Abstract
An automatic filter cleaning system e.g for cleaning a filter in a vacuum cleaner. The cleaning system has an electrical motor that drives/rotates, directly/indirectly, a piston which directly/indirectly opens a filter cleaning valve. The filter cleaning valve may open for a filter cleaning back flow air stream that thus cleans the filter. The piston is spring loaded and a piston guide ensures that the energy accumulated in the spring and piston is released during the rotation of the piston, thereby shortly opening the filter cleaning valve.
Claims
1. An automatic filter cleaning system comprising: an electrical motor configured to drive/rotate, directly or indirectly, a piston configured to control the compression of one or more compression spring(s); and one or more filter cleaning valve(s) configured to open for one or more filter cleaning back flow air stream(s) to flow into one or more filter(s), where the filter cleaning valve is configured to be activated, directly or indirectly, by the piston and a piston guide, wherein the piston guide and the one or more compression spring(s) are arranged to convert rotary movement of the piston into an axial movement of the piston.
2. An automatic filter cleaning system according to claim 1, wherein the piston comprises a piston slide feature that is configured to only slide on the piston guide sliding surface during a spring compression phase of one rotation of the piston.
3. An automatic filter cleaning system according to claim 1, wherein the piston has a piston slide feature that is configured not to slide on the piston guide sliding surface during a spring decompression phase of one rotation of the piston.
4. An automatic filter cleaning system according to claim 1, wherein an outer part of the piston is made of plastic material and has a piston core made of higher density material e.g. metal.
5. An automatic filter cleaning system according to claim 1, wherein the electrical motor is an AC synchronous motor.
6. An automatic filter cleaning system according to claim 1, wherein the electrical motor has an inbuilt gearbox configured to reduce speed and increase torque.
7. An automatic filter cleaning system according to claim 1, wherein the one or more filter cleaning valve(s) is made of plastic material.
8. An automatic filter cleaning system according to claim 1, wherein a weight of the piston is above 150 g.
9. An automatic filter cleaning system according to claim 1, wherein the one or more compression spring(s) has a spring constant larger than 3 N/mm.
10. An automatic filter cleaning system according to claim 1, wherein a return spring is arranged to facilitate the piston to be returned to an initial position by pushing toward a distal end of the piston.
11. An automatic filter cleaning system according to claim 10, wherein the return spring is arranged at a bottom portion of the piston guide.
12. An automatic filter cleaning system according to claim 3, wherein the piston slide feature protrudes from the piston and extends radially with respect to a longitudinal axis of the piston.
Description
DESCRIPTION OF THE DRAWING
[0026] Preferred embodiments of the present invention are described with reference to the accompanying drawings, wherein:
[0027] FIG. 1 shows a vacuum cleaner in ISO view;
[0028] FIG. 2 shows a vacuum cleaner in side view with and without tank;
[0029] FIG. 3 shows a vacuum cleaner top view with indication for cross sectional view;
[0030] FIG. 4 shows the cross-sectional view defined in FIG. 3;
[0031] FIG. 5 shows internal parts of the vacuum cleaner and the filter cleaning valve actuator;
[0032] FIG. 6 shows the filter cleaning system in Position 1;
[0033] FIG. 7 shows the filter cleaning system in Position 2;
[0034] FIG. 8 shows the filter cleaning system in Position 3;
[0035] FIG. 9 shows the piston guide and piston slide and
[0036] FIG. 10 shows the movement of the piston and filter cleaning valve during use
DETAILED DESCRIPTION
[0037] FIG. 1 illustrates a vacuum cleaner 1 in an ISO view consisting of a head 2 and a tank 4 with a suction hose 3.
[0038] FIG. 2 illustrates the vacuum cleaner 1 without the tank 4, thereby showing the filter 21, which during suction of dust will become clogged, and thus, may need to be cleaned in order restore sufficient air flow/suction of the vacuum cleaner 1. The finer the dust is, the faster the filter 21 gets clogged, resulting in a decrease of suction.
[0039] In FIG. 3, shows a top view of the vacuum cleaner 1 showing a section cutting plane A-A indicated in FIG. 4.
[0040] In FIG. 4, the cross sectional view A-A of FIG. 3 is shown. The vacuum cleaner motor 41 creating the air suction in the vacuum cleaner 1 is illustrated. The filter 21 filtering the air, before exhausted, flowing into the vacuum cleaner 1 is also shown. The filter cleaning valve 42 is also shown. When the filter cleaning valve 42 opens, the filter cleaning back flow air stream flows into the filter and backwards through the filter due to under pressure inside the tank. Thus, the filter 21 is cleaned. A filter cleaning actuator 43 is also visualised.
