Liquid level indicator

• US 4,213,338 A
• Filed: 02/21/1979
• Issued: 07/22/1980
• Est. Priority Date: 02/21/1979
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Hardy, Albert L.
• Primary Examiner(s): Goldberg, Gerald
• Assistant Examiner(s): Corr, Denis E.
• Application Number:
  US06/013,335
• Time in Patent Office: 517 Days
• Field of Search: 73/299, 73/323, 73/747, 73/302, 116/227, 134/113, 222/23
• US Class Current: 73/299
• CPC Class Codes: A47L 15/4418 in the form of liquids A47L15/4409, A47L15/4436, A47L15/4445 take precedence
• CPC Class Codes: G01F 23/162 by a liquid column

Abstract

An indicator providing a visual indication of the level within a rinse aid dispenser tank for dishwashers, consisting of a U-tube containing an indicator liquid having one leg in communication with the lowermost region of the tank and with the other disposed adjacent a viewing window. Air pressure generated in the connecting tubing by the relative liquid level in the tank acts to control the position of the liquid in the U-tube to provide a level indication at the viewing window. The air column intermediate the tank and the U-tube section is vented each time the door is opened to avoid variations in indication occurring with temperature and atmospheric pressure changes. The indicator liquid is introduced through a fill and drain tube extending from the upper end of the leg into the dispenser tank, such that a calibrated volume of liquid is introduced by flow into the U-tube from the tank and drain back of the excess over the calibrated volume. An anti-siphon tube in communication with the fill and drain tube precludes siphoning of the rinse aid liquid back into the tank as the excess liquid drains back through the fill and drain tube upon closing of the dishwasher door.

Claims

1. A liquid level indicator for a tank, said tank being movably mounted to be alternately positioned in a first or second position, said second position vertically tilted from said first position, said indicator arrangement comprising:

an air column fluid passage in fluid communication with the lower region of the interior of said tank, with said tank in said first position, said air column fluid passage including a first portion extending generally horizontally away from said tank, and the portion thereof immediately adjacent said tank elevated with respect to said tank with said tank in said second position;

said air column fluid passage including a second portion extending upwardly from said tank and said first portion of said air column fluid passage with said tank in said first position;

a vertically reversely curved fluid passage section in fluid communication with said air column at a location remote from said tank with said reversely curved sections forming a U-tube disposed in a vertical position with said tank in said first position;

means for venting the upper end of the U-tube leg remote from said air column fluid passage;

means for venting said tank to the atmosphere;

viewing gage means associated with said remote leg of said U-tube;

a volume of indicator liquid retained in said U-tube;

whereby said remote leg acts as an indicator leg indicating the level of liquid in said tank by movement of said liquid into said first portion of said air column fluid passage by positioning of said tank in said first position, and the resulting compression of air in said air column fluid passage indicating liquid in said U-tube enabling liquid level indication by the position of indicating liquid in said indicator leg and in viewing of said liquid level by the aid of said viewing gage means.

2. The indicator arrangement according to claim 1 wherein said air column fluid passage enters into fluid communication with said tank at an upper point thereon of said tank in said second position to insure drainback of said liquid disposed in said air column fluid passage back into said tank upon movement of said tank from said first to said second position.

3. The indicator arrangement according to claim 1 further including a fill and drain fluid passage in fluid communication with an upper end of said remote leg of said U-tube, said fill and drain fluid passage being elevated above said remote leg of said U-tube with said tank in said second position, whereby liquid may be introduced into said U-tube to provide said volume of indicator liquid by filling of said tank with said tank in said second position, and further including an anti-siphon fluid passage in fluid communication with said fill and drain fluid passage and said remote leg of said U-tube, said anti-siphon fluid passage further in fluid communication with said tank in the upper region thereof above the liquid level in said tank, thereby precluding siphoning of said volume of indicator liquid when said tank is moved to said first position.

4. The indicator arrangement according to claim 3 wherein said anti-siphon fluid passage is connected to said tank through a side surface, with said tank in said first position, at a point above the level of liquid in said tank corresponding to the tank level with said tank in said second position and said U-tube just filled.

