GB2311598A

GB2311598A - A portable dust extractor

Info

Publication number: GB2311598A
Application number: GB9606662A
Authority: GB
Inventors: Philip Wren
Original assignee: Black and Decker Inc
Current assignee: Black and Decker Inc
Priority date: 1996-03-29
Filing date: 1996-03-29
Publication date: 1997-10-01
Also published as: GB9606662D0

Description

A PORTABLE DUST EXTRACTOR The present invention relates to a portable dust extractor.

A dust extractor according to the present invention is particularly useful in connection with hand tools and power tools, such as a drill. It is well known that when using power drills to drill holes in building materials such as plaster, brick or plasterboard, a considerable amount of waste material in the form of dust is created. This dust falls to the floor and on to skirting boards and other surfaces. This dust has to be removed and causes considerable inconvenience.

The present invention seeks to provide a portable dust extractor which enables the waste material to be removed from a work site, such as a hole being drilled, and be stored in a suitable collection chamber so that the dust does not come into contact with surfaces such as carpets and skirting boards from which is subsequently has to be cleaned.

The present invention also seeks to provide a portable dust extractor which is easy to use leaving the operator with both hands free to use the power drill or other tool.

The present invention further seeks to provide a portable dust extractor which can be used with a relatively wide range of drill or other tool sizes.

According to the present inventor, there is provided a portable dust extractor comprising a suction device, a dust collection chamber, a limpet device which in use allows access to a work site and a flexible hose providing communication between the suction deice and the limpet device, wherein the suction device can cause a vacuum to form within the limpet device, such that the limpet device is held against a surface of the work site, and dust produced at the work site is sucked along the flexible hose and deposited in the dust collection chamber.

Preferably the suction device and the dust collection chamber are rigidly connected together, during use, to form a single unit.

Further, the single unit is preferably adapted to be carried as a back pack or mounted on a waist belt.

In a particular embodiment, the limpet device comprises at least two compartments which are in fluid communication with each other, one of the compartments having an opening to provide access to the work site for a tool and the other compartment having an outlet which is connected to the flexible hose, the compartments being connected by at least one fluid passage which can be at least partially closed off by a valve.

Preferably sealing means are included to allow each compartment to be sealed to a surface of a work site.

The sealing means can be arranged around the periphery of each of the compartments and the sealing means can comprise a strip of compressible materials such as synthetic or natural rubber.

The at least two compartments can be contained within a single housing.

The at least two compartments can be divided from each other by means of two lengths of sealing material with a gap provided between the lengths of sealing material to allow air to flow through the at least one fluid passage.

The opening can be reinforced eg with a steel washer or bush to allow access for a tool such as a drill to the surface to be drilled.

The limpet device can be provided with a valve allowing the vacuum to be released from within the limpet device.

The valve can be in circular form or in the form of a slide.

Preferably the limpet device is formed from a transparent material so that the user can see the surface which is to be drilled or operated upon.

The two compartments can be connected by two tubes, the flow through one of which is controlled by a valve.

In another arrangement, the two tubes are combined in effect into a single tube having a control valve and the control valve has an opening enabling a lower flow of air to pass through the tube when the valve is closed and suction applied. Operation of the valve enables larger pieces of debris to flow to the outlet in order to prevent blockage.

The valve can be located at the inlet to the tube or downstream of the inlet to the tube.

In a preferred embodiment the suction device is a cyclone dust extractor.

If so, the cyclone dust extractor may comprise a housing defining a first cyclone separator and a second cyclone separator in series, a fan for producing cyclones within the cyclone separators and a motor for driving the fan, wherein at least one of the cyclone separators has an inlet portion and an outlet portion which are separated by a wall.

By providing a wall between the inlet flow and the outlet flow of a cyclone separator, less turbulence occurs in the separator and the speed of flow for both the inlet flow and the outlet flow can be controlled more accurately.

Preferably the outlet portion of the at least one cyclone separator acts as a third cyclone separator. In such an arrangement, the outlet portion of the at least one cyclone separator is preferably reverse rifled to assist in extracting dust from the air flow.

