WO1994017717A1

WO1994017717A1 - Liquid pick-up appliances for use in surface cleaning or drying

Info

Publication number: WO1994017717A1
Application number: PCT/GB1994/000282
Authority: WO
Inventors: Charles Brooks; Michael Beard
Original assignee: Vax Limited
Priority date: 1993-02-13
Filing date: 1994-02-11
Publication date: 1994-08-18
Also published as: GB9302889D0; AU6006494A

Abstract

An appliance for picking up liquid by means of a suction head (50) which entrains the liquid in an air flow from said head to an air/liquid separator (200) and a collection container (350) for receiving liquid from the separator (200), valve means (259; 244) are provided which normally seal the collection container (350) to prevent escape of liquid therefrom when suction is not applied to the suction head (50), and valve operating means (270) are provided for positively setting the valve means (259; 244) to an open condition to allow liquid to enter the container (350). The valve means (259; 244) may comprise a movable valve element (250) which is biased into a closure position by resilient means (265) and a valve operating means may comprise a bellows (270) or other similar device responsive to the establishment of suction within the appliance. The valve means may be located within the air/liquid separator (100).

Description

Title: "Liquid pick-up appliances for use in surface cleaning or drying" Description of the invention

This invention relates to liquid pick-up appliances for use in surface cleaning or drying operations wherein liquid is picked-up for example from a floor surface (afforded by a floor or floor covering) or other surface such as afforded by a wall or window by a suction head so as to be entrained in air flow from such head to an air/liquid separator in which entrained liquid is separated from the air flow and collected in a container.

Such an appliance may be designed and used for drying floor surfaces or picking up spillages, but more usually will also incorporate a reservoir for a cleaning liquid (which may be water or a suitable cleaning solution) and means for delivering such liquid to a cleaning head, which may be incorporated in, or separate from, the suction head, so that the appliance is capable of carrying out, simultaneously or sequentially, floor cleaning and floor drying operations or similar operations on other surfaces.

Generally, such appliances have some provision for preventing over¬ filling of the collection container to avoid collected liquid being drawn back into the air flow whilst the impeller, which creates the air flow and the required suction at the head, is operative. Float valves are commonly employed for this purpose, as for example shown in British Patent specification 1601456 or in US Patent specification 3930281.

However, such float valves cannot prevent spillage from the collection container in the event that, for example, whilst unattended, the appliance is knocked over, or in the case of an appliance which is of the "vertical" type (i.e. not necessarily self-supporting in a stable upright position) falls over or is laid down after use. Under such circumstances collected liquid can drain from the container by two possible routes, namely back through the suction head and/or out through an air duct and impeller chamber from which, when the appliance is in use, air is discharged to atmosphere.

Little attention appears to have been paid to this in previous designs. For example, German Patent specification 1703220 shows only a simple flap valve between the collection container and the separator, which may not provide an effective seal under all circumstances.

According to the invention, an appliance for picking-up liquid includes a suction head which entrains the liquid in an air flow from said head to an air/liquid separator and a collection container for receiving liquid from said separator, and is characterised by the provision of valve means which normally seal the collection container to prevent escape of liquid therefrom when suction is not applied to the suction head, and valve operating means for positively setting the valve means to an open condition to allow liquid to enter the container.

In particular, the valve means may include a movable valve element which is biased into a closure position by resilient means, such as a spring. The valve operating means is preferably operatively associated with the establishment of air flow through the appliance so that the valve means is open only when the appliance is in use. For this purpose, the valve operating means may be electrically energised simultaneously with an impeller incorporated in the appliance, but preferably the valve operating means is responsive to a reduction in pressure at a point within the air flow path between the suction head and the impeller, or, where the impeller is incorporated into the appliance, an increase in pressure on the outlet side of the impeller.

In a preferred arrangement, bellows means are provided downstream of the separator, i.e. between the separator and the impeller where the impeller is incorporated into the appliance or between the separator and a connection to an external source of suction where the impeller is not incorporated in the appliance itself, to respond to a reduction of pressure downstream of the separator and move the valve element to its open condition. Alternatively, bellows means may be provided to respond to an increase in pressure at the outlet side of the impeller.