5. In a liquid level indicating arrangement of the type including a tank with the liquid level therein visually indicated, an air column fluid passage extending from said lower region of said tank interior and means for providing a visual indication of the level of liquid in said tank by the pressure developed in said air column fluid passage by liquid displaced from said tank and compressing an air column in said air column fluid passage, in combination:

means mounting said tank for movement between a first position and a second position, said liquid level in said tank being indicated by said indication means when said tank is in said first position;

means for venting an air space in said tank;

means for causing said liquid introduced into said air column fluid passage upon positioning said tank into said first position to drain back into a vented air space in said tank upon positioning said tank into said second position, whereby said air column fluid passage is vented thereby correcting for the effects of temperature and barometric pressure conditions upon each movement of said tank from said first to said second position.

6. In a liquid level indicating arrangement of the type including means for visually indicating the level in a tank movably mounted to be positioned in either a first or second position, said second position vertically tilted from said first position;

an air column fluid passage in communication with a lower region of the interior of said tank;

a U-tube in fluid communication with said air column fluid passage;

a volume of indicator liquid in said U-tube assuming differing levels in the respective legs of said U-tube section by pressure exerted by liquid in said tank acting through said air column fluid passage;

viewing gage means associated with the second leg of said U-tube remote from said air column fluid passage;

the improvement comprising;

means for introducing said indicator liquid from said tank, said means including a fill and drain fluid passage extending from said tank into said second leg of said U-tube;

an anti-siphon fluid passage in fluid communication with said fill and drain fluid passage and said second leg of said U-tube, said anti-siphon fluid passage also extending into said tank;

whereby indicating liquid may be introduced into said U-tube by movement of liquid in said tank through said fill and drain fluid passage into said U-tube by positioning of said tank in said second position vertically tilted from said first position, whereby said level in said tank is to be indicated, without siphoning said liquid in said U-tube back into said fill and drain fluid passage upon movement of said tank back to said first position.

7. A rinse aid tank indicator arrangement for a front-loading dishwasher of the type wherein a rinse aid tank is mounted in an access door of said dishwasher, said access door being mounted for opening movement from a first, generally vertical, closed position to a second, generally horizontal, open position, wherein said dispenser tank has a fill opening accessible with said access door in the open position, in combination:

a liquid level indicator arrangement including an air column fluid passage extending from said rinse aid tank into fluid communication with a vertically reversely curved section forming, with said door closed, a vertically disposed transparent U-tube having a first leg in communication with said air column fluid passage and a second indicator leg remote from said air column fluid passage;

a quantity of indicator liquid in said U-tube;

viewing gage means associated with said indicator leg providing an indication of said indicator liquid level therein, whereby compression of the air in said air column fluid passage by liquid in said rinse aid tank causes said indicator liquid in said U-tube indicator leg to assume positions in correspondence thereto, whereby visual indication of said liquid level and said rinse aid detector is provided in said front access door;

the terminal portion of said U-tube leg remote from said air column fluid passage extending vertically upward therefrom with said door in said open position, whereby indicator liquid introduced into said U-tube will be retained therein during opening and closing of said door.

8. The rinse aid tank indicator arrangement according to claim 7 further including means for venting said air column on each opening movement of said access door, said means including a portion of said air column fluid passage disposed extending generally horizontally from said tank, with said door in said closed position, said horizontally extending portion of said air column fluid passage including a portion inclined vertically upward from the tank with said door in said open position and extending for a distance sufficient to accommodate the entire volume of liquid displaced from said rinse aid tank with said rinse aid in said tank at a maximum level condition with said door in said closed position, whereby all of said displaced liquid in said air column fluid passage will drain back into said rinse aid tank upon movement of said door to said open position to thereby vent said air column fluid passage.

9. The rinse aid tank indicator arrangement according to claim 7 further including a fill and drain fluid passage in communication with said terminal portion of said indicator leg of said U-tube, an anti-siphon fluid passage in communication with the point whereat said fill and drain fluid passage is placed in communication with said terminal portion of said indicator leg of said U-tube, thereby allowing indicator liquid to be introduced into said U-tube from said tank by flow therein through said fill and drain fluid passage and the excess drained back into said tank upon said movement of said access door to said closed position, said anti-siphon fluid passage precluding the siphoning of indicator liquid out of said U-tube.