GB2141523A - Outlet float seal for tank of electric vacuum cleaner - Google Patents

Abstract

An electric vacuum cleaner 10 includes a tank 12 for collecting material suctioned into the vacuum cleaner and includes a suction motor for suctioning air from the tank. The outlet 50 from the tank 12 to the suction motor is surrounded by a flexible bellows sleeve with a bottom edge 102. A filter cage 62, 64, 68 for supporting a cannister filter 70 encloses the tank outlet 50 and the sleeve. A shaft 90 is upstanding from the floor 68 of the cage. An inverted cup-shaped sealing float 80 is guided for movement on the filter cage shaft 90 up toward the tank outlet 50, 102 as liquid fills the tank 12. The top 82 of the float 80 is spherically rounded to seat against and seal the outlet 50 past the sleeve bottom edge 102. The bottom portion 84 of the float 80 flares conically wider. <IMAGE>

Description

SPECIFICATION Outlet float seal for tank of electric vacuum cleaner BACKGROUND OF THE INVENTION The present invention relates to electric vacuum cleaners capable of suctioning both dry particulate materials and liquids, and particu larly relates to a float seal at the outlet from the collecting tank of the vaccum cleaner for halting suction when the tank has filled with collected liquid. The float seal is useful for any suction device besides a vacuum cleaner.

An electric vacuum cleaner broadly includes suction means for generating suction force, a suction inlet through which material is to be suctioned and a collecting means, or tanks disposed between the suction inlet and the suction means. Without limitation to one type of vacuum cleaner, the present invention is shown in a tank or cannister type electric vacuum cleaner, where the collecting means is a large tank or drum, the suction inlet to the tank is through a port in a wall or the lid of the tank and the suction means is supported at the lid of the tank and communicates into the tank for suctioning air out of the tank, thereby for generating suction force at the suction inlet. A hose with an intake nozzle remote from the suction inlet port is received in that port.The suction means is a blower motor having its inlet communicating into the tank or generating a vacuum in the tank and having its outlet communicating externally of the tank and of the motor. The blower motor may be a bypass type motor, which has a separate cooling air circuit for cooling the motor. The entire cooling air circuit is external of the tank and is not pertinent here.

Filter means are disposed before the outlet from the tank to the blower motor to retain collected particulate materials in the tank while permitting exit of air that has been pulled through the tank.

It is desirable to halt intake though the suction inlet when the tank becomes filled.

This is a safety measure. When the tank becomes filled with particulate materials, which cannot pass the filter and which thus block the filter, the passage of air to the blower motor will be inhibited and suction will be halted. The invention is not directed to solving a problem experienced with dry material pickup.

Where the vacuum cleaner also is intended for suctioning liquid into the tank, because the liquid can permeate through the filter when the tank is eventually filled with collected liquid up to the filter, the liquid will pass the filter and will be suctioned through the tank outlet and through the suction motor, undesirably expelling the collected liquid and possibly damaging the motor. Therefore, means are required to shut off suction by the blower motor when the tank becomes filled with liquid. To this end, it is conventional to dispose a float seal under the outlet from the tank, and it floats up on collected liquid in the tank to eventually block the tank outlet.

For containing the float seal, it is also conventional to provide a filter supporting cage extending down into the tank and surrounding the outlet from the tank. A replaceable filter is installed on and supported by the cage.

Inside the filter cage is a floatable element which normally rests on the bottom of the cage, spaced away from the outlet from the tank. The element is adapted to float on liquid, and when liquid fills the tank up to the filter cage and then permeates through the filter into the cage, the floatable element is floated up toward the tank outlet. As the element approaches the outlet, the suction force at the outlet eventually draws the element which has floated up to it securely against the outlet to thereafter block further air flow through the tank outlet.

The filter cage serves as a guide for the floatable element to keep it beneath the tank air outlet and guides it to float up to that outlet. The filter cage and the floatable shutoff element in the cage are both shaped and positioned so that the element is spaced far enough away from the tak outlet that the element must travel a considerable distance to shut off flow at the tank outlet. This assures that the element does not prematurely pop up and close off the outlet.

The outlet from the tank comprises an opening surrounded by a peripheral edge which defines a seat for sealing with the floatable element. Typically, the outlet opening may be surrounded by a sleeve which projects into the tank, and the edge of the outlet is thus at the free end of the sleeve.