In either case, the bellows means is most conveniently of a kind which has two stable conditions, expanded and contracted, so that it changes abruptly from one condition to the other in response to a predetermined change in pressure so that the movable valve element itself is moved abruptly between the opened and closed positions.

Instead of bellows means, other fluid-pressure responsive means may be employed, including piston and cylinder arrangements, or pressure sensitive electrical switches to control an electrically operated valve element. Alternatively an electrically operable valve element may be movable to its open condition when a motor which drives the impeller is energised.

The valve means preferably includes separate sealing members to close the air flow passageway at two points, one between the collection container and the suction head, and the other between the collection container and the impeller. For this purpose, the valve means may comprise two concentric air flow ducts, one extending from an inlet into the separator and to the interior of the collection container, and the other extending from the interior of the collection container to an outlet connected to the source of suctionJhe sealing members being operative to close a respective one of said ducts. Preferably both of said sealing members are operatively associated with a single movable valve element. The two air flow ducts are conveniently of concentric form and the movable valve element may be of annular form with one of said sealing members disposed internally thereof, and the other externally.

The sealing members may be carried either by static parts of the valve means and/or by the movable valve element, in either case the sealing members being arranged to co-operate with complimentary seating surfaces.

Conveniently, the movable valve element is part of a movable assembly which also includes a tubular member defining an air flow duct between the movable valve element and the bellows means or the like, so that air flow is inwardly through an annular duct external to the movable valve element and outwardly through the interior of the movable element.

The valve means may include further sealing members which, in the open condition which permits air flow into and out of the collection container, serve to establish seals between the movable element and other adjacent parts defining the inner boundary of the annular duct of which the movable element forms a part.

The valve means may be separate from and additional to the separator, either with separate sealing members operative respectively upstream and downstream of the separator or with a single sealing member operative between the separator and the collection container.

However, in a preferred arrangement the valve means is disposed within the air/liquid separator, the latter being of annular form with the valve means disposed concentrically within it so as, when closed, to seal both the annular duct and the inner duct, and the annular duct of the valve means forming an active part of the separator.

Preferably, the annular duct of the separator comprises an annular intake chamber having a substantially tangential inlet from said suction head in a circumferential wall of the chamber, an annular outlet which opens in the axial direction relative to said circumferential wall, a frusto-conical deflector axially spaced from said intake chamber and in register with said annular outlet, an annular collection surface spaced radially outwardly from said deflector and the inner duct of the valve means comprises a central suction passageway extending between the space within said deflector and the source of suction, the arrangement being such that air flow with entrained liquid therein entering the intake chamber through the inlet is initially constrained into a circumferential flow with an axial component through the annular outlet and towards the deflector which imparts a radially outward component over the deflector whereby entrained droplets are thrown by centrifugal action onto the collection surface, the air being drawn inwardly around the periphery of the deflector and into the central suction passageway.

Around the annular outlet an internal frusto-conical surface may be provided to direct the out-going air flow radially inwardly towards an upper region of said deflector at a position spaced radially inwardly from the outer periphery thereof so as to maximise impact of entrained droplets onto the deflector.

Within the periphery of the frusto-conical deflector, an internal annular baffle may be provided at the in use underside thereof to interrupt the internal face of the deflector and prevent liquid being driven by internal air flow along such surface to the central suction passageway.

Preferably, the collection surface forms part of the collection container itself so as to provide an uninterrupted surface over which the collected liquid can flow away from the deflector and into the interior of the container.

In such a case, the collection container is preferably removable to enable the collected liquid to be emptied. For this purpose, the separator may include a radially outwardly directed annular seal externally of the intake chamber to engage sealingly with the collection surface and to allow the collection container to be assembled with, and removed from, the separator by movement in a generally axial direction.

Alternatively the air/liquid separator and the valve means in accordance with the invention may be formed as a structurally integrated unit which includes said collection surface around the deflector, and in this case it will be understood that the collection container will be adapted to receive liquid from said collection surface. In this case, the valve means may operate either to seal air flow passageways both upstream and downstream of the deflector or to seal a liquid inlet of the collection container.

