Scooba's Hydro-Pneumatic Cleaning Path

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INTRODUCTION

This document explains Scooba's hydro-pneumatic throughput. In other words the paths that air and moisture follows as that mix flows through Scooba, and with the fluid being trapped while the air continues, are described. Two 'nomenclature' sections must first be endured, then the subject matter is treated.

Nomenclature -- Robot's Features

To assist in following the below description of the forced air path through Scooba, a physical image of the various features to be discussed may prove helpful, hence two lists of feature-names follow (Note: As possible, names are taken from illustrations in the Owner's-Manual; while, other names have been 'invented' by the author.):

Viewing Scooba's bottom side, these features are listed in the order: front to rear-most:

  1. Debris Air-Jet (basically a dry process)
  2. (Debris) Vacuum Port (basically a dry process)
  3. Floor-Prep Squeegee (one long and one short -- the short-one's leading end actually precedes items (a) and (b))

These first three items are illustrated in Figure 1:

Figure 1. Scooba's "Prep-mode" Features

Wet-cleaning of the flooring is initiated and accomplished by equipment in the robot's central section, using the following elements:

Locations of these three items are labeled in Figure 2:

Figure 2. Scooba's "Washes / Scrubs-modes" Features

Viewing Figure 3, Scooba's "Tank-Well" (with Scooba's Tank removed), look for these items:

Figure 3. Features in Scooba's 'Tank-Well' -- Tank-Assembly Removed

Nomenclature -- Tank's Features

Only a few features of the Tank Assembly need be considered to support the intent of this discussion. They are:

Figure 4 identifies those features as seen from the bottom side of the Tank.

Figure 4. Scooba's "Tank" -- Viewing its Underside

Operating Methods / Modes

The Owners-Manual states that "Scooba uses four cleaning methods in every pass.", and then lists "1) Preps; 2) Washes; 3) Scrubs; and 4) Dries". If the manual is not read carefully, one may interpret that list of methods as being separate, sequential operations, but in fact, all four are in play at the same time! Certainly, the "Dries" operation cannot be successful so long as cleaning-solution is being squirted on the floor. After watching Scooba complete a cleaning job, it soon becomes obvious that Scooba has no specific floor-drying 'mode'. When Scooba either depletes its supply of cleaning solution, or a user presses its Clean-button a second time to force an early 'quit', Scooba shuts off its pump and continues to navigate around the floor as it dries some internal hardware items. The manual advises: "...Scooba will enter a brief internal drying mode...removes any water that may have accumulated in the cleaning head...". Note: The "cleaning head" is composed of the Main Brush plus its enclosure, and with the integral Vacuum Squeegee.

Figure 5. Scooba's "Cleaning Head" Features -- (seen from above)

As that internal drying occurs, there will be some floor-drying accomplished, because the surplus air, in appreciable volume, which the Blower exhausts down onto the floor, is bound to assist local evaporation. Similarly, the Brush continues spinning around, further disturbing the moisture film to make it possible for the general cross-flow of air to either aid evaporation or send droplets towards the Dirty Tank. The relatively short length of time that Scooba spends in this mode will, in general, disallow total floor-area drying.

Hydro-Dynamic Paths Through Scooba

Having dispatched all of that introductory material, the subject of this document can now be engaged:

  1. There are two suction inlets against the floor, one is the Debris Vacuum Port sucker at the vertex of the long and short Floor-Prep Squeegees, and the second is the full-width, two-lip Squeegee Vacuum, which trails the Main Brush. All incoming air must take those two inlet paths.
  2. Materials collected by inlets in (1) are ducted straightaway to the Dirty-Tank ("DT", hereafter), where some debris will fall out of the air-stream and become trapped in the increasing volume of collected dirty-solution.
  3. Air-flow moves through the DT and heads back down to the robot via a large duct located at Scooba's LHS. On the way, the metal filter-screen, ("Filter") is encountered, thus trapping particles that did not stay put in the DT.
  4. The moving air finally reaches the Blower -- the item which the air has been seeking ever since it left the floor!
  5. Following the boost provided by the Blower's action, the air-stream runs into an unequally branched duct at the Blower's outlet. The larger of the two ducts exhausts the bulk of the air back onto the floor, while the smaller duct terminates at the pressure jet (Debris Air-Jet) seen at the left end, the wide- spread ends, of those vee-arranged Floor-Prep Squeegees (mentioned in (1)).

Figure 6. Air Path Out of the Tank and Into the Robot

That description may be all one needs. It is quite a simple pathway, but there may be some baffling baffle trickery inside the DT, that turns a simple-concept into a complex-design.

Enhanced understanding may be obtained by reading a file that describes features of the Tank Assembly, refer to: Tank's Details.

Reading that material may fill in some gaps, but we will never know exactly what is in that Tank-Assembly until we saw one open!.

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