[0041] In FIG. 5, the head 2)is shown. Several parts have been omitted to better illustrate the filter cleaning actuator 43. The filter cleaning actuator 43 is composed of an electrical motor 53, a piston 52 and a piston guide 51. The shaft of the electrical motor 53 rotates the piston 52 in the direction shown by the piston rotation direction arrow 54.
[0042] In FIG. 6, Position 1 for the piston 52 in the filter cleaning actuator 43 is shown. In Position 1, the compression spring 61 is not compressed. A return spring 62 is also shown, facilitating the return to Position 1 of the piston 52. The piston 52 may have an inner piston core 64 made of a higher density material to increase the weight of the piston, and thereby the impact of the piston 52 when hitting/opening the filter cleaning valve 42. A piston shaft 63 connected to the shaft of the electrical motor 53 drives the piston 52. In Position 1 of the piston 52, the filter cleaning valve 42 is closed.
[0043] In FIG. 7, Position 2 for the piston 52 is shown. The compression spring 61 is now fully compressed, as the Piston 52 has moved up (shown by direction arrow 71) due to the axial rotation of the piston 52 and the shape of the piston guide 51. The filter cleaning valve 42 is closed.
[0044] In FIG. 8, Position 3 for the piston 52 is shown. The energy accumulated during the spring compression phase is now released and the piston 52 moves down (shown by direction arrow 81). Thereby, the filter cleaning valve 42 is activated and opened (show by direction arrow 82). A “hammer effect” is created by the piston 52 on the filter cleaning valve 42, forcing it to open shortly. The filter cleaning air steam 83 enters the inside of the filter 21 shortly and cleans the filter 21 due to the under pressure inside the tank 4. This filter cleaning operation is accomplished in a very short time and the piston 52 returns to Position 1, whereby the filter cleaning valve 42 closes.
[0045] In FIG. 9, a more detailed view of the filter cleaning actuator 43 is shown. As can be seen, the piston 52 has a piston slide feature 92 enabling sliding on a piston guide sliding surface 91 on the piston guide 51. The piston guide 51 also has a piston guide non-sliding surface 93, e.g. a steep surface onto which the piston 5) cannot slide on. When the piston slide feature 92, during rotation, has reached the piston guide non-sliding surface 93, the energy accumulated in the compression spring 61 and piston 52 is released, and the piston 52 moves down and hits the filter cleaning valve 42, thereby opening it shortly. Thus, depending on the rotation speed of the electrical motor 53 and the number of slide/non sliding surfaces 91, 92 on the piston guide 51, the time between each filter cleaning can be controlled. In general, the period could suitably be 20-30 seconds. In the shown system, no complex control electronics are needed to control the electrical motor 53 as it just runs continuously when the vacuum cleaner (1) is turned on. If customers do not want to use the automatic filter cleaning system, a simple inexpensive switch configured to stop the electrical motor 53 can be integrated.
[0046] FIG. 10 illustrates the cycle if the piston 52 and the filter cleaning valve 42. In FIG. 10, the piston 52 starts the cycle in Position 1. The filter cleaning valve 42 is closed. Due to the rotation of the piston 52, the piston will gradually compress the compression spring 61 until the maximum compression is reached in Position 2. The filter cleaning valve 42 remains closed. Thus, Position 1 through Position 2 is denoted the spring compression phase 101. The piston 52 is then released from the sliding surface on the piston guide 51 and moves down to Position 3, thereby also activating/opening the filter cleaning valve 42. Due to the return spring 62 and the flow forces on the filter cleaning valve 42, the piston 51 rapidly returns to Position 1. The filter cleaning valve 42 is thereby opened shortly and creates an impulse cleaning of the filter 21. The suction performance of the vacuum cleaner 1 is only reduced shortly. Thus, Position 2 through Position 1 via Position 3 is the spring decompression phase 102.
Nomenclature
[0047] 1. Vacuum cleaner
[0048] 2. Head
[0049] 3. Hose
[0050] 4. Tank
[0051] 21. Filter
[0052] 41. Vacuum cleaner motor
[0053] 42. Filter cleaning valve
[0054] 43. Filter cleaning actuator
[0055] 51. Piston guide
[0056] 52. Piston
[0057] 53. Electrical motor
[0058] 54. Piston rotation direction arrow
[0059] 61. Compression spring
[0060] 62. Return spring
[0061] 63. Piston shaft
[0062] 64. Piston core
[0063] 71. Piston direction upwards movement
[0064] 81. Piston direction downwards movement
[0065] 82. Filter cleaning valve open movement
[0066] 83. Filter cleaning back flow air stream
[0067] 91. Piston guide sliding surface
[0068] 92. Piston slide feature
[0069] 93. Piston guide non sliding surface
[0070] 101: Spring compression phase
[0071] 102: Spring decompression phase
