Fluid Level Gauge
A fluid level gauging mechanism external of a reservoir bottle in a dispenser which mechanism emits electromagnetic radiation and senses the electromagnetic radiation emitted which passes through the bottle or is reflected from the bottle through a wall of the bottle into the bottle at a first height and senses reflected radiation passing outwardly from the bottle at a second different height.
1 . A dispenser comprising:
a housing,
a bottle containing fluid to be dispensed,
a pump mechanism to dispense fluid from the bottle,
the bottle removably coupled to the housing for replacement,
the bottle having a wall defining a cavity therein within which fluid is contained, the wall having an exterior surface and an interior surface, the interior surface facing the cavity,
the housing carrying a fluid level gauging mechanism to estimate the level of fluid in the bottle,
the fluid level gauging mechanism comprising:
an emitter of electromagnetic radiation within a range of wavelengths, and
a sensor of electromagnetic radiation within the range of wavelengths,
the emitter carried on the housing at an emitter vertical height, and the sensor carried on the housing at a sensor vertical height different than the emitter vertical height,
the wall of the bottle including window portions permitting electromagnetic radiation within the range of wavelengths to pass through the wall, the window portions including an inlet window and an outlet window,
wherein when the bottle is coupled to the housing:
(a) the inlet window is located relative the housing at an inlet vertical height and an outlet window is located relative the housing at an outlet vertical height different than the inlet vertical height, and
(b) the emitter is located outside the bottle exterior of the exterior wall positioned to direct the electromagnetic radiation into the bottle through the inlet window, and the sensor is located outside the bottle exterior of the exterior wall to receive electromagnetic radiation from the emitter which is reflected within the bottle to pass outwardly through the outlet window,
wherein in operation the emitter directs radiation into the bottle through the inlet window and the sensor receives radiation from the emitter reflected from within the bottle out through the outlet window.
2 . A dispenser as claimed in claim 1 wherein the fluid level gauging mechanism includes a controller,
the controller controlling the operation of the emitter and sensor so as to periodically and successively perform:
(i) a step of emitting radiation with the emitter and simultaneously sensing the relative level of radiation reflected from the bottle with the sensor to determine a reflected radiation value,
(ii) comparing the reflected radiation value in one step (i) to a compared value selected from a pre-selected value and reflected radiation values sensed in another steps (i), and
(iii) identifying when a significant change in the sensed radiation values occurs, and characterizing the significant change in the sensed radiation values as an indication that the level of fluid in the bottle is below a vertical height which is a lower of the sensor vertical height and the emitter vertical height.
3 . A dispenser as claimed in claim 1 wherein the electromagnetic radiation is infrared radiation.
4 . A dispenser as claimed in claim 1 wherein the bottle wall is a plastic material translucent to the electromagnetic radiation.
5 . A dispenser as claimed in claim 1 wherein in dispensing fluid from the bottle, the bottle is not collapsed.
6 . A dispenser as claimed in claim 1 wherein the bottle is selected from a bottle which is not collapsible, a bottle having an air inlet which permits air to flow into the bottle during dispensing of fluid from the bottle so as to not substantially collapse the bottle by dispensing of fluid, and a collapsible bottle which is collapsed on dispensing of fluid.
7 . A dispenser as claimed in claim 1 wherein the wall of the bottle is made of a material which permits the electromagnetic radiation to pass therethrough, the bottle carrying labeling on its wall, the labeling configured to not prevent radiation from passing through the inlet window and the outlet window.
8 . A dispenser as claimed in claim 1 wherein the wall of the bottle is made of a material which permits the electromagnetic radiation to pass therethrough, the bottle carrying labeling on its wall, the labeling providing an inwardly directed reflective surface over portions of the wall other than the window portions which increase the reflection of the electromagnetic radiation inside the wall back into the cavity.
9 . A fluid level gauging mechanism for estimating fluid levels in a bottle and which mechanism includes a controller,
controlling operation so as to periodically and successively perform:
(i) a step of emitting radiation with an emitter and simultaneously sensing the relative level of radiation received by a sensor to determine a sensed radiation value,
(ii) comparing the sensed radiation value in one step (i) to a compared value selected from a pre-selected value and sensed values sensed in another steps (i), and
(iii) identifying when a significant change in the sensed radiation values occurs, and characterizing the significant change in the sensed radiation values as an indication of the level of fluid in the bottle is below a vertical height which is lower of the sensor vertical height and the emitter vertical height.