Height-adjustable tank valve

A valve for maintaining in a tank an intended volume of water by admitting water to the tank when there is a lesser volume therein, said valve comprising:

• a telescopic-style riser comprising:
• an outer tube with an upper end and a lower end, said lower end being adapted to be attached to said tank, said outer tube having an axis, an internal passage with an axially-extending interior cylindrical wall with an inside diameter, and a tongue projecting into said internal passage;
• an axially extending guide fixed on the outer wall of the outer tube, having an aligning passage therein;
• an inner tube having an upper end, a lower end, and an outer wall with an outside diameter, said outside diameter being smaller than said inside diameter, whereby said inside tube is axially reciprocally slidable in said outer tube;
• a bridge segment on said inner tube extending laterally relatively to said axis;
• a tube mount on said bridge, said tube mount having a mounting opening;
• a tank fill tube fixed in said tube mount, and slidably fitted in the aligning passage in said guide, said tank fill tube being open for flow of water into said tank, and stiffly flexible, tending to remain straight and axial when the mounting opening and the guide are axially aligned, but being sufficiently flexible to bend to permit limited rotation between the inner tube and the outer tube;
• a groove pattern extending for a substantial axial length in the outer wall of the inner tube, said pattern including alternate bar segments and pass segments, said bar segments lying in respective planes normal to said axis, and said pass segments being substantially parallel to said axis, said bar segments being parallel to and spaced from one another, and said pass segments being parallel to one another but alternately spaced from successive ends of said bar segments, whereby to form a serpentine groove with pass segments alternately disposed at ends of said bar segments, said tongue being inserted into said groove whereby when it is in a pass segment it enables axial movement and prevents rotational movement between said inner tube and outer tube, and when in a bar segment it prevents axial movement and enables rotational movement between them, said tank fill tube, tube mount, and guide being substantially aligned when the tongue is in a bar segment;
• and.
• valve workings carried by said inner tube to control flow of water through said riser and tank fill tube.