The end of the wall separating the inlet portion and the outlet portion of the at least one cyclone separator preferably includes a diffuser (or baffle) for assisting in separating the inlet cyclone from the outlet cyclone. More particularly, the diffuser can assist in directing the inlet flow away from the outlet flow.

Preferably the wall between the inlet portion and the outlet portion of the at least one cyclone separator defines an inlet passageway with an outer wall and an outlet passageway with an inner wall which both have crosssectional areas which reduce on progressing along the passageways.

In a preferred embodiment, the inner wall of the outlet portion of the at least one cyclone separator acts as an outer wall for the second cyclone separator.

A dust collector may be situated between the inlet portion and the outlet portion of the first cyclone separator. Further, a baffle is preferably provided in the dust collector to help discharge dust particles carried by the cyclone.

The dust collector preferably can be separated from the housing to discharge dust particles collected in the chamber or chambers of the collector.

The second cyclone separator preferably comprises three stages, a first stage decelerating the cyclone, a second stage accelerating the cyclone and a third stage decelerating the cyclone. As a result, improved extraction of dust from the cyclone can be achieved.

The third stage of the second cyclone separator may be situated within the dust collector. As a result, dust extracted by the second cyclone separator can be discharged from the dust extractor at the same time as that from the first cyclone separator.

The second cyclone separator preferably includes a frusto-conical outlet passageway communicating with the fan.

The broader end of the frusto-conical outlet is adjacent to the fan, thereby causing dust to be deposited in the cyclone separator before the air of the cyclone reaches the fan.

The housing is preferably provided with a tangential inlet port communicating with the first cyclone separator.

The extractor may include a belt clip for attaching the extractor to a belt of a user.

As a result of being extremely efficient, a portable dust extractor according to the present invention may be battery operated.

Specific embodiments of the present invention are now described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic perspective view of a portable dust extractor according to the present invention; Figure 2 shows a plan view of one form of limpet device which may be used in a portable dust extractor according to the present invention; Figure 3 shows an elevation of the limpet device shown in Figure 2; Figure 4 shows a view on arrow A" in Figure 2; Figure 5 shows a modified form of the limpet device shown in Figures 2 to 4 inclusive; Figure 6 shows a side elevation of a modified form of limpet device to that shown in Figure 5; Figure 7 shows a part view on arrow "B" in Figure 6; Figure 8 is a perspective view from above and one side of a cyclone dust extractor which may be used in a portable dust extractor according to the present invention; Figure 9 is a perspective view from above and the other side of the cyclone dust extractor of Figure 7; and Figure 10 is a sectional side view of the cyclone dust extractor of Figure 8.

With reference to Figure 1 of the drawings, a portable dust extractor (1) according to the present invention is shown. The portable dust extractor (1) comprises a portable vacuum source (3), which may be a cyclone dust extractor as described hereinafter with reference to Figures 8-10, a flexible hose (5) and a limpet device (7). Embodiments of limpet device are also described in detail hereinafter, with reference to Figures 2-7 of the accompanying drawings.

In use, the vacuum source (3) is carried by a user, perhaps on the back of the user via straps or mounted on a waist belt of the user, and the limpet device (7) is placed against a surface to be drilled, for example. The vacuum source (3) is energised and a vacuum is formed in the limpet device (7) to stick the limpet device (7) to the surface.

Drilling of the surface can then begin, and any dust or debris produced by the drill bit is sucked away from the work site along the flexible hose (5) and into a collection chamber of the vacuum source (3).

Specific details of the components of the portable dust extractor 1 will now be described.

Referring to Figures 2 to 4 there is shown a limpet device (7) comprising a housing (12) provided with a peripheral seal (14). The seal (14) can be in the form of a length or lengths of a compressible material such as natural or synthetic rubber. The sealing material being secured to the housing by means of an adhesive.

The housing (12) is divided into two compartments (16) and (18) which are separated from one another by two lengths of sealing material (20) and (22). Two gaps are provided between the lengths of sealing material (20) and (22) to allow air to flow through two tubes (24) and (26). The axis of the tube (24) is approximately tangential to the compartment (16).