The distance which the sleeve projects into the tank is selected so that when the floatable element finally seats against the free edge of the outlet sleeve, the tank has the desired level of fill of liquid. In a typical electric vacuum cleaner, the floatable element is a ball which is designed to float on the liquid in the tank as it rises in the filter cage until the ball floats up to the suction outlet from the tank.

The ball is not restrained in the filter cage and can bounce around or shift freely. When the vacuum cleaner is being used, sudden movement or tipping of the tank would cause an unrestrained ball to move about or tumble, and may throw the ball up to the suction outlet, where the ball will be sucked into the outlet, prematurely shutting off suction until the vacuum cleaner is shut off and restarted.

Also, it is possible for the ball to get lodged or trapped outof alignment with its seat at the edge of the tank outlet.

Furthermore, most ball floats are either molded in two separate pieces which are thereafter secured together or they are molded as one piece in a two part mold. In either case the resulting ball has a seam. If the seam is rough, projecting or otherwise less than perfect, a good seal would not be obtained between the ball and the entrance to the tank outlet unless an additional gasket or soft seat is provided at the edge of the tank outlet.

Examples of electric vacuum cleaners with floatable ball valves are numerous, one being U.S. Patent 4,185,974.

Some of the above-described problems associated with ball floats which are supported inside a filter cage would not similarly occur with a float seal for an electric vacuum cleaner which is guided on a support shaft, as in U.S.

Patents 4,055,405; 3,343,199; 2,989,769; and 3,290,865. Also of interest is U.S. Patent 4,246,011. All of the float seals illustrated there are closed geometric shapes not supported in or guided by a filter cage.

Furthermore, the most effective floatation of a float seal is obtained where maximum displacement of liquid is possible for a minimal weight floatable element. The illustrated floatable elements of the prior art, generally being completely closed bodies or solid bodies, displace an amount of liquid which is smaller than a desired maximum.

SUMMARY OF THE INVENTION The invention is directed to A float seal for the air outlet from the tank of an electric vacuum cleaner, or the like, wherein the electric vacuum cleaner includes: a tank for collecting suctioned materials, including liquid; an inlet to the tank for suctioned materials; a suction motor connected to the tank for applying suction pressure to the tank, and an outlet from the tank communicating with the suction motor; the float seal comprising: the tank outlet comprising an opening communicating out of the tank and the opening being defined by a peripheral edge of the opening within the tank; a float, for floating up on liquid collected in the tank to the edge of the outlet opening; the float being cup-shaped, including a top end which projects up to the edge of the outlet, and the top end being wide enough to seat against the edge of the outlet, the top end being convexly rounded for being received in the opening and for seating against the edge of the outlet opening; the float including a bottom end, spaced away from the top end, and the bottom end being open; the cupshaped float having an open interior in open communication with the bottom end of the float; a float guide supported in the tank for defining a fixed pathway along which the float can float to the edge of the outlet opening, and the guide being directed to direct the top end of the float against the edge of the outlet opening for effecting a seal between the float and the edge of the outlet opening.

According to the present invention, the float for the float seal is supported on a float guide which disposes the float beneath the tank outlet, and the float floats up along the guide toward the tank outlet, whereby the float will not misalign with the tank outlet.

The float is generally cup-shaped, and is an inverted cup. The top portion of the float projects up toward the tank outlet, is smooth and convexly rounded, and preferably spherically rounded, for being received in the open end of the outlet and for sealing against the edge of the seat which defines the tank outlet.

The top portion of the float is a sufficient section of the sphere that its rounded part will seat against the edge of the seat of to the tank outlet.

Beneath its round top portion, the float extends downwardly to its open bottom end, and the interior of the float is open. Beneath its rounded top portion, the cup-shaped float element flares generally conically wider, which stabilizes the float throughout its entire movement. Also, the widened float displaces a relatively greater amount of water than a nonflaring float would, which helps the open bottom float to float more easily. The top of the float is closed off so that air inside the float will be trapped there as liquid rises and this will aid the float in displacing water and rising.

The float guide for the float comprises a guiding element supported in the tank and particularly projecting up from the floor of the filter cage toward the tank outlet. The float is provided in its interior with a cooperating guide which slides along the guiding element on the floor of the filter cage as the float moves. For example, the guiding element in the filter cage is a shaft extending up from the floor of the filter cage and inside the float while the cooperating guide on the float is a sleeve bushing which extends around the shaft to be guided by the shaft and to thereby guide the float.

Other objects and features of the present invention will become apparent from the following description of a preferred embodiment of the invention considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side elevational view, partially in cross-section, of an electric vacuum cleaner in the vicinity of the outlet from the tank, and showing the float of the invention in a first condition; and Figure 2 is a framentary view of the float shown in Fig. 1, with the float shown in a second condition.

