficient to ensure that the two ports are aligned and liquid tightly sealed to each other when the bowl and head are mated together.

A filter device may include a ring filter element arranged in a filter housing in an upright manner. The ring filter element may have an upper end disc, a lower end disc, a filter material arranged therebetween, and a dirt pot provided on the lower end disc. The dirt pot may be provided on the lower end disc, a protruding pin, and an opening on a base side of the dirt pot. The filter device may include a functional element having a channel configured to receive the protruding pin. A portion of the functional element may be configured to penetrate the opening of the dirt pot such that the ring filter element is sealed at the opening. The portion of the functional element may have at least one water discharge opening. The filter device may be operational when the pin engages into the channel.