The two tubes (24,26) are of different diameters the tube (26) being of a greater diameter than the tube (24).

The tube (24) extends from the compartment (16) into the outlet (38) and the tube (26) also extends from the compartment (16) into the outlet (38) as shown more clearly in Figure 2.

Tube (26) is also provided with a spring loaded valve (28) which can be operated by a pivotally mounted lever (30) against the force of a spring (32).

The compartment (16) is provided with an access opening (34) and the access opening is provided with a reinforcement in the form of a steel washer or bush (36). The access opening can by typically about i inch or slightly larger in diameter so that the limpet device can be used together with a range of the most common drill sizes used.

The flexible hose (5) is attached to the housing (12) by means of a connector (42). The other end of the flexible hose (5) is provided with an attachment means (not shown) to allow the hose to be secured to the inlet of the vacuum source (3) such as a cyclone dust extractor.

In use the housing (12) is positioned on a surface eg.

a wall or ceiling so that the access opening (34) is aligned with the position of the hole which is to be drilled. The vacuum source (3) is switched on and air will be drawn through the access opening and through the tubes (24) and (26) and then into the flexible hose (5) creating a suction within the housing (12) and the suction will maintain the housing (12) in position on the surface. The seals (14), (20) and (22) prevent air entering the housing other than through the access opening (34).

The power drill (not shown) can then be held with both hands free from the limpet device and the drill bit inserted through the access opening (34) and the drill operated to form the hole.

The operation of the valve (28) to allow air to flow through the tube (26) allows the suction effect to be released and for the limpet device (7) to be removed from the work surface. It will be appreciated that if the limpet device (7) is attached to a ceiling the valve (28) is operated by a force which tends to hold the limpet device (7) in position so that when the suction effect is released the limpet device (7) does not fall from the ceiling.

Operation of the valve (28) also allows for larger pieces of debris to flow to the vacuum source without causing a blockage. When the valve (28) is closed there is a fluid flow through the tube (24) all the time suction is being applied. When the valve (28) is opened there will be an air flow through both tubes (24) and (26) and larger pieces of debris can flow through the tube (26).

It will be appreciated that while the vacuum source still operates air will be drawn through the annular gap between the drill bit and the access opening (34) and there will be a flow of air through the tubes (24) and (26) drawing waste material from the drilled hole to the outlet (38) via the tubes (24,26) which terminate in the outlet (38). The flow of air and waste material then passes into the hose (5) and the collection chamber of the vacuum source. Once the hole has been drilled the vacuum source can be switched off whilst holding the housing (12) in position and the housing (12) can then be removed from the surface which has been drilled.

The housing can also be provided with a slide valve.

The slide valve can comprise simply a length of material which can be moved in guides between a closed position so that it covers an opening in the housing or it can be slid for example by using a thumb to reveal the opening and therefore release the suction within the housing. If such a valve is provided in the housing the vacuum source can be left running, the valve operated and the housing can be moved to another location for a further hole to be drilled.

In an alternative arrangement the valve can be in the form of a circular plate having an opening which can be rotated into register with an opening in the housing in order to release the suction within the housing.

Referring to Figure 5 the smaller tube (24) has been dispensed with and the valve (28) has been modified by the provision of a cut-out (28A) so that all the time suction is being applied there will be an air flow through the tube (26). The inlet to the tube (26) is located in the same position as the inlet to the tube (24) shown in Figure 1, that is tangentially to the opening (34). The valve (28) is shown in the open position. If a blockage occurs due to larger pieces of debris the valve (28) can be lifted and the larger pieces of debris can flow through the tube (26) to the outlet (30). Operation of the valve (28) as described with reference to Figures 2 to 4 also enables the suction effect to be released. The location of the inlet of the tube (26) approximately tangential to the opening (34) enables the air flow and the accompanying debris to flow directly into the tube (26).