DESCRIPTION OF A PREFERRED EMBODI MENT The present invention is now described in conjunction with a cannister or tank type electric vacuum cleaner which is used for collecting various types of material, dry and wet particulate materials and liquids. The outlet from the collecting tank is through a filter, and the filter is supported on a filter cage. An example of one such electric vacuum cleaner with a ball-type float seal for the tank outlet is shown in U.S. Patent 4,185,974, although the basic construction of a cannister or tank type vacuum cleaner is quite well known to persons skilled in the art, without examples being needed.

The cannister type electric vacuum cleaner 10 includes a conventional cylindrical metal tank 12 which is closed at its bottom (not shown). The upper peripheral edge 14 of the tank is folded over to form an annular engageable bead or rib. An inlet fitting or port 16 to the tank is illustrated as being disposed in the side wall of the tank. The invention may be used with any cannister type vacuum cleaner, including one where the inlet to the tank is through the lid. The inlet fitting 16 receives a hose, or the like, not shown, to which an intake nozzle is connected. Materials to be collected in the tank are suctioned through the hose, pass through the inlet fitting 16 and fall into the tank.

Seated at the top of the tank 12 and secured at the upper peripheral edge 14 thereof is the lid and filter cage assembly 20, which may be of any conventional design, or may be of the design shown in aforesaid patent 4,185,974. The lid of the assembly 20 comprises a solid circular disc 22 with an outer diameter slightly greater than the external diameter of the tank 12. The lid 22 is emplaced over the upper edge 14 of the tank.

The upper edge 14 is bracketed by the annular internal sealing flange 24 and the annular external sealing flange 26, and the placement of these flanges is selected to cooperate with the tank edge 14 to securely squeeze tightly over the edge 14. Clamping buckles, or the like (not shown), removably hold the lid securely to the tank.

The lid has circular opening 32 defined in it. Radially immediately outward of that opening is the narrow supporting shelf 34. The lid includes motor support 40 which is a disc having a diameter slightly greater than that of the opening 32. The support 40 rests on the annular shelf 34 and is held in position there by the upstanding annular flange 42 on the lid. The support 40 carries the conventional electric vacuum cleaner blower motor 44 on it.

The blower motor 44 is a conventional blower motor and is thus not shown or described in detail. It has an inlet which faces down to communicate with the outlet 50 from the tank and has an outlet from the motor housing above the lid. A fan in the motor draws air through the tank inlet 16 and blows air out the motor outlet. This conventional blower motor is known to one skilled in the art and thus is not shown in detail.

The annular gasket 46 between the motor 44 and the support 40 damps vibration and seals the motor inlet. The upstanding annular flange 48 on the support 40 positions the gasket 46 and the housing of the motor 44.

There is an opening 50 through the support 40. Through the opening 50, the inlet to the motor 44 communnicates through the lid and into the tank 12. The opening 50 is the outlet from the tank. The gasket 46 seals the motor inlet so that inlet to the blower motor 44, therefore, is from the tank outlet. There is an annular sleeve 52 disposed on the underside of the support 40 which defines the opening 50 and which serves as a support for the bellows 100 described below. The bottom edge 53 of the sleeve 52 and the sleeve itself are circular and the bottom edge defines the seat for the below-described float.

The vacuum cleaner is intended to draw in particulate materials along with the air that is suctioned through the inlet fitting 16. Such particulate materials are to be collected in the tank 12 and must not be permitted to exit through the exit opening 50. To this end, filter means 60 is provided. The means 60 defines an enclosure for the float 80. Beneath the lid 22 at the opening 32, there is an annular depending flange 62 which may be integrated with the lid 22, whereby the illustrated lid 22 and the below-described filter cage 62-68 are an integral construction. Of course, a conventional filter cage, which is separate from the lid to which it is affixed may be used with this invention.

Supported beneath the annular flange 62 are a circumferential array of vanes 64, which are widely spaced apart as at 66 to define a filter supporting cage with clear passageways between the vanes 64 for air to leave the tank 12. At the bottom of the vanes 64 is the closed off floor 68. The elements 62-68 together define the filter cage.

