GB2338174A

GB2338174A - Water-bath separation system for vacuum cleaner and method for cooling motor

Info

Publication number: GB2338174A
Application number: GB9808985A
Authority: GB
Inventors: James Peter Thomson
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-04-27
Filing date: 1998-04-27
Publication date: 1999-12-15
Anticipated expiration: 2018-04-27
Also published as: GB2338174B; GB9808985D0

Abstract

A water bath vacuum cleaner comprises bath 14 and a fan assembly 17. A cleaning air inlet 16 directs air from a vacuum cleaner hose onto the surface of the bath. To prevent dust and water from entering the fan, a mechanical separator 24 is provided which includes a central void communicated with the inlet of assembly 17 and slotted or perforated walls. The separator is fast with the assembly and extends through aperture 22 in wall 21. Air bleeds through clearance space 23 to prevent dirt and water entering the fan housing by this route. The motor (4, fig. 1) is cooled by means of a cooling air discharge passage terminating within the air outlet passage, extending in the downward direction thereof and having an open end. Air forced through the outlet passage by the fan induces a vacuum in the discharge passage, causing air to be drawn into the motor housing to cool the motor and then drawn into the outlet passage.

Description

2338174 1 IMPROVEMENTS IN AND RELATING TO VACUUM CLEANERS This invention

relates to certain improvements in and relating to vacuum cleaners. The invention is particularly applicable to improvements in water bath vacuum cleaners, but certain aspects of the invention may be more generally applicable to other vacuum cleaner designs.

Water bath vacuum cleaners employ a water bath for the purpose of removing dirt particles from air flowing through the vacuum cleaner. Typically, a fan is used to draw air into the vacuum cleaner, and the air inlet to the vacuum cleaner is designed so that the inflowing air is directed to a water bath. Dirt particles, when they impinge on the water bath, will be retained and the air is withdrawn from the water bath housing to be discharged to the exterior of the vacuum cleaner. A mechanical separator is provided to prevent water droplets and dirt particles from leaving the water bath housing.

A typical prior art water bath vacuum cleaner is shown in GB-A-2181042. It will be noted that the design is relatively complex and accordingly expensive to manufacture.

One feature of the design shown in GB-A-2181042 is that the fan motor is housed in an inner canister positioned within a cap assembly. Means are provided for enabling cooling air to be drawn into the inner canister and then to egress from the inner canister into the surrounding cap assembly and to egress from the cap assembly to the exterior of the vacuum cleaner.

According to a first aspect of the present invention a vacuum cleaner having a fan assembly for drawing air into the vacuum cleaner and a motor for driving the fan assembly comprises a cleaning air outlet passage for discharge of cleaning air from the fan assembly; a housing surrounding the motor; means for permitting cooling air to flow into the housing; and a cooling air discharge passage extending 2 from the motor housing to the cleaning air outlet passage, the cooling air discharge passage terminating in a portion which (1) is located within the cleaning air outlet passage, (2) extends in the downstream direction thereof, and (3) is open at the downstream end thereof whereby, in use, air forced through the cleaning air outlet passage by the fan assembly will cause a vacuum in the cooling air discharge passage and will accordingly cause air to be drawn into the motor housing to cool the motor and subsequently to be drawn into the cooling air discharge passage for discharge into the cleaning air outlet passage.

Such an arrangement facilitates cooling of the motor with clean air drawn from the ambient surrounding the cleaner, and permits discharge of the used cooling air from the cleaner with the used cleaning air. If desired a fan may be provided to assist the flow of cooling air, but it is believed in many applications the use of cooling air fan will not be necessary and sufficient cooling air flow can be induced by means of the positioning of the cooling air discharge passage terminal portion within the cleaning air outlet passage. It is also believed that an enhanced cooling effect can be obtained if the flow of cooling air into the motor housing from the ambient is restricted. Under these circumstances, the cooling air discharge passage arrangement will result in a sub-ambient pressure in the motor housing. Accordingly, as air enters the motor housing from the ambient it will be subject to a substantially adiabatic expansion which will result in a reduction in the temperature in the air. Accordingly, the cooling air, as it enters the motor housing, will have a lower temperature than it would have if it was forced into the housing by a fan. This will result in enhanced cooling of the motor.

Whilst, in the preferred embodiment of the invention, the above aspect of the invention is utilized in the context of a water bath vacuum cleaner, it will be appreciated that it is of general applicability to vacuum cleaner designs.