Referring to Figures 6 and 7, the valve (28) has been removed downstream from the inlet of the tube (26). The valve (28) has been modified so that it now operates as a slide. A spring (not shown) urges the valve into the closed position as shown. A screw (52) located in a slot (28B) in the valve (28) can be used to clamp the valve in a desired position. The length of tube upstream of the valve (28) allows larger pieces of debris to collect whilst still allowing drilling to continue. These larger pieces of debris can be released when drilling has ceased by opening the valve (28) whilst suction is maintained.

It is preferably that the tube (26) extends a substantial way, for example 30 cm or more into the outlet (38). Such an arrangement enables dust to be carried away and prevents dust settling in the larger compartment (18), particularly when working on a horizontal surface.

It has been found that virtually no waste material escapes from the limpet device and this therefore avoids the need for any cleaning up to be conducted after drilling operations have ceased.

It is preferred that the housing (12) is formed from a transparent material such as Perspex (Registered Trade Mark) which allows the operator a clear view of the surface to be drilled enabling the housing to be correctly positioned at the location which has previously been marked for a hole to be drilled.

Turning now to Figures 8-10 of the drawings, a cyclone dust extractor (101) for acting as the vacuum source (3) in a portable dust extractor (1) according to the present invention comprises a housing (103) having an inlet (105) and an outlet (107), a motor (109) for driving a centrifugal fan (111), a dust collector (113) and a belt clip (115).

The housing (103) includes a battery compartment (117) which accommodates a battery (not shown) for driving the motor (109) via switch gear (119). In use, the portable cyclone dust extractor (101) can be clipped onto a user's belt by means of the belt clip (115) and the motor (109) can be energised using the switch gear (119) to drive the centrifugal fan (111) to suck dust and debris into the dust extractor (101) via the flexible hose (5) and the inlet (105). The dust and debris is then separated from the air flow by means of cyclone separators within the housing (103) which will be described in more detail hereinafter.

When dust and debris has been separated from the air flow, it accumulates in the dust collector (113). Since the dust collector (113) can be separated from the housing (103), collected dust can be emptied from the collector (113) and deposited in any suitable waste disposal site.

The collector (113) can then be reattached to the housing (103) for further use of the dust extractor (101).

With particular reference to Figure 10 of the drawings, the inlet (105) of the dust extractor (101) communicates with a first cyclone separator (123) and the outlet (107) communicates with a second cyclone separator (125) via the centrifugal fan (111). Each of the cyclone separators (123,125) has a respective inlet portion (127,129) and an outlet portion (331,333). In the case of the first cyclone separator (123), a wall (135) separates the inlet portion (127) from the outlet portion (131) along virtually the complete length of the two portions (127,131). In contrast, a frusto conical wall (137) of the second cyclone separator (125) extends only part way into the second cyclone separator (125) such that the inlet (129) and outlet (133) portions of the separator (125) are not completely separated.

As mentioned above, the first cyclone separator (123) includes a dividing wall (135) between the inlet portion (127) and the outlet portion (131) of the separator (123).

This wall (135) forms a first converging passageway (139) with the housing wall (141) as shown in Figure 10. As air is drawn in through the tangential inlet (105), the air rotates around the channel (139) within the housing (103) and proceeds down the passageway to the narrower end. The air therefore accelerates and, on exiting the end of the passageway (139) into a collection chamber (143), is immediately decelerated, thereby depositing large dust and debris particles in the collection chamber (143) of the dust collector (113). This action is typical of many prior art cyclone separators and is fundamental to the working thereof. The wall (135) carries a diffuser (145) which directs the cyclonic air flow away from the outlet portion (131). A further baffle (147) is provided in the collection chamber (143) against which large dust and debris particles collide, thereby assisting in removing the dust and debris from the air flow and depositing it in the collection chamber (143).

The outlet portion (131) of the first cyclone separator (123) carries the rotating air flow from the collection chamber (143) upwards towards the top of the housing (103).

