Wet pick-up vacuum unit

In a fan section for a wet pick-up type vacuum cleaner unit comprised of a motor section and a fan section, said motor section containing a motor and means for causing motor-cooling air to be drawn into said motor section through an entrance thereto and discharged through an exit therefrom,

• said fan section having a fan chamber provided with an inlet port and containing a fan system which draws working air (by which cleaning and pick-up is performed) into said chamber through said inlet port and discharges the same through an outlet remote from an entrance or exit for the motor-cooling air of said motor section,
• said fan chamber having a wall provided with support means for a main bearing in which is journaled a shaft extending into said fan chamber and on which said fan system is mounted so as to provide a space between said bearing and the most closely adjacent fan of said fan system,
• said fan section having a sealing air inlet which is spaced from either a working air inlet or outlet of said fan section or a motor-cooling air entrance or exit of said motor section and which sealing air inlet leads through a sealing air passageway toward the location where said shaft extends from said bearing into said fan chamber, said passageway including a baffle portion segregating the passageway from the balance of said fan chamber and having an opening through which said shaft extends into said chamber, said opening being larger than the portion of said shaft passing therethrough to provide a substantially annular orifice through which sealing air, under normal operating conditions, may be drawn from said passageway into said fan chamber whereby liquid carried by said working air into said fan chamber and which might otherwise accumulate adjacent said bearing in the space between said bearing and the most adjacent fan is swept, by the sealing air passing through said orifice into said fan chamber, back into said fan chamber for discharge therefrom with said working air,
• the improvement comprising:
• check valve means preventing reverse flow of air and liquid carried thereby through said orifice, passageway, and sealing air inlet under an abnormal condition in which, but for said check valve means, resistance to discharge of said working air from said fan section outlet would exceed the resistance of reverse flow through said orifice and passageway and out of said sealing air inlet.