These and other features of the invention will now be described by way of example with reference to the accompanying drawings wherein:-

FIGURE 1 shows in side view one embodiment of a floor cleaning appliance in accordance with the invention; FIGURE 2 shows a diametral section through a combined valve and air/liquid separator assembly incorporated therein, showing the valve in its open condition; and

FIGURE 3 shows a diametral section similar to that of Figure 2 with the valve in its closed condition.

A suction cleaner embodying a separator in accordance with the present invention, as illustrated in Figure 1 by way of example, includes a body 10 comprising a rear casing 110, an upper front casing 120 and a lower front casing 125 which in combination define a housing for the various operative components, including a motor/impeller unit 100 which provides a source of suction to draw air through a suction duct 180 and into an air/liquid separator and valve assembly 20. The casing components also define at the upper end of the body a handle 130 which is equipped with an electrical switch 131 to control energisation of the motor, and a trigger 132 which is coupled by means of a mechanical linkage system indicated diagrammatically at 133 to control the operation of a delivery valve 340 whereby a cleaning liquid can be dispensed from a removable container 30, by way of a delivery pipe 280 to a suction head 50 which is mounted by means of a swivel joint 40 within a lower extension 140 of the rear casing 110. The suction head 50 includes a removable cartridge assembly 60 whereby liquid delivered through pipe 280 can be applied to a floor surface to be cleaned. The suction head 50 also includes suction slots which communicate with the suction duct 180 whereby the floor surface may be dried.

The container 30 is removably located within an open-fronted recess 150 and affords an inner compartment 350 which is connected to the air/liquid separator and valve assembly 20 to receive recovered water.

Whilst the embodiment illustrated in Figure 1 includes provision for dispensing cleaning liquid from the removable container 30, it is to be understood that this is not a requirement of the present invention, and that accordingly the cleaning liquid storage and delivery features may be omitted. Likewise, whilst the illustrated embodiment incorporates a motor/impeller unit 100 for generating the required suction at the head 50, this unit may be omitted and instead the cleaner may be adapted for connection to an external source of suction, which may comprise either a free-standing unit coupled to the cleaner by means of a flexible hose or a remote installation including one or more suction points within the premises to be cleaned.

Moreover, whilst the embodiment illustrated is of the type in which the suction head is integrated with the body of the cleaner so that the whole appliance is supported and moved by the operator, the invention as hereinafter described may be incorporated into a free-standing collection unit to which the suction head is coupled by means of a flexible hose in well-known manner, in which case the suction head may be adapted for any of a range of operations involving liquid pick-up,including not only floor cleaning and floor drying but also for example wall or window cleaning.

The valve means in accordance with the invention, in the illustrated embodiment forms part of the separator and valve assembly 20 which includes an annular duct (I) which forms an active part of the separator 200 and a concentric inner duct (II) which forms part of the valve. The assembly 20 includes an intake chamber 210 having a cylindrical outer wall 211 with a tangential inlet 212 which is connected to the suction duct 180. The intake chamber 210 is formed with external mounting lugs 213 at diametrally opposed positions, whereby the assembly 30 is mounted within the body 10. At their under sides, the lugs 213 are formed with ribs 214 which serve to engage the upper edge of the inner compartment 350 of the container 30 to limit upward movement thereof and also to serve as pivot points to facilitate pivotal movement of the lower end of the container 30 into the lower end of the recess 150.

The intake chamber 210 has located centrally therein an inner member 215 with a central boss 216 having internal spacer ribs (not shown) and a cylindrical outer wall 217 which is spaced inwardly from the outer wall 211 of the intake chamber 210 to form an annular space 218 into which the tangential inlet 212 discharges. At a position below the level of the lower edge 219 of the wall 217, the intake chamber 210 is formed with an internal frusto-conical surface 220 which defines at its inner edge 221 an outlet opening. Externally of the frusto-conical surface 220, the intake chamber 210 is formed with an external groove 222 for the location of an external seal 223 which affords a flexible lip 223a. to engage the inside face of the inner compartment 350 of the container 30.

At its lower edge, the intake chamber 210 is formed with a circumferential lip 224 which supports and shields the seal 223 so that only the flexible lip 223a thereof is exposed to the upper end of the container 30 as this is presented to the assembly 20. The intake chamber 210 is also provided with three circumferentially spaced downwardly extending legs 225, formed with radially outwardly extending guide ribs 226 having upwardly and outwardly inclined edges 227 that can engage the upper rim of the inner compartment 350 of the container 30 as the latter is presented to the assembly 20. The legs 225 terminate in hooked end portions 228 which provide a bayonet connection for an external deflector member 230.