As the air rises, the passageway narrows, thereby accelerating the air flow. The wall (135) acts as an outer wall of the second portion (131), an inner wall (149) of which diverges and approaches the separating wall (135). As the air flows upwards against gravity, the effect of gravity causes some of the dust and debris particles to fall back down into the collection chamber (143). Although not specifically shown in the drawings, reverse rifling may be formed on the walls (135,149) within the outlet portion (131) to assist in this process. Hence, this outlet portion (131) of the first cyclone separator (123) acts as a third cyclone separator.

On reaching the top of the outlet portion (131) of the first cyclone separator (123), the rotating air flow passes through an opening (151) and into the second cyclone separator (133). The air descends down the inside of the diverging wall (149) and, on passing the end of the frusto conical wall (137), decelerates to cause further dust particles to drop out of the cyclone. These particles fall into a second dust collection chamber (153), which is formed inside the first dust collection chamber (143). The cyclone continues down the second cyclone separator (133) and enters this second dust collection chamber (153) before rising again through an opening in the frusto conical wall (137) and out of the outlet (107) via the fan (111).

On approaching the second dust collection chamber (153), the air flow is accelerated due to the tapering of the diverging wall (149). Thus, on entering the dust collection chamber (153) the cyclone is allowed to expand, thereby decelerating and releasing further dust particles. Three stages therefore exist in the second cyclone separator (133), namely deceleration, followed by acceleration and subsequent deceleration of the cyclone.

As mentioned above, when sufficient dust and debris has been collected in the collection chambers (143,153) of the dust collector (113), the collector (113) can be disconnected from the housing (103) to be emptied. On re engagement of the collector (113) with the housing (103), the cyclone dust extractor (111) is once again ready for action.

As will be appreciated, by using cyclone separators (123,133), there is no need for vacuum cleaner bags and the like which can get clogged and subsequently waste energy.

Hence, the cyclone dust extractor (111) is particularly efficient and, consequently, suitable for use with a battery pack rather than a mains power source.

By virtue of the wall (135) between the inlet portion (127) and the outlet portion (331) of the first cyclone separator (123), as mentioned above there is effectively formed a third cyclone separator within the dust extractor (101). Hence, far improved extraction of dust and debris from an air sample results.

The use of the portable dust extractor according to the present invention is not limited to use with power tools and it can be used in conjunction with hand tools if needs be.

It will also be appreciated that a portable dust extractor according to the present invention enables the dust extractor to be accurately located and leaves the operator with both hands free to use the power tool or the hand tool as the case may be.

It will of course be understood that the present invention has been described above purely by way of example, and that modifications of detail can be made within the scope of the invention.

Claims

1. A portable dust extractor comprising a suction device, a dust collection chamber, a limpet device which in use allows access to a work site and a flexible hose providing communication between the suction device and the limpet device, wherein the suction device can cause a vacuum to form within the limpet device, such that the limpet device is held against a surface of the work site, and dust produced at the work site is sucked along the flexible hose and deposited in the dust collection chamber.

2. A portable dust extractor as claimed in claim 1, wherein the suction device and the dust collection chamber are rigidly connected together, during use, to form a single unit.

3. A portable dust extractor as claimed in claim 2, wherein the single unit is adapted to be carried as a back pack or mounted on a waist belt.

4. A portable dust extractor as claimed in any preceding claim, wherein the limpet device comprises at least two compartments which are in fluid communication with each other, one of the compartments having an opening to provide access to the work site for a tool and the other compartment having an outlet which is connected to the flexible hose, the compartments being connected by at least one fluid passage which is at least partially closed off by a valve.

5. A portable dust extractor as claimed in claim 4, wherein the at least one fluid passage extends from the opening to the outlet.

6. A portable dust extractor as claimed in claim 4 or claim 5, wherein the valve is provided with an opening enabling air to flow from the opening to the outlet.

7. A portable dust extractor as claimed in any one of claims 4 to 6, wherein two fluid passages extend between the opening and the outlet, one of said passages having a valve to close off fluid flow through the passage.

8. A portable dust extractor as claimed in any one of claims 4 to 7, wherein the valve is located at the entrance to the at least one fluid passage.