An annular drum-type or cannister filter unit 70 is slipped over the filter cage, is supported internally by the exteriors of the vanes 64, seals with the flange 62 above and rests on the periphery 69 of the floor 68 below, closing off the open areas of the filter cage and providing a filter between the interior of the tank and the outlet opening 50 through the lid. While the filter 70 is capable of trapping particulate materials, it cannot block the passage of liquid through itself, whereby as the level of liquid in the tank 12 rises above the floor 68 of the filter cage, the level of liquid in the filter cage rises as well, and this lifts the float 80.

The filter cage has a number of characteristics which were selected because of the intended purpose of this type of vacuum cleaner, which is to collect either liquid or particulate materials. Dry materials would simply fill the tank, and the precise configuration of the filter or the support for the filter would not be that important. It is because the tank collects liquid that the filter cage and the filter it supports are configured as illustrated. As liquid collects in the tank, the level of liquid rises. The filter cage projects down from the lid into the tank. When the tank becomes filled with liquid, and were the level of liquid to rise to, or quite near to, the outlet opening 50 in the lid, liquid which permeates through the filter and into the cage might be suctioned out of the tank through the motor, which is undesirable.Therefore, the exit of liquid should be stopped before it reaches to the outlet opening 50.

For preventing the passage of liquid through the tank outlet opening 50, the float 80 is disposed beneath the tank outlet. When the liquid rises sufficiently in the tank and in the filter cage, it floats the float up toward the tank outlet. Eventually, the float floats near enough to the tank outlet that the air flow through the outlet sucks the float into the outlet and against the edge 53 of the outlet closing off the outlet against further flow of air and liquid. Therefore, the vanes 64 of the filter cage are sufficiently elongate to keep the float spaced away from the edge 53 of the tank outlet sleeve 52, until the float has floated up into the vicinity of the tank outlet by liquid rising in the tank 12.

The float 80 for sealing off the tank outlet 50 comprises a hollow, inverted cup-shaped body having a convexly rounded, frusto-spher icily shaped, top portion 82 with a spherical radius greater than the radius of the sleeve 52 at its bottom edge 53 and the spherically curved top portion of the float 80 extends far enough down the body of the float that when the float 80 rises to its outlet sealing position shown in Fig. 2, the surface of the rounded top portion 82 seats against the bottom edge 53 of the sleeve 52 and makes a good seal with the tank outlet. Because the top portion 82 is frusto-spherically rounded, an excellent seal is provided even if the seat defined by the sleeve edge 53 and the spherical top portion 82 of the float are not perfectly round or are not precisely aligned.

Depending beneath the spherically curved top portion 82 of the float 80 is a frustoconically downwardly flaring body portion of the float, which terminates at the bottom circular rim 86 of the float. The entire bottom end of the float 80 is open, whereby when the float 80 rises from its position of Fig. 1 to its position of Fig. 2, there is nothing closing off the bottom of the float 80. In the bottom, unfloated position of the float shown in Fig.

1, the bottom rim 86 of the float rests on the floor 68 of the filter cage.

Projecting downwardly from the interior of the top portion 82 of the float 80 is the tubular guide bushing 88. A cooperating shaft 90 is affixed to and projects up from the floor 68 of the filter cage and extends into the interior of the bushing 88. As shown in a comparison of Figs. 1 and 2, the float 80 is guided for upward and downward movement on the shaft 90 through cooperation between the bushing 88 and the shaft 90. The shaft 90 is of a height that it guides the entire rise of the float 80, yet it is short enough that it does not project through the top of the float 80 when the float is down. The entire interior 92 of the float is open, except for the depending bushing 88.

The exterior of the float 84, and particularly its top portion 82, is smooth and seamless to ensure a good seal with the entrance edge 53 to the outlet sleeve 52. The shape of the float is in part selected that it might be molded in a single mold cavity, whereby no seam is produced on the top portion 82, which has the curved surface that seats against the outlet edge 53. The float is simple and light in weight. As collected water rises in the tank 12 and rises above the level of the floor 68 of the filter cage, the trapped air in the open interior 92 of the float 80 helps give the float buoyancy and causes it to rise. The greater, flaring width of the bottom portion 84 of the float cooperates in displacing a greater amount of water than would a straight walled or even a spherical float, aiding in the rising of the float.

For assuring that the shut-off of suction will always occur when the tank is filled with liquid, the float is preferably comprised of material which is sufficiently floatable that even were the air pocket absent from the interior 92, the float would still rise to seal the tank outlet 50.