The deflector member 230 comprises a frusto-conical skirt 231 which is formed at its underside with a circumferential downwardly extending rib 232 at its outer periphery and, at a position spaced inwardly therefrom, a further annular rib 233. Slots 234 are formed adjacent to the rib 233 to receive the hooked end portions 228 of the legs 225, whereby the deflector member 230 is releasably carried by the intake chamber 210 so that it can be removed and cleaned as and when required by the user.

The skirt 231 is formed with a central boss 235, of which the lower part forms an annular rib 236 which projects downwardly at the inner edge of the skirt. At its upper end, the central boss 235 is formed with a pair of axially spaced external ribs 237 and 238 which locate between them an external seal 239 having a flexible lip 239a.

Within of the central boss 235, four radially extending vanes 241 support an inverted cone 242 at a position such that there is an annular gap 240 around the upper end of the boss 235. The cone 242 is formed with an external groove 243 around its periphery for a further external seal 244 having a flexible lip 244a_. so that the annular gap 240 is disposed between the seals 239 and 244 which are fixed in position and co-operate with respective complementary seating surfaces provided by a movable valve member assembly 250 as hereinafter described. Alternatively, either or both of such seals could be mounted on the movable assembly 250 to co-operate with complimentary seating surfaces in place of the seals 329 and 244 as described and illustrated.

In the illustrated embodiment the movable assembly 250 comprises a tubular member 251 defining an air outlet duct (II) having at its lower end an external frusto-conical skirt 252 which carries internally thereof a cylindrical ring 253 with an inclined in-turned rim 254 at its lower end. Circumferentially spaced hooked tongues 255 beneath the skirt 252, adjacent the lower end thereof, pass through slots 256 in an external flange 257 formed on the cylindrical ring 253 in order to secure the ring to the skirt. The flexible lip 239a. of the seal 239 maintains a wiping engagement with the inner surface of the ring 253. The flange 257 is spaced axially from the lower rim 258 of the skirt, and between the flange 257 and the rim 258 there is located a double-acting seal 259 with flexible lips 259a and 259b,

As can be seen from Figure 2, when the valve is in its open condition, an annular gap 260 is defined between the lower edge 221 of the intake chamber 210 and the rim 254 of the ring 253, such gap forming the outlet of the intake chamber.

The air outlet duct (II) defined by the tubular member 251 communicates with a bellows chamber 270 which is interposed between the duct and the motor/impeller unit 100 to operate the movable valve member assembly 250.

The bellows chamber 270 is defined by a flexible bellows member 271 of a kind which has a snap action and which is secured at its upper end by means of an internal rib 272 entering an external groove 121 formed around a central boss 122 afforded by a transverse wall 123 which forms part of the body assembly. The boss 122 having at its underside a tubular inlet 124 within which the upper end portion of the tubular member 251 is received with clearance. An internal rib 273 at the lower end of the bellows member 271 enters an external groove 274 which extends around the outer edge of a frusto-conical diaphragm member 275 which has a central dependent tube 276 located on tubular member 251 so as to be slidably received within the central boss 216 of the intake chamber 210 and guided for longitudinal movement by the spacer ribs (not shown) formed internally of the boss 216. Nibs 267 formed externally on the tubular member 251 retain the diaphragm member 275 in axial location relative thereto, with the lower end of the tube 276 engaging on a flat-topped annular step 268 formed externally at the junction of the skirt 252 and tubular member 251. A further flat-topped radial annular step 269 is disposed outwardly of the step 268 to engage the lower end of a compression spring 265 which at its upper end is located around the central boss 216 of the inner member 215. Alternatively a spring may be arranged to operate within the bellows chamber 270 between the boss 122 and the diaphragm member 275.