9. A portable dust extractor as claimed in any one of claims 4 to 6, wherein the valve is located downstream of the inlet to the at least one fluid passage.

10. A portable dust extractor as claimed in any one of claims 4 to 9, wherein each compartment includes sealing means for sealing the compartment to a surface, the sealing means comprising a strip of compressible material and being arranged around the periphery of each of the compartments.

11. A portable dust extractor as claimed in any one of claims 4 to 10, wherein the at least two compartments are contained within a single housing.

12. A portable dust extractor as claimed in any one of claims 4 to 11, wherein the at least two compartments are divided from each other by means of two lengths of sealing material with a gap provided between the lengths of sealing material to allow air to flow from one compartment to the other.

13. A portable dust extractor as claimed in any one of claims 4 to 12, wherein the opening is reinforced.

14. A portable dust extractor as claimed in any one of the preceding claims, wherein the limpet device is provided with a valve to allow the vacuum to be released.

15. A portable dust extractor as claimed in claim 14, wherein the valve is in circular form or in the form of a slide.

16. A portable dust extractor as claimed in any preceding claim, wherein the limpet device is formed from a transparent material.

17. A portable dust extractor as claimed in any preceding claim, wherein the suction device is a cyclone dust extractor.

18. A portable dust extractor as claimed in claim 17, wherein the cyclone dust extractor comprises a housing defining a first cyclone separator and a second cyclone separator in series, a fan for producing cyclones within the cyclone separators and a motor for driving the fan, wherein at least one of the cyclone separators has an inlet portion and an outlet portion which are separated by a wall.

19. A portable dust extractor as claimed in claim 18, wherein the outlet portion of the at least one cyclone separator acts as a third cyclone separator.

20. A portable dust extractor as claimed in claim 18 or claim 19, wherein the outlet portion of the at least one cyclone separator is reverse rifled to assist in extracting dust from the cyclone.

21. A portable dust extractor as claimed in any one of claims 18 to 20, wherein the end of the wall separating the inlet portion and the outlet portion of the at least one cyclone separator includes a diffuser for assisting in separating the inlet cyclone from the outlet cyclone.

22. A portable dust extractor as claimed in any one of claims 18 to 21, wherein the wall between the inlet portion and the outlet portion of the at least one cyclone separator defines an inlet passageway with an outer wall and an outlet passageway with an inner wall, the cross-sectional areas of the passageways reducing on progressing along the passageways.

23. A portable dust extractor as claimed in any one of claims 18 to 22, wherein an inner wall of the outlet portion of the first cyclone separator acts as an outer wall for the second cyclone separator.

24. A portable dust extractor as claimed in any one of claims 18 to 23, wherein the dust collection chamber is situated between the inlet portion and the outlet portion of the first cyclone separator.

25. A portable dust extractor as claimed in claim 24, wherein a baffle is provided in the dust collection chamber to help discharge dust particles carried by the cyclone.

26. A portable dust extractor as claimed in claim 24 or claim 25, wherein the dust collection chamber can be separated from the housing to discharge dust particles collected in the chamber.

27. A portable dust extractor as claimed in any one of claims 18 to 26, wherein the second cyclone separator comprises three stages, a first stage decelerating the cyclone, a second stage accelerating the cyclone and a third stage decelerating the cyclone.

28. A portable dust extractor as claimed in claim 27, wherein the third stage of the second cyclone separator is situated within a dust collection chamber.

29. A portable dust extractor as claimed in any one of claims 18 to 28, wherein the second cyclone separator includes a frusto-conical outlet passageway communicating with the fan.

30. A portable dust extractor as claimed in any one of claims 18 to 29, wherein the housing is provided with a tangential inlet port communicating with the first cyclone separator.

31. A portable dust extractor as claimed in any one of claims 18 to 30, wherein a belt clip is provided on the outside of the housing.

32. A portable dust extractor as claimed in any preceding claim, which is powered by a battery accommodated in the suction device.

33. A portable dust extractor substantially as hereinbefore described with reference to and as shown in the accompanying drawings.