According to a second aspect of the invention there is provided an improved and simplified arrangement for the separator and fan of a water bath vacuum cleaner. According to this aspect of the present invention a water bath 111 -- 3 vacuum cleaner comprises a water bath housing and a fan housing, the water bath housing and fan housing being separated by a wall; a motor driven fan located in the fan housing for drawing air from the water bath housing; a separator secured to the fan for rotation therewith, the separator having a peripheral wall with passages extending therethrough and a central void in communication with the inlet to the fan, and extending from the fan through an aperture in the wall so that the majority of the separator is located within the water bath housing; and a small clearance passage between the separator and the aperture in the wall so that a small volume of air from the fan housing can bleed through the clearance passageway into the water bath housing to prevent the flow of water droplets or dirt from the water bath housing to the fan housing around the exterior of the separator.

It will be appreciated that because of the action of the fan the pressure in the fan housing will be higher than the pressure in the water bath housing. Accordingly, by providing a clearance passage surrounding the separator at the point where it passes through the wall between the fan housing and the water bath housing a small amount of air may be bled back to the water bath housing from the fan housing to prevent the flow of water droplets or dirt around the outside of the separator into the fan housing. Accordingly, the only flow route available from the water bath housing to the fan housing is via the separator with the resultant removal of water droplets and dirt from the air flow. This arrangement substantially eliminates the relatively complex labyrinth seal arrangement provided in prior art water bath vacuum cleaners to prevent the bypassing of the separator.

The separator may be supported entirely by the fan or may be supported by means of a bearing mounted on a spider secured to the wall. In the preferred embodiment of the invention the separator is formed with a shoulder which extends parallel to the wall for a short distance radially outwardly of the aperture, thereby further inhibiting the entry of water splashes into the region of the clearance space.

1 1 4 The above and further features and advantages of the invention will be understood from the following description of preferred embodiments thereof, given by way of example only, reference being had to the accompanying drawings wherein:

Figure 1 illustrates schematically and in cross-section a portion of a vacuum cleaner; and Figure 2 illustrates schematically a second portion of a vacuum cleaner.

Referring firstly to Figure 1, there is shown the upper portion (1) of a vacuum cleaner. The vacuum cleaner may be of the water bath type, but could equally be of other designs. The illustrated upper part of the vacuum cleaner comprises a fan assembly (2) located within a fan assembly housing (3) and a fan motor (4) located within a motor housing (5). A cleaning air outlet passage (6) extends from the fan housing (3) and, in use, cleaning air is discharged through the cleaning air outlet passage to the exterior of the vacuum cleaner. Cleaning air is drawn into the fan assembly (2) via an inlet (7). In the lower part of the vacuum cleaner means will be provided for separating dirt and, optionly, water from the air flow induced by the fan assembly (2) and accordingly substantially clean air only will be drawn through the fan inlet (7).

A cooling air discharge passage (8) extends from the motor housing (5) to the cleaning air outlet passage (6). The cooling air discharge passage (8) terminates in a portion (9) which is located substantially coaxially within the cleaning air outlet passage (6) and extends in the downstream direction thereof. The terminal portion (9) terminates in a mouth (10) which faces the downstream direction. As will be appreciated by those skilled in the art, the flow of air through the cleaning air outlet passage caused by operation of the fan (2) will cause a reduced pressure in the cooling air discharge passage (8). The terminal portion (9) of the cooling air discharge passage may be shaped in conventional manner to optimise the pressure reduction achieved by the cleaning air flow.

The motor housing (5) is provided with fresh air inlets (11) but is otherwise substantially closed. Accordingly, the reduced pressure in the cooling air passage (8) will cause reduced pressure within the motor housing (5) which will draw air through the inlets (10) to flow over or through the motor (4). Preferably, the inletss (11) constitute a flow restrictor so that air flowing from the ambient into the housing (5) will experience a substantially adiabatic expansion as it passes through the inlets and will accordingly be reduced in temperature as compared with the ambient. This will enhance the cooling effect of the air.

It will be appreciated that the fan housing (3) and the motor housing (4) are substantially isolated from each other by a dividing wall. The dividing wall may be provided in part by a mounting ring (12) for the fan assembly and in part by the wall (13) of the fan assembly.

The above described arrangement allows the motor to be cooled with clean air drawn from the ambient (as distinct from cleaning air) and facilitates a forced flow of air over or through the motor without the use of a motor cooling fan. It should be appreciated, however, that if desired a motor cooling fan may be utilised together with the vacuum induced cooling air flow arrangement described.