The spring 265 thus normally urges the valve member assembly 250 downwardly into its closed position as illustrated in Figure 3. In this position, the lower lip 259b of seal 259 engages the frusto-conical surface 220 around the outlet gap 260 of the intake chamber 210, which surface serves as a seating to co¬ operate with the seal 259 and prevent any collected water within the inner compartment 350 of the container 30 flowing back into the intake chamber 210 and escaping through the inlet 212 if, for example, the cleaner is laid flat on the floor. At the same time, the lip 244a of seal 244 is engaged with the underside of the skirt 252 which forms part of the movable valve member assembly 250 and affords a seating surface which co-operates with the seal 244 to prevent collected water escaping through the tubular member 251 into the motor/impeller unit 100 under those circumstances.

When the cleaner is in use, however, the operation of the motor/impeller unit 100 initially causes a reduction in pressure in the bellows chamber 270, whereby atmospheric pressure acting on the diaphragm member 275 overcomes the bias of compression spring 265 and by virtue of the snap action of the bellows member 271 throws the valve member assembly 250 rapidly into the open position as shown in Figure 2. This then allows air to be drawn in through the annular duct (I), that is from inlet 212, around the intake chamber 210, downwardly through the annular gap 260 into the interior of the inner compartment 350 of the container 30, and then through the inner duct (II), that is upwardly within the skirt 231, through the gap 240 around the cone 242, through the skirt 252 and tubular member 251, into and through the bellows chamber 270 and into the motor/impeller unit 100 from which it passes out to atmosphere.

In the open position of the valve member assembly 250 the lip 239a_. of seal 239 engages the inturned rim 254 of the cylindrical ring 253 which forms part of the movable valve member assembly and serves as a seating surface to co¬ operate with the seal 239 and prevent the air-flow by-passing the skirt 231 of the inner member 230 and entering the skirt 252 through the ring 253. At the same time, the upper lip 259a. of seal 259 engages the lower edge 219 of the wall 217 afforded by the inner member 215 which serves as a seating to co-operate with the seal 259 and prevent air being drawn in from atmosphere through the central boss 216 which guides the movable valve member assembly 250. Thus, seals 239 and 259 serve to close off gaps which would otherwise exist between the components which in combination define the inner surface of the annular air-flow duct (I) which extends between the inlet 212 and the interior of the inner compartment 350 of the container 30. Whilst the double seal 259 is carried by the movable assembly 250 to co-operate with fixed sealing surfaces it will be appreciated that alternatively two corresponding seals could be provided on the static assembly to co-operate with corresponding sealing surfaces afforded by the movable assembly 250.

Instead of coupling the movable assembly 250 to the diaphragm member 275 of the bellows chamber 270, it would be possible to employ a piston and cylinder device in which, for example, the diaphragm member is replaced by a piston slidably received within a cylinder which replaces the bellows chamber 270, the simple compression spring 265 preferably being replaced by a spring device designed to impart a snap action.

The intake chamber 210, inner member 215 and deflector member 230 form a static assembly comprising part of an air/water separator which is completed by the wall 310 of the inner compartment 350 of the container 30. A mixture of air and water entering through the inlet 212 is constrained into a tangential flow within the intake chamber between the cylindrical outer wall 211 and the cylindrical wall 217 and the in-coming air/water mixture is drawn downwardly through the gap 260 which forms the outlet of the chamber, where the internal frusto-conical surface 220 deflects the flow inwardly through the annular gap 260 so as to impinge on the skirt 231 at a position spaced inwardly from the periphery thereof. The continuing centrifugal action of the circulating air flow around the deflector member 230 facilitates the separation of entrained water droplets from the air flow and onto the inner surface 312 of the wall 310 of the inner compartment 350. Any water droplets collecting on the skirt 231 tend to flow gravitationally downwards to the rib 232, so that at that point they are subject to the centrifugal force of the circulating air flow again so as to be directed onto the wall of the inner compartment 350.

The annular rib 233 at the underside of the skirt 231 serves as a trap to prevent any film of moisture being driven upwardly at the underside of the skirt, and the annular rib 236 provides a second such barrier at the lower end of the central boss 235.

Whilst it is particularly convenient that the assembly 20 defines on the one hand an annular passageway which forms the air/liquid separator 200 and leads to the collection compartment 350 and on the other hand an inner passageway which leads from the collection compartment to the inlet opening 124 of the impeller chamber, with seals operating to close both such passageways under spring bias when the impeller is inoperative, other arrangements within the scope of the present invention are possible.