The outlet sleeve 52 is extended downwardly by the flexible bellows 100 which is an optional element which repositions the entrance to the tank outlet, dependent upon the suction force then present in the tank. The illustrated bellows is the subject of co-pending U.S. Application 489,369, filed April 28, 1983. The float of the present invention will perform comparably and will have the same features and benefits, regardless of whether a bellows 100 is present. The structure and operation of the bellows, in cooperation with the float 80 of the invention, is now described.

The vacuum cleaner may be used either to suction a mixture of liquid and air or to suction liquid alone. The float 80 will first seat against the bottom edge 53 of the sleeve 52 at different liquid fill levels of the tank, dependent upon whether the vacuum cleaner is then suctioning mixed liquid and air or liquid alone. When the vacuum cleaner is suctioning mixed liquid and air through the inlet hose to the fitting 16, the amount of air flow through the outlet 50 and thus through the sleeve 52 is relatively greater and more rapid. On the other hand, when the nozzle of the inlet hose to the fitting 16 is submerged in a pool of liquid, and no air is being suctioned along with the liquid, the amount of the air flow through the sleeve 52 and the tank outlet 50 is considerably less and slower.

As the float 80 floats up near the bottom edge 53 of the sleeve 52, the air flowing past it will suck the float 80 up to the bottom edge 53 of the sleeve and the velocity and amount of the air flow will determine how close the float 80 must be to the bottom edge 53 of the sleeve 52 before the float is sucked up to it. Because of the different air flow rates when mixed air and liquid is being suctioned or liquid alone is being suctioned, the float 80 will be pulled off the rising liquid, and seat against the bottom edge 53 of the sleeve 5-2 at an earlier point, that is when the tank is less filled, when mixed liquid and air are being suctioned than when liquid alone is being suctioned.The bellows 100 is designed to avoid this differential, so that the float 80 will seal of the outlet from the tank at the same level of fill of the tank, whether the vacuum cleaner is suctioning liquid alone or mixed liquid and air at the time that the float is being floated up near the outlet from the tank.

The bellows 100 is a flexible, accordionlike, open ended, compressible and expansible hollow bellows. The bellows has a normal natural bias toward its expanded condition of Fig. 1. With the bellows 100, the entrance to the air outlet from the tank 72 is not fixed at the bottom edge 53 of the sleeve 52. Instead, that entrance is at the bottom edge 102 of the annular sleeve 104 beneath the bellows 100. The sleeve 104 is resiliently stretchable so that it expands around the top end 82 of the float and forms a sealing gasket as the float rises into the sleeve 104. The bottom edge 102 of the sleeve 104 thereby serves as the entrance port for the air outlet from the tank.The height of that edge 102 above the floor 68 of the filter cage is automatically variable dependent upon the velocity of the air passing through the sleeve 104 and the tank exit 50, which velocity, in turn, is dependent upon whether the vacuum cleaner is suctioning mixed liquid and air or liquid alone. The upper end of the bellows 100 is fixed to a collar 106 which is secured to the exterior of the sleeve 52, and the collar 106 is spaced slightly up from the bottom edge 53 of the sleeve 52. The bellows 100 is sufficiently flexible that it corresponds to the variations in the rate and volume of air flow passing through the sleeve 104, bellows 100 and sleeve 52, dependent upon whether the vacuum cleaner is suctioning air or liquid in air, on the one hand, or liquid only, on the other hand.When the vacuum cleaner is suctioning liquid only, as when the inlet nozzle (not shown) to the tank inlet 16 is submerged in a pool of liquid, and there is, as a result, a reduced amount of air flow and velocity, the bellows 100 is normally biased into its expanded condition shown in Fig. 1, and the bottom edge 102 of the sleeve 104 is closer to the float 80. Eventually, the float 80 is floated up quite near to the bottom edge 102 of the sleeve 104 and the reduced amount of air flow and air velocity through the sleeve 104 finally draws the float 80 to seat against the bottom edge 102.

When the vacuum cleaner is suctioning a mixture of liquid and air (and even when it is suctioning mixed particulate materials and air or air alone), the bellows 100 is collapsed by the air rushing through the sleeve 104, through the bellows 100 and through the sleeve 52 to the condition shown in Fig. 2, due to the increased pressure drop across the bellows. The bellows collapses far enough that the sleeve 104 moves out of the way of the lower edge 53 of the sleeve 52, and thus clearly raising the entrance port to the tank outlet away from the float 80. Eventually, the float 80 is floated up toward the bottom edge 53 of the sleeve 52. The increased air flow and air velocity through the sleeve 104 draws the float to seat against the bottom edge 102 while the float is further from the edge than in the case of Fig. 1.

