Sheaf-based fluid filter

A method for using a filter, the method comprising:

• introducing a fluid to be filtered into a thread-based filtration medium comprising multiple threads extending between a first end and a second end of the medium, wherein:
• the medium is at least partially housed in a tube,
• the threads of the medium are oriented lengthwise along the length of the tube with the first end of the medium oriented with a first end of the tube and the second end of the medium oriented with a second end of the tube,
• the threads at the second end of the medium are attached to a plate that provides one or more passageways for fluid, and the threads at the first end of the medium are unattached and exposed,
• the plate is coupled to a rod which provides a stabilizing axis for lengthwise motion of the plate inside the tube;
• directing the filtering fluid to flow lengthwise along the threads, from the first end of the medium to the second end of the medium, thereby:
• pushing the plate and the medium towards the second end of the tube,
• decreasing an inter-thread spacing of the medium at least in an area adjacent the second end of the medium, and
• trapping in the threads impurities present in the fluid, thereby filtering the fluid;
• removing the filtered fluid from the second end of the medium;
• introducing a washing fluid into the second end of the thread-based medium;
• directing the washing fluid to flow lengthwise along the threads from the second end of the medium to the first end of the medium, thereby:
• pushing the plate and the medium towards the first end of the tube,
• increasing the inter-thread spacing of the medium at least in an area adjacent the first end of the medium, by:
• (a) exposing at least said area of the medium from the first end of the tube, or (b) exposing at least said area of the medium from a narrow portion of the tube to a wide portion of the tube, and
• releasing the impurities trapped in the threads into the washing fluid, thereby washing the medium;
• and
• removing the washing fluid and the released impurities from the first end of the tube.