For example, the diaphragm member 275 or its equivalent may be operatively connected to a separate valve arranged upstream of the inlet 212 to the intake chamber 210; instead of forming a composite valve integrally with the separator, separate valves may be associated with the air/liquid inlet and the air outlet of the separator; instead of operating such valves mechanically by bellows means or the like, they could be actuated electro-mechanically by means for example of a solenoid controlled by a pressure responsive switch having a pressure sensor at an appropriate point in the air flow passageway or connected so as to be energised with the electric motor driving the impeller when the motor/impeller unit 100 is incorporated into the cleaner.

Further, whilst it is convenient to arrange the separator and valve assembly 20 within the inner compartment 350 of the container 30 so that an inner surface of the compartment serves directly as a collection surface for centrifugally separated droplets as above-described, other arrangements are also possible. For example, the collection surface may form part of the assembly 20 rather than part of the container 30. In such a case, the seal 223 would be replaced by a seal acting between a liquid outlet at the underside of the separator and the collection compartment to receive the separated liquid. Thus, the assembly 20 could include a cylindrical outer wall equivalent to the upper end of the collection compartment as illustrated, and such outer wall may terminate at its lower end in a frusto-conical internal skirt which at its centre defines a liquid outlet in register with the upper end of the collection container. Such outer wall may be received within the upper end of the collection container and be spaced inwardly therefrom so that a seal similar to the seal 223 may be provided to act between the outer wall of said modified separator and valve assembly and the upper end of the collection container. Alternatively, a sealing ring could be disposed around the liquid outlet to co-operate with a corresponding inlet at the upper end of the collection container without the separator and valve assembly entering the upper end of the collection container.

In such cases, where the air flow between the air/liquid inlet and the air outlet of the separator and valve assembly does not enter into the collection compartment (as it does in the illustrated embodiment) it would be possible to utilise a valve member which closes the liquid outlet of the separator and valve assembly or the inlet opening of the collection container. Thus, the movable assembly 250 may in such a case include a downward extension below or within the skirt 231 and having for example an inverted conical member similar to the cone 242 to enter and seal the liquid outlet at the base of the separator and thereby prevent escape of liquid from the collection container.

Moreover, whilst it is convenient for the separator and valve assembly 20 to be incorporated into the body 10 of the cleaner, it may alternatively be integrated with the container 30 so as to be removable therewith. In such a case, the seal 223 may be omitted and the wall of the collection compartment may be united with the intake chamber 210, and instead releasable connections may be provided to connect the inlet 212 of the intake chamber to the suction duct 180 and to connect the outlet of the bellows chambers 270 or the equivalent to the inlet of the impeller chamber.

Although it is desirable for the container 30 to be removable from the body 10 for the purpose of emptying the contents of the collection container 350 (and filling a reservoir compartment where provided) it would be possible for the collection container to be assembled with or integrated into the body in a manner such that removal thereof is not required, means being provided for draining the container, such as an outlet duct at its lower end with an associated valve.

Claims

1. An appliance for picking up liquids comprising a suction head (50) which entrains the liquid in an air flow from said head to an air/liquid separator (200) and a collection container (350) for receiving liquid from said separator, characterised by the provision of valve means (259;244) which normally seal the collection container (350) to prevent escape of liquid therefrom when suction is not applied to the suction head (50), and valve operating means (270) for positively setting the valve means (259;244) to an open condition to allow liquid to enter the container (350).

2. An appliance according to Claim 1 wherein the valve means (259;244) includes a movable element (250) which is biased into a closure position by resilient means (265).

3. An appliance according to Claim 2 wherein the valve operating means (270) is operatively associated with the establishment of air flow through the appliance so that the valve means (259;244) is open only when the appliance is in use.

4. An appliance according to Claim 3 wherein the valve operating means (270) is responsive to a reduction in pressure at a point within the air-flow path through the appliance.

5. An appliance according to Claim 4 wherein the valve operating means comprises bellows means (270) provided downstream of the separator (200).

6. An appliance according to Claim 5 wherein an impeller (100) is incorporated into the appliance as a source of suction and the bellows means (270) is arranged in the air flow path between the separator (200) and said impeller (100).

7. An appliance according to Claim 5 which is intended for connection to an external source of suction and wherein the bellows means (270) is arranged between the separator (200) and a connector for said external source of suction.