Because the bottom edge 102 of the sleeve 104 is at different elevations at different air flow amounts and velocities through the sleeve 104, the liquid level at which the float 80 is drawn against the bottom edge 102 of the sleeve 104 to close off the outlet 50 from the tank is the same when the bellows 100 is in either of the conditions of Figs. 1 and 2.

The heights of the sleeve 52 and the sleeve 104, the height of the float 80 and the height of the floor 68 of the filter cage are all related for this purpose.

Although the present invention has been described in connection with a preferred embodiment thereof, many variations and modifications will now become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.

Claims (15)

1. A float seal for the air outlet from the tank of an electric vacuum cleaner, or the like, wherein the electric vacuum cleaner includes: a tank for collecting suctioned materials, including liquid; an inlet to the tank for suctioned materials; a suction motor connected to the tank for applying suction pressure to the tank, and an outlet from the tank communicating with the suction motor; the float seal comprising: the tank outlet comprising an opening communicating out of the tank and the opening being defined by a peripheral edge of the opening within the tank; a float, for floating up on liquid collected in the tank to the edge of the outlet opening; the float being cup-shaped, including a top end which projects up to the edge of the outlet, and the top end being wide enough to seat against the edge of the outlet, the top end being convexly rounded for being received in the opening and for seating against the edge of the outlet opening; the float including a bottom end, spaced away from the top end, and the bottom end being open; the cupshaped float having an open interior in open communication with the bottom end of the float; a float guide supported in the tank for defining a fixed pathway along which the float can float to the edge of the outlet opening, and the guide being directed to direct the top end of the float against the edge of the outlet opening for effecting a seal between the float and the edge of the outlet opening.

2. The float seal of claim 1, wherein the outlet from the tank comprises a sleeve having a free end which projects into the tank toward the float when the float is spaced away from the outlet, and the edge of the outlet opening being the free edge of the sleeve.

3. The float seal of claim 1, wherein the outlet opening is of a first width and the top end of the float is wider than the first width and the float flares wider toward the bottom end thereof than the first width and than the top end of the float.

4. The float seal of claim 3, wherein the outlet opening is defined by the edge thereof to be circular.

5. The float seal of claim 4, wherein the top end of the float comprises part of a sphere, which is a large enough portion of a sphere and extends down toward the bottom end of the float far enough that the spherical top end of the float engages the edge of the tank outlet.

6. The float seal of claim 5, wherein the float guide comprises a shaft supported in the tank, and the shaft projects through the open bottom end of the float and into the interior of the float without extending through the top end of the float; a fitting inside the float for supporting the float to slide along the shaft toward and away from the tank outlet.

7. The float seal of claim 1, wherein the top end of the float comprises part of a sphere, which is a large enough portion of a sphere and extends down toward the bottom end of the float far enough that the spherical top end of the float engages the edge of the tank outlet.

8. The float seal of claim 7, wherein the float, at least over the top end thereof which engages the edge of the tank outlet, is smooth and seamless.

9. The float seal of claim 8, wherein the entire float is an initially single piece, seamless element.

10. The float seat of claim 9, wherein the outlet opening is of a first width and the top end of the float is wider than the first width and the float flares wider toward the bottom end thereof than the first width and than the top end of the float.

11. The float seal of claim 7, wherein the float guide comprises a shaft supported in the tank, and the shaft projects through the open bottom end of the float element and into the interior of the float element, without extending through the top end of the float; a fitting inside the float for supporting the float to slide along the shaft toward and away from the tank outlet.

12. The float seal of claim 7, wherein the electric vacuum cleaner further includes a filter located at and extending around and enclosing the tank outlet, the float and the float guide; the filter being of a height that the float enclosed in the filter may move into engagement with and away from the edge of the tank outlet while inside the filter.

13. The float seal of claim 12, further comprising a filter cage located at and extending around and enclosing the tank outlet, the float and the float guide; the filter being supported on the filter cage; the filter cage having open areas through it, through which air may pass to the tank outlet and the filter being shaped to cover over the filter cage open areas, whereby air passing through the filter cage to the tank outlet passes across the filter.

14. The float seal of claim 13, wherein the float guide comprises a shaft supported to the filter cage, and the shaft projects through the open bottom end of the float and into the interior of the float without extending through the top end of the float; a fitting inside the float for supporting the float to slide along the shaft tow'ard and away from the tank outlet.

15. A float seal for the air outlet from the tank of an electric vacuum cleaner substantially as herein described with reference to, and as shown in, the accompanying drawings.