Referring now to Figure 2 there is shown schematically the lower portion of a water bath vacuum cleaner. As will be understood by those skilled in the art such a vacuum cleaner comprises a water bath (14) in the bottom of a water bath housing (15). A cleaning air inlet (16) directs air from a vacuum cleaner hose or fixed pipe installation downwardly to impinge on the surface of the water bath. This action causes dust and dirt particles to be trapped by the water. A fan assembly (17) is located in a fan housing (18) above the water bath housing (15) for the purpose of creating a vacuum within the water bath housing so as to draw cleaning air into the water bath housing through the inlet (16). The fan is driven by a motor (not shown). In order to prevent dust and water particles from entering the fan a mechanical separator (24) is provided within the water bath housing. The separator includes a central void which is in communication with the inlet of the fan assembly (17) through an open top, slotted or perforated walls, and a closed 6 base. Accordingly, air from the water bath housing (15) must flow through the slots or perforations of the rotating separator in order to reach the inlet of the fan. Any water droplets present in the air will tend to impinge on the separator and be flung radially outwardly, i.e. back into the water bath housing by the separator. Accordingly, only substantially clean air flows through the void into the fan inlet.

It will be noted that in the illustrated embodiment the separator (24) is secured directly to the fan (17) for rotation therewith. The end of the separator (24) remote from the fan is provided with a bearing (19) which is supported by a spider (20) itself secured to a wall (21) which separates the water bath housing from the fan housing. The use of a bearing (19) and spider (20) may not be required in certain instances.

The separator (18) extends from the fan (17) through an aperture (22) provided in the wall (21). A small working clearance is provided between the separator (18) and the aperture (20). The fan (17) ensures that the pressure within the fan housing (18) is higher than the pressure within the water bath housing (15). Accordingly, a small continuous flow of air will pass from the fan housing (18) into the water bath housing (15) via the clearance gap (23) provided between the aperture (22) and the separator (18). This flow will prevent passage of dirt and water droplets from the water bath housing (15) into the fan housing (18) via the clearance (23). Accordingly, the only available route for flow from the water bath housing (15) to the fan housing is via the interior of the separator (18).

It will be appreciated that the above arrangement provides a simple and effective means of preventing the flow of air containing water droplets or dirt particles from the water bath housing (15) to the fan housing (18) via the exterior of the separator. The arrangement is considerably simpler than the labyrinth seal type arrangements of the prior art.

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Claims

CLAIMS:

1. A water bath vacuum cleaner comprising: a water bath housing and a fan housing, the water bath housing and fan housing being separated by a wall; a motor driven fan located in the fan housing for drawing air from the water bath housing; a separator secured to the f an for rotation therewith, the separator having a peripheral wall with passages extending therethrough and a central void in communication with the inlet to the fan, and extending from the fan through an aperture in the wall so that the majority of the separator is located within the water bath housing; and a small clearance passage between the separator and the aperture in the wall so that a small volume of air from the fan housing can bleed through the clearance passageway into the water bath housing to prevent the flow of water droplets or dirt from the water bath housing to the fan housing around the exterior of the separator.

2. A vacuum cleaner according to claim 1 wherein the separator is supported entirely by the fan.

3. A vacuum cleaner according to claim 1 wherein the separator is supported by means of a bearing mounted on a spider secured to the wall.

4. A vacuum cleaner according to any preceding claim wherein the separator is formed with a shoulder which extends parallel to the wall radially outwardly of the aperture to inhibit the entry of water splashes into the region of the clearance space.

19

5. A vacuum cleaner according to any preceding claim comprising a cleaning air outlet passage for discharge of cleaning air from the fan assembly; a motor housing surrounding the motor; means permitting cooling air to flow into the motor housing; a cooling air discharge passage extending from the motor housing to the cleaning air outlet passage, the cooling air discharge passage terminating in a portion which is located within the cleaning air outlet passage, extends in the downstream direction thereof, and is open at the downstream end thereof whereby, in use, air forced through the cleaning air outlet passage by the fan assembly will cause a vacuum in the cooling air discharge passage and will accordingly cause air to be drawn into the motor housing to cool the motor and subsequently to be drawn into the cooling air discharge passage for discharge into the cleaning air outlet passage.

6. A vacuum cleaner substantially as hereinbefore described with reference to the accompanying drawings.