8. An appliance according to any one of Claims 5 to 7 wherein the bellows means (270) is of a kind which has two stable conditions, expanded and contracted, and changes abruptly from one condition to the other in response to a predetermined change in pressure so that the movable valve element (250) itself is moved abruptly between the opened and closed positions.

9. An appliance according to Claim 1 wherein the valve means (259;244) includes separate sealing members to close the air-flow passageway at two points, one (259) between the collection chamber (350) and the suction head (50), and the other (244) between the collection container (350) and the source of suction (100).

10. An appliance according to Claim 9 wherein the valve means includes two concentric air-flow ducts (1,11), one (I) extending from an inlet (212) into the separator (200) to the interior of the collection container (350), and the other (II) extending from the interior of the collection container (350) to an outlet (124) connected to the source of suction (100), the sealing members (259;244) being operative to close a respective one of said ducts (1,11).

11. An appliance according to Claim 10 wherein the movable valve element (250) is common to both of said sealing members (259;244).

12. An appliance according to Claim 11 wherein the movable valve element (250) is of annular form with one of said sealing means (244) disposed internally thereof, and the other (259) externally.

13. An appliance according to Claim 12 wherein the movable valve element (250) is part of a movable assembly which also includes a tubular member (251) defining an air-flow duct between the movable valve element (250) and the valve operating means (270), so that air flow is inwardly through an annular duct (I) external to the movable valve element (250) and outwardly through an inner duct (II) within the interior of the movable element (250).

14. An appliance according to Claim 13 wherein the valve means includes further sealing members (239;259a) which, in the open condition which permits air flow into and out of the collection container, serve to establish seals between the movable element (250) and other adjacent parts (253;217) defining the inner boundary of the annular duct (I) of which the movable element forms a part.

15. An appliance according to Claim 13 wherein the valve means is disposed within the air/liquid separator (200), the latter being of annular form with the valve means (259;244) disposed concentrically within it so as, when closed, to seal both the annular duct (I) and the inner duct (II), and the annular duct (I) of the valve means forming an active part of the separator (200).

16. An appliance according to Claim 15 wherein the annular duct (I) of the separator (200) comprises an annular intake chamber (210) having a substantially tangential inlet (212) from said suction head (50) in a circumferential wall (211) of the chamber (210), an annular outlet (260) which opens in the axial direction relative to said circumferential wall (211), a frusto-conical deflector (230) axially spaced from said intake chamber (210) and in register with said annular outlet (260), an annular collection surface (312) spaced radially outwardly from said deflector (230) and the inner duct (II) of the valve means comprises a central suction passageway extending between the space within said deflector(230) and the source of suction (100), the arrangement being such that air flow with entrained liquid therein entering the intake chamber (210) through the inlet (212) is initially constrained into a circumferential flow with an axial component through the annular outlet and towards the deflector (230) which imparts a radially outward component over the deflector (230) whereby entrained droplets are thrown by centrifugal action onto the collection surface (312), the air being drawn inwardly around the periphery of the deflector (230) and into the central suction passageway.

17. An appliance according to Claim 16 wherein an internal frusto-conical surface (220) is provided around the annular outlet (260) of the separator to direct the out-going air flow radially inwardly towards an upper region of said deflector (230) at a position spaced radially inwardly from the outer periphery thereof so as to maximise impact of entrained droplets onto the deflector (230).

18. An appliance according to Claim 16 wherein the collection surface (312) forms part of the collection container (350) itself so as to provide an uninterrupted surface over which the collected liquid can flow away from the deflector (230) and into the interior of the container (350).

19. An appliance according to Claim 18 wherein the collection container (350) is removable to enable the collected liquid to the emptied.

20. An appliance according to Claim 19 wherein the separator (200) includes a radially outwardly directed annular seal (223) externally of the intake chamber (200) to engage sealingly with the collection surface (310) and to allow the collection container (350) to be assembled with, and removed from, the separator (200) by movement in a generally axial direction.

21. A combined air/liquid separator and valve means for an appliance in accordance with anyone of the preceding claims, and substantially as hereinbefore described with reference to and as shown in Figures 2 and 3 of the accompanying drawings.